Patent ID: 8185005

Claim:
An image forming apparatus comprising: an image carrier; a plurality of forming devices configured to form an image; and a processor configured to operate as a detecting device configured to perform a steady-deviation detection and a varying-deviation detection, the steady-deviation detection being for detecting steady positional deviation of an image to be formed by the plurality of forming devices, the varying-deviation detection being for detecting varying positional deviation of the image, the varying positional deviation having a cycle; and a correcting device configured to perform a steady-deviation correction and a varying-deviation correction, and selectively enable or disable the varying-deviation correction, the steady-deviation correction being for correcting the steady positional deviation based on the result of the steady-deviation detection, the varying-deviation correction being for correcting the varying positional deviation based on the result of the varying-deviation detection, wherein: the detecting device forms, during the steady-deviation detection, a steady-deviation detection pattern on the image carrier using the plurality of forming devices in a state where the varying deviation correction is disabled; the steady-deviation detection pattern has a plurality of measuring points arranged in a longitudinal direction; and the detecting device, during the steady-deviation detection, measures positional deviation amount at each of the plurality of measuring points, and detects the steady positional deviation based on the measurement result.