Patents by Inventor Nobuhiro Hirayama
Nobuhiro Hirayama 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: 6011119Abstract: A resin composition is provided for an electro-photographic toner. The composition comprises 5 to 95 parts by weight of a high molecular weight vinyl copolymer polymer and 95 to 5 parts by weight of a low molecular weight vinyl copolymer. The former ethylene polymer has a weight average molecular weight (Mw) of from 200,000 to 1,000,000 and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to a number average molecular weight (Mn) of from 8 to 300, and the latter vinyl copolymer has a weight average molecular weight of from 3,000 to 20,000. At least one of the former and latter vinyl copolymer, preferably, the former vinyl copolymer is an ethylene polymer which has been obtained by conducting polymerization in the presence of a monomer having an ionization potential of from 10.0 to 15.0 eV and a difference of from 9.0 to 15.0 eV in level between a highest occupied molecular orbital (HOMO) and a lowest unoccupied molecular orbital (LUMO), both determined by computational chemistry.Type: GrantFiled: July 19, 1996Date of Patent: January 4, 2000Assignee: Mitsui Chemicals, Inc.Inventors: Katsuru Matsumoto, Nobuhiro Hirayama, Eishi Tanaka, Junko Tobita
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Patent number: 5677409Abstract: Described herein are propylene waxes and a production process thereof. The waxes are each produced by polymerizing propylene in a reaction vessel while using a solid catalyst in the presence or absence of an organoaluminum compound. A hydrogen partial pressure of a gas phase in the reaction vessel, said gas phase being formed of the propylene and hydrogen, is maintained at 10% or higher. The solid catalyst is formed of a transition metal compound or a reaction product between the transition metal compound and an organometallic compound, an aluminoxane and a fine particulate carrier. Also described herein is a heating-roll fixing type toner composition composed essentially of a binder resin or a binder resin composition, a colorant and, as a releasing agent, the wax.Type: GrantFiled: May 8, 1995Date of Patent: October 14, 1997Assignee: Mitsui Toatsu Chemicals, Inc.Inventors: Norihide Inoue, Masahiro Kouno, Yoshiho Sonobe, Kazumi Mizutani, Tetsunosuke Shiomura, Nobuhiro Hirayama
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Patent number: 5658999Abstract: Described herein are propylene waxes and a production process thereof. The waxes are each produced by polymerizing propylene in a reaction vessel while using a solid catalyst in the presence or absence of an organoaluminum compound. A hydrogen partial pressure of a gas phase in the reaction vessel, said gas phase being formed of the propylene and hydrogen, is maintained at 10% or higher. The solid catalyst is formed of a transition metal compound or a reaction product between the transition metal compound and an organometallic compound, an aluminoxane and a fine particulate carrier. Also described herein is a heating-roll fixing type toner composition composed essentially of a binder resin or a binder resin composition, a colorant and, as a releasing agent, the wax.Type: GrantFiled: October 16, 1995Date of Patent: August 19, 1997Assignee: Mitsui Toatsu Chemicals, Inc.Inventors: Norihide Inoue, Masahiro Kouno, Yoshiho Sonobe, Kazumi Mizutani, Tetsunosuke Shiomura, Nobuhiro Hirayama
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Patent number: 5573881Abstract: A toner composition for electrophotography comprises at least a binder, a coloring agent and optionally a low molecular weight wax in an amount ranging from 0.5 to 20 parts by weight per 100 parts by weight of the binder as essential components wherein the binder comprises, as a principal component, a resin mixture prepared by heating a resin solution comprising a styrene resin and a block copolymer which comprises blocks derived from at least one member selected from ethylenic hydrocarbons and conjugated diene hydrocarbons and blocks derived from styrene and/or a hydrogenated product thereof in an amount ranging from 0.1 to 20 parts by weight per 100 parts by weight of the styrene resin to remove the solvent. The low molecular weight wax may be included in the binder.Type: GrantFiled: June 7, 1995Date of Patent: November 12, 1996Assignee: Mitsui Toatsu Chemicals, Inc.Inventors: Shoji Kawasaki, Nobuhiro Hirayama, Kenji Uchiyama, Hisatomo Sato, Hiromi Akiyama, Katuo Uramoto
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Patent number: 5502110Abstract: A resin composition for an electrophotographic toner is here disclosed which comprises an ethylene series high polymer (Y) and an ethylene series polymer (X) prepared from 100 parts of a bifunctional ethylene series unsaturated monomer and 0.01-10 parts by weight of a substance having three or more peroxide groups in the molecule and/or a substance having one or more unsaturated functional groups and one or more peroxide groups in the molecule, Mw/Mb (Mw is weight-average molecular weight, and Mb is weight-average molecular weight between crosslinking points) of said polymer (X) being from 2 to 99, Mw of said polymer (X) being 50,000 or less. This resin composition is excellent in the balance of various physical properties required for the toner, and particularly, it is excellent in offset resistance and toner strength.Type: GrantFiled: April 27, 1993Date of Patent: March 26, 1996Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Katsuru Matsumoto, Nobuhiro Hirayama, Kenji Uchiyama, Shoji Kawasaki, Tamami Fukui, Katsuo Uramoto
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Patent number: 5468585Abstract: A resin composition for use in an electrophotographic toner which comprises an ethylenic polymer (L) having a M.sub.w of not greater than 20,000 and an acid value of 2 to 100 mg KOH/g, and an ethylenic polymer (H) having a M.sub.w of not less than 150,000, a M.sub.w /M.sub.n ratio of not less than 5.0 and a time constant for triboelectric charging (.tau.) of 1.2 to 25, the ethylenic polymers (L) and (H) being present in a weight ratio ranging from 15:85 to 85:15. This resin composition can improve the triboelectric charging properties of the toner.Type: GrantFiled: December 23, 1994Date of Patent: November 21, 1995Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Katsuru Matsumoto, Nobuhiro Hirayama, Shoji Kawasaki, Kenji Uchiyama, Katsuo Uramoto, Tamami Fukui
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Patent number: 5389483Abstract: The present invention provides electrophotographic toner which comprises as a principal component a mixture of 20-80 parts by weight of a first ethylene polymer (X) whose weight-average molecular weight (Mw) is at least 200,000 and a second ethylene polymer (Y) whose Z average molecular weight/number-average molecular weight (Mz/Mn) is at least 6 and Mw is not greater than 50,000. According to this invention, electrophotographic toner of wide non-offset range can be obtained and, images of stable quality in a low heat quantity, which have not been attained by the prior art, can be obtained.Type: GrantFiled: June 9, 1993Date of Patent: February 14, 1995Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Shoji Kawasaki, Nobuhiro Hirayama, Kenji Uchiyama, Hisatomo Sato, Hiromi Akiyama
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Patent number: 5362595Abstract: This invention discloses electrophotographic toners and the methods for their preparation. The electrophotographic toners contain resin and coloring agents as primary components. The resin is a non-crosslinked polymer of vinyl monomers or its mixtures, and has a number average molecular weight (Mn) of 2,000-15,000, a Z average molecular weight (Mz) of not less than 400,000 and Mz/Mn of 50-600. The electrophotographic toners exert an excellent fixing ability at high duplication speed or at lower temperatures.Type: GrantFiled: October 26, 1992Date of Patent: November 8, 1994Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Nobuhiro Hirayama, Masaaki Shin, Shoji Kawasaki, Akira Misawa, Akio Fujiwara, Kenji Uchiyama
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Patent number: 5266434Abstract: The present invention provides an electrophotographic toner composition comprising a binder and a colorant. At least 70 wt. % of the binder are soluble in THF, the number average molecular weight (Mn) and Z average molecular weight (Mz) of the THF-soluble portion of the binder as measured using THF are 2,000-15,000 and at least 400,000, respectively. The particle size of the binder has been controlled so that D.sub.75 is not greater than 2.5 mm, D.sub.25 not smaller than 0.15 mm and D.sub.75 /D.sub.25 at least 1.5. The toner composition does not have variations from one lot to another. The quantity of electricity to be charged during a copying operation changes little. The picture quality can be maintained constant even during a long-time copying operation.Type: GrantFiled: August 6, 1991Date of Patent: November 30, 1993Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Nobuhiro Hirayama, Kenji Uchiyama, Shoji Kawasaki, Hisatomo Sato, Hiromi Akiyama
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Patent number: 5241019Abstract: Herein disclosed is a binder for dry toners which comprises a copolymer resin obtained by reacting 10 to 50% by weight of a polyester resin which has free carboxyl groups, whose acid value ranges from 10 to 100 and whose number-average molecular weight ranges from 1,000 to 5,000 and 90 to 50% by weight of a mixture of a vinyl compound having a glycidyl group and the an another vinyl compound, wherein the amount of the vinyl compound having a glycidyl group corresponds to the number of the glycidyl groups equal to 0.25 to 1.5 time that of the carboxyl groups present in the polyester resin. The binder for dry toners is used in the electrophotography technique.Type: GrantFiled: July 12, 1991Date of Patent: August 31, 1993Assignee: Mitsui Toatsu Chemicals, Inc.Inventors: Tateo Otsuki, Kazuya Tsukamoto, Nobuhiro Hirayama
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Patent number: 5230978Abstract: Disclosed herein is an electrophotographic toner composition produced by using a low-melt-viscosity and high-strength resin. The present invention provides a toner which fixes at low heat and has high strength and therefore, is suitable for high-speed copying machines and lower-heat copying machines. The resultant benefits of the present invention are that the lowest limit of the fixing temperature is low, non-offset range is wide and picture properties are good. The electrophotographic toner composition can, therefore, provide stable pictures even when fixed at low heat.Type: GrantFiled: August 14, 1991Date of Patent: July 27, 1993Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Shoji Kawasaki, Nobuhiro Hirayama, Kenji Uchiyama, Hisatomo Sato, Hiromi Akiyama
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Patent number: 5084368Abstract: This invention discloses electrophotogrpahic toners and the methods for their preparation. The electrophotographic toners contain resin and coloring agents as primary components. The resin is a non-crosslinked polymer of vinyl monomers or its mixtures, and has a number average molecular weight (Mn) of 2,000-15,000, a Z average molecular weight (Mz) of not less than 400,000 and Mz/Mn of 50-600. The electrophotographic toners exert an excellent fixing ability at high duplication speed or at lower temperatures.Type: GrantFiled: February 24, 1989Date of Patent: January 28, 1992Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Nobuhiro Hirayama, Masaaki Shin, Shoji Kawasaki, Akira Misawa, Akio Fujiwara, Kenji Uchiyama
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Patent number: 4963456Abstract: Electrophotographic toner is provided which contains 30-80% by weight of a polymer per total weight of a resin included in the toner, said polymer is obtained by continuously feeding a vinyl monomer, a polymerization initiator and a solvent into a system of 190.degree.-230.degree. C. to conduct polymerization under a liquid state, and said polymer is a vinyl polymer having a number average molecular weight of 1,000-5,000 and a glass transition temperature of 40.degree.75.degree. C. The preparation method of the electrophotographic toner is also provided. The toner is excellent in the fixing ability at high duplication speed and lower temperatures.Type: GrantFiled: February 22, 1989Date of Patent: October 16, 1990Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Masaaki Shin, Nobuhiro Hirayama, Keiichi Ishikawa, Akira Misawa