Abstract: The head is provided for a conductive ink in contact with an electrode (34) and comprises a container (14) having a capillary nozzle (18, 53) and a counterelectrode (54) set into the nozzle that predetermined thickness of ink is in the front part (53) of the nozzle between the meniscus (52) and the inner part of the nozzle wherein a vaporizing current flows between the electrode and the counterelectrode, thereby to expel the said thickness of ink. For that purpose, the container is closed by an insulating plate (30, 31) on which the counterelectrode (54) is disposed, the counterelectrode in turn being covered by a dielectric layer (56). The nozzle is formed by means of a single hole through the plate, the counterelectrode may be of the same thickness as the said thickness of ink, so that the front part of the nozzle is all through the counterelectrode.

Abstract: The head is provided for a conductive ink (16) and comprises a container (14) having a capillary nozzle (18) where the ink is in contact with a pair of electrodes facing each other across the nozzle, in such a way as to be covered by a predetermined depth of ink between the electrodes and the meniscus (52) at the front end of the nozzle. Printing is effected by vaporization of a portion of ink in a section of the nozzle between the electrodes, which expels the said depth of ink. The container is closed by an insulating plate (30) over which extends a metal strip (37) of smaller width than the diameter of the nozzle. The nozzle is formed by means of a single hole through the plate and the strip, whereby the strip is separated into two electrodes. The metal strip may be disposed between the plate and a front dielectric layer 43.