Bleed control in ink-jet inks via aqueous phase separation

Abstract

Aqueous phase separation is employed to reduce or substantially eliminate bleed between adjacently-printed ink-jet ink compositions. An ink-jet ink set is provided that comprises first and second ink-jet inks, both of which comprise a colorant and an aqueous vehicle. The vehicle of the first ink-jet ink includes a polymer, while the vehicle of the second ink-jet includes a second species capable of inducing aqueous phase separation between the first and second inks in the event of contact therebetween. The resulting aqueous phases are separated by an interfacial boundary that serves to inhibit bleed between the inks. Importantly, in spite of the polymer concentration contained therein, the inks in the ink-jet ink set have sufficiently low viscosities such that they are capable of being readily jetted from an ink-jet pen. The use of aqueous phase separation to achieve bleed control is advantageous because it offers more flexibility in ink formulation, does not introduce highly toxic or corrosive components to the ink-jet ink composition, does not sacrifice edge acuity, and is an easily implemented and cost-effective manner in which to achieve bleed control in ink-jet printing.

Dependencies are inferred from the claim text.