Patents by Inventor Yasushi Koichi

Yasushi Koichi 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: 7840152
    Abstract: A transfer residual toner that has not been electrostatically transferred onto a transfer paper P at a transfer nip and remains on a surface of a photosensitive element is temporarily retained by an elastic blade of a toner retaining unit in a mechanical manner before reaching a latent image forming area. When passing through the latent image forming area, the transfer residual toner is returned onto the surface of the photosensitive member at such a timing that writing is not performed by an exposing unit on the surface of the photosensitive element.
    Type: Grant
    Filed: January 2, 2009
    Date of Patent: November 23, 2010
    Assignee: Ricoh Company, Limited
    Inventors: Yasushi Koichi, Koji Suzuki, Shigekazu Enoki, Osamu Ariizumi, Kumiko Hatakeyama
  • Patent number: 7639957
    Abstract: An image forming apparatus includes an image carrier, a developing unit, a concentration sensor, a toner supplying unit, a developer supplying unit, an ejector, and a condition detector. The image carrier forms a latent image thereon. The developing unit develops the latent image formed on the image carrier with a two-component image developer including toner particles and carrier particles. The concentration sensor detects a toner ratio in the developing unit. The toner supplying unit supplies fresh toner particles to the developing unit. The developer supplying unit supplies fresh image developer to the developing unit. The ejector ejects the image developer to an outside of the developing unit. The condition detector detects a condition of the image developer used for an image forming operation to determine a supply amount of the image developer to supply to the developing unit. The condition includes a degradation level of the image developer.
    Type: Grant
    Filed: April 20, 2007
    Date of Patent: December 29, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinji Kato, Koji Suzuki, Yasushi Koichi, Shigekazu Enoki, Wakako Murakami, Kumiko Hatakeyama
  • Patent number: 7548349
    Abstract: In an image forming apparatus configured to electrostatically transfer a toner image formed on an image carrier to a recording medium with image transferring means of the present invention, pressure is applied between the image carrier and the image transferring means. Toner is provided with relatively high hardness in accordance with the pressure beforehand. Image transfer is effected by reducing a potential difference between the image carrier and the recording medium while maintaining an electric field around the toner the same.
    Type: Grant
    Filed: August 29, 2003
    Date of Patent: June 16, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasushi Koichi, Mitsuo Aoki, Bing Shu, Koji Suzuki, Shigeru Watanabe, Tadashi Kasai, Yutaka Takahashi
  • Publication number: 20090116863
    Abstract: A transfer residual toner that has not been electrostatically transferred onto a transfer paper P at a transfer nip and remains on a surface of a photosensitive element is temporarily retained by an elastic blade of a toner retaining unit in a mechanical manner before reaching a latent image forming area. When passing through the latent image forming area, the transfer residual toner is returned onto the surface of the photosensitive member at such a timing that writing is not performed by an exposing unit on the surface of the photosensitive element.
    Type: Application
    Filed: January 2, 2009
    Publication date: May 7, 2009
    Inventors: Yasushi KOICHI, Koji Suzuki, Shigekazu Enoki, Osamu Ariizumi, Kumiko Hatakeyama
  • Patent number: 7515860
    Abstract: An image forming apparatus comprising: a latent image support for supporting a latent image and a developing device configured to us toner to develop the latent image on said latent image support, the estimated average halftone granularity of the toner imager after developing being 0.25 or less.
    Type: Grant
    Filed: August 2, 2007
    Date of Patent: April 7, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Koji Suzuki, Mitsuo Aoki, Bing Shu, Yasushi Koichi, Setsuo Soga, Tadashi Kasai, Yutaka Takahashi
  • Patent number: 7499664
    Abstract: A transfer residual toner that has not been electrostatically transferred onto a transfer paper P at a transfer nip and remains on a surface of a photosensitive element is temporarily retained by an elastic blade of a toner retaining unit in a mechanical manner before reaching a latent image forming area. When passing through the latent image forming area, the transfer residual toner is returned onto the surface of the photosensitive member at such a timing that writing is not performed by an exposing unit on the surface of the photosensitive element.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: March 3, 2009
    Assignee: Ricoh Company, Limited
    Inventors: Yasushi Koichi, Koji Suzuki, Shigekazu Enoki, Osamu Ariizumi, Kumiko Hatakeyama
  • Patent number: 7315711
    Abstract: An image forming apparatus of includes a developing device bifunctioning as a cleaning device for collecting toner grains left on a photoconductive drum after the transfer of a toner image from the drum to a paper sheet or similar image transfer medium. In the event of toner collection, a DC voltage is applied that causes the residual toner to move from the drum toward a developing sleeve. A main-pole magnet generates, at a position where the developing sleeve faces the drum, a magnetic field of between 100 mT and 200 mT in a direction normal to the surface of the sleeve.
    Type: Grant
    Filed: June 13, 2005
    Date of Patent: January 1, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Osamu Ariizumi, Masahide Yamashita, Koji Suzuki, Yasushi Koichi, Shigekazu Enoki, Kumiko Hatakeyama, Koichi Kato, Toshiyuki Kabata, Jun Yura
  • Publication number: 20070286652
    Abstract: An image forming apparatus comprising: a latent image support for supporting a latent image and a developing device configured to us toner to develop the latent image on said latent image support, the estimated average halftone granularity of the toner imager after developing being 0.25 or less.
    Type: Application
    Filed: August 2, 2007
    Publication date: December 13, 2007
    Inventors: Koji SUZUKI, Mitsuo Aoki, Bing Shu, Yasushi Koichi, Setsuo Soga, Tadashi Kasai, Yutaka Takahashi
  • Publication number: 20070248368
    Abstract: An image forming apparatus includes an image carrier, a developing unit, a concentration sensor, a toner supplying unit, a developer supplying unit, an ejector, and a condition detector. The image carrier forms a latent image thereon. The developing unit develops the latent image formed on the image carrier with a two-component image developer including toner particles and carrier particles. The concentration sensor detects a toner ratio in the developing unit. The toner supplying unit supplies fresh toner particles to the developing unit. The developer supplying unit supplies fresh image developer to the developing unit. The ejector ejects the image developer to an outside of the developing unit. The condition detector detects a condition of the image developer used for an image forming operation to determine a supply amount of the image developer to supply to the developing unit. The condition includes a degradation level of the image developer.
    Type: Application
    Filed: April 20, 2007
    Publication date: October 25, 2007
    Inventors: Shinji Kato, Koji Suzuki, Yasushi Koichi, Shigekazu Enoki, Wakako Murakami, Kumiko Hatakeyama
  • Patent number: 7273688
    Abstract: An electrophotographic image forming apparatus capable of reliably forming an image with density gradation, one which does not have a low-quality appearance. The estimated average halftone granularity of the toner image after developing but before electrostatic transfer was set at 0.25 or less. The average halftone granularity was found by measuring the granularity of a toner image at locations of different average brightness by means of newly proposed formula, and averaging the measured values for which the average brightness is 40 to 80. The estimated average halftone granularity was obtained by estimating the average halftone granularity of the toner image on a photoreceptor by means of a newly proposed method.
    Type: Grant
    Filed: August 14, 2006
    Date of Patent: September 25, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Koji Suzuki, Mitsuo Aoki, Bing Shu, Yasushi Koichi, Setsuo Soga, Tadashi Kasai, Yutaka Takahashi
  • Patent number: 7218879
    Abstract: An image forming apparatus includes an image carrier, a charging device configured to uniformly charge a surface of the image carrier with a charging member applied with a bias of a first polarity (e.g. a negative polarity) for charging. A latent image forming device forms a latent image on the surface of the image carrier uniformly charged. A developing device develops a latent image by depositing toner grains of the first polarity on the latent image to thereby form a corresponding toner image. A transferring device forms an electric field between the image carrier and a moving member that serves as a movable contact with the image carrier to thereby transfer the toner image from the surface of the image carrier to the moving member or to a recording member nipped between the image carrier and the moving member. A polarity controlling device sets residual toner to a second polarity (e.g.
    Type: Grant
    Filed: December 3, 2004
    Date of Patent: May 15, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigekazu Enoki, Koji Suzuki, Yasushi Koichi, Osamu Ariizumi, Kumiko Hatakeyama, Koichi Kato, Masahide Yamashita, Toshiyuki Kabata, Jun Yura
  • Patent number: 7162187
    Abstract: In an image forming apparatus, a toner image is formed on a photosensitive element and a transfer roller, which carries a transfer medium, is pressed against a photosensitive element at a pressure of from 20.4 N/cm2 to 200 N/cm2.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: January 9, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasushi Koichi, Mitsuo Aoki, Bing Shu, Setsuo Soga, Koji Suzuki, Yutaka Takahashi, Tadashi Kasai
  • Patent number: 7150954
    Abstract: An image forming method, comprising passing a toner image-bearing sheet through a nip defined between two rollers including a heater roller to fix the toner image on the sheet, wherein the toner image is formed from a toner comprising a binder resin, and a colorant, wherein the toner image before the passage through the nip has a toner volume V1 and a toner image area S1, wherein the toner image after the passage through the nip has a toner volume V2 and a toner image area S2, and wherein a volume change Vt and an area change St defined by the formulas shown below are 30% or less and 20% or less, respectively: Vt(%)=(V1?V2)/V1×100 St(%)=(S2?S1)/S1×100. Alternatively, the toner image before the passage through the nip has a surface roughness of 2.5 ?m or less.
    Type: Grant
    Filed: December 3, 2004
    Date of Patent: December 19, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuo Aoki, Kumi Hasegawa, Toshiaki Higaya, Yasushi Koichi, Yutaka Takahashi, Tadashi Kasai
  • Publication number: 20060275688
    Abstract: An electrophotographic image forming apparatus capable of reliably forming an image with density gradation, one which does not have a low-quality appearance. The estimated average halftone granularity of the toner image after developing but before electrostatic transfer was set at 0.25 or less. The average halftone granularity was found by measuring the granularity of a toner image at locations of different average brightness by means of newly proposed formula, and averaging the measured values for which the average brightness is 40 to 80. The estimated average halftone granularity was obtained by estimating the average halftone granularity of the toner image on a photoreceptor by means of a newly proposed method.
    Type: Application
    Filed: August 14, 2006
    Publication date: December 7, 2006
    Inventors: Koji Suzuki, Mitsuo Aoki, Bing Shu, Yasushi Koichi, Setsuo Soga, Tadashi Kasai, Yutaka Takahashi
  • Patent number: 7125638
    Abstract: An electrophotographic image forming apparatus capable of reliably forming an image with density gradation, one which does not have a low-quality appearance. The estimated average halftone granularity of the toner image after developing but before electrostatic transfer was set at 0.25 or less. The average halftone granularity was found by measuring the granularity of a toner image at locations of different average brightness by means of newly proposed formula, and averaging the measured values for which the average brightness is 40 to 80. The estimated average halftone granularity was obtained by estimating the average halftone granularity of the toner image on a photoreceptor by means of a newly proposed method.
    Type: Grant
    Filed: March 23, 2004
    Date of Patent: October 24, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Koji Suzuki, Mitsuo Aoki, Bing Shu, Yasushi Koichi, Setsuo Soga, Tadashi Kasai, Yutaka Takahashi
  • Publication number: 20050276632
    Abstract: An image forming apparatus of the present invention includes a developing device bifunctioning as a cleaning device for collecting toner grains left on a photoconductive drum after the transfer of a toner image from the drum to a paper sheet or similar image transfer medium. In the event of toner collection, a DC voltage is applied that causes the residual toner to move from the drum toward a developing sleeve. A main-pole magnet generates, at a position where the developing sleeve faces the drum, a magnetic field of between 100 mT and 200 mT in a direction normal to the surface of the sleeve.
    Type: Application
    Filed: June 13, 2005
    Publication date: December 15, 2005
    Inventors: Osamu Ariizumi, Masahide Yamashita, Koji Suzuki, Yasushi Koichi, Shigekazu Enoki, Kumiko Hatakeyama, Koichi Kato, Toshiyuki Kabata, Jun Yura
  • Patent number: 6934484
    Abstract: In a copier which is an image-forming apparatus comprising a photoconductor 1, a developing apparatus 4, transfer apparatus 5 which transfers a toner image formed on the photoconductor 1 to a transfer material by heat and pressure using a transfer roller 52, and a fixing apparatus which fixes the toner image transferred to the transfer material, on the transfer material, a heater 56, temperature detection apparatus 57 and temperature control apparatus are provided which controls the temperature to within a range of from the glass transition temperature (Tg) to the softening temperature (Tm) of the toner, and lower than the fixing temperature of the fixing apparatus 7.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: August 23, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Koji Suzuki, Mitsuo Aoki, Hiroto Higuchi, Shinya Nakayama, Maiko Kondo, Bing Shu, Yasushi Koichi, Tadashi Kasai, Yutaka Takahashi
  • Publication number: 20050169668
    Abstract: A transfer residual toner that has not been electrostatically transferred onto a transfer paper P at a transfer nip and remains on a surface of a photosensitive element is temporarily retained by an elastic blade of a toner retaining unit in a mechanical manner before reaching a latent image forming area. When passing through the latent image forming area, the transfer residual toner is returned onto the surface of the photosensitive member at such a timing that writing is not performed by an exposing unit on the surface of the photosensitive element.
    Type: Application
    Filed: December 22, 2004
    Publication date: August 4, 2005
    Inventors: Yasushi Koichi, Koji Suzuki, Shigekazu Enoki, Osamu Ariizumi, Kumiko Hatakeyama
  • Publication number: 20050141917
    Abstract: An image forming apparatus includes an image carrier, a charging device configured to uniformly charge a surface of the image carrier with a charging member applied with a bias of a first polarity (e.g. a negative polarity) for charging. A latent image forming device forms a latent image on the surface of the image carrier uniformly charged. A developing device develops a latent image by depositing toner grains of the first polarity on the latent image to thereby form a corresponding toner image. A transferring device forms an electric field between the image carrier and a moving member that serves as a movable contact with the image carrier to thereby transfer the toner image from the surface of the image carrier to the moving member or to a recording member nipped between the image carrier and the moving member. A polarity controlling device sets residual toner to a second polarity (e.g.
    Type: Application
    Filed: December 3, 2004
    Publication date: June 30, 2005
    Inventors: Shigekazu Enoki, Koji Suzuki, Yasushi Koichi, Osamu Ariizumi, Kumiko Hatakeyama, Koichi Kato, Masahide Yamashita, Toshiyuki Kabata, Jun Yura
  • Patent number: 6899986
    Abstract: An image forming method, comprising passing a toner image-bearing sheet through a nip defined between two rollers including a heater roller to fix the toner image on the sheet, wherein the toner image is formed from a toner comprising a binder resin, and a colorant, wherein the toner image before the passage through the nip has a toner volume V1 and a toner image area S1, wherein the toner image after the passage through the nip has a toner volume V2 and a toner image area S2, and wherein a volume change Vt and an area change St defined by the formulas shown below are 30% or less and 20% or less, respectively: Vt(%)=(V1?V2)/V1×100 St(%)=(S2?S2)/S1×100. Alternatively, the toner image before the passage through the nip has a surface roughness of 2.5 ?m or less.
    Type: Grant
    Filed: September 23, 2002
    Date of Patent: May 31, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuo Aoki, Kumi Hasegawa, Toshiaki Higaya, Yasushi Koichi, Yutaka Takahashi, Tadashi Kasai