Patents by Inventor Koh OHNUMA

Koh OHNUMA 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: 10670980
    Abstract: Provided is a toner including a crystalline polyester resin including a constitutional unit derived from saturated aliphatic dicarboxylic acid and a constitutional unit derived from saturated aliphatic diol, an amorphous hybrid resin, an amorphous polyester resin, a release agent, and a colorant, wherein the crystalline polyester resin includes a constitutional unit derived from sebacic acid as the constitutional unit derived from the saturated aliphatic dicarboxylic acid, and the amorphous hybrid resin is a composite resin including a polyester-based resin unit and a styrene-based resin unit.
    Type: Grant
    Filed: July 10, 2018
    Date of Patent: June 2, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Koh Ohnuma, Tsuyoshi Sugimoto, Shinya Nakayama, Hideyuki Santo, Shin Hasegawa, Suzuka Karato, Kohsuke Nagata
  • Publication number: 20180321606
    Abstract: Provided is a toner including a crystalline polyester resin including a constitutional unit derived from saturated aliphatic dicarboxylic acid and a constitutional unit derived from saturated aliphatic diol, an amorphous hybrid resin, an amorphous polyester resin, a release agent, and a colorant, wherein the crystalline polyester resin includes a constitutional unit derived from sebacic acid as the constitutional unit derived from the saturated aliphatic dicarboxylic acid, and the amorphous hybrid resin is a composite resin including a polyester-based resin unit and a styrene-based resin unit.
    Type: Application
    Filed: July 10, 2018
    Publication date: November 8, 2018
    Inventors: Koh OHNUMA, Tsuyoshi Sugimoto, Shinya Nakayama, Hideyuki Santo, Shin Hasegawa, Suzuka Karato, Kohsuke Nagata
  • Patent number: 10073366
    Abstract: A toner is provided. The toner includes an amorphous resin, a crystalline resin dispersed in the amorphous resin, and a release agent. The toner satisfies the following inequality: B/A<0.8 where A represents a perimeter of the crystalline resin and B represents a length of a part of the perimeter A of the crystalline resin at which the crystalline resin is in contact with the amorphous resin, A and B being measured from a cross-sectional image of the toner observed with transmission electron microscope.
    Type: Grant
    Filed: June 14, 2017
    Date of Patent: September 11, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohsuke Nagata, Ryuuta Yoshida, Shinya Nakayama, Tsuyoshi Sugimoto, Akinori Saitoh, Hideyuki Santo, Suzuka Karato, Koh Ohnuma, Takahiro Kadota, Shinsuke Nagai, Akihiro Takeyama
  • Patent number: 9880479
    Abstract: Toner that includes a polyester resin, fluorine and aluminum. The toner satisfies formulae (1) and (2), 1.00?AB/B?0.50??(1) 0?(A?AB)/A?0.25??(2) where A represents an area where the fluorine exists measured by Energy Dispersive X-ray Spectroscopy (EDS), B represents an area where the aluminum exists measured by Energy Dispersive X-ray Spectroscopy (EDS) and AB represents an overlapping area between A and B. Toner stored unit, image forming apparatus, and image forming method.
    Type: Grant
    Filed: January 12, 2017
    Date of Patent: January 30, 2018
    Assignee: RICOH COMPANY, LTD.
    Inventors: Hideyuki Santoh, Tsuyoshi Sugimoto, Akinori Saitoh, Shin Hasegawa, Suzuka Amemori, Kohsuke Nagata, Koh Ohnuma
  • Publication number: 20170363980
    Abstract: A toner is provided. The toner includes an amorphous resin, a crystalline resin dispersed in the amorphous resin, and a release agent. The toner satisfies the following inequality: B/A<0.8 where A represents a perimeter of the crystalline resin and B represents a length of a part of the perimeter A of the crystalline resin at which the crystalline resin is in contact with the amorphous resin, A and B being measured from a cross-sectional image of the toner observed with transmission electron microscope.
    Type: Application
    Filed: June 14, 2017
    Publication date: December 21, 2017
    Inventors: Kohsuke NAGATA, Ryuuta YOSHIDA, Shinya NAKAYAMA, Tsuyoshi SUGIMOTO, Akinori SAITOH, Hideyuki SANTO, Suzuka KARATO, Koh OHNUMA, Takahiro KADOTA, Shinsuke NAGAI, Akihiro TAKEYAMA
  • Patent number: 9753387
    Abstract: A toner includes a base particle including a polyester resin and a colorant. A sea-island structure is observed by a transmission electron microscope (TEM) in a cross-sectional image of the toner. The island structure includes the colorant and has an average diameter of from 0.2 ?m to 1.0 ?m, and the number of the island structure is from 5 to 30.
    Type: Grant
    Filed: May 12, 2016
    Date of Patent: September 5, 2017
    Assignee: Ricoh Company, Ltd.
    Inventors: Shin Hasegawa, Tsuyoshi Sugimoto, Hideyuki Santo, Koh Ohnuma, Kohsuke Nagata, Suzuka Karato
  • Publication number: 20170199476
    Abstract: Toner that includes a polyester resin, fluorine and aluminum. The toner satisfies formulae (1) and (2), 1.00?AB/B?0.50 ??(1) 0?(A?AB)/A?0.25 ??(2) where A represents an area where the fluorine exists measured by Energy Dispersive X-ray Spectroscopy (EDS), B represents an area where the aluminum exists measured by Energy Dispersive X-ray Spectroscopy (EDS) and AB represents an overlapping area between A and B. Toner stored unit, image forming apparatus, and image forming method.
    Type: Application
    Filed: January 12, 2017
    Publication date: July 13, 2017
    Inventors: Hideyuki SANTOH, Tsuyoshi SUGIMOTO, Akinori SAITOH, Shin HASEGAWA, Suzuka AMEMORI, Kohsuke NAGATA, Koh OHNUMA
  • Patent number: 9639016
    Abstract: A toner includes a polyester resin including a polyester resin component A (A) insoluble in tetrahydrofuran; and a polyester resin component B (B) soluble in tetrahydrofuran. The toner has a first glass transition temperature (Tg1st) of from 20° C. to 50° C., measured at a first temperature rising in differential scanning calorimetry (DSC), and satisfies the following formulae (1) and (2): T=1/{a/(TgA+273)+b/(TgB+273)}?273??(1) T?TgAB>30×a??(2) wherein a and b represent weight ratios of (A) and (B) to a total weight of (A) and (B), and satisfy the equation a+b=1; and TgA, TgB and TgAB represent second glass transition temperatures (Tg2nd), measured at a second temperature rising in differential scanning calorimetry, of (A), (B), and a mixture of (A) and (B), respectively.
    Type: Grant
    Filed: February 23, 2016
    Date of Patent: May 2, 2017
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuyoshi Sugimoto, Shinya Nakayama, Hiroshi Yamada, Hideyuki Santo, Shin Hasegawa, Suzuka Karato, Kohsuke Nagata, Koh Ohnuma
  • Publication number: 20160349644
    Abstract: A toner includes a base particle including a polyester resin and a colorant. A sea-island structure is observed by a transmission electron microscope (TEM) in a cross-sectional image of the toner. The island structure includes the colorant and has an average diameter of from 0.2 ?m to 1.0 ?m, and the number of the island structure is from 5 to 30.
    Type: Application
    Filed: May 12, 2016
    Publication date: December 1, 2016
    Inventors: Shin HASEGAWA, Tsuyoshi SUGIMOTO, Hideyuki SANTO, Koh OHNUMA, Kohsuke NAGATA, Suzuka KARATO
  • Publication number: 20160259257
    Abstract: A toner includes a polyester resin including a polyester resin component A (A) insoluble in tetrahydrofuran; and a polyester resin component B (B) soluble in tetrahydrofuran. The toner has a first glass transition temperature (Tg1st) of from 20° C. to 50° C., measured at a first temperature rising in differential scanning calorimetry (DSC), and satisfies the following formulae (1) and (2): T=1/{a/(TgA+273)+b/(TgB+273)}?273??(1) T?TgAB>30×a??(2) wherein a and b represent weight ratios of (A) and (B) to a total weight of (A) and (B), and satisfy the equation a+b=1; and TgA, TgB and TgAB represent second glass transition temperatures (Tg2nd), measured at a second temperature rising in differential scanning calorimetry, of (A), (B), and a mixture of (A) and (B), respectively.
    Type: Application
    Filed: February 23, 2016
    Publication date: September 8, 2016
    Inventors: Tsuyoshi SUGIMOTO, Shinya NAKAYAMA, Hiroshi YAMADA, Hideyuki SANTO, Shin HASEGAWA, Suzuka KARATO, Kohsuke NAGATA, Koh OHNUMA