Patent ID: 7995088

Claim:
An optical scanning apparatus comprising: a light source adapted to emit a light beam; a light scanning unit adapted to deflect the light beam emitted from said light source to scan on an image carrier; an electro-optical crystal member which is provided in an optical path between said light source and said light scanning unit and deflects the light beam emitted from said light source by an applied voltage; at least a light amount detecting unit adapted to detect an amount of light beam deflected by said electro-optical crystal member; and a light amount control unit adapted to control the amount of laser beam emitted from said light source based on detection result obtained by said at least light amount detecting units; wherein said electro-optical crystal member is made of an electro-optical crystal having a characteristic that a refractive index of said electro-optical crystal changes upon an applied voltage, further comprising a voltage control unit adapted to control a voltage applied to the electro-optical crystal; a processing unit adapted to control turning on and off of said light source and a voltage applied to the electro-optical crystal by said voltage control unit, wherein said processing unit, along with scanning of a laser beam in a main scanning direction, upon BD detection after turning on said light source, turns off said light source and causes said voltage control unit to apply a predetermined voltage to the electro-optical crystal, causes said light amount control unit to start light amount control by making said light source turn on, upon completion of the light amount control, turns off said light source and causes said voltage control unit to stop applying the predetermined voltage to the electro-optical crystal, and causes said light scanning unit to scan the light beam on an image carrier by turning on said light source to emit light.