Fusing Section - Sharp MX-C250 Service Manual

'13/Oct
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14. Fusing section

A. Electrical and mechanism relation diagram
Signal name
FUFM Fusing cooling fan motor
FUM Fusing drive motor
HL_LM Heater lamp (HL\LM)
TH_UM Thermistor UM
TH_US Thermistor US
TS_UM Thermostat UM
B. Fusing unit drive
The driving of fuser unit is; the driving force is transported to fuser
roller, thru the fuser motor (FUM) and connection gears, based on
the controlling signal from PCU.
Name
Cools the fusing unit.
Drives the fusing unit.
Heats the fuser heat roller.
Regulates Heat Roller Temperature at center of the Heat Roller.
Regulates Heat Roller Temperature at the end of the Heat Roller.
Fusing roller overheat protection. Cuts off power supply to heat lamp when over heat condition
is determined.
MX-C250 OPERATIONAL DESCRIPTIONS 11 – 22
Function and operation
C. Heater lamp drive
The temperature on the fuser roller which detected by fuser therm-
istor is transferred to PCU.
If above temperature is low than predetermined one, PCU sends
the heater lamp signal to the heater lamp drive circuit in HL-PWB.
The power triac in heater lamp drive circuit is turned ON, then AC-
power is supplied to heater lamp. Finally the heater lamp is turned
ON and fuser roller (heat roller) is heated up. If above temperature
is higher than predetermined one, PCU stops send the heater lamp
signal to the heater lamp drive circuit in HL-PWB.
In case of abnormal high temperature of fuser roller (heat roller) is
occurred, the thermostat becomes OFF condition, physically cuts
off the power line of heater lamp.
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