Patents by Inventor Yuji Nagatomo

Yuji Nagatomo 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).

  • Patent number: 10036976
    Abstract: A developing device includes a developer bearer facing a latent image bearer, to rotate and supply developer to the latent image bearer, and a developer regulator to regulate an amount of the developer on a surface of the developer bearer. The developer regulator is in contact with the surface of the developer bearer. In the developing device, a ratio of a ten-point mean roughness of the developer regulator to a volume average particle diameter of the developer is not greater than 3.5%. The ratio is defined as Rzjis/Dv×100, where Rzjis represents the ten-point mean roughness measured in a nip-adjacent portion of a face of the developer regulator opposing the developer bearer, and Dv represents the volume average particle diameter of the developer. The nip-adjacent portion is adjacent to and downstream a downstream end of a regulation nip in a rotation direction of the developer bearer.
    Type: Grant
    Filed: December 2, 2016
    Date of Patent: July 31, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Yuji Nagatomo, Tetsumaru Fujita, Masato Tsuji, Yutaro Kaku
  • Patent number: 9958806
    Abstract: A developing device includes a toner bearer to rotate while bearing toner and a toner regulator including a bend on a free end side. The bend is disposed in contact with a surface of the toner bearer and defines a regulation nip to adjust an amount of the toner on the toner bearer. The toner regulator further includes an area having a water contact angle greater than or equal to 70 degrees. The area having the water contact angle includes, at least, a downstream end of the bend in a rotation direction of the toner bearer.
    Type: Grant
    Filed: November 8, 2016
    Date of Patent: May 1, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Masato Tsuji, Tetsumaru Fujita, Yuji Nagatomo, Mitsutoshi Kichise, Yutaro Kaku, Kazuki Matsumoto
  • Publication number: 20170176886
    Abstract: A developing device includes a developer bearer facing a latent image bearer, to rotate and supply developer to the latent image bearer, and a developer regulator to regulate an amount of the developer on a surface of the developer bearer. The developer regulator is in contact with the surface of the developer bearer. In the developing device, a ratio of a ten-point mean roughness of the developer regulator to a volume average particle diameter of the developer is not greater than 3.5%. The ratio is defined as Rzjis/Dv×100, where Rzjis represents the ten-point mean roughness measured in a nip-adjacent portion of a face of the developer regulator opposing the developer bearer, and Dv represents the volume average particle diameter of the developer. The nip-adjacent portion is adjacent to and downstream a downstream end of a regulation nip in a rotation direction of the developer bearer.
    Type: Application
    Filed: December 2, 2016
    Publication date: June 22, 2017
    Applicant: Ricoh Company, Ltd.
    Inventors: Yuji NAGATOMO, Tetsumaru Fujita, Masato Tsuji, Yutaro Kaku
  • Publication number: 20170146925
    Abstract: A developing device includes a toner bearer to rotate while bearing toner and a toner regulator including a bend on a free end side. The bend is disposed in contact with a surface of the toner bearer and defines a regulation nip to adjust an amount of the toner on the toner bearer. The toner regulator further includes an area having a water contact angle greater than or equal to 70 degrees. The area having the water contact angle includes, at least, a downstream end of the bend in a rotation direction of the toner bearer.
    Type: Application
    Filed: November 8, 2016
    Publication date: May 25, 2017
    Inventors: Masato TSUJI, Tetsumaru FUJITA, Yuji NAGATOMO, Mitsutoshi KICHISE, Yutaro KAKU, Kazuki MATSUMOTO
  • Patent number: 9551956
    Abstract: An image forming apparatus is provided. The image forming apparatus includes a photoconductor, an irradiator, a developing device including a developing roller, a development bias applying device, a toner supplying roller and a supply bias applying device, and a controller. The controller changes supply bias offset by reference to at least one of five parameters including photoconductor travel distance, operation temperature of the developing device, operation humidity of the developing device, continuous operating time of the developing device, and color information of image to be produced. After changing the supply bias offset, the controller forms plural toner patterns for image density adjustment on the photoconductor by changing the development bias, and sets the development bias to a certain bias based on the image densities of the plural toner patterns so that the image produced by the developing device has a targeted image density.
    Type: Grant
    Filed: January 15, 2016
    Date of Patent: January 24, 2017
    Assignee: Ricoh Company, Ltd.
    Inventors: Kyoko Abe, Yuji Nagatomo, Shintaro Yamada, Shinji Aoki
  • Publication number: 20160209774
    Abstract: An image forming apparatus is provided. The image forming apparatus includes a photoconductor, an irradiator, a developing device including a developing roller, a development bias applying device, a toner supplying roller and a supply bias applying device, and a controller. The controller changes supply bias offset by reference to at least one of five parameters including photoconductor travel distance, operation temperature of the developing device, operation humidity of the developing device, continuous operating time of the developing device, and color information of image to be produced. After changing the supply bias offset, the controller forms plural toner patterns for image density adjustment on the photoconductor by changing the development bias, and sets the development bias to a certain bias based on the image densities of the plural toner patterns so that the image produced by the developing device has a targeted image density.
    Type: Application
    Filed: January 15, 2016
    Publication date: July 21, 2016
    Applicant: Ricoh Company, Ltd.
    Inventors: Kyoko Abe, Yuji Nagatomo, Shintaro Yamada, Shinji Aoki
  • Patent number: 9335663
    Abstract: A seal is provided to contact a rotating body installed in an image forming apparatus. Pencil hardness of the sealing element is about 2H or more and a water drop contact angle thereof is about 90 degrees or more.
    Type: Grant
    Filed: January 5, 2015
    Date of Patent: May 10, 2016
    Assignee: Ricoh Company, Ltd.
    Inventors: Kyoko Abe, Tomohiro Kubota, Takahiro Sanada, Yuji Nagatomo
  • Patent number: 9116460
    Abstract: An image forming apparatus includes a latent image forming device that forms a latent image, a latent image carrier that carries the latent image, a development device that develops the latent image, and a controller. The development device includes a developer carrier that faces the latent image carrier and carries toner on a rotary surface thereof that rotates in a rotation direction perpendicular to a width direction of the developer carrier, and a regulation member that regulates the thickness of a layer of the toner on the surface of the developer carrier. The controller moves the toner on lateral end regions in the width direction of the surface of the developer carrier toward the latent image carrier. The end regions are located outside a maximum image forming region within a regulation member facing region of the surface of the developer carrier facing the regulation member.
    Type: Grant
    Filed: November 27, 2013
    Date of Patent: August 25, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasuhide Matsuno, Naoki Nakatake, Yuji Nagatomo, Takahiro Sanada
  • Publication number: 20150192882
    Abstract: A seal is provided to contact a rotating body installed in an image forming apparatus. Pencil hardness of the sealing element is about 2H or more and a water drop contact angle thereof is about 90 degrees or more.
    Type: Application
    Filed: January 5, 2015
    Publication date: July 9, 2015
    Applicant: Ricoh Company, Ltd.
    Inventors: Kyoko Abe, Tomohiro Kubota, Takahiro Sanada, Yuji Nagatomo
  • Patent number: 8983323
    Abstract: Provided is a color image forming apparatus that includes: image carriers that form toner image of black and other colors; an intermediate transfer body that makes contact with the image carriers; and transfer units that transfer the toner images on the image carriers to the intermediate transfer body. A line velocity difference is set between the image carriers and the intermediate transfer body. An accelerated cohesion degree of toner is equal to or larger than 54%. A linear velocity difference X1 between the image carrier for black and the intermediate transfer body satisfies a relation of 0<X1?1.2 mm/sec. A linear velocity difference X2 between the image carriers for the colors and the intermediate transfer body satisfies a relation of 2.1?X2?4.0 mm/sec.
    Type: Grant
    Filed: January 25, 2013
    Date of Patent: March 17, 2015
    Assignee: Ricoh Company, Limited
    Inventors: Takeshi Yamashita, Yuji Nagatomo, Naoki Nakatake, Yasuhiro Fujiwara, Takafumi Miyazaki, Yasuhide Matsuno, Takahiro Sanada, Rumi Miyazaki, Kyoko Abe, Tomoya Adachi, Yoshie Iwakura
  • Patent number: 8977150
    Abstract: An image forming apparatus includes a rotatable photoconductor, a charging unit, an exposure unit to expose the photoconductor to reduce an electrical potential at the photoconductor, a developing unit to charge the toner held on a toner bearing member with friction and attract the toner to the exposed portion on the photoconductor by supplying a development voltage from a first power source and using an electrical potential difference between the toner bearing member and the photoconductor in the development area, a reverse development voltage controller to supply a reverse development voltage while a non-charged portion on the photoconductor passes the development area, and a developer reducing potential applier to supply a development restraining potential and an absolute value smaller than a target charging potential to the photoconductor while the reverse development voltage is supplied.
    Type: Grant
    Filed: November 15, 2012
    Date of Patent: March 10, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Shin Yamamoto, Shin Murayama, Yoshio Sakagawa, Yuji Nagatomo
  • Patent number: 8971743
    Abstract: An image forming apparatus including a latent image bearing member, a charger, a latent image forming device, a developing device, and a transfer device is provided. The transfer device is adapted to transfer a toner image formed on the latent image bearing member onto an intermediate transfer member or a recording medium by action of a transfer elected field in a transfer position where the latent image bearing member faces the transfer device. When a non-charged portion of the latent image bearing member that has not been charged to a predetermined potential by the charger passes through the transfer position, a strength of the transfer electric field is lowered than that in transferring the toner image.
    Type: Grant
    Filed: March 25, 2013
    Date of Patent: March 3, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Takafumi Miyazaki, Naoki Nakatake, Yuji Nagatomo, Yasuhide Matsuno, Takahiro Sanada, Yasuhiro Fujiwara, Kyoko Abe, Takeshi Yamashita, Tomoya Adachi
  • Patent number: 8867971
    Abstract: A developer regulator to restrict an amount of a developer, including a base portion; an intermediate portion continuous with the base portion, the intermediate portion having a flat area on one face, the flat area having a roughened surface; and a distal end continuous with the intermediate portion, the distal end being bent relative to the base portion in a direction opposite the one face in which the flat area is formed.
    Type: Grant
    Filed: August 15, 2011
    Date of Patent: October 21, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuji Inoue, Yuji Nagatomo, Yasuhide Matsuno
  • Patent number: 8805222
    Abstract: An image developing device includes a developer supporting body; a first conveyance path in which a first conveyance member is arranged; a second conveyance path in which a second conveyance member is arranged; and a partition member that partitions the first conveyance path and the second conveyance path and that has a first communication port and a second communication port. The first communication path and the second communication path communicates with each other through the first communication port and the second communication port. The image developing device includes a developer amount detection unit that includes an optical detection unit arranged in the second conveyance path and that optically detects an amount of the developer in the image forming device. The developer is caused to accumulate in the vicinity of the developer amount detection unit.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: August 12, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoki Nakatake, Tomohiro Kubota, Shoh Tsuritani, Yuji Nagatomo, Yasuhide Matsuno, Hiroaki Katoh, Tomoya Adachi, Rumi Miyazaki, Takafumi Miyazaki, Takeshi Yamashita, Kyoko Abe, Yasuhiro Fujiwara, Takahiro Sanada
  • Publication number: 20140161471
    Abstract: An image forming apparatus includes a latent image forming device that forms a latent image, a latent image carrier that carries the latent image, a development device that develops the latent image, and a controller. The development device includes a developer carrier that faces the latent image carrier and carries toner on a rotary surface thereof that rotates in a rotation direction perpendicular to a width direction of the developer carrier, and a regulation member that regulates the thickness of a layer of the toner on the surface of the developer carrier. The controller moves the toner on lateral end regions in the width direction of the surface of the developer carrier toward the latent image carrier. The end regions are located outside a maximum image forming region within a regulation member facing region of the surface of the developer carrier facing the regulation member.
    Type: Application
    Filed: November 27, 2013
    Publication date: June 12, 2014
    Applicant: Ricoh Company, Ltd
    Inventors: Yasuhide Matsuno, Naoki Nakatake, Yuji Nagatomo, Takahiro Sanada
  • Publication number: 20130266332
    Abstract: An image forming apparatus including a latent image bearing member, a charger, a latent image forming device, a developing device, and a transfer device is provided. The transfer device is adapted to transfer a toner image formed on the latent image bearing member onto an intermediate transfer member or a recording medium by action of a transfer elected field in a transfer position where the latent image bearing member faces the transfer device. When a non-charged portion of the latent image bearing member that has not been charged to a predetermined potential by the charger passes through the transfer position, a strength of the transfer electric field is lowered than that in transferring the toner image.
    Type: Application
    Filed: March 25, 2013
    Publication date: October 10, 2013
    Inventors: Takafumi MIYAZAKI, Naoki NAKATAKE, Yuji NAGATOMO, Yasuhide MATSUNO, Takahiro SANADA, Yasuhiro FUJIWARA, Kyoko ABE, Takeshi YAMASHITA, Tomoya ADACHI
  • Publication number: 20130236217
    Abstract: A development device to develop a latent image using developer having a degree of agglomeration of 54% or greater includes a developer bearer to carry developer thereon, and a developer supply member to contact the developer bearer to supply developer to a surface of the developer bearer. The developer supply member is disposed to satisfy at least one of two conditions: a biting amount of the developer supply member relative to the developer bearer is 0.7 mm or greater; and a contact pressure of the developer supply member against the developer bearer is 30 N/m or greater.
    Type: Application
    Filed: March 12, 2013
    Publication date: September 12, 2013
    Inventors: Yuji NAGATOMO, Yasuhide Matsuno, Takahiro Sanada, Naoki Nakatake, Takafumi Miyazaki, Yasuhiro Fujiwara, Kyoko Abe, Rumi Miyazaki, Takeshi Yamashita, Tomoya Adachi
  • Publication number: 20130195487
    Abstract: Provided is a color image forming apparatus that includes: image carriers that form toner image of black and other colors; an intermediate transfer body that makes contact with the image carriers; and transfer units that transfer the toner images on the image carriers to the intermediate transfer body. A line velocity difference is set between the image carriers and the intermediate transfer body. An accelerated cohesion degree of toner is equal to or larger than 54%. A linear velocity difference X1 between the image carrier for black and the intermediate transfer body satisfies a relation of 0<X1?1.2 mm/sec. A linear velocity difference X2 between the image carriers for the colors and the intermediate transfer body satisfies a relation of 2.1?X2?4.0 mm/sec.
    Type: Application
    Filed: January 25, 2013
    Publication date: August 1, 2013
    Inventors: Takeshi YAMASHITA, Yuji NAGATOMO, Naoki NAKATAKE, Yasuhiro FUJIWARA, Takafumi MIYAZAKI, Yasuhide MATSUNO, Takahiro SANADA, Rumi MIYAZAKI, Kyoko ABE, Tomoya ADACHI, Yoshie IWAKURA
  • Publication number: 20130142530
    Abstract: An image forming apparatus includes a rotatable photoconductor, a charging unit, an exposure unit to expose the photoconductor to reduce an electrical potential at the photoconductor, a developing unit to charge the toner held on a toner bearing member with friction and attract the toner to the exposed portion on the photoconductor by supplying a development voltage from a first power source and using an electrical potential difference between the toner bearing member and the photoconductor in the development area, a reverse development voltage controller to supply a reverse development voltage while a non-charged portion on the photoconductor passes the development area, and a developer reducing potential applier to supply a development restraining potential and an absolute value smaller than a target charging potential to the photoconductor while the reverse development voltage is supplied.
    Type: Application
    Filed: November 15, 2012
    Publication date: June 6, 2013
    Inventors: Shin YAMAMOTO, Shin MURAYAMA, Yoshio SAKAGAWA, Yuji NAGATOMO
  • Patent number: 8406664
    Abstract: An image forming apparatus includes a plurality of image carriers, a latent image forming unit, and a plurality of developing units. Each of the developing unit forms an image to have a color difference of equal to or less than about five with respect to an initial unicolor image formed by using a toner not containing a reversely-transferred toner of another color when a toner contained in a toner container is consumed by about 70%.
    Type: Grant
    Filed: September 4, 2008
    Date of Patent: March 26, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Tetsumaru Fujita, Yuji Nagatomo