Patents by Inventor Yasufumi Mizuta

Yasufumi Mizuta 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: 9298112
    Abstract: A method of manufacturing a positively-charged single-layer electrophotographic photoreceptor including the steps of: producing a photosensitive layer application liquid containing a good solvent with respect to a binding resin and at least one organic solvent having a boiling point of 70° C. or higher; and forming a photosensitive layer by coating a photosensitive layer support base having a wall thickness of 0.7 mm or less, with the photosensitive layer application liquid and then drying the photosensitive layer application liquid.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: March 29, 2016
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Yasufumi Mizuta, Sakae Saito, Kazunari Hamasaki, Keizo Kimoto, Syoji Itsumi, Hiroshi Takemoto
  • Patent number: 9285692
    Abstract: Disclosed is a positively-charged single-layer electrophotographic photoreceptor in which a photosensitive layer containing at least a binding resin and a charge transporting material is provided on a photosensitive layer support base with a wall thickness of 0.7 mm or less, wherein when the charge transporting material is solely constituted by a hole transporting material, a content of the hole transporting material is 110 parts by mass or less with respect to 100 parts by mass of the binding resin, and when the charge transporting material is constituted by a hole transporting material and an electron transporting material, a content of the hole transporting material is 130 parts by mass or less and a content of the electron transporting material is 5 parts by mass or more with respect to 100 parts by mass of the binding resin.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: March 15, 2016
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Yasufumi Mizuta, Kazunari Hamasaki, Keizo Kimoto
  • Patent number: 9217981
    Abstract: Disclosed is a positively-charged electrophotographic photoreceptor which uses a tubular photosensitive layer support base with a wall thickness of (t), wherein (t) is 0.7 mm or less, a chamfer angle (a) of an end surface of the photosensitive layer support base is 30° or more and 60° or less with respect to a longitudinal tangent of a surface of a tubular photosensitive layer support base, and an outer end surface-tail edge surface width (b) of the tubular photosensitive layer support base is 0.05 mm or more.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: December 22, 2015
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Keizo Kimoto, Sakae Saito, Yasufumi Mizuta, Kazunari Hamasaki, Syoji Itsumi, Hiroshi Takemoto
  • Publication number: 20150160571
    Abstract: A method of manufacturing a positively-charged single-layer electrophotographic photoreceptor including the steps of: producing a photosensitive layer application liquid containing a good solvent with respect to a binding resin and at least one organic solvent having a boiling point of 70° C. or higher; and forming a photosensitive layer by coating a photosensitive layer support base having a wall thickness of 0.7 mm or less, with the photosensitive layer application liquid and then drying the photosensitive layer application liquid.
    Type: Application
    Filed: February 18, 2015
    Publication date: June 11, 2015
    Inventors: Yasufumi Mizuta, Sakae Saito, Kazunari Hamasaki, Keizo Kimoto, Syoji Itsumi, Hiroshi Takemoto
  • Publication number: 20140093816
    Abstract: A method of manufacturing a positively-charged single-layer electrophotographic photoreceptor including the steps of: producing a photosensitive layer application liquid containing a good solvent with respect to a binding resin and at least one organic solvent having a boiling point of 70° C. or higher; and forming a photosensitive layer by coating a photosensitive layer support base having a wall thickness of 0.7 mm or less, with the photosensitive layer application liquid and then drying the photosensitive layer application liquid.
    Type: Application
    Filed: September 25, 2013
    Publication date: April 3, 2014
    Applicant: KYOCERA Document Solutions Inc.
    Inventors: Yasufumi Mizuta, Sakae Saito, Kazunari Hamasaki, Keizo Kimoto, Syoji Itsumi, Hiroshi Takemoto
  • Publication number: 20140093817
    Abstract: Disclosed is a positively-charged single-layer electrophotographic photoreceptor in which a photosensitive layer containing at least a binding resin and a charge transporting material is provided on a photosensitive layer support base with a wall thickness of 0.7 mm or less, wherein when the charge transporting material is solely constituted by a hole transporting material, a content of the hole transporting material is 110 parts by mass or less with respect to 100 parts by mass of the binding resin, and when the charge transporting material is constituted by a hole transporting material and an electron transporting material, a content of the hole transporting material is 130 parts by mass or less and a content of the electron transporting material is 5 parts by mass or more with respect to 100 parts by mass of the binding resin.
    Type: Application
    Filed: September 25, 2013
    Publication date: April 3, 2014
    Applicant: KYOCERA Document Solutions Inc.
    Inventors: Yasufumi Mizuta, Kazunari Hamasaki, Keizo Kimoto
  • Publication number: 20140093280
    Abstract: Disclosed is a positively-charged electrophotographic photoreceptor which uses a tubular photosensitive layer support base with a wall thickness of (t), wherein (t) is 0.7 mm or less, a chamfer angle (a) of an end surface of the photosensitive layer support base is 30° or more and 60° or less with respect to a longitudinal tangent of a surface of a tubular photosensitive layer support base, and an outer end surface-tail edge surface width (b) of the tubular photosensitive layer support base is 0.05 mm or more.
    Type: Application
    Filed: September 25, 2013
    Publication date: April 3, 2014
    Applicant: KYOCERA Document Solutions Inc.
    Inventors: Keizo Kimoto, Sakae Saito, Yasufumi Mizuta, Kazunari Hamasaki, Syoji Itsumi, Hiroshi Takemoto
  • Patent number: 7555241
    Abstract: An image forming apparatus which can exhibit an excellent charge eliminating effect by erasing a transfer memory using a precharging device with optimized conditions even when a positively-charged single-layer-type electrophotographic photoconductor is used as a photoconductor. In the image forming apparatus which sequentially arranges a charging device, a developing device, a transfer device, and a charge eliminating device around a single-layer-type electrophotographic photoconductor, the charging device charges a surface of the single-layer-type electrophotographic photoconductor with a positive polarity, a precharging device having a conductive member is arranged on an upstream side of the charge eliminating device, the conductive member is brought into contact with the electrophotographic photoconductor, and a current density Ib (?A/m2) of the injected current into the photoconductor from the conductive member is set to a value of 700 (?A/m2) or more.
    Type: Grant
    Filed: August 14, 2006
    Date of Patent: June 30, 2009
    Assignee: Kyocera Mita Corporation
    Inventors: Makoto Shishido, Shiho Okawa, Eiichi Miyamoto, Yasufumi Mizuta
  • Publication number: 20070077089
    Abstract: The present invention provides an image forming apparatus which can exhibit an excellent charge eliminating effect by erasing a transfer memory using a precharging means with optimized conditions even when a positively-charged single-layer-type electrophotographic photoconductor is used as a photoconductor. In the image forming apparatus which sequentially arranges a charging means, a developing means, a transfer means, and a charge eliminating means around a single-layer-type electrophotographic photoconductor, the charging means charges a surface of the single-layer-type electrophotographic photoconductor with a positive polarity, a precharging means having a conductive member is arranged on an upstream side of the charge eliminating means, the conductive member is brought into contact with the electrophotographic photoconductor, and a current density Ib(?A/m2) of the injected current into the photoconductor from the conductive member is set to a value of 700(?A/m2) or more.
    Type: Application
    Filed: August 14, 2006
    Publication date: April 5, 2007
    Inventors: Makoto Shishido, Shiho Okawa, Eiichi Miyamoto, Yasufumi Mizuta
  • Patent number: 6174638
    Abstract: Naphthalenetetracarboxylic acid diimide derivatives represented by the general formula (1), wherein m and n are integers inclusive of 0 but not larger than 6, and are different from each other, R1 is a hydrogen atom, an alkyl group, an alkoxyl group or a halogen atom, either one of R2 or R3 is a substituted or unsubstituted aryl group, and the other one is an alkyl group, an alkoxyl group or an amino group, and wherein when R2 or R3 is an alkoxyl group or an amino group, the number n or m of methylene chains to which this group is bonded is not zero. The derivatives exhibit excellent solubility in an organic solvent, excellent compatibility with a resin binder and excellent photosensitivity, and are very useful as an electron-transporting agent for the photosensitive material for electrophotography.
    Type: Grant
    Filed: May 27, 1999
    Date of Patent: January 16, 2001
    Assignee: Kyocera Mita Corporation
    Inventors: Kou Ishigami, Fumio Sugai, Yasufumi Mizuta
  • Patent number: 6127076
    Abstract: Naphthalenetetracarboxylic acid diimide derivatives represented by the following general formula, ##STR1## wherein R is a hydrogen atom, an alkyl group, an alkoxyl group or a halogen atom, R1 and R2 are different from each other and may be a substituted or unsubstituted alkyl group, alkoxyl group or an aryl group, respectively, and R3 is a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxyl group or an aryl group.The derivatives exhibit excellent solubility in an organic solvent, excellent compatibility with a resin binder and excellent photosensitivity, and are very useful as an electron transporting agent for the electrophotosensitive material.
    Type: Grant
    Filed: May 27, 1999
    Date of Patent: October 3, 2000
    Assignee: Kyocera Mita Corporation
    Inventors: Kou Ishigami, Fumio Sugai, Yasufumi Mizuta
  • Patent number: 5994012
    Abstract: The present invention provides a naphthoquinone derivative represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification. An electrophotosensitive material containing this naphthoquinone derivative as an electron transferring material has high sensitivity.
    Type: Grant
    Filed: September 25, 1997
    Date of Patent: November 30, 1999
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Yukimasa Watanabe, Sakae Saito, Hirofumi Kawaguchi, Akiyoshi Urano, Fumio Sugai, Atsushi Fujii, Yasufumi Mizuta, Toshiyuki Fukami, Ichiro Yamazato, Yuji Tanaka, Eiichi Miyamoto, Hideo Nakamori, Mitsuo Ihara
  • Patent number: 5863688
    Abstract: The present invention provides a naphthoquinone derivative represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification. An electrophotosensitive material containing this naphthoquinone derivative as an electron transferring material has high sensitivity.
    Type: Grant
    Filed: September 6, 1996
    Date of Patent: January 26, 1999
    Assignee: Mita Industrial Co., Ltd
    Inventors: Yukimasa Watanabe, Sakae Saito, Hirofumi Kawaguchi, Akiyoshi Urano, Fumio Sugai, Atsushi Fujii, Yasufumi Mizuta, Toshiyuki Fukami, Ichiro Yamazato, Yuji Tanaka, Eiichi Miyamoto, Hideo Nakamori, Mitsuo Ihara
  • Patent number: 5773613
    Abstract: The present invention provides a tryptoanthrinimine derivative represented by the general formula (Y): ##STR1## wherein R.sup.A to R.sup.M are as defined. Such a derivative of the general formula (Y) is superior in electron transferring capability. Accordingly, an electrophotosensitive material comprising a photosensitive layer containing this derivative (Y) is superior in sensitivity.
    Type: Grant
    Filed: November 28, 1995
    Date of Patent: June 30, 1998
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Hirofumi Kawaguchi, Nobuko Akiba, Yukimasa Watanabe, Hiroaki Iwasaki, Yasuyuki Hanatani, Yasufumi Mizuta, Fumio Sugai, Sakae Saito, Syunichi Matsumoto, Toshiyuki Fukami, Ichiro Yamazato, Hisakazu Uegaito, Yuji Tanaka
  • Patent number: 5705694
    Abstract: The present invention provides a novel trinitrofluorenonimine derivative represented by the general formula (1): ##STR1## wherein R.sup.0 is an alkyl group; and R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are the same or different and indicate a hydrogen atom, an alkyl, an alkoxy, an aryl, an aralkyl, a halogen atom or an alkyl halide. This derivative is superior in electron transferring capability and compatibility with binding resin. Accordingly, an electrophotosensitive material comprising this derivative as an electron transferring material is superior in sensitivity.
    Type: Grant
    Filed: November 17, 1995
    Date of Patent: January 6, 1998
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Hirofumi Kawaguchi, Yasufumi Mizuta, Syunichi Matsumoto, Nobuko Akiba, Toshiyuki Fukami, Ichiro Yamazato, Hisakazu Uegaito, Yuji Tanaka
  • Patent number: 5616441
    Abstract: According to the present invention, there is provided a novel tryptoanthorine derivative represented by the formula: ##STR1## wherein R.sup.1a, R.sup.1b, R.sup.1c, R.sup.1d, R.sup.2a, R.sup.2b, R.sup.2c, and R.sup.2d are the same or different and indicate a hydrogen atom, an alkyl group or a halogenated alkyl group; provided that R.sup.1a, R.sup.1b, R.sub.1c and R.sup.1d do not indicate a hydrogen atom, simultaneously. Tryptoanthorine and a derivative thereof are suitably used for an electrophotosensitive material because of their excellent electron transferring capability.
    Type: Grant
    Filed: September 13, 1995
    Date of Patent: April 1, 1997
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Hirofumi Kawaguchi, Yasufumi Mizuta, Syunichi Matsumoto, Nobuko Akiba, Toshiyuki Fukami, Ichiro Yamazato, Hisakazu Uegaito, Yuji Tanaka
  • Patent number: 5550290
    Abstract: The present invention relates to a benzidine derivative represented by the general formula (1): ##STR1## wherein R.sup.1 to R.sup.6, m and n are as defined in the present specification. The benzidine derivative improves durability and heat resistance of a membrane containing the same while maintaining high hole transferring capability. Therefore, an electrophotosensitive material, which comprises a photosensitive layer containing the benzidine derivative, has high sensitivity and is superior in durability and heat resistance.
    Type: Grant
    Filed: September 28, 1994
    Date of Patent: August 27, 1996
    Assignee: Mita Industrial Co. Ltd.
    Inventors: Yasufumi Mizuta, Masashi Tanaka, Nariaki Muto, Toshiyuki Fukami, Hideo Nakamori, Mikio Kakui, Sakae Saito, Hiroshi Shiomi, Keisuke Sumida, Maki Uchida
  • Patent number: 5424157
    Abstract: An electrophotosensitive material containing, as a charge-generating agent, a compound represented by the following general formula (1), ##STR1## wherein Cp is an azo coupling component, Y is a divalent organic group containing at least one aromatic ring or heterocyclic ring, R1 and R8 are alkyl groups or halogen atoms, respectively, and R2 and R4 are alkyl groups, halogen atoms or hydrogen atoms, respectively. The charge-generating agent used here remains chemically stable and exhibits excellent recurring property and charge-forming efficiency.
    Type: Grant
    Filed: December 1, 1993
    Date of Patent: June 13, 1995
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Eiichi Miyamoto, Yasufumi Mizuta
  • Patent number: 5336576
    Abstract: An azo compound represented by the following general formula IA and an electrophotographic photosensitive member comprising a photosensitive layer containing the azo compound: ##STR1## wherein R.sup.1 and R.sup.2 are the same or different from each other and indicate a hydrogen atom, an alkyl group, an alkenyl group, a hydroxyl group, an alkoxy group, a carboxy group, an alkoxy carbonyl group, an acyl group, an aryl group, a halogen group or a cyano group, respectively; R.sup.14 indicates a hydrogen atom, a halogen group, an alkyl group, an alkoxy group, an aryl group, an amine group, a cyano group, a nitro group or a sulfoxide group; and A indicates a coupler residue having an acceptor property.
    Type: Grant
    Filed: November 24, 1992
    Date of Patent: August 9, 1994
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Eiichi Miyamoto, Yasuyuki Hanatani, Hiroaki Iwasaki, Yasufumi Mizuta, Akihiko Kawahara
  • Patent number: 5288576
    Abstract: An azo compound represented by the following general formula IA and an electrophotographic photosensitive member comprising a photosensitive layer containing the azo compound: ##STR1## wherein R.sup.1 and R.sup.2 are the same or different from each other and indicate a hydrogen atom, an alkyl group, an alkenyl group, a hydroxyl group, an alkoxy group, a carboxy group, an alkoxy carbonyl group, an acyl group, an aryl group, a halogen group or a cyano group, respectively; R.sup.14 indicates a hydrogen atom, a halogen group, an alkyl group, an alkoxy group, an aryl group, an amino group, a cyano group, a nitro group or a sulfoxide group; and A indicates a coupler residue having an acceptor property.
    Type: Grant
    Filed: November 24, 1992
    Date of Patent: February 22, 1994
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Eiichi Miyamoto, Yasuyuki Hanatani, Hiroaki Iwasaki, Yasufumi Mizuta, Akihiko Kawahara