Ricoh Company, Ltd.

Kan Aoki

Eiichi Hayashi

Go Takahashi

Takamichi Ohhashi

Akio Hirano

Akihiro Iwamatsu

Yasuo Yamanaka

Takamichi Ohta

Masafumi Furusawa

A plastic optical element for focusing light to a target includes a first lens and a second lens. The first lens includes an incident surface, a projection surface opposite the incident surface, and a non-optical surface through which light does not pass and that includes a non-transfer portion. At least one light beam passes from the incident surface to the projection surface. The second lens includes an incident surface, a projection surface opposite the incident surface, and a non-optical surface through which light does not pass and that includes a non-transfer portion disposed opposite the non-optical surface of the first lens. At least one light beam passes from the incident surface to the projection surface. The non-transfer portions of the first lens and the second lens are portions on which no surface is transferred from a surface of a mold used to form the plastic optical element.

Plastic optical element, optical scanner including the plastic optical element, and image forming apparatus including same

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 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

An optical scanning device for guiding a light beam to a member to scan the member with the light beam, including a light source emitting the light beam; a light deflector deflecting the light beam; a focusing optical system including a plastic optical element molded using a die. The optical element has least two transfer surfaces formed by contacting with transfer surfaces of the die and including a light entrance surface and a light exit surface; and a third surface including a non-transfer surface formed without contacting a transfer surface of the die. The light beam passes through the optical element in such a manner that the optical axis center of the light beam extends in a direction parallel to the shorter side of the optical element while being shifted from the dimensional center of the optical element toward the third surface of the optical element.

Optical scanning device, optical scanning method, and image forming apparatus, using the optical scanning device

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.

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

A plastic optical element is provided, which includes an optical element body having a transfer surface which includes at least one laser beam incident portion of a concave shape, and a support portion connected with the optical element body, in which the support portion is disposed in a direction of a tangent line at an end of the transfer surface, and the optical element body and a part of the support portion are molded in the same nest structure.

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Yamato, Japan

Kan Aoki