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US 4,595,937 AGranted
Ink jet print head
AssigneeIng. C. Olivetti & C., S.p.A.
InventorsRenatol Conta, Enrico Manini
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AssigneeIng. C. Olivetti & C., S.p.A.
InventorsRenatol Conta, Enrico Manini
Estimating the term…
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. The dielectric layer may be a first layer covered by a second layer with a hole in the first layer which is larger in diameter than the nozzle, thereby to create a reserve of ink for the frequent dots. For a multi-nozzle head, the nozzles are produced by grooving a portion of the container and then closing over the grooves by an insulating plate bearing the electrodes and the counterelectrodes which are spaced along the axes of the nozzles.
An ink jet print head comprising a container (14) for an electrically conductive ink (16) in contact with an electrode (34), wherein the container (14) is closed by a plate (17) comprising a base portion (31) of ceramic material and a metal layer (54) which is less than 50.mu. in thickness, and wherein the plate is provided with a capillary nozzle (18) formed by a hole which passes through the base portion and the metal layer, which acts as a counterelectrode (46;
An ink jet print head comprising a container (70) for an electrically conductive ink (16) in contact with electrode means (78), the container being provided with a series of mutually parallel capillary nozzles (72) at the outside end of each of which a meniscus (85) of the ink is formed, and counterelectrode means (79) spaced from the said electrode along the axis of the nozzle, the emission of the ink being caused by selectively energizing the electrode with respect to the counterelectrode with voltage pulses so as to cause vaporization of a portion of ink in the nozzle by the effect of the density of current through the ink in a section of the nozzle, wherein the container (71) comprises a closure plate (76) forming one side of the nozzle (72), the closure plate comprising a base portion of ceramic material carrying a metal layer which is etched to form a plurality of electrodes (78) and counterelectrodes (79) associated with the nozzles and axially aligned in the nozzles, so that each counterelectrode (79) is contacted by the ink in a portion set back into the nozle (18), whereby there is a predetermined thickness of ink (16) in the front part (86) of the nozzle between each meniscus (85) and the said section of each nozzle, whereby the vaporization of ink in this section causes the expulsion of at least part of the ink of the said thickness.
An ink jet print head comprising a container for an electrically conductive ink in contact with an electrode, the container being provided with a capillary nozzle at the outside end of which a meniscus of the ink is formed, and a counterelectrode spaced from the said electrode along the axis of the nozzle, the emission of the ink being caused by selectively energizing the electrode with respect to the counterelectrode with voltage pulses so as to cause vaporization of a portion of ink in the nozzle by the effect of the density of current through the ink in a section of the nozzle, characterized in that the counterelectrode is set back into the nozzle, whereby there is a predetermined thickness of ink in the front part of the nozzle between the meniscus and the said section of the nozzle, whereby the vaporization of ink in this section causes the expulsion of at least part of the ink of the said thickness, and comprising an auxiliary electrode (67) disposed on the outside surface thereof, the auxiliary electrode being capable of being energized by a voltage which is higher than the voltage of the pulses to remove encrustations of dry ink.
An ink jet print head comprising a container for an electrically conductive ink in contact with an electrode, the container being provided with a capillary nozzle at the outside end of which a meniscus of the ink is formed, and a counterelectrode spaced from the said electrode along the axis of the nozzle, the emission of the ink being caused by selectively energizing the electrode with respect to the counterelectrode with voltage pulses so as to cause vaporization of a portion of ink in the nozzle by the effect of the density of current through the ink in a section of the nozzle, characterized in that the counterelectrode is set back into the nozzle, whereby there is a predetermined thickness of ink in the front part of the nozzle between the meniscus and the said section of the nozzle, whereby the vaporization of ink in this section causes the expulsion of at least part of the ink of the said thickness, and characterized in that the container comprises an internal body having a concave surface spaced from the inward end of the nozzle by between 0.1 and 1 mm and which is capable of reflecting towards the nozzle the pressure wave which is caused by the vaporization effect.
An ink jet print head comprising a container (70) for an electrically conductive ink (16) in contact with an electrode (78), the container being provided with a capillary nozzle (72) at the outside end of which a meniscus (85) of the ink is formed, and a counterelectrode (79) spaced from the said electrode along the axis of the nozzle, the emission of the ink being caused by selectively energizing the electrode with respect to the counterelectrode with voltage pulses so as to cause vaporization of a portion of ink in the nozzle by the effect of the density of current through the ink in a section of the nozzle, characterized in that the counterelectrode (79) is contacted by the ink in a portion set back into the nozzle (18), whereby there is a predetermined thickness of ink (16) in front part (86) of the nozzle between the meniscus (85) and the said section of the nozzle, whereby the vaporization of ink in this section causes the expulsion of at least part of the ink of the said thickness.
Dependencies are inferred from the claim text.