Patents by Inventor Yasuhiro Ichikawa

Yasuhiro Ichikawa 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).

  • Publication number: 20020037466
    Abstract: A magenta toner containing at least a binder resin and a colorant; the magenta toner having a storage elastic modulus at a temperature of 80° C., G′80, in the range of from 1×106 dN/m2 to 1×108 dN/m2 and a storage elastic modulus at a temperature of from 120° C. to 180° C., G′120-180, in the range of from 2×103 dN/m2 to 1×106 dN/m2, and containing at least a compound selected from the group consisting of compounds represented by the following Formulas (1) and (2) and a compound represented by the following Formula (3).
    Type: Application
    Filed: July 10, 2001
    Publication date: March 28, 2002
    Inventors: Makoto Kanbayashi, Takaaki Kotaki, Katsumi Kondo, Yasuhiro Ichikawa, Takaaki Kaya, Wakashi Iida, Takayuki Itakura
  • Patent number: 6187490
    Abstract: A two-component developer suitable for electrophotography is formed of a toner and a resin-coated carrier. The resin-coated carrier is formed of carrier core particles and 0.01-2.0 wt. % based on the carrier core particles of a resin coating layer coating the carrier core particles. The resin-coated carrier has an average particle size of 25-55 &mgr;m and the carrier core particles comprise a ferrite component represented by formula (I) below: (Fe2O3)a(MnO)b(MgO)c(A)d  (I), wherein A represents a mixture of SrO, CaO and Al2O3, and a, b, c and d are numbers representing mol fractions of associated components and satisfying: 0.4<a<0.6, 0.35<b<0.45, 0.07<c<0.12, 0.005<d<0.015, and a+b+c+d≦1. Because of the specific composition, the carrier core particles are provided with a smooth surface, which is reflected into a surface smoothness of the resin-coated carrier even after coated with a thin resin coating layer.
    Type: Grant
    Filed: March 15, 2000
    Date of Patent: February 13, 2001
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaaki Taya, Takaaki Kohtaki, Yasuhiro Ichikawa
  • Patent number: 6146801
    Abstract: A resin-coated carrier for two component type developers, with carrier particles having a carrier core material and a coat layer which covers the surface of the carrier core material. The resin-coated carrier has a 50% particle diameter C (D.sub.50) from 25 .mu.m to 70 .mu.m, contains carrier particles smaller than 22 .mu.m in particle diameter in an amount from 0.1% by number to 20% by number and contains carrier particles of 62 .mu.m or larger in particle diameter in an amount from 2% by number to 35% by number. The carrier core material has a BET specific surface area SW1 where the coat layer has been removed and the resin-coated carrier has a BET specific surface area SW2. The SW1 and SW2 satisfy the following expression (I), and the resin-coated carrier satisfies a shape factor SF-1 of the following expression (II) and a shape factor SF-2 of the following expression (III):80.ltoreq.SW1-SW2.ltoreq.650(cm.sup.2 /g) (I)110.ltoreq.SF-1.ltoreq.160 (II)105.ltoreq.SF-2.ltoreq.
    Type: Grant
    Filed: September 29, 1999
    Date of Patent: November 14, 2000
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuhiro Ichikawa, Tetsuya Ida
  • Patent number: 5733702
    Abstract: An image forming method is conducted by forming a toner image on a latent image bearing member containing an organic photoconductive material. The latent image bearing member includes a photosensitive layer containing an organic photoconductive material and a protective layer which contains fluorine-containing resin particles in an amount from 5% by weight to 40% by weight. The toner contains toner particles and external additives. The external additives include titanium oxide particles having a weight average particle diameter from 0.01 .mu.m to 0.2 .mu.m having been subjected to hydrophobic treatment, organic resin particles having a weight average particle diameter from 0.02 .mu.m to 0.5 .mu.m, and inorganic compound particles having a weight average particle diameter from 0.5 .mu.m to 2.5 m.The inorganic compound particles may be specific titanates, oxides or carbonate.
    Type: Grant
    Filed: April 5, 1995
    Date of Patent: March 31, 1998
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kenji Okado, Toshiyuki Ugai, Ryoichi Fujita, Tsuyoshi Takiguchi, Yasuhiro Ichikawa
  • Patent number: 5670288
    Abstract: A carrier for electrophotography has carrier particles. The carrier has a 50% average particle diameter (D.sub.50) of from 15 .mu.m to 45 .mu.m and contains from 1% to 20% of carrier particles with a size smaller than 22 .mu.m, not more than 3% of carrier particles with a size smaller than 16 .mu.m, from 2% to 15% of carrier particles with a size of 62 .mu.m or larger, and not more than 2% of carrier particles with a size of 88 .mu.m or larger. The carrier has a specific surface area S.sub.1 as measured by an air-permeability method and a specific surface area S.sub.2 as calculated by the following expression:S.sub.2 =(6/.rho..multidot.D.sub.50).times.10.sup.4wherein .rho. is a specific gravity of carrier; satisfying the following condition:1.2 .ltoreq.S.sub.1 /S.sub.2 .ltoreq.2.0.
    Type: Grant
    Filed: February 12, 1996
    Date of Patent: September 23, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kenji Okado, Toshiyuki Ugai, Ryoichi Fujita, Makoto Kanbayashi, Tsuyoshi Takiguchi, Yasuhiro Ichikawa, Wakashi Iida
  • Patent number: 5637432
    Abstract: The present invention provides a toner for developing an electrostatic image, comprising toner particles and external additives, wherein;said external additives comprise (A) titanium oxide particles having a weight average particle diameter of from 0.01 .mu.m to 0.2 .mu.m, having been subjected to hydrophobic treatment, (B) organic resin particles having a weight average particle diameter of from 0.02 .mu.m to 0.5 .mu.m and (C) an inorganic compound having a weight average particle diameter of from 0.5 .mu.m to 2.5 .mu.m; said external additives being added in an amount satisfying the relationship:(A):(B)=2:1 to 10:1(A):(C)=1:1 to 5:1; andsaid toner contains toner particles having a particle diameter of from 2 .mu.m to 5 .mu.m in an amount of from 15% by number to 40% by number.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: June 10, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kenji Okado, Toshiyuki Ugai, Ryoichi Fujita, Tsuyoshi Takiguchi, Yasuhiro Ichikawa
  • Patent number: 5512402
    Abstract: A carrier for electrophotography has carrier particles. The carrier has a 50% average particle diameter (D.sub.50) of from 15 .mu.m to 45 .mu.m and contains from 1% to 20% of carrier particles with a size smaller than 22 .mu.m, not more than 3% of carrier particles with a size smaller than 16 .mu.m, from 2% to 15% of carrier particles with a size of 62 .mu.m or larger, and not more than 2% of carrier particles with a size of 88 .mu.m or larger. The carrier has a specific surface area S.sub.1 as measured by an air-permeability method and a specific surface area S.sub.2 as calculated by the following expression:S.sub.2 =(6/.rho..D.sub.50).times.10.sup.4wherein .rho. is a specific gravity of carrier; satisfying the following condition:1.2.ltoreq.S.sub.1 /S.sub.2 .ltoreq.2.0.
    Type: Grant
    Filed: May 19, 1994
    Date of Patent: April 30, 1996
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kenji Okado, Toshiyuki Ugai, Ryoichi Fujita, Makoto Kanbayashi, Tsuyoshi Takiguchi, Yasuhiro Ichikawa, Wakashi Iida
  • Patent number: 5456916
    Abstract: The present invention provides a resin molding composition for preventing gnawing damage by the animal, a microcapsule filled with a capsaicine compound, and a process for producing the capsaicine compound and the microcapsule.
    Type: Grant
    Filed: February 22, 1994
    Date of Patent: October 10, 1995
    Assignee: Nippon Kayaku Kabushiki Kaisha
    Inventors: Mitsuo Kurata, Yasuhiro Ichikawa, Mika Toya, Iwao Takahashi, Yoshinobu Okui, Shoichi Kato, Takeshi Nishitani
  • Patent number: 5322862
    Abstract: The present invention provides a resin molding composition for preventing gnawing damage by the animal, a microcapsule filled with a capsaicine compound, and a process for producing the capsaicine compound and the microcapsule.
    Type: Grant
    Filed: August 17, 1992
    Date of Patent: June 21, 1994
    Assignee: Nippon Kayaku Kabushiki Kaisha
    Inventors: Mitsuo Kurata, Yasuhiro Ichikawa, Mika Toya, Iwao Takahashi, Yoshinobu Okui