Carrier particles bearing insoluble metal salt deposits
AssigneeEastman Kodak Company
InventorWilliam Edward Yoerger
Life of this patent
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Abstract
Carrier particles for use in negative electrostatographic developers wherein said particles bear, based on the weight of the carrier particles, from 0.1 to 2 weight percent of deposits selected from the group consisting of (a) strontium carbonate, (b) insoluble metal hydroxides, (c) an insoluble metal hydrated oxide, and (d) mixtures thereof; provided that when the said carrier particles bear a polymeric flurocarbon coating the deposit is other than strontium carbonate.
Claims14
Carrier particles for use in negative electrostatographic developers wherein said particles bear, based on the weight of the carrier particles, from 0.1 to 2 weight percent of deposits selected from the group consisting of (a) strontium carbonate, (b) insoluble metal hydroxides, (c) an insoluble metal hydrated oxide, and (d) mixtures thereof;
- provided that when the said carrier particles bear a polymeric flurocarbon coating the deposit is other than strontium carbonate.
A method of modifying the triboelectric charging propensity electrostatographic developer carrier particles, comprising the steps of:
- (A) providing a carrier particles that is uncoated or polymer coated;
- (B) mixing the carrier particles with an oxidizing agent and either (i) an aqueous basic solution or (ii) an aqueous solution containing from 0.1 to 5.0 weight percent of a soluble acidic metal salt, based on the weight of the carrier particles to form a mixture;
- and
- (C) contacting the mixture with the solution, (i) or (ii), not used in step (B) thereby causing a precipitate of an insoluble salt to deposit on the carrier particles wherein the insoluble salt is
- (a) strontium carbonate;
- (b) insoluble metal hydroxides;
- (c) insoluble metal hydrated oxides;
- or
- (d) a mixture of two or more of (a), (b) and (c).
A negative electrostatographic developer composition comprising toners and carrier particles bearing deposits selected from the group consisting of (a) strontium carbonate, (b) insoluble metal hydroxides, (c) insoluble metal hydrated oxides or (d) mixtures thereof;
- provided that when the said carrier particles bear a polymeric flurocarbon coating the deposit is other than strontium carbonate.
Dependencies are inferred from the claim text.