Abstract: Ink jet printers used for printing large characters employ a separate solenoid valve for each drop stream which forms part of a printhead matrix. By optimizing the frequency response of the nozzle/valve sub system (primarily the connecting tubing), higher operating frequencies can be obtained. It has been found that a ratio of six to one between subsystem resonant frequency and operating frequency provides greatly improved printing.

Abstract: A method and composition for printing images onto substrates that are to be subsequently subjected to temperatures of at least 500.degree. F., comprising printing onto said substrate, by ink jet printing, an ink composition comprising a dispersion of synthetic pigment particles that have a particle size from about 0.02 to about 0.20 microns, with at least about 90 percent of said particles having diameters less than about 0.1 micron, and subsequently subjecting said substrate to said temperature.

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: A control system is disclosed for an ink jet printer. The control system employs acoustic transducers to determine the velocity of sound in the ink and in a reference chamber containing only fresh ink. By comparing the two measurements it can be determined when to add additional solvent to the system to maintain solids concentration substantially constant.

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 for controlling the flight time and composition of a marking fluid used in a continuous jet marking system. A three-way valve permits switching between fresh ink and system ink supplies. Periodically a comparison of pressure required to maintain a constant drop flight time is made by a controller. Because both supplies are in the same operating environment any difference in pressure is due to a change in system ink viscosity. Solvent is added, if necessary, to the system ink via a pump to restore viscosity to desired values.

Abstract: A pilot nozzle is provided for a multi-jet printing head. The pilot nozzle is continuously monitored to detect changes in phase due to changes in ink temperature, viscosity, pressure or other reason. Should a change occur requiring that the pilot nozzle be operated on a different clock phase, this change is made to all of the nozzles, without interrupting printing. The pilot nozzle is not used for printing, but is continuously monitored for the sole purpose of detecting phase changes.

Abstract: A system for analyzing the physical condition of a moving article, such as a glass bottle, in a stream of articles of manufacture which are moving at a predetermined speed. A light source illuminates a portion of the moving article to be analyzed at an illumination angle, and a camera obtains an image of the illuminated portion of the article. The camera is disposed to view the article at a viewing angle that is distinct from the illumination angle, thereby substantially reducing the amount of reflected light received by the camera. A transparent surface is interposed between the camera and the article and angled to reduce the amount of reflected light received by the camera. A computer or the like processes the image to evaluate the physical condition of the article, and categorizes the article into distinct categories based upon the physical condition of the article.

Abstract: The present invention provides an ink composition for use in printing on food items, especially fruits and vegetables, and a method of forming printed images on food items by use of such compositions. The compositions of the present invention comprise a colorant, a binder, such as a wood rosin resin, and a carrier, such as ethanol. The composition is also characterized as being MEK-free, as well as, acetone-free.

Abstract: A microprocessor-based control system for use in ink jet printers periodically measures flow rate of marking fluid, flow time or flight time of marking fluid drops and adjusts the voltage supplied to deflection electrodes-to maintain constant character height notwithstanding changes in the printer operating environment that would otherwise result in undesirable variation in character height. An alternate embodiment uses the flow time, flow rate or flight time information to adjust the charge amplifier gain, rather than the deflection voltage, to achieve the same result.

Abstract: An ink composition suitable for ink jet printing operations, comprising a colorant, water, and surfactant, said composition having a surface tension of less than about 30 dynes/cm.

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 latent image printing process comprising applying to a substrate a latent image ink composition, with an ink jet printer. Subsequently, the latent image is activated to render it visible, by application of an activator. The present invention also provides a latent ink composition for use in ink jet applications, which is capable of being applied to a white or light colored substrate to form latent printed images that are substantially invisible until activated.

Abstract: An ink composition suitable for drop-on-demand ink jet printing on porous substrates comprising water, a colorant, a non-teratogenic and non-carcinogenic humectant, and a solid penetrant, which ink composition has a volatile organic content of less than 300 grams per liter.

Abstract: A hot melt ink comprising, ionomers and an image-forming agent, wherein the melting point of the ionomers is from about 50.degree. C. to about 130.degree. C., said ink exhibiting, in the molten stage, a viscosity from about 5 to about 60 centipoises (cps) at about 90.degree. to 140.degree. C. A method for ink jet printing comprising application of said ink in the molten state is also disclosed. A hot melt ink jet composition comprising a solid carrier component, an image-forming composition, and from about 5 to about 75 percent, by weight of an emulsifier is also disclosed, and the use thereof for ink jet printing.

Abstract: The printhead of an ink jet printer includes an electrically conductive plastic chassis and charging electrode. The plastic chassis can be constructed of plastic resins such as polyester, nylon, acetal, and polyphenylene sulphide imbedded with electrically conductive fibers such as carbon and stainless steel. The fibers can be coated with nickel to improve the shielding characteristics of the material.

Abstract: A base for operative association with an operating mechanism sensitive to horizontal vibration, such as an ink jet printer, supports a horizontal document feeder plate and associated drive operative to advance documents in sequential fashion from a stack toward the operating mechanism. A drive linkage interconnects a rotatable drive shaft to the feeder plate to effect horizontal reciprocating movement thereof. A counterweight is associated with the drive so as to substantially offset or nullify horizontal inertia forces imparted to the base by the feeder plate whereby to minimize horizontal vibration of the base. In an embodiment utilized for intermittent feeding of documents to the operating mechanism, a balance arm and associated counterweight cooperate with the feeder plate to offset horizontal inertia forces imparted to the base, and also minimize start-up torque required to initiate reciprocating movement of the feeder plate after stoppage.

Abstract: An ink composition suitable for ink jet printing operations comprising an aqueous resin solution and an organic pigment where said ink composition is substantially free of volatile organic compounds. Compositions are provided that form printed images that are solvent resistant to with isopropanol, ethanol, water, and mixtures thereof, and are retortable.

Abstract: A hot melt ink comprising, a eutectic composition and an image-forming agent, wherein the melting point of the eutectic composition is from about 80.degree. C. to about 130.degree. C. and the compounds present in the eutectic compositions have melting points of at least about 100.degree. C. Also disclosed is a method for ink jet printing comprising:(a) providing a thermally reversible hot melt ink which is a solid at ambient temperature and a liquid at temperatures between about 80.degree. C.-130.degree. C., said ink comprising:(i) a eutectic composition; and(ii) an image-forming composition;(b) elevating the temperature of said eutectic composition to between about 90.degree. C. and about 140.degree. C., to cause said ink to form a liquid solution or suspension of said image-forming composition;(c) jetting said ink onto a substrate in the form of images;(d) allowing said ink to crystallize upon cooling on said substrate.

Abstract: A document handling system, such as a mailing machine, includes a feeder station operative to feed documents from a stack in sequential fashion to a conveyor belt of a transport station. The feeder and transport stations include discrete drive motor controllers operatively associated with a speed control adapted to apply a control signal to the transport controller and a control signal to the feeder controller. The feeder controller signal is slaved to the transport controller signal so as to enable changes in document feeder and transport speeds through a single control. A separate gap control enables selective adjustment of the gap between successive documents for various size documents.