Patent ID: 7016092
Filing Date: 2006-03-21
Classification: B41J,G02B

Abstract:
1. An optical scanning apparatus for scanning a plurality of surfaces to be scanned with light beams, comprising: a plurality of light source means; a first turn back mirror for reflecting a plurality of light beams emitted from the plurality of light source means; a light deflector for deflecting the plurality of light beams reflected by the first turn back mirror, using a same deflecting surface; and an imaging optical system for guiding the plurality of light beams deflected by the same deflecting surface of the light deflector onto different surfaces to be scanned, respectively, wherein the first turn back mirror is disposed within an effective scanning range in a main scanning section when the first turn back mirror is projected in the main scanning section, in a sub-scanning section, the plurality of light beams are reflected by the first turn back mirror in mutually different directions with respect to a normal line direction of a reflecting surface of the first turn back mirror, and made incident on the same deflecting surface of the light deflector at mutually different angles, and the following condition is satisfied, where d represents a largest interval on the first turn back mirror in the sub-scanning direction between two principal rays among principal rays of the plurality of light beams reflected in the mutually different directions with respect to a normal line direction of said reflecting surface of the first turn back mirror, a represents an angle in the sub-scanning direction formed by the principal ray of the light beam among the plurality of light beams incident on the same deflecting surface of the light deflector at the mutually different angles, having a smallest incident angle with respect to the normal line thereof, and the normal line of the deflecting surface, θ represents an incident angle in the sub-scanning direction determined by an F-number of the light beam having the smallest incident angle, and L represents a distance between the deflecting surface of the light deflector and the reflecting surface of the first turn back mirror.