Abstract: Determination of a maximum jetting frequency for an inkjet head. The method includes generating a velocity/frequency curve for an inkjet head, and determining failure zones in the velocity/frequency curve that comprise frequencies in the velocity/frequency curve resulting in jetting failure of the inkjet head. The method further includes determining a range of maximum jetting frequencies of the inkjet head that are higher than the frequencies of the failure zones, wherein subharmonic frequencies of each of the maximum jetting frequencies are outside of the failure zones. The method further includes selecting the maximum jetting frequency for the inkjet head from the range of maximum jetting frequencies.

Abstract: A method and apparatus to prevent ink starvation includes keeping ink in a primary common reservoir at a high pressure. The ink is transferred from the primary common reservoir to a local reservoir when a pressure drop across a restrictor decreases pressure in the local reservoir. The pressure drop across a restrictor results from a higher ink flow rate due to rapid firing of the transducer.

Abstract: A piezo-electric inkjet printing system includes an array of transducers. The array includes at least a first transducer and a second transducer. The first transducer is coupled to a first foot, and elongates in response to a first stimulus, causing ink to eject from a first ink chamber. The second transducer is coupled to a second foot, and elongates in response to a second stimulus, causing ink to eject from a second ink chamber. The first transducer is mechanically isolated from the second transducer.

Abstract: A piezo-electric inkjet printing system includes an array of transducers. The array includes at least a first transducer and a second transducer. The first transducer is coupled to a first foot, and elongates in response to a first stimulus, causing ink to eject from a first ink chamber. The second transducer is coupled to a second foot, and elongates in response to a second stimulus, causing ink to eject from a second ink chamber. The first transducer is mechanically isolated from the second transducer.

Abstract: A method and apparatus to prevent ink starvation includes keeping ink in a primary common reservoir at a high pressure. The ink is transferred from the primary common reservoir to a local reservoir when a pressure drop across a restrictor decreases pressure in the local reservoir. The pressure drop across a restrictor results from a higher ink flow rate due to rapid firing of the transducer.

Abstract: An inkjet printing system includes an array of transducers to eject ink, the array including the transducers divided into interspersed sets. A controller controls a firing sequence of the array of transducers. One set of transducers is fired, and after a delay, another set of transducers is fired and then, after further delays, each set is fired in turn. The delays are selected based on known response characteristics of the array of transducers to minimize the average crosstalk for all of the sets.

Abstract: An ink jet printhead composed of: a reservoir storing a quantity of printing ink, an ink manifold defining an ink supply volume in communication with the reservoir for holding a supply of ink received from the reservoir and a plurality of individually controlled ink jet delivery channels, each of the channels having an ink drop ejection transducer and an orifice to eject successive ink drops on demand in response to pressure pulses produced by the transducer, and each of the channels being in communication with the ink supply volume for receiving ink from the ink supply volume. The manifold is constructed to give the ink supply volume a large acoustic compliance to minimize propagation of pressure disturbances in the ink supply volume and acoustic signal crosstalk between the channels.

Abstract: A low pressure filtration and thickening device comprising a tank having a plurality of suspended filter elements therein and a plurality of filtrate receiving compartments in the upper portion of the tank for receiving filtrate from the filter elements wherein a filtrate discharge system is provided for providing separate and uninterrupted flow paths for the filtrate from the filter tank to a storage tank.

Abstract: A nozzle type centrifuge having a bottom feed inlet to a main pumping chamber at the base of the machine for injecting the feed slurry to a rotor bowl having separator discs for effecting a two-fraction separation comprising an overflow at the top and an underflow at the peripheral mid portion of the bowl with a portion of the underflow delivered to a return pumping chamber beneath the main pumping chamber and seal means between said chambers to prevent dilution of the underflow fraction.