Patent ID: 7655708

Claim:
An ink composition comprising an aqueous media and a pigment dispersion comprising (a) a carbon black pigment having a DBP oil absorption of at least 70 ml/100 gram, and a median effective dispersion particle size of between 55 nm and 200 nm; and (b) a polymeric dispersant wherein said polymeric dispersant is a copolymer comprising: a) at least a hydrophobic methacrylate or acrylate monomer containing an aliphatic chain having greater than or equal to 12 carbons; b) a hydrophobic benzyl methacrylate or benzyl acrylate monomer; and c) a hydrophilic methacrylic or acrylic acid monomer; wherein said copolymer comprises greater than 20% by weight of the methacrylate or acrylate monomer containing an aliphatic chain having greater than or equal to 12 carbons and at least 15% by weight of the methacrylic or acrylic acid monomer, and the copolymer has a weight average molecular weight of less than 15,000 daltons.