Patent ID: 8693910

Claim:
An image forming apparatus comprising: an image forming unit configured to form an unfixed image on a recording material; a fixing unit including an endless belt, a heater held in contact with an inner surface of the endless belt, a pressurization roller configured to form a fixing nip portion for pinching and conveying the recording material together with the heater via the endless belt, and a pressure changing mechanism configured to effect switching between a pressurization state in which a pressure, at a time of fixing processing, is applied to the fixing nip portion and a pressure release state in which the pressure applied to the fixing nip portion is released; a first temperature detection element configured to detect an endless belt temperature of the endless belt; a second temperature detection element configured to detect a heater temperature of the heater; and a power control unit configured to control a supply of power to the heater, wherein, in response to a print signal being input to effect transition from the pressure release state to the pressurization state, the power control unit starts the supply of power to the heater during a transition period before the pressurization state is attained and controls the supply of power to the heater such that a heater temperature does not exceed a predetermined upper limit temperature during the transition period, and wherein the power control unit controls the supply of power to the heater according to the heater temperature detected by the second temperature detection element until the heater temperature attains a target temperature at the time of fixing processing, and controls the supply of power to the heater according to the endless belt temperature detected by the first temperature detection element after the heater temperature has attained the target temperature.