An image forming apparatus includes DMA control units each of which is provided with DMA controllers. Each DMA controller is provided with a plurality of data buffers respectively corresponding to different addresses in a subscanning direction. Each of a predetermined number of pixel data in a main scanning direction is stored in an associated one of the data buffers. Pixel data stored in each of the data buffers are output to an image memory based on the address in the subscanning direction, which corresponds to the associated data buffer.