Patent ID: 7184070

Claim:
An image forming apparatus comprising: an image carrier moved in a sub-scanning direction; an exposure device which scans, with an exposure light, the image carrier along a main scanning direction to form a latent image on the image carrier; a developing unit which supplies a toner to the latent image to effect development; a transfer unit which transfers a toner image to a sheet, and a fixing device which fixes the transferred toner image to the sheet, wherein the exposure device comprises: a housing; a light emitting section which emits a laser beam; a polygon mirror provided in the vicinity of a side in the housing, which includes a plurality of reflection planes along the main scanning direction to deflect the laser beam in the main scanning direction; a mirror provided in the vicinity of another side in the housing, which reflects the laser beam deflected by the polygon mirror at a predetermined angle to guide the laser beam outside the housing; and a projection provided on an outer surface of the housing between the polygon mirror and the mirror, wherein a central axis of the projection passes through an exposure light spot of the laser beam irradiated on the image carrier.