Patent ID: 6885841

Claim:
An image forming apparatus comprising: a plurality of image carriers on which images are formed based on image data; a transfer carrier on which different color component images formed on said respective image carriers are superimposed sequentially with a movement of said transfer carrier in a sub-scanning direction; a position changing section for changing a superimposing position of the different color component images; a density detecting section for detecting a density average value of each combined image formed by superimposing the different color component images, for a plurality of combined images formed by superimposing the different color component images at respectively different positions; and a position determining section for determining a superimposing position of the different color component images, based on detection results of said density detecting section, wherein each of the plurality of combined images is formed separately for each image carrier with respect to a length related to a circumference length of the image carrier, and said image forming apparatus comprises a combined-image adjusting section for forming a combined image so that said density detecting section detects a density of the combined image at plural and substantially equal pitches within a range of at least one circumference length of said image carrier, or so that said density detecting section detects a density average value of the combined image at plural and substantially equal pitches within a range of at least one circumference length of said image carrier.