Patent ID: 6411321
Filing Date: 2002-06-25
Classification: H04N

Abstract:
A light beam scanning apparatus comprising:a plurality of light sources to generate light beams; a plurality of beam combining units, provided to said light sources, respectively, to optically combine the light beams; a single scanning unit to reflect the combined light beams toward a surface to be scanned, and to cause the light beams to be scanned over the surface in a main scanning direction; a light beam power sensor, over which the light beams reflected from said single scanning unit are to be scanned, to sense power of the light beams on the surface; and a light beam power controller to control said light sources on the basis of a result of sensing by said light beam power sensor, wherein: said light beam power sensor comprises a first light-receiving element, a second light-receiving element and a third light-receiving element, said second and third light-receiving elements respectively provided on both sides of said first light-receiving element, an integrator for integrating an output of said first light receiving element, and a converter for converting a result of integration by said integrator; and wherein said integrator is reset when a light beam has passed over said second light-receiving element, and at the same time starts integration; and wherein said converter converts the result of the integration when the light beam has passed over said third light-receiving element.