Patent ID: 6519070
Filing Date: 2003-02-11
Classification: G02B,H04N

Abstract:
An optical scanning apparatus comprising:an incident optical system for causing a light beam emitted from light source means to be obliquely incident in a sub-scanning cross-section on a deflecting surface of an optical deflector having a plurality of deflecting surfaces; and an imaging optical system for forming, on a scanned surface, an image of the light beam deflected by the deflecting surface of the optical deflector, wherein letting K (dpi) be a recording density in a main scanning direction on the scanned surface, &ggr; be an absolute value of a maximum difference in a tilt angle between the deflecting surfaces in the sub-scanning cross-section, &agr; be an incident angle of the light beam incident on the deflecting surface in the sub-scanning cross-section, &thgr; be a scanning angle of an outermost off-axis light beam with respect to an optical axis of said imaging optical system in a main scanning cross-section, f be a focal length of said imaging optical system, and &phgr; be an angle a scanning central axis makes with an optical axis when an optical axis of said incident optical system opposing the deflecting surface is projected to the main scanning cross-section, a condition given by &LeftBracketingBar;sin&it;Î¸2Ã—sin&it;â€ƒ&it;Î³&it;â€ƒ&it;(cos&it;â€ƒ&it;Î±Ã—sin&it;â€ƒ&it;Î³Ã—cos&it;â€ƒ&it;Ï†Ã—cos&it;â€ƒ&it;Î¸2+cos&it;â€ƒ&it;Î±Ã—sin&it;â€ƒ&it;Î³Ã—sin&it;â€ƒ&it;Ï†Ã—sin&it;Î¸2+sin&it;â€ƒ&it;Î±Ã—cos&it;â€ƒ&it;Î³)&RightBracketingBar;<6.35fÃ—Kis satisfied.