Patents by Inventor Tokuya Ohjimi
Tokuya Ohjimi 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: 8849142Abstract: Disclosed is an image forming device including a fixing unit that fixes a first image to be fixed onto a sheet, the first image to be fixed being supported on the sheet, a target fixing temperature varying unit that varies a target fixing temperature during a time period in which a fixing process is performed, and a gradation processing unit that applies a gradation process to first image information. The target fixing temperature varying unit varies the target fixing temperature for the sheet of the recording medium to which the fixing process is applied, depending on presence or absence of a halftone process, and depending on a type of the gradation process to be utilized.Type: GrantFiled: May 22, 2012Date of Patent: September 30, 2014Assignee: Ricoh Company, Ltd.Inventors: Hiroyuki Sugiyama, Jun Yura, Tokuya Ohjimi, Yukiko Iwasaki, Jun Shiori, Masaki Sukesako, Kazuaki Kamihara, Hironobu Takeshita, Ryota Kidera
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Patent number: 8649692Abstract: A toner replenishing device includes a toner container that stores toner, a toner replenishing device that supplies toner from the toner container to a developing device, and a toner condition detector that detects an aggregated condition of the toner stored in the toner container. A toner softening device is provided to soften toner stored in the toner container. A controller is also provided to drive the toner softening device for a prescribed time period in accordance with a detection result obtained by the toner condition detector.Type: GrantFiled: October 3, 2011Date of Patent: February 11, 2014Assignee: Ricoh Company, Ltd.Inventors: Masaki Sukesako, Tokuya Ohjimi
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Publication number: 20120315060Abstract: Disclosed is an image forming device including a fixing unit that fixes a first image to be fixed onto a sheet, the first image to be fixed being supported on the sheet, a target fixing temperature varying unit that varies a target fixing temperature during a time period in which a fixing process is performed, and a gradation processing unit that applies a gradation process to first image information. The target fixing temperature varying unit varies the target fixing temperature for the sheet of the recording medium to which the fixing process is applied, depending on presence or absence of a halftone process, and depending on a type of the gradation process to be utilized.Type: ApplicationFiled: May 22, 2012Publication date: December 13, 2012Applicant: RICOH COMPANY, LTD.Inventors: Hiroyuki Sugiyama, Jun Yura, Tokuya Ohjimi, Yukiko Iwasaki, Jun Shiori, Masaki Sukesako, Kazuaki Kamihara, Hironobu Takeshita, Ryota Kidera
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Publication number: 20120099878Abstract: A toner replenishing device comprises a toner container that stores toner, a toner replenishing device that supplies toner from the toner container to a developing device, and a toner condition detector that detects an aggregated condition of the toner stored in the toner container. A toner softening device is provided to soften toner stored in the toner container. A controller is also provided to drive the toner softening device for a prescribed time period in accordance with a detection result obtained by the toner condition detector.Type: ApplicationFiled: October 3, 2011Publication date: April 26, 2012Inventors: Masaki SUKESAKO, Tokuya Ohjimi
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Patent number: 7477856Abstract: An image forming apparatus including an image bearing member, a charging member, and a measuring member. The image forming member is configured to bear an image. The charging member is configured to charge a surface of the image bearing member when a direct current bias voltage is added to at least an alternating bias voltage which is applied to the charging member, and has a frequency fc of the alternating bias voltage. The measuring member is configured to measure a potential of the surface of the image bearing member, and has a drive frequency fvsen. The relationship of the frequency fc and the drive frequency fvsen is expressed as fc?fvsen×n and fc×n?fvsen.Type: GrantFiled: November 14, 2005Date of Patent: January 13, 2009Assignee: Ricoh Company, Ltd.Inventors: Takuzi Yoneda, Hiroshi Ono, Masanori Kawasumi, Yuji Arai, Toshio Koike, Ken Amemiya, Tokuya Ohjimi, Takatsugu Fujishiro, Masami Tomita, Haruji Mizuishi, Hitoshi Ishibashi
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Patent number: 7272354Abstract: A cleaning unit includes a first blade and a second blade. The first blade is in contact with an image carrier or a paper carrier and removes adhered substances remained on surface of these. The second blade has an abrasive layer that is formed by including abrasive particles in an elastic material and is disposed in the downstream side of the first blade. The second blade is allowed to be in contact with the image carrier 1 or the paper carrier. Volume occupancy of abrasive particles in an area of contact of the second blade with either the image carrier or the paper carrier is not less than 50 percent and not more than 90 percent.Type: GrantFiled: May 26, 2006Date of Patent: September 18, 2007Assignee: Ricoh Company, Ltd.Inventors: Eisaku Murakami, Masami Tomita, Masanori Kawasumi, Toshio Koike, Naohiro Kumagai, Atsushi Sampe, Takeshi Shintani, Masato Yanagida, Yutaka Takahashi, Hiroya Hirose, Shin Hasegawa, Hiroyuki Nagashima, Takeshi Uchitani, Kazunori Karasawa, Kentaroh Matsumoto, Tokuya Ohjimi, Mugijiroh Uno
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Patent number: 7266324Abstract: A charging device including: a charging roller having a metal cylinder and an elastic layer located on the metal cylinder; a cleaner configured to clean the charging roller, which includes an electroconductive brush roller including a roller having a shaft; and hair located overlying the roller, wherein the hair includes a fiber which has a width of from 0.1 to 20 denier, and a length of from 0.3 to 2.5 mm and which is planted at a density of from 7,000 to 46,000 lines/cm2, and a member configured to impart substantially the same potential as that of the charging roller to the electroconductive brush roller when a bias voltage is applied to the charging roller. A process cartridge and an image forming apparatus including the charging device are also provided.Type: GrantFiled: June 30, 2006Date of Patent: September 4, 2007Assignee: Ricoh Company LimitedInventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Tokuya Ohjimi, Masami Tomita, Takeshi Shintani
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Publication number: 20070014588Abstract: A charging device including: a charging roller having a metal cylinder and an elastic layer located on the metal cylinder; a cleaner configured to clean the charging roller, which includes an electroconductive brush roller including a roller having a shaft; and hair located overlying the roller, wherein the hair includes a fiber which has a width of from 0.1 to 20 denier, and a length of from 0.3 to 2.5 mm and which is planted at a density of from 7,000 to 46,000 lines/cm2, and a member configured to impart substantially the same potential as that of the charging roller to the electroconductive brush roller when a bias voltage is applied to the charging roller. A process cartridge and an image forming apparatus including the charging device are also provided.Type: ApplicationFiled: June 30, 2006Publication date: January 18, 2007Inventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Tokuya Ohjimi, Masami Tomita, Takeshi Shintani
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Patent number: 7139504Abstract: A charging device including: a charging roller having a metal cylinder and an elastic layer located on the metal cylinder; a cleaner configured to clean the charging roller, which includes an electroconductive brush roller including a roller having a shaft; and hair located overlying the roller, wherein the hair includes a fiber which has a width of from 0.1 to 20 denier, and a length of from 0.3 to 2.5 mm and which is planted at a density of from 7,000 to 46,000 lines/cm2, and a member configured to impart substantially the same potential as that of the charging roller to the electroconductive brush roller when a bias voltage is applied to the charging roller. A process cartridge and an image forming apparatus including the charging device are also provided.Type: GrantFiled: February 11, 2004Date of Patent: November 21, 2006Assignee: Ricoh Company LimitedInventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Tokuya Ohjimi, Masami Tomita, Takeshi Shintani
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Publication number: 20060216085Abstract: A cleaning unit includes a first blade and a second blade. The first blade is in contact with an image carrier or a paper carrier and removes adhered substances remained on surface of these. The second blade has an abrasive layer that is formed by including abrasive particles in an elastic material and is disposed in the downstream side of the first blade. The second blade is allowed to be in contact with the image carrier 1 or the paper carrier. Volume occupancy of abrasive particles in an area of contact of the second blade with either the image carrier or the paper carrier is not less than 50 percent and not more than 90 percent.Type: ApplicationFiled: May 26, 2006Publication date: September 28, 2006Inventors: Eisaku Murakami, Masami Tomita, Masanori Kawasumi, Toshio Koike, Naohiro Kumagai, Atsushi Sampe, Takeshi Shintani, Masato Yanagida, Yutaka Takahashi, Hiroya Hirose, Shin Hasegawa, Hiroyuki Nagashima, Takeshi Uchitani, Kazunori Karasawa, Kentaroh Matsumoto, Tokuya Ohjimi, Mugijiroh Uno
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Patent number: 7110696Abstract: A cleaning unit includes a first blade and a second blade. The first blade is in contact with an image carrier or a paper carrier and removes adhered substances remained on surface of these. The second blade has an abrasive layer that is formed by including abrasive particles in an elastic material and is disposed in the downstream side of the first blade. The second blade is allowed to be in contact with the image carrier 1 or the paper carrier. Volume occupancy of abrasive particles in an area of contact of the second blade with either the image carrier or the paper carrier is not less than 50 percent and not more than 90 percent.Type: GrantFiled: September 24, 2003Date of Patent: September 19, 2006Assignee: Ricoh Company, Ltd.Inventors: Eisaku Murakami, Masami Tomita, Masanori Kawasumi, Toshio Koike, Naohiro Kumagai, Atsushi Sampe, Takeshi Shintani, Masato Yanagida, Yutaka Takahashi, Hiroya Hirose, Shin Hasegawa, Hiroyuki Nagashima, Takeshi Uchitani, Kazunori Karasawa, Kentaroh Matsumoto, Tokuya Ohjimi, Mugijiroh Uno
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Patent number: 6873814Abstract: A developing device including a developer containing magnetic toner grains and includes a main pole for development disposed in a sleeve. Flux density generated by the magnetic pole in a direction normal to the surface of the sleeve outside of the surface has an attenuation ratio of 50% or above. The toner grains have a weight mean grain size of 6.0 ?m to 8.0 ?m while the toner grains having grain sizes of 5 ?m and below occupy 40% to 80% of the entire developer. The toner grains have magnetization strength of 10 emu/g to 25 emu/g in a magnetic field of 5 kOe or magnetization strength of 7 emu/g to 20 emu/g in a magnetic field of 1 kOe. The toner grains reduce toner scattering and image defects despite that they are magnetic, thereby implementing ultrahigh resolution.Type: GrantFiled: November 1, 2002Date of Patent: March 29, 2005Assignee: Ricoh Company, Ltd.Inventors: Tokuya Ohjimi, Fumihiro Sasaki, Hiroto Higuchi, Maiko Kondo, Toshio Koike, Atsushi Sampe, Masayuki Yamane, Kunihiro Ohyama, Junichi Sano, Takeyoshi Sekine
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Patent number: 6856774Abstract: A developing device developing a latent image on a latent image carrier with a developer, and including a casing having an opening facing the latent image carrier and a developer carrier. Also included is a magnetic field generating device including a first magnetic pole generating a magnetic field causing the developer to rise on the developer carrier in a form of a magnet brush in a developing region, and a second magnetic pole generating a magnetic field at a downstream side of the first magnetic pole in a rotating direction of the developer carrier. Further, a toner-scattering restraining device is provided on an end portion of the casing at the downstream side of the developing region, and a magnetic member provided on a side of the toner-scattering restraining device facing the latent image carrier. A peak of a magnetic flux density set by the second magnetic pole in its normal direction is located outside of the opening.Type: GrantFiled: November 26, 2002Date of Patent: February 15, 2005Assignee: Ricoh Company, Ltd.Inventors: Atsushi Sampe, Takeyoshi Sekine, Masayuki Yamane, Tokuya Ohjimi, Junichi Sano, Toshio Koike, Fumihiro Sasaki, Hiroto Higuchi, Maiko Kondo, Kunihiro Ohyama
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Publication number: 20040213597Abstract: A charging device including: a charging roller having a metal cylinder and an elastic layer located on the metal cylinder; a cleaner configured to clean the charging roller, which includes an electroconductive brush roller including a roller having a shaft; and hair located overlying the roller, wherein the hair includes a fiber which has a width of from 0.1 to 20 denier, and a length of from 0.3 to 2.5 mm and which is planted at a density of from 7,000 to 46,000 lines/cm2, and a member configured to impart substantially the same potential as that of the charging roller to the electroconductive brush roller when a bias voltage is applied to the charging roller. A process cartridge and an image forming apparatus including the charging device are also provided.Type: ApplicationFiled: February 11, 2004Publication date: October 28, 2004Inventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Tokuya Ohjimi, Masami Tomita, Takeshi Shintani
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Publication number: 20040136763Abstract: A cleaning unit includes a first blade and a second blade. The first blade is in contact with an image carrier or a paper carrier and removes adhered substances remained on surface of these. The second blade has an abrasive layer that is formed by including abrasive particles in an elastic material and is disposed in the downstream side of the first blade. The second blade is allowed to be in contact with the image carrier 1 or the paper carrier. Volume occupancy of abrasive particles in an area of contact of the second blade with either the image carrier or the paper carrier is not less than 50 percent and not more than 90 percent.Type: ApplicationFiled: September 24, 2003Publication date: July 15, 2004Inventors: Eisaku Murakami, Masami Tomita, Masanori Kawasumi, Toshio Koike, Naohiro Kumagai, Atsushi Sampe, Takeshi Shintani, Masato Yanagida, Yutaka Takahashi, Hiroya Hirose, Shin Hasegawa, Hiroyuki Nagashima, Takeshi Uchitani, Kazunori Karasawa, Kentaroh Matsumoto, Tokuya Ohjimi, Mugijiroh Uno
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Patent number: 6687474Abstract: A developing apparatus, an image formation apparatus and a process cartridge is provided. Even though the sealing materials of the initial developer container are stripped off in such a way that the process cartridge having the developing apparatus is tilted, the initial developer can be uniformly supplied along the central axis line of the developer carrier. The developing apparatus performs a self toner control and has an initial developer case 10 for containing the non-used initial developer 3c that is input into the developer containing space S. The initial developer case 10 is divided internally into a plurality of partition spaces 10b along the direction of the central axial line D of the developing sleeve 4, so that a plurality of partitions 10c is formed inside the initial developer case 10.Type: GrantFiled: June 7, 2002Date of Patent: February 3, 2004Assignee: Ricoh Company, Ltd.Inventors: Masahiko Yamada, Kentaroh Matsumoto, Hiroyuki Nagashima, Tokuya Ohjimi
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Publication number: 20030108362Abstract: A developing device of the present invention uses a developer containing magnetic toner grains and includes a main pole for development disposed in a sleeve. Flux density generated by the magnetic pole in a direction normal to the surface of the sleeve outside of the surface has an attenuation ratio of 50% or above. The toner grains have a weight mean grain size of 6.0 &mgr;m to 8.0 &mgr;m while the toner grains having grain sizes of 5 &mgr;m and below occupy 40 number % to 80 number % of the entire developer. The toner grains have magnetization strength of 10 emu/g to 25 emu/g in a magnetic field of 5 kOe or magnetization strength of 7 emu/g to 20 emu/g in a magnetic field of 1 kOe. The toner grains reduce toner scattering and image defects despite that they are magnetic, thereby implementing ultrahigh resolution, image reproducibility.Type: ApplicationFiled: November 1, 2002Publication date: June 12, 2003Inventors: Tokuya Ohjimi, Fumihiro Sasaki, Hiroto Higuchi, Maiko Kondo, Toshio Koike, Atsushi Sampe, Masayuki Yamane, Kunihiro Ohyama, Junichi Sano, Takeyoshi Sekine
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Publication number: 20030099481Abstract: A developing device developing a latent image on a latent image carrier with a developer, and including a casing having an opening facing the latent image carrier and a developer carrier. Also included is a magnetic field generating device including a first magnetic pole generating a magnetic field causing the developer to rise on the developer carrier in a form of a magnet brush in a developing region, and a second magnetic pole generating a magnetic field at a downstream side of the first magnetic pole in a rotating direction of the developer carrier. Further, a toner-scattering restraining device is provided on an end portion of the casing at the downstream side of the developing region, and a magnetic member provided on a side of the toner-scattering restraining device facing the latent image carrier. A peak of a magnetic flux density set by the second magnetic pole in its normal direction is located outside of the opening.Type: ApplicationFiled: November 26, 2002Publication date: May 29, 2003Inventors: Atsushi Sampe, Takeyoshi Sekine, Masayuki Yamane, Tokuya Ohjimi, Junichi Sano, Toshio Koike, Fumihiro Sasaki, Hiroto Higuchi, Maiko Kondo, Kunihiro Ohyama
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Patent number: 6507718Abstract: In an image forming apparatus having a reverse development system and using a two-component developer, respective potentials applied when charging an image bearing member and when applying a development bias to a developer bearing member are attenuated when the image bearing member is driven for an operation other than an image forming operation, compared to respective level of potentials applied when the image bearing member is driven for the image forming operation. Thus, an occurrence of an adhesion of a carrier to an image bearing member is reduced to produce a high quality image, when a power switch of the apparatus is turned off or when a door of the apparatus is opened while the image bearing member is driven for an operation other than the image forming operation, or when the apparatus is activated again after the power switch is turned off.Type: GrantFiled: August 31, 2001Date of Patent: January 14, 2003Assignee: Ricoh Company, Ltd.Inventors: Tokuya Ohjimi, Kentaroh Matsumoto
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Publication number: 20030002884Abstract: A developing apparatus, an image formation apparatus and a process cartridge is provided. Even though the sealing materials of the initial developer container are stripped off in such a way that the process cartridge having the developing apparatus is tilted, the initial developer can be uniformly supplied along the central axis line of the developer carrier. The developing apparatus performs a self toner control and has an initial developer case 10 for containing the non-used initial developer 3c that is input into the developer containing space S. The initial developer case 10 is divided internally into a plurality of partition spaces 10b along the direction of the central axial line D of the developing sleeve 4, so that a plurality of partitions 10c is formed inside the initial developer case 10.Type: ApplicationFiled: June 7, 2002Publication date: January 2, 2003Inventors: Masahiko Yamada, Kentaroh Matsumoto, Hiroyuki Nagashima, Tokuya Ohjimi