Sharp MX-5000N

MX-5001N FUSER SECTION M – 2
2. Operational descriptions
A. Fusing unit drive
For driving the fusing unit, the drive power is transmitted from the
drive motor (FUM) through the connection gear to the upper heat
roller gear.
Driving by the drive motor (DC brushless motor) is performed
according to the control signal sent from the PCU.
B. Heater lamp drive
The surface temperature of the heat roller detected by the ther-
mistor is sent to the PCU. When the temperature is lower than the
specified level, the heater lamp ON signal is sent from the PCU to
the heater lamp drive circuit on the HL PWB.
The power triac in the heater lamp drive circuit is turned on, and the
AC power is supplied to the heater lamp, lighting the lamp and
heating the heat roller.
To prepare for an abnormally high temperature of the heat roller,
the thermostat is provided for safety.
When the thermostat is opened, the power supply (AC line) to the
heater lamp is cut off.
C. Fusing operation
Color toner (Y,M,C,K) on paper is subject to heat and pressure to
be fused on paper.
At that time, color toner of Y, M, C, and K are mixed to reproduce
colors approximate to the document image colors.
The heater lamps are provided in the lower and the upper heat
roller to heat paper from the upper and the lower sides.
This is because paper must be heated both from the upper side
and from the lower side together in order to melt and fuse toner in
the four layers on the paper.
The upper and the lower heat rollers of silicon rubber are
employed.
This is because of the following reasons.
1) To increase the nip quantity. To increase the heating capacity
for paper.
2) By pressing the flexible roller, multi-layer toner can be fused
without deformation.
3) An even pressure can be applied to rough surface of toner lay-
ers (multi-layer structure).
Signal name Name Function/Operation
FUM Fusing motor Drives the fusing unit.
HL_LM Heater lamp lower main Heats the fusing roller (pressing).
HL_UM Heater lamp upper main Heats the fusing roller (heating).
HL_EX1 Heater lamp external 1 Heats the fusing roller (heating). (External)
HL_EX2 Heater lamp external 2 Heats the fusing roller (heating). (External)
HLPCD Fusing pressure release sensor Detects pressure release of the fusing roller.
TS MAIN Thermostat (1) Shuts conduction to the heater lamp when the temperature rises abnormally. [For the fusing roller (heating)]
TS EX1 Thermostat (2) Shuts conduction to the heater lamp when the temperature rises abnormally. [For the fusing roller (heating)]
(External)
TS EX2 Thermostat (3) When the temperature rises abnormally, conduction to the heater lamp is cut off.
[For the fusing roller (heating)] (External)
TS SUB Thermostat (4) When the temperature rises abnormally, conduction to the heater lamp is cut off.
[For the fusing roller (pressing)] (External)
PRM Fusing pressure release motor Adjusts the fusing roller pressure.
TH_UM Fusing temperature sensor (1) Detects the surface temperature of the fusing roller (heating). (Center section)
TH_US Fusing temperature sensor (2) Detects the surface temperature of the fusing roller (heating). (Edge section)
TH_LM Fusing temperature sensor (3) Detects the surface temperature of the fusing roller (pressing).
TH_EX1 Fusing temperature sensor (4) Detects the surface temperature of the heat roller (external).
TH_EX2 Fusing temperature sensor (5) Detects the surface temperature of the heat roller (external).
WEB-END Web roller end detection Detects presence of cleaning paper.
WEBM Fusing web cleaning motor Drives the fusing web cleaning paper.
No. Name Function/Operation
1 Fusing roller (Heating) Applies heat and pressure to toner on paper to fuse it on paper.
2 Upper separation pawl Mechanically separates paper which was not naturally separated from the fusing roller (heating).
3 Fusing roller (Pressing) Applies heat and pressure to toner on paper to fuse it on paper.
4 Transport roller 9 (Drive) Transports paper from the fusing roller to the paper exit roller 1.
5 Web roller Cleans the upper heat roller.
6 Lower separation pawl Mechanically separates paper which was not naturally separated from the fusing roller (pressing).
7 Fusing cleaning roller Cleans the fusing roller (pressing).
FUMPCU