Stabilizing Images - Canon 1000 Service Manual

C. Stabilizing Images
1. Outline
Copy images change over time for the
following factors:
• Change in the amount of charging by the
primary charging assembly.
• Change in the sensitivity of the photosensitive
drum.
• Change in the charging characteristics of
the developer.
To ensure stable images in spite of these factors, the CLC1000 provides an image stabilizing control
mechanism. When the power switch is turned on, the appropriate grid and developing biases are determined
with reference to the data from the potential sensor; during copying, the grid bias is corrected based on the
data from the environment sensor.
The grid bias and the developing bias are corrected and the laser output is corrected based on the
correction data from PASCAL (explained later).
DC controller PCB
Laser output
Potential control
Vdc
Vg
PASCAL
Photosensitive
drum
SALT sensor
COPYRIGHT © 2001 CANON INC.
Environment sensor
Potential sensor
Developing cylinder
Figure 3-505
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
3. OPERATION AND TIMING
Primary charging assembly
Change in
charging
Photosensitive
drum
Deterioration
in sensitivity
Figure 3-504
Power switch ON
Potential control
Determines grid bias (Vg) and
developing bias (Vdc)
Change in charging
characteristics of developer
Developing
assembly
Environment sensor
PASCAL
3-87