Canon 1000 Service Manual page 122

3. OPERATION AND TIMING
This correction is executed at the following timing:
1 When the power switch is turned on.
2 When the Start key is pressed after a specific period of time* following a press on the power-switch.
*Every two hours after 20 min, 40 min, 60 min, 90 min, and 120 min.
3 After jamming.
4 When activated in service mode.
The pattern is formed as follows:
When the power switch is turned on, the Y pattern is formed as soon as the fixing temperature reaches
110°C; then, the M pattern is formed after a specific period of time has passed (photosensitive drum-to-drum
distance and pattern interval of 7 mm; for the C and Bk patterns, see Figure 3-427). Thereafter, the Y pattern
is formed as soon as the photosensitive drum completes a half rotation. When a total of 8 sets of patterns
have been made (Y, M, C, Bk), the average of the data values is computed.
The reading by the CCD is synchronized with the periods of time that pass following the generation of the
Y image print enable signal.
Drum revolution
Potential control
Y image print enable signal (YPE)
M image print enable signal (MPE)
C image print enable signal (CPE)
Bk image print enable signal (BkPE)
Pattern read signal (CCDRD)
Y
4mm
3-78
COPYRIGHT © 2001 CANON INC.
Power switch ON
110ºC
Drum 1/2 rotation
Drum-to-drum
distance + 7mm
Figure 3-426
M
7mm
4mm
Figure 3-427
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
INTR
1 2
Drum 1/2 rotation Drum 1/2 rotation Drum 1/2 rotation
Drum-to-drum
distance + 14mm
C
7mm 4mm
3
Drum 1/2 rotation Drum 1/2 rotation
Drum-to-drum
distance + 21mm
Y M C Bk
Bk
7mm
4mm