Inkjet ink comprising dynamic surface tension agent

摘要

An inkjet ink comprising water, colorant, and a dynamic surface active agent at an effective concentration such that dynamic surface tension DST20 min at 20 minutes universal surface age is less than each of dynamic surface tension DST1 sec at 1 second universal surface age and dynamic surface tension DST10 sec at 10 seconds universal surface age, and the difference between DST10 sec and DST20 min is greater than 9.2 mN/m at 21° C. or the difference between DST1 sec and DST20 min is greater than 15.5 mN/m at 21° C., and static surface tension of the ink is less than 50 mN/m. Large dynamic surface tension differences between the indicated time scales yield an optical density improvement in printed images. Anionic fluorosurfactant comprising a phosphate group at concentrations up to about 1 weight percent enables a combination of high optical density and good felt wetting in inkjet cartridges.

主权项

1. An inkjet ink comprising water, colorant, and a dynamic surface tension agent at an effective concentration such that the ink has a dynamic surface tension DST1 sec at 1 second universal surface age, a dynamic surface tension DST10 sec at 10 seconds universal surface age and a dynamic surface tension DST20 min at 20 minutes universal surface age, where DST20 min is less than each of DST1 sec and DST10 sec, and the difference between DST10 sec and DST20 min is greater than 9.2 mN/m at 21° C. or the difference between DST1 sec and DST20 min is greater than 15.5 mN/m at 21° C., and wherein the static surface tension of the ink is less than 50 mN/m, further wherein the dynamic surface tension agent is an anionic fluorosurfactant comprising a phosphate group.