Ricoh Company, Ltd.

Tohoku Ricoh Co., Ltd.

Takao Abe

Yoshihiro Takahashi

Yukio Itami

Mitsuo Suzuki

Yoshio Hashimoto

Koji Tsukahara

Hidetoshi Kojima

Tomotaka Takamura

Noriyuki Kadowaki

Kunio Ikeda

Makoto Endo

Takeshi Kikuchi

Kazuhiro Koseki

Masao Hatayama

Kiyoshi Shibuya

Yuzuru Kudo

An optical deflector, a method of producing the optical deflector, an optical scanning device, and an image forming apparatus are disclosed that are able to save resources, provide high reliability at low cost, and enable stacked and relatively-offset polygon mirrors to be arranged precisely. The optical deflector includes a rotary member supported by a bearing with plural polygon mirrors fixed thereon. The polygon mirrors are stacked along a rotation axis of the rotary member, the polygon mirrors are relatively offset by a predetermined angle in a rotation plane of the rotary member, and an effective deflection area of each of the reflection surfaces of any one of the polygon mirrors is positioned away from a center of the corresponding reflection surfaces of the other one of the polygon mirrors in the direction of the rotation axis.

Optical deflector, production method thereof, optical scanning device, and image forming apparatus

A dynamic pressure pneumatic bearing device has a groove for generating a dynamic pressure and formed on an inner circumferential face of a rotating shaft or an outer circumferential face of a fixed shaft; each of these shafts being formed by an aluminum alloy; and a wear resisting film formed on each of the inner circumferential face and the outer circumferential face. Another dynamic pressure pneumatic bearing device is constructed by a rotating shaft having a cylindrical hollow and a fixed shaft inserted into this hollow. The fixed shaft has a bearing face opposed to an inner circumferential face of the rotating shaft and separated from this inner circumferential face with a predetermined clearance. Herringbone grooves for generating a dynamic pressure and recessed portions having the same depth as the herringbone grooves are formed on the bearing face.

Dynamic pressure pneumatic bearing device and manufacturing method

A polygon scanner has a lighter rotating shaft on which a polygon mirror is mounted, to prevent a positional deviation of the polygon mirror from the rotating shaft in high speed rotation, in which the rotating shaft is supported through a dynamic pressure air bearing on a fixed shaft, in which the polygon mirror and motor constituent members are mounted on the rotating shaft, and in which the rotating shaft and the polygon mirror are made of respective light weight materials matched with each other in coefficient of thermal expansion, for example of aluminum or an aluminum alloy. Further, an anodic oxide film is formed at least on a portion where the rotating shaft could contact with the fixed shaft, and floating means is provided for constantly floating the rotating shaft relative to the fixed shaft upward in an axial direction thereof. A process for producing the polygon scanner comprises making a predetermined masking on a portion where the rotating shaft could contact with the fixed shaft, prior to an anodic oxidation treatment to form an anodic oxide film on the portion, and then performing the anodic oxidation treatment, whereby, during the treatment, forming an anodic oxide film and a pattern of recesses and protrusions for dynamic pressure generation corresponding to a pattern of the masking, which are constituent elements of a dynamic pressure air bearing.

Polygon scanner and production process thereof

Growing community of inventors

Shibata-machi, Japan

Takao Abe