Patent ID: 7650090

Claim:
An image forming apparatus, comprising: a fusing device for heating a heating body with supplied power to fuse developer onto a printing medium; a power supply unit for supplying the power to said fusing device; a temperature detection unit for detecting a temperature of said fusing device; a fusion control unit for controlling the power supplied to said fusing device from said power supply unit based on a detection result of said temperature detection unit; an input unit, electrically isolated from said power supply unit, for receiving a control current for controlling the power supplied to said heating body from said power supply unit; and an output unit, electrically isolated from said power supply unit, for outputting the control current received by said input unit, wherein said fusion control unit comprises: a control current output unit for outputting the control current to said input unit; a control current input unit for receiving the control current output from said control current output unit; a control current output control unit for controlling the control current output by said control current output unit based on the detection result of said temperature detection unit; and a control current input control unit for controlling the control current received by said control current input unit based on the detection result of said temperature detection unit.