Canon PC980 Service Manual - Page 54

CHAPTER 3 EXPOSURE SYSTEM D. Scanner Drive System 1. Outline The scanner is driven by the scanner/lens drive motor (M2), whose direction of rotation changes to move the scanner forward or in reverse. When moving the scanner forward, the speed of rotation of the motor varies according to the selected reproduction ratio on a continuous basis; when moving the scanner in reverse, on the other hand, its speed remains the same regardless of the selected reproduction ratio in normal copying (312mm/sec, about 3.3 as fast as when moving the scanner forward in Direct). The distance over which the scanner is moved varies according to the length of copy paper and the selected reproduction ratio. The scanner/lens drive motor dives the lens drive system as well as the scanner. M2 SC_COM SC_B* SC_B SC_COM SC_A* SC_A PS1 Light-blocking plate Scanner home position signal (SCHP) Scanner home position sensor (PS1) J110-1 -2 -3 -4 -5 -6 J101-1 Figure 3-104 Q109 Motor driver circuit DC controller PCB 3-4 COPYRIGHT © 1999 CANON INC. CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)