The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 27, 2007
Filed:
Feb. 06, 2004
Issei Shinmura, Kashiwa, JP;
Hiromichi Kobayashi, Kashiwa, JP;
Tsuyoshi Itagoshi, Kashiwa, JP;
Yuji Sato, Kashiwa, JP;
Issei Shinmura, Kashiwa, JP;
Hiromichi Kobayashi, Kashiwa, JP;
Tsuyoshi Itagoshi, Kashiwa, JP;
Yuji Sato, Kashiwa, JP;
Powdertech Co., Ltd., , JP;
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 ZrOthat is present in the ferrite component without forming a solid solution, and which has a magnetization, at 1000(10/4π·A/m), of 65 to 85 Am/kg and an electrical resistance, at an applied voltage of 1000 V, of 10to 10Ω.(MnO)(MgO)(FeO)  (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. The carrier core material and the coated carrier have high magnetization and high resistance. According to the two-component developing agent of the invention, an excellent image can be formed.