Service manual

Chapter 5
5-1
5.1 Construction
5.1.1 Outline
0006-4056
The laser scanner unit consists of the following major components:
- laser unit, which serves as the source of laser beam.
- laser scanner motor, equipped with a 4-face mirror for laser scanning.
- laser driver/BD PCB used to detect laser beam or to control emission of laser beam.
The laser beam generated by the laser unit based on the signals from the DC controller PCB moves through the
collimator lens (inside the laser unit) and the cylindrical lens to reach a 4-face polygon mirror rotating at a constant
speed.
When reflected by the 4-face polygon mirror, the laser beam moves through the imaging lens, and is bent by the
reflecting mirror to reach the photosensitive drum. At this time, the laser beam also is directed to the BD circuit of
the laser driver/BD PCB.
As the 4-face polygon mirror rotates at a constant speed, the laser beam scans the surface of the photosensitive drum
at a constant speed, thereby removing charges and forming static images.
F-5-1
Reflecting mirror
Laser driver/BD PCB
• copy image data
• print image data (if equipped with printer functions)
• fax image data (if equipped with fax functions)
Cylindrical lens
4-face mirror
DC controller PCB
Laser driver block
Photosensitive drum
Laser scanner motor
Laser unit
BD block
Imaging lens
Laser beam
detection signal
(BDI*)
Image signal
(VDO,VDO*)
Laser scanner
motor drive signal
Laser driver control signal
Communication
control
Horizontal sync signal
Image processor PCB