Abstract: In a ground penetrating radar system, A-scan images of subsurface targets lying along the antenna boresight axis can be substantially improved and generated in real-time by employing a synthetic aperture, end-fire array, despite the inhomogeneous nature of the subsurface volume. The synthetic aperture, end-fire array is achieved by generating electro-magnetic (EM) ultra-wideband impulses at a number of precise locations along the antenna boresight access, shifting the returned EM signals in the time domain according to the corresponding antenna boresight location, and then integrating the shifted, returned EM signals. In addition, an incremental, reverse-coherent integration technique is provided. This incremental technique allows for a more rapid generation of the A-scan image. The reverse-coherent integration technique eliminates unintended, stationary targets from the A-scan image, which are caused by coherent noise/clutter sources.

Abstract: In a ground penetrating radar system, A-scan images of subsurface targets lying along the antenna boresight axis can be substantially improved and generated in real-time by employing a synthetic aperture, end-fire array, despite the inhomogeneous nature of the subsurface volume. The synthetic aperture, end-fire array is achieved by generating electromagnetic (EM) ultra-wideband impulses at a number of precise locations along the antenna boresight access, shifting the returned EM signals in the time domain according to the corresponding antenna boresight location, and then integrating the shifted, returned EM signals.

Abstract: A single pass ink jet printer includes a plurality of ink jet modules arranged in adjacent rows extending across the width of the surface of an object which is moved with respect to the printer. The modules are mounted on and joined to a manifold which is mounted in a support frame. Ink is supplied to the manifold through an opening in the frame and the manifold distributes the ink to corresponding openings in the ink jet modules where it is directed to arrays of ink pressure chambers and to an outlet which communicates with a corresponding return passage in the manifold leading back to the ink supply. As a result, ink is circulated continuously through all of the ink jet modules, thereby maintaining pigment in suspension in a pigmented ink. An ink supply is removably connected to the printhead through quick-disconnect couplings and, to prevent contamination of the ink in the printhead, filters are provided in the ink supply and at the inlet to the printhead.

Abstract: In the high-frequency drop-on-demand ink jet system described in the specification, a variable impedance characteristic of an ink jet orifice is utilized to provide maximum drop ejection rates exceeding the maximum rates possible with constant orifice impedance characteristics. In one embodiment, successive negative, positive and negative pulses are applied to eject each drop in order to utilize a nonlinear orifice impedance characteristic, permitting maximum ink drop ejection rates exceeding 10-20 kHz and up to 150-200 kHz, and, in another embodiment, the ink jet orifice is designed with a bellmouth shape arranged to enhance the variable impedance characteristic.

Abstract: In the particular embodiments of the invention described in the specification, an ink jet system has a plurality of modular ink jet arrays arranged to produce high resolution images on a substrate. In one embodiment, the ink jet arrays are formed in an ink chamber plate in rows and columns providing a hexagonal pattern with ink chambers on one side of the plate and orifice passages leading from the ink chambers to an orifice plate on the opposite side of the ink chamber plate and a piezoelectric transducer mounted adjacent to the ink chambers has actuating electrodes adjacent to each of the ink chambers. Ink supply ducts, which extend in the ink chamber plate between the rows of ink jets to supply ink thereto, have one wall provided by an orifice plate affixed to the ink chamber plate.

Abstract: In the embodiments described in the specification, electrodes are bonded to the surface of a ceramic piezoelectric layer by supporting electrodes having a reduced dimension on a flexible dielectric film and placing the dielectric film under tension to expand the film and the electrodes sufficiently to conform the electrodes to the desired electrode pattern on the ceramic piezoelectric layer. The electrodes are then bonded to the piezoelectric layer with an adhesive bonding agent under pressure applied hydraulically so as to be distributed uniformly throughout the surface of the piezoelectric layer. In one embodiment the dielectric film also carries conductor arrays for connecting the electrodes to remote driver chips at locations spaced from the surface of the piezoelectric layer.

Abstract: An exclusively digital timing engine that measures extremely short time intervals for use in time of flight systems such as laser range finding systems. This exclusively digital timing engine minimizes the use of high speed, high cost components by employing a novel time multiplexing scheme to execute each of the primary time of flight functions: frequency synthesis, range gating, and time of flight interval measurement. In addition, the timing engine incorporates a random time delay scheme which enhances the resolution of the time interval measurement.

Abstract: In the ink jet head described in the specification, a reservoir body contains three ink reservoirs and a vacuum reservoir and a cover plate at the front of the reservoir body provides passages to supply ink from the ink reservoirs to an ink jet array from which ink is selectively ejected in response to electrical signals. Air-permeable, ink-impermeable membranes in a lung plate adjacent to the cover plate provide one wall of the ink passages, and the opposite sides of the membranes communicate with the vacuum reservoir. The reservoir body is made of a heat-conductive material and is removably received in an insulating housing containing a cartridge heater which supplies heat to the bottom of the reservoir body.

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 representative embodiments disclosed in the specification, an ink jet system includes a carriage for driving an ink jet head having a reservoir containing ink in a reciprocating motion and a counter for counting ink drops ejected through orifices in the ink jet head, and a nonvolatile memory for storing a number corresponding to the number of drops ejected and for generating a signal to terminate operation of the head or to produce a warning signal or to permit completion of printing of a sheet being printed when the number in the memory reaches a selected value. The ink jet head, which is removable from the system, has a refillable reservoir and, to prevent unauthorized refilling, a security arrangement utilizing a special code or a fuse is provided.

Abstract: In the particular embodiments described in the specification, a thin-film PZT piezoelectric transducer ink jet head includes a dielectric layer with electrodes and a thin film piezoelectric layer having a thickness in the range of 1-25 microns including one or more layers of perovskite-seeded PZT material and a further pattern of electrodes on the surface of the PZT layer along with a silicon substrate containing openings to provide ink chambers in the region of the electrodes. An orifice plate affixed to the substrate encloses the ink.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon plate is formed with orifice passages extending through the plate, pressure chambers on one side of the plate, flow-through passages on the other side of the plate and ink supply passages, and a piezoelectric plate having a conductive coating on the exposed side is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. The conductive coating on the piezoelectric plate is photo-etched to produce an electrode pattern corresponding to the pattern of the pressure chambers in the carbon plate, and an orifice plate is affixed by a thin layer of epoxy adhesive to the opposite surface of the carbon plate with orifices aligned with the orifice passages in the carbon plate.

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: An ink jet head has a reservoir containing hot melt ink and an orifice plate with orifices, along with passages leading from the reservoir to the orifices to conduct ink thereto. The ink jet head includes a heater to melt the ink in the reservoir, along with a further heater to heat air in the airspace above the ink in the reservoir, and the reservoir has a sealable vent which is sealed by a sealing element at a maintenance station so that heating of the air increases the pressure in the reservoir to cause purging, an absorbent member being provided at the maintenance station adjacent to the orifice plate to trap ink ejected during purging.

Abstract: In the embodiments disclosed in the specification, a mounting arrangement for a replaceable ink jet head on a reciprocating carriage includes corresponding mounting pads on a rearwardly-facing surface of the carriage and on a forwardly-facing surface of the ink jet head and resilient electrical contacts on a rearwardly-facing surface of the ink jet head. In one embodiment, a clamp arrangement engages the rearwardly-facing surface of the ink jet head and includes a plurality of electrical contacts for engaging the electrical contacts on the rearwardly-facing surface of the ink jet head.

Abstract: In the particular embodiments described in the specification, a thin-film PZT piezoelectric transducer ink jet head is prepared by oxidizing one surface of a silicon wafer to provide a dielectric layer, forming electrodes on the layer by photoresist processing techniques, depositing one or more layers of perovskite-seeded PZT material to provide a thin-film piezoelectric layer having a thickness in the range of 1-25 microns, forming another pattern of electrodes on the surface of the PZT layer by photoresist techniques, and selectively etching the silicon substrate in the region of the electrodes to provide an ink chamber. Thereafter, an orifice plate is affixed to the substrate to enclose the ink chambers and provide an ink orifice for each of the chambers. An ink jet head having chambers 3.34 mm long by 0.17 mm wide by 0.15 mm deep and orifices spaced by 0.305 mm is provided.

Abstract: In the embodiments described in the specification, an ink jet system includes an ink jet head with an ink reservoir and a passage supplying ink from the reservoir to a plurality of pressure chambers from which ink drops are ejected through a corresponding plurality of orifices, along with a viscosity-detecting arrangement for detecting the viscosity of the ink supplied to the pressure chambers and a control system for controlling a heater so as to control the temperature of the ink in order to maintain viscosity at a desired level. In a particular embodiment, the ink-viscosity detector consists of four fluidic elements having different fluidic resistance and inertance values connected in a bridge circuit which is arranged to be balanced when the ink has the desired viscosity value.

Abstract: In the particular embodiments described in the specification, a thin-film transducer ink jet head has a substrate with a plurality of openings providing ink chambers and an orifice plate providing corresponding orifices and includes a thin-film piezoelectric transducer element on the side of the substrate opposite the orifice plate, which includes a piezoelectric film with a thickness in the range from 1-25 microns and an array of electrodes disposed on one surface of the piezoelectric film having at least three electrodes adjacent to each of the chambers, along with an arrangement for selectively applying different electric potentials to alternate electrodes in the array adjacent to each of the chambers.

Abstract: In the particular embodiments of the invention described in the specification, the surface of a hot melt ink image in a projection transparency having curved surface portions is reoriented to provide an ink layer of substantially uniform thickness causing rectilinear transmission of light rays passing through the transparency and provide a clear, saturated projection image. Reorienting of the curved surface portion to provide a layer of uniform thickness is accomplished by burnishing, pressing with or without heating, rolling with or without heating, or heating the ink to a temperature above its melting point for a selected time such as 0.5 to 10 seconds. Preferably, the ink is cooled rapidly after remelting to reduce crystallization and frosting and thereby reduce light transmission losses in the ink.