Patents by Inventor Tomohito Ishida

Tomohito Ishida 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: 11249407
    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: Grant
    Filed: June 18, 2020
    Date of Patent: February 15, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kaname Watariguchi, Tomohito Ishida, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi
  • Patent number: 11237493
    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: Grant
    Filed: June 17, 2020
    Date of Patent: February 1, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kohei Makisumi, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Michiyo Sekiya
  • Patent number: 11181837
    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: Grant
    Filed: June 18, 2020
    Date of Patent: November 23, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Michiyo Sekiya, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Kohei Makisumi
  • Publication number: 20210325794
    Abstract: There is provided an electrophotographic photosensitive member having drum shape, the electrophotographic photosensitive member including a support and a photosensitive layer, wherein an outer surface of the electrophotographic photosensitive member has wrinkles, and when an observation region having square form with one side of 100 ?m is placed at an arbitrary position on the outer surface, a line that passes through a central point of the observation region and is parallel to a circumferential direction of the electrophotographic photosensitive member is defined as a first reference line L1, and 3,599 reference lines obtained by rotating the first reference line L1 at every 0.1° around the central point are defined as L2 to L3,600, respectively, each of L1 to L3,600 intersects with convex portions of the wrinkles at a plurality of locations and has at least two different intersection angles selected from the plurality of locations.
    Type: Application
    Filed: April 14, 2021
    Publication date: October 21, 2021
    Inventors: Shuhei Iwasaki, Tomohito Ishida, Nobuhiro Nakamura, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka Ishiduka, Yota Ito, Takeshi Murakami
  • Publication number: 20210325793
    Abstract: A method for producing an electrophotographic photosensitive member including: forming a photosensitive layer; and forming a protective layer, wherein the step of forming the photosensitive layer forms a photosensitive layer having an amount of residual solvent of a first solvent in the photosensitive layer of 0.05% to 2.50% and an amount of residual solvent of a second solvent in the photosensitive layer of 0.50% to 2.50%, and the step of forming the protective layer includes step (A) of forming a cured film and step (B) of forming the protective layer having wrinkle shapes, wherein, in step (A), the irradiated coating film is heated at a heating temperature lower than a boiling point of the first solvent and in step (B), the cured film is heated at a heating temperature higher than a boiling point of the first solvent.
    Type: Application
    Filed: April 13, 2021
    Publication date: October 21, 2021
    Inventors: Nobuhiro Nakamura, Tomohito Ishida, Shuhei Iwasaki, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka lshiduka, Yota Ito, Takeshi Murakami
  • Publication number: 20210325814
    Abstract: Provided is an electrophotographic photosensitive drum that achieves both of a reduction in torque of the electrophotographic photosensitive drum at the time of its cleaning and an improvement in image transferability. The electrophotographic photosensitive drum includes: a support; and a photosensitive layer arranged on the support, the electrophotographic photosensitive drum having arranged on an outer surface thereof at least two structure groups having different appearance periods, wherein when, out of the two structure groups, a group including structures having a smaller appearance period is defined as a first structure group, and a group including structures having a larger appearance period is defined as a second structure group, a height of the first structure group is lower than a height of the second structure group.
    Type: Application
    Filed: April 13, 2021
    Publication date: October 21, 2021
    Inventors: Tomohito Ishida, Nobuhiro Nakamura, Shuhei Iwasaki, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka lshiduka, Yota Ito, Takeshi Murakami
  • Patent number: 11126097
    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: Grant
    Filed: June 18, 2020
    Date of Patent: September 21, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tomohito Ishida, Kaname Watariguchi, Masataka Kawahara, Michiyo Sekiya, 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: 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: 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
  • 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
  • Patent number: 10539888
    Abstract: An electrophotographic photosensitive member includes an electroconductive support member and a photosensitive layer. The uppermost layer of the electrophotographic photosensitive member defines a surface layer, and the surface layer contains polytetrafluoroethylene particles, a charge transporting material, and polyvinyl acetal. The proportion of the polyvinyl acetal content to the polytetrafluoroethylene particles content in the surface layer is in the range of 0.1% by mass to 15.0% by mass, and the charge transporting material content in the surface layer is 35% by mass or more relative to the total mass of the surface layer.
    Type: Grant
    Filed: June 13, 2018
    Date of Patent: January 21, 2020
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kenichi Kaku, Kaname Watariguchi, Kazuko Araki, Tomohito Ishida, Michiyo Sekiya
  • Publication number: 20190004442
    Abstract: An electrophotographic photosensitive member includes an electroconductive support member and a photosensitive layer. The uppermost layer of the electrophotographic photosensitive member defines a surface layer, and the surface layer contains polytetrafluoroethylene particles, a charge transporting material, and polyvinyl acetal. The proportion of the polyvinyl acetal content to the polytetrafluoroethylene particles content in the surface layer is in the range of 0.1% by mass to 15.0% by mass, and the charge transporting material content in the surface layer is 35% by mass or more relative to the total mass of the surface layer.
    Type: Application
    Filed: June 13, 2018
    Publication date: January 3, 2019
    Inventors: Kenichi Kaku, Kaname Watariguchi, Kazuko Araki, Tomohito Ishida, Michiyo Sekiya
  • Publication number: 20170146930
    Abstract: A developing apparatus of the present disclosure includes a developing sleeve including a plurality of magnetic substance portions bearing, on a surface thereof, developer containing toner and carrier and conveying the developer to a developing area facing a photosensitive drum, and a magnet roller disposed within the developing sleeve and generating magnetic fluxes passing through the magnetic substance portion. The magnetic substance portion includes, on an end surface thereof, a high flux density portion disposed at least one of upstream and downstream parts in a conveyance direction of the developing sleeve and through which the magnetic fluxes pass and a low flux density portion through which the magnetic fluxes whose density is lower than the magnetic fluxes passing through the high flux density portion pass.
    Type: Application
    Filed: November 15, 2016
    Publication date: May 25, 2017
    Inventors: Shunichi Takada, Tomohito Ishida, Kenta Kubo, Koichi Hashimoto, Tatsuya Onishi
  • Patent number: 9488945
    Abstract: An image forming apparatus that can reduce a toner bearing amount stably regardless of a density of an image. The image forming apparatus comprises a first generating unit which generates a reference pattern, and a second generating unit which generates, based on image data, a correction pattern for thinning out dots at a region from halftone density to high density. The image data is converted based on the reference pattern generated by the first generating unit and the correction pattern generated by the second generating unit. The image forming apparatus further comprises a photoreceptor. The photoreceptor is charged, the charged photoreceptor is exposed based on the converted image data to form an electrostatic latent image, and the electrostatic latent image is developed.
    Type: Grant
    Filed: August 21, 2015
    Date of Patent: November 8, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tomohito Ishida, Tetsuya Atsumi, Megumi Uchino, Shunichi Takada
  • Publication number: 20160299453
    Abstract: An exposure unit forms an electrostatic latent image on the surface of the photoconductor by exposing a photoconductor charged by a charging unit. The electrostatic latent image includes a patterned latent image having a periodic pattern and a printing latent image according to image information to be printed. The patterned latent image includes exposed sections exposed by the exposure unit and unexposed sections less exposed than the exposed sections. Each of the exposed sections occupies 30% or more and 70% or less of an area of one period of the patterned latent image. The period of the patterned latent image in a width direction intersecting the periodic pattern is 100% or more and less than 400% of an average particle diameter of the toner.
    Type: Application
    Filed: March 24, 2016
    Publication date: October 13, 2016
    Inventors: Tomohito Ishida, Shunichi Takada, Koichi Hashimoto, Yukio Nagase
  • Patent number: 9454103
    Abstract: A developing device includes a developing member and a carrier collecting member. An outer surface of the developing member includes a plurality of protrusion portions aligned at regular intervals that are equal to or larger than an average particle diameter of toner particles and smaller than an average particle diameter of magnetic carrier particles. Each protrusion portion has a first face formed at one side of an apex of each protrusion portion and a second face formed at the other side of the apex, and an inclination angle of the first face is less than an inclination angle of the second face. In the circumferential direction of the developing member, when a downward direction of the first face is set to be positive, a relative velocity of a surface velocity of an image bearing member to a surface velocity of the developing member is set to be positive.
    Type: Grant
    Filed: February 3, 2015
    Date of Patent: September 27, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kenta Kubo, Tomohito Ishida, Shunichi Takada, Koichi Hashimoto, Tatsuya Tada
  • Publication number: 20160062290
    Abstract: An image forming apparatus that can reduce a toner bearing amount stably regardless of a density of an image. The image forming apparatus comprises a first generating unit which generates a reference pattern, and a second generating unit which generates, based on image data, a correction pattern for thinning out dots at a region from halftone density to high density. The image data is converted based on the reference pattern generated by the first generating unit and the correction pattern generated by the second generating unit. The image forming apparatus further comprises a photoreceptor. The photoreceptor is charged, the charged photoreceptor is exposed based on the converted image data to form an electrostatic latent image, and the electrostatic latent image is developed.
    Type: Application
    Filed: August 21, 2015
    Publication date: March 3, 2016
    Inventors: Tomohito Ishida, Tetsuya Atsumi, Megumi Uchino, Shunichi Takada
  • Publication number: 20160011539
    Abstract: An image forming apparatus includes: an image bearing member; an electric potential sensor which detects electric potential of a toner image; a density sensor which acquires information of a density of the toner image; and a controller which controls contrast electric potential and the AC bias based on a result of the detection of the density sensor and a predetermined target value, wherein the controller decreases the development contrast, and increases the AC bias, when a charging electric potential difference, which is a potential difference between a potential of a predetermined toner image developed by the development device on the image bearing member and the DC bias applied to the development device when the predetermined toner image is developed, increases from a first predetermined value to a second predetermined value;
    Type: Application
    Filed: July 2, 2015
    Publication date: January 14, 2016
    Inventors: Tomohito Ishida, Tetsuya Atsumi, Kenta Kubo, Megumi Uchino, Shunichi Takada
  • Publication number: 20150227087
    Abstract: An image forming apparatus includes: a developing container; a concave-convex member which has a plurality of grooves formed in a rotation direction; a collecting portion; and a receiving member, wherein each groove has side surfaces including a first side surface formed in one direction and a second side surface formed in the other direction in a circumferential direction of the concave-convex member, wherein the first side surface has a smaller inclination angle than the second side surface, and when a direction which moves down the first side surface in the circumferential direction of the concave-convex member is set to be positive, a relative velocity of a surface velocity of the concave-convex member to a surface velocity of the receiving member is set to be positive, at a position in which the concave-convex member and the receiving member come into contact with each other.
    Type: Application
    Filed: February 3, 2015
    Publication date: August 13, 2015
    Inventors: Kenta Kubo, Tomohito Ishida, Shunichi Takada, Koichi Hashimoto, Tatsuya Tada