Read Sharp AR-651 (serv.man17) Service Manual online
AR-651/810 FUSER UNIT 14 - 5
D1
T1
C1
C3
CPU
Tr2
(IGBT)
IGBT
drive
C2
Tr1
IGBT
drive
14. 4. 2. Heating principle of IH coil
The magnetic field is generated by applying a high frequency current to the IH coil inside the fuser roller,
which then produces the eddy current in it. When the eddy current flows, the Joule heat is generated by the
resistance element of the fuser roller, which is then heated. In the IH coil method, the thermal efficiency is
higher than the lamp method because the fuser roller is directly heated.
IH coil is divided into two parts to decrease the temperature difference between the center and both ends
of the fuser roller.
Current flowing inside the
fuser roller
fuser roller
[Block diagram of high frequency power supply (IH control board)]
IH coil
Fuser roller
Monitoring input current
Monitoring input current
Current input
Voltage
input
input
I/F circuit on LGC board
Photocoupler
Smoothing circuit
Control circuit for high frequency current
[Image of current flowing from A to B]
Current flowing on the surface of the fuser roller
High frequency
power source
power source
Side IH coil
Magnetic field
Eddy current
B
A
Center IH coil
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