Lexmark MS911 Service Manual page 652

The motor (punch drive) moves the punch unit frames in opposite directions. The motion causes the slots on the frames
to move the punchers up and down.
The chad accumulate in the hole punch box below the punch unit. When the light from the sensor (SHPF hole punch
box full, transmit) is blocked, the printer determines that the box is full.
# Part
1 Sensor (SHPF entrance)
2 Skew correction
3 Entrance roller
4 Diverter feed roller
5 Puncher
# Part
1 Puncher
2 Punch unit frames
3 Motor (punch drive)
Appendix C: Theory of operation
652
4021, 7421