Toners with improved pigment dispersion
AssigneeInternational Communications Materials, Inc.
InventorRichard J. Thompson
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Abstract
The invention relates to color toner compositions prepared from an aqueous pigment concentrate dispersion which renders a toner exhibiting improved pigment dispersion, and consequently improved image density and color characteristics.
Claims10
A process for preparing a toner composition comprising:
- a) blending an aqueous, liquid state, pigment concentrate dispersion with dry toner components including a binder resin, a charge control agent and a release agent, wherein the aqueous pigment concentrate contributes about 10 wt % to about 15 wt % water to the blend;
- b) compounding the blend from step (a) to produce a ribbon of molten toner;
- c) cooling and coarse crushing the toner ribbon;
- d) jet pulverizing the crushed toner to produce a toner powder with a mean particle size by volume of from about 5 μm to about 15 μm;
- and
- e) optionally blending the toner powder with one or more post additive agents,
- wherein the toner particles exhibit under microscopic examination at 600× magnification substantial uniformity of component content and are substantially free of pigment particle agglomerates and voids having no pigment.
An electrophotographic toner composition comprising homogeneous particles of toner, each particle possessing a uniform mixture of resin, colorant and additives, wherein the colorant is a pigment provided in the form of an aqueous pigment concentrate dispersion in the liquid state, having a pigment concentration of from about 40 wt % solids to about 40 wt % solids, and the remaining toner components are orovided in dry form.
Dependencies are inferred from the claim text.