Canon NP6251 Service Manual page 8

2. Routing the Scanner Drive
Cable ........................................3-26
3. Orienting the Heat Absorbing
Glass ........................................3-26
4. Removing the Scanner Drive
Cable ........................................3-27
5. Adjusting the Tension of the
Scanner Drive Cable ................3-29
6. Positioning the Mirror ...............3-29
7. Adjusting the Scanner Home
Position.....................................3-30
8. Positioning the Scanner Locking
Solenoid (SL1)..........................3-31
B. Lens Drive Assembly.....................3-32
CHAPTER 4 IMAGE FORMATION SYSTEM
I. PROCESSES .....................................4-1
A. Controlling the Drum Surface
Potential.........................................4-1
1. Outline ......................................4-1
2. Control Method.........................4-2
3. Potential Measurement Circuit..4-4
B. Controlling the Intensity of the
Scanning Lamp .............................4-6
1. Outline ......................................4-6
2. Operation..................................4-7
3. Auto Exposure Control .............4-7
4. Making Checks.........................4-10
C. Controlling the Primary/Transfer
Corona Current..............................4-11
1. Outline ......................................4-11
2. Controlling the Primary
Corona Current.........................4-11
3. Controlling the Transfer
Corona Current.........................4-13
D. Controlling the Separation/Pre-
Transfer Corona Current ...............4-15
1. Outline ......................................4-15
2. Turning ON and OFF the
Separation/ Pre-Transfer
Corona Current.........................4-16
3. Separation Corona Current
(DC component) .......................4-17
4. Pre-Transfer Corona Current
(DC component) .......................4-17
5. Controlling the DC Component
of the Separation/Pre-Transfer
Corona Current.........................4-18
E. Controlling the Blanking Exposure
Lamp (LED) ...................................4-19
1. Outline ......................................4-19
2. Controlling the Activation in
Reduce Mode ...........................4-19
3. Controlling the Activation in
Direct Mode ..............................4-19
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1. Removing the Lens Y Direction
Drive Motor...............................3-32
2. Removing the Lens Stage
Temporarily ...............................3-34
3. Installing the Light-Blocking
Belt Mount ................................3-35
4. Removing the Lens X Direction
Drive Motor...............................3-36
5. Attaching the Lens X Direction
Drive Belt..................................3-37
6. Routing the Light-Blocking
Belt ...........................................3-37
7. Replacing the Light-
Blocking Belt.............................3-38
4. Controlling the Activation in
Sheet Frame Erase Mode ........4-19
5. Controlling the Activation in
Original Frame Erase Mode .....4-20
6. Controlling the Activation in
Book Frame Erase Mode .........4-20
7. Controlling the Activation in
Hole Image Erase Mode ..........4-21
8. Controlling the Activation in
AE Mode...................................4-21
F. Drum Heater Circuit.......................4-22
1. Outline ......................................4-22
2. Idle Rotation of the
Photosensitive Drum and the
Developing Cylinder .................4-24
G. Cleaning the Primary Charging
Wire ...............................................4-25
1. Outline ......................................4-25
2. Automatic Cleaning
Mechanism ...............................4-25
H. Pre-Transfer/Transfer/Separation
Charging Wire Automatic
Cleaning Mechanism .....................4-26
II. DRUM CLEANING ASSEMBLY
/DEVELOPING ASSEMBLY ...............4-28
A. Outline ...........................................4-28
B. Detecting the Level of Toner and
Controlling the Supply Operation ..4-30
C. Controlling the Developing
Bias/Roller Electrode .....................4-32
1. Outline ......................................4-32
2. Control Timing ..........................4-32
3. Developing Bias Control
Circuit .......................................4-35
4. Roller Electrode Bias Control
Circuit .......................................4-36
D. Detecting the Waste Toner Feeding
Screw (locking) ..............................4-38
III. DISASSEMBLY AND ASSEMBLY......4-39
CANON NP6350/NP6251 REV.0 JULY 1997 PRINTED IN JAPAN (IMPRIMÉ AU JAPON)