Ricoh A-P4 User manual

Model A-P4
Machine Code: G147
SERVICE MANUAL
May. 12th, 2006
Subject to change

Conventions Used in This Manual
This manual uses several symbols.
Symbol What It Means
Screw
Connector
E-ring
Clip ring
Clamp
Pawls (sensors)
Spring
Throughout this service manual, "SEF" denotes "Short Edge Feed" and "LEF" denotes "Long Edge Feed".
Warnings, Cautions, Notes
In this manual, the following important symbols and notations are used.
• A Warning indicates a potentially hazardous situation. Failure to obey a Warning could result in
death or serious injury.
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• A Caution indicates a potentially hazardous situation. Failure to obey a Caution could result in minor
or moderate injury or damage to the machine or other property.
• Obey these guidelines to avoid problems such as misfeeds, damage to originals, loss of valuable
data and to prevent damage to the machine
• This information provides tips and advice about how to best service the machine.
Trademarks
• Microsoft®, Windows®, and MS-DOS® are registered trademarks of Microsoft Corporation in the
United States and /or other countries.
• PostScript® is a registered trademark of Adobe Systems, Incorporated.
• PCL® is a registered trademark of Hewlett-Packard Company.
• Ethernet® is a registered trademark of Xerox Corporation.
• PowerPC® is a registered trademark of International Business Machines Corporation.
• Other product names used herein are for identification purposes only and may be trademarks of their
respective companies. We disclaim any and all rights involved with those marks.
2

Safety Instructions
For your safety, please read this manual carefully before you service machine. Always keep this manual
handy for future reference.
- Safety Information -
Always obey the these safety precautions when using this product.
- Switches and Symbols -
Where symbols are used on or near switches on machines for Europe and other areas, the meaning of
each symbol conforms with IEC60417.
Responsibilities of the Service Technician
- Maintenance -
Maintenance shall be done only by trained customer engineers who have completed service training for
the machine and all optional devices designed for use with the machine.
- Installation -
The main machine and options can be installed by either the customer or customer engineer. The customer
or customer engineer must follow the installation instructions described in the operating instructions.
- Reference Material for Maintenance -
Maintenance shall be done with the special tools and the procedures prescribed for maintenance of the
machine described in the reference materials (service manuals, technical bulletins, operating instructions,
and safety guidelines for customer engineers).
• Use only consumable supplies and replacement parts designed for use with the machine.
3

Before Installation or Maintenance
- Shipping and Moving the Machine -
• Work carefully when lifting or moving the machine. If the machine is heavy, two or more customer
engineers may be required to prevent injuries (muscle strains, spinal injuries, etc.) or damage to the
machine if it is dropped or tipped over.
• Personnel moving or working around the machine should always wear proper clothing and footwear.
Never wear loose fitting clothing or accessories (neckties, loose sweaters, bracelets, etc. ) or casual
footwear (slippers, sandals, etc.) when lifting or moving the machine.
• Always unplug the power cord from the power source before you move the machine. Before you
move the machine, arrange the power cord so it will not fall under the machine.
- Power -
• Always turn the machine off and disconnect the power plug before doing any maintenance procedure.
After turning the machine off, power is still supplied to the main machine and other devices. To prevent
electrical shock, switch the machine off, wait for a few seconds, then unplug the machine from the
power source.
• Before you do any checks or adjustments after turning the machine off, work carefully to avoid injury.
After removing covers or opening the machine to do checks or adjustments, avoid touching electrical
components or moving parts (gears, timing belts, etc.).
• After turning the machine on with any cover removed, keep your hands away from electrical com-
ponents and moving parts. Never touch the cover of the fusing unit, gears, timing belts, etc.
- Installation, Disassembly, and Adjustments -
• After installation, maintenance, or adjustment, always check the operation of the machine to make
sure that it is operating normally. This ensures that all shipping materials, protective materials, wires
and tags, metal brackets, etc., (attached to protect the machine during shipping), have been removed
and that no tools remain inside the machine.
• Never use your fingers to check moving parts that are causing spurious noise. Never use your fingers
to lubricate moving parts while the machine is operating.
- Special Tools -
• Use only standard tools approved for machine maintenance.
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• For special adjustments, use only the special tools and lubricants described in the service manual.
Using tools incorrectly, or using tools that could damage parts, could damage the machine or cause
injuries.
During Maintenance
- General -
• Before you begin a maintenance procedure always switch the machine off.
• Disconnect the power plug from the power source.
• Allow the machine to cool for at least 10 minutes.
• Avoid touching the components inside the machine that are labeled as hot surfaces.
- Safety Devices -
• Never remove any safety device (a fuse, thermistor, etc.) unless it requires replacement. Always
replace a safety device immediately.
• Never do any procedure that defeats the function of any safety device. Modification or removal of a
safety device (fuse, thermistor, etc.) could cause a fire and personal injury. After removal and re-
placement of any safety device, always test the operation of the machine to ensure that it is operating
normally and safely.
• For replacement parts use only the correct fuses, thermistors, circuit breakers, etc. rated for use with
the machine. Using replacement devices not designed for use with the machine could cause a fire
and personal injuries.
- Organic Cleaners -
• During preventive maintenance, never use any organic cleaners (alcohol, etc.) other than those de-
scribed in the service manual. (Refer the “2. Preventive Maintenance” in the Service Manual.)
• Make sure the room is well ventilated before using any organic cleaner. Always use organic solvents
in small amounts to avoid breathing the fumes and becoming nauseous.
• Switch the machine off, unplug it, and allow it to cool before doing preventive maintenance. To avoid
fire or explosion, never use an organic cleaner near any component that generates heat.
• Wash your hands thoroughly after cleaning parts with an organic cleaner to avoid contamination of
food, drinks, etc. which could cause illness.
- Lithium Batteries -
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• Always replace a lithium battery on a PCB with the same type of battery prescribed for use on that
board. Replacing a lithium battery with any type other than the one prescribed for use on the board
could lead to an explosion or damage to the PCB.
• Never discard used batteries by mixing them with other trash. Remove them from the work site and
dispose of them in accordance with local laws and regulations regarding the disposal of such items.
- Ozone Filters -
• Always replace ozone filters as soon as their service life expires (as described in the service manual).
An excessive amount of ozone can build up around machines that use ozone filters if they are not
replaced at the prescribed time. Excessive ozone could cause personnel working around the machine
to feel unwell.
- Power Plug and Power Cord -
• Before serving the machine (especially when responding to a service call), always make sure that the
power plug has been inserted completely into the power source. A partially inserted plug could lead
to heat generation (due to a power surge caused by high resistance) and cause a fire or other
problems.
• Always check the power plug and make sure that it is free of dust and lint. Clean it if necessary. A
dirty plug can generate heat which could cause a fire.
• Inspect the length of the power cord for cuts or other damage. Replace the power cord if necessary.
A frayed or otherwise damaged power cord can cause a short circuit which could lead to a fire or
personal injury from electrical shock.
• Check the length of the power cord between the machine and power supply. Make sure the power
cord is not coiled or wrapped around any object such as a table leg. Coiling the power cord can
cause excessive heat to build up and could cause a fire.
• Make sure that the area around the power source is free of obstacles so the power cord can be
removed quickly in case of an emergency.
• Make sure that the power cord is grounded (earthed) at the power source with the ground wire on
the plug.
• Connect the power cord directly into the power source. Never use an extension cord.
• When you disconnect the power plug from the power source, always pull on the plug, not the cable.
After Installation
- Disposal of Used Items -
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• Ink is flammable. Never attempt to incinerate empty ink cartridges.
• Always dispose of used items in accordance with the local laws and regulations regarding the disposal
of such items.
• To protect the environment, never dispose of this product or any kind of waste from consumables at
a household waste collection point. Dispose of these items at one of our dealers or at an authorized
collection site.
- Points to Confirm with Operators -
At the end of installation or a service call, instruct the user about use of the machine. Emphasize the following
points.
• Show operators how to remove jammed paper and troubleshoot other minor problems by following
the procedures described in the operating instructions.
• Point out the parts inside the machine that they should never touch or attempt to remove.
• Confirm that operators know how to store and dispose of consumables such as ink cartridges, am-
monia water, paper, etc..
• Make sure that all operators have access to an operating instruction manual for the machine.
• Confirm that operators have read and understand all the safety instructions described in the operating
instructions.
• Demonstrate how to turn off the power and disconnect the power plug (by pulling the plug, not the
cord) if any of the following events occur:
1. Something has spilled into the product.
2. Service or repair of the product is necessary.
3. The product cover has been damaged.
• Caution operators about removing paper fasteners around the machine. They should never allow
paper clips, staples, or any other small metallic objects to fall into the product.
• The operator must lift the output tray to release the paper cassette before loading paper.
• Paper is loaded in the standard paper cassette without removing it from the printer.
• The operator should never attempt to remove the paper cassette from the printer.
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Safety Instructions for Toner and Ink
This section describes information for users in regard to the use of toner and ink.
Accidental Physical Exposure
- PPC Toner Exposure -
• Work carefully when removing paper jams or replacing toner bottles or cartridges to avoid spilling
toner on clothing or the hands.
• If toner is inhaled, immediately gargle with large amounts of cold water and move to a well ventilated
location. If there are signs of irritation or other problems, seek medical attention.
• If toner gets on the skin, wash immediately with soap and cold running water.
• If toner gets into the eyes, flush the eyes with cold running water or eye wash. If there are signs of
irritation or other problems, seek medical attention.
• If toner is swallowed, drink a large amount of cold water to dilute the ingested toner. If there are signs
of any problem, seek medical attention.
• If toner spills on clothing, wash the affected area immediately with soap and cold water. Never use
hot water! Hot water can cause toner to set and permanently stain fabric.
- Ink Exposure -
• If ink gets on the skin, wash the affected area immediately with soap and cold running water.
• If ink gets into the eyes, immediately flush the eyes with cold running water. If there are signs of irritation
or other problems, seek medical attention.
• If ink is swallowed, drink a strong solution of cold water and table salt to induce vomiting. Seek medical
attention.
• Ink is difficult to remove from fabric. Work carefully to avoid staining clothing when performing routine
maintenance replacing ink packs or ink cartridges.
Handling and Storing Toner and Ink
- Handling and Storing PPC Toner -
• Toner, used toner, and developer are extremely flammable. Never store toner, developer, toner
cartridges, or toner bottles (including empty toner bottles or cartridges) in a location where they will
be exposed to high temperature or an open flame.
8

• Always store toner and developer supplies such as toner and developer packages, cartridges, and
bottles (including used toner and empty bottles and cartridges) out of the reach of children.
• Always store fresh toner supplies or empty bottles or cartridges in a cool, dry location that is not
exposed to direct sunlight.
- Handling and Storing Ink -
• Ink is flammable. Never store ink packs in a location where they will be exposed to high temperature
or an open flame.
• Always store ink packs out of the reach of children.
• Always store ink packs in a cool, dry location that is not exposed to direct sunlight.
Toner and Ink Disposal
- PPC Toner Disposal -
• Never attempt to incinerate toner, used toner, or empty toner containers (bottles or cartridges). Burning
toner can explode and scatter, causing serious burns.
• Always wrap used toner and empty toner bottles and cartridges in plastic bags to avoid spillage.
Follow the local laws and regulations regarding the disposal of such items.
• Dispose of used toner and toner cartridges at one of our dealers or at an authorized collection site.
Always dispose of used toner cartridges and toner bottles in accordance with the local laws and
regulations regarding the disposal of such items.
- Ink Disposal -
• Attach the caps to empty ink containers for temporary storage to avoid accidental spillage. Return
empty ink packs and cartridges to a local dealer who can accept such items for collection and recy-
cling. If the customer decides to dispose of these items, make sure that are disposed of in accordance
to local laws and regulations.
9

Safety Precautions for This Machine
Laser Safety
The Center for Devices and Radiological Health (CDRH) prohibits the repair of laser-based optical units
in the field. The optical housing unit can only be repaired in a factory or at a location with the requisite
equipment. The laser subsystem is replaceable in the field by a qualified Customer Engineer. The laser
chassis is not repairable in the field. Customer engineers are therefore directed to return all chassis and
laser subsystems to the factory or service depot when replacement of the optical subsystem is required.
• Use of controls, or adjustment, or performance of procedures other than those specified in this manual
may result in hazardous radiation exposure.
• Turn off the main switch before attempting any of the procedures in the Laser Unit section. Laser beams
can seriously damage your eyes.
Caution Labels
Lithium Batteries (Memory Back-up)
• The danger of explosion exists if a battery of this type is incorrectly replaced. Replace only with the
same or an equivalent type recommended by the manufacturer. Discard used batteries in accordance
with the manufacturer’s instructions.
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TABLE OF CONTENTS
Conventions Used in This Manual.....................................................................................................................1
Safety Instructions...............................................................................................................................................3
Responsibilities of the Service Technician....................................................................................................3
Before Installation or Maintenance..............................................................................................................4
During Maintenance......................................................................................................................................5
After Installation..............................................................................................................................................6
Safety Instructions for Toner and Ink.................................................................................................................8
Accidental Physical Exposure........................................................................................................................8
Handling and Storing Toner and Ink............................................................................................................8
Toner and Ink Disposal..................................................................................................................................9
Safety Precautions for This Machine...............................................................................................................10
Laser Safety..................................................................................................................................................10
Caution Labels..............................................................................................................................................10
Lithium Batteries (Memory Back-up)...........................................................................................................10
1. Installation
Cautions............................................................................................................................................................21
Installation Requirements.................................................................................................................................22
Environment..................................................................................................................................................22
Machine Level..............................................................................................................................................22
Minimum Space Requirements...................................................................................................................22
Power Requirements....................................................................................................................................23
Main Machine Installation...............................................................................................................................25
Installation Overview...................................................................................................................................25
Installation Flowchart...................................................................................................................................26
LCT (B543).......................................................................................................................................................27
Accessory Check: LCT.................................................................................................................................27
Installation Procedure: LCT..........................................................................................................................27
Bridge Unit (B538)...........................................................................................................................................30
Accessory Check: Bridge Unit....................................................................................................................30
Installation Procedure: Bridge Unit.............................................................................................................30
Two-Tray Finisher (G838)...............................................................................................................................35
Accessory Check: Two Tray Finisher..........................................................................................................35
Installation Procedure: Two-Tray Finisher..................................................................................................35
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Punch Unit (B377)............................................................................................................................................39
Accessory Check: Punch Unit......................................................................................................................39
Installation Procedure: Punch Unit..............................................................................................................39
Data Overwrite Security Unit (B735).............................................................................................................43
Before You Begin…......................................................................................................................................43
Seal Check and Removal............................................................................................................................43
Installation Procedure: DOS Unit................................................................................................................44
Controller Options............................................................................................................................................47
Boards and Slots..........................................................................................................................................47
Installing SD Cards......................................................................................................................................48
Merging Applications on One SD Card....................................................................................................49
Location of SD Card Slots..................................................................................................................49
Merging Applications.........................................................................................................................50
Undo Merging.....................................................................................................................................51
Installing Controller Options.......................................................................................................................52
256 MB Memory (G818) or 128 MB Memory (B584)................................................................52
IEEE 1284 (B679)..............................................................................................................................54
IEEE 802.11b Interface Kit (G813)..................................................................................................55
USB Host Interface Unit Type 7300 (G819)...................................................................................57
2. Preventive Maintenance
PM Tables.........................................................................................................................................................59
PM Tables for the Printer.............................................................................................................................59
PM Tables for Options.................................................................................................................................62
Lubrication........................................................................................................................................................63
3. Replacement and Adjustment
Precautions........................................................................................................................................................65
General Precautions....................................................................................................................................65
Laser Unit Precautions..................................................................................................................................65
Special Tools and Lubricants...........................................................................................................................66
Special Tools................................................................................................................................................66
Lubricants......................................................................................................................................................66
Covers and Common Procedures...................................................................................................................67
Front Door.....................................................................................................................................................67
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Duplex Unit...................................................................................................................................................67
Right Upper Cover.......................................................................................................................................68
By-Pass Tray Unit.........................................................................................................................................69
Rear Covers..................................................................................................................................................70
Rear Upper Cover...............................................................................................................................70
Rear Lower Cover...............................................................................................................................70
Left Covers....................................................................................................................................................71
Operation Panel...............................................................................................................................................72
Paper Output Tray............................................................................................................................................73
Laser Unit..........................................................................................................................................................75
Caution Decal Locations.............................................................................................................................75
Laser Unit Removal......................................................................................................................................76
Polygon Mirror Motor.................................................................................................................................77
Laser Synchronization Detector..................................................................................................................78
LD Unit...........................................................................................................................................................79
LD Unit Replacement...........................................................................................................................79
Laser Beam Pitch Adjustment..............................................................................................................79
PCDU.................................................................................................................................................................82
Photoconductor Cleaning/Development Unit...........................................................................................82
Drum..............................................................................................................................................................83
Pick-Off Pawls..............................................................................................................................................84
Charge Roller and Cleaning Roller............................................................................................................85
Drum Cleaning Blade..................................................................................................................................87
ID Sensor......................................................................................................................................................87
Development.....................................................................................................................................................89
Development Unit........................................................................................................................................89
Development Filter.......................................................................................................................................90
Development Roller.....................................................................................................................................90
Developer.....................................................................................................................................................91
TD Sensor.....................................................................................................................................................93
Transfer Unit......................................................................................................................................................95
Transfer Belt Unit..........................................................................................................................................95
Transfer Belt..................................................................................................................................................96
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Transfer Belt Cleaning Blade and Toner Overflow Sensor......................................................................97
Transfer Belt Cleaning Blade..............................................................................................................97
Toner Overflow Sensor.......................................................................................................................97
Paper Feed........................................................................................................................................................98
Pick-Up, Separation, and Feed Rollers......................................................................................................98
Lower Right Cover........................................................................................................................................98
Relay/Upper Paper Feed and Lower Paper Feed Clutches....................................................................99
Upper Paper Feed Unit for Tray 1...........................................................................................................100
Lower Paper Feed Unit For Tray 2...........................................................................................................101
Paper End/Paper Height/Relay Sensors................................................................................................103
Registration Sensor....................................................................................................................................103
Tray Lift Motor............................................................................................................................................107
Feed/Development Motor.......................................................................................................................108
Idle Roller Dust Blade................................................................................................................................110
Registration Roller Dust Blade..................................................................................................................110
Fusing Unit......................................................................................................................................................112
Fusing Unit Removal..................................................................................................................................112
Fusing Unit Exit Guide...............................................................................................................................113
Hot Roller Strippers...................................................................................................................................113
Fusing Lamps..............................................................................................................................................114
Thermistors and Thermostats.....................................................................................................................116
Hot Roller/Pressure Roller........................................................................................................................117
By-Pass Tray...................................................................................................................................................120
Covers........................................................................................................................................................120
By-Pass Paper Feed and Pick-Up Roller Replacement...........................................................................121
By-Pass Separation Roller.........................................................................................................................122
Paper End Sensor, Pick-Up Solenoid.......................................................................................................123
Paper Size Sensor Board..........................................................................................................................124
By-Pass Table Removal.............................................................................................................................125
Paper Feed Clutch.....................................................................................................................................125
Duplex Unit.....................................................................................................................................................127
Duplex Cover Removal.............................................................................................................................127
Duplex Entrance Sensor............................................................................................................................128
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Duplex Exit Sensor....................................................................................................................................129
Drive Mechanisms.........................................................................................................................................130
Registration Clutch, Transfer Belt Contact Clutch....................................................................................130
Main Motor...............................................................................................................................................131
Fusing/Exit Motor.....................................................................................................................................132
Toner Supply Motor..................................................................................................................................134
Boards............................................................................................................................................................136
NVRAM......................................................................................................................................................136
Uploading NVRAM Data (SP5-824).............................................................................................136
Replacing NVRAM...........................................................................................................................137
Downloading NVRAM Data (SP5825)..........................................................................................138
HVPS...........................................................................................................................................................140
IOB.............................................................................................................................................................141
BICU Board................................................................................................................................................142
PSU.............................................................................................................................................................142
HDD and Controller Board.......................................................................................................................143
Parallelogram Image Adjustment.................................................................................................................145
4. Troubleshooting
Service Call Conditions.................................................................................................................................147
SC Code Descriptions...............................................................................................................................147
Electrical Component Defects.......................................................................................................................176
Sensors.......................................................................................................................................................176
Switches.....................................................................................................................................................177
Blown Fuse Conditions (PSU)...................................................................................................................178
BICU LEDs..................................................................................................................................................178
Controller Board Test Points.....................................................................................................................178
5. Service Tables
Service Program Mode Operation..............................................................................................................181
General Notes...........................................................................................................................................181
Entering and Leaving the Service Program Mode..................................................................................181
Printer Controller Service Mode...............................................................................................................182
Controller Service Mode Menus.....................................................................................................182
Bit Switch Programming...................................................................................................................182
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Printer Controller Bit Switch Settings...............................................................................................183
Printer Engine Service Mode....................................................................................................................184
Leaving the SP Mode................................................................................................................................185
Service Program Mode Tables.....................................................................................................................186
Service Table Key......................................................................................................................................186
Service Tables............................................................................................................................................186
SP1-xxx: Feed...................................................................................................................................186
SP2-xxx: Drum..................................................................................................................................191
SP3-xxx: Process...............................................................................................................................203
SP5-xxx: Mode.................................................................................................................................206
SP6-xxx: Peripherals.........................................................................................................................238
SP7-xxx: Data Log............................................................................................................................238
SP8XXX: Data Log 2.........................................................................................................................244
Test Pattern Printing........................................................................................................................................260
Selecting the Test Pattern..........................................................................................................................260
Printing the Test Pattern.............................................................................................................................261
SP2902-03 Printing Test Patterns............................................................................................................262
Input Check....................................................................................................................................................264
Output Check.................................................................................................................................................270
Memory Clear: SP5801...............................................................................................................................274
SMC Report...................................................................................................................................................276
Updating the Firmware..................................................................................................................................278
Setting the Machine in Firmware Update Mode....................................................................................278
Reviewing the Module Statuses...............................................................................................................279
How to Update a Module........................................................................................................................279
Printing the Self-Diagnosis Report............................................................................................................281
Uploading/Downloading NVRAM data....................................................................................................284
Uploading NVRAM Data.........................................................................................................................284
Downloading NVRAM Data....................................................................................................................285
Self-Diagnostic Mode...................................................................................................................................287
Self-Diagnostic Mode at Power On........................................................................................................287
Self-Diagnostic Test Flow..........................................................................................................................288
Detailed Self-Diagnostic Mode................................................................................................................289
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DIP Switches...................................................................................................................................................290
Controller: DIP SW2.................................................................................................................................290
I/O Board: DIP SW101...........................................................................................................................290
Using Debug Log...........................................................................................................................................291
Setting Up "Save Debug Log"..................................................................................................................291
To Switch Debug Log On.................................................................................................................291
To Select the Target for the Debug Log File....................................................................................292
To Select Events................................................................................................................................293
To select one or more memory modules for recording in the debug log file...............................295
Retrieving the Debug Log from the HDD.................................................................................................297
More About Debug Log............................................................................................................................298
SP5857-015: SD to SD (Any).........................................................................................................298
SP5857-016: Make HDD LogFile..................................................................................................298
SP5857-017: Make SD Log File....................................................................................................298
6. Details
Machine Overview........................................................................................................................................299
Component Layout....................................................................................................................................299
Paper Path..................................................................................................................................................300
Drive Layout...............................................................................................................................................301
Board Layout..................................................................................................................................................303
Board Block Diagram...............................................................................................................................303
Controller Block Diagram.........................................................................................................................305
Printing Process Overview.............................................................................................................................308
Laser Exposure...............................................................................................................................................310
Laser Exposure Overview ........................................................................................................................310
Auto Power Control (APC)........................................................................................................................311
Dual-Beam Writing...................................................................................................................................311
Laser Beam Pitch Change Mechanism....................................................................................................312
LD Safety Switches....................................................................................................................................313
Photoconductor Unit (PCDU)........................................................................................................................314
Overview of the PCDU..............................................................................................................................314
Drum Drive Mechanism............................................................................................................................315
Drum Pawls................................................................................................................................................315
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Drum Toner Seals......................................................................................................................................316
New PCDU Unit Detection ......................................................................................................................316
New Unit Detection Mechanism.....................................................................................................316
What Happens When a New Unit Is Detected..............................................................................318
Drum Charge.................................................................................................................................................319
Overview of Drum Charge.......................................................................................................................319
Charge Roller Voltage Correction...........................................................................................................320
Correction for Environmental Conditions........................................................................................320
Correction for Paper Width and Thickness (By-pass Tray only)...................................................321
ID Sensor Pattern Production Timing........................................................................................................321
Drum Charge Roller Cleaning..................................................................................................................323
Development..................................................................................................................................................324
Overview of Development........................................................................................................................324
Drive Mechanism.......................................................................................................................................325
Developer Mixing.....................................................................................................................................325
Development Bias......................................................................................................................................326
Development Bias Mechanism........................................................................................................326
Correction for Paper Width and Thickness (By-pass Tray only)...................................................326
Toner Supply..............................................................................................................................................328
Toner Bottle Replenishment Mechanism.........................................................................................328
Toner Supply Mechanism................................................................................................................329
Toner Density Control.......................................................................................................................329
Sensor Control Mode.......................................................................................................................330
TD Sensor..........................................................................................................................................330
ID Sensor...........................................................................................................................................330
Image Pixel Count Mode.................................................................................................................330
Toner Near End/End Detection...............................................................................................................331
Standard Method for Toner Near-End/End Condition Detection...............................................331
Adjustable Near-end Warning Method.........................................................................................331
Toner End Recovery..................................................................................................................................331
Toner Supply with Abnormal Sensors......................................................................................................332
Drum Cleaning and Toner Recycling...........................................................................................................333
Drum Cleaning...........................................................................................................................................333
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Toner Recycling.........................................................................................................................................334
Paper Feed.....................................................................................................................................................335
Overview of Paper Feed...........................................................................................................................335
Paper Feed Drive.......................................................................................................................................336
Pick-Up and Separation Roller Release Mechanism..............................................................................336
Paper Lift.....................................................................................................................................................337
Paper End Detection..................................................................................................................................338
Paper Registration.....................................................................................................................................339
Paper Size Detection.................................................................................................................................339
Paper Height Detection.............................................................................................................................340
By-Pass Tray...................................................................................................................................................342
Overview of By-Pass Tray.........................................................................................................................342
By-Pass Tray Operation............................................................................................................................343
By-Pass Paper Size Detection...................................................................................................................344
Duplex Unit.....................................................................................................................................................345
Overview of Duplex Unit..........................................................................................................................345
Duplex Drive Layout..................................................................................................................................346
Duplex Basic Operation...........................................................................................................................346
Paper Length Longer than A4/LT SEF.............................................................................................346
Paper Length Up to A4/LT SEF.......................................................................................................347
Duplex Unit Feed In and Exit Mechanism...............................................................................................348
Paper Feed into Duplexer................................................................................................................348
Paper Inversion and Exit from Duplexer.........................................................................................349
Image Transfer and Paper Separation.........................................................................................................350
Overview of Transfer and Separation.....................................................................................................350
Transfer Belt Drive Mechanism.................................................................................................................351
Transfer Belt Unit Contact Mechanism.....................................................................................................352
Image Transfer and Paper Separation Mechanism................................................................................353
Transfer Belt Charge.................................................................................................................................355
Transfer Belt Charge Mechanism....................................................................................................355
Correction for Paper Width and Thickness.....................................................................................355
Currents Applied to Leading Edge, Image Areas, and By-Pass Feed..........................................356
Transfer Belt Cleaning Mechanism..........................................................................................................357
19