Patents Assigned to Powdertech Co., Ltd.
  • Publication number: 20120251191
    Abstract: Object of the present invention is to provide a resin-coated carrier for an electrophotographic developer with reduced carrier weight, carrier beads carry over is prevented, and further, excellent in carrier strength and stable charging property in endurance printing. To achieve the object, the carrier having a coated resin layer on the surface of a porous ferrite core material and the pore volume and the peak pore size of the porous ferrite core material are 55 to 160 mm3/g and 0.2 to 0.7 ?m, respectively, and an electrophotographic developer using the resin-coated carrier is adopted.
    Type: Application
    Filed: March 30, 2012
    Publication date: October 4, 2012
    Applicant: POWDERTECH CO., LTD.
    Inventors: Takao SUGIURA, Tetsuya IGARASHI
  • Patent number: 8247148
    Abstract: Employed are a resin-coated ferrite carrier for an electrophotographic developer including a ferrite carrier core material having a BET specific surface area of 900 to 5,000 cm2/g and an apparent density of 2.30 to 2.80 g/cm3, and the electrophotographic developer using this resin-coated ferrite carrier.
    Type: Grant
    Filed: February 22, 2008
    Date of Patent: August 21, 2012
    Assignee: Powdertech Co., Ltd.
    Inventors: Kanao Kayamoto, Issei Shinmura
  • Patent number: 8187781
    Abstract: Employed are a resin-filled ferrite carrier for an electrophotographic developer filled with a resin in voids of a porous ferrite core material, wherein the resin filled in the voids is a silicone resin which has a softening point of 40° C. or above and is cured at or above such softening point, and the filled amount is 7 to 30 parts by weight based on 100 parts by weight of the core material, a method for producing thereof band an electrophotographic developer using this ferrite carrier.
    Type: Grant
    Filed: March 4, 2008
    Date of Patent: May 29, 2012
    Assignee: Powdertech Co., Ltd.
    Inventors: Hiromichi Kobayashi, Takao Sugiura
  • Patent number: 8168364
    Abstract: A resin-filled carrier for an electrophotographic developer obtained by filling resin into voids of a porous ferrite core material, wherein the porous ferrite core material has a pore volume of 0.04 to 0.16 mL/g and a peak pore size of 0.9 to 2.0 ?m, and an electrophotographic developer using this resin-filled carrier.
    Type: Grant
    Filed: March 13, 2009
    Date of Patent: May 1, 2012
    Assignee: Powdertech Co., Ltd.
    Inventors: Takao Sugiura, Takeshi Gondo, Hiromichi Kobayashi
  • Publication number: 20120076551
    Abstract: An object of the present invention is to provide a resin-coated ferrite carrier comprising a carrier core material having a small particle size, a high sphericity and surface uniformity, and a low standard deviation, a process for producing the carrier, and an electrophotographic developer comprising the resin-coated ferrite carrier and having a high image quality and excellent durability. For achieving the above object, there is provided a resin-coated carrier for an electrophotographic developer characterized by comprising spherical ferrite particles having an average particle size of 20 to 50 ?m, a surface uniformity of 90% or more, an average sphericity of 1 to 1.3 and a sphericity standard deviation of 0.15 or less, a process for producing the carrier, and an electrophotographic developer comprising the resin-coated carrier.
    Type: Application
    Filed: December 7, 2011
    Publication date: March 29, 2012
    Applicant: POWDERTECH CO., LTD.
    Inventors: Kanao KAYAMOTO, Hironori HOJO, Toshio HONJO
  • Patent number: 8092971
    Abstract: An object of the present invention is to provide a resin-coated ferrite carrier comprising a carrier core material having a small particle size, a high sphericity and surface uniformity, and a low standard deviation, a process for producing the carrier, and an electrophotographic developer comprising the resin-coated ferrite carrier and having a high image quality and excellent durability. For achieving the above object, there is provided a resin-coated carrier for an electrophotographic developer characterized by comprising spherical ferrite particles having an average particle size of 20 to 50 ?m, a surface uniformity of 90% or more, an average sphericity of 1 to 1.3 and a sphericity standard deviation of 0.15 or less, a process for producing the carrier, and an electrophotographic developer comprising the resin-coated carrier.
    Type: Grant
    Filed: November 25, 2004
    Date of Patent: January 10, 2012
    Assignee: Powdertech Co., Ltd.
    Inventors: Kanao Kayamoto, Hironori Hojo, Toshio Honjo
  • Publication number: 20120003579
    Abstract: There are provided a ferrite carrier core material for an electrophotographic developer, which contain 10 to 30% by weight of Mn, 1.0 to 3.0% by weight of Mg, 0.3 to 1.5% by weight of Ti and 40 to 60% by weight of Fe, a ferrite carrier for an electrophotographic developer obtained by coating the ferrite core material, and an electrophotographic developer using the ferrite carrier.
    Type: Application
    Filed: June 16, 2011
    Publication date: January 5, 2012
    Applicant: Powdertech Co., Ltd.
    Inventors: Toru Iwata, Koji Aga
  • Patent number: 8039190
    Abstract: A carrier core material for an electrophotographic developer including Li ferrite, maghemite, and Fe3O4, wherein a part thereof is substituted with Mn, Li content is 1 to 2.5% by weight, Mn content is 2 to 7.5% by weight, and silicon content is 25 to 10,000 ppm, the following equation (1) is satisfied when respective integrated strengths of spinel crystal structure (110), (210), (211), and (311) faces in X-ray diffraction are respectively I110, I210, I211, and I311, a resistivity R50 of 50 V across a 6.5 mm gap is 5×107 to 7×108?, and a resistivity R1000 of 1,000 V across a 6.5 mm gap is 1×107 to 8×108?. 2<100×(I110+I210+I211)/I311<14??(1).
    Type: Grant
    Filed: March 6, 2009
    Date of Patent: October 18, 2011
    Assignees: Mitsui Mining & Smelting Co., Ltd., Powdertech Co., Ltd.
    Inventors: Yasunori Tabira, Koji Aga, Tomoyuki Suwa
  • Publication number: 20110244388
    Abstract: There is provided a resin-coated carrier for an electrophotographic developer, including: a carrier core particle; and a coating resin layer comprising a silicone resin or a modified silicone resin formed on a surface of the carrier core particle, wherein a titanium-ethyl acetoacetate chelate or a titanium-octylene glycol chelate is contained in the coating resin layer as a titanium chelate, and wherein the content of the titanium-ethyl acetoacetate chelate or the titanium-octylene glycol chelate is 5.0 to 50.0% by weight based on coating resin solids. There is also provided an electrophotographic developer using the resin-coated carrier.
    Type: Application
    Filed: March 25, 2011
    Publication date: October 6, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Tetsuya UEMURA, Tomoaki KOBAYASHI, Masashi AOKI
  • Publication number: 20110244389
    Abstract: Disclosed are a ferrite carrier core material for an electrophotographic developer including a ferrite particle having an apparent density of 2.30 to 2.80 g/cm3, a BET specific surface area of 0.09 to 0.70 m2/g and an average degree of circularity of 0.90 or more, wherein the Cl concentration of the ferrite carrier core material measured by an elution method is 0.1 to 100 ppm, a ferrite carrier for an electrophotographic developer obtained by coating the surface of the ferrite carrier core material with a resin, and methods for producing the ferrite carrier core material and the ferrite carrier, and an electrophotographic developer using the ferrite carrier.
    Type: Application
    Filed: March 25, 2011
    Publication date: October 6, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Takashi KOJIMA, Tetsuya UEMURA
  • Patent number: 8026033
    Abstract: Disclosed are a ferrite carrier for electrophotographic developer and an electrophotographic developer using the ferrite carrier, wherein: the ferrite carrier is a composite ferrite composed of Li and Mg; when the composition of the ferrite is calculated as a mixture of a Li ferrite having a stoichiometric composition and a Mg ferrite having a stoichiometric composition, the excessive amount of Fe2O3 is less than 5 mol %, or the total excessive amount of Li2O and MgO is less than 1 mol %; the content of the elements other than Li, Mg, Fe and O is 2 % by weight or less; and further, the content of Mn in terms of element is 1000 to 9000 ppm.
    Type: Grant
    Filed: January 16, 2008
    Date of Patent: September 27, 2011
    Assignee: Powdertech Co., Ltd.
    Inventors: Hiromichi Kobayashi, Takao Sugiura, Kanao Kayamoto
  • Publication number: 20110212399
    Abstract: There is provided a ferrite core material for an electrophotographic developer, the ferrite core material having a ferrite particle composition represented by the formula (1) shown below, containing SrO replacing a part of (MnO) and/or (MgO) in the formula (1) shown below, and having a Cl concentration of 0.1 to 100 ppm, as measured by an elution method of the ferrite core material: (MnO)x(MgO)y(Fe2O3)z ??(1) wherein x=35 to 45 mol %, y=5 to 15 mol %, z=40 to 60 mol %, and x+y+z=100 mol %.
    Type: Application
    Filed: February 3, 2011
    Publication date: September 1, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Tomoyuki SUWA, Toru IWATA, Koji AGA
  • Publication number: 20110195357
    Abstract: Disclosed are a resin-filled ferrite carrier core material for an electrophotographic developer, including a porous ferrite particle, wherein the composition of the porous ferrite particle is represented by the following formula (1), and part of (MgO) and/or (Fe2O3) in the following formula (1) is replaced with SrO; a ferrite carrier obtained by filling a resin in the voids of the ferrite carrier core material; and an electrophotographic developer using the ferrite carrier: ( MgO ) × ( Fe 2 ? O 3 ) ? y ? ( x = 10 ? ? mol ? ? % ? ? or ? ? more ? ? and ? ? less ? ? than ? ? 25 ? ? mol ? ? % y = exceeding ? ? 75 ? ? mol ? ? % ? ? and ? ? 90 ? ? mol ? ? % ? ? or ? ? less x + y = 100 ? ? mol ? ? % ) ( 1 )
    Type: Application
    Filed: February 2, 2011
    Publication date: August 11, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Takao SUGIURA, Takashi HIKICHI, Hiromichi KOBAYASHI
  • Publication number: 20110183253
    Abstract: A core material of a ferrite carrier for an electrophotographic developer, the core material being composed of a ferrite particle containing at least one or more temperature compensation-type dielectric components selected from Mg2TiO4, MgTiO3 and MgTi2O4, a ferrite carrier for an electrophotographic developer, the ferrite carrier being prepared by coating a surface of the carrier core material with a resin, and an electrophotographic developer using the ferrite carrier.
    Type: Application
    Filed: December 8, 2010
    Publication date: July 28, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Koji AGA, Toru IWATA
  • Publication number: 20110129772
    Abstract: A porous ferrite core material for an electrophotographic developer, the porous ferrite core material including Mg in a content of 0.3 to 3% by weight, Ti in a content of 0.4 to 3% by weight and Fe in a content of 60 to 70% by weight, and the porous ferrite core material having a pore volume of 0.04 to 0.16 ml/g, a peak pore size of 0.4 to 1.6 ?m, a saturation magnetization of 40 to 80 Am2/kg, a remanent magnetization of less than 7 Am2/kg and a coercive force of less than 43 A/m; a resin-filled ferrite carrier for an electrophotographic developer obtained by filling a resin in the voids of the porous ferrite core material; and an electrophotographic developer using the ferrite carrier.
    Type: Application
    Filed: October 19, 2010
    Publication date: June 2, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Toru IWATA, Koji AGA
  • Publication number: 20110097811
    Abstract: It is an object of the present invention to provide: an oxygen indicator aqueous solution for an oxygen detector that has high heat resistance, can be stored at room temperature, and can maintain an excellent ability to detect oxygen, regardless of the atmospheric temperature; an oxygen detector; and a method for manufacturing an oxygen detector. In order to achieve this object, there is provided an oxygen indicator aqueous solution for an oxygen detector that is an aqueous solution comprising reducing saccharides, a basic substance, and a redox dye reduced by the reducing saccharides, the aqueous solution comprising, as the reducing saccharides, a monosaccharide as a first component and a reducing trisaccharide as a second component. In addition, there is provided a manufacturing method preferred for the manufacturing of the oxygen detector.
    Type: Application
    Filed: October 19, 2010
    Publication date: April 28, 2011
    Applicant: POWDERTECH CO., LTD.
    Inventors: Ryuichi KODAMA, Mitsuyuki SATO
  • Patent number: 7921798
    Abstract: The oxygen detecting device (10) of the present invention includes an oxygen detector sheet having a sheet carrier (13) having a porous inorganic material filled therein which has been impregnated with an oxygen detecting fluid, and a film (11) having a predetermined oxygen transmittance for covering and sealing the sheet carrier (13). Since the sheet having the porous inorganic material filled therein is adopted, the oxygen detecting device has an excellent light resistance, leading to clear recognition of coloration for a long period of time. Because of excellent light resistance, the device keeps excellent property even after long exposure to a fluorescent lamp in a display case for displaying foods. Thus the device is suitable for checking quality of commercial products.
    Type: Grant
    Filed: July 26, 2005
    Date of Patent: April 12, 2011
    Assignee: Powdertech Co., Ltd.
    Inventors: Ryuichi Kodama, Hiroshi Endo, Toshitaka Wada, Shigeru Tanaka
  • Patent number: 7914715
    Abstract: A granulating method for forming a particle with a continuous ink-jet method using a liquid material, in which the liquid material containing a solid component and a binder component is supplied into one or more ink-jet nozzles of a continuous ink-jet device, a droplet is formed by having the supplied liquid material flow out the ink-jet nozzle, the droplet is carried in to drying means for drying the droplet, and the carried droplet is dried so as to obtain a granulated particle(s), the granulated particle(s) and a granulating device.
    Type: Grant
    Filed: January 17, 2007
    Date of Patent: March 29, 2011
    Assignee: Powdertech Co., Ltd.
    Inventors: Koji Aga, Hiromichi Kobayashi
  • Patent number: 7906265
    Abstract: A ferrite carrier for an electrophotographic developer having a compression breaking strength of 150 MPa or more, a rate of compressive change of 15.0% or more and a shape factor SF-1 of 100 to 125, a method for producing the same, and an electrophotographic developer containing the ferrite carrier.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: March 15, 2011
    Assignee: Powdertech Co., Ltd.
    Inventors: Tomoyuki Suwa, Tsuyoshi Itagoshi
  • Patent number: 7897317
    Abstract: The present invention provides a method for producing a core material of an electrophotographic ferrite carrier, by charging a raw powder with an average particle size of 20 to 50 ?m obtained by preparing raw materials for ferrite into a combustion flame along with a carrier gas for the raw powder, thermal-spraying the powder in atmospheric air to ferritize the powder, subsequently rapidly solidifying the thermal-sprayed particle, and sampling and collecting the particle, wherein the method satisfies the conditions comprising the following (1) to (3): (1) a mixture gas of propane and oxygen is used for the combustion flame for the thermal spraying, and a volumetric ratio of the propane to the oxygen is 1:3.5 to 6.0; (2) the carrier gas for the raw powder is air, nitrogen, oxygen or a mixture gas thereof, and the ratio (a/b) of a charged amount (a) of a raw powder (kg/hr) to a charged amount (b) of the carrier gas (kg/hr) for the raw powder is 4.
    Type: Grant
    Filed: February 21, 2008
    Date of Patent: March 1, 2011
    Assignee: Powdertech Co., Ltd
    Inventors: Issei Shinmura, Kanao Kayamoto