| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical scanning device with high performance and excellent environmental temperature characteristic, and an image forming apparatus using the same. Ž<P>SOLUTION: The device comprises a first optical system for guiding a luminous flux emitted from a light source means to a deflecting means; and a second optical system for imaging the luminous flux deflected and scanned by the deflecting means onto a scanning object surface. The second optical system includes a glass imaging optical element having a positive power in a main scanning direction and a sub-scanning direction, and a plastic imaging optical element. The curvature radius within a sub-scanning cross section of at least one surface of the plastic imaging optical element is continuously changed over the main scanning direction of the imaging optical element, and conditions of ¾ϕ<SB>MP</SB>¾<0.25ϕ<SB>M</SB>and ¾ϕ<SB>SP</SB>¾<0.15ϕ<SB>S</SB>are satisfied, wherein ϕ<SB>M</SB>and ϕ<SB>S</SB>are powers within main-scanning and sub-scanning cross sections of the second optical system respectively, and ¾ϕ<SB>MP</SB>¾ and ¾ϕ<SB>SP</SB>¾ are absolute values of power within main scanning and sub-scanning cross sections of the plastic imaging optical element. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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