Specifications

EPL-5700 Chapter2 Operating Principles
Rev. A
2-11
2.1.9 Fusing Process
2.1.9.1 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 on the paper is melted by pressure from the
paper traveling through the back up roller and the heat roller, which is
heated up by the heater lamp. The heat roller is mounted at 200M Ω. This
prevents the transfer current from leaking along with the paper(electrostatic
offset).
200Mohm
Paper
Back-up roller
Heat roller
Heater lamp
Thermister
Thermostat
Front
g
uide board
Seperatin
g
claw
Figure 2-13. Fusing Mechanism
2.1.9.2 Fusing Temperature Control Circuit
The thermister (TH1) detects the surface temperature of the fusing heat
roller, and input analog voltage into IC201-78. According to the detected
temperature, the heater lamp (H1) is turned On or Off by the heater lamp
On/Off signal, which is input by IC201-55, and controls the temperature of
the fusing part.
The heater lamp is 450W. 3 different voltages are used according to the
destination; 100V, 120V and 230V.
If the heat lamp is not turned off even when the thermister detects
abnormally high temperature, thermostat turns off the heater current as
soon as the temperature of the heat roller reaches 195 °C, and prevents the
heat roller from increasing its temperature.
1
2
1
2
CN202
2
1
TH1
1
2
3
CN207
4
5
1
2
3
4
5
CN1
GND
GND
+5V
FUSER_LAMP
1
2
CN2
N.C.
HEAT_N
3
HEAT_L
H1
TS1
DC5V
78
IC201
3
2
1
Q201
GND
DC5V
IC202
79
55
CMPOUT
P01
CMPIN
GND
GND
Heater Lamp
Thermostat
Thermistor
H1: ON
H1: OFF
L
H
H
L
L
L
+24V
Power Supply Board
Relay Connector
Main Control Board
CN1
Figure 2-14. Fusing Temperature Control Circuit
When the power switch is turned on, warm-up starts after the printer
performs initialization, then, the heater lamp is turned on. The heater lamp
stays On until the temperature of the heat roller reaches about 185 °C, and
the following temperature controls are performed.
Temperature control mode1
This mode controls the temperature to maintain 185 °C during printing and
105 °C during waiting mode. This mode goes to mode2 after 45 seconds.