Patent ID: 7220528

Claim:
An ink composition comprising: a vehicle, a first surfactant, a pigment colorant, and amphipathic polymer particles prepared by: i) admixing an aqueous carrier, an unsaturated monomer containing a hydrophobic moiety, an unsaturated monomer containing a convertible moiety in hydrophobic form, and a second surfactant to form an emulsion; ii) initiating a polymerization by adding a catalyst to the emulsion; iii) continuing polymerization at a temperature and for a period of time sufficient to form amphipathic polymer particles, wherein the amphipathic polymer particles have a size range of 50–500 nm; and iv) converting the convertible moiety of the amphipathic polymer particles from hydrophobic form to hydrophilic form by changing the pH of the emulsion, wherein said vehicle is water or a mixture of water and one or more humectants.