Patent ID: 7771523
Filing Date: 2010-08-10
Classification: C09D

Abstract:
1. An inkjet ink comprising an aqueous vehicle, a colorant, and a first and second cationic species wherein: i) said aqueous vehicle comprises water and a first humectant wherein said first humectant is any member or combination of members selected from the group consisting of 2-pyrrolidone, di-(2-hydroxyethyl)-5,5-dimethyl hydantoin, sulfolane, tetramethylene sulfoxide, 1,3-dimethyl-2-imidazolidinone and imidazolidinone; ii) said colorant comprises self-dispersed pigment with anionic carboxylate dispersibility-imparting surface groups; iii) said first cationic species is Li iv) said second cationic species is any member or combination of members selected from the group consisting of Na v) the molar ratio of M1 to Mtot, satisfies Equation 1 as follows: wherein Mtot is the cumulative molar concentration of first and second cationic species per unit weight of ink (Mtot=M1+M2).