Patents by Inventor Mayumi Yoshihara

Mayumi Yoshihara 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: 20240117206
    Abstract: An ink contains water, a coloring material, a resin, and an organic solvent, wherein the dried layer of the ink has a surface free energy ?S having a polar component ?Sp of from 3.5 to 20 J/m2 at 25 degrees C.
    Type: Application
    Filed: September 22, 2023
    Publication date: April 11, 2024
    Applicant: Ricoh Company, Ltd.
    Inventors: Mayumi YOSHIHARA, Michihiko Namba, Takashi Tamai, Shin Hasegawa, Yuta Nakamura, Daiki Hasebe
  • Publication number: 20230183501
    Abstract: An ink contains water, a coloring material, a resin, two or more types of organic solvents, and a surfactant, wherein the ink is horizontally discharged to a substrate.
    Type: Application
    Filed: October 27, 2022
    Publication date: June 15, 2023
    Inventors: Shin HASEGAWA, Takashi TAMAI, Michihiko NAMBA, Yuta NAKAMURA, Mayumi YOSHIHARA, Daiki HASEBE
  • Publication number: 20220363927
    Abstract: A clear ink includes resin particles, water, and a compound represented by General Formula (1) below. The resin particles have a volume average particle diameter of 50 nm or less. A dried film of the clear ink has glass transition temperatures (Tg) at 50 degrees Celsius or higher and at lower than 0 degrees Celsius. In the General Formula (1), R1 represents an alkyl group having 1 or more but 4 or less carbon atoms.
    Type: Application
    Filed: April 8, 2022
    Publication date: November 17, 2022
    Inventors: Hiroaki TAKAHASHI, Kiminori MASUDA, Mayumi YOSHIHARA
  • Publication number: 20220363063
    Abstract: A discharge apparatus includes an ink accommodating unit that accommodates a clear ink, a discharge head including a nozzle configured to discharge the clear ink to a print target, a heating unit configured to heat the print target, and a wiping member configured to wipe a nozzle-formed surface of the discharge head including the nozzle. The clear ink includes water and resin particles having a volume average particle diameter of 50 nm or less. A dried film of the clear ink has glass transition temperatures (Tg) at 50 degrees Celsius or higher and at lower than 0 degrees Celsius.
    Type: Application
    Filed: May 4, 2022
    Publication date: November 17, 2022
    Inventors: Kiminori MASUDA, Hiroaki TAKAHASHI, Mayumi YOSHIHARA
  • Patent number: 11274221
    Abstract: An ink includes at least one polyether-modified siloxane compound, and at least one aliphatic alcohol alkylene oxide compound. The mass ratio of the polyether-modified siloxane compound to the aliphatic alcohol alkylene oxide compound in the ink is from 95/5 to 50/50.
    Type: Grant
    Filed: October 24, 2018
    Date of Patent: March 15, 2022
    Assignee: RICOH COMPANY, LTD.
    Inventors: Kazuhiko Umemura, Yuuki Yokohama, Akihiko Matsuyama, Amika Sagara, Masaki Kudo, Mayumi Yoshihara, Kento Sugita
  • Patent number: 11059983
    Abstract: An ink comprises a pigment, a quinacridone derivative represented by the following Chemical formula 1. where R1, R2, R3, and R4 each, independently represent hydrogen atoms, halogen atoms, or alkyl groups having 1 to 4 carbon atoms. R5 and R6 each, independently represent alkyl groups having 1 to 4 carbon atoms, and m and n each, independently represent 0, 1, or 2, excluding a case where both m and n are simultaneously 0, and a solvent A having an SP value of from 9.0 to 11.0, wherein the proportion of the solvent A in the ink is less than 10 percent by mass.
    Type: Grant
    Filed: February 5, 2019
    Date of Patent: July 13, 2021
    Assignee: Ricoh Company, Ltd.
    Inventors: Akihiko Matsuyama, Yuuki Yokohama, Amika Sagara, Masaki Kudo, Kazuhiko Umemura, Yukihiro Imanaga, Mayumi Yoshihara
  • Publication number: 20190249020
    Abstract: An ink comprises a pigment, a quinacridone derivative represented by the following Chemical formula 1. where R1, R2, R3, and R4 each, independently represent hydrogen atoms, halogen atoms, or alkyl groups having 1 to 4 carbon atoms. R5 and R6 each, independently represent alkyl groups having 1 to 4 carbon atoms, and m and n each, independently represent 0, 1, or 2, excluding a case where both m and n are simultaneously 0, and a solvent A having an SP value of from 9.0 to 11.0, wherein the proportion of the solvent A in the ink is less than 10 percent by mass.
    Type: Application
    Filed: February 5, 2019
    Publication date: August 15, 2019
    Inventors: Akihiko MATSUYAMA, Yuuki Yokohama, Amika Sagara, Masaki Kudo, Kazuhiko Umemura, Yukihiro Imanaga, Mayumi Yoshihara
  • Publication number: 20190185690
    Abstract: An ink includes at least one polyether-modified siloxane compound, and at least one aliphatic alcohol alkylene oxide compound. The mass ratio of the polyether-modified siloxane compound to the aliphatic alcohol alkylene oxide compound in the ink is from 95/5 to 50/50.
    Type: Application
    Filed: October 24, 2018
    Publication date: June 20, 2019
    Inventors: Kazuhiko UMEMURA, Yuuki YOKOHAMA, Akihiko MATSUYAMA, Amika SAGARA, Masaki KUDO, Mayumi YOSHIHARA, Kento SUGITA
  • Patent number: 9864322
    Abstract: An image forming apparatus includes an image bearer; a charging member to charge the surface of the image bearer; an irradiating member to irradiate the surface of the image bearer to form an electrostatic latent image on the surface of the image bearer; an developing member to develop the electrostatic latent image with a toner to form a visible toner image on the surface of the image bearer; and a transferring member to transfer the toner image onto a transfer material. The image bearer includes a charge generation layer including an asymmetrical disazo pigment and a metal-free phthalocyanine pigment, and a charge transport layer. The irradiating member forms the electrostatic latent image at an irradiation energy greater than a half decay exposure of the image bearer and not greater than 2.5 times of the half decay exposure. The image bearer is not discharged every image forming process.
    Type: Grant
    Filed: May 20, 2016
    Date of Patent: January 9, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Mayumi Yoshihara, Koichi Kato
  • Publication number: 20160363886
    Abstract: An image forming apparatus includes an image bearer; a charging member to charge the surface of the image bearer; an irradiating member to irradiate the surface of the image bearer to form an electrostatic latent image on the surface of the image bearer; an developing member to develop the electrostatic latent image with a toner to form a visible toner image on the surface of the image bearer; and a transferring member to transfer the toner image onto a transfer material. The image bearer includes a charge generation layer including an asymmetrical disazo pigment and a metal-free phthalocyanine pigment, and a charge transport layer. The irradiating member forms the electrostatic latent image at an irradiation energy greater than a half decay exposure of the image bearer and not greater than 2.5 times of the half decay exposure. The image bearer is not discharged every image forming process.
    Type: Application
    Filed: May 20, 2016
    Publication date: December 15, 2016
    Inventors: Mayumi YOSHIHARA, Koichi KATO
  • Publication number: 20160313676
    Abstract: A surface processor processing the surface of a recording medium before a toner image is formed thereon includes a surface reformer to reform the surface of the recording medium a toner image is formed on; and an applicator to apply the surface of the recording medium after reformed with a toner affinity ingredient.
    Type: Application
    Filed: July 6, 2016
    Publication date: October 27, 2016
    Inventors: Masahide YAMASHITA, Koichi KATO, Mayumi YOSHIHARA, Sayaka KATOH
  • Publication number: 20160033920
    Abstract: A surface processor processing the surface of a recording medium before a toner image is formed thereon includes a surface reformer to reform the surface of the recording medium a toner image is formed on; and an applicator to apply the surface of the recording medium after reformed with a toner affinity ingredient.
    Type: Application
    Filed: July 13, 2015
    Publication date: February 4, 2016
    Inventors: Masahide YAMASHITA, Koichi KATO, Mayumi YOSHIHARA, Sayaka KATOH
  • Patent number: 9201334
    Abstract: An image forming apparatus includes an electrophotographic photoreceptor that bears a latent image, an electrostatic charging unit that negatively charges the electrophotographic photoreceptor uniformly with electricity, and a latent image writing unit that writes a latent image on the electrophotographic photoreceptor. A one-component developing unit renders the latent image visible by developing thereof. A transfer device transfers the toner image from the electrophotographic photoreceptor onto a transfer medium. The inequality C×V<Q?1.
    Type: Grant
    Filed: August 27, 2014
    Date of Patent: December 1, 2015
    Assignee: RICOH COMPANY, LTD.
    Inventors: Masahide Yamashita, Mayumi Yoshihara
  • Publication number: 20150071662
    Abstract: An image forming apparatus includes an electrophotographic photoreceptor that bears a latent image, an electrostatic charging unit that negatively charges the electrophotographic photoreceptor uniformly with electricity, and a latent image writing unit that writes a latent image on the electrophotographic photoreceptor. A one-component developing unit renders the latent image visible by developing thereof. A transfer device transfers the toner image from the electrophotographic photoreceptor onto a transfer medium. The inequality C×V<Q?1.
    Type: Application
    Filed: August 27, 2014
    Publication date: March 12, 2015
    Applicant: Ricoh Company, Ltd.
    Inventors: Masahide YAMASHITA, Mayumi YOSHIHARA
  • Patent number: 8351823
    Abstract: An image forming apparatus including an image bearing member having a photosensitive layer and the surface including concave portions having a concave diameter of from 5 to 200 ?m, an irradiation device that irradiates the surface of the image bearing member with light to form a latent electrostatic image thereon, a development device that develops the latent electrostatic image with a development agent containing toner to obtain a visualized image, a transfer device that transfers the visualized image to a transfer medium, a first cleaning brush to which a bias is applied with a polarity reverse to that of the toner remaining on the surface of the image bearing member after the visualized image is transferred, and a second cleaning brush to which a bias is applied with the same polarity as that of the toner remaining on the surface of the image bearing member.
    Type: Grant
    Filed: June 29, 2010
    Date of Patent: January 8, 2013
    Assignee: Ricoh Company, Ltd
    Inventors: Shinji Nohsho, Mayumi Yoshihara, Mihoko Matsumoto, Yukio Fujiwara, Kohsuke Yamamoto
  • Patent number: 8293439
    Abstract: An electrophotographic photoreceptor including a conductive substrate, a photosensitive layer, and a surface layer, which satisfies the following inequations: 0.005<WRa(LMH)<0.03??(i) 0.010<WRa(LHH)<0.03??(ii) 0.005<WRa(LML)<0.20??(iii) WRa(LLH)>WRa(LMH)??(iv) WRa(LLH)>WRa(LHH)??(v) wherein WRa (?m) represents a center-line average roughness of frequency components LHH, LHL, LMH, LML, LLH, and LLL that are obtained by subjecting a one-dimensional data array of a surface profile of the electrophotographic photoreceptor to wavelet transformation multiresolution analysis so as to be separated into 6 frequency components; thinning a one-dimensional data array of the lowest frequency component so that the number of data array is reduced to 1/40; and subjecting the thinned one-dimensional data array to wavelet transformation multiresolution analysis so as to be separated into the 6 frequency components LHH, LHL, LMH, LML, LLH, and LLL.
    Type: Grant
    Filed: March 12, 2010
    Date of Patent: October 23, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Yukio Fujiwara, Hidetoshi Kami, Kazuhiro Egawa, Shinji Nohsho, Mayumi Yoshihara, Mihoko Matsumoto, Kohsuke Yamamoto
  • Publication number: 20100329741
    Abstract: An image forming apparatus including an image bearing member having a photosensitive layer and the surface including concave portions having a concave diameter of from 5 to 200 ?m, an irradiation device that irradiates the surface of the image bearing member with light to form a latent electrostatic image thereon, a development device that develops the latent electrostatic image with a development agent containing toner to obtain a visualized image, a transfer device that transfers the visualized image to a transfer medium, a first cleaning brush to which a bias is applied with a polarity reverse to that of the toner remaining on the surface of the image bearing member after the visualized image is transferred, and a second cleaning brush to which a bias is applied with the same polarity as that of the toner remaining on the surface of the image bearing member.
    Type: Application
    Filed: June 29, 2010
    Publication date: December 30, 2010
    Inventors: Shinji NOHSHO, Mayumi Yoshihara, Mihoko Matsumoto, Yukio Fujiwara, Kohsuke Yamamoto
  • Publication number: 20100232831
    Abstract: An electrophotographic photoreceptor including a conductive substrate, a photosensitive layer, and a surface layer, which satisfies the following inequations: 0.005<WRa(LMH)<0.03??(i) 0.010<WRa(LHH)<0.03??(ii) 0.005<WRa(LML)<0.20??(iii) WRa(LLH)>WRa(LMH)??(iv) WRa(LLH)>WRa(LHH)??(v) wherein WRa (?m) represents a center-line average roughness of frequency components LHH, LHL, LMH, LML, LLH, and LLL that are obtained by subjecting a one-dimensional data array of a surface profile of the electrophotographic photoreceptor to wavelet transformation multiresolution analysis so as to be separated into 6 frequency components; thinning a one-dimensional data array of the lowest frequency component so that the number of data array is reduced to 1/40; and subjecting the thinned one-dimensional data array to wavelet transformation multiresolution analysis so as to be separated into the 6 frequency components LHH, LHL, LMH, LML, LLH, and LLL.
    Type: Application
    Filed: March 12, 2010
    Publication date: September 16, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Yukio Fujiwara, Hidetoshi Kami, Kazuhiro Egawa, Shinji Nohsho, Mayumi Yoshihara, Mihoko Matsumoto, Kohsuke Yamamoto