Optical scanning apparatus and image forming apparatus including optical scanning apparatus

摘要

In an optical scanning apparatus, a light source includes a plurality of light emitting elements. A light beam output from the source is scanned and deflected by a polygon mirror so as to form an electrostatic latent image on a surface of a light sensitive member. A control unit controls the source so that the source outputs the light beam in a first period before a second period in which the light beam deflected by the mirror forms the image. During the first period for outputting the light beam from the source a period for scanning a non-image region of the member in a state in which the rotation speed of the mirror is being accelerated or decelerated is made longer than a period for scanning the non-image region of the member in a state in which the rotation speed of the mirror is controlled at a constant speed.

主权项

1. An optical scanning apparatus, comprising:
a light source including a plurality of light emitting elements and configured to output a light beam from the plurality of light emitting elements based on image data for forming an electrostatic latent image on a photosensitive member; a rotational polygon mirror configured to deflect the light beam so that the light beam moves on a surface of the photosensitive member; a detection unit configured to detect the light beam deflected by the rotational polygon mirror; a light source control unit configured to cause the plurality of light emitting elements to output the light beam in a first period other than a second period in which the photosensitive member is scanned with the light beam for performing auto power control for the plurality of light emitting elements; and a rotation control unit configured to control a rotation speed of the rotational polygon mirror based on a detection cycle of the light beam detected by the detection unit, the rotation control unit performing acceleration control for accelerating changing the rotation speed of the rotational polygon mirror from a first target speed to a second target speed that is faster than the first target speed or constant speed control for maintaining the rotation speed of the rotational polygon mirror at the first target speed or the second target speed, the plurality of light emitting elements emit the light beams based on the image data in a state in which the constant speed control is performed, wherein a number of the auto power control for the light emitting elements in one scanning cycle of the light beam while the rotation control unit is performing the acceleration control, is smaller than a number of the auto power control for the light emitting elements in one scanning cycle of the light beam while the rotation control unit is performing the constant speed control.