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11. IMAGE TRANSFER
Image transfer is the process of transferring the toner image created
on the PC Drum in the developing process to paper. We use the
Roller Image Transfer instead of the Corona Image Transfer, as the
image transfer method. In the Roller Image Transfer, there is little
generation of ozone due to corona discharge. Also, there is no blur of
toner because the paper is always pressed by the PC Drum and the
Image Transfer Roller.
When cleaning the Image Transfer Roller and before printing, reverse
bias is applied.
12. FUSING
12-1. An Overview
The toner image transferred onto the paper is securely fixed.
A heat roller system is used as the fusing system. The toner image is
fused by the Upper Fusing Rokkellheated by the Heater Lamp, and
securely fixed by the pressure between the Upper and Lower Fusing
Rollers.
A Thermistor (TH1) detects and conttrols the Upper Fusing Roller
temperature.
The Thermostat (S3) blows when the temperature becomes approx.
133˚C and shuts down the power to the Heater Lamp.
Paper
Image
Transfer
Roller
Sequential Bias
approx. 6 - 16 µA
Reverse Bias
approx. -900V
PWB-A
IC1
77
IC2
H
L
54
2
3
H
IC2
5
75
6
L
H
Lower Fusing Roller
PC Drum
PWB-F
8
1
CN1
Fig. 12
12-2. Fusing Temperature Control Circnit
The Thermistor (TH1) detects the surface temperature of the Upper
Fusing Roller and inputs that analog voltage into IC1A-77. Corre-
sponding to this data, the Heater Lamp ON/OFF signal is output from
IC1A-54, causing the Heater Lamp (H1) to turn ON or OFF to control
the fusing temperature.
When the Heater Lamp is not turned OFF even if the Thermistor
detects a high temperature malfunction (if the surface temperature of
the Upper Fusing Roller exceeds 200˚C), the signal from IC1A-75
changes from H to L to turn OFF the Heater Lamp forcibly.
Analog voltage detected by the
Thermistor (TH1)
CN2
1
DC5V
2
IC3
CN7
1
4
3
1
1
H
L
Power
PWB
5
5
CN1
Heater Lamp ON/
OFF Signal
L H1 : ON
H
H1 : OFF
Thermostat
Thermistor
Upper Fusing Roller
Heater Lamp
paper
Fig. 13
3 – 8
PWB-A
CN4
1
8
TH1
Thermistor
Heater Lamp
CN2
1
H1
2
3
S3
Thermostat
FO-4500H
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