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ASIC(SPGP)
Motor Drive Circuit
The main motor drives the following.
• Paper feed unit
• Developing unit
• Fusing unit
• Exit assembly
Software controls the acceleration, constant speed and deceleration. A A3977
driver IC drives the motor.
Transfer
PWM (Pulse Width Modulation) controls the charging voltage, developing voltage
and the transfer voltage. The output voltage changes according to the PWM duty
cycle. Environment recognition detects the transfer voltage used when the paper
passes the transfer roller. The surrounding environment in the room or within the
machine changes the resistance value of the transfer roller. This change in
resistance in turn changes the value of the voltage due to loading. This voltage is
fed back into the machine through the A/D converter. The PWM cycle changes to
maintain the required transfer voltage based on this value.
Fusing
The resistance value of the thermistor detects the temperature of the heat roller's
surface. The A/D converter measures the thermistor resistance and lets the CPU
determine the temperature of the heat roller. The AC power is controlled by
comparing the target temperature to the value from the thermistor. An error shows
if the value from the thermistor is out of the controlling range during the fusing
process.
Error Type
Error
Open heat error
Low heat error
Over heat error
Description
Temperature stays lower than 68 C for
more than 28 seconds during warm-up.
Standby: Temperature stays lower than
80 C for more than 10 seconds.
Printing:
Temperature stays lower than 145 C for
more than 4 seconds for up to two
consecutive print jobs.
Temperature stays 25 C lower than the
fixed fusing temperature for more than 4
seconds for up to two consecutive print
jobs.
Temperature stays higher than 220 C
for more than 3 seconds.
Temperature stays higher than 220 C
for more than 3 seconds.
LED Display
All LEDs flash
All LEDs flash
All LEDs flash
6-16
20 July 2005
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