Heating Principle Of Ih Heater - Toshiba e-STUDIO281c Service Manual

16.5.2

Heating principle of IH Heater

The magnetic field is generated by applying a high frequency current to the IH coil inside the fuser
roller, which then generates the eddy current in it. When the eddy current flows, the Joule heat is gener-
ated by the resistance element of the fuser roller, which is then heated. In the IH coil method, the ther-
mal 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 form A to B
High frequency
power source
Block diagram of IH board
June 2005 © TOSHIBA TEC
Main IH coil
B
A
Sub IH coil Magnetic field
Fig.16-3
Smoothing circuit
C1
D1
T1
Current input
CPU
Monitoring input current
Voltage
input
Monitoring input current
Fig.16-4
16 - 7
Current flowing on the surface of the fuser roller
Eddy current Current flowing inside the
fuser roller
Control circuit high frequency current
Fuser roller
IH coil
Tr1
IGBT
C2
drive
( IGBT )
C3
Tr2
IGBT
drive
I/F circuit on LGC board
e-STUDIO281c/351c/451c FUSER UNIT / PAPER EXIT SECTION
16