Patent ID: 6954295

Claim:
A light scanning optical system comprising an incidence optical system for causing a beam emitted from light source means to be incident on a deflecting surface of a light deflector from an oblique direction in a sub-scanning cross-section, and an imaging optical system for imaging the beam reflected and deflected by said light deflector on a surface to be scanned, wherein when a maximum value and a minimum value of a peak intensity in an effective scanning area of a spot imaged on said surface to be scanned by said imaging optical system are defined as E MAX and E MIN , respectively, the following condition is satisfied: 0.8 ≤ E MIN E MAX , and wherein when a difference in an incidence point in a sub-scanning direction on said surface to be scanned between two marginal rays of the beam reflected and deflected by the deflecting surface of said light deflector in the main scanning direction is defined as Δs and a diameter of the spot imaged on said surface to be scanned which becomes 1/e 2 relative to the peak intensity in the sub-scanning direction is defined as Ds, the following condition is satisfied: Δ ⁢ ⁢ s Ds ≤ 0.9 .