A piezoelectric device includes a substrate, a diaphragm; and a piezoelectric actuator, in which the substrate, the diaphragm, and the piezoelectric actuator are laminated in this order in a first direction, the diaphragm includes a first layer containing silicon as a constituent element, a third layer disposed between the first layer and the piezoelectric actuator and containing zirconium as a constituent element, and a second layer disposed between the first layer and the third layer and containing at least one impurity element selected from the group consisting of a metal, a metalloid, and a semiconductor other than silicon and zirconium, as a constituent element, and the impurity element diffuses into the third layer.

The diaphragm includes a first layer containing silicon as a constituent element, a third layer disposed between the first layer and the piezoelectric actuator and containing zirconium as a constituent element, and a second layer disposed between the first layer and the third layer and containing at least one selected from the group consisting of a metal other than iron, silicon, and zirconium, a metalloid, and a semiconductor, as a constituent element, in the second layer and the third layer, a position with a highest concentration of impurities other than the constituent elements of the second layer and the third layer is in the second layer, a position with a highest concentration of zirconium is in the third layer, and a position with a highest concentration of silicon is in the first layer.

A control board connectable to a liquid ejection head includes a power supply circuit outputting a first voltage, a connector connectable to a cable through which the first voltage is input and a second voltage is output, and a processor detecting a connection error of the cable using a difference between the first and second voltages, and control the circuit to turn off upon detection of the error. The connector includes first, second, and third terminals adjacent to each other and arranged along a direction in this order and fourth, fifth, and sixth terminals adjacent to each other and arranged along the first direction in this order. The first voltage is input to the second terminal, the second voltage is output from the fifth terminal, and the first, third, fourth, and sixth terminals are ground terminals. The second and fifth terminals are short-circuited in the liquid ejection head.

A method for producing a liquid transport apparatus is disclosed. The liquid transport apparatus includes a pressure chamber plate, a ceramics layer formed on a surface of the pressure chamber plate, a piezoelectric layer formed on the ceramics layer, and an electrode formed on the piezoelectric layer. The ceramics layer is formed by heating an insulating ceramic material at a temperature lower than an annealing temperature of the piezoelectric layer. Accordingly, the atoms of the pressure chamber plate are suppressed from being diffused into the piezoelectric layer.

A liquid supply device includes a collection sub tank and a collection flow path. The collection sub tank collects liquid from a liquid discharge head. The collection flow path connects the liquid discharge head and the collection sub tank. The collection sub tank includes a first inflow port connected with the collection flow path and a first inner wall portion on an extension line extending from the first inflow port in a direction in which the liquid flows into the collection sub tank from the collection flow path. The first inner wall portion has one of an inclined surface inclined with respect to the extension line, an arc-shaped surface, and a curved surface.

Printheads and manifolds within printheads. In one embodiment, a method comprises determining a resonant frequency of jetting channels for a printhead, and selecting a target length for a manifold fluidly coupled to the jetting channels such that resonant frequencies of the manifold differ from the resonant frequency of the jetting channels by a threshold amount.

A liquid discharge apparatus includes: a liquid discharge head configured to discharge a liquid from a nozzle; a drive waveform generator configured to generate a drive waveform including multiple drive pulses to be applied to the liquid discharge head, the multiple drive pulses successively including: a first drive pulse configured to cause the liquid discharge head to discharge the liquid; a second drive pulse configured to cause the liquid discharge head not to discharged the liquid while causing meniscus of the liquid in the nozzle in the liquid discharge head to vibrate; and a third drive pulse configured to cause the liquid discharge head to discharge the liquid; in time series.

A liquid ejecting head includes a liquid flow channel including nozzles constituting a nozzle row configured to eject a liquid, a dummy flow channel including dummy nozzles constituting a dummy nozzle row not configured to eject liquid, and a closing section formed by an adhesive and closing the dummy flow channel.

A liquid discharge head includes an individual channel which includes: a nozzle; a pressure chamber; a descender of which one end in the first direction is nearer to the nozzle than the other end; and a second connecting channel connecting a second common channel and the one end of the descender. A central axis of the nozzle is positioned between the second common channel and a central axis of the descender in the second direction. The descender includes a first portion including the one end and a second portion positioned between the pressure chamber and the first portion in the first direction. In an end, of the descender, opposite to the second connecting channel in the second direction, an inner wall defining the one end of the first portion protrudes toward the second connecting channel in the second direction beyond an inner wall defining the second portion.

A liquid discharge head that includes piezoelectric elements, a pressure chamber plate defining pressure chambers corresponding to the piezoelectric elements, and a vibrating plate disposed between the piezoelectric elements and the pressure chamber plate is provided. In the liquid discharge head, the vibrating plate has, in a first position and a second position, a first portion and a second portion that is away from the end of the pressure chamber than the first portion in a first direction and has a thickness different from a thickness of the first portion. In the first position, a width of the second portion in the first direction is a first width, and in the second position, a width of the second portion in the first direction is a second width that is less than the first width.