Description of Jetting Conditions Based on Dynamic Surface Tension Derived from Ink Drop Oscillation Behavior

Abstract

Surfactant, when added to water-based inks, alters the dynamic surface tension, depending on the surface age. The interval time is considered to be equivalent to the surface age. In this study, a test liquid composed of glycerin and propylene glycol with a surfactant was used to vary the interval time until a drop for observation was ejected after refresh pulses. The jetting condition, which is defined as the time from the start of jetting until satellites coalesce into a sphere, was observed to change. Meanwhile, surface tension was measured by observing the oscillations of ink droplets in flight, using satellite collisions with the main drop under double pulse driving. The results showed that the Ohnesorge number, calculated from the measured dynamic surface tension, can be related to changes in satellite coalescence time during jetting.