Laser/Scanner System; Outline - Canon LBP-1760 Service Manual

CHAPTER 2
III. LASER/SCANNER SYSTEM
A. Outline
Focusing lens
Mirror
BD mirror
The VIDEO signal (/VDO) is sent from the video controller to the laser driver of the laser/scan-
ner unit through the engine controller.
The laser driver turns the laser diode ON and OFF according to the /VDO signal and gener-
ates the modulated laser beam only when the VIDEO DATA ENABLE (/ENBL) signal from the
engine controller is "L."
The modulated laser beam is aligned by a collimator lens and a cylindrical lens into a paral-
lel beam. It then strikes the scanning mirror which is rotating at a constant speed.
The beam reflected from the scanning mirror is brought to a point of focus on the photosen-
sitive drum by the focusing lens and mirror.
As the scanning mirror rotates at a constant speed, the beam is scanned across the drum at
a constant speed.
The photosensitive drum also rotates at a constant speed allowing the laser beam to form an
image on the drum surface.
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Scanner motor
Scanning mirror
Figure 2-3-1
Engine
controller
/ACC
/DEC
Cylindrical lens
Laser driver
HALF
/LON
/ENBL
/VDO
/BDI
Video
controller
/BD
/TOP
/VDO