Patents by Inventor Akio Tsujita

Akio Tsujita 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: 9116450
    Abstract: A toner including a petroleum wax, wherein the petroleum wax comprises a paraffin wax having a polarity.
    Type: Grant
    Filed: September 20, 2011
    Date of Patent: August 25, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Masato Iio, Kentarou Matsumoto, Shinya Kobayashi, Akio Tsujita, Katsuhiro Shinohara, Tadashi Kasai, Masakazu Terao, Tsuyoshi Asami
  • Patent number: 8630573
    Abstract: An image forming method including forming a toner image on a transfer medium with a toner comprising a wax having a polar group, and applying a varnish to the toner image. The wax may be a plant wax having an ester group, a wax having a polar group derived from a fatty acid, an oxidized wax, or a mixture thereof. The varnish may include a surfactant, such as a polyoxyethylene glycol, and may be photocurable.
    Type: Grant
    Filed: March 8, 2011
    Date of Patent: January 14, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Masato Iio, Tsuyoshi Asami, Kentarou Matsumoto, Shinya Kobayashi, Akio Tsujita, Kathuhiro Shinohara, Tadashi Kasai, Takashi Bisaiji
  • Patent number: 8626040
    Abstract: After at least one toner image is transferred to a medium to which an image is transferred from at least one of a plurality of image forming stations used, at least one toner image is transferred from at least one of the rest of the image forming stations, and this transfer operation is repeated a plurality of times to transfer toner images to the medium to which an image is transferred. In this manner, the toner images on the medium to which an image is transferred are formed using a desired number of color toner including a transparent toner. In addition, the order in which the transparent toner is transferred from the image forming station that is used for the transparent toner and toner other than the transparent toner is transferred from image forming stations in which the transparent toner is not used can be freely or automatically selected.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: January 7, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Tadashi Kasai, Shinya Kobayashi, Akio Tsujita, Masato Iio, Katsuhiro Shinohara, Masakazu Terao
  • Patent number: 8520261
    Abstract: An image glossiness controller has a main component color specifying unit that identifies a prescribed component color and output identification information thereof. A change in amplitude of a convexoconcavity of a toner layer of the prescribed component color is greatest among those of the other component colors when each of the component color toner is formed and fixed alone. Three or more halftone dot signal generators convert clear toner image information into three or more binary clear toner image signals corresponding to three or more component colors per component color pixel using multiple halftone dot characteristics, respectively. Each of the multiple halftone dot characteristics generating three or more binary clear toner image signals has a reversed phase from that generating three or more binary component color image signals.
    Type: Grant
    Filed: October 27, 2011
    Date of Patent: August 27, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinya Kobayashi, Kentarou Matsumoto, Akio Tsujita, Masato Iio, Tadashi Kasai, Katsuhiro Shinohara, Masakazu Terao, Yoshihiro Sonohara
  • Patent number: 8494385
    Abstract: An image forming apparatus including a color toner image forming unit that forms a color toner image on a recording medium; a first colorless transparent toner image forming unit that forms a first colorless transparent toner image on the color toner image; a first fixing unit that fixes the image on the recording medium; a gloss level increasing device that increases a gloss level of the entire image on the recording medium that has been fixed; a second colorless transparent toner image forming unit that forms a second colorless transparent toner image on the image whose gloss level has been increased; and a second fixing unit that fixes the second colorless transparent toner image on the recording medium.
    Type: Grant
    Filed: February 1, 2011
    Date of Patent: July 23, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Masakazu Terao, Kentarou Matsumoto, Shinya Kobayashi, Akio Tsujita, Masato Lio, Katsuhiro Shinohara, Tadashi Kasai
  • Publication number: 20120105915
    Abstract: An image glossiness controller has a main component color specifying unit that identifies a prescribed component color and output identification information thereof. A change in amplitude of a convexoconcavity of a toner layer of the prescribed component color is greatest among those of the other component colors when each of the component color toner is formed and fixed alone. Three or more halftone dot signal generators convert clear toner image information into three or more binary clear toner image signals corresponding to three or more component colors per component color pixel using multiple halftone dot characteristics, respectively. Each of the multiple halftone dot characteristics generating three or more binary clear toner image signals has a reversed phase from that generating three or more binary component color image signals.
    Type: Application
    Filed: October 27, 2011
    Publication date: May 3, 2012
    Inventors: Shinya KOBAYASHI, Kentarou Matsumoto, Akio Tsujita, Masato Ilo, Tadashi Kasai, Katsuhiro Shinohara, Masakazu Terao, Yoshihiro Sonohara
  • Publication number: 20120082829
    Abstract: A toner including a petroleum wax, wherein the petroleum wax comprises a paraffin wax having a polarity.
    Type: Application
    Filed: September 20, 2011
    Publication date: April 5, 2012
    Inventors: Masato Iio, Kentarou Matsumoto, Shinya Kobayashi, Akio Tsujita, Katsuhiro Shinohara, Tadashi Kasai, Masakazu Terao, Tsuyoshi Asami
  • Publication number: 20120063819
    Abstract: After at least one toner image is transferred to a medium to which an image is transferred from at least one of a plurality of image forming stations used, at least one toner image is transferred from at least one of the rest of the image forming stations, and this transfer operation is repeated a plurality of times to transfer toner images to the medium to which an image is transferred. In this manner, the toner images on the medium to which an image is transferred are formed using a desired number of color toner including a transparent toner. In addition, the order in which the transparent toner is transferred from the image forming station that is used for the transparent toner and toner other than the transparent toner is transferred from image forming stations in which the transparent toner is not used can be freely or automatically selected.
    Type: Application
    Filed: September 13, 2011
    Publication date: March 15, 2012
    Inventors: Tadashi Kasai, Shinya Kobayashi, Akio Tsujita, Masato Ilo, Katsuhiro Shinohara, Masakazu Terao
  • Patent number: 8086148
    Abstract: An electrophotographic image forming apparatus is disclosed. The electrophotographic image forming apparatus includes a photoconductor body, a donor roller which develops an electrostatic latent image on the surface of the photoconductor body by using charged toners, and a development nip section formed between the photoconductor body and the donor roller by having a predetermined gap between the photoconductor body and the donor roller. A developing traveling-wave electrode for generating a traveling-wave electric field is disposed at a position facing the surface of the donor roller at an upstream side of the moving direction of the photoconductor body relative to the development nip section, and a removing traveling-wave electrode for generating a traveling-wave electric field is disposed at a position facing the surface of the donor roller at a downstream side of the moving direction of the photoconductor body relative to the development nip section.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: December 27, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Kaoru Kataoka, Akio Tsujita, Katsuhiko Suzuki
  • Publication number: 20110223527
    Abstract: An image forming method including forming a toner image on a transfer medium with a toner comprising a wax having a polar group, and applying a varnish to the toner image. The wax may be a plant wax having an ester group, a wax having a polar group derived from a fatty acid, an oxidized wax, or a mixture thereof. The varnish may include a surfactant, such as a polyoxyethylene glycol, and may be photocurable.
    Type: Application
    Filed: March 8, 2011
    Publication date: September 15, 2011
    Applicant: Ricoh Company, Ltd.
    Inventors: Masato Iio, Tsuyoshi Asami, Kentarou Matsumoto, Shinya Kobayashi, Akio Tsujita, Kathuhiro Shinohara, Tadashi Kasai, Takashi Bisaiji
  • Publication number: 20110206429
    Abstract: An image forming apparatus including a color toner image forming unit that forms a color toner image on a recording medium; a first colorless transparent toner image forming unit that forms a first colorless transparent toner image on the color toner image; a first fixing unit that fixes the image on the recording medium; a gloss level increasing device that increases a gloss level of the entire image on the recording medium that has been fixed; a second colorless transparent toner image forming unit that forms a second colorless transparent toner image on the image whose gloss level has been increased; and a second fixing unit that fixes the second colorless transparent toner image on the recording medium.
    Type: Application
    Filed: February 1, 2011
    Publication date: August 25, 2011
    Applicant: Ricoh Company, Ltd.
    Inventors: Masakazu Terao, Kentarou Matsumoto, Shinya Kobayashi, Akio Tsujita, Masato Iio, Katsuhiro Shinohara, Tadashi Kasai
  • Publication number: 20090214270
    Abstract: An electrophotographic image forming apparatus is disclosed. The electrophotographic image forming apparatus includes a photoconductor body, a donor roller which develops an electrostatic latent image on the surface of the photoconductor body by using charged toners, and a development nip section formed between the photoconductor body and the donor roller by having a predetermined gap between the photoconductor body and the donor roller. A developing traveling-wave electrode for generating a traveling-wave electric field is disposed at a position facing the surface of the donor roller at an upstream side of the moving direction of the photoconductor body relative to the development nip section, and a removing traveling-wave electrode for generating a traveling-wave electric field is disposed at a position facing the surface of the donor roller at a downstream side of the moving direction of the photoconductor body relative to the development nip section.
    Type: Application
    Filed: February 24, 2009
    Publication date: August 27, 2009
    Inventors: Kaoru KATAOKA, Akio Tsujita, Katsuhiko Suzuki
  • Patent number: 7574164
    Abstract: An electrophotographic apparatus includes: a photoconductor; and two developing rollers facing the photoconductor. A developer fed out from between the two developing rollers is supplied to the photoconductor by the two developing rollers to form a toner image on the photoconductor. The developer includes a carrier having a volume-average particle size smaller than 70 ?m and a volume resistivity not lower than 106 ?·cm. A volume ratio of the carrier in a facing portion between the photoconductor and the developing rollers is not lower than 30% and not higher than 46%.
    Type: Grant
    Filed: September 23, 2005
    Date of Patent: August 11, 2009
    Assignee: Ricoh Company Ltd.
    Inventors: Hisao Okada, Hiroyuki Mabuchi, Teruaki Mitsuya, Tsuneaki Kawanishi, Akio Tsujita
  • Patent number: 7466946
    Abstract: A developing unit includes a plurality of developing rolls over which a developer is conveyed and supplied onto an image carrier which is rotatably supported; and at least one pair of the developing rolls being adjacent to each other. In the pair of the developing rolls, one developing roll rotates in a direction opposite to a rotary direction of the image carrier, and the other developing roll rotates in the same direction of the rotary direction of the image carrier. A regulation member is interposed between the pair of the developing rolls. The regulation member regulates a conveyed amount of the developer. The regulation member is disposed to be opposed to a magnet which is provided within the two adjacent developing rolls. A polarity of the magnet in the pair of developing rolls opposed to each other is different from each other.
    Type: Grant
    Filed: February 7, 2006
    Date of Patent: December 16, 2008
    Assignee: Ricoh Printing Systems, Ltd.
    Inventors: Akio Tsujita, Kaoru Kataoka, Tatsuya Kubo
  • Patent number: 7421222
    Abstract: In a charging device having saw-tooth electrodes for generating corona discharges, an amount of dust, toner, or paper dust attached to the tip end portions of saw-tooth electrodes is reduced. First to third pairs of saw-tooth electrode plates are disposed in a side-by-side fashion along the periphery of a photosensitive drum in which the first pair is disposed at an upstream side with respect to a direction in which the photosensitive drum rotates, the third pair at a downstream side, and the second pair at a central portion between the remaining two. A current flowing per a unit length of the second pair is set to 1.3 to 3 times as much as a current flowing per a unit length of each of the first and third pairs. The currents flowing per a unit length of the first and third pairs are set to be equal to each other.
    Type: Grant
    Filed: January 21, 2005
    Date of Patent: September 2, 2008
    Assignee: Ricoh Printing Systems, Ltd.
    Inventors: Tatsuya Kubo, Akio Tsujita, Yukio Otome
  • Publication number: 20070172262
    Abstract: An electrophotographic apparatus includes: a photoconductor; and two developing rollers facing the photoconductor. A developer fed out from between the two developing rollers is supplied to the photoconductor by the two developing rollers to form a toner image on the photoconductor. The developer includes a carrier having a volume-average particle size smaller than 70 ?m and a volume resistivity not lower than 106 ?·cm. A volume ratio of the carrier in a facing portion between the photoconductor and the developing rollers is not lower than 30% and not higher than 46%.
    Type: Application
    Filed: September 23, 2005
    Publication date: July 26, 2007
    Applicant: Ricoh Printing Systems, Ltd.
    Inventors: Hisao Okada, Hiroyuki Mabuchi, Teruaki Mitsuya, Tsuneaki Kawanishi, Akio Tsujita
  • Publication number: 20060216069
    Abstract: A developing unit includes a plurality of developing rolls over which a developer is conveyed and supplied onto an image carrier which is rotatably supported; and at least one pair of the developing rolls being adjacent to each other. In the pair of the developing rolls, one developing roll rotates in a direction opposite to a rotary direction of the image carrier, and the other developing roll rotates in the same direction of the rotary direction of the image carrier. A regulation member is interposed between the pair of the developing rolls. The regulation member regulates a conveyed amount of the developer. The regulation member is disposed to be opposed to a magnet which is provided within the two adjacent developing rolls. A polarity of the magnet in the pair of developing rolls opposed to each other is different from each other.
    Type: Application
    Filed: February 7, 2006
    Publication date: September 28, 2006
    Applicant: RICOH PRINTING SYSTEMS, LTD.
    Inventors: Akio Tsujita, Kaoru Kataoka, Tatsuya Kubo
  • Publication number: 20050162136
    Abstract: In a charging device having saw-tooth electrodes for generating corona discharges, an amount of dust, toner, or paper dust attached to the tip end portions of saw-tooth electrodes is reduced. First to third pairs of saw-tooth electrode plates are disposed in a side-by-side fashion along the periphery of a photosensitive drum in which the first pair is disposed at an upstream side with respect to a direction in which the photosensitive drum rotates, the third pair at a downstream side, and the second pair at a central portion between the remaining two. A current flowing per a unit length of the second pair is set to 1.3 to 3 times as much as a current flowing per a unit length of each of the first and third pairs. The currents flowing per a unit length of the first and third pairs are set to be equal to each other.
    Type: Application
    Filed: January 21, 2005
    Publication date: July 28, 2005
    Inventors: Tatsuya Kubo, Akio Tsujita, Yukio Otome
  • Publication number: 20050053396
    Abstract: In a scorotron type charging device including a shield case having an opening portion toward a photosensitive body, sawtooth electrodes for generating a corona discharge, and a grid having plural grid wires provided at a predetermined interval from sawtooth electrodes, at least one side surface of shield case is arranged adjacent to one sawtooth electrode, and a relationship between a current It supplied to sawtooth electrodes and current Is flowing through shield case is set to satisfy a conditional expression of ¼?Is/It?½, and an interval between vertexes of sawteeth of the sawtooth electrodes is set to 1 mm or more but 3 mm or less and a relationship between a charged potential Vo of the photosensitive body and a voltage Vg applied to grid is set to satisfy a conditional expression of ?50 V?|Vo|?|Vg|?50 (V).
    Type: Application
    Filed: August 17, 2004
    Publication date: March 10, 2005
    Applicant: Hitachi Printing Solutions, Ltd.
    Inventors: Tatsuya Kubo, Hiroyuki Mabuchi, Akio Tsujita
  • Patent number: 6330403
    Abstract: An image forming apparatus has an image retaining body which is supported so as to be able to move endlessly, a transfer means which is installed at a specific distance away from the surface of the image retaining body or in contact with the surface of the image retaining body, and a paper guide which is installed upstream and downstream, of or at least upstream or downstream the transfer means along the moving direction of the image retaining body for guiding a sheet of paper between the image retaining body and the transfer means and for pressing the paper onto the surface of the image retaining body. The image forming apparatus is equipped with an adjusting means for adjusting the distance between the paper guide means and the transfer means along the moving direction of the image retaining body, thereby varying the length of the paper wound onto the image retaining body.
    Type: Grant
    Filed: August 14, 2000
    Date of Patent: December 11, 2001
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Akio Tsujita, Takashi Rokutanda, Takao Umeda