Selective ink-jet printing device

摘要

The device comprises a printing head (15) constituted by an insulating container (19) with a capillary nozzle (36). The electrically conductive ink is kept under circulation in the container via a feed tube (26, 23) and a return tube (27, 24) leading to a suction pump, in order to allow the formation of a convex meniscus at the exit aperture of the nozzle (36) and eliminate any vapor bubbles. A pulse generator creates a voltage of a predetermined value and duration between an electrode (37) external to the nozzle and an electrode (23) in contact with the ink, in order to create a state of excitation of the meniscus and partial vaporization of a layer of ink, such as to expel a plurality of ink particles. The head is mounted on a carriage movable transversely to the paper, which advances at each stroke reversal of the head.