Patent ID: 7356274

Claim:
A method for forming a color image in which a number of color toner images are superposed together by using an intermediate transfer medium, comprising: forming a plurality of electrostatic images corresponding to image data; developing each of electrostatic images by supplying toner of a predetermined color to said each electrostatic image; successively transferring toner images having different colors onto a predetermined position on an intermediate transfer medium, and holding the toner images, on one of effective image holding regions of the intermediate transfer medium, after at the point in time when output-image data on a first color, which corresponds to one of the effective image holding regions are compiled, an electrostatic image for said one of the effective image holding regions is formed on the image forming section, is developed at the developing section, and is transferred as a toner image to the toner image holding section, and when the output-image data for the electrostatic image for the other effective image holding region is not compiled, at the point in time when output-image data on a second color, which corresponding to said one of the effective image holding regions, are complied, an electrostatic image for said one of the effective image holding regions is formed on the image forming section, is developed at the developing section, and is transferred as a toner image of a second color to the toner image holding section; and transferring the toner images from the intermediate transfer medium to a transfer medium such that the toner images are superposed on each other on the transfer medium.