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).
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Patent number: 8962232Abstract: 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: GrantFiled: November 11, 2008Date of Patent: February 24, 2015Assignee: Zeon CorporationInventor: Keita Sensui
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Patent number: 8394565Abstract: 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: GrantFiled: March 30, 2007Date of Patent: March 12, 2013Assignee: Zeon CorporationInventor: Keita Sensui
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Patent number: 8173345Abstract: [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: GrantFiled: July 13, 2006Date of Patent: May 8, 2012Assignee: Zeon CorporationInventor: Keita Sensui
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Patent number: 8067140Abstract: 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: GrantFiled: January 30, 2008Date of Patent: November 29, 2011Assignee: Zeon CorporationInventor: Keita Sensui
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Publication number: 20100248132Abstract: 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: ApplicationFiled: November 11, 2008Publication date: September 30, 2010Applicant: ZEON CORPORATIONInventor: Keita Sensui
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Publication number: 20100173240Abstract: 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: ApplicationFiled: March 30, 2007Publication date: July 8, 2010Applicant: ZEON CORPORATIONInventor: Keita Sensui
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Patent number: 7709176Abstract: 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: GrantFiled: August 29, 2006Date of Patent: May 4, 2010Assignee: Zeon CorporationInventors: Junichi Takashima, Takashi Iga, Keita Sensui
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Patent number: 7611814Abstract: 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: GrantFiled: September 28, 2005Date of Patent: November 3, 2009Assignee: Zeon CorporationInventor: Keita Sensui
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Publication number: 20090130578Abstract: [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: ApplicationFiled: July 13, 2006Publication date: May 21, 2009Applicant: ZEON CORPORATIONInventor: Keita Sensui
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Publication number: 20080182189Abstract: 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: ApplicationFiled: January 30, 2008Publication date: July 31, 2008Applicant: ZEON CORPORATIONInventor: Keita SENSUI
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Publication number: 20080160434Abstract: 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: ApplicationFiled: December 13, 2005Publication date: July 3, 2008Applicant: Zeon CorporationInventors: Keita Sensui, Hiroto Kidokoro
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Publication number: 20070048645Abstract: 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: ApplicationFiled: August 29, 2006Publication date: March 1, 2007Applicant: ZEON CORPORATIONInventors: Junichi Takashima, Takashi Iga, Keita Sensui
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Publication number: 20060073402Abstract: 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: ApplicationFiled: September 28, 2005Publication date: April 6, 2006Applicant: ZEON CORPORATIONInventor: Keita Sensui
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Patent number: 6939656Abstract: 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: GrantFiled: July 31, 2003Date of Patent: September 6, 2005Assignee: Zeon CorporationInventors: Katsutomo Tanaka, Makoto Watanabe, Keita Sensui
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Publication number: 20040110081Abstract: 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: ApplicationFiled: July 31, 2003Publication date: June 10, 2004Inventors: Katsutomo Tanaka, Makoto Watanabe, Keita Sensui