Read Sharp MX-6500N / MX-7500N (serv.man27) Service Manual online
MX-7500N OPERATIONAL DESCRIPTIONS 13 – 47
B. Operational descriptions
(1)
Outline of operations
This machine employs the fusing system by the belt.
The features of the belt-type fusing system are as follows:
1)
Short warm-up time
2)
Low power consumption
3)
Wide nip providing high fusing capability
(2)
Heater lamp driving
The surface temperature of the heat roller and the fusing belt
detected by the fusing temperature sensor is sent to the PCU. If the
temperature is lower than the specified temperature, the heater
lamp lighting signal is sent from the PCU to the heater lamp drive
circuit in the HL PWB.
detected by the fusing temperature sensor is sent to the PCU. If the
temperature is lower than the specified temperature, the heater
lamp lighting signal is sent from the PCU to the heater lamp drive
circuit in the HL PWB.
When the power triac in the heater lamp drive circuit is turned ON,
the AC power is supplied to the heater lamp to light the lamp and
heat the fusing belt.
the AC power is supplied to the heater lamp to light the lamp and
heat the fusing belt.
A thermostat is provided as a safety device against an abnormally
high temperature in the heat roller and the fusing belt.
high temperature in the heat roller and the fusing belt.
When the thermostat is opened, the AC power supply to the heater
lamp is cut off.
lamp is cut off.
The heater lamp is arranged to fusing roller (F1) and fusing roller
(B).
(B).
In heater lamp (HL_UM/US/UW), three lamps are integrated into
one.
one.
Heater lamp operations
Signal name
Name
Function/Operation
FPFD
Fusing front paper pass detector
Detects paper pass in front of the fusing section.
FUFM
Fusing cooling fan
Cools the fusing section and the paper exit section.
FUM
Fusing motor
Drives the fusing section.
HL_LM
Heater lamp lower main
Heats the fusing roller (B).
HL_UM
Heater lamp upper main
Heats the fusing roller (F1) and the fusing belt.
HL_US
Heater lamp upper sub
Heats the fusing roller (F1) and the fusing belt.
HL_UW
Heater lamp assist
Heats the fusing roller (F1) and the fusing belt.
HLPCD
Fusing pressure detector
Detects the fusing pressure state.
POD1
Fusing paper exit detector
Detects paper pass in the fusing section.
PRM
Fusing pressure control motor
Controls ON/OFF of the fusing pressure.
TH_LM/TH_LM_CS
Fusing temperature sensor lower
Detects the surface temperature at the center of the fusing roller (B).
TH_LM2
Fusing temperature sensor lower (Sub)
Detects the suffered temperature at the edge section of the fusing roller (B).
TH_UM/TH_UM_CS
Fusing temperature sensor upper (Main)
Detects the surface temperature at the center of the fusing belt.
TH_US/TH_US_CS
Fusing temperature sensor upper (Sub)
Detects the suffered temperature at the edge section of the fusing belt.
TH_US2
Fusing temperature sensor upper (Sub 2)
Detects the suffered temperature at the edge section of the fusing belt.
TS_L
Thermostat lower (Main)
Shuts down the heater lamp circuit when the fusing section is overheated.
TS_M
Thermostat upper (Main)
Shuts down the heater lamp circuit when the fusing section is overheated.
TS_S
Thermostat upper (Sub)
Shuts down the heater lamp circuit when the fusing section is overheated.
WEBEND2
Web end detector
Detects web end of the fusing unit.
WEBM2
Fusing web motor
Drives the fusing web roller.
No.
Name
Function/Operation
1
Fusing roller (F1)
Heats the fusing belt.
2
Fusing roller (F2)
The cushion layer of the roller forms a wide nip between the fusing belt and fusing roller (B).
3
Fusing roller (B)
Heats the back surface of paper to fuse toner on the paper.
4
Transport roller
Includes silicon oil in it and improves fusing separation and cleaning capabilities.
5
HL control PWB
Drives the heater lamp.
6
Fusing web roller
Cleans the fusing roller (B).
7
Discharge brush
Discharges static electricity generated in the fusing section to the ground.
8
Separation plate
Separates paper.
9
Separation pawl
Separates fusing roller (B) when it is attached.
10
Fusing belt
Heats the front surface of paper to fuse toner on the paper.
Heater lamp
Operation
Heater lamp upper
main (HL_UM)
main (HL_UM)
Heats the center of the fusing roller (F1) and the
fusing belt.
fusing belt.
Heater lamp upper
sub (HL_US)
sub (HL_US)
Heats the edges of the fusing roller (F1) and the
fusing belt.
fusing belt.
Heater lamp assist
(HL_UW)
(HL_UW)
Heats fusing roller (F1) and the fusing belt.
Turns ON when warming up.
Turns ON when warming up.
Heater lamp lower
main (HL_LM)
main (HL_LM)
Heats fusing roller (B). Does not turn ON while
heater lamp upper main (HL_UM) and heater lamp
upper sub (HL_US) light up.
heater lamp upper main (HL_UM) and heater lamp
upper sub (HL_US) light up.
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