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Canon MF4690 Service Manual - Page 62

Controlling the Laser Activation Timing, 3 Controlling the Intensity of Laser Light

UPC - 013803076820

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Chapter 5 5.2 Controlling the Laser Activation Timing 5.2.1 Laser ON / OFF Control 0016-1834 This is the control where the laser driver turns on / off the laser diode (LD) based on the laser control signal sent from the DCNT board. The following is the circuit diagram for laser control. SCNT board DCNT board Laser driver circuit +5V J902-2 J931-8 -1 /BDI -9 BD sensor /BD J901-6 IC902 CPU VDO -3 /VDO -2 PD Photo diode) LD Laser diode) -5 CNT1 -5 -4 CNT0 -6 Laser driver IC Comparator Logic circuit Sample hold circuit C803 -8 VDO -3 -7 /VDO -2 Drive circuit F-5-2 The DCNT board sends the video signal (VDO, /VDO) for image formation and the laser control signal (CNT0, CNT1) for switching the laser operation mode to the logic circuit in the laser driver IC. The laser driver IC performs laser control based on the combination of CNT0 and CNT1 signals. The following chart shows the combination of the laser control signals (CNT0, CNT1). T-5-1 Operation mode Discharge mode Print mode LD APC mode LD forced OFF mode CNT0 CNT1 Remarks Discharge of C803 L L Use at normal printing H L Use at LD APC L H Use at masking image H H 5.3 Controlling the Intensity of Laser Light 5.3.1 Auto Photoelectric Current Control (APC) 0016-1835 This is the control to emit the definite level of laser diode. There are initial APC during initial rotation (note 1) and line space APC during printing (note 2), which are performed in the same procedure. The following is its procedure. 1) When the laser control signal (CNT0, CNT1) turned into LD APC mode, the laser driver emits LD forcedly. 2) After being detected with the photodiode (PD), the LD emission level as current is converted to the one as voltage and compared with the reference voltage (the voltage equivalent to the target laser level). 3) The laser driver controls the laser current until it reaches the voltage of LD target level. 4) When the laser control signal turns into LD forced OFF mode, LD is forcedly off and the laser driver converts the adjusted laser level to the voltage of the condenser and keeps it. Note 1. Initial APC APC during initial rotation. Laser level is adjusted by APC. Note 2. Line space APC APC during printing. Adjustment of laser level for one line is performed before writing one line. 5-2

Section	Page
Chapter 1 Introduction	15
1.1 Product Specifications	19
1.1.1 Names of Parts	19
1.1.1.1 External View	19
1.1.1.2 Section View (Host Machine)	21
1.1.1.3 Section View (ADF)	21
1.1.1.4 Control panel	22
1.1.2 Safety	24
1.1.2.1 Safety of the Host Machine's Laser Mechanism	24
1.1.2.2 CDRH Regulations	24
1.1.2.3 Handling of the Laser Assembly	24
1.1.2.4 Safety of the Toner	24
1.1.2.5 Fire Attention	24
1.1.2.6 Points no Note when Replacing / Disposing the Lithium Battery	25
1.1.3 Product Specifications	25
1.1.3.1 Host Machine Specifications	25
1.1.3.2 ADF Specifications	26
1.1.3.3 FAX Specifications	26
1.1.4 Function List	27
1.1.4.1 Scanning Range	27
1.1.4.2 Recording Range (Copy)	28
1.1.4.3 Recording Range (Reception)	28
1.1.4.4 Recording Range (Printer)	29
1.1.4.5 Operation Environment of the Printer Driver	29
1.1.4.6 Network Specifications	29
1.1.4.7 SEND Specifications	30
Chapter 2 Basic Operation	31
2.1 Construction	35
2.1.1 Function Configuration	35
2.2 Basic Sequence	35
2.2.1 Basic Operation Sequence	35
Chapter 3 Original Exposure System	37
3.1 Basic Constraction	41
3.1.1 Specifications / Control / Function List	41
3.1.2 Major Components	41
3.2 Various Control	43
3.2.1 Dirt Sensor Control	43
3.2.1.1 Outline	43
3.3 Parts Replacement Procedure	45
3.3.1 Scanner Unit	45
3.3.1.1 Preparation for Removing the Control Panel Assembly	45
3.3.1.2 Removing the Control Panel Assembly	45
3.3.2 Book Motor	45
3.3.2.1 Preparation for Removing the Flat Bed Motor	45
3.3.2.2 Removing the Flat Bed Motor	45
3.3.3 Contact Sensor	46
3.3.3.1 Removing the Contact Sensor	46
Chapter 4 Original Feeding System	49
4.1 Basic Operation	53
4.1.1 Basic Operation	53
4.1.2 Original Detection	54
4.2 Detection Jams	54
4.2.1 Jam Detection	54
4.3 ADF	55
4.3.1 Pick-up Roller	55
4.3.1.1 Removing the ADF Pickup Roller	55
4.3.2 ADF Motor	55
4.3.2.1 Preparation for Removing the ADF Motor	55
4.3.2.2 Removing the ADF Motor	55
4.3.3 Separation Pad	56
4.3.3.1 Removing the Separation Pad	56
Chapter 5 Laser Exposure	57
5.1 Overview/Configuration	61
5.1.1 Overview	61
5.2 Controlling the Laser Activation Timing	62
5.2.1 Laser ON / OFF Control	62
5.3 Controlling the Intensity of Laser Light	62
5.3.1 Auto Photoelectric Current Control (APC)	62
5.4 Controlling the Laser Scanner Motor	63
5.4.1 Overview	63
5.4.2 Scanner Motor Speed Control	63
5.4.3 Detection of Fault of the Scanner Motor	63
5.5 Parts Replacement Procedure	64
5.5.1 Laser/Scanner Unit	64
5.5.1.1 Preparation for Removing the Laser Scanner Unit	64
5.5.1.2 Removing the Laser Scanner Unit	64
Chapter 6 Image Formation	65
6.1 Overview/Configuration	69
6.1.1 Configuration	69
6.1.2 Print Process	69
6.2 Driving and Controlling the High-Voltage System	71
6.2.1 Generation of Transfer Charging Bias	71
6.3 Toner Cartridge	71
6.3.1 Toner Level Detection	71
6.4 Parts Replacement Procedure	72
6.4.1 Transfer Charging Roller	72
6.4.1.1 Removing the Transfer Charging Roller	72
Chapter 7 Pickup and Feed System	73
7.1 Overview/Configuration	77
7.1.1 Overview	77
7.2 Other Control	77
7.2.1 Overview	77
7.3 Detection Jams	79
7.3.1 Jam Detection Outline	79
7.3.1.1 Overview	79
7.3.2 Delay Jams	79
7.3.2.1 Pickup Delay Jam	79
7.3.2.2 Delivery Delay Jam	79
7.3.3 Stationary Jams	79
7.3.3.1 Pickup Stationary Jam	79
7.3.3.2 Delivery Stationary Jam	79
7.3.4 Other Jams	79
7.3.4.1 Door Open Jam	79
7.3.4.2 Wrapping Jam	79
7.3.4.3 Residual Jam at Startup	80
7.4 Duplex Unit	81
7.4.1 Overview	81
7.5 Parts Replacement Procedure	82
7.5.1 Main Motor	82
7.5.1.1 Preparation for Removing Main Motor	82
7.5.1.2 Removing Main Motor	82
7.5.2 Separation Pad	82
7.5.2.1 Preparation for Removing Separation Pad	82
7.5.2.2 Removing Separation Pad	82
7.5.3 Pickup Roller	82
7.5.3.1 Removing Pickup Roller	82
Chapter 8 Fixing System	83
8.1 Overview/Configuration	87
8.1.1 Specification/Control/Function List	87
8.1.2 Overview	87
8.2 Various Control Mechanisms	89
8.2.1 Controlling the Temperature of the Fixing Unit	89
8.2.1.1 Fixing Temperature Control	89
8.3 Protection Function	90
8.3.1 Protection Function	90
8.4 Parts Replacement Procedure	92
8.4.1 Fixing Unit	92
8.4.1.1 Preparation for Removing Fixing Assembly	92
8.4.1.2 Removing Fixing Assembly	92
8.4.2 Fixing Film Unit	92
8.4.2.1 Preparation for Removing Fixing Film Unit	92
8.4.2.2 Removing Fixing Film Unit	92
Chapter 9 External and Controls	95
9.1 Control Panel	99
9.1.1 Outline	99
9.2 Power Supply	99
9.2.1 Protection Function	99
9.2.1.1 Protecting Function	99
9.3 Parts Replacement Procedure	100
9.3.1 Front Cover	100
9.3.1.1 Removing the Front Cover	100
9.3.2 Rear Cover	100
9.3.2.1 Preparation for Removing the Rear Cover	100
9.3.2.2 Removing the Rear Cover	100
9.3.3 Right Cover	100
9.3.3.1 Removing the Right Cover	100
9.3.4 Left Cover	100
9.3.4.1 Removing the Left Cover	100
9.3.5 Upper Cover	101
9.3.5.1 Preparation for Removing the Upper Cover	101
9.3.5.2 Removing the Upper Cover	101
9.3.6 Cartridge Cover	101
9.3.6.1 Preparation for Removing the Printer Cover	101
9.3.6.2 Removing the Printer Cover	101
9.3.7 Operation Panel Unit	102
9.3.7.1 Removing the Control Panel Unit	102
9.3.8 SCNT Board	102
9.3.8.1 Preparation for Removing the SCNT Board	102
9.3.8.2 Removing the SCNT Board	102
9.3.8.3 Actions At Replacing the SCNT Board	102
9.3.9 DCNT Board	102
9.3.9.1 Preparation for Removing the DCNT Board	102
9.3.9.2 Removing the DCNT Board	102
9.3.10 Analog Processor PCB	104
9.3.10.1 Preparation for Removing the Analog processor PCB	104
9.3.10.2 Removing the Analog processor PCB	104
9.3.11 NCU Board	104
9.3.11.1 Preparation for Removing the NCU Board	104
9.3.11.2 Removing the NCU Board	104
9.3.12 Power Supply PCB	104
9.3.12.1 Preparation for Removing the Power Supply Board	104
9.3.12.2 Removing the Power Supply Board	104
9.3.13 High-voitage Power Supply PCB	104
9.3.13.1 Preparation for Removing the High Voltage Power Supply Board	104
9.3.13.2 Removing the High Voltage Power Supply Board	104
9.3.14 Motor Driver PCB	105
9.3.14.1 Preparation for Removing the Motor driver PCB	105
9.3.14.2 Removing the Motor driver PCB	105
Chapter 10 Maintenance and Inspection	107
10.1 Periodically Replaced Parts	111
10.1.1 Periodically Replaced Parts	111
10.2 Consumables	111
10.2.1 Consumable	111
10.3 Periodical Service	111
10.3.1 Periodically Service Items	111
10.4 Cleaning	111
10.4.1 Cleaning Items	111
10.4.2 Cleaning Method (External Covers)	111
10.4.3 Cleaning Method (Reader Unit)	112
10.4.4 Cleaning Method (Pressure Roller)	112
Chapter 11 Measurement and Adjustments	113
11.1 Scanning System	117
11.1.1 Procedure after Replacing the CIS	117
11.1.2 Procedure after Replacing the Copyboard Glass	117
11.2 Electrical Adjustments	117
11.2.1 Procedure after Replacing the SCNT board	117
Chapter 12 Correcting Faulty Images	119
12.1 Outline of Electrical Components	123
12.1.1 Clutch/Solenoid/Motor/Fan	123
12.1.1.1 List of Solenoids/Motors	123
12.1.2 Sensor	124
12.1.2.1 List of Sensors	124
12.1.3 PCBs	125
12.1.3.1 List of PCBs	125
Chapter 13 Error Code	127
13.1 Error Code	131
13.1.1 List of Error Codes	131
13.2 Fax Error Codes	133
13.2.1 Outline	133
13.2.1.1 Error Code Outline	133
13.2.2 User Error Code	133
13.2.2.1 User Error Code	133
13.2.3 Service Error Code	133
13.2.3.1 Service Error Code	133
Chapter 14 Service Mode	135
14.1 Outline	141
14.1.1 Outline of Service Mode	141
14.1.2 Using the Mode	142
14.2 Default Settings	142
14.2.1 Service Mode Menus	142
14.3 Service Soft Switch Settings (SSSW)	146
14.3.1 Outline	146
14.3.1.1 Bit Switch Composition	146
14.3.2 SSSW-SW01:	147
14.3.2.1 List of Functions	147
14.3.2.2 Detailed Discussions of Bit 0	147
14.3.3 SSSW-SW03	147
14.3.3.1 List of Functions	147
14.3.3.2 Detailed Discussions of Bit 7	147
14.3.4 SSSW-SW04	148
14.3.4.1 List of Functions	148
14.3.4.2 Detailed Discussions of Bit 2	148
14.3.4.3 Detailed Discussions of Bit 3	148
14.3.4.4 Detailed Discussions of Bit 4	148
14.3.4.5 Detailed Discussions of Bit 6	148
14.3.4.6 Detailed Discussions of Bit 7	148
14.3.5 SSSW-SW05	148
14.3.5.1 List of Functions	148
14.3.5.2 Detailed Discussions of Bit 1	149
14.3.5.3 Detailed Discussions of Bit 2	149
14.3.6 SSSW-SW12	149
14.3.6.1 List of Functions	149
14.3.7 SSSW-SW13	150
14.3.7.1 List of Functions	150
14.3.7.2 Detailed Discussions of Bit 2	150
14.3.8 SSSW-SW14	150
14.3.8.1 List of Functions	150
14.3.8.2 Detailed Discussions of Bit 2	150
14.3.8.3 Detailed Discussions of Bit 4	150
14.3.9 SSSW-SW18	150
14.3.9.1 List of Functions	150
14.3.9.2 Detailed Discussions of Bit 0	151
14.3.9.3 Detailed Discussions of Bit 1	151
14.3.10 SSSW-SW25	151
14.3.10.1 List of Functions	151
14.3.10.2 Detailed Discussions of Bit 0	151
14.3.10.3 Detailed Discussions of Bit 2	151
14.3.11 SSSW-SW28	151
14.3.11.1 List of Functions	151
14.3.11.2 Detailed Discussions of Bit 0	152
14.3.11.3 Detailed Discussions of Bit 1	152
14.3.11.4 Detailed Discussions of Bit 2	152
14.3.11.5 Detailed Discussions of Bit 3	152
14.3.11.6 Detailed Discussions of Bit 4	152
14.3.11.7 Detailed Discussions of Bit 5	152
14.3.12 SSSW-SW30	152
14.3.12.1 List of Functions	152
14.3.12.2 Detailed Discussions of Bit 5	152
14.4 Menu Switch Settings (MENU)	152
14.4.1 Menu Switch Composition	152
14.4.2 <No.005 NL equalizer>	153
14.4.3 <No.006 telephone line monitor>	153
14.4.4 <No.007 ATT transmission level>	153
14.4.5 <No.008 V.34 modulation speed upper limit>	153
14.4.6 <No.009 V.34 data speed upper limit>	153
14.4.7 <No.010 Frequency of the pseudo CI signal>	153
14.5 Numeric Parameter Settings (NUMERIC Param.)	153
14.5.1 Numerical Parameter Composition	153
14.5.2 <002: RTN transmission condition (1)><003: RTN transmission condition (2)><004: RTN transmission condition (3)>	154
14.5.3 <005: NCC pause length (pre-ID code)>	154
14.5.4 <006: NCC pause length (post-ID code)>	154
14.5.5 <010: line connection identification length>	154
14.5.6 <011: T.30 T1 timer (for reception)>	154
14.5.7 <013: T.30 EOL timer>	154
14.5.8 <016: time length to first response at time of fax/tel switchover>	154
14.5.9 <017: pseudo RBT signal pattern ON time length><018: pseudo RBT signal pattern OFF time length (short)><019: pseudo RBT signal pattern OFF time length (long)>	154
14.5.10 <020: pseudo CI signal pattern ON time length><021: pseudo CI signal pattern OFF time length (short)><022: pseudo CI signal pattern OFF time length (long)>	154
14.5.11 <023: CNG detention level for fax/tel switchover>	154
14.5.12 <024: pseudo RBT transmission level at time of fax/tel switchover>	154
14.5.13 <025: Answering machine connection function signal detection time>	154
14.5.14 <027: V.21 low-speed flag preamble identification length>	154
14.5.15 <056 - 061: Count type select >	154
14.6 Scanner Function Settings (SCANNER)	157
14.6.1 Numeric Parameter Functional configuration	157
14.6.2 <031Vertical scan start position adjustment>	158
14.6.3 <033Vertical scan magnification correction>	158
14.6.4 <035: - 036:Reader motor speed change>	158
14.6.5 <041: Vertical scan start position adjustment (when scanning on a document fed from ADF)>	158
14.6.6 <047: Vertical scan magnification correction (when scanning on a document fed from ADF)>	158
14.6.7 <048: Horizontal scan magnification correction (when scanning on a document fed from ADF)>	158
14.7 Printer Function Settings (PRINTER)	159
14.7.1 Service Soft Switch Settings (SSSW)	159
14.7.1.1 SSSW-SW15	159
14.7.1.1.1 List of Function	159
14.7.1.1.2 Detailed Discussions of Bit 3	159
14.7.2 Numeric Parameter Settings (NUMERIC Param.)	159
14.7.2.1 <034: Left-end registration adjustment (malti-purpose tray)>	159
14.7.2.2 <035: Left-end registration adjustment (cassette)>	159
14.7.2.3 <039: Left-end registration adjustment (duplex unit)>	159
14.7.2.4 <053: Margin adjustment at the leading edge of the copy>	159
14.7.2.5 <054: Margin adjustment at the trailing edge of the copy>	159
14.7.2.6 <055: Margin adjustment at the right edge of the copy>	159
14.7.2.7 <056: Margin adjustment at the left edge of the copy>	159
14.8 Setting of System Functions (SYSTEM)	159
14.8.1 Bit Switch Settings	159
14.9 Counter Indication (COUNTER)	160
14.9.1 Counters	160
14.9.2 Clearing Counters	160
14.10 Report Output (REPORT)	161
14.10.1 Report Output	161
14.10.2 System Data List	161
14.10.3 System Dump List	162
14.10.4 Counter List	163
14.10.5 Spec List	164
14.11 Data Initialization Mode (CLEAR)	165
14.11.1 Clear	165
14.12 ROM Management (ROM)	165
14.12.1 ROM Display	165
14.13 Test Mode (TEST)	165
14.13.1 Overview	165
14.13.1.1 Outline	165
14.13.1.2 Test Mode Menu List	166
14.13.2 DRAM Test	167
14.13.2.1 D-RAM Test<(1) D-RAM TEST>	167
14.13.3 Scan Test	168
14.13.3.1 Scan Test ((2) SCAN TEST)	168
14.13.4 Print Test	168
14.13.4.1 Print Test ((3) PRINT TEST)	168
14.13.5 Modem Test	168
14.13.5.1 MODEM Test ((4) MODEM TEST)	168
14.13.6 Faculty Test	171
14.13.6.1 FUNCTION TEST <(6) FUNCTION TEST>	171
14.13.7 Cleaning Mode	174
14.13.7.1 Roller cleaning mode ((0) ROLLER CLEAN)	174
Chapter 15 Service Tools	175
15.1 Service Tools	179

Match case Limit results 1 per page

Chapter 5

5-2

5.2 Controlling the Laser Activation Timing

5.2.1 Laser ON / OFF Control

0016-1834

This is the control where the laser driver turns on / off the laser diode (LD) based on the laser control signal sent from the DCNT board.

The following is the circuit diagram for laser control.

F-5-2

The DCNT board sends the video signal (VDO, /VDO) for image formation and the laser control signal (CNT0, CNT1) for switching the laser operation mode to

the logic circuit in the laser driver IC.

The laser driver IC performs laser control based on the combination of CNT0 and CNT1 signals.

The following chart shows the combination of the laser control signals (CNT0, CNT1).

T-5-1

5.3 Controlling the Intensity of Laser Light

5.3.1 Auto Photoelectric Current Control (APC)

This is the control to emit the definite level of laser diode.

There are initial APC during initial rotation (note 1) and line space APC during printing (note 2), which are performed in the same procedure. The following is its

procedure.

1) When the laser control signal (CNT0, CNT1) turned into LD APC mode, the laser driver emits LD forcedly.

2) After being detected with the photodiode (PD), the LD emission level as current is converted to the one as voltage and compared with the reference voltage (the

voltage equivalent to the target laser level).

3) The laser driver controls the laser current until it reaches the voltage of LD target level.

4) When the laser control signal turns into LD forced OFF mode, LD is forcedly off and the laser driver converts the adjusted laser level to the voltage of the con-

denser and keeps it.

Note 1. Initial APC

APC during initial rotation. Laser level is adjusted by APC.

Note 2. Line space APC

APC during printing. Adjustment of laser level for one line is performed before writing one line.

Operation mode

CNT0

CNT1

Remarks

Discharge mode

Discharge of C803

Print mode

Use at normal printing

LD APC mode

Use at LD APC

LD forced OFF mode

Use at masking image

J931-8

-9

-5

-6

-3

-2

/BDI

CNT1

CNT0

VDO

/VDO

IC902

CPU

Laser driver circuit

+5V

SCNT board

J902-2

-1

-5

-4

-8

-7

/BD

VDO

/VDO

J901-6

-3

-2

Comparator

C803

DCNT board

BD sensor

Photo diode)

Laser diode)

Laser driver IC

Logic

circuit

Drive

circuit

Sample

hold

circuit