Canon PC980 Service Manual - Page 53

CHAPTER 3 EXPOSURE SYSTEM 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 . In this condition, when the 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 appropriate front/rear widths to suit the selected reduction ratio. SL3 ON Switching gear SL3 OFF Switching gear Lens solenoid drive signal(LNSLD*) Lens home position detection signal(LHP) While the lens is moving Switching gear SL3 Lens cable While the scanner is moving Top View Cam Scanner/lens drive motor (M2) No. 4/5 mirror unit Reduction Enlargement Lens home position sensor (PS2) Lens unit Lens shift detecting shaft for side blanking lamp DC controller PCB Figure 3-103 COPYRIGHT © 1999 CANON INC. CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 3-3