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: 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.