An inkjet head includes: a pressure chamber filled with ink; an actuator that changes a pressure of the ink filling the chamber; a nozzle that ejects the ink filling the chamber by the actuator being driven; and a communication channel that supplies the ink to the chamber. The communication channel has a narrowed part having a cross-sectional area perpendicular to an ejection direction of the ink smaller than any other part in the communication channel. Q.sub.C that is a Q factor in the chamber calculated by using 5.7 mPa.Math.s as a viscosity of the ink, 1,080 kg/m.sup.3 as a density of the ink, and 1,521 m/s as a value of a speed of a sound transmitted through the ink satisfies Formula (1); Q.sub.C0.0222S.sub.r17.524, where S.sub.r represents, of the narrowed part, the cross-sectional area perpendicular to the ejection direction of the ink.

A liquid jet head and so on capable of easily improving ejection stability of a liquid are provided. A liquid jet head according to an embodiment of the present disclosure includes a jet unit including a plurality of nozzles configured to jet a liquid, and a plurality of pressure chambers communicated individually with the nozzles, and each filled with the liquid, and a drive unit configured to drive the jet unit based on a drive signal having a plurality of pulses in a predetermined print period to thereby jet the liquid which fills an inside of the pressure chamber from the nozzle. The plurality of pulses in the drive signal includes one ejection pulse or a plurality of ejection pulses having a pulse width in a range in which the liquid is ejected from the nozzle, and one heat generation pulse or a plurality of heat generation pulses which has a pulse width in a range in which the liquid is not ejected from the nozzle, and which is configured to control a heat generation amount generated when the jet unit is driven.

A technique capable of appropriately detecting a timing for replacement of a liquid ejection head is provided. The liquid ejection head includes a first electrode configured to protect an electrothermal conversion element that ejects a liquid from an ejection port and to be capable of eluting into the liquid by an electrochemical reaction with the liquid; and a second electrode installed so as to be electrically connectable to the first electrode via the liquid. A voltage is applied to cause the second electrode to generate the electrochemical reaction with the first electrode so that the first electrode is eluted into the liquid. Polarities can be reversed between the first electrode and the second electrode for applying the voltage, and wiring resistance in a circuit including a plurality of second electrodes as a part of wiring can be measured.

A liquid ejecting head includes a nozzle, first and second pressure chambers communicating with the nozzle, a first driving element configured to change a pressure in the first pressure chamber, and a second driving element configured to change a pressure in the second pressure chamber. A first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. In a driving method of a liquid ejecting head, at least the first and second driving elements are driven to eject a liquid from the nozzle, and a driving timing of the second driving element is earlier than a driving timing of the first driving element.

In a liquid ejecting apparatus, a drive signal includes a plurality of ejection pulses corresponding to a plurality of droplets that are combined before landing on a medium. The plurality of ejection pulses has filling elements and ejection elements. The ejection element of a first ejection pulse changes in electrical potential from a first electrical potential to a reference electrical potential. The ejection element of the last ejection pulse changes in electrical potential from a second electrical potential to a third electrical potential. The reference electrical potential is between the first electrical potential and the third electrical potential and between the second electrical potential and the third electrical potential. A time period from the start of the filling element of the last ejection pulse to the start of the ejection element of the last ejection pulse is greater than or equal to 0.5 TC and less than 0.7 TC.

An inkjet printer includes a drive signal generation unit configured to generate a drive signal, a discharge section including a nozzle, a piezoelectric element driven by the drive signal, and a cavity configured to discharge ink from the nozzle according to the driving of the piezoelectric element, a first inspection signal generation circuit configured to receive input of a residual vibration signal generated according to vibration remaining in the discharge section after the piezoelectric element is driven and generate a pseudo residual vibration signal corresponding to the residual vibration signal; and an inspection unit configured to determine a state of the discharge section based on the pseudo residual vibration signal. The first inspection signal generation circuit generates the pseudo residual vibration signal to imitate an attenuation wave of the residual vibration signal and outputs the generated pseudo residual vibration signal.

There is provided a droplet ejecting apparatus including: a head having a nozzle, a channel, and an actuator; a driving circuit; a mover; and a controller. The controller is configured to execute a moving process of causing the mover to move the head and the recording medium, and an ejecting process of causing the driving circuit to supply a driving signal to the actuator. The driving signal includes a first driving signal to cause the actuator to eject the droplet of a first volume, and a second driving signal to cause the actuator to eject the droplet of a second volume different from the first volume, a resolution of the second driving signal being higher than a resolution of the first driving signal. The controller is configured to, in the ejecting process based on one recording instruction, cause the driving circuit to supply the first or second driving signal.

A signal generation device includes a first signal generation portion and a second signal generation portion. The first signal generation portion, based on a reference signal that includes a plurality of rectangular single-wave signals, generates an original common signal in which the rise times of the two or more of the single-wave signals are extended so that they are different from each other, and the fall timing of one or more of the single-wave signals is shifted. The second signal generating portion generates a drive signal to be input to a piezoelectric element by extracting a rising edge of any one of the single-wave signals, the rise time of which is extended, from the original common signal amplified by the amplifying portion, maintaining a signal level changed by extracting the rising edge of the single-wave signal, and extracting a falling edge of a single-wave signal after the single-wave signal.

A liquid discharge apparatus includes a nozzle plate (101), a valve (131), a driver (132), and circuitry (500). The nozzle plate has a nozzle hole (102) from which a liquid is dischargeable. The valve openably closes the nozzle hole. The driver moves the valve to openably close the nozzle hole. The circuitry applies a first drive signal having a first drive period to the driver to open the nozzle hole for a first valve opening time equal to or shorter than the first drive period in a first drive period band and applies a second drive signal having a second drive period to the driver to open the nozzle hole for a second valve opening time shorter than the first valve opening time. The second valve opening time is longer than the second drive period in a second drive period band.

The present disclosure relates to a drive system for a row-connected inkjet apparatus. The system comprises a main control board, a plurality of drive boards, corresponding groups of printing heads, synchronization modules, and communication modules. The main control board sends printing time-sequence synchronization information to each drive board via the synchronization modules and sends printing data via the communication modules. Each printing-head group responds to the drive signal from its corresponding drive board and simultaneously performs jet printing of its assigned portion of the data, thereby enabling rapid spliced printing. This configuration offers broad utility in achieving efficient and precise spliced printing.