Operations; Changing The Reproduction Ratio - Canon CLC 1120 Service Manual

2. Operations

The CPU (IC8) on the scanner motor driver PCB sends drive pulses to the motor according to
the scanning mode and distance and the selected reproduction ratio communicated by the CPU
PCB to control the rotation and speed of the motor.
To rotate the motor at a high speed when moving the scanner forward and in reverse, the motor
drive power is switched from 8 V (forward) to 40 V (reverse). (However, the motor is driven at 40
V even when moving the scanner forward at a reproduction ratio of 90%.)
The HOLD-OFF signal is used to prevent the motor from overheating while it is at rest in
standby state.
Related Error Code
E208
The communication between the scanner motor driver PCB and the CPU PCB is disrupted.
B. Changing the Reproduction Ratio
The reproduction ratio in main scanning direction (drum axial direction) is changed by reading
every so many image signals for reduction or reading the same image signals so many times for
enlargement.
The reproduction ratio in sub scanning direction is changed by moving the mirror mount faster
for reduction and slower for enlargement.
Scanner motor drive signal
Scanner motor driver PCB
COPYRIGHT © 1999 CANON INC.
Scanner motor
(PM15)
No. 2 mirror mount
CANON CLC1120/1130/1150 REV.0 MAR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 3 EXPOSURE SYSTEM
(forward)
No. 1 mirror
mount
Scanner HP sensor (PS1)
Figure 3-202
Signal plate
CPU PCB
3-5