A liquid discharge head includes: a first pressure chamber group formed by pressure chambers arranged in a first direction; a second pressure chamber group formed by pressure chambers arranged in the first direction, and disposed side by side with the first pressure chamber group in a second direction; a first common channel extending in the first direction and communicating with the pressure chambers composing the first pressure chamber group; a second common channel extending in the first direction and communicating with the pressure chambers composing the second pressure chamber group; a first dummy pressure chamber disposed on one side in the first direction relative to the first pressure chamber group; and a second dummy pressure chamber disposed on the one side in the first direction relative to the second pressure chamber group.

There is provided a liquid discharge head, including: a channel unit; a vibration film; and piezoelectric elements. Pressure chambers form pressure chamber pairs arranged in a second direction. Each of the pressure chamber pairs includes a first pressure chamber and a second pressure chamber that communicate with an identical nozzle via a communication channel Rigidity of a first partition wall separating the first pressure chamber from the second pressure chamber, the first and second pressure chambers being included in each of the pressure chamber pairs, is different from rigidity of a second partition wall separating the first pressure chamber from the second pressure chamber, the first and second pressure chambers being adjacent to each other in the second direction and included in different pressure chamber pairs included in the pressure chamber pairs.

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.

A liquid ejection apparatus is configured to control a supply of a drive signal to a drive element by a controller so that a target period is either an ejection period or a non-ejection period based on print data. The drive signal includes an ejection pulse and a non-ejection pulse. The controller: does not supply the non-ejection pulse to the drive element when the target period is the non-ejection period and an elapsed time length from the last ejection period is less than the predetermined time length, and supplies the non-ejection pulse to the drive element when the target period is the non-ejection period and the elapsed time length is equal to or longer than the predetermined time length. The predetermined time length is an integral multiple or more of ½ of a natural vibration cycle of a meniscus of a liquid in the nozzle.

A liquid ejection module includes a pressure chamber, a supply flow channel that supplies a liquid to the pressure chamber, a collection flow channel that collects the liquid from the pressure chamber, a liquid feeding chamber connected to one of the supply flow channel and the collection flow channel, and a connection flow channel connecting the liquid feeding chamber to the other of the supply flow channel and the collection flow channel. The liquid feeding chamber includes a liquid feeding mechanism that circulates the liquid in the supply flow channel, the pressure chamber, the collection flow channel, the liquid feeding chamber, and the connection flow channel. A ratio of a sum of flow channel resistance of the supply flow channel, the pressure chamber, and the collection flow channel relative to flow channel resistance of the connection flow channel is equal to or above 0.5.

A liquid discharge head includes a liquid discharge substrate that has a discharge-orifice row, pressure generating elements, and pressure chambers. The liquid discharge head discharges a liquid in a block-by-block manner using sequential driving. The discharge-orifice row is disposed so as to incline at an angle θ=Arctan (d1/d2) relative to a direction extending orthogonal to the conveyance direction of the medium, in which d1 (μm) is a disposition spacing of the discharge orifices in the discharge-orifice row in the conveyance direction and d2 (μm) is a disposition spacing of the discharge orifices in the discharge-orifice row in the direction orthogonal to the conveyance direction. A partition wall is formed between adjacent pressure chambers so as to separate the adjacent pressure chambers from each other. The partition wall has a communicating portion that communicates the adjacent pressure chambers with each other.

There is provided a liquid discharge apparatus including: a head including a nozzle configured to discharge a liquid, and a driver element configured to apply a pressure to the liquid; a tank configured to store the liquid; a circulation channel configured to circulate the liquid between the head and the tank; a pump; and a controller. The controller is configured to carry out: a non-discharge flushing process of performing a non-discharge flushing by driving the driver element such that the liquid is not discharged from the nozzle; a switching process of switching the pump between ON and OFF; and a determining process of determining a frequency of driving the driver element in the non-discharge flushing process according to a circulation flow amount of the liquid changing due to the switching of the pump between ON and OFF in the switching process.

An inkjet print head includes a plurality of droplet jetting devices. The plurality of droplet jetting devices is formed of a nozzle layer defining, for each of the plurality of droplet jetting devices, a nozzle, a membrane layer carrying, on a membrane, a restrictor layer and an actuator for generating pressure waves in a liquid in a pressure chamber that is connected to the nozzle. The actuator is positioned in an actuator chamber in the restrictor layer, and a distribution layer defining a supply line for supplying the liquid to the pressure chamber. The restrictor layer includes an inlet restrictor having a cross-section and an outlet restrictor positioned on opposites sides of the actuator and having a cross-section that is different from the cross-section of the inlet restrictor.

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.