IMAGE FORMING APPARATUS HAVING IMPROVED POSITION ABERRATION DETECTION

To reduce errors in a detection of pattern images to enable aberrations to be detected accurately. An image forming apparatus includes a plurality of image forming units for forming images of different colors, a moving member moving so as to transfer the images formed by the plurality of image forming units to corresponding transfer locations, a pattern forming unit for controlling the plurality of image forming units so as to form a plurality of pattern images in a direction crossing a movement direction of the moving member so that two pattern images of a predetermined reference color are transferred onto the moving member with one pattern image of a different color transferred therebetween, a pattern detecting unit for detecting the pattern images transferred onto the moving member, and a correction unit for detecting aberration of the image of the different color with respect to the images of the reference color on the basis of an output from the pattern detecting unit and for correcting the aberration of the image of the difference color on the basis of the detected aberration.