Abstract: The disclosed continuous ink jet printer nozzle assembly defines a flow path having a powered sonic oscillator associated therewith for inputing vibrations to ink flowing in the path, and a cavity for holding closely adjacent but isolated from the ink flow path one or more sensors operable to detect ink vibrations and/or temperatures immediately downstream from the oscillator, whereby such sensed information can be used in feedback controls for changing input power to the oscillator and/or heater/cooler unit upstream of the oscillator, for stabilizing the printed ink pattern. The nozzle assembly further is formed of three subassemblies: an ink driver subassembly having the powered oscillator and sensor(s), and filter and orifice subassemblies respectively adapted to be connected in serial self-aligned sealed orientations to the exterior upstream and downstream sides of the ink driver subassembly, thereby allowing field replacement of the filter and/or orifice subassemblies.

Abstract: A method and apparatus for accurately determining and setting the optimal nozzle drive voltage for an ink jet printer. The current carried by charged test drops is monitored by a sensing electrode and ammeter while the nozzle drive voltage is slowly varied between minimum and maximum points. A plot of drop current versus nozzle drive voltage provides an accurate determination of the good printing window for the particular nozzle under the operating conditions presented. This arrangement can be used for calibrating a new nozzle in an existing printer or for calibrating a new ink or font to ensure that operation will occur within the desired print window.

Abstract: A drive control system is disclosed which automatically maintains nozzle drive voltage within a proper range. The control system monitors the state of the "intermediate satellites" positioned between ink drops used for printing. When these satellites are neither forward nor backward merging, a first cardinal point designated C(L) is identified. A second cardinal point, C(H), is determined when the drop breakoff point stops decreasing, relative to said nozzle, with increasing nozzle drive voltage. From the two cardinal values, a desired operating range for a particular ink can be computed and the control system automatically set. The computed value is essentially independent of temperature.

Abstract: Printing distortions caused by ink stream/charge tunnel misalignment, charge tunnel mis-dimensioning or a variation in drop spacing or changes in ink resistivity are corrected by measuring the actual induction co-efficients for a particular printer. For this purpose, charge sensors located along the ink stream or adjacent the ink catcher detect induced charges from which the induction co-efficients are calculated by a programmable controller. These co-efficients are used to adjust the charge tunnel voltages to reduce or eliminate printing distortion.

Abstract: A method and apparatus are disclosed in which deflection and print speed are controlled by varying the nozzle drive frequency to increase or decrease drop velocity thereby to control drop deflection. The variation is done in a manner to maintain the ratio .lambda./d and drop size substantially constant. By altering the drop velocity the transit time of the drops through the high voltage deflection field is changed, permitting increased or decreased deflection. The system includes a pressure controller, a velocity sensor, a variable frequency nozzle drive and a processor. Calculations and operations are performed by the processor, based on the size of an operator selected image.

Abstract: A drive control system automatically maintains nozzle drive voltage within a proper range. The control system monitors the state of the "intermediate satellites" positioned between ink drops used for printing. When these satellites are neither forwared nor backward merging, a first cardinal point designated C(L) is identified. A second cardinal point, C(H), is determined when the drop breakoff point stops decreasing, relative to said nozzle, with increasing nozzle drive voltage. From the two cardinal values, a desired operating range for a particular ink can be computed and the control system automatically set. The computed value is essentially independent of temperature.

Abstract: An element for a drop on demand ink jet printer employing a lever seal in a housing to control the frequency and quantity of ink delivered to a printing material such as paper.

Abstract: An ink jet nozzle having more than one fluid resonance in the frequency range of interest is achieved through multi-chamber construction techniques. If the dual resonances are sufficiently close together in frequency, a robust printing region is obtained relatively immune to variations in temperature, drive voltage and ink composition.

Abstract: An ink jet chamber communicates with an ink reservoir through an opening in a diaphragm plate. The chamber also includes a nozzle through which ink may be ejected on demand. A mass, such as a ball, is reciprocally driven into the diaphragm plate. The ball, upon striking the diaphragm, closes the chamber opening, pressurizing the ink in the chamber to eject a droplet from the nozzle. The ball is driven by a printer driver wire to which it may be attached. Large arrays may be constructed.

Abstract: A method and apparatus are disclosed which provide feedback control of ink viscosity in a drop marking system. The ink flow between two selected points is monitored and compared against a reference value by an electronic controller such as a microprocessor. In the event that a flow time deviation is sensed, appropriate action is taken to change the flow time. A temperature sensor input to the controller permits temperature compensation to maintain ink composition substantially constant.

Abstract: An ink jet nozzle assembly is produced from materials, such as polyphenylene sulfide. The resulting assembly is acoustically soft so that undersirable fluid and mechanical resonances are substantially attenuated.

Abstract: A method and apparatus for ink jet printing are disclosed which employ reverse charge coupling to increase character height. A video signal is utilized to modulate the charge ring voltage. Via a parallel path the ink in the nozzle is reversely charged by the video signal. Thus, as the ink drops are formed their electrical charge is greater than can be obtained under ordinary circumstances. This permits greater deflection of the drops resulting in larger characters on the printing media at the normal distance between media and nozzle or higher quality characters of the same size if the media is moved closer to the nozzle.

Abstract: An ink jet printing system includes an ink ejection head for providing ink drops which are selectively charged and deflected in accordance with their charge as they traverse a path toward a recording medium. An accumulator or "dump" is positioned, in the operating mode of the system, adjacent to the recording medium to catch ink drops directed away from the medium. Before the printing is started, the charging and deflecting units are displaced from the ink path, and the accumulator is abutting the ejection head, effectively capturing any ink emanating from the head. When the system has been pressurized and is in all respects ready for operation, the accumulator is displaced away from the ejection head and along the normal path of the ink drops, thus "catching" all the drops until it reaches its normal operating position adjacent the medium. The charging and deflecting units are then moved into their normal operating positions.

Abstract: In an ink drop writing system a vibrating nozzle is used to form drops which are thereafter deflected electrostatically whereby characters or wave forms are written on paper by the deflected drops. In order to minimize the variations in drive voltage requirements for the transducer that vibrates the nozzle, caused by changes in ink parameters which cause variations in the velocity of sound through the ink that is used, and in order to minimize variations in the drop separation time from the ink stream, with drive frequency variations, the length of the nozzle is selected so that its mechanical resonance frequency is very much higher than the frequency at which the nozzle is used. As a result, the length of the nozzle is considerably shorter than the nozzle lengths which have been used heretofore.

Abstract: An .Iadd.acoustically soft .Iaddend.ink jet nozzle .?.assembly is produced from materials, such as.!. .Iadd.for continuous jets. The nozzle is a tubular member formed from .Iaddend.polyphenylene sulfide.?.. The resulting assembly is acoustically soft so that undesirable fluid and mechanical resonances are.!. (.Iadd.RYTON) which has a .Iaddend.substantially .?.attenuated.!. .Iadd.constant response over a transducer range of 10-100 KHz.Iaddend..