Patent ID: 8149258
Filing Date: 2012-04-03
Classification: G03G

Abstract:
1. An image forming apparatus having a light-emitting unit configured to emit a laser beam, a rotatable polygon mirror configured to deflect the laser beam emitted by the light-emitting unit, and an image bearing member bearing images formed thereon by the laser beam deflected with the rotatable polygon mirror, and configured to suppress density unevenness due to exposure amount changes in a sub-scanning direction, which are caused by changes in a main scanning line interval of the laser beam on the image bearing member when forming images on the image bearing member by deflecting the laser beam with the rotatable polygonal mirror, the image forming apparatus comprising: an exposure amount correcting unit configured to have a control target of exposure amount changes of a low-frequency component, in which exposure amount changes of a high-frequency component in the exposure amount changes in the sub-scanning direction are suppressed or removed, and to correct an exposure amount so as to suppress the exposure amount changes of the low-frequency component of the control target, a storage unit configured to store luminance information of the laser beam for suppressing exposure amount changes in the low-frequency component for each face of the rotatable polygonal mirror, wherein the exposure amount correcting unit corrects the exposure amount on the basis of the luminance information stored in the storage unit, wherein the amplitude of the high-frequency component in the exposure amount changes corrected by the exposure amount correcting unit is larger than that of the exposure amount changes of the low-frequency component in the exposure amount changes corrected by the exposure amount correcting unit.