Optical Path - Gestetner A294 Service Manual

LASER EXPOSURE

2.4.2 OPTICAL PATH

[A]
[J]
The output path from the laser diode to the drum is shown above.
The LD unit [A] outputs four laser beams to the polygonal mirror [B] (six mirror
surfaces) through the cylindrical lens [C] and the 1st mirror [D].
Each surface of the polygon mirror reflects four full main scan lines. The laser
beams go to the F-theta lens 1 [E], F-theta lens 2 [F], BTL (barrel toroidal lens) [G],
and mirror [H]. Then these laser beams go to the drum through the toner shield
glass [I].
The laser synchronizing detector [J] determines the main scan starting position.
This board generates and sends a synchronization signal when the laser
synchronization detector mirror [K] reflects the laser beam to the detector as the
laser beam starts its sweep across the drum. The detector detects only the
uppermost beam (channel 1) of the four.
A294/A295
CÓPIA NÃO CONTROLADA
[D]
[C]
[K]
2-34
CÓPIA NÃO CONTROLADA
[B]
[E]
[F]
A294D101.WMF
[G]
[H]
[I]
SM