Patents by Inventor Yoshinobu Nagai

Yoshinobu Nagai 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: 5333059
    Abstract: The present invention provide a toner for developing an electrostatic image. The toner comprises a binder resin and a coloring agent. The binder resin comprises a styrene type binder resin. The amount of an aldehyde contained in the binder resin is not more than 0.005% by weight based on the weight of the toner. The binder resin is produced by a process comprising the steps of preparing a monomer composition comprising a polymerizable monomer containing at least not less than 50% by weight of a styrene monomer, and a polymerization initiator, and subjecting said monomer composition to suspension polymerization in an aqueous medium having dissolved oxygen in an amount of not more than 2.5 mg/lit to form a styrene polymer or copolymer containing an aldehyde monomer in an amount of not more than 0.01% by weight.
    Type: Grant
    Filed: March 25, 1992
    Date of Patent: July 26, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshihiko Hyosu, Seiichi Takagi, Hiroyuki Suematsu, Manabu Ohno, Tetsuhito Kuwashima, Eiichi Imai, Yoshinobu Nagai
  • Patent number: 5310812
    Abstract: A toner for developing electrostatic latent images with a good combination of fixability, anti-offset characteristic, anti-sticking characteristic and pulverizability contains a composition comprising a colorant or magnetic material and a binder resin. The binder resin has 0.1 to 60 wt. % of a chloroform-insoluble or a THF (tetrahydrofuran)-insoluble component and a THF-soluble component, the THF-soluble providing a molecular weight distribution in the chromatogram of GPC (gel permeation chromatography) thereof such that there is a main peak in the molecular weight range of 1,000 to 25,000 and a sub-peak or shoulder in the molecular weight range of 2,000 to 150,000. The binder resin may suitably be obtained through two polymerization steps including a solution polymerization step and a suspension polymerization step.
    Type: Grant
    Filed: December 7, 1992
    Date of Patent: May 10, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Satoshi Yasuda, Kiichiro Sakashita, Yasuo Mitsuhashi, Seiichi Takagi, Shuichi Aita, Yoshinobu Nagai, Toshiaki Nakahara
  • Patent number: 5219947
    Abstract: A toner for developing electrostatic latent images with a good combination of fixability, anti-offset characteristic, anti-sticking characteristic and pulverizability is provided as a composition comprising a colorant or magnetic material and a binder resin. The binder resin has 0.1 to 60 wt. % of a chloroform-insoluble or a THF (tetrahydrofuran)insoluble and a THF-soluble, the THF-soluble providing a molecular weight distribution in the chromatogram of GPC (gel permeation chromatography) thereof such that there are a main peak in the molecular weight range of 1,000 to 25,000 and a sub-peak or shoulder in the molecular weight range of 2,000 to 150,000. The binder resin may suitably be obtained through two polymerization steps including a solution polymerization step and a suspension polymerization step.
    Type: Grant
    Filed: April 23, 1990
    Date of Patent: June 15, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Satoshi Yasuda, Kiichiro Sakashita, Yasuo Mitsuhashi, Seiichi Takagi, Shuichi Aita, Yoshinobu Nagai, Toshiaki Nakahara
  • Patent number: 5126224
    Abstract: The present invention provide a toner for developing an electrostatic image. The toner comprises a binder resin and a coloring agent. The binder resin comprises a styrene type binder resin. The amount of an aldehyde contained in the binder resin is not more than 0.005% by weight based on the weight of the toner. The binder resin is produced by a process comprising the steps of preparing a monomer composition comprising a polymerizable monomer containing at least not less than 50% by weight of a styrene monomer, and a polymerization initiator, and subjecting said monomer composition to suspension polymerization in an aqueous medium having dissolved oxygen in an amount of not more than 2.5 mg/lit to form a styrene polymer or copolymer containing an aldehyde monomer in an amount of not more than 0.01% by weight.
    Type: Grant
    Filed: September 14, 1990
    Date of Patent: June 30, 1992
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshihiko Hyosu, Seiichi Takagi, Hiroyuki Suematsu, Manabu Ohno, Tetsuhito Kuwashima, Eiichi Imai, Yoshinobu Nagai
  • Patent number: 4966829
    Abstract: A toner for developing electrostatic latent images with a good combination of fixability, anti-offset characteristic, anti-sticking characteristic and pulverizability is provided as a composition comprising a colorant or magnetic material and a binder resin. The binder resin has 0.1 to 60 wt. % of a chloroform-insoluble or a THF (tetrahydrofuran)-insoluble and a THF-soluble, the THF-soluble providing a molecular weight distribution in the chromatogram of GPC (gel permeation chromatography) thereof such that there are a main peak in the molecular weight range of 1,000 to 25,000 and a sub-peak or shoulder in the molecular weight range of 2,000 to 150,000. The binder resin may suitably be obtained through two polymerization steps including a solution polymerization step and a suspension polymerization step.
    Type: Grant
    Filed: November 23, 1988
    Date of Patent: October 30, 1990
    Assignee: Canon Kabushiki Kaisha
    Inventors: Satoshi Yasuda, Kiichiro Sakashita, Yasuo Mitsuhashi, Seiichi Takagi, Shuichi Aita, Yoshinobu Nagai, Toshiaki Nakahara