Dual Beam Writing - Gestetner G060 Service Manual

LASER EXPOSURE

6.3.4 DUAL BEAM WRITING

Dual Beam Mechanism
The LD unit for black has two laser diodes. Each face of the polygon mirror writes
two main scan lines. This only happens for black and white printing.
Laser Beam Pitch Change Mechanism
[A]
[B]
G060D253.WMF
The machine changes the main scan resolution between 600 and 1,200 dpi for
black and white by rotating the LD unit [A], except for OHPs and thick paper.
Both LD unit positions are fixed distances from the LD home position sensor [B].
When the number of times that the resolution has changed reaches a certain
number, the LD positioning motor moves the LD unit to the home position, and
then to the proper position.
After the laser optics housing unit has been replaced, the beam pitch for 600 dpi
and 1200 dpi must be adjusted (SP2-109-2, -3).
G060 6-20 SM