IMAGE FORMING DEVICE TO SUPPLY DC POWER TO A LOAD FROM BOTH A MAIN POWER SUPPLY DEVICE AND A CAPACITOR SUPPLY DEVICE

Stored DC power is supplied to a load after a return to a normal-power mode or a power-up of an image forming device. An auxiliary power supply does not supply the stored DC power to the load, and a main power supply supplies AC and DC power to the load if it is determined that a predetermined processing is performed upon a starting of the image forming device. The auxiliary power supply supplies the stored DC power to the load, it is determined whether a predetermined time has elapsed, and the main power supply does not supply the AC and DC power to the load if it is determined that the predetermined processing is not performed upon the starting of the image forming device. A decision whether the predetermined processing is performed is based on at least one of a number of sheets, an elapsed time, and an environmental temperature.