OPTICAL SCANNING APPARATUS AND IMAGE FORMING APPARATUS

摘要

The optical scanning apparatus correctly measures a gap between the laser beams of a plurality of the laser beams even when the scanning speed is changed and when the variation is caused, rightly corrects the variation. Thus, the optical scanning apparatus inputs detection signal BD_IN to the edge detecting unit at timing at which the laser beam is detected. During the enable gating, the count value representing the distance between the head laser beam and the end laser beam is counted in the counting unit. A plurality of speed ratio parameters according to the degree of changes in the scanning speed is input in the selector. The selector selects any one of the speed ratio parameters and multiplies by the count value by the multiplier, it is controlled to obtain the same multiplication result whichever scanning speed may be selected.

主权项

1. An optical scanning apparatus comprising:
a light source having a plurality of light emitting elements, each of which emits laser beams, arranged such that the light emitting elements expose respective different positions in a scanning direction; a scanning mechanism configured to scan the laser beam emitted from each of the light emitting elements in the scanning direction; a sensor configured to output, by receiving the laser beams emitted from at least two light emitting elements, detection signals respectively corresponding to the at least two laser beams according to timing at which the at least two laser beams are respectively received; a measuring unit configured to obtain speed information representing scanning speed of the plurality of the laser beams and a gap between the detection signals corresponding to the at least two laser beams output from the sensor and measure a gap between particular laser beams in the scanning direction based on the gap between the detection signals and the speed information obtained; and a control unit configured to compare the gap measured and the gap in a reference state which is previously stored and control light emitting timing of the plurality of the light emitting elements according to a comparison result.