Patent ID: 7684723

Claim:
An image forming apparatus having a first function for forming an image received by facsimile, and a second function for forming an image other than the image received by the facsimile, the apparatus comprising: an image forming unit configured to form a toner image on a sheet; a fixing device configured to fix the toner image to the sheet; a main power circuit configured to supply electric power for operating the image forming apparatus; an auxiliary power circuit configured to store the electric power and supply the stored electric power for operating the image forming apparatus; a switching device configured to switch between a charge mode for charging the auxiliary power circuit and a discharge mode for discharging the stored electric power in the auxiliary power circuit; and a control device configured to, when the image is formed on the basis of the first function, control the switching device so as to operate the auxiliary power circuit not in the discharge mode so that the electric power of the main power circuit is supplied to the fixing device, and when the image is formed on the basis of the second function, control the switching device so as to operate the auxiliary power circuit in the discharge mode so that the electric power of the main power circuit and that of the auxiliary power circuit are supplied to the fixing device.