Ricoh FT8880 Service Manual page 128

5 June 1992 SECTIONAL DESCRIPTION
2.2 SHIFT TRAY UP/DOWN MECHANISM
[E]
[D]
[F]
[A]
[B]
[H]
[J]
[C]
[I]
[G]
The vertical position of the shift tray [A] is controlled by the shift tray lift motor
(dc motor) [B] through the gears and the timing belts [C]. When the main
switch is turned on, the tray position is initialized to the upper position. The
tray's upper most position is detected when the shift tray pushes up the
actuator [D] to deactuate the stack height sensor 1 [E].
While copying, the actuator [D] is gradually raised as the copy stack grows. In
the sort/stack mode, when the stack height sensor 2 [F] remains actuated for
4 seconds, the shift tray lift motor [B] rotates, lowering the tray unit for 50 ms.
In staple mode, when the stack height sensor 1 remains deactuated for 4
seconds, the motor rotates lowering the tray until the sensor [E] is actuated.
When the tray reaches its lower limit position, the lower limit sensor [G] is
actuated by the actuator [H], and copy operation stops.
After the copy process is finished and the machine stops, the tray is raised to
its upper most position 4 seconds after the copies are removed.
A mechanical safety switch [I] is installed to prevent the drive gears from
being damaged if the sensor does not work. When the shift tray pushes up
the shift tray positioning roller [J], the shift tray lift motor stops.
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