Ricoh VT3500, Service Manual

Page: 93 / 330

4.12 ELECTRICAL TIMING
T1: When paper is set on the paper table and the Print key is pressed, the
paper table moves up until the paper table height sensor is activated. 15
milliseconds after the height sensor is activated, the paper table brake
signal turns on for 50 milliseconds and SSR303 in the AC drive PCB is
energized. Brake force is then applied to the paper table drive motor to
prevent the paper table from overrunning.
T2: When the height sensor is activated, the transport vacuum motor and air
knife motors turn on. At the same time, the drum (main motor) starts
turning forward (printing direction).
T3: The paper feed solenoid is energized when the interrupter at the rear side
of the drum activates the second drum position sensor.
T4: After the paper is fed, the top of the paper stack is a little lower and the
height sensor is de-activated. When the second drum position sensor is
activated, the paper table drive motor starts rotating. This lifts the paper
table until the height sensor is re-activated (approximately 30 millisecond
after the motor starts). When the height sensor is re-activated, the motor
stops rotating.
T5: After the Stop key is pressed, the paper feed solenoid is de-energized
and the second drum position sensor is activated. This will reset the
counter on the operation panel.
T6: When the second drum position sensor is again activated after one more
drum rotation, the transport vacuum motor and air knife motors turn off.
Then, the drum rotates once more and stops at the first drum position
actuation position (the drum home position).
T1
T4
T5
T6
T3
T2
Paper Table Height Sensor
Paper Table Up Relay
Paper Table Brake Relay
First Drum Position Sensor
Paper Feed Solenoid
Second Drum Position Sensor
Transport Vacuum Motor
Air Knife Motor
Main Motor (Forward)
Paper Table Down Relay
15 msec
50 msec
30 msec
500 msec
Print key ON
Stop key ON
Counter Reset
(Table up)
1 December 1993
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