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. 12, 2004
Filed:
Sep. 11, 2002
Yuichi Mizoo, Ibaraki, JP;
Tadashi Dojo, Shizuoka, JP;
Nene Shibayama, Shizuoka, JP;
Yusuke Hasegawa, Ibaraki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A magnetic black toner comprising magnetic black toner particles containing at least a binder resin and a magnetic material. The toner has a weight-average particle diameter of from 5 &mgr;m to 12 &mgr;m, and the toner has, in its particles of 3 &mgr;m or more in diameter, at least 90% by number of particles with a circularity of 0.900 or more and has an average circularity of from 0.940 to 0.970. The magnetic material comprises iron oxide particles which have an average particle diameter of from 0.10 &mgr;m to 0.30 &mgr;m, contain titanium or a titanium compound in an amount of from 0.3% by weight to 1.5% by weight in terms of titanium, based on the total weight of the iron oxide particles, and have the ratio of the proportion of FeO to the total Fe content in 10% by weight from the particle surface, A %, to the proportion of FeO to the total Fe content in the remainder 90% by weight, B %, which satisfies the expression: 0.7≦A/B≦1.0. Also, an inorganic fine powder is externally added to the toner particle surfaces.