Abstract: A continuous stream binary array ink jet print head includes an elongate cavity for containing ink and an array of nozzle orifices formed so as to extend through a wall of the cavity for passing the ink from the cavity to form jets. The nozzle orifices extend along the length of the cavity. The cavity is divided up along its length by at least one internal wall thereby to create a plurality of sub-cavities substantially acoustically isolated from one another and to divide up the array of nozzle orifices between the sub-cavities such that each sub-cavity communicates with one or more of the nozzle orifices of the array. One or more actuators associated with each sub-cavity cyclically varies the dimensions of the sub-cavity thereby to cause the or each jet emanating from the nozzle orifice(s) of that sub-cavity to break up into ink droplets at a predetermined distance therefrom. The droplets of each jet are selectively electrically charged and deflected.

Abstract: A droplet generator for a continuous stream inkjet print head has an elongate cavity for containing the ink and nozzle orifices in a wall of the cavity for passing the ink from the cavity to form jets. The nozzle orifices extend along the length of the cavity. An actuator is disposed so as to address the face of the cavity opposite the wall to vibrate the ink in the cavity such that each jet breaks up into ink droplets at substantially the same predetermined distance from the wall. The actuator has a plurality of constituent sub-actuators each capable of independent vibration. The combined coverage of the face of the cavity by the sub-actuators is such that the jet break up can be achieved without resonance of the cavity in its dimension from the wall to the face.

Abstract: A droplet generator for a continuous stream inkjet print head has an elongate cavity for containing the ink and nozzle orifices in a wall of the cavity for passing the ink from the cavity to form jets. The nozzle orifices extend along the length of the cavity. An actuator is disposed so as to address the face of the cavity opposite the wall to vibrate the ink in the cavity such that each jet breaks up into ink droplets at substantially the same predetermined distance from the wall. The actuator has a plurality of constituent sub-actuators each capable of independent vibration. The combined coverage of the face of the cavity by the sub-actuators is such that the jet break up can be achieved without resonance of the cavity in its dimension from the wall to the face.

Abstract: A continuous stream binary array ink jet print head comprising: an elongate cavity for containing the ink; an array of nozzle orifices (37) formed so as to extend through a wall of said cavity for passing ink from the cavity to form jets, said nozzle orifices (37) extending along the length of said cavity, said cavity being divided up along its length by at least one internal wall (33) thereby to create a plurality of sub-cavities (35) substantially acoustically isolated from one another, said dividing up of the cavity to form sub-cavities (35) correspondingly dividing up said array of nozzle orifices (37) between the sub-cavities (35) such that each sub-cavity communicates with one or more of the nozzle orifices (37) of the array; one or more actuator (39) means associated with each said sub-cavity for cyclically varying the dimensions of the sub-cavity thereby to cause the or each jet emanating from the nozzle orifice(s) of that sub-cavity to break up into ink droplets at a predetermined distance therefrom;

Abstract: A continuous stream ink jet print head has a droplet generator with an elongate cavity for containing the ink, and nozzle orifices in a wall of the cavity for passing ink from the cavity to form jets. The nozzle orifices are disposed at spaced positions along the length of the cavity. An actuator for vibrating the ink in the cavity is provided such that each jet breaks up into ink droplets at the same predetermined distance from the wall of the cavity. The actuator is disposed on the opposite side of the cavity to the wall, includes a vibrator which is divided up along the length of the cavity at least partially into at least two parts, and includes a backing member disposed further from the cavity than the vibrator and secured to and bridging the parts into which the vibrator is at least partially divided. The vibrator is interposed in line between the backing member and the cavity.

Abstract: A droplet generator for a continuous stream ink jet print head has a cavity for containing ink, and nozzle orifices passing ink from the cavity to form jets. An actuator means vibrates the ink in the cavity such that each jet breaks up into ink droplets. The actuator means is disposed on the opposite side of the cavity to the nozzle orifices, and a surrounding wall of the cavity extends between the actuator means and nozzle orifices for containing the ink therebetween. The surrounding wall has inner and outer constituent wall. The resistive component of the wave impedance of the outer wall passively damps vibration of the inner wall by dissipating its vibration; the reactive component of the wave impedance of the outer wall actively restrains vibration of the inner wall, ensuring that each jet breaks up into ink droplets at the same predetermined distance from its respective nozzle orifice.

Abstract: A droplet generator for a continuous stream ink jet print head has a cavity (3, 23) for containing the ink; nozzle orifices (17, 27) in a wall (9) of the cavity (3, 23) for passing the ink from the cavity (3, 23) to form jets; and first (11, 21) and a second (13, 25) actuator device for establishing in combined operation a travelling wave. The travelling wave travels from the fist actuator device (11, 21) through the ink to the second actuator device (13, 25) and passes in a direction substantially parallel to the wall (9) containing the nozzle orifices (17, 27).