A color printer includes a single laser scanning unit which is controlled to emit a scanning laser in accordance with color image data on each of a plurality of separated colors to be printed. A plurality of photosensitive drums, whose number corresponds to the number of colors to be printed, a laser scanning unit driver which moves the laser scanning unit to transfer positions corresponding to the photosensitive drums, and a plurality of developing units corresponding to the photosensitive drums are provided, to develop latent images drawn on the photosensitive drums by the laser emitted from the laser scanning unit, using a toner of each color. An endless transfer belt has a transfer surface which is successively moved to the transfer positions, and a transfer device which successively transfers the toner images developed by the developing units on the photosensitive drums, onto the same transfer surface of the transfer belt are also provided.