The present invention relates to a device for delivering ink, more particularly to a print head for an ink jet printer, provided with a series of ink delivery nozzles which can be actuated selectively when printing a sheet of paper or the like. The present invention also relates to an ink jet printer provided with such a device.
One known device of this kind has a substantially triangular base plate, the apex of which is directed towards the sheet for printing, and the oblique sides of which are provided with a number of ink ducts covered by a foil and extending to near the bottom or head end of the base plate, where they extend in the form of ink tunnels through the base plate towards the head surface. There the nozzles of the ink tunnels are covered by a nozzle plate, possibly in the form of a foil, in which a hole is made for each ink passage. Piezo-electric elements are disposed at the location of the foil over the ducts on the oblique sides and can be actuated selectively in order to briefly press on the foil above a duct and thus create a pressure pulse in the ink there, so that a droplet is delivered from the associated nozzle.
U.S. Pat. No. 4,364,067 discloses a print head attachment having a substantially rectangular base plate, the top of which is provided with an ink inlet connected to an ink reservoir and terminating in an ink distribution chamber to which are connected a number of ducts formed in the two sides. These ducts converge with an arc in the plane of the associated side to a number of downwardly directed ink delivery nozzles provided in a nozzle plate disposed in the base plate head surface situated transversely of the sides. The ink delivery nozzles form a Y-shaped duct, the branches of which extend to ducts on the opposite sides of the base plate.
The ducts themselves are covered by a vibrating plate on which an electrode is mounted. Provided on the electrode, at the location of the pressure chambers, are piezo-electric elements, which are also provided with an electrode. Selective actuation of the piezo-electric elements causes the vibrating plate to be pressed in locally and the volume of the pressure chamber in the required duct is reduced so that a specific quantity of ink is propelled through said duct to the associated ink delivery nozzle.
A disadvantage of the known printer heads is that the ink-tight layers adjoin one another at an angle so that sealing may be locally inadequate.