Patents by Inventor Kohtaroh OGINO

Kohtaroh OGINO 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).

  • Publication number: 20240012344
    Abstract: A toner contains an amorphous polyester resin with an SP value of from 11.0 to 11.5 (cal/cm3)1/2, a styrene resin with an SP value of from 9.5 to 10.5 (cal/cm3)1/2, and a hydrocarbon wax, wherein the molecular weight distribution of the toner soluble in tetrahydrofuran has the main peak between 3,500 to 5,500 as measured by gel permeation chromatography.
    Type: Application
    Filed: July 5, 2023
    Publication date: January 11, 2024
    Applicant: Ricoh Company, Ltd.
    Inventors: Kohtaroh OGINO, Yoshitaka YAMAUCHI, Ayaka MORI
  • Publication number: 20230251588
    Abstract: A toner includes: a crystalline polyester resin; and a partially hydrogenated petroleum resin. A hydrogenation rate of the partially hydrogenated petroleum resin is from 30% through 70%. An amount of the partially hydrogenated petroleum resin relative to the toner is from 1% by mass through 15% by mass.
    Type: Application
    Filed: January 25, 2023
    Publication date: August 10, 2023
    Inventors: Ayaka MORI, Yoshitaka YAMAUCHI, Kohtaroh OGINO, Masayuki ISHII
  • Publication number: 20230205107
    Abstract: A toner includes a release agent. The release agent includes a hydrocarbon compound having 2 or more and 16 or less carbon atoms. A content of the hydrocarbon compound having 2 or more and 16 or less carbon atoms, in the release agent, is 1000 ppm or more in terms of toluene, as determined by gas chromatography mass spectrometry. The hydrocarbon compound having 2 or more and 16 or less carbon atoms includes a hydrocarbon compound having a retention time of 7 minutes or more and less than 8 minutes determined by the gas chromatography mass spectrometry.
    Type: Application
    Filed: December 22, 2022
    Publication date: June 29, 2023
    Inventors: Kohtaroh OGINO, Yoshitaka YAMAUCHI, Masayuki ISHII, Ayaka MORI, Kazumi SUZUKI
  • Publication number: 20230205105
    Abstract: A toner including a non-crystalline polyester resin, a crystalline polyester resin, a hydrocarbon wax, and an aromatic petroleum resin is provided. A mass ratio of the aromatic petroleum resin to the hydrocarbon wax is 1.0 or more. The non-crystalline polyester resin contains diol components, and the diol components include an alkylene oxide adduct of bisphenol A and ethylene glycol.
    Type: Application
    Filed: December 15, 2022
    Publication date: June 29, 2023
    Inventors: Yoshitaka YAMAUCHI, Kohtaroh OGINO, Masayuki ISHII, Ayaka MORI
  • Patent number: 11256188
    Abstract: Provided is a toner including toner particles, each toner particle includes: a base particle including a binder resin; and external additive particles, wherein the external additive particles include particles each having an equivalent circle diameter of 10 nm or greater, a volume average particle diameter of the particles each having an equivalent circle diameter of 10 nm or greater is 80 nm or greater but 140 nm or less, and a ratio (circumscribed circle area/particle area) of a circumscribed circle area of the particle having an equivalent circle diameter of 10 nm or greater to a particle area of the particle having an equivalent circle diameter of 10 nm or greater is 1.60 or greater but 2.60 or less.
    Type: Grant
    Filed: December 26, 2018
    Date of Patent: February 22, 2022
    Assignee: RICOH COMPANY, LTD.
    Inventors: Akihiro Kaneko, Kazumi Suzuki, Hisashi Nakajima, Yoshitaka Yamauchi, Kohtaroh Ogino, Teruyuki Suzuki, Namie Suzuki
  • Patent number: 11036156
    Abstract: A toner is provided which includes: a toner base particle including a binder resin; and an external additive including inorganic particles. A particle size distribution of primary particles of the inorganic particles has a plurality of peaks in the range of from 5 nm through 50 nm. The particle size distribution of the primary particles satisfies all of expressions (1) to (3) below: n1d>n2d??(1); 10<(n1d+n2d)??(2); and 30?{(n2h/n1h)×100}<100??(3), where n1d is a particle diameter (nm) at a peak n1 which is the highest peak among the plurality of peaks and n2d is a particle diameter (nm) of a peak n2 which is the second highest peak among the plurality of peaks, and n1h is a height of the peak n1 and n2h is a height of the peak n2.
    Type: Grant
    Filed: January 31, 2020
    Date of Patent: June 15, 2021
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohtaroh Ogino, Masayuki Ishii, Masayuki Kakimoto, Shohichi Sugimoto
  • Publication number: 20210072656
    Abstract: Provided is a toner including toner particles, each toner particle includes: a base particle including a binder resin; and external additive particles, wherein the external additive particles include particles each having an equivalent circle diameter of 10 nm or greater, a volume average particle diameter of the particles each having an equivalent circle diameter of 10 nm or greater is 80 nm or greater but 140 nm or less, and a ratio (circumscribed circle area/particle area) of a circumscribed circle area of the particle having an equivalent circle diameter of 10 nm or greater to a particle area of the particle having an equivalent circle diameter of 10 nm or greater is 1.60 or greater but 2.60 or less.
    Type: Application
    Filed: December 26, 2018
    Publication date: March 11, 2021
    Inventors: Akihiro KANEKO, Kazumi SUZUKI, Hisashi NAKAJIMA, Yoshitaka YAMAUCHI, Kohtaroh OGINO, Teruyuki SUZUKI, Namie SUZUKI
  • Publication number: 20200272067
    Abstract: A toner is provided which includes: a toner base particle including a binder resin; and an external additive including inorganic particles. A particle size distribution of primary particles of the inorganic particles has a plurality of peaks in the range of from 5 nm through 50 nm. The particle size distribution of the primary particles satisfies all of expressions (1) to (3) below: n1d>n2d ??(1); 10<(n1d+n2d) ??(2); and 30{(n2h/n1h)×100}<100 ??(3), where n1d is a particle diameter (nm) at a peak n1 which is the highest peak among the plurality of peaks and n2d is a particle diameter (nm) of a peak n2 which is the second highest peak among the plurality of peaks, and n1h is a height of the peak n1 and n2h is a height of the peak n2.
    Type: Application
    Filed: January 31, 2020
    Publication date: August 27, 2020
    Inventors: Kohtaroh OGINO, Masayuki ISHII, Masayuki KAKIMOTO, Shohichi SUGIMOTO
  • Patent number: 10627732
    Abstract: A toner is provided. The toner includes at least two types of polyester resins and a release agent. When the toner is subjected to a dynamic viscoelasticity measurement at a frequency of 6.28 rad/sec to obtain a temperature-dependent curve of loss tangent (tan ?), and the temperature-dependent curve is differentiated one time with temperature, a resulting curve has a maximum value of 0.07 or more and a minimum value of 0.025 or less within a temperature range of from 85° C. to 110° C. When the toner is subjected to a differential scanning calorimetry (DSC), an endothermic amount measured in a first temperature rising in the DSC is 3.5 J/g or less within a temperature range of from 85° C. to 120° C.
    Type: Grant
    Filed: March 5, 2018
    Date of Patent: April 21, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohtaroh Ogino, Yoshitaka Yamauchi, Akihiro Kaneko, Kazumi Suzuki, Hisashi Nakajima
  • Patent number: 10599059
    Abstract: A toner is provided. The toner comprises mother particles and an external additive covering the mother particles. The mother particles comprise a binder resin, and the external additive comprises inorganic particles. The inorganic particles comprise small-size inorganic particles having an equivalent circle diameter of from 30 to 70 nm and large-size inorganic particles having an equivalent circle diameter of from 150 to 200 nm and a circularity of 0.85 or more. The large-size inorganic particles are 20 to 70 in number per 100 ?m2 image area of the toner observed with a field-emission scanning electron microscope.
    Type: Grant
    Filed: March 6, 2019
    Date of Patent: March 24, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Namie Suzuki, Kazumi Suzuki, Hisashi Nakajima, Yoshitaka Yamauchi, Kohtaroh Ogino, Akihiro Kaneko
  • Publication number: 20200026210
    Abstract: A toner is provided. The toner comprises a binder resin, a metal-containing azo dye, and a quaternary ammonium salt, has an average circularity of from 0.85 to 0.95, and is free of a tin compound having Sn—C bond.
    Type: Application
    Filed: April 30, 2019
    Publication date: January 23, 2020
    Inventors: Yu HIRAI, Masayuki Ishii, Hyo Shu, Masayuki Kakimoto, Yoshitaka Sekiguchi, Shohta Kobayashi, Shinya Hanatani, Kohtaroh Ogino, Yasuaki Iwamoto
  • Publication number: 20190278191
    Abstract: A toner is provided. The toner comprises mother particles and an external additive covering the mother particles. The mother particles comprise a binder resin, and the external additive comprises inorganic particles. The inorganic particles comprise small-size inorganic particles having an equivalent circle diameter of from 30 to 70 nm and large-size inorganic particles having an equivalent circle diameter of from 150 to 200 nm and a circularity of 0.85 or more. The large-size inorganic particles are 20 to 70 in number per 100 ?m2 image area of the toner observed with a field-emission scanning electron microscope.
    Type: Application
    Filed: March 6, 2019
    Publication date: September 12, 2019
    Inventors: Namie SUZUKI, Kazumi SUZUKI, Hisashi NAKAJIMA, Yoshitaka YAMAUCHI, Kohtaroh OGINO, Akihiro KANEKO
  • Patent number: 10310399
    Abstract: Provided is a toner including at least a binder resin, and having peak ratio W/R of from 0.20 to 0.70 when measured with FT-IR according to ATR method, W/R being a ratio of height W of maximum spectral peak attributed to bisphenol A skeleton of the toner and observed at from 1,480 cm?1 to 1,520 cm?1 to height R of maximum spectral peak attributed to carbonyl group of the toner and observed at from 1,700 cm?1 to 1,750 cm?1, wherein molecular weight distribution of the toner obtained by GPC of THF-soluble component of the toner has main peak in a range of from 1,000 to 10,000, half value width of the molecular weight distribution is a molecular weight of 20,000 or less, and content of a THF-insoluble component in the toner is from 5% by mass to 40% by mass.
    Type: Grant
    Filed: November 26, 2015
    Date of Patent: June 4, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Natsuko Matsushita, Tomomi Suzuki, Kohtaroh Ogino, Tohru Moriya
  • Publication number: 20180329326
    Abstract: Provided is a toner including at least a binder resin, and having peak ratio W/R of from 0.20 to 0.70 when measured with FT-IR according to ATR method, W/R being a ratio of height W of maximum spectral peak attributed to bisphenol A skeleton of the toner and observed at from 1,480 cm?1 to 1,520 cm?1 to height R of maximum spectral peak attributed to carbonyl group of the toner and observed at from 1,700 cm?1 to 1,750 cm?1, wherein molecular weight distribution of the toner obtained by GPC of THF-soluble component of the toner has main peak in a range of from 1,000 to 10,000, half value width of the molecular weight distribution is a molecular weight of 20,000 or less, and content of a THF-insoluble component in the toner is from 5% by mass to 40% by mass.
    Type: Application
    Filed: November 26, 2015
    Publication date: November 15, 2018
    Inventors: Natsuko MATSUSHITA, Tomomi SUZUKI, Kohtaroh OGINO, Tohru MORIYA
  • Publication number: 20180267418
    Abstract: A toner is provided. The toner includes at least two types of polyester resins and a release agent. When the toner is subjected to a dynamic viscoelasticity measurement at a frequency of 6.28 rad/sec to obtain a temperature-dependent curve of loss tangent (tan ?), and the temperature-dependent curve is differentiated one time with temperature, a resulting curve has a maximum value of 0.07 or more and a minimum value of 0.025 or less within a temperature range of from 85° C. to 110° C. When the toner is subjected to a differential scanning calorimetry (DSC), an endothermic amount measured in a first temperature rising in the DSC is 3.5 J/g or less within a temperature range of from 85° C. to 120° C.
    Type: Application
    Filed: March 5, 2018
    Publication date: September 20, 2018
    Inventors: Kohtaroh Ogino, Yoshitaka Yamauchi, Akihiro Kaneko, Kazumi Suzuki, Hisashi Nakajima
  • Patent number: 10061220
    Abstract: A toner, containing: a binder resin; and kaolinite, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by gel permeation chromatography (GPC) of THF soluble matter of the toner, and wherein the toner contains the kaolinite in an amount of 5% by mass to 35% by mass.
    Type: Grant
    Filed: July 17, 2015
    Date of Patent: August 28, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohtaroh Ogino, Tohru Moriya, Tomomi Suzuki
  • Patent number: 9904190
    Abstract: A toner, including: a binder resin; and calcium carbonate, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by GPC (gel permeation chromatography) of THF soluble matter of the toner, and wherein the toner contains the calcium carbonate in an amount of 5% by mass to 35% by mass.
    Type: Grant
    Filed: February 2, 2015
    Date of Patent: February 27, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Tatsuya Dan, Tohru Moriya, Tomomi Suzuki, Kohtaroh Ogino
  • Publication number: 20170212442
    Abstract: A toner, containing: a binder resin; and kaolinite, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by gel permeation chromatography (GPC) of THF soluble matter of the toner, and wherein the toner contains the kaolinite in an amount of 5% by mass to 35% by mass.
    Type: Application
    Filed: July 17, 2015
    Publication date: July 27, 2017
    Inventors: Kohtaroh OGINO, Tohru MORIYA, Tomomi SUZUKI
  • Publication number: 20170082933
    Abstract: A toner, including: a binder resin; and calcium carbonate, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by GPC (gel permeation chromatography) of THF soluble matter of the toner, and wherein the toner contains the calcium carbonate in an amount of 5% by mass to 35% by mass.
    Type: Application
    Filed: February 2, 2015
    Publication date: March 23, 2017
    Inventors: Tatsuya DAN, Tohru MORIYA, Tomomi SUZUKI, Kohtaroh OGINO