Patent ID: 7515170

Claim:
An optical scanner, comprising: a light source unit configured to emit light; an optical system configured to cause the light emitted from the light source unit to scan an object so as to form an image on the object; and a control unit configured to control the light source unit; wherein the light source unit includes a plurality of light emitting units arranged in a sub scanning direction, the control unit controls the light source unit to emit light at different positions on the object by using either n (n: positive integer) light emitting units or n+1 light emitting units selected from among the plurality of light emitting units, according to a positional shift amount of the image in the sub scanning direction, the control unit further controls pulse widths of driving signals used for driving each of the selected light emitting units, and a total light quantity of light emitted from the selected light emitting units is maintained at a fixed level.