An image forming apparatus such as a laser beam printer or an ink-jet recording apparatus has a recording head which records an image on a recording medium in the direction of main scan in accordance with image signals. The recoding medium is moved relative to the recording head in a sub-scan direction substantially perpendicular to the direction of the main scan. A controller controls conditions of recording performed by the recording head so as to effect a correction of recording density unevenness cause by a variation of the relative speed of movements of parts of the apparatus.