The first test was printing a vector graphic with Estlcam. 

In this test I started the piezo, printed the line and turned off the piezo.

In the next tests I tried printing dot matrices with Pixels to Gcode by Matthew Rayfield on 80g/m² paper.

It seems that 80g/m² paper is too thin for the drop size, so I switched to 120g/m² paper.

I think, I will stay on the dot matrix methode, but try to improve the printing speed.