Patent ID: 8743168

Claim:
An optical scanning apparatus comprising: a rotating polygon mirror provided with a plurality of reflection surfaces and configured to reflect a light beam emitted from a light source by the plurality of reflection surfaces; an optical member configured to direct the light beam on a photosensitive member; a housing including a holding member on which the rotating polygon mirror and the optical member are mounted and a first cover attached to the holding member and configured to protect the rotating polygon mirror and the optical member from dust wherein an opening is formed in a state in which the first cover is attached to the holding member, wherein the holding member includes a board on which the rotating polygon mirror and the optical member are installed and an outer wall which is upright from the board and configured to surround a periphery of the rotating polygon mirror and the optical member and the first cover is attached to the outer wall; and a second cover attached to the housing and configured to close an opening formed on the holding member or the first cover, or an opening formed by the holding member and the first cover, wherein the second cover is detachable from the housing in a state in which the first cover is attached to the holding member, and at least a part of the plurality of reflection surfaces is exposed from the housing in a state in which the second cover is detached from the housing, wherein the opening is formed on the outer wall.