Ricoh Company, Ltd.

Yasuo Yamanaka

Kiyotaka Sawada

Toshihiro Kanematsu

Jun Watanabe

Akira Fukushima

Motoyasu Murai

Hidenobu Kishi

Eiichi Hayashi

Toshiharu Hatakeyama

Tadakatsu Harada

Hidekazu Yaginuma

Go Takahashi

Takamichi Ohhashi

Hiromichi Atsuumi

Tomonori Kimura

Hiroyuki Endoh

Kohei Shimbo

Yutaka Kaneko

Keiji Ueda

Toshiyuki Iseki

Eiri Sagae

Kan Aoki

Yasunori Sugimoto

Kenji Tajima

Akio Hirano

Yoshiyuki Nishio

Dan Aoki

Masanobu Munekata

Yasuharu Satoh

Tokuo Matsushima

Kazuhiko Fukushima

Yasuyuki Matsushita

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 flame retardant resin composition including: a thermoplastic resin; and a flame retardant, wherein the flame retardant includes a phosphorylated lignin derivative, and wherein the phosphorylated lignin derivative is produced by adding phosphoric acid to a lignin derivative obtained by subjecting a naturally occurring lignin to a predetermined treatment.

Flame retardant resin composition and molded product

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 disclosed fire retardant resin composition includes a thermoplastic resin and a fire retardant. The fire retardant is formed of phosphorated polysaccharide that is formed by attaching thiophosphoric acid ester or phosphoric acid ester to a side chain of natural polysaccharide.

Fire retardant resin composition

Disclosed is a copolymer resin composition including a lactic acid copolymer, the lactic acid copolymer containing monomer units represented by the following chemical formulas [1], [2], and [3], wherein a content of a monomer unit represented by the chemical formula [3] is 50 mol % or more and 95 mol % or less, a weight-average molecular weight of the lactic acid copolymer is 20,000 or more and 1,000,000 or less, and a deflection temperature of the lactic acid copolymer under load is 65&#xb0; C. or higher and 100&#xb0; C. or lower at a bending stress of 1.80 MPa.

Copolymer resin composition, molded product, and method of manufacturing a copolymer resin composition

An optical element having an optical surface and at least three convex portions on a surface different from the optical surface, wherein, among the at least three convex portions, two convex portions a space between whose centers is a maximum and one convex portion a length of a perpendicular from whose center to a straight line connecting centers of the two convex portions is a maximum satisfy a relationship of tan(h/p)&#x2266;a first specification value, wherein h is a greater one of heights of the optical element at centers of the two convex portions with reference to a tangential plane of the optical element at a position of a foot of the perpendicular, and p is a length of the perpendicular.

Optical element, optical scanning device, and image forming apparatus

A method of molding an object with a mold having a transfer face includes the steps of filling, separating, re-melting, re-contacting, cooling, and removing. The filling step fills a thermoplastic material, having a temperature greater than a softening temperature of the thermoplastic material, into a cavity space in the mold having a temperature smaller than the softening temperature of the thermoplastic material. The thermoplastic material comes in contact with the transfer face and is cooled. The separating step separates the transfer face from the thermoplastic material to form a heat-insulating layer between the thermoplastic material and transfer face. The re-melting step re-melts the thermoplastic material with heat energy retained inside the thermoplastic material. The re-contacting step re-contacts the re-melted thermoplastic material to the transfer face. The cooling step cools the thermoplastic material to a temperature smaller than the softening temperature of the thermoplastic material. The removing step removes the cooled thermoplastic material from the mold.

Apparatus and method for molding object with enhanced transferability of transfer face and object made by the same

A scanning and imaging optical system that condenses beams of light deflected by an optical deflector toward a surface to be scanned to form a light spot for optical scanning on the surface includes plurality of scanning lenses. Among the scanning lenses, at least two of the scanning lenses are resin lenses that are formed by plastic molding, and where a position coordinate in a horizontal scanning direction or in a vertical scanning direction is X, refractive index distribution in a cross-section with respect to the position coordinate X is &#x394;n(X), the refractive index distribution in a cross-section in the horizontal scanning direction that includes an optical axis or in the vertical scanning direction of the resin lenses, signs of the refractive index distribution &#x394;n(X) at least in the vertical scanning direction are not identical for all of the resin lenses.

Scanning and imaging optical system, optical scanner, and image forming apparatus with lenses of different signs and refractive index distribution increasing toward rim

A mold assembly for producing a molded object from resin. The assembly includes a cavity configured to be filled with resin to form at least one surface of the molded object into a predetermined shape with at least one transfer surface of the cavity. A molding insertion member is arranged to form another surface of the molded object, and a holding insertion piece is configured to hold the molding insertion member. The holding insertion piece includes a communication path that places a surface of the molding insertion member at a side opposite to the cavity in fluid communication with the exterior of the mold assembly and guides air from the exterior of the mold assembly toward the surface of the molding insertion member.

Method and mold assembly for producing a molded object

A plastic molding having high accuracy includes at least one transfer surface and at least one imperfect transfer portion having a concave or convex shape. The mold assembly includes a cavity into which molten resin is injected, a slide cavity piece which is capable of being slid at a prescribed time so that a gap is formed between the resin and the slide cavity piece, and a vent hole for supplying a compressed gas in the cavity. A method of producing the plastic molding includes the steps of heating resin to provide a molten resin, injecting the molten resin into a cavity of a molding, applying a resin-pressure to the molten resin, cooling the resin, sliding the slide cavity piece, and opening the mold assembly.

Plastic molding and a method and a mold assembly for producing the same

A plastic optical element producing method produces a plastic optical element by an injection molding, and includes the step of cooling the optical element to a room temperature to cool an optical surface of the plastic optical element with priority over other surfaces of the plastic optical element in a state where a temperature of the plastic optical element is within a predetermined temperature range which is less than or equal to a glass transition temperature of the resin material.

Plastic optical element, plastic optical element producing method and plastic optical element producing apparatus

A method for manufacturing an optical element, such as a plastic lens or similar, by molding. The manufacturing method includes the steps of molding the plastic lens under a prescribed molding temperature higher than a glass transition level of the plastic material used to from the optical element. The manufacturing method also includes the step of gradually cooling the optical element by at least 5&#xb0; C. with a speed which decreases by approximately 3&#xb0; C. per minute. The optical element formed from a plastic material includes a substantially rectangular shape having a width, a height, and a thickness, wherein the width is greater than the height and the thickness is measured in an optical axis direction. The optical element also includes a refractive index distribution of approximately 2&#xd7;10at a central half section of the height. The optical element may be defined by the manufacturing method having the molding step and the gradual cooling step. The apparatus used to manufacture the optical element includes a molding device for molding the optical element under a prescribed molding temperature higher than a glass transition level of the plastic material forming the optical element and a device for gradually cooling the optical element.

Method and apparatus for manufacturing plastic optical element and plastic optical element

An injection mold that is capable of producing a final molded component that meets designed optical properties is designed and produced efficiently by measuring shape errors, which adversely affect the optical properties, of at least one of a surface shape of a cavity of a first molding part and a molded component produced by using the first molding part, by reducing at least one of wavelength components of the shape errors, by generating processing information that is used to produce a second molding part that is used to mold the final molded component.

INJECTION MOLD, A PRODUCTION METHOD THEREOF, A PRODUCTION SYSTEM THEREOF, A DESIGNING APPARATUS AND A DESIGNING COMPUTER PROGRAM THEREOF, AN INJECTION METHOD, A MOLDED COMPONENT, AND AN OPTICAL SYSTEM THEREWITH

A method of producing a molding by injection molding, wherein only a part of the molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.

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Tokyo, Japan

Yasuo Yamanaka