Patent ID: 8743415

Claim:
An image forming apparatus comprising: a plurality of image forming units, each of the plurality of image forming units including a photosensitive member configured to rotate in a sub scanning direction and a developing unit configured to develop a latent image formed on the photosensitive member and form a toner image; an exposure unit configured to emit a light beam, with which the photosensitive member is to be scanned in a main scanning direction intersecting the sub scanning direction; an image bearing member onto which the toner images formed on the photosensitive members are to be transferred; a correcting unit configured to correct, in the sub scanning direction, image data based on a first correction condition corresponding to a distortion characteristic of a scanning line of the light beam emitted from the exposure unit; and a detecting unit configured to detect a pattern image transferred at a predetermined position of the image bearing member in the main scanning direction, wherein, the correcting unit corrects pattern image data indicating the pattern image based on a second correction condition different from the first correction condition so that a distortion amount of the pattern image at the predetermined position becomes less than or equal to ½ scan line distance.