Abstract: An optical deflection device having: a rotor unit including a rotary polygon mirror having a plurality of mirror surfaces on the side surface portion and a holding member holding the polygon mirror; an air dynamic pressure bearing including a rotary bearing member to support the rotor unit and a fixed bearing member rotatably supporting the rotary member; and a stator unit which supports the fixed bearing member, including a winding coil oppositely arranged to the magnet, wherein prior to an assembly process, the adhesive agent layer is formed between the outer peripheral surface of the rotary bearing member and the inner peripheral surface of the holding member, the holding member and the rotary bearing member are set at the following condition, (the inner diameter of the holding member before the assembling)?(the outer diameter of the rotary bearing member before the assembling).

Abstract: An optical deflection device having: a rotor unit including a rotary polygon mirror having a plurality of mirror surfaces on the side surface portion and a holding member holding the polygon mirror; an air dynamic pressure bearing including a rotary bearing member to support the rotor unit and a fixed bearing member rotatably supporting the rotary member; and a stator unit which supports the fixed bearing member, including a winding coil oppositely arranged to the magnet, wherein prior to an assembly process, the adhesive agent layer is formed between the outer peripheral surface of the rotary bearing member and the inner peripheral surface of the holding member, the holding member and the rotary bearing member are set at the following condition, (the inner diameter of the holding member before the assembling)≧(the outer diameter of the rotary bearing member before the assembling).

Abstract: A light-beam deflecting apparatus is provided in which a polygon mirror is pushed against a flange to hold it stationary. The light-beam deflecting apparatus includes a base member; a polygon mirror rotatable with respect to the base member; a flange contacting the polygon mirror to hold the polygon mirror; and a pushing member to push the polygon mirror against the flange. One or both of contacting surfaces of the polygon mirror and the flange is/are finished to a surface roughness of Ry, which fulfills a first formula of Ry>3 &mgr;m or a second formula of 3 &mgr;m≦Ry≦20 &mgr;m.

Abstract: The invention concerns light-beam deflecting apparatus in which a polygon mirror is pushed against a flange to hold it stationary. The light-beam deflecting apparatus includes a base member; a polygon mirror being rotatable in respect to the base member; a flange contacting the polygon mirror to hold the polygon mirror; and pushing member to push the polygon mirror against the flange. One or both of contacting surfaces of the polygon mirror and the flange is/are finished to a surface roughness of Ry, which fulfills a first formula of Ry≧3 &mgr;m or a second formula of 3 &mgr;m≦Ry≦20 &mgr;m.