Patent ID: 8115793
Filing Date: 2012-02-14
Classification: B41J,G02B,H04N

Abstract:
1. An optical scanning device, comprising: at least one scanning unit including deflecting means configured to scanningly deflect a light beam emitted from light source means, and an imaging optical system configured to image the light beam scanningly deflected by a deflecting surface of said deflecting means upon a plurality of photosensitive drums, wherein, in each of a plurality of light paths extending from said deflecting means to the plurality of photosensitive drums, at least one reflection member is provided to turn the light path in a sub-scan direction at a turn angle, wherein the plurality of light paths are different in the number of the reflection members, wherein a polarization direction of a light beam incident on a reflection surface of each reflection member disposed at each of the plurality of light paths is S-polarized at an optical axis of said imaging optical system, wherein the reflection surfaces of all the reflection members disposed at the plurality of light paths have the same film structure, wherein a difference between totals of the turn angles in any two of the optical paths at the optical axis of said imaging optical system is not greater than 40 degrees, and wherein, when the incidence angle of the light beam on the reflection member in the sub-scan direction at the optical axis of said imaging optical system is β, the incidence angle of the light beam on the reflection member in the sub-scan direction outside the optical axis of said imaging optical system is δ, a reflectance as an S-polarized light is incident on the reflection member at an incidence angle δ is Rs(δ), and a reflectance as a P-polarized light is incident on the reflection member at an incidence angle δ is Rp(δ), and when δ≧50 degrees, a condition where is satisfied.