| 摘要 |
PROBLEM TO BE SOLVED: To correct a light quantity distribution with respect to a scanning position nearly uniformly by making nearly uniform the light intensity of luminous flux with which a scanned surface is optically scanned. SOLUTION: In consideration of luminous flux width variation of deflected luminous flux 15 and the Gaussian intensity distribution 16 of incident luminous flux 12, the light quantity ratio of the deflected luminous flux 15 reflected and deflected by a faucet of a polygon mirror 5 is made uniform. In concrete, angle characteristics of the reflectivity of the faucet 6 are so set that (0.95×(Ia/ Ib)×Ra<=Rb<=1.05×(Ia/Ib)×Ra) holds, where Ia is the quantity of light when the luminous flux making an optical scan to the center part of an scanned effective area of the scanned surface 9 is made incident on the faucet 6, Ra the reflectivity of the faucet at the surface incidence angle, Ib the quantity of light when the luminous flux making an optical scan to the peripheral part of the scanned effective area of the scanned surface 9 is made incident on the faucet 6, and Rb the reflectivity of the faucet at the surface incidence angle. |
