Patent ID: 9046691
Filing Date: 2015-06-02
Classification: G02B,G03G,H04N

Abstract:
1. A laser scanning optical device that scans optical beams in a principal scanning direction on scan surfaces of photoreceptors provided for their respective colors, the device comprising: a plurality of light sources configured to emit optical beams from a plurality of emission points; a deflection section configured to, upon incidence of optical beams from the light sources, deflect the incident optical beams by a polygon mirror; and a scanning optical system configured to cause the optical beams deflected by the deflection section to form images on the scan surfaces for the respective colors, wherein, among the optical beams emitted by the light sources, a predetermined pair of optical beams are incident on the polygon mirror at the same inclination angle, symmetrically with respect to a horizontal plane perpendicular to a central axis of the polygon mirror and passing through a center of the polygon mirror in a secondary direction, the scanning optical system includes: the light sources that emit the pair of optical beams are arranged such that their respective planes of polarization are symmetrical to each other with respect to the horizontal plane, the planes of polarization being planes each including the emission points and having angles other than 0° and 90° with respect to the horizontal plane, the first and second individual scanning lenses are arranged so as to be symmetrical to each other with respect to the horizontal plane, the common scanning lens has a symmetrical shape in the secondary direction with respect to a plane including its own optical axis and being parallel to the horizontal plane, and each of the individual scanning lenses has an asymmetrical shape in the secondary direction with respect to a plane including its own optical axis and being parallel to the horizontal plane.