Patents Assigned to Dowa IP Creation Co., Ltd.
  • Publication number: 20210132520
    Abstract: According to the present invention, there is provided a carrier core material that is formed of ferrite particles in which 48 to 52 mass % of Fe, 16 to 22 mass % of Mn, 1.0 to 3.5 mass % of Mg and 0.05 to 0.5 mass % of Ca are included, and when an electrical resistance value with an applied voltage of 500 V in an environment (in an L/L environment) in which the temperature is 10° C. and the relative humidity is 35% is RL (?·cm), and an electrical resistance value with an applied voltage of 500 V in an environment (in an H/H environment) in which the temperature is 30° C. and the relative humidity is 70% is RH (?·cm), formula (1) below is satisfied. 0.1?(log RL?log RH)?0.
    Type: Application
    Filed: March 15, 2018
    Publication date: May 6, 2021
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Takeshi KAWAUCHI, Yohei ISHIKAWA, Hiroyuki MIYANO
  • Patent number: 10915034
    Abstract: A carrier core material is represented by a composition formula MXFe3-XO4 (where M is at least one type of metal element selected from Mg, Mn, Ca, Ti, Cu, Zn and Ni, 0<X<1), in which part of M and/or Fe is substituted with Sr and formed of ferrite particles, and in the carrier core material, a Sr content is equal to or more than 2500 ppm but equal to or less than 12000 ppm, the amount of Sr eluted with pure water at a temperature of 25° C. is equal to or less than 50 ppm, an apparent density is equal to or more than 1.85 g/cm3 but equal to or less than 2.25 g/cm3 and magnetization ?1k when a magnetic field of 79.58×103 A/m (1000 oersteds) is applied is equal to or more than 63 Am2/kg but equal to or less than 75 Am2/kg.
    Type: Grant
    Filed: March 15, 2018
    Date of Patent: February 9, 2021
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventor: Shou Ogawa
  • Patent number: 10907257
    Abstract: In a projection material for mechanical plating, a steel particle is used as a core, and the surrounding surface thereof is coated with a zinc alloy in which the content of Al is more than 5% by mass but equal to or less than 16% by mass, the content of Mg is equal to or more than 5.5% by mass but equal to or less than 15% by mass and the remaining portion is Zn and an impurity, and the content of Fe is equal to or more than 3% by mass but equal to or less than 80% by mass. In this way, the corrosion resistance of a zinc-based coating itself formed in mechanical plating is remarkably enhanced without dependence on protective coating formation treatment such as chromate treatment.
    Type: Grant
    Filed: July 19, 2016
    Date of Patent: February 2, 2021
    Assignees: DOWA IP CREATION CO., LTD., HONDA MOTOR CO., LTD.
    Inventors: Takashi Fujiwara, Naohisa Okamoto, Kenji Kimura, Tsutomu Miyadera
  • Patent number: 10698330
    Abstract: A carrier core material formed with ferrite particles, the skewness Rsk of the particle is equal to or more than ?0.40 but equal to or less than ?0.20, and the kurtosis Rku of the particle is equal to or more than 3.20 but equal to or less than 3.50. Here, the maximum height Rz of the particle is equal to or more than 2.20 ?m but equal to or less than 3.50 ?m. Moreover, the ferrite particle contains at least either of Mn and Mg elements. In this way, cracking or chipping in a concave-convex portion of a particle surface is unlikely to occur, and moreover, the amount of coating resin used can be reduced without properties such as electrical resistance being lowered.
    Type: Grant
    Filed: March 28, 2017
    Date of Patent: June 30, 2020
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yuki Kitahara, Shou Ogawa
  • Publication number: 20190391506
    Abstract: A carrier core material is represented by a composition formula MXFe3-XO4 (where M is at least one type of metal element selected from Mg, Mn, Ca, Ti, Cu, Zn and Ni, 0<X<1), in which part of M and/or Fe is substituted with Sr and formed of ferrite particles, and in the carrier core material, a Sr content is equal to or more than 2500 ppm but equal to or less than 12000 ppm, the amount of Sr eluted with pure water at a temperature of 25° C. is equal to or less than 50 ppm, an apparent density is equal to or more than 1.85 g/cm3 but equal to or less than 2.25 g/cm3 and magnetization ?1k when a magnetic field of 79.58×103 A/m (1000 oersteds) is applied is equal to or more than 63 Am2/kg but equal to or less than 75 Am2/kg.
    Type: Application
    Filed: March 15, 2018
    Publication date: December 26, 2019
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventor: Shou OGAWA
  • Publication number: 20190064688
    Abstract: A carrier core material formed with ferrite particles, the skewness Rsk of the particle is equal to or more than ?0.40 but equal to or less than ?0.20, and the kurtosis Rku of the particle is equal to or more than 3.20 but equal to or less than 3.50. Here, the maximum height Rz of the particle is equal to or more than 2.20 ?m but equal to or less than 3.50 ?m. Moreover, the ferrite particle contains at least either of Mn and Mg elements. In this way, cracking or chipping in a concave-convex portion of a particle surface is unlikely to occur, and moreover, the amount of coating resin used can be reduced without properties such as electrical resistance being lowered.
    Type: Application
    Filed: March 28, 2017
    Publication date: February 28, 2019
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yuki KITAHARA, Shou OGAWA
  • Patent number: 10185238
    Abstract: A carrier core material is provided that is formed with ferrite particles which can uniformly adhere a coupling agent to the entire surface. A carrier core material is formed with ferrite particles, and the powder pH of the ferrite particles is equal to or more than 9. Here, the ferrite particles are preferably formed of Mn ferrite or Mn—Mg ferrite. The ferrite particles preferably contain 45 wt % or more but 65 wt % or less of Fe, 15 wt % or more but 30 wt % or less of Mn and 5 wt % or less of Mg.
    Type: Grant
    Filed: July 21, 2017
    Date of Patent: January 22, 2019
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yuto Kamai, Shinya Sasaki
  • Publication number: 20180282875
    Abstract: In a projection material for mechanical plating, a steel particle is used as a core, and the surrounding surface thereof is coated with a zinc alloy in which the content of Al is more than 5% by mass but equal to or less than 16% by mass, the content of Mg is equal to or more than 5.5% by mass but equal to or less than 15% by mass and the remaining portion is Zn and an impurity, and the content of Fe is equal to or more than 3% by mass but equal to or less than 80% by mass. In this way, the corrosion resistance of a zinc-based coating itself formed in mechanical plating is remarkably enhanced without dependence on protective coating formation treatment such as chromate treatment.
    Type: Application
    Filed: July 19, 2016
    Publication date: October 4, 2018
    Applicants: DOWA IP CREATION CO., LTD., HONDA MOTOR CO., LTD.
    Inventors: Takashi FUJIWARA, Naohisa OKAMOTO, Kenji KIMURA, Tsutomu MIYADERA
  • Patent number: 10088764
    Abstract: A carrier core material includes, a main component, a material represented by a composition formula MnXMYFe3?(X+Y)O4 (where M is selected from Mg, Ti, Cu, Zn and Ni, 0<X, 0?Y, 0<X+Y<1), in which 0.1 to 1.0 mol % of at least one of Sr element and Ca element is contained as the total amount by conversion to SrO or CaO and in which the frequency of a grain whose length RSm is equal or more than 8.0 ?m among grains appearing on the surface of particles of the carrier core material is equal to or less than 2.0 number percent. In this way, the degradation of a carrier caused by long-term use such as the separation of a coating resin is significantly reduced, stable charging performance is maintained and the cracking or chipping of the particles is reduced.
    Type: Grant
    Filed: March 22, 2016
    Date of Patent: October 2, 2018
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yuto Kamai, Takeshi Kawauchi
  • Patent number: 9964878
    Abstract: A carrier core material is represented by a composition formula MxFe3-xO4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X?1), in which 5 to 20 number percent of bound particles where 2 to 5 spherical particles are bound together are contained and in which the maximum peak-to-trough depth Rz of the surface of normal spherical particles other than the bound particles is equal to or more than 1.5 ?m but equal to or less than 2.1 ?m. In this way, it is possible to increase the amount of toner supplied to a development region, and the surface of a photosensitive member is prevented from being scratched by a magnetic brush.
    Type: Grant
    Filed: March 1, 2016
    Date of Patent: May 8, 2018
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yohei Ishikawa, Shinya Sasaki
  • Publication number: 20180107129
    Abstract: A carrier core material is represented by a composition formula MxFe3-xO4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X?1), in which 5 to 20 number percent of bound particles in which 2 to 5 spherical particles are bound together are contained, and in which the absolute value of a difference between lattice constants before and after milling which are calculated from a peak position of plane indices in a powder X-ray diffraction pattern is equal to or less than 0.005. In this way, it is possible to increase the amount of toner supplied to a development region, and even when cracking or chipping occurs in the carrier core material, an image failure such as black spots or white spots is prevented from being generated.
    Type: Application
    Filed: March 3, 2016
    Publication date: April 19, 2018
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yohei ISHIKAWA, Shinya SASAKI
  • Publication number: 20180052405
    Abstract: A carrier core material is represented by a composition formula MxFe3-xO4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X?1), in which 5 to 20 number percent of bound particles where 2 to 5 spherical particles are bound together are contained and in which the maximum peak-to-trough depth Rz of the surface of normal spherical particles other than the bound particles is equal to or more than 1.5 ?m but equal to or less than 2.1 ?m. In this way, it is possible to increase the amount of toner supplied to a development region, and the surface of a photosensitive member is prevented from being scratched by a magnetic brush.
    Type: Application
    Filed: March 1, 2016
    Publication date: February 22, 2018
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yohei ISHIKAWA, Shinya SASAKI
  • Publication number: 20180046103
    Abstract: A carrier core material includes, a main component, a material represented by a composition formula MnXMYFe3-(X+Y)O4 (where M is selected from Mg, Ti, Cu, Zn and Ni, 0<X, 0?Y, 0<X+Y<1), in which 0.1 to 1.0 mol % of at least one of Sr element and Ca element is contained as the total amount by conversion to SrO or CaO and in which the frequency of a grain whose length RSm is equal or more than 8.0 ?m among grains appearing on the surface of particles of the carrier core material is equal to or less than 2.0 number percent. In this way, the degradation of a carrier caused by long-term use such as the separation of a coating resin is significantly reduced, stable charging performance is maintained and the cracking or chipping of the particles is reduced.
    Type: Application
    Filed: March 22, 2016
    Publication date: February 15, 2018
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yuto KAMAI, Takeshi KAWAUCHI
  • Publication number: 20180024455
    Abstract: A carrier core material is provided that is formed with ferrite particles which can uniformly adhere a coupling agent to the entire surface. A carrier core material is formed with ferrite particles, and the powder pH of the ferrite particles is equal to or more than 9. Here, the ferrite particles are preferably formed of Mn ferrite or Mn—Mg ferrite. The ferrite particles preferably contain 45 wt % or more but 65 wt % or less of Fe, 15 wt % or more but 30 wt % or less of Mn and 5 wt % or less of Mg.
    Type: Application
    Filed: July 21, 2017
    Publication date: January 25, 2018
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Yuto KAMAI, Shinya SASAKI
  • Patent number: 9740129
    Abstract: Ferrite particles have, as a main component, a material represented by a composition formula MxFe3?xO4 (where M is at least one type of metal selected from a group made of Mg, Mn, Ca, Ti, Cu, Zn, Sr and Ni, 0<x<1), where the maximum height Rz of the particles falls within a range of 1.40 ?m to 1.90 ?m, and the degree of distortion Rsk of the particles falls within a range of ?0.25 to ?0.07. In this way, when the ferrite particles are used as the carrier of an electrophotographic image forming apparatus, even if an image formation speed is increased, the occurrence of a failure is reduced for a long period of time.
    Type: Grant
    Filed: October 29, 2014
    Date of Patent: August 22, 2017
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Shinya Sasaki, Yohei Ishikawa, Haruka Seki
  • Patent number: 9651886
    Abstract: This invention is directed to a method for manufacturing carrier core particles for electrophotographic developer containing iron, manganese, and calcium as a core composition. The method includes (A) a mixing step of mixing an iron-containing raw material, a manganese-containing raw material, and a calcium-containing raw material to prepare a mixture thereof, (C) a granulation step of granulating the mixture after the mixing step, and (D) a firing step of firing a powdery material, which is obtained by granulating the mixture in the granulation step, at a predetermined temperature to form a magnetic phase. The calcium-containing raw material is provided in a granular form, and primary particles of the calcium-containing raw material have a volume mean diameter of 1 ?m or less.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: May 16, 2017
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Takeshi Kawauchi, Tomohide Iida
  • Patent number: 9507285
    Abstract: There are provided ferrite particles in which Mn ferrite is used as the main phase and which contain Sr ferrite, where the degree of projections and recesses in the surface of the particles falls within a range of 2.5 to 4.5 ?m, and the standard deviation of the size of grains appearing on the surface of the particles falls within a range of 1.5 to 3.5 ?m. In this way, a coating resin is left on the surface of the particles even after long-term use and thus a decrease in the charging property is reduced.
    Type: Grant
    Filed: February 26, 2014
    Date of Patent: November 29, 2016
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Takeshi Kawauchi, Shou Ogawa, Yukihiro Matsuda
  • Publication number: 20160266510
    Abstract: There are provided ferrite particles that have, as a main component, a material represented by a composition formula MxFe3-xO4 (where M is at least one type of metal selected from a group consisting of Mg, Mn, Ca, Ti, Cu, Zn, Sr and Ni, 0<x<1), where the maximum height Rz of the particles falls within a range of 1.40 to 1.90, and the degree of distortion Rsk of the particles falls within a range of ?0.25 to ?0.07. In this way, when the ferrite particles are used as the carrier of an electrophotographic image forming apparatus, even if an image formation speed is increased, the occurrence of a failure is reduced for a long period of time.
    Type: Application
    Filed: October 29, 2014
    Publication date: September 15, 2016
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Shinya SASAKI, Yohei ISHIKAWA, Haruka SEKI
  • Patent number: 9429862
    Abstract: A method for manufacturing carrier core particles for electrophotographic developer that include manganese, magnesium, and iron as a core composition. The method includes a granulation step (A) of granulating a mixture of raw materials containing manganese, magnesium, and iron with a reducing agent added at a ratio of 0.10% to 1.00% by mass to a total mass of the raw materials containing manganese, magnesium, and iron, and a firing step of firing the granular material granulated in the granulation step. The firing step includes a first heating step (C) of applying heat at a constant temperature ranging from 500° C. to 800° C. in an atmosphere with an oxygen concentration of 1000 ppm to 15000 ppm for a predetermined period of time and a second heating step (D) of applying heat at a temperature higher than 800° C. for a predetermined period of time after the first heating step.
    Type: Grant
    Filed: October 16, 2015
    Date of Patent: August 30, 2016
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventor: Takeshi Kawauchi
  • Patent number: 9329514
    Abstract: A carrier core particle for an electrophotographic developer includes a composition expressed by a general formula: MnxFe3?xO4+y (0<x?1, 0<y), a full width at half maximum z of the most intense peak (311) plane in a powder X-ray diffraction pattern satisfying 0.16 (degree)?z, and a magnetization of 50 emu/g or higher in an external magnetic field of 1000 Oe.
    Type: Grant
    Filed: September 25, 2014
    Date of Patent: May 3, 2016
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Takeshi Kawauchi, Sho Ogawa