The GeSiM microdispensers dont touch the surface to spot on, which minimizes damage to the surface and maximizes spotting flexibility. The dispensers (also called "pipettes" or "jets") follow the drop-on-demand principle, i.e., a drop is released exactly when the piezo ceramic actuator is triggered. This results in the bending of a silicon diaphragm behind the actuator and this in turn leads to a compression of the liquid inside the pump chamber and hence to the ejection of a droplet from the nozzle. After this, the ceramic returns to its initial state and the dispenser is refilled with liquid from the inlet. No valve is involved in this process.