Patents by Inventor Takuto KUROKAWA

Takuto KUROKAWA 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: 11462242
    Abstract: Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is 0.04 ?m to 0.08 ?m, and an absolute value ?N of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.
    Type: Grant
    Filed: May 21, 2021
    Date of Patent: October 4, 2022
    Assignee: FUJIFILM Corporation
    Inventors: Takahiro Iwamoto, Hidemasa Hosoda, Norihito Kasada, Takuto Kurokawa
  • Publication number: 20220270644
    Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A rate of change (AlFeSil abrasion value 2/AlFeSil abrasion value 1) in AlFeSil abrasion value measured on a surface of the magnetic layer before and after storage of the magnetic tape in an environment of a temperature of 23° C. and a relative humidity of 50% is 0.7 or more.
    Type: Application
    Filed: February 16, 2022
    Publication date: August 25, 2022
    Applicant: FUJIFILM Corporation
    Inventors: Takuto KUROKAWA, Norihito KASADA, So MATSUYAMA
  • Publication number: 20220254373
    Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A rate of change in friction coefficient on an LTO8 head measured on a surface of the magnetic layer before and after storage of the magnetic tape is 0.7 or more.
    Type: Application
    Filed: February 8, 2022
    Publication date: August 11, 2022
    Applicant: FUJIFILM Corporation
    Inventors: Takuto Kurokawa, So Matsuyama, Norihito Kasada
  • Patent number: 11373680
    Abstract: Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is 0.04 ?m to 0.08 ?m, and an absolute value ?N of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.
    Type: Grant
    Filed: March 27, 2020
    Date of Patent: June 28, 2022
    Assignee: FUJIFILM Corporation
    Inventors: Takahiro Iwamoto, Hidemasa Hosoda, Norihito Kasada, Takuto Kurokawa
  • Patent number: 11367460
    Abstract: The magnetic recording medium including: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer is 1.0 nm to 1.6 nm, and a difference (Safter?Sbefore) between a spacing Safter measured by optical interferometry regarding the surface of the magnetic layer after methyl ethyl ketone cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the magnetic layer before methyl ethyl ketone cleaning is greater than 0 nm and equal to or smaller than 15.0 nm.
    Type: Grant
    Filed: March 28, 2019
    Date of Patent: June 21, 2022
    Assignee: FUJIFILM Corporation
    Inventors: Eiki Ozawa, Takuto Kurokawa
  • Patent number: 11348604
    Abstract: The magnetic recording and reproducing device includes a magnetic recording medium, a recording element, and a reproducing element. The recording element is an inductive recording element having a first magnetic pole which generates a magnetic field, and a second magnetic pole which is spaced apart from the first magnetic pole with a write gap interposed therebetween, a tip width of the first magnetic pole is substantially the same as a tip width of the second magnetic pole, and a reproducing element width of the reproducing element is 0.5 ?m to 0.8 ?m. The magnetic recording medium has a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, and the number of recesses, which are present in a surface of the magnetic layer and have an equivalent circle diameter of 0.20 ?m to 0.50 ?m, is 10 to 500 per area of 40 ?m×40 ?m.
    Type: Grant
    Filed: June 4, 2021
    Date of Patent: May 31, 2022
    Assignee: FUJIFILM Corporation
    Inventors: So Matsuyama, Norihito Kasada, Takuto Kurokawa
  • Patent number: 11302357
    Abstract: The magnetic recording medium includes: a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which a difference between a spacing measured on a surface of the back coating layer by optical interferometry under a pressure of 0.5 atm after n-hexane cleaning and a spacing measured on the surface of the back coating layer by optical interferometry under a pressure of 13.5 atm after n-hexane cleaning is 12 nm or more.
    Type: Grant
    Filed: September 18, 2020
    Date of Patent: April 12, 2022
    Assignee: FUJIFILM Corporation
    Inventors: Naoki Sano, Takuto Kurokawa, Eiki Ozawa, Norihito Kasada, Megumi Nakano
  • Patent number: 11270725
    Abstract: The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder, in which a difference (S0.5?S13.5) between a spacing S0.5 measured on a surface of the magnetic layer by optical interferometry after n-hexane cleaning under a pressure of 0.5 atm and a spacing S13.5 measured on the surface of the magnetic layer by optical interferometry after n-hexane cleaning under a pressure of 13.5 atm is 9.0 nm or more.
    Type: Grant
    Filed: February 27, 2020
    Date of Patent: March 8, 2022
    Assignee: FUJIFILM Corporation
    Inventors: Naoki Sano, Eiki Ozawa, Norihito Kasada, Takuto Kurokawa
  • Patent number: 11270728
    Abstract: The magnetic recording medium includes a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which a difference between a spacing measured on a surface of the back coating layer by optical interferometry under a pressure of 0.5 atm after n-hexane cleaning and a spacing measured on the surface of the back coating layer by optical interferometry under a pressure of 13.5 atm after n-hexane cleaning is 3 nm or less.
    Type: Grant
    Filed: September 16, 2020
    Date of Patent: March 8, 2022
    Assignee: FUJIFILM Corporation
    Inventors: Takuto Kurokawa, Naoki Sano, Norihito Kasada, Eiki Ozawa, Megumi Nakano
  • Publication number: 20220020392
    Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer including a ferromagnetic powder, in which in an environment of a temperature of 32° C. and a relative humidity of 80%, a frictional force F0.2 N on a magnetic layer surface with respect to an LTO8 head, which is measured by applying a tension of 0.2 N in a longitudinal direction of the magnetic tape, is in a range of 4 to 15 gf, and a frictional force F1.5 N on the magnetic layer surface with respect to the LTO8 head, which is measured by applying a tension of 1.5 N in the longitudinal direction of the magnetic tape, is in a range of 4 to 15 gf.
    Type: Application
    Filed: July 15, 2021
    Publication date: January 20, 2022
    Applicant: FUJIFILM Corporation
    Inventors: Takuto KUROKAWA, So MATSUYAMA, Norihito KASADA
  • Publication number: 20220020393
    Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer including a ferromagnetic powder, in which in an environment of a temperature of 23° C. and a relative humidity of 50%, an AlFeSil abrasion value0.2 N on a magnetic layer surface, which is measured by applying a tension of 0.2 N in a longitudinal direction of the magnetic tape, is in a range of 20 to 50 ?m, and an AlFeSil abrasion value1.5 N on the magnetic layer surface measured by applying a tension of 1.5 N in the longitudinal direction of the magnetic tape is in a range of 20 to 50 ?m.
    Type: Application
    Filed: July 15, 2021
    Publication date: January 20, 2022
    Applicant: FUJIFILM Corporation
    Inventors: Takuto KUROKAWA, So MATSUYAMA, Norihito KASADA
  • Patent number: 11211087
    Abstract: The magnetic tape includes a non-magnetic support; a magnetic layer including a ferromagnetic powder and a binding agent on one surface of the non-magnetic support; and a back coating layer including a non-magnetic powder and a binding agent on the other surface of the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the back coating layer is equal to or smaller than 7.0 nm, and a difference between a spacing Safter measured by optical interferometry regarding the surface of the back coating layer after methyl ethyl ketone cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the back coating layer before methyl ethyl ketone cleaning is greater than 0 nm and equal to or smaller than 30.0 nm.
    Type: Grant
    Filed: March 28, 2019
    Date of Patent: December 28, 2021
    Assignee: FUJIFILM Corporation
    Inventors: Eiki Ozawa, Takuto Kurokawa
  • Publication number: 20210398555
    Abstract: The magnetic recording and reproducing device includes a magnetic recording medium, a recording element, and a reproducing element. The recording element is an inductive recording element having a first magnetic pole which generates a magnetic field, and a second magnetic pole which is spaced apart from the first magnetic pole with a write gap interposed therebetween, a tip width of the first magnetic pole is substantially the same as a tip width of the second magnetic pole, and a reproducing element width of the reproducing element is 0.5 ?m to 0.8 ?m. The magnetic recording medium has a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, and the number of recesses, which are present in a surface of the magnetic layer and have an equivalent circle diameter of 0.20 ?m to 0.50 ?m, is 10 to 500 per area of 40 ?m×40 ?m.
    Type: Application
    Filed: June 4, 2021
    Publication date: December 23, 2021
    Applicant: FUJIFILM Corporation
    Inventors: So MATSUYAMA, Norihito KASADA, Takuto KUROKAWA
  • Publication number: 20210383827
    Abstract: The magnetic recording and reproducing device includes a magnetic recording medium, a recording element, and a reproducing element. The recording element is an inductive recording element having a first magnetic pole which generates a magnetic field, and a second magnetic pole which is spaced apart from the first magnetic pole with a write gap interposed therebetween, a tip width of the first magnetic pole is substantially the same as a tip width of the second magnetic pole, and a reproducing element width of the reproducing element is 0.2 ?m or greater and less than 0.5 ?m. In the magnetic recording medium, the number of recesses, which are present in a surface of the magnetic layer and have an equivalent circle diameter of 0.10 ?m or greater and less than 0.20 ?m, is 100 to 2,000 per area of 40 ?m×40 ?m.
    Type: Application
    Filed: June 4, 2021
    Publication date: December 9, 2021
    Applicant: FUJIFILM Corporation
    Inventors: So MATSUYAMA, Norihito KASADA, Takuto KUROKAWA
  • Publication number: 20210287712
    Abstract: Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is 0.04 ?m to 0.08 ?m, and an absolute value ?N of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.
    Type: Application
    Filed: May 21, 2021
    Publication date: September 16, 2021
    Applicant: FUJIFILM Corporation
    Inventors: Takahiro IWAMOTO, Hidemasa Hosoda, Norihito Kasada, Takuto Kurokawa
  • Publication number: 20210241792
    Abstract: The magnetic tape in which a difference (S0.1?S1.6) between a spacing S0.1 and a spacing S1.6 obtained after n-hexane cleaning on a surface of the magnetic layer is equal to or less than 32 nm. The S0.1 is a value obtained as a spacing under a pressing force of 0.1 atm from a relational expression between a pressure and a spacing obtained by performing a spacing measurement on the surface of the magnetic layer by an optical interference method under a pressing force of each of a plurality of different pressures after the n-hexane cleaning, and S1.6 is a spacing measured on the surface of the magnetic layer by the optical interference method under the pressing force of 1.6 atm after the n-hexane cleaning.
    Type: Application
    Filed: January 28, 2021
    Publication date: August 5, 2021
    Applicant: FUJIFILM Corporation
    Inventors: Takuto KUROKAWA, Naoki SANO, Norihito KASADA
  • Patent number: 11069377
    Abstract: Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is 0.04 ?m to 0.08 ?m, and an absolute value ?N of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.
    Type: Grant
    Filed: March 27, 2020
    Date of Patent: July 20, 2021
    Assignee: FUJIFILM Corporation
    Inventors: Takahiro Iwamoto, Hidemasa Hosoda, Norihito Kasada, Takuto Kurokawa
  • Patent number: 11062732
    Abstract: The magnetic tape includes a non-magnetic support; a magnetic layer including a ferromagnetic powder and a binding agent on one surface of the non-magnetic support; and a back coating layer including a non-magnetic powder and a binding agent on the other surface of the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the back coating layer is equal to or smaller than 7.0 nm, and a difference between a spacing Safter measured by optical interferometry regarding the surface of the back coating layer after methyl ethyl ketone cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the back coating layer before methyl ethyl ketone cleaning is greater than 0 nm and equal to or smaller than 30.0 nm.
    Type: Grant
    Filed: March 28, 2019
    Date of Patent: July 13, 2021
    Assignee: FUJIFILM Corporation
    Inventors: Eiki Ozawa, Takuto Kurokawa
  • Publication number: 20210090602
    Abstract: The magnetic recording medium includes: a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which a difference between a spacing measured on a surface of the back coating layer by optical interferometry under a pressure of 0.5 atm after n-hexane cleaning and a spacing measured on the surface of the back coating layer by optical interferometry under a pressure of 13.5 atm after n-hexane cleaning is 12 nm or more.
    Type: Application
    Filed: September 18, 2020
    Publication date: March 25, 2021
    Applicant: FUJIFILM Corporation
    Inventors: Naoki SANO, Takuto KUROKAWA, Eiki OZAWA, Norihito KASADA, Megumi NAKANO
  • Publication number: 20210090600
    Abstract: The magnetic recording medium includes a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which a difference between a spacing measured on a surface of the back coating layer by optical interferometry under a pressure of 0.5 atm after n-hexane cleaning and a spacing measured on the surface of the back coating layer by optical interferometry under a pressure of 13.5 atm after n-hexane cleaning is 3 nm or less.
    Type: Application
    Filed: September 16, 2020
    Publication date: March 25, 2021
    Applicant: FUJIFILM Corporation
    Inventors: Takuto KUROKAWA, Naoki SANO, Norihito KASADA, Eiki OZAWA, Megumi NAKANO