IMAGE FORMING APPARATUS AND CONTROL METHOD OF THE SAME

PROBLEM TO BE SOLVED: To solve the problem that conventional correction is performed on whole scan lines and that a difference of contraction in each region due to an optical characteristic and the like is not considered.SOLUTION: One main scan line is divided into a plurality of regions and a first image with the first number of pixels is formed in each region and a second image with the second number of pixels different from the first number of pixels is formed in each region. A contraction rate of the image at every region is obtained based on a size difference between the first image and the second image, which are thus formed, and a difference between the first number of pixels and the second number of pixels (S14). The number of pixels added or deleted at every region is decided (S16) in accordance with the number of pixel corrections per main scan line (S15) and the obtained contraction rate. Image data formed in each region is corrected in accordance with the number of pixels, which is thus decided (S17).