Electric Circuit Description - Toshiba e-STUDIO 2555C Service Manual

3.16.3

Electric Circuit Description

[ 1 ] Fuser unit control circuit
[ 1-1 ] Configuration
This equipment employs an external IH coil unit for heating the fuser belt. IH coils in the IH coil unit
generate a magnetic field to heat the fuser unit with a high-frequency current carried inside of them.
The surface temperature of the fuser belt is detected with the center, edge, and side thermistors.
The detected temperature data are sent to the ASIC. Based on the received temperature data, the
ASIC then controls the electricity of the IH coils. When the surface temperature of the fuser belt
exceeds the preset temperature, the forcible power OFF circuit sends a power supply relay OFF signal
as well as an overheating signal to the ASIC, and then shuts OFF power supply over all parts except
the control panel.
If the circuit noted above does not operate due to problems such as thermistor malfunction and
therefore the fuser belt is abnormally heated, the thermostat shuts OFF power supply to the IH coils to
protect the equipment.
Switching regulator
Fuse
Ｌ
FIL
board
Ｎ
e-STUDIO2555C/3055C/3555C/4555C/5055C
OUTLINE OF THE MACHINE
Main switch
Relay
Fuse
AC/DC
Converter
Interlock switch
AC line
DC line
Fig. 3-48
IH
drive circuit
Control circuit
Edge
thermistor thermistor
Rotation Contact/Release
detection sensor detection sensor 2
IH coil energization permitting signal
Switching signal of power setting
IH status signal
Forcible power-off
circuit
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3 - 80
IH coil
Fuser belt
Contact/Release
Side Center New/Old
Fuser unit
detection sensor 1
thermistor detection
ASIC
LGC board