Abstract: In the representative embodiments of an ink jet array described in the specification, a plurality of ink sources is arranged to provide different inks to selected orifices and a linear array of ink jet orifices is supplied with ink from pressure chambers alternately disposed on opposite sides of the array to permit close spacing of the ink jet orifice and adjacent pairs of orifices in the array receive ink from the same ink source. At the end opposite from the ink jet orifice, each pressure chamber having a compliant wall communicates with a low acoustic impedance chamber to reflect negative pressure pulses from the pressure chamber back through the chamber as positive pulses to reinforce positive pulses applied to the pressure chamber and to prevent pressure pulses from being transmitted to the ink supply.

Abstract: In the embodiments of the invention described in the specification, a four-color ink jet printer includes a transport mechanism for conveying a record medium in one direction and an ink jet head containing a black ink nozzle array and a primary color ink nozzle array for scanning the record medium in a transverse direction while projecting drops of ink onto the record medium. A control unit provides two printing speeds in which either high-quality or high-speed printing can be accomplished. For high-speed printing all of the nozzles of both arrays are used, and for high-quality printing one-third of the nozzles in the black ink array and all of the nozzles in the primary color ink nozzle array are used and the record medium is transported at one-third the rate used for high-speed printing.

Abstract: In the representative embodiments of an ink jet array described in the specification, a linear array of ink jet orifices is supplied with ink from pressure chambers alternately disposed on opposite sides of the array to permit close spacing of the ink jet orifices. At the end opposite from the ink jet orifice, each pressure chamber communicates with a low acoustic impedance chamber to reflect negative pressure pulses from the pressure chamber back through the chamber as positive pulses and to prevent pressure pulses from being transmitted to the ink supply. In addition, a high-impedance passage between the low acoustic impedance chamber associated with one pressure chamber and the pressure chamber for the adjacent ink jet provides a continuous flowthrough passage from the ink supply port for one ink jet to the ink supply port for an adjacent ink jet.

Abstract: In the shear mode piezoelectric transducer for an ink jet system described in the specification, a piezoelectric plate is polarized parallel to the plane of the plate and in directions extending away from the center of the pressure chamber with which the transducer is used, and electrodes mounted on opposite surfaces of the plate impose electric fields orthogonal to the direction of polarization. The resulting shear motion of the transducer decreases the volume of the pressure chamber, ejecting a drop of ink from an orifice communicating with the pressure chamber. The piezeelectric plate used in the transducer is prepared by imposing electric fields within the plate in the direction parallel to the plane of the plate between electrodes mounted on opposite sides of the plate in the central region of the pressure chamber and electrodes mounted on opposite sides of the plate in the peripheral regions of the pressure chamber.

Abstract: In the particular embodiments described in the specification, a transparency projector includes a transparent sheet having one surface formed with a field of corner reflectors in which corresponding surfaces of each of the corner reflectors are deviated from orthogonality. A transparency adjacent to the retrodirectional reflector sheet is illuminated by a light source adjacent to a projection lens and light reflected from the retrodirectional reflector sheet back through the transparency forms images of the light source at positions on each side of the light source which are within the aperture of the projection lens. A transparency having three-dimensional ink spots which form dioptric lenticules can be projected by the transparency projection system without degradation of color.

Abstract: A single piezoelectric transducer is used to drive an array of drop-on-demand ink jet ejectors. This is accomplished by utilizing a plurality of electrodes which divide the piezoelectric transducer into discrete, deformable sections, each section corresponding to an ejector.

Abstract: A pressure pulse liquid droplet ejecting method wherein an induced current within a liquid causes rapid formation of a vapor. The vapor expansion forces droplet ejection. In a preferred method, the induced current is focused by an intermediate dielectric layer placed in the liquid.

Abstract: A circuit for use in an ink jet printer in which the carriage motion either approximates a sinusoidal vibratory pattern, or which has any variable velocity pattern that reliably repeats from cycle to cycle. It is further assumed that the printer will print in both directions of the carriage, and that the flight time of the ink drop from jet to paper is constant. A counter starts at a value corresponding to the flight time of the ink drop, and then measures the time of the carriage over a predetermined distance. The difference is the required delay. A second delay counter uses this value to produce a time delay prior to ejecting the ink drop. Since, in an actual ink jet printer, several drops will be in transit at the same time, the circuit is provided with a plurality of phases or channels which operate concurrently.

Abstract: Horizontal interlacing is used in an oscillating bar drop-on-demand ink jet printer to improve image quality, particularly in solid black areas. The disclosed system provides a method for printing that allows the image-receiving surface to be forwarded continuously, reducing the requirement for stepwise operation.

Abstract: A pressure pulse drop ejector which incorporates a check valve at both ends of a tubular electromechanical transducer. The transducer is used both to radially squeeze ink through a check valve to an orifice and then by elongating, expressing a droplet from the orifice. The check valves provide the means necessary for preventing air ingestion into the drop ejector.

Abstract: A check valve for a drop-on-demand pressure pulse ejector for preventing pressure pulse loss to the liquid supply system. The check valve is made by electrodeposition onto the surface of a substrate.

Abstract: A method of minimizing crosstalk between transducer driven pulse liquid droplet ejectors in ejector arrays. An array mounted on a scanning carriage and having nozzles inclined to the direction of relative motion between the carriage and the print-receiving member is designed such that adjacent nozzles are not fired simultaneously. Similarly, an oscillating bar pulse ejector array is designed such that adjacent nozzles are not fired simultaneously.

Abstract: The invention relates to an oscillating bar drop-on demand ink jet printer where printing occurs while the bar is moving bidirectionally over a transversely moving record-receiving surface. Specifically, the invention relates to a method of increasing the effective print speed of such a printer by electrostatically compensating for the inherent velocity variation of the oscillating bar as it oscillates.

Abstract: Electrostatic deflection is used in an oscillating bar drop-on-demand ink jet printer to compensate for about one half of the droplet displacement caused by bar velocity. The disclosed system provides a method for printing that is not sensitive to variations in ink droplet ejection velocity.

Abstract: Electrostatic deflection is used to provide multiline printing from a single pass in an oscillating bar ink jet printer.

Abstract: Electrostatic deflection is used to correct velocity induced droplet placement errors in an oscillating bar ink jet printer.

Abstract: An oscillating bar drop-on-demand ink jet printer is used to print on a continuously moving record-receiving surface. The record-receiving surface moves in a direction orthogonal to the direction of oscillation of the oscillating bar, the resultant trace being a sine wave. Electrostatic deflection is utilized to square off the sine wave to a preferred rectangular trace.

Abstract: A method and apparatus for marking wherein an array of marking elements is used to mark on a continuously moving mark-receiving surface. In order to provide a rectangular grid in an efficient manner, the array is oscillated both perpendicular and parallel to the direction of movement of the mark-receiving surface.

Abstract: A coincidence ink jet principle is disclosed wherein each ink jet has two inlet passages communicated to an outlet orifice. Each inlet passage is communicated to a respective transducer chamber. The fluid displacement and fluid velocity effected by a pressure pulse generated by each transducer chamber in a respective inlet passage is insufficient to express a droplet from the orifice. However, the combined fluid displacement and fluid velocity, which is the result of the pressure pulses generated by the transducers being coincident at the orifice, will result in a droplet being expressed from the orifice.In one system disclosed utilizing the above described principle, each inlet passage of a jet is communicated to a respective transducer and each transducer is connected to a respective electronic driver. In this system, the number of electronic drivers and transducer chambers are substantially less than the number of ink jets. These transducer chambers are time shared for expressing an ink droplet.

Abstract: An improved suspension for an axially oscillating bar. The suspension is a trifurcated spring, the bar being attached to the central section of the spring. The spring may be mounted to act as a multiple cantilever spring. Preferably, two matching springs are used to suspend the bar.