Patents Assigned to Powdertech Co., Ltd.
  • Publication number: 20070180661
    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: Application
    Filed: January 17, 2007
    Publication date: August 9, 2007
    Applicant: POWDERTECH CO., LTD.
    Inventors: Koji Aga, Hiromichi Kobayashi
  • Publication number: 20070154833
    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: November 25, 2004
    Publication date: July 5, 2007
    Applicant: POWDERTECH CO., LTD.
    Inventors: Kanao Kayamoto, Hironori Hojo, Toshio Honjo
  • Publication number: 20070141502
    Abstract: A ferrite carrier core material for electrophotography having a homogeneous composition, a certain surface property, a favorable fluidity, a high magnetization and a low resistance, and a ferrite carrier for electrophotography methods for producing them, and an electrophotographic developer using the ferrite carrier-core material, which exhibits a fast charge rising and a stable charge quantity with time, are provided. A ferrite carrier core material for electrophotography whose surface is divided by grooves or streaks into 2 to 50 regions per 10 ?m and which has a manganese ferrite as a main component, and a method for producing the ferrite carrier core material for electrophotography using an Fe—Mn composite oxide as the raw material, and a method for producing a ferrite carrier for electrophotography are employed.
    Type: Application
    Filed: June 5, 2006
    Publication date: June 21, 2007
    Applicant: POWDERTECH CO., LTD.
    Inventors: Koji Aga, Takeshi Naito, Tetsuya Igarashi, Toshio Honjo
  • Publication number: 20070048649
    Abstract: A carrier for an electrophotographic developer which is used as an electrophotographic developer in a mixture with a toner and which secures sufficiently the image density and can maintain high-quality images for a long period, and an electrophotographic developer using the carrier, are provided. A resin-filled ferrite carrier for electrophotographic developer obtained by filling, with a resin, avoid of a porous ferrite core whose void continues from the surface to reach the interior of the core, the carrier comprising a plurality of three-dimensional laminate structures in which resin layers and ferrite layers are alternately present, and an electrophotographic developer including the carrier and a toner, are employed.
    Type: Application
    Filed: August 25, 2006
    Publication date: March 1, 2007
    Applicant: POWDERTECH CO., LTD.
    Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Tomoyuki Suwa, Toshio Honjo
  • Patent number: 7183033
    Abstract: A carrier core material for an electrophotographic developing agent, which comprises 100 parts by weight of a ferrite component represented by a formula (A) and 0.1 to 5.0 parts by weight of ZrO2 that is present in the ferrite component without forming a solid solution, and which has a magnetization, at 1000(103/4?·A/m), of 65 to 85 Am2/kg and an electrical resistance, at an applied voltage of 1000 V, of 105 to 109 ?. (MnO)x(MgO)y(Fe2O3)z??(A) wherein x, y and z are each expressed in % by mol and are numbers satisfying the conditions of 40?x?60, 0.1?y?10 and x+y+z=100. Also disclosed is a two-component developing agent comprising a coated carrier, which is obtained by coating the above carrier core material with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed by the use of an alternating electric field, with the two-component developing agent.
    Type: Grant
    Filed: February 6, 2004
    Date of Patent: February 27, 2007
    Assignee: Powdertech Co., Ltd.
    Inventors: Issei Shinmura, Hiromichi Kobayashi, Tsuyoshi Itagoshi, Yuji Sato
  • Publication number: 20060269862
    Abstract: A ferrite core material for a resin-filled type carrier, and a resin-filled type carrier which is used as an electrophotographic developer by mixing a toner, sufficiently secure the image density, have no carrier adhesion and can maintain high-quality images over a long period, and an electrophotographic developer using the carrier, are provided. A ferrite core material for a resin-filled type carrier characterized in a void fraction of 10 to 60%, a resin-filled type carrier filled in the carrier core material with a resin, and an electrophotographic developer composed of the resin-filled type carrier and a toner, are provided.
    Type: Application
    Filed: May 31, 2006
    Publication date: November 30, 2006
    Applicant: POWDERTECH CO., LTD.
    Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Tomoyuki Suwa, Toshio Honjo
  • Publication number: 20060194137
    Abstract: It is contemplated to provide irregular shaped ferrite carrier which has a lower resistance, a high specific surface area, a low specific gravity and a longer operational life, and an electrophotographic developer comprising the ferrite carrier which prevents the toner scattering, has a high image density, and is responsive to high-speed and color imaging. The irregular shaped ferrite carrier is characterized in that the carrier particles are irregular shaped, and 40 percent by number or more of the particles have a rock candy sugar shape and/or an oyster shell shape, and that the shape factor (SF-1=R2/S×?/4×100, wherein R is a maximum length and S is a projected area.) is 140 to 250, and the distribution width (?) is 60 or less.
    Type: Application
    Filed: February 28, 2006
    Publication date: August 31, 2006
    Applicant: POWDERTECH CO., LTD.
    Inventors: Hiromichi Kobayashi, Toru Iwata, Toshio Honjo
  • Publication number: 20060141106
    Abstract: There is provided a method for controlling the quality of a product, characterized in that a product and an oxygen detecting agent having a predetermined sensitivity corresponding to the kind of the product and quality control conditions for the product are provided in combination and the quality of the product is controlled by taking advantage of such a phenomenon that, when a predetermined period of time corresponding to the kind of the product and the quality control conditions for the product has elapsed, the oxygen detecting agent undergoes a change in color as a result of the detection of the concentration of oxygen, which has infiltrated the oxygen detecting agent, by the oxygen detecting agent.
    Type: Application
    Filed: February 5, 2004
    Publication date: June 29, 2006
    Applicant: Powdertech Co., Ltd.
    Inventors: Ryuichi Kodama, Minoru Tamura, Kazuhiko Shinohara, Hiroshi Endo, Toshitaka Wada, Shigeru Tanaka
  • Publication number: 20060121386
    Abstract: A carrier for electrophotographic developer comprises a resin carrier core comprising a binder resin and magnetic powder dispersed in the binder resin, and a coating layer comprising a coating resin on a surface of the core, the binder resin being a silicone resin obtained by curing of a polysiloxane compound (A) having an epoxy group and a polysiloxane compound (B) having a group capable of reacting with the epoxy group, due to a ring-opening addition reaction; the binder resin containing a functional group which is an epoxy group and/or a group capable of reacting with an epoxy group; the coating resin containing a functional group capable of reacting with the functional group of the binder resin; the functional group of the coating resin and the functional group of the binder resin forming a chemical bond.
    Type: Application
    Filed: December 7, 2005
    Publication date: June 8, 2006
    Applicants: Mitsui Mining & Smelting Co., Ltd., Powdertech Co., Ltd.
    Inventors: Yoichi Kamikoriyama, Kenji Suzuoka, Takashi Nakashima, Kazuya Kinoshita, Yuji Sato, Hiromichi Kobayashi, Takeshi Gondo, Takashi Hikichi
  • Publication number: 20060121385
    Abstract: A resin-coated ferrite carrier having a uniform resin coating and emitting no offensive odors, etc., its production method, and an electrophotographic developer which comprises the resin-coated ferrite carrier, is excellent in the charge stability and image quality stability over a long period, causes less fogging of image or carrier adhesion, is favorable in the image density and environmental dependency, and can fully respond to high-speed and full-color imaging, are provided. The resin-coated ferrite carrier for the electrophotographic developer is characterized in that the surface of ferrite particles is coated with a mixed resin of a tetrafluoroethylene-hexafluoropropylene copolymer or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer and a polyamideimide resin, and that the mixed resin contains a silicon oxide.
    Type: Application
    Filed: November 14, 2005
    Publication date: June 8, 2006
    Applicant: POWDERTECH CO., LTD.
    Inventors: Tetsuya Uemura, Toshio Honjo, Kanao Kayamoto
  • Publication number: 20060003248
    Abstract: A ferrite carrier for the electrophotographic developer containing 40 to 500 ppm of zirconium; a method for preparing a ferrite carrier for the electrophotographic developer, comprising the steps for weighing, mixing, and pulverizing ferrite raw materials, and for granulating, drying, and firing the obtained slurry; wherein a zirconium raw material is added so that the zirconium content after firing becomes 40 to 500 ppm; and an electrophotographic developer using the ferrite carrier.
    Type: Application
    Filed: June 28, 2005
    Publication date: January 5, 2006
    Applicant: POWDERTECH CO., LTD.
    Inventors: Hiromichi Kobayashi, Kanao Kayamoto, Tadashi Harayama, Issei Shinmura, Toshio Honjo
  • Patent number: 6905806
    Abstract: A dry two-component developer for electrophotography comprising a carrier particle and a toner particle, wherein a toner water adsorption ratio (T) obtained by a following equation (1) for the toner particle ranges from 1.0 to 7.0 and a carrier water adsorption ratio (C) obtained by a following equation (2) is 20.0 or less, and a water adsorption ratio (T/C) expressed in a following equation (3) representing a relationship between the toner water adsorption ratio (T) and the carrier water adsorption ratio (C) is 5.0 or less; a toner water adsorption ratio (T)=a water adsorption amount (TH) of the toner particle/an N2 adsorption amount (TN) of the toner particle (1), a carrier water adsorption ratio (C)=a water adsorption amount (CH) of the carrier particle/an N2 adsorption amount (CN) of the carrier particle (2), and a water adsorption ratio (T/C)=a toner water adsorption ratio (T)/a carrier water adsorption ratio (C) (3).
    Type: Grant
    Filed: September 2, 2003
    Date of Patent: June 14, 2005
    Assignee: Powdertech Co., Ltd.
    Inventors: Takeshi Naito, Hiromichi Kobayashi, Tsuyoshi Itagoshi, Yuji Sato
  • Publication number: 20040248015
    Abstract: Provided are a carrier for electrophotography developers prepared with generating a slight amount of byproducts such as water, alcohol, etc, which carrier is free from release of a magnetic powder, has excellent mechanical strength and durability, and good environmental stability, and further can restrain occurrence of toner spent condition and has favorable fluidity and excellent capability of imparting charging to a toner, a two-component developer comprising the carrier and a method for forming an image using the developer.
    Type: Application
    Filed: June 4, 2004
    Publication date: December 9, 2004
    Applicants: MITSUI MINING & SMELTING CO., LTD., POWDERTECH CO., LTD.
    Inventors: Yoichi Kamikoriyama, Kenji Suzuoka, Takashi Nakashima, Kazuya Kinoshita, Yuji Sato, Hiromichi Kobayashi, Takeshi Gondo, Takashi Hikichi
  • Publication number: 20040229151
    Abstract: A carrier core material containing at least one metal oxide (MLO) having a melting point of not higher than 1000° C. and at least one metal oxide (MHO) having a melting point of not lower than 1800° C., wherein the metal (MH) for constituting the metal oxide (MHO) has an electrical resistivity of not less than 10−5 &OHgr;·cm. Also disclosed is a two-component developing agent comprising a coated carrier, which comprises the carrier core material coated with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed on a photosensitive member with the two-component developing agent using an alternating electric field. The carrier core material and the coated carrier have high magnetization and are free from occurrence of leakage of electric charge over a wide range of electric field from low electric field to high electric field.
    Type: Application
    Filed: February 6, 2004
    Publication date: November 18, 2004
    Applicant: POWDERTECH CO., LTD.
    Inventors: Hiromichi Kobayashi, Issei Shinmura, Tsuyoshi Itagoshi, Yuji Sato
  • Publication number: 20040043320
    Abstract: The present invention provides a dry two-component type developer for electrophotography comprising a carrier particle and a toner particle, wherein a toner water adsorption ratio (T) obtained by a following equation (1) for the toner particle ranges from 1.0 to 7.0 and a carrier water adsorption ratio (C) obtained by a following equation (2) is 20.0 or less, and a water adsorption ratio (T/C) expressed in a following equation (3) representing a relationship between the toner water adsorption ratio (T) and the carrier water adsorption ratio (C) is 5.
    Type: Application
    Filed: September 2, 2003
    Publication date: March 4, 2004
    Applicant: POWDERTECH CO., LTD.
    Inventors: Takeshi Naito, Hiromichi Kobayashi, Tsuyoshi Itagoshi, Yuji Sato
  • Patent number: 6686113
    Abstract: A resin-coated carrier to be mixed with a polymer toner obtained by suspension polymerization or emulsion polymerization to provide an electrophotographic developer, which exposes 2 to 20% of the surface area of the core thereof, the average exposed area ratio per exposed part of the core being 0.03% or less.
    Type: Grant
    Filed: June 19, 2002
    Date of Patent: February 3, 2004
    Assignee: Powdertech Co., Ltd.
    Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Takeshi Naito, Yuji Sato
  • Publication number: 20030186156
    Abstract: A resin-coated carrier for an electrophotographic developer and a process of producing the carrier. The carrier comprises a ferrite core mainly comprising iron oxide, primarily having a spinel structure, and having a volume average particle size of 20 to 45 &mgr;m and a resin coat, wherein the carrier has a magnetization of 65 to 80 emu/g in a magnetic field of 1 KOe, the core has an electric current value of 50 to 150 &mgr;A and a surface smoothness uniformity of 75% or higher, and the amount of the resin coat is 0.1 to 5.0% by weight based on the core.
    Type: Application
    Filed: March 21, 2003
    Publication date: October 2, 2003
    Applicant: POWDERTECH CO., LTD
    Inventors: Kanao Kayamoto, Issei Shinmura, Yuji Sato
  • Patent number: 6627369
    Abstract: A carrier for an electrophotographic developer which has a flowability index F1, represented by formula (1), of 63 to 75 sec/(50·cm3) and a flowability index F2, represented by formula (2), of 30 to 100 Oe·g/cm3: F1=AD×FR  (1) F2=AD×Hc  (2) wherein AD is an apparent density (g/cm3); FR is a flow rate (sec/50 g); and Hc is a coercive force (Oe).
    Type: Grant
    Filed: January 30, 2002
    Date of Patent: September 30, 2003
    Assignee: Powdertech Co., Ltd.
    Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Yasuhiko Kataoka, Yuji Sato
  • Patent number: 6582870
    Abstract: A carrier for an electrophotographic developer comprising spherical magnetic core particles which have a volume average particle size of 25 to 45 &mgr;m, an average void size of 10 to 20 &mgr;m, a volume based particle size distribution having less than 1% of 22 &mgr;m or smaller particles, a magnetization of 67 to 88 emu/g in a magnetic field of 1 kOe, and a difference of 10 emu/g or smaller in magnetization in a magnetic field of 1 kOe between scattered particles and remaining particles.
    Type: Grant
    Filed: January 15, 2002
    Date of Patent: June 24, 2003
    Assignee: Powdertech Co., Ltd.
    Inventors: Kanao Kayamoto, Issei Shinmura, Yuji Sato
  • Publication number: 20030091923
    Abstract: A resin-coated carrier to be mixed with a polymer toner obtained by suspension polymerization or emulsion polymerization to provide an electrophotographic developer, which exposes 2 to 20% of the surface area of the core thereof, the average exposed area ratio per exposed part of the core being 0.03% or less.
    Type: Application
    Filed: June 19, 2002
    Publication date: May 15, 2003
    Applicant: POWDERTECH CO., LTD.
    Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Takeshi Naito, Yuji Sato