Patent ID: 7248391

Claim:
An optical scanning system, comprising: light source means; deflecting means for scanningly deflecting a light beam from said light source means; and an imaging optical system for imaging, upon a scan surface to be scanned, the light beam deflected by said deflecting means, wherein said imaging optical system consists of a single imaging optical element with a light exit surface having a convex shape with respect to a main-scan sectional plane, and wherein relations 0.5 ≦φm/φp≦ 0.9 0 <dp/kp≦ 0.09 are satisfied, where φp is a power of said imaging optical element at an optical axis with respect to a main-scan direction, φm is a power of said imaging optical element at an outermost abaxial portion with respect to the main-scan direction, dp is a thickness of said imaging optical element at the optical axis, and kp is a k-θ coefficient of said imaging optical element at the optical axis.