Patent ID: 7271823
Filing Date: 2007-09-18
Classification: G02B

Abstract:
1. An optical scanner comprising: a plurality of light sources, each of which produces a bundle of light beams; a deflector including a deflecting-reflecting surface which deflects a plurality of the bundles of light beams emitted from the plurality of light sources; a coupling lens which couples the bundles of light beams emitted from the plurality of light sources; a cylindrical lens which directs the bundles of light beams coupled by the coupling lens to the deflector, wherein each individual light beam of each of the bundles of light beams from a respective one of the plurality of light sources is incident on the deflecting-reflecting surface of the deflector with an angle of incidence, wherein the average of the angles of incidence of the individual light beams of each of the bundles of light beams is an average angle of incidence for the respective bundle of light beams, and wherein the average angles of incidence for the bundles of light beams from the plurality of light sources have values between a maximum and a minimum value; a parallel plate through which the bundles of light beams incident on and deflected from the deflector pass; and a scanning-imaging optical system which condenses the bundles of light beams deflected from the deflector on a surface to be scanned, wherein the bundles of light beams incident on the deflector have an angle between the bundles in a rotating plane of the deflector, and expressions are satisfied, where θ 1 max and θ 1 min are maximum and minimum values of an average angle of incidence on the deflecting-reflecting surface in the rotating plane of the deflector, θ 2 is a half-view angle corresponding to an effective writing width, and α is an angle of inclination of the parallel plate in the rotating plane of the deflector with respect to a main scanning direction.