Patent ID: 9075338
Filing Date: 2015-07-07
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a photosensitive member; a light illumination unit which includes a light emitting element and a rotating polygonal mirror including a plurality of mirror surfaces as scanning surfaces and is configured to reflect light emitted from the light emitting element from the scanning surfaces such that the photosensitive member which is charged is illuminated; a development unit configured to form a toner image by attaching toner to a latent image formed on the photosensitive member illuminated by the light illumination unit; and a control unit configured to cause the light illumination unit to perform normal exposure of a first exposure amount such that the toner is attached to an imaging portion to which the toner is to be attached on the photosensitive member and cause the light illumination unit to perform weak exposure of a second exposure amount smaller than the first exposure amount such that the toner is not attached to a non-image portion to which the toner is not to be attached on the photosensitive member, wherein the light illumination unit performs the normal exposure by causing the light emitting element to emit light according to a pulse corresponding to image data and performs the weak exposure by causing the light emitting element to emit light according to a pulse with a narrower width than the pulse corresponding to the image data, wherein the control unit is capable of executing a first mode for forming a toner image on the photosensitive member that rotates at a first speed and a second mode for forming a toner image on the photosensitive member that rotates at a second speed slower than the first speed, and wherein, in the first mode, the control unit causes the light illumination unit to perform a weak exposure by serially using adjacent scanning surfaces of the rotating polygonal mirror, and wherein, in the second mode, the control unit causes the light illumination unit to perform a weak exposure during one rotation of the rotating polygonal mirror by only using a part of the plurality of scanning surfaces of the rotating polygonal mirror.