Abstract: Depoling and aging of a piezoelectric transducers used at elevated temperatures is controlled by poling the transducer, applying a bias voltage in the same direction as the transducer is poled to maintain the piezoelectric transducer at an elevated potential, and applying a drive voltage having a lesser magnitude than the bias voltage to induce elastic strain in the transducer.

Abstract: The operation of UU type drop-on-demand ink jet printheads are enhanced by selectively incorporating therein volume modifying tapers in the ink carrying channels, means for electrically isolating portions of the actuators thereof, and/or forming a variable layer of conductive material between the upper and lower sidewall portions therefore.

Abstract: A spot size modulatable, drop-on-demand type ink jet printhead and associated methods for ejecting volume modulatable droplets of ink therefrom. The ink jet printhead includes a main body portion having first and second ink carrying channels longitudinally extending therethrough and a cover plate fixedly mounted thereto. Formed in the cover plate is a tapered orifice which extends from first and second openings along a back side surface to a third opening along a front side surface thereof. The cover plate is mounted to the main body portion such that the first opening is in communication with the first ink carrying channel and the second opening is in communication with the second ink carrying channel. The ink jet printhead further includes first and second actuators coupled with the first and second ink carrying channels, respectively.

Abstract: Method for manufacturing a sidewall actuatable, high density channel array for an ink jet printhead. A first surface of a main body portion formed from an inactive material is conductively bonded to a first surface of a first intermediate body portion formed from an active material. A plurality of parallel grooves are then machined through the first intermediate body portion and part of the main body portion to form a plurality of channels separated by a corresponding plurality of sidewall actuators comprised of a first sidewall section formed from an inactive material and a second sidewall section formed from an active material. A top body portion is then conductively mounted to the intermediate body portion.

Abstract: A digital driver for an ink jet printhead and an associated method for selectively applying voltage to a piezoelectric sidewall actuator of the ink jet printhead. The digital driver includes positive and negative voltage sources, a first switching element having a first control input, a first voltage supply input connected to the positive voltage source, and a first output, and a second switching element having a second control input, a second voltage supply input connected to the negative voltage source, and a second output connected to the first output to provide a single output connected to the piezoelectric sidewall actuator. By asserting the first control input for a first time period, the first switching element generates a positive voltage pulse at the single output to displace the sidewall actuator from a rest position to a first position.

Abstract: An ink jet printhead and an associated method for operatively driving the ink jet printhead to cause the ejection of a volume modulatable droplet from an ink-carrying channel thereof partially defined by a piezoelectric sidewall actuator. The voltage applied across the sidewall actuator is raised from a rest voltage to a first voltage to deflect the sidewall actuator from a rest position to a first position and maintained at the first voltage for a first period of time. The voltage applied across the sidewall actuator is then dropped to a second voltage, lower than the rest voltage, to deflect the sidewall actuator from the first position, past the rest position, to a second position and maintained at the second voltage for a second period of time. The voltage applied across the sidewall actuator is then returned to the rest voltage to deflect the sidewall actuator back to the rest position.

Abstract: A switched digital drive system is used to actuate an ink jet printhead having a spaced, parallel series of internal ink receiving channels opening outwardly at front ends thereof through ink discharge orifices formed in the printhead body. The channels are laterally bounded by a spaced series of piezoelectrically deflectable internal sidewall sections of the printhead body interdigitated with the channels. The drive system includes a series of electrical actuation leads each connected to a different one of the sidewall sections, and dual transistor switch structures connected in the leads with each switch, in turn, connected to positive and negative DC voltage sources.

Abstract: Method for manufacturing a sidewall actuatable, high density channel array for an ink jet printhead. A first surface of a main body portion formed from an active material is conductively bonded to a first surface of a first intermediate body portion formed from an active material. A plurality of parallel grooves are then machined through the first intermediate body portion and part of the main body portion to form a plurality of channels separated by a corresponding plurality of sidewall actuators comprised of a first sidewall section formed from an active material and a second sidewall section formed from an active material. A top body portion is then conductively mounted to the intermediate body portion.

Abstract: Microdroplets of liquids at elevated temperatures are formed by transferring the liquid to an electrostrictive ejection device and applying an electric field which induces a second order elastic strain in the ejection device. The ejection device responds by ejecting generally spherically-shaped microdroplets. The ejection device comprises an electrostrictive transducer having an orifice through which the liquid is ejected. Drive electronics apply an excitation electric field to the electrostrictive transducer which causes a second order elastic strain in the electrostrictive transducer independent of the polarity of the electric field.

Abstract: The operation of U type drop-on-demand ink jet printheads are enhanced by selectively incorporating therein volume modifying tapers in the ink carrying channels, means for electrically isolating portions of the actuators thereof, and/or forming a variable layer of conductive material between the upper and lower sidewall portions therefore.

Abstract: An integrated multi-color drop-on-demand type ink jet printhead. The printhead includes a main body portion and a plurality of generally parallel, longitudinally extending ink-carrying channels arranged into at least two channel arrays. A manifold corresponding to each of the at least two channel arrays and in communication with each of the ink-carrying channels of the corresponding array is formed in the main body portion. Ink is supplied to each of the at least two channel arrays from a corresponding ink source, each of which is filled with a different color of ink.

Abstract: An ink jet printhead includes of a lower body part having a base section and a plurality of generally parallel spaced projections extending upwardly therefrom and an upper body part having a top section and a corresponding plurality of generally parallel spaced projections extending downwardly therefrom. The top sides of the lower body projections are conductively mounted to the bottom sides of the upper body projections to form sidewalls which define a plurality of ink-carrying channels. Strips of a conductive adhesive mount the lower and upper body projections together and a controller is electrically connected to the strips to selectively impart either a positive, zero, or negative voltage to each strip. The lower body part is formed using a piezoelectric material poled in a first direction generally perpendicular to the channels and the upper body part is formed using a piezoelectric material also poled in the first direction.

Abstract: A length mode drop on demand type ink jet print head includes a lower body portion formed of an active piezoelectric material and an upper body formed from an inactive material. The lower body portion, which includes a plurality of longitudinally extending projections, is poled in a first direction generally orthogonal to both its longitudinal and vertical axes. The upper body portion also includes a plurality of longitudinally extending projections. The lower and upper body portions are mated such that the lower and upper body projections are spaced interdigitally with each other. By mating the lower and upper body portions in this manner, a plurality of ink-carrying channels are formed. The ink jet print head further includes a controller for selectively applying an electric field across each of the lower body projections in the poling direction.

Abstract: An ink jet printhead for a drop-on-demand type ink jet printing system. The printhead includes a base section having a series of generally parallel spaced projections extending longitudinally therealong, a series of intermediate sections conductively mounted on a top side of a corresponding one of the series of base section projections and a top section conductively mounted to a top side of each of the series of intermediate sections.

Abstract: A method and apparatus for producing solidified solder balls and for ejecting generally spherical-shaped drops of liquid solder through a controlled atmosphere to impact on a surface to be wetted is disclosed. The apparatus comprises a preload reservoir to hold and maintain solder in a liquid state, an ejection chamber to hold and maintain the solder in a liquid state, a connection between the preload reservoir and the ejection chamber to allow liquid solder in the preload reservoir to be transferred to the ejection chamber while maintaining the oxides in the preload reservoir, a device to pressurize the ejection chamber with an inert gas and an ejection device operatively connected to receive liquid solder from the ejection chamber and to eject generally spherical-shaped drops of liquid solder to a specific location on a surface to be wetted. Structure is included to provide an atmosphere of inert gas between the ejection device and the specific location on a surface to be wetted.

Abstract: A sidewall actuated channel array for a high density ink jet printhead. The sidewall actuator includes a top wall, a bottom wall and at least one elongated liquid confining channel defined by the top wall, the bottom wall and sidewalls. The actuator sidewall is comprised of a first actuator sidewall section formed of a piezoelectric material poled in a first direction perpendicular to a first channel and attached to the top wall, a second actuator sidewall section attached to the first sidewall section and the bottom wall, and means for applying an electric field across the first actuator sidewall section and perpendicular to the direction of polarization. When the electric field is applied across the first sidewall section, the actuator sidewall engages in a motion which produces an ink ejecting pressure pulse in the channel.

Abstract: This invention relates to a system for printing and dispensing chemical reagents in precisely controlled volumes onto a medium at a precisely controlled location. A jetting tube, comprising an orifice at one end and a fluid receiving aperture at the other end, is concentrically mounted within a cylindrical piezo-electric transducer. The fluid receiving aperture is connected to a reservoir containing a selected reagent by means of a filter. The reservoir may be pressurized by a regulated air supply. An electrical signal of short duration is applied to the transducer. The pulse causes the transducer and the volume defined by the jetting tube to expand, thereby drawing in a small quantity of reagent fluid. The cessation of the pulse causes the transducer and the volume of the jetting tube to de-expand, thereby causing at least a substantially uniformly sized droplet of reagent fluid to be propelled through the orifice.

Abstract: Methods and apparatus for dispensing a fluid with dispersed particles therein are disclosed which include a reservoir containing the fluid and dispersed particles. The fluid is agitated to maintain dispersion of the particles. The output of the reservoir is provided through a filter to a three-way valve and pressurized as required. The common port of the three-way valve is connected to a print module controlled by a programmable controller. Bypass flow is provided to increase the flow rate through the system. The system may be operated in either the demand mode or the continuous mode.

Abstract: An ink jet printer for depositing drops of ink at a plurality of print positions on a moving print receiving medium includes a print head producing at least one jet drop stream directed toward the medium and a charge electrode positioned adjacent the point of drop formation of the jet drop stream. A charging means repetitively applies a high guard drop potential to the charge electrode during formation of at least every second drop for charging of the drops to a guard charge level. During formation of the remainder of the drops, either one of a number of relatively low print potentials or a substantially larger catch potential is applied to the charge electrode. Drops formed during application of a print potential to the electrode may carry a charge of either electrical polarity due the drop-to-drop cross talk from previously formed guard drops.