Patents by Inventor Kumiko Takizawa

Kumiko Takizawa 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: 11112706
    Abstract: Provided is an electrophotographic photosensitive member in which the generation of a positive ghost image is suppressed under a low-temperature and low-humidity environment, and the occurrence of cracking is suppressed under a high-temperature and high-humidity environment. Also provided are a process cartridge mounted with the electrophotographic photosensitive member, and an electrophotographic apparatus including the process cartridge. The electrophotographic photosensitive member of the present disclosure is characterized in that an undercoat layer contains aluminum oxide particles and titanium oxide particles at a specific mass ratio.
    Type: Grant
    Filed: March 27, 2020
    Date of Patent: September 7, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Eileen Takeuchi, Kumiko Takizawa, Ikuyo Kuroiwa, Tsuyoshi Shimada, Wataru Kitamura
  • Patent number: 10935898
    Abstract: An electrophotographic photosensitive member includes a support, an undercoat layer, a photosensitive layer, and a surface layer, the undercoat layer containing a binder resin and strontium titanate particles, the surface layer being a cured film of a composition containing at least one compound selected from a guanamine compound and a melamine compound, and a charge transport material having at least one substituent selected from —OH, —OCH3, —NH2, —SH, and —COOH.
    Type: Grant
    Filed: October 17, 2019
    Date of Patent: March 2, 2021
    Assignee: Canon Kabushiki Kaisha
    Inventors: Ikuyo Kuroiwa, Kumiko Takizawa, Tsuyoshi Shimada, Kan Tanabe, Haruhiko Mitsuda, Takanori Ueno, Tatsuya Ikezue, Wataru Kitamura
  • Patent number: 10921723
    Abstract: Provided is an electrophotographic photosensitive member that can achieve both of abrasion resistance and the suppression of a ghost. The electrophotographic photosensitive member includes: a support; an undercoat layer; a charge-generating layer; and a charge-transporting layer, the undercoat layer, the charge-generating layer, and the charge-transporting layer being arranged in the stated order on the support, wherein the charge-transporting layer includes a charge-transporting substance, and a polymer containing a structure represented by the following general formula (1) and a structure represented by the following general formula (2), wherein the charge-generating layer includes a phthalocyanine crystal and a binder resin, and wherein the undercoat layer includes strontium titanate particles and a binder resin.
    Type: Grant
    Filed: October 9, 2019
    Date of Patent: February 16, 2021
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kumiko Takizawa, Tsuyoshi Shimada, Takanori Ueno, Ikuyo Kuroiwa, Haruhiko Mitsuda, Kan Tanabe, Tatsuya Ikezue
  • Patent number: 10908521
    Abstract: An electrophotographic photoconductor includes, in sequence, a support member; an undercoating layer containing a binder resin and an inorganic particle; and a photosensitive layer, wherein the binder resin of the undercoating layer is an alkyd-melamine resin, and the inorganic particle of the undercoating layer contains a strontium titanate particle.
    Type: Grant
    Filed: October 22, 2019
    Date of Patent: February 2, 2021
    Assignee: Canon Kabushiki Kaisha
    Inventors: Haruhiko Mitsuda, Tatsuya Ikezue, Kumiko Takizawa, Kan Tanabe, Ikuyo Kuroiwa, Takanori Ueno, Tsuyoshi Shimada
  • Patent number: 10838314
    Abstract: The electrophotographic photosensitive member includes an undercoat layer and a surface layer on or above a support in this order, in which the undercoat layer contains metal oxide particles and a specific binder resin, the surface layer contains a charge transporting substance, fluororesin particles, and a specific binder resin, an arithmetic average roughness Ra of a surface of the undercoat layer is 0.15 ?m or less, a refractive index (a) of the metal oxide particles and a refractive index (b) of the binder resin contained in the undercoat layer satisfy a specific relationship, and a refractive index (c) of the binder resin contained in the surface layer and a refractive index (d) of the fluororesin particles satisfy a specific relationship.
    Type: Grant
    Filed: October 16, 2019
    Date of Patent: November 17, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tatsuya Ikezue, Kumiko Takizawa, Ikuyo Kuroiwa, Kan Tanabe, Tsuyoshi Shimada, Haruhiko Mitsuda, Takanori Ueno
  • Publication number: 20200225595
    Abstract: Provided is an electrophotographic photosensitive member in which the generation of a positive ghost image is suppressed under a low-temperature and low-humidity environment, and the occurrence of cracking is suppressed under a high-temperature and high-humidity environment. Also provided are a process cartridge mounted with the electrophotographic photosensitive member, and an electrophotographic apparatus including the process cartridge. The electrophotographic photosensitive member of the present disclosure is characterized in that an undercoat layer contains aluminum oxide particles and titanium oxide particles at a specific mass ratio.
    Type: Application
    Filed: March 27, 2020
    Publication date: July 16, 2020
    Inventors: Eileen Takeuchi, Kumiko Takizawa, Ikuyo Kuroiwa, Tsuyoshi Shimada, Wataru Kitamura
  • Patent number: 10705440
    Abstract: Provided is an electrophotographic photosensitive member that can suppress the generation of both an interference fringe and a streaky uneven part in a circumferential direction on an image. The generation of the interference fringe and the generation of the streaky uneven part in the circumferential direction on the image are suppressed by defining a length of a line-shaped groove of a support in a circumferential direction, and defining roughness parameters of a support in an axial direction.
    Type: Grant
    Filed: May 30, 2019
    Date of Patent: July 7, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Takanori Ueno, Kumiko Takizawa, Ikuyo Kuroiwa, Tsuyoshi Shimada, Wataru Kitamura, Eileen Takeuchi
  • Publication number: 20200133146
    Abstract: Provided are an electrophotographic photosensitive member excellent in suppression of the occurrence of a photomemory, and a process cartridge and an electrophotographic apparatus each including the electrophotographic photosensitive member. The electrophotographic photosensitive member includes in this order: an electroconductive support; an undercoat layer; and a photosensitive layer, wherein the undercoat layer contains strontium titanate particles and a binder resin, and the photosensitive layer contains a butanediol adduct of titanyl phthalocyanine.
    Type: Application
    Filed: October 15, 2019
    Publication date: April 30, 2020
    Inventors: Tsuyoshi Shimada, Kumiko Takizawa, Ikuyo Kuroiwa, Kan Tanabe, Haruhiko Mitsuda, Tatsuya Ikezue, Takanori Ueno
  • Publication number: 20200133148
    Abstract: The electrophotographic photosensitive member includes an undercoat layer and a surface layer on or above a support in this order, in which the undercoat layer contains metal oxide particles and a specific binder resin, the surface layer contains a charge transporting substance, fluororesin particles, and a specific binder resin, an arithmetic average roughness Ra of a surface of the undercoat layer is 0.15 ?m or less, a refractive index (a) of the metal oxide particles and a refractive index (b) of the binder resin contained in the undercoat layer satisfy a specific relationship, and a refractive index (c) of the binder resin contained in the surface layer and a refractive index (d) of the fluororesin particles satisfy a specific relationship.
    Type: Application
    Filed: October 16, 2019
    Publication date: April 30, 2020
    Inventors: Tatsuya Ikezue, Kumiko Takizawa, Ikuyo Kuroiwa, Kan Tanabe, Tsuyoshi Shimada, Haruhiko Mitsuda, Takanori Ueno
  • Publication number: 20200133149
    Abstract: The present disclosure provides an electrophotographic photosensitive member that can suppress a black spot and an exposure memory. The electrophotographic photosensitive member has a support, an undercoat layer and a photosensitive layer having a mono-layer structure in this order, wherein the undercoat layer contains a binder resin and strontium titanate particles; and the photosensitive layer having a mono-layer structure contains a binder resin, a charge generation material, a hole transport material and an electron transport material.
    Type: Application
    Filed: October 21, 2019
    Publication date: April 30, 2020
    Inventors: Takanori Ueno, Kumiko Takizawa, Kan Tanabe, Haruhiko Mitsuda, Ikuyo Kuroiwa, Tsuyoshi Shimada, Wataru Kitamura, Shinji Takagi, Tatsuya Ikezue
  • Publication number: 20200133147
    Abstract: Provided is an electrophotographic photosensitive member that can achieve both of abrasion resistance and the suppression of a ghost. The electrophotographic photosensitive member includes: a support; an undercoat layer; a charge-generating layer; and a charge-transporting layer, the undercoat layer, the charge-generating layer, and the charge-transporting layer being arranged in the stated order on the support, wherein the charge-transporting layer includes a charge-transporting substance, and a polymer containing a structure represented by the following general formula (1) and a structure represented by the following general formula (2), wherein the charge-generating layer includes a phthalocyanine crystal and a binder resin, and wherein the undercoat layer includes strontium titanate particles and a binder resin.
    Type: Application
    Filed: October 9, 2019
    Publication date: April 30, 2020
    Inventors: Kumiko Takizawa, Tsuyoshi Shimada, Takanori Ueno, Ikuyo Kuroiwa, Haruhiko Mitsuda, Kan Tanabe, Tatsuya Ikezue
  • Publication number: 20200133150
    Abstract: An electrophotographic photoconductor includes, in sequence, a support member; an undercoating layer containing a binder resin and an inorganic particle; and a photosensitive layer, wherein the binder resin of the undercoating layer is an alkyd-melamine resin, and the inorganic particle of the undercoating layer contains a strontium titanate particle.
    Type: Application
    Filed: October 22, 2019
    Publication date: April 30, 2020
    Inventors: Haruhiko Mitsuda, Tatsuya Ikezue, Kumiko Takizawa, Kan Tanabe, Ikuyo Kuroiwa, Takanori Ueno, Tsuyoshi Shimada
  • Publication number: 20200133145
    Abstract: An electrophotographic photoconductor includes, in sequence, a support, an undercoat layer, a charge generation layer containing a charge generation material and a first binder resin, and a charge transport layer containing a charge transport material and a second binder resin. The charge generation material in the charge generation layer is chlorogallium phthalocyanine having diffraction peaks at Bragg angles (2?±0.2°) of 7.4°, 16.6°, 25.5°, and 28.3° in an X-ray diffraction pattern obtained by using Cu K-? radiation. The undercoat layer contains strontium titanate particles and a third binder resin.
    Type: Application
    Filed: October 18, 2019
    Publication date: April 30, 2020
    Inventors: Kan Tanabe, Tatsuya Ikezue, Kumiko Takizawa, Haruhiko Mitsuda, Ikuyo Kuroiwa, Takanori Ueno, Tsuyoshi Shimada
  • Publication number: 20200124996
    Abstract: An electrophotographic photosensitive member includes a support, an undercoat layer, a photosensitive layer, and a surface layer, the undercoat layer containing a binder resin and strontium titanate particles, the surface layer being a cured film of a composition containing at least one compound selected from a guanamine compound and a melamine compound, and a charge transport material having at least one substituent selected from —OH, —OCH3, —NH2, —SH, and —COOH.
    Type: Application
    Filed: October 17, 2019
    Publication date: April 23, 2020
    Inventors: Ikuyo Kuroiwa, Kumiko Takizawa, Tsuyoshi Shimada, Kan Tanabe, Haruhiko Mitsuda, Takanori Ueno, Tatsuya Ikezue, Wataru Kitamura
  • Publication number: 20190369513
    Abstract: Provided is an electrophotographic photosensitive member that can suppress the generation of both an interference fringe and a streaky uneven part in a circumferential direction on an image. The generation of the interference fringe and the generation of the streaky uneven part in the circumferential direction on the image are suppressed by defining a length of a line-shaped groove of a support in a circumferential direction, and defining roughness parameters of a support in an axial direction.
    Type: Application
    Filed: May 30, 2019
    Publication date: December 5, 2019
    Inventors: Takanori Ueno, Kumiko Takizawa, Ikuyo Kuroiwa, Tsuyoshi Shimada, Wataru Kitamura, Eileen Takeuchi
  • Patent number: 10488770
    Abstract: There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus in which residual potential is suppressed and a ghost image is prevented from being generated in a low-humidity environment in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member including: an undercoat layer containing a strontium titanate particle having a maximum peak at a position of 2?=32.20±0.20 (? represents a Bragg angle) in a CuK? characteristic X-ray diffraction pattern and a half-value width of the maximum peak of 0.10 deg or more and 0.50 deg or less, and a titanium oxide particle; and a photosensitive layer containing a polyvinyl butyral resin, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.
    Type: Grant
    Filed: September 19, 2018
    Date of Patent: November 26, 2019
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Ikuyo Kuroiwa, Wataru Kitamura, Kumiko Takizawa, Tsuyoshi Shimada, Eileen Takeuchi
  • Patent number: 10353340
    Abstract: There is provided an electrophotographic photosensitive member in which the variation in potential during repeated use is reduced. The electrophotographic photosensitive member is the electrophotographic photosensitive member of which an undercoat layer comprises a urethane resin and titanium oxide particles whose primary particle and secondary particle diameters are defined.
    Type: Grant
    Filed: April 5, 2018
    Date of Patent: July 16, 2019
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Ikuyo Kuroiwa, Kumiko Takizawa, Tsuyoshi Shimada, Eileen Takeuchi, Wataru Kitamura
  • Publication number: 20190094735
    Abstract: There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus in which residual potential is suppressed and a ghost image is prevented from being generated in a low-humidity environment in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member including: an undercoat layer containing a strontium titanate particle having a maximum peak at a position of 2?=32.20±0.20 (? represents a Bragg angle) in a CuK? characteristic X-ray diffraction pattern and a half-value width of the maximum peak of 0.10 deg or more and 0.50 deg or less, and a titanium oxide particle; and a photosensitive layer containing a polyvinyl butyral resin, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.
    Type: Application
    Filed: September 19, 2018
    Publication date: March 28, 2019
    Inventors: Ikuyo Kuroiwa, Wataru Kitamura, Kumiko Takizawa, Tsuyoshi Shimada, Eileen Takeuchi
  • Patent number: 10241429
    Abstract: There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus that are excellent in charging properties and can suppress residual potential in the case where a strontium titanate particle is used as a metal oxide particle in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member in which an undercoat layer contains a strontium titanate particle having a maximum peak at a position of 2?=32.20±0.20 (? represents a Bragg angle) in a CuK? characteristic X-ray diffraction pattern, the maximum peak having a half-value width of 0.10 deg or more and 0.50 deg or less, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: March 26, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tsuyoshi Shimada, Kumiko Takizawa, Eileen Takeuchi, Ikuyo Kuroiwa, Wataru Kitamura, Kan Tanabe, Haruhiko Mitsuda
  • Publication number: 20180314173
    Abstract: There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus that are excellent in charging properties and can suppress residual potential in the case where a strontium titanate particle is used as a metal oxide particle in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member in which an undercoat layer contains a strontium titanate particle having a maximum peak at a position of 2?=32.20±0.20 (? represents a Bragg angle) in a CuK? characteristic X-ray diffraction pattern, the maximum peak having a half-value width of 0.10 deg or more and 0.50 deg or less, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.
    Type: Application
    Filed: April 24, 2018
    Publication date: November 1, 2018
    Inventors: Tsuyoshi Shimada, Kumiko Takizawa, Eileen Takeuchi, Ikuyo Kuroiwa, Wataru Kitamura, Kan Tanabe, Haruhiko Mitsuda