Abstract: A control device of controlling a liquid droplet ejection head includes a head substrate; a head controller applying a drive voltage to the head substrate to control the ejection of liquid droplets; a relay substrate connecting the head substrate and the head controller; a main-body controller controlling the head controller; and a voltage conversion circuit disposed in the relay substrate. Further, the voltage conversion circuit converts a resistance value in accordance with a temperature of the head substrate into an output voltage, the relay substrate inputs the output voltage into the main-body controller, and the main-body controller detects the temperature based on the output voltage and determines the drive voltage based on the detected temperature.

Abstract: An ink jet recording apparatus includes a liquid-ejecting head including a pressure-generating chamber filled with a photocurable ink composition containing a polymerizable functional group-containing compound and water, a nozzle communicating with the pressure-generating chamber and ejecting a droplet of the photocurable ink composition, and a pressure-generating member causing a pressure change in the pressure-generating chamber; and an ejection pulse-generating unit generating an ejection pulse for driving the pressure-generating member.

Abstract: A plurality of THs are formed in the main substrate (drive substrate) in a region in which switching transistors are disposed. In addition, a solid pattern obtained by expanding an interconnection pattern at the periphery of the transistors is formed to surround the transistors. In addition, a solid pattern for heat dissipation is also formed on a rear surface to add a heat dissipation structure for a frame. According to this, it is possible to provide a liquid ejecting apparatus which has a simple configuration and which realizes operation stability without using a dedicated heat dissipation component.

Abstract: A liquid discharging apparatus including: a nozzle which discharges a liquid; a pressure chamber which communicates with the nozzle; a piezoelectric element which is provided in order to discharge the liquid corresponding to the pressure chamber; a driving signal generation unit which generates a driving signal in order to drive the piezoelectric element; and a residual vibration detection unit which detects a residual vibration. The driving signal generation unit generates a driving signal for inspection which is a first electric potential during a first period, is a second electric potential during a second period, is a third electric potential during a third period, is shifted from the first electric potential to the second electric potential, and is shifted from the second electric potential to the third electric potential. The third electric potential is an electric potential between the first electric potential and the second electric potential.

Abstract: A method and apparatus for printing is disclosed. The printing is done with multiple printhead dies. The nozzles in the different printhead dies are fired using different phases in an up-sampled encoder signal. The different phases correspond to a print offset between the different printhead dies.

Abstract: A liquid ejecting apparatus includes: a heating unit which heats a medium; a head which ejects liquid droplets onto the medium opposed thereto; and a driving signal generating unit which generates a driving signal to be applied to the head in order to eject the liquid droplets and which generates a driving signal different in accordance with whether the heating unit is used.

Abstract: Disclosed is a printing apparatus that forms a color image and a background image on a medium by repeating a dot formation operation of causing ink to be discharged from a first nozzle array and a second nozzle array moving in a moving direction so as to form the color dot and the background dot on the medium and a transport operation of transporting the medium in a transport direction, wherein a pixel in which the background dot is formed on the color dot and a pixel in which the color dot is formed on the background dot are mixed so as to form an area where the color image and the background image overlap.

Abstract: A drive device includes a circuit for selecting an arbitrary voltage among a plurality of kinds of voltages required for generating a drive signal for variably controlling potential applied to electrodes of channels. In the drive device, respective drive voltage input terminals and output terminals are respectively connected by a low-impedance connecting circuit which has low internal resistance, and a selected voltage input terminal and the output terminals are connected by a high-impedance connecting circuit which has high internal resistance. The drive device controls a drive waveform transition pattern of a drive signal such that the drive signal is output via the high-impedance connecting circuit while the potential applied to the respective electrode simultaneously changes in the same direction out of a positive direction and a negative direction and that the drive signal is output via the low-impedance connecting circuit in the other cases.

Abstract: A liquid ejection device includes a head unit and a control unit. A driving signal generating portion of the control unit is configured to create a driving signal having at least one wave portion for ejecting the liquid from the nozzles. A signal converting portion of the control unit is configured to convert plural types of original control signals including an original latching signal and an original printing data signal into a single serial control signal having a serial form. A signal restoring portion of the head unit is configured to create plural types of restored control signals from the serial control signal received, the restored control signals including a restored latching signal and a restored printing data signal. The nozzles are configured and arranged to eject the liquid based on the driving signal, the restored latching signal, and the restored printing data signal.

Abstract: According to one embodiment, the inkjet head of an application example includes a pressure chamber for charging the ink, an actuator for changing the volume of the pressure chamber, a nozzle for discharging the ink inside the pressure chamber when the volume of the pressure chamber is changed, and a controller that, in the formation of one pixel by discharging ink drops from the nozzle, when the elapsed interval from discharging ink drops last time by the nozzle is less than the specified interval, outputs the discharging waveform corresponding to the ink drop number determined for the formation of the pixel, and when the elapsed interval is more than the specified interval, increases the number of ink drop discharge cycles above the number determined for the formation of the pixel.

Abstract: A minute vibration driving signal is configured to include a first signal section which generates a plurality of minute vibration driving pulses, and a second signal section which maintains potential to a constant level without generating the minute vibration driving pulse, and can select a first mode in which duration of the second signal section is set to T2 which is longer than duration T1 of the first signal section, and a second mode in which duration of the second signal section is set to T4 which is longer than T2.

Abstract: A head drive control unit generates and outputs a pulse formed of a first expansion waveform element to expand individual liquid chambers, a first contraction waveform element to contract the individual liquid chambers, a second expansion waveform element to expand the individual liquid chambers, and a second contraction waveform element to return the individual liquid chambers that have repeatedly expanded and contracted to an initial state. The first contraction waveform element serves as a waveform element that contracts the individual liquid chambers at a timing of resonance with a change in a pressure in the individual liquid chambers due to the first expansion waveform element. The second contraction waveform element serves as a waveform element that suppresses the change in the pressure in the individual liquid chambers.

Abstract: A liquid ejecting apparatus includes a first piezo-electric element; a first cavity; a first nozzle; a second piezo-electric element; a second cavity; a second nozzle; a drive signal generating section which generates a drive signal causing the first piezo-electric element or the second piezo-electric element to be displaced; a drive signal transmission path through which the drive signal is transmitted from the drive signal generating section to the first piezo-electric element or the second piezo-electric element; and a cable that forms at least a portion of the drive signal transmission path, the cable includes a drive signal transmitting wire which forms at least a portion of the drive signal transmission path and a shield wire in which potentials are fixed, and the drive signal transmitting wire has a characteristic impedance in a predetermined range.

Abstract: An apparatus includes an amplifier that employs a bias current to drive a print nozzle. A current reduction module can be employed to offset the bias current and to reduce a portion of the bias current from appearing in a subsequent stage to the amplifier in order to mitigate power in the subsequent stage.

Abstract: A drive signal includes a first drive pulse that causes liquid droplets to be ejected from nozzles and a second drive pulse that causes liquid droplets of a different size from those of the first drive pulse to be ejected from the nozzles. The drive pulses have expansion elements that expand a pressure chamber, contraction elements that contract a pressure chamber, and vibration control elements. An initiation potential of the contraction element of the first drive pulse and an initiation potential of the contraction element of the second drive pulse are the same. The differential voltage between the standard potential and the contraction potential is set to between 40% 50% or less of the potential between the initiation potential of the contraction element and the contraction potential.

Abstract: In a recording suspension period when a recording head is accelerated or decelerated in a non-recording region on a recording medium, or stops moving in the course of performing a printing process (printing job), a second driving signal is generated from a driving signal generation portion. Second vibration driving pulses of the second driving signal are applied to all piezoelectric elements, so that a vibration operation is performed without ejecting the liquid. Since a second reference potential of the second driving signal is set to be lower than a first reference potential of a first driving signal generated in a recording period as much as possible, a general potential (driving voltage) of the second driving signal is reduced, and reduce power consumption in the recording suspension period is reduced. As a result, it is possible to contribute to the power consumption saving of a printer.

Abstract: A drive signal includes a first drive pulse that causes liquid droplets to be ejected from nozzles and a second drive pulse that causes liquid droplets of a different size to those of the first drive pulse to be ejected from the nozzles. Each pulse includes at least an expansion element that causes a pressure chamber to expand by changing from a standard potential, which is a standard for changes in potential, to an expansion potential, a contraction element that causes the expanded pressure chamber to contract by changing from a potential that is on an expansion potential side of the standard potential to a contraction potential that exceeds the standard potential thereby ejecting the liquid. Initiation potentials of the contraction elements of the first and second drive pulses are made to be uniform at the same potential.

Abstract: In one embodiment, an actuator connected to a printhead structure is activated with a waveform to cause vibration of the structure sufficient to move fluid within a printhead channel adjacent to the structure and not cause the fluid to eject from the channel during a nonprinting period. In another embodiment, a first pulse module applies a pulse at a printhead structure at a combination of voltage, duration, and frequency to cause shaking of printhead structure to move fluid within a printhead channel adjacent to the structure without ejecting the fluid from the channel during a nonprinting period. In another embodiment, an actuator connected to a printhead structure is activated during a nonprinting period to pulse the structure to move fluid within a printhead channel adjacent to the structure without causing the fluid to be expelled from the channel.

Abstract: A fluid ejection device includes: a modulator adapted to pulse-modulate a drive waveform signal forming a basis of a drive signal of an actuator to obtain a modulated signal; a digital power amplifier circuit adapted to power-amplify the modulated signal to obtain a power-amplified modulated signal; a low pass filter adapted to smooth the power-amplified modulated signal to obtain the drive signal; and a power amplification stopping section operating when holding a voltage of the actuator constant.

Abstract: According to one embodiment, a driving device applies an ejection pulse signal that deforms a partition in such a way that an ink drop is ejected from a nozzle and an auxiliary pulse signal that deforms the partition to such an extent that an ink drop is not ejected from the nozzle, as a drive signal for providing a potential difference between electrodes, to an inkjet head at different timings so that the two pulse signals are not applied simultaneously. A constraint on output of the auxiliary pulse signal is significantly relaxed.

Abstract: A liquid ejection device includes a drive waveform generator generating a drive waveform signal; a modulator performing pulse modulation on a signal from the drive waveform generator to provide a modulated signal; a digital power amplifier performing power amplification on the modulated signal to provide an amplified digital signal; a lowpass filter smoothing the amplified digital signal to provide a drive signal of an actuator; a compensator advancing the phase of the drive signal to provide a negative feedback signal; and a subtractor providing a differential signal between the drive waveform signal and the negative feedback signal as an input signal to the modulator. The liquid ejection device can be used as a liquid ejection surgical instrument.

Abstract: Disclosed is a liquid ejecting apparatus, and a method of controlling the liquid ejecting apparatus, whereby at a timing at which temperature detection and ejection pulse change are subsequently performed, a frequency of execution of temperature detection and driving pulse change differs according to whether temperature detected by the temperature sensor is in a first temperature range in which a degree of change in viscosity of ink for change in temperature is relatively high or in a second temperature range in which the degree of the change in viscosity for the change in temperature is relative stable. More specifically, in the first temperature range, the frequency of execution of temperature detection and driving pulse change is high compared to the second temperature range.

Abstract: A method of printing using an electrohydrodynamic printing system includes providing an electrohydrodynamic printing system. The electrohydrodynamic printing system includes a nozzle that dispenses a printing fluid and a substrate that receives the printing fluid. The nozzle includes a conductive portion. A voltage source applies a voltage differential between the conductive portion of the nozzle and the substrate. A controller is configured to control the voltage source such that the printing fluid is deposited on the substrate. The method includes causing a drop of the printing fluid to be formed from the conductive nozzle by using the controller to provide a burst mode waveform to the voltage source.

Abstract: An electrohydrodynamic printing system includes a nozzle that dispenses a printing fluid and a substrate support. The nozzle includes a conductive portion. A voltage source applies a voltage differential between the conductive portion of the nozzle and the substrate support. A controller is configured to provide a burst mode waveform to the voltage source such that a drop of the printing fluid is caused to form from the conductive nozzle and travel toward the substrate support.

Abstract: Disclosed is a driving device of a liquid-jet head having a piezoelectric device arranged for each of nozzles and having mutually facing electrodes. The driving device includes switching devices connected in parallel to each other, one of the electrodes being connected to first ends of the switching devices for selectively ON/OFF controlling the switching devices while the other electrode is connected to a reference potential, a driving signal source to generate a driving signal connected to second ends of the switching devices, and a control unit to switch the driving signal to ON or OFF control the switching devices. At least one of the switching devices has electrically conducting properties for not ejecting a liquid drop from the nozzle with a driving signal being applied to the switching device in an ON-controlled status, and the switching devices are all ON-controlled for causing the nozzles to eject liquid drops.

Abstract: An ink is ultra-permeation ink which has a surface tension in a range of 25 mN/m or greater and 35 mN/m or less, and a printer is capable of switching between a single-pass mode in which a specific landing pattern is formed on the recording paper by scan performed once and a multi-pass mode in which the specific landing pattern is formed on the landing target by scan performed a plurality of times. A controller performs control such that a total amount of ink which lands on a region in which the specific landing pattern is formed is relatively great in a case of the single-pass mode compared to a case of the multi-pass mode.

Abstract: A pulse generator forms, from setting data respectively stored in an ejection relevant waveform setting register and a first high impedance setting register, an ejection relevant driving pulse for setting an electrode of an ink chamber communicating with an ejection relevant nozzle to a high impedance state for a predetermined period. The pulse generator forms, from setting data respectively stored in an ejection both-side waveform setting register and a second high impedance setting register, an ejection both-side driving pulse for setting electrodes of ink chambers communicating with ejection both-side nozzles to the high impedance state for the predetermined period. The pulse generator outputs signals of the formed driving pulses to an inkjet head.

Abstract: Among other things, an inkjet print head module includes inkjets from which ink drops are to be jetted during a series of jetting cycles. There is circuitry on the inkjet print head module to (a) form, from trimming information or other information that characterizes jetting waveforms to be applied to respective inkjets in respective jetting cycles, corresponding jetting waveforms and (b) apply the formed jetting waveforms to the respective inkjets in the respective jetting cycles.

Abstract: A device for driving a recording head comprises select data input elements, a waveform signal selector, and a drive signal supplier. To the select data input elements, select data sets corresponding to recording elements included in the recording head are inputted in a serial manner. Each one of the select data sets indicates which one among waveform signals is to be employed for a corresponding recording element in a single printing cycle. The waveform signal selector selects, for each of the recording elements, one among the waveform signals on the basis of a corresponding one among the select data sets inputted to the select data input. The drive signal supplier supplies, based on the selected waveform signal, a drive signal to each of the recording elements. The number of the select data input elements is greater than the number of bits included in each of the select data sets.

Abstract: A droplet discharging device including a discharging hole to discharge droplets, a piezoelectric element that deforms with electrical charging and discharging to discharge droplets therefrom, a piezoelectric element drive circuit that drives the piezoelectric element to cause it to charge and discharge, wherein the piezoelectric element drive circuit has a control signal generating unit to generate control signals that control outputs of drive signals applied to the piezoelectric circuit and a drive signal output unit to output the drive signals applied to the piezoelectric element based on the control signals, wherein the drive signal output unit includes a first field effect transistor that operates to supply an electric current to the piezoelectric element based on the control signals when charging the piezoelectric element and a second field effect transistor that operates to discharge an electric current from the piezoelectric element based on the control signals when discharging the piezoelectric elemen

Abstract: A liquid ejecting apparatus includes a correction section maintains a predetermined voltage range in which a displacement is greater than a predetermined ratio as a drive voltage range from a relationship between each voltage and the displacement when a reference waveform having a process that changes the voltage from a first voltage to a second voltage having a voltage difference and a process that changes the voltage from the second voltage to the first voltage is supplied by making the voltage difference between the first voltage and the second voltage constant and changing the first voltage and the second voltage, and wherein the correction section changes the drive waveform into a drive waveform having a minimum voltage and a maximum voltage defined within the drive voltage range.

Abstract: An ink jet recording apparatus includes a liquid-ejecting head including a pressure-generating chamber filled with a photocurable ink composition containing a polymerizable functional group-containing compound and water, a nozzle communicating with the pressure-generating chamber and ejecting a droplet of the photocurable ink composition, and a pressure-generating member causing a pressure change in the pressure-generating chamber; and an ejection pulse-generating unit generating an ejection pulse for driving the pressure-generating member.

Abstract: Described herein is a method, apparatus, and system 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 first subset of a multi-pulse waveform to the actuator to cause the droplet ejection device to eject a first droplet of a fluid in response to the first subset. The method includes applying a second subset of the multi-pulse waveform to the actuator to cause the droplet ejection device to eject a second droplet of the fluid in response to the second subset. The first subset includes a drive pulse that is positioned in time near a beginning of a clock cycle of the first subset. The first droplet has a smaller volume than the second droplet.

Abstract: A method for operating an inkjet printer includes identifying a pattern of ink drops ejected from an inkjet with reference to image data for a printed image, identifying a waveform component for an electrical signal operating the inkjet to eject an ink drop in the pattern of ink drops with reference to at least a portion of the image data, and generating the electrical signal with the identified waveform component to eject the ink drop in the pattern of ink drops at a first velocity onto a first location of an image receiving surface.

Abstract: A CPU serving as a counting unit counts the cumulative number of times a driving pulse is applied to a piezoelectric vibrator. A driving signal generation unit is able to generate an aging driving pulse set by a driving parameter to the extent that ink is not ejected from a nozzle and performs an aging process of driving the piezoelectric vibrator using the aging driving pulse set by a driving parameter in accordance with a cumulative number of applications in a region outside an ejection region on a recording medium.

Abstract: In an inkjet printer, for forming a large dot on a recording paper in the course of image recording, a second ejection pulse (721) and a first ejection pulse (713) are selected from a basic waveform (70), as a driving signal. For forming a medium dot, a first minute pulse (711) and the first ejection pulse (713) are selected. For forming a small dot, a third ejection pulse (722) is selected. At the time of non-ejection, a second minute pulse (712) is selected. As a result, by adjusting the waveform of the first minute pulse (711), it is possible to form high-quality dots of respective sizes while shortening a driving cycle with the use of the first ejection pulse (713) for forming a large dot and a medium dot.

Abstract: An inkjet recording method is performed using an inkjet recording device including a recording head provided with a nozzle, a pressure chamber, a pressure generator and a driving signal generator, the method satisfying the following requirements (1) and (2): (1) it is required to use aqueous ink having a dynamic surface tension larger by 10 mN/m or more than a static surface tension when the surface life measured at 25° C. by a maximum foaming pressure method is 15 ms and a dynamic surface tension larger by 5 mN/m or more than a static surface tension when the surface life measured by a maximum foaming pressure method is 1500 ms and (2) it is required that the signals have a drawing pulse in one print period and a meniscus of the aqueous ink is drawn into the nozzle in two stages by the drawing pulse.

Abstract: A liquid ejecting apparatus includes a reference drive signal generation section that generates a reference drive signal, a signal modulation section that modulates the reference drive signal to generate a modulation reference drive signal, a signal amplification section that amplifies the modulation reference drive signal using switching elements to generate a modulation drive signal, a signal conversion section that converts the modulation drive signal to a drive signal, and a head which includes a piezoelectric element that deforms in response to the drive signal, a pressure chamber that expands and contracts due to the deformation of the piezoelectric element and has a Helmholtz resonance frequency of a period Tc, and a nozzle opening portion that communicates with the pressure chamber. A period of an alternating current component contained in the modulation drive signal is a divisor of a section of one of the drive signal.

Abstract: A fluid ejection device includes: a modulator adapted to pulse-modulate a drive waveform signal forming a basis of a drive signal of an actuator to obtain a modulated signal; a digital power amplifier circuit adapted to power-amplify the modulated signal to obtain a power-amplified modulated signal; a low pass filter adapted to smooth the power-amplified modulated signal to obtain the drive signal; and a power amplification stopping section operating when holding a voltage of the actuator constant.

Abstract: A liquid ejecting apparatus includes a pressure generation unit that causes a liquid to be ejected from a nozzle opening that communicates with a flow channel and a liquid holding unit that supplies a liquid to the flow channel, and the pressure generation unit performs microvibration driving when the liquid holding unit is replaced.

Abstract: The liquid ejection apparatus includes a liquid ejection head, a drive unit, a non-ejection drive controller, and an environment measurement unit. The drive unit selectively supplies an ejection drive signal and a non-ejection drive signal to the actuator. The non-ejection drive controller causes the drive unit to supply the non-ejection drive signal to the actuator within a non-ejection drive period which is at the trailing end portion of the non-ejection period, when the non-ejection period satisfies the predetermined condition. The non-ejection drive controller controls the drive unit so that the length of a blank period is varied based on at least one of the temperature and the humidity measured by the environment measurement unit, the blank period being a period between a point of supplying a final non-ejection drive signal within the non-ejection drive period and the trailing end of the non-ejection period.

Abstract: A circuit device drives actuator elements respectively associated with a plurality of nozzles to cause droplets to be ejected from the nozzles. The circuit device includes input terminals; a receiving unit; a switching unit; and a transfer unit. The receiving unit receives, via the input terminals, input signals including a terminal arrangement signal and drive signals for driving the actuator elements. The terminal arrangement signal indicates a type of assignment of signals to be assigned to the input terminals. The switching unit switches the assignment of signals in accordance with the terminal arrangement signal. The transfer unit transfers, to the actuator elements, drive signals that are input to the input terminals after the assignment of signals has been switched.

Abstract: According to the present invention, the occurrence of an ejection abnormality can be determined at an early stage by using a waveform for abnormal nozzle determination, before an image defect producing a visible density non-uniformity (stripe non-uniformity) occurs due to an ejection defect in an output image recorded by a drive signal having a recording waveform. Consequently, recording stability and throughput can both be achieved.

Abstract: An inkjet recording apparatus includes: an inkjet head which has a nozzle and an ejection energy generating element configured to cause droplets to be ejected from an ejection port of the nozzle; a head movement device which is configured to reciprocally move the inkjet head to scan a recording medium onto which the droplets ejected from the inkjet head are deposited; a linear encoder which is configured to output signals to determine a position of the inkjet head; an ejection trigger signal generating device which is configured to generate ejection trigger signals in accordance with the output signals of the linear encoder, the ejection trigger signals specifying ejection timings of the inkjet head with a temporal resolution of 0.1 ?s order; and an ejection control device which is configured to cause the inkjet head to eject the droplets in accordance with the ejection timings specified by the ejection trigger signals.

Abstract: A waveform amplifier for a piezoelectric liquid ejection element. The amplifier provides an amplified waveform to the liquid ejection element.

Abstract: An inkjet recording device includes a recording head, a head driving unit, and a controller. A selector of the head driving unit performs selection for individual nozzles so that when the drive waveform selection data for printing one line at this time sent from a data processing section indicates that the number of times of ink ejection is 0, and drive waveform selection data for printing the next one line indicates that the number of times of ink ejection is 0, drive voltage according to none of one or more drive waveforms for ink ejection or a drive waveform for meniscus oscillation is applied to a piezoelectric element.

Abstract: An inkjet recording apparatus comprises an inkjet recording head configured to eject an ink droplet from a nozzle by utilizing micro vibrations of a piezoelectric element; and a recording-head driving circuit configured to apply a drive voltage to the piezoelectric element. And, in the apparatus, the recording-head driving circuit includes a D/A converter configured to generate an analog voltage from and corresponding to digital data input to the D/A converter, and a reference-voltage generating circuit configured to generate a reference voltage of the D/A converter, and the reference-voltage generating circuit is configured to be capable of controlling a manner in which the reference voltage falls when an anomaly occurs to the inkjet recording apparatus.

Abstract: In a method to execute a print interruption, a printing substrate is printed to with a printing unit with at least one print head. With aid of a sensor, print clock pulses are generated that are supplied to a print controller depending on a feed of the printing substrate. With triggering of the print interruption, a feed speed of the printing substrate is reduced from a print speed in the printing operation to a predetermined speed according to a deceleration ramp. After the print interruption the printing substrate is accelerated again to the print speed according to an acceleration ramp. Given occurrence of a print clock pulse during at least one of the ramps, the print controller sends at least one vibration pulse to the at least one print head so that at least one cycle of vibration oscillations is implemented at the print head. The at least one vibration pulse is generated if a time interval of the print clock pulses relative to one another reaches a predetermined value.

Abstract: A nozzle discharge quantity correction method includes performing correction quantity calculation as the number of the nozzle array units in stages such that a total sum C of the weight of droplets in nozzle array units after correction and the weight of the droplets in other nozzle array units in which discharge is performed on the discharge region becomes a previously set predetermined quantity B based on the difference between the total sum A of the weight of all the droplets discharged to a discharge region when the weight of the droplets discharged from a nozzle are not corrected and the predetermined quantity B.

Abstract: A control circuit for a drop-on-demand piezoelectric fluid-ejection mechanism includes a drive and sense circuit, and a switch. The drive and sense circuit has an input, a drive output, and a sense output. The drive output is to be coupled to the drop-on-demand piezoelectric fluid-ejection mechanism. The switch is to switch the input of the drive and sense circuit between a feed-forward driving mode of the drive and sense circuit and a feedback damping mode of the drive and sense circuit. In the feed-forward driving mode, the switch is to couple the input to a drive waveform to cause the fluid-ejection mechanism to eject a drop of fluid. In the feedback damping mode, the switch is to couple the input to the sense output to dampen the fluid-ejection mechanism after the fluid-ejection mechanism has ejected the drop of fluid.