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:
Jul. 26, 1994
Filed:
Sep. 28, 1992
Bijay S Saha, Rochester, NY (US);
James H Anderson, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
A method of manufacturing improved strontium or barium ferrite carrier particles for use in two-component electrographic developer compositions for the development of electrostatic charge patterns is provided in which the tendency toward early life dusting of the strontium or barium ferrites is reduced. Such strontium or barium ferrite carrier particles are obtained by (i) mixing unreacted particles of iron oxide and barium or strontium oxide or, alternatively, a salt of barium or strontium convertible to the corresponding oxide by heat upon subsequent firing in a mole ratio of iron oxide to the metal oxide or salt of exactly 5.95 to 6.0:1 with an organic binder and a polar solvent, preferably water, to form a slurry, (ii) spray drying the slurry to obtain green beads of substantially uniform particle size and substantially spherical shape, and (iii) firing the beads at a temperature of from 1150.degree. to 1175.degree. C. for 10 hours to form magnetic strontium or barium ferrite carrier particles of substantially uniform particle size and substantially spherical shape having a reduced tendency towards early life dusting.