Patents by Inventor Yayoi Tazawa

Yayoi Tazawa 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: 7943281
    Abstract: In a black toner having at least a binder resin and an iron-titanium composite oxide as a colorant; the iron-titanium composite oxide is contained in a specific amount; the black toner has a specific weight average particle diameter and a specific saturation magnetization; the black toner has, in X-ray diffraction thereof, a maximum peak at 2?=from 32.5 to 33.1 degrees, having a half width of 0.25 degree or less. The black toner has, in a proportion of less than 30% by number, an iron-titanium composite oxide having, in a sectional photograph of the toner, a maximum frequency of linearity within the range where the linearity is smaller than 2.4 and having a linearity of 3.0 or more, in regard to the number frequency distribution of the linearity of the iron-titanium composite oxide.
    Type: Grant
    Filed: April 14, 2006
    Date of Patent: May 17, 2011
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takaaki Kaya, Yasukazu Ayaki, Shigeto Tamura, Yayoi Tazawa, Ryoichi Fujita, Yuichi Yajima
  • Publication number: 20090011353
    Abstract: In a black toner having at least a binder resin and an iron-titanium composite oxide as a colorant; the iron-titanium composite oxide is contained in a specific amount; the black toner has a specific weight average particle diameter and a specific saturation magnetization; the black toner has, in X-ray diffraction thereof, a maximum peak at 2?=from 32.5 to 33.1 degrees, having a half width of 0.25 degree or less. The black toner has, in a proportion of less than 30% by number, an iron-titanium composite oxide having, in a sectional photograph of the toner, a maximum frequency of linearity within the range where the linearity is smaller than 2.4 and having a linearity of 3.0 or more, in regard to the number frequency distribution of the linearity of the iron-titanium composite oxide.
    Type: Application
    Filed: April 14, 2006
    Publication date: January 8, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Takaaki Kaya, Yasukazu Ayaki, Shigeto Tamura, Yayoi Tazawa, Ryoichi Fujita, Yuichi Yajima
  • Patent number: 7049039
    Abstract: A coloring agent for use in toners which comprises coloring particles modified with a surface modifier having in one molecule a hydrophilic moiety, a hydrophobic moiety, and a reactive moiety between the hydrophilic moiety and the hydrophobic moiety. Also disclosed is a toner comprising toner particles containing at least a binder resin and a coloring agent comprising the above surface-modified coloring particles.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: May 23, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yayoi Tazawa, Yasukazu Ayaki
  • Patent number: 6808855
    Abstract: A toner production process comprising the step of polymerizing a polymerizable monomer in the presence of (i) base particles containing at least a binder resin and (ii) a polymerization initiator. The polymerization initiator has in one molecule a hydrophilic moiety and a hydrophobic moiety and a reactive moiety between them, and the base particles are enlarged and/or surface-modified upon polymerization of the polymerizable monomer. Also disclosed is a toner having a circularity of from 0.92 to 1.0, which is produced by this process.
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: October 26, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasukazu Ayaki, Hitoshi Itabashi, Yayoi Tazawa
  • Patent number: 6566028
    Abstract: A toner is comprised of toner particles composed of at least a binder resin and a clorant, wherein the toner particles each have a coating layer formed on their surfaces in a state of particulate matters being stuck to one another. The particulate matters contains at least a silicon compound.
    Type: Grant
    Filed: July 16, 2001
    Date of Patent: May 20, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yayoi Tazawa, Takeshi Ikeda, Yoshinobu Baba, Hitoshi Itabashi, Yuzo Tokunaga, Yasukazu Ayaki
  • Publication number: 20030073020
    Abstract: A toner production process comprising the step of polymerizing a polymerizable monomer in the presence of (i) base particles containing at least a binder resin and (ii) a polymerization initiator. The polymerization initiator has in one molecule a hydrophilic moiety and a hydrophobic moiety and a reactive moiety between them, and the base particles are enlarged and/or surface-modified upon polymerization of the polymerizable monomer. Also disclosed is a toner having a circularity of from 0.92 to 1.0, which is produced by this process.
    Type: Application
    Filed: May 23, 2002
    Publication date: April 17, 2003
    Inventors: Yasukazu Ayaki, Hitoshi Itabashi, Yayoi Tazawa
  • Publication number: 20030027071
    Abstract: A coloring agent for use in toners which comprises coloring particles modified with a surface modifier having in one molecule a hydrophilic moiety, a hydrophobic moiety, and a reactive moiety between the hydrophilic moiety and the hydrophobic moiety. Also disclosed is a toner comprising toner particles containing at least a binder resin and a coloring agent comprising the above surface-modified coloring particles.
    Type: Application
    Filed: May 21, 2002
    Publication date: February 6, 2003
    Inventors: Yayoi Tazawa, Yasukazu Ayaki
  • Publication number: 20020197551
    Abstract: A toner is comprised of toner particles composed of at least a binder resin and a clorant, wherein the toner particles each have a coating layer formed on their surfaces in a state of particulate matters being stuck to one another. The particulate matters contains at least a silicon compound.
    Type: Application
    Filed: July 16, 2001
    Publication date: December 26, 2002
    Inventors: Yayoi Tazawa, Takeshi Ikeda, Yoshinobu Baba, Hitoshi Itabashi, Yuzo Tokunaga, Yasukazu Ayaki
  • Patent number: 6358658
    Abstract: A toner is comprised of toner particles composed of at least a binder resin and a clorant, wherein the toner particles each have a coating layer formed on their surfaces in a state of particulate matters being stuck to one another. The particulate matters contains at least a silicon compound.
    Type: Grant
    Filed: November 18, 1999
    Date of Patent: March 19, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yayoi Tazawa, Takeshi Ikeda, Yoshinobu Baba, Hitoshi Itabashi, Yuzo Tokunaga, Yasukazu Ayaki
  • Patent number: 6106990
    Abstract: A process for producing toner particles is conducted by:preparing toner precursor particles containing at least binder resin and coloring agent; andspherizing the toner precursor particles to obtain toner particles;wherein spherizing steps include;(1) dispersing the toner precursor particles in an aqueous medium containing a dispersant, thereby preparing a disperse system (a);(2) dispersing oil droplet particles containing a softening agent into an aqueous medium, thereby preparing a disperse system (b);(3) preparing a mixed disperse system (c) by adding the disperse system (a) to the disperse system (b), and causing the softening agent to be absorbed by the toner precursor particles in the mixed disperse system (c); and(4) removing the softening agent from the toner precursor particles.
    Type: Grant
    Filed: July 29, 1999
    Date of Patent: August 22, 2000
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yayoi Tazawa, Yoshinobu Baba, Hitoshi Itabashi, Yuzo Tokunaga, Yasukazu Ayaki