| 摘要 |
PURPOSE: To obtain an image having high quality and always keeping unmagnification performance without being affected by the rotation irregularity of a polygonal mirror by correcting a writing clock frequency based on the average value of a measured count number. CONSTITUTION: This image forming device performing recording by means of plural laser beams is constituted of a first laser beam detecting sensor 105 whose length is perpendicular to a laser beam main scanning direction and which corresponds to a laser beam fluctuation allowable range caused by plane tilt, and a second laser beam detecting sensor 106 which is arranged on a downstream side in the laser beam main scanning direction, which corresponds to laser beam fluctuation detectable range caused by the plane tilt, and whose length is perpendicular to the laser main scanning direction. The measurement of count number equivalent to laser beam scanning time between two points are plurally performed, and the writing clock frequency is corrected based on the average value of the measured count number. Consequently, the influence of the rotation irregularity within one rotation of the polygonal mirror 102 is eliminated so as to correct the writing clock frequency and the image having high quality can be obtained. |
