Patent ID: 7548333

Claim:
A data transfer method in an image formation system which is equipped with an image generation controller unit for generating bitmap image data of an image, an image formation unit for forming an image on a recording medium, an image processing controller unit for controlling the image formation unit and for transferring image data at a timing requested by the image formation unit, and respective data signal lines for yellow, magenta, cyan and black to be used to transfer the image data between the image generation controller unit and the image processing controller unit, wherein in a case where the number of image bearing bodies of the image formation unit is one, when a color image signal is transferred from the image generation controller unit to the image processing controller unit, the image signals of one color component for the four lines are simultaneously transferred by using the yellow, magenta, cyan and black signal lines repeatedly until the transfer of the image signals for one page ends, and then the image signals of the next color component are transferred, when a tag signal is added to a pixel of the color image signal, neighboring pairs of pixels are handled as a set of pixels to reduce the resolution, whereby the image formation can be performed with an increased gradation, wherein the tag signal represents a photograph image area, and when a black-and-white image signal is transferred from the image generation controller unit to the image processing controller unit, the image signals of black color component are simultaneously transferred by using the yellow, magenta, cyan and black signal lines, wherein the black-and-white image signal is a binary signal and has a higher resolution than the color image signal.