Patent ID: 8311424

Claim:
An image forming apparatus comprising: a fixing roller to fix a toner on a printing medium; an alternating current (AC) power source to supply an AC electric power; a power converting part to convert the AC electric power from the AC power source to a high frequency power for induction heating; a heater to heat the fixing roller, the heater is adapted to be heated by an induction heating according to the converted high frequency power output from the power converting part; a relay including a first relay contact point disposed on a first AC power supply line between the AC power source and the power converting part and a relay coil to open and close the first relay contact point, the relay selectively supplying the AC electric power from AC power source to the power converting part; a direct current (DC) power supplier to supply a DC power to the relay coil; and a DC thermoswitch coupled between the DC power supplier and the relay coil to control supply of the AC electric power from the AC power source to the power converting part according to an overheating of the fixing roller.