An inkjet recording head comprising a flow channel member, wherein the flow channel member is formed of a heat-cured product of a molding material comprising a resin composition comprising a thermosetting epoxy resin and a curing agent, and a filler; the filler comprises alumina and silica; and with d50 as a median diameter of the silica and with alumina A as the alumina having a median diameter of d50/4 or less, the content of the alumina A is 11 parts by mass or more relative to 100 parts by mass of the silica.

An electric current based on electric charge produced on the piezoelectric body changes by going through a first path, a second path, a third path, and a fourth path in this order. On the first path, the electric current becomes larger as the voltage becomes higher. On the second path, the electric current becomes smaller as the voltage becomes higher. On the third path, the electric current becomes larger as the voltage becomes higher. On the fourth path, the electric current becomes smaller as the voltage becomes higher.

A microfluidic device has a chamber; a fluidic access channel in fluidic connection with the chamber; a plurality of nozzle apertures in fluidic connection with the chamber; and an actuator, operatively coupled to the fluid containment chamber and configured to cause ejection of drops of fluid through the nozzle apertures in an operating condition of the microfluidic device. The chamber has an elongated shape, with a length and a maximum width, wherein an aspect ratio between the length and the maximum width of the chamber is at least 3:1. The nozzle apertures are configured to generate, in use, a plurality of drops having a total drop volume, wherein a ratio total drop volume to a chamber volume is at least 15%.

A method of manufacturing a liquid discharge head includes preparing a first substrate where a discharge port configured to discharge liquid is formed to face a first surface, a concave portion is formed on a side of a second surface opposite to the first surface, and a first liquid flow passage penetrating from the first surface to the second surface is opened inside the concave portion on the side of the second surface, preparing a second substrate including a second liquid flow passage opened on a third surface, and sticking the first substrate and the second substrate to communicate the first liquid flow passage with the second liquid flow passage by bonding a bottom face of the concave portion and the third surface with an adhesive agent.

A substrate with an electrical connection section or a substrate for liquid ejection head comprises a wiring layer, a diffusion prevention layer laid on the wiring layer and a connection member laid on the diffusion prevention layer for establishing an electrical connection to an outside. An insulation layer having a wiring-layer-exposing opening is arranged on the wiring layer and the diffusion prevention layer is arranged in the opening, while the connection member is arranged on the diffusion prevention layer so as to cover an outer peripheral edge of the diffusion prevention layer.

An actuator includes a substrate, a diaphragm on the substrate, a lower electrode on the diaphragm, a piezoelectric body on the lower electrode, and an upper electrode on the piezoelectric body. A ratio of lead (Pb) and zirconium (Zr) in atomic percent (atm %) present at a grain boundary in the piezoelectric body satisfies a relation of Pb/Zr>1.7.

Disclosed is a method of manufacturing, a metal nozzle plate, in which is formed a nozzle for discharging a liquid and that is to be bonded with adhesive to a head chip provided with an actuator for discharging the liquid, the method including: forming the nozzle in a metal plate-like member; forming a groove in the metal plate-like member; and performing exterior processing with respect to the nozzle plate.

A flow path member includes a first substrate having a first surface that has a flow path, and includes a second substrate having a second surface opposing the first surface. In the flow path member in which the first and second substrates are joined together with adhesive provided between the first and second surfaces, a groove is formed in at least one of the first and second surfaces. When the first substrate is viewed from a direction orthogonal to the first surface, the flow path is disposed on a groove inner side. The groove has a first portion having a first depth and a second portion having a second depth shallower than the first depth. The second portion is that portion of the groove existing inside a region surrounded by an outer edge of the first surface and extension lines of two sides that form a flow path corner.

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.