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:
May. 18, 1993
Filed:
Jun. 06, 1991
Koichi Tsuyama, Kobe, JP;
Hiroshi Harada, Nikaho, JP;
Mita Industrial Co., Ltd., Osaka, JP;
TDK Corporation, Tokyo, JP;
Abstract
Magnetic carrier for use in electrophotographic development takes the form of ferrite core particles each having a resinous coating. Ferrite core particles having a limited particle size distribution are coated with a resinous composition based on a copolymer consisting essentially of ethyl methacrylate, 15 to 25% by weight of styrene, up to 2% by weight of dodecyl methacrylate, and up to 2% by weight of 2-hydroxyethyl acrylate. The magnetic carrier particles have a resistance of 8.5.times.10.sup.7 to 2.2.times.10.sup.9 .OMEGA.. This carrier has a sharp distribution of electric charge and a quick rise of charging performance. The coating is tough enough to impart durability to the carrier.