Patents by Inventor Masataka Kawahara

Masataka Kawahara 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).

  • Publication number: 20200409279
    Abstract: An electrophotographic photosensitive member, including a cylindrical support, a charge generating layer formed on the cylindrical support, and a charge transport layer formed on the charge generating layer, in which in the charge generating layer, when a region from a central position of an image forming region to an end position of the image forming region in an axis direction of the cylindrical support is divided equally into five regions, film thicknesses of the charge generating layers in each of the regions satisfy a specific relationship with each other, and in the charge transport layer, when a region from the central position of the image forming region to the end position of the image forming region in the axis direction of the cylindrical support is divided equally into five regions, film thicknesses of the charge transport layers in each of the regions satisfy a specific relationship with each other.
    Type: Application
    Filed: June 18, 2020
    Publication date: December 31, 2020
    Inventors: Michiyo Sekiya, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Kohei Makisumi
  • Publication number: 20200409281
    Abstract: The electrophotographic photosensitive member has: a cylindrical support; a charge generating layer formed on the cylindrical support; and a charge transport layer formed on the charge generating layer, the charge generating layer contains a hydroxygallium phthalocyanine crystal having a particular CuK? characteristic X-ray diffraction peak, a titanyl phthalocyanine crystal having a particular CuK? characteristic X-ray diffraction peak or a chlorogallium phthalocyanine crystal having a particular spectral absorption spectrum as a charge generating material, and in the charge generating layer, with respect to the film thickness of the charge generating layer, when a region from the central position of an image forming area to the end position of the image forming area is divided in the axial direction of the cylindrical support into five equal regions and the average film thickness of the charge generating layer in each region satisfies a specific condition.
    Type: Application
    Filed: June 18, 2020
    Publication date: December 31, 2020
    Inventors: Kaname Watariguchi, Tomohito Ishida, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi
  • Publication number: 20200409278
    Abstract: Provided is an electrophotographic photosensitive member which enables a reduction in unevenness in distribution of the post-exposure potential of the photosensitive member and a reduction in unevenness in life of the photosensitive member in the axial direction. An electrophotographic photosensitive member, including a cylindrical support, a charge generating layer, and a charge transport layer in this order, wherein when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in the axial direction of the cylindrical support is equally divided into five regions, average film thicknesses of the charge generating layer in the five regions satisfy specific relations in a film thickness of the charge generating layer and average film thicknesses of the charge transport layer in the five regions satisfy specific relations in a film thickness of the charge transport layer.
    Type: Application
    Filed: June 17, 2020
    Publication date: December 31, 2020
    Inventors: Kohei Makisumi, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Michiyo Sekiya
  • Publication number: 20200409280
    Abstract: Provided is an electrophotographic photosensitive member in which discharge streaks generated in an end portion can be suppressed. The electrophotographic photosensitive member includes a cylindrical support, a charge-generating layer, and a charge-transporting layer in the stated order. In the electrophotographic photosensitive member, when a region between a center position and a 90% position situated at a 90% of a length of from the center position to one end of the electrophotographic photosensitive member in an axial direction thereof from the center position, is defined as a region X, and a region between the 90% position and the end of the electrophotographic photosensitive member is defined as a region Z. Average thicknesses in regions obtained by equally dividing the region X into five and regions obtained by equally dividing the region Z into three satisfy particular relationships.
    Type: Application
    Filed: June 18, 2020
    Publication date: December 31, 2020
    Inventors: Tomohito Ishida, Kaname Watariguchi, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi
  • Patent number: 10838313
    Abstract: An electrophotographic photosensitive member includes, in this order, a support, a charge generating layer having a thickness of more than 200 nm and containing a hydroxygallium phthalocyanine pigment or a chlorogallium phthalocyanine pigment as a charge generating material, and a charge transport layer containing a charge transporting material. The charge generating material satisfies a requirement for a specific parameter.
    Type: Grant
    Filed: April 23, 2018
    Date of Patent: November 17, 2020
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazuko Araki, Kaname Watariguchi, Masataka Kawahara, Jumpei Kuno
  • Patent number: 10429753
    Abstract: An electrophotographic photoconductor comprises a support, an undercoat layer, a charge generation layer, and a hole transport layer in this order. The undercoat layer comprises an electron transport substance, and the charge generation layer comprises a gallium phthalocyanine crystal and an amide compound represented by formula (N1): where R1 represents a methyl group, a propyl group, or a vinyl group.
    Type: Grant
    Filed: February 25, 2016
    Date of Patent: October 1, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kaname Watariguchi, Masato Tanaka, Masataka Kawahara, Jumpei Kuno
  • Patent number: 10401746
    Abstract: An electrophotographic photosensitive member includes a support member, a charge generating layer containing a phthalocyanine pigment as a charge generating material, a charge transport layer containing a charge transporting material in this order. The charge generating layer has a thickness of less than 200 nm, and the phthalocyanine pigment includes phthalocyanine crystalline particles having a particle size distribution and satisfies a requirement that the volume average of the products of ?i and ?i is 0.31 or more.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: September 3, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kaname Watariguchi, Shoma Hinata, Kazuko Araki, Tsutomu Nishida, Jumpei Kuno, Masataka Kawahara, Yuto Ito, Isao Kawata
  • Publication number: 20180314170
    Abstract: An electrophotographic photosensitive member includes, in this order, a support, a charge generating layer having a thickness of more than 200 nm and containing a hydroxygallium phthalocyanine pigment or a chlorogallium phthalocyanine pigment as a charge generating material, and a charge transport layer containing a charge transporting material. The charge generating material satisfies a requirement for a specific parameter.
    Type: Application
    Filed: April 23, 2018
    Publication date: November 1, 2018
    Inventors: Kazuko Araki, Kaname Watariguchi, Masataka Kawahara, Jumpei Kuno
  • Publication number: 20180314171
    Abstract: An electrophotographic photosensitive member includes a support member, a charge generating layer containing a phthalocyanine pigment as a charge generating material, a charge transport layer containing a charge transporting material in this order. The charge generating layer has a thickness of less than 200 nm, and the phthalocyanine pigment includes phthalocyanine crystalline particles having a particle size distribution and satisfies a requirement that the volume average of the products of ?i and ?i is 0.31 or more.
    Type: Application
    Filed: April 24, 2018
    Publication date: November 1, 2018
    Inventors: Kaname Watariguchi, Shoma Hinata, Kazuko Araki, Tsutomu Nishida, Jumpei Kuno, Masataka Kawahara, Yuto Ito, Isao Kawata
  • Patent number: 10012915
    Abstract: An electrophotographic photosensitive member includes a support and a photosensitive layer in this order. The photosensitive layer contains a chlorogallium phthalocyanine crystal obtained by mixing a hydroxygallium phthalocyanine crystal and an aqueous hydrochloric acid solution.
    Type: Grant
    Filed: June 30, 2017
    Date of Patent: July 3, 2018
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tsutomu Nishida, Masato Tanaka, Masataka Kawahara, Jumpei Kuno, Kaname Watariguchi, Hidetoshi Hirano
  • Patent number: 9921499
    Abstract: An electrophotographic photosensitive member includes a substrate and a photosensitive layer containing a phthalocyanine pigment. The crystalline particles of the phthalocyanine pigment have a crystallite correlation length r and a particle size R of 400 nm or less, and a parameter k defined by r/R is in the range of 0.17 to 0.42.
    Type: Grant
    Filed: October 26, 2016
    Date of Patent: March 20, 2018
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kaname Watariguchi, Shoma Hinata, Kazuko Sakuma, Tsutomu Nishida, Jumpei Kuno, Hirofumi Kumoi, Masato Tanaka, Masataka Kawahara, Yuto Ito, Isao Kawata
  • Patent number: 9869032
    Abstract: The present invention provides: an electrophotographic photosensitive member which reduces image defects due to ghosting not only under a normal temperature and normal humidity environment but also even under a low temperature and low humidity environment; and a novel phthalocyanine crystal. The electrophotographic photosensitive member of the present invention comprises a photosensitive layer which comprises a phthalocyanine crystal in which a N,N-dimethylformamide is contained. The content of the N,N-dimethylformamide is 0.1% by mass or more and 1.5% by mass or less based on the phthalocyanine crystal.
    Type: Grant
    Filed: November 28, 2016
    Date of Patent: January 16, 2018
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Masataka Kawahara, Masato Tanaka, Jumpei Kuno, Tsutomu Nishida, Kaname Watariguchi
  • Patent number: 9864284
    Abstract: An electrophotographic photosensitive member has a support, a charge generation layer, and a charge transport layer in this order, the charge transport layer containing a charge transport material. The charge transport layer is a surface layer of the electrophotographic photosensitive member and contains a polycarbonate resin having a structural unit selected from group A and a structural unit selected from group B.
    Type: Grant
    Filed: February 25, 2016
    Date of Patent: January 9, 2018
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masataka Kawahara, Hirotoshi Uesugi, Akihiro Maruyama, Hirofumi Kumoi, Masato Tanaka, Hiroyuki Tomono, Shoma Hinata, Yota Ito, Daisuke Miura, Takashi Anezaki, Tatsuya Yamaai, Kazumichi Sugiyama
  • Publication number: 20170299970
    Abstract: An electrophotographic photosensitive member includes a support and a photosensitive layer in this order. The photosensitive layer contains a chlorogallium phthalocyanine crystal obtained by mixing a hydroxygallium phthalocyanine crystal and an aqueous hydrochloric acid solution.
    Type: Application
    Filed: June 30, 2017
    Publication date: October 19, 2017
    Inventors: Tsutomu Nishida, Masato Tanaka, Masataka Kawahara, Jumpei Kuno, Kaname Watariguchi, Hidetoshi Hirano
  • Patent number: 9753385
    Abstract: An electrophotographic photosensitive member has a support, a charge generation layer, and a charge transport layer in this order, the charge transport layer containing a charge transport material. The charge transport layer is a surface layer of the electrophotographic photosensitive member and contains a polycarbonate resin having a structural unit selected from group A and a structural unit selected from group B (groups A and B defined in the disclosure).
    Type: Grant
    Filed: February 25, 2016
    Date of Patent: September 5, 2017
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yota Ito, Daisuke Miura, Shoma Hinata, Hiroyuki Tomono, Takashi Anezaki, Tatsuya Yamaai, Kazumichi Sugiyama, Masataka Kawahara, Hirotoshi Uesugi, Akihiro Maruyama, Hirofumi Kumoi, Masato Tanaka
  • Patent number: 9746790
    Abstract: An electrophotographic photosensitive member includes a support and a photosensitive layer in this order. The photosensitive layer contains a chlorogallium phthalocyanine crystal represented by formula (1) in which at least one organic compound selected from N,N-dimethylformamide and dimethyl sulfoxide is contained. The content of the organic compound contained in the chlorogallium phthalocyanine crystal represented by the formula (1) is 0.10 mass % or more and 0.80 mass % or less based on a content of the chlorogallium phthalocyanine crystal represented by the formula (1).
    Type: Grant
    Filed: October 22, 2015
    Date of Patent: August 29, 2017
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tsutomu Nishida, Masato Tanaka, Masataka Kawahara
  • Patent number: 9720337
    Abstract: An electrophotographic photosensitive member includes a support and a photosensitive layer in this order. The photosensitive layer contains a chlorogallium phthalocyanine crystal. The chlorogallium phthalocyanine crystal has one or more peaks in each of a wavelength range of 646 nm or more and 668 nm or less and a wavelength range of 782 nm or more and 809 nm or less in an absorption spectrum. When a peak with a maximum absorbance among the peaks in the wavelength range of 646 nm or more and 668 nm or less is assumed to be a first peak and a peak with a maximum absorbance among the peaks in the wavelength range of 782 nm or more and 809 nm or less is assumed to be a second peak, an absorbance of the first peak is larger than an absorbance of the second peak.
    Type: Grant
    Filed: October 22, 2015
    Date of Patent: August 1, 2017
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tsutomu Nishida, Masato Tanaka, Masataka Kawahara
  • Patent number: 9709907
    Abstract: An electrophotographic photosensitive member can provide images in which black spots and fogging are suppressed and density unevenness due to coating unevenness of the charge generation layer is suppressed. The charge generation layer of the electrophotographic photosensitive member contains a gallium phthalocyanine crystal, a nitrogen-containing heterocyclic compound, and an amide compound represented by a formula (1), and a nitrogen atom in a heterocyclic ring of the nitrogen-containing heterocyclic compound has a substituent.
    Type: Grant
    Filed: June 11, 2015
    Date of Patent: July 18, 2017
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kaname Watariguchi, Masato Tanaka, Masataka Kawahara, Jumpei Kuno, Tsutomu Nishida
  • Patent number: 9645516
    Abstract: An electrophotographic photosensitive member including a support, and a charge generating layer and a charge transporting layer on the support, wherein the charge generating layer includes a gallium phthalocyanine crystal in which an organic compound is contained, wherein the organic compound is at least one compound selected from the group consisting of dimethylsulfoxide, N,N-dimethylformamide, N-methylformamide, N-propylformamide, N-vinylformamide and N-methylpyrrolidone, the content of the organic compound is 0.1% by mass or more and 1.5% or less based on a gallium phthalocyanine in the gallium phthalocyanine crystal, and the charge transporting layer includes a polyester resin having a structural unit represented by formula (1). A-B??(1).
    Type: Grant
    Filed: November 9, 2015
    Date of Patent: May 9, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Masataka Kawahara, Masato Tanaka, Jumpei Kuno, Tsutomu Nishida, Kaname Watariguchi
  • Patent number: 9645515
    Abstract: An electrophotographic photosensitive member capable of outputting an image with suppressed positive ghosting, and a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member are provided. The electrophotographic photosensitive member has a photosensitive layer including a phthalocyanine crystal in which the compound represented by the formula (1) is contained, wherein the content of the compound represented by the formula (1) is 0.1% by mass or more and 1.7% by mass or less based on the phthalocyanine crystal.
    Type: Grant
    Filed: April 17, 2015
    Date of Patent: May 9, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Junpei Kuno, Tsutomu Nishida, Masato Tanaka, Masataka Kawahara, Kaname Watariguchi