US 7,008,745 B2 · Gel organosol including amphipathic copolymeric binder having selected molecular weight and liquid toners for electrophotographic applications

Abstract

The invention provides liquid toner compositions in which the polymeric binder is chemically grown in the form of copolymeric binder particles dispersed in a liquid carrier. The polymeric binder includes one amphipathic copolymer comprising one or more S material portions and one or more D material portions, wherein the S material portion of the copolymer has molecular weight and solubility properties selected to provide a three dimensional gel of controlled rigidity which can be reversibly reduced to a fluid state by application of energy. The toners as described herein surprisingly provide compositions that are particularly suitable for electrophotographic processes wherein the transfer of the image from the surface of a photoconductor to an intermediate transfer material or directly to a print medium is carried out without film formation on the photoconductor.

Claims16

Dependent claims

A liquid electrophotographic toner composition comprising:

a) a liquid carrier having a Kauri-butanol number less than 30 mL;
and
b) a plurality of toner particles dispersed in the liquid carrier, wherein the toner particles comprise polymeric binder comprising at least one amphipathic copolymer comprising one or more S material portions and one or more D material portions, wherein the S material portions and the D material portions have respctive solubilities in the liquid carrier that are sufficiently different from each other such that the S material portions tend to be more solvated by the liquid carrier while the D material portions tend to be more dispersed in the liquid carrier, and wherein the S material portion of the copolymer has molecular weight and solubility properties selected to provide a three dimensional gel of controlled rigidity which can be reversibly reduced to a fluid state by application of energy;
and wherein the electrophotographic toner composition does not form a film under Photoreceptor Image Formation conditions.

1 more element

A method of making a liquid electrophotographic toner composition, comprising the steps of:

a) providing a plurality of free radically polymerizable monomers, wherein at least one of the monomers comprises a first reactive functionality;
b) free radically polymerizing the monomers in a solvent to form a first reactive functional polymer having a predetermined molecular weight and solubility parameter, wherein the monomers and the hydroxyl functional polymer are soluble in the solvent;
c) reacting a compound having a second reactive functionality that is reactive with the first reactive functionality and free radically polymerizable functionality with the first reactive functional polymer under conditions such that at least a portion of the second reactive functionality of the compound reacts with at least a portion of the first reactive functionality of the polymer to form one or more linkages by which the compound is linked to the polymer, thereby providing an S material portion polymer with pendant free radically polymerizable functionality;
d) copolymerizing ingredients comprising (i) the S material portion polymer with pendant free radically polymerizable functionality, (ii) one or more free radically polymerizable monomers, and (iii) a liquid carrier in which polymeric material derived from ingredients comprising the one or more additional monomers of ingredient (ii) is insoluble;
said copolymerizing occurring under conditions effective to form an amphipathic copolymer having S and D portions, wherein the S material portions and the D material portions have respctive solubilities in the liquid carrier that are sufficiently different from each other such that the S material portions tend to be more solvated by the liquid carrier while the D material portions tend to be more dispersed in the liquid carrier;
wherein the S material portions have molecular weight and solubility properties selected to provide a three dimensional gel of controlled rigidity which can be reversibly reduced to a fluid state by application of energy;
and wherein the electrophotographic toner composition does not form a film under Photoreceptor Image Formation conditions.

4 more elements

Dependencies are inferred from the claim text.

Gel organosol including amphipathic copolymeric binder having selected molecular weight and liquid toners for electrophotographic applications

Life of this patent

Gel organosol including amphipathic copolymeric binder having selected molecular weight and liquid toners for electrophotographic applications

Life of this patent

Abstract

Claims16