Patents by Inventor Ryota Kashiwabara

Ryota Kashiwabara 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: 20030044708
    Abstract: A toner is formed of toner particles each comprising at least a binder resin, a colorant and a wax, and inorganic fine powder. The toner is characterized by (a) containing a sulfur-containing polymer, and (b) showing dielectric loss tangent (tan&dgr;) values at 100 kHz assuming a maximum of 2.5×10−2 to 8×10−2 in a temperature range of 100 to 130° C. Because of the combination of the features (a) and (b), the toner can exhibit a good combination of developing performances and fixing performances.
    Type: Application
    Filed: March 15, 2002
    Publication date: March 6, 2003
    Inventors: Satoshi Matsunaga, Junko Yoshikawa, Ryota Kashiwabara
  • Patent number: 6447970
    Abstract: A toner contains at least a binder resin, a colorant, a wax and an aluminum compound, wherein the binder resin has an acid value of 1 to 40 mgKOH/g; the binder resin contains 2% to 50% by weight of tetrahydrofuran (THF) based on the weight of the binder resin; a tetrahydrofuran-soluble matter of the binder resin has a main peak in a molecular weight range of from 2,000 to 30,000 in a chromatogram by gel permeation chromatography (GPC); and the aluminum compound is a specific aluminum compound of substituted or unsubstituted benzilic acid.
    Type: Grant
    Filed: June 7, 2000
    Date of Patent: September 10, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventors: Satoshi Matsunaga, Manabu Ohno, Koji Inaba, Satoshi Handa, Ryota Kashiwabara
  • Publication number: 20020098433
    Abstract: A toner exhibiting good balance of low-temperature fixability, an anti-offset characteristic and a developing performance in continuous image formation is formed of at least a binder resin, a colorant and a wax. The toner exhibits a dielectric loss tangent showing a maximum of 6.0×10−2 to 10.0×10−2 in a temperature range of 90 to 125° C. The toner provides a DSC curve showing at least one heat-absorption peak or shoulder in a temperature range of 85 to 140° C. on temperature increase according to differential scanning calorimetry (DSC). The binder resin comprises a hybrid resin having a vinyl polymer unit and a polyester unit.
    Type: Application
    Filed: October 29, 2001
    Publication date: July 25, 2002
    Inventors: Satoshi Matsunaga, Yuichi Mizoh, Junko Yoshikawa, Ryota Kashiwabara
  • Publication number: 20020055053
    Abstract: A toner showing quick chargeability and stable chargeability in a high humidity environment is provided by a combination of a specific polyester binder resin and a specific azo iron compound. The polyester binder resin has an acid value (Av) of 0.5 to 30 mgKOH/g and a hydroxyl value (OHv) of 1 to 50 mgKOH/g giving a ratio (Av/OHv) therebetween satisfying: 0.05≦Av/OHv≦2.0. The azo iron compound is preferably an iron complex (salt) including as a ligand a mono-azo compound formed by diazo coupling between a 2-aminophenol (derivative) and an alkyl-substituted naphthol (derivative).
    Type: Application
    Filed: September 6, 2001
    Publication date: May 9, 2002
    Inventors: Takashige Kasuya, Hirohide Tanikawa, Hiroshi Yusa, Yoshihiro Ogawa, Katsuhisa Yamazaki, Ryota Kashiwabara
  • Publication number: 20020045120
    Abstract: A toner containing toner particles and an inorganic fine powder; the toner particles containing at least a binder resin, a colorant, a sulfur-containing resin, and a wax; the binder resin containing a hybrid resin component containing a vinyl type polymer unit and a polyester unit, and the sulfur-containing resin being a resin selected from the group consisting of sulfur-containing polymers and sulfur-containing copolymers
    Type: Application
    Filed: July 27, 2001
    Publication date: April 18, 2002
    Inventors: Junko Yoshikawa, Yuichi Mizoo, Satoshi Matsunaga, Tadashi Dojo, Nene Shibayama, Ryota Kashiwabara