A head array includes heads arranged in a longitudinal direction at different positions shifted in a direction orthogonal to the longitudinal direction. Each head includes: pressure chambers communicating with nozzles; common supply channel tributaries communicating with the chambers; a common supply channel mainstream communicating with the common supply channel tributaries; common collection channel tributaries communicating with the chambers; a common collection channel mainstream communicating with the common collection channel tributaries; a supply port at one end of the common supply channel mainstream; and a collection port at one end of the common collection channel mainstream. The supply and collection ports are on a same side of each head in the longitudinal direction. A direction of flow of the liquid in each common supply channel tributary is opposite between the heads. A direction of flow of the liquid in each common collection channel tributary is opposite between the heads.

A liquid-discharging-head includes a nozzle having a first-nozzle-portion having a first-sectional-area and a second-nozzle-portion having a second-sectional-area larger than the first-sectional-area, a liquid chamber which communicates with the nozzle, and a piezoelectric-element which changes a pressure inside the liquid chamber, in which the piezoelectric-element is driven from the control section, and the liquid-discharging-head executes a first control in which an apex of a liquid surface is drawn into the second-nozzle-portion in a state in which an inner wall surface of the first-nozzle-portion is covered by a liquid film by decreasing the pressure inside the liquid chamber, and a second control in which a shape of the apex of the liquid surface is inverted to a protruding shape towed the opening and the droplet is discharged from the nozzle by increasing the pressure inside the liquid chamber in a state in which the inner wall surface is covered by the liquid film.

A liquid ejection head includes an ejection orifice forming member having a liquid ejection orifice and a substrate having a liquid flow path such that a liquid circulation flow path is formed between the ejection orifice forming member and the substrate. The liquid circulation flow path includes a bubble generation chamber facing the liquid ejection orifice and is branched from the liquid flow path so as to pass through the bubble generation chamber and join the liquid flow path. The substrate has an ejection energy generation element arranged to face the bubble generation chamber and a circulation energy generation element arranged at a different position to face the liquid circulation flow path. The gap between the ejection energy generation element and the ejection orifice forming member is different from the gap between the circulation energy generation element and the ejection orifice forming member.

A fluid recirculation channel for dispensing a plurality of fluid drop weights includes a number of sub-channels. The sub-channels include at least one pump channel, and a plurality of drop generator channels fluidically coupled to the at least one pump channel. The fluid recirculation channel further includes a number of pump generators incorporated into the at least one pump channel, a number of drop generators incorporated into drop generator channels, and a plurality of nozzles defined within the drop generator channels, the nozzles being at least as numerous as the number of drop generators.

The communication plate has a first layer that defines a wall surface of the communication flow channel, a second layer stacked on a side of the first layer opposite to the wall surface, and a third layer stacked on a side of the second layer opposite to the first layer, and the thermal expansion coefficient of the second layer is smaller than the thermal expansion coefficient of the first layer and is smaller than the thermal expansion coefficient of the third layer.

The electrohydrodynamic print head comprises a plurality of nozzles. Each nozzle has a central nozzle duct laterally surrounded by a nozzle wall. The top end of the nozzle duct communicates with an ink feed duct. An annular trench laterally surrounds the nozzle. An extraction electrode is located around the axis of the nozzle at a level below it, and a shaping electrode located laterally outside the nozzle duct. The shaping electrode is arranged within a ring having a horizontal width of less than the vertical distance between said shaping electrode and the extraction electrode or it is located above the trench. Both these measures allow to operate the device with high voltages with reduced risk of electrical breakdown.

Printheads and printers are described herein. In one example, a printhead includes a plurality of nozzles configured to eject ink drops of different sizes wherein a low drop weight (LDW) drop is ejected through a nozzle with a circular bore (CB), and a high drop weight (HDW) drop is ejected through a nozzle with a non-circular bore (NCB).

In a method of controlling a liquid ejecting apparatus, where the liquid ejecting apparatus includes a pressure chamber that communicates with a nozzle that ejects a liquid, a drive element that changes a pressure of the liquid in the pressure chamber, and a drive circuit that supplies the drive element with an ejection pulse that generates a change in the pressure that ejects the liquid from the nozzle, the method includes specifying a viscosity of the liquid in the nozzle and a surface tension of the liquid in the nozzle from a residual vibration when the pressure of the liquid in the pressure chamber is changed, and controlling a waveform of the ejection pulse according to the viscosity and the surface tension.

Aspects of the present disclosure are directed to forming a layer of material on a print head. As may be implemented in a manner consistent with examples herein, a layer of material from a transfer film is pressed against a surface of a print head, in which the surface defines fluid nozzle openings that extend from the surface into the print head. Portions of the material pressed onto the surface are therein adhered to the surface and caused to wrap over edges of the surface extending around the openings The transfer film is removed along with a thickness of the material pressed into contact with the surface that remains adhered to the transfer film, as well as some or all of other regions of the material over the openings The remaining layer of the material on the surface is thus formed with a uniform thickness.

A liquid discharge head includes a nozzle to discharge a liquid, a pressure generation chamber facing the nozzle, a common liquid chamber to supply the liquid to the pressure generation chamber, a fluid restrictor communicating with the pressure generation chamber, and a guide channel communicating with the fluid restrictor and the common liquid chamber. The guide channel includes a first adjacent portion communicating with the fluid restrictor. The pressure generation chamber has a first resonance period, and the guide channel has a second resonance period different from the first resonance period.