e-STUDIO160/200/250 FUSER UNIT/EXIT UNIT 14 - 4 December 2002 TOSHIBA TEC
14.5 Functions of Each Part
14.5.1 Fuser unit
(1) Heater lamp
The halogen lamps are provided inside the heater roller to heat the heater roller. The heater lamp
stays fixed even when the heat roller is rotating.
(2) Heater roller
The heater roller is made of aluminum having comparatively good heat conducting properties. It is
heated by the heater lamps. Fusing is carried out by passing the transfer paper through the section
where the heater roller and pressure roller each other so that the toner image on the paper faces the
heater roller. In other words, the toner is melted by the heat of the heater roller, and the heat transfer
efficiency is improved by the pressure of the pressure roller so that the toner soaks in between the
fibers of the paper.
(3) Pressure roller
The pressure roller is made of rubber to facilitate pressurization of the heater roller. The pressure
roller is pressed against the heater roller by springs.
(4) Separation claws
The separation claws separate the paper affixed to the heater roller.
(5) Cleaner fuser roller
The cleaner fuser roller is attached so as to contact the pressure roller to remove the toner and paper
scraps that have stuck to the heater roller during the fusing the process.
(6) Heater thermistor 1 (center section)
The thermistor detects the temperature of the heat rollers so that it is maintained within a fixed
temperature width, (actually, around 200°C), i.e. higher than the lower limit (defective fusing
temperature) and the upper limit (toner burning temperature). In other words, the thermistor controls
the temperature so that the heater lamps turn ON when the heater roller is low than the temperature
setting, and turn OFF when they are above the temperature setting.
(7) Heater thermistor 2 (end section)
The temperature distribution of the heater roller sometimes differs greatly at the center section and
end section in the lengthwise direction depending on the printing conditions. The thermistor 2 detects
the temperature at the end section. This thermistor controls the temperature so that the heat lamp
turns OFF when either of the values detected by the thermistor 1 or thermistor 2 exceeds the tem-
perature setting.
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