Traveling wave ink jet printer with drop-on-demand droplets

摘要

A traveling wave droplet generator having a drop-on-demand mode of operation. An acoustic mechanism excites a line of peaks of ink just below threshold for ink drop ejection in the orifices of an ink chamber. Electrostatic means raises particular peaks above the threshold using an excitation that is synchronous with the acoustic wave, which gives rise to parametric coupling which enhances the efficiency of the ejection. The electrostatic field can be selectively established at each of the orifices by a conventional addressing mechanism.