Canon GP160, Service Manual

Page: 89 / 797

COPYRIGHT © 1999 CANON INC. CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 5 LASER EXPOSURE SYSTEM
5-1
I. OVERVIEW
The principal parts making up the laser scanner unit are; the laser beam generating
laser unit, the laser scanner motor which contains a six sided mirror for laser scanning
and a BD sensor PCB for detection the laser beam.
The laser beam generated by the laser unit illuminates the 6 sided mirror, which
rotates at a fixed speed. The laser beam reflected by the 6 sided mirror is filtered
through a condensing lens in order to be focussed on the photosensitive drum. The optic
path is bent by the lens mirror, and the beam arrives at the photosensitive drum. Then,
the laser beam reflected by the BD mirror installed in the laser scanner unit is illuminat-
ed onto the BD sensor PCB. (Refer to Figure 5-102)
When the 6 sided mirror is rotating at a fixed speed, the laser beam is scanned onto
the photosensitive drum at a fixed speed, the static charge eliminated and then an elec-
trostatic latent image formed.
Figure 5-101
Lens
Scanning lamp
Mirror 1
Mirror 2
Mirror 3
Image processor
PCB
DC controller
PCB
Laser
driver Laser beam
Laser mirror
Photo-
sensitive
drum
CCD light receiving unit
Analog processor PCB
Copyboard glass
Mirror 4
Laser scanner unit