Ricoh FT8680 Service Manual page 52

OPTICS 31 July 1995
5.5 HORIZONTAL LENS DRIVE
[B]
[A]
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The original horizontal position on the exposure glass varies in modes (such
as platen, ADF, and CFF modes) for easy original handling. On the other
hand, the center is the standard position of the paper feed.
Therefore, the lens horizontal position has to be changed according to paper
size, reproduction ratio, and the original modes.
A stepper motor (approx. 7.5° (0.35 mm)/step) is used to drive the lens
through the lens drive wire.
The lens horizontal home position sensor [A] is used to detect the lens
horizontal position for A4/LT sideways, full size, and ADF mode.
The other positions are determined by counting the number of motor drive
pulses.
The lens horizontal drive encoder [B] installed on the drive pulley is used to
detect if the horizontal lens base locks.
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