Abstract: A drop delivery printhead includes a well about a nozzle opening to enhance jetting performance.

Abstract: An apparatus for depositing droplets on a substrate is disclosed. The apparatus includes a support for the substrate, a droplet ejection assembly which includes a pumping chamber, a controller and a source of static pressure to maintain the total pressure in the pumping chamber above a threshold pressure level to avoid rectified diffusion type bubble growth in the pumping chamber. The droplet ejection assembly is positioned over the support for depositing the droplets on the substrate and includes, in addition to a pumping chamber, a displacement member and an orifice that ejects the droplets. The controller provides signals to the displacement member to eject drops.

Abstract: An apparatus for depositing droplets on a substrate is disclosed. The apparatus includes a support for the substrate, a droplet ejection assembly which includes a pumping chamber, a controller and a source of static pressure to maintain the total pressure in the pumping chamber above a threshold pressure level to avoid rectified diffusion type bubble growth in the pumping chamber. The droplet ejection assembly is positioned over the support for depositing the droplets on the substrate and includes, in addition to a pumping chamber, a displacement member and an orifice that ejects the droplets. The controller provides signals to the displacement member to eject drops.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon body is formed with ink passages, such as internal passages extending through a carbon plate, pressure chambers on one side of a carbon plate, flow-through passages on the other side of the same plate and ink supply passages, and a piezoelectric plate is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. The piezoelectric plate may have a conductive coating on one side which is photo-etched to produce an electrode pattern corresponding to the pattern of the pressure chambers in the carbon plate. An orifice plate may have specially profiled orifice openings to assure axial projection of drops and may be affixed by a thin layer of epoxy adhesive to a carbon plate having orifice passages supplying ink from the pressure chambers to the orifices.

Abstract: Conditioning an ink jet orifice by illuminating the orifice with radiation to remove contaminants, smooth rough surfaces, and/or round sharp edges.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon body is formed with ink passages, such as internal passages extending through a carbon plate, pressure chambers on one side of a carbon plate, flowthrough passages on the other side of the same plate and ink supply passages, and a piezoelectric plate is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. In one alternative embodiment, an ink jet head assembly contains two separate carbon pressure chamber plates, a carbon manifold plate and a carbon collar to retain the carbon plates in an assembly.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon body is formed with ink passages, such as internal passages extending through a carbon plate, pressure chambers on one side of a carbon plate, flowthrough passages on the other side of the same plate and ink supply passages, and a piezoelectric plate is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. The piezoelectric plate may have a conductive coating on one side which is photoetched to produce an electrode pattern corresponding to the pattern of the pressure chambers in the carbon plate. An orifice plate may have specially profiled orifice openings to assure axial projection of drops and may be affixed by a thin layer of epoxy adhesive to a carbon plate having orifice passages supplying ink from the pressure chambers to the orifices.

Abstract: In the ink jet printing system described in the specification, a hot melt ink jet printhead having two ink reservoirs is coupled through an ink supply line to a remote hot melt ink supply and a temperature controller is arranged to control the temperatures of the ink in the remote ink supply, the supply line, the ink reservoirs in the printhead and passages leading from the reservoirs to the ink jet orifices at selected temperature levels to inhibit high-temperature degradation of the ink while permitting the ink to be jetted at the desired jetting temperature. In addition, a pressure control system controls the pressure of the ink in the printhead at one or more selected levels to permit the printhead to be used at different orientations and to permit purging of air bubbles and contaminants from the orifice passageways and to supply a relatively high vacuum to a deaerator in the printhead to extract dissolved air from the ink.

Abstract: In the simplified ink jet head described in the specification, a tubular member made of air-permeable, ink-permeable material which is closed at one end and connected at the other end to a source of subatmospheric pressure is inserted into an ink passage in the ink jet head to extract dissolved air through the material of the tubular member from a surrounding body of ink in the ink passage.

Abstract: In the embodiments of the simplified ink jet head described in the specification an orifice plate has specially profiled orifice openings to assure axial projection of drops when ink is supplied from an asymmetric ink path leading to the orifice. For this purpose the orifice includes cylindrical ink inlet and outlet portions with the ink outlet portion having a smaller diameter and a shorter length than the inlet portion and a tapered conical portion joining the ink inlet portion and the ink outlet portion. Preferably, the diameter of the inlet portion is no more than about twice the diameter of the outlet portion.

Abstract: In the embodiments described in the specification, a ceramic piezoelectric plate is polarized by compressing the plate between electrode plates with intervening slightly conductive rubber sheets or by applying electric charge from a corona discharge device to one surface of the plate while the opposite surface is grounded until the applied charge is sufficient to create a breakdown.

Abstract: In the ink jet printing system described in the specification, a hot melt ink jet printhead having two ink reservoirs is coupled through an ink supply line to a remote hot melt ink supply and a temperature controller is arranged to control the temperatures of the ink in the remote ink supply, the supply line, the ink reservoirs in the printhead and passages leading from the reservoirs to the ink jet orifices at selected temperature levels to inhibit high-temperature degradation of the ink while permitting the ink to be jetted at the desired jetting temperature. In addition, a pressure control system controls the pressure of the ink in the printhead at one or more selected levels to permit the printhead to be used at different orientations and to permit purging of air bubbles and contaminants from the orifice passageways and to supply a relatively high vacuum to a deaerator in the printhead to extract dissolved air from the ink.

Abstract: In the embodiment of the cleaning device described in the specification, a web of paper is movable past the orifice plate of an ink jet head from a supply roll to a take-up roll. The cleaning device has a movable front end portion with two pressure bars positioned to urge the web of paper against two portions of the orifice plate, one portion being in line with the orifices and the other below the orifices. The pressure bar supports are arranged so that the bar positioned in line with the orifices engages the web after the other bar has urged the web against the orifice plate. The cleaning device also collects ink ejected during purging of air from the system and may be positioned to prevent ejection of ink during an internal purging operation.