Patents by Inventor Yoshitaka Sekiguchi

Yoshitaka Sekiguchi 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: 20210009799
    Abstract: A resin composition is provided. The resin composition comprises an acrylonitrile butadiene styrene resin, a polystyrene resin, a polycarbonate resin, and a phosphorus compound. The amount of the polystyrene resin is equal to or greater than the amount of the acrylonitrile butadiene styrene resin. The amount of the polycarbonate resin is from 70 to 90 parts by mass with respect to 100 parts by mass of all the resins. The phosphorus compound contains a phosphazene compound, and the amount of the phosphazene compound is from 0.1 to 4.0 parts by mass with respect to 100 parts by mass of all the resins.
    Type: Application
    Filed: June 22, 2020
    Publication date: January 14, 2021
    Inventors: Natsuki KOIKE, Yasushi AKIBA, Mitsuyo MATSUMOTO, Yoshitaka SEKIGUCHI
  • Patent number: 10754270
    Abstract: Provided is a toner including a binder resin, and a charge-controlling agent, wherein a volume average particle diameter X of the toner after a stress treatment satisfies Formula (1), and an amount Y of fine toner particles having particle diameters of 3 micrometers or smaller and circularity of 0.70 or less satisfies Formula (2).
    Type: Grant
    Filed: February 15, 2018
    Date of Patent: August 25, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoko Kitada, Satoshi Ogawa, Yoshitaka Sekiguchi, Masayuki Ishii, Shohta Kobayashi
  • Publication number: 20200174390
    Abstract: Provided is a toner including a binder resin, and a charge-controlling agent, wherein a volume average particle diameter X of the toner after a stress treatment satisfies Formula (1), and an amount Y of fine toner particles having particle diameters of 3 micrometers or smaller and circularity of 0.70 or less satisfies Formula (2).
    Type: Application
    Filed: February 15, 2018
    Publication date: June 4, 2020
    Inventors: Naoko KITADA, Satoshi OGAWA, Yoshitaka SEKIGUCHI, Masayuki ISHII, Shohta KOBAYASHI
  • 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: 20200019076
    Abstract: Provided is a toner including a binder resin, a release agent, and a charge-controlling agent, wherein the toner includes toner particles having particle diameters of 3 micrometers or smaller, among the toner particles having particle diameters of 3 micrometers or smaller, a proportion of the toner particles having an average circularity of 0.70 or greater but 0.85 or less in all of the toner particles is 10% by number or greater but less than 20% by number and a proportion of the toner particles having an average circularity of less than 0.70 in all of the toner particles is 10% by number or less.
    Type: Application
    Filed: February 21, 2018
    Publication date: January 16, 2020
    Inventors: Shohta KOBAYASHI, Satoshi OGAWA, Yoshitaka SEKIGUCHI, Masayuki ISHII, Naoko KITADA
  • Patent number: 10274856
    Abstract: A toner for electrophotography, which contains a binder resin, and a release agent, wherein a maximum value of loss tangent of the toner at 95° C. to 115° C. is 8 or greater, as a viscoelasticity of the toner is measured, where the loss tangent is represented by the following formula: Loss tangent (tan ?)=loss elastic modulus (G?)/storage elastic modulus (G?).
    Type: Grant
    Filed: January 6, 2015
    Date of Patent: April 30, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Hisashi Nakajima, Kazumi Suzuki, Masashi Nagayama, Saori Yamada, Yoshitaka Yamauchi, Yu Naito, Yoshitaka Sekiguchi
  • Publication number: 20190011847
    Abstract: Provided is a toner including a binder resin, wherein the toner includes a THF-insoluble component in an amount of from 10% by mass through 40% by mass, a molecular weight distribution of a THF-soluble component of the toner measured by gel permeation chromatography (GPC) has a main peak between 10,000 and 16,000, and a half value width of the main peak is a molecular weight of from 60,000 through 90,000, and the THF-soluble component of the toner includes a component having a molecular weight of 2,000 or less in an amount of from 15.0% by mass through 25.0% by mass, and a component having a molecular weight of 100,000 or greater in an amount of 10.0% by mass or less as measured by GPC.
    Type: Application
    Filed: September 14, 2018
    Publication date: January 10, 2019
    Inventors: Satoshi OGAWA, Masahiro SEKI, Yoshitaka SEKIGUCHI, Tohru MORIYA
  • Patent number: 10025213
    Abstract: A toner including a binder resin, wherein the toner includes a tetrahydrofuran (THF)-insoluble component in a range of from 10% by mass through 40% by mass, wherein the toner has a main peak in a range of from 12,000 through 18,000 in a molecular weight distribution of a THF-soluble component as measured by gel permeation chromatography (GPC), wherein the main peak has a half value width in a range of from 20,000 to 50,000, and wherein the toner includes a component having a molecular weight of 2,000 or less in a range of from 10.0% by mass through 20.0% by mass and a component having a molecular weight of 100,000 or more of 8.0% by mass or less.
    Type: Grant
    Filed: February 29, 2016
    Date of Patent: July 17, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiro Seki, Yoshitaka Sekiguchi, Satoshi Ogawa, Naoko Kitada
  • Publication number: 20180031992
    Abstract: A toner including a binder resin, wherein the toner includes a tetrahydrofuran (THF)-insoluble component in a range of from 10% by mass through 40% by mass, wherein the toner has a main peak in a range of from 12,000 through 18,000 in a molecular weight distribution of a THF-soluble component as measured by gel permeation chromatography (GPC), wherein the main peak has a half value width in a range of from 20,000 to 50,000, and wherein the toner includes a component having a molecular weight of 2,000 or less in a range of from 10.0% by mass through 20.0% by mass and a component having a molecular weight of 100,000 or more of 8.0% by mass or less.
    Type: Application
    Filed: February 29, 2016
    Publication date: February 1, 2018
    Inventors: Masahiro SEKI, Yoshitaka SEKIGUCHI, Satoshi OGAWA, Naoko KITADA
  • Publication number: 20160327884
    Abstract: A toner for electrophotography, which contains a binder resin, and a release agent, wherein a maximum value of loss tangent of the toner at 95° C. to 115° C. is 8 or greater, as a viscoelasticity of the toner is measured, where the loss tangent is represented by the following formula: Loss tangent (tan ?)=loss elastic modulus (G?)/storage elastic modulus (G?).
    Type: Application
    Filed: January 6, 2015
    Publication date: November 10, 2016
    Inventors: Hisashi NAKAJIMA, Kazumi SUZUKI, Masashi NAGAYAMA, Saori YAMADA, Yoshitaka YAMAUCHI, Yu NAITO, Yoshitaka SEKIGUCHI
  • Patent number: 9448501
    Abstract: A toner for developing an electrostatic image, which contains: resin particles (C), wherein the resin particles (C) each contain a resin particle (B) and resin particles (A) or a coating film (P) deposited on a surface of the resin particle (B), where the resin particle (B) contains a second resin (b) and a filler (f), wherein the resin particles (A) or the coating film (P) contains a first resin (a), wherein the second resin (b) contains a crystalline resin, and wherein the resin particle (B) contains the filler (f) in an amount of 15% by mass or greater.
    Type: Grant
    Filed: February 7, 2013
    Date of Patent: September 20, 2016
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Yoshitaka Sekiguchi, Hiroaki Katoh, Shun Saito
  • Patent number: 9348259
    Abstract: A toner housing container includes a container body housing a toner; a conveying portion conveying the toner from one end of the container body, in a longer direction of the container body, to its other end at which a container opening portion is provided; a pipe receiving port receiving a conveying pipe fixed to a toner conveying device; and an uplifting portion moving the toner toward a toner receiving port of conveying pipe. Such toner has a molecular weight distribution having a peak in a range of 103 to 104, and has C/R of from 0.03 to 0.55 between peak height C attributed to crystalline polyester resin and R attributed to non-crystalline resin when measured by FT-IR after stored at 45° C. for 12 hours.
    Type: Grant
    Filed: May 15, 2014
    Date of Patent: May 24, 2016
    Assignee: RICOH COMPANY, LTD.
    Inventors: Masashi Nagayama, Hisashi Nakajima, Yoshitaka Sekiguchi, Saori Yamada, Shinya Hanatani, Mariko Takii, Hiroshi Hosokawa, Shunji Katoh, Shinji Tamaki, Hiroshi Ikeguchi, Kenji Kikuchi, Michiharu Suzuki
  • Patent number: 9182694
    Abstract: A toner, including: a binder resin; and a colorant, wherein the binder resin contains: a crystalline polyester resin (A); a non-crystalline resin (B); and a composite resin (C), where the composite resin (C) contains a condensation polymerization resin unit and an addition polymerization resin unit, wherein the toner contains chloroform insoluble matter in an amount of 1% by mass to 30% by mass, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000 and a half width of 15,000 or less, where the molecular weight distribution is obtained through gel permeation chromatography (GPC) of tetrahydrofuran soluble matter of the toner, and wherein the toner has an endothermic peak in a range of 90° C. to 130° C. in measurement through differential scanning calorimetry (DSC).
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: November 10, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Saori Yamada, Hisashi Nakajima, Masashi Nagayama, Shinya Hanatani, Mariko Takii, Yoshitaka Sekiguchi
  • Patent number: 9152066
    Abstract: A toner, including: a binder resin; releasing agent-encapsulating capsules; and a colorant, wherein the releasing agent-encapsulating capsules each include: a capsule formed of a resin (I) which is different from the binder resin; and a releasing agent (RA) which is encapsulated in the capsule, and the releasing agent-encapsulating capsules exist in the binder resin, and wherein 50% to 100% of the releasing agent-encapsulating capsules exist in a region from a surface of the toner to a depth of 0.10 times a volume-average particle diameter of the toner.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: October 6, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Hiroaki Katoh, Masahiro Seki, Shun Saito, Yoshitaka Sekiguchi, Yoshihiro Mikuriya, Kazuoki Fuwa, Satoshi Ogawa, Tomohiro Fukao, Takayuki Nakamura
  • Patent number: 9005862
    Abstract: A toner including a crystalline polyester resin (A), an amorphous resin (B), and a composite resin (C) having a condensation polymerization resin unit and an addition polymerization resin unit is provided. A molecular weight distribution of the toner based on THF-soluble contents thereof has a main peak within a molecular weight range from 1,000 to 10,000 and a half bandwidth of the main peak is 15,000 or less. The molecular weight distribution is determined by gel permeation chromatography. The toner includes chloroform-insoluble contents. A ratio C/R of the toner is within a range from 0.03 to 0.55. C and R represent heights of spectrum peaks specific to the crystalline polyester resin (A) and the amorphous resin (B), respectively, determined by a Fourier transform infrared spectroscopic attenuation total reflection method after the toner is stored in a thermostatic chamber at 45° C. for 12 hours.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: April 14, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Masashi Nagayama, Hisashi Nakajima, Saori Yamada, Shinya Hanatani, Mariko Takii, Yoshitaka Sekiguchi
  • Publication number: 20140363209
    Abstract: A toner for developing an electrostatic image, which contains: resin particles (C), wherein the resin particles (C) each contain a resin particle (B) and resin particles (A) or a coating film (P) deposited on a surface of the resin particle (B), where the resin particle (B) contains a second resin (b) and a filler (f), wherein the resin particles (A) or the coating film (P) contains a first resin (a), wherein the second resin (b) contains a crystalline resin, and wherein the resin particle (B) contains the filler (f) in an amount of 15% by mass or greater.
    Type: Application
    Filed: February 7, 2013
    Publication date: December 11, 2014
    Inventors: Ryota Inoue, Yoshitaka Sekiguchi, Hiroaki Katoh, Shun Saito
  • Publication number: 20140348550
    Abstract: Toner housing container includes: container body housing a toner; conveying portion conveying the toner from longer direction one end of container body to its other end at which container opening portion is provided; pipe receiving port receiving a conveying pipe fixed to toner conveying device; and uplifting portion moving the toner toward toner receiving port of conveying pipe. Toner has molecular weight distribution having a peak in a range of 103 to 104, and has C/R of from 0.03 to 0.55 between peak height C attributed to crystalline polyester resin and R attributed to non-crystalline resin when measured by FT-IR after stored at 45° C. for 12 hours. Container body includes protruding portion protruding from container body interior side toward the one end. Uplifting portion includes uplifting wall surface extending from container body internal wall surface toward protruding portion. Protruding portion is present between uplifting wall surface and toner receiving port.
    Type: Application
    Filed: May 15, 2014
    Publication date: November 27, 2014
    Applicant: RICOH COMPANY, LTD.
    Inventors: Masashi NAGAYAMA, Hisashi NAKAJIMA, Yoshitaka SEKIGUCHI, Saori YAMADA, Shinya HANATANI, Mariko TAKII, Hiroshi Hosokawa, Shunji KATOH, Shinji TAMAKI, Hiroshi IKEGUCHI, Kenji KIKUCHI, Michiharu SUZUKI
  • Patent number: 8852836
    Abstract: 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: Grant
    Filed: June 18, 2012
    Date of Patent: October 7, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiro Seki, Yoshitaka Sekiguchi, Ryota Inoue, Kazuoki Fuwa
  • Publication number: 20140255840
    Abstract: A toner is provided. The toner includes a crystalline polyester resin (A); and a non-crystalline resin (B). The toner has a viscoelastic property such that the loss tangent (tan ?) defined as a ratio (G?/G?) of loss elastic modulus (G?) to storage elastic modulus (G?) has at least an inflection point or a local maximal point at a temperature ? in a temperature range of from 65° C. to 80° C. while having a local maximal point at a temperature ? in a temperature range of from 75° C. to 90° C., wherein the loss tangent at the temperature ? is from 1.2 to 2.0, and the loss tangent at the temperature ? is from 1.0 to 2.5, wherein the temperature ? is lower than the temperature ?.
    Type: Application
    Filed: January 29, 2014
    Publication date: September 11, 2014
    Inventors: Yoshitaka SEKIGUCHI, Hisashi Nakajima, Masashi Nagayama, Saori Yamada, Shinya Hanatani, Mariko Takii
  • Publication number: 20130260307
    Abstract: A toner including a crystalline polyester resin (A), an amorphous resin (B), and a composite resin (C) having a condensation polymerization resin unit and an addition polymerization resin unit is provided. A molecular weight distribution of the toner based on THF-soluble contents thereof has a main peak within a molecular weight range from 1,000 to 10,000 and a half bandwidth of the main peak is 15,000 or less. The molecular weight distribution is determined by gel permeation chromatography. The toner includes chloroform-insoluble contents. A ratio C/R of the toner is within a range from 0.03 to 0.55. C and R represent heights of spectrum peaks specific to the crystalline polyester resin (A) and the amorphous resin (B), respectively, determined by a Fourier transform infrared spectroscopic attenuation total reflection method after the toner is stored in a thermostatic chamber at 45° C. for 12 hours.
    Type: Application
    Filed: March 14, 2013
    Publication date: October 3, 2013
    Inventors: Masashi Nagayama, Hisashi Nakajima, Saori Yamada, Shinya Hanatani, Mariko Takii, Yoshitaka Sekiguchi