Fusing Process - Epson EPL-5900 Service Manual

EPSON EPL-5900/EPL-5900L

2.2.7 Fusing Process

OVERVIEW
In this process, the toner transferred to the paper in the transfer process is fused to the paper.
For fusing, this printer uses the heat roller fusing system. The sheet with toner on passes
between the heat roller, which is heated up by the heater lamp, and the back-up roller.
During this passage, heat and pressure are applied to permanently fuse the toner to the
paper.
FUSING TEMPERATURE CONTROL CIRCUIT
The thermistor (TH1) detects the surface temperature of the fusing heat roller and inputs the
analog voltage to IC1A-78. Based on the thermistor detected temperature, IC1A-55 outputs
the heater lamp ON/OFF signal. According to this signal, the heater lamp (H1) turns ON
(lights up) and OFF (goes out) to control the temperature of the fusing components.
If the heater lamp does not turn OFF even when the thermistor detects too high temperature
(when the surface temperature of the fusing heat roller exceeds 250°C), the output from IC-
79 changes from L to H and forcibly turns the heater lamp OFF.
Operating Principles
Paper
Fusing
Separation
Claw
Thermostat
(TS1)
Thermistor
(TH1)
Heater Lamp (H1)
Heat Roller
Figure 2-17. Fusing Temperature Control Circuit
Description of Mechanisms
Front Fusing Guide
Figure 2-16. Fusing Mechanism
Revision B
Backup Roller
73