Heating Principle Of Ih Coil - Toshiba e-STUDIO555 Service Manual

13.4.2

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.
Image of current flowing from A to B
High frequency
power source
Block diagram of IH board
e-STUDIO555/655/755/855
FUSER UNIT
Center IH coil
B
A
Side IH coil High frequency
magnetic field
Fig. 13-3
Ripple filter circuit
C2
D1
T1
Input current
Monitoring input current
Monitoring input voltage
Fig. 13-4
13 - 4
Current flowing on the surface of the fuser roller
Eddy current Current flowing inside the fuser roller
Control circuit for high frequency current
Fuser roller
IH coil
Q1
C1
IGBT
driver
( IGBT )
Q11
C31
IGBT
driver
CPU
Input
voltage
I/F circuit for LGC board
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