Ricoh FT6645 Manual page 56

23 April 1993 OPTICS
3. OPTICS
3.1 OVERVIEW
[A]
[C]
[D]
[B]
[E]
The optics unit reflects an image of the original on the exposure glass onto
the OPC drum. This forms a latent electrical image of the original.
On this model a halogen lamp (85 V 230 W) is used for the exposure lamp
[A]. Lamp surface is frosted to ensure even exposure.
Six mirrors are used to make the optics unit smaller and obtain the wide
reproduction ratio range (50 ~ 200%).
The lens [B] is driven by two stepping motors for (1) vertical direction (parallel
to the paper feed direction) and (2) horizontal direction movements.
To correct focal length change in reduction and enlargement modes, the third
scanner unit [C] (4th and 5th mirrors) position is changed by a stepping motor.
The toner shielding filter [D] is green (a green filter partly absorbs red light)
to improve red original duplication.
The optic anti-condensation heater [E] (located on the optic base plate) turns
on while main switch is turned off to prevent the moisture from forming on the
optics.
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