IMAGE FORMING APPARATUS

To allow appropriate heating of a fixing unit regardless of the magnitude of power supply voltage.SOLUTION: An image forming apparatus 1 comprises: a fixing unit that has a heater 33A with high heat generation efficiency, a heater 33B with low heat generation efficiency, and a heating roller 31 having the heaters 33A, 33B as heat sources, and heats a toner image with the heating roller 31 to fix the toner image to a recording medium; a supply switching unit 41 that supplies power 40 to any one of the plurality of heaters 33A, 33B; a voltage detection unit 42 that detects power supply voltage; and a control unit 100 that controls the drive of the supply switching unit 41 based on the power supply voltage detected by the voltage detection unit 42, when the power supply voltage is larger than a predetermined reference voltage, supplies the power 40 to the heater 33B with low heat generation efficiency, and when the power supply voltage is not larger than the predetermined reference voltage, supplies the power 40 to the heater 33A with high heat generation efficiency.SELECTED DRAWING: Figure 3 【課題】電源電圧の大きさに拘わらず、定着部の適切な加熱を可能にする。【解決手段】画像形成装置１は、発熱効率の高いヒーター３３Ａと、発熱効率の低いヒーター３３Ｂと、ヒーター３３Ａ，３３Ｂを熱源とする加熱ローラー３１と、有し、加熱ローラー３１によりトナー像を加熱して記録媒体に定着させる定着部と、複数のヒーター３３Ａ，３３Ｂのいずれかに電源４０を供給する供給切換部４１と、電源電圧を検出する電圧検出部４２と、電圧検出部４２が検出した電源電圧に基づいて、供給切換部４１の駆動を制御し、電源電圧が予め定められた基準電圧より大きいとき、発熱効率の低いヒーター３３Ｂに電源４０を供給し、電源電圧が予め定められた基準電圧より大きくないとき、発熱効率の高いヒーター３３Ａに電源４０を供給する制御部１００とを備える。【選択図】図３