Ricoh Di-C1 Manual page 336

Two-hole and Four-hole Punch Units
Punch
Guide
Hole
Punch
For the first sheet of paper, the punch motor moves the slider
plate to the rear.
The punch guide forces the hole punch to move down, to punch a
hole in the paper.
The punch motor continues to rotate in the same direction, until
home position is detected again.
The punch motor then changes direction to punch the holes in
the next sheet of paper. The slider plates move to the rear again,
to punch the holes in the paper.
Slide 336
The punch motor alternately turns forward and in reverse for alternate sheets
of paper. But the slider plate always moves to the rear to punch the paper,
because of the shape of the groove in the cam.
Why does the punch unit change direction between sheets? This is so that
the actuator of the punch waste detection mechanism can move back across
the punch waste hopper. It is driven by the same motor, and if the motor
turns in the same direction for a long time (during a long job), punch waste
can build up without being detected.
336
Di-C1 Training