Canon Vizcam 1000, Service Manual

Page: 131 / 840

COPYRIGHT © 2001 CANON INC. CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-87
3. OPERATION AND TIMING
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.
Figure 3-504
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).
Figure 3-505
Photosensitive
drum
Deterioration
in sensitivity
Change in
charging
Change in charging
characteristics of developer
Developing
assembly
Primary charging assembly
Photosensitive
drum
SALT sensor
Potential sensor
Environment sensor
Potential control
Vdc Vg
Laser output
PASCAL
DC controller PCB
Developing cylinder
Power switch ON
Potential control
Environment sensor
PASCAL
Determines grid bias (Vg) and
developing bias (Vdc)
Target contrast potential