Abstract: An apparatus includes an inkjet assembly having inkjet nozzles through each of which ink flows at a nominal flow rate as it is ejected from the nozzle onto a substrate. Ink is held under a nominal negative pressure associated with a characteristic of a meniscus of the ink in the nozzle when ejection of ink from the nozzle is not occurring. The apparatus includes recirculation flow paths, each flow path having a nozzle end at which it opens into one of the nozzles and another location spaced from the nozzle end that is to be subjected to a recirculation pressure lower than the nominal negative pressure so that ink is recirculated from the nozzle through the flow path at a recirculation flow rate.

Abstract: An apparatus includes an inkjet assembly having inkjet nozzles through each of which ink flows at a nominal flow rate as it is ejected from the nozzle onto a substrate. Ink is held under a nominal negative pressure associated with a characteristic of a meniscus of the ink in the nozzle when ejection of ink from the nozzle is not occurring. The apparatus includes recirculation flow paths, each flow path having a nozzle end at which it opens into one of the nozzles and another location spaced from the nozzle end that is to be subjected to a recirculation pressure lower than the nominal negative pressure so that ink is recirculated from the nozzle through the flow path at a recirculation flow rate.

Abstract: Described herein is a method and apparatus for driving a drop ejection device to produce drops having straight trajectories. In one embodiment, a method for driving a drop ejection device having an actuator includes building a drop of a fluid with at least one drive pulse by applying a multi-pulse waveform having the at least one drive pulse and a straightening pulse to the actuator. Next, the method includes causing the drop ejection device to eject the drop with a straight trajectory in response to the pulses of the multi-pulse waveform. The straightening pulse is designed to ensure that the drop is ejected without a drop trajectory error.

Abstract: Described herein is a method and apparatus for driving a drop ejection device to produce variable sized drops with multi-pulse waveforms. In one embodiment, a method for driving a drop ejection device having an actuator includes applying a multi-pulse waveform having at least one drive pulse and at least one break off pulse to the actuator. The method further includes building a drop of a fluid with the at least one drive pulse. The method further includes accelerating the break off of the drop with the at least one break off pulse. The method further includes causing the drop ejection device to eject the drop of a fluid in response to the pulses of the multi-pulse waveform. The break off pulse causes the break off of the drop formed by the at least one drive pulse in order to reduce the tail mass of the drop.

Abstract: Described herein is a method and apparatus for driving a droplet ejection device with multi-pulse waveforms. In one embodiment, a method for driving a droplet ejection device having an actuator includes applying a multi-pulse waveform having two or more drive pulses and a cancellation pulse to the actuator. The method further includes generating a pressure response wave in a pumping chamber in response to each pulse. The method further includes causing the droplet ejection device to eject a droplet of a fluid in response to the drive pulses of the multi-pulse waveform. The method further includes canceling the pressure response waves associated with the drive pulses with the pressure response wave associated with the cancellation pulse.

Abstract: In one embodiment, a method for driving a droplet ejection device having an actuator includes applying a low power multi-pulse waveform having at least two drive pulses and at least one intermediate portion to the actuator. The method further includes alternately expanding and contracting a pumping chamber coupled to the actuator in response to the at least two drive pulses and the at least one intermediate portion. The method further includes causing the droplet ejection device to eject one or more droplets of a fluid in response to the pulses of the low power multi-pulse waveform. In some embodiments, at least one intermediate portion has a voltage level greater than zero and less than or equal to a threshold voltage level in order to reduce the power needed to operate the droplet ejection device.

Abstract: Described herein is a process and apparatus for driving a droplet ejection device with embedded multi-pulse waveforms. In one embodiment, the process includes generating a multi-pulse waveform that includes drive pulses in predetermined positions. Next, the process includes applying the drive pulses to the actuator and causing the droplet ejection device to eject a first droplet of a fluid. The process also includes applying a second multi-pulse waveform having at least one embedded pulse to the actuator and causing the droplet ejection device to eject a second droplet of the fluid. Each embedded pulse is embedded between predetermined positions of two drive pulses. In some embodiments, the first and second droplets have different droplet sizes and these droplets are ejected at substantially the same effective drop velocity.

Abstract: A method for causing ink to be ejected from an ink chamber of an ink jet printer includes causing a first bolus of ink to be extruded from the ink chamber; and following lapse of a selected interval, causing a second bolus of ink to be extruded from the ink chamber. The interval is selected to be greater than the reciprocal of the fundamental resonant frequency of the chamber, and such that the first bolus remains in contact with ink in the ink chamber at the time that the second bolus is extruded.

Abstract: Described herein is a method and apparatus for driving a drop ejection device to produce drops having straight trajectories. In one embodiment, a method for driving a drop ejection device having an actuator includes building a drop of a fluid with at least one drive pulse by applying a multi-pulse waveform having the at least one drive pulse and a straightening pulse to the actuator. Next, the method includes causing the drop ejection device to eject the drop with a straight trajectory in response to the pulses of the multi-pulse waveform. The straightening pulse is designed to ensure that the drop is ejected without a drop trajectory error.

Abstract: Described herein is a method and apparatus for driving a droplet ejection device with multi-pulse waveforms. In one embodiment, a method for driving a droplet ejection device having an actuator includes applying a multi-pulse waveform having two or more drive pulses and a cancellation pulse to the actuator. The method further includes generating a pressure response wave in a pumping chamber in response to each pulse. The method further includes causing the droplet ejection device to eject a droplet of a fluid in response to the drive pulses of the multi-pulse waveform. The method further includes canceling the pressure response waves associated with the drive pulses with the pressure response wave associated with the cancellation pulse.

Abstract: In one embodiment, a method for driving a droplet ejection device having an actuator includes applying a low power multi-pulse waveform having at least two drive pulses and at least one intermediate portion to the actuator. The method further includes alternately expanding and contracting a pumping chamber coupled to the actuator in response to the at least two drive pulses and the at least one intermediate portion. The method further includes causing the droplet ejection device to eject one or more droplets of a fluid in response to the pulses of the low power multi-pulse waveform. In some embodiments, at least one intermediate portion has a voltage level greater than zero and less than or equal to a threshold voltage level in order to reduce the power needed to operate the droplet ejection device.

Abstract: Described herein is a method and apparatus for driving a drop ejection device to produce variable sized drops with multi-pulse waveforms. In one embodiment, a method for driving a drop ejection device having an actuator includes applying a multi-pulse waveform having at least one drive pulse and at least one break off pulse to the actuator. The method further includes building a drop of a fluid with the at least one drive pulse. The method further includes accelerating the break off of the drop with the at least one break off pulse. The method further includes causing the drop ejection device to eject the drop of a fluid in response to the pulses of the multi-pulse waveform. The break off pulse causes the break off of the drop formed by the at least one drive pulse in order to reduce the tail mass of the drop.

Abstract: Described herein is a process and apparatus for driving a droplet ejection device with embedded multi-pulse waveforms. In one embodiment, the process includes generating a multi-pulse waveform that includes drive pulses in predetermined positions. Next, the process includes applying the drive pulses to the actuator and causing the droplet ejection device to eject a first droplet of a fluid. The process also includes applying a second multi-pulse waveform having at least one embedded pulse to the actuator and causing the droplet ejection device to eject a second droplet of the fluid. Each embedded pulse is embedded between predetermined positions of two drive pulses. In some embodiments, the first and second droplets have different droplet sizes and these droplets are ejected at substantially the same effective drop velocity.

Abstract: A method for causing ink to be ejected from an ink chamber of an ink jet printer includes causing a first bolus of ink to be extruded from the ink chamber; and following lapse of a selected interval, causing a second bolus of ink to be extruded from the ink chamber. The interval is selected to be greater than the reciprocal of the fundamental resonant frequency of the chamber, and such that the first bolus remains in contact with ink in the ink chamber at the time that the second bolus is extruded.

Abstract: In general, in one aspect, the invention features a method for driving a droplet ejection device having an actuator, including applying a multipulse waveform that includes two or more drive pulses to the actuator to cause the droplet ejection device to eject a single droplet of a fluid, wherein a frequency of the drive pulses is greater than a natural frequency, fj, of the droplet ejection device.

Abstract: A method for driving a droplet ejection device having an actuator, including applying a primary drive pulse to the actuator to cause the droplet ejection device to eject a droplet of fluid in a jetting direction, and applying one or more secondary drive pulses to the actuator which reduce a length of the droplet in the jetting direction without substantially changing a volume of the droplet.

Abstract: Ink jet printheads and printhead components are described.

Abstract: Ink jet printheads and printhead components are described.

Abstract: A fluid droplet ejection device including a body defining a plurality of fluid paths that each include an inlet including a flow restriction, a pumping chamber, and a nozzle opening communicating with the pumping chamber for discharging fluid droplets. An actuator is associated with each pumping chamber. The pumping chamber has a largest dimension that is sufficiently short and the flow restriction provides sufficient flow resistance so as to provide a fluid droplet velocity and/or volume versus frequency response that varies by less than plus or minus 25% over a droplet frequency range of 0 to 40 kHz. Also disclosed are fluid droplet ejection devices in which the ratio of the inlet flow resistance to the pumping chamber flow impedance is between 0.05 and 0.9, the pumping chamber has a time constant for decay of a pressure wave in the pumping chamber that is less than 25 microseconds.

Abstract: In general, in one aspect, the invention features a method for driving a droplet ejection device having an actuator, including applying a multipulse waveform that includes two or more drive pulses to the actuator to cause the droplet ejection device to eject a single droplet of a fluid, wherein a frequency of the drive pulses is greater than a natural frequency, fj, of the droplet ejection device.