A head unit includes a piezoelectric element displaced according to a driving signal to cause a liquid to be ejected, a driving signal generation unit that generates the driving signal, a residual vibration signal generation circuit that outputs a change in an electromotive force of the piezoelectric element according to residual vibration, in a pressure chamber in communication with a nozzle, that occurs after supply of the driving signal, as a residual vibration signal, an analog differential residual vibration signal generation circuit that converts the residual vibration signal into an analog differential residual vibration signal, a demodulation circuit that demodulates the analog differential residual vibration signal and outputs a demodulated signal, an AD converter that converts the demodulated signal into a digital signal, and a determination unit that determines, based on the digital signal, a state in the pressure chamber.

A liquid discharge head includes: a discharge port, from which a liquid is to be discharged; and an openably closing valve configured to move in a moving direction toward the discharge port to openably close the discharge port, the openably closing valve including a core, wherein the core has a core end at one end of the core opposing the discharge port, the core end has: a concave in the core end, the concave recessed in a direction opposite to the discharge port; and an elastic member covering the concave and an outer side face of the core end continuously.

The inkjet recording apparatus includes a recording head, a cap member, a humidifying part for humidifying interior of the cap member, a cap moving mechanism, a controller, and a storage part. The storage part has stored a non-capping period table in which a number of vibrations of ink level within each nozzle is increased based on a non-capping period of an ink ejection surface, and a capping period table in which the number of vibrations is decreased based on a capping period of the ink ejection surface. In response to respective lengths of the non-capping period and the capping period from an end of ink ejection until a start of next ink ejection, the controller sets the number of vibrations at a start time of next ink ejection by using the non-capping period table and the capping period table.

The inkjet recording apparatus includes a recording head, a cap member, a humidifying part for humidifying interior of the cap member, a cap moving mechanism, a controller, and a storage part. The storage part has stored a non-capping period table in which a number of vibrations of ink level within each nozzle is increased based on a non-capping period of an ink ejection surface, and a capping period table in which the number of vibrations is decreased based on a capping period of the ink ejection surface. In response to respective lengths of the non-capping period and the capping period from an end of ink ejection until a start of next ink ejection, the controller sets the number of vibrations at a start time of next ink ejection by using the non-capping period table and the capping period table.