Download: Combined Service Manual f’- (\’ ( HP LaserJet 4L/ 4ML (C2003A/ C2015A)

Combined Service Manual f’- ‘\ (\’ ( HP LaserJet 4L/ 4ML (C2003A/ C2015A) / HP LaserJet 4P/ 4MP (C2005A/ C2040A), 0 Copyright Hewlett- Warranty WARNING Packard Company 1993 The information contained Electrical Shock Hazard in this document is subject To avoid electrical shock, All Rights Reserved. Repro- to change without nc,tice. use only supplied power duction, adaptation, or cords and connect only to translation without prior Hewlett-Packard makes written pmnnssionis pro- no warranty of any kind properly grounded (3-hole) hibited, except as allowed with regard to this mate- wall outlets. under the copyright laws. rial, including, but not limited to, the implied Publication number warranties or merchant- C2005-90988 ability and fitness for a particular purpose. First edition, August 1993 Hewlett-Packard shall not Second edition, March 1994 be liable for errors cm- Printed in USA tained herein or for inciden- tal or consequential damaged in connecti~m with the furnishing, per- formance, or use of this ma- terial. \ Hewlett-Packard Company 11311 Chinden Boulevard Boise, Idaho 83714,

Conventions

This manual uses the following conventions: Unless specifically stated otherwise, information applies to all four printer models (LaserJet 4L/4ML/4P/4MP), Most procedures are com- bined for all printers, except where they differ substantially. Color is used to emphasize items which are important to the material under discussion. The names of major printer parts and assemblies are Capitalized. Bold is used for emphasis, particularly in situations where italic type would be confusing. Italic type is used to indicate related documents or emphasis. COME’UTER type indicates text as seen on a computer monitor. Di ;W.-ii’+type indicates text as seen on the printer’s 16 character LCD display panel (LaserJet 4P/4MP only). ~ indicates keys on a computer keyboard or on the printer’s control panel (LaserJet 4P/4MP only). Examples include ~ and m. ,“ Notes contain important information set off from the text. i,,21.JII[!,’J Caution messages alert you to the possibility of damage to equipment or loss of data. WARNING! Warning messages alert you to the possibility of personal injury., A detailed matrix of printer features is followed by general information on the four printer models. Specifications, major assembly locations, safety and regulatory information are all included. The chapter ends with a discussion of the service and repair philosophy along with useful information on obtaining technical help. Recommendations pertaining to the physical location of the printer and consumables are followed by general print media specifications (including specifications for paper, envelopes, labels and transparencies). Chapter 3 provides the step-by-step installation and setup procedure, along with detailed information on using the Control Panel for each printer model. Sample self tests and printer reset information are also included. Turn to this chapter for information on routine printer maintenance, including consumables and printer cleaning procedures. Paper jam procedures are also included. Here you will find the basic theory-of-operation information required to understand the various printer systems and how they function together. This chapter contains the step-by-step procedures for replacing all the printer’s field replaceable units (FRUS). Assemblies are grouped by physical location in the printer. ..., Turn to Chapter 7 for diagnosing and troubleshooting printer problems. Start with the general troubleshooting flowchart, referencing the paper path and printer component location diagrams for assistance. Error message tables and image defect samples are followed by engine test and other diagnostic procedures. The chapter ends with more troubleshooting tools such as an image defect ruler and wiring diagram. I-JseChapter 8 to find any field replaceable unit (FRU) in the printers. Exploded view drawings are accompanied by complete part number and description tables. The parts index is a convenient tool for looking up any field replaceable unit (FRU). All parts are sorted both by part number and by part name. Parts are cross-referenced to their corresponding exploded view illustrations in Chapter 8. This appendix contains cabling and pin-out information for the serial, parallel and LocalTalk interfaces which are supported by the printers. lJse the subject index to quickly locate any information in the manual. iv, Fig l-l Sample Model and Serial Number Labels – 1-3 Fig I-2 External Assembly Locations (LaserJet 4L/4ML) -1-6 Fig I-3 External Assembly Locations (LaserJet 4P/4MP) -1-7 Fig I-4 Internal Assembly Locations (all printers) – 1-8 Fig I-5 LaserJet 4L Internal Assembly Locations – 1-9 Fig I-6 LaserJet 4P Internal Assembly Locations – 1-10 Fig 2-1 Printer Space Requirements – 2-3 Fig 2-2 Distributing Toner – 2-6 Fig 3-1 Attaching the Help Labe”ls (LaserJet 4L/4ML) – 3-6 Fig 3-2 LaserJet 4L/4ML Front Control Panel – 3-9 Fig 3-3 LaserJet 4P/4MP Front (;ontrol Panel – 3-12 Fig 3-4 LaserJet 4P/4MP Menu Map – 3-14 Fig 3-5 Service Mode Menu Map (LaserJet 4ML/4P/4MP) -3-16 Fig 3-6 LaserJet 4L Self Test Page – 3-20 Fig 3-7 LaserJet 4MP Service Mt]de Self Test Page – 3-22 Fig 3-8 Engine Test Button and Printout (LaserJet 4L) – 3-25 Fig 4-1 Service Checkpoints – 4-2 Fig 4-2 Sample 5% Page Coverage – 4-4 Fig 4-3 Paper Feed Area Jam – 4-9 Fig 4-4 Clearing Jams from the Toner Cartridge Area – 4-10 Fig 4-5 Clearing Jams from the l’aper Guide – 4-10 Fig 4-6 Releasing Paper from the Fusing Assembly – 4-11 Fig 4-7 Clearing Jams from the Fuser Area – 4-12 Fig 5-1 Printer Functional Block Diagram – 5-2 Fig 5-2 DC Controller Loads – 5-3 Fig 5-3 Top Cover/Toner Cartridge Plunger – 5-6 Fig !i-4 Power Supply Block Diagram – 5-9 Fig 5-5 High Voltage Power Timing – 5-11 Fig 5-6 Formatter Block Diagram – 5-12 Fig 5-7 EconoMode vs. Regular F’rint – 5-18 Fig 5-8 Image Formation Block Diagram – 5-22 Fig 5-9 Photosensitive Drum – 5-23 Fig 5-10 Drum Surface Potential -5-24 Fig 5-11 Drum Cleaning – 5-25 Fig 5-12 Primary Charging Roller – 5-26 Fig 5-13 Image Writing – 5-27 Fig 5-14 Image Development – 5-29 Fig 5-15 Developing Potentials – 5-30 Fig 5-16 Transferring Stage – 5-3:1 Fig 5-17 Fusing Film and Pressure Roller – 5-32 Fig 5-18 Printer Paper Path – 5-34 Fig 5-19 Oblique Roller Paper Alignment – 5-37 v, Fig 6-1 Phillips vs. Posidriv Screwdrivers – 6-3 Fig 6-2 Memory Module (LaserJet 4L) – 6-4 Fig 6-3 SIMM Access Panel (LaserJet 4P/4MP) – 6-5 Fig 6-4 Power Access Door (LaserJet 4L/4ML) – 6-6 Fig 6-5 Printer Cover Screws (Laser,Jet 4L/4ML) – 6-7 Fig 6-6 Releasing the Printer Cover Rear Tabs – 6-8 Fig 6-7 Control Panel Connector (LaserJet 4P/4MP) – 6-9 Fig 6-8 Printer Cover Screws (Laser, Jet 4P/4MP) – 6-10 Fig 6-9 Cover (LaserJet 4P/4MP) – 6-11 Fig 6-10 Rear Door – 6-12 Fig 6-11 Control Panel Assembly (LaserJet 4P/4MP) -6-13 Fig 6-12 Control Panel RFI Shield (LaserJet 4P/4MP) -6-14 Fig 6-13 Formatter Shield and PCA – 6-15 Fig 6-14 DC Controller Connector& Switch Actuator – 6-16 Fig 6-15 Gear Train Assembly – 6-17 Fig 6-16 Screw Tightening Sequence Example – 6-18 Fig 6-17 Main Motor – 6-19 Fig 6-18 Oblique Roller Assembly – 6-20 Fig 6-19 Tray Forms Size Guide – 6-21 Fig 6-20 Paper Cassette Assemblies – 6-22 Fig 6-21 Laser/Scanner Assembly – 6-23 Fig 6-22 Fan – 6-24 Fig 6-23 Power Switch Assembly (LaserJet 4P/4MP) – 6-25 Fig 6-24 Paper Guide/Roller Assembly – 6-26 Fig 6-25 Transfer Roller -6-27 Fig 6-26 Beam-to-Drum Mirror – 6-29 Fig 6-27 Fusing Assembly – 6-30 Fig 6-28 Fusing Pressure Plate – 6-31 Fig 6-29 Upper Fusing Assembly – 6-32 Fig 6-30 Fuser Delivery Assembly – 6-33 Fig 6-31 Lower Delivery Roller – 6-34 Fig 6-32 Lower Delivery Guide and Exit Sensor Flag – 6-35 Fig 6-33 Fuser Connector Assembly – 6-36 Fig 6-34 Upper Output Roller Assembly – 6-37 Fig 6-35 Lower Output Rollers – 6-38 Fig 6-36 DC Controller Assembly – 6-40 Fig 6-37 Pickup Feed Roller Solenoid – 6-41 Fig 6-38 Machine Screw Locations (DC Controller PCA) – 6-43 Fig 6-39 Metal Backing Plate – 6-44 Fig 6-40 DC Controller PCA – 6-45 Fig 6-41 D-Roller – 6-46 Fig 6-42 Pickup Feed Roller Assembly (side view) – 6-47 Fig 6-43 Pickup Feed Roller Assembly (bottom view) – 6-48 Fig 6-44 Feeder Guide Assembly – 6-49 Fig 6-45 Small Media Roller Assembly – 6-50 Fig 6-46 Static Eliminator Strip – 6-51 Fig 6-47 Toner Cartridge Lever Assembly – 6-52 Fig 6-48 Top Cover Switch {Plunger Assembly) -6-53 Fig 6-49 Releasing the Side Tabs – 6-.54 vi, Fig 6-50 DC Controller/Scanner Connector Location – 6-55 Fig 6-51 Input Paper Sensor Arm -6-56 Fig 7-1 Paper Path and Components – 7-4 Fig 7-2 DC Controller PCA Components – 7-5 Fig 7-3 Top Door/T’oner Cartridge Plunger Assembly – 7-9 Fig 7-4 Engine Test Button and Printout (LJet 4L/4ML) -7-36 Fig 7-5 Defeating the Top Door Plunger (LJet 4P/4MP) – 7-37 Fig 7-6 Defeating the Exit Sensor Flag (LaserJet 4P/4MP) – 7-38 Fig 7-7 Leading Edge Adjustment – 7-43 Fig 7-8 Beam -to-Dru]m Mirror Adjustment – 7-45 Fig 7-9 Repetitive Image Defect Ruler – 7-46 Fig 7-10 Main Wiring Diagram – 7-47 Fig 8-1 Assembly Locations – 8-7 Fig 8-2 Covers and Doors (LaserJet 4L/4ML) – 8-8 Fig 8-3 Covers and Doors (LaserJet 4P/4MP) – 8-10 Fig 8-4 Internal Components 1 – 8-12 Fig 8-5 Internal Components 2 – 8-14 Fig 8-6 Internal Components 3 – 8-16 Fig 8-7 DC Controller Assembly – 8-18 Fig 8-8 Gear Train Plate Assembly – 8-20 Fig 8-9 Paper Cassette (LaserJet 4L/4ML) – 8-21 Fig 8-10 Paper Cassette (LaserJet 4P/4MP) – 8-22 Fig 8-11 Pickup Assemb] y – 8-23 Fig 8-12 Fuser Assembly – 8-24 Fig 8-13 Keyboard Overlay (LaserJet 4P/4MP) – 8-26 Fig B-1 Parallel Cable Pin Assignments – B-2 Fig B-2 Serial Pin-outs DB-25 to DB-9 – B-3 Fig B-3 Serial Pin-outs DB-9 to DB-9 – B-3 Fig B-4 Connecting to END of a LocalTalk Network – B-4 Fig B-5 Connecting to MIDDLE of a LocalTalk Network – B-5 vii, Tbl 1-1 Printer Dimensions – 1-4 Tbl 1-2 Performance Specifications -1-4 Tbl 1-3 Environmental Specifications – 1-5 Tbl 1-4 Electrical Specifications – 1-5 Tbl 1-5 Related Documentation – 1-19 Tbl 2-1 Current Requirements (Amps) – 2-2 Tbl 2-2 Printer Operating Dimensions – 2-3 Tbl 2-3 Toner Cartridge Environmental Conditions – 2-4 Tbl 2-4 Supported Media Sizes – 2-!3 Tbl 2-5 Selected Paper Specifications – 2-11 Tbl 2-6 Envelope Speciilcations–212 Tbl 2-7 Adhesive Label Specifications – 2-14 Tbl 2-8 Transparency Specifications – 2-15 Tbl 3-1 Front Panel Button Usage -3-11 Tbl 3-2 Menu of Resets (LaserJet 4“P/4MP) – 3-27 Tbl 4-1 Life Expectancy of Consumi~bles – 4-3 Tbl 4-2 Cleaning Printer Components – 4-6 Tbl 5-1 Solenoids – 5-35 Tbl 5-2 Photosensors – 5-35 Tbl 5-3 Print Period Descriptions – 5-40 Tbl 7-1 Paper Out Error -7-7 Tbl 7-2 Paper Jam Error – 7-8 Tbl 7-3 Door Open Error – 7-9 Tbl 7-4 Memory Error – 7-10 Tbl 7-5 Manual Feed – 7-10 Tbl ‘7-6 Service Error -7-11 Tbl 7-7 Fuser Error -7-12 Tbl ‘7-8 Fuser Checks – 7-12 Tbl 7-9 Beam Error – 7-13 Tbl 7-10 Scanner Error -7-13 Tbl 7-11 WROM Error – 7-14 Tbl 7-12 Engine Error – 7-15 Tbl ‘7-13 Main Motor Error – 7-15 Tbl 7-14 Fan Error – 7-16 Tbl 7-15 Formatter Error – 7-16 Tbl 7-16 NVRAM Error – 7-17 Tbl 7-17 Blank Display – 7-17 Tbl 7-18 Blank (White) Page – 7-24 Tbl 7-19 Black Page -7-25 Tbl 7-20 Faded Print -7-26 Tbl 7-21 Vertical White Stripes – 7-27 Tbl 7-22 Vertical Black I.ines – 7-28 Tbl 7-23 Horizontal Black Lines – 7-28 .Vlll, Tbl 7-24 Repetitive Defects – 7-29 Tbl 7-25 Staining -7-30 Tb”l 7-26 Dropout – 7-31 Tbl 7-27 Character Voids – 7-31 Tbl 7-28 Background Scatter – 7-32 Tbl 7-29 Bottom Portion of Page Blank – 7-32 Tbl 7-30 Faulty Registration – 7-33 Tbl 7-31 Smeared Print – 7-34 Tbl 7-32 Image Skew – 7-35 Tbl 7-33 Compressed Print – 7-35 Tbl 7-34 High-Voltage System Checks – 7-41 Tbl 7-35 Causes of Paper Curl – 7-42 Tbl 8-1 Fasteners IJsed in the Printer – 8-4 Tbl 8-2 Covers and Doors (LaserJet 4L/4ML only) – 8-9 Tbl 8-3 Covers and Doors (LaserJet 4P/4MP only) – 8-11 Tbl 8-4 Internal Components 1 – 8-13 Tbl 8-5 Internal Components 2 – 8-15 Tbl 8-6 Internal Components 3 – 8-17 Tbl 8-7 DC Controller Assembly – 8-19 Tbl 8-8 Gear Train Plate Assembly – 8-20 Tbl 8-9 Paper Cassette (LaserJet 4L/4ML) -8-21 Tb[ 8-10 Paper Cassette (LaserJet 4P/4MP) -8-22 Tb~ 8-11 Pickup Assembly – 8-23 Tbl 8-12 Fuser Assembly -8-25 Tb\ 8-13 Keyboard Overlays (Laser,Jet 4P/4MP) – 8-26 ix,

Chapter Contents

Product Information Printer Features – 1-2 Identification – 1-3 Model and Serial Numbers – 1-3 Specifications – 1-4 Product Overview – 1-6 External Assembly Locations (LaserJet 4L/4ML) – 1-6 External Assembly Locations (LaserJet 4P/4MP) – 1-7 Internal Assembly Locations – 1-8 Safety Information – 1-11 Laser Safety – 1-11 Laser Statement (Finland) – 1-12 Declaration of Conformity – 1-13 Toner Safety – 1-14 MSDS Information – 1-14 By mail: – 1-14 By fax: – 1-14 Ozone Emission – 1-14 FCC Statement (Class B) – 1-15 VCCI Statement (Japan) – 1-16 Service Approach – 1-17 Exchange Program – 1-17 Ordering Parts – 1-17 Ordering Consumables – 1-17 Ordering Related Documentation – 1-18 Print Utilities – 1-19 Technical Assistance – 1-20 HP ASAP 1-800-333-1917 (U.S.) – 1-20 HP FIRST -1-20 HP FIRST, U.S. – 1-20 HP FIRST, Europe – 1-20 HP AUDIO-TIPS – 1-21 HP CompuServe Forum – 1-21 Customer Information Centers – 1-21 Customer Support Center (Assist Line) – 1-21 European Customer Support Center – 1-22 Other Areas – 1-22 ‘ Chapter 1 Contents Page 1,

CI!-mpttwcamtemrts

2 Q@a=ating Rmq@7mflmmfx ‘o Site Requirements – 2-2Operating Environment – 2-2 Printer Space Requirements – 2-3 The HP 92274A Toner Cartridge – 2-4 Storage Conditions – 2-4 ● Storing Opened Toner Cartridges – 2-5Toner Cartridge Handling Suggestions – 2-6 Refilled Toner Cartridges – 2-7 Recycling Toner Cartridges – 2-7 Media Specifications – 2-8 Media Sizes Supported – 2-9 Media Selection Guidelines – 2-10 Envelope Specifications – 2-12 Adhesive Label Specifications – 2-13 Transparency Specifications – 2-15 Storing Print Media – 2-16 Shipping Print Media – 2-16 Chapter 2 Contents Page 1, 0&@x5w’ Q3mr&?mts hs’tdktimoi and Cmfigmlmtilm Unpacking and Installation – 3-2 A. Choose the best location. – 3-2 B. Unpack the printer. – 3-2 C. Check package contents. – 3-3 D. Install the toner cartridge. – 3-3 E. Load the paper cassette. – 3-4 F. Attach the interface cable(s). – 3-4 G. Attach the power cord. – 3-5 H. Attach the Help Labels (Lase’Jet 4L/4ML only) – 3-6 I. Install Printer Drivers and Utilities (optional) – 3-7 How to Obtain Printer Drivers – 3-7 Using the Printing Software Package – 3-8 Using the Control Panel – 3-9 LaserJet 4L/4ML Control Panel Overview – 3-9 The LaserJet 4L/4ML Lights – 3-10 The LaserJet 4L/4ML Front Panel Button – 3-11 LaserJet 4P/4MP Control Panel Overview – 3-12 LaserJet 4P/4MP Control Panel Display and Lights – 3-13 Service Mode (LaserJet 4ML/4P/4MP) – 3-15 LaserJet 4ML – 3-15 LaserJet 4P/4MP – 3-15 Setting the Page Count (LaserJet 4P/4MP) -3-17 Setting the Cold Reset Default (LaserJet 4P/4MP) -3-18 Other Service Mode Items – 3-18 Printing a Self Test – 3-19 LaserJet 4L/4ML: – 3-19 LaserJet 4P/4MP: – 3-19 The LaserJet 4L Self Test Fields – 3-21 The LaserJet 4ML/4P/4MP Self Test Fields – 3-23 Continuous Self Test – 3-24 LaserJet 4L/4ML: – 3-24 LaserJet 4P/4MP: – 3-24 Engine Test – 3-25 (continued on back) Chapter 3 Contents Page 1, Resetting the Printer – 3-26 LaserJet 41J4ML: – 3-26 LaserJet 4P/4MP: – 3-26 Simple Reset – 3-26 The Menu of Resets – 3-27 The Cold Reset (LaserJet 4ML/4P/4MP) – 3-28 LaserJet 4ML: – 3-28 LaserJet 4P14MP:– 3-28 PJL Software Commands – 3-29 Contents Page 2 Chapter 3, chapter CkDntc?nts 4 Maintenancx2 Service Checkpoints – 4-2 ● Life Expectancy of Consumables – 4-3 Toner Cartridge Life – 4-4 Saving Toner with EconoMode – 4-5 a Cleaning Printer Components – 4-6Cleaning Spilled Toner – 4-7 (leafing Paper Jams – 4-8 Paper Jams in the Paper Feed Area – 4-9 Paper Jams Inside The Printer – 4-10 Paper Jams in the Paper Output Area – 4-12 Chapter 4 Contents Page 1,

Chapter Contents

5 Functional Overview Basic Printer Functions – 5-2 ● DC Controller/Power System – 5-3 Print Engine Control – 5-5 Laser and Scanner Drive – 5-5 Paper Motion Monitoring and Control – 5-5 Top Door/Toner Cartridge Microswitch (SW201) – 5-6 ‘a Engine Test MicrosWitch (SW301) -5-7 Motors – 5-7 Power System (on DC Controller PCA) – 5-8 AC Power Distribution – 5-8 DC Power Distribution – 5-8 Overcurrent/Overvoltage Protection – 5-10 Intelligent ON/OFF (LaserJet 41J4ML only) – 5-10 High Voltage Power Distribution – 5-11 Formatter System – 5-12 CPU – 5-13 Read Only Memory (ROM) -5-13 Random Access Memory (RAM) -5-13 Non-Volatile Memory (NVRAM) – 5-14 Parallel Interface – 5-14 High Speed (Yes/No) – 5-14 Advanced Functions (On/Off) – 5-14 Serial I/O (LaserJet 4P/4MP) -5-15 Pacing (Serial Modes of Operation) – 5-15 LocalTalk I/O (LaserJet 4ML/4MP) – 5-15 Control Panel – 5-16 LaserJet 4L/4ML – 5-16 LaserJet 4P/4MP – 5-16 Resolution Enhancement (REt) – 5-17 Print Density Adjustment – 5-17 a EconoMode – 5-18 Memory Management – 5-19 Memory Enhancement technology (MEt) – 5-19 Image Adapt (LaserJet 4L/4ML) – 5-20 Page Protect – 5-20 m PJL Overview – 5-21 m (continued on back) Chapter 5 Contents Page 1, Image Formation System – 5-22 Photosensitive Drum – 5-23 Drum Sensitivity – 5-24 Cleaning Stage – 5-25 Conditioning Stage – 5-26 Writing Stage – 5-27 Developing Stage – 5-29 Transferring Stage – 5-31 Fusing Stage – 5-32 Paper Feed System – 5-33 Paper Movement Overview – 5-34 Solenoids – 5-35 Photosensors – 5-35 Paper Out Sensor (PS2) – 5-35 Input Paper Sensor (PS1) – 5-36 Printing from the Paper Cassette – 5-37 Manual Feed Printing – 5-38 Small Media Rollers (LaserJet 4P/4MP) – 5-38 Paper Jam Detection – 5-39 Power-On Jams – 5-39 Pickup Jams – 5-39 Delay Jams – 5-39 Basic Sequence of Operation – 5-40 Standard Printer Operation – 5-40 General Timing Diagram – 5-41 Contents Page 2 Chapter 5,

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JRmmKmd and W@wmnm?nt Removal and Replacement Strategy – 6-2 Required Tools – 6-3 User Installable Assemblies – 6-4 Memory Upgrade (LaserJet 4L) – 6-4 Memory/Language SIMMS (LaserJet 4P/4MP) – 6-5 Cover and Doors – 6-6 Power, I/O and Memory Doors (LaserJet 41J4ML) -6-6 Printer Cover (LaserJet 4L/4ML) -6-7 Printer Cover (LaserJet 4P/4MP) -6-9 Rear Door – 6-12 Control Panel (LaserJet 4P/4MP) ~ 6-13 Left Side Assemblies – 6-15 Formatter Shield and PCA – 6-15 Gear Train Assembly – 6-17 Main Motor – 6-19 Front Assemblies – 6-20 Front Oblique Roller Assembly – 6-20 Paper Cassette Assembly – 6-21 Tray Forms Size Guide (LaserJet 4L/4ML) -6-21 Compression Springs – 6-22 Internal Assemblies – 6-23 Laser/Scanner Assembly – 6-23 Fan – 6-24 Power Switch Assembly (LaserJet 4P/4MP only) -6-25 Paper Guide/Top Oblique Roller Assembly – 6-26 Transfer Roller and Guide – 6-27 Transfer Roller Bushings – 6-28 ‘1 Beam-to-Drum Mirror Assembly – 6-29 (continued on back) Chapter 6 Contents Page 1, Rear Assemblies – 6-30 Fusing Assembly – 6-30 Fusing Assembly Components – 6-31 Pressure Plate – 6-31 Upper Fusing Assembly a (Teflon Sleeve and Heater Element) -6-32 Pressure Roller – 6-33 Delivery Assembly – 6-33 Lower Delivery Roller – 6-34 \,,~ Lower Delivery GuidelExit Sensor Flag – 6-35 m Connector Assembly (Fuser Entrance Guide) – 6-36 Upper Output Roller Assembly – 6-37 Lower Output Rollers – 6-38 Bottom Assemblies – 6-39 DC Controller Assembly – 6-39 Pickup Solenoid (SL2) – 6-41 DC Controller Fuses – 6-42 High Voltage Connector Assembly – 6-42 DC Controller PCA – 6-43 Pickup Feed D-Roller – 6-46 Pickup Assembly – 6-47 Feeder Guide Assembly and High Voltage Shield – 6-49 Small Media Roller Assembly (LaserJet 4P/4MP) -6-50 Static Eliminator Strip Assembly – 6-51 Toner Cartridge Lever Assembly – 6-52 Top Door Switch (Plunger Assembly) – 6-53 DC Controller/Scanner Connector Assembly -6-54 PS1 Input Paper Sensor Arm – 6-56 0. ., Contents Page 2 Chapter 6, ... -’ TmlldMeshmtintg Troubleshooting Flowchart – 7-2 Paper Path and Components – 7-4 DC Controller Diagram – 7-5 Printer Error Troubleshooting – 7-6 LaserJet 4L/4ML: – 7-6 LaserJet 4P/4MP: – 7-6 Priority of Errors – 7-7 Recoverable Errors – 7-7 Service Errors – 7-11 LaserJet 4L/4ML – 7-11 LaserJet 4P/4MP – 7-11 Clearable Warnings (LaserJet 4P/4MP) – 7-18 Image Formation Troubleshooting – 7-19 Engine Test – 7-36 Engine Test Button Location – 7-36 Printing an Engine Test - LaserJet 4L/4ML – 7-36 Printing an Engine Test - LaserJet 4P/4MP – 7-37 Half Self Test Functional Check – 7-39 Drum Rotation Functional Check – 7-40 High-Voltage Power Supply Check – 7-41 Paper Curl – 7-42 Adjustment Procedures – 7-43 Leading Edge Adjustment – 7-43 Beam-to-Drum Mirror Adjustment – 7-44 Troubleshooting Tools – 7-46 Repetitive Image Defect Ruler – 7-46 Main Wiring Diagram – 7-47 Chapter 7 Contents Page 1,

Chapter Contents

$ Parts and Diagrams a How to Use the Part Lists and Diagrams – 8-2Orderhw Parts – 8-2 Orderin~ Consumables – 8-3 Common Hardware – 8-4 ,’ Accessories and Supplies -8-5 m Assembly Locations -8-7 Covers and Doors (LaserJet 4L/4ML) -8-8 Covers and Doors (LaserJet 4P/4MP) -8-10 Internal Components 1 – 8-12 Internal Components 2 – 8-14 Internal Components 3-8-16 DC Controller Assembly – 8-18 Gear Train Plate Assembly -8-20 Paper Cassette (LaserJet 4L/4ML) – 8-21 Paper Cassette (LaserJet 4P/4MP) – 8-22 Pickup Assembly – 8-23 Fuser Assembly -8-24 Keyboard Overlay (LaserJet 4P/4MP) – 8-26 Chapter 8 Contents Page 1, AppendixA Parts Index, Appendk B 170IMorrnation, Product Itiormation, Product Information Printer Features

Printer Features

Features I LaserJet 4L I LsaarJet 4ML(C2003A) (C2015A) Print Speed I 4ppm Text &Graphics Resolution 300 dpi; @JS 300 dpi; plus 600 dpi; plus 600dpi; plus Res Enhancement Res Enhancement Res Enhancement Res Enhancement technology (REt) technology (REt) technology (REt) technology (REt) Printer Language Stsndard Enhanced PCL 5 Enhanced PCL 5 Enhanced PCL 5 Enhanced PCL 5 PostScript Level 2 PostScript Level 2 Optionat None None PS L2 (with SIMM None +4 Mb opt memory)’ Monthly Usage (pages) I Upto6000 UP tO 8000 up to 8000 UPto 8000 Output Tray Capacity I 50 50 I 45 PCL, 35 PS * o =-l=- Standard Interfaces Parallel (13-tronics) Parallel (8i-tronics) Setial (9 pin) Serial (9 pin) LocalTalk Parallel (8i-tronics) Parallel (!3-tronics) LocalTalk Power Control 1 bteligentC)n/Ofl Intelligent On/Ofl I Power switch lF’owerswitch I EconoMode (toner saving) Yes Min. Paper Size3x6.75 inch (using flat paper path) (76 x 171 mm)

See“Accessories& Supplies”in Cha ter 8 for optionproductnumbers.

2 Printermemoryis optimizedwithMemoryEnhancementTechnology(MEt). 1-2, Product Information Identification

Identification Model and Serial Numbers

The model number and serial numbers are listed on identification labels located on the rear of the printer. The model number is alphanumeric, such as C2003A for the HP LaserJet 4L. The serial number contains information about the Country of Origin, the Revision Level, the Production Code, and production number of the printer. The rear labels also contain power rating and regulatory information as shown in Figure 1-1.

I I

Figure 1-1 Sample Model and Serial Number Labels 1-3, Product Information Specifications

Specifications

Table 1-1 Printer Dimensions LaserJet 4L/4ML LaserJet 4P/4MP Dimension (C2003A/C2015A) (C2005A/C2040A) ● Width 36 cm (14,25 in.) 40 cm (15.75 in.) Depth 137 cm (14.5 in.) 139 cm (15.5 in.) , 1 Heiaht 116.5 cm (6.5 in.) 118 cm (7 in.) I Table 1-2 Performance Specifications

I CATEGORY I SPECIFICATION I

Print Speed * Up to 4 pages per minute Monthly Usage (Duty Cycle) Up to 8000 pages Life Expectancy of toner cartridge** Approximately 3000 pages I First Print lApproximately 34 seconds I *Actual speed depends on data complexity and software handling efficiency. **Toner Cartridge life can be extended by using EconoMocle. 1-4, Product Information Specifications Table 1-4 Electrical Specifications WATTS (typical) VOLTS FREQ AMPS* 4L14ML I 4P14MP 120 Vact10% 50/60 Hzk2Hz 36 100 Vac ? 10% 50/60 Hz? 2 Hz 220 Vac f 1O% 50/60 Hz+ 2 tiz ,8 240Vac k 10% 50/60 Hzk2Hz “ *Operating current requirements. Table 1-3 Environmental Specifications Operating Environment ‘temperature: 10° C to 32.5° C (50° F to 90.5° F) Iumidity: 20-80% (no condensation) Storage Environment ‘temperature: -20° to 60° C (-4° to 140”F) (not including toner cartridge) Iumidity: 15-90% (no condensation) Acoustic Emissions 4L 4P 4ML 4MP Operation position (per ISO 9296, DIN 45635,T.1 9): Printing LPA dB(A) <48 <49 <51 <49 Standby LPA dB(A) <22 <33 <22 <31 Bystander 1m (per ISO 7779, DIN 45635,T.1 9): Printing LPA dB(A) <45 <46 <47 <46 Standby LPA dB(A) <22 <30 <22 <29 Sound Power (per ISO 9296): Printing LPA dB(A) <5.9 <6.0 <6.1 <6.0 Standby LPA dB(A) <3.5 <4.4 <3.6 <4,4 1-5, Product Information Product Overview

Product Overview

External Assembly Locations (LaserJet 4L/4ML) Figure 1-2 External Assembly Locations, Laserdef 4L/4ML 1-6, Product Information Product Overview

External Assembly Locations (LaserJet 4P/4MP)

1-7, Product Information Product Overview

Internal Assembly Locations

Figure 1.4 Internal Assembly Locations (all printers) 1, Face-Down Output Rollers 10, Pickup Feed D-Roller 2. Upper Fusing Assembly 11. Transfer Roller Assembly 3. Laser/Scanner Assembly 12, Photosensitive Drum 4. Primary Charging Roller 13. DC Controller PCA 5. Beam-to-Drum Mirror 14. Paper Cassette 6. Developing Cylinder 15. Fusing Pressure Roller 7. Toner Cartridge 16. Face-up Delivery Roller 8. Registration Roller 17. Face-Up/Face-Down Deflector 9. Oblique Rollers 1-8, Product Information Product Overview Fim.me 1-5 shows the location of assemblies visible from the ton of — th; LaserJet 4L printer with the printer cover removed. ‘ ~lgure 1-5 LaserJet 4L Internal Assembly Locations 1. Transfer Roller 8. Fusing Assembly 2. Paper Guide/Top Oblique Roller 9. Lower Output Rollers (Face-Down) 3. Front Oblique Roller 10. Upper Output Rollers (Face-Down) 4, Switch Actuator 11. Fan (FM1) 5. Formatter PCA 12. Beam-to-Drum Mirror m 6. Main Motor 13. Laser/Scanner Assembly 7. Gear Train Assembly ● 1-9, Product Information Product Overview Figure 1-6 shows the location of assemblies visible from the top of the LaserJet 4P printer with the printer cover removed. Figure 1-6 LaserJet 4P Internal Assembly Locations 1. Transfer Roller 9. Fusing Assembly 2. Paper Guideflop Oblique Roller 10. Lower Output Rollers (Face-Down) 3. Front Oblique Roller 11. Upper Output Rollers (Face-Down) 4. Cartridge Bracket 12. Fan (FM1) 5. Formatter PCA 13. Power Switch (not shown) 6. SIMM Slots (3) 14, Beam-to-Drum Mirror 7, Main Motor 15, Laser/Scanner Assembly 8. Gear Train Assembly 1-1o, Product Information Safety Information

Safety Information Laser Safety

The Center for Devices and Radiological Health (CDRH) of the U.S. Food and Drug Administration implemented regulations for laser products manufactured since August 1, 1976. Compliance is mandatory for products marketed in the United States. This printer is certified as a “Class 1“ laser product under the U.S. Department of Health and Human Services (DHHS) Radiation Performance Standard according to the Radiation Control for Health and Safety Act of 1968. Since radiation emitted inside this printer is completely confined within protective housings and external covers, the laser beam cannot escape during any phase of normal user operation. Never operate or service the printer with the protective cover removed from the Laser/Scanner Assembly. The reflected beam, although invisible, can damage your eyes. 1-11, Product Information Safety Information

Laser Statement (Finland)

The following applies to printer operation and servicing in Finland.

LASERTURVALLISUUS

LUOKAN 1 LASERLAITE KLASS 1 LASER APPARAT HPLaserJet(s)4L,4ML,4P &. 4MP Iaserkirjoitin on kayttajan kannalta turvallinen luokan 1 laeerlaite. Normaalissa kaytossa kirjoittimen suojakotelointi estaa lasersateen paasyn laitteen ulkopuolelle. Kirjoittimen on hyvaksynyt Suomessa laserturvallisuuden osalta Stikotarkastuskeskus. Laitteen turvallisuusluokka on maaritetty valtioneuvoston paatoksen N:o 472/1985 ja standardin EN 60825 (1991) mukaisesti. VAROITUS ! Laitteenkayttaminenmuullakuinkayttoohjeessamainitullatavalla saattaaaltistaakayttajanturvallisuusluokan1 ylittavalle nakymattomalle lasersateilylle. VARNING ! Omapparatenanvandspa annatsattw i bruksanvisning specificeratsk, ananvandarenutsattasfor osynliglaserstr~lnings, omoverskrider griinsenfor laserklass1. HUOLTOHP LaserJet(s)4L, 4ML,4P & 4MP-kirjoittimensisalliiei olekayttajan huollettavissaoleviakohteita.Laitteensaaavataja huoltaaainoastaansen huoltamiseenkoulutettuhenkilo.Tallaiseksihuoltotoimenpiteekseii katsota variainekasetinvaihtamista,paperiradanpuhdistustatai muitakayttajiin kasikirjassalueteltuja,kayttajantehtavaksitarkoitettujayllapitotoimiaj,otka voidaansuorittaailmanerikoistyokaluja. VARO ! Mikalikirjoittimensuojakoteloavataan,oletalttiinanakymattomalle lasersateilyllelaitteenollessatoiminnassa.~a katsosateeseen. VARNING ! Omlaserprinternsskyddsholjeoppnasd5.apparatenar i fanktion, utsattasanvandarenfor osynliglaserstr~lningB. etraktaej str?alen. Tiedotlaitteessakaytettavanlaserdiodinsateilyominaisuuksista: Aallonpituus777-795nm Teho5 mW Luokan3B laser 1-12, Product Information Safety Information

Declaration of Conformity

● According to ISO/IEC Guide 22 and EN 45014: Manufacturer’s Name: Hewlett-Packard Company ● Manufacturer’s Address: 11311 Chinden Boulevard Boise, Idaho 83714-1021, USA declares, that the product Product Name(s): LaserJet 4L/4ML/4P/4MP Model Number(s): C2003A, C2015A, C2005A, C2040A Product Options: All conforms to the following Product Specifications: Safet~ EN 60950:1988+ A1,A2 IEC 825:1984 + A1:1990 laser class 1 EMC: CISPR-22:1985 / EN 55022:1988 class Bl) EN 50082-1:1992 IEC 801-2:1991/ prEN55024-2:1992 - 3kV CD, 8 kV AD IEC 801-3:1984/ prEN55024-3:1991 - 3V/m IEC 801-4:1988/ prEN55024-4: 1992-1 kV Power lines Supplementary Information: The product herewith complies with the requirements of the Low Voltage Directive 73/23/EEC and the EMC Directive 89/336/EEC. a 1) The product was tested in a typical configuration with Hewlett-Packard Personal Computer and Test Systems. Office of Quality Manager ● Boise, Idaho USAJune 15, 1993 European Contact: Your Local Hewlett-Packard Sales and Service OffIce or Hewlett-Packard GmbH, Department ZQ / Standards Europe, Herrenberger Strae 130, D-7030 Bblingen (FAX + 49-7031-14-3143) o 1-13, Product Information Safety Information

Toner Safety

Note In case of toner spills, skin and clothing are best cleaned by removing as much toner as possible ● with a dry tissue, then washing with cold water. Hot water causes toner to permanently set into clothing. MSDS Information A Material Safety Data Sheet (MSDS) for toner or any other chemical used in the printer is available through Hewlett-Packard’s Customer Information Center by either mail or fax. By mail: To obtain an MSDS for the HP 92274A toner cartridges through the mail, call the Customer Information Center (CIC) at 1-800-752-0900 between 6 A.M. and 5 P.M. Pacific Standard Time. By fax To obtain an MSDS for the HP 92274A toner cartridges by fax, call HP ASAP (Automated Support Access Program) at 1-800-333-1917 and follow the instructions for using the HP FIRST fax service. Note See “Technical Assistance” later in this chapter for more information on the HP FIRST service.

Ozone Emission

These printers do not use high voltage corona wires in the electrophotographic process, and therefore generate no measurable ozone gas (03). The printers instead use charging rollers in the toner cartridge and in the print engine. ● 1-14, Product Information FCC Statement (Class B)

FCC Statement (Class B)

Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause hmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: ● Reorient or relocate the receiving antenna. ● Increase the separation between the equipment and the receiver. ● Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. ● Consult the dealer or an experienced radio/TV technician for help. Any changes or modifications not expressly approved by Hewlett-Packard could void the user’s authority to operate this equipment. Note Use of a shielded interface cable is required to comply within the Class B limits in Part 15 of FCC rules. 1-15, Product Information VCCI Statement (Japan)

VCCI Statement (Japan)

The VCCI statement below is required in Japan. It is similar to the FCC regulatory statement. - 1-16, Product Information Service Approach ●

Service Approach

● Repair of the printer normally begins with use of the printer’s internal diagnostics in conjunction with the troubleshooting procedures in Chapter 7. Once a faulty part is located, repair is accomplished generally by assembly-level replacement of Field e Replaceable Units (FRUS). Some mechanical parts maybe repaired at the sub-assembly. PCA component replacement is not supported by HP. Part numbers for all FRUS are located in Chapter 8 of this manual.

Exchange Program

HP offers remanufactured assemblies for some selected parts. These are identified in Chapter 8 and can be ordered through HP’s Parts Direct Ordering, or Parts Center Europe (PCE).

Ordering Parts

Field replaceable part numbers are found in Chapter 8 of this manual. Replacement parts may be ordered from HP’s Parts Direct Ordering, or Parts Center Europe (PCE). Adresses and phone numbers for both organizations are also found in Chapter 8.

Ordering Consumables

Consumables may be ordered directly from Hewlett-Packard. The phone numbers for ordering consumables are found in Chapter 8. 1-17, Product Information Service Approach

Ordering Related Documentation

Table 1-5 shows where to order related documentation. Phone numbers for the various sources are: . PDO (Parts Direct Ordering) 1-S00-227-8164 (U.S. only) . PCE (Parts Center Europe) (49 7031) 14-2253. e HP’s Distribution Center (HPD) 303-353-7650 (U.S. Ody), Product Information Service Approach Table 1-5 Relaiecl Documentation DESCRIPTION PART NUMBER PDO I PCE HPD

I

HP LaserJet Family Quick Reference 5961-0531xxService Guide HP LaserJet 4L User’s Manuall C2003-90901 xx HP LaserJet 4ML User!s Manuali C2015-90901 xx HP LaserJet 4P User’s Manualf C2005-90943 xx HP LaserJet 4MP User% Manual’ C2040-90912 xx HP PCL5 Printer Language Technics/ 5961-0601 xx Reference Information Package HP LaserJet Printer Family Paper 5002-1801 x Specifications Guide HP LaserJet 4L Software Solutions Pkg, f C2003-60122 x HP LaserJet 4ML Windows Solutions Pkg. 1 C201 5-60101 x HP LaserJet 4ML Macintosh Solutions Pkg.1 C201 5-60113 x HP LaserJet 4P Software Packl C2OO5-6O1O7 ; ~ HP LaserJet 4MP Software Packl’2 C2040-601011xShiu~ed with Drinter. (English version Dart number is shown Other tra;~lations a;e available -see your loc~l HI Sales Office.) z. Includes DOS. Windows and Macintosh solutions. Print Utilities HP provides several utilities for enhancing use of the LaserJet printers in DOS, MS Windows, and Macintosh environments. More information on specific utilities is included with each of the software packs listed in Table 1-5. 1-19, Product Information Technical Assistance

Technical Assistance HP ASAP 1-800-333-1917 (U. S.)

HP ASAP (Automated Support Access Program) provides free technical support information 24 hours a day, 7 days a week. The ASAP system includes HP FIRST and HP AUDIO-TIPS, both explained below. The ASAP service requires a touch-tone phone.

HP FIRST

HP FIRST (Fax Information Retrieval Support Technology) is a phone-in fax service providing technical information for HP LaserJet users as well as service personnel. Receiving a fax requires a group 3 facsimile machine or fax card. Service-related information includes: Service notes (HP Authorized dealers). Application notes. Product Data Sheets. Material Safety Data Sheets (MSDS). Typeface and accessory information. Printer support software information. Toner information. Driver request form and Software Matrix. HP FIRST, U.S. Call the HP ASAP system (1-800-333-1917) and follow the voice prompts to enter HP FIRST. HP FIRST, Europe Call HP FIRST at one of the following numbers: U. K., 0800-96-02-71 Netherlands, 06-0222420 Belgium (Dutch), 078-111906 Germany, 0130-810061 Switzerland (German), 155-1527 Austria, 0660-8128 For English service outside the above countries, (31) 20-681-5792 1-20, Product Information Technical Assistance HP AUDIO-TIPS HP AUDIO-TIPS, available within HP ASAP, is an interactive voice response system providing pre-recorded answers to the a questions most frequently asked by HP LaserJet printer users. Helpful “System Maps” to the HP AUDIO-TIPS recordings are available by fax through HP FIRST. ● HP CompuServe Forum CompuServe members can download a variety of support materials including product data sheets, software application notes, and printer drivers for many popular software applications. Members may also post and reply to questions in an interactive format. To access the HP Forum, type GO HPPER at any prompt. For more information, or to join CompuServe, call 1-800-524-3388.

Customer Information Centers

For further technical assistance, service-authorized HP and dealer service personnel can contact the nearest Hewlett-Packard Customer Information Center, 1-800-752-0900 in North America.

Customer Support Center (Assist Line)

The HP Customer Support Center, (208-323-2551) is available to answer technical questions regarding setup, configuration, installation and operation of HP printers in the PC and Macintosh environments. The CSC Assist Line is available weekdays from 7AM to 6 PM Mountain Time (Wednesdays until 4 PM). Questions relating to operating systems such as MS-DOS and UNIX, your network conjuration, or network operating system a cannot be answered by the Center and should be referred to your authorized reseller. 1-21, Product Information Technical Assistance

European Customer Support Center

The HP European Customer Support Center, located in Amsterdam, Holland, is open from 8:30 am to 6:00 pm central European time (Wednesdays until 4:00 pm). Multilingual customer ● support representatives can answer technical questions similar to the U.S. CSC, described on the previous page. This service is available at no charge for a period equivalent to the original HP hardware warranty period. ● Each time you call the HP European Customer Support Center, you will be required to provide the printer’s serial number and original date of purchase. To receive a fax listing the supported languages on a countries’ phone number, call HP FIRST (refer to “HP FIRST,” earlier in this section). You can also call the nearest HP sales and service office to obtain the telephone number for the Center. The Center features automated call-routing technology, so you will receive faster service if calling from a touchtone phone or tone dialer.

Other Areas

Outside of North America and Europe, contact your local HP sales office for assistance in obtaining technical support. a ● ● 1-22, =.~ ● Operating Requirements, Operating Requirements SiteRequirements

Site Requirements Operating Environment

The environmental specifications listed in the “Specifications” section of Chapter 1 must be maintained to ensure the proper operation of this printer. Consider the following points before installing the printer: Install in a well-ventilated, dust-free area. (Excess dust or smoke will contaminate the printer’s Beam-to-Drum mirror, affecting print quality. ) Install on a hard, flat and continuous surface, with all four printer feet level. Do not install on carpet or other soft surfaces. Ensure adequate power supply circuitry. Printer current requirements can be found under “Specifications,” in Chapter 1. Lighting Flicker: In an effort to reduce energy consumption, the fuser is turned on only when needed during printing. During standby mode, the fuser is not kept warm. When the printer is installed in a home, the instant-on fuser may cause some house lights to flicker when printing. This phenomenon is seen in many instant-on products, such as copiers, and will NOT affect printing, nor will it harm the electrical system in any way. To reduce a flicker effect, plug the printer into a different outlet that may be on a separate circuit, or try fluorescent lighting. If possible, add to the room’s natural lighting. (Surge suppressers will not prevent flickering lights.) Install where there is stable temperature and humidity, with no abrupt changes (away from water sources, humidifiers, air conditioners, refrigerators, or other major appliances). Install away from direct sunlight, open flames, or ammonia fumes. If the printer is placed near a window, make sure the window has a curtain or blind to block any direct sunlight. Install with enough space around the printer for proper access and ventilation (see Figure 2-l). 2-2, Operating Requirements Site Requirements Printer Space Requirements ...A. ;B~.. ‘ c,;..,...m~ “~‘1 ~, -””-”? \ ‘i \ \\ ‘,‘,;,

II

,- ,.’ . ,- - *j F -“==4 F.-. m - . Hgwe z-l wmer space ~equ~remenls -i-able 2-1 Printer Operating Dimensions Operating I LaserJet 4L/4MLDimensions I LaserJet 4P/4MP A (l-m))) I 14 inches (35.5cm) I 15 inches (38 cm) I El (Dqm) 14.5 inches (37 cm) 15.5 inches (39 cm) C (Width) 14.25 inches (36 cm) 15,75 inches (40 cm) D (Rear Dow) I 2 inches (5 cm) I 2 inches (5 cm) I E (Height - Top 13 inches (33 cm) 14 inches (35 cm) Door Cqoxw)) I I 2-3, Operating Requirements The HP 92274A Toner Cartridge

The HP 92274A Toner Cartridge

Toner cartridges contain components which are sensitive to light, temperature, and humidity. Follow the recommendations in this section to ensure the highest quality and longest life of HP toner cartridges. Table 2-2 Toner Cartridge Environmental Conditions11ICATEGORY I TEMPERATURE I HUMIDITY I Operating 10° to 32,Y c 35 tO85% RH (50° to 90.5° F) Storage -20° to 40° c 15 to 90% RH (-4° to 104° F)

Storage Conditions

The toner cartridge is affected by its environment. Packaging protects the toner cartridge from light and increases its storage life. It is important to store the cartridge in its original packaging until the cartridge is ready to be installed in the printer. When storing the toner cartridge in a warehouse or work area, make sure the storage place meets the conditions specified in Table 2-2. Note The expiration date of the toner cartridge is stamped on the cartridge box. This date allows for up to 2V2 years after manufacture. 2-4, Operating Requirements The 1+ 92274A Toner Cartridge Storing Opened Toner Cartridges Because the cartridge does not have a shutter to cover the laser ● beam access slot, it should be kept inside the printer until empty.Toner cartridges which have had the toner sealing tape removed are also more vulnerable to environmental extremes (such as high humidity). ● If the toner cartridge must be removed from the printer, alwaysstore the cartridge: Inside the protective bag in which it was originally packaged. In a dark cabinet, away from direct sunlight. Correct side up and in a horizontal position (not standing on end). In a temperature between 10° and 35° C (50° -95° F). Away from ammonia or other organic solvent fumes. CAUTION Never ship the printer with a toner cartridge installed. Excessive vibration during shipping can cause toner to leak, contaminating the printer. Never expose the toner cartridge to direct sunlight, or to room light for more than a few minutes. Bright light and direct sunlight can permanently damage a toner cartridge. 2-5, Operating Requirements The HP 92274A Toner Cartridge

Toner Cartridge Handling Suggestions

● Before installing a cartridge, distribute the toner evenly by rotating the cartridge back and forth five to six times (see Figure 2-2). Repeat this action when toner begins to run low. ● Figure 2-2 Distributing Toner ● Do not touch the sutiace of the photosensitive drum in the cartridge. Protect the drum from light and contamination. ● Do not disassemble or refill a toner cartridge, ● Do not expose the cartridge to unnecessary vibrations or shock. ● Do not expose the photosensitive drum to strong light. White areas on the page may indicate that the drum has been exposed to light for too long. If white areas appear, stop the printer and wait a few minutes. This process should eliminate most ● defective images, If not, the toner cartridge maybe placed in a dark environment for an extended period of time, which may restore some life to the drum. ● Never manually rotate the drum, especially in the reverse ● direction; internal damage and toner spills may result. 2-6, Operating Requirements The W 92274.4 Toner Cartridge

Refilled Toner Cartridges

While Hewlett-Packard does not prohibit the use of refilled toner cartridges during the warranty period or while under a maintenance contract, we do not recommend their use. The reasons for this are: Hewlett-Packard has no control or process to ensure that a refilled toner cartridge functions at the high level of reliability of a new HP LaserJet toner cartridge. Hewlett-Packard also cannot predict what the long term reliability effect on the printer is from using different toner formulations found in refilled cartridges. Hewlett-Packard has no control over the actual print quality of a refilled toner cartridge. The print quality of HP LaserJet toner cartridges influences the customer’s perception of the printer. Re~airs resultimz from the use of refilled toner cartridges are no{ covered und& the HP warranty or maintenance contract.

Recycling Toner Cartridges

In order to reduce the amount of plastics and other wastes entering our landfllls, Hewlett-Packard has established a program for recycling used toner cartridges. Parts that do not wear are re-used in manufacture of new cartridges. Plastic and other materials are recycled. HP pays the shipping costs. In addition, a one dollar donation is shared by the Nature Conservancy and the National Wildlife Federation for each cartridge returned under this program. To join this recycling effort, follow the instructions included inside each toner cartridge box. 2-7, Operating Requirements Media Specifications

Media Specifications

Several types of print media can be used with HP LaserJet printers, provided the media specifications are met, Using media that does not meet the specifications listed in this section may increase the incidence of paper jams, cause premature printer wear, and contribute to repair costs. Note More detailed media specifications are available in the HP LaserJet Printer Family Paper Specification Guide, part number 5002-1801. To order additional copies, refer to “Ordering Related Documentation” in Chapter 1. It is possible that print media can meet all of the general specifications listed and still not print satisfactorily because of the printing environment or other variables over which Hewlett-Packard has no control. Hewlett-Packard neither warrants nor recommends the use of any particular media brand. Properties are subject to change by manufacturers and HP has no control over such changes. The operator should test particular media prior to large purchases. All media should be stable at the 392° F / 200° C temperatures encountered in the printer’s fusing process. CAUTION Use ordy media recommended for use in laser printers. Printer damage resulting from use of incompatible media will not be covered by HP warranty or service agreements. 2-8, Operating Requirements Media Specificatkms

Media Sizes Supported

The following media sizes are supported by the printer’s paper cassette and manual feed slot. -i-able2-3 Supported MediaS3zes LaserJet 4L/4ML LaserJet 4P/4MP Sizes Universal Manual - Cassette Feed Minimum size:* 73x7.5 in. (76x 190 mm) Y r 3x5in. (76x 127mm) r Letter, 8.5 x 11 in. (216x279 mm) -x1-xxxLegal, 8.5 x 14 in. (216x 356 mm) X1X += xxIExec, 7.25 x 10.5 in. (184x 267 mm) IXIXX1X A4, 210 x 297 mm (8,27 x 11.69 in.) xxxxEnvelopes: Com-10, 4.1 x9.5 in. (105 x241 mm) r Monarch, 3.87 x 7.5 in. (98x 191 mm) r DL, 110 x220 mm (4.3 x 8.6 in,) r C5, 162x 229 mm (6.4x9in.) r “ Use the “flat paper path” only (manual feed and rear outpu 2-9, Operating Requirements Media Specifications

Media Selection Guidelines

To achieve the best possible print quality and avoid paper jams, follow these guidelines for selecting paper: e Use only high quality, copier grade paper. Avoid paper with embossed lettering, perforations, or texture that is too smooth or too rough. ● Colored paper should be of the same high quality as white photocopy paper. The pigments must withstand the printer’s fusing temperature of 392° F (200° C) for 0.1 second without deterioration. Do not use paper with a colored coating that was added after the paper was produced. Pre-printed forms must be printed with non-flammable, heat-resistant inks that do not melt, vaporize, or release hazardous emissions when subject to the printer’s approximately 392° F (200° C) fusing temperature for 0.1 second. Always test a small sample of a new print media before purchasing large quantities. Give a copy of the table on the next page to your paper vendor to ensure that the paper you purchase meets the specifications for this printer. More detailed specifications are in the HP LaserJet Printer Family Paper Specification Guide, HP Part No. 5002-1801. (See “Ordering Related Documentation” in Chapter 1.) 2-1o, Operating Requirements Media Specifications ● Basis Weight Paper Cassette: 16 to 28 pound (60 to 105 g/m2).Manual Feed Slot: 16 to 36 pound (60 to 135 g/m2).* Finishing Precision Cut sheet to within 0.3 inch (0.8 mm) of nominal, 0.20° square. ● Furnish (Composition) 100% chemical wood pulp and/or cotton fiber. Grain Long grain. Moisture Content 4,7 *I% by weight. Packaging Polylaminated moisture proof ream wrap. Smoothness 100 to 250 (Sheffield)* * LaserJet 4P/4MP only Heavier paper stock, in the range of 36 to 42 pound (135 to 158 gid) may be used, but must use the “flat paper path” (manual feed, rear output) and have a Sheffield smoothness rating not greater than 180. ~~~~~ The “flat paper patlf (manual feed slot and rear face-up delivery door) is recommended for envelopes, overhead transparencies, and labels. 2-11, Operating Requirements Media Specifications

Envelope Specifications

Choose envelopes that are well-constructed. They should lay flat and be sharply creased. They should not be wrinkled, nicked, or otherwise damaged. Envelopes with a peel-off adhesive strip, or more than one fold-over flap to seal, must use adhesives compatible with the heat and pressure of the printer’s fusing process. When printing envelopes, always use the “flat paper path” ~manual feed siot and the rear face-up delivery door). CAUTION To prevent severe printer damage, do not use envelopes having windows, clasps, snaps, or synthetic materials. TaMe 2-5 Envelope Specifications Paper Paper used for envelope construction must meet the requirements in the table under “Media Selection Guidelines.” Basis Weight 20 to 24 pound (75 to 90 g/m2), single thickness Caliper 3.3 to 5.5 roils (0.084 to 0.14 mm), single thickness I Curl (Pre-printed) Envelopes must lay flat with no more than 0.2 in. (5 mm) curl across the entire surface. I Finishing Envelopes must not have any adhesive exposed to the printer. They must be folded accurately, within f 0.04” (1 mm). There must be no more than two thicknesses of paper anywhere along the leading edge. All folds must be well scored and sharply creased, and construction must be tight (not baggy). Envelopes must not be stuck together with excess seam sum. Furnish (Composition) 1100% chemical wood pulp and/or cotton fiber. Fusing Compatibility Must not scorch, melt, offset, or release hazardous emissions when heated to 392° F (20V C) for 0.1 second, I Grain Long grain. Moisture Content 4.7 +1% bv weiaht. Smoothness 1100 to 250 (Sheffield) 2-12, Operating Requirements Media Specifications

Adhesive Label Specifications

Use the following guidelines when selecting labels: The top sheet (printing surface) must be of copier quality and provide good toner adhesion. The carrier sheet (backing sheet) must be compatible with the temperatures and pressure of the fusing process, and must be coated for easy release of the top sheet. The adhesive must be stable at the 392° F (200° C) temperatures encountered for 0.1 second in the printer’s fusing process, and must not produce emissions that exceed exposure levels or threshold limits established by OSHA and other safety agencies. Adhesives must not come into direct contact with any part of the printer. Labels must be arranged on the carrier sheet so that any exposed spaces run lengthwise down the sheet. Using label stock with spaces between the horizontal rows of labels can often result in labels peeling off during printing, causing serious jamming and possible printer damage. wide selection of suitable labels is available through Hewlett-Packard. A list of available sizes is in the H“P LaserJet Printer Family Paper Specification Guide, HP Part No. 5002-1801. See Chapter 1 for ordering information, or contact your local authorized HP dealer. CAUTION - Do not attempt to print on label sheets after any of the labels have been removed from the sheet. Damage to the printer may result. 2-13, Operating Requirements Media Specifications Adhesive Must not be on any external surfaces of the label before, during or after printing. Label construction and die-cutting must not allow labels to peel off during transport, printing, or fusing. Caliper Must not exceed 0.007 in. (0,1 9 mm) Curl In ream: flat within 0,2 in, (5 mm) Finishing Precision Cut sheet within 0.031 in. (0.79 mm) of nominal and 0.20° square. Fusing Compatibility All adhesives, carrier sheets, top sheets, and other materials used in label construction must be compatible with the heat and pressure of the fusing iprocess, Materials must not discolor, melt, offset, or release hazardous emissions when heated to 392° F (20V C) for 0.1 second, Packaging Moisture proof wrap to preserve properties. — The “flat paper path” (manual feed slot and rear face-up delivery door) is recommended for printing adhesive labels. 2-14,

Transparency Specifications

Overhead transparencies used in HP LaserJet printers must be able to withstand the 392° F (200° C) temperatures encountered in the printer’s fusing process for 0.1 second. Suitable transparency film is available through Hewlett-Packard. Refer to Chapter 3 of the HP LaserJet Printer Family Paper Specification Guide, HP Part No. 5002-1801 for details. Caliper 13.9 to 4.3 roils (0.100 to 0.110 mm) Cutting Angle 90° * 0.2° Finishing precision Cut sheet to within 0.03 in. (0.8 mm) of nominal and t 0.2° of square. Fusing Compatibility Overhead transparency material must be compatible with the heat and pressure of the fusing process. Materials must not discolor, melt, offset material, or release hazardous emissions when heated to 392° F (200° C) for 0,1 second. The “flat paper pat~ (manual feed slot and rear face-up delivery door) is recommended for printing transparencies. 2-15, Operating Requirements Media Specifications

Storing Print Media

Follow these guidelines when stacking and storing print media: Store paper in its ream wrapper until ready to use. DO NOT store cartons or reams directly on the floo~ place cartons on a pallet or on shelves. DO NOT store individual reams in a manner that causes them to curl or warp along the edges. Re-wrap partially used packages of media before storing. DO NOT stack more than six cartons on top of each other. Stack each carton squarely on top of the one underneath. Stack each carton upright. DO NOT place anything on top of media, regardless of whether the paper is packaged or unpackaged. Store envelopes in a protective box to avoid damaging the envelope edges. Keep stored media away from temperature and humidity extremes. DO NOT store printed documents in vinyl folders (which may contain plasticizers) or expose the documents to petroleum based solvents.

Shipping Print Media

When shipping print media through different environments, plastic wrap all cartons on the shipping pallet. When shipping media across bodies of water, wrap individual cartons as well. Packaging must protect the media from physical damage. 2-16, Installation and Configuration, Installation and Configuration Unpacking and Installation

Unpacking and Installation

Before unpacking the printer, inspect the shipping container for signs of physical damage. Since a damaged shipping box is an indication of improper handling during shipping, the printer may also be damaged.

Note If the shipping container has any sign of

damage, unpack and power the printer ON with the carrier’s agent present. If the printer appears damaged or fails self test, do not accept it.

A. Choose the best location.

Verify that the printer location meets all requirements listed in Chapter 2.

B. Unpack the printer.

1. Remove the power cord, the manuals, and the toner package. 2. Remove the printer from its box. 3. Remove the outer packing material from the printer. 4. Open the printer top door by pressing the door release button on the right side of the printer (see Chapter 1, Figure 1-2 or 1-3 for location). 5. Pull out the paper cassette. 6. Remove the packing spacers from the inside of printer (2 on the Transfer Roller) and from the paper cassette (2).3-2, Installation and Configuration Wy3acking and installation

C. Check package contents. Nate If any of the package contents are missing or

damaged, contact your HP dealer immediately. The package should include the following: ● Printer.Power cord.Software Solutions package. ● User’s Manual. ● Toner cartridge. Note Interface cables are sold separately. Refer to Chapter 8 for part numbers.

D. Install the toner cartridge.

1. Press the top door release button to open its top door. 2. Remove toner cartridge from its box and cut it open. Save the packing materials for possible cartridge storage. 3. Shake the cartridge vigorously to distribute the toner evenly inside the cartridge (see Figure 2-2 in Chapter 2). 4. Grasp the toner sealing tape tab on the right side of the cartridge. Pull firmly to remove the strip of sealing tape. 5. Grasp the plastic cartridge body (not the metal shutter linkage), and slide the cartridge into the printer, pushing it firmly into place. Close the top door. — 3-3, Installation and Configuration Llnpacking and Installation

E. Load the paper cassette.

1. Pull out the paper cassette located at the lower front of printer and load approximately 100 sheets (4L/4ML) or 250 sheets (4P/4MP) of paper. The rear of the stack should fit loosely under the two backstops at the rear of the paper cassette. 2. Insert the front corner of the paper stack under the metal clip at the front of the cassette. Note Failure to insert the paper under the metal clip will cause skewing or paper jams. 3. Resting the paper cassette on a flat surface, slide it into the printer.

F. Attach the interface cable(s).

1. Open the 1/0 Door on the printer’s left rear side (LaserJet 4L/4ML only). Attach the 1/0 cable securely to the printer. Note Failure to attach the cable securely may result in an 1/0 error. 2. LaserJet 41J4ML: Align the cable with the cable hole and close the 1/0 Door. 3. Attach the I/O cable to the computer. 3-4, Installation and Configuration LJnpwking and hsbllattm

G. Attach the power cord.

1. LaserJet 4L/4ML: Open the Power Door at the right rear of the printer by pressing on the back end of the door and swinging it outward. 2. Connect the power cord. On the LaserJet 4P/4MP, turn on the power switch on the right side of the printer. All front panel lights briefly illuminate, then the green Ready light comes on. (LaserJet 4P/4MP: There is a brief self test period before the Ready and the On Line lights are illuminated and the display reads %3 FZIXW.) 3. LaserJet 4L/4ML: Align the power cord with the hole at the rear of the door and close the Power Door. 4. LaserJet 4L/4ML: Briefly press the front panel button to generate a self test and verify that the printer is working. LaserJet 4P/4MP: Press the - key, then Menu repeatedly until “%;;;T !%+:!..a!ppears. Then press _ once to display SZL.FT’zx-~. Press_ to print a self test. Id ~ J.~ Refer to the section “Printin~ a Self Test.” later U.JW L= in this chapter, for a detaile~ description’ of self test information. ~y~~ Power On/OfX The LaserJet 4P/4MP uses a conventional on/off power switch. The LaserJet 4L and 4ML printers do not have a power, switch, but use Intelligent On/Off sensing instead. (See “Intelligent On/Off in Chapter 5.) 3-5, Installation and Configuration Unpacking and installation

H. Attach the Help Labels (L-erJet 4~4ML onlY)

Packaged with the User’s Manual is a sheet of help labels. These labels explain the meanings of the front control panel lights. Attach the large help label to the inside of the printer’s top door, and the small label next to the front panel lights, as shown in Figure 3-1. Figure 3-1 Attaching the Help Labels (LaserJet 4L/LMUW 3-6,

I. Install Printer Drivers and Utilities (optional)

Printer drivers are specialized programs designed to allow specific software applications to function with the HP LaserJet printers. o Printer utilities include such things as the HP Explorer program modules, which enhance the usability of the printer and provide convenient access to printer features outside of specific software applications. ● How to Obtain Printer Drivers First, check the software’s printer selection feature to see if the printer is listed among the available printers. If it is not, run the software’s SETUP or INSTALL program to install a “ptinter driver” or “printer file” for the printer. Here are some ways to obtain printer drivers and Software Application Notes for HP LaserJet printers: ● Check the Printing Software package to see if it includes a driver ‘ for your software.Order an updated driver from the software vendor.Call Hewlett-Packard at 303-353-7650.Obtain a driver request form by fax through HP FIRST (call 1-800-333-1917).Download a driver through CompuServe’s HP Forum. To sign up for CompuServe, call 1-800-848-8199. ,,.,.., _ J’. , .-; While waiting for a specific HP LaserJet printer driver, you can substitute a similar printer driver (such as a driver for the HP LaserJet III, 111P, or 4 printer), These substitute drivers will allow you to use the printer, but they do not a support all of the printer’s features. 3-7, Installation and Configuration Unpacking and k“istallaiion Using the Printing Software Package The Printing Software package supplied with the printer provides many useful programs and utilities, including: Printer drivers for several popular software applications. Utilities for automatically copying printer drivers onto your hard disk. Software Application Notes for the above applications. The HP Explorer utilities, including . A setup program which installs other HP Explorer modules and automatically updates the computer’s AUTOEXEC.BAT and CONFIG. SYS files. Use the setup program to add or delete any of HP Explorer’s utilities at any time.The HP Explorer Remote Control Panel allows changes to printer settings from the computer’s screen. It supplements the software’s printer support to permit complete control over the printer’s features. ● The HP Explorer Status Monitor is a “Terminate-and-Stay- Resident” (TSR) program that automatically displays messages from the printer on the computer’s screen whenever the printer’s status changes.The HP Explorer Travel Guide is a guide to the printer’s features. It also serves as an on-line help utility when using other HP Explorer modules. 3-8, Installation and Configuration L/sing M Cbi’m91 FJWEd

Using the Control Panel

LaserJet 4L/4ML Control Panel Overview The HP LaserJet 4L/4ML printer’s front control panel consists of 4 status lights and a front panel button situated on top of the printer. w%-’ Fron.t .Panel A~ jwe 3-2 LaserJe4tL/4MLFront Ckmtrd Panel 3-9, Installation and Configuration The LaserJet 4L/4ML Lights The LED lights provide a quick way to check the printer’s status. Ready (Green) STEADY: The printer is ready to print a job from the paper cassette, BLINKING: If this light is blinking and the Data light is on steadily, the printer is receiving or processing data, Data (Green) STEADY: [f the Data light is on steadily and the Ready light is blinking, the printer is receiving or processing data. If the Data light and the Ready light are both on steadily, there is unprinted data still in the printer. Briefly press the front panel button to print the remaining data. BLINKING: The printer is in Manual Feed mode, Either insert a sheet of paper into the manual feed slot, or press the front panel button briefly to print from the paper cassette instead. Paper (Amber) STEADY: The paper cassette is empty or missing, Add more paper. BLINKING: There is a paper jam. Jam locations include the paper cassette, under the toner cartridge, or inside the printer’s rear access door. See Chapter 4 for clearing paper jams. Error (Amber) STEADY: The printer’s top door is open or the toner cartridge is either missing or not installed correctly. To correct the problem, make sure the toner cartridge is installed completely and close the top cover until it snaps shu~ BLINKING: The page is too complex. Press the front panel button to continue printing. There maybe some data loss on the page. Try setting Page Protect to On or Auto in the Printer Memory category of the HP Explorer Remote Control panel. If the page still doesn’t print correctly, you may need to install the optional printer memory. 3-1o, The LaserJet 4L/4ML Front Panel Button Depending on what state the printer is in, pressing the front panel button allows for control of printing tasks by either starting or resuming a printer function. Table 3-1 explains front panel button usage. FUNCTION I ACTION I Liahts I RESULT Self Test Press button for two READY light on Prints a Self Test page, seconds. briefly. Continuous Hold down button All lights cycle Prints continuous self tesi Self Test while powering on through. Release pages. Press the button printer (4L: about 5 button when DATA to stop printing. seconds, 4ML: about light only is on 15 seconds). (4ML: all lights on). Reset Press button for five Always available Clears all data from seconds or until lights except when all memory, including are flashing in lights are lit unprinted data, sequence. (Service Error). downloaded fonts and macros, Resets printer to factory default settings. FWake Up Press button for two All off. Takes the printer out ofseconds. Intelligent Off mode.Continue Press button for two Any recoverable Allows the printer toseconds, error code (see recover and continueChapter 7). printing the iob. Form Feed Press button for two DATA and READY Print remaining data in seconds, light on steady, printer memory. Manual Press button for two DATA light Override manual feed to Override seconds. blinking. print from paper cassette. Service Hold down button to All lights on steady. Press the button to Error display code. display service light Codes pattern. Use Chapter 7 to determine the problem and solution. 3-11, Installation and Configuration Using the Control F%nei

LaserJet 4P/4MP Control Panel Overview

The HP LaserJet 4P/4MP printer’s front control ~anel consists of a 16 character backlit LCD display, an 8 key contr;l panel, and 4 LED status lights situated on top of the printer. To access a primary key function (such as On Line, Form Feed, or Menu) just press the appropriate key. To access secondary key functions (Reset, EconoMode and -), use the_ key. For example, to access the “reset” function of the ~ key, press _ and ~ simultaneously. igure 3-3 LaserJet 41Y4MP Front Control Panel 3-12, Installation and Configuration using it%?Cmml Panel LaserJet 4P/4MP Control Panel Display and Lights The printer’s control panel has a 16 character backlit LCD message display area and four LED status indicator lights. A complete list of display panel messages is in Chapter 7. The following describes the functions of the four lights. Ready Light ON STEADY: There are no error conditions detected. The printer can only receive a print job when this light as well as the On Line light are on. BLINKING: The printer is receiving or processing data. Do not take off line or switch power off until the light stops blinking. OFF: The printer is not ready to print. Check the display panel for a message. On Line Light

EOnfine ON STEADY: The printer is ready to receive and process data,BLINKING: The printer is transitioning from the On Line to Off Linestatus.

OFF: The printer is off line (not ready to receive data). Other control panel keys can now be accessed. Form Feed Light l==+ ON STEADY: There is unprinted data still in the print buffer.w Press - to take the printer off line, then press~ to print the remaining data, BLINKING: Buffered data is being printed, OFF: No buffered data is in the printer. I I EconoMode Light itemnIIr ON STEADY: EconoMode is on. This reduces the amount of Ecw@70dc toner used on the page. NOTE: Software can override this selection, even while the EconoMode light is ON. OFF: EconoMode is off. To turn EconoMode on, press - to take the printer off line, then hold down_ while pressing the EconoMode key. 3-13, Installation and Configuration L!Sing the control Par%! %yMe 3=4 Lasel’w 4F/44JwMaw Map 3-14,

Service Mode (LaserJet 4ML/4P/4MP)

The Service Mode should be used only by authorized service personnel. While in Service Mode, you can: Print a Service Mode Self Test. Verify and set the Page Count (the page count also is displayed on the standard self test). Set the Cold Reset Default. (This sets the factory default paper size to either Letter or A4). Set the Demo Page=True/False. Used to remove the Demo Page option from the self test menu. Set the Diamostic Functions ON or OFF (for software developers &e only).

LaserJet 4ML

Since the HP LaserJet 4ML does not have a front control panel, Service Mode is accessible only through software (PJL commands). See “PJL Software Commands” later in this Chapter.

LaserJet 4P/4MP

The following procedure is used to initiate the Service Mode (refer to Figure 3-5). 1. Hold down the -, ~, and m keys while powering ON the printer, until all lights are illuminated and the Display Window is blank. (If the Display Window reads ,,....,”-..,..: :.:.:c...i,..,c ,, ,,,...:._.:,,.at this point, the keys were released too soon. Repeat this step until successful.) 2. Click the ~ key, then the - key. The message ,:...,...,@.,,,,..,.:...,,,.,,,,,..,,,,.,..,.-.~... .w..u?:is displayed briefly, then the printer automatically begins a ;j~ ~E!...F-:..W:.!.. After several seconds, both Control Panel Indicators turn OFF. (The printer may display ‘~? :R%w~i.![~:.;? if it has not warmed up completely.) After the printer has warmed up and passed the self test, .‘...-..”-L.-,.”..”...r..”:’“.”..’.”..””“i’,’!-.’.,K!,...Y.. i’sKdisplayed. 3-15 ‘, Installation and Configuration Service Mode (laserJet 41fiL/4P~4NP) To exit the Service Mode press them key.

SERVICEMODE SERVICEMENU PAGES

D\AGNOSTICS

J

.— Figure 3-5 Service Mode Menu Map (laserJet 4P14MP only) 3-16, Installation and Configuration swill% Mcwie &Sel’&?’i 4MLMFWMP)

Setting the Page Count (LaserJet 4P/4MP)

The page count is stored in the printer’s Non-Volatile Memory. If it is necessary to replace the Formatter PCA, the page count should be reset to the printer’s original page count to reflect the age of the print engine. Use the following procedure to set the page count: Before removing the old Formatter PCA, print a front panel self test to verify the current page count of the printer, if possible. Note If it is not possible to print a self test, try to verify the page count before replacing the Formatter PCA by following steps 3 through 5, below. After veriffing the page count from the old Formatter PCA, replace it with the new PCA as described in Chapter 6. 1. Enter the Service Mode as described in this section. 2. When fi~;~:.I..[$:E M[]CEis displayed, press the - key to access the Service Menu. 3. Press the m key to step through the menu. ~HfiiIS=J@LKYX is displayed.( ~ represents the page count currently stored in the printer’s Non-Volatile Memory. The underlined character denotes the cursor position. ) 4. Press the m key to scroll the cursor to underline the desired digit. 5. Press the m key to select the correct value. 6. Press - to store the new value in NVRAM. 7. Set each digit in the same manner. Press -to return the display to :%%~ICE WXE. 8. Press_asecond time to exit Service Mode. — Q 17, Installation and Configuration service Mode (Laserdet 4MLMPMMP)

Setting the Cold Reset Default (LaserJet 4P/4MP)

The default paper size for Formatter PCAS in Europe is A4. When replacing Formatters whose default is set for A4, set the Customization Variable to A4. When the Customization Variable is set to A4, the Cold Reset procedure will always reset the paper size to A4 (not to Letter). To set the Customization Variable: 1. Enter the Service Mode as described in this section. 2. Press the - key to access the Service Menu. 3. Press the ~ key to step through the menu until ,;-.,:;,7~.r~:,,r-,:,_-.m-.,.l-,Li.L.,:.-,,-,:..-.C...;,.C.,.,I>.S displayed. 4. Press the ~ key to toggle between Letter and A4 paper. 5. Press the ~ key to save your selection. 6. Press -to return the display to :=ti:..~t’ii tififii:. 7. Press - a second time to exit Service Mode.

Other Service Mode Items

The other Service Menu items, z::!” 2;?!H=: and ~:I:w%:3T I>;= are included for specialized purposes. If either item needs to be changed from the default setting (=%s..;.:: and :H%, respectively), the procedure is similar to that used for setting the page count or Cold Reset default, described above. 3-18,

Printing a Self Test

●

LaserJet 4L/4ML:

1, Make sure the Ready light is on, and all other lights are off. (If necessary, reset the printer. ) ● 2. Briefly press the front panel button (LaserJet 4ML, see Note below). 3. After about 6 seconds, the Data light blinks and the self test page starts to print (see Figure 3-6). Usually, only one page prints. If fonts or macros have been downloaded, a second page prints. .! ,,, .:, :*> LaserJet 4Mh The procedure above prints a “demo page” only on the LaserJet 4ML. To print PCL and PostScript configuration pages on the LaserJet 4ML, press and hold the front panel button down for at least 10 seconds, until the Data light is ON and the Ready light is blinking. Five pages will be printed (including font sample pages).

LaserJet 4P/4MP:

1. Press - to take the printer offline. The On Line light goes off and the display reads H’ CFT%...:i?i-. a 2. Press - repeatedly until “T:+T !+%:..:is displayed. 3. Press m to display :+KL..F‘[::~-~. ● 4. Press ~. The display panel reads {;:! ~;;i..~ ‘;>;;T’. After afew minutes a PCL Configuration self test page is printed (see Figure 3-7). a 3-19, installation and Configuration

Printing a %4$ Tesi Figure 3-6 shows a self test printout for the LaserJet 4L. It lists

al~factory default settings. “

J.

26 Scalable

Typefaces

Courier Univm’s Ed — Courier ad Un;vers Md It courier It Unfwers 8d M Courier Bd It Uuiws Md Cd Letter Gothic Umiwm Ed Cd Letter W.hi c Bd Umim MdCd,i Letter Goth]c !t Utivets M Wh CG Times Af)tlCme Ohre CG llmes Bd Aatiaue Olive Bd um CG ?hes it Antkwe Olive It****8**** CG ZWnesEd h Albems MdC’J.A Albertus XBd● EconoMode Univers tvld Wingdngrs3d%l%~%c—b******@**

HP Explorer LmR.4m W

L!3TBR OFF 3“ Mmmn.i

Ehhanced PCL 5 &

LTo

AUIO OFF OFF

12.0 10.0 EO!.(AN8

Bi-Tronics C.”rkr I-4 /RAMs;,. ,~~~ ~ytc, ~

POW,* P.9gCcmmk o * F)rmvm, Datcmdc : 15520927 ~Ii!!51 IWO Adapt Uti No CO”tml Errors None

Figure 3-6 LaserJet 4L Self Test Page (showing default settings)

3-20, Installation and Configuration Printing a SM Test

The LaserJet 4L Self Test Fields

1. Printer Features List. This area can be used to check for ● graphics print quality. 2. Scalable Typeface List. Samples of the printer’s internal scalable typefaces. ● hl’a’”a Removing ac power returns items 3 through 12 KVv,w to facto~-default settings (shown in Figure 3-6). 3. Paper Handling. Shows the current paper settings. 4. Print Quality Adjustment. Current settings for print density and Resolution Enhancement (REt). 5. Memory Configuration. Settings for Image Adapt, Page Protection, and Auto Continue. 6. EconoMode. Setting of this toner-saving feature. 7. Font Selection. Current default printer font settings. 8. RAM size. Shows the total amount of installed printer memory, including added optional memory. Use to verify proper memory installation. 9. Page Count. Shows approximately how many pages have been printed since the last power on. This value is returned to zero whenever the printer is powered off. 10.Firmware Datecode. Shows the datecode of installed firmware in YYYYMMDD format. ● 11. Image Adapt Status. Displays YES if the Image Adapt datacompression feature has been invoked since the last power on. 12. Control Errors. Shows the number of 1/0 or misprint errors since the last power on. ● 3-21,

Installation and Configuration Pining a sell Test

~ ●Pm ,.”fig m.,, .—...—— .—-m-...——..=—— ~20 PRINTING MENU PCL MEMU$ERVICE MENU ~ COPIES = 3 can mm : : <1..-.1)PAGES FWT WBER CR PAPER = lF1lER PAPER - LETTER SKIP DEMO = FALSE ::;:NTAT IO!. : :ol POrr$it 1 PITCH = 10.00 SW SE7 = RCMAM8 !31AGNOSTICS = OFF ~ FEm . OFF = ,fDlw WNFIG MEMU Ps E vu JOB MENU m WARN ~ : m, P* ,,,s = m ,MEDROT ECT : yJo RESWJTIDM AUID cCW ● PERSONALV : $~:0 ,,, s,,, = 3 T ,“SOUT PMALIE L MENU SERIAL WI!.U TE$T MEW HI,” S.EED = “ES SFXIAC . R.-232 ,,,, ,,,, P,C 1NC = El RIO* Law SELF TEST#lW FI:TNS = ON mm RAW = 96C+ PC1 lVPE 11ST m POLARITY - nr ,,, mm PA m,.. .—W, .!,..m...f,.., ,$ TWf FACE L 1S1 ,S DEMO PAGE r 3-22, Installation and Configuration Printing a Self Test

The LaserJet 4MIJ4P/4MP Self Test Fields

The numbered items below refer to the Service Mode PCL Configuration Self Test Page shown in Figure 3-7. o 1. Menu Selections: Shows the current selections for all Service menu and user menus in the order that they appear in the control panel display (refer to the Menu Maps, Figures 3-4 and ● 3-5). Use this information to verify the various menu selections. 2. PS Menu: Appears on the LaserJet 4P only if the Adobe PostScript SIMM is installed. 3. LocalTalk Information: LaserJet 4MP only. Lists the cotilgured network name and node identification number. 4. EconoMode Status: Shows current status, ON or OFF. 5. Formatter Numbefi Shows the Formatter PCA’S serial number. 6. RAM Size: Shows how much memory is installed in the printer. 2048 Kbytes is standard. If optional memory has been added, a self test can be used to verify installation. ‘7. Page Count: Shows how many pages have been printed over the life of the printer. 8. Firmware Datecode: Shows the datecode of the installed firmware (in YYYYMMDD format). 9. Installed Options/Personalities: Lists recognized cartridges a and personalities. Use to verify installation. 10.REt Status: Shows the current Resolution Enhancement setting, LIGHT, MEDIUM, DARK or OFF. (Default is m MEDIUM.) 11. Sample Printi Shows ripple print pattern (always in Courier). This area is useful for checking print density and quality. ● 3-23, Installation and Configuration Printing a Self Test

Continuous Self Test

A continuous self test can be useful for troubleshooting paper path and other problems. To print a continuous self test: LaserJet 41J41VIIA 1. Disconnect the printer from the power source. 2. Press and hold down the front panel button while connecting power. 3. Continue holding the button for: 4L - about five seconds; 4ML - about 15 seconds. All lights will illuminate at once, then: 4L - each will light in sequence; 4ML - all lights stay lit. 4. Release the button. The printer conducts its internal diagnostics routine, then prints the self test page continuously until stopped. 5. To stop the continuous self test (and reset the printer), press and hold the front panel button for a few seconds until all lights begin lighting in sequence once again. (4ML - the printer can take up to 2 minutes to clear the buffer and stop the self test.) LaserJet 4P/4MP 1. Press - to take the printer offline. The On Line light goes off and the display reads W3 IHFFL1 NE. 2. Press - repeatedly until T!Z5T PEW-l is displayed. 3. Press ~ until EUHT SELF TE:ST is displayed. 4. Press ~. The display panel reads W SELF TEST. After a few minutes a PGL Confirmation self test ~a~e is minted (see Figure 3-7). The self test-page will print m~l~ple ~opies, continuing until the - or ~ key is pressed. 3-24, Installation and Configuration Engine Test

Engine Test

The engine test print can be used to verify that the print engine is functioning correctly. The Formatter PCA is completely bypassed during an engine test. This testis therefore useful for isolating printer problems. The engine test prints a fhll page of vertical lines down the entire printable area, and is thus also useful for checking and adjusting re&istration. Note An Engine Test can be performed on the LaserJet 4L and 4ML with the printer covers in place, as shown in Figure 3-8. The LaserJet 4P and 4MP require removal of the covers and the Formatter PCA. Refer to “Engine Test” in Chapter 7 for the engine test procedure. — Figure 3-8 Engine Test EWcm and Printout (LaserJet 4L shown] 3-25, Installation and Configuration Resetting the Printer

Resetting the Printer

Resetting the printer clears the printer’s memory, including unprinted data, downloaded fonts, and macros. It also removes some error conditions, and resets to factory default settings. The printer can be reset at any time, except when there is a service error condition.

LaserJet 4L/4ML:

1. Hold the front panel button down for at least five seconds. Release when all lights illuminate in succession from bottom to top. 2. After the printer has finished the reset, the Ready light comes on (if there are no printer errors).

LaserJet 4P/4MP:

The LaserJet 4P/4MP has several kinds of resets, as explained below. Simple Reset A simple reset does the following: Clears the printer’s page buffer. Removes all temporary typefaces and macros. Makes the current user-selected defaults “active” (making them the default values until you change them again). Purges the input buffer of the active 1/0 (the other I/O buffer is not affected). To perform a simple reset: 1. Press_ to take the printer offline. The On Line light goes off and 2S ]H%i-Ii!~ appears on the display. 2. While holding down the ~ key, press - briefly. 3. S7 ~~s~~ appears on the display. Then the printer returns to the on-line, 5E Z=W+ state. 3-26, Installation and Configuration Resetting the Printer The Menu of Resets Additional reset options are available through the Menu of Resets. Use the Menu of Resets option with caution. It can result in loss of buffered page data or printer configuration data. You should only use it when: You wish to restore the default printer settings. Communication between the printer and computer is interrupted. You are using both the serial and the ~arallel I/O ~. orts. and one of the ports ii having problems. ‘ To access the Menu of Resets: 1. Press - to take the printer offline. 2. Hold down both the ~ and ~ keys for at least 10 . seconds until ==:;:=-~=mw!appears on the display. 3. Use ❑ or H to cycle through the items. 4. Press ~ to select your choice of resets. An asterisk * appears by the reset option. 5. Press - to execute the reset. The foIlowing table shows the three reset options. Table 3-2 Menu of Resets (LaserJet 4P/4MP) Menu Selection Printer Response Explanation RESET.MENU 09 MENU RESET RESET=MENU restores most of the printer’s factory default settings. It also performs a simple reset. Items in the Config, Parallel, and Serial Menus are not reset, RESET=MENU clears only the active input buffer. RESET.ACTIVE 1/0 09 RESET ACTIVE 1/0 RESET= ACTIVE 1/0 clears the input and output buffers for the active //0 dy, and performs a simple reset. RESET ALL l/O 09 RESET ALL 1/0 RESET=ALL l/O clears the input and output buffers for both 1/0s, and performs a simple reset. 3-27, Installation and Configuration Resetting the Printer

The Cold Reset (LaserJet 4ML/4P/4MP)

Cold reset clears all data from the printer’s memory and sets all the defaults back to the factory settings. (NOTE: The LaserJet 4L a is effectively “cold reset” whenever power is removed.) To perform a cold reset: LaserJet 4ML: Cold Reset can be performed on the LaserJet 4ML through the HP Explorer Utility (refer to the Software/Solutions package for instructions). LaserJet 4P/4MP: 1. Turn off the printer. 2. While holding the _ key down, turn the printer on. m !CDLER,ESET appears briefly on the display, then 13z !PJL Software Commands Many of the control panel functions explained in this chapter can also be accessed through PJL software commands sent from the host computer. For the LaserJet 4ML printer, functions such as entering Service Mode, are accessible only through PJL commands. (Note that Service Mode is available only on the LaserJet 4ML, 4P and 4MP, and not on the LaserJet 4L.) The following example shows how to use PJL commands to enter Service Mode and perform various Service Mode configuration tasks. Note Text is CASE-sensitive in PJL; enter exactly as shown. The Ec symbol stands for the ASCII escape character (ESC or /027). When the PJL code is entered, print the data file (or use the DOS COPY command to copy it to the printer). Table 3-3 Example: PJL Service Mode Commands PJL Command Explanation ‘cYo-l 2345X@PJL Start PJL job. @PJL SET SERVICEMODE=HPBOISEIE Enter Service Mode @PJL SET PAGES=O Set page count [= XXXXX] @PJL SET CRPAPER=LETTER Sets cold reset page size [= Letter/A4] @PJL SET SKIPDEMO=FALSE Skips demo/PCL type page [= true/false] @PJL SET DIAGNOSTICS=OFF Sets diagnostics [= OFF/ON] (for ISV use) @PJL SET SERVICEMODE=EXIT Exits Service Mode @PJL DEFAULT PAPER. LETTER Selects user paper size default @PJL RESET Performs PJL reset ‘cYo-l 2345X Exits PJL mode Ecz Prints Self-Test page ECE Resets the printer. 3-29, Installation and Configuration PJL Software Commands 3-30, b’ ● Maintenance, Maintenance Service Checkpoints

Service Checkpoints

Figure 4-1 Service Checkpoints 1. Upper Fusing Assembly, 6. Front Oblique Roller. 2. Beam-to-Drum Mirror. 7. Pickup Feed D-Roller. 3. Transfer Roller Assembly. 8, Photosensitive Drum. 4. Toner Cartridge. 9. Fusing Pressure Roller. 5, Registration Roller. 10. Face-Up/Face-Down Deflector. 4-2, Maintenance Life Expectancy of Consumables

Life Expectancy of Consumables

Always inspect the components listed in Table 4-1 for wear when servicing the printer. Replace these components as needed, based on printer failures or wear, not strictly on usage. Table 4-1 l-ik l%pectamy cdConsumables

EST

DESCRIPTION PART NO. LIFE REMARKS (P9S) Toner Cartridge 92274A 3000’ When print becomes faint, (user replaceable) shake cartridge to distribute remaining toner. Transfer Roller RF5-0596-OOOCN 100,000 May affect print quality and /or ~a~er movement, Pickup Feed D-Roller RBI-3368-OOCN 100,000 Look for glazing andlor cracks. Pickup Assembly RG5-0796-OOOCN 100,000 Look for glazing andlor cracks, gear wear, sticky solenoids, etc. Front Oblique Roller RG5-0669-OOOCN 100,000 Look for glazing andior Assembly cracks, Fusing Assembly 100,0M0a0y affect print quality and 100-120 V, 50/60 Hz RG5-0676-OOOCN /or paper movement, Look (exchange part no.) C2003-69001 for marks on lower pressure roller or upper Teflon sleeve. 220-240 V, 50 Hz RG5-0677-OOOCN (exchange parl no.) C2003-69002 1 * The estimated toner cartridge life is based on Letter or A4 size paper with an average of 5% toner coverage and a medium density setting. Toner cartridge life can be extended further by conserving toner using the printer’s EconoMode feature. 4-3, Maintenance Life Expectancy of Consumables

Toner Cartridge Life

The toner cartridge has been designed to simplify the replacement of the printer’s major “consumable” parts. The toner cartridge contains the printing mechanism and a supply of toner. A toner cartridge will print approximately 3000 pages when using a typical word processing application, in which text covers about 5% of the page (see Figure 4-2). Figure 4..2 Sample 5% Rage Coverage 4-4, Maintenance Life Expectancy of Consumables When regularly printing pages with less coverage, such as short memos, a toner cartridge should print over 3000 pages. However, if routinely printing very dense print, the cartridge will not printaafull 3000 pages. Note For best results, always use a toner cartridge before the expiration date stamped on the toner ● cartridge box.

Saving Toner with EconoMode

Toner cartridge life can be extended dramatically by using the EconoMode printing feature of the printer. EconoMode can be turned on or off via the printer’s front panel (LaserJet 4P/4MP only), through HP Explorer’s Remote Control Panel or through a software application with the appropriate printer driver. See Chapter 3 for information on the HP Explorer Remote Control Panel. Notes EconoMode functions in portrait orientation only. Some software applications may refer to this as “draft mode.” Software settings always override front control panel selections (LaserJet 4P/4MP). o ● ● 4-5, Maintenance Cleaning Printer (hnponents

Cleaning Printer Components

CAUTION Do not use ammonia-based cleaners in or around the printer. They will cause damage to the toner — cartridge’s photosensitive drum. Table4-2 Cleaning Printer Components COMPONENT I CLEANING METHOD/NOTES I Outside Covers Use a water-dampened cloth. Do not use solvents or ammonia-based cleaners. Inside General Use a dry, lint free cloth. Remove all dust, spilled toner, and paper particles. Front Oblique Roller Use a cloth or swab dampened with ethyl or isopropyl alcohol. Pickup Feed D-Roller Use a water-dampened lint-free cloth. Registration Roller Use a dry lint-free cloth, Transfer Roller Use a dry, lint-free cloth. DO NOT TOUCH with your fingers. Beam-to-Drum Mirror Use filtered, compressed air first. If not effective, use a lint- free cloth or swab dampened with lens cleaner. Fusing Pressure Roller Use a cloth or swab dampened with water. Face-up Deflector Use a cloth or swab dampened with water. 4nti-Static Teeth Use compressed air. Refer to Chapter 6 for removal procedure. WARNING!:The Anti-Static Teeth are extremely sharp. Be careful! 4-6, Maintenance Cleaning Printer Components a

Cleaning Spilled Toner

Defective toner cartridges can develop leaks. In addition, after a ● paper jam has occurred, there may be some toner remaining on therollers and guides inside the printer. The pages that print immediately after the jam may pick up this toner. Clean spilled toner with a cloth dampened in cold water. Do not ● touch the Transfer Roller with the damp cloth or your fingers. Do not use a vacuum cleaner unless it is equipped with a micro-fine particle filter. Note If toner gets on your clothing, use cold water to remove it. Hot water sets toner stains into fabric. 4-7, Maintenance Clearing Paper Jams

Clearing Paper Jams

— ● Note Paper jam messages (or status lights) will not clear until the printer’s Top Door is opened, then closed, or the front panel button (4 L/4ML) or ~ key (4P/4MP) is pressed. @ Paper jams can be caused by a variety of factors: ● Leaving the rear door open. ● Filling the paper cassette too full. ● Using paper that does not meet specifications (see “Media Specifications” in Chapter 2). ● Removing a paper cassette while a job is printing. e Failing to place the corners of the paper stock under the front and rear retainer clips in the paper cassette. ● Printing a letter size job on legal paper. Note Remember to check for loose paper particles and clean any spilled toner after a paper jam has _ been cleared. There are three areas of the printer where paper jams can occur: ● The Paper Feed Area @ s Inside the printer ● Paper Output Area ● 4-8, Maintenance Clearing Paper Jams

Paper Jams in the Paper Feed Area

1. Open the top door by pressing the door release button on the upper right side of the printer. 2. Take out the toner cartridge. (Do not expose the toner cartridge to light for more than a few minutes. Cover it while working on the printer.) 3. Pull out the paper cassette. 4. If paper is in the paper feed area, pull the paper to the right to relea”se it from the o-blique feed rorler. Then pull the paper straight out. CAUTION Be careful not to get paper particles caught in the front oblique roller. This can cause repeated jams. Figure 4-3 Paper Feed Area Jam 5. If Step 4 clears the jam, replace the paper cassette and the toner cartridge, then close the top and rear doors. The printer should return to the Ready state. If it does not, there may still be jammed paper in the printer. Check the top and rear areas of the printer (see the next page). 4-9, Maintenance Clearing Paper Jams

Paper Jams Inside The Printer

1. Remove the toner cartmidge and paper cassette. While holding the printer steady, carefully pull the jammed paper straight out the front to remove it. CAUTION - Do not pull the paper straight up when removing it. The toner on the paper may contaminate the printer and beam-to-drum _ mirror. l-+! \m\Y I Figure 4-4 Clearing Jams from the Toner Cartridge Area 2. If the trailing edge of the paper is under the transparent .t cover, pull the paper out and around to remove it. /’

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Figure 4-5 Clearing Jams from the Paper Guide 4-1o, Maintenance Clearing Paper Jams 3. If the paper is difficult to remove, you need to relieve some of the pressure in the Fusing Assembly. Open the printer’s rear access door. While holding the green paper release lever up, e pull the paper out. Figure 4-6 Releasing Paper from the Fusing Assembly 4. Replace the paper cassette and the toner cartridge, then close the top and rear doors. The printer should return to the Ready state. If it does not, try one of the following remedies: . Ensure the rear access door is fully closed and latched.Check to see if there is more jammed paper in the printer (see the next page).Open and close the printer’s top door or press the front panel button briefly. ● 4-11, Maintenance Clearing Paper Jams

Paper Jams in the Paper Output Area

1. Open the printer’s Top Door and remove the toner cartridge, 2. Open the rear access door. CAUTION - Do not touch the fusing assembly. It maybe hot. 3. Wile pushing the green paper release lever up, pull the paper out. (This lever releases pressure on the fuser roller.) Figure 4-7 Clearing Jams from the Fuser Area 4. Be sure to close the rear access door again. Leaving the rear access door open will cause a paper jam. — Note If there is still a paper jam error condition, check the paper feed and top door areas for paper or particles. If the error persists, refer to — Chapter 7, “Troubleshooting.” 4-12, ...— - r Ill w

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Basic Printer Functions

● This section of the manual presents a generalized functional overview of the printer. It is designed ;O provide an understanding of the processes that occur during printing. The following basic printer functions are discussed: — DC Controller System Formatter System Image Formation System Paper Feed System Power System Basic Sequence of Operation Fig-are 5-1 is a generalized block diagram of the printer: - - - ., T..“.4 ~- ..-,“ UA,v)!!w -.!.-+1 I (w. husi campUer) 1 -J Facadown delivery hay , ma the bkdirectl onal 1/0 1 [ I I - J: t : LASERISCANNERSYSTEM ~ ;_ Mimi, I1t1Formaner PCA 1 , , , 4 :Ez+ 1 - - -1 , I Scanner1I, lm-oltort , 1 - I-r- -,- 1 - , I ‘- %ii6E-~O%ilii16iiIo‘ , , , t , , , +Fuser:11,,t,,,I ,1 ,-..- - T t J- , , I C2ssene t P-I-C-K-.-U-P-/FEED SYST , ~- -1-3-1- Figure 5-1 Printer Functional Block Diagram 5-2, Functional Overview DC Controller/Power System DC Controller/Power System ● The DC Controller PCA is responsible for coordinating all print engine activities. The DC Controller drives the laser, coordinating print data from the Formatter PCA with the image formation process. The DC Controller shares machine status information a with the Formatter PCA so that proper diagnostic messages are displayed. The DC Controller also provides both ac and dc power supply and distribution circuitry. Figure 5-2 shows the various DC Controller loads.

EFolntCartridge DC Controller PCA Laser/Scanner(4P Only) Assemb

— Laser

L CPU bDiode

Fogn#er dSensors uFanand I MotorSolenoidsI1Main Motor

F PDC Power Supply i

+lTransfer Rollerl Ir—————l

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17gwe 5-2 IX CofitrollerLoads 5-3, Functional Overview DC Controller/Power System In summary, the following systems and functions are controlled by the DC Controller: ● . Print Engine Control ● Laser and Scanner Drive ● ● Paper Motion . Microswitches (Top Door and Engine Test) . Motors (Main Drive, Scanner, Fan) @ Power System . AC Power Distribution ● DC Power Distribution ‘ . High Voltage Power Distribution . Overcurrent/Overvoltage Protection ● ~nte]iigeonn/Otff (LaserJet 4L/4ML only) 5-4, Functional Overview DC Controller/Power System

Print Engine Control

● Laser and Scanner Drive Based on information received from the Formatter. the DC Controller sends a signal to the Laser/Scanner PCA to modulate the laser diode ON and OFF. The modulated laser beam strikes the surface of a rotating scarming mirror, is directed through a ● focusing lens onto the Beam-to-Drum Mirror, and is then reflected onto the photosensitive drum. Synchronization of the process is achieved by continuous monitoring of the beam detect signal, which is fed back to the system from one end of the focusing lens. Refer to “Image Formation System,” later in this chapter for more information. Paper Motion Monitoring and Control The DC Controller PCA controls paper motion by continuously monitoring the various paper sensors, and coordinating the timing with the other print processes. For a detailed explanation of paper movement, and the interaction of photosensors and solenoids with the paper movement process, refer to the section “Paper Feed System,” later in this chapter. 5-5, Functional Overview DC Controller/Power System Top Door/Toner Cartridge Microswitch (SW201) Microswitch SW201, located on the DC Controller, is activated by both the top door and the toner cartridge. If either the top door is open or the toner cartridge is not installed, the switch opens and an error is issued by the Formatter. On the LaserJet 4L/4ML, the front panel’s Error (topmost) LED turns on steady. On the LaserJet 4P/4MP, the display panel message I;: :x+;: D’ i+~ EPis displayed. A toner cartridge must be present and the top door must be closed before the printer can resume printing. Top Door Plunger ~) Printer Chassis Top Rail L J\ *A k-t-PlungerAssembly Body - Transfer Roller A DC Controller PCA \! R-,rac.c-.4 Plate I \ \ / / \ ‘switchActuator’ Top Door Microswitch (SW201 ) Metal Switch Arm Figure 5-3 Top Cover/Toner Cartridge Plunger & Microswitch (cutaway view) 5-6, Functional Overview DC Controller/Power System Engine Test Microswitch (SW301) Microswitch SW301, also located on the DC Controller, is activated manually through an access hole in the Drive Train Assembly on a the left side of the printer. This switch causes the print engine to perform a self test diagnostic, bypassing the Formatter PCA. This test is useful for troubleshooting printer problems because it isolates the print engine from the Formatter. The engine test ● prints a single page of vertical black lines, which can also be usedfor adjusting print registration. See “Engine Test’ in Chapter 7 for more information. Note The Engine Test print button can be accessed on the LaserJet 4L/4ML by opening the 1/0 Door. On the LaserJet 4P/4MP, the printer covers and Formatter PCA must be removed first. Motors The Main Motor (Ml) is controlled by the DC Controller PCA. The Main Motor rotates during the Initial Rotation period (following initial power-ON), the Print period, or the Last Rotation Period, or whenever the printer’s top door is opened and closed. The Scanner Motor (M2) is controlled and monitored by the DC Controller and Laser/Scanner PCAS. The Scanner Motor operates during the Initial Rotation period and the Print period. The Exhaust Fan Motor (M3) is controlled and monitored by the DC Controller PCA. The Exhaust Fan Motor operates for approximately 35 seconds during power-ON and Standby. It remains on during Initial Rotation, Print, and Last Rotation a Periods. 5-7, Functional Overview DC Controller/Power System

Power System (on DC Controller PCA)

The ac, dc and high voltage power supply circuits are all contained within the DC Controller PCA. ● AC Power Distribution The ac power circuitry, located on the DC Controller PCA, supplies ac voltage to the DC Power Supply whenever the printer’s power cord is connected to the ac power source. (The power switch must o be turned ON in the LaserJet 4P/4MP.) A toner cartridge must be installed and the top door closed before voltage is supplied to the High Voltage Power Supply or Main Motor drive circuitry. DC Power Distribution The DC Power Supply circuitry, located on the DC Controller PCA, generates +5 V dc, and +12 V dc, which is used as follows: +5 V dc: Formatter PCA Photosensors DC Controller Circuitry Laser/Scanner Assembly +12a V dc: High Voltage Power Supply (a=after switch) Main Motor +12b V dc: Solenoids (b=before switch) Laser/Scanner Assembly (to Fan) The Power System Block Diagram is illustrated in Figure 5-4., Functional Overview DC Controller/Power System Power supply Main switch r -, SW201 I [4P/4MPOnly) I-I-*-1-

DFusingHeeter

~ Fuse Mm, (FU201) of+12bV Door switch ... Y SW201 : H]gh- :+12V 2NoW T, +12av 1 uOlta9e\ 12b V=Voltage power ; power ; before switch filter supply -k” : “ circuil 12a V=Voltage: k+ 1 .‘.circutl ‘u. .p.’”.:., cafter swit1ch,

I

a !-...~ MainRegula!or nMainmotor : momr Mainsub supply -.-i dflve Motoroower circuii ; drcuit o+12a VOvervoltage/ d Solanoid IIovercurrentdetection Kcircuit 1 +5V -I -wm‘VHElFan motor301

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e EFormetterPCA mmorvionmg input ~-SW Figure 5.4 Power Supply Block Diagram 5-9, Functional Overview DC Controller/Power System Overcurrent/Overvoltage Protection The +12V dc and +5V dc power circuits each contain an overcurrent/overvoltage protection circuit which automatically shuts off the output voltage when an overcurrent condition occurs due to a short or abnormal voltage on the load side. The protection circuit automatically resets after the input power is cycled OFF then ON. Fuse FU101 provides overcurrent protection for the Fusing System circuitry. Fuse FU201 (not present on 220-240 V units) provides protection in case of a catastrophic overcurrent condition in the DC Controller power supply regulation circuitry. Intelligent ON/OFF (LaserJet 4L/4ML only) This printer feature conserves power by shutting down all the printer’s front panel LED status lights after a 15 minute period of inactivity. The printer retains all printer settings and downloaded fonts and macros while in Intelligent Off mode. The lights power ON instantly when any of the following occur: e A file is printed. @ The front panel button is pressed.The printer’s top door is opened.Paper is inserted into the manual feed slot. ● A paper cassette is removed or installed. Note – The printer will not enter Intelligent Off mode if there is a printer error. 5-1o,

Functional Overview DC Controller/Power System High Voltage Power Distribution The High Voltage Power Supply circuitry, located on the DC Controller PCA, applies an overlap of dc and ac voltage to the

a primary charging roller and the developing cylinder. This circuit also applies a positive or negative dc voltage to the transfer charging roller according to the instructions from the CPU on the

DC Controller PCA.

a This circuit also controls the image density by changing the primary ac voltage and the developing ac bias according to the image density signal from the Formatter.

Figure 5-5 shows the timing of the high voltage power supply.

Power ON (U.,? second) WAIT ISBY! lNTR J PRINT LSTR ST8Y PRINT s,gnal (/PRNT) \ — VERTICAL SYNC 7 signal (f70P) I, i , n Matn rmbr ~1.7t021 I — Scanner motor I 042 Im PnrnarY voltage (AC) I P,imar~ voltage (DC) I IllItDevelwing bias (AC) I 1 ~ Developing bias (DC) I I%H + I@%l I ,-071 Transfer voltage ~ Laser diode I , lll[lllllll!~llllilll ● Note: The transfer vcdtage changes according !0 the print sequence as follows: -: Bek3en-fxigebL9s (Iowerpositw voltagethan the pr,nt bias isap,pleototfw Wa”s[ercharging roller to prevent the damage of the photosensmve drum) -: Negative bias (negative voltage is appli~d to the transfer charging roller for cleaning) a m: Print bms (POSMW vokage is app,edtofhetrans ferchargi”g mlerto tm”sterttw toner on thephotosensitive dmm sudsce to the paper)

Figure 5-5 High Voltage Power Timing

o 5-11, Functional Overview Formatter System

Formatter System

The Formatter PCA is responsible for the following: . Receiving and processing ASCII data from the various printer interfaces. s Monitoring front panel input and relaying printer status information (through the front panel and the hi-directional 1/0).Developing and coordinating data placement and timing with the print engine. ● Storing font information. ● Communicating with the host computer.... ~ DC Controller ! ~Host Computeri.- - -... ‘“-”$-”-” t..-._.-.4L-L - -.-,7- ...- .17+ Formatter PCA Video Ttming 1/0 Controller ROM Interface Controller

I J I

d CPU On Control PanelBoard RAM Interface ? _,~I .-..-...-...-... Figure 5-6 Formatter Block Diagram 5-12, Functional Overview Formatter System The Formatter PCA receives ASCII data from the Bi-Tronics Interface and converts it into a dot image. The image orientation (portrait or landscape) and the font type are both selected. When the scan buffer is full, or when a Form Feed command is received, the Formatter sends a PRINT signal to the DC Controller. The DC Controller synchronizes the Image Formation System with the Paper Feed System, and signals the Formatter to send the print image data. The Formatter sends the print image data (dots) in the form of a VIDEO signal and the printing process begins.

CPU

The Formatter PCA incorporates the following microprocessors: ● LaserJet 4L - Motorola 68000, 16 MHz. ● LaserJet 4ML - Intel 80960KA, 18.5 MHz.LaserJet 4P - Intel 80960SA, 16 MHz.LaserJet 4MP - Intel 80960KA, 18.5 MHz, 32K instruction cache.

Read Only Memory (ROM)

Besides storing microprocessor control programs, the ROM stores the dot patterns of internal character sets (fonts).

Random Access Memory (RAM)

The RAM stores printing and font information received from the host system, and can also serve to temporarily store a full page of print image data before the data is sent to the print engine (see “Page Protect”). RAM memory capacities for each printer are shown under “Printer Features” in Chapter 1. Note that adding memory will not increase 1/0 buffer space or print speed. Note The LaserJet 4P/4MP printers support 32-bit SIMMS (C303XA series) as well as the 36-bit SIMMS (C206XA series) used in earlier LaserJet family printers. 5-13, Functional Overview Formatter System

Non-Volatile Memory (~)

LaserJet 4L: The HP LaserJet 4L printer does not use NVRAM. As long as the printer is connected to an ac power source, configuration and page count information (as well as any downloaded fonts and macros) is retained in conventional RAM. When power is disconnected, RAM contents are lost, page count returns to zero, and the printer returns to factory default settings. LaserJet 4ML/4P/4MP: 256 bytes of NVRAM is used on these printers to store 1/0 and print environment configuration information. The contents of NVRAM are retained when the printer’s power is turned off or disconnected. (As in other HP LaserJet printers, downloaded fonts and macros are saved in conventional RAM, and are lost when power is turned off.)

Parallel Interface

The Formatter PCA receives incoming ASCII data through its Bi-Tronics interface connector. The Bi-Tronics 1/0 provides high speed two-way communication between the printer and the host, allowing the user to change printer settings and monitor printer status from the host computer. The Bi-Tronics I/O is compatible with the Centronics parallel interface standard. Note — Refer to “Parallel Cable Pin Configuration” in Appendix B for parallel pin assignments. High Speed (Yes/No) The “High Speed (Yes/No)” configuration item is user-selectable. The default setting, “Yes” allows the I/O to run at the higher speeds supported by most newer PCs. If the mode is set to “No,” the parallel interface runs at the slower, but compatible mode for older PCs. Advanced Functions (On/Off) The “Advanced Functions (On/OffY configuration item is also user-selectable. The default setting, “On” allows for “Bi-tronics” two-way parallel communications. The “Ofi” mode disables the Bi-tronics advanced functionality. 5-14, Functional Overview Formatter System

Serial I/O (LaserJet 4P/4MP)

The LaserJet 4P/4MP printer supports RS-232 compatible serial ● communications. The printer uses a 9-pin D-subminiature connector. (See Appendix B for pin-out information.) Pacing (Serial Modes of Operation) The “Pacing” configuration item is user-selectable. Available choices under Pacing are: @ * DTIUDSR (default) - This mode, primarily implemented for PCs, has hi-directional data flow which is paced using hardware pacing. No XON or XOFF signals are sent. e XON/XOFF - This mode is primarily intended for UNIX machines which cannot perform hardware pacing yet want hi-directional data flow. Data flow is paced using XON and XOFF signals to indicate when the printer is ready to accept new data from the host.

LocalTalk I/O (LaserJet 4ML/4MP)

The LaserJet 4ML/4MP printers implement the AppleTalk networking protocol through the LocalTalk hardware. The LocalTalk network cable (HP P/N 92215N) is connected through an 8-pin DIN connector on the printer’s I/O panel. (See Appendix B for more cabling information.) 5-15, Functional Overview Formatter System

Control Panel

LaserJet 4L/4ML Status LED Lights: The Formatter uses four lights to communicate printer status to the user. Light from the LEDs is transmitted through a single piece Light Pipe Assembly, mounted on the inside of the printer cover. Refer to “Using the Control Panel,” in Chapter 3, and to “Printer Error Troubleshooting” in Chapter 7, for more information on the lights. Front Panel Button: The Formatter PCA includes a microswitch which is activated by the front panel button through a switch actuator which mounts on the surface of the PCA. The single button is used for such functions as self test, reset and displaying error codes. Refer to “Using the Control Panel,” in Chapter 3 for more information on the front panel button. LaserJet 4P/4MP The Formatter PCA on the LaserJet 4P/4MP sends and receives printer status and command data via a Control Panel PCA, which consists of an LCD display window and an 8-key keypad. LCD Display Window: The Formatter uses a backlit 16-character LCD display window in conjunction with three lights to communicate printer status to the user. Display window messages can be configured in any of several languages. 8-Key Keypad: The eight keys on the keypad are used for a variety of functions, such as switching online/offline, configuring the printer, initiating self tests, form feeds, or resets, and turning EconoMode on and off. A keyboard overlay is available in any of several different languages (see Chapter 8 for part numbers). 5-16, Functional Overview Formatter System

Resolution Enhancement (REt)

The printer’s Formatter PCA contains circuitry for Resolution o Enhancement technology (REt), which modifies the standard video dot data on its way to the DC Controller to produce “smoothed” black-to-white boundaries. REt is user-adjustable from the front control panel (LaserJet 4P/4MP only), from HP Explorer’s Remote Control Panel (Print Quality Category), or from some software ● applications. Available settings are Light, Medium, Dark, or Off. The default setting is Medium. Note REt settings sent from software or printer drivers override any control panel settings.

Print Density Adjustment

Adjusting print density affects the line width (boldness) of the print image. This is accomplished by varying the developer dc bias, which controls the amount of toner applied to the photosensitive drum. Print Density is adjustable through HP Explorer’s Remote Control Panel (Print Quality Category). The range of settings is from 1 (lightest) to 5 (darkest). The default setting is 3. 5-17, Functional Overview Formatter System

EconoMode

The EconoMode setting uses approximately 50% less toner than standard mode printing by reducing the dot density. EconoMode, which can also be thought of as “draft mode,” is user selectable via a front panel key (LaserJet 4P/4MP only), or via a PJL sequence using HP Explorer’s Remote Control Panel, or through application software. The default setting is Off. Normal Mode, Medium Density _*- _*.-*-@*g* EconoMode, Medium Density ● O...*-*-’” ● -m-e Figure 5-7 EconoMode vs. Regular Print — Note EconoMode does not affect print speed or — memory usage. 5-18, Functional Overview Formatter System

Memory Management

The printers use various methods to conserve and make the most of available memory. Several of these are explained below. Note LaserJet 4P/4MP: If the printer encounters diffkulty in managing available memory, a “Clearable Warning” message will be displayed on the front control panel. See “Clearable Warnings” in Chapter 7 for details. Memory Enhancement technology (MEt) HP’s Memory Enhancement technology (MEt) effectively doubles the printer’s standard memory through a variety of font and data compression methods. MEt also automatically compresses fonts for desktop publishing applications. When printing graphics, MEt analyzes each page as it is being printed and automatically applies a variety of methods to print the complete page at the correct resolution. Two of these methods, Image Adapt and Page Protect, are user-selectable through HP Explorer’s Remote Control Panel (Printer Memory Category). Note MEt is only available in PCL mode; it is not functional when printing in PostScript mode. 5-19, Functional Overview Formatter System Image Adapt (LaserJet 4L/4ML) Image Adapt uses a compression technique to allow printing of full-page graphics using the printer’s base memory. The available settings are Auto, On, and Off. The default setting is Auto. Some data may be lost if Image Adapt is used. To see if there has been some loss of graphic detail, print a self test page and check the “Image Adapt Used:” line in the Printer Information section of the page. If the printer invoked Image Adapt since the last time the self test was printed (or the last power cycle), that line will read “Image Adapt Used: Yes.” Note LaserJet 4L/4ML: The Image Adapt information on the self test page resets every time the self test page prints, or the printer is disconnected from its power source. Page Protect A page’s complexity (rules, complex graphics or dense text) may exceed the printer’s ability to create the page image fast enough to keep pace with the engine’s printing process. If a page is too complex, it may print in parts (for example, the top half of data on one page and the bottom half on the next page). Some print data loss is likely in these instances, and the printer’s Error light flashes. Page Protect allows the Formatter to create the entire page image in memory before physically moving the paper through the printer. This process ensures that the entire page will be printed. Page Protect is user selectable through HP Explorer’s Remote Control Panel (Printer Memory Category). The default setting is Auto. 5-20, Functional Overview Formatter System PJL Overview Printer Job Language (PJL) is an integral part of configuration, in addition to the standard Printer Command Language (PCL). (See “PJL Software Commands” in Chapter 3 for more information.) With standard Centronics cabling, PJL allows the printer to perform functions such as: . Two-way communication with the host computer through a Bi-directional Parallel connection. The printer can tell the host such things as the control panel settings, and allow the control panel settings to be set from the host. ● Dynamic I/O switching (LaserJet 4ML/4P/4MP) allows the printer to be configured with a host on each I/O. The printer can receive data from more than one I/O simultaneously, until the buffer is full. This can occur even when the printer is offline. Note The Serial and LocalTalk I/Os share the same softare interrupt. Thus, dynamic 1/0 switching is limited to switching between the parallel interface and one other I/O interface selected from serial and LocalTalk. ● Context-sensitive switching (LaserJet 4ML/4P/4MP only) allows the printer to recognize automatically the personalities (PostScript or PCL) of each host and configure itself to serve that personality. ● .Isolation of print environment settings from one print job to the next. For example, if a print job is sent to the printer in landscape mode, the subsequent print jobs print in landscape only if they are formatted for landscape printing. 5-21, Functional Overview Image Formation System

Image Formation System

Laser printing requires the interaction of several different technologies (such as electronics, optics, and electrophotographics) to provide a printed page. Each process functions independently and must be coordinated with all other printer processes. The image formation process consists of six stages: 1. Cleaning 4. Developing 2. Conditioning 5. Transferring 3. Writing 6. Fusing The toner cartridge houses the cleaning, conditioning, and developing stages of the process. Components of the image formation system that wear, degrade, or are consumed are built into the replaceable cartridge. The toner cartridge contains the photosensitive drum, primary charging roller, developing station, toner cavity, and cleaning station. This eliminates the need for a service call when replacement is required. Electrostatic latent image formation block . ..._.._, ~a:::mro’ block ~.-.-. gure 5-8 image Formation BIocK Diagram 5-22, Functional Overview Image Formation System Photosensitive Drum The photosensitive drum is the “heart” of the Image Formation System. The special properties of this drum allow an image to be formed on the dram’s surface and then transferred to paper. The drum is an extruded aluminum cylinder. The outside of the cylinder is coated with a layer of organic-photoconductive material (01’C) which is non-toxic. The aluminum base of the photosensitive drum is electrically connected to ground potential (s~e Figure 5-9). “.-,:

A‘“.;..,, Photosensitive\ ‘;;. Layer.::~~~ Aluminum...”. Base

Figure 5-9 Photosensitive Drum 5-23, Functional Overview Image Formation System Drum Sensitivity The OPC material has properties similar to a photo-resistor. It becomes electrically conductive when exposed to light. When the photosensitive drum is exposed to light, the negative charges deposited on it are conducted to the ground potential of the drum’s base. Areas not exposed to light remain nonconductive and maintain their negative charge. CAUTION - The printer’s toner cartridge does not include a light blocking shutter. Be careful to avoid exposing the drum to light, which can permanently damage the drum. Protect the cartridge whenever removing it from the printer, preferably by inserting it into the protective bag — from its packaging. t area I primary I ScanninTg Transfer ~rim~

I charging exposure charging1

- - .-. .. FigUre 5-1 U Drum Surtace Potential 5-24, Functional Overview Image Formation System

Cleaning Stage

During the cleaning stage of the image formation process, the drum’s surface is physically cleaned, preparing it to hold an image. During printing, the drum is rotating constantly making several complete rotations per printed page. Before forming the image for a given section of print, a cleaning blade removes toner from the previous rotation of the drum. The excess toner is stored in the toner cartridge where it is prevented from being used in later print jobs (see Figure 5-11). Cleaner container Cleaning blade \ Sweeper strip Figure 5-11 Drum Cleaning 5-25, Functional Overview Image Formation System

Conditioning Stage

After the drum is physically cleaned, it must be conditioned. This process consists of applying a uniform negative charge on the surface of the drum with the primary charging roller, located in the toner cartridge. The primary charging roller is coated with conductive rubber with an ac bias applied to erase any residual charges and maintain a constant drum surface potential. In addition, a negative de bias is applied by the charging roller to create a uniform negative potential on the drum’s surface. The amount of de voltage is modified by the print density setting. igure 5-12 Primary Charging Roller ● 5-26, Functional Overview Image Formation System

Writing Stage

At the writing station, the laser beam is used to discharge the photosensitive drum’s negative potential by focusing laser light onto its surface. This creates a latent electrostatic image, which later is developed into a visible image. Laser light is produced by a small modulated laser diode. The beam created by the diode shines onto a rotating polygonal mirror. As the mirror rotates, the beam reflects off the mirror and sweeps the page from left to right (see Figure 5-13). Bi-tronics 1/0 r————————- —$ ——_ _, I Formatter PCA I

I

I —— ———/BD /VDO — —-~ f-i - DC Controller PCA — /BD1 /VDOUT APCSH /SCNON LaserlScanner Photosensitive FlgWre5-13 Image Writin{g 5-27, Functional Overview Image Formation System A set of lenses and mirrors focuses the horizontal sweeping beam through the laser beam access slot in the rear of the toner cartridge, and onto the photosensitive drum. Because the beam is sweeping the entire length of the drum and the drum is rotating, a the entire circumference of the drum can be covered. The speed of the scanner motor (which turns the scanning mirror) and the speed of the main motor (which turns the drum) are synchronized, and each successive sweep of the beam is offset l/300th (or l/600th) of an inch. The beam can be turned on and off to place ● a dot of light every l/300th (or l/600th) of an inch in the horizontal direction. This is how the printer achieves its 300x 300 dpi (or 600 x 600 dpi) resolution. At the beginning of each sweep (before the beam reaches the drum), the beam is reflected off the beam detect mirror. The momentary pulse of light is sent to the DC Controller, where it is converted to an electrical signal used to synchronize the output of data (VDO) for one sweep (scan line). This pulse, referred to as the Beam Detect signal (BD), is used to diagnose problems with the laser diode or scanner motor. After the writing station, the drum surface has an invisible (latent) electrostatic image. Portions of the drum not exposed to the laser are still at the uniform negative potential (placed there by the primary charging roller), but those portions exposed to light have been discharged to ground, to form the latent electrostatic image. 5-28, Functional Overview Image Formation System

Developing Stage

The developing station develops the latent electrostatic image into a visible image on the drum. The developing unit consists of a metallic cylinder that rotates around a freed magnetic core inside the toner cavity. Toner is a powdery substance made of black plastic resin bound to iron particles, which is attracted to the magnetic core of the cylinder. A rubber blade “brushes” the toner on the developing cylinder to a uniform thickness. The toner particles obtain a negative surface charge by rubbing against the developing cylinder which is connected to a negative dc supply. The negatively charged toner is attracted to the discharged (grounded) areas of the drum exposed to laser light, and repelled from the negatively charged (non-exposed) areas. An ac potential is applied to the developing cylinder to decrease the attraction between the toner and the magnetic core of the cylinder, and to increase the repelling action of toner against the areas of the drum not exposed to laser light. This ac potential improves density and contrast (see Figure 5-14). ! II ~.. Ph w~ AC bias Developing cylinder DC bias 7“

A

F,...-.”, nnage u-,i-qure 3-14 eveloprnenl 5-29, Functional Overview Image Formation System The dc bias of the developing cylinder is adjusted to change the force of attraction between the toner and drum by changing the print density setting (from the front panel or through software). A change in dc bias causes either more or less toner to be attracted to the d~um, which in turn either increases or decreases the print density. The print density variation is approximately t 10% (see Figure 5-15). Both the primary and developer dc bias voltages are changed in response to the density setting. Developing cylinder surface potential Drum surface f +V potential -0 (exposed area)- - - - /’ 2 —- .— % -... -:- -ocbias s ~ -v \ Drum surface & Time t -D potential (unexposed area) Figure 5-15 Developing Potentials a 5-30, Functional Overview Image Formation System

Transferring Stage

At the transferring station. the toner image on the drum’s surface is transferred to tfie paper: A positive cha~ge applied to the back of the paper by the transfer roller causes the negatively charged toner on the drum’s surface to be attracted to the page. The small radius of the drum, combined with the stiffness of the paper causes the paper to peel away from the drum. The Static Eliminator also helps separate the paper from the drum. The Static Eliminator weakens the attractive forces between the negatively charged drum surface and the positively charged paper. Without this help, thin paper can wrap around the drum. After separation, the paper moves to the fusing station and the drum rotates to the cleaning and conditioning stations.

H I Static chargaeliminator Jf Tranafer charging roller I

Figure 5-16 Transferring Stage 5-31, Functional Overview Image Formation System

Fusing Stage

At the fusing station, the toner is fused into the paper by heat and pressure to produce a permanent image. The paper passes between a ceramic heating element protected by a thin, Teflon sleeve and a soft pressure roller. This melts the toner and presses it into the paper. The ceramic heating element comes up to fusing temperature very quickly, and thus does not require any power while the printer is on STANDBY. These are the first Hewlett-Packard LaserJet printers to employ this “instant-on” fusing system. Other laser printers use a halogen heating lamp and require frequent warming to maintain a minimum standby temperature. This feature saves power while virtually eliminating the warm-up period. The fusing temperature is monitored by the DC Controller PCA, using a thermistor (TH901). The DC Controller maintains a temperature of about 180° C during print mode. If the fusing svstem overheats (about 215° C), a relay o~ens the Dower circuit to the fusing heater, causing a Fuser Erro~ message. if the fusing system exceeds 240° C, the thermal fuse will open, cutting off power to the fuser. Fusin‘9’’’”-!3/:::::,,,.,., - Toner ./., \ \Y” Paper

T< Pressure

F Roller — -.— — -.. Figure 5-17 Fusing Film and Pressure Roller 5-32, Functional Overview Paper Feed System

Paper Feed System

● The following topics are discussed in this section: Paper Movement Overview Solenoids Photosensors Paper Out Sensor Input Paper Sensor Printing from the Paper Cassette Printing from Manual Feed Paper Jam Detection ● 5-33, Functional Overview Paper Feed System

Paper Movement Overview

The paper feed system picks print media automatically from the paper cassette or accepts it from the manual feed slot and delivers it to the image formation system at precisely the right time. The ● system then feeds the media to the fusing station, and delivers the finished n. roduct to the outmt .~osition. either the face-down output tray on top of the printer, or through the face-up delivery slot at the rear of the printer. The output path is user-selectable by turning the paper path knob on the rear of the printer. ● Figure 5-18 shows the possible paper paths and locations of the various solenoids, photosensors and rollers. I OC Controller PCA I

YY

‘Cassette Feed Paper Path Paper Cassette .—. .- Figure 5-18 Printer Paper Path PSI Input Paper Sensor Input Paper Sensor (PSI ) Positions: PS2 Paper Out Sensor A = Manual Feed Sense Position PS3 Exit Paper Sensor B = Registration Sense Position PS4 Whaling Paper Sensor C = TOP Sense Position 5-34, Functional Overview Paper Feed System

Solenoids

Table 5-1 Solenoids No. Name Description SLI Paper Feed Solenoid Located in the Pickup Roller Assembly, and (Registration) controls the registration rollers. SL2 Pickup Solenoid Located on the DC Controller, and controls the Picku~ Feed D-Roller,

Photosensors

Table 5-2 Photosensors Name I Description Psl Input Paper Sensor Four-position photosensor. Senses manual feed and paper at registration position. PS2 Paper Out Sensor Senses empty paper cassette,

I PS3 Exit Paper Sensor Senses paper exiting the fuser rollers. I PS4 Winding Paper Sensor Senses paper in the paper feed guide area.

Paper Out Sensor (PS2) The Paper Out Sensor (PS2) detects the presence of paper in the ● cassette. If no paper is sensed in the cassette, the Formatterdisplays the paper-out indication on the front panel (display panel message or Paper light). The cassette must be reloaded before printing can resume. 5-35,

Functional Overview Paper Feed System Input Paper Sensor (PSI)

The Input Paper Sensor, PSI, is a four position sensor that detects paper in the Manual Feed Sense Position, the ‘“” Registration Position, and the Top Position. The figure to the left shows the Manual Feed and Cassette paper paths. The figures below show the sensor in each of the four positions. Registration The Ready or Wait/Standby Position arm indicates that paper has not entered the paper path. @ Input Paper

WAIT Sensor (PSI )

(STBY) The Manual Feed Sense Position (A) indicates that paper has either been inserted into the manual feed slot or has been picked from the paper cassette and reached this position in the paper path.

A The Registration Position (B) signals

the DC Controller to monitor if the scanner motor is up to speed and the fuser is at the correct temperature. When both conditions are met, the paper continues to the Top Position. If these conditions have not been met, solenoid SL1 is engaged to stop the registration roller until the printer is ready. When the printer is ready, SL1 disengages and paper proceeds to the Top Position. The Top Position (C). When paper paeses through the Top Position, the DC Controller sends a signal to synchronize the image on the photosensitive drum with the top of the page. 5-36, Functional Overview Paper Feed System

Printing from the Paper Cassette

Paper motion begins when the DC Controller PCA, after receiving a PRINT signal, starts the Scanner Motor, the Main Motor, and the fusing heaters. The Pickup Solenoid (SL2) is energized for 0.5 seconds, the pickup roller and the registration roller rotate and feed a sheet of paper from the Paper Cassette to the Registration Position, where the registration roller is stopped by solenoid SL1, if necessary, until the Scanner and Fuser are ready. While the registration roller is rotating, the oblique rollers are aligning the paper’s left edge correctly to prevent skewing (see Figure 5-19). Left side of ~ the main unit t ... Paper Figure 5-19 Oblique Roller Paper Alignment The Formatter PCA sends the VDO signal to the print engine within a specified amount of time after the Input Paper Sensor (PS1) reaches the Top Position. The leading edge is now aligned, ready to proceed under the photosensitive drum. After the paper passes under the drum, past the Winding Sensor (PS4), and through the fusing unit, it triggers the Exit Paper Sensor (PS3). The paper is then fed through either the face-up delivery slot or the face-down output rollers and to the top output tray, depending on the position of the face-up deflectors. 5-37, Functional Overview Paper Feed System

Manual Feed Printing

The presence of paper in the-manual feed slot is detected when the Input Paper Sensor (PSI) reaches the Manual Feed Sense Position. The Manual feed system’s paper motion begins when the a DC Controller PCA, after receiving a PRINT signal, starts the Scanner Motor, the Main Motor, and the fuser heating element. The Registration Solenoid (SL1) is OFF at this time, allowing the registration roller to rotate. This feeds the paper from the Manual Feed slot to the Registration Position. ● The remainder of the manual feed print process is identical to the cassette feed process, described above.

Small Media Rollers (LaserJet 4P/4MP)

The LaserJet 4P/4MP has an additional set of Small Media Rollers, located midway between the pickup and delivery rollers (see Figure 5-18). These rollers allow the printer to accept a smaller minimum paper size: 3x5inches (76x 127 mm). ● 5-38, Functional Overview Paper Feed System

Paper Jam Detection

The Input Paper Sensor (PSI), Paper Exit Sensor (PS3), and the ● Winding Paper Sensor (PS4) detect when paper is moving throughthe printer (see Figure 5-18 for sensor locations). If a paper jam is detected, the DC Controller immediately stops the printing process and causes a paper jam indication on the front panel. a A paper jam can be detected under any of the following conditions: Power-On Jams Paper is present under either PS1, PS4 or PS3 at power-on. Pickup Jams Paper does not reach and clear photosensor PSI within a specified period of time. For cassette feed the time period begins when the Paper Pickup Solenoid (SL2) is energized; for manual feed the time period begins shortly after PSI is moved into the Manual Feed Sense Position (position “A” under “Input Paper Sensor”). Delay Jams Paper does not reach or clear a specific photosensor within a specified period of time. 5-39, Functional Overview Basic Sequence of Operation —

Basic Sequence of Operation

●

Standard Printer Operation

The Formatter PCA and the DC Controller PCA share information during printer operation. The DC Controller-to-Formatter Connector (DC Controller J201) forms a link which operates as a serial data bus. This allows printer status, command information, ● and dot-image data to be passed between the two PCAS. The following events take place during normal printer operation: Table 5-3 Print Period Descriptions (refer to Timing Diagram) PERIOD TIMING PURPOSE WAIT From power ON (power cord Clear the drum surface potential connection) to the end of Main and clean the Transfer Roller. Motor initial rotation.

I

STBY From the end of the WAIT or the IMaintain the printer in ready state, (Standby) LST~od until the input of the PRNT signal from the Formatter. Or from the end of the LSTR period until power OFF. INTR From the input of the PRNT signal Stabilize the photosensitive drum (Initial from the Formatter until the laser sensitivity in preparation for Rotation) diode intensity has been stabilized. printing. Also clean the Transfer w= Roller.From the en=d of initial=rotation u=ntil Form=images on thephotosensitive drum based on the/VDO signal from the Formatter

I and transfer the imaue to ~a~er.

LSTR From the primary voltage (DC) Deliver the last sheet of paper. [Last OFF until the Main Motor stops. Also clean the Transfer Roller. Rotation) If another PRNT signal is sent from the Formatter, the printer returns to the INTR period. If not, it returns to the STBY period, 5-40, General Timing Diagram ● (Unit: second I LSTR STBY

I

1- 9.6 ● apporox. 1041010.81 FuSi I *I pR[,contml 4 MairI5scatII30.07 Pick d * Pap, I (SLI CJ~~~ + 1-002 in lnp~ -11- “ 4 k-02 ,, ExitIIvariable (Ps: 12 prim I , 13 Prirr

F14 Dev 0.7115 Dev16 Trar=w .1“48 -

5-41, a ● Removal and Replacement, Removal and Replacement Removal and Replacement Strategy

Removal and Replacement Strategy

This chapter documents removal and replacement of Field Replaceable Units (FRUS) only. Exchange assemblies should be sent to SMO for repair. Unless specifically stated otherwise, these procedures apply to all four printer models (LaserJet 4J-J4ML/4P/4MP). Replacement is generally the reverse of removal. Occasionally, notes are included to provide direction for diffkult or critical replacement procedures. WARNING! Unplug the power cord from the power outlet before attempting to service the printer. If this warning is not followed, severe injury may result. Never operate or service the printer with the protective cover removed from the Laser/Scanner Assembly. The reflected beam, although invisible, can damage your eyes. CAUTION The printer contains parts that are electrostatic discharge (ESD) sensitive. Always service printers at an ESD protected workstation. To install a self-tapping screw, first turn it counter-clockwise to align it with the existing thread pattern, then carefully turn clockwise to tighten. Do not over-tighten. If a self-tapping screw-hole becomes stripped, repair of the screw-hole or replacement of the affected assembly is required. Note Always remove the toner cartridge and the paper cassette from the printer before removing or replacing printer parts. 6-2, Removal and Replacement Required Took

Required Tools

#2 Magnetized Phillips Screwdriver (6-inch shaft) Small flat-blade Screwdriver Small Pair Needle Nose Pliers All screws used in the printer are Phillips head screws which require a #2 size Phillips screwdriver. Figure 6-1 shows the difference between a Phillips and a Pozidriv screwdriver. Note that the Phillips tip has more beveled surfaces. CAUTION A Posidriv screwdriver will damage the printer’s screw heads. Use Phillips only.

Phillips Posidriv

Flglm 5-’1 Phillipsvs. Posidriv Screwdrivers 6-3, Removal and Replacement User Installable Assemblies ●

User Installable Assemblies Memory Upgrade (LaserJet 4L)

The small access door on the left side of the winter allows access to the memory connector on the Formatter PCA. m CAUTION Memory modules must be removed prior to removing the Printer Cover to avoid possible damage ;O the memory, the Formatter PCA, or the DC Controller. 1. Open the Memory Door. 2. Pull outward on the small handle to unplug the memory assembly and remove. Figure 6-2 Removing the Memory Module (LaserJet 4L) 6-4, Removal and Replacement User Installable Assemblies

Memory/Language SIMMS (LaserJet 4P/4MP)

The SIMM slots are under an access panel on the left side of the ● printer. Place the printer on a firmly supported, flat surface. 1. Push downward forcefully on top of the access panel to release its clips from the main Printer Cover (Figure 6-3, callout 1). ● 2. Remove any SIMM modules (release side clips, tilt upward and lift out carefully). clAL!-l-lo N SIMM modules must be removed prior to removing the Printer Cover to avoid damage. Figure 6-3 Removing the SH’JM Access Panel (LaswJet 4P/4NlP) Tore-install: SIMM module can be installed in any available slot. Sequence is irrelevant. Install with the small notch toward the left. To re-install the access panel, hold it in place and lift firmly upward on the thumb grip (Figure 6-3, callout 2) to snap into place. 6-5, Removal and Replacement Cover and Doors

Cover and Doors

●

Power, I/O and Memory Doors (LaserJet 4L/4ML)

The Power Door is located on the right side of the printer. The I/O Door and Memory Door are on the left side (refer to Figure 1-2). Some doors are not hinged; and are removed simply by opening. Others (such as the Power Door) have a small hinge tab which a holds the door in place. To remove the Power Door: 1. Open the door to a 90 degree angle. 2. Push the upper tab down slightly and tilt the door out (Figure 6-4). Figure 6-4 Removing the Power Access Dcmr (LaserJet 4L/4ML) 6-6, Removal and Replacement Cover and Doors

Printer Cover (LaserJet 41J4ML)

1. Remove the Power Door and unplug the power cord (Figure 6-4). ● 2. Remove the toner cartridge and paper cassette. 3. Remove any optional memory card (Figure 6-2). ● CAUTION Step 3 is critical to avoid darnage to the memory card, the Formatter PCA, and the DC Controller. 4. Unplug the parallel cable. 5. Remove the (4) self-tapping printer cover screws (Figure 6-5, callout 1). Figure 6-5 Fbncwing W Prinkr flow Screws (LaserJet 4L/4ML) (continued on next page) 6-7, Removal and Replacement Coverand Doors 6. With the Rear Door open, pull the lower rear tabs outward, away from the printer and lift upward slightly (Figure 6-6). Figure 696 Releasing the Printer !XIwr Flew Tabs 7. Place a small object under the rear of the cover to keep it from snapping back in place. Pull the front lower front tabs outward, away from the printer chassis as in step 6 above. 8. Grasping the front and rear, lift the cover straight up, being careful to not catch any other assemblies while lifting. CAUTION Avoid holding the cover by the more flexible left and right sides. Be careful to avoid catching the green Fuser Release Tab at the rear of the printer while lifting the cover off. Tore-install: When reinstalling the Printer Cover, be sure the rear door is open. Lower the cover straight downward to avoid catching any parts. 6-8, Removal and Replacement Cover and Doors ●

Printer Cover (LaserJet 4P/4MP)

1. Unplug the power cord and interface cable(s). ● 2. Remove the toner cartridge and paper cassette. CAUTION Steps 3 and 4 are critical to avoid damage to the ● SIMMS, the Formatter PCA, and cabling. 3. Remove the SIMM access panel and any installed SIMM modules (Figure 6-3). 4. Unplug the front panel cable connector (to the right of the topmost SIMM slot on the Formatter PCA - Figure 6-7). m F@m: &7 C.WWOPI anelConnector bxdcm (LaserJet 4W41W) ● (continued on next page) 6-9, Removal and Replacement Cover and Doors 5. From the top of the printer, remove the (4) self-tapping screws (Figure 6-8, callout 1) and one machine screw (callout 2). 6. From the front of the printer, remove the one machine screw with star washer (Fi@re 6-8: callout 3). (continued on next page) 6-10, Removal and Replacement Cover amd Doors 7. Turn the printer around so that the back edge hangs slightly beyond the edge of the table. Open the printer’s rear door. 8. Pull outward on the two rear cover tabs to release pressure and lift slightly. Be sure to pull outward enough to clear the ac power receptacle (Figure 6-9, callout 1). 9. Reaching through the access hole (Figure 6-9, callout 2), pull outward to clear the power switch. 10.Turn the m-inter around and mdl outward on the two front cover tab; to release pressure’ while lifting (Figure 6-9, callout 3). Once all cover tabs are free and the ac input and power switch are clear, lift the cover straight up carefully. Jre 6-!3 Fkwrmving W Cover (Laserdet 4P/4MP) Tore-install: Ensure that the power switch is fully seated in its retaining slot. When lowering the cover over the chassis, be careful not to snag the parallel port bail lock (left rear), the ac power input (right rear), or the power switch. Watch positioning of the front cover tabs and the control panel cable. Re-connect the control panel cable and replace any SIMM modules that were removed. 6-11, Removal and Replacement Cover and Doors

Rear Door

The Rear Door provides access to the fuser area. The door is held in place by two flexible plastic tabs which mount into a groove on the rear of the Printer Cover. 1. Remove the Printer Cover and turn it upside down. 2. With the Rear Door o~en, ~entlv bend the tab inward and down to release (Figure 6-16). ‘ = “ Figure 6-10 Removing the Rear Door 6-12, Removal and Replacement Cover and Doors

Control Panel (LaserJet 4P/4MP)

1. Remove the Printer Cover and turn it upside down. 2. Remove the (3) machine screws (one with star washer) (Figure 6-11, callouts 1 and 2). 3. Lift the Control Panel Assembly and unplug the connector from the PCA.

I

Figure 6-11 Removing Ilw ControPl anelAssembly(LaserJc44P/4MP) (continued on next page) 6-13, Removal and Replacement Cover and Doors 4. Remove the three self tapping RFI shield screws (Figure 6-12, callout 1) and one machine screw (callout 2). 5. The Control Panel PCA is located under the RFI shield. F%@%6-”!2 Cmin’ii’cRll3nd w=!SMeld(!-asErJ’e’Wi V4WT) To re-instalk Before reassembly, ensure that the control panel cable is properly routed within its cable guides. 6-14, Removal and Replacement M Side Assemblies

Left Side Assemblies Formatter Shield and PCA

The Formatter PCA is located under a metal RFI shield on the left side of the printer. PAl UT Bf3?J Use mo~er ESD m-ecautions when removing the $4 Fiuniwzv For&at~er PCA. Avoid touching component; and use an anti-static bag for storage or ~hipping. 1. Remove the Printer Cover. 2. Remove the screws that hold the RFI shield in place and lift the shield off (Figure 6-13, callout 1 for LaserJet 4L). 3. Remove any remaining screws on the Formatter PCA (Figure 6-13, callout 2 for LaserJet 4L). Figure6.13 Removing the Fcwnatler Shield and K’%A(Laserkt M shown) 6-15, Removal and Replacement Left Side Assemblies 4. Grasp the Formatter PCA near the center and. pull straight out (the PCA is plugged into the DC Controller through the connector in the lower center area). h[nf@ When replacing the Formatter PCA, remove and transfer the Formatter to DC Controller Connector Extension (all printers) and the Switch Actuator (LaserJet 4L/4ML) to the new . PCA. Procedures are shown below. 5. To remove the connector extension, squeeze the tabs on either side and pull the Extension straight out the rear of the PCA (Figure 6-14, callout 1). 6. LaserJet 4L /4ML: Saueeze the tabs on the Switch Actuator and 6-16, Removal and Replacement Left Side Assemblies

Gear Train Assembly

The Gear Train Assembly is located on the left side of the printer, under the Formatter PCA. The steps and pictures here are for the LaserJet 4L/4ML. The LaserJet 4P/4MP is slightly larger but very similar. 1. Remove the Printer Cover and Formatter PCA (Figure 6-13). 2. Loosen (do not remove) the (2) upper self-tapping Main Motor screws (Figure 6-15, callout 1), 3. Through the access holes (Figure 6-15, callout 2), remove the (2) screws securing the Gear Train grounding springs (small diameter machine screws with captive star washers). These screws are connected to the DC Controller Assembly. 4. Remove the (6) self-tapping screws (Figure 6-15, callout 3). 5. Pull the Gear Train Assembly straight out to remove. Keep the gear side of the assembly face up (g=ars are held in place by light pressure only and may fall off if the assembly is tilted). Figure 6-15 Removing the Gear Train Asswnbly (bswJet 4Lshcwm) (continued on next page) 6-17, Removal and Replacement LeffSide Assemblies To re-instalh 1. Maneuver the assembly back in place, rotating some of the gears slightly to mesh, if necessary. ,0 2. Tighten the screws beginning in the center and working outward (Figure 6-16). a CA!JTION Do not tighten the upper two Main Motor screws until the Main Motor and Gear Train are both in place. Tightening the screws without the Main . Motor in place can damage the mount. P ! Figure 6-16 Screw Tightening Sequence Example (Lase\rJe’i 4P shown) ● 6-18, Removal and Replacement Left Side Assemblies

Main Motor

a 1. Remove the Printer Cover, and the Formatter Shield and PCA(Figure 6-17). 2. Remove the (1) machine screw through the access hole on the Gear Train Assembly, approximately two (2) inches below the top of the Main Motor (Figure 6-17, callout 1). ● 3. Remove the (2) self-tapping screws at the top of the Main Motor and pull the Main Mo{& s~raight up and out (Figure 6-17, callout 2). 6-19, Removal and Replacement Front Assemblies

Front Assemblies Front Oblique Roller Assembly

The Front Oblique Roller Assembly is located on the front of the printer, and is accessible after removing the Paper Cassette. It can be removed without removing the Printer Cover. 1. Remove the Paper Cassette. 2. Remove the (1) self-tapping screw on the left of the Front Oblique Roller Assembly and tilt the assembly out at the bottom to remove (Figure 6-18, callout 1). Figure 6-l El Removing the Oblique Roller Assembly 6-20, Removal and Replacement Front Assemblies

Paper Cassette Assembly

Field replaceable parts on the Universal Paper Cassette include: the Tray Forms Size Guide(s), two compression springs. Tray Forms Size Guide (LaserJet 41J4ML) Note The forms size guides on the LaserJet 4P/4MP are very easily removed and are not shown here. 1. Remove the Paper Cassette from the printer and unload paper. 2. Slide the guide all the way to the left and forward (near the “B5” adjustment line). 3. Lift the inside corner up slightly while twisting the guide in a clockwise direction. This frees the tab on the back side of the cassette, allowing removal. Figure 6-19 Rwmvkj theTray Forms Size Guide (LaserJet 4L/4ML shown) 6-21, Removal and Replacement Front Assemblies Compression Springs The Paper Cassette compression springs are located under the large pressure plate. The LaserJet 4L/4ML is shown here. Removal procedures for the LaserJet 4P/4MP are very similar. a 1. Remove the Paper Cassette from the printer and unload paper. 2. Release the plastic latch on the lower left corner of the cassette a assembly (Figure 6-20). Rotate the metal bar up and out of the way. 3. Release the large pressure plate from the catches on both sides (LaserJet 4L/4ML only). Raise the plate all the way up to access the compression springs. ● Tore-install: Before lowering the pressure plate back into place, be sure that the larger compression spring on the left side will be seated properly on the underside of the plate. ● 6-22, Removal and Replacement Internal Assemblies

Internal Assemblies Laser/Scanner Assembly

1. Remove the Printer Cover. 2. Lift the foam cover and unplug the Fan connector (Figure 6-21, callout 1). (The Fan’s power is via the Laser/Scanner Assembly.) 3. Remove the (3) self-tapping screws (Figure 6-21, callout 2). Note The uppermost screw in Figure 6-21, callout 2, is under a protective light shutter, Do not remove the scanner cover screw (crossed circle in Figure 6-21). There are no field replaceable parts inside the Laser/Scanner Assembly. 4. Lift the Laser/Scanner Assembly at both ends to remove (there may be some connection resistance - Figure 6-21, callout 3). Figure 6-21 Removing the Laser/Scanner Assembly 6-23, Removal and Replacement Internal Assemblies

Fan

1. Remove the Printer Cover. 2. Lift the foam cover and unplug the Fan connector from the Laser/Scanner Assembly (Figure 6-21, callout l). 3. Pull down on both sides of the plastic bottom tab (use a flat-blade screwdriver on the LaserJet 4P/4MP) and tilt the bottom of the fan outward (Figure 6-22, callout 1). 4. With the bottom tab released, pull upward on the top tab to 6-24, Removal and Replacement Internal !ksemblies

Power Switch Assembly (LaserJet 4P/4MP only)

The Power Switch assembly is mounted on the right side of the printer chassis, below the fan. 1. Remove the Printer Cover. 2. Remove the (3) self tapping screws (Figure 6-23, callout 1). 3. Remove the (2) machine screws (Figare 6-23, callout 2), and pull the Power Switch Assembly outward to unplug from the DC Controller. To access the second machine screw, it maybe necessary to re-seat the power switch fully downward in its retaining slot (if it was dislodged during cover removal). 6-25, Removal and Replacement Internal Assemblies

Paper Guide/Top Oblique Roller Assembly

The assembly is held in place by one self-tapping screw, two plastic alignment tabs, and a plastic latch tab. ● Note It is not necessary to remove the Printer Cover, although the front alignment tabs (Figure 6-24, callout 2) are more easily accessible with the cover removed. a 1. Remove the (1) self-tapping screw on the left side of the assembly (Figure 6-24, callout 1). 2. Lift the rear of the assembly while pushing down at the front, and pull it to the rear slightly (this releases the tabs - Figure 6-24, callout 2). $?jJ-J -“ Figure 6-24 Removing the Paper Guide/Roller Assembly Tore-install: Ensure that the Guide Assembly is under the top door release button plunger and that the two tabs are in place. ● 6-26, Removal and Replacement internal Assemblies

Transfer Roller and Guide

The Transfer Roller is located inside the top door, under the toner cartridge. The Printer Cover does not need to be removed to a replace the Transfer Roller. CAUTION Do not touch or otherwise contaminate the ● surface of the Transfer Roller. Skin oils andother contaminants affect its electrical characteristics, resulting in poor image transfer. 1. Open the top door and remove the toner cartridge. 2. Using a flat-blade screwdriver, gently pry under the left end to lift the roller shaft upward (Figure 6-25, callout 1). Figure 6-25 Replacing Me Transfer Roller ● (continued on next page) 6-27, Removal and Replacement Internal Assemblies 3. Lift the Transfer Roller and Guide slightly and slide toward the left to remove. Do not lift the roller more than about 1 inch (2.5 cm) before sliding it out of the right bushing. 4. Pull the Roller shaft out of the clips on the Transfer Roller Guide to release the Transfer Roller from the Guide. — Note If replacing just the Transfer Roller Guide, be careful not to lose the Transfer Roller gear. It is only held in place by slight pressure and can fall — off the Roller shaft. Tore-install: Install the right end first. Ensure that the tabs are seated firmly in place below the plastic guide (Figure 6-25, callout 2), and push the Transfer Roller into place. Transfer Roller Bushings The Transfer Roller Bushings are located under the left and right ends of the Transfer Roller (refer to Figure 6-25). It is not necessary to remove the Printer Cover to replace the bushings. 1. Open the top door and remove the toner carttidge. 2. Remove the Transfer Roller (Figure 6-25). 3. Remove the (1) self-tapping screw and lift the bushing straight out (the same procedure applies for both the left and right bushings). 6-28, Removal and Replacement internaAlssemblies

Beam-to-Drum Mirror Assembly

● Nclie Be carefi.d not to touch the surface of the mirroron the underside of the assembly. If the mirror does get contaminated, use filtered, compressed air to clean. If still dirty, clean it carefully using lens cleaner and a lint free cloth or swab. ● “ 1. Remove the Printer Cover. 2. Note where the mark on the printer chassis aligns with the graduated scale on the mirror (Figure 6-26, callout 1). 3. Remove the (2) self-tapping screws (Figure 6-26, callout 2). Grasp the mirror assembly by the sides only, and lift to remove. Figure 6-26 %m=m‘willsnBegam.to.lclrum Mirror Tore-install: Install in the correct alignment as noted in step 2. Check adjustment according to the “Beam-to-Drum Mirror Adjustment” procedure in Chapter 7. 6-29, Removal and Replacement Rear Assemblies a

Rear Assemblies Fusing Assembly

1. Remove the Printer Cover. 2. Remove the machine screws with star washers (1 on 4LJ4ML, 2 on 4P/4MP) (Figure 6-27, callout 1). a 3. Remove the (2) self-tapping screws (Figure 6-27, callout 2). 4. Slide the Fusing Assembly straight out from the rear of the unit (some resistance may be encountered because of the two connectors to the DC Controller). ) 1 Figure 6-27 Removing the Fusing Assembly (Laser&?t 4P shown) 6-30, Removal and Replacement Rear Assemblies

Fusing Assembly Components

The following procedure describes the steps for disassembling the Fusing Assembly (after it has been removed from the printer). Please perform the steps in the sequence listed. Pressure Plate CAUTION Do not remove or disturb the (2) stationary compression springs located at either end on top of the pressure plate. Dislocation of these springs can cause poor fusing. 1. Remove the spring from each end of the Pressure Plate (Figure 6-28, call&t 1). 2. Open the Pressure Plate more than 90 degrees and lift it off its 6-31, Removal and Replacement Rear Assemblies Upper Fusing Assembly (Teflon Sleeve and Heater Element) 1. Unsnap and open the cable clip shown in Figure 6-29, callout 1. 2. Remove the wires from the open cable clip and gently squeeze the connector to unplug. 3. Unplug the second connector shown in Figure 6-29, callout 2. 4. Squeeze the tab on the ceramic heater element connector and pull the connector free (Figure 6-29, callout 3). 5. Grip both ends of the Upper Fusing Assembly, lifting it out. Figw’e 6=29 Rwnoving‘MeuppewringAssembly 6-32, Removal and Replacement Rear Assemblies Pressure Roller ● ’NOTE The plastic bushings under each end of thePressure Roller can fall out of place and be easily lost. 1. The Pressure Roller is now free. Grasp both ends and lift it out. ● Delivery Assembly 1. Pull out gently on the metal frame on either end of the Delivery Assembly to release the mounting pins. Lift the assembly out (Figure 6-30). Figure 6-30 Removing the F’user Delivery Assembly ● Tore-install: Ensure that the assembly is installed with its white plastic pressure rollers toward the back of the Fusing Assembly, adjacent to the Lower Delivery Rollers. It is possible to ● install the Delivery Assembly backwards. 6-33, Removal and Replacement Rear Assemblies Lower Delivery Roller 1. Lift up on the bushing tab and slide the shaft inward and out of the bushing (Figure 6-31, callout 1). 2. Slide the bushing out from the metal frame and slide the Lower Delivery Roller out (Figure 6-31, callout 2). Fic.y,mi+6-31 Removing H-KI?LcmwDelivery !%lkr ● 6-34, Removal and Replacement Rear Assemblies Lower Delivery Guide/Exit Sensor Flag 1. Slide the Lower Delivery Guide slightly back to clear the center tab and lift the guide out, being careful not to damage the Exit @ Sensor Flag. Tore-install: Be certain to install Exit Sensor Flag into its groove (Figure 6-32). 6-35, Removal and Replacement Rea’Assemblies Connector Assembly (Fuser Entrance Guide) 1. Remove the connector wires from each end of the Comector Assembly (Figure 6-33, callout 1). o 2. Gently squeeze the cable clip tabs using needle nose pliers and slide the cable clip out of the frame (Figure 6-33, callout 2). 3. Remove the (1) machine screw (Figure 6-33, callout 3). 4. Slide the Connector Assembly toward the cable clip location and lift out. 17gurr?6-33 Flemovhmj the Fusw Connector Assembly Tore-install: Be certain to correctly align the wires that run inside of the ● Connector Assembly to avoid damage. 6-36, Removal and Replacement Rear Assemblies

Upper Output Roller Assembly

1. Remove the Printer Cover. ● 2. Using a flat-blade screwdriver, release the two-sided tabs from each end of the Roller Assembly (Figure 6-34). 3. Lift the Upper Output Roller Assembly out to remove. CAUTION Be carefid not to lift one end of the shaft more than about 1/2 inch (1 cm) before both ends have been released, as this will break the shaft. Figure 6-34 Removing the Upper Output Roller Assembly ● 6-37, Removal and Replacement Rear Assemblies

Lower Output Rollers

There are four-separate output rollers located directly below the Upper Output Roller Assembly. Each roller is held in place by three pressure tabs. @ 1. Remove the Printer Cover. 2. Remove the Upper Output Roller Assembly (Figure 6-34). e 3. Push either the left or right tab inward, tilt the Output Roller and lift upward to remove (Figure 6-35). Use the same procedure for all four rollers. Figure 6-35 Removing the Lower CMpwl Rollers 6-38, Removal and Replacement Bottom Assemblies

Bottom Assemblies DC Controller Assembly

The DC Controller Assembly is located on the bottom of the printer. The PCA is protected by a metal shield assembly, and is mounted to a plastic base. The Formatter PCA and Fusing Assemblies are connected directly into the DC Controller and must be removed prior to removal of the DC Controller Assembly. 1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), and the Power Switch Assembly (LaserJet 4P14ikTP only - Figure 6-23). Cliu-r[ah! Failure to remove all the above components before removing the DC Controller will result in printer damage. 2. Remove the (2) screws that attach the grounding springs to the Gear Train Assembly (Figure 6-36, callout 1). 3. Remove the (5) self-tapping screws and the (1) machine screw from the bottom of the DC Controller Assembly (Figure 6-36, callouts 2 and 3). Do not remove the Pickup Solenoid screw (crossed circle in Figure 6-36). 4. Push the Pickup Feed D-Roller solenoid arm in and rotate the D-Roller down, clear of the solenoid arm (Figure 6-36, callout 4). 5. Gras~ the rails on either side of the DC Controller Assemblv and fift the assembly out, being careful not to catch the sol&oid arm on the Pickup Feed D-Roller. (continued on next page) 6-39, Removal and Replacement Bottom Assemblies Note When removing the DC Controller Assembly there will be resistance where the connectors are attached (on the left in Figure 6-36). A firm tug may be necessary to free the assembly. Figure 6-36 Removing the DC Controller Assembly To re-instalh When reinstalling the DC Controller, be sure to use a short length (6 mm) machine screw at Figure 6-36, callout 3. A longer (10 mm) screw will obstruct the Fusing Assembly. Ensure that the PSI Input Paper Sensor Arm (Figure 6-51), and the PS2 Paper-out Sensor Flagon the D-Roller Assembly (Figure 6-41, callout 2) are in their proper positions. The Input Paper Sensor Arm should operate freely. If either of these are not seated properly, this will cause a continuous Paper Jam error condition. 6-40, Removal and Replacement Bottom Assemblies

Pickup Solenoid (SL2)

The Pickup Solenoid (SL2) is located on the DC Controller PCA, ● 1. Remove the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Fiare 6-13), and Power Switch Assembly (LaserJet 4P/4iWP &ly - Fig-&e 6-23), and the DC Contro~ler Assembly (Figure 6-36). ● 2. Remove the (1) machine screw holding the Pickup Solenoid from the lower side of the DC Controller Assembly (the crossed circle shown in Figure 6-36). 3. Unplug the Pickup Solenoid connector (Figure 6-37, callout 1) and remove the solenoid (Figure 6-37, callout 2). Note Be careful not to lose the small metal grounding tab that fits over the solenoid’s mounting post. 6-41, Removal and Replacement Bottom Assemblies e

DC Controller Fuses

There are two in-line fuses (one on 220 V units) on the component side of the DC Controller PCA (shown in Figure 6-37, callout 3). (The rated amperages are printed on the PCA.) Pull outward to ● remove.

High Voltage Connector Assembly

This assembly is mounted on the component side of the DC ● Controller PCA, and provides high voltage contact points to the toner cartridge (shown in Figure 6-37, callout 4). To remove, press the two tabs in on either side of the cover and lift it straight up and off. 6-42, Removal and Replacement Bottom Assemblies

DC Controller PCA

If the DC Controller PCA is to be replaced, the old PCA must first be removed from its mounting assembly. CAUTION The DC Controller PCA is ESD sensitive. Avoid using conductive tools (such as metal screwdrivers) when removing the DC Controller PCA from its mounting assembly. 1. Remove the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), and the Power Switch Assembly (LaserJet 4P/4MP only- Figure 6-23). 2. Remove the DC Controller Assembly (Figure 6-36), Pickup Solenoid, and High Voltage Connector Assembly (Figure 6-37). 3. Remove the (2) machine screws (Figure 6-38, callout 1). Figure6-38 MachineScrew I-ocatkms(IX ControllerlWA) (continued on next page) 6-43, Removal and Replacement Bottom Assemblies 4. Remove the metal backing plate by releasing pressure on the curved portion, then tilting the plate out (Figure 6-39). CAUTION – Be careful not to lose the metal grounding clip that is attached to the mounting plate (Figure — 6-40, callout 1). Figure6-39 Rmovhg the MkXaEl lackingIYak (continued on next page) ● 6-44, Removal and Replacement E)ommfl AS$emblk?s 5. Push the four plastic pressure tabs out to release (Figure 6-40, callout 2). 6. Squeeze the alignment pin together to release (Figure 6-40, callout 3). 7. Tilt the PCA outward at the top until it clears the lower two Figure 6-40 Removing the IX C%ntrcdler NY! Tore-install: After replacing the DC Controller PCA, be sure to set the leading edge registration. See “Leading Edge Adjustment” in Chapter 7. 6-45,

Pickup Feed D-Roller

Access to the Pickup Feed D-Roller requires removal of the DC Controller Assembly. The D-Roller itself can be removed without removing the entire Pickup Assembly from the printer. ● 1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), the Power Switch Assembly (LaserJet 4P/4MP only- Figure 6-23), and the DC @ Controller Assembly (Figure 6-36). 2. Lift upward on the pressure clip (Figure 6-41, callout 1) and slide the D-Roller off the shaft. - - Tore-install: 1. Position the photosensor flag arm (callout 2) out of the way. 2. Apply pressure on the opposite end of the roller shaft (callout 3). ● 3. Push the D-Roller onto the shaft until it “clicks” into ~lace. 4. After replacing the D-Roller, power-on the printer wi~hout the paper cassette in place to cause the roller to rotate into the cotiect initial pos;tion. 6-46, Removal and Replacement IEMk$m A!sse[’mks

Pickup Assembly

1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), o the Formatter Shield and PCA (Figure 6-13), the Power Switch Assembly and Font Cartridge Bracket (LaserJet 4P14MP only- Figure 6-23 and 6-16), and the DC Controller Assembly (Figure 6-36). ● ~~:(~ Although not mandatory, it maybe more convenient to remove the Gear Train Assembly (Figure 6-15) to provide easier access. - 2. Remove the plastic latch clip (D-Roller bushing, Figure 6-42). Use needle nose pliers to twist counter clockwise and pull it out through the access opening in the Gear Train Assembly. [c)i~]~]cliv Be sure to remove the plastic latch clip as shown in Figure 6-41 before attempting to remove the D-Roller, or damage to the printer will result. Figure $-42 Removing the Pickup Feed Roller Assembly (side view) ● (continued on next page) 6-47, Removal and Replacement Bottom Assemblies 3. Lift upward on the pressure clip on the end of the Pickup Feed D-Roller and remove the D-Roller (Figure 6-43, callout 1). This provides access to one of the mounting screws. 4. Remove the (2) self-tapping screws and lift the assembly straight out (Figure 6-43, callout 2). Figure 6.43 Removing the Pickup Feed Roller Assembly (bottom view) To re-instalk Rotate the Registration Roller slightly to allow the gears to mesh before seating the assembly. CAUTION Do NOT force the assembly back into place. Be sure the gears are meshed properly before replacing screws. 6-48, Removal and Replacement Bottom Assemblies

Feeder Guide Assembly and High Voltage Shield

1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), a the Formatter Shield and PCA (Figure 6-13), the Power SwitchAssembly (-LaserJet 4P/4&lP only- Figure 6-23), and the DC Controller Assembly (Figure 6-36). 2. Remove the (2) self-tapping screws and the (1) machine screw from the Feeder Guide (Figure 6-44, callouts 1 & 2). a 3. LaserJet 4P14MP: Push the power switch grounding strap outward to provide clearance (Figure 6-44, callout 3). 4. Tilt the right edge (opposite the Toner Cartridge Lever) up first, then lift carefully up and toward the right to remove. CA LJTION LaserJet 4P/4iWP: Carefully free the Small Media Roller drive shaft before lifting upward to avoid damage (Figure 6-44, callout 4). Tore-install: LaserJet 4P/4MP: Carefully align the Small Media Roller drive shaft (Figure 6-44, callout 4) before installing the Feeder Guide. ● 6-49, Removal and Replacement Bottom Assemblies

Small Media Roller Assembly (LaserJet 4P/4MP)

1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), the Power Switch Assembly (LaserJet 4P/4MP only-Figure 6-23), the DC Controller Assembly (Figure 6-36), and the Feeder Guide Assembly (Figure 6-44). 2. Turn the Feeder Guide black side up and remove the (1) screw from the Small Media Roller bracket (Figure 6-45, callout 1). Remove the bracket and drive shaft with the attached gear. CAUTION The drive shaft is lubricated. Be careful not to contaminate the lubricant when handling. 3. Using a small, flat-blade screwdriver, push the (2) retaining tabs ~ownward to release the Roller A&embly (Figure 6-451 callout 2). Slide the assembly off the Feeder Guide. F@Jre 6-45 Removing Me Small Media Roller Assembly To re-instalk Carefully align the Small Media Roller drive shaft (Figure 6-44, callout 4) before sliding the Feeder Guide into place. 6-50, Removal and Replacement Bottom Assemblies

Static Eliminator Strip Assembly

The Static Eliminator Strip is on the under-side of the Feeder Guide Assembly. vfARN!NG! The metal teeth on the Static Eliminator Strip are very sharp and can cause injury. 1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), the Power Switch Assembly (LaserJet 4P/4MP only- Figure 6-23), the DC Controller Assembly (Figure 6-36), and the Feeder Guide Assembly (Figure 6-44). 2. Turn the Feeder Guide Assembly over, and slide the Static Eliminator Strip to the right wh;le pushing the center tab out to release (Figure 6-46, callout 1). -. ..- ‘- “- m.“,.a.F, ....-” a, . 6-51, Removal and Replacement Bottom Assemblies

Toner Cartridge Lever Assembly

The Toner Cartridge Lever Assembly is mounted on the surface of the Feeder Guide Assembly. 1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), the Power Switch Assembly (-LaserJet 4P/4MP only- Figure 6-23), the DC Controller Assembly (Figure 6-36), and the Feeder Guide Assembly (Figure 6-44), 2. Push upward on the plastic latch which holds the axis shaft in place. Slide the axis shaft out (Figure 6-47). 3. Lift the Toner Cartridge Lever Assembly out to remove. F-icJw’6e-47 Rei”mwin‘cthjeTCmw cartridge her ASsen?iiy 6-52, Removal and Replacement BCYMNTAI ssemblies

Top Door Switch (Plunger Assembly)

1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), ● the Formatter Shield and PCA (Figure 6-13), the Power SwitchAssembly (Lasenlet 4P/4MP only- Figure 6-23), the DC Controller Assembly (Figure 6-36), and the Feeder Guide Assembly (Figure 6-44). ● 2. Pry outward on the tab and slide the Top Door Switch out of the printer (Figure 6-48). 6-53, Removal and Replacement Bottom Assemblies

DC Controller/Scanner Connector Assembly

1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PC!A (Figure 6-13), and the Power Switch Assembly (LaserJet 4P/4MP only- Figure 6-23). 2. Remove the Laser/Scanner Assembly (Figure 6-21), the Gear Train Assembly (Figure 6-15), the DC Controller Assembly (Figure 6-36), and the Feeder Guide Assembly (Figure 6-44). 3. From the left side of the minter, release messure on the two 6-54, Removal and Replacement Bottom Assemblies 6-55, Removal and Replacement Bottom Assemblies

PSI Input Paper Sensor Arm

The PSI Input Paper Sensor Arm is located under the Feeder Guide Assembly and High Voltage Shield. 1. Remove the Printer Cover, the Fusing Assembly (Figure 6-27), the Formatter Shield and PCA (Figure 6-13), the Power Switch Assembly (LaserJet 4P/4MP only- Figure 6-23), the DC Controller Assembly (Figure 6-36), and the Feeder Guide Assembly (Figure 6-44). 2. LaserJet 4L only: If necessary, remove the metal High Voltage Shield by lifting it out. 3. Lift the Input Paper Sensor Arm out. Figure 6-5-i Remioving the inputPaper.%wsw Am To re-instalk Be certain the Input Paper Sensor Arm and High Voltage Shield are aligned correctly when replacing. Mis-alignment or excessive force will break the delicate sensor arm. 6-56, Troubleshooting, Troubleshooting Troubleshooting Flowchart

Troubleshooting Flowchart

● When ac power is first applied to the printer: -The exhaust fan is enabled (4L/4ML: 35 seconds; 4P/4MP:continuous). -The Main Motor rotates for about 5 seconds. -Lights illuminate for about 1 second, then o ACPoweirsapplied 4L/4ML: individually sequence front to rear, totheprinter, 4P/4MP: panel displays 05 SELF TEST, then 02 WARM UP, then 00 READY. NOTE: The fan will NOT rotate if any error condition is present. Refer to Tables 7-1 through 7.15 to correct, If no error or service message is being displayed, the Top Door is closed, and the toner cartridge is installed, yet the fan does NOT rotate when ac power is applied to the printer, verify the following: 1. Power at the receptacle is good. Yes 2 The fan is fully seated into its connector at the Scanner Assembly. 3. The Scanner is fully seated into its connector on the DC Controller PCA. 4, FusesFU101 and FU202 on the DC Controller are NOT open. If no error or service message is being displayed, the Top Door is closed, and the toner cartridge is installed, yet the Main Motor a does NOT rotate when ac power is applied to the printer, verify the following: 1. Motor is correctly mounted on chassis and seated into DC Controller connector. 2. Replace the Main Motor. a 3. Replace the DC Controller PCA. (continueodnnextpage) 7-2, Troubleshooting Troubleshooting Flowchart If the Control Panel is not functional: 1. Verify Formatter PCA is fully seated into the DC Controller PCA. 2. Replace the Formatter PCA. 3. Replace the DC Controller PCA. aPerioarnmEngiTnest, Refer to the section “image Formation Troubleshooting,” later in this chapter. [f the engine test produces a clear print image, yet a clear Self Testis not generated by the front panel self test procedure, replace the Formatter PCA. 7-3, Troubleshooting Paper Path and Components

Paper Path and Components I DC Controller PCA

Figure 7-1 Paper Path and Components Psl Input Paper Sensor Input Paper Sensor (PSI ) Positions: PS2 Paper Out Sensor A = Manual Feed Sense Position PS3 Exit Paper Sensor B = Registration Sense Position a PS4 Winding Paper Sensor C = TOP Sense Position 7-4, Troubleshooting DCController Diagram

DC Controller Diagram

TO FRONT OF PRINTER VR301 I ‘– ––––––f I PslI J301 I1–––A;P; –––IClrcultry I J202 ~ [ FUIOI IOA (12~ m ~H PS3n .J-J SW301 [(PS301) J*~~J103 000 0 Figure 7-2 DC Controller PCA Components J201 Formatter Connector J404 Drum Ground J202 Laser/Scanner Connector VR301 Leading Edge Adjustment J601 Main Motor Drive SW301 Engine Test Print Microswitch J103 Fusing Assy (Heating Element SW201 Top Door / and Thermoprotector) Toner Cartridge Microswitch J204 Fusing Assy (Thermistor THI ) PSI Input Paper Sensor J206 Pickup Solenoid SL2 PS2 Paper Out Sensor J207 Paper Feed Solenoid SL1 PS3 Exit Paper Sensor J401 Primary Charge Roller PS4 Winding Paper Sensor J402 Developer Roller FU201 DC Controller Power Supply Fuse J403 Transfer Roller FU1OI Fusing System Circuitry Fuse —, 7-5, Troubleshooting Printer Error Troubleshooting

Printer Error !Ikoubleshooting

● The printers use various means for conveying status and error messages, as follows:

LaserJet 41J4ML:

e The HP LaserJet 4L/4ML printers are the first of the HP LaserJet family that do not use a di;play panel interface. Information regarding printer status is conveyed by two methods: 1) the printer’s Control Panel lights, and 2) feedback through the hi-directional 1/0 to display on the host computer. The basic method of determining error messages uses patterns of lights on the front panel LEDs. Printer messages are categorized into two basic types: Recoverable Errors, and Service Errors. Both types are covered in the following sections. Note Before troubleshooting a Service Error, cycle the power to the printer to see if the error persists.

LaserJet 4P/4MP:

The LaserJet 4P/4MP uses an alphanumeric display panel for conveying status and error messages. In addition, as in the LaserJet 4L, feedback is directed through the printers hi-directional 1/0 to display on the host computer. ● 7-6, Troubleshooting Printer Error Troubleshooting

Priority of Errors

Each error has a priority in relation to the others. If there is more than one error condition at the same time, the highest priority error will be displayed. The priority of errors is: 1. Service Errors 2. Door Open/No Toner Cartridge 3. Paper Jam 4. Paper Out 5. Memory Error 6. Manual Feed

Recoverable Errors

Recoverable Errors are displayed on single front panel lights without pressing the front panel button. Recoverable errors do not require a service call unless the error persists after the suggested remedy has been implemented. Recoverable errors are listed in Tables 7-1 through 7-5. Table 7-1 Pa~er Out Error LaserJet LaserJet 4P/4MP I Description & Recommendations4L/4ML LEDs Display Panel PC LOAD [paper size] 1. Paper Cassette is empty or missing. ~ 2, Add paper and/or insert cassette.3. Reseat the cassette.4, Check if Paper Out flag PS2 (bottom ofprinter, adjacent to the Pickup D-Roller) is LPaper light is broken or movement is hindered. Unstickon steady. All or replace the Pickup Assembly.other lights are 5. Replace DC Controller PCA.off. 7-7, Troubleshooting Printer Error Troubleshooting Table 7-2 Paper Jam Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel += 13 PAPER JAM 1, Paper in printer. Remove paper by ~+; referring to Chapter 4, Clearing Paper Jams. 2. Rear Door Open. Close door and reset am printer. 1 UH 3. Jam removed but printer not reset. ‘aper light is Perform front panel reset. )Iinking. All 4. Transfer Roller Guide Plate not installed ]ther lights are correctly (all 3 tabs must be in position), )ff. See Chapter 6 for installation procedure. 5. Stuck or broken flags/sensors. Note where the leading edge of the paper is to determine which paper sensor maybe causing the jam. Ensure sensor flags rotate freely. Replace flags or associated assemblies if broken or if they remain stuck. 6. Paper fragment under oblique rollers (top or front). Remove rollers and clear out paper. 7. Main Motor faulty. Power up the printer and observe if the stacker rollers rotate. If not, replace the Motor. 8. Stuck or Faulty Gears in Gear Train. Replace Gear Train. 9. Toner cartridge not rotating. Refer to “Drum Rotation Functional Check later in this chapter. 10. Transfer Roller Gear missing or broken. Replace the Transfer Roller. 11. Stuck or broken solenoids. Replace solenoid or associated assembly. 12. DC Controller PCA faulty. Replace PCA. 13. Software related: for example, program in letter, but feeding legal size paper. Change the software paper size setting, or. feed the designated size. — 7-8, Troubleshooting Printer Error Troubleshooting Table 7-3 Door Open Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel $m 12 OPEN OR NO EP 1. Printer’s Top Door is open andior the ma toner cartridge is missing or not installed properly. Reinstall toner cartridge and close ~m door. D o= 2. Part of the Top Door that pushes the Error light is on plunger down is broken. Replace the Top steady. All Door, other lights are 3, Top Door Switch (Plunger Assembly) is off. broken. Replace (see Figure 7-3). 4, Toner Cartridge Lever Assembly is broken, Replace the Assembly, 5, Faulty Microswitch SW201 (Top Door Switch) on the DC Controller PCA, Replace DC Controller PCA. Top Door Microswitch (SW201 ) Metal Switch Arm - - - ..—. Figure T-3 Top Door/Toner cartridge Plunger and Lever Assembly 7-9, ,’ Troubleshooting Printer Error Troubleshooting Table 7-4 Memorv Error LaserJet LaserJet 4P/4MP Description & Recommendations lL/4ML LEDs Display Panel 20 MEM OVERFLOW 1. Too much data, or data too complex. 21 PRINT OVERRUN Turn Page Protection ON or to AUTO (can 22 ERROR be set within HP Explorer’s Remote Control Panel). 2. Add optional memory. ‘r’or light is 3. Reduce the complexity of the print job. inking, and I other lights LaserJet 4P/4MP: Press ~ to e off. resume r)rintina. Table 7-5 Manual Feed LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Dis~.lav . Panel AF FEED [paper size] 1, Insert paper into the manual feed slot. AE FEED[env. size] This will fulfill the manual feed request. 2, To avoid manual feed on this job, press the front panel button to override the manual feed request and to feed paper from Data light is the paper cassette. blinking, and 3. To avoid manual feed on future jobs, go all other lights into a software application or the HP are off, LaserJet Explorer to change the setting from Manual Feed to Paper Cassette feed. 7-1o, Troubleshooting Printer Error Troubleshooting

Service Errors ServiceErrors inhibit further operation of the printer until some

action is taken. LaserJet 4L/4ML All lights will turn on in a steady state. Pressing and holding the front panel button will reveal a pattern on the lights. (The error pattern will only be displayed as long as the front panel button is held down.) Use this pattern and the corresponding reference in Tables 7-6 through 7-15 to identify what type of service error has occurred. LaserJet 4P/4MP Service messages are displayed on the front Control Panel in the same manner as all other messages. No action is required to display further error codes. Table 7-6 Service Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel fim Not Applicable There is a service error. Press and hold E~lca l (LaserJet 4L14ML the front panel button to display the errorlight code. This code will be shown onlyQDI Only) while the button is pressed, The followingC)m tables list possible error codes. All four lights on (without NOTE: If no further error code is displayed, pressing the yet all four lights remain on continuously, front t3anel power cycle the printer. If the condition l!wiL- persists, replace the Formatter PCA. 7-11, Troubleshooting Printer Error Troubleshooting Table 7-7 Fuser Error LaserJet LaserJet 4P/4MP I Description & Recommendations4L/4ML LEDs Display Panel \m 50 SERVICE 1. Remove power to the printer for 15

END l minutes. If this doesn’t clear the error:2. Perform the Fuser Checks shown in thefg= table below.C)m 3. Check the Fuses (FU101 and FU201) on

Ready and Er- the DC Controller PCA. Replace if faulty. ror lights are on 3. Replace the DC Controller PCA. and all others are off. 1 Table 7-8 Fuser Checks SUSPECT. I CHECK I 1. Connector Contact Ensure that J103 and J204 connectors on the Fusing Assembly are seated securely into the DC Controller PCA connectors (see Figure 6-29 in Chapter 6 for locations). Reseat the Fusing Assembly, 2. Thermistor wire open. Remove the Fuser and measure the resistance between connectors J204-1 and J204-2 (see Figure 6-29 in Chapter 6 for location), Resistance should read approximately 440 K Ohms at 20 Deg C (room temperature). If the thermistor wire is open, replace the Fusing Assembly. 3. Thermal Fuse. Measure the continuity between connectors JI 03-1 and J1 03-2 on the Fuser (see Figure 6-29, Chapter 6 for location). It should be approximately 29 Ohms. If the thermal fuse is open, replace the Fusing Assembly 7-12, Troubleshooting Printer Error Troubleshooting Table 7-9 Beam Error LaserJet LaserJet 4P/4MP I Description & Recommendations4L/4ML LEDs Disp.lay . Panel ;m 51 ERROR Power-cycle the printer. If this doesn’t clear

EElm l the error:1. Reseat the Laser/Scanner Assembly intoam the Scanner/DC Cable Assembly.UD 2. Replace the Laser/Scanner Assembly.

Data and Error 3. Replace the DC Controller PCA, lights are on 4. Replace the Scanner/DC Cable and all others Assembly. are off. Table ‘7-1O Scanner Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel 52 ERROR Power-cycle the printer. If this doesn’t clear ;: the error: 1, Ensure condensation from moving the Qm printer from a cold to warm environment D UE3 hasn’t occurred, Allow the printer 6 hours to Paper and Er- acclimate to the warm room. ror lights are on 2. Reseat the Scanning Assembly. and all others 3. Replace the Laser/Scanner Assembly. are off. 4. Replace the DC Controller PCA, 5. Replace the Scanner/DC Cable Assembly, 7-13, Troubleshooting Printer Error Troubleshooting — Table 7-11 RAM/ROM Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel [XY-ZZ] ERROR An error has been found in RAM or ROM. 1. Power-cycle the printer. If this doesn’t clear the error: 2. Power off the printer, remove any additional memory, then power back on. If the message clears, replace the memory card. 3. Replace the Formatter PCA. LaserJet 4P/4MP: Use the list below to decode the [XY-ZZ] values: X - Hardware type: O = ROM 1. RAM Y- Hardware device: O. On board RAM/ROM. 1 = SIMM slot one. 2 = SIMM slot tWO. 3 = SIMM slot three. ZZ - Error Number: 00= Unsupported memory. 01 = Unrecognized memory. 02= Unsupported memory size 03= Failed RAM test. 04= Exceeded max RAM size. 05= Exceeded max ROM size. 06= Invalid SIMM speed. 07= SIMM reporting incorrect. 08= SIMM RAM parity error. 7-14, Troubleshooting Printer Error Troubleshooting Table 7-12 Engine Error ● LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel += 55 ERROR The Formatter and DC Controller are not ~m communicating. Power-cycle the printer, Ifa this doesn’t clear the message: ~= 1. Reseat the Formatter PCA into the DC D Om Controller connector, Error light is on; 2. Replace the Formatter PCA. all others are 3. Replace the DC Controller PCA. off. 4. Replace the DC Controller connector. Table 7-13 Main Motor Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel (See Tab/e 7-2, 57 ERROR The DC Controller has reported a general Paper Jam) motor failure. The Main Motor is controlled by the DC Controller PCA, and seated into connector J601. Power-cycle the printer. If this doesn’t clear the message: 1, Reseat the Main Motor into the DC Controller connector. 2, Inspect the Gear Train for debris that would block the free operation of the gears, 3. The toner cartridge may not be rotating. Refer to “Drum Rotation Functional Check later in this chapter, 4, Main Motor faulty. Power-up the printer and observe if stacker rollers rotate. If not, replace the Main Motor, 5. Replace the DC Controller PCA. 7-15, Troubleshooting Printer Error Troubleshooting Table 7-14 Fan Error ● LaserJet 4P/4MP Description & Recommendations m Dis,l,a.vPanel 58 SERVICE 1. Power-cycle the printer. 2. Check the fan to determine if it is blocked from operation. 3. Reseat the fan connector on the Laser/Scanner Assembly. Ready, Data 4, Replace the Fan. and Error lights 5. Replace the Laser/Scanner Assembly. are on and all 6. Replace the DC Controller. others are off, 7, Replace the connector between the Scanner and DC Controller. Table 7-15 Formatter Error LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel f= 61-67 SERVICE 1. Power-cycle the printer. ~m 70-71 ERROR 2. Replace the Formatter PCA. 72-79 SERVICE am D on Error light is off; the other lights display some pattern (not oth- erwise shown in this table). 7-16, Troubleshooting Printer Error Troubleshooting Table 7-16 NVRAM Error LaserJet 4ML LaserJet 4P/4MP I Description & RecommendationsLEDs Disr,).lav Panel See Table 7- 68 ERROR 68 ERROR indicates a recoverable error in ‘ 1, RAM Error) 68 SERVICE NVRAM. Press Continue to clear, then check control panel settings. One or more fields will have been reset to factory defaults during recovery. 68 SERVICE indicates NVRAM is full. 1. Perform NVRAM Reset to clear NVRAM (hold down ~ key during power-on). 2. Replace the Formatter PCA. — Table ‘7-17 Blank Display LaserJet LaserJet 4P/4MP Description & Recommendations 4L/4ML LEDs Display Panel $m [blank] If the printer’s lights remain off ~m (LaserJet 4L/4ML) or the message display am panel remains blank (LaserJet 4P/4MP), check the following: 3 Um 1. (4 L/4ML): Printer is in Intelligent Off Ml lights off mode. Press the front panel button, or open blank display). the Top Door. 2. Power is not supplied to the printer. Check power cord connections and power source. 3. Print an engine test print to determine if the print engine is functional, If the testis successful, replace the Formatter PCA. 4. Check FusesFU101 and FU201 on the DC Controller PCA. Replace if necessary. 5. Replace the DC Controller PCA. 6. Replace the connector between the DC Controller and the Formatter. 7-17, Troubleshooting Printer Error Troubleshooting

Clearable Warnings (LaserJet 4P/4MP)

A clearable warning indicates a transient condition in the printer. The printer continues on line while the message is displayed, in place of os F%JXWA. clearable warning appears each time the printer alters resolution or page protection (this causes reconfiguration of memory), or aborts a job due to an invalid or uninstalled personality, or insufficient memory. Message Displayed I Meaning WI IMAGE ASSIST The printer received a graphics print file that was too complex to print at the requested resolution. The printer automatically processed the file in the highest resolution possible with the memory installed. Add additional memory to print the file at full resolution. Check the printout for loss of data or print quality. W2 INVALID PERS The job was not printed because the requested personality, such as PostScript, was not installed. Install the language in which the files are sent, together with enough memory to support that language. vV3 JOB ABORTED The printer was forced to aborl the print job because there was not enough installed memory to support the printer language used. vV4JOB 300/OFF The job was printed at 300 dpi with page protection off. To print the 10b as requested, install additional memory, $/5 JOB 300/LTR The job was printed at 300 dpi with page protection set to letter. To print the 10bas requested, install additional memory. f16 JOB 3001A4 The job was printed at 300 dpi with page protection set to A4. To print the job as requested, install additional memory. JV7JOB 300/LGL The job was printed at 300 dpi with page protection set to legal. To print the iob as requested, install additional memory. $/8 JOB 600/OFF The job was printed at 600 dpi with page protection off. To print the iob as requested, install additional memory. h19 JOB 600/LTR The job was printed at 600 do with page protection set to letter. To print the iob as requested, install additional memory. ArOJOB 600/A4 The job was printed at 600 dpi with page protection set to A4, To print the job as requested, install additional memory. 7-18, Image Formation Troubleshooting

Image Formation Troubleshooting

● This section illustrates some image defects and their possible causes. Since there are many var[ables in the printing process, it is possible to encounter image defects that are not illustrated below. If you find a defect that is not illustrated, record the probable o cause along with the printing environmental conditions and save a copy of the defect for future reference. 7-19, Troubleshooting Image Formation Troubleshooting

Lf@ww’i’“i’4’L’’”

&h!?1/.o1, ,: /,:,.1,?,,B<,.i[ /.,1>,3,(,.<,>,2s,,(,,’,.!<,>,,,(3 BLANK PAGE FADED PRINT (See Table 7-1 8) (See Table 7-20) BLACK PAGE VERTICAL WHITE STRIPES (See Table 7-1 9) (See Table 7-21 ) 7-20, Troubleshooting [image Formation Troubleshooting I II I .,., .WI1JVERTICAL BLACK LINES REPETITIVE DEFECTS (See Table 7-22) (See Table 7-24) — Y J[ HORIZONTAL BLACK LINES STAINING (See Table 7-23) (See Table 7-25) 7-21, Troubleshooting Image Formation Troubleshooting DROPOUT BACKGROUND SCATTER (See Table 7-26) (See Table 7-28) fb..&tvi‘=iK@

I!kylal –-&x2l6 Scalable‘Wef.ce,

CHARACTER VOIDS BOTTOM PORTION BLANK (See Table 7-27) (See Table 7-29), Troubleshooting Image Formation Troubleshooting FAULTY REGISTRATION IMAGE SKEW (See Table 7-30) (See Table 7-32) — — o ● ‘-4 1 SMEARED PRINT COMPRESSED PRINT (See Table 7-31 ) (See Table 7-33) ● 7-23, Image Formation Troubleshooting — Table 7-18 Blank (White) Page POSSIBLE CAUSE RECOMMENDED ACTION OCCASIONAL BLANK PAGES: 1, Software Configuration. Make sure the application software is not sending incorrect page length requests, or extra page eject commands. 2. Network Configuration, Some sharing Check with the Network Administrator. devices on networks may generate a blank page as a separator. 3. Multiple Feeds. Theprinter maybe Remove the paper from the paper feeding two or more pages at once be- cassette and fan the edges of the paper cause the paper is difficult to separate. to separate the pages. Refer to “Media Specifications” in Chapter 2 to ensure paper meets recommendations. ALL PAGES BLANK: 1. Sealing tape left in toner cartridge. Remove the sealing tape. 2, Empty or defective toner cartridge. If unsure, weigh the cartridge: Full weight = 852 grams (30.1 OZ) Empty weight = 730 grams (25,8 OZ) Perform the “Drum Rotation Functional Check’ described later in this chapter or try a known good toner cartridge, Replace the toner cartridge if necessarv. 3. Defective or contaminated Transfer Check roller installation and contact. Roller. Without a functional Transfer Perform the “Half Self Test Functional Roller, toner cannot be pulled from the Check described later in this chapter. If photosensitive drum to the paper. there is an image on the drum, but not on paper, replace the Transfer Roller. 4, Laser/Scanner door not opening 1. Remove and re-seat the toner properly. cartridge. 2, Check the Laser/Scanner shutter door for proper operation. If defective, replace the Laser/Scanner Assemblv. (continued on next page) 7-24, Troubleshooting Image Formation Troubleshooting ALL PAGES BLANK (continued) 5. High Voltage Connector Assembly is Check the pins and springs for defective. The High Voltage Connector functionality. Clean if dirty, replace is Assembly mounts on the DC Controller defective or missing. PCA and uses spring-loaded pins to con- tact the toner cartridge. 6. DC Controller PCA is defective, The Replace the DC Controller PCA. DC Controller supplies the proper volt- age to the High Voltage contacts. Table 7-19 Black Page POSSIBLE CAUSE RECOMMENDED ACTION 1. Defective toner cartridge. Replace the toner cartridge, 2. Light is leaking into the printer. Ensure all covers are in place. 3. High Voltage Connector Assembly is Inspect and clean the contacts on the defective. The High Voltage Connector High Voltage Connector Assembly. Assembly mounts on the DC Controller Closely inspect the primary roller PCA and uses spring-loaded pins to con- contacts (see Figure 7-2). If damaged, tact the toner cartridge. replace the High Voltage Connector Assembly. 4. High voltage power supply circuit is de- Replace the DC Controller PCA. fective (not supplying the correct nega- tive voltage). 5. DC Controller PCA is defective. If the Replace the DC Controller PCA. DC Controller turns ON the laser beam continuously, the entire surface of the Photosensitive drum is neutralized caus- ing a completely black page. 7, Laser/Scanner Assembly faulty (turn- Replace the Laser/Scanner Assembly. ino laser on continuously). 8. Connector between the Laser/Scanner Replace the Scanner/DC Controller Assembly and DC Controller is defective. connector, 7-25, Troubleshooting Image Formation Troubleshooting ● Table 7-20 Faded Print ● POSSIBLE CAUSE RECOMMENDED ACTION 1. Toner supply low, Shake the cartridge gently to redistribute the toner, or replace the cartridge. 2. Print Density is set incorrectly, Print Change to a darker setting and retry Density is adjustable through software, printing. through HP Explorer’s Remote Control Panel, or through the front control panel ~LaserJet 4P/4MP). 3. EconoMode is on. EconoMode saves Turn EconoMode off through software, toner by reducing the dot density. This through HP Explorer’s Remote Control may appear to be a print quality problem Panel, or through the front control panel in some cases. (LaserJet 4P/4MP). 4. Paper does not meet specs. The mois- Try a different paper lot (see ‘(Media ture content, conductivity, or surface fin- Specifications” in Chapter 2). ish may not work correctly with the printer’s electrophotographic process. 5. Transfer Roller is defective or incor- Inspect the Transfer Roller for proper rectly installed. If the transfer roller loses installation and contact. If the Transfer conductivity, it cannot effectively pull Roller is damaged, replace it. toner from the drum to the paper. 6. Laser/Scanner door not opening 1. Remove and re-seat the toner properly. cartridge. 2, Check the Laser/Scanner shutter door for proper operation. If defective, replace the Laser/Scanner Assembly. 7. High Voltage Connector Assembly is Check the pins and springs for defective. The High Voltage Connector functionality, If dirty, clean using alcohol; Assembly mounts on the DC Controller if damaged, replace the High Voltage PCA and uses spring-loaded pins to con- Connector Assembly. tact the toner cartridge. 8. DC Controller PCA is defective. The Replace the DC Controller PCA. DC Controller supplies the proper volt- age to the High Voltage contacts. 7-26, Troubleshooting Image Formation Troubleshooting a ● T✌able 7-21 Vertical White Stripes POSSIBLE CAUSE RECOMMENDED ACTION 11. Toner cartridge is nearly empty. This Remove the toner cartridge and shake it can cause uneven toner ciistribution. gently. The cartridge will soon require ● replacement,— 2. Toner cartridge has been exposed to Store the toner cartridge in a darkened too much light. environment forseveral days. This may restore the photosensitive potential. 3. Contaminated Beam-to-Drum Mirror. Inspect themirror. Use filtered, A dirty mirror will reduce the amount of compressed air to clean. If still dirty, light that reaches the toner cartridge’s clean it carefully using lens cleaner and photosensitive drum, a lint free cloth or swab. NOTE: An excessively dusty environ- NOTE: If removing the mirror, note its ment can allow dust particles to be alignment position relative to the mark on drawn into the printer, contaminating the the printer chassis before loosening the Beam-to-Drum Mirror. screw on the right end. If the mirror needs adjustment, refer to the procedure under “Beam-to-Drum Mirror Adjustment” later in this chapter. 4, Foreign objects in beam path. Any for- Remove the toner cartridge and check eign objects will block the light from de- the laser beam printer slot for foreign veloping an image on the Photosensitive objects. Replace the toner cartridge if it drum. is damaged. Remove the Printer Cover and inspect the path from the Laser/Scanner to the mirror, looking for foreign objects in the a beam path. Replace the Laser/Scanner Assembly if the lens is scratched. 7-27, Troubleshooting Image Formation Troubleshooting Table 7-22 Vertical Black Lines ,0 POSSIBLE CAUSE RECOMMENDED ACTION 11. Toner cartridge is damaged. Inspect the toner cartridge for a scratched photosensitive drum or toner leaking through worn seals. Replace as necessary. 2. Fusing Assembly is contaminated or Inspect the Fusing Assembly for toner damaged. build-up or scratches on the fuser rollers Try cleaning with alcohol. Replace the Fusing AssemblV if damaged. 3. Static Eliminator Strip teeth are con- Remove and inspect (see Chapter 6 for taminated or defective. removal procedure). Cleansing compressed air. Replace if damaged. Table 7-23 Horizontal Black Lines POSSIBLE CAUSE RECOMMENDED ACTION 1. Toner cartridge not seated properly. Remove the cartridge and reinserl it. 2. Toner cartridge defective, Replace the cartridge. 3. Repetitive defect. If the lines are Refer to Table 7-24 (next), as well as the repeated at a consistent interval down “Repetitive Image Defect Ruler: (Figure 7-9), the page, this is a repetitive defect. 7-28, Troubleshooting image Formation Troubleshooting Table 7’-24 Repetitive Defeck When troubleshooting repetitive image defects, use the Repetitive Image Defect Ruler, supplied in Figure 7-9 to measure the distance between recurring defects. POSSIBLE CAUSE RECOMMENDED ACTION 1. Toner cartridge is damaged. The circumference of the photoconductive drum inside the toner cartridge is 75 mm (2.95 inches). If the defect repeats at this interval, the defect is associated with the drum. Inspect the drum for scratches or damage, Replace the toner cartridge. 2. Dirty Rollers. Any dirty roller in the pa- Examine and clean rollers in the paper per path may result in a repetitive print path (refer to “Cleaning Printer defect. Components” in Chapter 4). 3. Fusing Assembly is dirty or defective. The circumference of the lower fusing Pressure Roller is 47 mm (1 .85 inches). If the defect repeats at this interval, the defect is associated with the Pressure Roller, Clean the Fusing Assembly using alcohol. If the problem persists, replace the Fusinq Assemblv. 4. Gears are worn, causing slippage or Inspect the gears driving the toner umping. cartridge and the Fuser. Replace the Gear Train Assembly if necessary. 5. Paper does not meet specs. The sur- Try a different paper lot (see “Media ‘ace of the paper maybe too coarse, Specifications” in Chapter 2), ~ausing repeated marks. 7-29, Troubleshooting Image Formation Troubleshooting Table 7-25 Staining ● POSSIBLE CAUSE RECOMMENDED ACTION 1, Printing on wrong side of paper, The Check for the arrow on the paper label on the ream of paper indicates wrapper. Be sure paper is loaded with which side to print on. The different sur- the arrow pointing down in the paper face properties of some papers may cassette. cause problems if loaded wron~ side up. 2, Dirty printer. Clean the inside of the printer as described in Chapter 4. 3. Dirty Transfer Roller. This problem is Clean the Transfer Roller using a dry, characterized by staining on the back of lint-free cloth. the paper and will not occur unless the Transfer Roller is extremely dirty. 4. Toner build-up in the Fusing Assem- Remove and clean the Fusing Assembly bly. Toner build-up can physically dam- (see Chapter 6). age the Fusing Assembly. 5, Toner build-up caused by duplexing. Either avoid duplexing or clean the printer more often. 6. Leaking toner cartridge. ReDlace the toner cartridqe. 7. Paper does not meet specs. The pa- Try a different paper lot (see “Media per moisture content, conductivity, or sur- Specifications” in Chapter 2). face finish may not work correctly with the printer’s electrophotographic process. 7-30, Troubleshooting Image Formation Troubleshooting Table 7-26 Dropout POSSIBLE CAUSE RECOMMENDED ACTION 1, Single sheet of paper defective. Try reprinting the iob. 2. Paper does not meet specs. The pa- Try a different paper lot (see “Media per moisture content, conductivity, or sur- Specifications” in Chapter 2). face finish may not work correctly with the printer’s electrophotographic proc- 3. High voltage power supply defective Replace the DC Controller.&4. Transfer Roller defective. Replace the Transfer Roller. Table 7-27 Character Voids POSSIBLE CAUSE RECOMMENDED ACTION 1. Bad transparencies. Transparencies Use Hewlett-Packard approved can have this problem because they are transparencies (refer to “Media not designed for proper toner adhesion, Specifications” in Chapter 2). 2. Printing on wrong side of paper. The Check for the arrow on the paper label on the ream of paper indicates wraDDer. Be sure Da~er is loaded with the which side to print on. The different sur- arrow pointing down in the paper face mo~erties of some ~a~ers mav cassette, I cause p~obiems if loaded wrong side up. 3. Bad paper lot. The surface of the pa- Try a different paper lot (see “Media per may be too smooth or rough for Specifications” in Chapter 2). proper toner adhesion, 4. Bad Transfer Roller. If the Transfer Clean the Transfer Roller using a dry, Roller has finger oils on its surface, is lint-free cloth, DO NOT touch the dirty or is worn-out, this problem can re- transfer Roller with your fingers. Suit. If the problem persists, replace the Transfer Roller Assembly. 7-31, Troubleshooting Image Formation Troubleshooting Table 7.28 Background Scatter ,0 POSSIBLE CAUSE RECOMMENDED ACTION 1. Bad Media. The moisture content, con- Try a different media (see “Paper ductivity or surface finish may not work Specifications” in Chapter 2). correctly with the electrophotographic yrocess. 2. Inside of printer is dirty (toner may Clean inside of printer (see Chapter 4). have leaked out of the toner cartridge). Install a new toner cartridge if leaking. 3. Printing on envelope seams. Printing Move the text to an area without seams, on an envelope seam can cause a back- If not printing on seams, try a higher print ground scatter problem, density setting (see item 6, below). 4. Defective toner carlridcie. Install a new toner cartridge. 5. Dirty or worn Transfer Roller, A worn Clean the Transfer Roller using a dry, lint- Transfer Roller can cause background free cloth. DO NOT touch the Transfer due to improper bias voltages. Roller with your fingers. If the problem persists, replace the Transfer Roller Assembly. 6. Print Density set too low. If the Print Adjust the print density to a higher Density is set too low, then background setting through software, through the scatter can result, particularly with Print Quality menu of the HP Explorer envelopes and heavier papers. Remote Control Panel, or through the front control panel (LaserJet 4P/4MP). Table 7-29 Bottom Portion of Page Blank POSSIBLE CAUSE RECOMMENDED ACTION 1. Page too complex. The printer can not Set Page Protect to ON or AUTO create the image fast enough to keep ,through the HP Explorer Remote Control pace with the print engine, 2. Not enough memory. The page is too Add printer memory. As an alternative, complex for standard printer memory. ~simplify the print iob. 3. Printing on legal-size paper when soft- Review software selection. Ensure that ware is specifying letter size. (This will printing is on selected size. also cause paper jams,) 7-32, Troubleshooting knage Formation Troubleshooting -raw7-33 Faulty Registration Symptoms of faulty registration are print images which are not skewed (parallel to the paper path), but which begin printing (leading edge) either too early or too late. POSSIBLE CAUSE RECOMMENDED ACTION 1. Overloaded paper cassette. If the cas- Reload proper amount of paper sette is overloaded, the Pickup Rollers squarely in the cassette. Review paper may not pick the paper up correctly. loading with the customer. 2, Paper guide on the paper cassette ad- Verify that the paper guide is adjusted for justed too tight. If the guide is pushing the correct paper size and is locked into too tightly against the paper, it maybe position. Note that too loose a setting delayed in being pulled into the printer. may cause image skewing. 3. Paper does not meet specs, The sur- Try a different paper lot (see “Media face of the paper maybe too smooth for Specifications” in Chapter 2). the Pickup and Feed Rollers to correctly feed paper into the printer. 4. Registration adjustment is required. If the top of the page does not begin printing within the proper distance from the leading edge of the paper, then a registration adjustment is required. Refer to “Leading Edge Adjustment,” later in this chapter, 5. Worn or broken drive gears. If any Replace the defective gear, if available, gear within the drive train or paper path or the Drive Train Assembly. becomes excessively worn or dirty, er- ratic paoer movement can result, 6. Worn Pickup, Oblique, and/or Registra- Inspect all paper path rollers, looking for tion Rollers. Paper is not being picked-up ~ear, cracks, or glazing. Replace the consistently. ~orn rollers. 7-33, Troubleshooting Image Formation Troubleshooting Table 7-31 Smeared Print ,0 POSSIBLE CAUSE RECOMMENDED ACTION 1, Bad media. The moisture content, con- Try a different paper lot or other media ductivity, or surface finish of the media (see “Media Specifications” in Chapter 2). being printed may not work correctly with the electrophotographic process. 2. Dirty Fusing Rollers. Toner build-up Remove and inspect the Fusing can cause the print on a page to smear. Assembly for excessive toner build-up. Clean using alcohol. 3. The Static Eliminator Strip is dirly or is Clean or replace the Static Eliminator not grounded, allowing a static charge to Strip, Usecompressed airtoclean (see remain on the page. “Static Eliminator Strip” in Chapter 6). 4. Fusing Assembly is defective. The Replace the Fusing Assembly, print will smear if the Fusing Assembly is not heated sufficiently to bond the toner image to the paper. 5. DC Controller is defective. The DC Con- If a new Fusing Assembly does not troller regulates fusing roller temperature. resolve the problem, replace the DC Controller PCA. a 7-34, Troubleshooting Image Formation Troubleshooting Table 7-32 Imaae Skew POSSIBLE CAUSE RECOMMENDED ACTION 1. Paper is loaded incorrectly. If the pa- Remove paper from the tray and install per is not installed flush into the paper paper correctly. Position the paper guide cassette, a skewing problem will result. correctly for the paper size being used. 2. Bad Paper Lot. Paper that is manufac- Try a different paper lot (see “Media tured poorly or inconsistently, or that has Specifications” in Chapter 2). too smooth or too rough a surface tex- ture can cause an imaqe skew problem. 3. Worn Pickup, Oblique, and/or Registra- Inspect all paper path rollers, looking for tion Rollers. Paper is not being picked-up wear, cracks, or glazing. Replace the consistently. worn rollers. 4. Beam-to-Drum Mirror adjustment is Refer to ‘(Beam-to-Drum Mirror required. If the mirror has been re- adjustment,” later in this chapter to moved, or the right end mounting screw adjust the image to proper tolerances. has been loosened, the mirror needs to be readjusted. 5. Manual feed skew problems. Instruct customer to feed media against left side alignment guide, and not to reinsert once the printer “grips” the media. Table 7-33 Compressed Print POSSIBLE CAUSE RECOMMENDED ACTION 1Toner carlridge bushings are too tight. Replace the toner cartridge. This may occur on refilled toner car- tridges. 2. Broken or worn gear. Inspect and replace the worn gear or assembly. 7-35, Troubleshooting Engine Test

Engine Test

a The engine test print is used to verify that the print engine is functioning correctly. The Formatter PCA is completely bypassed during an engine test. This testis therefore very useful for isolating printer problems. The engine test prints a full page of vertical lines down the entire printable area, and is thus also o useful for checking and adjusting registration.

Engine Test Button Location

The engine test print button(SW301) is located on the side of the DC Controller PCA (see Figure 7-2). It is accessible through a hole in the Gear Train plate.

Printing an Engine Test - LaserJet 4L/4ML

On the LaserJet 4L/4ML, the engine test button is accessible without removing the covers, through the I/O Door area on the left side of the printer. To print an engine test, use a long object (such as a pencil) to press the engine test button (see Figure 7-4). (Do not use a metal object.) A single test page is printed.gure 7-4 Engine Test Button and Printout, LaserJet 4L/4ML 7-36, Troubleshooting Engine Test

Printing an Engine Test - LaserJet 4P/4MP

On the LaserJet 4P/4MP, the printer’s covers and the Formatter PCA must be removed prior to printing an Engine Test. Since the covers will be removed, the printer’s safety interlocks must be defeated to provide power for running the Engine Test. To defeat the interlocks and set-up the printer for an Engine Test: 1, Remove the printer cover, the Formatter Shield and the Formatter PCA (see Chapter 6). 2. Install the paper cassette (with paper loaded). 3. Install a toner cartridge in the ptinter. Lay a large sheet of thick paper over the toner cartridge and Laser/Scanner Assembly to block out ambient room light (this will prevent black streaks on the printed output). 4. On the to~ of the winter, use a ~iece of tape to hold down the Top Door”Plunge;(sho~ in Fi&e 7-5). - 9$$/~{l$$;~;%l%wn 1 even with chassis TOEIRail to defeat.) c A$~inbly Figure7’-5 Defealingthe Top Ek90rPh,mgw (Law!kfi 4P/4MP) 7-37, Troubleshooting Engine Test 5. On the rear of the Fusing Assembly, use a pencil or flat-blade screwdriver to press the flag mechanism for the Exit Paper Sensor (PS3) in just until it is about flush with the face of the fuser (see Figure 7-6). Note Do not push the PS3 flag in more than about 1/8 inch (3 mm). If PS3 is pressed in too far, the printer will register a power-on jam and the Engine Test will not print. If this occurs, decrease the depth of the PS3 flag, power-cycle the printer, then retry the Engine Test. 6. Plug the ac power cord into the printer. ‘7. Exert downward pressure on the the toner cartridge (through the light-blocking paper) while pressing the Engine Test button SW301 . Use a pencil or other non-metallic object to reach through the access hole in the Gear Train plate (similar to that shown in Figure 7-4). 8. If the single page Engine Test does not print, power-off the printer, check the Top Door Plunger to be sure it is held all the way down (step 4), and adjust the depth of the Exit Paper Sensor flag as described in step 5. — 7-38, Troubleshooting Half Self Test Functional Check

Half Self Test Functional Check

The electrophotographic process can be subdivided into the following stages: Cleaning (Physical and Electrostatic). ● Conditioning (Primary Charge Roller).Writing (Laser Modulation). ● Development (Formation of the Toner Image).Transfer (Charge to transfer the image to paper). The purpose of the Half Self Test Check is to determine which process is malfunctioning. Perform the test as follows: 1. Initiate a printer front panel self test. 2. Open the printer’s Top Door after the paper advances half-way through the printer (about ten seconds after the Main Motor begins rotation). The leading edge of the paper should have advanced past the toner cartridge. 3. Remove the toner cartridge. 4. Open the toner cartridge’s drum shield to view the drum’s surface. If a dark and distinct toner image is present on the drum’s surface, assume that the first three functions of the electrophotographic process are functioning (conditioning, writing and developing - see chapter 5), and troubleshoot the failure as a transfer problem. If NO image is present on the photoconductive drum, perform the checks shown on the following pages. 7-39, Troubleshooting Drum Rotation Functional Check

Drum Rotation Functional Check

The photoconductive drum, located in the toner cartridge, must rotate for the mint mocess to work. The ~hotoconductive drum receives its d&e fr;m the Main Motor g&r train. To verify whether the drum is rotating 1. Open the printer’s Top Door. Remove the toner cartridge. 3. Mark the cartridge’s drive gear with a felt-tipped marker. Note the position of the mark. 4. Install the toner cartridge, and close the Top Door. The start-up sequence should rotate the drum enough to move the mark. 5. Open the printer, and inspect the gear that was marked in step 3. Verify that the mark moved. If the mark did not move, inspect the gear train to ensure that it is meshing with the toner cartridge gears. If the printer’s drive gears appear functional, and the drum does not move, replace the toner cartridge. Note This test is especially important if refilled toner cartridges have been used. ● ● ● 7-40, Troubleshooting High-Voltage Power Supply Check

High-Voltage Power Supply Check

The High-Voltage Power Supply circuitry, on the DC Controller PCA, provides the necessary voltages for the printer’s electrophotographic processes. A method for verifjring the high-voltage system is given in the table below. Table 7-34 l-ligh-Voltage System Checks CHECKS I ACTION 1, Toner cartridge connection points. Visually inspect the three connection points on the underside, right end of the toner cartridge. If they are dirty or corroded, clean the connections. Clean using alcohol only. If damaged, replace the toner 2. High Voltage Connector Assembly, The High Voltage Connector Assembly mounts on the DC Controller PCA and uses spring-loaded pins to contact the toner cartridge (see Figure 7-2 for locations). Verify that the pins are not dirty or corroded, and that the spring-loading action is functional. If the pins are dirty, clean using alcohol only; if damaged, replace the High Voltage Connector Assembly (see I lC~apter 6 ~or procedure). - 7-41, Troubleshooting Paper Curl

Paper Curl

Paper curl is inherent to the laser printing processes, and occurs when paper is subjected to heat. Paper curl tends to relax as the paper cools while resting on a flat surface. The specification for maximum paper curl when the paper is lying flat before print is 5 mm (0.2 inches). Although paper curl cannot be totally eliminated, some steps can be taken to lessen its impact, as suggested in the following table. Table 7-35 Causes of Paper Curl POSSIBLE CAUSE RECOMMENDED ACTION 1. Paper Path Try using the face-up paper delivery slot to shorten and simplify the paper path. 2. Paper Surface The recommended printing surface of the page is usually marked on the end of a ream of paper, indicated by a small arrow and the phrase “print this side first” Load paper in the Paper Cassette with the recommended printing surface facing down Jfacing up in the manual feed slot). 3. Paper Storing and Handling Over time, paper assumes the characteristics of its storage environment (in a humid environment, paper absorbs moisture; in a dry environment, paper loses moisture). Paper with higher moisture content will tend to curl more. Evaluate the storage conditions of the paper. 4. Paper Type Ail paper is manufactured differently (different textures, moisture content, drying processes, composition, etc.). Change the type of paper being used and re-evaluate the paper curl results. 7-42, Troubleshooting Adjustment Procedures

Adjustment Procedures Leading Edge Adjustment

The distance from the leading edge of a sheet of paper to the beginning of the printable area can be adjusted using VR301 located on the DC Controller PCA. Leading edge is set at the factory for new units and only needs adjustment when the DC Controller is replaced. VR301 can be accessed without removing any printer assemblies (other than the paper cassette). 1. Run a printer engine test (see “Engine Test” earlier in this chapter). Measure the leading edge distance (see Figure 7-7). If the distance is 1.5 to 2.5 mm, no adjustment is necessary. 2. If adjustment is needed, remove the paper cassette from the printer by sliding it all the way out. 3. Locate the access hole for VR301 (see Figure 7-7). 4. Turn VR301 clockwise to decrease the leading edge distance, or counter-clockwise to increase (see Figure 7-7). 5. Replace the paper cassette and run another test to compare. 6. Repeat 1 through 5 until the leading edge is within tolerance. Leading edge of paper ~ t-2m. * {+/0-.5mm+)

Q

Figure 7-7 Leading Edge Adjustment — ——————— 7-43, Troubleshooting Adjustment Procedures

Beam-to-Drum Mirror Adjustment

The mounting for the Beam-to-Drum mirror has an adjustment on the right end to correct for potential image skew problems. The mirror is adjusted at the factory for new units, but can lose its -setting if the mirror is removed for any reason, or if the adjustment screw has been loosened. To adjust the Beam-to-Drum Mirror: 1. Run a test print (an “Engine Test,” described earlier in this chapter, or another self test print, described in Chapter 3). 2. Use a pencil or pen to draw a horizontal line across the top of each vertical line on the test print image (see Figure 7-7). 3. Place the edge of a tool with an exact 90 degree corner (such as a drafting triangle) along the leftmost vertical line of the test print image, and draw a second horizontal line across the top of the page. 4. Measure the error between the lines drawn in step 2 and step 3 (see Figure 7-8). If the distance is greater than 1.5 mm, then adjustment is needed. 5. On the right end of the mirror assembly, note the current adjustment setting (if necessary, make a mark on the printer body and/or adjustment scale), and loosen the adjustment screw. 6. Shift the mirror toward the front of the printer to move the image up on the right, or toward the back of the printer to move the image upon the left. ‘7. Run another test print, repeating the above steps until the image skew is within tolerance. 7-44, Troubleshooting Adjustment Procedures Line drawn in Line drawn in About 1cm Measure here Max. = 1.5mm Adjustment direction m Image t left up Beam-to-Drum Mirror Image 4 right up lgure 7-8 Beam-to-Drum Mirror Adjustment 7-45, Troubleshooting Troubleshooting TooIs

Troubleshooting Tools Repetitive Image Defect Ruler

First occurence of print defect Developing Cylinder 38 mm (1.5 in) Primary Charging Roller 38 mm (1.5 in) Face Down Delivery (Upper) Roller 38 mm (1.5 in) Transfer Roller 44 mm (1 .75 in) Fusing Pressure Roller 47 mm (1 .85 in) Upper Fusing Assembly Film 75 mm (2.95 in) Toner Cartridge Photosensitive Drum 75 mm (2.95 in) Registration Roller 119 mm (4,7 in) Figure 7-9 Repetitive Image Defect Ruler 7-46, Troubleshooting Main Wiring Diagram

Main Wiring Diagram FRONT

1/0 CONTROLPANEL

I

Figure 7-10 Main Wiring Diagram (generalized) — 7-47, Troubleshooting Main Wiring Diagram 7-48, Parts and Diagrams How to Use the Part Lists and Diagrams

How to Use the Part Lists and Diagrams

● The figures in this chapter illustrate the major subassemblies in the printer and their component parts. A table (material list) follows each exploded assembly diagram. Each table lists the reference designator (item number) for each part, the associated part number for the item, the quantity, and a description of the ● part. While looking for a part number, pay careful attention to the voltage listed in the description column to ensure that the part number selected is for the correct model of printer.

Ordering Parts

All standard part numbers listed are stocked and may be ordered from HP’s Parts Direct Ordering, or Parts Center Europe (PCE). Hewlett-Packard Co. Support Materials Organization 8050 Foothills Blvd. Roseville, CA 95678 Parts Direct Ordering: 1-800-227-8164 (U.S. Only) Hewlett-Packard Co. Parts Center, Europe Wolf-Hirth Strasse 33 D-7030 Boeblingen, Germany (49 7031) 14-2253 Contact your local HP Parts Coordinator for other local phone numbers. 8-2, Parts and Diagrams How to L& tlhe Part Lists and Diagrams

Ordering Consumables

Consumables and accessories such as those listed on page 8-5, and in Table 4-1, Chapter 4, may be ordered direct from Hewlett-Packard. The phone numbers are: U.S: 1-800-538-8787 Canada: 1-800-387-3154 (Toronto) 416-671-8383 United Kingdom: 0734-441212 Germany: 0130-3322 !onta,ct your local HP Parts Coordinator for other local phone numbers. Note Parts that have no reference designator or part number are not field replaceable parts and cannot be ordered through SMO. 8-3, Parts and Diagrams Common Hardware

Common Hardware

Table 8-1 Common Fasteners Used in the Printer DRAWING DESCRIPTION SIZE NOTES PART NO. Phillips pan-head M3X6 E-20 in drawings XBI-2300-607CN machine screw. Phillips M3X12 Formatter PCA 0515-2419 washer-head machine screw. M3X8 Formatter PCA 0515-2251 Phillips machine M3X1O Fuser Assembly XA9-0654-OOOCN screw with captive star washer. M3X6 Feeder Gde Ground XA9-0653-OOOCN M3X6 Gear Train Ground XB2-7300-606CN M3X8 Fuser Ent Guide XB2-8300-809CN Self-tapping M4X1O G-32 in drawings XB4-7401 -O07CN Phillips screw. M4X12 Laser/Scanner XB4-7401 -209CN M3X8 G-1 7 in drawings XB4-7300-809CN 6mm 8mm 10mm 12mm M3 M4

I-II-II-II-I(O)

8-4, Parts and Diagrams Accessories and Supplies

Accessories and Supplies

The following items are available through your local authorized HP dealer. To find a dealer near you (or if your dealer is temporarily out of stock), call the HP Customer Information Center (800) 752-0900. Note Refer to “Ordering Related Documentation” in Chapter 1 for documentation part numbers. 92274A HP Toner Cartridge C2024A 1 Mb memory upgrade, LaserJet 4L only (New) C2024-69001 1 Mb memory upgrade, LaserJet 4L only (Exchange) C31 30A* 1 Mb Memory SIMMS (LaserJet 4P/4MP only) C3131A* 2Mb Memory SIMMS (LaserJet 4P/4MP only) C31 32A* 4Mb Memory SIMMS (LaserJet 4P/4MP only) C31 33A* 8Mb Memory SIMMS (LaserJet 4P/4MP only) 2049-67901” Adobe PostScript Level 2 SIMM (LaserJet 4P only) R75-001 O-OOOCN Universal Pa~er Cassette (LaserJet 4U4ML onlv) R75-201O-OOOCN I Universal Paper Cassette (LaserJet 4P/4MP only) I 24542D Parallel cable, 2 meter (Bi-tronics compatible) C2932A Serial Cable 9-9 pin M/F (LaserJet 4P/4MP only) C2933A Serial Cable 9-25 Din M/F (LaserJet 4P/4MP onlv) 8120-6177 I Right angle 11 Ov power cord (4L/4ML only) ,

I

Velcro Adhesive Cleaning Brush Holder I *C206XA SIMMS (36 bit) are also supported, however, C303XA SIMMS (32 bit) are recommended. **This PostScript SIMM is not compatible with any other printers (4P only). 8-5, Parts and Diagrams Accessories and Supplies (This page intentionally blank.) 8-6, Parts and Diagrams Accessories and Supplies Pickup Assembly (See Figure 8-1 1) PLper Cassette (See Figure 8-9 & 8-1 O) ● QQ —Formatter Assembly(See Figure 8-4)a Figure 8-? Assembly Locations (Laserdet 4L shown) ● 8-7, Parts and Diagrams Accessories and Supplies \ ? + 102II1$ 13 —9 - : —14 12— 0‘ 7 V06 Figure 8-2 Covers and Doors (LaserJet 4L/4ML only) 8-8, Parts and Diagrams Accessories and Supplies ●✌Table 8-2 Covers and Doors (LaserJet 4L/4ML only) REF PART NO, QTY I DESCRIPTION RG5-0685-OOOCN 1 lCover Assembly* a 1 RBI -2977-OOOCN 1 Door, 1/02 RB1 -2978-OOOCN 1 Door, Power 3 RBI -3131 -OOOCN 2 Shaft, ToP Door Hinge 4 RBI -3132-OOOCN 1 Button, Lock 5 RB1 -3133-OOOCN 1 Guide, Lock Button 6 RBI -3134-OOOCN 1 Spring, Left Torsion 7 RBI -3135-OOOCN 1 Spring, Right Torsion 8 RF5-0597-OOOCN 1 Cover, Main 8A RBI -3128-OOOCN 1 Front Panel Button 8B RB1 -2976-OOOCN 1 Light Pipe 8C XD2-2300-402CN 3 Washer, SE Ring 9 RB1 -3130-OOOCN 2 CRG Pressure Piece 10 RG5-0691-OOOCN 1 Door, Back Assembly 10B RBI-3138-OOOCN 1 Spring, Torsion 11 RS5-2228-OOOCN 1 Spring, ToP Door Latch 12 RBI -2979-OOOCN 1 Door, Memory 13 RS5-2227-OOOCN 2 Spring, Top Door Compression 14 XA9-0634-OOOCN 2 Screw, Top Door 15 RBI -3129-OOOCN 1 Door, Top a 16 C2003-00005 1 Nameplate, LaserJet 4L 16 C2015-00001I1INameplate, LaserJet 4ML 1V06 XD2-1 100-242CN ~ 2 I E-Clip●*Cover assembly does not include items 1, 2 and 12. 8-9, Parts and Diagrams Accessories and Supplies Figure 8-3 Covers and Doors (LaserJet 4P/4MP only) 8-10, Parts and Diagrams kcx?sSOi’ki and ~U~@5S Table 8-3 Covers and Doors (Laser.-let 4P/4MP only) REF PART NO. QTY DESCRIPTION ~ 1 Cover Assemblv 1 RB1-3352-OOOCN 1 Cover, Font 1A C2040-40002 1 Font Door Plus, LaserJet 4MP 2 RB1 -3353-OOOCN 1 Hinae, Font Cover 3 RB1 -3131 -OOOCN 2 Shaft, Top Door Hinae 4 RBI -3356-OOOCN 1 Button, Lock 5 RB1 -3357-OOOCN 1 Guide, Lock Button 6 RB1 -3798-OOOCN 1 Smina, Left Torsion 7 RB1 -3799-OOOCN 1 %rina. Riaht Torsion 8 ~ 1 Cover, Main 9 RB1-3130-OOOCN 2 CRG Pressure Piece 10 RG5-0691-OOOCN 1 Door, Back Assemblv 1oh ~ 1 .%rincl, Torsion 11 RS5-2228-OOOCN 1 .%rina, Too Door Latch 12 RB1-3417-OOOCN 1 Plate, Groundina 13 RS5-2227-OOOCN 2 %rina, TotI Door Compression 14 XA9-0634-OOOCN ~ Screw, TotI Door 15 RB1-3332-OOOCN 1 Door, TOD 16 RG5-0812-OOOCN 1 Control Panel Assembly 16A ~ 1 ~ 16B ~ 1 Bezel Assemblv 16C RG5-0816-OOOCN 1 Control Panel PCA 16D C2005-00006 1 Nametiate, LaserJet 4P 16D C2040-00001 1 Namedate, LaserJet 4MP 16F ~ Kevboard Overlav (Localized) 17 ~ 1 Sixina, Font Door Torsion 18 RG5-0813-OOOCN 1 SIMM Cover Assembly 19 RG5-0815-OOOCN 1 ~Disr)l v Cable 20 ~ 1 l/O Cover Plate, LaserJet 4P 20 ~ 1 1/0 Cover Plate, LaserJet 4MP V06 XD2-1 100-242CN 2 E-Clip 8-11, Parts and Diagrams Accessories and Supplies -E20

B

-— G32 11IIG32—4 See Figure 8-7

Figure 8-4 Internal Components 1

8-12, Parts and Diagrams Accessories and Supplies Table 8-4 Internal Components 1 REF PART NO. QTY DESCRIPTION i RG5-0703-OOOCN i Fan Assembly RG5-0669-OOOCN 1 Front Oblique Roller Assembly 3 XA9-0654-OOOCN ** Screw, M3X1O51Formatter PCA: C2004-67901 LaserJet 4L (New) C2004-69001 LaserJet 4L (Exchange) C201 6-67901 LaserJet 4ML (New)* C201 6-69001 LaserJet 4ML (Exchange)* C2006-67901 LaserJet 4P (New)* C2006-69001 LaserJet 4P (Exchange)* C2041-67901 LaserJet 4MP (New)* C2041 -69001 LaserJet 4MP (Exchange)* 6 1 DC Controller Connector 1252-5278 LaserJet 4U4ML 1252-5460 LaserJet 4P/4MP71RFI Shield: C2003-00032 LaserJet 4L C2015-00002 LaserJet 4M~ C2015-00003 LaserJet 4ML, Mini DIN* C2005-00013 LaserJet 4P/4MF R C2003-40001 1 Switch Acutuator (LaserJet 4UML) 9 ** Screw, washer-head 0515-2419 long (12 mm) 0515-2251 shorl (8 mm)* 10 RG5-0805-OOOCN 1 Power Switch (LaserJet 4P/4MP) 11 C2005-00004 1 ‘ont Guide (LaserJet 4P/4MP) 12 RBI-3405-OOOCN 1 2rounding Plate (LaserJet 4P/4MP 13 RBI-3404-OOOCN 1 Srounding Plate (LaserJet 4P/4MP *Part shown in Figure 8-4 is for other printer model; actual part looks different. **Quantity varies- dependent on prin;er model. “ 8-13, Parts and Diagrams Accessories and Supplies J?,0 8A 8B ● I —G32 —4

P

G32 /“’” Figure 8-5 Internal Components 2 8-14 ...,-”-.,1, Parts and Diagrams Accessories and Supplies Table $3-5 ink?mal Ccxrlpm?mts 2 ● l== PART NO, QTY DESCRIPTION II RF5-0596-OOOCN 1 Roller, Transfer Assembly * 1 Beam-to-Drum Mirror Assembly: RG5-0667-OOOCN LaserJet 4L/4ML RG5-0802-OOOCN LaserJet 4P/4MP 3 RG5-0674-OOOCN 1 Mount, Transfer Assembly, Left 4 RG5-0675-OOOCN 1 Mount, Transfer Assembly, Right 5 RG5-0682-OOOCN 4 Roller, Lower Output Assembly E6 RG5-0683-OOOCN 1 Roller, Upper Output Assembly7 RG5-0694-OOOCN 1 Switch, Plunger Assembly8 RG5-0702-OOOCN 1 Transfer Guide Assembly8A RBI-3073-OOOCN 2 Bushing8B RF5-0585-OOOCN 1 Transfer Guide9 RG5-0764-OOOCN 1 Motor, Main Assembly10 RG5-0766-OOOCN 1 Scanner Connector Assembly11 XA9-0495-OOOCN 1 Screw, Main Motor * Includes d~ Te gear. 8-15, Parts and Diagrams Accessories and Supplies /4 \ IIIG32—-_& Figure 8-6 Internal Components 3 8-16, Parts and Diagrams Accessories and Supplies ● T✌able 8-6 Internal Components 3 REF PART NO. QTY DESCRIPTION 1 RB1 -2971 -OOOCN 1 lBushinu, D-rollera2RB1 -3681 -OOOCN 1 Cap, Laser Shutter3 1 Plate, Fuser Ground: RB1 -2984-OOOCN LaserJet 4U4ML RBI -3403-OOOCN LaserJet 4P/4MP 4 RB1 -2987-OOOCN 1 Shield, Hiuh Voltaae 5 RG5-0805-OOOCN 1 Plate, Gear Plate Ground 5A RBI -3001 -OOOCN 4 Foot, Chassis 5B RBI -3002-OOOCN 1 Plunqer Lock, Door 5C RB1-3003-OOOCN 1 Sprinq, Scanner Leaf 5D RB1-3004-OOOCN 1 Plate, CRG 5E RS5-2232-OOOCN 1 .’%rincr, Comr)ression 6 RF5-0601-OOOCN Arm, Irmut Pa~er Sensor 7 RG5-0670-OOOCN 1 TOII Oblique Roller Assemblv81Guide, Feeder Assembly: RG5-0671-OOOCN LaserJet 4U4ML RG5-0793-OOOCN LaserJet 4P/4MP 8B RF5-0584-OOOCN 1 Static Eliminator Assemblv 8F RG5-0672-OOOCN 1 Switch, Cam Assemblv 8Q RG5-0794-OOOCN 1 Roller ASSV, Small Media (4P/4MP) 8P RBI -3365-OOOCN 1 Shaft Holder (LaserJet 4P/4MP) 8Z RS5-0364-OOOCN, 1 Drive Gear (LaserJet 4P/4MP) ● 9 1 Laser/Scanner Assembly: RG5-0662-OOOCN LaserJet 4U4ML (New) C2003-69005 LaserJet 4U4ML (Exchange) RG5-0800-OOOCN LaserJet 4P/4MP (New) ● C2005-69005 LaserJet 4P/4MP (Exchanqe)10 XA9-0653-OOOCN 1 Screw, M3X6 11 XB4-7401 -209CN 3 Screw, Scanner 12 RB1-3392-OOOCN1IDust Cover, Foam Rubber ● ’ 8-17, Parts and Diagrams Accessories and Supplies l— l-’ E20 –~ Figure 8-7 DC Controller Assembly, Parts and Diagrams Accessories and Supplies o Table 8-7 DC Controller Assembly l== PART NO. IQTYI DESCRIPTION

I-P RG5-0700-OOOCN 1 DC Controller Case Assembly

● lB RB1-3151 -OOOCN 1 Spring, Cassette SidekIc RBI-3152-OOOCN 1 Plate, Solenoid GroundlF RB1-3164-OOOCN 1 Plate, Ground RG5-0701 -OOOCN 1 High Voltage Connector Assembly31DC Controller PCA, 100-12OV: RG5-0753-OOOCN LaserJet 4U4ML (New) C2003-69003 LaserJet 4U4ML (Exchange) RG5-0822-OOOCN LaserJet 4P/4MP (New) C2005-69003 LaserJet 4P/4MP (Exchanqe) 3 1 DC Controller PCA, 220-240V: RG5-0767-OOOCN LaserJet 4U4ML (New) kC2003-69004 LaserJet 4U4ML (Exchange)RG5-0823-OOOCN LaserJet 4P/4MP (New)C2005-69004 LaserJet 4P/4MP (Exchange)4 RH7-5092-OOOCN 1 Pick-up Solenoid (SL2)5 WD1 -0288-OOOCN 1 Fuse FU1 01, 100-12OV5 VD7-0643-151 CN 1 Fuse FUI 01, 220-240V6 VD7-0522-501 CN 1 Fuse FU201, 100-120V ONLY 8-19, Parts and Diagrams Accessories and Supplies Figure 8-8 Gear Train Plate Assembly Table 8-8 Gear Train Plate Assembly REF PART NO. QTY DESCRIPTION 1 Gear Train Plate Assembly: RG5-0684-OOOCN LaserJet 4U4ML RG5-0791 -OOOCN LaserJet 4P/4MP12Spring, Leaf ● RB1 -3125-OOOCN LaserJet 4U4ML RB1-3402-OOOCN LaserJet 4P/4MP 2 XB2-7300-606CN 2 Screw, wlstar washer (M3X6) ● 8-20, Parts and Diagrams Accessories and Supplies Figure 8-9 Paper Cassette (LaserJet 4LJ4ML) Table 8-9 Paper Cassette (LaserJet 4L/4ML) REF PART NO. QTY DESCRIPTION R75-OO1O-OOOCN 1 Universal Paper Cassette 3 RB1 -3142-OOOCN 1 Guide, Forms Size 4 RB1 -3143-OOOCN 1 Claw, Separation 8 RS5-2229-OOOCN i Spring, Compression Small 9 RS5-2230-OOOCN 1 Spring, Compression Large, Parts and Diagrams Accessories and Supplies Figure 8-10 Paper Cassette (LaserJet 4P/4MP) Table 8-10 Paper Cassette (LaserJet 4P/4MP) I REF ! PART NO. I QTY I DESCRIPTION I R75-201O-OOOCN 1 Universal Pa~er Cassette 3 RB1 -3338-OOOCN 1 ~Pla e. End 4 RBI -3143-OOOCN 1 Claw, Se~aration 9 RS5-2254-OOOCN 1 %rina, Comr)ression 10 RB1 -3339-OOOCN 1 Lever ~ 12 RB1- 341-OOOCN 1 Trav, Leaal 14 I RF5-0673-OOOCNI1IPlate, Side ‘o 8-22, Parts and Diagrams Accessories and Supplies Figure 8-11 Pickup Assembly Table 8-11 Pickup Assembly REF PART NO. QTY DESCRIPTION 1 Pickup Assembly: RG5-0668-OOOCN LaserJet 4L/4ML RG5-0796-OOOCN LaserJet 4P/4MP41Pickup Feed D-Roller: RBI-3029-OOOCN LaserJet 4U4ML RB1-3368-OOOCN LaserJet 4P/4MP 8-23, Parts and Diagrams Accessories and Supplies Figure 8-12 Fuser Assembly —, Parts and Diagrams Accessories and Supplies Table 8-12 Fuser Assembly I REF I PART NO. I QTY DESCRIPTION 1 Fuser Assembly, 100-12OV: RG5-0676-OOOCN New C2003-69001 Exchange 1 Fuser Assembly, 220-240V: RG5-0677-OOOCN New C2003-69002 Exchange 1 RB1 -2981 -OOOCN 1 Tab, Fuser Release 9 RG5-0690-OOOCN 1 Suide, Fuser Entrance 12 RBI -3097-OOOCN 1 Flag, Exit Sensor 14 RB1 -3100-OOOCN 1 Roller, Fuser Pressure 15 RBI -3103-OOOCN 1 Roller, Fuser Delivery 18 RB1 -3109-OOOCN 1 Roller, Fuser Conductive Rubber 20 1 Fuser Film Assembly RG5-0678-OOOCN 100-120V RG5-0679-OOOCN 220-240V 27 RS5-2224-OOOCN 2 Spring, Fuser Hook 29 XB2-8300-809CN 2 Screw, w/star washer (M3X8) 30 RG5-0681-OOOCN 1 Fuser Delivery Assembly 30B RB1 -3107-OOOCN 2 Roller, Delivery 30C RB1 -3108-OOOCN 2 Spring, Delivery 8-25, Parts and Diagrams Accessories and Supplies Figure 8-13 Keyboard Overlay (LaserJet 4P/4MP) Table 8-13 Keyboard Overlays. (LaserJet 4P/4MP) REF PART NO. QTY DESCRIPTION11Keyboard Overlay: C2005-40002 Euro-English C2005-40003 Turkish C2005-40004 Portuguese C2005-40005 German C2005-40006 Spanish C2005-40007 French C2005-40008 Italian C2005-40009 Dutch C2005-4001 O Norwegian C2005-40011 Polish C2005-40012 Swedish C2005-40013 Finnish C2005-40014 Danish C2005-40017 Chinese C2005-40018 Taiwanese 8-26, AppendixA Parts Index, Parts Index Alphabetical Parts Index

Alphabetical Parts Index

DESCRIPTION I PART NUMBER I FIG Arm, Input Paper Sensor RF5-0601 -OOOCN 8-6 Beam-to-Drum Mirror Assembly, LJ 4U4ML RG5-0667-OOOCN 8-5 Beam-to-Drum Mirror Assembly, LJ 4P/4MP RG5-0802-OOOCN 8-5 Bezel Assembly, LJ 4P/4MP RF5-0682-OOOCN 8-3 Bushing RB1-3073-OOOCN 8-5 Bushing, D-roller RB1 -2971 -OOOCN 8-6 Button, Lock, LJ 4U4ML RBI -3132-OOOCN 8-2 Button, Lock, LJ 4P/4MP RB1 -3356-OOOCN 8-3 Cap, Laser Shutter RBI -3681 -OOOCN 8-6 Claw, Separation RBI -3143-OOOCN 8-10 Claw, Separation RBI -3143-OOOCN 8-9 Control Panel Assembly, LJ 4P/4MP RG5-0812-OOOCN 8-3 Control Panel PCA, LJ 4P/4MP RG5-0816-OOOCN 8-3 Cover Assembly, LJ 4P/4MP RG5-081 O-OOOCN 8-3 Cover Assembly, LJ 4U4ML RG5-0685-OOOCN 8-2 Cover, Font, LJ 4P/4MP RB1-3352-OOOCN 8-3 Cover, Main, LJ 4U4ML RF5-0597-OOOCN 8-2 Cover, Main, LJ 4P/4MP RF5-0681-OOOCN 8-3 CRG Pressure Piece, LJ 4U4ML RB1 -3130-OOOCN 8-2 CRG Pressure Piece, LJ 4P/4MP RBI -3130-OOOCN 8-3 DC Controller Case Assembly RG5-0700-OOOCN 8-7 DC Controller Connector, LJ 4U4ML 1252-5278 8-4 DC Controller Connector, LJ 4P/4MP 1252-5460 8-4 DC Controller PCA, 100-1 20V, LJ 4U4ML (Exchange) C2003-69003 8-7 DC Controller PCA, 100-1 20V, LJ 4U4ML (New) RG5-0753-OOOCN 8-7 DC Controller PCA, 100-120V, LJ 4P/4MP (Exchange) C2005-69003 8-7 i DC Controller PCA, 100-120V, LJ 4P/4MP (New) RG5-0822-OOOCN 8-7 Parts Index-2, Parts Index Alphabetical Parts Index DESCRIPTION I PART NUMBER I FIG I DC Controller PCA, 220-240V, LJ 4L/4ML (Exchange) C2003-69004 8-7 DC Controller PCA, 220-240V, LJ 4L/4ML (New) RG5-0767-OOOCN 8-7 DC Controller PCA, 220-240V, LJ 4P/4MP (Exchange) C2005-69004 8-7 DC Controller PCA, 220-240V, LJ 4P/4MP (New) RG5-0823-OOOCN 8-7 Display Cable, LJ 4P/4MP RG5-0815-OOOCN 8-3 Door, Back Assembly, LJ 4L/4ML RG5-0691 -OOOCN 8-2 Door, Back Assembly, LJ 4P/4MP RG5-0691 -OOOCN 8-3 Door, I/O, LJ 4L/4ML RB1 -2977-OOOCN 8-2 Door, Memory, LJ 4U4ML RBI -2979-OOOCN 8-2 Door, Power, LJ 4U4ML RBI -2978-OOOCN 8-2 Door, Top, LJ 4L/4ML RB1 -3129-OOOCN 8-2 Door, Top, LJ 4P/4MP RBI -3332-OOOCN 8-3 Drive Gear, LJ 4P/4MP RS5-0364-OOOCN 8-6 Dust Cover, Foam Rubber RB1 -3392-OOOCN 8-6 E-Clip, LJ 4L/4ML XD2-1 100-242CN 8-2 E-Clip, LJ 4P/4MP XD2-I 100-242CN 8-3 Fan Assembly RG5-0703-OOOCN 8-4 Flaq, Exit Sensor RBI-3097-OOOCN 8-12 Font Door Plug, LJ 4MP only C2040-40002 8-3 Font Guidej LJ 4P/4MP C2005-00004 8-4 Foot, Chassis RB1 -3001 -OOOCN 8-6 Formatter PCA, LJ 4L (Exchange) C2004-69001 I 8-4 Formatter PCA, LJ 4L (New) C2004-67901 8-4 Formatter PCA, LJ 4ML (Exchange) C2016-69001 8-4 Formatter PCA, LJ 4ML (New) C2016-67901 8-4 Formatter PCA, LJ 4MP (Exchange) C2041-69001 8-4 Formatter PCA, LJ 4MP (New) C2041 -67901 8-4 Formatter PCA, LJ 4P (Exchange) C2006-69001 8-4 Formatter PCA, LJ 4P (New) C2006-67901 8-4 Parts Index-3, Parts Index Alphabetical Parts Index DESCRIPTION I PART NUMBER I FIG Front Oblique Roller Assembly RG5-0669-OOOCN &4 Front Panel Button, LJ 4U4ML RBI -3128-OOOCN 8-2 Fuse FUIO1, 100-120V WD1-0288-OOOCN 8-7 Fuse FUI 01, 220-240V VD7-0643-I 51 CN 8-7 Fuse FU201, 100-120V ONLY VD7-0522-501CN 8-7 Fuser Assembly, 100-120V (Exchange) C2003-69001 8-12 Fuser Assembly, 100-120V (New) RG5-0676-OOOCN 8-12 Fuser Assembly, 220-240V (Exchange) C2003-69002 8-12 Fuser Assembly, 220-240V (New) RG5-0677-OOOCN 8-12 Fuser Delivery Assembly RG5-0681-OOOCN 8-12 Fuser Film Assy, 100/1 20V RG5-0678-OOOCN 8-12 Fuser Film Assy, 220/240V RG5-0679-OOOCN 8-12 Gear Train Plate Assembly, LJ 4U4ML RG5-0684-OOOCN 8-8 Gear Train Plate Assembly, LJ 4P/4MP RG5-0791 -OOOCN 8-8 Grounding Plate, LJ 4P/4MP RBI-3404-OOOCN 8-4 Grounding Plate, LJ 4P/4MP RB1-3405-OOOCN 8-4 Guide, Feeder Assembly, LJ 4L/4ML RG5-0671 -OOOCN 8-6 Guide, Feeder Assembly, LJ 4P/4MP RG5-0793-OOOCN 8-6 Guide, Forms Size RBI -3142-OOOCN 8-9 Guide, Fuser Entrance RG5-0690-OOOCN 8-12 Guide, Lock Button, LJ 4L/4ML RBI -3133-OOOCN 8-2 Guide, Lock Button, LJ 4P/4MP RB1 -3357-OOOCN 8-3 High Voltage Connector Assembly RG5-0701-OOOCN 8-7 Hinge, Font Cover, LJ 4P/4MP RBI -3353-OOOCN 8-3 1/0 Cover Plate, LJ 4MP only C2040-40001 8-3 1/0 Cover Plate, LJ 4P C2005-40001 8-3 Keyboard Overlay, Chinese C2005-40017 8-13 Keyboard Overlay, Danish C2005-40014 8-13 Parts Index-4, Parts Index Alphabetical Parts Index DESCRIPTION I PART NUMBER I FIG Kevboard Overlay, Dutch C2005-40009 8-13 Keyboard Overlay, Euro-English C2005-40002 8-13 IKeyboard Overlay, Finnish C2005-40013 8-13 ‘Keyboard Overlay, French C2005-40007 8-13 Keyboard Overlay, German C2005-40005 8-13 Keyboard Overlay, Italian C2005-40008 8-13 Keyboard Overlay, Norwegian C2005-4001 O 8-13 Kevboard Overlay, Polish C2005-40011 8-13 Keyboard Overlay, Portuguese C2005-40004 8-13 Keyboard Overlay, Spanish C2005-40006 8-13 Keyboard Overlay, Swedish C2005-40012 8-13 Keyboard Overlay, Taiwanese C2005-40018 8-13 Keyboard Overlay, Turkish C2005-40003 8-13 Laser/Scanner Assembly, LJ 4U4ML (Exchange) C2003-69005 8-6 Laser/Scanner Assembly, LJ 4L/4ML (New) RG5-0662-OOOCN 8-6 Laser/Scanner Assembly, LJ 4P/4MP (Exchange) C2005-69005 8-6 Laser/Scanner Assembly, LJ 4P/4MP (New) RG5-0800-OOOCN 8-6 Lever RBI -3339-OOOCN 8-10 Light Pipe, LJ 4L/4ML RB1-2976-OOOCN 8-2 M3x6 Solenoid Screw XBI -2300-607CN 8-7 M4x1 O Screw XB4-740,t -O07CN 8-1 Motor, Main Assembly RG5-0764-OOOCN 8-5 Mount, Transfer Assembly, Left RG5-0674-OOOCN 8-5 Mount, Transfer Assembly, Rioht RG5-0675-OOOCN 8-5 Nameplate, LJ 4L, LJ 4L/4ML C2003-00005 8-2 Nameplate, LJ 4ML, LJ 4L/4ML C2015-00001 8-2 Parts Index-5, Parts Index Alphabetical Parts Index

I DESCRIPTION I PART NUMBER I FIG I

Nameplate, LJ 4MP C2040-00001 8-3 ● Nameplate, LJ 4P C2005-00001 8-3 Paper Feed Solenoid (SL1 ) RH7-5092-OOOCN I 8-7 Pickup Assembly, LJ4L/4ML RG5-0668-OOOCN 8-11 Pickup Assembly, LJ4P/4MP RG5-0796-OOOCN 8-11 * Pickup Feed D-Roller, LJ4U4ML RBI -3029-OOOCN 8-11 Pickup Feed D-Roller, LJ4P/4MP RB1 -3368-OOOCN 8-11 Plate, CRG RBI -3004-OOOCN 8-6 Plate, End RBI -3338-OOOCN 8-10 Plate, Fuser Ground, LJ 4L/4ML RB1 -2984-OOOCN 8-6 Plate, Fuser Ground, LJ 4P/4MP RB1 -3403-OOOCN 8-6 Plate, Gear Plate Ground RBI -2974-OOOCN 8-6 Plate, Ground RBI -3164-OOOCN 8-7 Plate, Grounding, LJ 4P/4MP RBI -3417-OOOCN 8-3 Plate, Side RF5-0637-OOOCN 8-10 Plate, Solenoid Ground RBI -3152-OOOCN 8-7 Plunger Lock, Door RBI -3002-OOOCN 8-6 Power Switch RG5-0805-OOOCN 8-4 RFI Shield, Control Panel PCA, LJ 4P/4MP RB1 -3416-OOOCN 8-3 RFI Shield, LJ 4L C2003-00032 8-4 RFI Shield, LJ 4ML, Mini DIN C2015-00003 8-4 RFI Shield, LJ 4ML C2015-00002 8-4 RFI Shield, LJ 4P/4MP C2005-00013 8-4 ● Roller Assy, Small Media, LJ 4P/4MP RG5-0794-OOOCN 8-6 Roller, Delivery RB1 -3107-OOOCN 8-12 Roller, Fuser Conductive Rubber RBI -3109-OOOCN 8-12 Roller, Fuser Delivery RB1-3103-OOOCN 8-12 ● Roller, Fuser Pressure RBI -3100-OOOCN 8-12 Roller, Lower Output Assembly RG5-0682-OOOCN 8-5 Roller, Transfer Assembly RF5-0596-OOOCN 8-5 ● Parts Index-6, Parts Index Alphabetical Parts Index DESCRIPTION PART NUMBER FIG ● Roller, Upper Output Assembly RG5-0683-OOOCN 8-5Scanner Connector Assembly RG5-0766-OOOCN 8-5 Parts Index-7, Parts Index Alphabetical Parts Index a DESCRIPTION PART NUMBER FIG Spring, Leaf, LJ 4U4ML RBI -3125-OOOCN 8-8 Sprino, Leaf, LJ 4P/4MP RB1 -3402-OOOCN 8-8 ● Parts Index-8, Parts Index Numerical Parts Index arts Index DESCRIPTION FIG Screw, washer-head, short (8 mm) 8-4 Screw, washer-head, long (12 mm) 8-4 DC Controller Connector, LJ 4L/4ML 8-4 1252-5460 DC Controller Connector, LJ 4P/4MP 8-4 C2003-00005 Nameplate, LJ 4L 8-2 C2003-00032 RFI Shield, LJ 4L 8-4 C2003-40001 Switch Acutuator, LJ 4UML 8-4 C2003-69001 Fuser Assembly, 100-120V (Exchange) 8-12 C2003-69002 Fuser Assembly, 220-240V (Exchange) 8-12 C2003-69003 DC Controller PCA, 100-120V, LJ 4U4ML (Exchange) 8-7 C2003-69004 DC Controller PCA, 220-240V, LJ 4L/4ML (Exchange) 8-7 C2003-69005 Laser/Scanner Assemblv, LJ 4U4ML (Exchange) 8-6 C2004-67901 Formatter PCA, LJ 4L (New) 8-4 C2004-69001 ‘Formatter PCA, LJ 4L (Exchange) I 8-4 C2005-00001 Nameplate, LJ 4P C2005-00004 Font Guide, LJ 4P/4MP C2005-00013 RFI Shield, LJ 4P/4MP C2005-40001 l/O Cover Plate, LJ 4P KeVboard Overlay, Euro-English Keyboard Overlay, Turkish Kevboard Overlav, Portuguese C2005-40005 Keyboard Overlay, German C2005-40006 Keyboard Overlay, Spanish ● EC2005-40007 Keyboard Overlay, FrenchC2005-40008 Keyboard Overlay, ItalianC2005-40009 Keyboard Overlay, Dutch● C2005-4001 O Keyboard Overlay, Norwegian Parts Index-9, Parts Index Numerical Parts Index PART NUMBER DESCRIPTION FIG C2005-40011 Keyboard Overlay, Polish 8-13 C2005-40012 Keyboard Overlay, Swedish 8-13 ● C2005-40013 Keyboard Overlay, Finnish 8-13 C2005-40014 Keyboard Overlay, Danish 8-13 C2005-40017 Keyboard Overlay, Chinese 8-13 ● C2005-40018 Keyboard Overlay, Taiwanese 8-13 C2005-69003 DC Controller PCA, 100-120V, LJ 4P/4MP (Exchange) 8-7 C2005-69004 DC Controller PCA, 220-240V, LJ 4P14MP (Exchange) 8-7 C2005-69005 Laser/Scanner Assembly, LJ 4P/4MP (Exchan~e) 8-6 C2006-67901 Formatter PCA, LJ 4P (New} 8-4 C2006-69001 Formatter PCA, LJ 4P (Exchange) 8-4 C2015-00001 Nameplate, LJ 4ML 8-2 C201 5-00002 RFI Shield, LJ 4ML 8-4 C2015-00003 RFI Shield, LJ 4ML, Mini DIN 8-4 C2016-67901 Formatter PCA, LJ 4ML (New) 8-4, C2016-69001 Formatter PCA, LJ 4ML (Exchange) 8-4 C2040-00001 Nameplate, LJ 4MP 8-3 C2040-40001 l/O Cover Plate, LJ 4MP 8-3. C2040-40002 Font Door Plug, LJ 4MP only 8-3 C2041 -67901 Formatter PCA, LJ 4MP (New) 8-4 C2041 -69001 Formatter PCA, LJ 4MP (Exchange) 8-4 R75-001 O-OOOCN Universal Paper Cassette, LJ 4U4ML 8-9 R75-201 O-OOOCN Universal Pa~er Cassette, LJ 4P14MP 8-10 @ RBI -2971 -OOOCN Bushing, D-roller 8-6 RB1 -2974-OOOCN Plate, Gear Plate Ground 8-6 RBI -2976-OOOCN Light Pipe, LJ 4U4ML 8-2 RB1-2977-OOOCN Door, 1/0, LJ 4U4ML 8-2 ● RBI-2978-OOOCN Door, Power, LJ 4U4ML 8-2 RBI-2979-OOOCN Door, Memory, LJ 4U4ML 8-2 a Parts Index-10, Parts Index Numerical Parts Index @ I PART NUMBER I DESCRIPTION I FIG ● RBI -2981 -OOOCN Tab, Fuser Release 8-12RBI-2984-OOOCN Plate, Fuser Ground, LJ 4L14ML 8-6 RB1 -2987-OOOCN Shield, High Voltage 8-6 RBI -3001 -OOOCN Foot, Chassis 8-6 RB1 -3002-OOOCN Plunger Lock, Door 8-6 m RBI -3003-OOOCN Spring, Scanner Leaf 8-6 RBI -3029-OOOCN Pickup Feed D-Roller, LJ4U4ML 8-11 RBI -3004-OOOCN Plate, CRG 8-6 RB1 -3073-OOOCN Bushing 8-5 RB1 -3097-OOOCN Flag, Exit Sensor 8-12 RB1 -3100-OOOCN Roller, Fuser Pressure 8-12 RBI -3103-OOOCN Roller, Fuser Delivery 8-12 RBI -3107-OOOCN Roller, Delivery 8-12 RBI -3108-OOOCN Spring, Delivery 8-12 RB1 -3109-OOOCN Roller, Fuser Conductive Rubber 8-12 RBI -3125-OOOCN Spring, Leaf, LJ 4L14ML 8-8 RBI -3128-OOOCN Front Panel Button, LJ 4U4ML 8-2 RBI -3129-OOOCN Door, Top, LJ 4U4ML 8-2 RBI -3130-OOOCN CRG Pressure Piece, LJ 4L14ML 8-2 RB1 -3130-OOOCN CRG Pressure Piece, LJ 4P/4MP 8-3 RBI -3131 -OOOCN Shaft, Top Door Hinge, LJ 4U4ML 8-2 RB1-3131-OOOCN Shaft, Top Door Hinge, LJ 4P14MP 8-3 a RBI -3132-OOOCN Button, Lock, LJ 4L14ML 8-2 RBI -3133-OOOCN Guide, Lock Button, LJ 4U4ML 8-2 RB1 -3134-OOOCN Spring, Left Torsion, LJ 4U4ML 8-2 9 RB1 -3135-OOOCN Spring, Right Torsion, LJ 4U4ML 8-2RBI -3138-OOOCN Spring, Torsion, LJ 4L14ML 8-2 RB1 -3138-OOOCN Spring, Torsion, LJ 4P14MP 8-3 RBI -3142-OOOCN Guide, Forms Size /8-9 ● ’ Parts Index-n, Parts Index Numerical Parts Index PARTNUMBER DESCRIPTION FIG RBI-3143-OOOCN Claw, Separation 8-10 RBI-3143-OOOCN Claw, Separation 8-9 : ● RBI-3151-OOOCN Spring, Cassette Side 8-7 RB1 -3152-OOOCN Plate, Solenoid Ground 8-7 RBI -3164-OOOCN Plate, Ground 8-7 ~ a RBI -3332-OOOCN Door, Top, LJ 4P14MP 8-3- RB1 -3338-OOOCN Plate, End 8-10 RB1 -3339-OOOCN Lever 8-10 RB1 -3341 -OOOCN Tray, Leqal 8-10 RB1 -3352-OOOCN Cover, Font, LJ 4P14MP 8-3- RBI -3353-OOOCN Hinge, Font Cover, LJ 4P14MP 8-3 RB1 -3356-OOOCN Button, Lock, LJ 4P14MP 8-3 RBI -3357-OOOCN Guide, Lock Button, LJ 4P14MP 8-3. RBI -3365-OOOCN Shaft Holder, LJ 4P14MP 8-6- RBI -3368-OOOCN Picku~ Feed D-Roller 8-11 RB1 -3392-OOOCN Dust Cover, Foam Rubber 8-6- RB1 -3402-OOOCN Spring, Leaf, LJ 4P14MP 8-8 RB1 -3403-OOOCN Plate, Fuser Ground, LJ 4P14MP 8-6 RB1 -3404-OOOCN Grounding Plate, LJ 4P14MP 8-4 RBI-3405-OOOCN Grounding Plate, LJ 4P14MP 8-4 RB1 -3416-OOOCN RFI Shield, Control Panel PCA, LJ 4P14MP 8-3 RBI -3417-OOOCN Plate, Grounding, LJ 4P14MP 8-3 RB1 -3681 -OOOCN Cap, Laser Shutter 8-6 - ● RBI -3798-OOOCN Spring, Left Torsion, LJ 4P14MP 8-3 RBI-3799-OOOCN Spring, Right Torsion, LJ 4P/4MP 8-3 RF5-0584-OOOCN Static Eliminator Assembly 8-6 RF5-0585-OOOCN Transfer Guide 8-5 m RF5-0596-OOOCN Roller, Transfer Assembly 8-5 Parts Index-12, Parts Index Numerical Parts Index ● PART NUMBER DESCRIPTION FIG RF5-0597-OOOCN Cover, Main, LJ 4U4ML 8-2 RF5-0601-OOOCN Arm, Input Paper Sensor 8-6 RF5-0637-OOOCN Plate, Side 8-10 RF5-0681-OOOCN Cover, Main, LJ 4P/4MP 8-3 RF5-0682-OOOCN Bezel Assembly, LJ 4P/4MP 8-3 RG5-0662-OOOCN Laser/Scanner Assembly, LJ 4U4ML (New) 8-6 RG5-0667-OOOCN Beam-to-Drum Mirror Assembly, LJ 4U4ML 8-5 RG5-0668-OOOCN Pickup Assembly, LJ4U4ML 8-11 RG5-0669-OOOCN Front Oblique Roller Assembly 8-4 RG5-0670-OOOCN ToP Oblique Roller Assembly 8-6: RG5-0671 -OOOCN Guide, Feeder Assembly, LJ 4U4ML RG5-0672-OOOCN Switch, Cam Assembly RG5-0674-OOOCN Mount, Transfer Assembly, Left RG5-0675-OOOCN Mount, Transfer Assembly, Right RG5-0676-OOOCN Fuser Assembly, 100-120V (New) RG5-0677-OOOCN Fuser Assembly, 220-240V (New) RG5-0678-OOOCN Fuser Film Assv, 100/120V RG5-0679-OOOCN Fuser Film Assy, 220/240V RG5-0681-OOOCN Fuser Delivery Assembly RG5-0682-OOOCN Roller, Lower Output Assembly RG5-0683-OOOCN Roller, Upper Output Assembly RG5-0684-OOOCN Gear Train Plate AssemblV, LJ 4L/4ML RG5-0685-OOOCN Cover Assembly, LJ 4U4ML RG5-0690-OOOCN Guide, Fuser Entrance RG5-0691-OOOCN Door, Back Assembly, LJ 4U4ML RG5-0691 -OOOCN Door, Back Assemblv, LJ 4P/4MP RG5-0694-OOOCN Switch, Plunger Assembly RG5-0700-OOOCN DC Controller Case AssemblV RG5-0701-OOOCN High Voltage Connector Assembly Parts Index-13, Parts Index Numerical Parts Index PARTNUMBER DESCRIPTION FIG RG5-0702-OOOCN Transfer Guide Assembly 8-5 RG5-0703-OOOCN Fan Assembly 8-4 ● RG5-0753-OOOCN DC Controller PCA, 100-1 20V, LJ 4L14ML (New) 8-7 RG5-0764-OOOCN Motor, Main Assembly 8-5 RG5-0766-OOOCN Scanner Connector Assembly 8-5 ● RG5-0767-OOOCN DC Controller PCA, 220-240V, LJ 4L14ML (New) 8-7 RG5-0791 -OOOCN Gear Train Plate Assembly, LJ 4P14MP 8-8 RG5-0793-OOOCN Guide, Feeder Assembly, LJ 4P14MP 8-6 RG5-0794-OOOCN Roller Assy, Small Media, LJ 4P14MP 8-6 RG5-0796-OOOCN Pickup Assembly 8-11 RG5-0800-OOOCN Laser/Scanner Assembly, LJ 4P14MP (New) 8-6 RG5-0802-OOOCN Beam-to-Drum Mirror Assembly, LJ 4P14MP 8-5 RG5-0805-OOOCN Power Switch 8-4 RG5-O81O-OOOCN Cover Assembly, LJ 4P14MP 8-3 RG5-0812-OOOCN Control Panel Assembly, LJ 4P14MP 8-3 RG5-0813-OOOCN SIMM Cover Assembly, LJ 4P14MP 8-3 RG5-0815-OOOCN Display Cable, LJ 4P14MP 8-3 RG5-0816-OOOCN Control Panel PCA, LJ 4P14MP 8-3 RG5-0822-OOOCN DC Controller PCA, 100-1 20V, LJ 4P14MP (New) 8-7 RG5-0823-OOOCN DC Controller PCA, 220-240V, LJ 4P14MP (New) 8-7 RH7-5092-OOOCN Paper Feed Solenoid (SL1 ) 8-7> RS5-0364-OOOCN Drive Gear, LJ 4P14MP 8-6 R~5-2224-OOOCN Spring, Fuser Hook 8-12 ● RS5-2227-OOOCN Spring, Top Door Compression, LJ 4U4ML 8-2 RS5-2227-OOOCN Spring, Top Door Compression, LJ 4P14MP 8-3 RS5-2228-OOOCN Spring, Top Door Latch, LJ 4U4ML 8-2 RS5-2228-OOOCN Spring, Top Door Latch, LJ 4P14MP 8-3 ● RS5-2229-OOOCN Spring, Compression Small 8-9 Parts Index-14, Paris Index Numerical Parts Index PART NUMBER DESCRIPTION FIG RS5-2230-OOOCN Spring, Compression Larqe 8-9 a RS5-2232-OOOCN Sprina, Compression 8-6 RS5-2254-OOOCN Spring, Compression Small 8-10 RS5-2255-OOOCN Spring, Font Door Torsion, LJ 4P14MP 8-3 RS5-2256-OOOCN Spring, Compression Large 8-10 a VD7-0522-501 CN Fuse FU201, 100-120V ONLY 8-7 VD7-0643-151 CN Fuse FU1 01, 220-240V 8-7 WD1-0288-OOOCN Fuse FUIO1, 100-120V 8-7 XA9-0495-OOOCN Screw, Main Motor 8-5 XA9-0634-OOOCN Screw, Top Door, LJ 4U4ML 8-2 XA9-0634-OOOCN Screw, Top Door, LJ 4P14MP 8-3 XA9-0653-OOOCN Screw, M3X6 8-6 XA9-0654-OOOCN Screw, M3X1 O 8-4 XB2-7300-606CN Screw, wlstar washer (M3X6) 8-8 XB2-8300-809CN Screw, wlstar washer (M3X8) 8-12 XB4-7401-007CN M4x1 O Screw 8-1 XB4-7401-209CN M4XI 2 Screw, Scanner 8-6 XB1-2300-607CN M3x6 Solenoid Screw 8-7 XD2-1 100-242CN E-Clip, LJ 4L14ML 8-2. XD2-1 100-242CN E-Clip, LJ 4P14MP 8-3 XD2-2300-402CN Washer, SE Ring, LJ 4L14ML 8-2 Parts Index-15, Parts Index Numerical F’arb Index ● ● e Parts Index-16, Appendk B 170IMorrnation, 1/0 Information Bi-Tronics Parallel Cable Information

Bi-’Ikonics Parallel Cable Information

● The Bi-Tronics parallel interface is compatible with Centronics parallel interfaces. To take advantage of its enhanced capabilities — such as hi-directional communication between the comtmter and printer, faster transmission of data, and auto con&urati& of printer drivers — the customer must have: ● Support in software applications for these features. ● A parallel cable with the correct pin configuration (see below), Parallel Cable Pin Configuration For best results, use the C24542D cable, or equivalent. Most existing parallel cables support Bi-Tronics communication, but some might have incompatible pin assignments.

CAUTION Ensure that all power and interface cables on

the printer and host computer are properly grounded in compliance with local codes. Signal Name Printer Pin # IBM Pori Pln # nSTROBE DATA 1 ; ; DATA23DATA 3 : 4 DATA45DATA56: DATA677DATA788DATA 8 &A:@NLG 1: 1: 11 11 CALL (PE) 12 12 SELECT 13 nAutoFd 14 {2 :FA~& (GND) 19 THRU SO 18 THRU 25 32 15 nSelIn 36 17 - .—.FigN’e B-1 parallel came Pm Assignments B-2, 1/0 Information Serial Cable Pin Configurations (LaserJet 4W4MF’)

Serial Cable Pin Configurations

(LaserJet 4P/4MP) The following table diagrams show the cable pinouts for the most common serial configurations. DB-9 Serial Connection If connecting to a computer with a 9-pin serial port, use the HP C2932A 9-9 pin M/F serial cable, or equivalent. FEMALE DB-9 TO MALE DB9 CABLE

HOST

COMPUTER FEMALE H~@~SB~[R Shall~ shell

P

FigureEM Serial Pin-Outs DEW to DB-9

DB-25 Serial Connection

If connecting to a computer with a 25-pin serial port, use the HP C2933A 9-25 pin M/F serial cable, or equivalent.

I FEMALE DB-25 TO MALE DB-9 CABLE F C&mx.m. FEMALE MALE PRINTER

T DS-25 0S-9II..- TsD + 2- MALE g= 4 FEMALE DB25 5DTR ~ DE-9

R. R+

; 0 in ~ ‘ ~ &@) “ “’” ““~ dlsli~sh’sdl ‘igure B-3 Serial Pin-Ck4ts DEL25 to IX-9 B-3, 1/0 Information Connecting to LocalTalk Networks (LaserJet 4ML/ 4MP)

Comecting to LocalTalk Networks

(LaserJet 4MU 4MP) The printer does not come with a LocalTalk network cable. Use a standard LocalTalk network cable and connector kit, such as the HP LocalTalk Network Cable Kit, part number 92215N. You will need one connector kit for each printer on the network, and another for each Macintosh computer on the network.

Connecting to the END of a LocalTalk Network

Figure B-4 Connecting to the END of a LocalTalk Network 1. Disconnect the printer from its power source. Insert the connector box cable into the LocalTalk port of the printer. 2. Insert one end of the cable into the new connector box. 3. If the connector box is not self-terminating, insert a terminating resistor into the connector box. 4. Insert the other end of the cable into the last connector box on the network. (Remove the terminating resistor if necessary.) 5. Reconnect the printer to its power source. — B-4, 1/0 Information Connecting to LocalTalk Networks (LaserJet 4ML/ 4MP)

Connecting to the MIDDLE of a LocalTalk Network

1. Disconnect the printer from its power source. Insert the new connector box cable into the LocalTalk port of your printer. 2. Insert one end of the new cable into the connector box. 3. Place the other end of the new cable next to a connector box on the network. 4. Unplug one cable from the connector box on the network. c1— ~ c1. @ @ FigureEM connectintogthe MIDDLEd a Locawalk Nshw’k (WTwJd) 5. Insert the new cable into the connector box on the network. 6. Insert the cable you removed from the network into the new connector box. Then, reconnect the printer to its power source. B-5, 1/0 Information Connecting to LocalTalk Networks (LaserJet 4ML/ 4MP) B-6,

Inckx Ihnldex

o-9 assemblv 50 SERVICE (Fuser Error) 7-12 Be;m to Drum Mirror 6-29 51 ERROR (Beam Error) 7-13 DC Controller 6-39 52 ERROR (Scanner Error) 7-13 DC Controller/Scanner Connector 53 ERROR (RAM/ROM Error) 7-14 6-54 55 ERROR (Engine Error) 7-15 Feeder Guide 6-49 57 ERROR (Main Motor Error) 7-15 Form Guide 6-21 58 SERVICE (Fan Error) 7-16 Fusing 6-30 60-67 SERVICE (Formatter Error) 7-16 Gear Train 6-17 70-71 ERROR (Formatter Error) 7-16 High Voltage Connector 6-42 72-79 SERVICE (Formatter Error) 7-16 Laser/Scanner 6-23 68 ERRORISVC (- Error) 7-12 Paper Cassette 6-21 Paper Guide/Top Oblique Roller A 6-26 ac power distribution 5-8 Pickup 6-47 accessories and supplies 8-5-8-26 Plunger, Top Door Switch 6-53 adhesive label specifications 2-13 Small Media Roller 6-50 adjustment Static Eliminator Strip 6-51 beam-to-drum mirror 7-44 Toner Cartridge Lever 6-52 leading edge 7-43 Upper Output-Roller 6-37 print skew 7-44 Assist Line (HP CSC) 1-21 adjustment procedures 7-43-7-45 assistance, technical 1-20-1-22 advanced fimctions, I/O (theory) 5-14 Audio Tips, HP 1-21 Appletalk 1-2 ASAP (Automated Support Access Pro- B gram) 1-20 beam error (51 ERROR) 7-13 assemblies Beam-to-Drum Mirror Assembly 6-29 bottom 6-39-6-56 Beam-to-drum Mirror adjustment 7-44 front 6-20-6-22 bi-tronics parallel cable B-2 internal 6-23-6-29 Bottom Assemblies 6-39-6-56 left side 6-15-19 button, front panel overview 3-9 rear 6-30-38 button, front panel usage 3-11 user installable 6-4 -6-5 a ccapacities: input tray 1-2capacities: output tray 1-2 ca@idge slots 1-2 CDRH (Center for Devices and Radiologi- cal Health) 1-11 checkpoints, service 4-2 CIC (Customer Information Center) 1-21 ● class 1 laser product 1-11class B digital device 1-15 cleaning printer components 4-6- 4-7 spilled toner 4-7 cleaning stage (theory) 5-25 ● clearable warnings (LJet 4P/4MP) 7-18

Index-1

,

Index

clearing paper jams 4-8-4-12 drum sensitivity (theory) 5-24 inside the printer 4-IO duty cycle 1-2 paper feed area 4-9 paper output area 4-12 E cold reset 3-28 EconoMode 3-21,4-5 cold reset default (LJet 4P/4MP) 3-18 EconoMode (theory) 5-18 common hardware 8-4 electrical s~ecifications 1-4 comparison, features 1-2 end-of-job, ~ront panel command 3-10 complex pages message 3-10 engine error (55 ERROR) 7-15 compression springs, paper cassette 6.22 en@ne test 3-25, 7-36-7-38 CompuServe Forum, HP 1-21 button location 7-36 conditioning stage (theory) 5-26 microswitch (SW301) (theory) 5-7 conformity,-declaration o; 1-13 envelope and paper sizes 2-9 consumables, life expectancy 4-3 -4-5 envelope capability 1-2 consumables, ordering 8-3 envelope specifications 2-12 continuous self test 3-24 environment control errors 3-21 operating 2-2 control panel (LaserJet 4P/4MP) Error light 3-10 display and lights 3-13 error messages overview 3-12 memory (complex page) 3-10 control panel (theory) 5-16 paper cassette empty 3-10 control panel, using 3-9-3-14 paper jam 3-10 cover and doors, removal & replace- toner missing 3-10 ment 6-6-6-14 top door open 3-10 CPU, printer (theory) 5-13 troubleshooting 7-6-7-18 CSC (Customer Support Center) 1-21 European Custome; Support Center Customer Support Center (CSC) 1-21 (ECSC) 1-22 Customer Support Center, Europe exchange program 1-17 (ECSC) 1-22 external assembly locations 1.6- I-7 , D F damage, shipping 3-3 fan (removal & replacement) 6-24 Data light 3-10 fan error (58 SERVICE) 7-16 data loss 3-10 fan motor (theory) 5-7 DC Controller Assembly 6-39 fax information service (HP FIRST) 1-20 DC Controller diagram 7-5 FCC statement 1-15 DC Controller Fuses 6-42 features comparison 1-2 DC Controller PCA 6-43 Feeder Guide Assembly 6-49 DC Controller/power system 5-3-5-11 Finland laser statement 1-12 DC Controller/Scanner Connector 6-54 fiiware datecode 3-21 dc power distribution 5-8 flicker effect (room lights) 2-2 declaration of conformity 1-13 font selection 3-21 default settings (on self test) 3-20-3-21 fonts, internal 1-2 delay jams (theory) 5-39 form feed, front panel command 3-10 Department of Health and Human Serv- Form Guide Assembly 6-21 . ices (DHHS) 1-11 Formatter error (60-67 SERVICE) 7-16 developing stage (theory) 5-29 Formatter error (70-71 ERROR) 7-16 DHHS 1-11 Formatter error (72-79 SERVICE) 7-16 diagnostics, service menu item 3-18 Formatter PCA 6-15 Dir;ct Marketing Division (DMO) 8-3 Formatter Shield 6-15 DMO 8-3 Formatter system (theory) 5-12-5-21 documentation, related 1-18 front assemblies 6-20-6-22 door open, control panel message 3-10 drum rotation functional check ‘j’-4o

Index-2

, Irick?x front panel button J clearing error states 3-10 Japanese VCCI Statement 1-16 overview 3-9 resuming after memory error 3-10 L usage table 3-11 laser and scanner drive (theory) 5-5 functions, basic printer (theory) 5-2 laser statement, Finland 1-12 fuser error (50 SERVICE) 7-12 Laser/Scanner Assembly 6-23 fuses, DC Controller 6-42 leading edge adjustment 7-43 Fusing Assembly 6-30 LEDs 3-10 fusing stage (theory) 5-32 left side assemblies 6-15-6-29 life expectancy of consumables 4-3- 4-5 G lights, room (flickering effect) 2-2 Gear Train Assembly 6-17 lights (LEDs), functions 3-10 loading the paper cassette 3-4 H LocalTalk feature 1-2 half self test functional check 7-39 LocalTalk cabling information B-4 - B-6 hardware, common 8-4 LocalTalk 1% (theory) 5-15 help labels 3-6 Lower Output Rollers 6-38 help labels installation 3-6 high speed, parallel I/O (theory) 5-14 M High Voltage Connector Assembly 6-42 Main Motor 6-16 high voltage distribution (theory) 5-11 main motor error (57 ERROR) 7-15 high-voltage power supply check 7-41 main motor (theory) 5-7 HP ASAP (Automated Swmort Access main wiring diagram 7-47-7-48 Program) 1-20 ‘ ‘ maintenance 4-1-4-12 HP AUDIO TIPS 1-21 Manual Feed mode HP Explorer drivers disk, using 3-8 control panel message 3-10 HP FIRST (Fax Information Retrieval manual feed printing (theory) 5-38 Support Technology) 1-20 Material Safety Data Sheet (MSDS) 1-14 matrix, printer features 1-2 1 media selection guidelines 2-10 UO Door 6-6 media specifications 2-8-2-16 identification, printer 1-3 memory configuration 3-21 Image Adapt (theory) 5-20 Memory Door 6-6 image formation memory enhancement technology (MEt) (theory) 5-22-5-32 (theory) 5-19 troubleshooting 7-19-7-35 memory error image skew adjustment 7-44 control panel message 3-10 indicator lights 3-10 memory management (theory) 5-19 Input Paper Sensor, PS 1 (theory) 5-36 memory upgrade 6-4 Input Paper Sensor Arm 6-56 when needed 3-10 input trays 1-2 memory, standard & optional 1-2 intelligent on/off (theory) 5-10 memoryflanguage SIMMS 6-5 installation menu of resets 3-27 and configuration 3-1-3-30 monthly usage 1-2 help labels 3-6 motors (theory) 5-7 power cord 3-5 MSDS 1-14 printer 3-2 -3-8 printer drivers 3-7 N toner cartridge 3-3 non-volatile memory (NVRAM) (theory) interface cables, attaching 3-4, B-4 - B-6 5-14 internal assemblies 6-23-6-29 NVRAM error (68 ERROR) 7-12 internal assembly locations 1-8 NVRAM Reset 7-17

Index-3

,

Index

o PCA Oblique Roller Assembly, Front 6-20 Control Panel (LJet 4P/4MP) 6-13 operating environment 2-2 DC Controller 6-43 operating requirements 2-1-2-16 Formatter 6-15 optional printer memory 3-10 PCE 1-17,8-2 ordering performance specifications 1-4 consumables 1-17, 8-3 phone numbers parts 1-17, 8-2 CIC (Customer Info Center) 1-21 related documentation 1-18 consumables 8-3 overcurrent protection (theory) 5-10 CSC (Customer Support Ctr) 1-21 overhead transparency specs 2-15 DMO 8-3 ozone emission 1-14 PCE 8-2 PDO 8-2 P printer drivers 3-7 Pacing, serial I/O (theory) 5-15 technical assistance 1-20-1-22 page count (LaserJet 4P/4MP) 3-17 photosensitive drum (theory) 5-23 page coverage, 5% 4-4 photosensors (theory) 5-35 page protect 3-10 Pickup Assembly 6-47 page protect (theory) 5-20 Pickup Feed D-Roller 6-46 paper and envelope sizes 2-9 pickup jams (theory) 5-39 paper capacities 1-2 Pickup Solenoid 6-41 Paper Cassette Assembly 3-4,6-21 pin configuration paper cassette empty parallel B-2 control panel message 3-10 serial B-3 paper cassette loading 3-4 PJL Overview (theory) 5-21 paper cassette, printing (theory) 5-37 Plunger Assembly, Top Door Switch 6-53 paper curl 7-42 power cord 3-5 paper feed area, paper jams 4-9 Power Door 6-6 paper feed system (theory) 5-33-5-39 Power Switch 6-25 Paper Guide/Top Oblique Roller 6-26 power system (theory) 5-3-5-11 paper handling 3-21 power-on jams (theory) 5-39 paper jam detection (theory) 5-39 print capacity, toner 4-4 paper jams print density adjustment (theory) 5-17 clearing 4-8-4-12 print engine control (theory) 5-5 continuous, due to PS l/PS2 6-40 print media specflcations control panel message 3-10 envelopes 2-12 paper light 3-10 print quality adjustment 3-21 ~. a~. er motion. monitoring and control m-int skew adjustment 7-44 (theory) ‘5-5 - ~rint speed 1“-2 paper movement, overview (theory) 5-34 print utilities l-lg paper out sensor, PS2 (theory) 5-35 printer serial number 1-3 paper output area, paper jams 4-12 Printer Covers paper path and components 7-4 LaserJet 4L/4ML 6-7 paper sensors (theory) 5-35-5-36 LaserJet 4P/4MP 6-9 paper specifications 2-10 printer dimensions 1-4 parallel cable, bi-tronics B-2 printer drivers 3-7 parallel interface (theory) 5-14 printer drivers, obtaining 3-7 parts, ordering 1-17,8-2 printer error troubleshooting 7-6-7-18 Parts Center Europe (PCE) 1-17,8-2 printer features list 3-21 Parts Direct Ordering (PDO) 1-17,8-2 printer languages 1-2 parts index printer lights, fimctions 3-10 listing by name A-2 - A-8 printer space requirements 2-3 listing by part number A-9 - A-16 printing a self test 3-19-3-24 printing engine test - LJet 41J4ML 7-36

Index-4

,

Index

minting emzine test - LJet 4P/4MP 7-37 removal and re~lacement 6-1 priorit~of elrors 7-7 Beam to D-rum Mirror 6-29 processing data Control Panel (LJet 4P/4MP) 6-13 control panel message 3-10 cover and doors 6-6-6-14 product information 1-1-1-22 DC Controller Assembly 6-39 product overview 1-6-1-10 DC Controller Fuses 6-42 PS1 (theory) 5-36 DC Controller PCA 6-43 PS2 (theory) 5-35 DC ContJScamer Connector 6-53 Fan 6-24 R Feeder Guide Assembly 6-49 radio frequency interference (RFI) 1-15 Formatter PCA 6-15 RAM7ROM error (53 ERROR) 7-14 Formatter Shield 6-15 RAM size 3-21 Front Oblique Roller 6-20 random access memory (RAM) (theory) Fusing Assembly 6-30 5-13 Gear Train Assembly 6-17 read only memory (ROM) (theory) 5-13 High Voltage Connector 6-42 Ready light 3-10 I/O Door 6-6 rear assemblies 6-30-6-38 Input Paper Sensor Arm 6-56 Rear Door 6-12 Laser/Scanner Assembly 6-23 receiving data Lower Output Roller 6-38 control panel message 3-10 Main Motor 6-19 recoverable errors 7-7 Memory Door 6-6 recycling toner cartridges 2-7 memory upgrade 6-4 refilled toner cartridges 2-7 Paper Cassette Assembly 6-21 related documentation 1-18 Paper GuiddTop Oblique Roller 6-26 remanufactured assemblies 1-17 Pickup Assembly 6-47 removal and replacement strategy 6-2 pickup Feed D-Roller 6-46 Pickup Solenoid 6-41 Power Door 6-6 Power Switch 6-25 Printer Cover (LJet 4L/4ML) 6-7 Printer Cover (LJet 4P/4MP) 6-9 Rear Door 6-12 Small Media Roller 6-50 Static Eliminator Strip 6-51 Toner Cartridge Lever 6-52 Top Cover Switch (Plunger) 6-53 Transfer Roller and Guide 6-27 Transfer Roller Buehings 6-28 Upper Output Roller 6-37 repair philosophy 1-17-1-19 repetitive image defect ruler 7-46 re~uired tools ‘6-3 requirements operating 2-1 2-16 site 2-2 -2-3 space 2-3 reset cold 3-28 menu of 3-27 NVRAM 3-29 simrde 3-26 resetting the printer 3-26-3-30

Index-5

,

Index

a Resolution Enhancement technology storing print media 2-16 (REt) (theory) 5-17 strategy, removal and replacement 6-2 resolution, print 1-2 supplies and accessories 8-5-8-26 RFI statement 1-15 SW201 (top door/toner cartridge roller, Small Media 6-50 microswitch) 5-6 ● s SW301 (engine test microswitch)(theory) 5-7 safety information 1-11-1-14 safety, toner 1-14 T caving toner (EconoMode) 4-5 technical assistance 1-20-1-22 scalable typeface list 3-21 test, engine 3-25 ScanJet compatibility 1-2 timing diagram, printer 5-41-5-42 o scanner error (52 ERROR) 7-13 toner cartridge 2-4- 2-7 screws, length (DC Controller) 6-40 cleaning spills 4-7 screws, used in printer 8-4 control panel message 3-10 self test handling suggestions 2-6 continuous 3-24 installation 3-3 engine 3-25 lever assembly 6-52 printing 3-19-3-24 life expectancy 4-4 printout, LaserJet 4L 3-21 open cartridge storage 2-5 printout, LaserJet 4P/4MP 3-23 recycling 2-7 sequence of operation (theory) 5-40 refilled 2-7 Serial I/O (theory) 5-15 storage conditions 2-4 serial number 1-3 toner safety 1-14 service approach 1-17-1-19 tools, required 6-3 service checkpoints 4-2 Top Door Switch (Plunger Assy) 6-53 service errors 7-11 top door/toner cartridge microswitch service mode 3-15-3-18 (SW201) (theory) 5-6 shipping damage 3-3 Transfer Roller and Guide 6-27 shipping print media 2-16 Transfer Roller Bushings 6-28 SIMMS, memoryflanguage 6-5 transferring stage (theory) 5-31 simple reset 3-26 transparency specflcations 2-15 site requirements 2-2 -2-3 troubleshooting flowchart 7-2 skew adjustment 7-44 troubleshooting tools 7-46 skip demo, service menu item 3-18 SL2, Pickup Solenoid 6-41 u Small Media Roller assembly 6-50 unpacking and installation 3-2 -3-8 small media rollers (theory) 5-38 Upper Output Roller Assembly 6-37 software package, printing 3-8 user installable assemblies 6-4 -6-5 solenoid, Pickup (SL2) 6-41 utilities, print 1-19 solenoids (theory) 5-35 v specifications VCCI Statement (Japan) 1-16 printer 1-4- 1-5 printer dimensions 1-4 w adhesive labels 2-13 writing stage (theory) 5-27 electrical 1-4 envelope 2-12 media 2-8-2-16 performance 1-4 trans~arencv 2-15 speed, pri;t 1-2- Static Eliminator Strip Assembly 6-51 status lights, fimctions 3-10 storage conditions, toner cartridge 2-4

Index-6

]

15