Patents by Inventor Daisuke Yoshiba

Daisuke Yoshiba 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: 7544455
    Abstract: A magnetic toner having magnetic toner particles each containing at least a binder resin and a magnetic iron oxide particle, in which: when a solution is prepared by dissolving the magnetic iron oxide particles in an acidic aqueous solution and an Fe element amount in a solution in which all the magnetic iron oxide particles are dissolved is defined as a total Fe element amount, a ratio X of the amount of Fe(2+) in a solution in which the magnetic iron oxide particles are dissolved to a state where 10 mass % of the total Fe element amount is present in the solution (solution having an Fe element-dissolving ratio of 10 mass %) to an Fe element amount in the solution having a specific Fe element-dissolving ratio; and the dielectric loss tangents of the magnetic toner measured at a temperature of 40° C. satisfy specific conditions.
    Type: Grant
    Filed: July 24, 2008
    Date of Patent: June 9, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Daisuke Yoshiba, Katsuhisa Yamazaki
  • Patent number: 7537877
    Abstract: A toner is provided which can stably provide a favorable density stability, line reproducibility and dot reproducibility even in high-speed copying machines, printers and the like which form high resolution latent images over a long period regardless of environmental conditions, and can provide the image quality adaptable to embedded pattern printing, QR code printing and the like. The present invention is characterized in that the toner which includes toner particles including at least a binder resin and a colorant, and a fine silica powder, has a volume median diameter (D50) of not less than 0.70 ?m and not more than 3.00 ?m, and a total pore volume of not more than 0.200 cm3/g, measured in the range of the pore diameter from not less than 1.7 nm and not more than 300.0 nm.
    Type: Grant
    Filed: November 29, 2007
    Date of Patent: May 26, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Daisuke Yoshiba, Katsuhisa Yamazaki, Syuhei Moribe, Junko Nishiyama, Shuichi Hiroko, Masami Fujimoto, Takashige Kasuya
  • Publication number: 20090123859
    Abstract: Provide is a toner including toner particles each containing at least a binder resin and a colorant, and an inorganic fine powder, in which the inorganic fine powder has a ratio (A/B) of a total pore volume A measured in a pore diameter range of from 1.9 nm or more and to 8.0 nm or less to a total pore volume B measured in a pore diameter range of from 1.9 nm or more and to 300.0 nm or less of from 0.20 or more and to 1.00 or less, and the total pore volume A is from 1.00×10?2 cm3/g or more and to 1.00 cm3/g or less.
    Type: Application
    Filed: November 11, 2008
    Publication date: May 14, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Syuhei Moribe, Katsuhisa Yamazaki, Daisuke Yoshiba, Masami Fujimoto
  • Publication number: 20080286676
    Abstract: A magnetic toner having magnetic toner particles each containing at least a binder resin and a magnetic iron oxide particle, in which: when a solution is prepared by dissolving the magnetic iron oxide particles in an acidic aqueous solution and an Fe element amount in a solution in which all the magnetic iron oxide particles are dissolved is defined as a total Fe element amount, a ratio X of the amount of Fe(2+) in a solution in which the magnetic iron oxide particles are dissolved to a state where 10 mass % of the total Fe element amount is present in the solution (solution having an Fe element-dissolving ratio of 10 mass %) to an Fe element amount in the solution having a specific Fe element-dissolving ratio; and the dielectric loss tangents of the magnetic toner measured at a temperature of 40° C. satisfy specific conditions.
    Type: Application
    Filed: July 24, 2008
    Publication date: November 20, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Daisuke Yoshiba, Katsuhisa Yamazaki
  • Publication number: 20080187853
    Abstract: The present invention aims to provide a toner having excellent developability and excellent low-temperature fixability without causing adhesion of ejected sheets even in a high-speed oilless fixing system and capable of preventing a frameless printing from causing a twisted offseting phenomenon. Specifically, provided is a toner having toner particles including at least a binder resin and a colorant, in which, when the toner is dissolved in a tetrahydrofuran (THF) solvent at 25° C. for 24 hours, the ratio of a THF-soluble matter having an intrinsic viscosity of 5.0×10?2 dl/g or less with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 15.0 mass % to 60.0 mass %, and the ratio of a THF-soluble matter having an intrinsic viscosity of 1.5×10?1 dl/g or more with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 20.0 mass % to 40.0 mass %.
    Type: Application
    Filed: March 27, 2008
    Publication date: August 7, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Syuhei Moribe, Katsuhisa Yamazaki, Daisuke Yoshiba, Junko Hirata, Masami Fujimoto, Takashige Kasuya
  • Publication number: 20080124643
    Abstract: A toner is provided which can stably provide a favorable density stability, line reproducibility and dot reproducibility even in high-speed copying machines, printers and the like which form high resolution latent images over a long period regardless of environmental conditions, and can provide the image quality adaptable to embedded pattern printing, QR code printing and the like. The present invention is characterized in that the toner which includes toner particles including at least a binder resin and a colorant, and a fine silica powder, has a volume median diameter (D50) of not less than 0.70 ?m and not more than 3.00 ?m, and a total pore volume of not more than 0.200 cm3/g, measured in the range of the pore diameter from not less than 1.7 nm and not more than 300.0 nm.
    Type: Application
    Filed: November 29, 2007
    Publication date: May 29, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Daisuke Yoshiba, Katsuhisa Yamazaki, Syuhei Moribe, Junko Nishiyama, Shuichi Hiroko, Masami Fujimoto, Takashige Kasuya
  • Publication number: 20070224530
    Abstract: To provide a developer and an image forming method with each of which a high-resolution, high-definition image can be stably obtained over a long time period irrespective of an environment. The present invention provides a developer including at least: toner particles each containing at least a binder resin; and a composite inorganic fine powder, the developer being characterized in that: the composite inorganic fine powder has a peak at a Bragg angle (2?±0.20 deg) of each of 32.20 deg, 25.80 deg, and 27.50 deg in a CuK? characteristic X-ray diffraction pattern; and the half width of the X-ray diffraction peak at a Bragg angle (2?±0.20 deg) of 32.20 deg is 0.20 to 0.30 deg.
    Type: Application
    Filed: May 30, 2007
    Publication date: September 27, 2007
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Takakuni Kobori, Kenji Okado, Masami Fujimoto, Katsuhisa Yamazaki, Syuhei Moribe, Daisuke Yoshiba
  • Publication number: 20060160006
    Abstract: A positively chargeable developer is provided which is capable of providing stable image quality without causing any image defect even in long-term use. The developer includes at least positively chargeable toner particles each containing at least a binder resin and magnetic iron oxide, silica and an inorganic fine powder. A unconfined yield strength at a major consolidation stress of 5 kPa of the developer is in the range of 0.1 to 2.5 kPa, and a unconfined yield strength at a major consolidation stress of 20 kPa of the developer is in the range of 2.5 to 5.5 kPa.
    Type: Application
    Filed: February 16, 2006
    Publication date: July 20, 2006
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Katsuhisa Yamazaki, Daisuke Yoshiba, Masami Fujimoto
  • Publication number: 20060141380
    Abstract: To provide a toner which allows low temperature fixation irrespective of the configuration of a fuser, which is excellent in offset resistance, and which provides high image quality at high and low humidities in a stable manner without causing any image defect over time. A toner containing: a binder resin and a colorant; in which the toner contains a THF-soluble component to be dissolved in tetrahydrofuran (THF); the binder resin component contained in the THF-soluble component contains: a vinyl resin unit (I) formed by at least a carboxyl group-containing vinyl resin and an epoxy group-containing vinyl resin and having an epoxy value of 0.001 to 1.
    Type: Application
    Filed: December 6, 2005
    Publication date: June 29, 2006
    Applicant: Canon Kabushiki Kaisha
    Inventors: Katsuhisa Yamazaki, Masami Fujimoto, Daisuke Yoshiba