A liquid discharge head includes a nozzle, an individual liquid chamber, a common liquid chamber, a fluid restrictor, a circulation channel, a circulation fluid restrictor, and a plurality of laminated plate members. The nozzle discharges liquid. The individual liquid chamber is communicated with the nozzle. The common liquid chamber supplies the liquid to the individual liquid chamber. The fluid restrictor is disposed between the individual liquid chamber and the common liquid chamber. The circulation channel is communicated with the individual liquid chamber. The circulation fluid restrictor is disposed between the individual liquid chamber and the circulation channel. The plurality of laminated plate members constitutes the fluid restrictor, the individual liquid chamber, and the circulation fluid restrictor. A single plate member of the plurality of laminated plate members defines a fluid resistance value of the fluid restrictor and a fluid resistance value of the circulation fluid restrictor.

A piezoelectric device includes a diaphragm, a piezoelectric actuator, and an orientation layer between the diaphragm and the piezoelectric layer. The piezoelectric actuator has a first electrode, a piezoelectric layer, and a second electrode, with the first electrode, a piezoelectric layer, and a second electrode on the diaphragm. The orientation layer is a stack of two or more tiers.

A liquid discharge head includes a channel member including a common chamber configured to store a liquid; a nozzle plate on one surface of the channel member, and multiple tubular partition walls on another surface of the channel member. The nozzle plate includes multiple nozzles from each of which the liquid is dischargeable in a discharge direction, the multiple tubular partition walls are disposed at positions corresponding to the multiple nozzles, the multiple tubular partition walls define multiple individual chambers respectively communicating with the multiple nozzles in the common chamber, and each of the multiple tubular partition walls includes communication channel through which the liquid is supplied from the common chamber to the multiple individual chambers.

A liquid discharge head includes a head body configured to discharge a liquid, a head cover on the head body, a head cover covering at least a part of the head body, the head cover disposed outside the head body; a liquid supply port on an upper surface of the head cover, the liquid supply port configured to supply the liquid to the head body, an electrical connection on a side surface of the head cover. The head cover includes a protruding part protruding from the upper surface of the head cover, the protruding part is on a side end of the upper surface of the head cover adjacent to the side surface of the head cover on which the electrical connection is disposed, and the protruding part is higher than another part of the upper surface of the head cover with respect to a lower end surface of the head body.

Provided is an ink discharging apparatus configured to discharge an active-energy-ray-curable ink from an ink discharging head of which members to contact the ink are joined using an epoxy adhesive, wherein the ink contains at least any one selected from the group consisting of an acrylamide compound and an N-vinyl compound, and wherein an elastic modulus decreasing rate represented by a formula (1) below is 50 percent or less,

Elastic modulus decreasing rate (%)={(E.sub.1−E.sub.2)/E.sub.1}×100   formula (1)

where E.sub.1 represents an elastic modulus (GPa) of a cured product obtained by curing the epoxy adhesive at 90 degrees C. for 4 hours, and E.sub.2 represents an elastic modulus (GPa) of an immersed product obtained by immersing the cured product in the ink at 60 degrees C. for 4 weeks.

A connection method includes softening a resin film of a thermosetting resin by heating an element electrode of a piezoelectric body and a substrate electrode of a flexible cable to be connected to the piezoelectric body with the element electrode and the substrate electrode being pressed into contact with each other via the resin film; partially pushing out the molten resin film from an opposing position of the element electrode and the substrate electrode so as to bring a solder layer provided on the substrate electrode into contact with the element electrode; curing the resin film and melting solder in the solder layer by further raising a heating temperature; discharging excess solder in a direction defined by the cured resin film; and then solidifying the solder in the solder layer so as to solder the element electrode and the substrate electrode together.

A liquid discharge head includes nozzles, pressure chambers, pressure generators, a common liquid chamber, a partition, and a liquid feeder. The common liquid chamber includes two chamber portions adjacent to each other on a plane parallel to a nozzle array direction. The two chamber portions include a first chamber portion to receive liquid from a supply unit and a second chamber portion to supply liquid to the pressure chambers. The partition includes openings and partitions the first portion from the second portion. The first portion includes at least one liquid inlet at a first end and at least one liquid outlet at a second end opposite the first end in the nozzle array direction. The second portion has a cross-sectional area smaller than a cross-sectional area of the first portion in a cross section of the two chamber portions perpendicular to the nozzle array direction.

Provided is a piezoelectric film formed by a vapor phase growth method, the piezoelectric film containing:

a perovskite oxide in which a perovskite oxide represented by the following formula P is doped with Si in an amount of from 0.2 mol % to less than 0.5 mol %, wherein a ratio of a peak intensity of a pyrochlore phase to a sum of peak intensities in respective plane orientations of (100), (001), (110), (101) and (111) of a perovskite phase measured by an X-ray diffraction method is 0.25 or less:

A.sub.1+δ[(Zr.sub.xTi.sub.1−a).sub.1−aNb.sub.a]O.sub.y  Formula P

wherein, in formula P, A is an A-site element primarily containing Pb; Zr, Ti, and Nb are B-site elements; x is more than 0 but less than 1; a is 0.1 or more but less than 0.3.

A communication plate in which are provided a first communication channel communicating with the first pressure chamber and the second pressure chamber and a first common liquid chamber communicating with the first pressure chamber and the second pressure chamber at positions different from positions at which the first communication channel communicates with the first pressure chamber and the second pressure chamber, and a nozzle substrate in which a first nozzle communicating with the first pressure chamber and the second pressure chamber in common via the first communication channel is provided. A second communication channel communicating with the first common liquid chamber and communicating with the first pressure chamber and the second pressure chamber in common is provided in the pressure chamber substrate or the communication plate.

A liquid discharge head includes a nozzle to discharge a liquid, an individual chamber communicating with the nozzle, a supply channel communicating with the individual chamber to supply the liquid to the individual chamber, and a discharge channel communicating with the individual chamber to discharge the liquid in the individual chamber. A fluid resistance of the supply channel is greater than a fluid resistance of the discharge channel.