Patents by Inventor Ryuta Chiba

Ryuta Chiba 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: 10859932
    Abstract: A toner, including: a polyester resin, wherein the polyester resin has a structure represented by any one of formulas 1) to 3) below: 1) R1-(NHCONH-R2)n-, 2) R1-(NHCOO-R2)n-, and 3) R1-(OCONH-R2)n-, where n is 3 or more, R1 represents an aromatic organic group or an aliphatic organic group, and R2 represents a group derived from a resin that is polyester formed of polycarboxylic acid, polyol, or both thereof; or that is a modified polyester obtained by modifying polyester with isocyanate.
    Type: Grant
    Filed: October 8, 2015
    Date of Patent: December 8, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuyoshi Sugimoto, Shinya Nakayama, Hiroshi Yamada, Hideyuki Santo, Ryuta Chiba, Suzuka Amemori, Kohsuke Nagata
  • Patent number: 10088766
    Abstract: A layered inorganic mineral including a surface treated with a fluorine-containing compound, where the layered inoganic mineral that can be favorably used for a toner that is excellent in high charging ability, charging stability, and low temperature fixing ability, and that can exhibits high reliability during cleaning.
    Type: Grant
    Filed: November 30, 2015
    Date of Patent: October 2, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideyuki Santo, Tsuyoshi Sugimoto, Shinya Nakayama, Suzuka Amemori, Hiroshi Yamada, Ryuta Chiba, Kohsuke Nagata
  • Publication number: 20180024452
    Abstract: A toner, including: a polyester resin, wherein the polyester resin has a structure represented by any one of formulas 1) to 3) below: 1) R1-(NHCONH-R2)n-, 2) R1-(NHCOO-R2)n-, and 3) R1-(OCONH-R2)n-, where n is 3 or more, R1 represents an aromatic organic group or an aliphatic organic group, and R2 represents a group derived from a resin that is polyester formed of polycarboxylic acid, polyol, or both thereof; or that is a modified polyester obtained by modifying polyester with isocyanate.
    Type: Application
    Filed: October 8, 2015
    Publication date: January 25, 2018
    Inventors: Tsuyoshi SUGIMOTO, Shinya NAKAYAMA, Hiroshi YAMADA, Hideyuki SANTO, Ryuta CHIBA, Suzuka AMEMORI, Kohsuke NAGATA
  • Publication number: 20170371257
    Abstract: A layered inorganic mineral including a surface treated with a fluorine-containing compound, where the layered inoganic mineral that can be favorably used for a toner that is excellent in high charging ability, charging stability, and low temperature fixing ability, and that can exhibits high reliability during cleaning.
    Type: Application
    Filed: November 30, 2015
    Publication date: December 28, 2017
    Inventors: Hideyuki SANTO, Tsuyoshi SUGIMOTO, Shinya NAKAYAMA, Suzuka AMEMORI, Hiroshi YAMADA, Ryuta CHIBA, Kohsuke NAGATA
  • Patent number: 9557671
    Abstract: A toner, including: base particles containing a polyester resin, a colorant, and a release agent, wherein the toner has a glass transition temperature (Tg1st) of 20° C. to 50° C. where the glass transition temperature (Tg1st) is measured in first heating of differential scanning calorimetry (DSC) of the toner, wherein tetrahydrofuran (THF) insoluble matter of the toner has a glass transition temperature [Tg2nd (THF insoluble matter)] of 30° C. or lower where the glass transition temperature [Tg2nd (THF insoluble to matter)] is measured in second heating of differential scanning calorimetry (DSC) of the THF insoluble matter, and wherein 50% or less of the colorant is present within a region of 1,000 nm from a surface of each of the base particles toward a center thereof.
    Type: Grant
    Filed: February 24, 2015
    Date of Patent: January 31, 2017
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuta Chiba, Shinya Nakayama, Hiroshi Yamada, Minoru Masuda, Akinori Saitoh, Hideyuki Santo, Shinsuke Nagai, Akihiro Takeyama, Hiroyuki Takeda, Tsuyoshi Sugimoto, Suzuka Amemori, Kohsuke Nagata
  • Patent number: 9488925
    Abstract: A magenta toner for electrophotography, including: a polyester resin; and a colorant containing a naphthol-based pigment, wherein the magenta toner for electrophotography satisfies requirements <1> and <2> below: <1> [G?(100)(THF insoluble matter)] is 1.0×105 Pa to 1.0×107 Pa, and a ratio of [G?(40)(THF insoluble matter)] to the [G?(100)(THF insoluble matter)] is 3.5×10 or less, where the [G?(100)(THF insoluble matter)] is a storage modulus at 100° C. of THF insoluble matter of the toner and the [G?(40)(THF insoluble matter)] is a storage modulus at 40° C. of the THF insoluble matter of the toner; and <2> an X-ray diffraction pattern of the naphthol-based pigment in a crystalline state has a plurality of peaks in a range of 0°?2??35°, and a sum of half value widths of the peaks is 5° to 10°.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: November 8, 2016
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuta Chiba, Shinya Nakayama, Tsuyoshi Sugimoto, Hiroshi Yamada, Susumu Chiba, Shinsuke Nagai, Hiroshi Yamashita, Masana Shiba
  • Publication number: 20150261113
    Abstract: A toner, wherein the toner satisfies a ratio XPS (%)/CIC (ppm) of 1.40×10?2 or less, where CIC (ppm) denotes a fluorine content ratio (ppm) determined by combustion ion chromatography and XPS (%) denotes a fluorine content ratio (%) determined by X-ray photoelectron spectroscopic analysis.
    Type: Application
    Filed: February 24, 2015
    Publication date: September 17, 2015
    Inventors: Akihiro Takeyama, Shinya Nakayama, Hiroshi Yamada, Minoru Masuda, Akinori Saito, Hideyuki Santo, Ryuta Chiba, Hiroyuki Takeda
  • Publication number: 20150253687
    Abstract: A magenta toner for electrophotography, including: a polyester resin; and a colorant containing a naphthol-based pigment, wherein the magenta toner for electrophotography satisfies requirements <1> and <2> below: <1> [G?(100)(THF insoluble matter)] is 1.0×105 Pa to 1.0×107 Pa, and a ratio of [G?(40)(THF insoluble matter)] to the [G?(100)(THF insoluble matter)] is 3.5×10 or less, where the [G?(100)(THF insoluble matter)] is a storage modulus at 100° C. of THF insoluble matter of the toner and the [G?(40)(THF insoluble matter)] is a storage modulus at 40° C. of the THF insoluble matter of the toner; and <2> an X-ray diffraction pattern of the naphthol-based pigment in a crystalline state has a plurality of peaks in a range of 0°?2??35°, and a sum of half value widths of the peaks is 5° to 10°.
    Type: Application
    Filed: February 25, 2015
    Publication date: September 10, 2015
    Inventors: Ryuta Chiba, Shinya Nakayama, Tsuyoshi Sugimoto, Hiroshi Yamada, Susumu Chiba, Shinsuke Nagai, Hiroshi Yamashita, Masana Shiba
  • Publication number: 20150248070
    Abstract: A toner, including: base particles containing a polyester resin, a colorant, and a release agent, wherein the toner has a glass transition temperature (Tg1st) of 20° C. to 50° C. where the glass transition temperature (Tg1st) is measured in first heating of differential scanning calorimetry (DSC) of the toner, wherein tetrahydrofuran (THF) insoluble matter of the toner has a glass transition temperature [Tg2nd (THF insoluble matter)] of 30° C. or lower where the glass transition temperature [Tg2nd (THF insoluble to matter)] is measured in second heating of differential scanning calorimetry (DSC) of the THF insoluble matter, and wherein 50% or less of the colorant is present within a region of 1,000 nm from a surface of each of the base particles toward a center thereof.
    Type: Application
    Filed: February 24, 2015
    Publication date: September 3, 2015
    Inventors: Ryuta CHIBA, Shinya Nakayama, Hiroshi Yamada, Minoru Masuda, Akinori Saitoh, Hideyuki Santo, Shinsuke Nagai, Akihiro Takeyama, Hiroyuki Takeda, Tsuyoshi Sugimoto, Suzuka Amemori, Kohsuke Nagata
  • Patent number: 9023570
    Abstract: A toner contains a binder resin, a colorant, and a releasing agent, wherein the toner contains toner particles, and wherein a proportion of the toner particles containing one or more voids having diameters D1 of larger than 0.0 ?m but 0.5 ?m or smaller is more than 5.0% to 60%, and a proportion of the toner particles containing one or more voids having diameters D2 of 1.0 ?m or larger is 10% or less.
    Type: Grant
    Filed: October 18, 2011
    Date of Patent: May 5, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Masana Shiba, Ryuta Chiba, Tsuneyasu Nagatomo
  • Patent number: 8703375
    Abstract: To provide a toner A containing: base particles, each containing polyester, microcrystalline wax, and a colorant; and spherical silica particles having an average primary particle diameter of 100 nm to 150 nm, wherein the microcrystalline wax has an onset temperature of 45° C. to 60° C. as determined by DSC, and a carbon number distribution of 25 to 55.
    Type: Grant
    Filed: July 22, 2011
    Date of Patent: April 22, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Naohito Shimota, Takahiro Honda, Tsuneyasu Nagatomo, Ryuta Chiba
  • Publication number: 20130216944
    Abstract: A toner contains a binder resin, a colorant, and a releasing agent, wherein the toner contains toner particles, and wherein a proportion of the toner particles containing one or more voids having diameters D1 of larger than 0.0 ?m but 0.5 ?m or smaller is more than 5.0% to 60%, and a proportion of the toner particles containing one or more voids having diameters D2 of 1.0 ?m or larger is 10% or less.
    Type: Application
    Filed: October 18, 2011
    Publication date: August 22, 2013
    Inventors: Masana Shiba, Ryuta Chiba, Tsuneyasu Nagatomo
  • Patent number: 8435716
    Abstract: A method for producing a toner, including: dispersing toner particles containing at least a binder resin in a first aqueous medium so as to produce an aqueous dispersion; and subjecting the aqueous dispersion to heat treatment, wherein the electric conductivity of the aqueous dispersion after the heat treatment is higher than the electric conductivity of the aqueous dispersion before the heat treatment by 50 ?S/cm or less.
    Type: Grant
    Filed: February 4, 2011
    Date of Patent: May 7, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Masaki Watanabe, Osamu Uchinokura, Tsuneyasu Nagatomo, Takahiro Honda, Ryuta Chiba
  • Publication number: 20120021347
    Abstract: To provide a toner A containing: base particles, each containing polyester, microcrystalline wax, and a colorant; and spherical silica particles having an average primary particle diameter of 100 nm to 150 nm, wherein the microcrystalline wax has an onset temperature of 45° C. to 60° C. as determined by DSC, and a carbon number distribution of 25 to 55.
    Type: Application
    Filed: July 22, 2011
    Publication date: January 26, 2012
    Inventors: Naohito Shimota, Takahiro Honda, Tsuneyasu Nagatomo, Ryuta Chiba
  • Publication number: 20110294058
    Abstract: A toner containing a wax, wherein the wax has a mass decrease at 165° C. of 10% by mass or less, a molecular chain consisting of C—H bonds and C—C bonds, and a penetration of 5 mm to 25 mm, wherein a product of a ½ method softening point (° C.) of the toner and an amount of the wax on a surface of the toner is 8 to 20, and wherein the toner is obtained by a method including emulsifying or dispersing in an aqueous medium a toner material liquid, which is a liquid containing a toner material, which contains the wax.
    Type: Application
    Filed: May 24, 2011
    Publication date: December 1, 2011
    Inventors: Masana SHIBA, Takahiro Honda, Tsuneyasu Nagatomo, Naohito Shimota, Ryuta Chiba
  • Publication number: 20110200928
    Abstract: A method for producing a toner, including: dispersing toner particles containing at least a binder resin in a first aqueous medium so as to produce an aqueous dispersion; and subjecting the aqueous dispersion to heat treatment, wherein the electric conductivity of the aqueous dispersion after the heat treatment is higher than the electric conductivity of the aqueous dispersion before the heat treatment by 50 ?S/cm or less.
    Type: Application
    Filed: February 4, 2011
    Publication date: August 18, 2011
    Inventors: Masaki WATANABE, Osamu Uchinokura, Tsuneyasu Nagatomo, Takahiro Honda, Ryuta Chiba