Patent ID: 7936368

Claim:
An image forming method for forming a multiple-color image using a plurality of photosensitive bodies, each of the photosensitive bodies of the plurality of photosensitive bodies corresponding to a different color, the method including exposing the photosensitive bodies to a plurality of scanning beams, each of the scanning beams of the plurality of scanning beams corresponding to one of the photosensitive bodies of the plurality of sensitive bodies, the method comprising: measuring positional displacements of each of the scanning beams of the plurality of scanning beams in a sub-scanning direction to obtain measurement values; and performing a positional displacement correction for each of the scanning beams of the plurality of scanning beams based on the measurement values, the measuring includes measuring, in advance, displacement amounts of scanning positions of each of the scanning beams of the plurality of scanning beams in the sub-scanning direction, the displacement amounts changing according to temperature rise to obtain trends in changes in the displacement amounts, and the performing includes starting a control by setting the scanning positions within a pixel pitch based on the measured displacement amounts to counter the trends in changes in the displacement amounts of the scanning beams, wherein setting the scanning positions includes setting the positions of the scanning beams in the sub-scanning direction at time zero in directions opposite to anticipated displacement directions based on the trends in changes in the displacement amounts.