Patents by Inventor Junichiro Otsubo

Junichiro Otsubo 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: 10007199
    Abstract: A single-layer electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The conductive substrate contains aluminum or an aluminum alloy. A surface of the conductive substrate has an aluminum oxide film or an aluminum alloy oxide film. The photosensitive layer is disposed directly on the conductive substrate. The photosensitive layer contains an electron transport material. The electron transport material has a reduction potential of at least ?0.88 V and no greater than ?0.66 V versus a reference electrode (Ag/Ag+). The single-layer electrophotographic photosensitive member has a leakage onset voltage of at least 5.0 kV in a high temperature and humidity environment at a temperature of 30° C. and a relative humidity of 80%. The leakage onset voltage is a voltage applied to the single-layer electrophotographic photosensitive member at which current leakage starts.
    Type: Grant
    Filed: August 26, 2016
    Date of Patent: June 26, 2018
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Tomofumi Shimizu, Junichiro Otsubo, Yasuhiro Oishi
  • Patent number: 9939744
    Abstract: A multi-layer electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer includes a charge generating layer and a charge transport layer. The charge generating layer contains a charge generating material. The charge transport layer contains a charge transport material, a binder resin, and silica particles. The charge transport layer is a monolayer. The charge transport layer is disposed as an outermost surface layer of the multi-layer electrophotographic photosensitive member. The silica particles have a content of at least 0.5 parts by mass and no greater than 15 parts by mass relative to 100 parts by mass of the binder resin. The binder resin includes a polyarylate resin. The polyarylate resin has a repeating unit represented by general formula (I) shown below. In general formula (I), R1-R3 and Y are defined as those described in the specification.
    Type: Grant
    Filed: September 1, 2016
    Date of Patent: April 10, 2018
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Jun Azuma, Kensuke Okawa, Junichiro Otsubo, Akihiko Ogata
  • Publication number: 20170068177
    Abstract: A single-layer electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The conductive substrate contains aluminum or an aluminum alloy. A surface of the conductive substrate has an aluminum oxide film or an aluminum alloy oxide film. The photosensitive layer is disposed directly on the conductive substrate. The photosensitive layer contains an electron transport material. The electron transport material has a reduction potential of at least ?0.88 V and no greater than ?0.66 V versus a reference electrode (Ag/Ag+). The single-layer electrophotographic photosensitive member has a leakage onset voltage of at least 5.0 kV in a high temperature and humidity environment at a temperature of 30° C. and a relative humidity of 80%. The leakage onset voltage is a voltage applied to the single-layer electrophotographic photosensitive member at which current leakage starts.
    Type: Application
    Filed: August 26, 2016
    Publication date: March 9, 2017
    Applicant: KYOCERA Document Solutions Inc.
    Inventors: Tomofumi SHIMIZU, Junichiro OTSUBO, Yasuhiro OISHI
  • Publication number: 20170068178
    Abstract: A multi-layer electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer includes a charge generating layer and a charge transport layer. The charge generating layer contains a charge generating material. The charge transport layer contains a charge transport material, a binder resin, and silica particles. The charge transport layer is a monolayer. The charge transport layer is disposed as an outermost surface layer of the multi-layer electrophotographic photosensitive member. The silica particles have a content of at least 0.5 parts by mass and no greater than 15 parts by mass relative to 100 parts by mass of the binder resin. The binder resin includes a polyarylate resin. The polyarylate resin has a repeating unit represented by general formula (I) shown below. In general formula (I), R1-R3 and Y are defined as those described in the specification.
    Type: Application
    Filed: September 1, 2016
    Publication date: March 9, 2017
    Applicant: KYOCERA Document Solutions Inc.
    Inventors: Jun AZUMA, Kensuke OKAWA, Junichiro OTSUBO, Akihiko OGATA
  • Patent number: 9213229
    Abstract: A positively chargeable electrophotographic photosensitive member has a photosensitive layer. The photosensitive layer at least includes the following layers layered in the stated order: (I) a charge transport layer at least containing a hole transport material and a binder resin; and (II) a charge generating-and-transporting layer at least containing a charge generating material, an electron transport material, a hole transport material, and a binder resin all within this layer. The binder resin contained in the charge transport layer is different from the binder resin contained in the charge generating-and-transporting layer, and either of the binder resins contains a polyvinyl acetal resin.
    Type: Grant
    Filed: January 30, 2014
    Date of Patent: December 15, 2015
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Yuko Iwashita, Yukimasa Watanabe, Junichiro Otsubo, Kazuaki Ezure, Kazutaka Sugimoto
  • Patent number: 9158264
    Abstract: A single-layer-type electrophotographic photosensitive member includes a layer disposed on an electrically conductive substrate, the layer including at least a charge-generating material, an electron transport material, a hole transport material, and a binder resin within the same layer. The charge-generating material contains a phthalocyanine pigment and N-type pigments including at least a perylene-based pigment and an azo-based pigment, and the total amount of the N-type pigments is 0.03 to 10 parts by mass relative to 1 part by mass of the phthalocyanine pigment.
    Type: Grant
    Filed: October 31, 2013
    Date of Patent: October 13, 2015
    Assignee: Kyocera Document Solutions Inc.
    Inventors: Yuko Iwashita, Kazutaka Sugimoto, Junichiro Otsubo, Yukimasa Watanabe, Kazuaki Edure
  • Publication number: 20140212802
    Abstract: A multi-layered electrophotographic photosensitive member includes a multi-layered photosensitive layer. In the multi-layered photosensitive layer, a charge generating layer that contains a charge generating material and a charge transport layer that contains a charge transport material and a binder resin are layered sequentially. The binder resin includes a polycarbonate resin represented by a formula (1).
    Type: Application
    Filed: January 30, 2014
    Publication date: July 31, 2014
    Applicant: KYOCERA DOCUMENT SOLUTIONS INC.
    Inventors: Junichiro OTSUBO, Jun AZUMA, Takayuki INOUE
  • Publication number: 20140212803
    Abstract: A positively chargeable electrophotographic photosensitive member has a photosensitive layer. The photosensitive layer at least includes the following layers layered in the stated order: (I) a charge transport layer at least containing a hole transport material and a binder resin; and (II) a charge generating-and-transporting layer at least containing a charge generating material, an electron transport material, a hole transport material, and a binder resin all within this layer. The binder resin contained in the charge transport layer is different from the binder resin contained in the charge generating-and-transporting layer, and either of the binder resins contains a polyvinyl acetal resin.
    Type: Application
    Filed: January 30, 2014
    Publication date: July 31, 2014
    Applicant: KYOCERA DOCUMENT SOLUTIONS INC.
    Inventors: Yuko IWASHITA, Yukimasa WATANABE, Junichiro OTSUBO, Kazuaki EZURE, Kazutaka SUGIMOTO
  • Patent number: 8765337
    Abstract: The present invention is to provide a multilayer type electrophotographic photoconductor capable of stably obtaining a high image quality image over a long term by restraining the exposure memory and the photo memory, and an image forming apparatus comprising such a multilayer type electrophotographic photoconductor. A multilayer type electrophotographic photoconductor comprising a charge generating layer containing at least a charge generating agent on a base member directly or via an intermediate layer, and a charge transporting layer containing at least a charge transporting agent and a binder resin formed successively, wherein the light absorption degree at a 680 nm wavelength light beam in the photoconductive layer of the multilayer type electrophotographic photoconductor is of a value of 0.8 or less, and the light absorption degree at a 450 nm wavelength light beam is of a value of 1.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: July 1, 2014
    Assignee: Kyocera Mita Corporation
    Inventors: Keiji Maruo, Junichiro Otsubo, Jun Azuma
  • Publication number: 20140120464
    Abstract: A single-layer-type electrophotographic photosensitive member includes a layer disposed on an electrically conductive substrate, the layer including at least a charge-generating material, an electron transport material, a hole transport material, and a binder resin within the same layer. The charge-generating material contains a phthalocyanine pigment and N-type pigments including at least a perylene-based pigment and an azo-based pigment, and the total amount of the N-type pigments is 0.03 to 10 parts by mass relative to 1 part by mass of the phthalocyanine pigment.
    Type: Application
    Filed: October 31, 2013
    Publication date: May 1, 2014
    Applicant: Kyocera Document Solutions Inc.
    Inventors: Yuko Iwashita, Kazutaka Sugimoto, Junichiro Otsubo, Yukimasa Watanabe, Kazuaki Edure
  • Patent number: 8686133
    Abstract: The invention provides an oxo-titanylphthalocyanine crystal which is stable, is superior in dispersibility in a photoreceptive layer and efficiently contributes to improvements in sensitivity and charge retention rate of an electrophotographic photoreceptor when it is used as a charge generating agent, a method for producing the oxo-titanylphthalocyanine crystal, and an electrophotographic photoreceptor.
    Type: Grant
    Filed: July 11, 2012
    Date of Patent: April 1, 2014
    Assignee: Kyocera Document Solutions Inc.
    Inventors: Daisuke Kuboshima, Jun Azuma, Yoshio Inagaki, Junichiro Otsubo, Keiji Maruo
  • Publication number: 20120296082
    Abstract: The invention provides an oxo-titanylphthalocyanine crystal which is stable, is superior in dispersibility in a photoreceptive layer and efficiently contributes to improvements in sensitivity and charge retention rate of an electophotographic photoreceptor when it is used as a charge generating agent, a method for producing the oxo-titanylphthalocyanine crystal, and an electrophotographic photoreceptor the oxo-titanylphthalocyanine crystal has predetermined optical characteristics and thermal properties and is produced by a production method including the following steps (a) to (d): (a) a step of dissolving a crude oxo-titanylphthalocyanine crystal in an acid to obtain an oxo-titanylphthalocyanine solution; (b) a step of adding the oxo-titanylphthalocyanine solution dropwise in a poor solvent to obtain a wet cake; (c) a step of washing the wet cake with an alcohol having 1 to 4 carbon atoms; and (d) a step of stirring the washed wet cake under heating in a nonaqueous solvent to obtain an oxo-titanylphthalocya
    Type: Application
    Filed: July 11, 2012
    Publication date: November 22, 2012
    Inventors: Daisuke KUBOSHIMA, Jun AZUMA, Yoshio INAGAKI, Junichiro OTSUBO, Keiji MARUO
  • Patent number: 8242261
    Abstract: The invention provides an oxo-titanylphthalocyanine crystal which is stable, is superior in dispersibility in a photoreceptive layer and efficiently contributes to improvements in sensitivity and charge retention rate of an electrophotographic photoreceptor when it is used as a charge generating agent, a method for producing the oxo-titanylphthalocyanine crystal, and an electrophotographic photoreceptor.
    Type: Grant
    Filed: October 1, 2010
    Date of Patent: August 14, 2012
    Assignee: Kyocera Mita Corporation
    Inventors: Daisuke Kuboshima, Jun Azuma, Yoshio Inagaki, Junichiro Otsubo, Keiji Maruo
  • Publication number: 20110046392
    Abstract: The invention provides an oxo-titanylphthalocyanine crystal which is stable, is superior in dispersibility in a photoreceptive layer and efficiently contributes to improvements in sensitivity and charge retention rate of an electrophotographic photoreceptor when it is used as a charge generating agent, a method for producing the oxo-titanylphthalocyanine crystal, and an electrophotographic photoreceptor.
    Type: Application
    Filed: October 1, 2010
    Publication date: February 24, 2011
    Inventors: Daisuke Kuboshima, Jun Azuma, Yoshio Inagaki, Junichiro Otsubo, Keiji Maruo
  • Patent number: 7855286
    Abstract: According to the present invention, a titanyl phthalocyanin crystal excellent in storage stability in organic solvents, a method for preparing the same and an electrophotographic photoconductor using the same are provided. In the titanyl phthalocyanin crystal, the method for preparing such a titanyl phthalocyanin crystal and the electrophotographic photoconductor using the same, the titanyl phthalocyanin crystal is characterized by having the maximum peak at a Bragg angle 2?±0.2°=27.2° in a CuK? characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in a differential scanning calorimetric analysis.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: December 21, 2010
    Assignee: Kyocera Mita Corporation
    Inventors: Junichiro Otsubo, Jun Azuma
  • Patent number: 7693454
    Abstract: Disclosed is an image forming apparatus composed of a combination of multi-layered electrophotographic photoreceptor wherein an undercoat layer is made of at least fine titanium oxide particles and a binder resin and has a thickness of 3 ?m or less and the fine titanium oxide particles are surface treated with alumina and silica and have a number average primary particle size of 20 nm or less, and exposing means by LED exposure. Thus, an electrophotographic photoreceptor having good balance between dispersibility of titanium oxide and electrical insulation properties is obtained and image fog does not occur under high temperature and high humidity environment and also excellent image quality can be maintained during continuous printing under low temperature and low humidity environment.
    Type: Grant
    Filed: March 13, 2007
    Date of Patent: April 6, 2010
    Assignee: Kyocera Mita Corporation
    Inventors: Jun Azuma, Junichiro Otsubo
  • Publication number: 20100081073
    Abstract: According to the present invention, a titanyl phthalocyanin crystal excellent in storage stability in organic solvents, a method for preparing the same and an electrophotographic photoconductor using the same are provided. In the titanyl phthalocyanin crystal, the method for preparing such a titanyl phthalocyanin crystal and the electrophotographic photoconductor using the same, the titanyl phthalocyanin crystal is characterized by having the maximum peak at a Bragg angle 2 ?±0.2°=27.2° in a CuK? characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in a differential scanning calorimetric analysis.
    Type: Application
    Filed: October 29, 2009
    Publication date: April 1, 2010
    Inventors: Junichiro Otsubo, Jun Azuma
  • Patent number: 7399564
    Abstract: An electrophotographic photoconductor where generation of cracks, crystallization of a photosensitive layer, and the like occur infrequently by sticking of finger oil. An electrophotographic photoconductor includes a conductive substrate on which a photosensitive layer containing at least a charge generating agent, a hole transfer agent and a binding resin is provided, wherein the binding resin is comprised of a plurality of polycarbonate resins; and the photosensitive layer contains a biphenyl derivative as a plasticizer component represented by the following general formula (1). (wherein R1 to R10 each independently represent a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, and R represents a substituted or unsubstituted aryl group having 1 to 12 carbon atoms or a substituted or unsubstituted alkylene group having 1 to 12 carbon atoms).
    Type: Grant
    Filed: August 29, 2006
    Date of Patent: July 15, 2008
    Assignee: Kyocera Mita Corporation
    Inventors: Jun Azuma, Junichiro Otsubo
  • Publication number: 20080050666
    Abstract: To provide an electrophotographic photoconductor which can effectively prevent the generation of exposure memory and the increase in residual potential by easily adjusting the electroconductivity in an intermediate layer, and an image forming apparatus using the electrophotographic photoconductor. An electrophotographic photoconductor comprising a base body, and an intermediate layer containing a titanium oxide and a binding resin and a photosensitive layer which are arranged on the base body, and an image forming apparatus using the same, wherein an average primary particle diameter of the titanium oxide is set to a value within the range of 5 to 30 nm, a thickness of the intermediate layer set to a value within the range of 0.5 to 3 ?m, and the volume resistivity in the intermediate layer is set to a value within the range of 1×1010 to 5×1013 ?·cm.
    Type: Application
    Filed: August 14, 2007
    Publication date: February 28, 2008
    Inventors: Junichiro Otsubo, Jun Azuma, Keiji Maruo, Yoshio Inagaki
  • Publication number: 20080026310
    Abstract: The invention provides an oxo-titanylphthalocyanine crystal which is stable, is superior in dispersibility in a photoreceptive layer and efficiently contributes to improvements in sensitivity and charge retention rate of an electrophotographic photoreceptor when it is used as a charge generating agent, a method for producing the oxo-titanylphthalocyanine crystal, and an electrophotographic photoreceptor.
    Type: Application
    Filed: July 10, 2007
    Publication date: January 31, 2008
    Inventors: Daisuke Kuboshima, Jun Azuma, Yoshio Inagaki, Junichiro Otsubo, Keiji Maruo