Service manual

EPSON EPL-5800 Revision B
Operating Principles Operating Principles of Mechanism 55
2.1.7 Fusing Process
2.1.7.1 Overview
!
In this process, toner which is transferred to the paper in the transfer process is
fused to the paper.
!
Fusing system this printer uses is the heat roller fusing system.
The toner passes between the back-up roller and the heat roller, which is heated up
by the heater lamp, and heat and pressure are applied to permanently fuse the toner
to the paper.
Figure 2-11. Fusing Mechanism
2.1.7.2 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, the heater lamp (H1) is turned ON
(light on) and OFF (light off) by the heater lamp ON/OFF signal which is output
by the IC1A-55, and controls the temperature of the fusing components.
!
When the heater lamp is not turned OFF even though the thermistor detects
abnormal high temperature (when the surface temperature of the fusing heat roller
exceeds 210
°
C), the output from IC-79 is changed from L to H and it forcibly turns
the heater lamp OFF.
Figure 2-12. Fusing Temperature Control Circuit
Back-up Roller
Heat Roller
Heater Lamp
(H1)
Front Guide Board
Thermostat
(TS1)
Separating Claw
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Paper
Thermistor
(TH1)
1
2
1
2
PJ2
2
1
TH1
1
2
CN1
H1
TS1
PU1
DC5V
78
IC1
PWB-P
3
2
1
DT1
GND
DC5V
IC2
79
55
CMPOUT
P01
CMPIN/AN8/P63
GND
GND
H1: ON
H1: OFF
L
H
H
L
L
L
1
2
3
PJ7
4
5
1
2
3
4
5
CN2
6
7
6
7
+24V
GND
GND
+5V
FUSER_LAMP
24V_MON
SLEEP_MODE
N.C.
HEAT_N
HEAT_L
3
4121s037