Scratchbuilt Piezo Printhead
This is a description of a simple DIY Piezo print head.
or to be more precise early attempts.
The last time I looked at piezo materials they were to expensive for the tinkerer to play with, after some searching, bimorphs, or buzzers seemed like the only affordable source of piezo actuators, whilst they have a low frequency compared to normal ultrasonics at the audible range of around 2KH, this should be ample for pumping or jetting or spraying fluids.