Patent ID: 8784549

Claim:
An aqueous ink set for continuous inkjet printing comprising at least one cyan ink, at least one yellow ink, at least one magenta ink, and at least one black ink, wherein each ink of the ink set comprises dispersed pigment particles and the said cyan, yellow, magenta, and black pigment particles are dispersed with a polymeric dispersant, and at least one surfactant selected to provide a 10-ms dynamic surface tension of less than 54 mN/m for each ink, wherein each of the inks are comprised of less than 10 wt % of humectant and co-solvent and have a static surface tension of at least 35 mN/m, wherein the said cyan, yellow, magenta, and black inks each have a dynamic fluid viscosity of less than about 2.0 mPa-s, wherein at least one of the cyan, yellow, magenta, and black inks comprises a water soluble homopolymer or co-polymer additive distinct from any dispersant used to disperse the pigment particles, and wherein the polymer additive is present in an amount of from 0.05% to 5% by weight effective to stabilize the ink composition against particle aggregation caused by pumping the ink composition through a continuous ink jet printing fluid system.