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Title:
FERRITE CARRIER CORE MATERIAL FOR ELECTROPHOTOGRAPHIC DEVELOPERS, FERRITE CARRIER, AND MANUFACTURING PROCESSES FOR BOTH, AND ELECTROPHOTOGRAPHIC DEVELOPERS USING THE FERRITE CARRIER
Document Type and Number:
WIPO Patent Application WO/2012/105078
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide: a ferrite carrier core material for electrophotographic developers which have excellent electrification properties and which are less susceptible to carrier scattering caused by the fracture and/or chipping of core material and thus exhibit a long service life; a ferrite carrier; processes for producing both; and electrophotographic developers using the ferrite carrier. In order to achieve the purpose, employed are a ferrite carrier core material for electrophotographic developers and a ferrite carrier therefor, said core material having the characteristics: (1) the ferrite has a composition which contains 0.5 to 2.5wt% of Sr and in which the quantity of present Sr-Fe oxides satisfies a specific conditional expression; (2) the shape factor SF-2 has a specific frequency distribution; (3) the BET specific surface area is 0.15 to 0.30m2/g; (4) the median particle diameter (D50) is 20 to 35μm; and (5) the magnetization is 50 to 65Am2/kg. Also employed are manufacturing processes for both, and so on.

Inventors:
SUWA TOMOYUKI (JP)
IWATA TORU (JP)
AGA KOJI (JP)
Application Number:
JP2011/069435
Publication Date:
August 09, 2012
Filing Date:
August 29, 2011
Export Citation:
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Assignee:
POWDERTECH CO LTD (?2778557, JP)
SUWA TOMOYUKI (JP)
IWATA TORU (JP)
AGA KOJI (JP)
International Classes:
G03G9/107; G03G9/113
Foreign References:
JP2010243798A2010-10-28
JP2010055014A2010-03-11
JP2010181524A2010-08-19
JP2010039368A2010-02-18
JP2010181525A2010-08-19
JPH0822150A1996-01-23
JP2004004648A2004-01-08
JP2010039368A2010-02-18
JP2008096977A2008-04-24
JP2007271662A2007-10-18
JP2006267345A2006-10-05
Other References:
See also references of EP 2557457A4
Attorney, Agent or Firm:
YOSHIMURA, KATSUHIRO (?3300854, JP)
Katsuhiro Yoshimura (?3300854, JP)
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Claims: