A liquid ejecting head includes: a pressure chamber substrate; and a communication plate, in which the pressure chamber substrate includes a first pressure chamber that extends in a first direction and applies pressure to a liquid, and a first supply channel, and the communication plate includes a first communication channel that extends in a second direction intersecting with the first direction and communicates with the first supply channel, and a second supply channel that communicates with the first supply channel and the first pressure chamber.

S1 is a sum of the areas of a plurality of individual electrodes formed on a first plane of a piezoelectric body of a liquid discharge head, S2 is an area of a first common electrode formed on a second plane, S3 is an area of a second common electrode formed on a third plane, D1 is a distance between a neutral plane and the first plane in a stacking direction, D2 is the distance between the neutral plane and the second plane in the stacking direction, and D3 is the distance between the neutral plane and the third plane in the stacking direction. Then, D1×S1+D2×S2>D3×S3 is satisfied. The liquid discharge head includes a plurality of conductor layers which are formed on the third plane, without contact with the second common electrode and without contact with each other.

A head module includes a pressure chamber, a piezoelectric member, a supply manifold, a return manifold, and a damper portion. The pressure chamber is configured to hold liquid therein and in fluid communication with a nozzle orifice. The piezoelectric member is configured to apply pressure to liquid held in the pressure chamber. The supply manifold is in fluid communication with the pressure chamber and configured to allow liquid to flow into the pressure chamber therefrom. The return manifold is in fluid communication with the pressure chamber and configured to allow liquid not ejected from the nozzle orifice to flow thereinto. The damper portion is positioned between the supply manifold and the return manifold when viewed in plan from a nozzle surface of the head module. The nozzle surface has the nozzle orifice defined therein. The damper portion includes a particular plate having a particular recessed portion.

The individual flow path includes a nozzle communicating with an outside, a first flow path, in the middle of which the nozzle is disposed and which extends in a first direction that is an in-plane direction of a nozzle surface of the nozzle plate in which the nozzle opens, a second flow path coupled to the first flow path and extending in a second direction other than the first direction, a third flow path coupled to the second flow path and extending in the third direction other than the second direction, and a pressure chamber which is disposed in the third flow path and in which a pressure change is induced by the energy generating element. A cross-sectional area of the first flow path is smaller than a cross-sectional area of the second flow path.

A MEMS device includes a first substrate 22 including a single-crystal silicon substrate and a second substrate 23 including a single-crystal silicon substrate, in which the first substrate 22 and the second substrate 23 are laminated together, and the first substrate 22 and the second substrate 23 are joined to each other such that the cleavage directions of both substrates intersect each other.

A liquid ejection head with which print of good print quality can be obtained and a method of manufacturing the liquid ejection head are provided. For that purpose, warped flow path members are joined to each other as flow path members used for a print head to form a flow path member warped in a direction opposite to a direction of warpage due to a temperature rise during printing.

A liquid discharge head includes a flow channel member, a pressurization part, a plurality of discharge holes, a flexible substrate, a cover member, and a heater. The flow channel member includes a first surface and a second surface that is positioned on an opposite side of the first surface. The pressurization part is positioned on the first surface. The plurality of discharge holes are positioned on the second surface. For the flexible substrate, a one-end part thereof that is positioned on the pressurization part is electrically connected to the pressurization part. The cover member covers the one-end part of the flexible substrate. The heater is positioned on the cover member.

There is provided a liquid discharge head including a piezoelectric body having a plurality of individual electrodes and a first common electrode, and a plurality of conductor layers. The plurality of individual electrodes have first to fourth individual electrode arrays, and the first common electrode has first and second extending portions, a plurality of first projecting portions, and a plurality of second projecting portions. Each of the first projecting portions overlaps partially with one of the plurality of individual electrodes forming the second individual electrode array along the stacking direction, and each of the second projecting portions overlaps partially with one of the plurality of individual electrodes forming the third individual electrode array along the stacking direction. The plurality of conductor layers are formed between the plurality of first projecting portions and the plurality of second projecting portions, without contacting the first common electrode and without contacting each other.

A liquid droplet discharge head includes a reservoir having a slit portion through which a flexible substrate is extracted outward. A closing member is disposed in the slit portion, and a sealing resin is disposed on the closing member.

Provided are a liquid jetting structure and its applications. The liquid jetting structure includes: a nozzle substrate on which a nozzle for jetting a liquid is formed; and a flow passage substrate on which a liquid flow passage communicating with the nozzle is formed, in which a first layer, a second layer, and a liquid-repellent layer are provided in this order on a jetting surface of the nozzle substrate, the first layer and the second layer are provided in this order on an inner wall of the liquid flow passage, the first layer is a layer containing at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide, and the second layer is a layer containing at least one selected from the group consisting of SiO.sub.2, SiC, SiN, SiCN, and SiON.