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:
Nov. 28, 1989
Filed:
Jan. 25, 1988
Masao Watanabe, Tokyo, JP;
Hiroshi Nagase, Tokyo, JP;
Fujikura Kasei Co., Ltd., Tokyo, JP;
Abstract
A negatively chargeable toner for use in dry electrophotography, said toner comprising (A) a resinous binder composed of at least one resin selected from copolymers of styrene and/or alpha-methylstyrene with alkyl (meth)acrylates, (B) 2 to 10 parts by weight, per 100 parts by weight of the resinous binder, of a copolymer containing a sulfonic acid group, said copolymer having a weight average molecular weight of from 2,000 to 15,000 and composed of 80 to 98% by weight of recurring units represented by the formula ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group, and 20 to 2% by weight of recurring units represented by the formula ##STR2## and (C) a coloring agent.