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:
Oct. 02, 2018
Filed:
Mar. 22, 2016
Dowa Electronics Materials Co., Ltd., Tokyo, JP;
Dowa Ip Creation Co., Ltd., Okayama-shi, Okayama, JP;
Yuto Kamai, Okayama, JP;
Takeshi Kawauchi, Okayama, JP;
DOWA ELECTRONICS MATERIALS CO., LTD., Tokyo, JP;
DOWA IP CREATION CO., LTD., Okayama, JP;
Abstract
A carrier core material includes, a main component, a material represented by a composition formula MnMFeO(where M is selected from Mg, Ti, Cu, Zn and Ni, 0<X, 0≤Y, 0<X+Y<1), in which 0.1 to 1.0 mol % of at least one of Sr element and Ca element is contained as the total amount by conversion to SrO or CaO and in which the frequency of a grain whose length RSm is equal or more than 8.0 μm among grains appearing on the surface of particles of the carrier core material is equal to or less than 2.0 number percent. In this way, the degradation of a carrier caused by long-term use such as the separation of a coating resin is significantly reduced, stable charging performance is maintained and the cracking or chipping of the particles is reduced.