OPTICAL SCANNING DEVICE AND IMAGE FORMING APPARATUS USING THE SAME

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. 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 ¾ MP¾