Method and device for applying a plurality of microdroplets onto a substrate

A device for applying a plurality of microdroplets onto a substrate, comprising:

• a plurality of nozzle orifices in a first surface of a dosing head;
• walls for defining a liquid column of a medium to be dosed on each nozzle orifice;
• a pressure chamber which is adapted to be filled with a buffer medium and which is arranged in such a way that said buffer medium can simultaneously be used for applying a pressure to ends of the liquid-columns, which are spaced apart from the nozzle orifices;
• a pressure generator for applying a pressure to said buffer medium which in turn applies pressure to the ends of the liquid columns causing simultaneous ejection of microdroplets through the nozzle of orifices onto the substrate;
• and
• liquid reservoirs for the media to be dosed, which are in fluid communication with the liquid columns on the nozzle orifices and comprise reservoir openings in a second surface of said dosing head opposite to said first surface,
• wherein the reservoir openings are outside of and spaced from the pressure chamber.