Patents by Inventor Yasuo Kamada

Yasuo Kamada 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: 20230296996
    Abstract: A toner includes toner base and an external additive containing silica. The toner base includes binder resin, colorant, release agent, and modified layered inorganic mineral that is obtained by modifying, with an organic ion, part of ions between layers in layered inorganic mineral. An amount of the modified layered inorganic mineral is 0.1 parts by mass or more and less than 1.4 parts by mass relative to 100 parts by mass of the toner. Liberation ratio A (% by mass) of silica from the toner satisfies relation (1): 0.5?A?1.0. The binder resin includes a component insoluble in THF and a component soluble in THF. The component insoluble in THF has two glass transition temperatures of Tga1st and Tgb1st at first temperature rise in DSC. The Tga1st is ?40° C. or more and 10° C. or less. The Tgb1st is 45° C. or more and 65° C. or less.
    Type: Application
    Filed: March 8, 2023
    Publication date: September 21, 2023
    Applicant: Ricoh Company, Ltd.
    Inventors: Yasuo Kamada, Takafumi Koyama, Tsuyoshi Nozaki, Shun Matsuura
  • Patent number: 11592768
    Abstract: An image forming apparatus includes an image bearer, a developing unit configured to develop a latent image formed on the image bearer with a toner to form a toner image, and a transfer member including a contact area that comes in contact with the image bearer. The toner image is primary transferred from the image bearer to the transfer member. A speed difference between the image bearer and the transfer member at the contact area is 0.1% or greater but 0.8% or less. The toner has an average circularity of 0.971 or greater but 0.986 or less and a shape factor SF-2 of 110 or greater but 119 or less. The speed difference is represented by the following formula: Speed difference [%]={(V1?V2)/V2}×100??[Speed difference] where V1 is a linear speed of the image bearer, and V2 is a linear speed of the transfer member.
    Type: Grant
    Filed: May 13, 2022
    Date of Patent: February 28, 2023
    Assignee: RICOH COMPANY, LTD.
    Inventors: Takahiro Honda, Yasuo Kamada, Hiroshi Yamada
  • Publication number: 20220404743
    Abstract: An image forming apparatus includes an image bearer, a developing unit configured to develop a latent image formed on the image bearer with a toner to form a toner image, and a transfer member including a contact area that comes in contact with the image bearer. The toner image is primary transferred from the image bearer to the transfer member. A speed difference between the image bearer and the transfer member at the contact area is 0.1% or greater but 0.8% or less. The toner has an average circularity of 0.971 or greater but 0.986 or less and a shape factor SF-2 of 110 or greater but 119 or less. The speed difference is represented by the following formula: [Speed Difference] Speed difference[%]={V1?V2)/V2}×100 where V1 is a linear speed of the image bearer, and V2 is a linear speed of the transfer member.
    Type: Application
    Filed: May 13, 2022
    Publication date: December 22, 2022
    Inventors: Takahiro HONDA, Yasuo KAMADA, Hiroshi YAMADA
  • Publication number: 20220291602
    Abstract: Provided is a toner including toner base particles and resin particles. Each toner base particle includes a binder resin, a colorant, and wax. Each resin particle e has a core-shell structure including a core and a shell, where a glass transition temperature TgA of the shell is higher than a glass transition temperature TgB of the core. A surface of each toner base particle is covered with the resin particles. A storage elastic modulus G?1 of the toner at 70° C. during heating is 1.0×105 Pa or greater but 1.0×103 Pa or less, and a storage elastic modulus G?2 of the toner at 100° C. during heating is 1.0×104 Pa or greater but 5.0×104 Pa or less, as the toner is measured by a rheometer.
    Type: Application
    Filed: February 23, 2022
    Publication date: September 15, 2022
    Applicant: Ricoh Company, Ltd.
    Inventors: Yasuo KAMADA, Hiroshi Yamada, Toma Takebayashi, Akio Takei
  • Publication number: 20220137525
    Abstract: The present disclosure provides a toner having excellent low-temperature fixing, heat-resistant-storage property, cleaning performance, and filming resistance. A toner containing toner base particles having a crystalline polyester resin and an amorphous polyester resin includes a plurality of organic particles disposed at least partially embedded in a surface of the toner base particles. A percentage of the crystalline polyester resin occupying the surface of the toner base particles is 4% to 20%, a volume average particle size of the organic particles is 10 nm to 40 nm, and a standard deviation of a distance between adjacent particles of the organic particles that are not in contact is 500 nm or less.
    Type: Application
    Filed: November 2, 2021
    Publication date: May 5, 2022
    Applicant: Ricoh Company, Ltd.
    Inventors: Ryuuta Yoshida, Toma Takebayashi, Akio Takei, Yasuo Kamada
  • Publication number: 20220050395
    Abstract: A toner includes toner particles, each including: a toner base particle including a binder resin, a colorant, and wax; and resin particles on a surface of the toner base particle, wherein Formulae 1 to 3 below are satisfied, where M is a volume average primary particle diameter (nm) of the resin particles, and L is a distance (nm) between the resin particles present next to one another on the surface of the toner base particle: M<L;??(Formula 1) 5 (nm)<M?60 (nm); and??(Formula 2) 0.40?[M (nm)/L (nm)]<0.90.
    Type: Application
    Filed: August 12, 2021
    Publication date: February 17, 2022
    Applicant: Ricoh Company, Ltd.
    Inventors: Hiroshi YAMADA, Akinori Saitoh, Akio Takei, Yasuo Kamada, Toma Takebayashi
  • Publication number: 20210356877
    Abstract: A toner includes toner base particles each including: a binder resin, a colorant, and wax; and resin particles on surfaces of the toner base particles. A standard deviation of a distance between the resin particles next to each other on the surfaces of the toner base particles is less than 500 nm.
    Type: Application
    Filed: May 12, 2021
    Publication date: November 18, 2021
    Inventors: Yasuo KAMADA, Hiroshi YAMADA, Akinori SAITOH, Akio TAKEI, Toma TAKEBAYASHI, Masahiro YUKIKAWA
  • Patent number: 10323134
    Abstract: A particulate polyamide is provided. The particulate polyamide is porous and includes at least one of polyamide 4 and polyamide 3. In addition, the particulate polyamide has a particle diameter (d50) of from 10 ?m to 1,000 ?m and a particle diameter dispersion degree (Dv/Dn) of not greater than 3.0, wherein Dv represents the volume average particle diameter of the particulate polyamide, and Dn represents the number average particle diameter of the particulate polyamide.
    Type: Grant
    Filed: September 17, 2018
    Date of Patent: June 18, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoko Arai, Atsumi Yamabe, Koichiro Oyama, Yasuo Kamada
  • Patent number: 10303072
    Abstract: A toner is provided. The toner contains a polyester resin. The toner has a glass transition temperature (Tg1st) at first temperature rising of differential scanning calorimetry (DSC) of from 45° C. to 65° C. The toner includes a component insoluble in tetrahydrofuran (THF) having two glass transition temperatures (Tga1st and Tgb1st) at the first temperature rising of DSC, where Tga1st is in a range of ?45° C. to 5° C. and Tgb1st is in a range of 45° C. to 70° C. The toner includes a component soluble in THF having a glass transition temperature (Tg2nd) at second temperature rising of DSC of from 40° C. to 65° C.
    Type: Grant
    Filed: February 6, 2018
    Date of Patent: May 28, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Akira Tanaka, Hiroyuki Takeda, Junichi Awamura, Hiroshi Yamada, Daichi Hisakuni, Yasuo Kamada
  • Publication number: 20190016867
    Abstract: A particulate polyamide is provided. The particulate polyamide is porous and includes at least one of polyamide 4 and polyamide 3. In addition, the particulate polyamide has a particle diameter (d50) of from 10 ?m to 1,000 ?m and a particle diameter dispersion degree (Dv/Dn) of not greater than 3.0, wherein Dv represents the volume average particle diameter of the particulate polyamide, and Dn represents the number average particle diameter of the particulate polyamide.
    Type: Application
    Filed: September 17, 2018
    Publication date: January 17, 2019
    Applicant: RICOH COMPANY, LTD.
    Inventors: Yoko ARAI, Atsumi YAMABE, Koichiro OYAMA, Yasuo KAMADA
  • Patent number: 10138344
    Abstract: A particulate polyamide is provided. The particulate polyamide is porous and includes at least one of polyamide 4 and polyamide 3. In addition, the particulate polyamide has a particle diameter (d50) of from 10 ?m to 1,000 ?m and a particle diameter dispersion degree (Dv/Dn) of not greater than 3.0, wherein Dv represents the volume average particle diameter of the particulate polyamide, and Dn represents the number average particle diameter of the particulate polyamide.
    Type: Grant
    Filed: March 18, 2016
    Date of Patent: November 27, 2018
    Assignee: RICOH COMPANY, LTD.
    Inventors: Yoko Arai, Atsumi Yamabe, Koichiro Oyama, Yasuo Kamada
  • Publication number: 20180224763
    Abstract: A toner is provided. The toner contains a polyester resin. The toner has a glass transition temperature (Tg1st) at first temperature rising of differential scanning calorimetry (DSC) of from 45° C. to 65° C. The toner includes a component insoluble in tetrahydrofuran (THF) having two glass transition temperatures (Tga1st and Tgb1st) at the first temperature rising of DSC, where Tga1st is in a range of ?45° C. to 5° C. and Tgb1st is in a range of 45° C. to 70° C. The toner includes a component soluble in THF having a glass transition temperature (Tg2nd) at second temperature rising of DSC of from 40° C. to 65° C.
    Type: Application
    Filed: February 6, 2018
    Publication date: August 9, 2018
    Inventors: Akira TANAKA, Hiroyuki TAKEDA, Junichi AWAMURA, Hiroshi YAMADA, Daichi HISAKUNI, Yasuo KAMADA
  • Patent number: 9587072
    Abstract: To provide a method for producing a polymer, which contains: bringing a ring-opening polymerizable monomer containing an amide bond, and a compressive fluid into contact with each other to melt or dissolve the ring-opening polymerizable monomer containing an amide bond, followed by allowing the ring-opening polymerizable monomer containing an amide bond to react through ring-opening polymerization in the presence of a basic organic metal catalyst and a cocatalyst, to thereby obtain a polymer product.
    Type: Grant
    Filed: May 23, 2014
    Date of Patent: March 7, 2017
    Assignee: Ricoh Company, Ltd.
    Inventors: Taichi Nemoto, Chiaki Tanaka, Yoko Arai, Satoshi Izumi, Yasuo Kamada
  • Publication number: 20160280849
    Abstract: Provided is a polymer product having a branched chain made of polyester, and a weight average molecular weight of 200,000 or greater when measured by gel permeation chromatography.
    Type: Application
    Filed: November 18, 2014
    Publication date: September 29, 2016
    Inventors: Yasuo KAMADA, Taichi NEMOTO, Yoko ARAI, Satoshi IZUMI
  • Publication number: 20160272776
    Abstract: A particulate polyamide is provided. The particulate polyamide is porous and includes at least one of polyamide 4 and polyamide 3. In addition, the particulate polyamide has a particle diameter (d50) of from 10 ?m to 1,000 ?m and a particle diameter dispersion degree (Dv/Dn) of not greater than 3.0, wherein Dv represents the volume average particle diameter of the particulate polyamide, and Dn represents the number average particle diameter of the particulate polyamide.
    Type: Application
    Filed: March 18, 2016
    Publication date: September 22, 2016
    Applicant: RICOH COMPANY, LTD.
    Inventors: Yoko ARAI, Atsumi YAMABE, Koichiro OYAMA, Yasuo KAMADA
  • Patent number: 9447228
    Abstract: A polymer production apparatus, including: supplying unit containing first supplying unit to supply raw materials containing monomer, and second supplying unit to supply compressive fluid; contacting unit to bring the monomer and the compressive fluid into contact together; and outlet configured to discharge reaction product of the monomer, wherein reaction unit is provided between the contacting unit and the outlet, where the reaction unit is to pass the monomer from the contacting unit side to the outlet side, while allowing the monomer to carry out a polymerization reaction in the presence of the compressive fluid, and wherein the reaction unit contains circulation unit containing first pipe and second pipe, where a fluid is passed through the first pipe from the contacting unit side to the outlet side, and the second pipe is to return the fluid from return port provided upstream extrusion unit to inlet provided upstream the return port.
    Type: Grant
    Filed: November 17, 2014
    Date of Patent: September 20, 2016
    Assignee: Ricoh Company, Ltd.
    Inventors: Yuuichi Satoh, Satoshi Izumi, Taichi Nemoto, Yoko Arai, Yasuo Kamada, Chiaki Tanaka
  • Publication number: 20160194445
    Abstract: To provide a method for producing a polymer, which contains: bringing a ring-opening polymerizable monomer containing an amide bond, and a compressive fluid into contact with each other to melt or dissolve the ring-opening polymerizable monomer containing an amide bond, followed by allowing the ring-opening polymerizable monomer containing an amide bond to react through ring-opening polymerization in the presence of a basic organic metal catalyst and a cocatalyst, to thereby obtain a polymer product.
    Type: Application
    Filed: May 23, 2014
    Publication date: July 7, 2016
    Applicant: Ricoh Company, Ltd.
    Inventors: Taichi NEMOTO, Chiaki TANAKA, Yoko ARAI, Satoshi IZUMI, Yasuo KAMADA
  • Publication number: 20160083512
    Abstract: To provide a polymer product, which contains aliphatic polycarbonate, wherein an oxide unit content in the aliphatic polycarbonate is 20 mol % or less, and wherein a monomer content in the aliphatic polycarbonate is 500 ppm or less, where the monomer is a monomer that is a base of the aliphatic polycarbonate.
    Type: Application
    Filed: April 25, 2014
    Publication date: March 24, 2016
    Applicant: RICOH COMPANY, LTD.
    Inventors: Yasuo KAMADA, Taichi NEMOTO, Yoko ARAI, Satoshi IZUMI, Chiaki TANAKA
  • Publication number: 20150361213
    Abstract: Provided is a polymer product, in which the weight average molecular weight measured by gel permeation chromatography is 250,000 or greater and the content of residual ring-opening-polymerizable monomer is 100 ppm by mass or greater but less than 1,000 ppm by mass, or a polymer product, in which the content of residual ring-opening-polymerizable monomer is from 1,000 ppm by mass to 20,000 ppm by mass and the yellow index (YI) value is 15 or less.
    Type: Application
    Filed: January 20, 2014
    Publication date: December 17, 2015
    Inventors: Yasuo KAMADA, Taichi NEMOTO, Satoshi IZUMI, Yoko ARAI, Chiaki TANAKA, Yukihiro IMANAGA
  • Publication number: 20150353677
    Abstract: To provide a polymer production apparatus, which contains: a first supply unit configured to supply raw materials including a monomer; a second supply unit configured to supply a compressive fluid; a contact unit configured to bring the monomer into contact with the compressive fluid; and a reaction unit configured to allow the monomer, which has been brought into contact with the compressive fluid, to react in the presence of the compressive fluid, wherein the reaction unit contains one, or two or more extrusion devices, and one, or two or more stirring devices.
    Type: Application
    Filed: January 27, 2014
    Publication date: December 10, 2015
    Applicant: Ricoh Company, Ltd.
    Inventors: Satoshi IZUMI, Taichi NEMOTO, Yoko ARAI, Yasuo KAMADA, Chiaki TANAKA