Patent ID: 7803851

Claim:
An inkjet ink comprising: a pigment dispersion containing an organic dispersion medium, a black pigment having a z-average particle diameter of not more than 200 nm, first resinous dispersing agent and second resinous dispersing agent different from the first resinous dispersing agent, the organic dispersion medium being at least one polymerizable compound, the black pigment being at an amount ranging from 2 to 30% by weight based on the organic dispersion medium, and an ionic compound; wherein a ζ-potential of the black pigment to the at least one polymerizable compound of the organic dispersion medium is confined within the range of −10 mV to +100 mV, the first and second resinous dispersing agents being adsorbed to the black pigment, the ζ-potential being determined by subjecting the inkjet ink to electrophoresis; and wherein the second resinous dispersing agent is a resinous polymer dispersing agent having a basic terminal, and amine value ranging from 5 to 200 mgKOH/g and a number average molecular weight ranging from 1,000 to 100,000 and is incorporated at an amount ranging from 2 to 60% by weight based on the pigment.