Xerox Corporation

Marcus M Schnarr

Kenneth H Fischbeck

Demetris F Paraskevopoulos

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.

Method and apparatus for oscillating an array of marking elements

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. Actuation of the two transducer chambers communicated to a particular jet, in such a manner that the pressure pulses generated by the respective transducers coincide at the orifice, will effect expression of a droplet therefrom. In another system disclosed utilizing the above described principle, a master transducer chamber is communicated to a separate respective droplet expression transducer chamber and each droplet expression transducer chamber is connected to a respective electronic driver. In this system, the master transducer chamber is actuated to create at each orifice a pressure pulse which is below the threshold pressure pulse for expressing an ink droplet therefrom. Actuation of any of the droplet expression transducer chambers to generate a pressure pulse which coincides at a particular orifice with the pressure pulse generated by the master transducer, will bring the resultant pressure pulse at the orifice above threshold to effect expression of the droplet from a particular orifice.

Coincidence fluid displacement and velocity expression of droplet

In a coincidence vector gate ink jet, a droplet is expressed from an outlet orifice by a coincident pressure produced by a pair of transducers at an outlet orifice. In this type of ink jet, it is normal for one of a cooperating pair of transducers to be activated in a non-coincident mode. In the non-coincident mode, a droplet is not expressed from an outlet orifice as long as the pressure produced by the one transducer remains below a given threshold. A certain type of pressure absorbing chamber is provided for a specific coincident gate ink jet array, which permits this threshold pressure to be substantially increased to a level substantially above the minimum coincident pressure produced by the pair of transducers to express a droplet from the orifice. This increase in the threshold pressure is an increase in the operating window. A greater operating window permits greater latitudes in manufacturing variation and permits greater latitudes in pressure variation to change the size of a droplet to effect halftoning.

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Lewisville, TX, United States of America

Marcus M Schnarr