Patents by Inventor Masahiro Kurachi

Masahiro Kurachi 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: 11971683
    Abstract: Provided an electrophotographic electro-conductive member that can stably suppress an occurrence of fogging in an electrophotographic image. The member comprises a support having an electro-conductive outer surface, and an electro-conductive layer on the outer surface of the support, the electro-conductive layer having a matrix including a cross-linked product of a first rubber, and domains dispersed in the matrix, the domains each includes a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains is exposed to the outer surface of the electro-conductive member to constitute protrusions on an outer surface of the member, the outer surface of the electro-conductive member is constituted by the matrix and the domains exposed to the outer surface of the electrophotographic electro-conductive member, the electrophotographic electro-conductive member has an impedance of 1.0×103? or more and 1.0×108? or less, and some of the domains satisfy two specific requirements.
    Type: Grant
    Filed: September 27, 2021
    Date of Patent: April 30, 2024
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Satoru Nishioka, Kazuhiro Yamauchi, Hiroaki Watanabe, Takumi Furukawa, Yasuhiro Fushimoto, Masahiro Kurachi, Kenji Takashima, Yuichi Kikuchi, Kana Sato
  • Patent number: 11640122
    Abstract: Provided is an electrophotographic electroconductive member including an electroconductive support and an electroconductive layer on the support, an electroconductive member is used, in which an electroconductive layer has a matrix comprising a first rubber, and domains dispersed in the matrix, the domains each comprising a second rubber and an electronic electroconductive agent, and for impedance measured by applying an AC voltage with an amplitude of 1 V to the electroconductive layer while varying frequencies between 1.0×10?2 Hz to 1.0×107 Hz under a specific environment, when a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate is obtained, a slope on a high frequency side is ?0.8 or more and —0.3 or less, and the impedance a low frequency side is from 1.0×103 to 1.0×107?.
    Type: Grant
    Filed: June 8, 2022
    Date of Patent: May 2, 2023
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yuichi Kikuchi, Satoru Nishioka, Kenji Takashima, Kazuhiro Yamauchi, Masahiro Kurachi, Takumi Furukawa, Hiroaki Watanabe, Kenya Terada, Yuya Tomomizu, Toshimitsu Nakazawa
  • Patent number: 11474442
    Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: October 18, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kosuke Fukudome, Tomohiro Unno, Dai Nozaki, Kozue Uratani, Yuta Komiya, Masahiro Kurachi, Kazuhiro Yamauchi, Motonari Ito
  • Publication number: 20220308495
    Abstract: Provided is an electrophotographic electroconductive member including an electroconductive support and an electroconductive layer on the support, an electroconductive member is used, in which an electroconductive layer has a matrix comprising a first rubber, and domains dispersed in the matrix, the domains each comprising a second rubber and an electronic electroconductive agent, and for impedance measured by applying an AC voltage with an amplitude of 1 V to the electroconductive layer while varying frequencies between 1.0×10?2 Hz to 1.0×107 Hz under a specific environment, when a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate is obtained, a slope on a high frequency side is ?0.8 or more and —0.3 or less, and the impedance a low frequency side is from 1.0×103 to 1.0×107?.
    Type: Application
    Filed: June 8, 2022
    Publication date: September 29, 2022
    Inventors: Yuichi Kikuchi, Satoru Nishioka, Kenji Takashima, Kazuhiro Yamauchi, Masahiro Kurachi, Takumi Furukawa, Hiroaki Watanabe, Kenya Terada, Yuya Tomomizu, Toshimitsu Nakazawa
  • Patent number: 11448982
    Abstract: An electrophotographic apparatus including an electrophotographic photosensitive member, a charging unit, and a developing unit, wherein the charging unit includes a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer of the conductive member has a matrix-domain structure, at least some of the domains are exposed at the outer surface of the conductive member, the volume resistivity RI of the matrix is greater than 1.00×1012 ?·cm and not greater than 1.00×1017 ?·cm, the matrix volume resistivity R1 is at least 1.0×105-times the domain volume resistivity R2, and the developing unit includes a toner, the toner includes a binder resin-containing toner particle and an external additive, and the external additive contains fine particles of a hydrotalcite compound.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: September 20, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tsuneyoshi Tominaga, Shohei Tsuda, Shohei Kototani, Noriyoshi Umeda, Masahiro Kurachi, Kazuhiro Yamauchi, Motonari Ito
  • Patent number: 11449000
    Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer at the surface of the conductive member has a matrix-domain structure, at least a portion of the domains is exposed at the outer surface of the conductive member, the outer surface of the conductive member is constituted at least of the matrix and these domains, a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm, a volume resistivity R2 of the domains is less than R1, Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy a prescribed relationship, and an onset temperature T(A) for a storage elastic modulus E? of the toner is not more than 80.0° C.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: September 20, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tomohiro Unno, Kosuke Fukudome, Dai Nozaki, Kozue Uratani, Yuta Komiya, Kazuhiro Yamauchi, Masahiro Kurachi
  • Patent number: 11397388
    Abstract: A process for producing an electrophotographic electroconductive member having an electroconductive support and an electroconductive layer in the order mentioned. The electroconductive layer has a matrix including a crosslinked product of a first rubber, and a domain including a crosslinked product of a second rubber and an electroconductive particle, the process including the steps of: providing a rubber mixture for forming the domain, including carbon black and the second rubber by kneading the carbon black and the second rubber; providing a rubber mixture for forming the matrix, including the first rubber; kneading the rubber mixture for forming the domain and the rubber mixture for forming the matrix to prepare a rubber composition having a matrix-domain structure; forming a layer of the rubber composition on a surface of the electroconductive support; and curing the layer of the rubber composition on the surface of the electroconductive support to form the electroconductive layer.
    Type: Grant
    Filed: October 7, 2021
    Date of Patent: July 26, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Satoru Nishioka, Masahiro Kurachi, Kenji Takashima, Yuichi Kikuchi, Kazuhiro Yamauchi, Kana Sato, Takumi Furukawa, Hiroaki Watanabe, Kenya Terada, Yuya Tomomizu, Toshimitsu Nakazawa
  • Publication number: 20220229379
    Abstract: Used is an electro-conductive member for electrophotography including: a support having an electro-conductive outer surface; and an electro-conductive layer on the outer surface of the support, wherein the electro-conductive layer includes: a matrix containing a first crosslinked rubber product and having a volume resistivity greater than 1.0×1012 ?cm; and domains dispersed in the matrix, wherein the domain includes a second crosslinked rubber product and an electron conductive agent; and the electro-conductive layer includes a region T in which the volume resistivity of the matrix decreases in a depth direction from the outer surface of the electro-conductive member.
    Type: Application
    Filed: April 1, 2022
    Publication date: July 21, 2022
    Inventors: Shota Kaneko, Yuichi Kikuchi, Kenji Takashima, Masahiro Kurachi, Kazuhiro Yamauchi, Satoru Nishioka, Hiroaki Watanabe
  • Patent number: 11385559
    Abstract: Provided is an electrophotographic electroconductive member including an electroconductive support and an electroconductive layer on the support, an electroconductive member is used, in which an electroconductive layer has a matrix comprising a first rubber, and domains dispersed in the matrix, the domains each comprising a second rubber and an electronic electroconductive agent, and for impedance measured by applying an AC voltage with an amplitude of 1 V to the electroconductive layer while varying frequencies between 1.0×10?2 Hz to 1.0×107 Hz under a specific environment, when a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate is obtained, a slope on a high frequency side is ?0.8 or more and ?0.3 or less, and the impedance a low frequency side is from 1.0×103 to 1.0×107?.
    Type: Grant
    Filed: October 16, 2020
    Date of Patent: July 12, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yuichi Kikuchi, Satoru Nishioka, Kenji Takashima, Kazuhiro Yamauchi, Masahiro Kurachi, Takumi Furukawa, Hiroaki Watanabe, Kenya Terada, Yuya Tomomizu, Toshimitsu Nakazawa
  • Patent number: 11360426
    Abstract: An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging device and a developing device, wherein the charging device comprises a conductive member arranged to be capable of contacting the electrophotographic photosensitive member, a conductive layer of the conductive member comprises a matrix domain structure, at least a part of the domains Dt is exposed at the conductive member outer surface, the matrix has a volume resistivity R1 of larger than 1.00×1012 ?·cm, the domains Dt has a volume resistivity of smaller than R1, the developing device comprises the toner, domains Dc formed of the crystalline material exist in a cross section of the toner, distances between adjacent wall surfaces of the domains Dc is from 30 to 1,100 nm, and a weight-average particle diameter D4 of the toner and distances Dms between adjacent wall surfaces between the domains Dt satisfies D4?Dms.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: June 14, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yoshitaka Suzumura, Hiroyuki Tomono, Takuya Mizuguchi, Osamu Matsushita, Shunsuke Matsushita, Masahiro Kurachi, Kazuhiro Yamauchi
  • Patent number: 11360405
    Abstract: An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging device and a developing device, wherein the charging device comprises a conductive member arranged to be capable of contacting the electrophotographic photosensitive member, the conductive layer at the outer surface of the conductive member comprises a matrix and a plurality of domains dispersed in the matrix, at least some of the domains are exposed at the outer surface of the conductive member, the matrix has a volume resistivity R1 of larger than 1.00×1012 ?·cm, the volume resistivity R1 of the matrix is 1.0×105 times or more a volume resistivity R2 of the domains, the developing device comprises the toner comprising a toner particle and a silica fine particle, and a coverage ratio of the toner surface with the silica fine particles is from 62.0% by area to 100.0% by area as determined by X-ray photoelectron spectroscopy.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: June 14, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Hiroyuki Tomono, Yoshitaka Suzumura, Takuya Mizuguchi, Osamu Matsushita, Masahiro Kurachi, Kazuhiro Yamauchi, Issei Imamura
  • Patent number: 11347156
    Abstract: The electro-conductive member has an electro-conductive support, and an electro-conductive layer in this order, the electro-conductive layer including a matrix and domains, the matrix constituted by a first rubber composition containing a cross-linked product of a first rubber, the domains having electro-conductivity, and dispersed in the matrix, each of the domains constituted by a second rubber composition containing a cross-linked product of a second rubber and an electro-conductive particle, the first rubber and the second rubber being diene-based rubbers, the first rubber having at least one monomer unit, the second rubber having at least one monomer unit different from the monomer unit which the first rubber has; a difference of absolute values of SP values between the first rubber and the second rubber is 0.2 (J/cm3)0.5 to 4.0 (J/cm3)0.5; and a tan ?1/tan ?2 is 0.45 to 2.00.
    Type: Grant
    Filed: March 20, 2020
    Date of Patent: May 31, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Masahiro Kurachi, Kazuhiro Yamauchi, Satoru Nishioka, Kenji Takashima, Yuichi Kikuchi
  • Publication number: 20220026825
    Abstract: An electroconductive member for electrophotography has an electroconductive support and an electroconductive layer in the order mentioned. The electroconductive layer has a matrix including a crosslinked product of a first rubber, and a domain including a crosslinked product of a second rubber and an electroconductive particle. The impedance of the outer surface of the electroconductive member is 1.0×103 to 1.0×108?). 80% by number or more of domains observed at each of a total of nine 15-?m square observation regions, which are disposed at any three points in a thickness region from the outer surface to a specific depth on each of cross sections in the thickness direction at three points: the center of the electroconductive layer in the longitudinal direction and points at a specific distance from the both edges of the electroconductive layer toward the center, satisfy specific requirements.
    Type: Application
    Filed: October 7, 2021
    Publication date: January 27, 2022
    Inventors: Satoru Nishioka, Masahiro Kurachi, Kenji Takashima, Yuichi Kikuchi, Kazuhiro Yamauchi, Kana Sato, Takumi Furukawa, Hiroaki Watanabe, Kenya Terada, Yuya Tomomizu, Toshimitsu Nakazawa
  • Publication number: 20220011684
    Abstract: Provided an electrophotographic electro-conductive member that can stably suppress an occurrence of fogging in an electrophotographic image. The member comprises a support having an electro-conductive outer surface, and an electro-conductive layer on the outer surface of the support, the electro-conductive layer having a matrix including a cross-linked product of a first rubber, and domains dispersed in the matrix, the domains each includes a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains is exposed to the outer surface of the electro-conductive member to constitute protrusions on an outer surface of the member, the outer surface of the electro-conductive member is constituted by the matrix and the domains exposed to the outer surface of the electrophotographic electro-conductive member, the electrophotographic electro-conductive member has an impedance of 1.0×103? or more and 1.0×108? or less, and some of the domains satisfy two specific requirements.
    Type: Application
    Filed: September 27, 2021
    Publication date: January 13, 2022
    Inventors: Satoru Nishioka, Kazuhiro Yamauchi, Hiroaki Watanabe, Takumi Furukawa, Yasuhiro Fushimoto, Masahiro Kurachi, Kenji Takashima, Yuichi Kikuchi, Kana Sato
  • Patent number: 11175602
    Abstract: An electroconductive member for electrophotography has an electroconductive support and an electroconductive layer in the order mentioned. The electroconductive layer has a matrix including a crosslinked product of a first rubber, and a domain including a crosslinked product of a second rubber and an electroconductive particle. The impedance of an outer surface of the electroconductive member is 1.0×103 to 1.0×108?. 80% by number or more of domains observed at each of a total of nine 15-?m square observation regions, which are disposed at any three points in a thickness region from the outer surface to a specific depth on each of cross sections in a thickness direction at three points: the center of the electroconductive layer in the longitudinal direction and points at a specific distance from both edges of the electroconductive layer toward the center, satisfy specific requirements.
    Type: Grant
    Filed: October 16, 2020
    Date of Patent: November 16, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Satoru Nishioka, Masahiro Kurachi, Kenji Takashima, Yuichi Kikuchi, Kazuhiro Yamauchi, Kana Sato, Takumi Furukawa, Hiroaki Watanabe, Kenya Terada, Yuya Tomomizu, Toshimitsu Nakazawa
  • Patent number: 11169454
    Abstract: Provided an electrophotographic electro-conductive member that can stably suppress an occurrence of fogging in an electrophotographic image. The member comprises a support having an electro-conductive outer surface, and an electro-conductive layer on the outer surface of the support, the electro-conductive layer having a matrix including a cross-linked product of a first rubber, and domains dispersed in the matrix, the domains each includes a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains is exposed to the outer surface of the electro-conductive member to constitute protrusions on an outer surface of the member, the outer surface of the electro-conductive member is constituted by the matrix and the domains exposed to the outer surface of the electrophotographic electro-conductive member, the electrophotographic electro-conductive member has an impedance of 1.0×103? or more and 1.0×108? or less, and some of the domains satisfy two specific requirements.
    Type: Grant
    Filed: March 24, 2020
    Date of Patent: November 9, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Satoru Nishioka, Kazuhiro Yamauchi, Hiroaki Watanabe, Takumi Furukawa, Yasuhiro Fushimoto, Masahiro Kurachi, Kenji Takashima, Yuichi Kikuchi, Kana Sato
  • Patent number: 11061342
    Abstract: An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging device, and a developing device, wherein the charging device comprises a conductive member arranged to be capable of contacting the electrophotographic photosensitive member, a conductive layer on the conductive member outer surface comprises a matrix and a plurality of domains dispersed in the matrix, at least some of the domains are exposed at the conductive member outer surface, the matrix has a volume resistivity of larger than 1.00×1012 ?·cm and is 1.0×105 times or more one of the domains, the developing device comprises the toner comprising a toner particle, fine particles A and B, the fine particle A has a volume resistivity of 1.0×103 to 1.0×1010 ?·cm, and the fine particle B is silica fine particle and having a volume resistivity of 1.0×1011 to 1.0×1017 ?·cm.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: July 13, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Noriyoshi Umeda, Tsuneyoshi Tominaga, Shohei Tsuda, Shohei Kototani, Masahiro Kurachi, Kazuhiro Yamauchi, Hideo Kihara
  • Publication number: 20210116827
    Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.
    Type: Application
    Filed: October 15, 2020
    Publication date: April 22, 2021
    Inventors: Kosuke Fukudome, Tomohiro Unno, Dai Nozaki, Kozue Uratani, Yuta Komiya, Masahiro Kurachi, Kazuhiro Yamauchi, Motonari Ito
  • Publication number: 20210116859
    Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer at the surface of the conductive member has a matrix-domain structure, at least a portion of the domains is exposed at the outer surface of the conductive member, the outer surface of the conductive member is constituted at least of the matrix and these domains, a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm, a volume resistivity R2 of the domains is less than R1, Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy a prescribed relationship, and an onset temperature T(A) for a storage elastic modulus E? of the toner is not more than 80.0° C.
    Type: Application
    Filed: October 15, 2020
    Publication date: April 22, 2021
    Inventors: Tomohiro Unno, Kosuke Fukudome, Dai Nozaki, Kozue Uratani, Yuta Komiya, Kazuhiro Yamauchi, Masahiro Kurachi
  • Publication number: 20210116860
    Abstract: An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging device and a developing device, wherein the charging device comprises a conductive member arranged to be capable of contacting the electrophotographic photosensitive member, a conductive layer of the conductive member comprises a matrix domain structure, at least a part of the domains Dt is exposed at the conductive member outer surface, the matrix has a volume resistivity R1 of larger than 1.00×1012 ?·cm, the domains Dt has a volume resistivity of smaller than R1, the developing device comprises the toner, domains Dc formed of the crystalline material exist in a cross section of the toner, distances between adjacent wall surfaces of the domains Dc is from 30 to 1,100 nm, and a weight-average particle diameter D4 of the toner and distances Dms between adjacent wall surfaces between the domains Dt satisfies D4?Dms.
    Type: Application
    Filed: October 15, 2020
    Publication date: April 22, 2021
    Inventors: Yoshitaka Suzumura, Hiroyuki Tomono, Takuya Mizuguchi, Osamu Matsushita, Shunsuke Matsushita, Masahiro Kurachi, Kazuhiro Yamauchi