IMAGE DATA TRANSFER METHOD FOR IMAGE FORMING DEVICE

PURPOSE:To improve picture quality by transferring all the image data for one line to the same line memory before the end of a one-line next to a certain one-line period when all the image data are not transferred. CONSTITUTION:A DMA transfer control block 2 fetches image data from a frame memory 1 and transfers the lines of image data one by one while basically alternately switching two line memories 3 and 4. When the generation of DMA non-transfer in a Super Fine mode or an Ultra Fine mode is recognized at a CPU 8, the image data of lines generating the DMA non-transfer over two line periods are transferred. On the other hand, at a resolution converting device 5, the image data of the same line are transmitted to a printer part 6 while converting the resolution continuously twice. Then, during next one line period, the image data of the second line from the line, where the DMA non-transfer is generated, are transferred.