Patents by Inventor Hironori Minagawa

Hironori Minagawa 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: 11762307
    Abstract: A toner having a toner particle containing a binder resin and a styrene-acrylic resin, the toner being characterized in that the styrene-acrylic resin is a graft polymer having an aliphatic hydrocarbon compound segment and a styrene-acrylic segment, the styrene-acrylic segment has a specific monomer unit, the melting point of the styrene-acrylic segment is from 30° C. to 80° C., and when the toner is measured using a FT-IR ATR method, the intensity assigned to the styrene-acrylic resin and the intensity assigned to the binder resin satisfy a specific relationship.
    Type: Grant
    Filed: August 7, 2020
    Date of Patent: September 19, 2023
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Junichi Tamura, Takaho Shibata, Ryuji Murayama, Kenta Mitsuiki, Megumi Shino, Hironori Minagawa
  • Publication number: 20220269189
    Abstract: A magnetic carrier comprises a magnetic carrier core and a coating resin layer coating a surface of the magnetic carrier core. The coating resin layer contains resin A and resin B at contents of 1% to 50% by mass and 50% to 90% by mass, respectively, based on resin components of the coating resin layer. The resin A has a first partial structure and a second partial structure, while the resin B has a third partial structure and a fourth partial structure. The mass X of the resin A, the total mass Ma of the first partial structure, and the total mass Mb of the second partial structure satisfy 0.50?(Ma+Mb)/X?1.00 and 0.10?a/b?30.0, and the SP value of the first partial structure SPa1 and the SP value of the third partial structure SPb3 satisfy 0?|SPa1—SPb3|?10.0.
    Type: Application
    Filed: February 7, 2022
    Publication date: August 25, 2022
    Inventors: Yuu Nishimura, Yuzo Tokunaga, Nobuyoshi Sugahara, Hironori Minagawa, Nobuhiro Yoshida
  • Publication number: 20220236659
    Abstract: A magnetic carrier, which is suppressed from causing the loss and wear of a magnetic carrier coating resin even when used for a long time period, and achieves a stable image density and a reduction in toner scattering. In the magnetic carrier, the resin coating layer contains a resin A having a fluorine polymer moiety, the resin coating layer has an average thickness of 50 nm or more, a ratio F(x) (atomic %) of a fluorine atom detected at a position at a depth of x nm from a surface of a magnetic carrier particle by X-ray photoelectron spectroscopy satisfies formula (1) and formula (2), and when x represents an integer of 0 or more and 20 or less, F(x) satisfies formula (3): 5.0?F(0)?15??(1) F(20)?5.0??(2) |F(x+1)?F(x)|?7.5??(3).
    Type: Application
    Filed: January 21, 2022
    Publication date: July 28, 2022
    Inventors: Nobuhiro Yoshida, Hironori Minagawa, Yuzo Tokunaga, Nobuyoshi Sugahara, Yuu Nishimura
  • Publication number: 20220236660
    Abstract: A magnetic carrier including: a magnetic core; and a coating resin that coats a surface of the magnetic core, wherein the resin coating layer has a thickness of 50 nm or more, a coating resin, which forms the resin coating layer, contains a resin S having an organosilicon polymer moiety, and when a surface and a position at a depth of 20 nm from the surface of the magnetic carrier are analyzed by X-ray photoelectron spectroscopy, an amount of silicon element as determined by the analysis has a ratio within a specific range at respective positions.
    Type: Application
    Filed: January 21, 2022
    Publication date: July 28, 2022
    Inventors: Ryuji Murayama, Hironori Minagawa, Yuto Onozaki, Nobuhiro Yoshida
  • Publication number: 20220236658
    Abstract: A magnetic carrier includes a magnetic core and a coating resin that covers a surface of the magnetic core. The coating resin includes a resin A and a resin B. A content of the resin A is 1 to 50% by mass, and a content of the resin B is 50 to 99% by mass, with respect to the coating resin. The resin A has a particular unit Y1 and a particular unit Y2, and the resin B contains 0.1% by mass or less of the particular unit Y2. When a mass of the resin A is represented by X, a mass of the unit Y1 is represented by Ma, and a mass of the unit Y2 is represented by Mb, 0.90?(Ma+Mb)/X?1.00 and 1.00?Ma/Mb?30.0 are satisfied, and also 0?|SPa?SPb|?2.0 is satisfied.
    Type: Application
    Filed: January 24, 2022
    Publication date: July 28, 2022
    Inventors: Ryuji Murayama, Yuto Onozaki, Nobuhiro Yoshida, Hironori Minagawa
  • Publication number: 20220236657
    Abstract: A magnetic carrier including a magnetic core and a coating resin configured to coat the surface of the magnetic core. The coating resin contains a graft resin A and a graft resin B. The coating resin (i) contains 1.0 mass % or more and 50.0 mass % or less of the graft resin A, and (ii) contains 50.0 mass % or more and 99.0 mass % or less of the graft resin B. The graft resin A has a unit Y1 represented by formula (1) and a unit Y2 represented by formula (2). The graft resin B (i) is a comb-shaped polymer having, as a branch, at least one moiety selected from, for example, a styrene-based polymer moiety and a (meth)acrylate-based polymer moiety, and (ii) contains the polysiloxane structure moiety at a content of 0.1 mass % or less.
    Type: Application
    Filed: January 26, 2022
    Publication date: July 28, 2022
    Inventors: Yuto Onozaki, Ryuji Murayama, Nobuhiro Yoshida, Hironori Minagawa
  • Publication number: 20210389688
    Abstract: A negative-charging toner comprising a toner particle comprising a binder resin and an organic-inorganic composite fine particle comprising resin fine particles and inorganic fine particles A, wherein the organic-inorganic composite fine particle is negative charging, the organic-inorganic composite fine particle has a structure in which at least a part of the inorganic fine particle A is embedded in the resin fine particle, a number average particle diameter Db of the organic-inorganic composite fine particle is 50 to 350 nm, and a plurality of convex portions derived from the inorganic fine particles A are present on the surface of the organic-inorganic composite fine particle.
    Type: Application
    Filed: June 2, 2021
    Publication date: December 16, 2021
    Inventors: Takaho Shibata, Ryuji Murayama, Ryuichiro Matsuo, Yuto Onozaki, Kenta Mitsuiki, Megumi Shino, Hironori Minagawa
  • Patent number: 11131938
    Abstract: A toner comprises a toner particle including a binder resin, and inorganic fine particles A and silica particles B, wherein the inorganic fine particle A has a rectangular parallelepiped shape; an amount of the inorganic fine particles A is 0.3 to 3.0 mass parts per 100 mass parts of the toner particles; a number average particle diameter of the silica particles B is 80 to 200 nm; a fixing ratio of the inorganic fine particle A is 25% to 70%; where a separation amount of the inorganic fine particles A is denoted by YA (mg), and a separation amount of the silica particles is denoted by YB (mg), YA is 3.00 to 18.0, YA and YB satisfy the following formula, YA/YB>0.75, and a surface potential difference C in a rubbing test using the inorganic fine particle A and the binder resin is ?70 V to +70 V.
    Type: Grant
    Filed: August 13, 2019
    Date of Patent: September 28, 2021
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Ryuji Murayama, Takaho Shibata, Junichi Tamura, Kenta Mitsuiki, Megumi Shino, Hironori Minagawa
  • Publication number: 20210055668
    Abstract: A toner having a toner particle containing a binder resin and a styrene-acrylic resin, the toner being characterized in that the styrene-acrylic resin is a graft polymer having an aliphatic hydrocarbon compound segment and a styrene-acrylic segment, the styrene-acrylic segment has a specific monomer unit, the melting point of the styrene-acrylic segment is from 30° C. to 80° C., and when the toner is measured using a FT-IR ATR method, the intensity assigned to the styrene-acrylic resin and the intensity assigned to the binder resin satisfy a specific relationship.
    Type: Application
    Filed: August 7, 2020
    Publication date: February 25, 2021
    Inventors: Junichi Tamura, Takaho Shibata, Ryuji Murayama, Kenta Mitsuiki, Megumi Shino, Hironori Minagawa
  • Patent number: 10877391
    Abstract: A magnetic carrier including a magnetic carrier particle having a magnetic carrier core and a resin coating layer formed on a surface of the magnetic carrier core, wherein the resin coating layer includes a resin component including a resin A and a resin B, the resin A is a copolymer of monomers including (a) a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group and (b) a specific macromonomer, the resin B is a copolymer of monomers including (c) a styrene-based monomer and (d) a specific (meth)acrylic acid ester monomer, and in a molecular weight distribution of a THF soluble component of the resin component contained in the resin coating layer, a peak derived from the resin B is present in a molecular weight range of from 1000 to 9500.
    Type: Grant
    Filed: August 5, 2019
    Date of Patent: December 29, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Ryuichiro Matsuo, Nobuyoshi Sugahara, Hironori Minagawa, Wakashi Iida
  • Patent number: 10859936
    Abstract: A magnetic carrier comprising a magnetic carrier core and a resin coating layer formed on the surface of the magnetic carrier core, wherein the resin coating layer includes a polymer having a structure represented by the following formula (1), and a content ratio of the structure represented by the formula (1) is from 5% by mass to 95% by mass based on a resin component of the resin coating layer, wherein, R1 is H or CH3, and X is a structure represented by the following formula (2): —(CmH2m)—R2—(CnH2n)—OH??(2) wherein, R2 is a hydrocarbon group being a cyclic structure having 4 to 8 carbon atoms, and m and n are integers of 0 to 4.
    Type: Grant
    Filed: September 16, 2019
    Date of Patent: December 8, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Nobuyoshi Sugahara, Ryuichiro Matsuo, Hironori Minagawa, Wakashi Iida
  • Patent number: 10852653
    Abstract: A magnetic carrier includes a magnetic carrier particle including a magnetic carrier core particle having an amino group on a surface thereof and a resin covering layer disposed on the surface of the magnetic carrier core particle, in which the resin covering layer contains a vinyl-based copolymer and a trialkoxyalkylsilane.
    Type: Grant
    Filed: August 22, 2019
    Date of Patent: December 1, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Ryuichiro Matsuo, Nobuyoshi Sugahara, Hironori Minagawa, Wakashi Iida
  • Patent number: 10838317
    Abstract: A magnetic carrier including a magnetic carrier particle having a magnetic carrier core and a resin coating layer formed on a surface of the magnetic carrier core, wherein the resin coating layer includes a resin component including a resin A and a resin B, the resin A is a copolymer of monomers including (a) a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group and (b) a specific macromonomer, the resin B is a copolymer of monomers including (c) a styrene-based monomer and (d) a specific (meth)acrylic acid ester monomer, and based on the resin components of the resin coating layer, the amount of the resin A is from 20% by mass to 99% by mass, and the amount of the resin B is from 1% by mass to 80% by mass.
    Type: Grant
    Filed: July 30, 2019
    Date of Patent: November 17, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Nobuyoshi Sugahara, Ryuichiro Matsuo, Hironori Minagawa, Wakashi Iida
  • Publication number: 20200103777
    Abstract: A magnetic carrier comprising a magnetic carrier core and a resin coating layer formed on the surface of the magnetic carrier core, wherein the resin coating layer includes a polymer having a structure represented by the following formula (1), and a content ratio of the structure represented by the formula (1) is from 5% by mass to 95% by mass based on a resin component of the resin coating layer, wherein, R1 is H or CH3, and X is a structure represented by the following formula (2): —(CmH2m)—R2—(CnH2n)—OH ??(2) wherein, R2 is a hydrocarbon group being a cyclic structure having 4 to 8 carbon atoms, and m and n are integers of 0 to 4.
    Type: Application
    Filed: September 16, 2019
    Publication date: April 2, 2020
    Inventors: Nobuyoshi Sugahara, Ryuichiro Matsuo, Hironori Minagawa, Wakashi lida
  • Publication number: 20200073270
    Abstract: A magnetic carrier includes a magnetic carrier particle including a magnetic carrier core particle having an amino group on a surface thereof and a resin covering layer disposed on the surface of the magnetic carrier core particle, in which the resin covering layer contains a vinyl-based copolymer and a trialkoxyalkylsilane.
    Type: Application
    Filed: August 22, 2019
    Publication date: March 5, 2020
    Inventors: Ryuichiro Matsuo, Nobuyoshi Sugahara, Hironori Minagawa, Wakashi Iida
  • Publication number: 20200064751
    Abstract: A toner comprises a toner particle including a binder resin, and inorganic fine particles A and silica particles B, wherein the inorganic fine particle A has a rectangular parallelepiped shape; an amount of the inorganic fine particles A is 0.3 to 3.0 mass parts per 100 mass parts of the toner particles; a number average particle diameter of the silica particles B is 80 to 200 nm; a fixing ratio of the inorganic fine particle A is 25% to 70%; where a separation amount of the inorganic fine particles A is denoted by YA (mg), and a separation amount of the silica particles is denoted by YB (mg), YA is 3.00 to 18.0, YA and YB satisfy the following formula, YA/YB>0.75, and a surface potential difference C in a rubbing test using the inorganic fine particle A and the binder resin is ?70 V to +70 V.
    Type: Application
    Filed: August 13, 2019
    Publication date: February 27, 2020
    Inventors: Ryuji Murayama, Takaho Shibata, Junichi Tamura, Kenta Mitsuiki, Megumi Shino, Hironori Minagawa
  • Publication number: 20200050123
    Abstract: A magnetic carrier including a magnetic carrier particle having a magnetic carrier core and a resin coating layer formed on a surface of the magnetic carrier core, wherein the resin coating layer includes a resin component including a resin A and a resin B, the resin A is a copolymer of monomers including (a) a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group and (b) a specific macromonomer, the resin B is a copolymer of monomers including (c) a styrene-based monomer and (d) a specific (meth)acrylic acid ester monomer, and based on the resin components of the resin coating layer, the amount of the resin A is from 20% by mass to 99% by mass, and the amount of the resin B is from 1% by mass to 80% by mass.
    Type: Application
    Filed: July 30, 2019
    Publication date: February 13, 2020
    Inventors: Nobuyoshi Sugahara, Ryuichiro Matsuo, Hironori Minagawa, Wakashi Iida
  • Publication number: 20200050124
    Abstract: A magnetic carrier including a magnetic carrier particle having a magnetic carrier core and a resin coating layer formed on a surface of the magnetic carrier core, wherein the resin coating layer includes a resin component including a resin A and a resin B, the resin A is a copolymer of monomers including (a) a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group and (b) a specific macromonomer, the resin B is a copolymer of monomers including (c) a styrene-based monomer and (d) a specific (meth)acrylic acid ester monomer, and in a molecular weight distribution of a THF soluble component of the resin component contained in the resin coating layer, a peak derived from the resin B is present in a molecular weight range of from 1000 to 9500.
    Type: Application
    Filed: August 5, 2019
    Publication date: February 13, 2020
    Inventors: Ryuichiro Matsuo, Nobuyoshi Sugahara, Hironori Minagawa, Wakashi Iida
  • Patent number: 10409188
    Abstract: Provided is a magnetic carrier comprising a magnetic carrier particle having a magnetic body-dispersed resin carrier core material and a resin coating layer; the core material includes magnetic particles A and B having number average primary particle diameter of ra and rb (?m), respectively, satisfying ra?rb; the particles A each include an oxide of at least one nonferrous metal of Mn, Al, Mg, Ti, and Ni; and an iron oxide; M1 represents total content of the nonferrous metal and F1 represents content of an iron of the magnetic carrier particle measured by XRF diffraction, M1/F1 is 0.010 to 0.100; M2 represents total content of the nonferrous metal and F2 represents content of an iron is F2 of the magnetic carrier particle measured by XPS, M2/F2 is 1.0 to 10.0.
    Type: Grant
    Filed: February 6, 2018
    Date of Patent: September 10, 2019
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Nobuyoshi Sugahara, Hironori Minagawa, Wakashi Iida
  • Publication number: 20190204764
    Abstract: A toner container detachably mountable to an image forming apparatus, includes a main body for containing toner: a sealing portion for sealing the toner discharge opening; locking projections for snap-fitting engagement with holes provided in a cylindrical member of an image forming apparatus, wherein the projections receive from the cylindrical member unsealing forces for unsealing the toner discharge opening by a relative movement between the sealing portion and the toner container, wherein a number of the locking projections is larger than a number of ribs provided between the holes of the cylindrical member.
    Type: Application
    Filed: February 14, 2019
    Publication date: July 4, 2019
    Inventors: Yusuke Yamada, Yutaka Ban, Katsuya Murakami, Fumio Tazawa, Hironori Minagawa