There is provided a head module in which a first direction is a main scanning direction, including: a first nozzle row including a first nozzle; a second nozzle row including a second nozzle; and a third nozzle row including a third nozzle, in which a distance P1 between the first nozzle row and the second nozzle row in the first direction and a distance P2 between the first nozzle row and the third nozzle row in the first direction are expressed as P1:P2=E1:O1 where a value E1 is a positive even number and a value O1 is a positive odd number satisfying O1>E1.

A liquid ejecting head including: an individual flow path row in which a plurality of individual flow paths communicating with a nozzle that ejects a liquid in a first axis direction are arranged in parallel along a second axis orthogonal to a first axis, and a first common liquid chamber communicating with the plurality of individual flow paths, in which each of the plurality of individual flow paths has a pressure chamber that stores a liquid.

A liquid ejecting apparatus includes a head unit having heads that configure to eject a liquid in a first-direction, and in which a second-direction orthogonal to the first-direction is a short direction and a third-direction orthogonal to the first and second-directions is a longitudinal direction, and a holding member. The head unit has a first-head, a second-head adjacent to the first-head, and disposed in the second-direction, and a third head adjacent to the second-head, and disposed in the second-direction. The first head has a first-gripping portion provided on an upper surface. The second-head has a second-gripping portion provided on the upper surface. The third-head has a third-gripping portion provided on the upper surface. A position of the second-gripping portion with respect to the third-direction is different from positions of the first-gripping portion and the third-gripping portion with respect to the third-direction.

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 liquid discharge apparatus includes a nozzle plate with nozzles and actuators and a drive controller. First and second nozzles are directly adjacent to each other in a first direction. First and third nozzles are directly adjacent to each other in a second direction. The drive controller is configured to apply a drive signal to first, second, and third actuators corresponding to the first, second, and third nozzles, respectively, during a drive cycle. A difference between a first timing at which the drive signal is applied to the first actuator and a second timing at which the drive signal is applied to the second actuator and a difference between the first timing and a third timing at which the drive signal is applied to the third actuator is an odd number multiple of a half of an inherent vibration cycle of the liquid discharge apparatus.

A substrate includes a first substrate which has a first substrate through hole, and a second substrate which has a second substrate through hole and directly or indirectly overlaps the first substrate, the first substrate through hole and the second substrate through hole directly or indirectly communicate with each other to form a liquid supply path and a width D1 of an opening portion of the first substrate through hole on a surface of the first substrate closer to the second substrate, a width D2 of an opening portion of the second substrate through hole on a surface of the second substrate closer to the first substrate, a width D3 of an opening portion of the second substrate through hole on a surface of the second substrate farther from the first substrate have a relationship of D1<D2 and D3<D2.

A liquid discharging head includes a nozzle configured to discharge liquid, a pressure chamber communicated with the nozzle, and an individual channel communicated with the pressure chamber through a narrow part. The liquid discharging head also includes a common channel communicated with the individual channel, an energy generation element configured to generate energy, and a diaphragm configured to convey the energy to the pressure chamber. A metal oxide film is formed at inner walls of the nozzle, the pressure chamber, the narrow part, the diaphragm, and the individual channel, and a hydroxyl group has come out from the metal oxide film.

An example printhead includes a set of circulation channels for flowing a fluid therethrough, the set of nozzles including higher-pressure channels and lower-pressure channels; a first nozzle array having a first nozzle; a second nozzle array having a second nozzle, the first nozzle and the second nozzle forming a row region; a first inter-channel passage fluidically coupling the first nozzle to a first pair of adjacent circulation channels, the first pair including a higher-pressure channel on a first side of a lower-pressure channel; and a second inter-channel passage fluidically coupling the second nozzle to a second pair of adjacent circulation channels, the second pair including a higher-pressure channel on a second side of a lower-pressure channel, the second side being opposite the first side.

an adhesive having a first amount exists on a side of the first piezoelectric element line, of a joint of the wiring substrate and the pressure chamber substrate or the vibration plate, an adhesive having a second amount that is larger than the first amount exists on a side of the second piezoelectric element line of the wiring substrate, of the joint, and a first discharging element related to the first piezoelectric element line is different from a second discharging element related to the second piezoelectric element line.

There is provided a piezoelectric actuator, including: a vibration plate; a first piezoelectric body; a second piezoelectric body; a first electrode disposed on a first surface of the first piezoelectric body; a second electrode disposed on a second surface of the second piezoelectric body; an intermediate electrode disposed on an intermediate surface of the first piezoelectric body and overlapping with the first and second electrodes; an intermediate trace connected to the intermediate electrode on the intermediate surface and drawn out to one side in a first direction beyond the first piezoelectric body and the second piezoelectric body; a first trace overlapping with the intermediate trace in the thickness direction and being conducted with the intermediate trace; and a second trace overlapping with the intermediate trace in the thickness direction and being conducted with the intermediate trace.