Patent ID: 8339656

Claim:
An image forming apparatus comprising: a plurality of image forming units configured to form, by scanning lines of light in a main scanning direction according to image data, a latent image of a respective color on a photosensitive member that rotates in a sub scanning direction, develop the latent image on the photosensitive member in the respective color, and transfer the image developed on the photosensitive member to an image bearing member; a storage unit configured to store a displacement amount of the scanning line of at least one of the plurality of image forming units in the sub scanning direction with respect to a reference line; and a correcting unit configured to correct, in the sub scanning direction, image data of a pattern image for determining a positional displacement between the images formed by the plurality of image forming units, in accordance with the displacement amount stored in the storage unit so that a displacement amount in the sub scanning direction of the pattern image with respect to the reference line at a determination position for determining the positional displacement in the main scanning direction of the pattern image becomes less than or equal to ½ of a distance between neighboring scanning lines, when the image forming unit forms the pattern image.