Optical scanning apparatus and image forming apparatus

Abstract

An optical scanning apparatus capable of fixing an optical member using a plate spring without forming a die cut hole and thus having high dust-proof performance includes a mirror supporting portion supporting a reflection mirror, and a projecting portion configured to form a gap between the reflection mirror supported on the mirror supporting portion and itself, and to deform the plate spring with the reflection mirror, and the projecting portion is provided with a cut hole for engaging the plate spring.

What is claimed is: 
     
         1 . An optical scanning apparatus including a light source configured to emit a light beam, a rotating polygonal mirror configured to deflect the light beam emitted from the light source so that a photosensitive member is scanned with the light beam, an optical member configured to guide the light beam deflected by the rotating polygonal mirror to the photosensitive member, and a casing accommodating the optical member therein, the optical scanning apparatus comprising:
 a first supporting portion formed integrally with the casing inside the casing and configured to support one end of the optical member in a longitudinal direction of the optical member;   a second supporting portion formed integrally with the casing inside the casing and configured to support another end of the optical member in the longitudinal direction of the optical member;   a first projecting portion formed integrally with the casing and projecting toward the inside of the casing from the casing so that the first supporting portion and the first projecting portion are formed in the casing to be adjacent each other in a direction along a plane perpendicular to the longitudinal direction of the optical member;   a second projecting portion formed integrally with the casing and projecting toward the inside of the casing from the casing the second supporting portion and the second projecting portion are formed in the casing to be adjacent each other in the direction along the plane perpendicular to the longitudinal direction of the optical member;   a first plate spring including a pressing portion configured to press the optical member and a contact portion being in contact with the first projecting portion, the first plate spring being configured to be elastically deformed so that a relative position between the pressing portion of the first plate spring and the contact portion of the first plate spring changes, and to cause the pressing portion of the first plate spring to press the optical member toward the supporting portion by being fitted between the first supporting potion and the first projecting portion to be elastically deformed,   a second plate spring including a pressing portion configured to press the optical member and a contact portion being in contact with the second projecting portion, the second plate spring being configured to be elastically deformed so that a relative position between the pressing portion of the second plate spring and the contact portion of the second plate spring changes, and to cause the pressing portion of the second plate spring to press the optical member toward the supporting portion by being fitted between the second supporting potion and the second projecting portion to be elastically deformed,   wherein the first projecting portion is provided with a first through hole and the first plate spring is provided with an engaging portion configured to engage with an inner wall of the first through hole, and the elastically deformed plate spring does not separate from between the first supporting potion and the first projecting portion by the engaging portion of the first plate spring and the inner wall of the first through hole engaging;   wherein the second projecting portion is provided with a second through hole and the second plate spring is provided with an engaging portion configured to engage with an inner wall of the second through hole, and the elastically deformed plate spring does not separate from between the second supporting potion and the second projecting portion by the engaging portion and the inner wall of the second through hole engaging.