Patent ID: 7580661

Claim:
An image formation device comprising: a plurality of image formation sections, each image formation section that forms a predetermined single-color image so as to be superposed with another single-color image on the image-bearing body and forms a pattern image for positional offset detection on the image-bearing body, the pattern image being formed at a non-image creation region outside an image creation region at which the output image is formed; a pattern image detection section that detects positions of the plurality of pattern images which are respectively formed at the non-image creation region by the plurality of image formation sections, and generates position detection data corresponding to the positions of the plurality of pattern images; and a registration correction section that, on the basis of the position detection data, detects a relative positional offset amount between the plurality of single-color images forming the output image, and carries out correction in a stepwise manner in which a positional offset correction for the relative positional offset with respect to the image formation section, at which the relative positional offset exceeding a predetermined threshold value occurs, is divided into a plurality of positional offset corrections so as to carry out the divided plurality of positional offset corrections for the respective divided relative positional offsets stepwisely, or in a continuous manner in which the positional offset correction for the relative positional offset with respect to the image formation section, at which the relative positional offset exceeding the predetermined threshold value occurs, is carried out continuously gradually over a predetermined range, for the relative positional offset exceeding a predetermined threshold value.