Ricoh Company, Ltd.

Takamichi Ohhashi

Eiichi Hayashi

Go Takahashi

Kan Aoki

Yasuo Yamanaka

Akio Hirano

Shinya Kamiura

Masafumi Furusawa

A molded plastic part prepared by injecting a resin in a cavity of a die so that a pressure is generated in the resin in the cavity and at least one transfer wall surface of the cavity is transferred to the resin. The plastic part has at least one transferred surface; at least one imperfectly transferred concave portion on a first surface thereof other than the transferred surface; and at least one imperfectly transferred convex portion on the first surface or a second surface thereof other than the transferred surface. The ratio (a)/(b) of the thickness (a) of the plastic part in a direction perpendicular to the transferred surface to the thickness (b) of the plastic part in a direction parallel to the transferred surface is less than 1.

Molded plastic part, method for molding plastic part, and optical scanning device using the molded plastic part

A plastic article is formable by using a metal die having a cavity to accommodate melted resin therein at a given pressure. The plastic article includes a transfer face to which is transferred a face shape of the metal die, a projection disposed at least one face other than the transfer face, an incomplete transfer face having a concave shape disposed at the same face on which the projection is disposed, formed by an incomplete transfer of a face shape of the cavity of the metal die, and an incomplete transfer face having a convex shape disposed at least one face other than the transfer face.

Plastic article, method of shaping plastic article, and optical scanning device having plastic article

A plastic optical element for use in an optical scanning device including light effective portions that focus light, and at least one link portion that connects the light effective portions in the sub-scanning direction, the link portion forming a border arc having a curvature radius R of 2 mm or greater and contacting the light effective portions such that the tangent of the light effective portion at the connection point of the light effective portion and the border arc matches the tangent of the border arc at the connection point.

Plastic optical element, optical scanning device, and image forming apparatus

A first plastic lens and a second plastic lens constituting each imaging optical system are arranged on opposite sides of an optical deflector, so that main scanning directions of optical beams scanned by the single optical deflector become substantially parallel to each other, and the first plastic lens and the second plastic lens of at least one of the plurality of (four) imaging optical systems are formed such that secondary components at scanning positions on the (four) surfaces to be scanned are arranged in a same direction, and are molded by a same mold cavity.

Optical scanning apparatus, image forming apparatus, and scanning-line-change correcting method

A plastic optical element for guiding a scanned light beam in a main scanning direction and a sub-scanning direction, which is prepared by a molding method using a die. The element includes: a main body including at least two optically functional surfaces, which are transfer surfaces formed by contacted with transfer surfaces of the die and through which the light beam passes; and at least two ribs located on surfaces of the main body other than the optically functional surfaces and extending in parallel in the main scanning direction. A recessed portion is present on a surface of at least one of the ribs, and the recessed portion has a side transfer surface and a bottom surface, which is a non-transfer surface, and the distance between the optically functional surfaces is less than the length of the main body in the sub-scanning direction.

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Kanagawa, Japan

Takamichi Ohhashi