Patents by Inventor Rei Hijikawa

Rei Hijikawa 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: 11429032
    Abstract: A toner containing a toner particle that contains a binder resin including a polyester resin, and a polyolefin resin having —COOM that is a neutralized carboxy group with a monovalent metal ion M, wherein the polyolefin resin having —COOM is a polymer in which a vinyl polymer is bonded to a polyolefin, a content of a monomer unit containing —COOM in the polyolefin resin having —COOM is 1 to 20 mass %, and in a FT-IR spectrum obtained through measurement of a large particle size-side particle group and a small particle size-side particle group obtained by dividing the toner into two substantially equal parts, on a number basis, a ratio of the intensity of a maximum absorption peak in a range from 1545 cm?1 to 1555 cm?1 with respect to the intensity of a maximum absorption peak in a range from 1713 cm?1 to 1723 cm?1 exhibits a specific relationship.
    Type: Grant
    Filed: August 26, 2020
    Date of Patent: August 30, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Takaho Shibata, Yuichi Mizo, Koh Ishigami, Takakuni Kobori, Masaharu Miura, Takeshi Ohtsu, Yosuke Iwasaki, Daisuke Yamashita, Ryo Nakajima, Wakiko Katsumata, Hitoshi Sano, Kenta Mitsuiki, Rei Hijikawa
  • Publication number: 20220197164
    Abstract: A method for manufacturing a toner includes a pigment crushing step of kneading a pigment, a binder, and a grinding agent to obtain a pigment dispersion in which the grinding agent and the crushed pigment are dispersed in the binder; and a step of obtaining toner particles by a predetermined method using the pigment dispersion. The binder and the grinding agent are contained in the resulting toner particles.
    Type: Application
    Filed: December 8, 2021
    Publication date: June 23, 2022
    Inventors: Junichi Tamura, Kazuhisa Shirayama, Rei Hijikawa, Ryuji Okamura, Yuya Chimoto, Hisasuke Kajihara
  • Publication number: 20210063903
    Abstract: A toner containing a toner particle that contains a binder resin including a polyester resin, and a polyolefin resin having —COOM that is a neutralized carboxy group with a monovalent metal ion M, wherein the polyolefin resin having —COOM is a polymer in which a vinyl polymer is bonded to a polyolefin, a content of a monomer unit containing —COOM in the polyolefin resin having —COOM is 1 to 20 mass %, and in a FT-IR spectrum obtained through measurement of a large particle size-side particle group and a small particle size-side particle group obtained by dividing the toner into two substantially equal parts, on a number basis, a ratio of the intensity of a maximum absorption peak in a range from 1545 cm?1 to 1555 cm?1 with respect to the intensity of a maximum absorption peak in a range from 1713 cm?1 to 1723 cm?1 exhibits a specific relationship.
    Type: Application
    Filed: August 26, 2020
    Publication date: March 4, 2021
    Inventors: Takaho Shibata, Yuichi Mizo, Koh Ishigami, Takakuni Kobori, Masaharu Miura, Takeshi Ohtsu, Yosuke Iwasaki, Daisuke Yamashita, Ryo Nakajima, Wakiko Katsumata, Hitoshi Sano, Kenta Mitsuiki, Rei Hijikawa
  • Patent number: 10809640
    Abstract: A toner that is suppressed from deteriorating owing to its long-term use and can maintain high transferability. The toner includes: a toner particle containing an amorphous polyester serving as a binder resin and a polymer A; and inorganic fine particles, wherein the polymer A includes a graft copolymer of a polyolefin and a vinyl-based polymer unit having a carboxylate anion group, and a metal ion having a valence of 2 or more.
    Type: Grant
    Filed: August 26, 2019
    Date of Patent: October 20, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yosuke Iwasaki, Kenta Mitsuiki, Wakiko Katsumata, Takeshi Ohtsu, Masaharu Miura, Koh Ishigami, Takakuni Kobori, Takaho Shibata, Daisuke Yamashita, Hitoshi Sano, Ryo Nakajima, Rei Hijikawa, Yuichi Mizo
  • Patent number: 10642178
    Abstract: A toner comprising a toner particle including a binder resin and a crystalline polyester resin, wherein the binder resin is an amorphous polyester resin having a linear alkyl group at a molecular chain terminal; the crystalline polyester resin is a polycondensate of a diol and a dicarboxylic acid; the number of carbon atoms CaPES of the linear alkyl group, the number of carbon atoms COH of the diol, and the number of carbon atoms CAc of the dicarboxylic acid, excluding carbon that belongs to carboxyl groups, satisfy the following relationships; and a glass transition temperature of the toner as measured by a differential scanning calorimeter is from 40.0° C. to 55.0° C. 8?CaPES?20??(1) CAc/COH?3.5 and 0?|CAc?CaPES|?3??(2) COH/CAc?3.
    Type: Grant
    Filed: April 8, 2019
    Date of Patent: May 5, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Daisuke Yamashita, Yuichi Mizo, Koh Ishigami, Masaharu Miura, Takaho Shibata, Takeshi Ohtsu, Yosuke Iwasaki, Wakiko Katsumata, Hitoshi Sano, Kenta Mitsuiki, Takakuni Kobori, Rei Hijikawa
  • Publication number: 20200073264
    Abstract: A toner that is suppressed from deteriorating owing to its long-term use and can maintain high transferability. The toner includes: a toner particle containing an amorphous polyester serving as a binder resin and a polymer A; and inorganic fine particles, wherein the polymer A includes a graft copolymer of a polyolefin and a vinyl-based polymer unit having a carboxylate anion group, and a metal ion having a valence of 2 or more.
    Type: Application
    Filed: August 26, 2019
    Publication date: March 5, 2020
    Inventors: Yosuke Iwasaki, Kenta Mitsuiki, Wakiko Katsumata, Takeshi Ohtsu, Masaharu Miura, Koh Ishigami, Takakuni Kobori, Takaho Shibata, Daisuke Yamashita, Hitoshi Sano, Ryo Nakajima, Rei Hijikawa, Yuichi Mizo
  • Publication number: 20190339629
    Abstract: A toner comprising a toner particle including a binder resin and a crystalline polyester resin, wherein the binder resin is an amorphous polyester resin having a linear alkyl group at a molecular chain terminal; the crystalline polyester resin is a polycondensate of a diol and a dicarboxylic acid; the number of carbon atoms CaPES of the linear alkyl group, the number of carbon atoms COH of the diol, and the number of carbon atoms CAc of the dicarboxylic acid, excluding carbon that belongs to carboxyl groups, satisfy the following relationships; and a glass transition temperature of the toner as measured by a differential scanning calorimeter is from 40.0° C. to 55.0° C. 8?CaPES?20??(1) CAc/COH?3.5 and 0?|CAc?CaPES|?3??(2) COH/CAc?3.
    Type: Application
    Filed: April 8, 2019
    Publication date: November 7, 2019
    Inventors: Daisuke Yamashita, Yuichi Mizo, Koh Ishigami, Masaharu Miura, Takaho Shibata, Takeshi Ohtsu, Yosuke Iwasaki, Wakiko Katsumata, Hitoshi Sano, Kenta Mitsuiki, Takakuni Kobori, Rei Hijikawa