Patents by Inventor Kazu Niwa

Kazu Niwa 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: 10691037
    Abstract: To provide a method for producing a rubber composition which gives a cross-linked rubber which has a low volume resistivity value, which is low in hardness, and which is kept down in contamination of the photoconductor when used as a conductive member. A production method of a rubber composition comprising a step of mixing a polyether rubber which is dissolved in a solvent at 0.1 to 30 wt % of concentration and a liquid ethylenically unsaturated nitrile-conjugated diene copolymer rubber in a solution is provided.
    Type: Grant
    Filed: November 14, 2018
    Date of Patent: June 23, 2020
    Assignees: ZEON CORPORATION, ZEON CHEMICALS L.P.
    Inventors: Kazu Niwa, Clark Cable
  • Publication number: 20190079426
    Abstract: To provide a method for producing a rubber composition which gives a cross-linked rubber which has a low volume resistivity value, which is low in hardness, and which is kept down in contamination of the photoconductor when used as a conductive member. A production method of a rubber composition comprising a step of mixing a polyether rubber which is dissolved in a solvent at 0.1 to 30 wt % of concentration and a liquid ethylenically unsaturated nitrile-conjugated diene copolymer rubber in a solution is provided.
    Type: Application
    Filed: November 14, 2018
    Publication date: March 14, 2019
    Applicants: ZEON CORPORATION, ZEON Chemicals L.P.
    Inventors: Kazu Niwa, Clark Cable
  • Patent number: 9771454
    Abstract: A method of production of a polyether rubber containing units expressed by the following general formula (1) in 0.1 mol % to less than 30 mol % including reacting a polyether rubber containing epihalohydrin monomer units in 0.1 mol % or more and a nitrogen atom-containing aromatic heterocyclic compound by kneading in the presence of an acid acceptor using an extruder-kneader so as to make at least part of halogen atoms forming the epihalohydrin monomer units be substituted by a group containing a cationic nitrogen-containing aromatic heterocyclic structure is provided. (wherein, in the above general formula (1), A+ is a group containing a cationic nitrogen-containing aromatic heterocyclic structure, where the group containing a cationic nitrogen-containing aromatic heterocyclic structure is bonded with a carbon atom at the “2” position shown in the above general formula (1) through a nitrogen atom forming the cationic nitrogen-containing aromatic heterocyclic structure, and X? is any counter anion.
    Type: Grant
    Filed: December 25, 2014
    Date of Patent: September 26, 2017
    Assignee: ZEON CORPORATION
    Inventors: Tomoyuki Narita, Kazu Niwa
  • Patent number: 9732188
    Abstract: A method of production of a polyether rubber containing units expressed by the following general formula (1) in 0.1 mol % to less than 30 mol % including reacting a polyether rubber containing epihalohydrin monomer units in 0.1 mol % or more and a nitrogen atom-containing aromatic heterocyclic compound by kneading in the presence of an acid acceptor using an extruder-kneader so as to make at least part of halogen atoms forming the epihalohydrin monomer units be substituted by a group containing a cationic nitrogen-containing aromatic heterocyclic structure is provided. (wherein, in the above general formula (1), A+ is a group containing a cationic nitrogen-containing aromatic heterocyclic structure, where the group containing a cationic nitrogen-containing aromatic heterocyclic structure is bonded with a carbon atom at the “2” position shown in the above general formula (1) through a nitrogen atom forming the cationic nitrogen-containing aromatic heterocyclic structure, and X? is any counter anion.
    Type: Grant
    Filed: December 25, 2014
    Date of Patent: August 15, 2017
    Assignee: ZEON CORPORATION
    Inventors: Tomoyuki Narita, Kazu Niwa
  • Publication number: 20170029564
    Abstract: A method of production of a polyether rubber containing units expressed by the following general formula (1) in 0.1 mol % to less than 30 mol % including reacting a polyether rubber containing epihalohydrin monomer units in 0.1 mol % or more and a nitrogen atom-containing aromatic heterocyclic compound by kneading in the presence of an acid acceptor using an extruder-kneader so as to make at least part of halogen atoms forming the epihalohydrin monomer units be substituted by a group containing a cationic nitrogen-containing aromatic heterocyclic structure is provided. (wherein, in the above general formula (1), A+ is a group containing a cationic nitrogen-containing aromatic heterocyclic structure, where the group containing a cationic nitrogen-containing aromatic heterocyclic structure is bonded with a carbon atom at the “2” position shown in the above general formula (1) through a nitrogen atom forming the cationic nitrogen-containing aromatic heterocyclic structure, and X? is any counter anion.
    Type: Application
    Filed: December 25, 2014
    Publication date: February 2, 2017
    Applicant: ZEON CORPORATION
    Inventors: Tomoyuki NARITA, Kazu NIWA
  • Publication number: 20140097388
    Abstract: A method for producing a rubber composition which gives a cross-linked rubber which has a low volume resistivity value, which is low in hardness, and which is kept down in contamination of the photoconductor when used as a conductive member is provided, that is, a production method of a rubber composition comprising a step of mixing a polyether rubber which is dissolved in a solvent at 0.1 to 30 wt % of concentration and a liquid ethylenically unsaturated nitrile-conjugated diene copolymer rubber in a solution is provided.
    Type: Application
    Filed: October 3, 2013
    Publication date: April 10, 2014
    Applicants: ZEON Chemicals L.P., ZEON CORPORATION
    Inventors: Kazu NIWA, Clark CABLE
  • Patent number: 8092969
    Abstract: A process for forming a full-color image, wherein the 4 color toners each have an apparent viscosity at 105° C. of 50,000 to 300,000 Pa·s and an apparent viscosity at 130° C. of 3,000 to 30,000 Pa·s, and as a color toner arranged at the outermost layer on a transfer medium among the 4 color toners, a toner, in which a maximum peak or a shoulder peak is present between 105° C. and 130° C. in a temperature-logarithmic melt viscosity graph, is used, and as the other color toners arranged at lower layers than the outermost layer, toners, in which neither the maximum peak nor the shoulder peak is present between 105° C. and 130° C., are used.
    Type: Grant
    Filed: March 31, 2008
    Date of Patent: January 10, 2012
    Assignee: Zeon Corporation
    Inventor: Kazu Niwa
  • Publication number: 20080241719
    Abstract: A process for forming a full-color image, wherein the 4 color toners each have an apparent viscosity at 105° C. of 50,000 to 300,000 Pa·s and an apparent viscosity at 130° C. of 3,000 to 30,000 Pa·s, and as a color toner arranged at the outermost layer on a transfer medium among the 4 color toners, a toner, in which a maximum peak or a shoulder peak is present between 105° C. and 130° C. in a temperature-logarithmic melt viscosity graph, is used, and as the other color toners arranged at lower layers than the outermost layer, toners, in which neither the maximum peak nor the shoulder peak is present between 105° C. and 130° C., are used.
    Type: Application
    Filed: March 31, 2008
    Publication date: October 2, 2008
    Applicant: ZEON CORPORATION
    Inventor: Kazu Niwa
  • Patent number: 7422833
    Abstract: A charge control resin composition for positive or negative charge, which is prepared either by mixing and kneading a charge control resin for positive or negative charge with a colorant, or by mixing and kneading the above combination further with a charge control resin for opposite charge or a charge control resin composition for opposite charge; wherein colorant particles are finely dispersed as desired. The resultant mixture is mixed with a polymerizable monomer to obtain polymerizable monomer composition. Then, the polymerizable monomer composition is dispersed or emulsified in an aqueous dispersion medium containing a dispersion stabilizer, and polymerized to obtain a toner.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: September 9, 2008
    Assignee: Zeon Corporation
    Inventors: Kazu Niwa, Fuminari Oyama
  • Patent number: 7378207
    Abstract: The invention relates to a magenta toner having magenta-colored resin particles comprising at least a binder resin and a magenta colorant. The magenta pigment is a magenta pigment composed of a combination of C.I. Pigment Red 31 and C.I. Pigment Red 150.
    Type: Grant
    Filed: September 5, 2003
    Date of Patent: May 27, 2008
    Assignee: Zeon Corporation
    Inventors: Fuminari Oyama, Kazu Niwa
  • Publication number: 20050250033
    Abstract: The invention relates to a magenta toner having magenta-colored resin particles comprising at least a binder resin and a magenta colorant. The magenta pigment is a magenta pigment composed of a combination of C.I. Pigment Red 31 and C.I. Pigment Red 150.
    Type: Application
    Filed: September 5, 2003
    Publication date: November 10, 2005
    Inventors: Fuminari Oyama, Kazu Niwa
  • Patent number: 6887637
    Abstract: A toner for electrostatic image development, which comprises a binder resin, a colorant and a charge control resin, wherein the charge control resin is a copolymer composed a vinyl monomer unit and a quaternary ammonium salt group-containing (meth)acrylate monomer unit and has a glass transition temperature of 40 to 75° C., and a production process thereof.
    Type: Grant
    Filed: February 13, 2001
    Date of Patent: May 3, 2005
    Assignee: Zeon Corporation
    Inventor: Kazu Niwa
  • Publication number: 20040013961
    Abstract: A toner comprising a binder resin, a colorant and a charge control resin for positive and/or negative charge, wherein a number of colorant particles having a length of at least 0.2 mm counted in an area of 100 mm×100 mm of a toner having a thickness of 20 mm, which is prepared by melting the toner, being at most 50.
    Type: Application
    Filed: March 21, 2003
    Publication date: January 22, 2004
    Inventors: Kazu Niwa, Fuminari Oyama
  • Patent number: 6562535
    Abstract: A toner for development of electrostatic images, comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent contains a positive charge control resin (A) composed of a polymer having a weight average molecular weight of 1,000 to 100,000 and a functional group which brings positively charging ability, and a negative charge control resin (B) composed of a polymer having a weight average molecular weight of 1,000 to 100,000 and a functional group which brings negatively charging ability. The toner is excellent in flowability, shelf stability and charge properties, and provides images excellent in image quality.
    Type: Grant
    Filed: September 25, 2001
    Date of Patent: May 13, 2003
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Kojiro Masuo, Shuichi Yokoyama, Takuji Kishimoto, Kazu Niwa
  • Publication number: 20030027070
    Abstract: A toner for electrostatic image development, which comprises a binder resin, a colorant and a charge control resin, wherein the charge control resin is a copolymer composed a vinyl monomer unit and a quaternary ammonium salt group-containing (meth)acrylate monomer unit and has a glass transition temperature of 40 to 75° C., and a production process thereof.
    Type: Application
    Filed: August 8, 2002
    Publication date: February 6, 2003
    Inventor: Kazu Niwa
  • Patent number: 6342328
    Abstract: A toner for development of electrostatic images, comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent is a polar resin composed of a copolymer of a vinyl monomer and SO3X (X=H or alkali metal) group-containing (meth)acrylamide and having an SO3X group-containing (meth)acrylamide unit content of 0.1 to 10 wt. % and a weight average molecular weight of 17,000 to 25,000, and a production process of the toner.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: January 29, 2002
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Takahiro Takasaki, Kazu Niwa, Kojiro Masuo, Kazuhiro Sato