Laser Exposure; Overview - Ricoh G165 Service Manual

6.3 LASER EXPOSURE

6.3.1 OVERVIEW

1. LD unit - C/M
2. Fθ Lens
3. Polygon Mirror Motor
This machine uses two LDB units and one polygon mirror motor to produce latent images
on four OPC drums (one drum for each color toner).
There are two hexagonal mirrors. The polygon mirror motor rotates the mirrors clockwise
and each mirror reflects beams from the LD unit.
The laser beam from the LD unit - C/M is directed to the Fθ lens at rear side by the polygon
mirrors. The laser beam from the LD unit - K/Y is directed to the Fθ lens at front side by the
polygon mirrors.
Laser exposure for magenta and cyan starts from the left side of the drum, but for yellow
and black it starts from the right side of the drum. This is because the units for magenta and
cyan are on the other side of the polygon mirror from the units for yellow and black.
The machine has one laser synchronizing detector board (LSD) as shown above. The
board detects four colors. The LSD detects the start of the main scan.
SM
4. Synchronizing Detector Board
5. LD unit - K/Y
6-17 G165/G166/G167/G181/G183/G184
Laser Exposure