Canon MF720 Series User manual

Revision 2.0
MF720 Series
Service Manual

Introduction
Important Notices
Application
This manual has been issued by Canon Inc. for qualified persons to learn technical theory, installation, maintenance, and repair
of products.
This manual covers all localities where the products are sold. For this reason, there may be information in this manual that does
not apply to your locality.
Corrections
This manual may contain technical inaccuracies or typographical errors due to improvements or changes in products.
When changes occur in applicable products or in the contents of this manual, Canon will release technical information as the
need arises. In the event of major changes in the contents of this manual over a long or short period, Canon will issue a new
edition of this manual.
The following paragraph does not apply to any countries where such provisions are inconsistent with local law.
Trademarks
The product names and company names used in this manual are the registered trademarks of the individual companies.
Copyright
This manual is copyrighted with all rights reserved. Under the copyright laws, this manual may not be copied, reproduced or
translated into another language, in whole or in part, without the consent of Canon Inc.
© CANON INC. 2015
Caution
Use of this manual should be strictly supervised to avoid disclosure of confidential information.
Explanation of Symbols
The following symbols are used throughout this Service Manual.
Symbols Explanation Symbols Explanation
Check.
1x
Remove the claw.
Check visually.
1x
Insert the claw.
Check a sound. Push the part.
Introduction

Symbols Explanation Symbols Explanation
1x
Disconnect the connector. Connect the power cable.
1x
Connect the connector. Disconnect the power cable.
1x
Remove the cable/wire from the
cable guide or wire saddle.
Turn on the power.
1x
Install the cable/wire to the cable
guide or wire saddle.
Turn off the power.
1x
Remove the screw.
1x
Loosen the screw.
1x
Install the screw.
1x
Tighten the screw.
Cleaning is needed. Measurement is needed.
The following rules apply throughout this Service Manual:
1. Each chapter contains sections explaining the purpose of specific functions and the relationship between electrical and
mechanical systems with reference to the timing of operation.
In the diagrams, represents the path of mechanical drive; where a signal name accompanies the symbol, the arrow
indicates the direction of the electric signal.
The expression "turn on the power" means flipping on the power switch, closing the front door, and closing the delivery unit
door, which results in supplying the machine with power.
2. In the digital circuits, '1' is used to indicate that the voltage level of a given signal is "High", while '0' is used to indicate "Low".
(The voltage value, however, differs from circuit to circuit.) In addition, the asterisk (*) as in "DRMD*" indicates that the DRMD
signal goes on when '0'.
In practically all cases, the internal mechanisms of a microprocessor cannot be checked in the field. Therefore, the operations
of the microprocessors used in the machines are not discussed: they are explained in terms of from sensors to the input of
the DC controller PCB and from the output of the DC controller PCB to the loads.
The descriptions in this Service Manual are subject to change without notice for product improvement or other purposes, and
major changes will be communicated in the form of Service Information bulletins.
All service persons are expected to have a good understanding of the contents of this Service Manual and all relevant Service
Information bulletins and be able to identify and isolate faults in the machine.
Introduction

Contents
Safety Precautions...............................................................................................1
Laser Safety........................................................................................................................................ 2
How to Handle the Laser Scanner Unit...............................................................................................2
Toner Safety........................................................................................................................................2
About Toner..........................................................................................................................................2
Handling Adhered Toner........................................................................................................................2
Notes When Handling a Lithium Battery............................................................................................. 3
Notes on Assembly/Disassembly........................................................................................................3
1. Product Overview.............................................................................................4
Product Lineups.................................................................................................................................. 5
Host Machine........................................................................................................................................5
Options................................................................................................................................................ 6
Product Features.................................................................................................................................7
Features...............................................................................................................................................7
Specifications...................................................................................................................................... 8
Specifications of Host Machine.............................................................................................................. 8
ADF Specifications..............................................................................................................................10
Wireless LAN Specifications................................................................................................................ 10
SEND Specifications........................................................................................................................... 11
FAX Specifications.............................................................................................................................. 12
Paper types / Paper size......................................................................................................................13
Name of Parts................................................................................................................................... 14
External View......................................................................................................................................14
Cross Section View............................................................................................................................. 16
Control Panel......................................................................................................................................18
2. Technical Explanation................................................................................... 19
Basic Configuration........................................................................................................................... 20
Configuration function..........................................................................................................................20
Basic Sequence..................................................................................................................................20
Document Exposure/Feeder System................................................................................................ 22
Document Exposure System................................................................................................................22
Document Feeder System................................................................................................................... 23
Controller System..............................................................................................................................26
Overview............................................................................................................................................ 26
Controls..............................................................................................................................................26
Laser Control System........................................................................................................................29
Overview............................................................................................................................................ 29
Controls..............................................................................................................................................29
Image Formation System.................................................................................................................. 30
Overview............................................................................................................................................ 30
Parts.................................................................................................................................................. 30
Image Forming Process.......................................................................................................................30
Contents
i

Controls..............................................................................................................................................35
Fixing System....................................................................................................................................41
Overview............................................................................................................................................ 41
Controls..............................................................................................................................................41
Pickup / Feed System....................................................................................................................... 44
Overview............................................................................................................................................ 44
Parts Configuration..............................................................................................................................44
Drive Configuration..............................................................................................................................45
Controls..............................................................................................................................................45
Embedded RDS................................................................................................................................ 48
Product Overview................................................................................................................................48
Service cautions..................................................................................................................................48
E-RDS Setup...................................................................................................................................... 49
FAQ................................................................................................................................................... 51
Troubleshooting.................................................................................................................................. 53
Error code and strings......................................................................................................................... 54
Setting Information Export/Import Function (DCM)........................................................................... 58
Function Overview.............................................................................................................................. 58
Specifications..................................................................................................................................... 60
Limitations.......................................................................................................................................... 62
Procedure for Exporting/Importing Service Mode Setting Information......................................................64
List of Items Which Can Be Imported....................................................................................................73
3. Periodical Service.......................................................................................... 93
Periodically Replaced Parts.............................................................................................................. 94
Durable Parts.................................................................................................................................... 95
Periodical Services............................................................................................................................96
Cleaning............................................................................................................................................ 97
4. Disassembly/Assembly................................................................................. 98
List of Parts....................................................................................................................................... 99
List of External / Internal Cover............................................................................................................ 99
List of Main Unit................................................................................................................................ 101
List of Motor / Fan............................................................................................................................. 103
List of Clutch / Solenoid / Heater / Thermistor / Switch / Speaker..........................................................104
List of Sensor....................................................................................................................................105
PCB................................................................................................................................................. 106
List of Connector...............................................................................................................................108
External Cover, Internal Cover........................................................................................................116
Location............................................................................................................................................116
External Cover, Internal Cover Disassembly/Assembly Procedure................................................ 118
Removing the Left Cover................................................................................................................... 118
Removing the Right Cover................................................................................................................. 120
Removing the Right Front Cover........................................................................................................ 121
Removing the Front Cover................................................................................................................. 122
Removing the Rear Upper Cover........................................................................................................123
Removing the Rear Cover..................................................................................................................123
Removing the Rear Lower Cover........................................................................................................123
Removing the Rear Cover Rib Unit.....................................................................................................125
Contents
ii

Removing the Upper Cover................................................................................................................125
Removing the Cartridge Tray............................................................................................................. 127
Document Exposure, Feed System.................................................................................................128
Location............................................................................................................................................128
Document Exposure, Feed System Disassembly/Assembly Procedure......................................... 130
Removing the ADF Unit + Reader Unit................................................................................................130
Separating the ADF Unit + Reader Unit.............................................................................................. 131
Removing the ADF Roller Unit............................................................................................................136
Removing the ADF Pickup Roller....................................................................................................... 137
Removing the ADF Separation Roller................................................................................................. 138
Removing the ADF Separation Pad.................................................................................................... 138
Removing the ADF Pickup Feed Unit..................................................................................................140
Removing the ADF Pickup Motor........................................................................................................141
Removing the Scoopup sheet holder.................................................................................................. 142
Removing the Reader Unit Upper Cover............................................................................................. 144
Removing the CIS Unit...................................................................................................................... 146
Removing the Reader Scanner Motor.................................................................................................151
Controller System............................................................................................................................154
Location............................................................................................................................................154
Controller System Disassembly/Assembly Procedure.................................................................... 157
Removing the Controller Cover.......................................................................................................... 157
Removing the Wireless LAN PCB (MF728Cdw / 727Cdw / 724Cdw).....................................................157
Removing the Main Controller PCB.................................................................................................... 157
Removing the Main Controller Support Plate.......................................................................................161
Removing the DC Controller PCB.......................................................................................................162
Removing the High Voltage Power Supply PCB.................................................................................. 163
Removing the Low Voltage Unit..........................................................................................................165
Removing the Fixing Sub PCB........................................................................................................... 166
Removing the Driver PCB.................................................................................................................. 167
Removing the Relay PCB.................................................................................................................. 168
Removing the Control Panel Unit........................................................................................................169
Removing the NFC PCB (MF727Cdw / 726Cdw).................................................................................171
Removing the FAX PCB (MF728Cdw / 727Cdw / 725Cdw).................................................................. 171
Removing the Off Hook PCB (MF728Cdw / 727Cdw / 725Cdn)............................................................ 172
Removing the Main Drive Unit............................................................................................................172
Removing the Duplex Reverse Drive Unit........................................................................................... 179
Removing the Fixing/Fixing Power Supply Cooling Fan Unit.................................................................180
Removing the Duplex Feeding Fan.....................................................................................................181
Removing the Speaker (MF728Cdw / 727Cdw / 725Cdn).....................................................................183
Laser Exposure System.................................................................................................................. 184
Location............................................................................................................................................184
Laser Exposure System Disassembly/Assembly Procedure...........................................................185
Removing the Laser Scanner Unit...................................................................................................... 185
Image Formation System................................................................................................................ 190
Location............................................................................................................................................190
Image Formation System Disassembly/Assembly Procedure.........................................................191
Removing the ITB Unit.......................................................................................................................191
Removing the Patch Density and Registration Sensor unit................................................................... 193
Removing the Developing Motor.........................................................................................................195
Removing the Drum Motor................................................................................................................. 196
Removing the Secondary Transfer Outer Roller...................................................................................198
Contents
iii

Fixing System..................................................................................................................................199
Location............................................................................................................................................199
Fixing System Disassembly/Assembly Procedure.......................................................................... 200
Removing the Fixing Assembly.......................................................................................................... 200
Removing the Fixing Film Unit............................................................................................................201
Removing the Fixing Pressure Roller..................................................................................................205
Removing the Fixing Motor Unit..........................................................................................................205
Pickup Feeder System.................................................................................................................... 208
Location............................................................................................................................................208
Pickup Feeder System Disassembly/Assembly Procedure.............................................................209
Removing the Cassette Pickup Roller.................................................................................................209
Removing the Cassette Separation Roller...........................................................................................210
Removing the MP Tray Pickup Roller..................................................................................................211
Removing the MP Tray Separation Pad.............................................................................................. 211
Removing the Pickup Motor............................................................................................................... 212
Removing the Pickup Unit..................................................................................................................213
Removing the MP Tray Pickup Unit.................................................................................................... 218
Removing the Secondary Transfer Feed Unit...................................................................................... 219
Removing the Delivery Unit................................................................................................................220
Removing the Duplex Feed Unit.........................................................................................................221
Removing the Re-pickup Guide Unit................................................................................................... 222
5. Adjustment................................................................................................... 224
Overview......................................................................................................................................... 225
Adjustment at Parts Replacement...................................................................................................226
Document Exposure / Feed System....................................................................................................226
Controller System..............................................................................................................................234
Laser Exposure System.....................................................................................................................239
6. Troubleshooting...........................................................................................240
Test Print.........................................................................................................................................241
Engine test print................................................................................................................................ 241
Controller test print............................................................................................................................ 241
Trouble shooting items....................................................................................................................243
Recurring faulty image.......................................................................................................................243
Confirming nip width..........................................................................................................................243
Version Upgrade............................................................................................................................. 244
Overview.......................................................................................................................................... 244
Upgrading by UST.............................................................................................................................244
Preparation.......................................................................................................................................244
Downloading System Software...........................................................................................................245
Upgrading via Internet....................................................................................................................... 247
Debug Log ......................................................................................................................................248
Function Overview.............................................................................................................................248
Conditions for collecting logs..............................................................................................................248
Collection procedure..........................................................................................................................248
7. Error/Jam/Alarm........................................................................................... 250
Outline.............................................................................................................................................251
Contents
iv

Outline..............................................................................................................................................251
Jam code..........................................................................................................................................251
Error Codes.....................................................................................................................................252
Jam Code........................................................................................................................................257
8. Service Mode................................................................................................ 259
Overview......................................................................................................................................... 260
Service Mode Menu...........................................................................................................................260
Backing up Service Mode.................................................................................................................. 260
Screen flow of Service mode..............................................................................................................261
Remote UI service mode....................................................................................................................262
COPIER...........................................................................................................................................264
DISPLAY.......................................................................................................................................... 264
I/O....................................................................................................................................................265
ADJUST........................................................................................................................................... 266
FUNCTION.......................................................................................................................................277
OPTION........................................................................................................................................... 290
COUTER.......................................................................................................................................... 295
FEEDER..........................................................................................................................................300
ADJUST........................................................................................................................................... 300
FUNCTION.......................................................................................................................................301
FAX................................................................................................................................................. 302
Lis of SSSW..................................................................................................................................... 302
List of MENU.....................................................................................................................................303
List of NUM.......................................................................................................................................303
Setting of NCU Parameters................................................................................................................304
TESTMODE.................................................................................................................................... 308
PRINT.............................................................................................................................................. 308
FAX..................................................................................................................................................309
APPENDICES....................................................................................................314
Service Tools...................................................................................................................................315
Special Tools.................................................................................................................................... 315
Solvents and Oils.............................................................................................................................. 315
General Circuit Diagram..................................................................................................................316
Print Sequence................................................................................................................................317
Backup Data ...................................................................................................................................318
Contents
v

Safety Precautions
Laser Safety..........................................2
How to Handle the Laser Scanner Unit
...........................................................2
Toner Safety..........................................2
Notes When Handling a Lithium
Battery............................................... 3
Notes on Assembly/Disassembly..........3

Laser Safety
Since radiation emitted inside the machine is completely confined within protective housings and external covers, the laser beam
cannot escape from the machine during any phase of user operation.
Therefore this machine is classified in Class 1 laser products that are regarded as safe during normal use according to
International Standard IEC60825-1.
How to Handle the Laser Scanner Unit
This machine is classified in Class 1 laser products.
However, inside the scanner unit, there is source of Class 3B laser beam and the laser beam is hazardous when entered into an
eye. So, be sure not to disassemble the laser scanner unit. No adjustment can be made to the laser scanner unit in this machine
in the field.
The label show in the following figure is attached on the laser scanner unit.
The following warnings are given to comply with Safety Principles (EN60950-1).
Diese Maschine ist der Klasse 1 der Laserprodukte zugeordnet.
Innerhalb der Scannereinheit befindet sich jedoch die Laserstrahlquelle der Klasse 3B und es ist gefährlich, wenn dieser Strahl
in die Augen gerät. Die Laserscannereinheit darf unter keinen Umständen entfernt werden. Es dürfen in diesem Umfeld der
Maschine keine Justagen an der Laserscannereinheit vorgenommen werden.
Das Etikett in folgendem Bild ist auf der Laserscannereinheit angebrachtt.
Toner Safety
About Toner
Toner is a nontoxic matter composed of plastic, iron and a trace of pigments.
CAUTION:
Never throw toner in flames to avoid explosion.
Handling Adhered Toner
• Use dry tissue paper to wipe off toner adhered to skin or clothes and wash in water.
Safety Precautions
2