Patents by Inventor Masafumi Ohta

Masafumi Ohta 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: 8767748
    Abstract: A signal distribution circuit includes: first to n-th input lines on which first to n-th signals are respectively input; first to (n?1)th selectors each of which selects one of two inputs under the control of a select signal; and a first output line on which the first signal is output and second to n-th output lines on which output signals of the first to (n?1)th selectors are respectively output, wherein: the first and second inputs of the first selector are supplied with the first signal and the second signal, respectively, the first and second inputs of the i-th selector (i is an integer between 2 and (n?1)) are supplied with the output signal of the (i?1)th selector and the (i+1)th signal, respectively, and any of the selectors, when selected by the select signal, selects the second input and, when not selected by the select signal, selects the first input.
    Type: Grant
    Filed: August 29, 2011
    Date of Patent: July 1, 2014
    Assignee: Fujitsu Limited
    Inventors: Masafumi Ohta, Hiromichi Makishima, Hiroyuki Honma
  • Patent number: 8557489
    Abstract: To provide a gallium phthalocyanine compound, which is expressed by the following general formula (I): where R1 to R32 are each independently a hydrogen atom, an alkoxy group, an alkylthio group, an alkyl group, a halogen atom, a nitro group, or an aryl group.
    Type: Grant
    Filed: December 27, 2010
    Date of Patent: October 15, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiromi Sakaguchi, Masafumi Ohta, Yoshiki Yanagawa
  • Patent number: 8541557
    Abstract: An azo compound having the following formula (I): A(E)n??(I) wherein A represents a residue of an azo compound, bonded with n pieces of E group through one or more heteroatom being N or O and forming a part of the residue A; E independently represents a hydrogen atom or —C(?O)—O—R1 wherein R1 represents a substituted or an unsubstituted alkyl group having 4 to 10 carbon atoms, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group or an aralkyl group; and n represents an integer of from 1 to 10.
    Type: Grant
    Filed: June 15, 2012
    Date of Patent: September 24, 2013
    Assignee: Ricoh Company, Ltd.
    Inventor: Masafumi Ohta
  • Patent number: 8530124
    Abstract: A hydroxygallium phthalocyanine composite pigment, which is a composite pigment wherein an azo compound expressed by the following general formula (a) is conjugated to a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine composite pigment has diffraction peaks at least at 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° on an X-ray diffraction spectrum with Bragg angle of 2?±0.2°, using Cu—K? X-rays: A(H)n??General Formula (a) where A is a residue of an azo compound; H is a hydrogen atom; the residue A is bonded to one or more hydrogen atoms, where the number of the hydrogen atoms is expressed with n, via one or more heteroatoms which are selected from the group consisting of N and O, and form part of the residue A; and n is an integer of 1 to 9.
    Type: Grant
    Filed: December 10, 2010
    Date of Patent: September 10, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiromi Sakaguchi, Masafumi Ohta, Yoshiki Yanagawa
  • Patent number: 8383304
    Abstract: A gallium phthalocyanine compound represented by the following chemical structure I, where X represents a substituted or non-substituted alkyl group, a substituted or non-substituted alkenyl group, a substituted or non-substituted alkynyl group, a substituted or non-substituted aralkyl group, a substituted or non-substituted cycloalkyl group, a substituted or non-substituted aryl group, or a hydrogen atom, where substitution groups thereof are an alkoxy group, an alkylthio group, an alkyl group, a halogen atom, nitro group, amino group, an aryl group, carboxylic group, and cyano group, R1 to R16 independently represent a hydrogen atom, an alkoxy group, an alkylthio group, an alkyl group, a halogen atom, nitro group, or aryl group, n represents an integer of from 1 to 3 but excluding a combination in which n is 1 and X is methyl group.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: February 26, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoshiki Yanagawa, Masafumi Ohta
  • Patent number: 8380109
    Abstract: An image forming apparatus including at least an image bearing member having a substrate having a photosensitive layer thereon, the image bearing member to bear a latent electrostatic image on a surface thereof, a charging device to the surface of the image bearing member, an irradiation device to irradiate the surface of the image bearing member with light to form a latent electrostatic image thereon, a development device to develop the latent electrostatic with toner to obtain a developed image, a transfer device to transfer the developed image to a recording medium, and a cleaning device to clean the surface of the image bearing member, wherein the photosensitive layer includes naphthalene tetracarbonic acid diimide derivative as a charge transport material represented by the following Chemical Structure (1): In the Chemical Structure (1), Z represents a group represented by the following Chemical Formula (1): or the following Chemical Formula (2): —R9??Chemical Formula (2).
    Type: Grant
    Filed: January 9, 2009
    Date of Patent: February 19, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Eiji Kurimoto, Keisuke Shimoyama, Tomoyuki Shimada, Masafumi Ohta, Yuuji Tanaka
  • Publication number: 20120253025
    Abstract: An azo compound having the following formula (I): A(E)n??(I) wherein A represents a residue of an azo compound, bonded with n pieces of E group through one or more heteroatom being N or O and forming a part of the residue A; E independently represents a hydrogen atom or —C(?O)—O—R1 wherein R1 represents a substituted or an unsubstituted alkyl group having 4 to 10 carbon atoms, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group or an aralkyl group; and n represents an integer of from 1 to 10.
    Type: Application
    Filed: June 15, 2012
    Publication date: October 4, 2012
    Applicant: RICOH COMPANY, LTD.
    Inventor: Masafumi OHTA
  • Patent number: 8232376
    Abstract: An azo compound having the following formula (I): A(E)n??(I) wherein A represents a residue of an azo compound, bonded with n pieces of E group through one or more heteroatom being N or O and forming a part of the residue A; E independently represents a hydrogen atom or —C(?O)—O—R1 wherein R1 represents a substituted or an unsubstituted alkyl group having 4 to 10 carbon atoms, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group or an aralkyl group; and n represents an integer of from 1 to 10.
    Type: Grant
    Filed: June 26, 2008
    Date of Patent: July 31, 2012
    Assignee: Ricoh Company, Ltd.
    Inventor: Masafumi Ohta
  • Patent number: 8232031
    Abstract: The present invention provides a naphthalenetetracarboxylic acid diimide derivative represented by the following general formula (1): wherein R1 and R2, which are identical or different, each represent a substituted or non-substituted alkyl group or a substituted or non-substituted aromatic hydrocarbon group; R3 represents an alkyl group having 1 to 8 carbon atoms or an aromatic hydrocarbon group; R4, R5, R6 and R7, which are identical or different, each represent a hydrogen atom, a substituted or non-substituted alkyl group, or a substituted or non-substituted aromatic hydrocarbon group; and R1 and R2 may be linked to form a substituted or non-substituted heterocyclic group including a nitrogen atom; with compounds where all of R1, R2 and R3 are a methyl group, and compounds where both of R1 and R2 are a methyl group and R3 is a 1-octyl group being excluded.
    Type: Grant
    Filed: September 5, 2008
    Date of Patent: July 31, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Masafumi Ohta, Tomoyuki Shimada, Yuuji Tanaka, Eiji Kurimoto, Keisuke Shimoyama
  • Patent number: 8206880
    Abstract: An electrophotographic photoreceptor, including an electroconductive substrate; and a photosensitive layer overlying the substrate, wherein the photosensitive layer comprises a complex azo pigment comprising an azo compound having the following formula (a): A(H)n??(a) wherein A represents a residue of an azo compound, bonded with n pieces of hydrogen atom through one or more heteroatom being N or O and forming a part of the residue A; H represents a hydrogen atom; and n represents an integer of from 1 to 9, and a pigment.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: June 26, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiromi Tada, Masafumi Ohta, Tatsuya Niimi, Norio Nagayama, Yoshiki Yanagawa, Yuuji Tanaka
  • Patent number: 8207312
    Abstract: A method of preparing a complex-azo pigment having plural pigment components including at least an azo pigment represented by the following formula (a) A(H)n??(a) Pigments, both limited and unlimited by the process of making.
    Type: Grant
    Filed: July 7, 2009
    Date of Patent: June 26, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Masafumi Ohta, Hiromi Tada, Yoshiki Yanagawa
  • Publication number: 20120134367
    Abstract: A signal distribution circuit includes: first to n-th input lines on which first to n-th signals are respectively input; first to (n?1)th selectors each of which selects one of two inputs under the control of a select signal; and a first output line on which the first signal is output and second to n-th output lines on which output signals of the first to (n?1)th selectors are respectively output, wherein: the first and second inputs of the first selector are supplied with the first signal and the second signal, respectively, the first and second inputs of the i-th selector (i is an integer between 2 and (n?1)) are supplied with the output signal of the (i?1)th selector and the (i+1)th signal, respectively, and any of the selectors, when selected by the select signal, selects the second input and, when not selected by the select signal, selects the first input.
    Type: Application
    Filed: August 29, 2011
    Publication date: May 31, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Masafumi OHTA, Hiromichi MAKISHIMA, Hiroyuki HONMA
  • Publication number: 20110207043
    Abstract: A gallium phthalocyanine compound represented by the following chemical structure I, where X represents a substituted or non-substituted alkyl group, a substituted or non-substituted alkenyl group, a substituted or non-substituted alkynyl group, a substituted or non-substituted aralkyl group, a substituted or non-substituted cycloalkyl group, a substituted or non-substituted aryl group, or a hydrogen atom, where substitution groups thereof are an alkoxy group, an alkylthio group, an alkyl group, a halogen atom, nitro group, amino group, an aryl group, carboxylic group, and cyano group, R1 to R16 independently represent a hydrogen atom, an alkoxy group, an alkylthio group, an alkyl group, a halogen atom, nitro group, or aryl group, n represents an integer of from 1 to 3 but excluding a combination in which n is 1 and X is methyl group.
    Type: Application
    Filed: February 17, 2011
    Publication date: August 25, 2011
    Inventors: Yoshiki YANAGAWA, Masafumi Ohta
  • Publication number: 20110159418
    Abstract: A hydroxygallium phthalocyanine composite pigment, which is a composite pigment wherein an azo compound expressed by the following general formula (a) is conjugated to a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine composite pigment has diffraction peaks at least at 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° on an X-ray diffraction spectrum with Bragg angle of 2?±0.2°, using Cu—K? X-rays: A(H)n ??General Formula (a) where A is a residue of an azo compound; H is a hydrogen atom; the residue A is bonded to one or more hydrogen atoms, where the number of the hydrogen atoms is expressed with n, via one or more heteroatoms which are selected from the group consisting of N and O, and form part of the residue A; and n is an integer of 1 to 9.
    Type: Application
    Filed: December 10, 2010
    Publication date: June 30, 2011
    Inventors: Hiromi SAKAGUCHI, Masafumi Ohta, Yoshiki Yanagawa
  • Publication number: 20110159420
    Abstract: To provide a gallium phthalocyanine compound, which is expressed by the following general formula (I) where R1 to R32 are each independently a hydrogen atom, an alkoxy group, an alkylthio group, an alkyl group, a halogen atom, a nitro group, or an aryl group.
    Type: Application
    Filed: December 27, 2010
    Publication date: June 30, 2011
    Inventors: Hiromi Sakaguchi, Masafumi Ohta, Yoshiki Yanagawa
  • Patent number: 7858278
    Abstract: An electrophotographic photoreceptor is provided, including an electroconductive substrate and a photosensitive layer located overlying the electroconductive substrate, wherein an outermost layer of the electrophotographic photoreceptor includes a resin including a graft copolymer in which a monomer having a polar group is graft polymerized to a polycarbonate resin, a polyarylate resin, or a copolymer thereof, and a filler; along with an image forming apparatus and a process cartridge using the electrophotographic photoreceptor.
    Type: Grant
    Filed: May 18, 2007
    Date of Patent: December 28, 2010
    Assignee: Ricoh Company Limited
    Inventors: Hiroshi Ikuno, Masafumi Ohta, Tomoyuki Shimada, Yuuji Tanaka, Hongguo Li
  • Publication number: 20100310975
    Abstract: An electrophotographic photoreceptor, including an electroconductive substrate; and a photosensitive layer overlying the substrate, wherein the photosensitive layer comprises a complex azo pigment comprising an azo compound having the following formula (a): A(H)n??(a) wherein A represents a residue of an azo compound, bonded with n pieces of hydrogen atom through one or more heteroatom being N or O and forming a part of the residue A; H represents a hydrogen atom; and n represents an integer of from 1 to 9, and a pigment.
    Type: Application
    Filed: June 2, 2010
    Publication date: December 9, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hiromi Tada, Masafumi Ohta, Tatsuya Niimi, Norio Nagayama, Yoshiki Yanagawa, Yuuji Tanaka
  • Publication number: 20100010204
    Abstract: A method of preparing a complex-azo pigment having plural pigment components including at least an azo pigment represented by the following formula (a) A(H)n ??(a) Pigments, both limited and unlimited by the process of making.
    Type: Application
    Filed: July 7, 2009
    Publication date: January 14, 2010
    Inventors: Masafumi OHTA, Hiromi Tada, Yoshiki Yanagawa
  • Publication number: 20090180804
    Abstract: An image forming apparatus including at least an image bearing member having a substrate having a photosensitive layer thereon, the image bearing member to bear a latent electrostatic image on a surface thereof, a charging device to the surface of the image bearing member, an irradiation device to irradiate the surface of the image bearing member with light to form a latent electrostatic image thereon, a development device to develop the latent electrostatic with toner to obtain a developed image, a transfer device to transfer the developed image to a recording medium, and a cleaning device to clean the surface of the image bearing member, wherein the photosensitive layer includes naphthalene tetracarbonic acid diimide derivative as a charge transport material represented by the following Chemical Structure (1): In the Chemical Structure (1), Z represents a group represented by the following Chemical Formula (1): or the following Chemical Formula (2): —R9 ??Chemical Formula (2).
    Type: Application
    Filed: January 9, 2009
    Publication date: July 16, 2009
    Inventors: Eiji Kurimoto, Keisuke Shimoyama, Tomoyuki Shimada, Masafumi Ohta, Yuuji Tanaka
  • Publication number: 20090068577
    Abstract: The present invention provides a naphthalenetetracarboxylic acid diimide derivative represented by the following general formula (1): wherein R1 and R2, which are identical or different, each represent a substituted or non-substituted alkyl group or a substituted or non-substituted aromatic hydrocarbon group; R3 represents an alkyl group having 1 to 8 carbon atoms or an aromatic hydrocarbon group; R4, R5, R6 and R7, which are identical or different, each represent a hydrogen atom, a substituted or non-substituted alkyl group, or a substituted or non-substituted aromatic hydrocarbon group; and R1 and R2 may be linked to form a substituted or non-substituted heterocyclic group including a nitrogen atom; with compounds where all of R1, R2 and R3 are a methyl group, and compounds where both of R1 and R2 are a methyl group and R3 is a 1-octyl group being excluded.
    Type: Application
    Filed: September 5, 2008
    Publication date: March 12, 2009
    Applicant: RICOH COMPANY, LTD.
    Inventors: Masafumi OHTA, Tomoyuki SHIMADA, Yuuji TANAKA, Eiji KURIMOTO, Keisuke SHIMOYAMA