Patents Assigned to Powertech Co., Ltd.
  • Patent number: 7964330
    Abstract: There are adopted an electrophotographic resin-coated ferrite carrier having a carrier core coated with a resin, wherein a product of an apparent density ? (g/cm3), average particle size d (?m) and BET specific surface area S (m2/g) of the carrier core satisfies the following condition, a method for producing the same, and an electrophotographic developer. 4.5??×d×S?8.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: June 21, 2011
    Assignee: Powertech Co., Ltd.
    Inventors: Issei Shinmura, Kanao Kayamoto
  • Patent number: 7144670
    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 ?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 ?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: Grant
    Filed: March 21, 2003
    Date of Patent: December 5, 2006
    Assignee: Powertech Co., Ltd.
    Inventors: Kanao Kayamoto, Issei Shinmura, Yuji Sato