According to one embodiment, an image forming apparatus includes a fixing device and a control unit. The fixing device forms an image represented by print data on an image forming medium by causing a part or all of a plurality of heat generating cells to generate heat, and by fixing a developer image corresponding to the print data on the surface of the image forming medium. The control unit corrects image data before correction so as to reduce the number of heat generating cells which are caused to generate heat among the plurality of heat generating cells based upon an arrangement of an image represented by the image data before correction and an arrangement of the plurality of heat generating cells, and uses image data after correction obtained by correcting the image data before correction as the print data.