Patents by Inventor Akio TAKEI

Akio TAKEI 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: 11796931
    Abstract: A toner is provided. The toner comprises colored particles and external additives present on surfaces of the colored particles. The colored particles each comprise a core and a shell layer. The core contains a crystalline resin, a non-crystalline resin, and a colorant. The shell layer contains a resin and has a thickness of from 30 to 130 nm. The external additives comprise a metal oxide and a silicon compound. An electronegativity X(A) of the metal oxide and an electronegativity X(Si) of the silicon compound satisfy a relation 0.5?X(A)/X(Si)?0.8. A proportion of an amount of the metal oxide directly adhered to the surfaces of the colored particles to a total amount of the metal oxide present on the colored particles is from 60% to 90% by mass.
    Type: Grant
    Filed: October 1, 2020
    Date of Patent: October 24, 2023
    Assignee: RICOH COMPANY, LTD.
    Inventors: Akio Takei, Takahiro Honda, Tsukiko Takahashi, Tsuneyasu Nagatomo
  • Publication number: 20230305412
    Abstract: A toner includes toner matrix particles containing resin and wax; and an external additive, wherein an average number of voids per toner is 5 or more and 10 or less per toner with a void diameter ? (nm) of voids in the toner matrix particles being 500 ? ? ? 200, as measured based on cross-sectional observation by a scanning electron microscope (SEM).
    Type: Application
    Filed: March 10, 2023
    Publication date: September 28, 2023
    Applicant: Ricoh Company, Ltd
    Inventors: Masahiro YUKIKAWA, Akio Takei, Akinori Saito, Hideto Suzuki
  • Publication number: 20230147363
    Abstract: A toner includes: toner base particles each containing a binder resin; and resin particles on a surface of each of the toner base particles. A glass transition temperature (Tg) of the toner at the first heating in differential scanning calorimetry (DSC) is 20° C. or higher and 50° C. or lower. A glass transition temperature of a tetrahydrofuran (THF)-insoluble component of the toner at the first heating in DSC is ?40° C. or higher and 10° C. or lower. An average circularity of the toner is 0.970 or more and 0.985 or less. A standard deviation of the average circularity is 0.020 or less.
    Type: Application
    Filed: November 8, 2022
    Publication date: May 11, 2023
    Inventors: Ryuuta YOSHIDA, Akio TAKEI, Ryohei YAMAGUCHI, Toma TAKEBAYASHI
  • Publication number: 20230109578
    Abstract: A toner includes toner base particles each containing a binder resin and a release agent, and resin particles on a surface of each of the toner base particles. A ratio (Iw/Ir) is 0.10 or more and 0.30 or less, where Ir is a peak height of the binder resin and Iw is a peak height of the release agent, as measured through attenuated total reflection (ATR). A standard deviation ? (nm) of distances L (nm) between the resin particles that are adjacent to each other on the surface of each of the toner base particles is 150 nm or more and 500 nm or less.
    Type: Application
    Filed: September 29, 2022
    Publication date: April 6, 2023
    Inventors: Kazumasa TABATA, Akio TAKEI, Hiroshi YAMADA, Toma TAKEBAYASHI, Ryuuta YOSHIDA
  • Publication number: 20230014605
    Abstract: A toner includes toner base particles and external additives deposited on a surface of the toner base particle. The toner base particle includes an amorphous polyester resin, a crystalline polyester resin, a release agent, and resin particles. An abundance ratio of the crystalline polyester resin in the surface of the toner base particle as observed by TEM is 2.5% or greater but 25% or less. The resin particles are deposited at the surface of the toner base particle as observed by SEM. A ratio of aggregates of the resin particles occupying the surface of the toner base particle is 1% or greater but 70% or less, where R is a major axis of the minimum particle of the resin particles, and the resin particle having a major axis of 3R or greater is determined as the aggregate.
    Type: Application
    Filed: July 6, 2022
    Publication date: January 19, 2023
    Applicant: Ricoh Company, Ltd.
    Inventors: Akinori SAITOH, Akio Takei, Toma Takebayashi, Masahiro Yukikawa, Tomomi Harashima, 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
  • Patent number: 11340540
    Abstract: Provided is an image forming apparatus including an image bearer, a developing unit configured to develop with a toner, an intermediate transfer member, and a transferring unit, wherein the intermediate transfer member is a laminate including a base layer and an elastic layer including particles at a surface thereof to form convex-concave shapes at the surface, the particles have volume resistivity of from 1×100 ohm*cm through 1×109 ohm*cm, the toner includes additive, an amount of the additive separated from the toner is from 20 percent by mass through 35 percent by mass relative to a total amount of the additive in the toner when a toner dispersion liquid in which the toner is dispersed in a dispersant is irradiated with ultrasonic wave vibration with an irradiation energy dose of 4 kJ, and the toner has a dielectric constant of 2.6 or greater but 3.9 or less.
    Type: Grant
    Filed: December 21, 2018
    Date of Patent: May 24, 2022
    Assignee: Ricoh Company, Ltd.
    Inventors: Akio Takei, Daisuke Inoue, Daichi Hisakuni, Hidetaka Kubo, Masahiro Ohmori, Junichi Awamura
  • 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
  • Publication number: 20210116830
    Abstract: A toner is provided. The toner comprises colored particles and external additives present on surfaces of the colored particles. The colored particles each comprise a core and a shell layer. The core contains a crystalline resin, a non-crystalline resin, and a colorant. The shell layer contains a resin and has a thickness of from 30 to 130 nm. The external additives comprise a metal oxide and a silicon compound. An electronegativity X(A) of the metal oxide and an electronegativity X(Si) of the silicon compound satisfy a relation 0.5?X(A)/X(Si)?0.8. A proportion of an amount of the metal oxide directly adhered to the surfaces of the colored particles to a total amount of the metal oxide present on the colored particles is from 60% to 90% by mass.
    Type: Application
    Filed: October 1, 2020
    Publication date: April 22, 2021
    Inventors: Akio TAKEI, Takahiro HONDA, Tsukiko TAKAHASHI, Tsuneyasu NAGATOMO
  • Publication number: 20210063916
    Abstract: Provided is an image forming apparatus including an image bearer, a developing unit configured to develop with a toner, an intermediate transfer member, and a transferring unit, wherein the intermediate transfer member is a laminate including a base layer and an elastic layer including particles at a surface thereof to form convex-concave shapes at the surface, the particles have volume resistivity of from 1×100 ohm*cm through 1×109 ohm*cm, the toner includes additive, an amount of the additive separated from the toner is from 20 percent by mass through 35 percent by mass relative to a total amount of the additive in the toner when a toner dispersion liquid in which the toner is dispersed in a dispersant is irradiated with ultrasonic wave vibration with an irradiation energy dose of 4 kJ, and the toner has a dielectric constant of 2.6 or greater but 3.9 or less.
    Type: Application
    Filed: December 21, 2018
    Publication date: March 4, 2021
    Inventors: Akio TAKEI, Daisuke INOUE, Daichi HISAKUNI, Hidetaka KUBO, Masahiro OHMORI, Junichi AWAMURA
  • Patent number: 10571834
    Abstract: A fixing method is provided including the step of fixing a toner on a recording medium with a fixing device. The toner has a binder resin, a colorant, and a release agent, and has a release agent amount indicator of from 0.01 to 0.20. The release agent amount indicator is represented by a ratio (P2850/P828) of an intensity (P2850) at a wave number of 2,850 cm?1 to an intensity (P828) at a wave number of 828 cm?1 of the toner measured by a Fourier transform infrared spectroscopy attenuated total reflection method. The fixing device includes a fixing rotator driven to rotate by a driving source, a pressure rotator driven to rotate by rotation of the fixing rotator, a fixing belt interposed between the fixing rotator and the pressure rotator, and a heater to heat the fixing belt.
    Type: Grant
    Filed: February 4, 2019
    Date of Patent: February 25, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryohei Matsuda, Takamasa Hase, Daisuke Inoue, Teppei Kawata, Akio Takei
  • Publication number: 20190243291
    Abstract: A fixing method is provided including the step of fixing a toner on a recording medium with a fixing device. The toner comprises a binder resin, a colorant, and a release agent, and has a release agent amount indicator of from 0.01 to 0.20. The release agent amount indicator is represented by a ratio (P2850/P828) of an intensity (P2850) at a wave number of 2,850 cm?1 to an intensity (P828) at a wave number of 828 cm?1 of the toner measured by a Fourier transform infrared spectroscopy attenuated total reflection method. The fixing device includes a fixing rotator driven to rotate by a driving source, a pressure rotator driven to rotate by rotation of the fixing rotator, a fixing belt interposed between the fixing rotator and the pressure rotator, and a heater to heat the fixing belt.
    Type: Application
    Filed: February 4, 2019
    Publication date: August 8, 2019
    Inventors: Ryohei MATSUDA, Takamasa Hase, Daisuke Inoue, Teppei Kawata, Akio Takei
  • Patent number: 9989869
    Abstract: A toner comprising a binder resin and a release agent, wherein the toner has a difference of 30 or less between a maximum value and a minimum value among peak intensities in a range of Molecular weight M±300 where Molecular weight M is a molecular weight selected from a range of from 300 through 5,000 in a molecular weight distribution of tetrahydrofuran (THF)-soluble components in the toner as measured by gel permeation chromatography (GPC), and wherein the peak intensities are defined as relative values assuming a maximum peak value in molecular weights of 20,000 or less is 100, in a molecular weight distribution curve taking an intensity as a vertical axis and a molecular weight as a horizontal axis as measured by GPC.
    Type: Grant
    Filed: January 5, 2016
    Date of Patent: June 5, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Daisuke Inoue, Naohiro Watanabe, Ryota Inoue, Masana Shiba, Junichi Awamura, Shingo Sakashita, Tomoki Murayama, Yoshitsugu Kimura, Rintaro Takahashi, Akio Takei
  • Publication number: 20180052403
    Abstract: A toner comprising a binder resin and a release agent, wherein the toner has a difference of 30 or less between a maximum value and a minimum value among peak intensities in a range of Molecular weight M±300 where Molecular weight M is a molecular weight selected from a range of from 300 through 5,000 in a molecular weight distribution of tetrahydrofuran (THF)-soluble components in the toner as measured by gel permeation chromatography (GPC), and wherein the peak intensities are defined as relative values assuming a maximum peak value in molecular weights of 20,000 or less is 100, in a molecular weight distribution curve taking an intensity as a vertical axis and a molecular weight as a horizontal axis as measured by GPC.
    Type: Application
    Filed: January 5, 2016
    Publication date: February 22, 2018
    Inventors: Daisuke INOUE, Naohiro WATANABE, Ryota INOUE, Masana SHIBA, Junichi AWAMURA, Shingo SAKASHITA, Tomoki MURAYAMA, Yoshitsugu KIMURA, Rintaro TAKAHASHI, Akio TAKEI