Patents by Inventor Sara Yoshida

Sara Yoshida 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: 11960242
    Abstract: The present invention provides a toner that can maintain excellent transferability even when a transfer bias is low. The toner includes a toner particle that includes a toner base particle and a plurality of convex portions X existing on a surface of the toner base particle, wherein the convex portion X contains an organic silicon polymer; when a cross-section of the toner is observed with a scanning transmission electron microscope (STEM), and the convex portions X comprise a plurality of convex portions Y each having a convex height H of 40 nm or higher, a number ratio P (H/w) of the a number of the convex portions Y2 in which a ratio (H/w) of the convex height H to the convex width w is 0.33 or larger and 0.80 or smaller is 70% by number or more with respect to a total number of the convex portions Y.
    Type: Grant
    Filed: October 12, 2021
    Date of Patent: April 16, 2024
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kentaro Yamawaki, Sara Yoshida, Yusuke Kosaki, Taiji Katsura, Hidekazu Fumita, Toshiya Kaino
  • Patent number: 11841681
    Abstract: A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied: A?90??(I) 100?B?1000??(II).
    Type: Grant
    Filed: June 15, 2021
    Date of Patent: December 12, 2023
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Taiji Katsura, Hidekazu Fumita, Kentaro Yamawaki, Sara Yoshida, Yusuke Kosaki, Takayoshi Ootsuka
  • Patent number: 11573519
    Abstract: The electrophotographic apparatus and process cartridge comprising an electrophotographic photosensitive member, a cleaning blade, and developing unit containing a toner, wherein the cleaning blade comprising a support member and an elastic member whose portion is abutting a surface of the electrophotographic photosensitive member; the elastic member has an elastic modulus of 15 to 470 MPa with coefficient of variation for the elastic modulus being not more than 7.0%, and the absolute value of a difference between Martens hardness values is not more than 0.30 N/mm2 as measured under prescribed conditions; the toner contains a toner particle and an external additive whose a number-average primary particle diameter is from 5 to 25 nm, when X1 is a coverage ratio of the toner particle by the external additive and X2 is a theoretical coverage ratio, X1 is 50 to 85 area %, and X1/X2??0.0042×X1+0.60 is satisfied.
    Type: Grant
    Filed: March 18, 2022
    Date of Patent: February 7, 2023
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Hidekazu Fumita, Kentaro Yamawaki, Sara Yoshida, Yusuke Kosaki, Taiji Katsura, Syoji Inoue, Arihiro Yamamoto
  • Publication number: 20220334530
    Abstract: The electrophotographic apparatus and process cartridge comprising an electrophotographic photosensitive member, a cleaning blade, and developing unit containing a toner, wherein the cleaning blade comprising a support member and an elastic member whose portion is abutting a surface of the electrophotographic photosensitive member; the elastic member has an elastic modulus of 15 to 470 MPa with coefficient of variation for the elastic modulus being not more than 7.0%, and the absolute value of a difference between Martens hardness values is not more than 0.30 N/mm2 as measured under prescribed conditions; the toner contains a toner particle and an external additive whose a number-average primary particle diameter is from 5 to 25 nm, when X1 is a coverage ratio of the toner particle by the external additive and X2 is a theoretical coverage ratio, X1 is 50 to 85 area %, and X1/X2??0.0042×X1+0.60 is satisfied.
    Type: Application
    Filed: March 18, 2022
    Publication date: October 20, 2022
    Inventors: Hidekazu Fumita, Kentaro Yamawaki, Sara Yoshida, Yusuke Kosaki, Taiji Katsura, Syoji Inoue, Arihiro Yamamoto
  • Publication number: 20220121133
    Abstract: The present invention provides a toner that can maintain excellent transferability even when a transfer bias is low. The toner includes a toner particle that includes a toner base particle and a plurality of convex portions X existing on a surface of the toner base particle, wherein the convex portion X contains an organic silicon polymer; when a cross-section of the toner is observed with a scanning transmission electron microscope (STEM), and the convex portions X comprise a plurality of convex portions Y each having a convex height H of 40 nm or higher, a number ratio P (H/w) of the a number of the convex portions Y2 in which a ratio (H/w) of the convex height H to the convex width w is 0.33 or larger and 0.80 or smaller is 70% by number or more with respect to a total number of the convex portions Y.
    Type: Application
    Filed: October 12, 2021
    Publication date: April 21, 2022
    Inventors: Kentaro Yamawaki, Sara Yoshida, Yusuke Kosaki, Taiji Katsura, Hidekazu Fumita, Toshiya Kaino
  • Publication number: 20220121132
    Abstract: A toner including: a toner particle containing a binder resin and a colorant; and a fine particle on a surface of the toner particle, wherein the fine particle is a solid and substantially hemispherical shape, and has a substantially flat surface and a curved surface, and wherein a number-average value of a longest diameter “w” of the substantially flat surface is 10 to 400 nm. An external additive for a toner that is a solid and substantially hemispherical shape, and has a substantially flat surface and a curved surface, wherein a number-average value of a longest diameter “w” of the substantially flat surface is 10 to 400 nm. A fine particle that is a solid and substantially hemispherical shape, and has a substantially flat surface and a curved surface, wherein a number-average value of a longest diameter “w” of the substantially flat surface is 10 to 400 nm.
    Type: Application
    Filed: October 8, 2021
    Publication date: April 21, 2022
    Inventors: Sara Yoshida, Yusuke Kosaki, Taiji Katsura, Hidekazu Fumita, Kentaro Yamawaki, Itaru Kondo
  • Publication number: 20210397110
    Abstract: A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied: A?90??(I) 100?B?1000??(II).
    Type: Application
    Filed: June 15, 2021
    Publication date: December 23, 2021
    Inventors: Taiji Katsura, Hidekazu Fumita, Kentaro Yamawaki, Sara Yoshida, Yusuke Kosaki, Takayoshi Ootsuka
  • Patent number: 10545422
    Abstract: A toner comprising a binder resin and a colorant, wherein the toner has a Martens hardness, as measured at a maximum load condition of 2.0×10?4 N, of from 200 MPa to 1,100 MPa.
    Type: Grant
    Filed: April 8, 2019
    Date of Patent: January 28, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kentaro Yamawaki, Akane Masumoto, Tomonori Matsunaga, Kunihiko Nakamura, Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano, Toshihiko Katakura, Shiro Kuroki
  • Patent number: 10503090
    Abstract: Provided is a toner containing a colorant and a binder resin, wherein, in a wettability test of the toner with respect to a methanol/water mixed solvent, the methanol concentration when the transmittance of light at a wavelength of 780 nm is 50% is at least 5.0 volume % and not more than 30.0 volume %, and the interparticle force measured by rupturing a consolidation of the toner formed by compression of the toner with a load of 78.5 N is at least 1.0 nN and not more than 25.0 nN.
    Type: Grant
    Filed: May 2, 2018
    Date of Patent: December 10, 2019
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tsuneyoshi Tominaga, Akane Masumoto, Toshihiko Katakura, Shiro Kuroki, Kenta Kamikura, Sara Yoshida, Shinsuke Mochizuki, Tsutomu Shimano, Kentaro Yamawaki, Tomonori Matsunaga, Kunihiko Nakamura
  • Patent number: 10429757
    Abstract: A toner comprising a toner particle that contains a binder resin and a release agent, wherein the toner particle has a surface layer that contains an organosilicon polymer and the luminance histogram of a backscattered electron image of the toner particle has two peak values P1 and P2 and a minimum value V between P1 and P2, P2 originates from the organosilicon polymer, and the luminance giving P1 and P2 are in specific ranges, percentages for P1 and P2 are each at least 0.50%, and using the luminance Bl at V as a reference point, specific relationships are satisfied by A1, AV, and A2, where A1 is the total number of pixels at luminance from 0 to (Bl?30 ), AV is the total number of pixels at luminance from (Bl?29 ) to (Bl+29 ), and A2 is the total number of pixels at luminance from (Bl+30 ) to 255.
    Type: Grant
    Filed: May 8, 2018
    Date of Patent: October 1, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano, Kentaro Yamawaki, Akane Masumoto, Tomonori Matsunaga, Kunihiko Nakamura, Toshihiko Katakura, Shiro Kuroki
  • Publication number: 20190235406
    Abstract: A toner comprising a binder resin and a colorant, wherein the toner has a Martens hardness, as measured at a maximum load condition of 2.0×10?4 N, of from 200 MPa to 1,100 MPa.
    Type: Application
    Filed: April 8, 2019
    Publication date: August 1, 2019
    Inventors: Kentaro Yamawaki, Akane Masumoto, Tomonori Matsunaga, Kunihiko Nakamura, Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano, Toshihiko Katakura, Shiro Kuroki
  • Patent number: 10324399
    Abstract: An image forming apparatus includes an image bearing member, a developing device, and an intermediate transfer member. The developing device includes a toner container containing a toner. The intermediate transfer member is charged to 3.0 nC/g or less in terms of absolute value at the surface thereof. The toner particles include a surface layer, and the brightness histogram of the toner particles has two local maximums P1 and P2 and a local minimum V between P1 and P2. P2 is derived from an organosilicon polymer. P1 lies in a brightness range of 20 to 70, and P2 lies in a brightness range of 130 to 230. The number of pixels of P1 and the number of pixels of P2 are each 0.50% or more relative to the total number of pixels. The total numbers of pixels A1, AV, and A2 each in a specific brightness range satisfy specific relationships.
    Type: Grant
    Filed: August 22, 2018
    Date of Patent: June 18, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasutaka Yagi, Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano
  • Patent number: 10303074
    Abstract: A toner comprising a binder resin and a colorant, wherein the toner has a Martens hardness, as measured at a maximum load condition of 2.0×10?4 N, of from 200 MPa to 1,100 MPa.
    Type: Grant
    Filed: May 9, 2018
    Date of Patent: May 28, 2019
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kentaro Yamawaki, Akane Masumoto, Tomonori Matsunaga, Kunihiko Nakamura, Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano, Toshihiko Katakura, Shiro Kuroki
  • Publication number: 20190064705
    Abstract: An image forming apparatus includes an image bearing member, a developing device, and an intermediate transfer member. The developing device includes a toner container containing a toner. The intermediate transfer member is charged to 3.0 nC/g or less in terms of absolute value at the surface thereof. The toner particles include a surface layer, and the brightness histogram of the toner particles has two local maximums P1 and P2 and a local minimum between P1 and P2. P2 is derived from the organosilicon polymer. P1 lies in a brightness range of 20 to 70, and P2 lies in a brightness range of 130 to 230. The number of pixels of P1 and the number of pixels of P2 are each 0.50% or more relative to the total number of pixels. The total numbers of pixels A1, AV, and A2 each in a specific brightness range satisfy specific relationships.
    Type: Application
    Filed: August 22, 2018
    Publication date: February 28, 2019
    Inventors: Yasutaka Yagi, Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano
  • Publication number: 20180329320
    Abstract: A toner comprising a toner particle that contains a binder resin and a release agent, wherein the toner particle has a surface layer that contains an organosilicon polymer and the luminance histogram of a backscattered electron image of the toner particle has two peak values P1 and P2 and a minimum value V between P1 and P2, P2 originates from the organosilicon polymer, and the luminance giving P1 and P2 are in specific ranges, percentages for P1 and P2 are each at least 0.50%, and using the luminance Bl at V as a reference point, specific relationships are satisfied by A1, AV, and A2, where A1 is the total number of pixels at luminance from 0 to (Bl?30), AV is the total number of pixels at luminance from (Bl?29) to (Bl+29), and A2 is the total number of pixels at luminance from (Bl+30) to 255.
    Type: Application
    Filed: May 8, 2018
    Publication date: November 15, 2018
    Inventors: SARA YOSHIDA, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano, Kentaro Yamawaki, Akane Masumoto, Tomonori Matsunaga, Kunihiko Nakamura, Toshihiko Katakura, Shiro Kuroki
  • Publication number: 20180329332
    Abstract: Provided is a toner containing a colorant and a binder resin, wherein, in a wettability test of the toner with respect to a methanol/water mixed solvent, the methanol concentration when the transmittance of light at a wavelength of 780 nm is 50% is at least 5.0 volume % and not more than 30.0 volume %, and the interparticle force measured by rupturing a consolidation of the toner formed by compression of the toner with a load of 78.5 N is at least 1.0 nN and not more than 25.0 nN.
    Type: Application
    Filed: May 2, 2018
    Publication date: November 15, 2018
    Inventors: Tsuneyoshi Tominaga, Akane Masumoto, Toshihiko Katakura, Shiro Kuroki, Kenta Kamikura, Sara Yoshida, Shinsuke Mochizuki, Tsutomu Shimano, Kentaro Yamawaki, Tomonori Matsunaga, Kunihiko Nakamura
  • Publication number: 20180329327
    Abstract: A toner comprising a binder resin and a colorant, wherein the toner has a Martens hardness, as measured at a maximum load condition of 2.0×10?4 N, of from 200 MPa to 1,100 MPa.
    Type: Application
    Filed: May 9, 2018
    Publication date: November 15, 2018
    Inventors: Kentaro Yamawaki, Akane Masumoto, Tomonori Matsunaga, Kunihiko Nakamura, Sara Yoshida, Shinsuke Mochizuki, Tsuneyoshi Tominaga, Kenta Kamikura, Tsutomu Shimano, Toshihiko Katakura, Shiro Kuroki
  • Patent number: 9897933
    Abstract: Provided is a toner that is excellent in development durability and has excellent solid followability even when the amount of the toner in a toner cartridge is small. The toner includes toner particles each having a surface layer containing an organosilicon polymer, in which: the organosilicon polymer includes a siloxane-based polymer having partial structures represented by the following formulae (1) and (2); and in a chart obtained by 29Si-NMR measurement of a tetrahydrofuran-insoluble matter of the toner particles, an area RT3 of a peak assigned to the partial structure represented by the following formula (1) and an area RfT3 of a peak assigned to the partial structure represented by the following formula (2) satisfy the following formula (3). 0.300>(RfT3/RT3)?0.
    Type: Grant
    Filed: January 25, 2017
    Date of Patent: February 20, 2018
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Sara Yoshida, Katsuyuki Nonaka, Koji Abe, Toshihiko Katakura, Akane Masumoto, Maho Tanaka
  • Patent number: 9851650
    Abstract: A toner contains a styrene acrylic resin, a block polymer, and an organosilicon polymer, in which the organosilicon polymer has a specific partial structure, the block polymer has a polyester segment and a vinyl polymer segment, the melting point is 55° C. or more and 90° C. or less, the mass ratio of the polyester segment to the vinyl polymer segment is 40/60 to 80/20, and the polyester segment has a specific unit.
    Type: Grant
    Filed: May 4, 2016
    Date of Patent: December 26, 2017
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naoya Isono, Yoshihiro Nakagawa, Harumi Takada, Reo Tagawa, Shiro Kuroki, Sara Yoshida
  • Patent number: 9733583
    Abstract: Provided is a toner, including toner particle having surface layer, in which: the surface layer includes organosilicon polymer which has a partial structure represented by formula (1); in 29Si-NMR measurement of tetrahydrofuran-insoluble matter of toner particle, a ratio of a peak area for the partial structure represented by formula (1) to a total peak area for the organosilicon polymer is 5.0% or more; in X-ray photoelectron spectroscopic analysis of a surface of toner particle, a ratio of a density of a silicon atom dSi in the surface of toner particle is 1.0 to 28.6 atom %; and in a roughness curve of toner particle measured by using a scanning probe microscope: an arithmetic average roughness Ra is 10 to 300 nm; ?Ra/Ra is 0.60 or less; an average length RSm of a roughness curve element is 20 to 500 nm; and ?RSm/RSm is 0.60 or less.
    Type: Grant
    Filed: April 1, 2016
    Date of Patent: August 15, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Shiro Kuroki, Katsuyuki Nonaka, Koji Abe, Toshihiko Katakura, Tsuneyoshi Tominaga, Sara Yoshida