Toshiba 4580, Service Manual

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Mar. 1999 © TOSHIBA TEC 14 - 1 6570/5570 FUSER UNIT
14. FUSER UNIT
14.1 General Description
Heat and pressure are applied to fuse the toner to the paper, which is separated from the drum after the
transfer process. After fusing, the paper exits onto the copy receiving tray through the paper-exit unit.
The fuser unit comprises the heater lamps, upper heat roller, lower heat roller separation claws, clean-
ing roller 1, 2, 3, 4, thermistor, thermostat, exit rollers, and exit switch, etc.
14.2 Description of Operation
(1) Fuser
Heat and pressure are applied to the transfer paper that is separated and transported on top of the
drum to fuse the toner.
The upper and lower heat rollers are rotated by drive from the heat roller motor at a constant pres-
sure applied by spring force. The upper heat roller has two built-in heater lamps and rotates by
motor drive. The built-in heater lamps do not rotate. The upper and lower heat rollers are pressu-
rized by spring force at all times.
After fusing is completed, the transfer paper is separated smoothly from the upper and lower heat
rollers by the separation claw. In the temperature sensing section, the temperature of the upper and
lower heat rollers is controlled by a thermistor. If the temperature becomes abnormally hot, the
power to the heater lamps is cut by a thermostat.
Fig. 14.1-1
Upper thermistor
Thermostat
Heater lamp
Discharge brush
Lower thermistor
Cleaning roller 3
Cleaning roller 4
Lower heat roller
Lower separation claw
Upper separation claw
Cleaning roller 1 Cleaning roller 2
Upper heat roller
Exit switch
Heat roller guide
Exit roller