Patent ID: 9057975
Filing Date: 2015-06-16
Classification: G03G

Abstract:
1. An image forming apparatus for starting image formation on the basis of a print command, comprising: first and second light sources each for emitting light according to image data; a rotatable polygonal mirror including a plurality of reflecting facets, wherein said rotatable polygonal mirror deflects the light emitted from said first light source toward a first photosensitive member and deflects the light emitted from said second light source toward a second photosensitive member; a first signal output unit for outputting a first signal by receiving, in a predetermined position, the light emitted from said first light source and deflected by said rotatable polygonal mirror; and a second signal output unit for outputting a second signal at timing on the basis of the first signal and a correction value, wherein the correction value is set for each reflecting facet of said rotatable polygonal mirror, wherein said first light source emits the light according to the image data based on a time when the first signal is outputted and said second light source emits the light according to the image data based on a time when the second signal is outputted so that latent images are formed on the first and second photosensitive members, respectively, wherein said second signal output unit starts the output of the second signal after a lapse of a predetermined period from start of the output of the first signal by said first signal output unit after said image forming apparatus receives the print command, and wherein after said image forming apparatus receives the print command and before the output of the second signal is started, said first light source starts light emission according to the image data.