A liquid discharge head includes an individual channel which includes: a nozzle; a pressure chamber; a descender of which one end in the first direction is nearer to the nozzle than the other end; and a second connecting channel connecting a second common channel and the one end of the descender. A central axis of the nozzle is positioned between the second common channel and a central axis of the descender in the second direction. The descender includes a first portion including the one end and a second portion positioned between the pressure chamber and the first portion in the first direction. In an end, of the descender, opposite to the second connecting channel in the second direction, an inner wall defining the one end of the first portion protrudes toward the second connecting channel in the second direction beyond an inner wall defining the second portion.

A liquid ejection head includes a plate with a plurality of nozzles arranged along a first direction through which liquid is ejected. A substrate is on the plate and includes a hole extending along the first direction by which the liquid is supplied. An actuator is on the substrate along the hole, The actuator has a plurality of pressure chambers, from which the liquid from the hole is ejected by the nozzles, and a plurality of air chambers. Each air chamber is between two of the pressure chambers that are adjacent to each other. A plurality of individual electrodes is formed on the substrate and each is connected to a corresponding one of the pressure chambers. A common electrode is formed on the substrate and an inner peripheral surface of the hole.

A droplet deposition apparatus comprising a droplet deposition head, a fluid supply and a controller, wherein: the droplet deposition head comprises one or more fluid chambers each having a nozzle, a fluid inlet path having a fluid inlet into the head, and ending in the one or more nozzles, and a fluid return path starting at the one or more nozzles and ending in a fluid return of the head; each fluid chamber comprises two opposing chamber walls comprising piezoelectric material and deformable upon application of an electric drive signal so as to eject a fluid droplet from the nozzle; the fluid supply is configured to supply a fluid to the fluid inlet at a differential pressure as measured between the fluid inlet and the fluid return; and the controller is configured to apply a drive signal to the piezoelectric chamber walls such that the nozzle or nozzles deposit droplets of a fluid having a viscosity in the range from 45 mPa.Math.s to 130 mPa.Math.s at a jetting temperature between 20° C. and 90° C., and wherein the differential pressure applied by the fluid supply causes a fluid return flow into the fluid return at a rate of between 50 ml/min and 200 ml/min. A method of operating the droplet deposition apparatus, and a control system for carrying out the method, are also provided.

There is provided liquid discharging head having unit heads. Each of the unit heads includes: first piezoelectric layer, driving electrodes arranged on surface of the first piezoelectric layer and to each of which one of first and second potentials is to be applied, and common electrode. The common electrode includes: potential receiving part configured to receive one of the first and second potentials; and extending part extending in extending direction orthogonal to the first direction, so as to overlap with the driving electrodes in the first direction. The unit heads are arranged so that the common electrodes of the plurality of unit heads are adjacent to each other in second direction orthogonal to the first direction. The extending directions of two of the common electrodes adjacent to each other in the second direction are opposite to each other.

According to one embodiment, an inkjet head includes a pressure chamber for ink, a nozzle plate including a nozzle connected to the pressure chamber, an actuator to change a volume of the pressure chamber, and a drive circuit that drives the actuator. The drive circuit drives the actuator according to a drive waveform including an expansion waveform, a first weak contraction waveform, a contraction waveform, and a second weak contraction waveform.

A liquid discharge head includes an individual liquid chamber having a nozzle through which a liquid is discharged in a liquid discharge direction, a piezoelectric element facing the individual liquid chamber, a first groove adjacent to the piezoelectric element in a nozzle array direction, a dummy individual liquid chamber without any nozzle, a dummy piezoelectric element facing the dummy individual liquid chamber, and a second groove adjacent to the dummy piezoelectric element in the nozzle array direction. The first groove extends in the liquid discharge direction. The second groove has a shorter length in the liquid discharge direction than the first groove.

According to one embodiment, a control circuit for an inkjet head or the like includes an input circuit configured to receive drive information for driving liquid ejection from a plurality of nozzle arrays. The drive information includes a drive signal value to be supplied to a channel of the plurality of nozzle arrays. A latch circuit array of the control circuit has latch circuits for storing the drive information for each array in the plurality of nozzle arrays. A setting register is configured to receive a setting value to configure the input circuit to correspond to a connection mode for the plurality of latch circuits. The setting value corresponds to the number of arrays in the plurality of nozzle arrays.

A first active region is made of a piezoelectric overlaps a midsection of a pressure chamber when viewed in plan through a pressure applying surface. A second active region is made of a piezoelectric member closer than the first active region to the pressure applying surface. The second active region extends over both a peripheral section of the pressure chamber and an outer region located outside the pressure chamber when viewed in plan through the pressure applying surface. A driver controls intensity of a first electric field applied to the first active region and intensity of a second electric field applied to the second active region such that the time period over which the first active region contracts and the time period over which the second active region contracts overlap or coincide with each other. The first electric field is more intense than the second electric field.

A head chip, a liquid jet head, a liquid jet recording device, and a method of manufacturing a head chip each capable of ensuring the tolerance of the displacement between nozzle holes and communication holes while ensuring the bonding area between an actuator plate and an intermediate plate are provided. The head chip according to an aspect of the present disclosure includes an actuator plate, a nozzle plate disposed so as to be opposed to the actuator plate, and an intermediate plate disposed between the actuator plate and the nozzle plate. The communication holes each include a groove part having a lower-side opening part opening toward the nozzle hole, and a penetrating part having an upper-side opening part opening toward an ejection channel. A dimension in the X direction in the upper-side opening part is larger than a dimension in the X direction in the upper-side opening part, and a dimension in the X direction in the upper-side opening part is no larger than a dimension in the X direction of the channel opening part opening on a channel opening surface of the ejection channel.

A head chip prevented from deteriorating in printing quality is provided. The head chip is provided with an intermediate plate which has a plurality of columns of communication hole groups for each channel column, the communication hole group having communication holes individually communicated with ejection channels of an actuator plate and arranged in a line in an X direction. The communication holes adjacent to each other in the X direction are arranged so as to be shifted in a Y direction from each other. The intermediate plate is provided with a non-penetrating groove closed by a nozzle plate, and a penetrating hole communicated with the non-penetrating groove, and communicated with an outside of the head chip through a non-ejection channel. A part of the non-penetrating groove is located in an inter-communication hole region. A minimum gap in the X direction between an opening edge of the communication hole and the non-penetrating groove in the inter-communication hole region is larger than a minimum gap in the X direction between the opening edge of the communication hole and the non-ejection channel.