Canon LBP3300 Service Manual

Service Manual

LBP3300 Series

LBP3300

Jan 19 2006

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.

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 written consent of Canon Inc.

Printed in Japan

Caution

Use of this manual should be strictly supervised to avoid disclosure of confidential information.

Symbols Used

This documentation uses the following symbols to indicate special information:

Symbol Description

Indicates an item of a non-specific nature, possibly classified as Note, Caution, or Warning.

Indicates an item requiring care to avoid electric shocks.

Indicates an item requiring care to avoid combustion (fire).

Indicates an item prohibiting disassembly to avoid electric shocks or problems.

Indicates an item requiring disconnection of the power plug from the electric outlet.

Indicates an item intended to provide notes assisting the understanding of the topic in question.

Memo

Introduction

REF.

Indicates an item of reference assisting the understanding of the topic in question.

Provides a description of a service mode.

Provides a description of the nature of an error indication.

Introduction

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."

Contents

Chapter 1 PRODUCT DESCRIPTION

1.1 Features ..................................................................................................................................................... 1- 1

1.1.1 Feature ....................................................................................................................................................................1- 1

1.2 System Construction .................................................................................................................................. 1- 1

1.2.1 System Construction ...............................................................................................................................................1- 1

1.3 Product Specifications ................................................................................................................................1- 1

1.3.1 Product Specifications .............................................................................................................................................1- 1

1.4 Name of Parts.............................................................................................................................................1- 2

1.4.1 External View...........................................................................................................................................................1- 2

1.4.2 Cross Sectional Views.............................................................................................................................................1- 3

1.5 Using the Machine......................................................................................................................................1- 4

1.5.1 Control Panel...........................................................................................................................................................1- 4

1.6 Safety ......................................................................................................................................................... 1- 4

1.6.1 Safety of Laser Light................................................................................................................................................1- 4

1.6.2 Regulations Under the Center for Devices and Radiological Health (CDRH) .........................................................1- 4

1.6.3 Safety of Toner........................................................................................................................................................1- 4

1.6.4 Handling the Laser Unit ...........................................................................................................................................1- 4

Chapter 2 TECHNICAL REFERENCE

2.1 Functional Configuration............................................................................................................................. 2- 1

2.1.1 Outline .....................................................................................................................................................................2- 1

2.2 Basic Sequense..........................................................................................................................................2- 1

2.2.1 Basic Operation Sequence......................................................................................................................................2- 1

2.2.2 Power-on sequence.................................................................................................................................................2- 1

2.3 LASER EXPOSURE SYSTEM ...................................................................................................................2- 2

2.3.1 Overview/Configuration ...........................................................................................................................................2- 2

2.3.1.1 Outline...................................................................................................................................................................................... 2- 2

2.3.1.2 Laser Control Circuit ................................................................................................................................................................ 2- 3

2.3.2 Controlling the Laser Activation Timing ...................................................................................................................2- 5

2.3.2.1 Laser emission control ............................................................................................................................................................. 2- 5

2.3.2.2 Horizontal synchronous control................................................................................................................................................ 2- 5

2.3.3 Laser Control ...........................................................................................................................................................2- 5

2.3.3.1 Automatic power control (APC)................................................................................................................................................ 2- 5

2.3.3.2 Image masking control ............................................................................................................................................................. 2- 5

2.3.4 Laser Scanner Motor Control ..................................................................................................................................2- 6

2.3.4.1 Outline...................................................................................................................................................................................... 2- 6

2.3.4.2 Scanner motor speed control................................................................................................................................................... 2- 7

2.3.4.3 Scanner motor failure detection ............................................................................................................................................... 2- 7

2.4 IMAGE FORMATION SYSTEM.................................................................................................................. 2- 7

2.4.1 Overview/Configuration ...........................................................................................................................................2- 7

2.4.1.1 Outline...................................................................................................................................................................................... 2- 7

2.4.1.2 Print Process............................................................................................................................................................................ 2- 8

2.4.1.3 Electrostatic latent image formation block ............................................................................................................................... 2- 8

2.4.1.4 Development block .................................................................................................................................................................. 2- 9

2.4.1.5 Transfer block ........................................................................................................................................................................ 2- 10

2.4.1.6 Fixing block ............................................................................................................................................................................ 2- 11

2.4.1.7 Photosensitive drum cleaning block....................................................................................................................................... 2- 11

2.4.2 High-Voltage Control .............................................................................................................................................2- 11

2.4.2.1 Outline.................................................................................................................................................................................... 2- 11

2.4.2.2 Primary charging bias generation .......................................................................................................................................... 2- 12

2.4.2.3 Developing bias generation ................................................................................................................................................... 2- 12

Contents

2.4.2.4 Transfer charging bias generation ......................................................................................................................................... 2- 12

2.4.2.5 Fixing bias generation ............................................................................................................................................................ 2- 13

2.4.2.6 Cartridge presence detection ................................................................................................................................................. 2- 13

2.5 PICKUP AND FEEDING SYSTEM........................................................................................................... 2- 13

2.5.1 Overview/Configuration..........................................................................................................................................2- 13

2.5.1.1 Outline.................................................................................................................................................................................... 2- 13

2.5.2 Detecting Jams ......................................................................................................................................................2- 14

2.5.2.1 Jam Detection Outline............................................................................................................................................................ 2- 14

2.5.2.2 Delay Jams ............................................................................................................................................................................ 2- 15

2.5.2.3 Stationary Jams ..................................................................................................................................................................... 2- 15

2.5.2.4 Other Jams ............................................................................................................................................................................ 2- 15

2.5.3 Cassette Pickup.....................................................................................................................................................2- 15

2.5.3.1 Cassette pick-up .................................................................................................................................................................... 2- 15

2.5.4 Multi-purpose Pickup .............................................................................................................................................2- 15

2.5.4.1 Manual feed ........................................................................................................................................................................... 2- 15

2.5.5 Duplex Feeding......................................................................................................................................................2- 16

2.5.5.1 Outline.................................................................................................................................................................................... 2- 16

2.5.5.2 Operation ............................................................................................................................................................................... 2- 17

2.6 EXTERNAL AND CONTROLS SYSTEM ................................................................................................. 2- 17

2.6.1 Fan.........................................................................................................................................................................2- 17

2.6.1.1 Fan motor control ................................................................................................................................................................... 2- 17

2.6.2 Power Supply.........................................................................................................................................................2- 18

2.6.2.1 Power Supply ......................................................................................................................................................................... 2- 18

2.6.2.2 Protective Functions .............................................................................................................................................................. 2- 19

2.7 ENGINE CONTROL SYSTEM ................................................................................................................. 2- 20

2.7.1 Video Controller .....................................................................................................................................................2- 20

2.7.1.1 Outline.................................................................................................................................................................................... 2- 20

2.7.1.2 Outline of Operation by Block ................................................................................................................................................ 2- 20

2.7.2 Engine Controller ...................................................................................................................................................2- 20

2.7.2.1 Outline.................................................................................................................................................................................... 2- 20

2.8 FIXING UNIT/DELIVERY SYSTEM.......................................................................................................... 2- 22

2.8.1 Overview/Configuration..........................................................................................................................................2- 22

2.8.1.1 Outline.................................................................................................................................................................................... 2- 22

2.8.2 Various Control Mechanisms.................................................................................................................................2- 23

2.8.2.1 Fixing Temperature Control ................................................................................................................................................... 2- 23

2.8.2.2 Protective Functions .............................................................................................................................................................. 2- 24

Chapter 3 DISASSEMBLY AND ASSEMBLY

3.1 EXTERNAL AND CONTROLS SYSTEM ................................................................................................... 3- 1

3.1.1 Rear Cover...............................................................................................................................................................3- 1

3.1.1.1 Preparation for removing the rear cover unit. .......................................................................................................................... 3- 1

3.1.1.2 Removing the rear cover unit. .................................................................................................................................................. 3- 1

3.1.2 Right Cover..............................................................................................................................................................3- 1

3.1.2.1 Detaching the right cover ......................................................................................................................................................... 3- 1

3.1.3 Left Cover ................................................................................................................................................................3- 1

3.1.3.1 Detaching the left cover ........................................................................................................................................................... 3- 1

3.1.4 Upper Cover.............................................................................................................................................................3- 1

3.1.4.1 Preparation for detaching the upper cover unit ........................................................................................................................ 3- 1

3.1.4.2 Detaching the upper cover unit ................................................................................................................................................ 3- 2

3.1.5 Front Cover..............................................................................................................................................................3- 2

3.1.5.1 Preparation for removing the front cover unit........................................................................................................................... 3- 2

3.1.5.2 Removing the front cover unit .................................................................................................................................................. 3- 2

3.1.6 Main Drive Unit ........................................................................................................................................................3- 2

3.1.6.1 Preparation for removing the main drive assembly.................................................................................................................. 3- 2

3.1.6.2 Removing the main drive assembly ......................................................................................................................................... 3- 2

3.1.7 Duplexing Drive Unit ................................................................................................................................................3- 3

3.1.7.1 Removing the duplexing drive assembly ................................................................................................................................. 3- 3

3.1.8 Operation Panel Unit................................................................................................................................................3- 3

Contents

3.1.8.1 Detaching the control panel ..................................................................................................................................................... 3- 3

3.1.9 Engine controller board ...........................................................................................................................................3- 4

3.1.9.1 Preparation for removing the engine controller PCB ............................................................................................................... 3- 4

3.1.9.2 Removing the engine controller PCB ....................................................................................................................................... 3- 4

3.1.10 Duplexing Driver Board..........................................................................................................................................3- 4

3.1.10.1 Preparation for removing the duplexing driver PCB ............................................................................................................... 3- 4

3.1.10.2 Removing the duplexing driver PCB ...................................................................................................................................... 3- 4

3.1.11 Video Controller Board ..........................................................................................................................................3- 5

3.1.11.1 Removing the video controller PCB ....................................................................................................................................... 3- 5

3.1.12 USB Board.............................................................................................................................................................3- 5

3.1.12.1 Removing the USB PCB ........................................................................................................................................................ 3- 5

3.1.13 Door Switch ...........................................................................................................................................................3- 5

3.1.13.1 Removing the door switch ...................................................................................................................................................... 3- 5

3.1.14 Main Body Fan.......................................................................................................................................................3- 5

3.1.14.1 Preparation for removing the fan............................................................................................................................................ 3- 5

3.1.14.2 Removing the fan ................................................................................................................................................................... 3- 6

3.2 LASER EXPOSURE SYSTEM ...................................................................................................................3- 6

3.2.1 Laser Scanner Unit..................................................................................................................................................3- 6

3.2.1.1 Preparation for removing the laser scanner unit ...................................................................................................................... 3- 6

3.2.1.2 Removing the laser scanner unit ............................................................................................................................................. 3- 6

3.3 IMAGE FORMATION SYSTEM.................................................................................................................. 3- 6

3.3.1 Transfer Charging Roller .........................................................................................................................................3- 6

3.3.1.1 Removing the transfer corona roller......................................................................................................................................... 3- 6

3.4 PICKUP AND FEEDING SYSTEM .............................................................................................................3- 6

3.4.1 Cassette Pickup Roller ............................................................................................................................................3- 6

3.4.1.1 Cassette pick-up roller ............................................................................................................................................................. 3- 6

3.4.2 Cassette Pickup solenoid ........................................................................................................................................3- 6

3.4.2.1 Preparation for removing the cassette pick-up solenoid .......................................................................................................... 3- 6

3.4.2.2 Removing the cassette pick-up solenoid ................................................................................................................................. 3- 6

3.4.3 Cassette Separation Pad......................................................................................................................................... 3- 7

3.4.3.1 Removing the separation pad .................................................................................................................................................. 3- 7

3.4.4 Multi-purpose Pickup Solenoid ................................................................................................................................3- 7

3.4.4.1 Preparation for removing the manual pick-up solenoid............................................................................................................ 3- 7

3.4.4.2 Removing the manual pick-up solenoid ................................................................................................................................... 3- 7

3.4.5 Registration Roller ...................................................................................................................................................3- 7

3.4.5.1 Preparation for removing the registration roller........................................................................................................................ 3- 7

3.4.5.2 Removing the registration roller ............................................................................................................................................... 3- 7

3.4.6 Main Motor...............................................................................................................................................................3- 7

3.4.6.1 Preparation for removing the main motor ................................................................................................................................ 3- 7

3.4.6.2 Removing the main motor ........................................................................................................................................................ 3- 7

3.4.7 Reversal Solenoid ...................................................................................................................................................3- 7

3.4.7.1 Preparation for removing the reverse solenoid ........................................................................................................................ 3- 7

3.4.7.2 Removing the reverse solenoid ............................................................................................................................................... 3- 7

3.4.8 Duplexing Unit .........................................................................................................................................................3- 8

3.4.8.1 Preparation for removing the duplexing unit ............................................................................................................................ 3- 8

3.4.8.2 Removing the duplexing unit.................................................................................................................................................... 3- 8

3.5 FIXING SYSTEM ........................................................................................................................................3- 8

3.5.1 Fixing Unit................................................................................................................................................................3- 8

3.5.1.1 Preparation for removing the fixing assembly .......................................................................................................................... 3- 8

3.5.1.2 Removing the fixing assembly ................................................................................................................................................. 3- 8

3.5.2 Fixing Film Unit........................................................................................................................................................ 3- 9

3.5.2.1 Preparation for removing the fixing film unit............................................................................................................................. 3- 9

3.5.2.2 Removing the fixing film ........................................................................................................................................................... 3- 9

3.5.3 Fixing Pressure Roller ...........................................................................................................................................3- 10

3.5.3.1 Preparation for removing the fixing pressure roller ................................................................................................................ 3- 10

3.5.3.2 Removing the fixing pressure roller ....................................................................................................................................... 3- 10

Chapter 4 MAINTENANCE AND INSPECTION

Contents

4.1 Periodically Replaced Parts ....................................................................................................................... 4- 1

4.1.1 Periodically Replaced Parts.....................................................................................................................................4- 1

4.2 Consumables ............................................................................................................................................. 4- 1

4.2.1 Life Expectancy of Consumable Parts.....................................................................................................................4- 1

4.3 Periodical Service....................................................................................................................................... 4- 1

4.3.1 Periodic Service.......................................................................................................................................................4- 1

4.4 Cleaning ..................................................................................................................................................... 4- 1

4.4.1 Cleaning During Service Visit ..................................................................................................................................4- 1

Chapter 5 TROUBLESHOOTING

5.1 MEASUREMENT AND ADJUSTMENT......................................................................................................5- 1

5.1.1 Test Print..................................................................................................................................................................5- 1

5.1.1.1 Test Print.................................................................................................................................................................................. 5- 1

5.1.2 Mechanical Adjustment............................................................................................................................................5- 1

5.1.2.1 Checking the Nip Width (fixing pressure roller)........................................................................................................................ 5- 1

5.2 SERVICE TOOLS ...................................................................................................................................... 5- 2

5.2.1 Standard Tools.........................................................................................................................................................5- 2

5.2.2 Special Tools ...........................................................................................................................................................5- 2

5.2.3 Solvent/Oil List.........................................................................................................................................................5- 2

5.3 ERROR CODE TABLE............................................................................................................................... 5- 2

5.3.1 Error Code ...............................................................................................................................................................5- 2

Chapter 6 APPENDIX

6.1 OUTLINE OF ELECTRICAL COMPONENTS ............................................................................................ 6- 1

6.1.1 Clutch/Solenoid........................................................................................................................................................6- 1

6.1.1.1 Solenoid ................................................................................................................................................................................... 6- 1

6.1.2 Motor........................................................................................................................................................................6- 1

6.1.2.1 Motor ........................................................................................................................................................................................ 6- 1

6.1.3 Fan...........................................................................................................................................................................6- 2

6.1.3.1 Fan ........................................................................................................................................................................................... 6- 2

6.1.4 Sensor......................................................................................................................................................................6- 2

6.1.4.1 Sensor...................................................................................................................................................................................... 6- 2

6.1.5 PCBs........................................................................................................................................................................6- 3

6.1.5.1 PCB.......................................................................................................................................................................................... 6- 3

Chapter 1 PRODUCT DESCRIPTION

Contents

1.1 Features ..........................................................................................................................................................................1-1

1.1.1 Feature.......................................................................................................................................................................................... 1-1

1.2 System Construction ......................................................................................................................................................1-1

1.2.1 System Construction .................................................................................................................................................................... 1-1

1.3 Product Specifications....................................................................................................................................................1-1

1.3.1 Product Specifications ................................................................................................................................................................. 1-1

1.4 Name of Parts.................................................................................................................................................................1-2

1.4.1 External View .............................................................................................................................................................................. 1-2

1.4.2 Cross Sectional Views ................................................................................................................................................................. 1-3

1.5 Using the Machine .........................................................................................................................................................1-4

1.5.1 Control Panel ............................................................................................................................................................................... 1-4

1.6 Safety .............................................................................................................................................................................1-4

1.6.1 Safety of Laser Light ................................................................................................................................................................... 1-4

1.6.2 Regulations Under the Center for Devices and Radiological Health (CDRH)............................................................................ 1-4

1.6.3 Safety of Toner ............................................................................................................................................................................ 1-4

1.6.4 Handling the Laser Unit............................................................................................................................................................... 1-4

1.1 Features

Chapter 1

1.1.1 Feature

1. Compact, high-speed and high-resolution printer

Regardless of its compact size that enables an installation on side of desks, this printer realizes the printing speed of 21 pages per minute in letter-size paper with the resolution of 600 dpi.

2. Short wait time and low power consumption

The printer utilizes the on-demand fixing method that turns on the heater only during print operations. This shortens wait time, and enables low power consumption during stand by period.

3. Automatic duplex printing

The printer enables an automatic duplex printing by installing the duplexing unit as a standard equipment in the printer.

1.2 System Construction

1.2.1 System Construction

F-1-1 T-1-1

[1] Paper Feeder PF-35 [2] Network Board NB-C1

0011-2880

0011-5497

1.3 Product Specifications

1.3.1 Product Specifications

Body installation method desktop page printer Photosensitive medium OPC drum Exposure method semiconductor laser Development method Toner projection development Transfer method by roller Separation method by curvature Cassette pickup method by pad Multifeeder pickup method by pad Drum cleaning method by blade Fixing method on-demand Delivery method face-down/face-up Toner supply type by toner cartridge

Warm-up time in standby: 0 sec (at power-on: 10 sec or less) Print area top: 5 mm; bottom: 5 mm; left/right: 5 mm (if envelope, top, bottom, left,

Printing resolution 600dpi First print time 9 sec or less (approx.; A4) Print speed (A4) 21 pages/min (approx.) Cassette paper size A4, B5, A5, Legal, Letter, Executive Multi-purpose paper size A4, B5, A5, Legal, Letter, Executive, Envelope DL, Envelope COM10,

Cassette paper type plain paper (64 to 90 g/m2), heavy paper (91 to 120 g/m2), recycled

Multi-purpose paper type plain paper (64 to 90 g/m2), heavy paper (91 to 163 g/m2), recycled

Cassette capacity 250 sheets (approx.; plain paper, 64 g/m2) Multi-purpose capacity 1 sheet Delivery tray stack 65sheets (Face-down) /1sheet(Face-up Output Slot) Memory 8 MB (internal; no optional memory available)

about 6000 prints (A4, single-sided; at 5% image ratio)

right: 10 mm)

Envelope C5, Envelope Monarch, Index Card, Custom Paper Size (width

76.2 to 215.9 mm, length 127.0 to 355.6 mm)

paper,

paper, transparency, label paper, envelop (DL, COM10, C5, Monarch, B5)

0011-2522

1-1

Chapter 1

1.4 Name of Parts

1.4.1 External View

Operating environment (Temperature range)

Operating environment (Humidity range)

Noise 52.8 dB or less (during printing; based on ISO9296; announced noise

Power supply rating AC100V±10% (50/60Hz ±2Hz) Power consumption (Maximum) 790W or less (approx.; 20 deg C; for input of rated power supply;

Dimensions 370 (W) x 375 (D) x 258 (H)mm Weight printer: Approx;11kg; toner cartridge: Approx,0.8kg(2.5K) Option paper feeder

10 to 32.5 deg C

20% to 80% RH

emission)

including peak value lasting 1 sec or more)

[2]

[1]

[9]

[8]

[7]

[3] [4]

0011-2877

[5][6]

[15]

[14]

[13]

F-1-2

[1] Face-down Output Tray [9] Front Cover [2] Control Panel [10] Expansion Slot [3] Right cover [11] USB Connector [4] Power Switch [12] Left cover [5] Paper Cassette [13] Duplex Unit Cover [6] Manual Feed Slot [14] Power Socket [7] Manual Feed Slot Cover [15] Output Selection Cover [8] Paper Guides

[12]

[10]

[11]

1-2

Chapter 1

1.4.2 Cross Sectional Views

[1]

[2]

[3]

[4]

[5]

[6]

0011-2878

[7]

F-1-3

[17]

[16]

[11]

[10]

[14][15]

[1] Face-down delivery roller [10] Registration roller [2] Fixing film unit [11] Duplex pick-up roller [3] Laser/scanner unit [12] Registration shutter [4] Primary charging roller [13] Transfer charging roller [5] Developing cylinder [14] Photosensitive drum [6] Toner cartridge [15] Duplex feed roller [7] Feed roller [16] Pressure roller [8] Separation pad [17] Face-up delivery roller [9] Pick-up roller

[13]

[12]

[8][9]

1-3

Chapter 1

1.5 Using the Machine

1.5.1 Control Panel

[1] Load Paper Indicator

[2] Paper Jam Indicator Blinking A paper jam is occurring, disabling printing.

[3] Alarm Indicator

[4]Ready Indicator

[5] Cancel Job Key/Cancel Job Indicator Pressing this key enables the cancellation of the jobs in which an error is

[1] [2] [3] [4]

[5]

F-1-4

On There is no paper in any paper source.

Blinking: No paper or paper of an inappropriate size s loaded

On Service call is occurring.

Blinking An error is occurring, disabling printing.

On The printer is ready to print.

Blinking

The printer is busy performing some kind of processing or operation, such as printing, warming up, cleaning, or pausing a job.

occurring and those in progress. The indicator comes on while pressing the key. The indicator blinks while a job is in the cancellation process.

0011-2879

1.6 Safety

1.6.1 Safety of Laser Light

Laser light can prove to be hazardous to the human body. The machine's laser unit is fully enclosed in a protective housing and external covers so that its light will not escape outside as long as the machine is used normally.

1.6.2 Regulations Under the Center for Devices and Radiological Health (CDRH)

The CDRH of the US Food and Drug Administration put into effect regulations governing the sale of laser products in the US on August 2, 1976. These regulations apply to all laser products produced on and after August 1, 1976, and a laser product cannot be sold unless it has been certified to comply with the regulations. The following is the label used to indicate that the product has been certified under the regulations, and all laser products sold in the US must bear the label.

F-1-5

1.6.3 Safety of Toner

The machine's toner is a non-toxic material composed of plastic, iron, and small amounts of dye.

Do not put the toner into fire. It may explode.

Toner on the Skin or Clothes

1. If your skin or clothes came into contact with toner, use dry tissue to remove the toner, and then wash with water.

2. Do not use warm or hot water, which will cause the toner to jell, permanently fusing it with the fibers of the clothes.

3. Do not bring toner into contact with vinyl material. They are likely to react with each other.

1.6.4 Handling the Laser Unit

The laser scanner unit emits invisible laser light inside it. If exposed to laser light, the human eye can irreparably be damaged. Never attempt to disassemble the laser scanner unit. (It is not designed for servicing in the field). The covers around the laser scanner unit are identified by the following label.

0011-2523

0011-2524

0011-2525

0011-2526

1-4

DANGER

CAUTION ATTENTION VORSICHT ATTENZIONE PRECAUCION VARO! VARNING!

RAYONNEMENT LASER INVISIBLE EN CAS D'O UVERTURE.

EXPOSITION DANGEREUSE AU FAISCEAU.

UNSICHTBARE LASERSTRAHLUNG. WENN ABDECKUNG GEOFFNET.

NICHT DEM STRAHL AUSSETZEN.

RADIAZIONE LASER INVISIOILE IN CASO DI APERTURA. EVITARE L'ESPOSIZIONE AL FASCIO.

RADIACION LASER INVISIBLE CUANDO SE ABRE. EVITAR EXPONERSE AL RAYO.

AVATTAESSA OLET ALTTIINA NAKYMATTOMALLE LASERSATEILYLLE. ALA KATSO SATEESEEN.

OSYNLIG LASERSTRALNING NAR DENNA DEL AR OPPNAD. BETRAKTA EJ STRALEN.

Invisible laser radiation when open. AVOID DIRECT EXPOSURE TO BEAM.

INVISIBLE LASER RADIATION WHEN OPEN. AVOID EXPOSURE TO BEAM.

F-1-6

Chapter 1

1-5

Chapter 2 TECHNICAL REFERENCE

Contents

2.1 Functional Configuration ...............................................................................................................................................2-1

2.1.1 Outline.......................................................................................................................................................................................... 2-1

2.2 Basic Sequense...............................................................................................................................................................2-1

2.2.1 Basic Operation Sequence ........................................................................................................................................................... 2-1

2.2.2 Power-on sequence ...................................................................................................................................................................... 2-1

2.3 LASER EXPOSURE SYSTEM.....................................................................................................................................2-2

2.3.1 Overview/Configuration .............................................................................................................................................................. 2-2

2.3.1.2 Laser Control Circuit.......................................................................................................................................................................................2-3

2.3.2 Controlling the Laser Activation Timing..................................................................................................................................... 2-5

2.3.2.1 Laser emission control ....................................................................................................................................................................................2-5

2.3.2.2 Horizontal synchronous control ......................................................................................................................................................................2-5

2.3.3 Laser Control ............................................................................................................................................................................... 2-5

2.3.3.1 Automatic power control (APC) .....................................................................................................................................................................2-5

2.3.3.2 Image masking control ....................................................................................................................................................................................2-5

2.3.4 Laser Scanner Motor Control....................................................................................................................................................... 2-6

2.3.4.2 Scanner motor speed control...........................................................................................................................................................................2-7

2.3.4.3 Scanner motor failure detection ......................................................................................................................................................................2-7

2.4 IMAGE FORMATION SYSTEM.................................................................................................................................2-7

2.4.1 Overview/Configuration .............................................................................................................................................................. 2-7

2.4.1.2 Print Process....................................................................................................................................................................................................2-8

2.4.1.3 Electrostatic latent image formation block .....................................................................................................................................................2-8

2.4.1.4 Development block .........................................................................................................................................................................................2-9

2.4.1.5 Transfer block ...............................................................................................................................................................................................2-10

2.4.1.6 Fixing block ..................................................................................................................................................................................................2-11

2.4.1.7 Photosensitive drum cleaning block..............................................................................................................................................................2-11

2.4.2 High-Voltage Control ................................................................................................................................................................ 2-11

2.4.2.2 Primary charging bias generation..................................................................................................................................................................2-12

2.4.2.3 Developing bias generation ...........................................................................................................................................................................2-12

2.4.2.4 Transfer charging bias generation.................................................................................................................................................................2-12

2.4.2.5 Fixing bias generation ...................................................................................................................................................................................2-13

2.4.2.6 Cartridge presence detection .........................................................................................................................................................................2-13

2.5 PICKUP AND FEEDING SYSTEM...........................................................................................................................2-13

2.5.1 Overview/Configuration ............................................................................................................................................................ 2-13

2.5.2 Detecting Jams ........................................................................................................................................................................... 2-14

2.5.2.1 Jam Detection Outline...................................................................................................................................................................................2-14

2.5.2.1.1 Outline...................................................................................................................................................................................................2-14

2.5.2.2 Delay Jams ....................................................................................................................................................................................................2-15

2.5.2.2.1 Pick-up delay jam..................................................................................................................................................................................2-15

2.5.2.2.2 Delivery delay jam ................................................................................................................................................................................2-15

2.5.2.2.3 Reversing delay jam ..............................................................................................................................................................................2-15

2.5.2.3 Stationary Jams .............................................................................................................................................................................................2-15

2.5.2.3.1 Pick-up stationary jam...........................................................................................................................................................................2-15

2.5.2.3.2 Delivery stationary jam .........................................................................................................................................................................2-15

2.5.2.3.3 Reversing stationary jam .......................................................................................................................................................................2-15

2.5.2.4 Other Jams.....................................................................................................................................................................................................2-15

2.5.2.4.1 Wrapping jam........................................................................................................................................................................................2-15

2.5.2.4.2 Start-up residual jam .............................................................................................................................................................................2-15

2.5.2.4.3 Door open jam .......................................................................................................................................................................................2-15

Contents

2.5.3 Cassette Pickup .......................................................................................................................................................................... 2-15

2.5.3.1 Cassette pick-up ............................................................................................................................................................................................ 2-15

2.5.4 Multi-purpose Pickup................................................................................................................................................................. 2-15

2.5.4.1 Manual feed .................................................................................................................................................................................................. 2-15

2.5.5 Duplex Feeding.......................................................................................................................................................................... 2-16

2.5.5.1 Outline .......................................................................................................................................................................................................... 2-16

2.5.5.2 Operation ...................................................................................................................................................................................................... 2-17

2.6 EXTERNAL AND CONTROLS SYSTEM ............................................................................................................... 2-17

2.6.1 Fan.............................................................................................................................................................................................. 2-17

2.6.1.1 Fan motor control.......................................................................................................................................................................................... 2-17

2.6.2 Power Supply ............................................................................................................................................................................. 2-18

2.6.2.1 Power Supply ................................................................................................................................................................................................ 2-18

2.6.2.1.1 Low-voltage Power Supply Circuit ...................................................................................................................................................... 2-18

2.6.2.2 Protective Functions ..................................................................................................................................................................................... 2-19

2.6.2.2.1 Protective function ................................................................................................................................................................................ 2-19

2.7 ENGINE CONTROL SYSTEM ................................................................................................................................. 2-20

2.7.1 Video Controller ........................................................................................................................................................................ 2-20

2.7.1.1 Outline .......................................................................................................................................................................................................... 2-20

2.7.1.2 Outline of Operation by Block...................................................................................................................................................................... 2-20

2.7.2 Engine Controller....................................................................................................................................................................... 2-20

2.7.2.1 Outline .......................................................................................................................................................................................................... 2-20

2.8 FIXING UNIT/DELIVERY SYSTEM....................................................................................................................... 2-22

2.8.1 Overview/Configuration ............................................................................................................................................................ 2-22

2.8.1.1 Outline .......................................................................................................................................................................................................... 2-22

2.8.2 Various Control Mechanisms .................................................................................................................................................... 2-23

2.8.2.1 Fixing Temperature Control ......................................................................................................................................................................... 2-23

2.8.2.1.1 Fixing temperature control.................................................................................................................................................................... 2-23

2.8.2.2 Protective Functions ..................................................................................................................................................................................... 2-24

2.8.2.2.1 Protective function ................................................................................................................................................................................ 2-24

2.8.2.2.2 failure detection .................................................................................................................................................................................... 2-24

2.1 Functional Configuration

Chapter 2

2.1.1 Outline

The machine may be broadly divided into the following 6 functional blocks: engine control system, laser exposure system, image formation system, pickup/transport/delivery system, fixing system, and externals/auxiliary control system.

0011-2515

Laser exposure system

Image formation system

Engine control

Pickup/transport/delivery system

system

Fixing system

Externals and control system

To external device

F-2-1

2.2 Basic Sequense

2.2.1 Basic Operation Sequence

The operational sequences are controlled by the microprocessor on the engine controller PCB. The table below describes the purposes of each period, from the power switch is turned ON until the print operation is completed, and the main motor stops. See the appendix for detailed timing chart.

WAIT (WAIT period)

STBY (STANDBY)

INTR (INITIAL ROTATION period)

PRINT (Print)

LSTR (LAST ROTATION period)

Period Purpose Remarks

From the power switch is turned ON until the main motor initial drive is completed.

From the end of the WAIT period or the LSTR period until the pick-up command is input from the video controller. Or from the end of the LSTR period until the power switch is turned OFF.

From the print command is input from the video controller until the pick-up solenoid is turned ON.

From the end of the INTR period until the primary high-voltage is turned OFF.

From the primary high-voltage is turn ed OFF until the main motor stops.

T-2-1

To clear the potential of drum surface and to clean the transfer charging roller.

To keep the printer ready to print.

To stabilize the photosensitive drum sensitivity for preparation of printing.

To form the image on the photosensitive drum according to the VIDEO signals (/ VD01, VD01, /VD02, VD02) input from the video controller and transfer the toner image onto the print paper.

To deliver the last print paper completely out and clean the transfer charging roller.

Detect the presence of cartridge.

When the pick-up command is input from the video controller, the INTR period starts right after the LSTR period is completed.

2.2.2 Power-on sequence

The sequence from when the power switch is turned ON until it gets the STBY status is described in the following.

1) Power ON

2) CPU initialization

3) Video interface communication start

4) Residual paper in the printer check Check each sensor in the printer for any residual paper

5) Main motor initial drive

6) Fixing heater initial drive Drive the fixing heater to reach the targeted temperature of 100 deg C

7) Scanner motor initial drive

8) High-voltage control Detect the presence of cartridge and clean the transfer charging roller after the primary charging AC bias is turned ON

9) Failure/Abnormality check Detect the scanner failure, the fixing unit failure, and the door open during this period

10) Memory tag communication

0011-2425

0011-2428

2-1

Chapter 2

2.3 LASER EXPOSURE SYSTEM

2.3.1 Overview/Configuration

2.3.1.1 Outline

The laser/scanner system consists of the laser driver and the scanner motor etc. It is controlled by the signals sent from the engine controller and the video controller. The laser driver allows the laser diode to emit light according to the LASER CONTROL signals (CNT0, CNT1, CNT2) from the engine controller or the VIDEO signals (/VDO1, /VDO2, VDO1, VDO2) from the video controller.

0011-2430

Engine controller PCB

/ACC /DEC

Video controller PCB

/BDO /BDI CNT0 CNT1

CNT2

VDO1

/VDO1

VDO2

/VDO2

Cylindrical lens

BD sensor

Mirror

Laser driver PCB

Focusing lens

Four-sided mirror

Scanner motor

Photsensitive drum

F-2-2

The laser/scanner unit of this printer utilizes a "twin beam method" (see Note). It scans two lines simultaneously with 2 laser diodes in order to realize a high-speed laser scanning. The operational sequence of the laser/scanner unit is described below.

1) When the video controller sends a print command, the engine controller rotates the scanner motor in order to rotate the four-sided mirror.

2) When the scanner motor starts to rotate, the engine controller forces the laser to emit light with the LASER CONTROL signal and then it starts to control the scanner motor rotation.

3) The engine controller controls the scanner motor to rotate at a constant speed with the SCANNER MOTOR SPEED CONTROL signal.

4) The video controller sends the VIDEO signals to the laser driver PCB after the scanner motor rotation reaches its targeted speed.

5) The laser driver allows two laser diodes to emit light according to these signals.

6) The two laser beams pass through the collimator lens and the cylindrical lens to strike the four-sided mirror, which is rotating at a constant speed.

7) The laser beam reflected by the four-sided mirror focuses on the photosensitive drum passing through the focus lens and the reflective mirror at the front of the four-sided mirror.

8) When the four-sided mirror starts to rotate at prescribed speed, the laser beam on the photosensitive drum starts to scan the surface of the drum at its prescribed speed.

9) When the photosensitive drum rotates and the laser beam scans on the drum at each prescribed speed, the latent image is formed on the photosensitive drum.

Twin beam method

The laser unit unifies with two laser diodes (LD1, LD2). In one scanning operation, the two diodes (LD1, LD2) emit light to write two lines simultaneously. This enables a twofold printing with same printing speed.

2-2

1st scanning line 2nd scanning line 3rd scanning line 4th scanning line

Chapter 2

LD1 scanning line LD2 scanning line

Feed direction

Image area

F-2-3

2.3.1.2 Laser Control Circuit

The laser control controls the laser driver to turn the two laser diodes (LD1, LD2) ON/OFF according to the LASER CONTROL signals sent from the engine controller. The circuit diagram of the laser control is illustrated below.

0011-2436

2-3

Chapter 2

Engine

controller PCB

+5V

Video

controller PCB

J201

-12

J801

-14

VDO1 /VDO1

VDO2 /VDO2

-14 -13

Laser driver PCB

LD1

LD2

VCC

-6

-5

LD1

switching

circuit

LD2

switching

circuit

-3

-2

GND

Comparator

Reference

voltage

Comparator

IC201

Sample

CPU

/CNT0 /CNT1 /CNT2

/BDO

/BDI

The DC controller sends the VIDEO signals (VDO1, /VDO1, VDO2, /VDO2) and the LASER CONTROL signals (CNT0, CNT1, CNT2) to the logic circuit in the laser driver IC. The VIDEO signals are for image formation and the LASER CONTROL signals are for switching the operational modes of the laser. The laser driver IC controls the laser according to the combination of the CNT0, CNT1, and CNT2. The table below indicates combinations of the LASER CONTROL signals (CNT0, CNT1, CNT2).

Discharge mode L L L C802, C803 discharge Data output mode H H H Used during normal printing LD1 APC mode L H L Used during LD1 APC mode LD2 APC mode L L H Used during LD2 APC mode Force LD1, LD2 ON H L L Used during test printing Force LD1, LD2 OFF L H H Used during image masking period

This control incorporates the LASER CONTROL signals for the following 4 controls:

1) Laser emission control

2) Automatic power control (APC)

3) Horizontal synchronization control

4) Image masking control

-16

-17

-18

-13

-15

Operation mode CNT2 CNT1 CNT0 Remarks

CNT0 CNT1 CNT2

-10

-9

-8

-11

hold circuit

Logic circuit

Laser driver IC

BD PCB

F-2-4

T-2-2

Sample

hold circuit

C803C802

2-4

2.3.2 Controlling the Laser Activation Timing

Chapter 2

2.3.2.1 Laser emission control

The laser emission control controls the laser diodes (LD1, LD2) to turn ON/OFF at constant light intensity according to the VIDEO signals (VDO1, /VDO1, VDO2, /VDO2) from the video controller. When the LASER CONTROL signals (CNT0, CNT1, CNT2) are put into print mode, the laser driver turns the laser diodes ON/OFF according to the VIDEO signals.

2.3.2.2 Horizontal synchronous control

The horizontal synchronous control is to horizontally align the starting position of writing the image. The following is the sequence of this control.

1) The DC controller puts the LASER CONTROL signal into LD1APCON mode or LD2APCON mode during the unblanking interval (see Note). Accordingly, the laser driver allows the laser diode (LD1, LD2) to emit light with APC.

2) Each laser beam is sent to the BD PCB in the scanning optical path of the laser beam.

3) The BD PCB detects these laser beams, generates BD INPUT signal (/BDI), and sends it to the DC controller.

4) The DC controller generates the HORIZONTAL SYNCHRONOUS signal (/BDO) based on the /BDI signal and sends the /BPO signal to the video controller.

5) The video controller outputs the VIDEO signals (VDO1, /VDO1, VDO2, /VDO2) to the DC controller to horizontally align the starting position of writing the image, when it inputs the /BDO signal

Unblanking interval

The interval when a laser diode emits light in the non-image area.

0011-2441

0011-2445

2.3.3 Laser Control

2.3.3.1 Automatic power control (APC)

The automatic power control is to maintain the light intensity emitted from the laser diode to be constant. There are two APCs, one is the initial APC (Note 1) and the other is the between-lines APC (Note 2). Both are controlled by the laser driver in the same way. The following is the sequence of this control.

1) When the LASER CONTROL signals (CNT0, CNT1, CNT2) put into the LD1APC mode, the laser driver allows the LD1 to emit light.

2) The light intensity of the LD1 is detected by the photo diode (PD) and it is converted from current to voltage. Then it is compared with the reference voltage (voltage equivalent to the target laser light intensity).

3) The laser driver controls the laser current until it reaches the voltage level of the LD1's targeted light intensity.

4) The LD1 is turned OFF forcefully when the LASER CONTROL signal puts into the force LD OFF mode. The laser driver stores the adjusted light intensity in C802.

5) After the light intensity adjustment of LD1 is completed, the LASER CONTROL signal puts into the LD2APCON mode and the laser driver allows the LD2 to emit light with APC. The laser light intensity of LD2 is adjusted and stored in C803 as same as LD1.

0011-2442

1) Initial APC Performed during the INTER period. It adjusts the laser light intensity by APC.

2) Between-lines APC Performed during the printing period. It adjusts the laser light intensity for one line before the line starts to be written.

2.3.3.2 Image masking control

The image masking control is to prevent a laser beam emission in the non-image area except during the unblanking interval. The engine controller puts the LASER CONTROL signal into the Force LD OFF mode and turns the laser diodes (LD1, LD2) OFF forcefully, while the laser scans a non-image area except during the unblanking interval. This is called the image-masked status, and the laser diodes (LD1, LD2) do not emit light during this period even if the VIDEO signals (VDO1, /VDO1, VDO2, /VDO2) are sent. The timing to start the image masking control depends on the paper size information sent from the video controller. If the paper size measured by the top of page sensor (PS912) is smaller than the paper size information, the engine controller masks the image forcefully to prevent

0011-5815

the transfer charging roller to be soiled.

2-5

Chapter 2

/BDO

Unmasking area

2 mm

0 mm

0 mm 0 mm

F-2-5

1) The shaded area indicates the area an image can be written by the laser beam.

2) T1 indicates the area of left /right outsides 0 mm of letter sized paper despite a paper size is specified or not.

3) T2 indicates the area of 2 mm behind the leading edge of the paper (where the /BDO signal starts to output) to the trailing edge.

2.3.4 Laser Scanner Motor Control

/BDO

2.3.4.1 Outline

The scanner motor control is to rotate the scanner motor in order to strike the laser beam at the correct position on the photosensitive drum. The circuit diagram of the scanner motor control is illustrated below.

0011-2448

2-6

Chapter 2

IC201

CPU

Frequency

comparator

Reference

clock

Divider

+24VA

X201

J201

-15

-19

-20

-21

-22

/BDI

/ACC

/DEC

Video controller PCBEngine controller PCB

J801

-12

-13

-7

Laser/scanner unit

BD sensor

+24VA

J802

-4

-1

-2

-3

-1

-2

-3

-4

-3

-2

-1

Scanner driver IC

Integrated

circuit

Drive

circuit

Scanner motor

F-2-6

2.3.4.2 Scanner motor speed control

The scanner motor is 3-phase DC brushless motor unified with the hole effect device and it is unified with the drive circuit. When the printer is turned ON, the CPU (IC201) divides the oscillated frequency of the crystal oscillator (X201) and generates the reference clock. The CPU puts the SCANNER MOTOR ACCELERATION signal (/ACC) into "L" and the DECELERATION signal (/DEC) into "H", when the print command is sent from the video controller. Then the scanner driver IC rotates the scanner motor when the /ACC signal puts into "L". The scanner motor increases the rotational count only during the /ACC signal is "L". The CPU allows the laser to emit light with APC during the scanner motor is rotating. Accordingly, the BD INPUT signal (/BDI) is sent to the CPU from the BD sensor via the video controller. The CPU compares the intervals between the /BDI signal and the reference clock with the frequency comparator in the CPU, and controls the rotational count of the scanner motor by controlling the /ACC signal until the rotational count reaches its prescribed count. The CPU decreases the rotational count of the scanner motor by putting the SCANNER MOTOR DECRELATION signal (/DEC) into "L" and the ACCELERATION signal (/ACC) into "H" to stop the scanner motor.

2.3.4.3 Scanner motor failure detection

The CPU monitors the /BDI signal from the BD sensor via the video controller, and determines if the scanner motor rotates at its prescribed rotational count or not. The CPU determines the failure or the error and notifies it to the video controller under the following conditions.

1) Scanner failure When the /BDI signal is not detected within 1.5 sec. after the forced acceleration of the scanner motor is completed, it is detected for another 60 sec, and if the interval of the /BDI signal cannot be detected at specified amount during this period.

2) BD failure If the /BDI signal is not detected within 100msec. after the forced acceleration of the scanner motor. Or if the interval of the /BDI signal is not detected at a specified value for longer than 2 sec. continuously, after the scanner motor reaches its prescribed rotational count.

3) BD error

If the /BDI signal is not detected in the prescribed interval during the CPU is outputting the /BD signal to the video controller. Exceptional cases: If the door open is detected within 200 msec. after the BD error is detected, the CPU does not notify the BD error to the video controller. Also if the scanner failure or the BD failure is detected after the BD error is detected, the CPU releases the BD error.

0011-2449

0011-2450

2.4 IMAGE FORMATION SYSTEM

2.4.1 Overview/Configuration

2.4.1.1 Outline

The image formation system serves as the nerve center of the printer. It consists of the cartridge, the transfer charging roller, and the fixing unit etc. When the engine controller receives print command from the video controller, it drives the main motor in order to rotate the followings: photosensitive drum, developing cylinder, primary charging roller, transfer charging roller and pressure roller. The primary charging roller allows the surface of the photosensitive drum to charge evenness negative. At the same time, the laser beam, modulated by the VIDEO signals (VDO1, VDO2, /VDO1, /VDO2), is emitted onto the surface of photosensitive drum in order to format the latent image on the drum by the laser diode.

0011-2452

2-7

Chapter 2

The latent image formed on the photosensitive drum is transferred into a visible image by the toner on the developing cylinder and the transfer charging roller transfers it onto a print paper. Then the transferred toner onto a paper becomes a permanent image by heat and pressure in the fixing unit. After the surface of the photosensitive drum is cleaned by the cleaning blade, the drum potential is uniformed by the primary charging roller to get ready for the next print.

Laser/Scanner unit

Laser beam

Primary charging roller

Fixing unit

Fixing film unit

Cartridge

Developing cylinder

Cleaning blade

Pressure roller

Photosensitive drum

Transfer charging roller

VIDEO signals (VDO, /VDO)

Video controller PCB

Engine controller PCB

Print command

F-2-7

2.4.1.2 Print Process

The principal process of the image formation is described in this paragraph. The process can be broadly divided into 5 blocks with 7 steps. A toner image is formed on a print paper as it goes step by step in each block.

Electrostatic latent image formation block

Paper path

2. Laser beam exposure

Rotational direction of the drum

1. Primary charging

Photosensitive drum cleaning block

Delivery

1. Electrostatic latent image formation block Form an electrostatic latent image on the photosensitive drum. Step 1: Primary charging (Charge the surface of the photosensitive drum uniformed negative potential) Step 2: Laser beam exposure (Form an electrostatic latent image on the photosensitive drum)

2. Developing block Make an electrostatic latent image on the photosensitive drum visible by applying the toner on. Step 3: Development

3. Transfer block Transfer a toner image on the photosensitive drum surface onto a print paper. Step 4: Transfer (Transfer a toner on the photosensitive drum onto a print paper) Step 5: Separation (Remove a paper from the photosensitive drum)

4. Fixing block Fix a toner image on a print paper. Step 6: Fixing

5. Photosensitive drum cleaning block Clean the residual toner on the photosensitive drum. Step 7: Drum cleaning

7. Drum cleaning

Fixing block

6. Fixing

F-2-8

5. Separation 4. Transfer

Transfer block

Developing block

3. Developing

Pick-up

2.4.1.3 Electrostatic latent image formation block

This block consists of two steps and forms an electrostatic latent image on the photosensitive drum.

0011-2453

0011-2454

2-8

Chapter 2

When the last step in this block is complete, a negative electrical charge is remained in the unexposed drum surface area by the laser beam and it is removed from the exposed area. The image with a negative charge on the drum is called an "electrostatic latent image" as it is invisible to the human eyes.

-100

Exposed area

Unexposed area

-500

Time (t)

Laser beam exposure (step 2)

F-2-9

Transfer (step 4)

Primary charging (step 1)

Step 1: Primary charging

Surface electric

potential (V)

Primary charging (step 1)

Primary chargingroller

AC bias

Photosensitive drum

DC bias

F-2-10

As a preparation to form a latent image, the surface of the photosensitive drum is charged a uniform negative potential in this step. The charging method of this printer is to charge directly to the drum surface. The primary charging roller is made of a conductive rubber. To maintain the surface potential charged on the photosensitive drum uniformly, the DC bias and additional AC bias are combined. This DC bias, interlocked to the developing DC bias, changes according to the IMAGE DENSITY INFORMATION signal from the video controller. Step 2: Laser beam exposure As the laser beam scans the photosensitive drum, the potential on the exposed area gets neutralized and this area forms the electrostatic latent image.

Laser beam

Unexposed area Exposed area

F-2-11

2.4.1.4 Development block

The electrostatic latent image on the photosensitive drum surface is visualized by applying the toner in this process. This printer utilizes the projection development method by the single-component toner. Step 3: Development

0011-2455

2-9

Chapter 2

Blade

Photosensitive drum

AC bias

Cylinder Magnet

Stirrer

Developing cylinder

DC bias

F-2-12

The exposed area on the photosensitive drum is indicated positive in figure despite of the fact that the actual potential on the drum is negative. This means that the potential of the photosensitive drum is higher than that of the cylinder relative to the potential of the cylinder.

The developing unit is structured by the developing cylinder, which consists the fixed magnet, the developing cylinder rotating around the magnet and the rubber blade. The single-component developing material is called toner. The toner is mainly composed of magnetic particles and resin and it is caught onto the cylinder by the magnetic force. The toner is insulating property and it is charged negative potential by the friction force with the rotating cylinder. The area of the photosensitive drum, where the laser beam exposed, has higher potential than the toner that is charged negatively on the cylinder. That is, when this area contacts the toner layer (negatively charged), the toner jumps onto the drum surface by the potential difference between the drum surface and the cylinder (higher potential on drum side). This phenomenon is called the projection development and it visualizes the electrostatic latent image on the drum.

Developing cylinder surface potential

Drum surface potential (Exposed)

Voltage (V)

-V Time (t)

F-2-13

The developing cylinder is applied the AC bias in order to make the toner jump easier onto the drum surface and improve the contrast of the output image. The central voltage of the AC bias (1600Vp-p) changes according to the developing DC bias. This printer enables to adjust the image density by changing the potential difference between the cylinder and the photosensitive drum according to changing the developing DC bias based on the IMAGE DENSITY INFORMATION signal from the video controller.

2.4.1.5 Transfer block

The transfer block transfers the toner image on the photosensitive drum onto a print paper. Step 4: Transfer

DC bias

Drum surface potential (Unexposed)

0011-2456

Photo-

sensitive

drum

Paper

Transfer charging roller

F-2-14

The toner on the photosensitive drum surface is transferred onto a paper according to the positive charge from the back side of the paper. The transfer charging roller of this printer interlocks the photosensitive drum in order to improve the image quality. Step 5: Separation

2-10

Chapter 2

Photo-

sensitive

drum

Paper

Static charge eliminator

Transfer charging roller

F-2-15

A print paper is separated from the drum by its elasticity. (Curvature Separation) The static charge on the back side of a print paper is decreased with the electrostatic eliminator after the transfer process in order to stable the feeding operation and prevent the crescent spots of printing image under the L/L environment.

2.4.1.6 Fixing block

The toner image transferred onto a print paper through the transfer block can be smeared easily by hands since it is only attracted to the paper by the static electricity. The paper and the toner on it are fixed by pressure and fused by heat to be a permanent image in this block. Step 6: Fixing

0011-2458

Fixing film Fixing heater

Toner

Fixing film

Toner

Paper

Pressure roller

F-2-16

There is a possibility to splatter the toner when it is fixed because the toner image transferred onto a paper is attached by the positive charge from the back side of it. This printer applies the negative DC voltage to the fixing film through the pressure roller, so that the negative charge is flown to the front side of a print paper from the fixing film before it comes to the fixing heater. It results that the transferred toner is held stronger onto the paper and it is prevented from splattering. This printer utilizes the on-demand fixing method with the lower heat capacity fixing film, which warms up quickly and does not require the power supply during standby period. The feature of this method is that the wait period is shorter than 10 sec. and thus energy-saving. The fixing film is a sleeve shaped film made from the polyamide and the fluorine coats its surface to prevent the offset.

2.4.1.7 Photosensitive drum cleaning block

In the transfer block, not all toner is transferred from the photosensitive drum onto a print paper but some remains on the drum. The drum cleaning block cleans the surface of the photosensitive drum in order to keep a clear image in the following prints. Step 7: Drum cleaning

Pressure roller

0011-2459

Cleaner container

Cleaning blade

Photosensitive drum

Sweeper strip

F-2-17

The cleaning blade scrapes off the leftover toner on the drum surface to be got ready for the next print. The waste toner is kept in the cleaner container.

2.4.2 High-Voltage Control

2.4.2.1 Outline

The high-voltage power supply circuit generates the high-voltage required for the image formation. It consists of the primary charging bias circuit, the developing bias circuit, and the transfer charging bias circuit.

0011-2495

2-11

Chapter 2

The primary charging bias circuit generates the negative DC voltage and AC voltage. They are superimposed and applied to the primary charging roller. The circuit also applies the negative DC voltage to the fixing film unit through the pressure roller. In addition, this circuit detects the presence of cartridge. The developing bias circuit generates negative DC voltage and AC voltage. They are superimposed and applied to the developing cylinder. The transfer charging bias circuit generates positive or negative DC voltage and applies the positive or negative DC voltage to the transfer charging roller. These circuits are controlled by the commands from the CPU (IC201) on the engine controller. The following section describes each generation circuit.

IC201

CPU

PRDCC

PRACC

CRGSNS

DV ACC

Engine controller PCB

High-voltage power supply circuit

Primary charging bias circuit

IC301

IC301IC301

Developing bias circuit

DC voltage

generation

AC voltage generation

DC voltage

generation

circuit

Superimposed

AC voltage generation

circuit

Superimposed

circuit

Fixing film unit

J302

JP305

Primary charging roller

JP306

J300

Photosensitive drum

JP303 JP304

Developing cylinder

Pressure roller

Transfer charging bias circuit

TRPFOT

TRPWM

TRNFOT

IC301

IC502

TRCRNT

2.4.2.2 Primary charging bias generation

The primary charging bias (PR) is generated according to two signals output from the CPU: the PRIMARY CHARGING DC BIAS DRIVE signal (PRDCC) and the PRIMARY CHARGING AC BIAS DRIVE signal (PRACC). The PRDCC signal is a clock signal to generate the DC bias and the primary charging DC bias is generated according to this signal. The PRACC signal is a clock signal to generate the AC bias and the primary charging AC bias is generated according to this signal. The superimposed voltage of primary charging AC and the primary charging DC biases is applied to the primary charging roller. The primary DC bias changes with the developing DC bias in response to the image density information sent from the video controller.

2.4.2.3 Developing bias generation

The developing bias (DV) is generated according to the DEVELOPING AC BIAS DRIVE signal (DVACC) output from the CPU. The DVACC signal is a clock signal to generate the AC bias and the developing AC bias is generated according to this signal. The developing DC bias is generated according to the developing AC bias generated in the developing AC bias generation circuit. The superimposed voltage of the developing DC bias and the developing AC bias is applied to the developing cylinder. The developing DC bias changes with the primary charging DC bias, in response to the image density information sent from the video controller.

2.4.2.4 Transfer charging bias generation

The transfer bias (TR) is generated by three signals output from the CPU: the TRANSFER POSITIVE BIAS DRIVE signal (TRPFOT), the TRANSFER NEGATIVE BIAS DRIVE signal (TRNFOT), and the TRANSFER OUTPUT SWITCHING signal (TRPWM). The TRPFOT signal is a clock signal to generate the positive bias and the transfer positive bias is generated according to this signal. The TRNFOT signal is a clock signal to generate the negative bias and the transfer negative bias is generated according to this signal. The voltage of either the transfer positive bias or the transfer

Positive voltage

generatiion circuit

Negative voltage

generatiion circuit

F-2-18

JP301

Transfer charging roller

JP302

0011-2496

0011-2497

0011-2499

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