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: An ink jet apparatus having a scanning head employing at least one ink jet with a variable volume chamber which includes an ink droplet ejecting orifice, and a transducer, having a length mode resonant frequency, adapted to expand and contract along an axis of elongation in response to an electric field substantially transverse to the axis of elongation for ejection of droplets on demand from the ink droplet ejecting orifice is acoustically microstreamed by exciting the transducers during non-printing periods to eliminate start-up problems and to maintain pigments or other particles in dispersion within the ink.

Abstract: A high performance ink jet is operated in a fill-before-fire mode. The ink jet is characterized by at least one resonant frequency in excess of 10 kHz creating an upper limit for a frequency of stable operation. During operation, the ink jet is characterized by ejecting droplets of substantially equal velocity and/or size for various frequencies in an operating range extending from 0 to a fequency equal to or in excess of 5 kHz.

Abstract: A method for both reducing the ligament length and satellite droplet problems associated with producing high velocity ink droplets from an ink jet head printing at relatively high ink jet head transport speeds, comprises driving the ink jet head with a composite waveform including independent and successive first, second, and third electrical pulses, each having an exponential leading edge and a step-like trailing edge, the pulses being constructed to have amplitudes, pulse widths, and dead times between pulses, for causing the ink jet head to eject three successive ink droplets, each of increased velocity relative to the preceding droplet, for causing the droplets to merge in flight fo form a single or ultimate droplet having a predetermined velocity.

Abstract: An ink jet includes a variable volume chamber with an ink droplet ejecting orifice. The volume of the chamber is varied by a transducer which expands and contracts in a direction having at least a component extending parallel with the axis ink droplet ejection from the orifice. The transducer communicates with a moveable wall of the chamber which has a sufficiently small are a such that the difference in the pressure pulse transit times from each point on the wall to the ink droplet ejection orifice is less than 1 microsecond.

Abstract: The volume of the ink chamber of an ink jet device is rapidly expanded for pulling back into the chamber from an orifice a meniscus of ink, for forming a cusp shaped disturbance on the meniscus, thereby causing a relatively small droplet of ink to form and break off from the meniscus, and be ejected or propelled out of the orifice.

Abstract: An improved method for operating an ink jet device comprises the steps of: First, operating the transducer of the device for initiating the ejection of an ink droplet from an orifice via a first pressure disturbance within the ink chamber associated with the orifice; and thereafter, prior to the ejection of an ink droplet from the orifice, operating the transducer for producing a second pressure disturbance, lower in amplitude than the first pressure disturbance, for increasing stability by causing earlier break-off of the droplet at the orifice relative to the time of break-off without using the second pressure disturbance.

Abstract: The transducer of a demand ink jet is driven by voltage so as to project a droplet of ink from the orifice of an ink chamber on demand. After the chamber of the jet has been filled, an abrupt change in drive voltage level of the transducer disturbs the meniscus of ink in the orifice of the jet so as to move the meniscus away from the chamber. When the meniscus has reached a predetermined position and velocity in the orifice, the drive voltage level supplied to the transducer is substantially changed so as to eject the droplet from the orifice. The change in drive voltage level is contoured so as to minimize high frequency components. An array of ink jets may be similarly driven where the differences from jet to jet are compensated by wave shaping including variations from jet to jet in the period of time between perturbation and the substantial voltage level change leading to droplet projection.

Abstract: An ink jet includes a variable volume chamber with an ink droplet ejecting orifice. The volume of the chamber is varied by a transducer which expands and contracts in a direction having at least a component extending parallel with the axis ink droplet ejection from the orifice. The transducer communicates with a moveable wall of the chamber which has a sufficiently small area such that the difference in the pressure pulse transit times from each point on the wall to the ink droplet ejection orifice is less than 1 microsecond.