Patent ID: 7777767

Claim:
An image forming apparatus comprising: an image forming unit that forms a color image in which a plurality of color component images are superimposed; a formation controlling unit that allows the image forming unit to form, in a predetermined direction, a plurality of images for adjustment of formation positions of the respective color component images, wherein the formation controlling unit allows the image forming unit to form, for each color, a plurality of adjustment images having different tilts with respect to the predetermined direction; a first calculating unit that calculates a shift of a detected position of each adjustment image from a reference position in which each adjustment image should be formed; a second calculating unit that calculates a tilt and an intercept of a regression line that uses the reference positions and the calculated shifts as variables; and a third calculating unit that calculates a shift in a main scanning direction and a shift in a sub-scanning direction based on the calculated tilt and intercept.