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:
Apr. 25, 1989
Filed:
Sep. 12, 1988
Satoshi Yasuda, Matsudo, JP;
Mitsuru Uchida, Chofu, JP;
Seiichi Takagi, Yokohama, JP;
Yusuke Karami, Kamakura, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A magnetic dry developer, comprising negatively chargeable insulating magnetic toner particles containing, at least, a binder resin, a magnetic substance, and an organo-chromium or -zinc complex; cerium oxide particles containing CeO.sub.2 as a predominant component and having a volume average particle size of 1.0 to 4.0 microns, a heating loss of 0.5 wt. % or less on heating up to 100.degree. C. and a BET specific surface area of 15 m.sup.2 /g or less as measured by the nitrogen adsorption method; and hydrophobicity-imparted negatively chargeable silicon oxide particulates. The cerium oxide particles have a function of disintegrating particularly the hydrophobicity-imparted silicon oxide particulates and enhance the attachment thereof to the toner particles, whereby the developing characteristics including the magnetic triboelectric chargeability are stabilized from the initial stage of electrophotographic copying operation.