Impact on Droplet Placement on Paper by the Level of Droplet Flight Stability in a Continuous Ink Jet Printer

Abstract

This report presents a study of how the level of droplet flight stability influences the positioning of droplets on paper for a continuous ink jet printer based on the Hertz technique. The droplet flight stability was measured with the aid of an optical system that provides a measure of stability based on the standard deviation for time between droplets for a large number of droplet-to-droplet intervals. The accuracy of droplet positioning on paper was analyzed by identifying dots in a grabbed image of a print and measuring the distance between them. The study shows a strong connection between low stimulation voltage, low droplet flight stability, and low precision in droplet placement on paper. The droplet flight stability was measured at a distance of 7 mm from the nozzle. When the standard deviation for droplet-to-droplet distances in flight was below 15° of the 360° droplet formation period, the standard deviation for distances between dots on paper was below 10 μm. No errors concerning the amount of ink in a pixel were present at this level of stability, which was reached for stimulation voltages above 4 V peak-to-peak (Vpp).