PIGMENT-BASED INKJET INKS

摘要

An inkjet ink composition comprising: (a) water; (b) dispersed pigment particles; and (c) at least one humectant; wherein the pigment particles are present from about 4.5% by mass to about 10% by mass, and the pigment particles have a mass weighted mean Stoke's diameter of from about 35 nm to about 70 nm wherein the Stoke's diameter is determined by differential centrifugal sedimentation of the particles through a fluid in a disc centrifuge. The present invention employs specified sedimentation particle sizing criteria for selection of appropriate pigment particle sizes at high pigment concentrations to obtain improved ink performance. Further embodiments of the invention also demonstrate that the criticality of humectant types and levels employed in an ink can also become much more important at high pigment loading in order to obtain desired performance.