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:
Aug. 20, 1996
Filed:
Jul. 18, 1994
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A developer for developing an electrostatic image is constituted by an insulating magnetic toner, inorganic fine powder and a flowability-improving agent having a BET specific surface area of at least 30 m.sup.2 /g. The insulating magnetic toner has a weight-average particle size (t-D.sub.4) of 4-14 .mu.m, a number-average particle size (t-D.sub.1) of 1-10 .mu.m, and a ratio (t-D.sub.4)/(t-D.sub.1) of 1.01-2. The inorganic fine powder has a weight-average particle size (m-D.sub.4) of 0.6-5 .mu.m, a number-average particle size (m-D.sub.1) of 0.5-4 .mu.m, and a ratio (m-D.sub.4)/(m-D.sub.1) which is in the range of 1.0-2.4 and is equal to or larger than the ratio (t-D.sub.4)/(t-D.sub.1). The inorganic fine powder is contained in an amount which is 2-8 times that of the flowability-improving agent by weight. The developer is able to retain stable developing performances by effecting suppressing preferential consumption of a particular particle size fraction in a long term of successive copying.