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Abstract

This invention provides an optical scanning apparatus in which the degree of sensitivity of the bending of a scanning line on a surface to be scanned resulting from the disposition error of a scanning optical system is reduced, whereby good images can always be obtained, and an image forming apparatus using the same. The optical scanning apparatus has deflecting means for deflecting a beam emitted from light source means, and a scanning optical system having a plurality of scanning lenses for directing the beam onto the surface to be scanned, and a first scanning lens La is such that the shape thereof in a main scanning cross section is a meniscus shape having positive refractive power, and satisfies the condition that d1/fm<0.06, where fm is the focal length of the scanning optical system in the main scanning cross section, and d1 is the central thickness of the first scanning lens, and a second scanning lens is such that. in the main scanning cross section, the shape of the light incidence side surface thereof is an aspherical free of an inflection point or arcuate shape, and satisfies the condition that 2.5<|R3/fm|, where R3 is the radius of curvature of the light incidence side surface on an optical axis in the main scanning cross section.

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First Claim