Patent ID: 7583910

Claim:
An image forming apparatus, comprising: an image forming section for forming a color image and a monochromatic image by providing a toner image to a recording sheet; a fixing section for fixing the toner image on the recording sheet at a predetermined fixing temperature, the fixing section being a part of the image forming section; a temperature detector for detecting a temperature of the fixing section; an auxiliary power source for auxiliarily supplying electric power to heat the fixing section, the auxiliary power source being charged with electric power supplied from a commercial power source; a heating portion for heating the fixing section, the heating portion including: a first fixing heater for heating the fixing section by electric power supplied from the commercial power source; and a second fixing heater for heating the fixing section by electric power supplied from the auxiliary power source; a determining section for determining which of a color image and a monochromatic image the image forming section forms; and a controller for controlling electric power supply to the heating portion, wherein when the temperature of the fixing section detected by the temperature detector is less than the predetermined fixing temperature, the controller allows the auxiliary power source to stop supplying electric power to the second fixing heater and allows the commercial power source to supply electric power to the first fixing heater to heat the fixing section when the determining section determines that the image forming section forms a color image, and the controller allows the commercial power source to supply electric power to the first fixing heater to heat the fixing section and allows the auxiliary power source to supply electric power to the second fixing heater to heat the fixing section when the determining section determines that the image forming section forms a monochromatic image.