Lens Positioning - Ricoh FT7770 Service Manual

30
April, '89
LENS AND MIRROR POSITIONING
The lens/mirror motor has two functions:
It changes the lens position according to the selected reproduction ratio
(1)
to achieve the correct optical distance between the lens and the drum
surface.
It changes the second scanner position to achieve the proper distance be-
(2)
tween the exposure glass and the lens.

1. Lens Positioning

When a reproduction ratio is selected, the lens/mirror
its rotation is transmitted as follows:
Timing Belt -> Worm -> Worm Gear -> Lens Drive
Clamp on Lens Housing
So, the lens housing is moved either forward or backward along guide rod X
as the motor turns.
A stepping motor is used as the lens drive motor of this machine to meet
the functional requirement of 64% to 141% zoom range.
driven by pulses from the lens motor control board and accurately turns 1.8
degrees per pulse in either direction.
Related Service Call Condition: See FIELD MANUAL for details.
SC 15: Lens/Mirror Motor Failure
2-20
motor energizes
Pulley/Wire ->
This motor is
and