Patent ID: 7577373

Claim:
An image forming apparatus comprising: a conveyance motor for conveying paper; an image forming unit forms a toner image on the conveyed paper; a fixing device having a heat roller including plural heat sources and a pressure roller disposed facing the heat roller, the fixing device causing the toner image to be fixed to the paper; a control unit generates first control signals that switch ON or OFF the plural heat sources and a second control signal that controls the driving of the conveyance motor, and generates a mode signal that differs between a warm-up mode and a normal mode; and a first control circuit including: a first AND circuit to which the first control signals for separately switching ON the plural heat sources are inputted, a second AND circuit to which the mode signal and an output signal of the first AND circuit are inputted, and a third AND circuit to which the second control signal that controls the driving of the conveyance motor and the mode signal are inputted, wherein the supply of the first control signals to the plural heat sources is controlled by the output of the second AND circuit and the supply of the second control signal to the conveyance motor is controlled by the output of the third AND circuit, wherein the first control circuit switches ON the plural heat sources at the same time and prohibits the driving of the conveyance motor during the warm-up mode, and allows the driving of the conveyance motor and prohibits all of the plural heat sources from being switched ON at the same time during the normal mode.