Provided is an inkjet head containing a nozzle plate having at least a substrate, wherein the nozzle plate has a liquid-repellent layer on an outermost surface of the substrate on an ink ejection surface side; a liquid-repellent layer base film is provided between the substrate and the liquid-repellent layer; and the liquid-repellent layer base film contains at least silicon (Si) and carbon (C), and having a maximum peak P of a binding energy of a Si2p orbital of a surface portion measured by X-ray photoelectron spectroscopy is in the range represented by the following Formula (1), Formula (1): 99.6 (eV)≤P≤101.9 (eV).

A piezoelectric actuator comprises a vibration plate, a first electrode, a first piezoelectric layer, a second electrode, a second piezoelectric layer and a third electrode. With respect to a top-bottom direction orthogonal to a surface of the vibration plate, the vibration plate, the first electrode, the first piezoelectric layer, the second electrode, the second piezoelectric layer and the third electrode are stacked in this order. The second piezoelectric layer is narrower than the first piezoelectric layer in a first direction parallel to the surface of the vibration plate. The third electrode extends in the first direction and covers both side surfaces of both of the first piezoelectric layer and the second piezoelectric layer in the first direction.

A liquid discharge head includes a piezoelectric element, a first holding substrate, a second holding substrate, and damper. The first holding substrate has a recess accommodating the piezoelectric element, a first partition having a first width in a width direction of the first partition, and first side spaces partitioned by the first partition. The second holding substrate has a second partition having a second width wider than the first width in the width direction and second side spaces partitioned by the second partition. The damper is disposed between the first holding substrate and the second holding substrate. The damper has a first surface facing the first holding substrate, a second surface opposite to the first surface, and a penetrating portion penetrating through the damper. The second surface is bonded to the second partition of the second holding substrate. The penetrating portion is disposed adjacent to the second partition.

A piezoelectric element has a diaphragm, a first electrode on the diaphragm, a piezoelectric layer on the first electrode, and a second electrode on the piezoelectric layer. The piezoelectric layer is a stack of multiple piezoelectric films and is made of a perovskite composite oxide containing lead, zirconium, and titanium and represented by the general formula ABO.sub.3, with the molar ratio of the A-site to the B-site (A/B) in the perovskite composite oxide being 1.14 or more and 1.22 or less. In current-time curve measurement, the activation energy calculated from relaxation current using an Arrhenius plot is 0.6 [eV] or less. The relaxation current is the amount of current at the time at which a downward trend in current turns upward.

An apparatus includes a reservoir and a printhead. The printhead includes a support structure including a deformable portion defining at least a top surface of a pumping chamber, a flow path extending from the reservoir to the pumping chamber to transfer fluid from the reservoir to the pumping chamber, and an actuator disposed on the deformable portion of the support structure. A trench is defined in a top surface of the actuator. Application of a voltage to the actuator causes the actuator to deform along the trench, thereby causing deformation of the deformable portion of the support structure to eject a drop of fluid from the pumping chamber.

There is provided a liquid discharge head, including: a piezoelectric body having a plurality of piezoelectric layers stacked on top of each other in a stacking direction; individual electrodes; and a first common electrode. Each of the individual electrodes has a first portion and a second portion arranged in the first direction at an interval, and a third portion coupling the first portion with the second portion. The first common electrode includes a first extending portion as well as first protrusions and second protrusions protruding from the first extending portion. Portions of the first extending portion overlapping in the stacking direction with the third portions are formed having through holes passing through the first common electrode in the stacking direction.

A liquid ejecting head including a diaphragm constituting a portion of a wall surface of a pressure chamber that accommodates a liquid, and a piezoelectric element that vibrates the diaphragm. In the liquid ejecting head, the diaphragm includes a plurality of layers, and d/D0.25 is satisfied where D is a thickness of the diaphragm and d is a distance between a neutral axis of the diaphragm and an interface between two adjacent layers in which a tension difference is the largest in the plurality of layers.

A piezoelectric element includes an upper electrode, a lower electrode, and a piezoelectric body disposed between the upper electrode and the lower electrode. The piezoelectic body contains lead zirconate titanate. The piezoelectric element also includes a seed layer containing lead disposed between the lower electrode and the piezoelectric body. The seed layer has an amorphous structure at least over an entire surface layer portion on the piezoelectric body side.

A printhead module includes a plurality of rows of printhead nozzles, at least some of the rows including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed, wherein the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

A liquid discharge head includes first and second actuators and a drive circuit. Each of the first and second actuators is configured to expand and contract first and second pressure chambers, respectively. The drive circuit is configured to, during a dot formation cycle apply a first number of discharge pulses to the first actuator to cause the first number of droplets to be discharged from the first pressure chamber and apply a second number of discharge pulses to the second actuator to cause the second number of droplets to be discharged from the second pressure chamber and apply a third number of precursors to the second actuator. The first number is greater than or equal to two. Each of the second and third numbers is greater than or equal to one. A sum of the second and third numbers is less than or equal to the first number.