Ricoh FT5034 Service Manual page 30

This model uses a dc servomotor to drive the scanners.
The scanner motor changes the scanner speed depending on the reproduction ratio.
3. Lens/Mirror Positioning
The lens motor (a stepping motor) changes the
lens and 2nd scanner position in accordance
with the selected reproduction ratio to provide
the proper optical distance between the lens
and the drum surface.
1. Lens Positioning
The output gear of the lens motor engages
the gear of the lens drive pulley directly.
The lens drive wire is wrapped around the
lens drive pulley and is connected to the
lens drive bracket. As the lens motor is a
stepper motor, the rotation of the lens drive
pulley moves the lens back and forth in
discrete steps.
The lens home position sensor informs the
optics CPU (IC403) when the lens is at the
full size position (home position). The
optics CPU determines the lens stop
position in reduction and enlargement
modes by counting the number of steps the
motor makes.
When the reproduction ratio is changed,
the lens moves directly to the selected lens
position.
When the lens moves from one
enlargement ratio to another or from one
reduction ratio to another, it does not
moves to the home position.
Lens Drive Wire
Lens Drive
Pulley
Lens Motor
(Reduction)
- 29 -
Lens Home
Position Sensor
Lens Drive Bracket
Lens Movement
Full Size
Lens H.P.
Sensor
(Enlargement)