Patent ID: 7204872

Claim:
A pigment-free ink-jet ink, comprising: (a) an aqueous liquid vehicle including 1-(2-hydroxyethyl)-2-pyrrolidinone and an aliphatic polyhydric alcohol co-solvent; (b) a colorant consisting essentially of a dye that is solubilized in the aqueous liquid vehicle, wherein the colorant is a metallized dye or a plurality of dyes; and (c) from 0.5 wt % to 8 wt % of an inorganic or organic salt selected from the group consisting of Mg 2+ (NO 3 ) 2 2− , Li + NO 3 − , K + NO 3 − , Na + CH 3 SO 3 − , Mg 2+ SO 4 2− , Na + NO 3 − , Mg 2+ (CH 3 SO 3 ) 2 2− , and mixtures thereof.