Laser Exposure - Ricoh B079 Service Manual

6.6 LASER EXPOSURE

6.6.1 OVERVIEW
4
3
2
1
1 LD unit
2 Cylindrical lens
3 Polygonal mirror
4 Shield glass
5 Mirror
This machine uses two laser diodes to produce electrostatic images on an OPC
drum. The laser diode unit converts image data from the BICU board into laser
pulses, and the optical components direct these pulses to the drum. To produce a
high quality copy image, these are 256 gradations for the laser power.
The output path from the laser diode to the drum is shown above. The LD unit
outputs two laser beams to the polygon mirror through the cylindrical lens and the
shield glass.
Each surface of the polygon mirror reflects two full main scan lines. The laser
beams go to the F-theta mirror, mirror, and BTL (barrel toroidal lens). Then these
laser beams go to the drum through the toner shield glass. The laser synchronizing
detector determines the main scan starting position.
NOTE: The front door and right door (transfer door) are equipped with safety
switches that automatically shut down the laser unit when either door is
opened.
SM
CÓPIA NÃO CONTROLADA
6 7
5
6 Synchronizing detector
7 BTL (Barrel Toroidal Lens)
8 F-theta mirror
9 Toner shield glass
6-47
CÓPIA NÃO CONTROLADA
LASER EXPOSURE
8
B004D541.WMF
9
B079/B082