Abstract: A droplet emitter with an array of droplet emitting devices constructed such that one flowing liquid is used to create the droplets while a second low acoustic impedance liquid can be used to both make the transfer of acoustic energy to the first liquid more efficient and help maintain a uniform temperature of the droplet emitter array. Both liquids can be circulated through the droplet emitter to allow for excess heat generated by control electronics to be transferred to the flowing liquids. This prevents, for instance excess heat build-up within the droplet emitter and allows for higher more accurate droplet emission rates.

Abstract: A droplet emitter with an array of droplet emitting devices constructed such that one flowing liquid is used to create the droplets while a second low acoustic impedance liquid can be used to both make the transfer of acoustic energy to the first liquid more efficient and help maintain a uniform temperature of the droplet emitter array. Both the emission fluid and the low acoustic impedance fluid can be circulated through the droplet emitter to allow for excess heat generated by control electronics to be transferred to the flowing. This prevents for instance excess heat build up within the droplet emitter and allows for higher more accurate droplet emission.

Abstract: A drop-on-demand ink jet print head (9) has an ink pressure chamber (22) coupled to a source of ink (11) and an ink drop ejecting orifice (103) with an ink drop ejection orifice outlet (14). An acoustic driver (36), in response to a drive signal (100), produces a pressure wave in the ink and causes the ink to pass outwardly through the ink drop ejecting orifice (103) and the ink jet ejection orifice outlet (14) of the ink jet print head (9). In accordance with the present invention, controlling the operation of the ink jet print head (9) with a particular drive signal reduces print quality degradation resulting from rectified diffusion, which is the growth of .air bubbles dissolved in the ink from the repeated application of pressure pulses to the ink residing within the ink pressure chamber (22) of the ink jet print head (9), such pressure pulses causing the application of pressures below ambient pressure.

Abstract: A drop-on-demand ink jet has an ink chamber coupled to a source of ink, and an ink drop orifice with an outlet. An acoustic driver produces a pressure wave in the ink and causes the ink to pass outwardly through the ink drop orifice and outlet. The driver is driven with bipolar drive pulses having a refill pulse component and an eject pulse component of a polarity which is opposite to the refull pulse component. The refill and eject pulse components are separated by a wait period. The drive pulses may be adjusted to minimize their energy content at a frequency corresponding to the dominant acoustic resonance frequency of the ink jet. This will accelerate drop breakoff, optimize drop shape and minimize drop speed variations over the range of drop printing rates. The ink jet printer of the present invention may be used to print with a wide variety of inks, including phase change inks to achieve high print quality at high print rates.

Abstract: A drop-on-demand ink jet print head (9) has an ink pressure chamber (22) coupled to a source of ink (11) and an ink drop ejecting orifice (103) with an ink drop ejection orifice outlet (14). An acoustic driver (36), in response to a driver signal (100), produces a pressure wave in the ink and causes the ink to pass outwardly through the ink drop ejecting orifice (103) and the ink jet ejection orifice outlet (14) of the ink jet print head (9). In accordance with the present invention, controlling the operation of the ink jet print head (9) with a particular drive signal reduces print quality degradation resulting from rectified diffusion, which is the growth of air bubbles dissolved in the ink from the repeated application of pressure pulses to the ink residing within the ink pressure chamber (22) of the ink jet print head (9), such pressure pulses causing the application of pressures below ambient pressure.

Abstract: A drop-on-demand ink jet has an ink chamber coupled to a source of ink, and an ink drop orifice with an outlet. An acoustic driver produces a pressure wave in the ink and causes the ink to pass outwardly through the ink drop orifice and outlet. The size of the ink drops may be varied, such as by driving the acoustic driver with varying drive signals, preferably comprising individual or combinations of plural bipolar drive pulses. The ink jet printer of the present invention may be used to print with a wide variety of inks, including phase change inks.

Abstract: An extremely compact ink jet print head has an array of closely spaced nozzles which are supplied from densely packed ink pressure chambers by way of offset channels. The ink supply inlets leading to the pressure chambers and the offset channels are designed to provide uniform operating characteristics to the ink jet nozzles of the array. To enhance the packing density of the pressure chambers, the ink supply channels leading to the pressure chambers and offset channels are positioned in planes between the pressure chambers and nozzles. An optional ink purging pathway is provided for purging bubbles and other contaminants from the chamber side of the nozzles. The ink jet print head may be assembled from plural plates with features in all but the nozzle defining plate being formed by photo-patterning and etching processes without requiring machining or other metal working.

Abstract: A first surface of a first metal component of an ink jet print head is bonded to a second surface of a second metal component of the ink jet print head, the first and second surfaces being of materials having the same or similar coefficients of thermal expansion. A layer of filler material is electroplated or otherwise placed on at least one of these surfaces. The filler material has a melting point which is below the melting point of the first and second components, and the total thickness of the filler material on the surfaces together is in the range of from approximately one-sixteenth micron to approximately five microns, with one-eighth micron to two microns being a preferred range. These surfaces are placed together and subjected to heat and pressure to diffusion bond the surfaces without melting the filler material. The diffusion bonding is performed in one approach until no more than approximately one micron of filler material remains between the surfaces.

Abstract: An air-assisted drop-on-demand ink jet head 10 has a single compartment ink chamber 14 and is designed for operation over a wide range of ink drop repetition rates, including extremely high repetition rates, such as twenty kilohertz. The components included in the ink jet head have natural resonance frequencies which are greater than the desired maximum drop generation frequency of the ink jet head. In addition, the natural frequency of each of the components of the ink jet head are sufficiently different from one another to prevent intercoupling. Ink is supplied to the ink chamber 14 via a supply inlet passageway 38 which has a cross-sectional area which is sized large enough to allow the supply of ink to the ink chamber. Yet, this area is small enough so that the natural frequencies of ink in the ink inlet do not significantly alter drop generating pressure pulses in the ink chamber 14.