Xerox Phaser 7400 Service Manual

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Phaser® 7400

color printer

Service

Manual

Book 1: Print Engine

Phaser® 7400

Color Printer

Service Manual Book 1: Print Engine

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The following servicing instructions are for use by qualified service personnel only. To avoid personal injury, do not perform any servicing other than that contained in the operating instructions, unless you are qualified to do so.

First Printing: August 2005

071-0876-00

Copyright © 2005 Xerox Corporation. All Rights Reserved. Unpublished rights reserved under the copyright laws of the United States. Contents of this publication may not be reproduced in any form without permission of Xerox Corporation.

Copyright protection claimed includes all forms of matters of copyrightable materials and information now allowed by statutory or judicial law or hereinafter granted, including without limitation, material generated from the software programs which are displayed on the screen such as styles, templates, icons, screen displays, looks, etc.

XEROX Other

, The Document Company®, the digital X®, CentreWare®, infoSMART®, Made For Each

, PagePack™, Phaser®, PhaserSMART®, and Walk-Up™ are trademarks of Xerox Corporation in

the United States and/or other countries.

Acrobat PostScript IntelliSelect

, Adobe® Reader®, Adobe Type Manager®, ATM™, Illustrator®, PageMaker®, Photoshop®,

, Adobe Brilliant® Screens, Adobe Garamond®, Adobe Jenson™, Birch®, Carta®,

, Mythos®, Quake®, and Tekton® are trademarks of Adobe Systems Incorporated in the

United States and/or other countries.

Apple

, AppleTalk®, EtherTalk®, LaserWriter®, LocalTalk®, Macintosh®, Mac OS®, TrueType®, Apple

Chancery

, Chicago®, Geneva®, Monaco®, New York® , and QuickDraw® are trademarks of Apple

Computer, Inc. in the United States and/or other countries.

HP-GL

, HP-UX®, and PCL®are trademarks of Hewlett-Packard Corporation in the United States and/or

other countries.

and AIX® are trademarks of International Business Machines Corporation in the United States and/

IBM or other countries.

Windows

, Windows NT®, Windows Server™, and Wingdings® are trademarks of Microsoft Corporation

in the United States and/or other countries.

, NetWare®, NDPS®, NDS®, Novell Directory Services® , IPX™, and Novell Distributed Print

Novell

™

Services

Sun

are trademarks of Novell, Incorporated in the United States and/or other countries.

, Sun Microsystems™, and Solaris® are trademarks of Sun Microsystems, Incorporated in the United

States and/or other countries.

is a trademark of SWOP, Inc.

SWOP

UNIX

is a trademark in the United States and other countries, licensed exclusively through X/Open

Company Limited.

NERGY STAR

As an E

TAR guidelines for energy efficiency. The ENERGY STAR name and logo are registered U.S. marks.

partner, Xerox Corporation has determined that this product meets the ENERGY

PANTONE Publications for accurate color. PANTONE

Colors generated may not match PANTONE-identified standards. Consult current PANTONE

and other Pantone, Inc. trademarks are the property of

Pantone, Inc. © Pantone, Inc., 2000.

ii Phaser 7400 Color Printer Service Manual

Service Terms

Manual Terms

Various terms are used throughout this manual to either provide additional information on a specific topic or to warn of possible danger present during a procedure or action. Be aware of all symbols and terms when they are used, and always read NOTE, CAUTION, and WARNING statements.

Common Acronyms:

The following list defines the acronyms that may be found in this manual.

ADC: Automatic Density Control MCU: Engine Control Board BTR: Bias Transfer Roller NCS: Non-Contact Sensor CRUM: Customer Replaceable Unit

Monitor

CTD: Toner Density Control PL: Corresponds to the FRU Parts List. ESD: Electrostatic Discharge ROS: Laser Scanning Unit IDT: Intermediate Transfer Unit RTC: Charge Roller

Note

A note indicates an operating or maintenance procedure, practice or condition that is necessary to efficiently accomplish a task. A note can provide additional information related to a specific subject or add a comment on the results achieved through a previous action.

PHD: Imaging Unit

Caution

A caution indicates an operating or maintenance procedure, practice or condition that, if not strictly observed, results in damage to, or destruction of, equipment.

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A warning indicates an operating or maintenance procedure, practice or condition that, if not strictly observed, results in injury or loss of life.

Product Terms

Caution: A personal injury hazard exists that may not be apparent. For example, a

panel may cover the hazardous area.

Danger: A personal injury hazard exists in the area where you see the sign.

Safety iii

Symbols Marked on the Product

DANGER high voltage.

Protective ground (earth) symbol.

Hot surface on or in the printer. Use caution to avoid personal injury.

30 min.

The surface is hot while the printer is running. After turning off the power, wait 30 minutes.

Avoid pinching fingers in the printer. Use caution to avoid personal injury.

Use caution (or draws attention to a particular component). Refer to the manual(s) for information.

iv Phaser 7400 Color Printer Service Manual

Power Safety Precautions

Power Source

For 115 VAC printers, do not apply more than 135 volts RMS between the supply conductors or between either supply conductor and ground. For 230 VAC printers, do not apply more than 254 volts RMS between the supply conductors or between either supply conductor and ground. Use only the specified power cord and connector. This manual assumes that the reader is a qualified service technician.

Plug the three-wire power cord (with grounding prong) into a grounded AC outlet only. If necessary, contact a licensed electrician to install a properly grounded outlet. If the product loses its ground connection, contact with conductive parts may cause an electrical shock. A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation.

Disconnecting Power

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Turning the power off using the power switch does not completely de-energize the printer. You must also disconnect the power cord from the printer’s AC inlet. Disconnect the power cord by pulling the plug, not the cord.

Disconnect the power cord in the following cases:

■ if the power cord or plug is frayed or otherwise damaged,

■ if any liquid or foreign material is spilled into the product,

■ if the printer is exposed to any excess moisture,

■ if the printer is dropped or damaged,

■ if you suspect that the product needs servicing or repair,

■ whenever you clean the product.

Safety v

Electrostatic Discharge (ESD) Precautions

Some semiconductor components, and the respective sub-assemblies that contain them, are vulnerable to damage by Electrostatic discharge (ESD). These components include Integrated Circuits (ICs), Large-Scale Integrated circuits (LSIs), field-effect transistors and other semiconductor chip components. The following techniques will reduce the occurrence of component damage caused by static electricity.

Be sure the power is off to the chassis or circuit board, and observe all other safety precautions.

■ Immediately before handling any semiconductor components assemblies, drain

the electrostatic charge from your body. This can be accomplished by touching an earth ground source or by wearing a wrist strap device connected to an earth ground source. Wearing a wrist strap will also prevent accumulation of additional bodily static charges. Be sure to remove the wrist strap before applying power to the unit under test to avoid potential shock.

■ After removing a static sensitive assembly from its anti-static bag, place it on a

grounded conductive surface. If the anti-static bag is conductive, you may ground the bag and use it as a conductive surface.

■ Do not use freon-propelled chemicals. These can generate electrical charges

sufficient to damage some devices.

■ Do not remove a replacement component or electrical sub-assembly from its

protective package until you are ready to install it.

■ Immediately before removing the protective material from the leads of a

replacement device, touch the protective material to the chassis or circuit assembly into which the device will be installed.

■ Minimize body motions when handling unpacked replacement devices. Motion

such as your clothes brushing together, or lifting a foot from a carpeted floor can generate enough static electricity to damage an electro-statically sensitive device

■ Handle IC’s and EPROM’s carefully to avoid bending pins.

■ Pay attention to the direction of parts when mounting or inserting them on

Printed Circuit Boards (PCB’s).

vi Phaser 7400 Color Printer Service Manual

Service Safety Summary

General Guidelines

For qualified service personnel only: Refer also to the preceding Power Safety

Precautions.

Avoid servicing alone: Do not perform internal service or adjustment of this

product unless another person capable of rendering first aid or resuscitation is present.

Use care when servicing with power: Dangerous voltages may exist at several

points in this product. To avoid personal injury, do not touch exposed connections and components while power is on. Disconnect power before removing the power supply shield or replacing components.

Do not wear jewelry: Remove jewelry prior to servicing. Rings, necklaces and

other metallic objects could come into contact with dangerous voltages and currents.

Warning Labels

Read and obey all posted warning labels. Throughout the printer, warning labels are displayed on potentially dangerous components. As you service the printer, check to make certain that all warning labels remain in place.

Safety Interlocks

Make sure all covers are in place and all interlock switches are functioning correctly after you have completed a printer service call. If you bypass an interlock switch during a service call, use extreme caution when working on or around the printer.

Safety vii

Servicing Electrical Components

Before starting any service procedure, switch off the printer power and unplug the power cord from the wall outlet. If you must service the printer with power applied, be aware of the potential for electrical shock.

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Do not touch any electrical component unless you are instructed to do so by a service procedure.

S7300-02

Servicing Mechanical Components

When servicing mechanical components within the printer, manually rotate drive assemblies, rollers, and gears.

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Do not try to manually rotate or manually stop the drive assemblies while any printer motor is running.

S7300-03

Servicing Fuser Components

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This printer uses heat to fuse the toner image to media. The Fuser is VERY HOT. Turn the printer power off and wait at least 5 minutes for the Fuser to cool before you attempt to service the Fuser or adjacent components.

viii Phaser 7400 Color Printer Service Manual

Regulatory Specifications

Xerox has tested this product to electromagnetic emission and immunity standards. These standards are designed to mitigate interference caused or received by this product in a typical office environment.

United States (FCC Regulations)

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy. If it is not installed and used in accordance with these instructions, it may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his/her own expense.

If this equipment does cause harmful 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 receiver.

■ Increase the separation between the equipment and 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/television technician for help.

Any changes or modifications not expressly approved by Xerox could void the user's authority to operate the equipment. To ensure compliance with Part 15 of the FCC rules, use shielded interface cables.

Canada (Regulations)

This Class A digital apparatus complies with Canadian ICES-003. Cet appareil numérique de la classe A est conforme à la norme NMB-003 du Canada.

Safety ix

European Union

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This is a class A product. In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures.

Xerox Corporation declares, under our sole responsibility, that the product to which this declaration relates is in conformity with the following standards and other normative documents:

Low Voltage Directive 73/23/EEC as amended

EN 60950:2000

EN 60825-1:1994+A1:2001+A2:2002

Electromagnetic Compatibility Directive 89/336/EEC as amended

EN 55022:1998 +A1:2000 +A2:2003

EN 55024:1998 +A1:2000 +A2:2003

EN 61000-3-2:2000

EN 61000-3-3:1995 +A1:2001

Radio & Telecommunications Terminal Equipment Directive 1999/5/EC as amended

EN 300 330-2 V1.1.1

EN 300 440-2 V1.1.1

EN 300 489-3 V1.3.1

This product, if used properly in accordance with the user's instructions, is neither dangerous for the consumer nor for the environment.

A signed copy of the Declaration of Conformity for this product can be obtained from Xerox.

x Phaser 7400 Color Printer Service Manual

Manual Organization

The Phaser 7400 Color Printer Service Manual is the primary document used for repairing, maintaining, and troubleshooting the printer. The manual is organized into two books. This volume, Book 1, focuses on the print engine with the exception of providing complete diagnostic and troubleshooting procedure for the printer and all its options. Book 2 focuses on option repair and includes an overview of option theory, option Field Replaceable Unit (FRU) replacement procedures, parts lists, and wiring diagrams. Use Book 2 after you’ve isolated a problem internal to a specific option or when a problem arises at the engine/option interface.

Book 1 - Print Engine

Use Book 1 as your primary resource for understanding the operational characteristics of the print engine. Book 1 describes printer specifications, theory and includes information important to the diagnosis and repair of problems occurring in the print engine and attached options. Book 1 also provides detailed print engine replacement procudures, parts lists, and wiring diagrams.

Book 1 contains these sections:

Introductory, Safety, and Regulatory Information: This section contains

important safety information and regulatory requirements.

Section 1 - General Information: This section contains an overview of the

printer’s operation, configuration, specifications, and consumables.

Section 2 - Theory of Operation: This section contains detailed functional

information on print engine components.

Section 3 - Error Codes and Messages: This section describes the resident

diagnostics available to assist the troubleshooting process. These diagnostics include error codes and messages and Service Usage Profile data stored in the printer. This section provides complete troubleshooting information for the print engine and all it’s options.

Section 4 - General Troubleshooting: Troubleshooting discussions cover the

operation of Power On Self Test (POST), Service Diagnostics, In addition, this section includes troubleshooting methods for situations where no error indicator is available.

Section 5 - Print-Quality Troubleshooting: This section focuses on techniques

to correct image quality problems associated with printer output.

Section 6 - Adjustments and Calibrations: This section provides procedures

for the adjustment of print engine components.

Section 7 - Cleaning and Maintenance: This section provides periodic cleaning

procedures for the printer.

Safety xi

Section 8 - Service Parts Disassembly: This section contains removal

procedures for spare parts listed in the Parts List. A replacement procedure is included when necessary.

Section 9 - Parts List: This section contains exploded views of the print engine

and option FRUs, as well as part numbers for orderable parts.

Section 10 - Wiring Diagrams: This section contains the plug/jack locations and

the wiring diagrams for the print engine.

Appendix A - Reference: This section provides an illustration of the printer’s

menu structure, a listing of printer status codes, and a list of Service Diagnostics tests.

Book 2 - Options

Use Book 2 as a reference when servicing printer options. Book 2 includes information important for the repair or replacement of option components. Use the troubleshooting procedures in Book 1 to diagnose and isolated the problem.

Book 2 contains these sections:

Introductory, Safety, and Regulatory Information: This section contains

important safety information, regulatory requirements, and information about this manual.

Section 1 - General Information: This section contains an overview of the

options available, configuration, specifications and consumables.

Section 2 - Theory of Operation: This section contains functional information

on each option.

Section 3 - General Troubleshooting: This this section includes information

and procedures for troubleshooting optional components.

Section 4 - Adjustments and Calibrations: This section provides procedures

for the adjustment of print engine components.

Section 5 - Service Parts Disassembly:

procedures for parts listed in the option’s Field Replaceable Units (FRUs) Parts List. A replacement procedure is included when necessary.

Section 6 - Parts Lists: This section contains exploded views of the option FRUs,

as well as FRU part numbers.

Section 7 - Wiring Diagrams: This section contains option plug/jack locations

and wiring diagrams.

This section contains removal

xii Phaser 7400 Color Printer Service Manual

Contents

Service Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Symbols Marked on the Product . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

Power Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v

Electrostatic Discharge (ESD) Precautions. . . . . . . . . . . . . . . . . . . . . . . . . vi

Service Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii

Regulatory Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Manual Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

1 General Information

Printer Introduction and Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Printer Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Metered Printing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Parts of the Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Image Processor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Printer Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Hard Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Additional Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Configuration Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

550-Sheet Feeder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

1650-Sheet Feeder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

Duplex Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

Finisher. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

Maintenance Items. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

Consumables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Memory Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Consumable Life Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14

Physical Dimensions and Clearances . . . . . . . . . . . . . . . . . . . . . 1-14

Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

First Print Output Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

Image Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Media and Tray Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18

Contents xiii

2 Theory of Operation

Phaser 7400 Operational Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Imaging Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

LED Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Fuser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Transfer Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Print Process Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Printer Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Print-Quality Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Color Registration Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Automatic Density Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Selective Control: Paper Pick. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Image Transfer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

Fuser Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

Consumable Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Sensor Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Sensors in the Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

Sensor Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

Paper Level Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Paper Present Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Transparent Media Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Automatic Media Thickness Detection . . . . . . . . . . . . . . . . . . . . 2-21

Paper Size Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

Jam Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

Interlock Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

Toner Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

Input Paper Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

Paper Fed from Tray 1 (MPT) . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

Paper Fed from Tray 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30

Paper Fed from Optional Trays . . . . . . . . . . . . . . . . . . . . . . . . . 2-33

Duplex Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35

Output Paper Path. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37

Fuser and Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37

Top Output Tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38

Side Output Tray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38

Finisher/Inverter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38

Drive Assemblies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39

Imaging Unit Drive Motors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39

Transfer Unit Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41

Fuser Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-43

Toner Dispense Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-44

Duplex Drive Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-45

xiv Phaser 7400 Color Printer Service Manual

Chassis Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-46

Basket Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-46

Waste Toner Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-47

Registration Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-48

Exit Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49

Job Offset Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-51

Trays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52

Tray 1 (MPT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52

Universal Trays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-53

Universal Feeder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-54

Side Output Tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-54

Electrical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-55

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-56

Image Processor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-56

Engine Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-56

Registration Sensor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-56

LED Relay Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-56

Imaging Unit Sensor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-57

Motor Driver Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-57

Feeder Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-57

HVPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-58

LVPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-59

Front Sensor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-59

Rear Sensor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-59

Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-60

Solenoids and Clutches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-61

3 Error Messages and Codes

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Accessing Fault History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Status Page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Service Usage Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Servicing Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Messages, Codes, and Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Error Message Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Jam Locator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Error Message Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Using the Troubleshooting Procedures. . . . . . . . . . . . . . . . . . . . 3-15

Measurement Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16

Jam Error Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

Jam at Door A Open Door A to Clear . . . . . . . . . . . . . . . . . . . . . 3-17

Jam at Door A Open Door A to Clear . . . . . . . . . . . . . . . . . . . . . 3-19

Jam at Door A Misfeed at Tray 1 (MPT) . . . . . . . . . . . . . . . . . . . 3-20

Jam at Door B Misfeed at Tray 2. . . . . . . . . . . . . . . . . . . . . . . . . 3-21

Jam at Door C for Tray [3][4][5][6] . . . . . . . . . . . . . . . . . . . . . . 3-23

Jam at Door D Open Door D to Clear . . . . . . . . . . . . . . . . . . . . . 3-25

Contents xv

Jam in Duplex Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26

Jam at Door E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27

Jam Under Imaging Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29

Jam in Fuser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31

Jam at Duplex Entrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33

Jam at Finisher Punch Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35

Jam at Finisher Door H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36

Jam at Finisher Door H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-37

Jam at Finisher Upper Output Tray . . . . . . . . . . . . . . . . . . . . . . 3-38

Jam at Finisher Saddle Stapler. . . . . . . . . . . . . . . . . . . . . . . . . . 3-39

Jam at Finisher Upper Output Tray . . . . . . . . . . . . . . . . . . . . . . 3-40

Jam at Finisher Stapler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-41

Jam at Finisher Door G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

Jam at Finisher Saddle Stapler. . . . . . . . . . . . . . . . . . . . . . . . . . 3-43

Jam at Finisher Upper Output Tray . . . . . . . . . . . . . . . . . . . . . . 3-44

Jam Inside Finisher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-45

Jam at Finisher Entrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-46

Finisher Output Tray Jammed . . . . . . . . . . . . . . . . . . . . . . . . . . 3-47

Door and Cover Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-49

Close Top Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-49

Close Right Door A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50

Close Right Door B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-51

Close Right Door C for Tray [3][4][5][6] . . . . . . . . . . . . . . . . . . 3-53

Close Left Door D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-54

Close Left Door E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-55

Close Finisher Door F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-56

Close Finisher Door H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-57

Close Finisher Door J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-58

Consumable/Routine Maintenance Procedures . . . . . . . . . . . . . . . . . . . 3-59

Replace [C][M][Y][K] Toner Cartridge . . . . . . . . . . . . . . . . . . . . 3-59

Replace [C][M][Y][K] Imaging Unit. . . . . . . . . . . . . . . . . . . . . . 3-60

Replace Transfer Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-61

Replace Waste Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-62

Replace Fuser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-63

Install, Reseat or Lock [C][M][Y][K] Toner Cartridge . . . . . . . . 3-64

Install or Reseat [C][M][Y][K] Imaging Unit . . . . . . . . . . . . . . . 3-65

Install or Reseat Transfer Unit . . . . . . . . . . . . . . . . . . . . . . . . . . 3-66

Install or Reseat Waste Cartridge. . . . . . . . . . . . . . . . . . . . . . . . 3-67

Install or Reseat Fuser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-68

Metered Toner Is not Enabled . . . . . . . . . . . . . . . . . . . . . . . . . . 3-69

Replace Metered [C][M][Y][K] Toner Cartridge . . . . . . . . . . . . . 3-70

xvi Phaser 7400 Color Printer Service Manual

Tray and Media Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-71

Clear Tray 1 (MPT) Riser Plate . . . . . . . . . . . . . . . . . . . . . . . . . . 3-71

Clear Tray [2][3][4][5][6] Riser Plate . . . . . . . . . . . . . . . . . . . . . 3-73

Out of Paper Load Tray 1(MPT) with [size] [type] . . . . . . . . . . . 3-74

Out of Paper Load Tray [2][3][4][5][6] with [size][type] . . . . . . 3-75

Manual Feed [size][type] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-76

Top Output Tray Is Full, Unload Paper . . . . . . . . . . . . . . . . . . . .3-77

Left Side Output Tray Is Full, Unload Paper . . . . . . . . . . . . . . . . 3-78

Finisher Lower Output Tray is Full, Unload Paper . . . . . . . . . . . . 3-79

Finisher Upper Output Tray is Full, Unload Paper . . . . . . . . . . . . 3-80

Open Left Side Output Tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-81

Media Mismatch Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-82

Wrong Paper Size; Load Tray 1 (MPT) with [size][type]. . . . . . . 3-82

Wrong Paper Size; Load Tray 2 with [size][type] . . . . . . . . . . . . 3-83

Wrong Paper Size; Load Tray [3][4][5][6] with [size][type]. . . . 3-84

Wrong Paper Type Load Tray [1 (MPT)][2][3][4][5][6] with

[size][type] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-85

Paper Not Available Load Tray 1 (MPT) with [size] [type] . . . . . 3-86

Paper Not Available; Load Tray 2 with [size][type] . . . . . . . . . . . 3-87

Paper Not Available Load Tray [3][4][5][6] with [size][type] . . . 3-88

Configuration Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-89

Invalid or Missing Configuration Card . . . . . . . . . . . . . . . . . . . . 3-89

Duplicate IP Address Detected . . . . . . . . . . . . . . . . . . . . . . . . . . 3-89

Fatal Error Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-90

Fuser Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-90

Temp Sensor Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-92

RH Sensor Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-93

LED Over Temperature Failure . . . . . . . . . . . . . . . . . . . . . . . . . . 3-94

Motor Overheating Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-95

Engine Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-96

Power Supply Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-97

Feeder Home Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-98

Controller Fan Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-99

Power Supply Fan Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-100

Top Cover Cooling Fan Failure . . . . . . . . . . . . . . . . . . . . . . . . . 3-101

Imaging Unit Fan Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-102

Transfer Unit Fan Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-103

Engine Cavity Fan Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-104

Duplex Interface Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-105

Tray [3][4][5][6] Interface Failure. . . . . . . . . . . . . . . . . . . . . . . 3-106

Inverter Unit Interface Failure . . . . . . . . . . . . . . . . . . . . . . . . . . 3-107

[C][M][Y][K] LED Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-108

[C][M][Y][K] Imaging Unit Failure . . . . . . . . . . . . . . . . . . . . . . 3-109

Flash Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-111

Fuser Fan Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-112

Fuser 110v/220v Mismatch Failure. . . . . . . . . . . . . . . . . . . . . . 3-113

Contents xvii

Unsupported Duplex Unit ROM . . . . . . . . . . . . . . . . . . . . . . . . 3-114

Unsupported Tray 2 ROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-115

Unsupported Tray [3][4][5][6] ROM . . . . . . . . . . . . . . . . . . . . 3-116

Unsupported Inverter Unit ROM . . . . . . . . . . . . . . . . . . . . . . . 3-117

Unsupported Finisher Unit ROM . . . . . . . . . . . . . . . . . . . . . . . 3-118

Hard Drive Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-119

Fuse Cut Error In Fuser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-120

Fuse Cut Error In Transfer Unit . . . . . . . . . . . . . . . . . . . . . . . . 3-121

Fuse Cut Error In [C][M][Y][K] Imaging Unit. . . . . . . . . . . . . . 3-122

Controller to Engine Communications Failure . . . . . . . . . . . . . 3-123

Finisher Fold Position Sensor Failure. . . . . . . . . . . . . . . . . . . . 3-124

Finisher Paddle Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-125

Finisher Stapler Swing Motor Failure . . . . . . . . . . . . . . . . . . . . 3-126

Finisher Stack Handling Motor Failure . . . . . . . . . . . . . . . . . . . 3-127

Finisher Staple Motor Failure. . . . . . . . . . . . . . . . . . . . . . . . . . 3-128

Finisher Jog Motor Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-129

Finisher Lift Motor Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-130

Finisher Exit Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-132

Finisher Punch Side Registration Sensor Failure . . . . . . . . . . . 3-133

Finisher Punch Registration Sensor Failure . . . . . . . . . . . . . . . 3-134

Finisher Punch Backup RAM Failure . . . . . . . . . . . . . . . . . . . . 3-135

Finisher Punch Communications Failure . . . . . . . . . . . . . . . . . 3-136

Finisher Punch Unit Transfer Motor Failure . . . . . . . . . . . . . . . 3-137

Finisher Punch Motor Failure. . . . . . . . . . . . . . . . . . . . . . . . . . 3-138

Finisher Backup RAM Failure. . . . . . . . . . . . . . . . . . . . . . . . . . 3-139

Finisher Punch Dust Sensor Failure. . . . . . . . . . . . . . . . . . . . . 3-140

Printer Error - Contact Service; report fault [n]. . . . . . . . . . . . . . . . . . 3-141

Finisher Punch Unit Counter at End of Life . . . . . . . . . . . . . . . 3-141

Finisher Staple Unit Counter at End of Life. . . . . . . . . . . . . . . . 3-142

Finisher Interface Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-143

Inverter Power Supply Failure . . . . . . . . . . . . . . . . . . . . . . . . . 3-144

Fuser Thermistor Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-145

Job Offset Home Position Error. . . . . . . . . . . . . . . . . . . . . . . . 3-146

Control Panel Communications Failure . . . . . . . . . . . . . . . . . . 3-147

No Data to the [C][M][Y][K] LED Head . . . . . . . . . . . . . . . . . . 3-148

Motor Driver Board Communications Error . . . . . . . . . . . . . . . 3-149

Tray [3][4][5][6] Firmware Error . . . . . . . . . . . . . . . . . . . . . . . 3-150

Duplex Unit Firmware Error . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-151

Motor Driver Board Firmware Error . . . . . . . . . . . . . . . . . . . . . 3-152

Finisher Inverter Firmware Error . . . . . . . . . . . . . . . . . . . . . . . 3-153

CRUM Reader Board Failure . . . . . . . . . . . . . . . . . . . . . . . . . . 3-154

Tray [3][4][5][6] Flash Memory Failure . . . . . . . . . . . . . . . . . . 3-155

Duplex Unit Flash Memory Failure . . . . . . . . . . . . . . . . . . . . . . 3-156

Motor Driver Board Flash Memory Failure . . . . . . . . . . . . . . . . 3-157

Finisher Inverter Flash Memory Failure . . . . . . . . . . . . . . . . . . 3-158

Tray 2 Lift Motor Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-159

xviii Phaser 7400 Color Printer Service Manual

Tray [3][4][5][6] Lift Motor Failure. . . . . . . . . . . . . . . . . . . . . . 3-160

Error in the Transfer Unit Belt. . . . . . . . . . . . . . . . . . . . . . . . . . 3-162

Duplex Unit Fan Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-163

+24V Not Available to the Duplex Unit . . . . . . . . . . . . . . . . . . . 3-164

Failure in the [C][M][Y][K] Imaging Unit Drum or Motor . . . . . 3-165

+24 V Not Available to Tray [3][4][5][6]. . . . . . . . . . . . . . . . . . 3-167

Failure in the Fuser Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-168

Failure in the Waste Toner Motor . . . . . . . . . . . . . . . . . . . . . . . 3-169

Motor Driver Board Clock Frequency Error. . . . . . . . . . . . . . . . 3-170

Duplex Unit Clock Frequency Error. . . . . . . . . . . . . . . . . . . . . . 3-171

Finisher Inverter Clock Frequency Error . . . . . . . . . . . . . . . . . . 3-172

Tray [3][4][5][6] Feeder Board Clock Frequency Error . . . . . . . 3-173

Waste Toner Transfer Error . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-174

[CM][YK] Toner Supply Failure. . . . . . . . . . . . . . . . . . . . . . . . . 3-176

Warning Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-177

No Paper in Tray 1 (MPT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-177

No Paper in Tray [2][3][4][5][6]. . . . . . . . . . . . . . . . . . . . . . . . 3-178

Left Side Output Tray is Closed. . . . . . . . . . . . . . . . . . . . . . . . . 3-179

Waste Cartridge is Almost Full . . . . . . . . . . . . . . . . . . . . . . . . . 3-180

Non-Xerox [C][M][Y][K] Toner Cartridge . . . . . . . . . . . . . . . . . 3-181

Staple Cartridge Is Empty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-182

Punch Waste Box is Full or Missing . . . . . . . . . . . . . . . . . . . . . 3-183

Finisher Away From Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-184

Finisher Away From Printer. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-185

4 General Troubleshooting

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

System Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Power On Self Test (POST) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

POST Soft Fault Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

POST Hard Fault Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Fault Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Entry Level Fault Isolation Procedure . . . . . . . . . . . . . . . . . . . . . . 4-6

Service Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Using Service Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Service Diagnostics Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Service Diagnostics Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Test Prints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Control Panel Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

No Control Panel Display after Power Is Turned On . . . . . . . . . . 4-10

Control Panel LED Is On, Control Panel Display Is Blank . . . . . . 4-11

Contents xix

Inoperable Printer Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11

Engine Power-Up Sequence (BIST) . . . . . . . . . . . . . . . . . . . . . . 4-12

Printer Continually Displays Warming Up.... . . . . . . . . . . . . . . . 4-13

Printer Displays Install or Reseat Imaging Unit . . . . . . . . . . . . . 4-13

Printer Displays Reseat Contoller Board . . . . . . . . . . . . . . . . . . 4-13

Printer Does Not Come to a Ready State . . . . . . . . . . . . . . . . . . 4-14

Paper Size Switch Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16

AC Power Supply Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16

DC Power Supply Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17

RAM Memory Fault Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17

Media Jams and the Paper Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19

Operating System and Application Problems . . . . . . . . . . . . . . . . . . . . 4-21

Macintosh Printing Problems . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21

Windows Printing Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23

Network Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24

Network Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24

Network Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26

USB Port Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-27

5 Print-Quality Troubleshooting

Print-Quality Problems Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Defects Associated with Specific Printer Components. . . . . . . . . 5-3

Test Prints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Analyzing the 100% Solid Fill Pages . . . . . . . . . . . . . . . . . . . . . . 5-4

Analyzing the Color Test Pages . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

Analyzing the PS Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

Analyzing the Color Step Pages . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

Print-Quality Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

Light Prints in All Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

Light Print in Only One Color. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10

Blank Prints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12

Mottled or Splotchy Prints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14

Unexpected Colors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16

Repeating Bands, Lines, Marks, or Spots . . . . . . . . . . . . . . . . . 5-18

Random Bands, Lines, Marks, or Missing Spots . . . . . . . . . . . . 5-19

Random Spots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21

Background Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23

Residual Image, Ghosting or Hot Offset. . . . . . . . . . . . . . . . . . . 5-25

Incomplete Fusing or Cold Offset. . . . . . . . . . . . . . . . . . . . . . . . 5-27

Mis-Registration, Color Layers Not Correctly Registered. . . . . . 5-28

Toner on Back of Print. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31

Image Not Centered or Positioned Correctly . . . . . . . . . . . . . . . 5-32

Process Direction Bands, Voids, or Streaks. . . . . . . . . . . . . . . . 5-34

Scan Direction Bands, Voids, or Streaks . . . . . . . . . . . . . . . . . . 5-35

Scan Direction Dark Streaks . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37

Process Direction Bands, Voids, or Streaks. . . . . . . . . . . . . . . . 5-38

xx Phaser 7400 Color Printer Service Manual

6 Adjustments and Calibrations

Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Color Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Margin Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Automatic Density Control (ADC) Calibration . . . . . . . . . . . . . . . . 6-2

Automatic Thickness (ATS) Calibration. . . . . . . . . . . . . . . . . . . . . 6-4

Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

Vertical and Horizontal Color Registration . . . . . . . . . . . . . . . . . . 6-5

Resetting NVRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Restore Factory Color Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Restore Previous Color Settings. . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Restore Factory Margins Settings. . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Resetting Connection Setup Defaults . . . . . . . . . . . . . . . . . . . . . . 6-7

Resetting PostScript Setup Defaults. . . . . . . . . . . . . . . . . . . . . . . 6-7

Resetting PCL Setup Values to Default. . . . . . . . . . . . . . . . . . . . . 6-7

Resetting Control Panel Setup Values to Default . . . . . . . . . . . . . 6-8

Resetting Printer Controls Values to Default. . . . . . . . . . . . . . . . . 6-8

Resetting All Printer Defaults (PostScript NVRAM) . . . . . . . . . . . 6-8

Service Diagnostics NVRAM Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9

Postscript NVRAM Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9

CRU Counter Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9

CRU Counter Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9

7 Cleaning and Maintenance

Service Maintenance Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Cleaning the Imaging Unit Contacts . . . . . . . . . . . . . . . . . . . . . . . 7-3

Cleaning the LED Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Cleaning the Feed Rollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

RIP (Repair, Inspect, and Prevent) Procedures . . . . . . . . . . . . . . 7-6

8 Service Parts Disassembly

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

Standard Orientation of the Printer. . . . . . . . . . . . . . . . . . . . . . . . 8-5

General Notes on Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Notations in the Disassembly Text . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Fastener Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

Maintenance Items and Consumables . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8

Imaging Unit Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8

Toner Cartridge Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9

Transfer Unit Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

Fuser Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11

Contents xxi

Print Engine Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12

Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13

Rear Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13

Lower Rear Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

Right Rear Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-15

Right Side Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16

Left Side Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-17

Front Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18

Door B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19

Left Rear Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20

Left Front Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-21

Upper Front Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-22

Right Front Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-23

Top Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-24

Trays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-25

Tray 1 (MPT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-25

Tray 1 (MPT) Level Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-28

Tray 1 (MPT) Home Position Sensor. . . . . . . . . . . . . . . . . . . . . 8-30

OHP Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-31

Feed-Out Sensor #1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-32

Tray 1 (MPT) No Paper Sensor . . . . . . . . . . . . . . . . . . . . . . . . . 8-33

Tray 1 (MPT) Feed Rollers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-34

Tray 2 Feeder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-38

Registration Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-39

Feed Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-40

Lift Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-41

Registration Clutch #2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-42

Door B Detect Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-43

Tray 2 No Paper Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-45

Registration Sensor #2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-47

Feed-Out Sensor #2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-50

Feeder Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-53

Tray 2 Feed Rollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-54

Side Output Tray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-55

Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-56

Job Offset Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-56

Job Offset Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-59

Job Offset Home Position Sensor . . . . . . . . . . . . . . . . . . . . . . . 8-61

Top Output Chute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-63

Door A Latch Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-64

Media Thickness Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-66

Temperature/Humidity Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . 8-67

Exit Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-68

Exit Gate Solenoid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-70

Fuser Exit Sensor and Actuator . . . . . . . . . . . . . . . . . . . . . . . . . 8-71

Top Output Tray Stack Full Sensor. . . . . . . . . . . . . . . . . . . . . . . 8-72

xxii Phaser 7400 Color Printer Service Manual

Side Output Tray Detect Sensor . . . . . . . . . . . . . . . . . . . . . . . . . 8-73

Side Output Tray Stack Full Sensor. . . . . . . . . . . . . . . . . . . . . . . 8-75

Door E Detect Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-77

Fuser Release Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-79

Registration Sensor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . 8-80

Registration Shutter Solenoid. . . . . . . . . . . . . . . . . . . . . . . . . . . 8-81

ADC Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-82

Media Slack Sensor and Actuator. . . . . . . . . . . . . . . . . . . . . . . . 8-83

Registration Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-84

Registration Clutch #1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-85

Waste Toner Auger Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . 8-86

Waste Toner Reservoir Full Sensor. . . . . . . . . . . . . . . . . . . . . . . 8-88

Waste Toner Reservoir Auger Rotation Sensor. . . . . . . . . . . . . . 8-89

Waste Toner Auger Rotation Sensor. . . . . . . . . . . . . . . . . . . . . . 8-90

Transfer Unit Belt Rotation Sensor. . . . . . . . . . . . . . . . . . . . . . . 8-91

Lower Basket Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-92

Basket Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-93

LED Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-100

Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-103

Transfer Unit Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-103

Toner Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-104

Imaging Unit Motors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-105

Fuser Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-106

Waste Toner Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-107

Imaging Unit Lift Uplink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-108

Electrical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-111

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-111

Engine Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-112

Image Processor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-113

Card Cage Fan Duct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-114

Card Cage Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-115

Card Cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-117

HVPS Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-118

High Voltage Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-119

Housing Bias Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-120

Low Voltage Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-121

LVPS Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-124

LED Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-125

LED Relay Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-126

Top Cover Interlock Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-127

Waste Toner Reservoir Detect Switch. . . . . . . . . . . . . . . . . . . . 8-130

Door A Interlock Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-132

Imaging Unit Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-133

Transfer Unit Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-134

Top Cover Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-135

IP Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-138

Contents xxiii

Paper Size Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-139

Motor Driver Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-141

Imaging Unit Sensor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-142

Toner Supply Camshaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-144

Imaging Unit Motor Mounting Plate. . . . . . . . . . . . . . . . . . . . . 8-145

CRUM Reader Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-146

CRUM Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-147

Registration Sensor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-148

Fuser Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-149

Front Sensor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-150

Rear Sensor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-151

9 Parts List

Serial Number Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2

Using the Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

Print Engine Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4

Xerox Supplies and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-58

Service Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-60

Feed Roller Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-60

Sensor Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-61

Actuator Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-61

Screw Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-62

Hardware Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-62

Gear Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-63

Harness Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-64

10 Wiring Diagrams

Plug/Jack Locator Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2

Print Engine Plug/Jack Designators. . . . . . . . . . . . . . . . . . . . . . 10-2

Print Engine Plug/Jack Locators . . . . . . . . . . . . . . . . . . . . . . . . 10-4

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-17

Notations Used in Wiring Diagrams. . . . . . . . . . . . . . . . . . . . . 10-17

Print Engine Wiring Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-19

Print Engine General Wiring (1/7) . . . . . . . . . . . . . . . . . . . . . . 10-19

Print Engine General Wiring (2/7) . . . . . . . . . . . . . . . . . . . . . . 10-20

Print Engine General Wiring (3/7) . . . . . . . . . . . . . . . . . . . . . . 10-21

Print Engine General Wiring (4/7) . . . . . . . . . . . . . . . . . . . . . . 10-22

Print Engine General Wiring (5/7) . . . . . . . . . . . . . . . . . . . . . . 10-23

Print Engine General Wiring (6/7) . . . . . . . . . . . . . . . . . . . . . . 10-24

Print Engine General Wiring (7/7) . . . . . . . . . . . . . . . . . . . . . . 10-25

Front Sensor Board (1/2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-26

Front Sensor Board (2/2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-27

Feeder Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-28

Rear Sensor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-29

Registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-30

xxiv Phaser 7400 Color Printer Service Manual

Motor Driver Board (1/6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-31

Motor Driver Board (2/6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-32

Motor Driver Board (3/6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-33

Motor Driver Board (4/6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-34

Motor Driver Board (5/6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-35

Motor Driver Board (6/6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-36

LED Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-37

Xerographics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-38

LVPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-39

Fuser. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-40

Imaging Unit Sensor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-41

Image Processor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-42

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-43

Reference

Phaser 7400 Menu Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Printer Status Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Service Diagnostics Menu Map (1/2). . . . . . . . . . . . . . . . . . . . . . . . . . . A-11

Service Diagnostics Menu Map (2/2). . . . . . . . . . . . . . . . . . . . . . . . . . . A-12

Service Diagnostics Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-13

Mode Select Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-28

Obtaining Serial Back Channel Traces . . . . . . . . . . . . . . . . . . . . . . . . . . A-29

Preparing the Printer for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-30

Index

Contents xxv

General Information

In this chapter...

■ Printer Introduction and Overview

■ Printer Configurations

■ Parts of the Printer

■ Printer Options

■ Specifications

Section

Printer Introduction and Overview

The Xerox Phaser 7400 Color Printer Service Manual is the primary document used to repair, maintain, and troubleshoot this printer. For manual updates, Service Bulletins, knowledge base, etc., see technical support, contact your assigned Xerox Technical Support for this product.

www.xerox.com/office/7400support. For further

s7400-301

The Xerox Phaser 7400 Color Printer is a single pass, electrophotographic design, using light emitting diodes (LED) for image exposure. The Phaser 7400 supports PostScript 3 and PCL5c page description languages. Print performance for A4 paper is 40 pages per minute (ppm) monochrome, 36 ppm for full color in 1-sided or 2-sided modes. Full color prints are produced via consecutively transferring the subtractive primaries (cyan, magenta, yellow, and black) directly to paper. Resolutions of up to 600 x 1200 dots per inch (dpi), 32-level grayscale print is applicable at 600x600 dpi. The base configuration (Phaser 7400N) features USB 2.0 and 10/100baseT Ethernet Ports, 256 MB of memory, a 250-sheet multi-purpose Tray

1 (MPT), a 550-sheet input tray (Tray 2), a 500-sheet facedown Top Output

Tray, and a 250-sheet faceup Side Output Tray. Phaser 7400 printer options add memory, paper capacity and functionality. For

configurations not originally equipped, an internal Hard Drive is available for font storage, storing print files, job collation, proof, personal, and secure print support. A selection of RAM memory upgrades are available to raise the installed quantity to the 1 GB maximum. A 1650-Sheet High-Capacity Feeder (HCF) is available with three, 550-sheet universal trays. A 550-Sheet Feeder (Tray 3) Lower Tray Assembly (LTA) is also available. On the output side, a 1000-Sheet Finisher provides punching, stapling, saddle stitch, and offset stacking raising the output total to 1750 sheets. A Duplex Unit is available to add automatic 2-sided printing for supported paper sizes from all trays.

1-2 Phaser 7400 Color Printer Service Manual

Printer Configurations

The Phaser 7400 Color Printer is available in five configurations. The main differences are standard memory, optional high-capacity feeders, duplexing (2-sided printing) capabilities, networking, and internal Hard Drive. The following table lists the available configurations.

Printer Configuration

Features

7400N 7400DN 7400DT 7400DX 7400DXF

Max Print Speed (ppm) color / monochrome

Hard Drive for Secure, Proof, Personal, and Saved Print Jobs

Standard Memory* 256 MB 256 MB 512 MB 512 MB 512 MB

USB Port Ye s Ye s Yes Ye s Ye s

10/100 Ethernet Port Ye s Ye s Yes Ye s Ye s

RAM Collation Ye s Ye s Ye s Ye s Ye s

Duplex Unit Optional Ye s Ye s Ye s Ye s

PostScript / PCL Fonts Yes Ye s Ye s Ye s Ye s

Banner Sizes Ye s Ye s Yes Ye s Ye s

Photo Modes Ye s Ye s Ye s Ye s Ye s

Resolutions (dpi):

Standard Enhanced Photo

Tray 1 (MPT)** Ye s Ye s Ye s Ye s Ye s

Optional Trays ** Optional Optional 1 x 550 3 x 550 4 x 550

550-Sheet Feeder** Optional Optional Ye s Optional Ye s

1650-Sheet Feeder** Optional Optional Optional Ye s Ye s

1000-Sheet Finisher*** Optional Optional Optional Optional Ye s

* All configurations have two memory slots supporting 256 MB and 512 MB cards, up

to a maximum of 1 GB.

** Trays 1 and 2 are standard on all configurations. All configurations support

additional paper trays in the following combinations: One 550-Sheet Feeder (Tray 3) One 1650-Sheet Feeder (Trays 3, 4, and 5 or 4,5, and 6) One 550-Sheet Feeder (Tray 3) and one 1650-Sheet Feeder (Trays 4, 5, and 6) *** Requires a Hard Drive and a total of 4 optional trays for fitment.

36/40 36/40 36/40 36/40 36/40

Optional Optional Yes Ye s Ye s

600x600x1 1200x600x1 600x600x5

General Information 1-3

Metered Printing

Metered printing (PagePack), involves the combination of control software and specialized Toner Cartridges to meter printer activity for billing purposes. The Configuration page lists Metered Toner as Enabled when metering is enabled.

Metered Operation

When a metered printer is initialized at first power-up, the customer sets the printer to Metered operation using a unique, factory-supplied, 4-digit PIN. Once set to Metered operation, the control software performs the following:

1. The Mode and PIN-entered values in Engine Control Board NVRAM are set.

2. The Control Panel momentarily displays “Metered Toner is now enabled”, then

returns to “Ready” (if no other errors).

3. The First Time Tips pages and the Configuration page are printed.

If an incorrect PIN is entered, “Incorrect numeric password” displays with a prompt “Retry” or “Do not retry.” Retry returns to the enter prompt, “Do not retry” returns to the Replace [C][M][Y][K] Toner Cartridge error message. The error persists until the correct PIN is entered.

Note

The Hidden Service menu provides an Enable Metered Toner option to restore the Metered mode parameters to NVRAM should they become lost or corrupt.

Metered Toner Cartridges

To support metered printing, metered Toner Cartridges are available in all four colors. When a metered Toner Cartridge is installed in a printer not set to Metered operation, the printer displays the Replace [C][M][Y][K] Toner Cartridge error. If a metered Toner Cartridge is placed into a printer manufactured before metering was available, the printer displays Replace Incorrect Toner Cartridge. All other combinations of normal or metered printer and cartridges are accepted without warning or error.

Diagnostics Mode

Service Diagnostics does not provide the utilities to set or clear Metered NVRAM values. Service Diagnostics does not check these values and does not display the current status of these values. However, the Configuration page does identify the printer setting as mentioned above.

Note

When replacing the Engine Control Board from a metered printer, exchange NVRAM devices or use the Save/Restore utilities in Service Diagnostics to preserve the NVRAM settings. The Mode and PIN-entered values are not affected by NVRAM reset utilities.

1-4 Phaser 7400 Color Printer Service Manual

Parts of the Printer

Front View

1. Top Cover latch 6. Paper Catcher

2. Control Panel 7. Top Output Tray

3. Tray 2 8. Door A

4. Front Door 9. Tray 1 (MPT)

5. Level Indicator 10.Door B

7400-001

General Information 1-5

Rear View

9 8

6 7

7400-002

1. AC Receptacle 6. USB Port

2. Door D 7. Ethernet Port

3. Door E 8. Serial Debug Port

4. Side Output Tray 9. Mode Select Port

5. Power Switch 10.Rear Cover

1-6 Phaser 7400 Color Printer Service Manual

Control Panel

The Control Panel contains one tricolor LED, a display window, and six function buttons. These buttons navigate the menu system shown on the display, perform various functions, and select operational modes for the printer.

LED Indicators:

LED State Printer State

Green Ready to Print

Flashing Yellow Warning (but can still print)

Flashing Green In Power Saver mode or busy (receiving or processing data)

Flashing Red Error; cannot print

Control Panel Button Descriptions

Up Arrow Button

OK Button

Status Indicator LED

Cancel Button

Help (?) Button

Graphic Display

Back Button

Down Arrow Button

s7400-304

Control Panel Shortcuts

Action Press this at Power On

Skip Execution of POST Diagnostics OK

Print Service Diagnostics Menu Map Help (?)

Reset PostScript NVRAM Back + OK

Password Bypass Up Arrow + Down Arrow

Enter Service Diagnostics Back + Help (?)

General Information 1-7

Image Processor Board

Transfer the following components, if installed, to the new board when replacing the Image Processor Board.

Configuration Card

NVRAM

Hard Drive

Memory (RAM)

s7400-352

1-8 Phaser 7400 Color Printer Service Manual

Printer Options

Phaser 7400 Color Printer options include:

■ 20 GB Hard Drive

■ Additional Memory

■ 550-Sheet Feeder (LTA)

■ 1650-Sheet Feeder (HCF)

■ Duplex Unit

■ 1,000-Sheet Finisher (with hole punch, staple, saddle-stitch, and offset)

Hard Drive

A 20 GB Hard Drive is available to enable the Job Collation, Saved Jobs, Proof, Personal, and Secure Print options. The Hard Drive installs on the Image Processor Board with stand-offs and connects to the board with a single data/power connector. Hard Drive utilization appears on the Configuration page.

Additional Memory

The printer features two slots that accept 256 or 512 MB of high-speed DDR RAM. All combinations are allowed for 256, 512, 768 MB, up to the maximum of 1 GB. Memory modules must have the following characteristics:

■ DDR PC2700 Memory Standard

■ 200-Pin SODIMM

■ Unbuffered, Non-parity

■ Serial Presence Detect

■ 2.5 Volt

■ CL 2.5

s7400-004

The Startup and Configuration pages list the amount of RAM installed in the printer. Installed memory not meeting the above specifications, is ignored by the printer.

General Information 1-9

Configuration Card

A Configuration Card identifies the printer configuration, stores shadowed nonCRUM consumable data, consumable life counts, and network configuration parameters.

550-Sheet Feeder

The 550-Sheet Feeder increases the input capacity of the printer. The Lower Tray Assembly (LTA) attaches below Tray 2. When used in combination with the 1650-Sheet Feeder, the 550-Sheet Feeder is installed between the printer and 1650Sheet Feeder. Up to four optional 550-Sheet Feeders per printer, totaling six universal trays (Trays 2~6), are allowed. However, when the 1650-Sheet Feeder High-Capacity Feeder (HCF) is installed, only one additional 550-Sheet Feeder is allowed between the HCF and printer. Electrical connection to the printer is made by a single interface connector.

s7400-001

1650-Sheet Feeder

The 1650-Sheet Feeder adds three 550-sheet trays. Control signals reach the sheet feeder by a single connection.

s7400-003

1-10 Phaser 7400 Color Printer Service Manual

Duplex Unit

The Duplex Unit adds two-sided printing. The Duplex Unit is inserted into the printer’s left side just below the Side Output Tray. Electrical connection is made by an interface connector located inside the Duplex Unit cavity.

s7400-305

Finisher

The Finisher increases the output capacity of the printer by 1,000 sheets. Printer output is directed to the Finisher by way of the side exit. Depending on the job specifications, as paper enters the Finisher it can be punched, stapled, offset and stacked depending on customer driver selections or Control Panel settings. The Finisher’s Inverter is used to flip the media over. Control signals reach the Finisher through a single connector.

Finisher

Inverter

s7400-306

General Information 1-11

Maintenance Items

A maintenance item is a printer part or assembly that has a limited life, and requires periodic replacement.

Fuser

Imaging Unit

Transfer Belt

Waste Toner Reservoir

Consumables

Consumables consist of the four toner cartridges used in the printer.

Toner Cartridge

s7400-307

s7400-308

1-12 Phaser 7400 Color Printer Service Manual

Specifications

Memory Specifications

Characteristic Specification

Minimum RAM 256 MB

Maximum RAM 1 GB

Supported RAM SODIMM 200-pin module of 256 or 512 MB. All combinations are allowed

NVRAM Single chip of either PPROM or StrataFlash 16 MB

Consumable Life Specifications

Internal counters track Consumables and Maintenance Items life usage. The Image Processor Board monitors these counters in order to display the near end-of-life and end-of-use messages.

Life ratings are based on A-size sheets at 5% coverage. Imaging Unit life ratings are based on average 3 page job length.

Toner Cartridges Print Life

for configurations of 256, 512, 768 MB, and 1 GB.

Black-Capacity Color Capacity Metered (PagePack) Capacity (all colors)

Maintenance Items

Imaging Unit 30,000

Fuser 100,000

Transfer Unit 100,000

Feed Roller Kit 100,000

Waste Toner Reservoir up to 30,000

15,000 7,500 or 15,000 15,000

General Information 1-13

Electrical Specifications

Characteristic Specification

Primary line voltages

Primary line voltage frequency range

Power consumption at rated voltage input

110-127 V Printer - (90 - 135 V) 13 amp circuit 220-240 V Printer - (198 - 254 V) 7-8 amp circuit

100-120 V Printer - 50/60 Hz + 2 Hz 220-240 V Printer - 50/60 Hz + 2 Hz

Mode Print Mode Ready Mode Sleep Mode

Condition Maximum Fuser On Fuser Off

NOTE: Power the printer directly

100/120 VAC

1500 W or less 750 W or less 55 W or less

Physical Dimensions and Clearances

Print Engine Value

Height:

Width: 64.0 cm (25.2 in.) Depth:

Weight: 84 kg (185 lb.)

1650-Sheet Feeder Value

Height: 40.1 cm (15.8 in.) Width: 59.7 cm (23.5 in.) Depth: 59.9 cm (23.6 in.) Weight: 53 kg (117 lb.)

550-Sheet Feeder Value

Height: 10.9 cm (4.3 in.) Width: 59.7 cm (23.5 in.) Depth: 59.9 cm (23.6 in.) Weight: 16 kg (36 lb.)

Finisher Value

Height: 101.6 cm (40.0 in.) Width: 81.3 cm (32.0 in.) Depth: 59.5 cm (23.6 in.) Weight: 55 kg (122 lb.)

Surface Value

Tilt tolerance: Within 50 mm side to side.

47.1 cm (18.5 in.)

62.3 cm (24.5 in.)

from the wall outlet. Do not use “Power Strips” as they may limit available current.

220/240 VAC

1500 W or less 750 W or less 55 W or less

1-14 Phaser 7400 Color Printer Service Manual

Minimum Clearances

61.0 cm (24 in.)

50.8 cm (20 in.)

167.4 cm (66 in.)

68.5 cm (27 in.)

50.8 cm (20 in.)

15.2 cm (6 in.)

127.5 cm (50 in.)

61.0 cm (24 in.)

15.2 cm (6 in.)

266.4 cm (104.9 in.)

50.8 cm (20 in.)

127.5 cm (50 in.)

s7400-309

General Information 1-15

Functional Specifications

Characteristic Specification

Printing Process Imaging System: 4-tandem drums, electro-photographic system.

Exposure System: Light-emitting Diode (LED), 4 beams. Development System: Dry type 2-component developer. Fusing System: Heat fusing, free nip-belt system.

Color Medium Yellow, Magenta, Cyan, and Black Toner Cartridges

Resolution / Addressability

Operating Modes Print Mode: Print Engine capable of making prints immediately.

Maximum Color Coverage

Warm-up Time < 85 seconds from cold start (power off condition)

Standard Enhanced Photo

Ready Mode: 10 seconds from completion of a print. Sleep / Power Saver Mode: Entered after a specified period of Print Engine

inactivity since completion of the last print.

All configurations are 240%

< 75 seconds from (Wake-up)

600 x 600 dpi (default) 1200 x 600 dpi 600 x 600 (5-bit) dpi

First Print Output Time

First Print Output Time (FPOT) is defined as a time from receipt of the print command in Ready mode until the first page sourced from either Tray 1 or Tray 2 is delivered to the Output Tray. Sourcing media from the optional trays increases FPOT.

Note

This does not include the execution times for the Boot Loader or POST which vary depending on printer configuration.

Print Mode

Tray 1 (M P T) Tray 2 Tra y 3 Tray 4 Tr ay 5 Tr a y 6

Monochrome 12.0 13.5 14 15 16

Color 13 15.5 16.5 17.5 18.5

First Print Out Time* (maximum seconds)

*These conditions apply to the values in the table above: Printer at Ready A4 LEF paper Plain paper mode

1-16 Phaser 7400 Color Printer Service Manual

Image Specifications

Characteristic Specification

Maximum Print Area

Guaranteed Print Area

Skew < 1.0 mm across 220 mm image, < 1.5 mm from option trays

Registration

Leading Edge Side Edge Duplex (front to back)

Parallelism ± 0.5 mm across 220 mm image

Linearity

Ver tic al Horizontal Slant

Minimum margins = 5 mm (0.2 in.) on all sides Maximum paper size = 328 mm x 1200 mm (12.9 in.x 47.25 in.) Minimum paper size = 105 mm x 148 mm (4.13 in. x 5.83 in.)

The printer prints images meeting the Print Quality Specification except the margin area, which is 5.0 mm inside each edge of the paper.

± 1.0 mm ± 1.0 mm ±1.5 mm (A size), 2.2 mm (B size)

± 0.5 mm across 234 mm image ± 0.5 mm across 190 mm image ± 1.2 mm across 269 mm image

Environmental Specifications

Characteristic Specification

Temperature

Operating Storage Transport

Humidity (RH)

Operating Storage Transport

Altitude

Operating Non-operating

Acoustic Noise (db)

Standby Power Saver Printing

10 to 32oC (50 to 89.6 oF) 0 to 43oC (32 to 109.4 oF)

-10 to 43oC (-14 to 109.4 oF)

Relative Humidity (50 - 70% to assure the best print-quality) 20 - 80% 10 - 90% 10 - 90%

0 to 2500 meters (8,000 ft.) at 25oC 0 to 6000 meters (20,000 ft.)

45.0db or less

43.0db or less

55.0db or less

General Information 1-17

Media and Tray Specifications

The following table lists the paper sizes and weights supported in the printer trays.

Media and Tray Specifications

Specification Trays

Supported Media Sizes

Supported Envelopes*

Special Media

Tr ay Capacity

Paper Type

Letter Legal Executive Statement US Folio A4 A5 A6 B5 JIS ISO B5 Custom Size & Banner

Envelopes Weight Commercial #10 Monarch Envelope A7 Envelope Custom DL Envelope C5 Envelope C6 Envelope B5 Envelope Custom

NOTE: Do not use envelopes with hot melt glue, windows, or

metal clasps.

Phaser 35-Series Premium Transparencies

Letter A4

(Other sizes through Tray 1 using custom size option.) Phaser Premium Postcards

Standard Paper Transparency Envelopes

Letter A4

Size

8.5 x 11 in.

8.5 x 14 in.

7.25 x 10.5 in.

5.5 x 8.5 in.

8.5 x 13 in. 210 x 297 mm 148 x 210 mm 105 x 148 mm 182 x 257 mm 176 x 250 mm

8.5 x 35.4 in. 20 - 24 lb. Bond

4.12 x 9.5 in.

3.87 x 7.5 in.

5.25 x 7.25 in 110 x 220 mm 162 x 229 mm 114 x 162 mm 175 x 250 mm

216 x 279 mm (8.5 x 11 in.) 210 x 297 mm (8.27 x 11.69 in.)

Universal Tray

550 Sheets 100 Sheets N/A

All Trays All Trays All Trays All trays All Trays All Trays All Trays Tray 1 Only All Trays Tray 1 Only Tray 1 + 2

Tray 1 Only

Tray 1 + 2 Tray 1 + 2

Tray 1 Only Tray 1 Only

Tray 1 ( M P T )

100 Sheets 50 Sheets 10 each

1-18 Phaser 7400 Color Printer Service Manual

Media and Tray Specifications

Specification Trays

Supported Media Types and Weights

Typ e

Plain Paper Heavy Plain Paper Thin Card Stock Thick Card Stock

Labels Letterhead

Glossy Paper Digital Photo Paper Phaser Premium Post-

cards Pre-printed

Pre-punched Special

Weight

65 - 90 g/m2 (17 - 24 lb. Bond) 85 - 120 g/m2 (22 - 32 lb. Bond) 100 - 163 g/m2 (30 - 60 lb. Cover) 160 - 216 g/m2 (59 - 80 lb. Cover)

N/A 85 - 120 g/m2 (22 - 32 lb. Bond) 100 - 163 g/m2 (81 - 110 lb. Text) 163 g/m2 (60 lb. Cover) 176 g/m2 (65 lb. Cover)

65 - 90 g/m2 (17 - 24 lb. Bond) 65 - 90 g/m2(17 - 24 lb. Bond) 100 - 163 g/m2 (30 - 60 lb. Cover

All Trays All Trays All Trays

All Trays Tray 1 Only

All Trays Tray 1 Only Tray 1 Only Tray 1 Only

All Trays All Trays

All Trays

*Some wrinkling and embossing may occur when printing envelopes.

Note

For duplex configured printers, auto-duplex operation is available through all trays. Refer to the Paper Tips page for information on which paper types can be used for 2-sided printing.

For more details about supported paper and other media, print the Paper Tips page:

1. On the Control Panel, select Information, and then press the OK button.

2. Select Information Pages, and then press the OK button.

3. Select Paper Tips, and then press the OK button to print.

General Information 1-19

Theory of Operation

In this chapter...

■ Overview

■ Printer Controls

■ Paper Path of the Printer

■ Major Assemblies and Functions

Section

Phaser 7400 Operational Overview

The Phaser 7400 Color Printer is a full-color LED printer using electrophotographic recording principals to place a full color image onto the print media. The system, as it appears in the following illustration, contains four Imaging Units comprised of a drum and developing unit for each color Cyan, Magenta, Yellow and Black (CMYK), and uses a Transfer Unit to transfer the toner image of each color onto print media producing full-color prints.

The figure below illustrates the relative position of components involved in the printing process.

Toner Cartridge

Fuser

Transfer Unit

LED Head

Imaging Unit

s7400-384

2-2 Phaser 7400 Color Printer Service Manual

Imaging Unit

The function of each Imaging Unit component is listed in the following table.

Imaging Unit Components

Component Function

Drum The Drum is an aluminum cylinder coated with a layer of photo-

conductive material that retains electrical charges on its surface until exposed to light.

Bias Charge Roller (BCR) The BCR uniformly distributes electrical charges over the drum

Developer Roller A thin layer of developer and toner adheres to the surface of this

Sponge Roller Transfers toner to the Developer Roller. Agitation Bar The Agitation Bar stirs the developer mixture to achieve a

Cleaning Blade The Cleaning Blade removes toner remaining on the Drum. Waste Toner Recovery Moves excess toner from the Imaging Unit to the Waste Toner

Toner Cartridge Agitation Spring

surface, and erases the previous charge pattern.

roller, which transports the toner to the Drum surface.

uniform distribution of toner.

Recovery system for collection.

Shutter

Agitation Bar

Target

Charge Roller

Sponge Roller

Developer Roller

Drum

s7400-022

Theory of Operation 2-3

LED Heads

The LED Heads receive signals from the Engine Control Board and scan the surface of the four Imaging Unit drums to create a latent image. The resolution is either 600

dpi or 1200 dpi and is determined by the customer setting.

LED Head

Light Cover

LED Holders

s7400-385

Fuser

The Fuser, using a combination of heat and pressure, bonds the toner to the paper. The Fuser is replaced as a unit. The Heat Roller is heated by two internal halogen lamps, and the Pressure Roller is heated by a separate lamp. The Pressure Roller puts pressure against Fuser Belt, media, and Heat Roller to melt the toner and bond the image to the paper. After the toner image is fused to the paper, the paper passes through the Fuser Exit Sensor indicating the sheet’s progress. To better understand Fuser errors, Fuser components are described in the following table.

Fuser Components

Component Function

Heat Roller The Heat Roller is a metal tube with a coated surface and a

Heater Assembly inside. As paper passes between the Heat Roller and Pressure Roller, the heat fuses the toner to the paper.

Pressure Roller The Pressure Roller is a metal shaft coated with sponge rubber.

Heater Lamps The Heater Lamps are quartz glass tubes containing heater

The Pressure Roller maintains pressure on the paper passing between it and the Heat Roller. This pressure bonds the melted toner to the paper.

coils. The Heater Lamps heat the Heat Roller.

2-4 Phaser 7400 Color Printer Service Manual

Fuser Components (Continued)

Component Function

Temperature Sensors These are Thermistors having a known value of resistance that

Thermostats The Thermostats provide a second-level of protection. If the

Fuser Exit Sensor This sensor detects the arrival of the paper at the exit area of the

varies with temperature. The sensors monitor the surface temperature of the Heat and Pressure Rollers.

Heat or Pressure Roller temperature exceeds the target temperature, AC power is cut-off to the Heater Rods. Once the Thermostats have opened, the Fuser must be replaced.

Fuser. When paper is present, the signal /EXIT is Low.

Fuser Life Expectancy

The life expectancy is 100,000 Letter/A4 size pages. Several factors reduce Fuser life:

■ Paper use larger than letter size

■ Printing on heavy media

■ Printing short-edge feed

■ Printing on transparencies or specialty media

■ Repetitive image, long print runs

Transfer Unit

The Transfer Unit transports the media under all four Imaging Unit drums using a belt. Transfer Rollers within the Transfer Unit receive biasing voltages from the HVPS to attract the toner from the drums to the media.

Imaging Unit Drums

KY MC

Transfer Unit Belt

Transfer Rollers

Transfer Unit Belt Motor

s7400-030

Theory of Operation 2-5

Print Process Summary

The block diagram illustrates the steps involved in producing a full-color print. The (numbers) indicate the corresponding description provided in the Print Process Summary that follows this diagram.

Print Process Block Diagram

Drum C Drum M

Charged with

(1)

electricity

Exposure

(2)

Develop-

(3)

ment

(5) Fusing

(8) Exit

Top Output Tray Side Output Tray

Charged with

(1)

electricity

(2)

Exposure

Develop-

(3)

ment

(4) Transfer

Drum Y Drum K

Charged with

(1)

electricity

(2)

Exposure

Develop-

(3)

ment

(6) Transfer Unit Cleaning

(7) Imaging Unit Cleaning

(9) Waste Toner Recovery

(1)

(2)

(3)

Charged with electricity

Exposure

Development

s7400-383

Refer to the Print Process Block Diagram above to relate each of the following process steps to an individual component.

2-6 Phaser 7400 Color Printer Service Manual

1. Charging: The charge roller (RTC) is negatively charged by the High-Voltage

Power Supply (HVPS) and is kept in contact with the drum surface to provide a uniform negative charge on the drum as it rotates at a constant speed. This occurs simultaneously for CMYK.

HVPS

Drum

Charge Roller

s7400-018

2. Exposure: The Light Emitting Diode (LED) Head emits light to the negatively

charged surface of the drum. Areas of the drum surface receiving the light attenuate the negative charge based on light intensity and surface potentials, forming the latent electrostatic image on the drum surface. This occurs simultaneously for CMYK.

Charge

LED Head

Roller

HVPS

Drum

Paper

s7400-017

3. Development: The Developer Roller applies toner to the latent image formed

on the surface of the drum. Toner transfer occurs as follows:.

■ The sponge roller transfers toner to the Developer Roller. The toner is

negatively charged.

■ The toner cleaning blade removes excess toner on the Developer Roller to

form a thin film of toner on the surface of the Developer Roller.

Theory of Operation 2-7

■ The toner is attracted to the latent image on the surface of the drum at the

point where the drum is in contact with the developing roller.

Toner

Charge Roller

Cleaning Blade

Drum

Developer Roller

Sponge Roller

s7400-019

4. Transfer: The Transfer Roller, made of a conductive sponge, presses the paper

against the surface of the drum. This process sandwiches the paper between the drum and the Transfer Unit belt. A positive charge, supplied by the HVPS through contacts on the Transfer Unit, is applied to the Transfer Roller attracting the negatively-charged toner from the surface of the drum onto the paper.

Drum

Paper

Transfer Unit Belt

Transfer Roller

HVPS

s7400-020

2-8 Phaser 7400 Color Printer Service Manual

5. Fusing: The Fuser uses a combination of heat and pressure to bond the toner

image to the paper.

Thermostat

Thermistor

Paper

Heat Roller

Pressure Roller

Pat

Fuser Belt

Thermistor

Thermostat

s7400-021

6. Transfer Unit Cleaning: Toner remaining on the Transfer Unit belt is removed

by a cleaning blade and transported by Auger to the toner waste port.

Transfer Unit Belt

Direction of Belt Rotation

Cleaning Blade

Auger

Toner Waste Port

s7400-023

7. Imaging Unit Cleaning: Toner remaining on the drum, following image

transfer to the media, is scraped off by a cleaning blade and collected.

8. Paper Exit: The paper is then advanced either upward to the Top Exit or

downward towards the Side Exit depending on the Exit Gate position.

9. Waste Toner Recovery: Excess toner collected from the Imaging Unit drums

and the Transfer Unit belt is carried by an Auger Tube to the Waste Toner Reservoir located behind the Front Door.

Theory of Operation 2-9

Printer Controls

Print-Quality Modes

There are four print-quality modes:

Print-Quality Mode Description

Automatic Automatically selects the optimal print-quality mode for the paper

Standard 600 X 600 dpi resolution. High-speed, general-purpose mode for

Enhanced

Photo

type. For example, Photo print-quality mode is used when printing on Glossy Paper and Standard print-quality mode is used when printing on Plain Paper. (This setting is only available in the printer driver.)

crisp, bright, color prints. Recommended for most office use and quick prints.

600 X 1200 dpi resolution. High-quality mode for fine lines and detail. Recommended for vibrant, saturated, color prints. Balances printing speed with quality.

600 X 600 dpi resolution. Highest-quality mode for color prints and smoothest light colors. Recommended for photographs, smooth shaded drawings, and color.

Color Registration Control

The printer uses a single-pass, quad system where each color (Yellow, Magenta, Cyan, and Black) has its own imaging drum. Images are formed on the drums, in the respective colors, and then layered on the media to form one image. To monitor color registration, photo-reflective, Color Registration Sensors are mounted inside the Registration Sensor Assembly. These sensors are positioned at the front and rear edges of the Transfer Unit belt as shown in the following figure.

2-10 Phaser 7400 Color Printer Service Manual

Imaging Unit

Drum

Transfer Unit Belt

LED Head

Belt Running Direction

Color Registration Sensor

Cleaning Blade

Transfer Belt

Cleaning Blade

Color Registration Front Sensor

Belt Running Direction

Color Registration Rear Sensor

(Transfer Unit as seen from below)

s7400-041

The Color Registration Sensors are used to measure the amount of misalignment based on the position of the color patches in relation to the black toner patch that precedes them. According to this measurement, the printer determines the correct value and automatically adjusts color registration in the main scanning, sub-scanning, and diagonal directions.

Theory of Operation 2-11

To avoid a positional shift between the different color images, the color registration control generates an alignment pattern (a series of primary color toner patches on either side of the Transfer Unit belt.

Color Registration Sensor Front

Color or Check Pattern

Color Registration Sensor Rear

s7400-623

Color registration control is outlined below:

1. With no toner on the Transfer Unit, the output value of the Color Registration

Sensors is measured to determine the reference value.

2. Patches for color registration control are generated on the edges of the Transfer

Unit belt.

3. A solenoid-activated Registration Shutter opens so the sensors are exposed to the

toner patches on the Transfer Unit belt.

4. The position of the patches generated is measured by the Color Registration

Sensors.

5. The amount of registration shift is calculated from the reference value

determined in Step 1, and the patch alignment measured in Step 4.

6. The image write timing is changed to compensate for any registration shift.

Color registration is checked when the power is turned On, a cover is closed, the printer is idle for more than 2 hours, or after printing 400 sheets.

2-12 Phaser 7400 Color Printer Service Manual

Automatic Density Control

The printer uses a series of test patches printed down the center of the Transfer Unit belt to monitor the density of toner being supplied to the Imaging Unit drums. The test patches consist of a grouping of all four colors applied repeatedly to the Transfer Unit belt at density levels of 15, 30 50, 70, 85, and 100%. During the adjustment cycle, these patches are printed twice and the ADC Sensor voltage outputs are stored as reference values. During the status cycle, the test patches are generated once and the resulting ADC Sensor voltages are compared to the reference values obtained during the adjust cycle. Differences in the adjust and status ADC Sensor values indicate how much to adjust the amount of toner being dispensed for each color.

The following diagram depicts the Transfer Unit belt with the test patches.

Transfer Unit

x2 Times

Duty 100%

Duty 70%

Duty 30%

ADC Sensor

Transfer Unit

ADC Sensor

Duty 100%

Duty 85% Duty 70% Duty 50%

Duty 30%

Duty 15%

s7400-624

Selective Control: Paper Pick

Unless changed in printer setup, the default tray is Tray 2. Trays in the optional 1650-Sheet Feeder are identified as Trays 3, 4, and 5. The tray in the optional 550-Sheet Feeder is identified as Tray 3. If both optional feeders are installed, the 550-Sheet Feeder tray is identified as Tray 3, and the trays of the 1650-Sheet Feeder are identified as Trays 4, 5, and 6.

Note

The Phaser 7400 printer supports a maximum of 4 optional trays.

Theory of Operation 2-13

Image Transfer Control

The printer monitors environmental conditions with the temperature and humidity sensors. The printer computes the optimal transfer voltage under the current environmental conditions (temperature and relative humidity), and applies the optimal transfer voltage to the Imaging Units and Transfer Unit Rollers.

Fuser Temperature Control

During Fuser temperature control the printer’s target temperature is set based on the media weight reported by the Media Thickness Sensor. The target temperature is also changed according to the printer’s internal temperature and humidity detected with the Temperature and Humidity Sensor, print count, print mode, media type, and input power supply voltage. Different target temperatures are set for standby, printing, and process control.The Heat Roller surface temperature is controlled to match the target temperature by turning the heater rods On and Off.

Fuser temperature is regulated according to the sum of the temperatures detected at the Heat Roller and Pressure Roller surfaces. There is also a thermostat for safety purposes. When the Heat Roller temperature rises above a certain temperature, the thermostat opens and shuts down the power supplied to the heater rods.

Consumable Control

The new/in-use condition of maintenance units is determined by the condition of a fuse. If the fuse in either the Fuser, Imaging Unit, or Transfer Unit is intact, the unit is recognized as a new. This fuse is checked when the printer is turned On, or a cover has been opened. When a new unit is detected, the printer resets the unit’s life counter and blows the fuse indicating the unit is in-use. The count will not indicate it has been reset until two pages have been printed.

Consumable Life Counter Behavior

Internal counters track consumable life usage and store the values on the Engine Control Board EEPROM. The Image Processor Board stores the pixel count information in NVRAM and monitors these counters in order to display the consumable near end-of-life and at end-of-life messages.

The toner states displayed are OK, Low, and Empty. When an empty state is reached, the printer terminates printing at the end of the current page and displays the appropriate message on the Control Panel. No further jobs are accepted. All printer CRCs wait for the current print job to finish before declaring a Low or Empty state.

2-14 Phaser 7400 Color Printer Service Manual

Sensors

The printer contains sensors of various types that perform a variety of functions. One group of sensors track the progress of the paper along the paper path, and detect if a paper jam occurs. Other sensors detect the presence of the Toner Cartridges, stop printer activity if a door is open (interlock), detect the presence and size of media in the trays, and monitor the fusing temperature.

Sensor Types

The types of sensors used vary with function. In general, there are four types in use:

Photo Sensors

Two types of photo sensors are used, photo-reflective and photo-receptive. Photo-reflective sensors use light reflected back from an object to detect its presence. Photo-receptive sensors use an actuator or the object itself to block the light path to detect an object or condition.

Photo-reflective sensors have the light emitter and light receiver aligned on a single surface. Output of the photo-receptor is High (> +4.5 V) when light is being reflected back and Low (< +.3 V) when it isn’t. Photo-receptive sensors consist of a LED in one arm of a U-shaped holder, and a photo-transistor in the other arm. When the sensing area is unobstructed, light falls on the photo-receptor sending the signal High. If the light is interrupted, the photo-transistor goes Low. The figure below shows a typical photo-receptive sensor with the Hooks (catches) used to secure the sensor to its bracket.

Hooks

Hook

Sensor Bracket

s7400-310

Theory of Operation 2-15

Microswitches

Microswitches are used primarily as paper size sensors and cover or door interlocks. They are in a normally open state, and close when actuated. A bank of microswitches is used to detect paper size in the universal trays.

Thermistors

Thermistors have a known value of resistance at a certain temperature. Used primarily in the Fuser for temperature sensing.

Hall-Effect

Hall-Effect sensors detect the magnetic properties of the actuator. Hall-Effect sensors are used to monitor activity of the Waste Toner Recovery system and Transfer Unit belt. Use a magnetic source to actuate these sensors during testing.

List of Sensor and Interlock Types

Name Type Function

Level Sensor Photo-receptive Detects paper stack height in Trays 2~6.

No Paper Photo-receptive Detects no paper condition in all trays.

Paper Size Microswitch array Detects the tray and the paper size.

Registration Photo-receptive Detects paper at the registration rollers.

Color Registration Photo-reflective Monitors color registration.

Feed-Out Photo-receptive Detects paper leaving the feeder.

Fuser Exit Photo-receptive Detects paper as it leaves the Fuser.

Stack Full Photo-receptive Detects when the output tray is full.

Temperature Thermistor Monitor Fuser roller temperatures.

Door Interlocks Microswitch Interrupts +24 V to the Motors.

Low Toner photo-reflective Detects toner in the Imaging Units.

Fuser Thermostats Thermostatic switches Interrupts AC power to the Fuser.

Offset Home Photo-receptive Detects Offset carriage position.

Temp/Humidity Integrated circuit Monitors the printer’s environment.

Waste Toner Hall-effect Monitors waste augers and transfer belt.

CRUM antenna RFID code reader Communicates with the CRUMs.

2-16 Phaser 7400 Color Printer Service Manual

Sensors in the Printer

The following illustrations identifies the location of each sensor.

Color Registration Sensors

Waste Toner Reservoir Auger Rotation Sensor

Waste Toner Reservoir Full Sensor

Transfer Unit Belt Rotation Sensor

Fuser Exit Sensor

Media Slack Sensor

Door E Detect Sensor

Toner Supply CM Sensor

Low Toner Sensors

Drum Phase Sensors

ADC Sensor

Temperature/Humidity Sensor

Toner Supply YK Sensor

Imaging Unit Up/Down Sensor

Waste Toner Auger Rotation Sensor

s7400-586

Door A Interlock Switch

Fuser Release Sensor

CRUM Antennae

Top Cover Interlock Switch

Waste Toner Reservoir Detect Switch

MPT Home Position Sensor

Door B Detect Sensor

Media Thickness Sensor

Theory of Operation 2-17

The diagram below identifies the paper feed sensors.

Job Offset Trailing Edge Sensor

Side Output Tray Stack Full Sensor

Job Offset Home Position Sensor

Paper Size Switch

Top Output Tray Stack Full Sensor

Side Output Tray Detect Sensor

Feed Out #1 Sensor

Transfer Unit Entrance Sensor

Registration Sensor #1

MPT Level Sensor

OHP Sensor

Feed Out Sensor #2

MPT No Paper Sensor

Tray 2 Level Sensor

No Paper Sensor #2

Registration Sensor #2

Tray 2 Low Paper Sensor

s7400-58

2-18 Phaser 7400 Color Printer Service Manual

Sensor Functions

The following table lists the function of each sensor.

Sensor Functions

Sensor Function Sensor State

Top Output Tray Stack Full Sensor

Side Output Tray Stack Full Sensor

Side Output Tray Detect Sensor

Job Offset Home Position Sensor

Job Offset Trailing Edge Sensor

Top Cover Interlock Detects the position of the Top Cover. On: open

Door A Interlock Detects the position of Door A. On: open

Door B Detect Detects the position of Door B. On: open

Door C Detect Detects the position of Door C for Trays 3 ~ 6. On: open

Door D Detect Detects the position of Door D. On: open

Door E Detect Detects the position of Door E. On: open

Waste Toner Reservoir Detect Switch

Fuser Exit Sensor Detects media at the Fuser Exit. On: media present

Fuser Temperature Monitors the Fuser process temperature. Reference voltage Media Slack Sensor Detects media slack at the Fuser entrance. On: slack

Media Thickness Sensor

Temperature/ Humidity Sensor

Tray 1 (MPT) FeedOut Sensor #1

Tray 1 ( M PT ) N o Paper Sensor

Tray 1 (MPT) Level Sensor

Detects the Top Output Tray stack height. On: not full

Off: full

Detects the Side Output Tray stack height. On: not full

Off: full

Detects whether the Side Output Tray is open or closed.

Detects the position of the Job Offset carriage. On: not home

Detects the trailing edge of the media for the Offset carriage.

Detects the presence of the Waste Toner Reservoir. On: present

Adjusts print parameters according to media thickness.

Measures environmental conditions to calculate the optimal transfer voltage.

Detects media leaving the Feed Rollers. On: media present

Detects the absence of media in the tray. On: media present

Detects the Tray 1 (MPT) media supply. On: media present

On: open Off: closed

Off: home On: media present

Off: media absent

Off: closed

Off: absent

Off: media absent

Off: no slack Reference voltage

Reference voltage

Off: media absent

Theory of Operation 2-19

Sensor Functions (Continued)

Sensor Function Sensor State

Tray 1 (MPT) Home Position Sensor

Transfer Unit Belt Rotation Sensor

Color Registration Sensors

Fuser Release Sensor

Waste Toner Auger Rotation

Waste Toner Reservoir Auger Rotation

Waste Toner Reservoir Full

Transfer Unit Entrance Sensor

Registration Sensor #1Detects media at Registration Roller #1. On: media present

Duplex Entrance Sensor

Duplex Reverse Sensor

Duplex Front Sensor Detects the trailing edge and exit from the Duplex

Duplex Rear Sensor Detects the leading edge following inversion. On: media present

Toner Cartridge CRUMs

Low Toner Sensors Detects full, low, and empty state of Toner

Imaging Unit Drum Phase Sensors

Lift Uplink Sensor Detects the position of the Lift Uplink On: IUs up

OHP Sensor Detects the presence of transparency media. On: opaque

Paper Size Switches Detects the size of media loaded in the universal

Feeder Registration Sensor

Feeder Level Sensor

Detects the position of the Tray 1 (MPT) Turn Clutch for pick operations.

Used to count Transfer Unit belt revolutions. Voltage pulse

Monitors color registration pattern produced during automatic color registration processing.

Detects the presence of the Fuser. On: absent

Detects Waste Toner Manifold Auger rotation. Voltage pulse

Detects Waste Toner Reservoir Auger rotation. Provides count signal for cartridge life.

Detects when the Waste Toner Reservoir is full. On: full

Detects media leaving Registration Roller #1. On: media present

Detects media entering the Duplex Unit. On: media present

Detects the trailing edge and signals the Duplex Gate Solenoid to switch position.

Unit.

Detects the type of Toner Cartridge installed. Data

Cartridges. Detect the position of the Imaging Unit drums. On: absent

trays. Detects media at the universal tray’s Registration

Roller. Detects the lift position of media in the universal

trays.

On: not home Off: home

Reference voltage

Off: present

Voltage pulse

Off: not full

Off: media absent

Off: media absent On: media present

Off: media absent

Sensor state transition timing

Off: present

Off: IUs down

Off: transparent See chart.

On: media present Off: media absent

2-20 Phaser 7400 Color Printer Service Manual

Sensor Functions (Continued)

Sensor Function Sensor State

Feeder Feed-Out Sensor

Feeder No Paper Sensor

Feeder Low Paper Sensor

Detects media leaving the universal tray’s Feed Rollers.

Detects the absence of media in the universal trays. On: media present

Detects a low condition of media loaded in the universal trays.

On: media present Off: media absent

Off: media absent On: media present

Off: media absent

Paper Level Detection

As paper is fed from the tray, the paper level drops. When the paper level reaches a certain point, an actuator unblocks the Level Sensor signaling the control logic to stop paper feed and raise the tray bottom. Raising the tray bottom pushes the paper up to achieve optimum force against the Feed Roller and blocks the Level Sensor resuming paper feed. This loop continues until the No Paper sensor is activated. Paper level sensing operates the same way for Trays 2 through 6. Tray 1 (MPT) uses No Paper sensing only.

Paper Present Detection

When the last sheet is fed from any of the trays, the No Paper Sensor actuator drops into an opening in the paper tray, unblocking the sensor. Feeding is inhibited until paper is loaded into the tray.

Transparent Media Detection

An Over Head Projector (OHP) Sensor is mounted on Door A at the Registration Assembly entrance. This sensor monitors media entering the Registration Assembly and signals when transparent media is being fed.

Automatic Media Thickness Detection

The printer uses the Media Thickness Sensor to determine the thickness of media passing through the Registration Assembly. The printer automatically adjusts the Fuser temperature, Fuser speed, and electrophotographic parameters to accommodate the detected media weight. Automatic thickness detection (ATS) is available from any media source.

Note

A special paper type is available in the Tray Paper Type menu that turns off ATS when selected. This allows manual configuration of print parameters if the automatic settings do not produce the desired result.

Theory of Operation 2-21

Paper Size Detection

Trays 2 through 6 automatically sense the standard size media loaded in the printer by using the Paper Size Switches mounted on the frame at the back of the tray opening. When paper is loaded in the tray and the paper guides are adjusted, the levers on the bottom of the trays change the Paper Size Switch Actuators.

Actuating different combinations of the Paper Size Switches produces different combinations of high and low signals. These signals identify what size of paper has been loaded and what to display on the Control Panel. Also, any actuation of the size switches signals the Engine Control Board that the tray is present and closed.

Universal Tray Paper Size Switch States

SW1 SW2 SW3 SW4 Media Size

0 0 0 0 No tray installed 1 1 1 1 A/Letter (LEF) 1 0 1 0 A/Letter (SEF) 1 0 0 1 A3 0 0 1 1 A3-Nobi 1 1 1 0 A4 (portrait) 0 0 1 0 A4 (landscape) 0 1 1 0 A5 0 1 1 1 A6 0 0 0 1 B4 1 1 0 0 B5 (LEF) 1 0 0 0 B5 (SEF) 1 0 1 1 B/Tabloid 1 1 0 1 Executive 0 1 0 0 Ledger 13 in. 0 1 0 1 Legal 14 in.

s7400-645

2-22 Phaser 7400 Color Printer Service Manual

Jam Detection

The printer checks for a paper jam when the printer is powered on and during printing. When a paper jam occurs, printing immediately stops. Below is a diagram of jam locations within the printer.

■ Media Jams occur in the paper path if the associated sensor does not turn On

within a specified amount of time, meaning the jam occurs prior to reaching the sensor, or if the sensor does not turn Off within a specified amount of time, meaning the jam occurs along the path of the sensor.

■ Misfeeds occur when the paper can not be loaded from the tray.

■ Paper size errors occur when the Registration Sensor does not turn Off within a

specified amount of time based on paper size settings in NVRAM.

Jam at Door E

Exit Sensor

Jam at

Door D

Duplex

Entrance

Sensor

Jam at Duplex Entrance

Jam at Fuser

Double Rear

Sensor

Jam under

Imaging Units

Double

Front Sensor

Jam in Duplex

Transfer Unit

Entrance Sensor

Tray 2

Tray 3

Tray 4

Tray 5

Tray 6

Registration #1 Sensor

Jam at Door A

Feed-out Sensor #1

Jam at Door B Jam at Door C Jam at Door C Jam at Door C Jam at Door C

s7400-036

Theory of Operation 2-23

Interlock Detection

If the Top Cover, Door A is opened, or the Waste Toner Reservoir is removed, an Interlock Switch is opened cutting the +24V source to the HVPS. At the same time, the CPU receives a signal indicating the Interlock Switch state, and displays the appropriate error message.

Toner Detection

Each Imaging Unit contains an Agitation Gear and Agitation Bar. The Agitation Bar moves toner delivered by the Toner Cartridge to the area above the Developer Roller. Located at one end of the Agitation Bar is the Low Toner Sensor target.

The photo-reflective, Low Toner Sensor mounted on the Imaging Unit Sensor Board detects the target at the end of the Agitation Bar and changes state in relation to light reflected back from the target. As the toner level drops, the period of time the Agitation Bar target remains at its highest point is reduced. This change in Agitation Bar timing signals toner level changes.

OFF Time (Minimum Height) ON Time (Maximum Height)

Low Toner Sensor

Agitation Bar

Target Board

s7400-173

2-24 Phaser 7400 Color Printer Service Manual

Toner Full State

When the Imaging Unit is at a toner full state, the Agitation Bar target remains at its maximum height for a period exceeding .85 seconds. Periods in excess of .85 seconds indicate a toner full state. Periods below .85 seconds indicate at toner low state.

Agitation Bar

Target

Toner Full: 100g Toner Low: 75g

s7400-039

Toner Low State

As the toner supply is depleted at the Imaging Unit Drum, the period of time the Agitation Bar remains at its lowest position increases reducing the amount of time the target remains in the sensor’s range. This period of time (<.85 sec.) is monitored to determine when a toner low condition exists.

Note

The time used to determine the amount of toner in the Imaging Unit varies with print speed. The value of .85 seconds relates to a print speed of 37 ppm.

Theory of Operation 2-25

Toner Cartridge Agitation Spring

Shutter

Agitation Bar

Target

Toner Full: 100g Toner Low: 75g

s7400-040

Toner Supply

If after checking the Low Toner Sensor three times, the state remains low, then the toner supply agitator and toner cartridge agitation spring rotate, supplying additional toner to the Imaging Unit. This continues until one cycle of toner high level is detected. At this point, the toner supply agitator and a toner cartridge agitation spring stop.

When a toner low state is detected 20 consecutive times, it indicates that the Toner Cartridge is low. Once this condition is recognized, the Toner Low warning message for the appropriate color is displayed after the printing of an equivalent of 5% coverage for 200 A sized sheets. At this point, the Toner Cartridge is considered empty.

2-26 Phaser 7400 Color Printer Service Manual

Input Paper Path

Paper is transported through the printer along the paper path shown below.

Exit Rollers

Duplex

Entrance

Duplex

Transport

Rollers

Roller

Fuser

Tray 2

Tray 3

Tray 4

Tray 5

Tray 6

Registration Roller #1

Tray 1 (MPT) Feed Roller

Registration Roller #2

Transfer Unit Belt

Feed Roller

s7400-024

Paper Fed from Tray 1 (MPT)

1. Paper loaded in the tray is detected by the Tray 1 (MPT) No Paper Sensor.

2. The Registration Motor rotates CCW (b) lifting the sheet to the pre-feed position

detected by the Tray 1 (MPT) Level Sensor.

3. The Feed Motor is shared with Tray 2. To feed media from Tray 1 (MPT), the

Feed Motor reverses direction (CCW) to drive the Pick and Feed Rollers pulling the sheet into the printer

Theory of Operation 2-27

4. The leading edge of the sheet is detected by the Feed-Out Sensor #1. Depending

on the size of the sheet, the Feed Motor continues to drive the sheet until the leading edge reaches the Registration Sensor #1 and a deskew buckle is induced to align the sheet.

5. The Registration Motor rotates CW (a) and the Registration Clutch #1 is engaged

moving the media to the Transfer Unit Entrance Sensor. The Feed Motor continues to rotate until the leading edge arrives at the Transfer Unit Entrance Sensor.

6. As each sheet passes the Feed-Out Sensor #1, the Registration Motor lifts the

next sheet to pre-feed position.

7. Following the last sheet being fed, the Level Sensor goes low, the Registration

Motor rotates in the CCW (b) direction to return the Lift Plate to a home position detected by the Tray 1 (MPT) Home Position Sensor.

Registration Sensor #1

Transfer Unit Entrance Sensor

Registration Roller #1

Registration Clutch #1

Feed-Out Sensor #1

Retard Roller

Feed Roller

Pick Roller

Level Sensor

Paper

No Paper Sensor

Transport Roller

Registration Motor

Feed Motor

s7400-171

2-28 Phaser 7400 Color Printer Service Manual

The Tray 1 (MPT) Lift Plate should remain down (home position) when opened. It should only lift when media is sensed. However, the Tray 1 (MPT) Lift Plate is spring loaded. These springs are compressed under the Lift Plate by the Lift Arms driven by the Registration Motor.

When you open Door A, the Lift Arm gear train is disengaged from the Registration Motor and the springs are free to raise the Lift Plate. This becomes important when servicing Tray 1 (MPT) as the Lift Arms can be trapped underneath the Lift Plate.

When the printer's on, closing the Tray 1 (MPT) and then reopening it returns the Lift Plate to home position. When the printer's off, to return the Lift Plate to home position, close the Tray 1 (MPT) and Door A. Next, open Door A with the Tray 1 (MPT) closed. Now, when Tray 1 (MPT) is opened, it should be back to its home position.

Components of Tray 1 (MPT) include:

■ No Paper Sensor

Detects presence or absence of print media in the tray.

■ Home Position Sensor

Detects the position of the lift arm. When the lift arm is down, the lift plate is at Home Position.

■ Level Sensor

Detects the leading edge of the media based on the position of the Actuator.

■ Registration Clutch #1

This clutch transfers Registration Motor drive to the lift arms.

■ Feed-Out Sensor #1

Detects the leading edge as the media leaves the Feed Rollers.

■ Registration Roller #1

This roller assembly aligns the leading edge of the sheet to correct any skew.

■ Registration Sensor #1

These sensors detect the presence of media as it arrives at the Registration Rollers.

■ Transfer Unit Entrance Sensor

Detects the media as it leaves the Registration Roller #1.

Theory of Operation 2-29

Paper Fed from Tray 2

1. Paper loaded in the tray is detected by the Tray 2 Paper Size Switch.

2. The Tray 2 Lift Motor rotates lifting the sheet to the pre-feed position detected by

the Tray 2 Level Sensor.

3. The Feed Motor turns (CCW) driving the Feed and Pick rollers to feed the sheet

from Tray 2.

4. The Feed-Out Sensor #2 detects the media as it leaves the Feed Rollers.

5. The Feed Motor continues to rotate until a deskew buckle is induced in the sheet

against the Registration Roller #2. Registration Sensor #2 goes High when the sheet reaches the Registration Roller #2.

6. The sheet moves towards the Transfer Unit when the Registration Clutch #2 is

engaged driving the Registration Roller #2 and Transport Rollers.

7. As the sheet reaches the Registration Roller #1, it is detected by the Registration

Sensor #1.

8. When the Registration Sensor #1 goes High, the Registration Clutch #1 is

activated to move the sheet through the Registration Roller #1 to the Transfer Unit.

9. The sheet is detected by the Transfer Unit Entrance Sensor and the Transfer Unit

Motor rotates to drive the sheet through the Imaging Units.

10. As the trailing edge of each sheet passes the Feed-Out Sensor, the Lift Motor lifts

the next sheet to pre-feed position.

2-30 Phaser 7400 Color Printer Service Manual

Registration Roller #1

Transfer Unit Entrance Sensor

Registration Sensor #1

Pick Roller

Registration

Clutch #1

Feed Roller

Registration

Clutch #2

Feed-Out

Sensor #2

Transport Rollers

Registration Roller #2

Registration Sensor #2

Paper

Feed Motor

Retard Roller

Registration Motor

s7400-026

Theory of Operation 2-31

■ No Paper Sensor

Detects presence or absence of print media in the tray based on the position of the Actuator.

■ Level Sensor

Detects presence of media in the tray based on the position of the Actuator.

■ Paper Size Switches

Detects media size using the position of the side and rear guides, and presence of the paper tray.

■ Registration Motor

This motor drives the Registration Rollers to pull media from the tray into the paper path.

■ Registration Clutch #2

This clutch transfers Tray 2 Registration Motor drive to the Registration Rollers.

■ Registration Roller #2

This roller is used to align the leading edge of the sheet to correct any skew.

■ Registration Sensor #2

This sensor detects the media as it arrives at the Registration Roller #2.

■ Feed-Out Sensor #2

This sensor detects the media as it leaves the Tray 2 Feed Rollers.

■ Feed Motor

This motor drives the Feed Rollers to pick paper from the tray and position it at the Registration Roller.

■ Lift Motor

This motor lifts the tray’s base plate raising the media to the pre-feed position.

■ Low Paper Sensor

The actuator lowers as print media is used in the tray. When the actuator lowers to a pre-determined position, it blocks the sensor to trigger a low paper status.

2-32 Phaser 7400 Color Printer Service Manual

Paper Fed from Optional Trays

The following describes the paper path as it is fed from the optional Tray 3. Trays 4 through 6 function in the same manner. Media moves along the paper path as follows:

1. Paper loaded in the tray is detected by the Paper Size Switches.

2. The tray’s Lift Motor rotates lifting the sheet to the pre-feed position detected by

the Level Sensor.

3. The Feed Motor turns (CCW) driving the Feed and Pick rollers to feed the sheet

from the tray into the Registration Roller.

4. The Feed-Out Sensor #3 detects the media as it leaves the Feed Rollers.

5. As the trailing edge of each sheet passes the Feed-Out Sensor #3, the Lift Motor

lifts the next sheet to pre-feed position.

6. The Feed Motor rotates until the leading edge is against the Registration Roller

#3 inducing a deskew buckle. Registration Sensor #3 goes High to indicate the sheet’s position.

7. The sheet moves towards the Transfer Unit when the Registration Clutch #3 is

engaged driving the Registration Roller #3 and Transport Rollers.

8. As the sheet reaches the Registration Roller #2, it is again aligned and detected

by the Registration Sensor #2.

9. When the Registration Sensor #2 goes High, the Registration Clutch #2 is

activated to move the sheet through the Registration Roller #2 to the Registration Roller #1.

10. As the sheet reaches the Registration Roller #1, it is detected by the Registration

Sensor #1.

11. When the Registration Sensor #1 goes High, the Registration Clutch #1 is

activated to move the sheet through the Registration Roller #1 to the Transfer Unit.

12. The sheet is detected by the Transfer Unit Entrance Sensor and the Transfer Unit

Motor rotates to drive the sheet under the Imaging Units.

Theory of Operation 2-33

Pick Roller

Feed Motor

Registration Clutch #2

Registration Motor

Registration Clutch #3

Feed-Out Sensor #3

Feed Roller

Registration Roller #2

Registration Sensor #2

Tray 2

Registration Roller #3

Tray 3

Registration Sensor #3

Retard Roller

Registration Motor

s7400-027

The paper supply and path for the optional trays involve these components:

■ Level Sensor

Detects presence of media in the tray based on the position of the Actuator.

■ Paper Size Switches

Detects media size using the position of the side and rear guides, and presence of the paper tray.

2-34 Phaser 7400 Color Printer Service Manual

■ Registration Motor

This motor drives the Registration Rollers to pull media from the tray into the paper path.

■ Registration Clutch

This clutch transfers Registration Motor drive to the Registration Roller.

■ Registration Roller

This roller aligns the leading edge of the sheet to correct any skew.

■ Registration Sensor

This sensor detects media as it arrives at the Registration Rollers.

■ Feed-Out Sensor

This sensor detects the media as it leaves the Tray 3 Feed Rollers.

■ Transfer Unit Entrance Sensor

Detects the media as it leaves the Registration Roller #1.

■ Lift Motor

This motor lifts the tray’s base plate raising the media to the pre-feed position.

■ Feed Motor

This motor drives the Feed Rollers to pick paper from the tray and position it at the Registration Roller.

■ Low Paper Sensor

The actuator lowers as print media is used in the tray. When the actuator lowers to a pre-determined position, it blocks the sensor to trigger a low paper status.

Duplex Unit

The Duplex Unit receives media diverted to the Side Exit by the Exit Gate. The media is detected by the Duplex Entrance Sensor and drawn into the Duplex Unit by the Entrance Roller. The media is inverted and exits the Duplex Unit just above Registration Roller #2. Media moves through the Duplex Unit as follows:

1. After Side 2 is printed, the Exit Gate Solenoid switches the Exit Gate to its side

output position. This directs the sheet downwards toward the Duplex Unit.

2. As the sheet reaches the Duplex Entrance Sensor, roller 1 turns, drawing the

media into the lower portion of the Duplex Unit

3. After the trailing edge of the media clears the Duplex Entrance Sensor, and with

the Duplex Reverse Sensor High, the Entrance Roller is reversed and the Duplex Solenoid is activated to position the Duplex Gate to direct the inverted media into the upper portion of the Duplex Unit.

4. The Duplex Rollers transport the media out of the Duplex Unit and into the

printer where Side 1 is printed. This portion of the duplex path is monitored by the Front and Rear Duplex Sensors.

Theory of Operation 2-35

Duplex Gate

Exit Gate

Duplex Entrance Sensor

Roller (1)

Motor A

Motor B

Duplex Reverse

■ Duplex Entrance Sensor

Roller (2)

Rear Duplex Sensor

Roller (3)

Roller (4)

Roller (5)

Front Duplex Sensor

Detects the leading edge of the media and signals the Duplex Motor to begin rotation in the forward direction.

■ Duplex Gate Solenoid

Activates the Duplex Gate directing media to the Duplex Transport Rollers.

■ Duplex Reverse Sensor

Detects media in the lower portion of the Duplex Unit and signals the Duplex Motor to reverse rotation.

■ Duplex Front and Rear Sensors

Monitor media transport through the upper portion of the Duplex Unit.

s7400-034

■ Duplex Entrance Roller

Drive the media into the Duplex Unit.

■ Duplex Transport Rollers

Transport the media through the Duplex Unit and drive the sheet into the primary paper path.

■ Duplex Motors

One motor drives the Duplex Entrance Roller, the other drives the Transport Rollers using a series of belts.

2-36 Phaser 7400 Color Printer Service Manual

Output Paper Path

The Phaser 7400 paper path for paper exiting the Fuser are:

■ Directed by the Exit Gate to the Top Output Tray on the Top Cover (facedown).

■ Directed by the Exit Gate to the Side Output Tray or Finisher.

■ Directed by the Exit Gate and Duplex Gate into the Duplex Unit.

Fuser and Exit

The Fuser and Exit Rollers are driven by the Fuser Motor. The Exit Rollers rotate in the direction of the arrows. The discharge path is determined by the position of Exit Gate and Duplex Gate.

Exit Rollers

Top Output Tray

Imaging Unit

Side Output Tray

Exit Gate

Duplex Gate

Fuser

Heat Roller

Pressure Roller

Fuser Motor

Drum (C)

Transfer Roller

s7400-033

Theory of Operation 2-37

Top Output Tray

The Top Output Tray is a facedown, 500-sheet tray located on the printer’s Top Cover. The tray receives paper from the Exit Assembly which includes a Job Offset Assembly for offset output capability.

Side Output Tray

The Side Output Tray is a faceup, 250-sheet tray located on the printer’s left side. Installation of the Finisher requires that this tray be closed and locked.

Finisher/Inverter

What follows is a summary of the output path through the Finisher. A detailed description of the Finisher paper path appears in Book 2, Section 2.

Paper fed from the printer’s left side exit enters the Finisher and passes through the Finisher Punch. If punching is specified, the Punch sensors align the sheet and punch the prescribed holes. The sheet is then transferred to the Compiler Tray for stacking. If stapling is specified, the stack is drawn into the Stapler and the Staple Head places a staple at the point specified then the Compiler Tray ejects the stapled stack to the Upper Tray. For Saddle stitching, the stack is drawn through the Stapler and stapled at the center point. The stapled stack continues through the Stapler and is folded in the Saddle Unit. The stapled and folded stack is delivered to the Lower Tray.

s7400-386

2-38 Phaser 7400 Color Printer Service Manual

Drive Assemblies

The following illustration shows the location for all the printer’s motors.

Toner Motors

Job Offset Motor

Imaging Unit Motors

Fuser Motor

Duplex

Motors

Transfer Unit Motor

Waste Toner Motor

Lift Motor

Feed Motor

Registration

Motor

s7400-389

Imaging Unit Drive Motors

The Imaging Unit Motors drive the Imaging Unit drums, toner Agitation Bars and Agitation Gears. Imaging Unit drive varies depending on the print mode. In addition to the developing components, the Cyan Imaging Unit Motor uses a Lift Uplink mechanism to raise the CMY Imaging Units during monochrome printing. When the Cyan Imaging Unit Motor rotates (CCW), the Lift Uplink slides to the left, and as indicated in the figure below, each Imaging Unit moves down for color printing.When the Cyan Imaging Unit Motor rotates (CW), the Lift Uplink slides to the right, the CMY Imaging Units move up for black and white printing.

Theory of Operation 2-39

ID Unit Operations During Color Printing

C-ID Unit M-ID Unit

Lift Uplink

C-ID Motor

(CCW)

ID Unit Operations During Monochrome Printing

C-ID Unit M-ID Unit

Lift Uplink

Y-ID Unit

K-ID Unit

C-ID Motor

(CW)

s7400-172

2-40 Phaser 7400 Color Printer Service Manual

Imaging Unit Drive

The four Imaging Unit Motors supply the drive to the Imaging Unit drum and Agitation Bar and Gear as shown in the following figure.

Imaging Unit Motor

Imaging Unit Drum

Agitation Gear

Agitation Bar

Imaging Unit

s7400-390

Transfer Unit Motor

The Transfer Unit motor turns clockwise driving the Transfer Unit belt. Inside the Transfer Unit are four Transfer Rollers located just under each Imaging Unit drum. When the Transfer Unit Motor and Imaging Unit Motors are activated, they carry the paper on the transfer belt to the Fuser. The voltages applied to the Transfer Rollers attract the toner image from the Imaging Unit drum to the media.

Theory of Operation 2-41

Transfer Unit Motor

s7400-360

Transfer Unit Drive

The Transfer Unit Motor supplies the drive to the transfer belt as shown in the following figure.

Transfer Unit Motor

Transfer Unit Gear

Transfer Unit Belt

Transfer Roller

Transfer Unit

s7400-391

2-42 Phaser 7400 Color Printer Service Manual

Fuser Motor

The Fuser Motor drives the Fuser Heat and Pressure Rollers, as well as the Exit Rollers. This is shown in the following figure.

Fuser Motor

Heat Roller

Pressure Roller

Exit Rollers

Fuser

s7400-392

Theory of Operation 2-43

Toner Dispense Motors

The CM and YK Toner Dispense Motors are mounted above the Imaging Unit Motors and drive the Toner Cartridge Supply Augers and Agitation Springs to deliver toner to the Imaging Units.

Toner Dispense Motors

s7400-48

2-44 Phaser 7400 Color Printer Service Manual

Duplex Drive Motors

Two motors are used to capture and transport paper in the Duplex Unit. Duplex Motor A drives the Entrance Roller CCW to capture paper, then CW to drive the media into the Transport Rollers. Motor B uses a series of belts to drive the four Transport Rollers that move media to the Registration Assembly.

Duplex

Motor A

Duplex

Motor B

s7400-483

Theory of Operation 2-45

Chassis Assemblies

Basket Assembly

The Basket Assembly allows all four Imaging Units to be raised from the Transfer Unit to facilitate jam clearance. A latch at the front of the Basket Assembly releases the locking catch.

Basket Assembly

s7400-395

The Basket Assembly is comprised of an upper and lower sub-assembly. The Upper Basket Assembly attaches to the printer frame and supports the Lower Basket Assembly. The Lower Basket Assembly connects to the Upper Basket Assembly and supports the four Imaging Units and the Waste Toner Manifold. The Lower Basket sub-assembly, or the entire Basket Assembly are available as replacement parts.

2-46 Phaser 7400 Color Printer Service Manual

Waste Toner Recovery

Waste toner recovery moves the toner collected from the Imaging Unit drums and Transfer Unit belt to the Waste Toner Reservoir located at the front of the printer. Driven by the Waste Toner Motor, separate Augers in the Waste Toner Manifold and Waste Toner Duct pull toner through a tube to the Waste Toner Reservoir. Waste toner is moved within the reservoir by another Auger driven by the Waste Toner Motor.

Waste Toner

Auger Assembly

Transfer Unit

Waste Toner Chute

Waste Toner Reservoir

s7400-397

Status of the Waste Toner Reservoir is monitored by the Engine Control Board. The Engine Control Board receives count signals from the Waste Toner Reservoir Auger Rotation Sensor located behind the Right Front Cover. This Hall-Effect sensor is activated each time a small, magnetic disk, embedded in the reservoir auger gear, passes in front of the sensor. The auger revolutions are converted into a life count.

■ Waste Toner Reservoir Detect Switch

Detects the presence of the Waste Toner Reservoir.

■ Waste Toner Reservoir Full Sensor

Detects when the Waste Toner Reservoir is full.

■ Waste Toner Reservoir Auger Rotation Sensor

Detects revolutions of the reservoir auger.

■ Waste Toner Auger Rotation Sensor

Detects revolutions of the manifold auger.

■ Waste Toner Motor

Drives augers in the Waste Toner Manifold, Waste Toner Duct, and Waste Toner Reservoir.

Theory of Operation 2-47

Registration Assembly

Shown in the following figure are the components associated with the Registration Assembly.

Temperature

Transfer Unit

Entrance Sensor

Media Thickness

Sensor

Tray 1 (MPT)

Home Position Sensor

Registration

Rollers #1

■ Tray 1 (MPT) Home Position Sensor

Detects the position of the Feed drive.

■ Registration Sensor #1

Detects the when the media’s leading edge has reached the Registration Rollers.

■ Registration Rollers #1

Driven by the Registration Motor through the Registration Clutch, the Registration Rollers work to correct media skew and transport media to the Transfer Unit belt.

Humidity Sensor

Registration

Clutch #1

Front Sensor Board

Registration

Sensor

s7400-644

■ Registration Clutch #1

Transfers drive from the Registration Motor to the Registration Rollers.

■ Transfer Unit Entrance Sensor

Detect the arrival of the media at the Transfer Unit.

■ Media Thickness Sensor

Produces a signal that varies dependent on media thickness.

■ Temperature/Humidity Sensor

Monitors environmental conditions surrounding the printer.

■ Front Sensor Board

Communicates the status of Tray 1 (MPT) and Registration Assembly sensors to the Motor Driver Board.

2-48 Phaser 7400 Color Printer Service Manual

Exit Assembly

The Exit Assembly uses rollers, solenoids, sensors, and diversion gates to handle media exiting the Fuser.

Exit Assembly

s7400-396

Exit Assembly components include:

■ Exit Gate

The Exit Gate switches the paper path. When the Exit Gate is in its resting position, paper is fed to the Top Output Tray. When it is lowered by the Exit Gate Solenoid, paper is fed to the Side Output Tray or Duplex Unit.

■ Exit Gate Solenoid

Switches the paper discharge path between the Top and Side Output Trays.

■ Side Output Tray Full Stack Sensors

These sensors use an actuator to detect when the Top or Side Output Tray is full.

■ Fuser Exit Sensor

The Fuser Exit Sensor detects whether paper remains in the output rollers.

■ Door E Detect Sensor

Detects whether Door E is open or closed.

■ Side Output Tray Detect Sensor

Detects whether the Side Output Tray is open or closed.

Theory of Operation 2-49

■ Offset Home Position Sensor

The Offset Home Position Sensor detects the roller position.

■ Job Offset Trailing Edge Sensor

Detects the trailing edge of the media as it leaves the Exit Assembly.

■ Exit Rollers

Driven by the Fuser Motor, the Exit Rollers transport media from the Fuser through the Exit Assembly. Exit Roller drive gearing is shown in the following figure.

Eject Idle Gear Z27

Eject Idle Gear Z54

Eject Idle Gear Z27

Eject Gear Z17

s7400-406

■ Duplex Gate

Actuated by the Duplex Gate Solenoid in the Duplex Unit, the Duplex Gate directs media through the upper portion of the Duplex Unit and returns it to the Registration Assembly for printing on side 2. The following figure shows the Duplex Gate linkage between the Duplex Unit and Exit Assembly

2-50 Phaser 7400 Color Printer Service Manual

Exit Assembly

Duplex Unit

Job Offset Assembly

s7400-407

■ Job Offset Motor

The Offset Motor acting through the Offset Gear shifts the media forward or backward providing offset capability. The flow diagram shows the components involved in the offset process.

OFFSET MOTOR

OFFSET GEAR

OFFSET CHUTE

OFFSET ROLLER

■ Top Output Tray Full Stack Actuator

Acutates the Top Output Tray Full Stack Sensor to limit the number of sheets sent to the tray.

Theory of Operation 2-51

Trays

Standard input trays include the 100-sheet, multi-purpose Tray 1 (MPT) and one 550-sheet universal tray. Standard output trays include a 500-Sheet facedown Top Output Tray with offset capability, and a 250-sheet faceup Side Output Tray.

Tray 1 (MPT)

The Tray 1 (MPT) feeds standard and custom size media into the printer. The printer’s Feed Motor, shared with Tray 2, drives the Tray 1 (MPT) Feed Roller to feed media from the tray. Tray 1 (MPT) components include:

■ Feed Rollers (Feed Retard and Pick)

Transport media from Tray 1 (MPT) to the Registration Assembly.

■ Tray 1 (MPT) No Paper Sensor

Detects when media is in Tray 1 (MPT).

■ Tray 1 (MPT) Level Sensor

Detects the presence of media at the Pick Roller.

■ Tray 1 (MPT) Home Position Sensor

Located in the Registration Assembly, it detects the position of the Feed drive.

■ Feed-Out Sensor #1

Detects media exiting the Tray 1 (MPT) Feed Rollers

■ OHP Sensor

Detects when transparency media is being fed to the Registration Assembly.

Feed-Out Sensor #1

Door A Interlock Switch

Level Sensor

No Paper Sensor

Pick Roller

Retard Roller

Feed Roller

Tray 1 (MPT)

Home Position Sensor

s7400-399

2-52 Phaser 7400 Color Printer Service Manual

Tray 1 (MPT) incorporates a single set of guides to establish paper width. The time required for the paper to clear the No Paper Sensor identifies the paper’s length. When media is placed in Tray 1 (MPT), the leading edge strikes the actuator of the No Paper Sensor indicating the presence of paper. As the last sheet of paper is fed from the tray the actuator drops through an opening indicating No Paper remains in the tray.

Universal Trays

The universal trays 2 through 6 include end and side guides that manually adjust to the paper loaded in the tray. These guides come into contact with the front and rear edges of the paper and hold it in position. Paper size is determined by the signal created by the guides interacting with the Paper Size Switch actuators.

End Guide

Rear Side Guide

Lift Plate

Front Side Guide

s7400-199

■ Side Guides Right and Left

The side guides move against media to align or register the width of print media in the paper feed direction.

■ Rear Guide

The Rear Guide moves to determine the length of print media in the paper feed direction. The Rear Guide contacts the Paper Size Switch actuators to detect the paper size loaded in the tray.

■ Lift Plate

The Lift Plate is raised by the Lift Motor to position the media for picking.

Theory of Operation 2-53

Universal Feeder

Feeder Board

Level Sensor No Paper Sensor

Feed-Out Sensor

s7400-571

■ Level Sensor

The Level Sensor uses an actuator to determine whether paper in the tray is lifted to the optimum feeding position. When the flag of the actuator leaves the sensing area, the sensor detects that the paper has been lifted.

■ Feed-Out Sensor

The Feed-Out Sensor detects a paper jam in the tray by the paper position and sensor transition time.

■ No Paper Sensor

The No Paper Sensor uses an actuator to determine whether the tray is empty. When the actuator lowers, the No Paper Sensor signal goes High indicating an empty tray.

■ Feeder Board

The Feeder Board communicates sensor information to the Motor Driver Board.

Side Output Tray

The Side Output Tray provides 250-sheets of faceup output capacity. Included is a Paper Support that rotates 180 degrees to support the stack, and a latching door for printers equipped with a Finisher. Stack level is monitored by The Side Output Tray Full Stack Sensor mounted in the Exit Assembly.

2-54 Phaser 7400 Color Printer Service Manual

Electrical

The following provides an overview of the major electrical components. Additional detail is located in Section 10, Wiring Diagrams.

LED Relay Board

Registration Sensor Board

CRUM Reader Board

Rear Sensor Board

CRUM Antenna

Duplex Control Board

Control Panel

Imaging Unit Sensor Board

Front Sensor Board

s7400-410

IP Board

Engine Control Board

Motor Driver Board

LVP S

HVPS

s7400-411

Theory of Operation 2-55

Xerox Phaser 7400 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual