Canon 1000 Service Manual page 120

3. OPERATION AND TIMING
2. Forming and Reading Correction Patterns
As the first step in correcting image position, a pattern is formed. The image data for such patterns is
from the pattern generation RAM in the video controller, and patterns are formed on the transfer belt using
the data as when creating regular images for copies.
As shown in Figure 3-422, patterns are formed along the front and the rear ends in the order of Y, C, M,
and Bk and forwarded to the CCD for pattern reading.
Rear
Y
CCDs for pattern reading
Y
Image position correction pattern
Front
The Y, M, C, and Bk patterns are as shown in
Figure 3-423.
3-76
COPYRIGHT © 2001 CANON INC.
Bk drum
M Bk
C
Feeding direction
C Bk
M
Figure 3-422
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
C drum M drum
Transfer belt
Reading (CCD)
256th pixels
Feeding direction
1st pixel
Figure 3-423
Y drum
6mm
4mm