Patent ID: 6946023

Claim:
A smear-resistant ink composition comprising: (a) water; (b) at least one glycol selected from the group consisting of diethylene glycol, ethylene glycol, glycerol, and propylene glycol; (c) a pyrrolidone selected from the group consisting of 2-pyrrolidone and 3-pyrrolidone; and at least one colorant to yield a detectable fluorescent color when the ink composition is applied to paper, a biocide; a nonionic surfactant; optionally, a basic color stabilizer selected from a group consisting of ethanolamine, diethanolamine, and triethanolamine; optionally, a resin that is styrenated acrylic polymer; and optionally, a resin modifier that is selected from potassium carbonate and sodium carbonate, wherein the ink is a fluid.