Toshiba 4511, 3511 manual Heating principle of IH Heater, Image of Current Flowing form a to B

16.4.2 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 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.

Main IH coil Current flowing on the surface of the fuser roller

B

High frequency power source

A

Sub IH coil	Magnetic field Eddy current	Current flowing inside the
		fuser roller

[Image of Current Flowing form A to B]

Fig. 16-402

Control circuit high frequency current

		Fuser roller
		IH coil
Smoothing circuit		Tr1
	C2	IGBT
		drive
	C3	(IGBT)
		Tr2
C1
		IGBT
D1		drive
T1
Current input
CPU		Photocoupler
Monitoring input current
Voltage
input
		I/F circuit on LGC board
Monitoring input current

[Book Diagram of High Frequency Power Supply]

Fig. 16-403

16

November 2003 © TOSHIBA TEC 16 - 5 e-STUDIO3511/4511 FUSER UNIT/PAPER EXIT SECTION