MX-6201N, MX-7001N (serv.man39). FUSING SECTION - Sharp Copying Equipment Service Manual (repair manual). Page 2

MX-7001N  FUSING SECTION  O – 2

To drive the fusing unit, the drive power is transmitted from the
drive motor (FUM) through the connection gear to the upper heat
roller gear.
The drive motor (stepping motor) is driven according to the control
signal sent from the PCU.

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 lighting signal is sent from the PCU
to the heater lamp drive circuit in the sub power 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, power supply (AC line) to the
heater lamp is cut off.

Color toner of YMCK on paper is heated and pressed by the heat
rollers to be fused on paper.
At that time, color toner of YMCK is mixed to reproduce nearly
actual colors of document images.

The heater lamp is provided in the upper and lower heat rollers and
the external heat roller. It heats paper up and down.
This is because necessary to heat from left/right/above/below for
fusing four layers of toner on paper.
The upper and lower heat rollers are of silicon rubber.
This is because of the following reasons:
1)

To provide a greater nip quantity and a higher heating capacity
for paper.

2)

The soft, flexible rollers press multi-layer toner without defor-
mation to fuse on paper.

3)

An even pressure is applied to an uneven surface of multilayer
toner.

The external heat roller roller has the following functions.
1)

Helps fusing and keeps the fusing temperature under special
conditions.

FCFM

Fusing cooling fan

Cools the fusing unit

FEXM

External variable motor

Separates the external heat roller of the fusing unit

FRS

Separation pawl solenoid

Controls separation of the fusing separation pawl

FUM

Fusing motor

Drives the fusing unit

HL_EX

Heater lamp external

Heats the external heat roller

HL_LM

Lower heater lamp

Heats the lower heat roller

HL_UM

Heater lamp upper main

Heats the upper heat roller

HL_US

Heater lamp upper sub

Heats the upper heat roller

POD1

Fusing rear detection

Detects the paper from the fusing unit

TH_EX1

External thermistor main

Controls surface temperature of the external heat roller

TH_EX2

External thermistor sub

Controls surface temperature of the external heat roller

TH_LM

Lower  thermistor

Controls surface temperature of the lower heat roller

TH_UM

Upper  thermistor main

Controls surface temperature of the upper heat roller

TH_US

Upper  thermistor sub

Controls surface temperature of the upper heat roller

TS_EX

External thermostat

Prevents the external heat roller overheating

TS_LM

Lower thermostat

Prevents the lower heat roller overheating

TS_UM

Upper thermostat main

Prevents the upper heat roller overheating

TS_US

Upper thermostat sub

Prevents the upper heat roller overheating

WEB_END

Web end sensor

Detects end of the web

WEBM

Fusing web cleaning motor

Drives the fusing web cleaning paper

1

Upper heat roller

Heat and presses toner on paper to fuse it on paper

2

Lower heat roller

Heat and presses toner on paper to fuse it on paper

3

Upper separation pawl

Mechanically separates the paper which was not separated naturally from the upper heat roller.

4

Lower separation pawl

Mechanically separates the paper which was not separated naturally from the lower heat roller.

5

External heat roller

Supports temperature control of the upper heat roller.

6

Web unit

Clean the upper heat roller

7

Transport roller 9 (Drive)

Transports paper from the upper/lower heat rollers to the paper exit roller 1

FUM

PCU