Drop quality control system for jet printing

摘要

A method and apparatus are disclosed for controlling the flight time and composition of a marking fluid used in a continuous jet marking system. A three-way valve permits switching between fresh ink and system ink supplies. Periodically a comparison of pressure required to maintain a constant drop flight time is made by a controller. Because both supplies are in the same operating environment any difference in pressure is due to a change in system ink viscosity. Solvent is added, if necessary, to the system ink via a pump to restore viscosity to desired values.