| 摘要 |
<p>An optical scanner having good optical performance for directing a light beam from one curved surface mirror directly to a photosensitive drum without requiring any turn back mirror. The optical scanner comprises a light source section (1), an optical deflector (5) for scanning a light beam from the light source section, a first image-forming optical system (2, 3) interposed between the light source section and the optical deflector and forming a linear image on the deflecting surface of the optical deflector, and a second image-forming optical system (7) comprising a curved surface mirror and interposed between the optical deflector and a surface (8) to be scanned. The light beam from the first image-forming optical system impinges obliquely on a plane parallel with the horizontal scanning direction and including the normal to the deflecting surface of the optical deflector, and the light beam from the optical deflector impinges on a plane (hereinafter referred to YZ plane) parallel with the horizontal scanning direction and including the normal at the vertex of the curved surface mirror. The angle υM between the central axis of the light beam directed to the curved surface mirror and the YZ surface satisfies following relation. 10 < υM < 35.</p> |
