Ricoh Printing Systems, Ltd.

Hitachi Koki Co., Ltd.

Satoru Wada

Takeshi Mochizuki

Susumu Saito

Junshin Sakamoto

Makoto Kurosawa

Kenichi Kugai

Kazutaka Setoma

Takahiro Kikuchi

An optical scanning apparatus includes a deflecting member that deflects and scans a light beam emitted from a light source, an optical element that scans and images the light beam on a medium to be scanned; and an opening member being disposed in a vicinity of the medium to be scanned. The opening member restricts both a scanning direction of the scanned and imaged light beam and a direction perpendicular to the scanning direction of the light beam.

Optical scanning apparatus and image forming apparatus

The invention aims at provision of an optical scanner in which an optics required for equalizing an optical magnification in a scanning range is produced with high accuracy, so that intervals among a plurality of scanning lines on a to-be-scanned surface are even in the scanning range. The scanning optics includes a refraction surface and a reflection surface whose sub-scanning-direction curvature radii vary continuously. The reflection surface is disposed on the to-be-scanned surface side of the refraction surface. The curvature radius of the reflection surface varies symmetrically with respect to the optical axis, and the curvature radius of the refraction surface varies asymmetrically with respect to the optical axis.

Optical scanner and image forming apparatus using the same

A rotary polygon mirror device comprises: a rotor including a polygon mirror secured to one end face of a cylinder, a central rod secured inside said cylinder in such a manner that the central rod is extended along the axis of the cylinder, and a thrust bearing magnet secured to the end face of the central rod, said magnet; and a casing coaxially surrounding the cylinder with a gap therebetween. In the device, the gap provides radial bearing means, and the cylinder and the casing are made equal in thermal expansion coefficient.

Dynamic pressure bearing and rotary polygon mirror device with the

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Ibaraki, Japan

Satoru Wada