Engine F/W - Xerox phaser 3140 Service Manual

Theory of Operation

Engine F/W

2-18
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Control Algorithm
Feeding
The printer feeds the paper from the manual feeder when the Manual Feed Sensor
indicates that paper is present in the manual feeder.
When feeding from the Paper Tray, the drive of the Pick Up Roller is controlled by
the Pick Up Solenoid. While paper moves, the occurrence of a jam is judged as
follows.
Item Description
JAM 0 The leading edge of the paper did not pass the Feed Sensor.
After paper has been picked up, paper did not enter the printer.
After paper has been picked up, paper enters the printer, but did not
reach the Feed Sensor in the specified time.
If the Feed Sensor does not indicate On after paper has been picked
up, the printer re-picks. If after re-picking, the Feed Sensor is still not
activated, a JAM 0 error occurs.
This is an indication that the leading edge of the paper already
passed the Feed Sensor.
Even though paper reaches the Feed Sensor, the Feed Sensor is not
activated.
JAM 1 The paper is between the Feed Sensor and the Exit Sensor.
After the leading edge of the paper passes the Feed Sensor, the
trailing edge of the paper cannot pass the Feed Sensor in the
specified time. (The Feed Sensor cannot be OFF.)
After the leading edge of the paper passes the Feed Sensor, the
paper cannot reach the Exit Sensor in the specified time.
JAM 2 After the trailing edge of the paper passes the Feed Sensor, the paper
does not pass the Exit Sensor in the specified time.
Transfer
The charging voltage, developing voltage, and transfer voltage are controlled by
Pulse Width Modulation (PWM). Each output voltage is changeable due to the
PWM duty cycle. The transfer voltage used when the paper passes the Transfer
Roller is decided by environmental recognition. The resistance value of the Transfer
Roller changes due to the surrounding environment of the printer or the voltage
value. This change in resistance in turn changes the value of the voltage due to
loading. This voltage is fed back into the printer through the A/D converter. Based
on the value fed back, the PWM cycle is changed to maintain the required transfer
voltage.
Phaser 3140/3155/3160 Printer Service Manual