A liquid droplet ejection device includes at least one first liquid droplet ejection unit including a first liquid holding unit and a first tip, the first tip to eject the first liquid in the first liquid holding unit as a first liquid droplet onto an object; at least one second liquid droplet ejection unit including a second liquid holding unit and a second tip, the second tip to eject the second liquid in the second liquid holding unit as a second liquid droplet onto the object; an object holding unit to hold the object; and a driving unit to move the first tip and the second tip in a first direction. An inner diameter of the second tip is larger than an inner diameter of the first tip. The first tip and the second tip are arranged along the first direction. The second tip is arranged behind the first tip.

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.

A fluid ejection device includes a fluid slot, at least one fluid ejection chamber communicated with the fluid slot, a drop ejecting element within the at least one fluid ejection chamber, a fluid circulation channel communicated with the fluid slot and the at least one fluid ejection chamber, and a fluid circulating element communicated with the fluid circulation channel. The fluid circulating element is to provide on-demand circulation of fluid from the fluid slot through the fluid circulation channel and the at least one fluid ejection chamber.

The fluid ejection device includes a plurality of nozzles and a plurality of ejection chambers that includes a respective ejection chamber fluidically coupled to a respective nozzle. A plurality of inlet passages are fluidically coupled to the ejection chambers and input fluid to the ejection chambers at a first pressure. A plurality of outlet passages are fluidically coupled to the ejection chambers and output fluid from the ejection chambers at a second pressure that is less than the first pressure. Fluid circulates through the ejection chambers based on the pressure difference between the first and second pressure. The fluid ejection device also includes at least one micropump fluidically coupled to at least one ejection chamber to pump fluid through the at least one ejection chamber.

A method for operating a printer can include draining a print material from a printer, placing a sacrificial metal into the printer, ejecting the sacrificial metal from a nozzle of the printer, and cooling to printer to a temperature that is below a melting point of the print material and the sacrificial metal. The print material can be or include aluminum and the sacrificial metal can be or include tin. The print material can be drained from the printer when the print material is in molten form, for example, from about 600° C. to about 2000° C. The sacrificial metal can be ejected from the nozzle at a temperature above the melting point of the sacrificial metal but below the melting point of the print material, for example, below about 300° C. The method can reduce or eliminate cracking of various printer structures such as the nozzle during a shutdown or cooling of the printer.

A jetting assembly that can be used to print a high-temperature print material such as a metal or metal alloy, an aqueous ink, or another material, includes an actuator for heating a gas such as a non-volatile gas within a gas cavity. The actuator rapidly heats the gas within the gas cavity, which rapidly increases a volume of the gas, thereby applying a pressure to the print material within an expansion channel that is in fluid communication with the gas cavity. In turn, the print material within the expansion channel applies a pressure to the print material within a nozzle bore, which forces a drop of the print material from a nozzle. The jetting assembly further includes a supply inlet that supplies the print material to the expansion chamber and the nozzle bore, for example, from a reservoir.

The fluid ejection device includes a plurality of nozzles and a plurality of ejection chambers that includes a respective ejection chamber fluidically coupled to a respective nozzle. A plurality of inlet passages are fluidically coupled to the ejection chambers and input fluid to the ejection chambers at a first pressure. A plurality of outlet passages are fluidically coupled to the ejection chambers and output fluid from the ejection chambers at a second pressure that is less than the first pressure. Fluid circulates through the ejection chambers based on the pressure difference between the first and second pressure. The fluid ejection device also includes at least one micropump fluidically coupled to at least one ejection chamber to pump fluid through the at least one ejection chamber.

The present disclosure relates to an induced electrohydrodynamic jet printing apparatus including an induced auxiliary electrode, and the induced electrohydrodynamic jet printing apparatus including an induced auxiliary electrode according to the present disclosure includes a nozzle for discharging supplied solution towards an opposite substrate through a nozzle hole formed at one end; a main electrode coated with an insulator and interpolated inside the nozzle, thus not contacting the solution inside the nozzle but separated from the solution; the induced auxiliary electrode made of a conductive material and formed at an outer surface of the nozzle; and a voltage supply for applying voltage to the main electrode.

A method for operating a printer can include draining a print material from a printer, placing a sacrificial metal into the printer, ejecting the sacrificial metal from a nozzle of the printer, and cooling to printer to a temperature that is below a melting point of the print material and the sacrificial metal. The print material can be or include aluminum and the sacrificial metal can be or include tin. The print material can be drained from the printer when the print material is in molten form, for example, from about 600° C. to about 2000° C. The sacrificial metal can be ejected from the nozzle at a temperature above the melting point of the sacrificial metal but below the melting point of the print material, for example, below about 300° C. The method can reduce or eliminate cracking of various printer structures such as the nozzle during a shutdown or cooling of the printer.

A narrow type inkjet print head chip is disclosed and includes a silicon substrate, an active component layer and a passive component layer. The active component layer is stacked on the silicon substrate and includes plural ESD protection units, plural encoder switches, plural discharge protection units and plural heater switches. The ESD protection units, the encoder switches, the discharge protection units and the heater switches are disposed in each of at least two high-precision regions of the active component layer. The corresponding positions and quantities of these components are the same in the at least two high-precision regions. The passive component layer is stacked on the active component layer and includes plural heaters, plural electrode pads, plural encoders and plural circuit traces. The circuit traces are electrically connected to the ESD protection units, the encoder switches, the heater switches, the heaters, the electrode pads and the encoders.