Ricoh G081, Service Manual

Page: 173 / 272

PRINT PROCESS
SM 6-11 G081/G092
Detailed
Des
cription
s
6.3.3 LASER EXPOSURE
Laser scanning
[A]: Laser diodes
[B]: Collimator lens
[C]: Polygon mirror
[D]: Synchronization sensor [E]: Horizontal synchronization mirror
[F]: Toroidal correction lens
[G]: Laser optics housing unit
Laser path
The laser diodes [A] (one for each color and black) generate the laser beams used
to “expose” the OPC’s surface.
The collimator lens [B] ensures the beams are parallel, and directs them to the
polygon mirror [C].
The toroidal correction lens [F] corrects the vertical registration errors of the
beams.
Mirrors direct the beams to the primary lenses (at the bottom of the unit). The
lenses ensure that each beam scans across the drum at a constant speed.
Laser synchronization
At the start of each horizontal scan, the horizontal synchronization mirror [F]
deflects the laser beam to the horizontal synchronization sensor [D].
Synchronization is done for the black laser beam only. The other lines depend on
the line position adjustment.
G081D105.WMF
[A]
[B] [D]
[E]
[F]
[G]
[C]