Patent ID: 8010007

Claim:
An image forming apparatus comprising: a fixing device to fix a toner image formed on a medium by applying pressure and heat onto the medium, the fixing device including a plurality of heating units having different power consumptions; a power supplying unit to supply a power to each of the plurality of heating units; and a control unit to control a supply of the power to the plurality of heating units by the power supplying unit at a control period T 1 , the control unit including, a first unit to set the control period T 1 , a second unit to set a power supply time t 1 for a first heating unit having a largest power consumption among the plurality of heating units to which the power is supplied within the control period T 1 and a power supply time t 2 for a second heating unit having a second largest power consumption of the plurality of heating units, a third unit to supply the power to the first heating unit for a first period of the power supply time t 1 , the first period being from a beginning of the control period T 1 , and to supply the power to the second heating unit for a second period, the second period being from a point obtained by subtracting the power supply time t 2 from an end of the control period T 1 , a fourth unit to set a power supply time t 3 for a third heating unit, the third heating unit having a power consumption third largest next to the second heating unit, and a fifth unit to determine a point tc to start a supply of the power to the third heating unit such that at least one of the power supply time t 3 does not overlap with both power supply time t 1 and power supply time t 2 within the control period T 1 and minimizing the overlap of the power supply time t 3 with both power supply time t 1 and power supply time t 2 within the control period T 1 .