Patents by Inventor Kazuoki Fuwa
Kazuoki Fuwa 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: 20120328976Abstract: A toner including: a base resin; and charge-controlling resin particles contained in the base resin, wherein the toner is in shape of particles, and the charge-controlling resin particles are present in a region of each toner particle which is 500 nm in depth from a surface of the toner particle and an average of amounts of the charge-controlling resin particles present in the regions of the toner particles is 20% by volume to 70% by volume, wherein an average of embedment rates of the charge-controlling resin particles in the toner particles is 90% or higher, where each embedment rate is an average of embedment rates of the charge-controlling resin particles in each toner particle, and wherein the charge-controlling resin particles have a charge amount of 60 ?C/m2 or more as measured by a blow-off method.Type: ApplicationFiled: June 18, 2012Publication date: December 27, 2012Inventors: Masahiro Seki, Yoshitaka Sekiguchi, Ryota Inoue, Kazuoki Fuwa
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Patent number: 8329371Abstract: A non-magnetic toner, including a binder resin; a wax present dispersing in the toner in the shape of a particle; and a colorant, wherein the wax having a particle diameter not less than 2.0 ?m and less than 3.0 ?m is not less than 20% and less than 40% by number based on total number thereof; the wax has a mode value not less than 1.5 ?m and less than 2.0 ?m in a frequency distribution of 0.1 ?m width; and the following relationship is satisfied: 45<XZ/Y<62 wherein X represents a softening point (° C.) of the toner; Y represents a volume-average particle diameter (?m) of the toner; and Z represents a total parts by weight of the wax included in 100 parts by weight of the toner.Type: GrantFiled: December 21, 2007Date of Patent: December 11, 2012Assignee: Ricoh Company, Ltd.Inventors: Yoshihiro Mikuriya, Hideaki Yasunaga, Hiroaki Katoh, Kazuoki Fuwa, Masayuki Hagi, Masahide Inoue
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Publication number: 20120264048Abstract: Provided is a toner including: toner particles, each toner particle containing a toner base particle, wherein the toner contains a binder resin; and a colorant, wherein the toner base particle has protrusions at a surface thereof, wherein an average of lengths of long sides of the protrusions is 0.1 ?m or more but less than 0.5 ?m, a standard deviation of the lengths of the long sides of the protrusions is 0.20 or less, and a coverage rate of the protrusions is 30% to 90%, wherein a resin forming the protrusions is prepared through polymerization of a monomer mixture containing at least a monomer having a sulfonic acid group, and wherein the monomer mixture contains styrene in an amount of 90% by mass or more and the monomer having a sulfonic acid group in an amount of 0.1% by mass to 5% by mass.Type: ApplicationFiled: April 10, 2012Publication date: October 18, 2012Inventors: Yoshimichi ISHIKAWA, Takuya KADOTA, Yoshihiro MIKURIYA, Tsuyoshi NOZAKI, Kazuoki FUWA, Tomohiro FUKAO, Tomoharu MIKI, Atsushi YAMAMOTO
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Publication number: 20120251938Abstract: A method for producing colored resin particles including: dissolving or dispersing at least binder resin and colorant in organic solvent to prepare oil phase; dissolving resin A and basic compound in aqueous medium to prepare aqueous phase, the resin A having solubility <2.0 g/100 g water having temperature 25° C. and pH 3.0 and solubility ?2.0 g/100 g water having temperature 25° C. and pH 10.0; dispersing the oil phase in the aqueous phase to prepare core particle dispersion liquid; dispersing resin particles in aqueous medium to prepare resin particle dispersion liquid, and adding the resin particle dispersion liquid to the core particle dispersion liquid so that the resin particles are attached onto the core particles, to prepare dispersion liquid containing particles each having the core particle and the resin particles attached thereonto; removing the organic solvent from the dispersion liquid; washing the particles; and drying the particles.Type: ApplicationFiled: February 1, 2012Publication date: October 4, 2012Inventors: Atsushi Yamamoto, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki
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Publication number: 20120237267Abstract: An electrostatic image developing toner including: toner particles each containing binder resin and colorant; and an external additive supported on the toner particles, wherein the toner particles each have protrusions on surface thereof, average of lengths of long sides of the protrusions is 0.10 ?m or more but less than 0.50 ?m, standard deviation of the lengths of the long sides of the protrusions is 0.20 or less, coverage rate of the protrusions on the surface of each toner particle is 30% to 90%, the external additive includes at least two different particles including external additive (A) and one or more external additives (B), external additive (A) has longest average primary particle diameter among the external additives and charged to have the opposite polarity to the toner particles, and at least one of the external additives (B) is charged to have the same polarity as the toner particles.Type: ApplicationFiled: March 16, 2012Publication date: September 20, 2012Inventors: Tomohiro FUKAO, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomoharu Miki
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Publication number: 20120237253Abstract: An electrostatic image developing toner including: toner particles; wherein the toner particles each contain: a core particle including a first resin and a colorant; and fine resin particles each formed of a second resin and existing in a surface of the core particle, wherein part of each fine resin particle is embedded in the core particle to form an embedded region, and the remaining part of the fine resin particle is exposed on the surface of the core particle to form an exposed region, and wherein each toner particle satisfies an expression of R1>R1? where, in a cross-section of the toner particle, R1? denotes an average diameter of openings of the first resin in which the second resin is embedded and R1 denotes an average diameter of the exposed regions.Type: ApplicationFiled: March 12, 2012Publication date: September 20, 2012Inventors: Tomohiro FUKAO, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomoharu Miki
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Publication number: 20120219321Abstract: A toner including a binder resin, a colorant and protruding portions on a surface of the toner, wherein the average length of long sides of the protruding portions is 0.1 ?m or greater, but less than 0.5 ?m, wherein the standard deviation of the lengths of the long sides of the protruding portions is 0.2 or less, and wherein the protruding portions have a coverage of 30% to 90%.Type: ApplicationFiled: October 27, 2010Publication date: August 30, 2012Inventors: Tomohiro Fukao, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Atsushi Yamamoto, Tomoharu Miki, Kazuoki Fuwa
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Patent number: 8192910Abstract: An image forming method, including charging the surface of an electrostatic latent image bearer by a charger; irradiating the surface of the electrostatic latent image bearer to form an electrostatic latent image thereon; developing the same with a toner to form a toner image; transferring the toner image onto a recording medium; and fixing the toner image thereon, wherein the charger is a charging roller contacting the electrostatic latent image bearer to charge the same, having a ten-point surface roughness of 5 to 30, and the toner includes a binder resin, a colorant, a release agent and an external additive including a composite oxide including titanium oxide in an amount of 80 to 95% by weight and silicon oxide, having a core-shell structure formed of a core including the titanium oxide and a shell including the silicon oxide and has a BET specific surface area of 50 to 100 m2/g.Type: GrantFiled: June 24, 2009Date of Patent: June 5, 2012Assignee: Ricoh Company, LimitedInventors: Hiroaki Katoh, Naoki Nakatake, Masayuki Hagi, Yoshitaka Sekiguchi, Kazuoki Fuwa, Yoshihiro Mikuriya, Hideaki Yasunaga
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Patent number: 8103199Abstract: A developing device including a developing roller facing an image bearing member and a toner layer thickness control member to control an amount of a toner adhered to the developing roller, so that an electrostatic latent image formed on the image bearing member is developed with the toner to form a toner image. The following relationships are satisfied: 0.08×100.3×Dv<Ra<0.18×100.3×Dv, 2.0<(Ra/RSm)×100<4.0, and 8<Rz<15, where Dv (?m) is a volume average particle diameter of the toner, Ra (?m) is an arithmetical mean roughness of the developing roller in a longitudinal direction, Rz (?m) is a ten-point mean roughness of the developing roller in a longitudinal direction, and RSm (?m) is a mean length of roughness curve elements of the developing roller.Type: GrantFiled: January 24, 2008Date of Patent: January 24, 2012Assignee: Ricoh Company LimitedInventors: Hideaki Yasunaga, Masayuki Hagi, Yoshihiro Mikuriya, Yoshitaka Sekiguchi, Hiroaki Katoh, Kazuoki Fuwa, Masahide Inoue
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Publication number: 20110287356Abstract: An electrostatic image developing toner including toner core particles each containing at least a first resin and a colorant, and fine resin particles formed of a second resin, wherein part of each of the fine resin particles is embedded in each of the toner core particles, and the remaining part of the fine resin particle is exposed on a surface of the toner core particle to form a protrusion, and wherein when a rate of the part of the fine resin particle to the fine resin particle is indicated by an embedment rate, an average of the embedment rates in the fine resin particles is 40% to 80%.Type: ApplicationFiled: May 23, 2011Publication date: November 24, 2011Inventors: Tomohiro Fukao, Takuya Kadota, Chieko Yamazaki, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Atsushi Yamamoto, Kazuoki Fuwa, Tomoharu Miki
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Patent number: 8041270Abstract: An image developer using a one-component developer, Including a developing roller visualizing an electrostatic latent image formed on an image bearer with a pulverized toner; and a feed roller feeding the pulverized toner to the developing roller while contacting thereto, wherein the pulverized toner includes a parent toner; a wax; and an external additive comprising an additive having a number-average particle diameter of from 20 to 60 nm and adhering to the surface of the parent toner at an adherence strength of from 50 to 70%, and wherein the following relationships (1) to (3) are satisfied: 4.70<Log10 R<5.70??(1) 8.00<Log10 Z<10.70??(2) ?6.25*Log10 R+37.5<Log10 Z<?6.25*Log10 R+45.6??(3) wherein R represents a resistivity of the developing roller and Z represents an impedance of the pulverized toner.Type: GrantFiled: March 14, 2008Date of Patent: October 18, 2011Assignee: Ricoh Company, LimitedInventors: Hideaki Yasunaga, Masayuki Hagi, Yoshihiro Mikuriya, Hiroaki Katoh, Kazuoki Fuwa, Masahide Inoue, Yoshitaka Sekiguchi, Satoshi Ogawa
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Publication number: 20110250533Abstract: To provide a toner for an electrostatic image developer, including: a core particle obtained by dispersing, in an aqueous medium, an oil phase prepared by dissolving or dispersing at least a binder resin, a colorant and a release agent in an organic solvent; and a shell layer formed of vinyl resin fine particles present on a surface of the core particle, wherein the shell layer has protruding portions formed of the vinyl resin fine particles, and wherein the vinyl resin fine particles contain 80% by mass or more of an aromatic compound which has a vinyl-polymerizable functional group, and a vinyl resin which forms the vinyl resin fine particles has a weight average molecular weight of 8,000 to 16,000.Type: ApplicationFiled: April 11, 2011Publication date: October 13, 2011Inventors: Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Atsushi Yamamoto, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki
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Patent number: 8021814Abstract: A toner useful for an oilless fixing method, includes a binder resin; a colorant; and 2.0 to 4.5% by weight of a wax which is soluble in n-hexane, based on a total weight of the toner, wherein the wax is dispersed in the toner, the wax forming wax domain particles (DA) comprising wax domain particles (DS) exposed at a surface of the toner and wax domain particles (DI) encapsulated in the toner and not exposed at the surface of the toner, wherein a weight of the DS is greater than a weight of the DI, wherein the toner from which the DS have been eluted with n-hexane comprises vestigial concavities having an area of 0.01 ??m2 or more on the surface of the toner in an amount of from 1 to 7 pcs/4 ?m2, and wherein 60% or more by number of the DA having a particle diameter of 200 nm or more have a spindle or cylindrical shape having an aspect ratio of 4 or more.Type: GrantFiled: March 19, 2008Date of Patent: September 20, 2011Assignee: Ricoh Company LimitedInventors: Masayuki Hagi, Yoshihiro Mikuriya, Hideaki Yasunaga, Hiroaki Katoh, Kazuoki Fuwa, Yoshitaka Sekiguchi, Satoshi Ogawa, Masahide Inoue
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Patent number: 8007973Abstract: A full-color toner kit including yellow, magenta, and cyan toners each including a benzimidazolone, a naphthol, and a copper phthalocyanine colorants, respectively, and resins (A) and (B) each of which having a polyester skeleton and containing a wax, and a resin (C) having a polyester skeleton and containing no wax. Each of the toners has a softening point of from 125° C. to 135° C. The following relationships are satisfied: Ts(A)<Ts(B), Ay+5?Am?Ay+15, and Ac+5?Am?Ac+15, wherein Ts(A) and Ts(B) (° C.) each represent softening points of the resin (A) and (B), respectively, and Ay, Am, and Ac each represent ratios (% by weight) of the amount of the resin (A) to total amount of the resins (A) and (B) in the yellow, magenta, cyan toners, respectively.Type: GrantFiled: December 27, 2007Date of Patent: August 30, 2011Assignee: Ricoh Company, LimitedInventors: Kazuoki Fuwa, Yoshihiro Mikuriya, Masayuki Hagi, Hideaki Yasunaga, Hiroaki Katoh, Yoshitaka Sekiguchi
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Patent number: 7981593Abstract: A toner including toner particles including a resin, a colorant, a wax, and a charge controlling agent, and an external additive, wherein the toner satisfies the relationships (1) 0.15×Q?2?T?0.15×Q?0.15, and (2) 1.0?T?2.5, wherein Q represents the charge of the toner in units of ?C/g, and T represents the torque of the toner in units of mN·m determined by a method using a cone-shaped rotor while controlling a space ratio of the toner at 58%. A developer including the toner and a carrier. An image forming apparatus including an image bearing member, a transfer device, a fixing device and a double side image forming unit, and using the toner, wherein the receiving material includes moisture in an amount of not greater than 5% by weight after the toner image on the first side is fixed.Type: GrantFiled: September 14, 2007Date of Patent: July 19, 2011Assignee: Ricoh Company LimitedInventors: Hiroaki Katoh, Hideaki Yasunaga, Kazuoki Fuwa, Yoshihiro Mikuriya, Masayuki Hagi, Masahide Inoue
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Patent number: 7979010Abstract: Provided is an image forming apparatus including at least a latent image bearing member, a latent electrostatic image forming unit, a developing unit which includes at least a developing roller and a supply roller, and a transfer unit, wherein both of a diameter R (mm) of the developing roller and a diameter R? (mm) of the supply roller are 12 mm or less; the toner contains at least a binder resin, a wax, and a colorant with the wax having a melting point of 75° C. or less; an amount of the wax exposed on a surface of the toner is 10 mg/g to 30 mg/g; and when a diameter (mm) of the developing roller is represented by R the toner has a torque T (mNm) satisfying the inequation, 20/R<T<27/R, at a void rate of 58% as measured by a torque measurement method using a conical rotor.Type: GrantFiled: December 23, 2008Date of Patent: July 12, 2011Assignee: Ricoh Company, Ltd.Inventors: Kazuoki Fuwa, Yoshihiro Mikuriya, Hideaki Yasunaga, Yoshitaka Sekiguchi, Hiroaki Kato
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Publication number: 20110164901Abstract: A toner containing core particles each containing at least a resin A having a polyester skeleton and a colorant; and vinyl resin fine particles each of which encapsulates a resin B having at least a polyester skeleton and an endothermic peak measured by differential scanning calorimeter (DSC) at 40° C. to 110° C., wherein the vinyl resin fine particles are attached onto each of the core particles.Type: ApplicationFiled: December 6, 2010Publication date: July 7, 2011Inventors: Atsushi YAMAMOTO, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki, Masayuki Hagi
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Patent number: 7970323Abstract: A developing device including a developer bearing member configured to feed a developer to an image bearing member; a developer supplying member, which is contacted with the developer bearing member at a first nip while opposed thereto and which is configured to supply the developer to the developer bearing member; and a developer layer forming member, which is contacted with the developer bearing member at a second nip located on the downstream side from the first nip relative to the rotation direction of the developer bearing member to form the layer of the developer on the developer bearing member, wherein the developer is a nonmagnetic one component developer, and the distance between the front edge of the second nip and the rear edge of the first nip relative to the rotation direction of the image bearing member is greater than 0.8 mm and less than 2.0 mm.Type: GrantFiled: March 5, 2008Date of Patent: June 28, 2011Assignee: Ricoh Company, Ltd.Inventors: Hiroaki Katoh, Masayuki Hagi, Yoshihiro Mikuriya, Hideaki Yasunaga, Yoshitaka Sekiguchi, Kazuoki Fuwa, Masahide Inoue
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Publication number: 20110053077Abstract: The present invention provides a method for producing a colored resin particle, the method including: preparing an oil phase in which at least a resin and a colorant are dissolved or dispersed in an organic solvent; preparing an aqueous phase containing at least a surfactant in an aqueous medium; dispersing the oil phase in the aqueous phase to prepare a colored particle dispersion liquid so as to form core particles; causing resin fine particles to adhere to surfaces of the core particles by adding at least the resin fine particles to the colored particle dispersion liquid, in which the core particles have been formed; removing the solvent from the colored particle dispersion liquid to obtain colored resin particles, washing the colored resin particles, and drying the colored resin particles, wherein an inorganic base is dissolved in the colored particle dispersion liquid.Type: ApplicationFiled: August 27, 2010Publication date: March 3, 2011Inventors: Yoshihiro MIKURIYA, Tomoharu Miki, Tomohiro Fukao, Kazuoki Fuwa, Takuya Kadota, Yoshimichi Ishikawa, Atsushi Yamamoto, Tsuyoshi Nozaki
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Patent number: 7873300Abstract: A single component development device including a toner including a resin, a coloring agent, a wax, a charge control agent and an inorganic particulate, a development roller to bear the toner on the surface of the development roller and transfer the toner to an image bearing member and a thin layer forming member to regulate a thickness of the layer of the toner while in contact with the surface of the development roller via the toner borne thereon, wherein a regulating pressure A between the thin layer forming member and the development roller is from 25 to 60 (N/m), a content Z (weight %) of the charge control agent satisfies the following relationship (1) and an average dispersion particle diameter D (nm) of the charge control agent satisfies the following relationship (2): 0.029×A?0.150>Z>0.013×A?0.013??Relationship (1) D<6.3×A?106.3??Relationship (2).Type: GrantFiled: August 5, 2008Date of Patent: January 18, 2011Assignee: Ricoh Company LimitedInventors: Kazuoki Fuwa, Masayuki Hagi, Yoshihiro Mikuriya, Hideaki Yasunaga, Hiroaki Katoh, Yoshitaka Sekiguchi, Satoshi Ogawa