Ricoh IS450S Service Manual page 23

22 December 1998 SCANNER MECHANISMS
Document Table Lift
[C]
[G]
[F]
[A]
[H]
[B]
[E]
[D]
[F]
[A]
G411D518.PCX
The lift mechanism consists of the document table lift clutch [A], the lift shaft [B],
the document table position sensor [C], and the sensor actuator on the gear [D].
In standby mode, the bend in the lift shaft [H] is pointing downwards and the
actuator is just inside the sensor.
When an original is placed on the document table, the document sensor [E] is
activated. Then the paper feed motor [G] turns on. At the same time, the document
table lift clutch [A] turns on to rotate the lift shaft.
At this time, the actuator starts to turn anticlockwise, and the flat part of the spring
[I] that is loosely attached to the bend in the lift shaft pushes up the document table
(see the next page for a diagram).
When the top of the document stack is pushed up against the pick-up roller, it can
rise no more. However, the mechanism continues to push up against the tray until
a half-turn of the shaft has been completed (i.e., until the actuator leaves the
document table position sensor). At that time, the document table lift clutch and the
paper feed motor turn off. If the actuator does not leave the sensor within a certain
time, a document table error will occur.
The feed motor turns on again at a motor speed which depends on the scanning
resolution, and the pick-up clutch [F] turns on to feed the top sheet of the original
(see Original Feed and Separation).
2-9