A liquid discharge apparatus includes: an modulation circuit that generates a modulated signal by pulse-modulating a source signal through self-oscillation; a transistor that amplifies the modulated signal to generate an amplified modulated signal; a low-pass filter that includes an inductor and a capacitor and smoothes the amplified modulated signal to generate a drive signal; a feedback circuit that allows the drive signal to return to the modulation circuit; a piezoelectric element that is displaced by application of the drive signal thereto; a cavity that is filled with a liquid inside and has an internal volume which changes when the piezoelectric element is displaced; and a nozzle that is provided to discharge the liquid inside the cavity in response to the change of the internal volume of the cavity. In this configuration, a self-resonant frequency of the capacitor is higher than a frequency of the self-oscillation.

In accordance with an embodiment, an inkjet head comprises a first actuator and a second actuator, a first electrode, a second electrode, a third electrode, and a drive controller. The first actuator and the second actuator constitute a pressure chamber. The first electrode comes in contact with the first actuator from the outer side of the pressure chamber. The second electrode comes in contact with the first actuator and the second actuator from the inner side of the pressure chamber. The third electrode comes in contact with the second actuator from the outer side of the pressure chamber. The drive control section outputs an auxiliary pulse which generates volume change in the pressure chamber that is smaller than volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber to the first electrode, the second electrode, and the third electrode.

A drive system for individually switched nozzles with common drive signals of an inkjet print head, including a nozzle controller associated with each nozzle whereby meniscus activation is determined by a meniscus activation pulse, MAP, signal to that nozzle. A MAP controller defines a parameter for each nozzle such that the parameter is monitored by the MAP controller whereby a MAP signal is provided to the nozzle controller as required dependent upon the parameter, each nozzle configured whereby once the MAP signal is provided to provide meniscus activation at the nozzle any further nozzle fire signals, in the form of the common drive signals after the MAP signal, are delayed at least until the meniscus activation at the nozzle is complete while the nozzle controller ensures all the nozzle fire signals as common drive signals remain in sequence with each other.

A droplet ejection apparatus includes, a droplet ejection head, wherein the droplet ejection head includes a nozzle communicated with a pressure chamber, a first piezoelectric element configured to pressure liquid in the pressure chamber so as to cause a droplet to be ejected, and a second piezoelectric element capable of pressuring the liquid in the pressure chamber, a first drive waveform generation unit configured to generate a first drive waveform to be applied to the first piezoelectric element, a second drive waveform generation unit configured to generate a second drive waveform to be applied to the second piezoelectric element, and a control unit configured to apply the second drive waveform to the second piezoelectric element after the first piezoelectric element is driven due to the applied first drive waveform. Residual vibration of the liquid in the pressure chamber is suppressed by a vibration caused by the second piezoelectric element.

In a method for operating an inkjet print head for generating a droplet of a liquid, the inkjet print head comprises a number of ejection units, each ejection unit comprising a piezo-electric actuator having a signal electrode, a common electrode and a piezo-electric layer interposed between the signal electrode and the common electrode. The method comprises providing a non-jetting pulse signal on a common electrode, wherein the non-jetting pulse signal is adapted to generate a pressure wave in the liquid in the corresponding ejection unit without expelling a droplet of the liquid. The method further comprises providing a jetting pulse signal on a signal electrode, wherein the jetting pulse signal is adapted to generate a pressure wave in the liquid in the corresponding ejection unit such that a droplet of the liquid is expelled.

Further, an inkjet print head assembly comprising an inkjet print head and a control circuitry is provided. The inkjet print head assembly is configured for performing the above method.

Systems and methods of mitigating the effects of crosstalk in an inkjet head. An inkjet head has ink channels that jet droplets of a liquid material using piezoelectric actuators. Drive waveforms provided to the piezoelectric actuators include jetting pulses that cause activation of the piezoelectric actuators to jet the droplets from the ink channels. When crosstalk exists between the ink channels of the inkjet head due to the piezoelectric actuators, the amplitude of the jetting pulses are modified to mitigate the crosstalk between the ink channels.

A liquid ejecting apparatus includes an ejecting unit that includes a piezoelectric element which is displaced by a first drive signal or a second drive signal; a first unit circuit that generates the first drive signal by using a first pair of transistors; a second unit circuit that generates the second drive signal by using a second pair of transistors; and an adjustment unit that delays at least one of a first control signal and a second control signal to supply the delayed control signal to a corresponding unit circuit, in a case where timing when a level of the first control signal for controlling the first pair of transistors changes and timing when a level of the second control signal for controlling the second pair of transistors changes are within a threshold time, and in a case where a predetermined condition is satisfied.

A liquid ejecting apparatus includes an ejecting unit that includes a piezoelectric element which is displaced by a drive signal, a differential amplifier that outputs a control signal based on a source drive signal which is a source signal of the drive signal and a signal based on the drive signal, a pair of transistors that include a high-side transistor and a low-side transistor which are controlled based on the control signal and outputs the drive signal from an output terminal, a selector that selects one of the high-side transistor and the low-side transistor and supplies the control signal to the selected transistor, a first resistance element having one terminal that is electrically coupled to the output terminal, and a second resistance element having one terminal that is electrically coupled to the output terminal.

A liquid ejecting apparatus includes an ejecting unit that includes a piezoelectric element which is displaced by a drive signal; a differential amplifier that outputs a control signal based on a source drive signal which is a source signal of the drive signal and a signal based on the drive signal; a pair of transistors that include a high-side transistor and a low-side transistor which are controlled based on the control signal and outputs the drive signal from an output terminal; a selector that selects one of the high-side transistor and the low-side transistor and supplies the control signal to the selected transistor; a first resistance element for pulling up the output terminal; and a second resistance element for pulling down the output terminal. The first resistance element or the second resistance element has a variable resistance value.

A liquid ejecting apparatus includes an ejecting unit, a differential amplifier, a pair of transistors, and a selector. The ejecting unit includes a piezoelectric element which is configured to be displaced by a drive signal being applied to the piezoelectric element. The ejecting unit is configured to eject liquid in accordance with displacement of the piezoelectric element. The differential amplifier is configured to output a control signal based on a source drive signal which is a source signal of the drive signal and a signal based on the drive signal. The transistors includes a high-side transistor and a low-side transistor which are configured to be controlled based on the control signal and are configured to output the drive signal from an output terminal of the transistors. The selector is configured to select one of the high-side transistor and the low-side transistor and supply the control signal to a selected transistor.