Canon Vizcam 1000, Service Manual

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3. OPERATION AND TIMING
COPYRIGHT © 2001 CANON INC. CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-76
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.
Figure 3-422
The Y, M, C, and Bk patterns are as shown in
Figure 3-423.
Figure 3-423
CCDs for pattern reading
Y
Y
M
C
C
Bk
Bk
M
Feeding direction
Y drum C drum M drum Bk drum
Rear
Front
Image position correction pattern
Transfer belt
6mm
4mm
Feeding direction
Reading (CCD)
1st pixel
256th pixels