Lens Drive System - Canon PC920 Service Manual

C.

Lens Drive System

1. Outline
The lens drive system is driven by the scanner/lens drive motor (M2). When the lens solenoid
(SL3) turns on, the switching gear is pushed in the direction of
scanner/lens drive motor rotates in reverse direction ( ), the lens unit will move in the direction of
reduction ( ) by the work of the gear and the lens cable.
At the same time, the No. 4/5 mirror unit operates according to the distance over which the lens
unit is moved by the work of the gear and the cam, thereby varying the optical length.
At this time, the blanking lamp also moves in conjunction with the lens to blank out the appro-
priate front/rear widths to suit the selected reduction ratio.
Lens cable
DC controller PCB
COPYRIGHT © 1999 CANON INC.
SL3
ON
Switching
gear
While the lens is moving
Switching gear
SL3
Lens home position
sensor (PS2)
Lens shift detecting shaft
for side blanking lamp
Figure 3-103
CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 3 EXPOSURE SYSTEM
While the scanner is moving
Top View
Cam
Enlargement
Lens unit
. In this condition, when the
SL3
OFF
Switching
gear
Scanner/lens drive motor
(M2)
No. 4/5 mirror unit
Reduction
3-3