Canon PC800S, PC900S, PC960, PC981, PC940 User Manual

REVISION 0

PC860

F13-8491 TYA00001-

PC880

F13-8291 TZA00001-

PC890

F13-8242 UAA00001-

PC920

F13-8431 TVB00001F13-8441 PUD00001-

PUE00001-

F13-8461 PUH00001-

PC921

F13-8432 TVC00001-

PC940

F13-8436 TVD00001-

PC941

F13-8437 TVE00001-

PC950

F13-8231 TVF00001F13-8241 PUF00001-

PUG00001-

PC960

F13-8434 TVG00001-

PC980

F13-8232 TVH00001-

PC981

F13-8233 TVJ00001-

AUG. 1999

FY8-13GA-000

IMPORTANT

THIS DOCUMENTATION IS PUBLISHED BY CANON INC., JAPAN, TO SERVE AS A SOURCE OF REFERENCE FOR WORK IN THE FIELD. SPECIFICATIONS AND OTHER INFORMATION CONTAINED HEREIN MAY VARY SLIGHTLY FROM ACTUAL MACHINE VALUES OR THOSE FOUND IN ADVERTISING AND OTHER PRINTED MATTER.

ANY QUESTIONS REGARDING INFORMA TION CONTAINED HEREIN SHOULD BE DIRECTED TO THE COPIER SERVICE DEPARTMENT OF THE SALES COMPANY. THIS DOCUMENT ATION IS INTENDED FOR ALL SALES AREAS, AND MA Y CONTAIN INFORMATION NO T APPLICABLE TO CERTAIN AREAS.

Printed in Japan

Imprimé au Japon

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

Prepared by

OFFICE IMAGING PRODUCTS TECHNICAL SUPPORT DIVISION

CANON INC.

5-1, Hakusan 7-chome, Toride-shi, Ibaraki 302-8501 Japan

INTRODUCTION

This service manual has been prepared for the PC800/900 Series machines, providing basic information used for servicing the machines in the field so as to ensure their quality and performance.

This service manual consists of the following chapters: Chapter 1

Chapter 2 Chapter 3

Chapter 4

Chapter 5

Chapter 6

General Description

names of parts, and how originals are reproduced.

Basic Operation Exposure System

machine's exposure system. It also explains the timing at which exposurerelated mechanisms are operated, and shows how they may be disassembled/assembled and adjusted.

Image Formation System

machine's image formation system. It also explains the timing at which image formation-related mechanisms are operated, and shows how they may be disassembled/assembled and adjusted.

Pick-Up/Feeding System

machine's pickup/feeding system. It also explains the timing at which pickup/ feeding-related mechanisms are operated, and shows how they may be disassembled/assembled and adjusted.

Fixing System

fixing system. It also explains the timing at which fixing-related mechanisms are operated, and shows how they may be disassembled/assembled and adjusted.

discusses the principles of operation used for the machine's

introduces the machine's features, specifications,

explains how copies are made on a step-by-step basis.

discusses the principles of operation used for the

Chapter 7

Chapter 8

Chapter 9

Chapter 10

Chapter 11

Appendix contains a general timing chart and general circuit diagrams.

Externals/Auxiliary Mechanisms

for the machine's externals/auxiliary mechanisms. It also explains the timing at which auxiliary mechanism-related mechanisms are operated, and shows how they may be disassembled/assembled and adjusted.

ADF

explains the principles of operation of the ADF in view of electrical and mechanical functions and in relation to their timing of operation. It also shows how the unit may be disassembled/assembled and adjusted.

Installation

how the machine may be installed using step-by-step instructions.

introduces requirements for the site of installation, and shows

Maintenance and Servicing

consumables/durables and scheduled servicing charts.

Troubleshooting

adjustments, and problem identification (image fault/malfunction).

provides tables of maintenance/inspection, standards/

discusses the principles of operation used

provides tables of periodically replaced parts and

i

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, accompanies the symbol

represents the path of mechanical drive—where a signal name

, 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 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 reasons, 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.

ii

• This service manual covers the models shown in the following table. Be sure to have a good understanding of the difference from model to model before referring to this manual.

Model

PC860 PC880 PC890 PC920 PC920 PC920 PC920 PC921 PC940 PC941 PC950 PC950 PC950 PC960 PC980 PC981

Type code

TYA

TZA

UAA

PUD

PUE PUH TVB TVC TVD TVE

PUF PUG

TVF TVG TVH

TVJ

Multi-

feeder

√ √

√ √ √ √ √ √

Single feeder

√

√ √ √ √ √ √ √

Zoom

√ √ √ √ √ √ √

√ √

√ √ √ √

Default

ratio

2R2E 2R2E 2R2E 2R2E 2R2E 2R2E 3R1E 3R1E 3R1E 3R1E 2R2E 2R2E 3R1E 3R1E 3R1E 3R1E

Density

correction

switch

(SW101)

√ √ √ √ √ √

√ √

The notation “√” indicates that the item in question is available.

ADF

as

standard

√

√ √ √

Cassette

250 sheets 250 sheets 250 sheets

Universal Universal Universal Universal Universal Universal Universal Universal Universal

500 sheets

Universal 500 sheets 500 sheets

Copying

speed

(cpm) at

Direct

12 12 12 10 10 10 10 10 13 13 12 12 13 10 13 13

iii

iv

CHAPTER 1

GENERAL DESCRIPTION

This chapter provides specifications of the machine, instructions on how to operate

the machine, and an outline of copying process.

I. FEATURES ..................................1-1

II. SPECIFICATIONS .......................1-2

A. Copier....................................1-2

B. ADF .......................................1-8

III. NAMES OF PARTS................... 1-10

A . External View ..................... 1-10

B. Cross Section..................... 1-13

IV. USING THE MACHINE ............. 1-15

A. Control Panel...................... 1-15

V. ROUTINE MAINTENANCE

BY THE USER .......................... 1-17

VI. IMAGE FORMATION ................ 1-20

A. Outline ................................ 1-20

CHAPTER 1 GENERAL DESCRIPTION

I. FEATURES

1. Personal Copier with a Zoom Function and a Fixed Copyboard

• You can choose either a default enlargement/reduction ratio or any ratio between 70% and 141% in 1% increments.

2. Ecology-Conscious

• The use of a roller charging method has resulted in a considerable reduction of ozone: 0.01 ppm or less on the average, 0.02 ppm or less at maximum (1/100 to 1/1000 compared with existing Canon machines).

3. SURF Fixing Assembly

• The wait time is 0 sec (at 20°C room temperature), enabling speedy copying work immediately after power-on.

4. Various Paper Sizes

• The paper may be between A4 (LGL) and A5 (STMT) (*Using the universal cassette).

• In manual feed mode, paper may be as large as A4 (LGL) or as small as a business card.

5. All-in-One Cartridge for Simple Maintenance

• The photosensitive drum, toner case, charging roller, developing assembly, and cleaning assembly are constructed as a single entity (cartridge). The user may expect quality copy images at all times as long as he/she performs simple replacement/cleaning work.

6. Large Paper Source

• The source of paper may contain as many as 550 sheets of paper (500-sheet cassette + multifeeder; multifeeder type).

7. Separate top unit

• The machine’s top unit may be opened to make jam removal easy.

8. ADF Type

• Continuous copying is possible with the use of the ADF.

1-1

CHAPTER 1 GENERAL DESCRIPTION

II. SPECIFICATIONS

A. Copier

1. Type

Item

Body

Copyboard

Source of light

Lens

Photosensitive medium

2. Mechanisms

Item

Reproduction

Charging

Exposure

Descriptions

Desk top

Fixed

Halogen lamp (80 V/110 W for 120V-model; 150 V/160 W for 220/240 V-model)

Fixed focal point lens

OPC drum (24-mm dia.)

Table 1-201

Descriptions

Indirect static reproduction

Roller (direct charging)

Slit (moving light source)

Copy density adjustment

Development

Pickup

Separation

Fixing

Cleaning

Original orientation

Auto or manual

Dry (toner projection)

Cassette (1 pc.) Single-feeder (single-feeder type) Multifeeder (multifeeder type)

Curvature separation + static eliminator

Flat heater

Blade

Center reference (copyboard)

Table 1-202

1-2

3. Performance

CHAPTER 1 GENERAL DESCRIPTION

Item

Original type

Maximum original size

Reproduction ratio

Zoom

Wait time

First copy time

Continuous copying

Copy size

Copy paper type

Descriptions

Sheet, book, 3-D object (2kg max.) A4 (297 × 210 mm)/LGL (216 × 356 mm)

Inch/AB-configuration: 2R2E Inch-configuration: 3R1E

70% to 141% (in 1% increments*1)

0 sec (at 20°C room temperature)

10 sec or less (at 20°C room temperature; Direct, non-AE, from the cassette)

100 (max.) A4/LGL (297 × 210 mm/216 × 356 mm max.)

Business card (90 × 55 mm, min.)

Cassette:

2

Plain paper (64 to 80 g/m B5R), colored paper, recycled paper (64 to 80 g/m B5R), eco paper (80 g/m

), tracing paper (SM-1, A4R/

2

; A4R)

2

; A4R/

Manual Feeder:

2

Plain paper (52 to 128 g/m

*2

; A4R/B5R), transparency

80 paper, business card (200 g/m LTRR), recycled paper (64 to 80 g/m

2

per (80 g/m

; A4R), postcard

), tracing paper (SM-1, GNT-

*2,*4

(A4R/LTRR*3), colored

2

or less), label sheet*2 (A4R/

2

*3

; A4R/B5R), eco pa-

Double-Sided/Overlay Copying*5:

2

Plain paper (64 to 128 g/m (200 g/m

2

or less), recycled paper (64 to 80 g/m2; A4R/

B5R), eco paper (80 g/m

), colored paper, business card

2

; A4R), postcard

*3

Cassette

With claws Universal cassette (250 sheets of 80 g/m

2

paper; A4/LGL to

A5/STMT)

2

)

2

)

2

)

Multifeeder tray

Copy tray

Non-image width

250-sheet cassette (250 sheets of 80 g/m 500-sheet cassette (500 sheets of 80 g/m

5 mm deep (approx.; 50 sheets of 80 g/m

100 sheets (A4; 80 g/m

2

)

Leading edge: 2.0 ±1.5 mm (Direct; 4.0 mm or less otherwise) Left/right: 0.0 +2.0, -0.0 mm (0 +4.0, -0.0 mm for LTR)

Auto power-off

Provided (5 min, approx.; fixed)

*6

Table 1-203

1-3

CHAPTER 1 GENERAL DESCRIPTION

*1. Applies only to models with a zoom function. *2. Applies only to single pickup if the multifeeder is used. *3. Applies only to vertical feeding. *4. Upon delivery, be sure to remove each from the copy tray. *5. Be sure to remove any curling before feeding for a second time. *6. If stopped because paper ran out during copying operation, 1 hr.

1-4

4. Others

CHAPTER 1 GENERAL DESCRIPTION

Item

Operating condition

Temperature Humidity Atmospheric pressure

Power source

Serial number

Maximum power consumption

Noise

Descriptions

7.5°C to 32.5°C/44.5°F to 90.5°F 5% to 85% RH

607.95 to 1013.25 hPa (0.6 to 1 atm)

120 V 60 Hz 220/240 V 50 Hz, 60 Hz

TVBxxxxx PUDxxxxx PUHxxxxx TVCxxxxx PUExxxxx TVDxxxxx PUFxxxxx TVExxxxx PUGxxxxx TVFxxxxx TYAxxxxx TVGxxxxx TZAxxxxx TVHxxxxx UAAxxxxx TVJxxxxx

0.9 kW or less Standby: 1.2W (approx.; about 5min; reference only) Copying: 0.4kWh (approx.; reference only)

Standby: -(sound power level by ISO) Copying: (sound power level by ISO)

• Single-feeder type: 68 dB or less

• Multifeeder type: 66 dB or less

Ozone

Dimensions (WxDxH)

Weight (including the cassette)

Consumables

*1. 250-sheet cassette type *2. 500-sheet cassette type

0.01 ppm or less (average; 0.02 ppm or less, max.)

Copyboard Type

484.9 × 448.2 × 297.5 mm

*1

/ 329.0 mm

19.1 in. × 17.6 in × 11.7 in*1/ 13.0 in

*2

ADF Type

*1

484.9 × 448.2 × 358.3 mm

/ 389.8 mm

19.1 in × 17.6 in × 14.1 in*1/ 15.3 in

*2

Copyboard Type

Single-feeder type: 19.3 kg

*1

/ 42.5 lb*1, 20.9 kg*2/ 46.0 lb

Multifeeder type: 19.5 kg*1/ 42.9 lb*1, 21.1 kg*2/ 46.4 lb

ADF Type

Single-feeder type: 23.8 kg

*1

/ 52.4 lb*1, 25.2 kg*2/ 55.4 lb

Multifeeder type: 24.0 kg*1/ 52.8 lb*1, 25.4 kg*2/ 55.9 lb

Copy paper: Keep wrapped, and protect against humidity. Toner: Avoid direct sunlight, and store at 40°C/104°F, 85%

or less.

Table 1-204

*2 *2

1-5

CHAPTER 1 GENERAL DESCRIPTION

5. Default Ratios

Direct

Reduce I

Reduce II

Reduce III

Reduce IV

Enlarge I

Enlarge II

Item

2R2E (Inch/AB-configuration)

1:1.000

1:0.707

1:0816

1:1.154

1:1.414

Table 1-205

3R1E (Inch-configuration)

1:1.000

1:0.707

1:0.786

1:0.860

1:1.414

1-6

6. Copying Speed

CHAPTER 1 GENERAL DESCRIPTION

Copying speed

at Direct

13

12

10

Reproduction ratio

Direct

Reduce I (70.7%)

Reduce II (78.6%)

Reduce IV (86.0%)

Enlarge II (141.4%)

Direct

Reduce I (70.7%)

Reduce III (81.6%)

Enlarge I (115.4%)

Enlarge II (141.4%)

Direct

Reduce I (70.7%)

Reduce III (81.6%)

Enlarge I (115.4%)

Enlarge II (141.4%)

Direct

Reduce I (70.7%)

Reduce II (78.6%)

Reduce III (86.0%)

Enlarge II (141.4%)

Copy size

LTRR

LGL

STMTR

MIN

LGL → LTRR

MARJIN

MAX

A4R

B5R

A5R

A4R → A5R B5R → A5R B5R → A4R

A5R→ A4R

A4R

B5R

A5R

A4R → A5R B5R → A5R B5R → A4R A5R → A4R

LTRR

LGL

STMTR

MIN

LGL → LTRR

MARJIN

MAX

Number of copies

*1

( Multifeeder

)

(Copies / min)

13 (9) 11 (8) 13 (9) 13 (9) 13 (9) 13 (9) 10 (9) 12 (9) 12 (9) 12 (9) 12 (9) 12 (9) 12 (9) 10 (9) 10 (9) 10 (9) 10 (9) 10 (9) 10 (9) 10 (9)

10 m(9)

10 (9)

9 10 (9) 10 (9) 10 (9) 10 (9)

9

Table 1-206

*1. The number of copies starting with the pickup operation that follows the delivery of the

19th copy in a continuous copying job. (See p.5-8)

The specifications are subject to change for product improvement.

1-7

CHAPTER 1 GENERAL DESCRIPTION

B. ADF

Item

Original pickup

Original orientation

Original position

Original separation

Original type

Stack

Original processing mode

Original size detection

Mixed original sizes

Descriptions

Auto pickup/delivery

Face-down

Center reference

Top separation

Single-sided (50 to 128 g/m

2

) A5 (STMT) to A4R (LTRR), LGL Length: 139.7 to 355.6 mm (feeding direction) Width: 139.7 to 215.9 mm

30 sheets (80 g/m

2

or less; about 3 mm in height)

Single-sided original to single-sided copy

Yes (in feeding direction)

No

Original detection

Original feeding speed

Communication with host

Dimensions

Weight

Power source

Maximum power consumption

Operating environment

Yes

446 mm/sec

IPC

Width: 474 mm/ 18.7 in.

(659 mm/ 25.9 in. with the tray open) Depth: 394 mm/ 15.5 in. Height: 74 mm/ 2.9 in. (216 mm/ 8.5 in. with the tray open)

5 kg/ 11 lb (approx.)

24 VDC and 5 VDC (from the host)

40 W or less

Temperature: same as the host Humidity: same as the host

Table 1-207

1-8

*1. The following may not be used as an original:

• Sheet with a staple, clip, or glue.

• Sheet with a cut, hole, or tear.

• Sheet with holes for binding.

• Sheet with a carbon back.

• Sheet with a cut-and-paste piece.

• Sheet with curling, bending, or wrinkling.

The specifications are subject to change for product improvement.

CHAPTER 1 GENERAL DESCRIPTION

1-9

CHAPTER 1 GENERAL DESCRIPTION

III. NAMES OF PARTS

A. External View

1. Copyboard Type

[1] Copyboard cover [2] Static eliminator cleaner [3] Manual feed tray

[6]

[5]

[1]

[2]

[3]

[4]

[4] Right door [5] Cassette [6] Copyboard glass

Figure 1-301

[3]

[2]

[1]

[6]

[1] Copy tray [2] Power cord connector [3] Open/close lever

[4]

[5]

[4] Static eliminator [5] Copy density correction switch [6] Delivery guide plate

Figure 1-302

1-10

2. ADF Type

CHAPTER 1 GENERAL DESCRIPTION

[1]

[5]

[2]

[4]

[1] ADF [2] Manual feed tray [3] Right door

[5]

[4]

[3]

[4] Cassette [5] Copyboard glass

Figure 1-303

[6]

[7]

[2]

[1]

[1] Static eliminator cleaner [2] Delivery guide plate [3] Copy tray

[5] Open/close lever [6] Static eliminator [7] Copy density correction switch

[4] Power cord connector

Figure 1-304

1-11

CHAPTER 1 GENERAL DESCRIPTION

3. ADF

[2]

[3]

[4]

[1]

[1] Original tray [2] Original delivery tray

[3] Slide guide [4] Auxiliary tray

Figure 1-305

1-12

B. Cross Section

1. Body

[1]

[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

CHAPTER 1 GENERAL DESCRIPTION

[28] [27] [26] [25] [24] [23] [22] [21] [20] [19] [18] [17] [29][16] [15]

[1] No. 3 mirror [2] No. 2 mirror [3] No. 1 mirror [4] Scanning lamp [5] Heat exhaust fan [6] Copyboard glass [7] Side blanking lamp [8] Lens [9] Primary charging roller [10] No. 6 mirror

[11] Cartridge [12] No. 4 mirror [13] No. 5 mirror [14] Multifeeder tray [15] Vertical path roller [16] Multifeeder pickup roller [17] Cassette pickup roller [18] Registration roller [19] Developing cylinder [20] Photosensitive drum

Figure 1-306

[21] Transfer roller [22] Feed belt [23] Cassette [24] Fixing upper unit [25] Fixing lower roller [26] Cleaning roller [27] Delivery roller [28] Copy tray [29] Single-feeder pickup roller

1-13

CHAPTER 1 GENERAL DESCRIPTION

2. ADF

[6][5][4][3][2][1]

[13] [12]

[1] Delivery roller [2] Copy tray [3] Pickup roller 2 [4] Pickup roller 1 [5] Copyboard tray [6] Auxiliary tray [7] Guide plate

[11] [9] [8] [7][10]

[8] Separation pad [9] Registration roller [10] Feed belt drive roller [11] Feed belt [12] Feed belt roller [13] Feed belt link slave roller

Figure 1-307

1-14

IV. USING THE MACHINE

A. Control Panel

CHAPTER 1 GENERAL DESCRIPTION

No.

1

2

3

4

[15] [14] [12] [10][11][13]

Name

Copy density adjusting lever

Copy density mode indicator

Default ratio indicator

Paper selection indicator

*1

[5][4][3][2]

Figure 1-401

Description

Adjusts the density of copies manually.

Indicates the selected copy density mode.

Indicates the selected default ratio.

Indicates the selected cassette/ manual feed tray.If there is no paper loaded, it flashes.

[8] [9][7][6][1]

Remarks

5

Jam indicator

6

Count/ratio indicator

Flashes in response to a jam.

• Indicates the number of copies or reproduction ratio.

100 (max.; continuous copying)

• The symbol “%” turns on when indicating a ratio.

7

Clear/stop key

Stops copying or returns copying mode to standard mode.

Standard Mode Ratio: 100% Count: 1 Paper source: cassette Copy density: auto

8

Copy start key

9

Power switch

Starts copying.

Turns on and off the power.

mode

1-15

CHAPTER 1 GENERAL DESCRIPTION

No.

10

Name

Count/zoom set key

Sets the number of copies or a

Description

zoom ratio.

11

Zoom indicator

*2

Turns on when zoom mode is selected.

12

13

Zoom key

*2

Paper selection key

*1

Selects/deselects zoom mode.

Selects the cassette/ manual feed tray.

14

Default ratio key

Selects a default reproduction ratio.

15

Copy density mode selection

Selects copying density mode.

key

Table 1-401

*1. Applies only to a multifeeder model. *2. Applies only to a model equipped with a zoom function.

Remarks

May be between 70% and 141% in 1% increments.

1-16

CHAPTER 1 GENERAL DESCRIPTION

V. ROUTINE MAINTENANCE BY THE USER

Instruct the user to clean the following if images tend to be soiled or copy paper tends to jam

often.

1. Soiled Images

a. Copyboard Glass/Copyboard Cover

Clean the cover with a moist cloth (with water or mild detergent solution); then, dry wipe it.

b. Feeding Belt (ADF type) b.1 Cleaning in Feeder Cleaning Mode

1) Turn on the machine, and hold down the Copy Density Mode Selection key for 4 sec or more.

• The count/ratio indicator will indicate ‘U6’.

Zoom

Figure 1-501

2) Place about 10 sheets of blank copy paper (A4/LTR) on the original tray of the ADF.

3) Press the Copy Start key.

• Copy paper will be fed from the original tray.

• The indicator flashes ‘U6’ while the feeder is being cleaned.

4) Press the Copy Density Mode Selection key to end the mode.

Caution:

• You cannot start feeder cleaning mode while the machine is making copies or if an error

exists.

• The auto power-off mechanism does not operate while feeder cleaning mode is being

executed.

1-17

CHAPTER 1 GENERAL DESCRIPTION

b.2 Cleaning by Hand

1) Wipe the feed belt with a moist cloth (water or mild detergent solution) in the direction of the arrow in the figure; then, dry wipe it.

Figure 1-502

2. If Jams Occur Frequently

a. Static Eliminator

1) Remove the static eliminator cleaner from the machine.

Figure 1-503 (Copyboard type)

1-18

CHAPTER 1 GENERAL DESCRIPTION

Figure 1-504 (ADF type)

2) Pull the open/close lever to open the machine.

3) Using the static eliminator cleaner, clean the static eliminator.

• Brush out the paper lint or the like from the groove of the static eliminator.

Figure 1-505

4) Close the machine as soon as you have finished cleaning. (Work briskly.)

1-19

CHAPTER 1 GENERAL DESCRIPTION

VI. IMAGE FORMATION

A. Outline

The construction of the machine is as follows:

Primary charging roller

Fixing assembly

Scanning lamp

Side blanking lamp (front, rear)

Cleaning blade

Copyboard glass

Fixed focal point lens

Developing blade

Developing cylinder

Photosensitive drum

Transfer charging roller

Static eliminator

Figure 1-601

1-20

CHAPTER 1 GENERAL DESCRIPTION

The machine’s image formation process consists of the following seven steps:

Step 1 Primary charging (AC + negative DC) Step 2 Image exposure Step 3 Development (AC + negative DC) Step 4 Transfer (negative DC) Step 5 Separation (curvature separation + static eliminator; positive DC) Step 6 Fixing Step 7 Drum cleaning

Static latent image formation block

Delivery

1. Primary charging

7. Drum cleaning

6. Fixing

: Flow of copy paper : Rotation of the photosensitive drum

5. Separation

2. Image exposure

3. Development

4. Transfer

Figure 1-602

Manual feed

Registration

Cassette

1-21

CHAPTER 2

BASIC OPERATION

This chapter provides descriptions on basic operations, functions of each operation, relationships between electrical and mechanical systems, and timing at which each associated part is turned on.

Process speed 96 mm/sec

I. BASIC OPERATIONS .................. 2-1

A. Functional Constr uction ........2-1

B. Outline of Electr ical

Circuitry .................................2-2

C. Basic Sequence of

Operations.............................2-3

D. Controlling the Main Motor

(M1) .......................................2-5

E. Inputs to and Outputs from

the DC Controller ..................2-7

CHAPTER 2 BASIC OPERATION

I. BASIC OPERATIONS

A. Functional Construction

The machine consists of four functional blocks: pickup/feeding system, exposure system, im-

age formation system, and control system.

Control system

Control panel

Control circuit

Copy tray

Fixing assembly/ delivery assembly

Exposure system

Original

illuminating block

Primary charging

roller

Drum

cleaning block

Feeding

Copyboard

Optical block

Photosensitive

drum

Transfer/

separation

Cassette

Image formation system

Developing

assembly

Pickup

control block

Manual feed block

Pickup/ feeding system

Figure 2-101

2-1

CHAPTER 2 BASIC OPERATION

B. Outline of Electrical Circuitry

The machine’s major electric mechanisms are controlled by the microprocessor mounted on the DC controller PCB, which reads input signals from sensors and operating keys according to the instructions of the program stored in advance and sends signals used to drive motors, solenoids, lamps, and other loads as needed.

Composite

power supply PCB

Q900

CPU

High-

voltage

circuit

block

Scanning lamp

Fixing heater

Contact

PCB

• Primary charging roller

• Developing cylinder

• Transfer charging roller

• Static eliminator

Sensor

• Scanner home position detection

• Lens home position detection

• Pre-registration roller paper detection

• Delivery paper detection

• Vertical path roller paper detection

• Single-feeder paper detection

DC controller PCB

Q101

CPU

+5V +24V

AE sensor

PCB

Thermistor

• Scanner thermistor

• Fixing thermistor

Control

panel

Power switch

• Pickup clutch solenoid

• Registration clutch solenoid

Solenoid

Side blanking

Scanner/

lens drive motor

Scanner cooling fan

• Lens solenoid

• Multifeeder pickup solenoid

• Cassette pickup solenoid

lamp

Main motor driver PCB

Main

motor

2-2

Sensor/

switch

ADF

ADF load

Figure 2-102

C. Basic Sequence of Operations

• A4R, Direct, 2 Copies, Continuous, Cassette

Copy Start keyPower switch ONON

CHAPTER 2 BASIC OPERATION

STBY INTR AER

Main motor (M1) Scanning lamp (LA1) Scanner Primary AC bias Primary DC bias Developing AC bias Developing DC bias Transfer bias Static eliminator bias Fixing heater (H1)

III I

0.3sec (approx.)

I : Scanner home position detection II : Lens home position detection

SCFW

Forward

SCRV

Reverse

SCFW

SCRV

LSTR

STBY

Figure 2-103

2-3

CHAPTER 2 BASIC OPERATION

STBY (standby)

INTR (initial rotation)

AER (AE rotation)

SCFW (scanner forward)

SCRV (scanner reverse)

LSTR (last rotation)

Period

• From when he power switch is turned on to when the Copy Start key is pressed.

• From when LSTR ends to when the Copy Start key is pressed.

From when the Copy Start key is pressed to when the scanner moves forward.

While the scanner moves forward about 10 cm and then moves it in reverse.

While the scanner is moving forward.

• The distance varies according to the selected copy size and reproduction ratio.

• The forward speed varies according to the selected reproduction ratio.

While the scanner is moving in reverse.

• The reverse speed is about 3.3 as fast as the forward speed used in Direct.

From when SCRV ends to when the main motor stops.

Description

Waits until the Copy Start key is pressed.

Removes residual charges from the photosensitive drum, thereby ensuring a stable drum sensitivity.

Measures the density of the original.

Illuminates the original by the scanning lamp, and the reflected optical image is projected to the photosensitive drum through mirrors and lenses.

Moves the scanner to the home position in preparation for the next copying run.

Neutralizes the drum surface potential as post-processing.

Table 2-101

2-4

CHAPTER 2 BASIC OPERATION

D. Controlling the Main Motor (M1)

1. Outline

Table 2-102 shows the functions of the main motor control circuit, and Figure 2-104 is a block

diagram of the circuit.

Item

Power supply

Drive signal

Moving/drive parts

Control

Error detection

DC

controller

PCB

J103

-6

J203

-3

Description

24 VDC from the composite power supply.

Signal (MMD) from the DC controller PCB.

Photosensitive drum, primary charging roller, developing assembly, transfer charging roller, pickup roller, vertical roller, registration roller, feeding assembly, fixing assembly, delivery roller, heat exhaust fan

Executes on/off control. Executes constant speed rotation control.

Issues ‘E010’.

Table 2-102

+24V

J205

-4

-3

-2

24V

GND

MMD

J901

-1

-2

-3

Phase

control

drive

circuit

Drive current

Clock pulse generator

Main motor

(M1)

J104-1J204

-7

Composite

power supply

PCB

-1

MLOCK

-4

Reference signal

Hall IC output

MMCLK

Main motor drive PCB

Figure 2-104

2-5

CHAPTER 2 BASIC OPERATION

2. Operations

The main motor (M1) is a DC motor with a built-in clock pulse generator, which generates

clock pulses (MMCLK) in relation to the rotation of the motor while the motor is rotating.

The speed control circuit controls the main motor (M1) so that it rotates at a specific speed by

matching the frequency of these clock pulses and that of the reference signals.

When the main motor drive signal (MMD) from the DC controller circuit goes ‘1’, the motor

diver drive circuit turns on, causing the main motor (M1) to rotate at a specific speed.

While the main motor is rotating at a specific speed, the main motor driver PCB keeps sending the constant speed state signal (MLOCK=0) to the DC controller PCB. If the rotation of the motor starts to have fluctuations, the MLOCK signal goes ‘1’.

Related Error Code

E010

While the main motor drive signal is generated, the rotation of the main motor deviates from a specific number for 1 sec or more.

a. Turning On/Off the Main Motor

When the main motor drive signal (MMD) from the DC controller circuit goes ‘1’, the main motor driver turns on to rotate the main motor (M1).

b. Rotating the Main Motor at a Constant Speed

The drive circuit on the motor driver PCB controls the main motor so that the phase of the frequency of the clock pulse signals (MMCLK) occurring when the motor rotates and that of the frequency of the reference signals match. The main motor driver PCB sends the constant speed state signal (MLOCK=0) to the DC controller circuit.

c. Detecting an Error (E010)

If the rotation of the main motor starts to have fluctuations for some reason, the MLOCK signal goes ‘1’. If the signal remains ‘1’ for about 1 sec, the DC controller will find the condition to be a fault in the main motor, and will stop the main motor and, at the same time, indicate ‘E010’ in the display.

2-6

CHAPTER 2 BASIC OPERATION

PS1

PS2

PS3

TH1

TH2

J101-1

-3

-2

J109-11

-10

-9

J102-7

-9

-8

J132-3

-5

-4

J108-4

-3

-5

J102-1

-6

J131-1

-2

SCHP

LHP

DPD

DIG3

PDP

+5V

RPD

+5V

TH1

TH2

DC controller PCB

When the scanner is in the home position, ‘1’. (The light-blocking plate is at PS1, ‘1’.)

When the lens is in the home position, ‘1’. (The light-blocking plate is at PS2, ‘1’.)

When PS3 has detected paper, ‘0’. (The light-blocking plate is at PS3, ‘1’.)

When PS4 has detected paper, ‘1’. (The light-blocking plate is at PS4, ‘1’.)

When Q751 has detected paper, ‘1’. (The light-blocking plate is at PS751, ‘0’.)

When the surface temperature of the fixing heater increases, the voltage decreases. (analog signal)

When the temperature of the scanner increases, the voltage decreases. (analog signal)

Scanner home position sensor

Lens home position sensor

Delivery sensor

Vertical path roller paper sensor

Pre-registration roller paper sensor

Fixing thermistor

Scanner thermistor

PS4

J113-1

-3

-2

SFPD

DIG2

When PS5 has detected paper, ‘0’. (The light-blocking plate is at PS5, ‘1’.)

Single-feeder paper sensor (Single-feeder type only)

PS5

J62

J62J433

Q751

Sensor PCB

E. Inputs to and Outputs from the DC Controller

1. Inputs to the DC Control (1/2)

Figure 2-105

2-7

CHAPTER 2 BASIC OPERATION

2. Inputs to the DC Controller (2/2)

DC controller PCB

AE sensor PCB

Control panel PCB

+24V

SW309

J601

J107-4

J111J301

J111-15

J111-16

-3

-2

-1

+24V

AE AEREF

PWOFF

When the light reflected by the original increases, the voltage increases.

The keys and the LEDs are wired in a matrix in the control panel PCB, and the DC controller turns on or flashes the LEDs and reads key inputs.

2-8

J62

J102-2

-3

-4

-5

DIG1 HEAT0

DIG1 HEAT1

The variation in the resistance of the fixing heater is corrected in three levels based on combinations of 2-bit signals.

Figure 2-106

3. Outputs from the DC Controller (1/2)

DS1

Door switch

Line filter

LF1

(220/240V model only)

Noise filter

NF1

J201-2

-1

CHAPTER 2 BASIC OPERATION

DC controller PCBComposite power supply PCB

Fixing heater

H1

Thermal fuse 2

Scanning lamp

FU1

Thermal fuse 1

Primary charging roller Developing cylinder Transfer charging roller Static eliminator

LA1

M1

Main

motor

FU2

HVT board

J434J16

J207-1

-2

J910-3

-1

voltage

+24V

Transformer

Fixing heater

activation circuit

Scanning lamp

activation circuit

High-

circuit

block

Micro-

processor

J104-2

J103-6 J104-1

HEAT_TRG

Communication with the composite power supply

MMD MLOCK

When ‘0’, the fixing heater turns on.

See p. 2-5.

Main motor driver PCB

M2

Scanner/ lens drive motor

See p. 3-7.

Figure 2-107

2-9

CHAPTER 2 BASIC OPERATION

4. Outputs from the DC Control PCB (2/2)

DC controller PCB

Pickup clutch solenoid

Registration clutch solenoid

Lens solenoid

Multifeeder pickup solenoid (Multifeeder type only)

Cassette pickup solenoid

Scanner cooling fan

SL1

SL2

SL3

SL4

SL5

FM1

J53

J54

J55

J51

J52

J51

J58

J109-4

J109-6

J109-2

J109-8

J132-2

J130-1

-3

-5

-1

-7

-1

-2

+24V

PUSLD*

+24V

RGSLD*

+24V

LNSLD*

+24V

MFSLD*

+24V

CPUSD*

+24V

FM1D*

When ‘0’, the pickup clutch solenoid turns on.

When ‘0’, the registration clutch solenoid turns on.

When ‘0’, the lens solenoid turns on.

When ‘0’, the multifeeder pickup solenoid turns on.

When ‘0’, the cassette pickup solenoid turns on.

When ‘0’, the scanner cooling fan turns on.

Side blanking lamp (rear)

Side blanking lamp (front)

J106-1

SB_LP*

+24V

-2

Figure 2-108

When ‘0’, the blanking lamp turns on.

2-10

5. Inputs to and Outputs from the ADF

Composite power supply PCB

+24V

+5V +5V

+24V

J114-1

-2

REQ

-3

-4

ACK

-5

-6

TXD

-7

-8

-7

-6

-5

-4

-3

-2

-1

RXD

DC controller PCB

See Chapter 8.

To the ADF

-4

-3

-2

-1

To the ADF

J60

J105-6

-5

-4

-3

-2

-1

J202-1

-2

-3

-4

-5

-6

J24

CHAPTER 2 BASIC OPERATION

Figure 2-109

2-11

CHAPTER 3

EXPOSURE SYSTEM

This chapter discusses the principles of operation used for the machine's lens drive unit and scanner drive unit. It also explains the timing at which these drive units are operated, and shows how they may be disassembled/assmbled and adjusted.

I. OPERATIONS ..............................3-1

A. Outline ...................................3-1

B. Varying the Reproduction

Ratio......................................3-2

C. Lens Drive System ................3-3

D. Scanner Drive System ..........3-4

II. EXPOSURE SYSTEM .................3-9

A. Controlling the Scanning

Lamp .....................................3-9

III. DISASSEMBLY/ASSEMBLY ..... 3-12

A. Scanner Dr ive Assembly.... 3-13

B. Lens Dr ive Assembly ......... 3-31

C. Exposure System ............... 3-37

I. OPERATIONS

A. Outline

Table 3-101 shows the major functions of the exposure system.

CHAPTER 3 EXPOSURE SYSTEM

Item

Lamp

Scanning

Scanner position detection

Ratio variation

Lens drive control

Scanner drive control

Protective function

Description

Halogen

By moving the No. 1 mirror mount

By a sensor (scanner home position sensor; PS1)

Main scanning direction:by varying the optical length Sub scanning direction:by varying the speed of the No. 1 mirror mount

Scanner/lens drive motor (M2) Fixed focal point lens unit Mobile No. 4/5 mirror unit

Scanner/lens drive motor (M2) Scanner thermistor (TH2)

By a fuse (blows in response to overheating of the scanning lamp to cut power to the lamp)

• Thermal fuse (FU1; blows at 128°C)

Table 3-101

Copyboard glass

Enlarge Reduce

Fixed focal point lens

Photosensitive

drum

Moves for enlargement/ reduction

No. 4/5 mirror unit

Figure 3-101

3-1

CHAPTER 3 EXPOSURE SYSTEM

B. Varying the Reproduction Ratio

The reproduction ratio in the drum axial direction (main scanning direction) is varied by the lens drive system, and that in the drum peripheral direction (sub scanning direction) is changed by the scanner drive system.

In the lens drive system, the positions of the fixed focal point lens and the No. 4/5 mirror are changed to vary the reproduction ratio.

In the scanner system, the relative speed of the No. 1 mirror mount is made higher (for reduction) or lower (for enlargement) than the drum peripheral speed.

F'

Direct

F

Optical length

Reduction

F

Optical length

Enlargement

F

Optical length

Optical length: L1 < L2, L1 < L3

Figure 3-102

L1

F'

L2

F'

L3

3-2

CHAPTER 3 EXPOSURE SYSTEM

C. Lens Drive System

1. Outline

The lens drive system is driven by the scanner/lens drive motor (M2). When the lens solenoid (SL3) turns on, the switching gear is pushed in the direction of scanner/lens drive motor rotates in reverse direction ( reduction (

) by the work of the gear and the lens cable.

), the lens unit will move in the direction of

At the same time, the No. 4/5 mirror unit operates according to the distance over which the lens unit is moved by the work of the gear and the cam, thereby varying the optical length.

At this time, the blanking lamp also moves in conjunction with the lens to blank out the appropriate front/rear widths to suit the selected reduction ratio.

SL3 SL3 ON OFF

Switching gear

. In this condition, when the

Switching gear

While the lens is moving

Switching gear

Lens cable

Lens home position

Lens home position detection

Lens solenoid drive signal(LNSLD*)

signal(LHP)

DC controller PCB

sensor (PS2)

Top View

Cam

SL3

Enlargement

Lens unit

Lens shift detecting shaft for side blanking lamp

While the scanner is moving

Scanner/lens drive motor (M2)

No. 4/5 mirror unit

Reduction

Figure 3-103

3-3

CHAPTER 3 EXPOSURE SYSTEM

D. Scanner Drive System

1. Outline

The scanner is driven by the scanner/lens drive motor (M2), whose direction of rotation

changes to move the scanner forward or in reverse.

When moving the scanner forward, the speed of rotation of the motor varies according to the selected reproduction ratio on a continuous basis; when moving the scanner in reverse, on the other hand, its speed remains the same regardless of the selected reproduction ratio in normal copying (312mm/sec, about 3.3 as fast as when moving the scanner forward in Direct).

The distance over which the scanner is moved varies according to the length of copy paper and the selected reproduction ratio.

The scanner/lens drive motor dives the lens drive system as well as the scanner.

M2

PS1 Light-blocking plate

Scanner home position signal (SCHP)

Scanner home position sensor (PS1)

J101-1

-2 SC_B*

-4 SC_COM

-5 SC_A*

-6 SC_A

J110-1 SC_COM

-3 SC_B

Q109

Motor driver circuit

DC controller PCB

3-4

Figure 3-104

CHAPTER 3 EXPOSURE SYSTEM

2. Relationship between Scanner Sensor and Signal

Scanner sensor

Signal

Forward Reverse

PS1(scanner home position

Scanner

sensor)

SCHP

Table 3-102

3. Basic Sequence of Operations (scanner)

Power switch

Scanner home position sensor (PS1)

Pre-registration roller paper sensor (Q751)

Scanner

Copy Start key

STBY

III

ONON

INTR

I

SCFW

Forward

Description

• Provides a means of reference for determining forward movement distance.

• Stops the scanner moving in reverse in 0.1 sec.

SCRV

Reverse

SCFW

SCRV

LSTR

STBY

Scanning lamp(LA1)

I : Scanner home position detection II : Lens home position detection

Figure 3-105

The microprocessor on the DC controller PCB controls the forward movement distance of the scanner with reference to the falling edge of the scanner home position signal. The forward movement distance of the scanner varies according to the length of copy paper and reproduction ratio. If the ratio is less than 130%, the scanner is moved forward as if for A4 (297 mm); if it is 130% or more, the scanner is moved forward as if for LTR (279 mm).

For descriptions on how length is detected, see p. 5-10.

3-5

CHAPTER 3 EXPOSURE SYSTEM

4. Controlling the Copying Speed

The machine uses a halogen lamp for scanning, and the heat of the lamp increases the tempera-

ture of the copyboard.

To prevent possible overheating of the copyboard glass, the temperature of the scanner is monitored by a thermistor (TH2); if its reading reaches 37.5°C or higher, the copying speed is reduced to 6 cpm.

If this mechanism turns on during continuous copying, it remains on until the end of the copying job.

At the end of copying, if the reading of the thermistor is 34.5°C or higher, the No. 1 mirror mount is moved forward 105 mm from the home position and stopped, thereby lowering the temperature of the copyboard fast.

Reference:

While the copying speed is controlled to 6 cpm, the speed of the reverse movement of the scanner is reduced to prevent overheating of the copyboard glass. (about 75 mm/sec)

Switching to 6-cpm copying speed

SCRV

Check timing by thermistor (TH2)

Main motor (M1) Pickup clutch solenoid (SL1)

Registration clutch solenoid (SL2)

Scanner

SCFW

SCRV

37.5˚C or higher 34.5˚C or higher

SCFW SCRV SCFW SCRV

I

II

LSTR

STBY

I : When the pre-registration roller paper sensor (Q751) is off, the pickup clutch solenoid is

turned off to prevent overheating of the pickup clutch solenoid (SL1).

II : By the time the Copy Start key is pressed or the power switch is turned off and then on again

next time, the scanner is moved to and stopped at 105 mm forward from the home position.

Figure 3-106

3-6

CHAPTER 3 EXPOSURE SYSTEM

5. Controlling the Scanner/Lens Drive Motor

a. Outline

The scanner/lens drive motor (M2) is a 4-phase stepping motor. The timing at which the drive power (SC-COM) and pulses (SC-A, SCA*, SC-B, SC-B*) are generated is controlled to turn on/ off the scanner/lens drive motor (M2) or to switch the direction of its rotation.

(Q101)

Microprocessor

DC controller PCB

A A* B B*

Current switching signal 1 Current switching signal 2 Current switching signal 3

+24VU

R399

(Q109)

Motor driver circuit

J110

SC-COM SC-COM

SC-A SC-A*

SC-B SC-B*

M2

3-7

CHAPTER 3 EXPOSURE SYSTEM

b. Operations

The microprocessor (Q101) mounted on the DC controller PCB receives instructions from the control panel PCB copying mode settings (e.g., reproduction ratio). In response, it applies drive pulses to the scanner/lens drive motor (M2) through the motor driver circuit.

The scanner motor is a 4-phase stepping motor, and changes the direction and speed of its rotation according to the sequence and frequency of drive pulses (SC-A*through SC-B*).

The motor drive voltage is switched on and off by pulse signals (A through B*) generated by the microprocessor (Q101). Any of these pulse signals is generated when the motor is in operation, while no pulse signal is generated when the motor is at rest.

The current switching signals from 1 to 3 generated by the microprocessor (Q101) are used to control the current flowing to the motor so that it varies according to the state of the scanner and the lens.

Forwarding the

scanner

Current switching signal 1

Current switching signal 2

Current switching signal 3

Starting the lens

0

Moving the lens

0

1

Reversing the

scanner

0

1

c. Detecting Overcurrent for the Scanner/Lens Drive Motor

If overcurrent flows to the scanner/lens drive motor for some reason, the fuse (R339) on the DC controller PCB will blow to cut the power to the motor.

Caution:

The fuse (R339) will not recover once it has blown.

1

3-8

CHAPTER 3 EXPOSURE SYSTEM

(Q101)

Serial communication

VR107

DC controller PCB

Microprocessor

(Q900)

Intensity adjustment signal

PWM_1KHz

Lamp activation signal

LAMP_ON

Activation detection signal

LAMP_DETECT

Composite power supply PCB

9 4 2

7

(HIC001)

Phase

control

circuit

Arcing circuit

Scanning lamp (LA1)

Thermal fuse (FU1)

Activation detection circuit

Rectifying

circuit

Microprocessor

Rectifying

circuit

+

-

+

-

II. EXPOSURE SYSTEM

A. Controlling the Scanning Lamp

1. Outline

Figure 3-201 shows the circuit used to control the scanning lamp, and has the following func-

tions:

• Turning on/off the scanning lamp.

• Controlling the intensity of the scanning lamp.

• Monitoring the state (on/off) of the scanning lamp.

Figure 3-201

3-9

CHAPTER 3 EXPOSURE SYSTEM

2. Operations

a. Turning On/Off the Scanning Lamp

The DC controller PCB and the composite power supply exchange signals in serial communication to control the scanning lamp. According to the scanner lamp active voltage signal, the microprocessor (Q900) on the composite power supply PCB controls the intensity adjustment signal (PWM_1KHz) and the lamp activation signal (LAMP_ON) to turn on/off the scanning lamp (LA1). When LAMP_ON is ‘0’,

The phase control circuit turns on.

The arcing circuit turns on.

The scanning lamp turns on.

When LAMP_ON is ‘1’,

The phase control circuit turns off.

The arcing circuit turns off.

The scanning lamp turns off.

3-10

CHAPTER 3 EXPOSURE SYSTEM

b. Controlling the Intensity of the Scanning Lamp

The intensity of the lamp is controlled by the scanning lamp active voltage signal sent by the

DC controller PCB in serial.

The microprocessor (Q900) on the composite power supply PCB sends the intensity adjustment signal (PWM_1KHz) in response to the scanning lamp active voltage signal. In turn, the phase control circuit (HIC 001) controls the voltage supplied to the scanning lamp.

The PWM_1KHz signal varies according to the setting of VR107 mounted on the DC controller PCB between 10% and 90% in terms of pulse duty ratio or between 50.5 and 80 V for the 120 V model (between 85.7 and 145.8 V for the 220/240 V model) in terms of actual voltage by way of phase control.

However, the intensity remains a specific value for AE exposure so that it is 56 V for the 120 V model (108.5 V for the 220/240 V model) in terms of actual voltage.

t [msec]

1

1k

ON

1kHz

1

OFF

[msec]

<PWM_1KHz signal>

Pulse duty= t/ × 100 [%]

Figure 3-202

c. Monitoring the Activation of the Scanning Lamp

The activation detection signal (LAMP_DETECT) is sent to the microprocessor (Q900) on the composite power supply PCB as long as the scanning lamp remains on.

The composite power supply PCB sends the lamp activation signal to the DC controller PCB in serial by way of monitoring the activation of the scanning lamp (LA1).

Related Error Code

E220

• The lamp activation detection signal is not detected for 1 sec or more although the scanning lamp activation signal has been sent.

• The lamp activation detection signal has been detected for 1 sec or more although the scanning lamp activation signal is not sent.

If an error has been detected, the power switch will be turned off after indicating an error code

for 2 sec.

3-11

CHAPTER 3 EXPOSURE SYSTEM

III. DISASSEMBLY/ASSEMBLY

As needed, disassemble/assemble the machine with the following in mind:

!

Before starting the work, turn off the power switch and disconnect the power plug for

1. safety.

2. Unless otherwise instructed, assemble the parts by reversing the steps used to disassemble it.

3. Identify the screws by type (length, diameter) and location.

4. Use the washers where necessary. (The screws used to mount the grounding wire and Varistors come with a washer to ensure electrical continuity.)

5. As necessary, cut the harness band.

6. As a rule, do not operate the machine with any of its part removed.

7. A few of the screws used are special screws (with wider thread intervals). Do not use any screws indiscriminately.

3-12

A. Scanner Drive Assembly

1. Removing the Scanner/Lens Drive Motor

1) Remove the front lower cover.

(See Chapter 7.III.A.2.“Removing the Front Lower Cover.”)

2) Remove the copyboard glass.

(See Chapter 7.III.C.1.“Removing the Copyboard Glass.”)

3) Remove the four screws [1], and detach

the lens cover [2].

CHAPTER 3 EXPOSURE SYSTEM

4) Disconnect the connector (J110) [3] from

the DC controller PCB.

[1]

[2]

Figure 3-301

[3]

Figure 3-302

3-13

CHAPTER 3 EXPOSURE SYSTEM

5) Open the machine’s top unit farther, and hold it in position using the handle (about 30 mm in diameter) of a screwdriver.

6) Remove the machine’s two fixing screws [4] from the scanner/lens drive motor [5].

[4]

Figure 3-303

[5]

[4]

Figure 3-304

3-14

7) Free the top unit (by removing the screwdriver), and close the top unit.

8) Remove the E-ring [6]; then, lift the cable drive pulley [7] slightly, and detach the scanner/lens drive motor [5].

CHAPTER 3 EXPOSURE SYSTEM

[6]

Lift.

[5]

Figure 3-305

[7]

3-15

CHAPTER 3 EXPOSURE SYSTEM

2. Outline of the Scanner Drive Cable

Wind 1.5 times. (black cable) Wind 7.5 times. (silver-colored cable)

Figure 3-306

3-16

3. Routing the Scanner Drive Cable

a. Before Starting the Work

Prepare the following:

• Mirror positioning tool

• Cable clip

• Adhesive tape

1) Set the mirror positioning tool as shown.

CHAPTER 3 EXPOSURE SYSTEM

2) Prepare about five strips of adhesive tape (each one about 20 × 50 mm).

3) Remove the copyboard glass. (See Chapter 7.III.C.1.“Removing the Copyboard Glass.”)

4) Disconnect the connectors (J101, J131) [1] from the DC controller PCB.

Figure 3-307

[1]

Figure 3-308

3-17

CHAPTER 3 EXPOSURE SYSTEM

5) If the machine is equipped with an ADF, free the hook [2], and disconnect the two relay connectors [3] from the left upper stay [4].

[2]

[3]

[2]

[4]

6) Remove the three screws [5], and detach the left upper stay [4].

[3]

Figure 3-309

[5]

[4]

[2]

3-18

Figure 3-310

[6]

[7]

7) Remove the four screws [6], and detach the lens cover [7].

CHAPTER 3 EXPOSURE SYSTEM

Figure 3-311

3-19

CHAPTER 3 EXPOSURE SYSTEM

b. Routing the Reversing Cable

1) Wind the reversing cables (silver-colored) [2] on the cable drive pulley [1] 7.5 times with the longer end on top; then, secure it in position with a cable clip [3].

[1]

Longer end

[3]

[2]

Shorter end

Face with a marking

Figure 3-312

[3]

[1]

Top View

3-20

Figure 3-313

[7]

[6]

2) Put the cable drive pulley [1] into the shaft [4], and secure it in position with an Ering [5]. When putting the cable drive pulley into the shaft, be sure that the hook is at the front.

CHAPTER 3 EXPOSURE SYSTEM

[5]

Hook

[1]

(front)

[4]

Figure 3-314

3) Hook the shorter end [6] on the pulley [7].

Figure 3-315

3-21

CHAPTER 3 EXPOSURE SYSTEM

4) Lead the shorter end [6] under the No. 1 mirror mount [8] and the No. 2/3 mirror mount [9]; then, hook it on the left rear pulley [10] and the pulley [11] of the No. 2/3 mirror mount.

5) After fitting the shorter end [6] on the cable hook [12], secure its end with adhesive tape [13]. Be sure that the secured end of the cable is found where the hole in the left side plate and the tip of the cable matches.

[10]

[11]

Figure 3-316

[13]

[6]

[9]

[8]

[6]

[12]

6) Lead the longer end [14] along the cable drive pulley, and hook it on the pulley [15] on the right front side.

3-22

Figure 3-317

[14]

[15]

Figure 3-318

CHAPTER 3 EXPOSURE SYSTEM

7) Lead the longer end [14] under the No. 1 mirror mount [8] and the No. 2/3 mirror mount [9]; then, hook it on the pulley [16] on the left front side and the pulley [17] of the No. 2/3 mirror mount.

8) Hook the longer end [14] on the cable hook [18]; then, secure its end to the left side with adhesive tape [19]. Be sure that the secured end of the cable is found where the hole in the left side plate and the tip of the cable matches.

[8]

[17]

[14]

Figure 3-319

[18]

[19]

[16]

[9]

[14]

Figure 3-320

3-23

CHAPTER 3 EXPOSURE SYSTEM

c. Routing the Forwarding Cable

1) Fit the longer end forwarding cable (black) [2] on the top hook of the cable drive pulley [1], and wind it 1.5 times. Then, secure the shorter end [3] as shown with adhesive tape [4].

2) Lead the longer end [5] along the cable drive pulley [1] as shown, and hook it on the pulley [6] on the right front side.

[4] [3]

Face without a marking

[2]

[1]

Figure 3-321

[5][1]

3) Lead the longer end [5] under the No. 1 mirror mount [7]; then, hook it on the pulley [8] of the No. 2/3 mirror mount, and lead it between the No. 1 mirror mount [7] and the scanning lamp [9].

[5]

Figure 3-322

[7]

Figure 3-323

[6]

[8]

[9]

3-24

[11]

[3]

[7]

[9]

[3]

[12]

4) Hook the end of the longer end [5] on the hole [10] on the right side.

5) Free the shorter end [3], and hook it on the pulley [11] on the right rear side.

CHAPTER 3 EXPOSURE SYSTEM

[10]

[5]

Figure 3-324

Figure 3-325

6) Lead the shorter end [3] under the No. 1 mirror mount [7], and hook it on the pulley [12] of the No. 2/3 mirror mount as shown; then, lead it between the No. 1 mirror mount [7] and the scanning lamp [9].

Figure 3-326

3-25

CHAPTER 3 EXPOSURE SYSTEM

7) Hook the end of the shorter end [3] on the hole [13] on the right side.

8) Free the shorter end [3] and the longer end [5] (reversing cable), and connect both with a spring [14]; then, fit the stopper [15].

[3] [13]

Figure 3-327

[15]

[14]

[3]

[5]

Figure 3-328

3-26

9) Detach the pulley clip [16] from the cable drive pulley [1].

CHAPTER 3 EXPOSURE SYSTEM

[1] [16]

Figure 3-329

3-27

CHAPTER 3 EXPOSURE SYSTEM

d. Positioning the No. 1 Mirror Mount

1) Fix the rear and the front of the No. 1 mirror mount [1] temporarily to the metal fixing [2] of the forwarding cable.

[1]

[2]

Figure 3-330 (rear)

[2]

[1]

Figure 3-331 (front)

3-28

CHAPTER 3 EXPOSURE SYSTEM

[3]

2) Turn the cable drive pulley [4] so that the three shafts [3] of the mirror positioning tool for rear and front is as shown.

[3]

[4]

[3]

Figure 3-332 (rear)

Figure 3-333 (front)

3-29

CHAPTER 3 EXPOSURE SYSTEM

3) While keeping the condition of step 2), tighten the positioning screw on the rear and front of the No. 1 mirror mount [1].

[1]

Figure 3-334 (rear)

[1]

Figure 3-335 (front)

3-30

B. Lens Drive Assembly

1. Removing the Lens Cable

1) Turn on the power; when the lens has moved to the Direct position, disconnect the power plug.

2) Remove the copyboard glass. (See Chapter 7.III.C.1.“Removing the Copyboard Glass.”)

3) Remove the main drive assembly. (See Chapter 7.III.D.2.“Removing the Main Drive Assembly.”)

4) Remove the four screws [1], and detach the lens cover [2].

CHAPTER 3 EXPOSURE SYSTEM

[1]

[2]

Figure 3-336

3-31

CHAPTER 3 EXPOSURE SYSTEM

5) Mark the position of the lens cable fixing plate [3] and the lens mount [4] with a scriber.

Caution:

When routing the lens cable, be sure to refer to the marking made with a scriber.

[3]

Marking

6) Disengage the lever [5] of the No. 4/5 mirror mount and the gear [6].

[4]

Figure 3-337

[6]

[5]

Figure 3-338

3-32

CHAPTER 3 EXPOSURE SYSTEM

7) Remove the screw [7], and detach the cam gear [6] and the cable retainer [8].

8) Holding the middle of the No. 1 mirror mount [9], move it to the center of the machine.

[7]

[6]

[8]

Figure 3-339

[9]

Caution:

Do not hold the reflecting plate.

9) Remove the spring [10].

Figure 3-340

[10]

Figure 3-341

3-33

CHAPTER 3 EXPOSURE SYSTEM

10) Remove the screw [11], and detach the lens cable fixing plate [12].

11) Free the lens cable [13] from the lens cable fixing plate [12]; then, detach the lens cable from the machine.

[11]

[12]

Figure 3-342

[13]

[12]

3-34

Figure 3-343

[2]

[1]

2. Routing the Lens Cable

1) After routing the lens cable, keep the lever [1] of the No. 4/5 mirror mount disengaged from the cam gear [2] (so that the lever will not come into contact when the cam gear rotates).

CHAPTER 3 EXPOSURE SYSTEM

2) While keeping the condition in step 1), turn on the power; when the No. 1 mirror mount and the lens stopped moving, turn off the power.

• The lens will move to the Direct posi-

tion.

3) Check to make sure that the tip of the lever [1] of the No. 4/5 mirror mount and the marking [3] on the top face of the cam gear [2] match; then, engage the lever [1] and the cam gear [2].

Figure 3-344

[2]

[3]

[1]

Figure 3-345

3-35

CHAPTER 3 EXPOSURE SYSTEM

4) If the tip of the lever [1] and the marking on the cam gear [2] do not match, remove the fixing screw [4] of the cam gear [2] and detach the cam gear; then, mount the cam gear once again so that the marking on it and the tip of the lever match.

[4]

[2]

[1]

Figure 3-346

3-36

C. Exposure System

1. Removing the Scanning Lamp

1) Disconnect the power plug.

2) Remove the copyboard glass. (See Chapter 7.III.C.1. “Removing the Copyboard Glass.”)

3) Holding the middle of the No. 1 mirror mount [1], move the No. 1 mirror mount [1] to the right by about 5 cm.

Cauiton:

Do not hold the reflecting plate.

CHAPTER 3 EXPOSURE SYSTEM

[1]

4) Free the harness [3] from the guide [2]; then, remove the screw [4], and detach the reflecting plate [5].

Figure 3-347

[4]

[5]

[3]

[2]

Figure 3-348

3-37

CHAPTER 3 EXPOSURE SYSTEM

5) While pushing the electrode mount [6] found at the rear of the machine in the direction of the arrow, detach the scanning lamp [7].

Caution:

1. Do not start the work if the scanning lamp is hot.

2. Do not leave fingerprints on the surface of the scanning lamp.

3. If the surface of the scanning lamp is soiled, dry wipe it.

[6]

[7]

Figure 3-349

3-38

Logo mark

Scanning lamp

45 (approx.)

(mirror mount moving in reverse)

(front)

2. Points to Note When Mounting the Lamp

When mounting the scanning lamp, be sure that the logo mark (or the name of the manufacturer) is toward the front. Further, be sure that the protrusion near the middle of the lamp is as shown.

Caution:

• Do not touch the lamp portion.

• If you have replaced the scanning lamp, be sure to perform intensity adjustment (p. 11-42) and AE adjustment (p. 11-43).

CHAPTER 3 EXPOSURE SYSTEM

Figure 3-350

3-39

CHAPTER 3 EXPOSURE SYSTEM

3. Removing the Thermal Fuse

1) Disconnect the power plug.

2) Remove the copyboard glass. (See Chapter 7.III.C.1.“Removing the Copyboard Glass.”)

3) Remove the two screws [1], and detach the thermal fuse [2].

[2]

[1]

Figure 3-351

4. Points to Note When Mounting the

Fuse

When mounting the thermal fuse, be sure

that the thermal fuse is oriented as shown.

Make sure that the fuse is in contact with

the reflecting plate.

Reflecting plate

(front)

Thermal fuse

Figure 3-352

3-40

5. Removing the Thermistor Unit

1) Remove the top cover. (See Chapter 7.III.A.1. “Removing the Top Cover.”)

2) Disconnect the connector (J131) [1] from the DC controller PCB; remove the screw [2], and detach the thermistor unit [3].

CHAPTER 3 EXPOSURE SYSTEM

[3]

[1]

[2]

Figure 3-353

3-41

CHAPTER 4

IMAGE FORMATION SYSTEM

This chapter discusses the principles of how images are formed. It also explains the timing at which the various units involved in image formation are operated, and shows how they may be disassembled/assembled and adjusted.

I. IMAGE FORMATION SYSTEM ...4-1

A. Outline ...................................4-1

B. Timing Chart for the Image

Formation System .................4-3

C. Controlling the Pr imar y

Charging Roller Bias .............4-4

D. Controlling the Transfer

Roller Bias.............................4-8

E. Controlling the Developing/

Separation Static Eliminator

Bias .................................... 4-11

F. Measuring the Density of

Originals ............................. 4-16

G. Controlling the Side Blanking

Mechanism......................... 4-21

II. DISASSEMBLY/ASSEMBLY ..... 4-22

A. Cartridge ............................ 4-23

B. Transfer Charging

Assembly............................ 4-25

C. Blank Exposure .................. 4-26

CHAPTER 4 IMAGE FORMATION SYSTEM

I. IMAGE FORMATION SYSTEM

A. Outline

The major functions of the image formation system are as follows:

Item

Controlling the primary charging roller bias

Transfer roller bias control

Developing/separation static eliminator bias control

Density control

Blanking control

Description

AC constant current control, on/off control DC constant voltage control, on/off control DC voltage level control

DC constant voltage control, on/off control DC constant current control (ATVC, cleaning bias) Voltage level control Polarity switching

DC constant voltage control, on/off control AC constant voltage control, on/off control DC voltage level control

Developing DC bias control

Side blanking lamp

Table 4-101

4-1

CHAPTER 4 IMAGE FORMATION SYSTEM

Copyboard glass

Scanning lamp

AE sensor

Lens

Side blanking lamp

Q101

Microprocessor

DC controller PCB

Primary charging roller

Static eliminator

Lamp regulator

block

Q900

Microprocessor

Figure 4-101

Developing cylinder

Photo-

sensitive

drum

Drum cartridge

Transfer roller

High-voltage

circuit block

Composite power supply PCB

4-2

CHAPTER 4 IMAGE FORMATION SYSTEM

B. Timing Chart for the Image Formation System

Basic Sequence of Operations (Direct, 2 copies, continuous)

Copy Start key

ON

Main motor (M1) Scanning lamp (LA1) Scanner Primary AC bias Primary DC bias Developing AC bias Developing DC bias Transfer bias Transfer cleaning bias

Transfer reference bias (ATVC)

Static eliminator bias Pre-registration roller

paper sensor (Q751)

STBY

INTR

-400V

-500V

SCFW

forward

-625V

3200V

SCFWSCRV

Reverse

0.5sec.(approx.)

0.6sec.(approx.)

SCRV

0.6sec.(approx.)

LSTR

STBY

Figure 4-102

4-3

CHAPTER 4 IMAGE FORMATION SYSTEM

C. Controlling the Primary Charging Roller Bias

1. Outline

The circuit shown in Figure 4-103 is used to control the voltage applied to the primary charging

roller, and has the following functions:

• Turning on and off the DC/AC bias

• Controlling the DC bias to a specific voltage

• Controlling the AC bias to a specific voltage

• Switching the level of the DC bias

Both DC bias and AC bias are applied to the primary charging roller so as to ensure that the surface potential of the photosensitive drum will be uniform. The level of the DC bias is switched between when forming copy images and when not forming copy images.

Reference:

DC component: -400 V (non-image area)/-625 V (image area) AC component: 2000 Vpp to 3000 Vpp (885µA)

4-4

Main transformer

CHAPTER 4 IMAGE FORMATION SYSTEM

T101

Voltage

separation

circuit

PDC_PWM

DC bias control signal

Microprocessor (Q900)

PDC_S

DC voltage monitor signal

High-voltage

T508

Amplifier

PAC_S

AC component current monitor signal

AC bias output signal

transformer for primary charging

Photosensitive

PAC_OUT

Primary charging roller

drum

-5

J203

PR_DC_ON

J103

-4

Microprocessor (Q101)

Figure 4-103

Composite power supply PCB

Serial communication

DC controller PCB

4-5

CHAPTER 4 IMAGE FORMATION SYSTEM

2. Operations

a. Turning On and Off the DC Bias

The DC bias applied to the primary charging roller is turned on or off by the serial communication signal and the primary charging bias ON signal (PR_DC_ON) from the DC controller PCB.

When the Copy Start key is pressed, the DC bias ON signal (serial) and the primary charging bias ON signal (PR_DC_ON) are sent. The microprocessor (Q900) on the composite power supply PCB generates the DC bias control signal (PDC_PWM) based on the combination of the serial signal and the PR_DC_ON signal, applying a DC bias to the primary charging roller.

PR_DC_ON

(J103-4)

0

1

DC bias ON (image area) DC bias ON (non-image area) DC bias OFF

DC bias ON signal

(8-bit signal communication)

bit0 bit1

1–

10

00

Table 4-102 Relationship between DC Bias Output and Signal

b. Turning On and Off the AC Bias

The AC bias applied to the primary charging roller is turned on and off by the serial communication signal from the DC controller PCB.

When the AC bias ON signal arrives from the DC controller PCB, the microprocessor (Q900) on the composite power supply PCB generates the AC bias output signal (PAC_OUT), thereby applying an AC bias to the primary charging roller.

c. Controlling the DC/AC Bias to a Specific Voltage/Current

The DC bias and the AC bias applied to the primary charging roller are controlled by the microprocessor (Q900) on the composite power supply PCB so that they remain a specific level.

When a DC/AC bias is generated, the microprocessor (Q900) on the composite power supply PCB detects the DC voltage monitor signal (PDC_S) and the AC component current monitor signal (PAC_S), compares their levels against the reference levels, and varies the DC bias control signal (PDC_PWM) and the AC bias output signal (PAC_OUT) according to the differences so as to ensure that they remain specific levels.

Reference:

The DC bias control signal varies its pulse duty ratio while the AC bias output signal varies its amplitude to change the level of the DC/AC bias.

4-6

Canon PC800S, PC900S, PC960, PC981, PC940 User Manual

CONTENTS

CHAPTER 1

I. FEATURES

II. SPECIFICATIONS

III. NAMES OF PARTS

IV. USING THE MACHINE

V. ROUTINE MAINTENANCE BY THE USER

VI. IMAGE FORMATION

CHAPTER 2

I. BASIC OPERATIONS

CHAPTER 3

I. OPERATIONS

II. EXPOSURE SYSTEM

III. DISASSEMBLY/ASSEMBLY

CHAPTER 4

I. IMAGE FORMATION SYSTEM