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).
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Publication number: 20240118634Abstract: The electrophotographic photosensitive member includes a support and a photosensitive layer on the support, in which a surface layer of the electrophotographic photosensitive member contains a particle, the surface layer has a particle partially exposed from the surface layer among the particle contained in the surface layer, the particle has a volume average particle diameter of 50.0 nm or more and 350.0 nm or less; in a cross-section of the surface layer, the number of the particle partially exposed from the surface layer is 80% by number or more based on a total number of the particle contained in the surface layer; and a total volume of an exposed portion of the particle partially exposed from the surface layer is 30% by volume or more and 80% by volume or less based on an entire volume of the particle contained in the surface layer.Type: ApplicationFiled: November 30, 2023Publication date: April 11, 2024Inventors: SHUNTARO WATANABE, TOMOHITO ISHIDA, NOBUHIRO NAKAMURA, HIROYUKI WATANABE, TATSUYA YAMAAI, MASATADA HIROTA
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Publication number: 20240118635Abstract: Provided is an electrophotographic photosensitive member that achieves satisfactory transferability. An electrophotographic photosensitive member including a charge generating layer, a charge transporting layer, and a protection layer laminated on a support in the stated order, wherein the protection layer contains a binder resin and particles, and wherein when an average thickness of the protection layer in a site free of the particles is represented by T and a volume-average particle diameter of the particles is represented by Dm in a cross-section of the protection layer, the following formula (a) is satisfied.Type: ApplicationFiled: November 30, 2023Publication date: April 11, 2024Inventors: TOMOHITO ISHIDA, SHUNTARO WATANABE, NOBUHIRO NAKAMURA, TATSUYA YAMAAI, HIROYUKI WATANABE, MASATADA HIROTA
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Publication number: 20240004322Abstract: The electrophotographic photosensitive member includes a surface layer containing a binder resin, electroconductive particles, and insulating particles, wherein when a volume resistivity of the insulating particles is represented by R1 [?·cm], a volume resistivity of the electroconductive particles is represented by R2 [?·cm], a ratio of an area of the insulating particles that are exposed to a total area of the surface layer is represented by S1 [%], a ratio of an area of the electroconductive particles that are exposed to the total area of the surface layer is represented by S2 [%], an average exposed height of the insulating particles exposed to a surface of the electrophotographic photosensitive member is represented by L1 [nm], and an average exposed height of the electroconductive particles exposed to the surface of the electrophotographic photosensitive member is represented by L2 [nm], those parameters satisfy specific relational formulae.Type: ApplicationFiled: June 23, 2023Publication date: January 4, 2024Inventors: KOHEI MAKISUMI, SHUNTARO WATANABE, TAICHI SATO, TOMOHITO ISHIDA, MASATADA HIROTA, TSUTOMU NISHIDA
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Publication number: 20230408937Abstract: An electrophotographic photosensitive member including a surface layer containing a binder resin and metal oxide particles. An average primary particle diameter of the metal oxide particles measured from a cross-section of the surface layer is 20 to 70 nm. A content ratio of the metal oxide particles in the surface layer measured from the cross-section of the surface layer is 30 to 75 vol % with respect to a total volume of the surface layer.Type: ApplicationFiled: June 16, 2023Publication date: December 21, 2023Inventors: TAICHI SATO, SHUNTARO WATANABE, MASATADA HIROTA, KOHEI MAKISUMI, TOMOHITO ISHIDA, TSUTOMU NISHIDA
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Patent number: 11782353Abstract: 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: GrantFiled: April 13, 2021Date of Patent: October 10, 2023Assignee: CANON KABUSHIKI KAISHAInventors: Nobuhiro Nakamura, Tomohito Ishida, Shuhei Iwasaki, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka Ishiduka, Yota Ito, Takeshi Murakami
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Patent number: 11619907Abstract: A process cartridge including: an electrophotographic photosensitive member having a drum shape; a developing unit for developing an electrostatic latent image on the surface of the electrophotographic photosensitive member with toner; and a cleaning blade for removing the toner on the surface of the electrophotographic photosensitive member, the cleaning blade being in contact with the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises wrinkles on the surface of the electrophotographic photosensitive member, and wherein the toner has a fluidity torque E of 320 mJ or more.Type: GrantFiled: March 8, 2022Date of Patent: April 4, 2023Assignee: Canon Kabushiki KaishaInventors: Fumiyuki Hiyama, Shuhei Iwasaki, Hiroyuki Watanabe, Nobuhiro Nakamura, Tomohito Ishida, Shuntaro Watanabe
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Publication number: 20220291627Abstract: A process cartridge including: an electrophotographic photosensitive member having a drum shape; a developing unit for developing an electrostatic latent image on the surface of the electrophotographic photosensitive member with toner; and a cleaning blade for removing the toner on the surface of the electrophotographic photosensitive member, the cleaning blade being in contact with the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises wrinkles on the surface of the electrophotographic photosensitive member, and wherein the toner has a fluidity torque E of 320 mJ or more.Type: ApplicationFiled: March 8, 2022Publication date: September 15, 2022Inventors: Fumiyuki Hiyama, Shuhei Iwasaki, Hiroyuki Watanabe, Nobuhiro Nakamura, Tomohito Ishida, Shuntaro Watanabe
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Publication number: 20220291600Abstract: In an electrophotographic photosensitive member, wrinkles have a convex portion in which a linear shape portion having a length of 50 ?m or longer exists, the linear shape portion is parallel to any one of L1 to L150 and L1651 to L1800, and each of L1 to L1800 intersects with the convex portion at a plurality of places, and at least two of the places have different intersection angles; and when height information of the wrinkles is subjected to a frequency analysis, and a two-dimensional power spectrum is obtained, a one-dimensional radial distribution function has at least one local maximum value, and when an angular distribution is calculated from the spectrum at a frequency of the local maximum value, the power values have a particular relationship.Type: ApplicationFiled: March 4, 2022Publication date: September 15, 2022Inventors: Nobuhiro Nakamura, Tomohito Ishida, Shuhei Iwasaki, Hiroyuki Watanabe, Fumiyuki Hiyama, Shuntaro Watanabe
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Patent number: 11392074Abstract: 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: GrantFiled: April 13, 2021Date of Patent: July 19, 2022Assignee: CANON KABUSHIKI KAISHAInventors: Tomohito Ishida, Nobuhiro Nakamura, Shuhei Iwasaki, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka Ishiduka, Yota Ito, Takeshi Murakami
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Patent number: 11249407Abstract: 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: GrantFiled: June 18, 2020Date of Patent: February 15, 2022Assignee: CANON KABUSHIKI KAISHAInventors: Kaname Watariguchi, Tomohito Ishida, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi
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Patent number: 11237493Abstract: 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: GrantFiled: June 17, 2020Date of Patent: February 1, 2022Assignee: CANON KABUSHIKI KAISHAInventors: Kohei Makisumi, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Michiyo Sekiya
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Patent number: 11181837Abstract: 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: GrantFiled: June 18, 2020Date of Patent: November 23, 2021Assignee: CANON KABUSHIKI KAISHAInventors: Michiyo Sekiya, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Kohei Makisumi
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Publication number: 20210325814Abstract: 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: ApplicationFiled: April 13, 2021Publication date: October 21, 2021Inventors: Tomohito Ishida, Nobuhiro Nakamura, Shuhei Iwasaki, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka lshiduka, Yota Ito, Takeshi Murakami
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Publication number: 20210325793Abstract: 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: ApplicationFiled: April 13, 2021Publication date: October 21, 2021Inventors: Nobuhiro Nakamura, Tomohito Ishida, Shuhei Iwasaki, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka lshiduka, Yota Ito, Takeshi Murakami
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Publication number: 20210325794Abstract: 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: ApplicationFiled: April 14, 2021Publication date: October 21, 2021Inventors: Shuhei Iwasaki, Tomohito Ishida, Nobuhiro Nakamura, Hiroyuki Watanabe, Tatsuya Yamaai, Yuka Ishiduka, Yota Ito, Takeshi Murakami
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Patent number: 11126097Abstract: 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: GrantFiled: June 18, 2020Date of Patent: September 21, 2021Assignee: CANON KABUSHIKI KAISHAInventors: Tomohito Ishida, Kaname Watariguchi, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi
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Publication number: 20200409281Abstract: 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: ApplicationFiled: June 18, 2020Publication date: December 31, 2020Inventors: Kaname Watariguchi, Tomohito Ishida, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi
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Publication number: 20200409278Abstract: 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: ApplicationFiled: June 17, 2020Publication date: December 31, 2020Inventors: Kohei Makisumi, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Michiyo Sekiya
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Publication number: 20200409279Abstract: 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: ApplicationFiled: June 18, 2020Publication date: December 31, 2020Inventors: Michiyo Sekiya, Kaname Watariguchi, Masataka Kawahara, Tomohito Ishida, Kohei Makisumi
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Publication number: 20200409280Abstract: 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: ApplicationFiled: June 18, 2020Publication date: December 31, 2020Inventors: Tomohito Ishida, Kaname Watariguchi, Masataka Kawahara, Michiyo Sekiya, Kohei Makisumi