Fuser Unit - Toshiba 8070 Service Manual

14. FUSER UNIT

14.1 General Description
Upper separation claw
Exit roller
Exit switch
Lower separation claw
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.
Mar. 1999 © TOSHIBA TEC
Cleaning roller 1
Cleaning roller 4
Lower heat roller
Fig. 14.1-1
14 - 1
Cleaning roller 2
Upper heat roller
Upper thermistor
Thermostat
Heater lamp
Heat roller guide
Discharge brush
Lower thermistor
Cleaning roller 3
6570/5570 FUSER UNIT