Patent ID: 7227676
Filing Date: 2007-06-05
Classification: G02B

Abstract:
1. An optical scanning apparatus, comprising: a first laser scanning unit having a first rotary polyhedral mirror which deflects and scans a first laser beam exposing a first image bearing member and a second laser beam exposing a second image bearing member; a second laser scanning unit having a second rotary polyhedral mirror which deflects and scans a third laser beam exposing a third image bearing member and a fourth laser beam exposing a fourth image bearing member; and control means which controls the rotational phase of the first rotary polyhedral mirror based on a laser beam irradiated to an image bearing member of which brightness is lower than the brightness of the toner that is developed on the first image bearing member and the brightness of the toner that is developed on the second image bearing member; and controls the rotational phase of the second rotary polyhedral mirror based on a laser beam irradiated to an image bearing member of which brightness is lower than the brightness of the toner that is developed on the third image bearing member and the brightness of the toner that is developed on the fourth image bearing member on the basis of said rotational phase which is controlled.