Patent ID: 9618872
Date: 2017-04-11
CPC Classifications: G02B,G03G

Claim:
1. An optical scanning apparatus comprising: a light source configured to emit a light beam for exposing a photosensitive member; a rotary polygonal mirror configured to deflect the light beam emitted from the light source so as to scan the photosensitive member; an optical box configured to house the rotary polygonal mirror in an interior thereof and provided with a plurality of box engaging portions at a plurality of positions on an outer surface of a wall of the optical box; and a cover mounted on the optical box and provided with a plurality of first protrusions and a plurality of second protrusions along the outer surface, wherein each of the first protrusions is provided with a cover engaging portion configured to engage one of the plurality of box engaging portions and the plurality of cover engaging portions engages the plurality of the box engaging portions respectively to fix the cover to the optical box, wherein the plurality of second protrusions protrudes from corners of the cover when looked from a direction of rotating axis of the rotary polygonal mirror, wherein the plurality of the first protrusions and the plurality of the second protrusions are provided to the cover so that a distal end of at least one of the plurality of the second protrusions and a top portion of the wall pass each other prior to timing when distal ends of the first protrusions and the top portion of the wall of the optical box pass each other when mounting the cover on the optical box, and wherein the distal ends of the plurality of the second protrusions function as guide members for determining the direction of relative movement between the cover and the optical box while moving along the wall by either allowing or restricting movement between the cover and the optical box.