Patents by Inventor Shuichi Hiroko

Shuichi Hiroko 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: 9971264
    Abstract: The magnetic toner contains a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein the average circularity of the magnetic toner is at least 0.955 and, when classifying the inorganic fine particles, in accordance with the fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X are in prescribed ranges.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: May 15, 2018
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tomohisa Sano, Yusuke Hasegawa, Shuichi Hiroko, Yoshitaka Suzumura, Keisuke Tanaka
  • Patent number: 9971262
    Abstract: A magnetic toner containing a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein when the inorganic fine particles are classified as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles in accordance with fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X of coverage of the magnetic toner surface by the third inorganic fine particles are in prescribed ranges.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: May 15, 2018
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yusuke Hasegawa, Tomohisa Sano, Shuichi Hiroko, Yoshitaka Suzumura, Keisuke Tanaka
  • Patent number: 9625842
    Abstract: A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the re
    Type: Grant
    Filed: July 22, 2016
    Date of Patent: April 18, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kozue Uratani, Michihisa Magome, Yusuke Hasegawa, Shuichi Hiroko
  • Patent number: 9625841
    Abstract: A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.
    Type: Grant
    Filed: July 22, 2016
    Date of Patent: April 18, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Shuichi Hiroko, Michihisa Magome, Yusuke Hasegawa, Yoshitaka Suzumura
  • Patent number: 9551947
    Abstract: A magnetic toner is provided that exhibits an excellent dot reproducibility and developing performance after being allowed to stand in a high temperature and high humidity environment and an excellent low-temperature fixability. The magnetic toner has an inorganic fine powder and a magnetic toner particle containing a binder resin, a magnetic body, and a release agent, wherein in a stress relaxation measurement using a rotating plate rheometer, the magnetic toner exhibits a yield value A at 25° C. of at least 3×106 (sec), and the magnetic toner that has been heated to 80° C. and then cooled to 25° C. exhibits a yield value B at 25° C. of not more than 1×105 (sec).
    Type: Grant
    Filed: August 8, 2011
    Date of Patent: January 24, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Shuichi Hiroko, Yoshihiro Nakagawa, Tomohisa Sano
  • Publication number: 20160334723
    Abstract: A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the re
    Type: Application
    Filed: July 22, 2016
    Publication date: November 17, 2016
    Inventors: Kozue Uratani, Michihisa Magome, Yusuke Hasegawa, Shuichi Hiroko
  • Publication number: 20160327881
    Abstract: A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.
    Type: Application
    Filed: July 22, 2016
    Publication date: November 10, 2016
    Inventors: Shuichi Hiroko, Michihisa Magome, Yusuke Hasegawa, Yoshitaka Suzumura
  • Patent number: 9423711
    Abstract: A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the re
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: August 23, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Kozue Uratani, Michihisa Magome, Yusuke Hasegawa, Shuichi Hiroko
  • Patent number: 9417542
    Abstract: A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.
    Type: Grant
    Filed: December 26, 2012
    Date of Patent: August 16, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Shuichi Hiroko, Michihisa Magome, Yusuke Hasegawa, Yoshitaka Suzumura
  • Patent number: 9372424
    Abstract: A magnetic toner contains magnetic toner particles and silica fine particles. The magnetic toner has a thermal conductivity in the range of 0.230 to 0.270 W/(m·K). Primary particles of the silica fine particles have a number-average particle diameter (D1) in the range of 5 to 20 nm. The coverage X1 of the magnetic toner surface by the silica fine particles ranges from 40% to 75% by area as determined using an X-ray photoelectron spectrometer (ESCA). The diffusion index (X1/X2) satisfies the following formula: Diffusion index??0.0042×X1+0.62 wherein X2 denotes the theoretical coverage of the magnetic toner surface by the silica fine particles.
    Type: Grant
    Filed: December 11, 2014
    Date of Patent: June 21, 2016
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Matsui, Yusuke Hasegawa, Shuichi Hiroko, Yoshitaka Suzumura, Atsuhiko Ohmori, Keisuke Tanaka
  • Patent number: 9239528
    Abstract: A toner comprising toner particles which comprise a binder resin and a colorant, and also inorganic fine particles as external additives, wherein the inorganic fine particles are silica fine particles and a group 2 element titanate fine particles, the inorganic fine particles have specific particle diameters, the silica fine particles have a coverage ratio X1 on the surfaces of the toner particles, which is not less than 40.0 surface area % and not more than 75.0 surface area %, when the theoretical coverage ratio by the silica fine particles is X2, the diffusion index defined as “diffusion index=X1/X2” satisfies the condition: diffusion index??0.0042×X1+0.62, and the external additives have an embedding ratio on the toner particles, which satisfies a specific range.
    Type: Grant
    Filed: June 13, 2014
    Date of Patent: January 19, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yusuke Hasegawa, Takashi Matsui, Shuichi Hiroko, Yoshitaka Suzumura, Atsuhiko Ohmori, Keisuke Tanaka
  • Patent number: 9213250
    Abstract: Disclosed is a toner which enables a stable image density to be obtained, regardless of the service environment, throughout use in durability tests, and which is able to suppress the occurrence of faulty cleaning. The toner contains both toner particles, which include a binder resin and a colorant, and also silica fine particles. The toner has an average circularity of at least 0.950, a static friction coefficient, with respect to a polycarbonate resin substrate, of at least 0.100 and not more than 0.200, and a coverage ratio X1 of the toner surface by the silica fine particles, as determined by X-ray photoelectron spectroscopy (ESCA), of at least 50.0 area %, and not more than 75.0 area %.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: December 15, 2015
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Shotaro Nomura, Yusuke Hasegawa, Takashi Matsui, Shuichi Hiroko, Yoshitaka Suzumura, Atsuhiko Ohmori
  • Publication number: 20150227067
    Abstract: A magnetic toner containing a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein when the inorganic fine particles are classified as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles in accordance with fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X of coverage of the magnetic toner surface by the third inorganic fine particles are in prescribed ranges.
    Type: Application
    Filed: April 23, 2015
    Publication date: August 13, 2015
    Inventors: Yusuke Hasegawa, Tomohisa Sano, Shuichi Hiroko, Yoshitaka Suzumura, Keisuke Tanaka
  • Publication number: 20150227068
    Abstract: The magnetic toner contains a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein the average circularity of the magnetic toner is at least 0.955 and, when classifying the inorganic fine particles, in accordance with the fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X are in prescribed ranges.
    Type: Application
    Filed: April 23, 2015
    Publication date: August 13, 2015
    Inventors: Tomohisa Sano, Yusuke Hasegawa, Shuichi Hiroko, Yoshitaka Suzumura, Keisuke Tanaka
  • Publication number: 20150168859
    Abstract: A magnetic toner contains magnetic toner particles and silica fine particles. The magnetic toner has a thermal conductivity in the range of 0.230 to 0.270 W/(m·K). Primary particles of the silica fine particles have a number-average particle diameter (D1) in the range of 5 to 20 nm. The coverage X1 of the magnetic toner surface by the silica fine particles ranges from 40% to 75% by area as determined using an X-ray photoelectron spectrometer (ESCA). The diffusion index (X1/X2) satisfies the following formula: Diffusion index??0.0042×X1+0.62 wherein X2 denotes the theoretical coverage of the magnetic toner surface by the silica fine particles.
    Type: Application
    Filed: December 11, 2014
    Publication date: June 18, 2015
    Inventors: Takashi Matsui, Yusuke Hasegawa, Shuichi Hiroko, Yoshitaka Suzumura, Atsuhiko Ohmori, Keisuke Tanaka
  • Publication number: 20140377696
    Abstract: A toner comprising toner particles which comprise a binder resin and a colorant, and also inorganic fine particles as external additives, wherein the inorganic fine particles are silica fine particles and a group 2 element titanate fine particles, the inorganic fine particles have specific particle diameters, the silica fine particles have a coverage ratio X1 on the surfaces of the toner particles, which is not less than 40.0 surface area % and not more than 75.0 surface area %, when the theoretical coverage ratio by the silica fine particles is X2, the diffusion index defined as “diffusion index=X1/X2” satisfies the condition: diffusion index??0.0042×X1+0.62, and the external additives have an embedding ratio on the toner particles, which satisfies a specific range.
    Type: Application
    Filed: June 13, 2014
    Publication date: December 25, 2014
    Inventors: Yusuke Hasegawa, Takashi Matsui, Shuichi Hiroko, Yoshitaka Suzumura, Atsuhiko Ohmori, Keisuke Tanaka
  • Publication number: 20140370431
    Abstract: A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.
    Type: Application
    Filed: December 26, 2012
    Publication date: December 18, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Shuichi Hiroko, Michihisa Magome, Yusuke Hasegawa, Yoshitaka Suzumura
  • Publication number: 20140335449
    Abstract: A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the re
    Type: Application
    Filed: January 31, 2013
    Publication date: November 13, 2014
    Inventors: Kozue Uratani, Michihisa Magome, Yusuke Hasegawa, Shuichi Hiroko
  • Patent number: 8841054
    Abstract: An image-forming method is provided which can provide stable image density irrespective of use environments and does not cause image defects such as fogging, tailing, or transfer voids, even when being applied to a developing sleeve with a reduced diameter. In the image-forming method, a latent image bearing member and a toner bearing member bearing a magnetic toner on its surface and having inside a unit for generating a magnetic field are placed with a predetermined interval, and an alternating field is applied between the latent image bearing member and the toner bearing member, and an electrostatic latent image borne by the latent image bearing member is developed with the magnetic toner. The toner bearing member has a specific diameter, and the magnetic toner has a specific circularity and a specific compressibility. The total energy of the toner measured with a powder flowability measuring apparatus satisfies a specific value.
    Type: Grant
    Filed: October 20, 2008
    Date of Patent: September 23, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tadashi Dojo, Michihisa Magome, Eriko Yanase, Takashi Matsui, Tomohisa Sano, Akira Sakakibara, Shuichi Hiroko
  • Patent number: 8778585
    Abstract: A toner with good low-temperature fixability even in light-pressure type fixing units, which causes no contamination of fixing films and provides images having stable image densities and excellent image quality after long-term use. The toner includes a toner particle containing a binder resin, a coloring agent, a release agents (a) and (b) The release agent (a) is a monofunctional or bifunctional ester wax; the release agent (b) is a hydrocarbon wax; a solubility of the release agent (a) into the binder resin is higher than that of the release agent (b). When tetrahydrofuran-soluble components of the toner are subjected to GPC, a proportion of components having a molecular weight of 500 or less is 2.5 area % or less. When the tetrahydrofuran-soluble components at 25° C. are subjected to SEC-MALLS, a weight-average molecular weight Mw thereof is 5,000-100,000, and the Mw and the radius of gyration Rw thereof satisfy 5.0×10?4?Rw/Mw?1.0×10?2.
    Type: Grant
    Filed: September 12, 2011
    Date of Patent: July 15, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Matsui, Michihisa Magome, Tomohisa Sano, Shuichi Hiroko, Yoshitaka Suzumura, Shotaro Nomura