Patents by Inventor Keita Sensui

Keita Sensui 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: 8962232
    Abstract: A production process of a polymerized toner composed of polymer particles, including a step of polymerizing a polymerizable monomer composition containing a colorant and a polymerizable monomer in the presence of a polymerization initiator in an aqueous dispersion medium, wherein, in a stripping treatment step, the dispersion containing the polymer particles is introduced into an evaporator to conduct the stripping treatment by a method, in which a gas is blown into the dispersion within the evaporator to discharge volatile organic components including an unreacted polymerizable monomer out of the evaporator concomitantly with the gas, and both inert gas and saturated steam are used as the gas blown into the dispersion.
    Type: Grant
    Filed: November 11, 2008
    Date of Patent: February 24, 2015
    Assignee: Zeon Corporation
    Inventor: Keita Sensui
  • Patent number: 8394565
    Abstract: A positively charged developer for development of electrostatic images, comprising positively charged toner particles and an external additive, wherein the positively charged toner particles are colored resin particles composed of aggregated and fusion-bonded particles of fine binder resin particles and fine colorant particles and having a shape factor SF-1 of 115 to 150 and a shape factor SF-2 of 110 to 140, and the external additive is an external additive containing positively charged inorganic particles subjected to a hydrophobization treatment with an amino group-containing compound, and a production process thereof.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: March 12, 2013
    Assignee: Zeon Corporation
    Inventor: Keita Sensui
  • Patent number: 8173345
    Abstract: [PROBLEMS] To provide a toner superior in shelf stability, not giving off an offensive odor and degrading the surrounding environment when used for printing, and superior in durability at the time of use for continuous printing under high temperature, high humidity conditions. [MEANS FOR SOLVING PROBLEMS] A process of production of a toner containing colored polymer particles obtained by polymerizing a polymerizable monomer composition containing a polymerizable monomer and colorant in an aqueous medium in the presence of a polymerization initiator, wherein the polymerization initiator is an organic peroxide having a molecular weight of 205 or less, and a purity of 90% or more.
    Type: Grant
    Filed: July 13, 2006
    Date of Patent: May 8, 2012
    Assignee: Zeon Corporation
    Inventor: Keita Sensui
  • Patent number: 8067140
    Abstract: A toner for developing electrostatic image which has a reduced residual amount of a decomposed product of a polymerization initiator remaining in the toner upon production (mainly an ether component) and an unreacted polymerizable monomer (mainly styrene), less odor produced upon fixing so as to avoid deteriorating surrounding environment, an excellent shelf stability at high temperature upon storing or anti-blocking property, and an excellent printing durability under both N/N environment and H/H environment upon printing is provided. A toner for developing electrostatic image comprising a colored resin particle which is obtained by polymerizing a polymerizable monomer composition containing a polymerizable monomer, a colorant and a charge control resin in an aqueous dispersion medium in the presence of a polymerization initiator, wherein the charge control resin is a quaternary ammonium base containing copolymer having a glass transition temperature “Tg” in the range from 70 to 100° C.
    Type: Grant
    Filed: January 30, 2008
    Date of Patent: November 29, 2011
    Assignee: Zeon Corporation
    Inventor: Keita Sensui
  • Publication number: 20100248132
    Abstract: A production process of a polymerized toner composed of polymer particles, including a step of polymerizing a polymerizable monomer composition containing a colorant and a polymerizable monomer in the presence of a polymerization initiator in an aqueous dispersion medium, wherein, in a stripping treatment step, the dispersion containing the polymer particles is introduced into an evaporator to conduct the stripping treatment by a method, in which a gas is blown into the dispersion within the evaporator to discharge volatile organic components including an unreacted polymerizable monomer out of the evaporator concomitantly with the gas, and both inert gas and saturated steam are used as the gas blown into the dispersion.
    Type: Application
    Filed: November 11, 2008
    Publication date: September 30, 2010
    Applicant: ZEON CORPORATION
    Inventor: Keita Sensui
  • Publication number: 20100173240
    Abstract: A positively charged developer for development of electrostatic images, comprising positively charged toner particles and an external additive, wherein the positively charged toner particles are colored resin particles composed of aggregated and fusion-bonded particles of fine binder resin particles and fine colorant particles and having a shape factor SF-1 of 115 to 150 and a shape factor SF-2 of 110 to 140, and the external additive is an external additive containing positively charged inorganic particles subjected to a hydrophobization treatment with an amino group-containing compound, and a production process thereof.
    Type: Application
    Filed: March 30, 2007
    Publication date: July 8, 2010
    Applicant: ZEON CORPORATION
    Inventor: Keita Sensui
  • Patent number: 7709176
    Abstract: A method for producing a polymerized toner comprising a step of polymerizing a polymerizable monomer composition in an aqueous dispersion medium in the presence of a polymerization initiator to obtain a dispersion liquid of colored polymer particles and a stripping step of injecting a gas comprised of air or an inert gas into the dispersion liquid of the colored polymer particles while stirring the dispersion liquid in an evaporator and the flow rate of the gas injected per weight of the colored polymer particles being 0.05 to 4 L/(hr·kg), the pressure of the vapor phase of the evaporator being 5 to 80 kPa.
    Type: Grant
    Filed: August 29, 2006
    Date of Patent: May 4, 2010
    Assignee: Zeon Corporation
    Inventors: Junichi Takashima, Takashi Iga, Keita Sensui
  • Patent number: 7611814
    Abstract: An object of the present invention is to provide a polymerized toner which has low-temperature fixing ability and is not likely to leak the toner from a developing cartridge, especially, when the toner is used for a high-speed image-forming device. A polymerized toner produced by polymerizing a polymerizable monomer composition comprising a polymerizable monomer, a colorant and a release agent in an aqueous medium is used, wherein: (1) the release agent is an ester compound; (2) the release agent is in the content from 1 part by weight or more to 9 parts by weight or less per 100 parts by weight of a monovinyl monomer in the polymerizable monomer; (3) a maximum endothermic peak temperature in a DSC curve of the release agent is in the range from 55° C. or more to 90° C. or less; and (4) a melt index value of the polymerized toner at 150° C. under load of 98 N (10 kgf) is in the range from 1 g/10 min or more to 30 g/10 min or less.
    Type: Grant
    Filed: September 28, 2005
    Date of Patent: November 3, 2009
    Assignee: Zeon Corporation
    Inventor: Keita Sensui
  • Publication number: 20090130578
    Abstract: [Problems] To provide a toner superior in shelf stability, not giving off an offensive odor and degrading the surrounding environment when used for printing, and superior in durability at the time of use for continuous printing under high temperature, high humidity conditions. [Means for Solving Problems] A process of production of a toner containing colored polymer particles obtained by polymerizing a polymerizable monomer composition containing a polymerizable monomer and colorant in an aqueous medium in the presence of a polymerization initiator, wherein the polymerization initiator is an organic peroxide having a molecular weight of 205 or less, and a purity of 90% or more.
    Type: Application
    Filed: July 13, 2006
    Publication date: May 21, 2009
    Applicant: ZEON CORPORATION
    Inventor: Keita Sensui
  • Publication number: 20080182189
    Abstract: A toner for developing electrostatic image which has a reduced residual amount of a decomposed product of a polymerization initiator remaining in the toner upon production (mainly an ether component) and an unreacted polymerizable monomer (mainly styrene), less odor produced upon fixing so as to avoid deteriorating surrounding environment, an excellent shelf stability at high temperature upon storing or anti-blocking property, and an excellent printing durability under both N/N environment and H/H environment upon printing is provided. A toner for developing electrostatic image comprising a colored resin particle which is obtained by polymerizing a polymerizable monomer composition containing a polymerizable monomer, a colorant and a charge control resin in an aqueous dispersion medium in the presence of a polymerization initiator, wherein the charge control resin is a quaternary ammonium base containing copolymer having a glass transition temperature “Tg” in the range from 70 to 100° C.
    Type: Application
    Filed: January 30, 2008
    Publication date: July 31, 2008
    Applicant: ZEON CORPORATION
    Inventor: Keita SENSUI
  • Publication number: 20080160434
    Abstract: The present invention provides a toner for developing an electrostatic latent image which is capable of obtaining sufficient image density and preventing transfer failure even in a state that a toner is likely to be deficient in charge amount or charge distribution such as when the consumption rate of toner is high or in the early stage of printing. A toner for developing an electrostatic latent image is a toner comprising a colored particle containing a colorant and a binder resin, wherein a work function X (eV) of the toner obtained in measuring work function and a gradient A (1/eV) of a normalized photoelectron yield with respect to an excitation energy calculated from a formula “normalized photoelectron yield/excitation energy” are in the ranges of 5.35<X<5.60 and A?55X+290>0, is disclosed.
    Type: Application
    Filed: December 13, 2005
    Publication date: July 3, 2008
    Applicant: Zeon Corporation
    Inventors: Keita Sensui, Hiroto Kidokoro
  • Publication number: 20070048645
    Abstract: A method for producing a polymerized toner comprising a step of polymerizing a polymerizable monomer composition in an aqueous dispersion medium in the presence of a polymerization initiator to obtain a dispersion liquid of colored polymer particles and a stripping step of injecting a gas comprised of air or an inert gas into the dispersion liquid of the colored polymer particles while stirring the dispersion liquid in an evaporator and the flow rate of the gas injected per weight of the colored polymer particles being 0.05 to 4 L/(hr·kg), the pressure of the vapor phase of the evaporator being 5 to 80 kPa.
    Type: Application
    Filed: August 29, 2006
    Publication date: March 1, 2007
    Applicant: ZEON CORPORATION
    Inventors: Junichi Takashima, Takashi Iga, Keita Sensui
  • Publication number: 20060073402
    Abstract: An object of the present invention is to provide a polymerized toner which has low-temperature fixing ability and is not likely to leak the toner from a developing cartridge, especially, when the toner is used for a high-speed image-forming device. A polymerized toner produced by polymerizing a polymerizable monomer composition comprising a polymerizable monomer, a colorant and a release agent in an aqueous medium is used, wherein: (1) the release agent is an ester compound; (2) the release agent is in the content from 1 part by weight or more to 9 parts by weight or less per 100 parts by weight of a monovinyl monomer in the polymerizable monomer; (3) a maximum endothermic peak temperature in a DSC curve of the release agent is in the range from 55° C. or more to 90° C. or less; and (4) a melt index value of the polymerized toner at 150° C. under load of 98 N (10 kgf) is in the range from 1 g/10 min or more to 30 g/10 min or less.
    Type: Application
    Filed: September 28, 2005
    Publication date: April 6, 2006
    Applicant: ZEON CORPORATION
    Inventor: Keita Sensui
  • Patent number: 6939656
    Abstract: Methods for producing a polymerized toners are provided, where, a dispersion including colored polymer particles obtained by polymerizing a polymerizable composition is treated stably in the process of reducing the remaining monomer, the resultant polymerized toners include a sufficiently low content of remaining monomer, and the resultant polymerized toners have excellent properties and are useful as developers for printing and copying. In the process of reducing the remaining monomer, the dispersion of the colored polymer particles is treated by stripping in the presence of a specific antifoaming agent.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: September 6, 2005
    Assignee: Zeon Corporation
    Inventors: Katsutomo Tanaka, Makoto Watanabe, Keita Sensui
  • Publication number: 20040110081
    Abstract: Methods for producing a polymerized toners are provided, where, a dispersion including colored polymer particles obtained by polymerizing a polymerizable composition is treated stably in the process of reducing the remaining monomer, the resultant polymerized toners include a sufficiently low content of remaining monomer, and the resultant polymerized toners have excellent properties and are useful as developers for printing and copying. In the process of reducing the remaining monomer, the dispersion of the colored polymer particles is treated by stripping in the presence of a specific antifoaming agent.
    Type: Application
    Filed: July 31, 2003
    Publication date: June 10, 2004
    Inventors: Katsutomo Tanaka, Makoto Watanabe, Keita Sensui