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:
Jul. 14, 2015
Filed:
Aug. 29, 2011
Tomoyuki Suwa, Ibaraki, JP;
Toru Iwata, Saitama, JP;
Koji Aga, Chiba, JP;
POWDERTECH CO., LTD., Chiba, JP;
Abstract
It is an object of the present invention to provide a ferrite carrier core material and a ferrite carrier for an electrophotographic developer, which have an excellent charging property, hardly cause carrier scattering due to cracking and chipping of the core material, and have a prolonged life, and methods for manufacturing these, and an electrophotographic developer using the ferrite carrier. For this object, the ferrite carrier core material and a ferrite carrier for an electrophotographic developer, wherein (1) the ferrite composition contains 0.5 to 2.5% by weight of Sr, and the presence amount of Sr—Fe oxides satisfies a specific conditional expression, (2) the distribution in the number of the shape factor SF-2 is in a specific range, (3) the BET specific surface area is 0.15 to 0.30 m/g, (4) the average particle diameter Dis 20 to 35 μm, and (5) the magnetization is 50 to 65 Am/kg.