Patents by Inventor Yasuhiro Shibai
Yasuhiro Shibai 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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Publication number: 20110151369Abstract: Toner having good dispersibility of a pigment and a release agent therein and having excellent low temperature fixability is provided. The toner includes a binder resin, a pigment and a release agent, and the binder resin includes a graft polymer in which abietic acids and a fatty acid are grafted to a polyfunctional epoxy resin. Image is formed using such a toner.Type: ApplicationFiled: December 22, 2010Publication date: June 23, 2011Inventors: Yasuhiro Shibai, Nobuhiro Maezawa
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Publication number: 20110136055Abstract: A toner having good dispersibility of a pigment and a release agent therein and having excellent low temperature fixability is provided. The toner includes a binder resin, a pigment and a release agent, and the binder resin includes a graft polymer in which abietic acids and an unsaturated fatty acid are grafted to a vinyl resin. An image is formed using such a toner.Type: ApplicationFiled: December 2, 2010Publication date: June 9, 2011Inventors: Yasuhiro SHIBAI, Satoru ARIYOSHI
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Patent number: 7955771Abstract: A toner for electrostatic image development, comprising an organic pigment and a binding resin, and satisfying the formula (I): 1?R/A?0.014C??(I), wherein A represents an entire area of a graph (x-axis: wavelength of a visible radiation region (380 to 780 nm), y-axis: transmittance (0 to 100%)) showing a spectral transmittance curve of a supernatant fluid, the supernatant fluid being obtained by subjecting the toner to an extraction process, the extraction process using a supercritical fluid; R represents an area determined by a Rectangular method on the basis of a spectral transmittance curve in the graph; and C represents a concentration (wt %) of the organic pigment in the toner, the organic pigment having a particle diameter of 1/10 to ½ ( 1/10 to 4/7 when the organic pigment is an organic yellow pigment) of a maximum absorption wavelength of the organic pigment, and the toner having a haze of 16 or less.Type: GrantFiled: May 9, 2006Date of Patent: June 7, 2011Assignee: Sharp Kabushiki KaishaInventors: Keiichi Kikawa, Yasuhiro Shibai, Yoritaka Tsubaki
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Patent number: 7931876Abstract: The invention provides a method and an apparatus for manufacturing a developer, which can manufacture a developer having a uniform and fine particle shape in a narrow particle size distribution and having a coloring agent highly dispersed therein at the primary particle level, the method and apparatus at the same time enabling continuous and efficient production without opening and closing a reactor. The method comprises the steps of: dissolving a binding resin component in a supercritical or subcritical fluid so that the binding resin component is blended with a coloring agent component; and reducing the solubility of the binding resin component in the supercritical or subcritical fluid so that the binding resin component is precipitated in the form of particles with the coloring agent component dispersed in the interior thereof.Type: GrantFiled: December 17, 2008Date of Patent: April 26, 2011Assignee: Sharp Kabushiki KaishaInventors: Shinichi Nakano, Yasuhiro Shibai, Keiichi Kikawa
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Publication number: 20110053075Abstract: A toner comprising: a component consisting of a thermoplastic resin containing an amorphous plant-derived resin having a carboxyl group; a component consisting of a crystalline epoxy resin having a glycidyl group; a component consisting of a cross-linked resin generated through a reaction between the carboxyl group of the plant-derived resin and the glycidyl group of the crystalline epoxy resin; and a colorant.Type: ApplicationFiled: August 27, 2010Publication date: March 3, 2011Inventors: Satoru ARIYOSHI, Yasuhiro Shibai
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Patent number: 7875413Abstract: There is provided a capsulated toner which has low-temperature fixing ability, good storage stability, excellent charge stability, high fixing strength to a sheet paper, and low consumption, and is capable of forming a color image of high-definition, high-gloss, and high-density. The capsulated toner for electrophotography includes a shell layer containing a cycloolefin copolymer resin and a core particle including a synthetic resin different from the cycloolefin copolymer resin, wherein the capsulated toner has a core/shell type structure.Type: GrantFiled: May 1, 2007Date of Patent: January 25, 2011Assignee: Sharp Kabushiki KaishaInventors: Yasuhiro Shibai, Katsuru Matsumoto
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Patent number: 7759037Abstract: There are provided a release agent capable of attaining a toner excellent in an anti-offset property and an anti-filming property, without detaching from a kneaded mass even in a case of granulating by heating a dispersion medium containing the kneaded mass, as well as a toner using the release agent and a manufacturing method thereof. A release agent containing a compatible site having compatibility with the binder resin and a releasing site chemically bonded with the compatible site and having the releasing ability is used as the release agent when preparing a kneaded mass by melt-kneading at least a binder resin, a colorant, and a release agent, whereby detachment of the release agent from the kneaded mass can be prevented in producing particles of kneaded mass as the toner particles by mixing the kneaded mass to an aqueous medium prepared and heating and stirring them.Type: GrantFiled: January 12, 2007Date of Patent: July 20, 2010Assignee: Sharp Kabushiki KaishaInventors: Katsuru Matsumoto, Yasuhiro Shibai
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Patent number: 7713675Abstract: There is provided a method of manufacturing a toner, using a shearing force for granulation, in which bubbles are prevented from arising upon application of the shearing force, thus manufacturing a diameter-reduced toner having a particle diameter of about 5 ?m which is favorable for enhancement in definition and resolution of images. Upon granulating after a kneaded product of toner raw material is mixed with water dispersion, an interior part of granulating system is heated and pressurized and moreover, both of the shearing force and collision force are applied to the kneaded product of toner raw material by use of a high-speed rotating dispersion type granulator composed of a cylindrical pressure-resistant container, a spinning rotor, following screens, and a fixed screen.Type: GrantFiled: February 27, 2007Date of Patent: May 11, 2010Assignee: Sharp Kabushiki KaishaInventors: Katsuru Matsumoto, Yasuhiro Shibai, Satoru Ariyoshi
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Patent number: 7704664Abstract: In a method of manufacturing a toner in which toner particles are obtained by mixing resin particles and at least a colorant with each other to be coagulated, and heating an obtained coagulated product, binder resin is granulated into fine particles by a granulating method including a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry containing coarse particles of binder resin obtained by way of the coarse particle preparing step and the slurry preparing step is made to pass under heat and pressure through a pressure-resistant nozzle whereby the coarse particles of binder resin are pulverized into resin particles. By providing the cooling step and the depressurizing step immediately after the pulverizing step, the resin particles are prevented from coarsening.Type: GrantFiled: February 13, 2007Date of Patent: April 27, 2010Assignee: Sharp Kabushiki KaishaInventors: Katsuru Matsumoto, Yasuhiro Shibai
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Patent number: 7687214Abstract: A two-component developer and an image formation method for two-component development type are provided. With this developer and this method, even if toners have a small grain diameter and a high density of pigments for economizing the toner consumption, cracking and toner spent caused by the stress from carriers are suppressed, so that less deteriorated and stabler images can be obtained throughout a long time period. The two-component developer includes toner particles containing at least a binding resin and a pigment. A mean volume particle diameter of the toner particles is between 5.5 ?m and 7 ?m. A number percent of the toner particles with a mean volume particle diameter of 5 ?m or below, and a volume percent of the toner particles with a mean volume particle diameter between 8 ?m and 12.7 ?m, with respect to the total toner particles, respectively, are set to be within a predetermined range. Density of the pigment in the toner particles is between 8 weight percent and 20 weight percent.Type: GrantFiled: October 19, 2005Date of Patent: March 30, 2010Assignee: Sharp Kabushiki KaishaInventors: Yasuhiro Shibai, Yoritaka Tsubaki, Keiichi Kikawa
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Patent number: 7659045Abstract: Resin particles containing at least binding resin and wax particles having a diameter of 30 to 600 nm are coagulated, and a resulting coagulated product is heated. Such wax particles are manufactured, for example, by way of a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry of wax coarse particles obtained by way of the coarse particle preparing step and the slurry preparing step is directed under heat and pressure through a pressure-resistant nozzle whereby the wax coarse particles are pulverized into the wax particles at the pulverizing step. The cooling step and the depressurizing step are disposed just after the pulverizing step to prevent the wax particles from coarsening.Type: GrantFiled: February 13, 2007Date of Patent: February 9, 2010Assignee: Sharp Kabushiki KaishaInventors: Yasuhiro Shibai, Satoru Ariyoshi, Katsuru Matsumoto
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Patent number: 7575843Abstract: A toner is manufactured by way of a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry of toner coarse particles obtained by way of the coarse particle preparing step and the slurry preparing step is made to pass under heat and pressure through a pressure-resistant nozzle whereby toner coarse particles are pulverized into diameter-reduced toner particles. By providing the cooling step immediately after the pulverizing step, dispersion of wax component into the toner particles is promoted. And by further providing the depressurizing step, bubbling and coarsening of the toner particles due to the bubbling are prevented. By so doing, there is obtained a diameter-reduced toner particle in which wax is evenly dispersed and which does not cause bleeding out.Type: GrantFiled: January 12, 2007Date of Patent: August 18, 2009Assignee: Sharp Kabushiki KaishaInventors: Katsuru Matsumoto, Yasuhiro Shibai
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Patent number: 7572566Abstract: According to the method of producing toner, toner is produced by (i) forming particles of a pigmented resin by applying shear stress to a mixture of a pigmented resin composition, an organic solvent, a polymer dispersing agent, and a hydrophobic medium, the organic solvent being capable of reducing viscosity of the pigmented resin composition, and said polymer dispersing agent having a glass transition point in a range of 50° C. to 80° C. and an SP value in a range of 8.5 to 10, (ii) distilling off the organic solvent, and (iii) separating the toner from the hydrophobic medium and drying the toner. With the above arrangement, the method makes it possible to (i) easily downsize toner particle without causing thermal decomposition of a resin or separation of a release agent, and (ii) produce toner that is small in particle size, excellent in humidity-resistance, and less likely to aggregate.Type: GrantFiled: July 20, 2006Date of Patent: August 11, 2009Assignee: Sharp Kabushiki KaishaInventors: Yasuhiro Shibai, Katsuru Matsumoto
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Publication number: 20090117479Abstract: The invention provides a method and an apparatus for manufacturing a developer, which can manufacture a developer having a uniform and fine particle shape in a narrow particle size distribution and having a coloring agent highly dispersed therein at the primary particle level, the method and apparatus at the same time enabling continuous and efficient production without opening and closing a reactor. The method comprises the steps of: dissolving a binding resin component in a supercritical or subcritical fluid so that the binding resin component is blended with a coloring agent component; and reducing the solubility of the binding resin component in the supercritical or subcritical fluid so that the binding resin component is precipitated in the form of particles with the coloring agent component dispersed in the interior thereof.Type: ApplicationFiled: December 17, 2008Publication date: May 7, 2009Applicant: Sharp Kabushiki KaishaInventors: Shinichi Nakano, Yasuhiro Shibai, Keiichi Kikawa
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Publication number: 20090042121Abstract: A toner capable of ensuring cleanness and the amount of specific charge for extended periods of time and having excellent charge stability and fixing property, a two-component developer, a developing device and an image forming apparatus are provided. A toner includes toner particles containing at least a binding resin and a coloring agent, and fine silicon-containing oxide particles having an average primary particle size of not smaller than 70 nm but not larger than 150 nm and containing water in an amount of not larger than 2.0% by weight, the fine silicon-containing oxide particles being externally added to the toner particles.Type: ApplicationFiled: August 8, 2008Publication date: February 12, 2009Inventors: Kiyoshi TOIZUMI, Satoru ARIYOSHI, Yasuhiro SHIBAI
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Publication number: 20090011358Abstract: A method of manufacturing a toner in which uneven distribution of toner ingredients by subjecting them to fine dispersion is prevented and which is excellent in transferability, cleaning properties, anti-filming properties, anti-blocking properties, high-temperature offset resisting properties and transparency is provided. Melt-kneaded substances include binder resins, colorants and release agents, respectively. The colorant and the release agent are dispersed in the binder resin. The melt-kneaded substance is negatively charged by an anionic dispersant, whereas the melt-kneaded substance is positively charged by a cationic dispersant. An aggregate is formed by heteroaggregation of the melt-kneaded substances. The aggregate is fused by heating and formed into a spherical toner.Type: ApplicationFiled: July 2, 2008Publication date: January 8, 2009Inventors: Keiichi Kikawa, Yasuhiro Shibai, Katsuru Matsumoto
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Publication number: 20090011355Abstract: There are provided a toner that allows prevention of environmental contamination and is nevertheless free from toner durability degradation, wherein a sufficiently wide color reproduction range can be secured even when it is applied to color toner, and variation in characteristics among toner particles can be suppressed, as well as a method of manufacturing a toner, a developing device, and an image forming apparatus. In the toner particle is formed the biomass resin-containing domain.Type: ApplicationFiled: July 7, 2008Publication date: January 8, 2009Inventor: Yasuhiro SHIBAI
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Publication number: 20080032224Abstract: A toner in form of aggregate of resin-containing particles is manufactured by aggregating the resin-containing particles which contain binder resin and the colorant, with the aid of an aggregate dispersant containing a polymer in which anionic polar groups are bonded to a main chain. To be specific, salt of divalent or higher valent metal is added to a slurry of the resin-containing particles so that a metal ion and the anionic polar group are bonded to each other, and a temperature of the slurry is increased so that a bond between the anionic polar group and a water molecule is broken. This decreases water-solubility of the polymer so that the resin-containing particles are aggregated.Type: ApplicationFiled: August 1, 2007Publication date: February 7, 2008Inventors: Keiichi Kikawa, Katsuru Matsumoto, Yasuhiro Shibai
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Publication number: 20080014521Abstract: There is provided a toner which can be manufactured in a simple production method and which is excellent in preservation stability and anti-offset property with uniformly-charging performance. The toner is formed of aggregate of resin-containing particles which are obtained by forming amorphous resin particles into slurry and further finely granulating the amorphous resin particles in form of the slurry followed by aggregation of the amorphous resin particles and which contains a binder resin, a colorant, a release agent, and a release agent-dispersing aid, the resin-containing particles having a volume average particle diameter in a range of from 0.4 ?m to 1.0 ?m.Type: ApplicationFiled: July 11, 2007Publication date: January 17, 2008Applicant: SHARP KABUSHIKI KAISHAInventors: Yoritaka Tsubaki, Yasuhiro Shibai
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Publication number: 20070259284Abstract: There is provided a capsulated toner which has low-temperature fixing ability, good storage stability, excellent charge stability, high fixing strength to a sheet paper, and low consumption, and is capable of forming a color image of high-definition, high-gloss, and high-density. The capsulated toner for electrophotography includes a shell layer containing a cycloolefin copolymer resin and a core particle including a synthetic resin different from the cycloolefin copolymer resin, wherein the capsulated toner has a core/shell type structure.Type: ApplicationFiled: May 1, 2007Publication date: November 8, 2007Applicant: SHARP KABUSHIKI KAISHAInventors: Yasuhiro Shibai, Katsuru Matsumoto