Patent ID: 6999218

Claim:
A light scanning apparatus comprising: a light source that irradiates a light beam; a first optical system that shapes the light beam irradiated from the light source; a rotating polygonmirror that has a plurality of reflection faces that reflect, while the rotating polygon mirror is rotated, the light beam shaped by the first optical system, thereby deflection-scanning the light beam; a scanning optical system that focuses the light beam deflection-scanned by the rotating polygon mirror on a face being scanned to form an image; and an aperture that includes an H-shaped aperture portion having end portions formed to be enlarged in a sub-scanning direction compared with a central portion of the aperture portion, the aperture reduces a width in a main scanning direction of the light beam incident to the reflection face, the width of the light beam in the main scanning direction along a direction of the deflection-scanning having been widened larger than the width of the reflection face by the shaping of the first optical system, wherein the aperture reduces the width of the light beam in the main scanning direction in a region outside an effective scanning region.