Image Formation System; Outline - Canon 1000 Service Manual

3. OPERATION AND TIMING
V. IMAGE FORMATION SYSTEM
A. Outline
The functions of the image formation system covers the following:
• Controls the drum surface potential (controls primary charging assembly grid bias/developing bias)
• Controls gradation correction (laser output control)
• Controls primary corona current
• Controls pre-primary corona current
• Controls developing bias
• Controls toner supply
• Detects Bk/color toner density
• Controls transfer current
• Controls separation corona current
Feedback is obtained by the following sensors:
• Environment Sensor
Measures the temperature/humidity inside the machine. (Corrects the grid bias, separation charging
bias, and transfer blade bias.)
• Potential Sensor
Measures the photosensitive drum surface potential. (Corrects the grid bias and developing bias.)
• Color Toner Density Sensor
Measures the toner density in the developer. (Supplies color toner.)
• SALT Sensor
Measures the toner density on the photosensitive drum. (Supplies black toner/color toner.)
• Original Exposure CCD (PASCAL)
Measures the toner density on copies by the CCD. (Corrects the grid bias, developing bias, and laser
output.)
HVT3
PASCAL
SALT sensor
3-84
COPYRIGHT © 2001 CANON INC.
DC controller PCB
HVT2
Potential sensor
Photosensitive
drum
Figure 3-501
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
Toner supply
clutch
Color toner density sensor
Environment
sensor
Laser output