Patent ID: 7508565

Claim:
An optical beam scanning comprising: a light source for emitting one or plural luminous fluxes, a pre-deflection optical system to form a luminous flux emitted from the light source to image the luminous flux as a line image in a prescribed direction corresponding to a main scanning direction, a scanning unit configured to scan the image luminous flux by the pre-deflection optical system against a scanning subject, and a post-deflection optical system to image the luminous flux scanned by the scanning unit on the scanning subject, in which a width of the luminous flux made incident on the scanning unit from the pre-deflection optical system is wider than a width of one reflecting surface forming the scanning unit and an angle formed by an optical axis of the luminous flux made incident on the scanning unit and an optical axis of the post-deflection optical system is satisfied with a prescribed condition, wherein the post-deflection optical system includes at least one optical element configured by allowing a resin to flow into a molding die through a gate opening provided in advance to the molding die and then molding the resin into a prescribed shape; and in the optical element, a side corresponding to a side of the gate opening through which the resin flows is provided to a light incidence side where the luminous flux enters into the scanning unit.