Ricoh B022, Service Manual, Page: 81 / 878

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LASER EXPOSURE
SM 2-21 B022/B027
2.3 LASER EXPOSURE
2.3.1 OVERVIEW
The optical path from the laser diode to the drum is shown above.
The LD unit [A] outputs a laser beam to the polygon mirror [B] through the
cylindrical lens [C]. The shield glass [D] prevents dust from reaching the polygon
mirror.
Each surface of the polygon mirror reflects one full main scan line. The laser beam
goes to the F-theta mirror [E], mirror [F], and BTL (barrel toroidal lens) [G]. Then
the laser beam goes to the drum through the toner shield glass [H].
The laser synchronizing detector [I] determines the main scan starting position.
The speed of the polygon mirror motor is 28,818.9 rpm for 600 dpi.
B027D101.WMF
[A]
[B]
[C]
[D]
[E]
[F]
[G]
[H]
[I]