Timing - Ricoh LDD280 Service Manual

6.9.10 TIMING

1st drum position sensor
Feed start sensor
Paper feed motor
Paper registration
sensor
Registration Motor
Feed timing sensor
Feed encoder sensor
1. The feed start sensor turns on when drum turns 184 and 307 degrees.
2. The feed start sensor turns on when the drum turns 184 degrees. Soon after this,
the paper feed motor turns on.
3. The paper feed motor turns off a short time after the registration sensor turns on,
to ensure sufficient paper buckling to prevent skew.
4. When the drum turns to 307 degrees, the machine counts for a few pulses from
the feed encoder sensor (number of pulses adjustable with SP 6-020). Then the
registration motor turns on.
5. The machine counts the pulses from starting the registration motor until the
paper feed timing sensor turns on. The number of pulses determines the
amount of slip that is detected. The machine changes the time that paper feed
starts, based on this number of pulses. This ensures that paper feed starts at
the correct time.
6. There is some play in the pressure cylinder drive mechanism. This means that
the cylinder does not start at exactly the same time as the main motor. To
correct this, the machine monitors the feed encoder on the pressure cylinder
and adjusts the speed of the registration motor.
7. The paper feed motor stops when it turns 80 degrees after the passing the 1
drum position sensor.
SM
PRINTING AND PRESSURE CYLINDER
0 degree
degrees
6-111
184 269
degrees
307 degrees
80 degrees
st
C262/C265