Patent ID: 8139964

Claim:
A fixing device, comprising: a heater; a heating body that is heated by heat generated by the heater and is caused to rotate; a pressure body that is in contact with the heating body, forms a nip through which a sheet having a toner image transferred thereonto enters, and is caused to rotate; a plurality of temperature sensor units each including a temperature sensing element that is covered with a protective member and is in contact with the heating body in order to sense a temperature of the heating body; and a control unit that is configured to: recognize temperatures of the heating body at respective portions thereof based on signals received from the plurality of temperature sensor units; judge that a failure has occurred if the temperatures are different from each other by a fixed value or larger; bring the heater into an ON state if the recognized temperatures exhibit a temperature difference of a predetermined value or larger, and then judge that the protective member has peeled off if all the temperatures sensed by using the plurality of temperature sensor units are recognized to have risen; and correct the recognized temperature sensed by using one of the plurality of temperature sensor units that has been determined to have the protective member peeled off.