Patent ID: 7366435

Claim:
A fixing controller comprising: a main control circuit that includes a main central processing unit configured to control all operations of an image forming apparatus; a temperature sensor configured to detect a temperature of a fixing member; an excitation coil configured to receive a current supply and inductively heat the fixing member; and an induction-heating control circuit that includes a sub central processing unit independent of the main central processing unit and that is configured to control current supplied to the excitation coil, wherein the main central processing unit is configured to send a desired power signal as a control instruction to the sub central processing unit, based on the temperature detected by the temperature sensor, the sub central processing unit is configured to control current flowing in the excitation coil based on the desired power signal sent by the main central processing unit, a sensed voltage, and a sensed current, and the main central processing unit periodically acquires the temperature of the fixing member detected by the temperature sensor, and, in accordance with the temperature, switches output control cycles of the desired power signal sent to the sub central processing unit, when the temperature acquired is close to a target temperature, the main central processing unit outputs the desired power signal in a short control cycle, and, when the temperature acquired is far from the target temperature, the main central processing unit outputs the desired power signal in a long control cycle, which is longer in duration than the short control cycle.