Patent ID: 9551954
Date: 2017-01-24
CPC Classifications: G03G

Claim:
1. An image forming apparatus comprising: an image forming unit; and a control unit configured to control the image forming unit; wherein the image forming unit comprises: a photosensitive member to be rotated; a light source including at least three light emitting elements each configured to emit a light beam to expose the photosensitive member, wherein the light beams emitted from the three light emitting elements expose positions on the photosensitive member different from each other in a rotational direction thereof; a deflection unit configured to deflect the light beams so that each deflected light beam scans the photosensitive member; and a signal generating unit configured to receive one of the light beams deflected by the deflection unit and to generate a reference signal as a reference for an emission timing of each of the light beams based on receipt of said one light beam, wherein the image forming unit develops, with toner, an electrostatic latent image formed on the photosensitive member scanned by the light beams, and forms an image on a recording medium by transferring a toner image from the photosensitive member onto the recording medium, wherein the control unit causes the light emitting elements to emit the light beams based on an image data, wherein the control unit controls the emission timing of each of the light emitting elements based on a delay amount set for each of the light emitting elements relative to a generation timing of the reference signal, wherein the control unit causes the image forming unit to form a first pattern image, a second pattern image, a third pattern image and a fourth pattern image by using all of the light emitting elements, wherein a position at which the first pattern and the second pattern are formed is different from a position at which the third pattern and the fourth pattern are formed with respect to a scanning direction of the light beams, and wherein the emission timing of the light beams emitted from the light emitting elements relative to the generation timing of the reference signal for forming the first pattern image and that for forming the second pattern image are different from each other, and the emission timing of the light beams emitted from the light emitting elements relative to the generation timing of the reference signal for forming the third pattern image and that for forming the fourth pattern image are different from each other.