Patents by Inventor Tsutomu Nakagawa
Tsutomu Nakagawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9741839Abstract: A thyristor device that can include a disc-shaped device comprising a semiconductor material forming alternating p-n-p-n type layers. The device can include a gate area extending from an external gate lead contact point to a plurality of thyristor units connected in parallel. Each thyristor unit can include at least one exposed pB layer portion to form at least one plural point to which gate current can be directed. Further, an insulator layer can be formed over the gate area to insulate at least a portion of the gate electrode from the pB layer so that displacement current can be directed to short dots and then to the plural points. Current entering each thyristor unit can generate a turned-on area at each thyristor unit that spreads throughout the thyristor device.Type: GrantFiled: June 21, 2016Date of Patent: August 22, 2017Assignee: Powerex, Inc.Inventor: Tsutomu Nakagawa
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Patent number: 9303690Abstract: A rolling bearing comprises rollers and a retainer which holds the rollers. On an inner diameter surface of each of annular regions in the retainer, a cutout is formed from an axially outer side end surface of the retainer toward an inner side of the retainer. Each cutout has an outer diametrical position on a more radially outer position than an outer diametrical end of an inner-side projection of the retainer.Type: GrantFiled: November 22, 2012Date of Patent: April 5, 2016Assignee: NTN CORPORATIONInventors: Tsutomu Nakagawa, Masashi Nishimura, Shinji Oishi
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Patent number: 9273725Abstract: A rolling contact bearing assembly includes a cage including two or more arcuate members each having a plurality of pockets defined therein for accommodating a corresponding number of rollers arranged consecutively in a circumferential direction to form a ring shaped assembly. The arcuate members are connected together by a retention ring, having an elasticity, over a circumference of the cage. The arcuate members are displaced radially outwardly against an elastic compressive force of the retention ring such that circumferential gaps are formed at joints between the neighboring arcuate members. The arcuate members are held in a condition movable in the circumferential direction by a distance equal to the size of the circumferential gaps.Type: GrantFiled: October 14, 2010Date of Patent: March 1, 2016Assignee: NTN CORPORATIONInventors: Rino Fukami, Shinji Oishi, Makoto Nishikawa, Tsutomu Nakagawa
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Publication number: 20150049976Abstract: An object of the present invention is to prevent abrasion powder from accumulating and stacking in pockets in a retainer of a roller bearing, thereby protecting the rollers from brinelling and loss of lubrication for extended life of the roller bearing. On an inner diameter surface of annular regions in the retainer, cutouts are formed from the retainer's axially outer side end surface toward an inner side. The cutout has an outer diametrical position on a more radially outer position than an outer diametrical end of the inner-side projection of the retainer. This improves an axial flow of lubricant oil from an inner diameter side of the retainer toward the cutout which is formed in the annular region, making it less likely that dust such as metal abrasion powder contained in the lubricant oil will stay at the inner-side projection of the pillar.Type: ApplicationFiled: November 22, 2012Publication date: February 19, 2015Applicant: NTN CORPORATIONInventors: Tsutomu Nakagawa, Masashi Nishimura, Shinji Oishi
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Patent number: 8939865Abstract: Surface indentation and oil film shortage on rollers is prevented and longer service life of a roller bearing is achieved, by preventing wear debris from being caught and accumulated in pockets of a holder of the roller bearing. Positions and dimensional relations of the diameters of inner and outer ring raceways, the inner and outer diameters of the holder, and inner and outer protrusions which are provided to pillar parts of the holder to prevent the rollers from coming off are defined such that the inner and outer protrusions of the pillar parts always do not come into contact with the outer circumferential surfaces of the rollers in the state where the rollers and the holder are incorporated between inner and outer members. As a result, lubricant oil is smoothly circulated in gaps formed between the outer circumferential surfaces of the rollers and the pillar parts of the holder.Type: GrantFiled: August 30, 2012Date of Patent: January 27, 2015Assignee: NTN CorporationInventors: Tsutomu Nakagawa, Masashi Nishimura, Shinji Oishi
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Publication number: 20140221150Abstract: Surface indentation and oil film shortage on rollers is prevented and longer service life of a roller bearing is achieved, by preventing wear debris from being caught and accumulated in pockets of a holder of the roller bearing. Positions and dimensional relations of the diameters of inner and outer ring raceways, the inner and outer diameters of the holder, and inner and outer protrusions which are provided to pillar parts of the holder to prevent the rollers from coming off are defined such that the inner and outer protrusions of the pillar parts always do not come into contact with the outer circumferential surfaces of the rollers in the state where the rollers and the holder are incorporated between inner and outer members. As a result, lubricant oil is smoothly circulated in gaps formed between the outer circumferential surfaces of the rollers and the pillar parts of the holder.Type: ApplicationFiled: August 30, 2012Publication date: August 7, 2014Inventors: Tsutomu Nakagawa, Masashi Nishimura, Shinji Oishi
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Publication number: 20130148919Abstract: The present invention provides a rolling bearing which is excellent in strength, rigidity, heat resistance, and dimensional accuracy while being able to hold rolling elements in a stable manner and reduce manufacturing cost without degrading performance as a bearing and a manufacturing method for the rolling bearing. To achieve the object, the present invention adopts a rolling bearing including a cage provided with a plurality of pockets for housing and hold the rolling elements arranged at specific intervals in a circumferential direction in a peripheral wall of a cylindrical member. The cage is formed integrally by metal powder injection molding; and the cage includes a housing space for the rolling elements and a rolling-element fall-out prevention structure is formed by applying compressive working to an outer edge of the housing space in a direction from an outer circumferential surface toward a radial center of the cage.Type: ApplicationFiled: May 19, 2011Publication date: June 13, 2013Applicant: NTN CORPORATIONInventors: Akira Matsuo, Shunsuke Takeguchi, Shinji Oishi, Masashi Nishimura, Tsutomu Nakagawa
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Publication number: 20120207422Abstract: Two or more arcuate members (2A, 2B), each having a plurality of pockets (3) defined therein for accommodating corresponding rollers, are placed one above the other to form a ring shaped assembly and are subsequently connected non-separably together by means of a retention ring (4) to thereby complete the cage (1). The arcuate members (2A, 2B) are so connected together that its inner periphery may assume a position radially inwardly of the outer diameter of a shaft such that in a condition having been assembled onto the shaft, they can displace in a direction radially outwardly against an elastic compressive force of the retention ring (4) to invite a circumferential gap (S) at each joint between the arcuate members (2A, 2B).Type: ApplicationFiled: October 14, 2010Publication date: August 16, 2012Applicant: NTN CorporationInventors: Rino Fukami, Shinji Oishi, Makoto Nishikawa, Tsutomu Nakagawa
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Patent number: 8041269Abstract: A development apparatus includes a first developer chamber configured to store and supply the developer, a first developer bearer configured to convey the developer supplied from the first developer chamber to a first development domain, defined by a portion of the first developer bearer facing a latent image bearer, to develop the latent image, a second developer bearer configured to convey the developer passed through the first development domain to a second development domain, defined by a portion of the second developer bearer facing the latent image bearer, to develop the latent image, a second developer chamber configured to recover the developer passing through the second development domain and store the recovered developer, and a transfer prevention member provided between the second developer chamber and the second developer bearer to reduce a transfer of the developer from the second developer chamber to the second developer bearer.Type: GrantFiled: June 4, 2007Date of Patent: October 18, 2011Assignee: Ricoh Co., Ltd.Inventors: Tatsuya Kubo, Yoshitaka Fujinuma, Takashi Suzuki, Susumu Tateyama, Tsutomu Nakagawa, Masayoshi Nakayama
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Patent number: 7792466Abstract: In a developing device, a receive-convey screw conveys a developer received from a developer carrier. The receive-convey screw includes a receive-convey blade including a lower, outer circumferential end located in a downstream end of the receive-convey blade in the developer conveyance direction of the receive-convey screw. A slant-convey screw is disposed obliquely relative to an axial direction of the receive-convey screw, and conveys the developer received from the receive-convey screw upward. The slant-convey screw includes a slant-convey blade including a lower, outer circumferential end located in an upstream end of the slant-convey blade in the developer conveyance direction of the slant-convey screw, the lower, outer circumferential end being located at a height level lower than the lower, outer circumferential end of the receive-convey blade.Type: GrantFiled: May 29, 2007Date of Patent: September 7, 2010Assignee: Ricoh Company, Ltd.Inventors: Masayoshi Nakayama, Yoshitaka Fujinuma, Takashi Suzuki, Susumu Tateyama, Tsutomu Nakagawa, Tatsuya Kubo
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Patent number: 7792441Abstract: An image formation apparatus is disclosed. The image formation apparatus includes a transfer effectiveness detector that further includes a computing unit for converting a sensor output voltage into a toner adhesion amount, and a transfer effectiveness detecting unit for obtaining transfer effectiveness by comparing a toner adhesion amount Td on a photo conductor with a toner adhesion amount Tb on a middle transfer object. Here, the toner adhesion amount Td is obtained by the computing unit converting an output of a photo conductor image detection unit, and the toner adhesion amount Tb is obtained by the computing unit converting an output of a middle transfer object image detection unit. When the transfer effectiveness detection unit determines that an abnormality is present in the transfer, whether the abnormality is due to decreased development capacity or due to decreased transfer effectiveness can be determined.Type: GrantFiled: June 21, 2007Date of Patent: September 7, 2010Assignee: Ricoh Company, Ltd.Inventors: Shinichi Akatsu, Takashi Suzuki, Tsutomu Nakagawa, Shigeru Tosa
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Patent number: 7689153Abstract: An image formation system is configured by connecting two or more image formation devices. The system includes a fixing device fixing an unfixed development image to a record medium and a charge elimination device eliminating a charge of the record medium in an inlet of the fixing device of the second or later image formation device.Type: GrantFiled: May 20, 2005Date of Patent: March 30, 2010Assignee: Ricoh Company, Ltd.Inventors: Tsutomu Nakagawa, Koji Kato, Tomonari Hokkyo, Kenji Nozawa
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Patent number: 7683150Abstract: A water-absorbing resin has a polymer molecular chain in which 50 mol % or more of repeating units in the chain are carboxy group-containing units, wherein the carboxy group neutralization ratio in the central part of the resin is 60 mol % or more and the carboxy group neutralization ratio on the external surface of the resin is 50 mol % or less. A method for producing the water-absorbing resin comprises polymerizing a monomer solution to form a polymer, drying the resulting polymer, and heat-treating the dried polymer, wherein the monomer solution contains a mixture comprising an alkali metal salt of an unsaturated carboxylic acid and an ammonium salt thereof, the percentage of the ammonium salt being more than 50 mol % of the mixture, and further contains a condensation crosslinking agent.Type: GrantFiled: July 27, 2006Date of Patent: March 23, 2010Assignee: Asahi Kasei Chemicals CorporationInventors: Naonori Higashimoto, Tsutomu Nakagawa
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Patent number: 7580657Abstract: A developing device includes first-third sections, a developing roller, a partitioning wall and a toner concentration detector. The first-third sections have first-third screw augers respectively. The partitioning wall isolates the third section from the first section and the second section. A supply opening is formed in a portion of the partitioning wall opposing the first section. A toner concentration detector is disposed in the third section. The first screw auger conveys developer including toner to the developing roller, into the third section via the supply opening, and into the second section. The second screw auger conveys developer accommodated in the second section into the third section. The third screw auger conveys developer accommodated in the third section into the first section. Toner is replenished into the third section based on a detection result by the toner concentration detector.Type: GrantFiled: July 27, 2006Date of Patent: August 25, 2009Assignee: Ricoh Company, Ltd.Inventors: Susumu Tateyama, Yoshitaka Fujinuma, Tsutomu Nakagawa, Masayoshi Nakayama
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Patent number: 7538791Abstract: The white chromaticity, in which the illumination environment is considered, is measured for each individual color monitor (100). A reference body (Q), comprising a perfect diffuser, is applied on the screen of the color monitor (100). By a test pattern display means (210), a test pattern (T) is displayed on the screen of the color monitor (100) based on tone values of the three primary colors R, G, and B that are stored in a tone value storage means (220). While fixing the tone value of the primary color R at 255, the tone values of the primary colors G and B are varied cyclically from 0 to 255 in a prescribed period by a tone value varying means (240). An operator inputs the result of comparing the color of the test pattern (T) and the color of the reference body (Q). When a comparison result indicating the matching of the two is input, a comparison result entering means (230) outputs an agreement signal.Type: GrantFiled: June 11, 2004Date of Patent: May 26, 2009Assignee: Dai Nippon Printing Co., Ltd.Inventors: Tohru Sugiyama, Tsutomu Nakagawa
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Publication number: 20080027180Abstract: A water-absorbing resin has a polymer molecular chain in which 50 mol % or more of repeating units in the chain are carboxy group-containing units, wherein the carboxy group neutralization ratio in the central part of the resin is 60 mol % or more and the carboxy group neutralization ratio on the external surface of the resin is 50 mol % or less. A method for producing the water-absorbing resin comprises polymerizing a monomer solution to form a polymer, drying the resulting polymer, and heat-treating the dried polymer, wherein the monomer solution contains a mixture comprising an alkali metal salt of an unsaturated carboxylic acid and an ammonium salt thereof, the percentage of the ammonium salt being more than 50 mol % of the mixture, and further contains a condensation crosslinking agent.Type: ApplicationFiled: July 27, 2006Publication date: January 31, 2008Applicant: ASAHI KASEI CHEMICALS CORPORATIONInventors: Naonori Higashimoto, Tsutomu Nakagawa
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Patent number: 7324778Abstract: A fixing device wherein supposing that the total load given to a heating roller and a pressure roller is W (kgf) and the area of the pressure contact portion of the heating roller with respect to the pressure roller (nip area) is S (cm2), the nip pressure (=W/S) is 2.7 kgf/cm2 or more and the length of the pressure contact portion in the direction parallel to the direction of conveyance of a recording material is defined to be 14 mm or more.Type: GrantFiled: July 1, 2005Date of Patent: January 29, 2008Assignee: Ricoh Printing Systems, Ltd.Inventors: Takashi Suzuki, Teruaki Mitsuya, Keisuke Kubota, Masato Miwa, Yoshitaka Fujinuma, Tsutomu Nakagawa
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Publication number: 20080019718Abstract: An image formation apparatus is disclosed. The image formation apparatus includes a transfer effectiveness detector that further includes a computing unit for converting a sensor output voltage into a toner adhesion amount, and a transfer effectiveness detecting unit for obtaining transfer effectiveness by comparing a toner adhesion amount Td on a photo conductor with a toner adhesion amount Tb on a middle transfer object. Here, the toner adhesion amount Td is obtained by the computing unit converting an output of a photo conductor image detection unit, and the toner adhesion amount Tb is obtained by the computing unit converting an output of a middle transfer object image detection unit. When the transfer effectiveness detection unit determines that an abnormality is present in the transfer, whether the abnormality is due to decreased development capacity or due to decreased transfer effectiveness can be determined.Type: ApplicationFiled: June 21, 2007Publication date: January 24, 2008Inventors: Shinichi Akatsu, Takashi Suzuki, Tsutomu Nakagawa, Shigeru Tosa
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Publication number: 20070280744Abstract: A development apparatus includes a first developer chamber configured to store and supply the developer, a first developer bearer configured to convey the developer supplied from the first developer chamber to a first development domain, defined by a portion of the first developer bearer facing a latent image bearer, to develop the latent image, a second developer bearer configured to convey the developer passed through the first development domain to a second development domain, defined by a portion of the second developer bearer facing the latent image bearer, to develop the latent image, a second developer chamber configured to recover the developer passing through the second development domain and store the recovered developer, and a transfer prevention member provided between the second developer chamber and the second developer bearer to reduce a transfer of the developer from the second developer chamber to the second developer bearer.Type: ApplicationFiled: June 4, 2007Publication date: December 6, 2007Inventors: Tatsuya Kubo, Yoshitaka Fujinuma, Takashi Suzuki, Susumu Tateyama, Tsutomu Nakagawa, Masayoshi Nakayama
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Publication number: 20070274742Abstract: An image forming apparatus includes a latent image carrier and a developing device configured to develop a latent image carried by the latent image carrier. In the developing device, a receive-convey screw conveys a developer received from a developer carrier. The receive-convey screw includes a receive-convey blade including a lower, outer circumferential end located in a downstream end of the receive-convey blade in the developer conveyance direction of the receive-convey screw. A slant-convey screw is disposed obliquely relative to an axial direction of the receive-convey screw, and conveys the developer received from the receive-convey screw upward. The slant-convey screw includes a slant-convey blade including a lower, outer circumferential end located in an upstream end of the slant-convey blade in the developer conveyance direction of the slant-convey screw, the lower, outer circumferential end being located at a height level lower than the lower, outer circumferential end of the receive-convey blade.Type: ApplicationFiled: May 29, 2007Publication date: November 29, 2007Inventors: Masayoshi Nakayama, Yoshitaka Fujinuma, Takashi Suzuki, Susumu Tateyama, Tsutomu Nakagawa, Tatsuya Kubo