Canon NP7160 Service Manual page 10

CHAPTER 3 EXPOSURE SYSTEM
I. OUTLINE OF OPERATION ..................... 3-1
A. Changing the Reproduction Ratio ...... 3-1
II. LENS DRIVE SYSTEM ............................ 3-3
A. Driving the Lens ................................. 3-3
1. Outline .......................................... 3-3
2. Motor Control Circuit .................... 3-4
3. Moving the Lens ........................... 3-5
III. SCANNER DRIVE SYSTEM .................... 3-6
A. Outline ................................................ 3-6
B. Scanner Motor Control Circuit ........... 3-7
C. Relationship between Scanner
Sensor and Signals ............................ 3-7
D. Basic Sequence of Operations
(scanner) ........................................... 3-8
E. Scanner Movement in
Page Separation Mode ...................... 3-9
IV. OTHERS ................................................. 3-10
A. Detecting the Original Size .............. 3-10
CHAPTER 4 IMAGE FORMATION SYSTEM
I. OUTLINE OF THE PROCESSES ............ 4-1
A. Outline ................................................ 4-1
B. Basic Sequence of Operations
(image formation system) .................. 4-2
C. Controlling the Intensity of the
Scanning Lamp .................................. 4-3
1. Outline .......................................... 4-3
2. Operation ...................................... 4-4
3. Protection Mechanisms ............... 4-5
D. Controlling the Primary/Transfer Bias .. 4-6
1. Outline .......................................... 4-6
2. Turning On/Off the Primary/
Transfer Bias ................................ 4-6
E. Controlling the Developing/Separation
Static Eliminator Bias ......................... 4-7
1. Outline .......................................... 4-7
2. Turning On/Off the Developing
DC Bias ........................................ 4-8
3. Turning On/Off the Developing
AC Bias/Separation Eliminator
Bias .............................................. 4-9
4. Controlling the Developing
DC Bias to a Specific Voltage
to Suit Copy Density .................. 4-10
F. Controlling the Blank Exposure Lamp ... 4-12
1. Outline ........................................ 4-12
2. Turning On the Blank Exposure
Lamp in Reduce Mode ............... 4-13
3. Turning On the Blank Exposure
Lamp in Direct/Enlarge Mode .... 4-13
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1. Outline ........................................ 3-10
2. Detection of the Original Size
by the ADF ................................. 3-10
V. DISASSEMBLY/ASSEMBLY ................. 3-11
A. Scanner Drive Assembly .................. 3-12
1. Removing the Scanner Motor .... 3-12
2. Removing the Scanner Drive
Cable .......................................... 3-13
3. Routing the Scanner Drive
Cable .......................................... 3-15
4. Adjusting the Position
of the Mirror ................................ 3-16
5. Adjusting the Tension
of the Scanner Drive Cable ........ 3-17
B. Lens Drive Assembly ....................... 3-18
1. Removing the Lens Drive
Motor .......................................... 3-18
2. Removing the Mirror Motor ........ 3-19
4. Turning On the Blank Exposure
Lamp in Multifeeder Mode ......... 4-13
II. DEVELOPING ASSEMBLY/DRUM
CLEANER ASSEMBLY .......................... 4-14
A. Outline .............................................. 4-14
B. Detecting and Controlling
the Level of Toner ............................ 4-16
C. Monitoring the Waste Toner
Feeding Screw ................................. 4-17
D. Monitoring the Waste Toner Box ..... 4-18
E. Control by the Cleaner Thermistor ... 4-20
1. Copying Speed Down
Sequence ................................... 4-20
F. Auto Density Adjustment (AE) ......... 4-21
1. Outline ........................................ 4-21
2. Measuring the Density
of the Original ............................. 4-21
III. DISASSEMBLY/ASSEMBLY ................. 4-23
A. Scanning Lamp Assembly ............... 4-24
1. Removing the Scanning Lamp .. 4-24
2. Mounting the Scanning Lamp .... 4-25
3. Removing the Thermal Fuse ..... 4-25
B. Exposure Assembly ......................... 4-26
1. Removing the Pre-Exposure/
Blank Exposure Lamp
Assembly .................................... 4-26
2. Removing the Dust-Proofing
Glass .......................................... 4-26
3. Cleaning the No. 6 Mirror ........... 4-27
C. Drum Unit ......................................... 4-28
CANON NP7161/NP7160 REV.0 AUG. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)