Patent ID: 7956884
Filing Date: 2011-06-07
Classification: B41J,G02B

Abstract:
1. An optical scanning device that employs a multi-beam scanning method, the optical scanning device comprising: a surface emitting laser light source that includes a plurality of laser emission sources; a first optical system that converts a form of laser beams in a linearly polarized state that are emitted from the plurality of laser emission sources into a form appropriate for a subsequent optical system; a deflection unit that includes a deflection reflection surface and deflects the laser beams of which form is converted by the first optical system by reflecting the laser beams by the deflection reflection surface; a second optical system that focuses the laser beams of which form is converted by the first optical system as line images that are separated from one another in a sub-scanning direction and are long in a main-scanning direction near the deflection reflection surface; a third optical system that focuses the laser beams deflected by the deflection unit on a scanning surface as a plurality of light spots that are separated from one another in the sub-scanning direction; a parallel-plate-like quarter wavelength plate that is arranged between the surface emitting laser light source and the first optical system; and an aperture that performs beam-shaping on the laser light beams of which form is converted by the first optical system, wherein the quarter wavelength plate is arranged to be tilted with respect to a plane that is perpendicular to an optical axis of the first optical system; and the quarter wavelength plate is arranged to tilt in the sub-scanning direction with respect to the plane when Ay>Az is satisfied and in the main-scanning direction with respect to the plane when Ay<Az is satisfied, where Ay is an opening size of the aperture in the main-scanning direction and Az is an opening size of the aperture in the sub-scanning direction.