Kyocera Mita DF-75, Service Manual

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CHAPTER 2 OUTLINE OF OPERATION
6.2 Punching Operation
6.2.1 Outline
The puncher unit is located in the pickup assembly of the finisher, and is used to punch
holes in sheets that have been sent from the host machine and stopped inside it. When the trail-
ing edge of a sheet reaches the puncher unit, the inlet roller of the finisher assembly stops the
sheet to punch a hole along the trailing edge of the sheet.
The punch unit consists of a die and hole puncher (punch blade).
The hole puncher is driven by the punch motor (M1P). It is attached to the eccentric cam of
the punch shaft, and the rotation of the punch shaft is converted into reciprocating motion for
punching operation.
The punch motor (M1P) is a DC motor. The home position of the punch shaft is detected by
the punch home position sensor (PI1P). To make sure that the punch motor, which is a DC
motor, stops exactly at its home position, the punch motor is stopped in relation to the count of
the clock pulses kept by the punch motor clock sensor (PI3P).
A single punching operation is executed by rotating the punch shaft 180° from its home po-
sition.
As many as five light-receiving transistors (photosensor PCB) are mounted over the inlet
paper path of the puncher unit; on the other hand, as many as five LEDs (LED PCB) are
mounted under the path, together serving as five sensors. The frontmost sensor (LED5, PT5)
is used to detect the training edge of sheets, and the remaining four (LED1 through LED4,
PT1 through PT4) are used as horizontal registration sensors to detect the rear position of
sheets when punching holes.
The punch motor, punch unit, and sensors make up the punch slide unit, which moves to
the front/rear to suit the selected paper size. The movement to the front/rear is driven by the
horizontal registration motor (M2P). The home position of the punch slide unit is detected by
the horizontal registration home position sensor (PI2P), and the horizontal registration motor
(M2P) is a stepping motor.
The punch motor and horizontal registration motor are controlled with various commands
from the finisher controller PCB as well as the commands from the punch controller PCB.
The waste paper occurring as the result of punching is collected in the waste paper case. The
case is monitored by the LED121 on the waste full LED PCB and PT131 on the waste full
photosensor PCB.