Actuator component for droplet ejection head and manufacturing method thereof

Abstract

An actuator component for a droplet ejection head and a manufacturing method thereof. The actuator component for a droplet ejection head includes an actuator assembly and a nozzle plate, the actuator assembly including a plurality of droplet ejection nozzles arranged in a droplet ejection array extending in an array direction, the plurality of droplet ejection nozzles arranged to be fluidly connected to a liquid supply source. The actuator component further includes a plurality of gas channels arranged in a gas channel array extending in the array direction, the plurality of gas channels arranged to be fluidly connected to a gas supply source. The actuator component for the droplet ejection head includes a plurality of droplet ejection nozzles arranged in a nozzle array extending in the array direction and a plurality of gas orifices arranged in an orifice array extending in the array direction, the gas orifices and the droplet ejection nozzles arranged in a repeating pattern extending in the array direction. The actuator component for each droplet ejection head is fluidly connected to one or more of the droplet ejection nozzles and is operable to eject droplets of liquid. The plurality of gas passages are arranged to be fluidly connected to one or more gas orifices for passing gas therethrough, and the actuator component is configured such that, in use, gas flowing through the gas orifices controls one or more properties of a liquid ejected from the droplet ejection nozzle. A method of manufacturing the actuator component. A droplet ejection device comprising one or more of the actuator components, further comprising a liquid supply source and a gas supply source, the gas supply source being configurable to be a positive or negative gas supply. A method of operating the droplet ejection device.

Description

[Technical Field]

[0001] The present disclosure relates to an actuator component for a droplet ejection head. The actuator component is particularly suitable for use in a droplet ejection head that is a drop-on-demand inkjet printhead. Or, more generally, for use in a droplet ejection device, specifically a droplet ejection device including one or more actuator components, or a droplet ejection device including one or more droplet ejection heads including one or more actuator components described herein. The actuator component provides an array of liquid chambers having actuators, which may be piezoelectric actuator elements, and nozzles. The piezoelectric elements may be, for example, lead zirconate titanate (PZT), although any suitable material may be used. The actuators are operable to expel droplets through nozzles in an ejection direction in response to an electrical signal. The actuator component further provides an array of gas channels, each having a gas orifice. The actuator component is operable to allow gas flow through the gas orifices to control droplet behavior or characteristics. The present invention also relates to methods of operating a droplet ejection device and methods of manufacturing an actuator component for a droplet ejection head. [Background technology]

[0002] Droplet ejection heads are now widely used in both traditional applications such as inkjet printing and 3D printing and other rapid prototyping technologies. Therefore, liquids, such as inks, may have novel chemical properties that allow them to adhere to new substrates and enhance the functionality of the deposited material. Droplet ejection heads have been developed for industrial applications, such as printing directly onto substrates like ceramic tiles or textiles, or forming elements like color filters in LCD or OLED displays for flat-screen televisions. These industrial printing techniques using droplet ejection heads enable short production runs, product customization, and even the printing of custom designs. It is therefore understandable that droplet ejection heads continue to evolve and become specialized to suit new and increasingly challenging applications. However, despite the significant developments in the droplet ejection head field, there remains room for improvement.

[0003] In recent years, there has been increasing interest in printing at greater distances from the substrate, i.e., increasing the so-called throw distance from the droplet ejection head to the substrate, as well as in controlling the properties of the environment surrounding the droplets to provide favorable conditions or mitigate unfavorable conditions. Summary of the Invention

[0004] In traditional markets such as ceramics and new applications such as direct-to-shape (DTS), the distance between the printhead and the substrate, or throw distance, is becoming increasingly longer. Longer throw distances can lead to larger droplet placement errors, which can be partially explained by the increased droplet flight time. Longer throw distances can also increase the woodgrain effect. This is the result of the complex flow that exists in the gap between the nozzle plate and the substrate due to the interaction between the airflow induced by the drop curtain (e.g., ejected droplets) and the airflow induced by the moving substrate. An obvious way to reduce flight time is to increase the (initial) droplet velocity. However, droplet velocity is limited by the available driving voltage (increasing this voltage can have undesirable side effects, such as increased heating) and the formation of satellite droplets above a certain critical velocity (typically 5 m / s). Furthermore, increasing droplet velocity can lead to stronger interactions between the airflow induced by the drop curtain and the airflow induced by the moving substrate. Solutions that have been used to date include increasing the spacing between nozzles in either the print direction or cross-print direction, which reduces print density and degrades image quality.

[0005] The present invention proposes a method to mitigate the effect of increasing throw distance and avoid the woodgrain effect by modifying the complex flow around the ejected droplets by sucking or blowing gas through a gas orifice adjacent to the nozzle.

[0006] Another area of ​​interest is controlling droplet properties. Such control can include controlling humidity, temperature, or the amount of oxygen present, or providing favorable conditions (or mitigating unfavorable conditions) so that droplet composition or performance is controlled. For example, the goal may be to reduce evaporation of solvent or carrier fluid from droplets in flight to control their behavior in flight or as they dry on a substrate. Or, the goal may be to reduce or prevent oxidation or solidification during flight by altering the oxygen balance in the atmosphere surrounding the droplets. Furthermore, the goal may be to protect droplets from dust particles in dusty environments.

[0007] The present invention proposes a method for injecting or sucking gas through gas orifices adjacent to the nozzle to modify the complex flow around the ejected droplets and / or provide a suitable device to further control the environment around the droplets and / or the composition of the droplets in flight and / or on the substrate, in addition to or instead of mitigating the woodgrain effect.

[0008] Aspects of the invention are set out in the accompanying independent claims, and details of particular embodiments of the invention are set out in the accompanying dependent claims.

[0009] According to a first aspect of the present invention, there is provided an actuator component for a droplet ejection head, comprising:

[0010] The device includes an actuator assembly and a nozzle plate, the actuator assembly including a plurality of fluid chambers arranged in an array of fluid chambers extending in an array direction.

[0011] the plurality of liquid chambers are arranged to be fluidly connectable to a liquid supply source; a plurality of gas passages arranged in an array of gas passages extending in an array direction; the plurality of gas flow paths are arranged to be fluidly connectable to a gas supply source; the array of liquid chambers and the array of gas flow channels are fluidly independent of each other; the nozzle plate having a plurality of droplet ejection nozzles arranged in an array of nozzles extending in an array direction; further comprising a plurality of gas orifices arranged in an array of orifices extending in an array direction; The gas orifices and the droplet ejection nozzles are arranged in a repeating pattern extending in an array direction. each liquid chamber fluidly connected to one or more of said droplet ejection nozzles and actuatable to eject droplets of liquid; the plurality of gas flow paths are fluidly connected to one or more respective gas orifices to allow gas to flow therethrough; The actuator component is configured such that, in use, gas passing through the gas orifice controls one or more properties of liquid ejected from the droplet ejection nozzle.

[0012] According to a second aspect of the present invention, there is provided a droplet ejection device comprising one or more actuator components according to the first aspect, and further comprising a liquid supply source and a gas supply source, the gas supply source being configurable to be a positive or negative pressure gas supply source.

[0013] According to a third aspect of the present invention, there is provided a method of operating a drop ejection device according to the second aspect. ejecting droplets from one or more droplet ejection nozzles in accordance with a printing instruction; A gas is flowed through the gas orifice to control the droplets of the liquid ejected from the droplet ejection nozzle.

[0014] There is provided a method of manufacturing an actuator component for a droplet ejection head according to a first aspect, the method comprising the steps of: forming an actuator assembly; forming an array of one or more liquid chambers in one or more strips of piezoelectric material extending in an array direction; Each of the fluid chambers is open along the height of the fluid chamber and defines an open flow path in the strip of piezoelectric material that is open at both ends along the length of the fluid chamber. forming an array of one or more gas channels in the one or more strips of piezoelectric material extending in the array direction; Each of the gas flow paths forms an open channel in the strip of piezoelectric material that is open in the height direction of the liquid flow path and is open at both ends in the extension direction of the liquid chamber.

[0015] the array of liquid chambers and the array of gas channels are fluidically independent of each other; -Fixedly attaching the nozzle plate to the actuator assembly. - forming a droplet ejection nozzle and a gas orifice in the nozzle plate before or after the step of fixedly attaching the nozzle plate to the actuator assembly, so that when assembled, the actuator component includes a droplet ejection nozzle fluidly connected to the liquid chamber and a gas orifice fluidly connected to the gas flow path. The gas orifices and the droplet ejection nozzles are arranged in a repeating pattern extending in an array direction. [Brief explanation of the drawings]

[0016] [Figure 1A] FIG. 1A shows a schematic diagram of an actuator component for a droplet ejection head according to an embodiment, with one side removed to show some of the fluid paths (liquid and gas) therein. [Figure 1B] FIG. 1B is a schematic diagram of a droplet ejection device including actuator components for a droplet ejection head according to the embodiment of FIG. 1A, with portions removed, the droplet ejection device further comprising liquid and supply gas paths and liquid and gas sources. [Figure 2A]FIG. 2A is a schematic diagram of a droplet ejection device including a portion of an actuator component for a droplet ejection head according to another embodiment, with one side removed to show details of its internal fluid paths (liquid and gas), liquid and supply gas paths, and liquid and gas supplies. [Figure 2B] FIG. 2B shows a portion of the schematic diagram of FIG. 2A, with portions of FIG. 2A designated AA and BB further removed to show further details of the fluid paths therein. [Figure 2C] FIG. 2C shows a portion of the schematic diagram of FIG. 2B, with a further portion cut away as indicated by CC in FIG. 2B, to show more detail about the fluid paths therein. [Figure 3] FIG. 3A shows the actuator component, showing a nozzle plate similar to that of FIGS. 1A and 1B, with the gas orifices offset in the y-direction relative to the nozzles. [Figure 3B] FIG. 3B shows an actuator part showing a nozzle plate similar to that of FIG. 3A, but with the gas orifice outlets being circular and smaller than the droplet ejection nozzles, and the gas flow passages narrower than the liquid chambers in the array direction. [Figure 3C] Figure 3C shows the actuator component, a nozzle plate, in which the gas orifice outlets are circular and larger than the droplet-ejecting nozzles, with multiple gas orifice outlets per gas channel, and the gas orifices are offset from the nozzles in the y-direction. [Figure 3D] Figure 3D shows the actuator component, showing the nozzle plate, where the nozzles are offset in the y direction, are larger than the gas orifice outlets, there are multiple gas orifice outlets per gas channel, and each nozzle is adjacent to multiple gas orifices, and the gas channels are narrower than the liquid chambers in the array direction. [Figure 3E]Figure 3E shows an actuator component, showing a nozzle plate, where the nozzles are arranged alternately in the y-direction and are larger than the gas orifice outlets, with multiple gas orifice outlets per gas channel, each nozzle adjacent to multiple gas orifices, and the gas orifices are arranged radially around the nozzle. [Figure 4] FIG. 4 shows an actuator component similar to the embodiment of FIGS. 2A-2C, but with two gas manifolds, multiple gas ports, and multiple fluid inlets and outlets. [Figure 5] FIG. 5 is a schematic diagram of a droplet ejection device including an actuator component and a movement device according to an embodiment. [Figure 6A] FIG. 6A illustrates a first step in the fabrication process of an actuator component according to an embodiment, which involves forming notches in one or more strips of piezoelectric material and securing the strips of piezoelectric material to a substrate to form a gas manifold. [Figure 6B] FIG. 6B illustrates a second step in a process for fabricating an actuator component according to an embodiment, which includes forming an array of one or more gas channels in one or more strips of piezoelectric material to create a plurality of open-ended gas channels in the one or more strips of piezoelectric material, the gas channels aligned in an array direction along the one or more strips of piezoelectric material. [Figure 6C] FIG. 6C illustrates a third step in the process of manufacturing an actuator component according to an embodiment, which includes forming one or more cover components that fit over at least a portion of the one or more strips of piezoelectric material and at least a portion of the substrate and fixedly attaching them to the one or more strips of piezoelectric material and at least a portion of the substrate. [Figure 6D] FIG. 6D illustrates a fourth step in the process of manufacturing an actuator component according to an embodiment, which involves connecting the liquid chamber through the cover portion and the strip of piezoelectric material to form an open channel in the strip of piezoelectric material and the cover portion. [Figure 6E]FIG. 6E illustrates a fifth step in the process of manufacturing an actuator component according to an embodiment, which includes attaching a nozzle plate to an actuator assembly to form the actuator component. [Figure 7] FIG. 7 is a schematic diagram of a portion of an actuator component according to another embodiment, similar to FIG. 2C, including two thermal control fluid manifolds. [Figure 8] FIG. 8 is a schematic diagram of a droplet ejection device including an actuator component and a movement device according to an embodiment such as that of FIG.

[0017] It should be noted that the drawings are not to scale and that certain features may be shown in exaggerated size for greater clarity. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE INVENTION Embodiments and various implementations thereof are now described with reference to the drawings, in which like reference numerals are used for like elements throughout the following description where appropriate.

[0019] 1A and 1B are schematic diagrams of an actuator component 100 for a droplet ejection head according to an embodiment. In FIG. 1A, one side of the actuator component 100 has been removed to reveal some of its internal fluid paths (liquid and gas). FIG. 1B further illustrates a droplet ejection device 1 including the actuator component 100 of FIG. 1A. The actuator component 100 in FIG. 1B is shown schematically with its top portion removed, as indicated by the dotted line XX in FIG. 1A, to provide greater visibility of the internal fluid paths.

[0020] The actuator component 100 includes a nozzle plate 70 and an actuator assembly 80. The nozzle plate 70 has a thickness T. As can be seen from FIG. 1A , the nozzle plate 70 has a plurality of droplet ejection nozzles 121 (hereinafter referred to as nozzles) capable of ejecting liquid arranged in a nozzle array 120, and a plurality of gas orifices 221 arranged in a gas orifice array 220. The nozzles 121 and the gas orifices 221 extend linearly in the array direction 10, and the nozzles 121 and the gas orifices 221 are alternately arranged at regular intervals in the array direction 10.

[0021] The actuator assembly 80 includes a plurality of liquid chambers 131 arranged in a liquid chamber array 130, with each liquid chamber 131 fluidly connected to one or more nozzles 121. The actuator assembly 80 further includes a plurality of gas channels 231 arranged in a gas channel array 230, with each gas channel 231 fluidly connected to one or more gas orifices 221. The actuator assembly 80 may include one or more components made of a piezoelectric material. For example, one or more of the walls of each liquid chamber 131 may include a piezoelectric material operable to eject liquid from each nozzle 121 in response to a printing command. It will be understood that this is in no way limiting, and other devices or methods may be used to eject liquid from each nozzle 121.

[0022] 1A is a so-called end shooter actuator, in which the nozzle plate 70 and nozzle 121 are disposed at one end of the liquid chamber 131 in the liquid chamber extension direction 5. It can be seen that the nozzle plate 70 is disposed so as to fluidly seal the liquid chamber 131 and the gas flow passage 231 in the liquid chamber extension direction 5. It can further be seen that in this arrangement, the droplet ejection direction 16 is aligned with the liquid chamber extension direction 5 and the negative y-direction. It will be appreciated that, in operation, the medium-facing surface 118 is generally appropriately aligned with the medium so that droplets ejected in the ejection direction 16 land at desired locations on the medium.

[0023] The nozzles 121 are separated by a nozzle spacing ns, and the gas orifices 221 are also separated by the nozzle spacing ns, so that the separation between a nozzle 121 and its adjacent gas orifice 221 is ns / 2, e.g., the center of substantially every gas orifice 221 is spaced apart from the center of an adjacent droplet-emitting nozzle 121 in the array direction 10. The nozzle spacing ns in the array direction 10 is conveniently measured from the center of a nozzle 121 or gas orifice 221 to the center of an adjacent nozzle or gas orifice, as appropriate. In some arrangements, the center of nearly every gas orifice 221 is spaced apart from the center of the nearest droplet-emitting nozzle 121 by the nozzle spacing ns / 2 in the array direction 10. In the actuator component 100, both the nozzles 121 and the gas orifices 221 have circular outlets; e.g., the gas orifices 221 in FIG. 1A have substantially the same shape as the nozzles 121. However, while it can be seen that the exit cross-sectional area of ​​the gas orifice 221 is smaller than the exit cross-sectional area of ​​the nozzle 121, it is understood that this is not limiting and that in other arrangements both exit cross-sectional areas may be the same, or the exit cross-sectional area of ​​the gas orifice 221 may be larger than the nozzle 121. For clarity, it is understood that the nozzle and orifice outlets are located at the medium-facing surface 118 of the nozzle plate 70.

[0024] In the embodiment of FIG. 1A , nozzle array 120 includes three nozzles 121_i-121-iii, and gas orifice array 220 includes three gas orifices 221_i-221_iii. This is by no means limiting, and in other arrangements, nozzle array 120 can include one or more nozzles, and gas orifice array 220 can include one or more gas orifices 221. Nozzle array 120 includes nozzles 121_i-121_n, where n is any integer, and gas orifice array 220 includes gas orifices 221_i-221_m, where m is any integer. The nozzles may be substantially identical to one another, or may be identical to one another within manufacturing capability limitations. Similarly, the gas orifices may be substantially identical to one another, or may be identical to one another within manufacturing capability limitations.

[0025] For simplicity, the actuator assembly 80 is shown as a monolithic component; however, those skilled in the art will appreciate that the actuator assembly 80 may be comprised of multiple components joined together in any suitable manner. Alternatively, it will be appreciated that additive manufacturing techniques, such as 3D printing, may be used to fabricate part or all of the actuator assembly 80, or part or all of the actuator component 100, as a single component. It can be seen that the actuator assembly 80 includes a liquid manifold 101 fluidly connected to the liquid chamber 131 (not shown in FIG. 1A ) and a gas manifold 201 fluidly connected to the array of gas flow paths 230 and, therefore, to each gas flow path 231 (as viewed from a cross-section of the first gas flow path 231_i). It can also be seen that the gas flow paths 231_i are fluidly connected to the gas orifices 221_i.

[0026] In this embodiment, the gas manifold 201 is positioned below the liquid chamber 131 in the Z direction, which is anti-parallel to the height direction 15 of the liquid chamber (and gas flow paths). The gas manifold 201 is also positioned at the base of the gas channels 231 in the height direction 15 of the liquid chamber, so that it intersects with and is fluidly connected to the gas flow paths 231.

[0027] It is generally understood that this spatial arrangement is not necessary, and other arrangements of the gas manifold 201 relative to the liquid chamber 131 are also contemplated. Furthermore, any suitable spatial arrangement of the gas manifold 201 relative to the liquid manifold 101 may be utilized. It is understood that such suitable spatial arrangements may be implemented so long as the gas manifold 201 is fluidly connected to the gas channel array 230, the liquid manifold 101 is fluidly connected to the liquid chamber array 130, and the gas paths 243 and the liquid paths 143 are fluidly isolated from one another.

[0028] The liquid chamber 131 and gas flow passage 231 are comprised of one or more layers deposited on some or all of their internal surfaces, such as a metal layer that enables actuation of the piezoelectric material and a protective coating layer that prevents fluids such as ink from damaging (e.g., corroding) the metal layer and passivates the electronics. Thus, the actuator component 100 is comprised of electrical traces and connections.

[0029] Referring to FIG. 1B, the nozzles 121, gas orifices 221, nozzle array 120, and gas orifice array 220 are as described above with respect to FIG. 1A. For simplicity, in FIG. 1B, the actuator component 100 is depicted as a single component, showing the position of the nozzle plate 70 and actuator assembly 80. However, it will be understood that the actuator component 100 in FIG. 1B is comprised of two separate components, as in FIG. 1A. The actuator component 100 comprises an array 130 of liquid chambers extending in an array direction 10. The array 130 of liquid chambers 131 comprises a plurality of liquid chambers 131. The liquid chambers (131_i-131_iii) extend side by side in the array direction 10. The array direction 10 is generally perpendicular to the liquid chamber height in a liquid chamber height direction 15. Each liquid chamber 131 is elongated in a liquid chamber extension direction 5, which is perpendicular to the liquid chamber height direction 15 in this embodiment. More generally, the liquid chambers 131 are elongated in a liquid chamber extension direction 5 non-parallel to the liquid chamber height H1, and each liquid chamber 131 opens to the liquid manifold 101 at a first end in the liquid chamber extension direction 5.

[0030] In this embodiment, the liquid chamber extension direction 5 is perpendicular to the array direction 10, but this is not required and in other arrangements the liquid chamber extension direction 5 may be at a different angle, for example to allow for longer liquid chambers within a given droplet ejection head footprint. Thus, more generally, the liquid chamber extension direction 5 may be at an angle other than 90° to the array direction 10.

[0031] The actuator component 100 further includes an array 230 of gas flow channels 231 extending in the array direction 10. The gas flow channels 231_i to 231_iii extend side by side in the array direction 10. Each gas flow channel 231 extends longitudinally in a liquid chamber extension direction 5 that is angled with respect to the array direction 10. The liquid chambers 131 and the gas flow channels 231 extend side by side in the array direction 10 so as to be parallel to each other, but this is not necessarily required, and other arrangements are also possible. In this embodiment, the array direction 10 is perpendicular to the liquid chamber extension direction 5, but this is not necessarily required, and in other embodiments, the liquid chambers 131 may be arranged at an angle other than 90° with respect to the array direction. For example, the liquid chambers 131 may be elongated in a direction non-parallel to the array direction 10. Similarly, the gas flow channels 231 may be elongated in a direction non-parallel to the array direction 10.

[0032] The liquid chamber 131 has a width Wl in the array direction 10 and a height Hl in the liquid chamber height direction 15 (negative Z direction). Similarly, the gas channel 231 has a width Wg in the array direction 10 and a height Hg in the liquid chamber height direction 15. Each gas channel 231 opens into the gas manifold 201 at its base in the liquid chamber height direction 15. The height Hg is greater than the height Hl (Hg > Hl) so that the gas channel 231 can fluidly connect the liquid chamber to the gas manifold 201 without impinging on the gas manifold 201. That is, to achieve fluidic independence, the gas channel 231 is deeper than the liquid chamber in the liquid chamber height direction 15. Furthermore, in this arrangement, because the gas manifold 201 intersects with the gas channel 231 (see, for example, cross section 231_i), the gas channel height Hg minus the gas manifold height Hm is greater than the liquid chamber height Hl (Hg - Hm > Hl). Furthermore, in this arrangement, in order to prevent the gas flow passage 231 from colliding with the liquid manifold 101, the gas flow passage 231 is shorter than the liquid chamber 131 in the liquid chamber extension direction 5 (Lg <Ll)。

[0033] The droplet ejection device 1 of FIG. 1B may include one or more actuator components described herein. More generally, the droplet ejection device 1 may include one or more droplet ejection heads that include one or more actuator components described herein. The droplet ejection device 1 may further include a liquid supply 140 and a gas supply 240. The liquid supply 140 may be fluidly connectable to the nozzle 121 via a liquid path 143, and the gas supply 240 may be fluidly connectable to the gas orifice 221 via a gas path 243. The liquid supply 140 may be fluidly connected to a liquid reservoir 146. The gas supply 240 may be configured to be a positive or negative gas supply; that is, it may supply gas to the gas orifice 221 (a positive gas supply) or draw gas through the gas orifice 221 into the actuator component 100 (a negative gas supply). The gas supply 240 may be fluidly connected to a gas reservoir 246.

[0034] It can be seen that the liquid pathway 143 comprises an inlet liquid pathway 141 (indicated by the shaded arrow 148) that fluidly connects the liquid source 140 to a liquid inlet 144 in the actuator component 100. In the actuator component 100, the liquid pathway 143 comprises a liquid manifold 101 fluidly connected to a plurality of liquid chambers 131 arranged in a liquid chamber array 130, with each liquid chamber 131 fluidly connected to a nozzle 121. As previously mentioned, the actuator component 100 of FIGS. 1A and 1B is a so-called end-shooter actuator component, in which the nozzles 121 are located at one end of the liquid chambers 131. In the embodiment of FIGS. 1A and 1B, the ejection direction 16 is the negative y-direction, which is further aligned with the longitudinal direction 5 of the liquid chambers and perpendicular to the array direction 10. Each liquid chamber 131 comprises at least one actuator, which may be a piezoelectric actuator element, and at least one nozzle 121. Each actuator of each liquid chamber 131 responds to an electrical signal in the ejection direction 16 to eject one or more droplets from the respective nozzle 121 (shown in FIG. 1B as droplet Dp121_iii ejected from nozzle 121_iii).

[0035] 1B, the gas path 243 can be seen to include a gas passage 241 fluidly connectable between the gas source 240 and the actuator component 100 (see white arrows 248). In the actuator component 100, the gas path 243 includes a gas manifold 201 fluidly connected to a plurality of gas passages 231, each of which is fluidly connected to a gas orifice 221. In other words, the gas passages 231 are fluidly connectable to the gas source 240 via the gas manifold 201. As previously mentioned, the gas source 240 can be configured to be a positive or negative gas source operable to induce a flow of gas through the gas orifices 221 in a positive or negative direction (out of or into the gas orifice 221, respectively). One or more gas ports 244 (not shown) may be present to connect the gas pathway 241 to the gas manifold 201 and to supply gas from the gas pathway 241 to the gas manifold 201 or to exhaust gas from the gas manifold 201 to the gas pathway 241 depending on whether the gas supply 240 is operating as a positive or negative gas supply.

[0036] The liquid path 143 and the gas path 243 are fluidly isolated from one another, ensuring that the two fluids do not mix at any stage between the liquid supply 140 and the outlet of the nozzle 121, or between the gas supply 240 and the outlet of the gas orifice 221. In other words, both the liquid path 143 and the gas path 243 are fluid-tight and isolated (or fluidically independent) from one another. As part of this, as explained in more detail above, the height Hl of the liquid chamber 131 and the height Hg of the gas channel 231 are different, as are their respective lengths Ll and Lg when the gas manifold 201 is positioned below the liquid chamber 131 in the negative liquid chamber height direction 15. In embodiments in which the actuators are shear-mode piezoelectric actuators, a further advantage of keeping the two paths fluidically independent is that, for droplet ejection heads in which the fluid is aqueous (i.e., water-based), some or all of the drive electrodes for driving the individual actuators can be located within the gas channel 221. In this way, the drive electrodes are physically isolated from contact with fluids such as ink, reducing or preventing electrical shorts.

[0037] In operation, the device 1 can include liquid flowing from the liquid source 140 via the liquid path 143 to the outlet of the nozzle 121. For example, liquid can flow from the liquid source 140 via the inlet liquid path 141 to a droplet ejection head including the actuator component 100. The liquid enters the actuator component 100 and enters the liquid manifold 101 via the liquid inlet 144. From the liquid manifold 101, the liquid enters each liquid chamber 131 at one end and flows along them in the liquid chamber extension direction 5. In other words, the actuator component 100 for a droplet ejection head includes one or more liquid manifolds 101, and the liquid chambers (131_i-o) are fluidly connectable to the liquid source 140 via said one or more liquid manifolds (101, 102).

[0038] Then, according to the printing instructions, the droplet ejection device 1 can eject droplets (in an ejection direction 16) from one or more nozzles 121. At the same time, the droplet ejection device 1 can flow gas through gas orifices 221 to control the droplets ejected from the nozzles 121. Such control may be to control the trajectory of the droplets, or to control the environment surrounding the droplets, their behavior or composition.

[0039] Depending on the type of gas supply 240 or the operating mode of the gas supply 240, the apparatus 1 may be arranged to cause gas to flow from the gas supply 240 via the gas path 243 through the gas orifice 221 in the jetting direction 16 (e.g., from the gas orifice 221) to control droplets, and such a gas supply 240 may be referred to as a "positive gas supply" 240. Alternatively, the apparatus 1 may be arranged such that the gas supply 240 causes gas to flow through the gas orifice 221 in the negative jetting direction 16 (e.g., from outside the actuator component 100 through the gas orifice 221 into the actuator component 100) and back to the gas supply 240 via the gas path 243 to control droplets. Such a gas supply 240 may also be referred to as a "negative gas supply" 240.

[0040] While not wishing to be bound by any particular theory, the inventors propose that to understand the effectiveness of positive gas flow in controlling droplet trajectories, Stokes drag must be considered. Stokes drag is the force acting on a small, spherical object, such as a droplet, when it is moving relative to the surrounding medium. As a result of Stokes drag, the velocity of the droplet decreases from an initial droplet velocity at the nozzle plate 70 to a minimum at the substrate. The proposed solutions described herein may aim to increase droplet velocity by reducing the velocity difference between the droplet and the surrounding medium.

[0041] In a typical uncontrolled situation, air near the droplets moves only in the direction of droplet ejection. This is because momentum is transferred from the droplets to the air, i.e., the droplets are decelerated. Ejecting gas from the gas orifice 221 adjacent to the nozzle 121 reduces the relative motion between the droplets and the surrounding medium because the surrounding medium is moving in the same direction and momentum transfer is no longer possible. In some configurations, the gas velocity exiting the gas orifice may be slower than the droplet ejection velocity (initial droplet velocity). In other configurations, droplet velocity may be increased by ejecting gas from the gas orifice 221 at a velocity exceeding the initial droplet velocity. In some configurations, the gas velocity can be controlled to reduce or prevent satellite formation from droplets or to delay satellite formation beyond a threshold velocity above which satellite formation normally occurs. In other configurations, the satellite formation threshold may be a critical gas velocity.

[0042] If the induced velocity of the surrounding medium is large compared to the relative motion between the droplet ejection head and the substrate (both the droplet ejection head and the substrate may be moving), the ejected gas can also have a significant positive impact on the complex flows that cause the woodgrain effect.

[0043] In yet other configurations, the gas may be drawn into the actuator component through gas orifice 221. It will be appreciated that whether the gas is blown through an orifice or drawn into the actuator component can be determined depending on the particular situation and operating conditions, as well as the droplet ejection head configuration, droplet ejection rate, printing duty cycle, substrate speed and / or droplet ejection head speed, etc. It will be appreciated that adding a tertiary flow, e.g., a gas flow (the primary flow is generated by the ejected droplets, and the secondary flow is induced by the moving substrate / printhead), can positively impact the complex flow between the droplet ejection head and the substrate.

[0044] In other configurations, gas source 240 may be used to supply a gas with specific properties, such as an inert gas, that reduces the exposure of the droplets to oxygen and therefore alters the reaction rate of oxygen-reactive compounds in the droplets (and thus, for example, alters their drying time on the substrate). Alternatively, using a gaseous form of a solvent, which is also a component of the jetted liquid, can alter the evaporation rate of the solvent from the droplets, for example, to favorably alter the drying rate of the droplets.

[0045] FIG. 2A is a schematic diagram of another embodiment of a droplet ejection device 2 including an actuator component 200 for a droplet ejection head. It can be seen that this actuator component 200 is a side-shooter actuator component, with the ejection direction 16 aligned with the height direction 15 of the liquid chamber, as compared to the end-shooter actuator component 100 of FIGS. 1A and 1B, which has the ejection direction 16 aligned with the extension direction 5 of the liquid chamber. Similar to device 1 of FIG. 1B, device 2 also includes liquid and gas paths 143, 243 and liquid and gas sources 140, 240. One side of actuator component 200 has been removed to show the fluid path details. As in FIG. 1B, actuator component 200 is shown as a single component, with the nozzle plate 70 and actuator assembly 80 positioned therein. However, it will be appreciated that actuator component 200 may be comprised of two separate components, as in FIG. 1A, or multiple separate components, as discussed above.

[0046] As can be seen from the cross-section of the gas flow path 231_i in FIGS. 2A-2C, the gas orifice 221_i is disposed midway along the gas flow path 231_i in the gas flow path extension direction 5 (which in this arrangement is the same direction as the liquid chamber extension direction 5). The other gas orifices 221_ii-iii and gas flow paths 231_ii-iii are disposed similarly. Similarly, in this embodiment, the nozzles 121_i-iii are disposed midway along the liquid chamber extension direction 5 along their respective liquid chambers 131_i-iii (see FIG. 2C), rather than at the ends of the liquid chambers as in the embodiment of FIGS. 1A and 1B. Therefore, the nozzle plate 70 is disposed on top of the actuator component 200, rather than at one end as in FIGS. 1A and 1B. Furthermore, it can be seen that the nozzle plate 70 is disposed to fluidly seal the liquid chambers 131 and the gas flow paths 231 in the liquid chamber height direction 15. Furthermore, the jetting direction 16 is the negative Z direction, coincident with the liquid chamber height direction 15 and perpendicular to the array direction 10. As previously mentioned, typically, during operation, the medium-facing surface 118 is properly aligned with the medium so that droplets ejected in the ejection direction 16 land at desired locations on the medium.

[0047] It can also be seen that the actuator component 200 comprises what is commonly known as a recirculation or through-flow design, whereby, in operation, the actuator component 200 is fluidly connected to the liquid path 143, and liquid flows from the liquid source 140, through the liquid path, to the actuator component 200, and then back to the liquid source 140 via the liquid path 143 (as indicated by the shaded arrows 148).

[0048] Portions of the liquid pathway 143 can be seen more clearly in FIGS. 2B and 2C, which include details of the actuator component 200 of FIG. 2A, with portions removed as indicated by dashed lines AA, BB, and CC. In operation, liquid travels from the liquid source 140 via the inlet liquid pathway 141 to the liquid inlet 144, from which it is supplied to the liquid manifold 101. It will be appreciated that the liquid pathway 143 may include additional fluid components within the droplet ejection head, fluid connections external to the droplet ejection head, and additional fluid components that transport the liquid from the actuator component, out of the droplet ejection head, and back to the liquid source 140. From the liquid manifold 101, liquid is supplied to one end of a plurality of liquid chambers 131 in the liquid chamber extension direction 5. The respective actuators of each liquid chamber 131 are operable to emit one or more droplets in the ejection direction 16 through respective nozzles 121 in response to an electrical signal. For example, a print command sends an electrical signal to an actuator in a selected fluid chamber 131_ii, which activates the actuator to eject fluid through the respective nozzle 121_ii and form a droplet (shown as droplet Dp121_ii in FIG. 2C).

[0049] It is understood that, depending on the printing instructions, none of the nozzles 121 may be ejecting fluid at any given time, or one or more of the nozzles 121 may be ejecting fluid to form the required image. The remaining un-ejected fluid passes through each fluid chamber 131 in the fluid chamber extension direction 5, exits each fluid chamber 131 at the opposite end from which it entered, and enters the fluid manifold 102. The fluid exits the fluid manifold 102 via one or more fluid outlets 145 (not shown). The liquid outlets 145 are also the points at which the liquid exits the actuator component 200 and returns to the liquid supply 140 via the return fluid path 142. Alternatively, the return fluid path 142 may include additional fluid components within the actuator component 200 and / or within the droplet ejection head, as well as fluid connections and additional fluid components external to the droplet ejection head that return the liquid to the liquid supply 140.

[0050] In some arrangements in which the actuator component 200 is used in a recirculating droplet ejection head, there are one or more liquid chamber 131 arrays and one or more liquid manifolds 101, 102, at least one of the one or more liquid manifolds being an inlet liquid manifold 101 and at least one of the one or more liquid manifolds being an outlet liquid manifold 102, and in operation, liquid flows from the liquid source 140 through the inlet liquid manifold 101, through the liquid chamber array 130, and back to the liquid source 140 via the outlet liquid manifold 102.

[0051] In other words, the liquid chambers 131 are open at opposite ends in the liquid chamber extension direction 5, and are fluidly connected at a first end to the liquid manifold 101 and at a second end to the liquid manifold 102. When operating in recirculation mode, liquid flows from the inlet liquid manifold 101 through the plurality of liquid chambers 131 via the first end of each liquid chamber 131, and into the outlet liquid manifold 102 via the second end of each liquid chamber 131. In accordance with printing instructions, droplets are ejected from one or more of the nozzles 121 in the array of nozzles 120, which are positioned midway through each liquid chamber 131 in the liquid chamber extension direction 5.

[0052] 2A, it includes gas path 241 connecting gas supply 240 to actuator component 200. If gas supply 240 is a positive gas supply, gas is supplied to gas orifice 221 and discharged in discharge direction 16 (indicated by white arrow 248), and gas path 241 is an inlet gas path 241. Alternatively, if gas supply 240 is a negative gas supply, gas is drawn from gas orifice 221 through gas path 243 into gas supply 240, in which case gas path 241 operates as a return gas path 241.

[0053] As shown in FIG. 2C , in some arrangements, the gas path 243 of the droplet ejection device 2 includes a gas path 241 and a gas path 242 fluidly connected to the gas manifold 201. If the gas supply 240 is a positive gas supply 240, the gas path 243 may be a recirculation path, in which case the gas path 241 is an inlet gas path 241 and the gas path 242 is a return gas path 242. In such an arrangement, gas is supplied to the gas manifold 201 via the inlet gas path 241, from which it is supplied to the multiple gas passages 231. A portion of the gas passes through the gas orifice 221, and the remainder returns to the gas supply 240 via the return gas path 242. This may be a desirable arrangement, for example, in dusty environments, where the gas flow rate may be higher than in a design without a return gas path, because only a portion of the gas flows through the gas orifice 221. The higher flow rate helps remove unwanted particles that may enter and accumulate in the gas path of the actuator component 200.

[0054] Rather than operating in a recirculation mode, both gas path 241 and gas path 242 can operate as inlet gas paths, supplying gas to manifold 201, which in turn supplies gas to multiple gas flow paths 231. In some modes of operation, the presence of a positive flow behind the gas orifices in gas flow path 231 can induce a negative pressure at the gas orifices. Alternatively, if gas supply 240 is a negative gas supply, both gas paths 241, 242 can operate as return gas paths 241, 242, drawing gas from either end of actuator component 200 and helping to provide a more uniform suction through gas orifices 221. Additionally, if gas supply 240 is a positive gas supply, both gas paths 241, 242 can operate as supply gas paths 241, 242, supplying gas to either end of actuator component 200.

[0055] 1A and 1B, the nozzles 121 and gas openings 221 of the actuator component 200 of FIGS. 2A-2C are alternately arranged along the array direction (10). They are also arranged in a regularly spaced alternating pattern, with the nozzles 121 spaced apart (nozzle spacing: ns) and the gas openings 221 spaced apart (nozzle spacing: ns), such that the distance between a nozzle 121 and its adjacent gas opening 221 is ns / 2 center-to-center in the array direction (10). The gas openings 221 and nozzles 121 of FIGS. 2A-2C are aligned with their centers in the liquid chamber extension direction 5. However, unlike the gas openings 221 of FIGS. 1A and 1B, which have substantially the same shape as the nozzles 121, the gas openings 221 of FIGS. 2A-2C have an elongated shape, in this example a rectangular slot, that extends beyond the nozzles 121 in both the positive and negative directions of the liquid chamber extension direction 5. This arrangement allows the gas flow through the gas openings 221 to form a "wall" or gas curtain between adjacent nozzles 121, reducing fluid interaction between droplets ejected from adjacent nozzles 121. This arrangement also reduces or prevents spreading of liquid on the nozzle plate 70, particularly the spread of leakage from one nozzle 121 to another, thereby reducing nozzle clogging and improving the reliability of the actuator component 200.

[0056] Various other features of the embodiments of FIGS. 2A-2C are as described above with respect to FIGS. 1A and 1B. For example, in order to prevent the gas flow path 231 from colliding with the liquid manifolds 101, 102, the gas flow path 231 is shorter than the liquid chamber 131 in the liquid chamber extending direction 5 (Lg < Ll). Similarly, the gas flow path 231 is deeper in the liquid chamber height direction 15, and its height Hg is higher than the height Hl of the liquid chamber 131, Hg - Hm > Hl, where the gas manifold 201 is disposed below the liquid chamber 131 in the z direction (or the negative liquid chamber (and gas flow path) height direction 15). The gas manifold 201 is also disposed at the base of the gas flow path 231 in the liquid chamber height direction 15, intersects the gas flow path 231, and is fluidly connected. However, other arrangements are possible as long as the gas manifold 201 is fluidly connected to the gas flow path 221 and is fluidly separated from the liquid chamber 131 or the liquid path 143 (i.e., not fluidly connected). Further, in this side shooter actuator arrangement, it can be seen that the gas manifold 201 faces the nozzle plate 70, i.e., it is disposed on the opposite side of the nozzle plate 70 from the gas flow path 231 and the liquid chamber 131 in the liquid chamber height direction 15.

[0057] 3A through 3E, which show views of actuator components 300 through 600 looking at the medium-facing surface 118 of the nozzle plate 70, with the locations of the liquid chambers 131 and gas channels 231 indicated by dashed lines. It can be seen in FIG. 3A that the gas orifices 221 and nozzles 121 are equally spaced in the array direction 10, but that gas orifices 221_1-221_7 are offset in the positive y-direction (direction of liquid chamber extension 5) from nozzles 121_1-121_6 by an offset distance Oo, such that the gas orifices 221 are spaced apart from the centers of the nozzles 121 in the liquid chamber extension direction 5. When the actuator component 300 is positioned in a droplet ejection device 1, 2, or 9, with the positive y-direction aligned with the direction of media movement 109, the gas orifice array 220 is downstream of the nozzle array 120. Alternatively, if the actuator component 300 is positioned in the droplet ejection device 1, 2, 9 with the negative y direction aligned with the direction of media movement 109, then the gas orifice array 220 is upstream of the nozzle array 120.

[0058] Furthermore, as described above with reference to the embodiment of Figures 2A to 2C, in the actuator component 300 of Figure 3A, the gas flow path 231 is shorter than the liquid chamber 131 in the liquid chamber extension direction 5, with Ll > Lg, which prevents the gas flow path from colliding with the liquid manifolds 101, 102 (not shown in Figure 3A) and enables fluid separation between the gas path 243 and the liquid path 143.

[0059] Referring to FIG. 3B here, it can be seen that the gas orifices 221 and the nozzles 121 are arranged at equal intervals in the array direction 10 and there is no offset in the y direction. However, from the dashed line, it can be seen that the gas flow path 231 is narrower than the liquid chamber 131 in the array direction 10 (Wg < Wl). As a result, for example, compared with FIG. 3A (where Wg = Wl), the nozzle interval ns is reduced, and the separation ns / 2 between the gas orifice 221 adjacent to the nozzle 121 is also reduced. Such an arrangement may be desirable because the nozzles 121 are closer to each other, improving the printing resolution. The gas orifices 221 in FIG. 3B are also smaller than the nozzles 121, but it is not limited to this. It can be understood that according to the relative gas flow rate and liquid flow rate required for a given application, the gas orifice 221 can be made larger or smaller than the nozzle 121 as long as the width of the narrow gas flow path 231 permits. More generally, the cross-sectional area of the gas orifice 221 can be made larger or smaller than that of the nozzle 121 according to the requirements of a specific application.

[0060] Also, different from the actuator component 300 in FIG. 3A, in the actuator component 400 in FIG. 3B, it can be seen that the gas flow path 231 is longer than the liquid chamber 13 in the liquid chamber extending direction 5, and Ll < Lg. As a result, it prevents the gas flow path from colliding with the liquid manifolds 101 and 102 (not shown in FIG. 3B), enabling fluid separation between the gas path 243 and the liquid path 143. In such an arrangement, the gas path 243 has two manifolds 201 and 202 that are fluid-connected one by one at both ends of the gas flow path 231 in the liquid chamber extending direction 5. During use, gas can flow from the gas manifold 201 along the plurality of gas flow paths 231 in the liquid chamber extending direction 5 and then flow into the gas manifold 202. In such an arrangement, furthermore, a single liquid manifold 101 can be provided under the liquid chamber 131 in the Z direction (for example, similar to the arrangement in FIGS. 2A to 2C, but the gas path 143 and the liquid path 243 are interchanged).

[0061] Alternatively, two liquid manifolds 101, 102 may be positioned below the liquid chambers 131 in the liquid chamber height direction 15 and fluidly connected such that, in use, liquid flows from the liquid manifold 101 along the plurality of liquid chambers 131 in the liquid chamber extension direction 5 and then into the liquid manifold 102. Alternatively, any other suitable arrangement of the liquid manifolds 101, 102 and gas manifolds 201, 202 may be used, so long as the two fluid paths 143, 243 remain fluidly separated and gas and liquid can be supplied to the respective plurality of gas flow paths 231 and plurality of liquid chambers 131. If the gas path 243 is arranged in a recirculating flow configuration, gas can be removed from the plurality of gas flow paths 231 by suitable fluid paths such as those described above with respect to Figures 2A-2C. Similarly, if the liquid path 143 is for a recirculating flow configuration, any suitable arrangement of fluid paths can be used to remove liquid from the plurality of liquid chambers 131.

[0062] 3C, which shows a similar arrangement to FIG. 3A, except that the actuator component 500 includes two rows of gas orifices 221 (labeled a and b) offset from the nozzle 121 by offsets Oo1 and Oo2 in the positive and negative y-directions, respectively, such that there are more than one gas orifice 221 per nozzle 121. This is not limiting, and it is understood that there may be multiple gas orifices 221 per droplet-ejecting nozzle 121, and that the multiple gas orifices 221 per droplet-ejecting nozzle 121 are spaced apart from the nozzle center in the liquid chamber extension direction 5. This means that each gas flow path 231 includes more than one gas orifice 221. The multiple gas orifices 221 per droplet-ejecting nozzle 121 are also spaced apart from the nozzle center in the array direction 10. Using this arrangement, the nozzle 121 may be surrounded by a larger volume of gas flow, allowing for improved control over the droplet trajectory and / or the composition of the gas surrounding the droplet, and therefore the droplet properties and / or behavior, e.g., evaporation rate. Additionally, although in FIG. 3C the cross-sectional area of ​​gas orifice 221 is larger than nozzle 121, this is by no means limiting and, as previously mentioned, gas orifices of other sizes may also be used.

[0063] Turning to FIG. 3D, this shows a similar arrangement to FIG. 3B, with the gas flow passages 231 narrower than the liquid chambers 131. The primary difference is that alternating nozzles 121 are offset in the y direction by a stagger distance sd, with odd-numbered nozzles 121_1, 121_3, etc. all at a single y-position y1, and even-numbered nozzles 121_2, 121_4, etc. all at a y-position y1+sd. Furthermore, it can be seen that each nozzle 121 is adjacent to four gas orifices, with each gas flow passage 231 comprising four gas orifices 221 (labeled a through d), except for gas passages 221_1 and 221_7 at the outermost edges of the gas flow passage array 230 in the array direction 10. These outermost gas passages 221_1 and 221_7 each comprise two gas orifices. 3D has at least two gas orifices 221 per droplet-ejecting nozzle 121 spaced apart from the nozzle center in the array direction 10, and at least two gas orifices 221 per droplet-ejecting nozzle 121 spaced apart from the nozzle center in the liquid chamber extension direction 5, and the droplet-ejecting nozzle 121 is substantially surrounded by the gas orifices 221. Such an arrangement having multiple gas orifices 221 per nozzle 121 can be beneficial when the flow rate and / or fluid properties of the liquid or medium velocity require more gas, or more gas orifices positioned around each nozzle (so that a larger portion of the circumference of each nozzle can be controlled) to control droplet velocity or other properties of the droplets, such as droplet humidity control.

[0064] In the actuator component 500 of FIG. 3C and the actuator component 600 of FIG. 3D, the gas flow passage 231 and the liquid chamber 131 are seen to have the same length in the liquid chamber extension direction 5. As with the previous embodiments, it will be appreciated that any suitable arrangement of the liquid manifolds 101, 102, 201, 202 can be used to supply liquid and gas to the respective gas flow passages 231 and liquid chambers 131 while maintaining fluid separation between the gas path 243 and the liquid path 143. For example, the liquid manifold and the gas manifold, as well as the liquid chamber 131 and the gas flow passage 231, may be positioned at different vertical heights in the Z direction so that the fluid paths 143, 243 do not impinge on one another. As is well known in the art, descenders can be used in the fluid paths 143, 243 to fluidly connect the gas orifices 221 and / or nozzles 121 to the respective gas flow passages 231 and liquid chambers 131. More generally, it will be appreciated that any suitable arrangement of the fluid paths 143, 243 is contemplated, so long as fluid separation of the two paths is maintained.

[0065] 3E shows an actuator part 700 similar to that of FIG. 3D, showing a nozzle plate 70 in which the nozzles 121 are arranged alternately in the extension direction 5 of the liquid chamber and are larger than the outlets of the gas orifices 221, there are multiple gas orifices 221 per gas flow passage 231, and each nozzle 121 is arranged adjacent to multiple gas orifices 221. Unlike FIG. 3D, in FIG. 3E the multiple gas orifices 221 are arranged at a radius R from the center C of the nozzle 121, and the gas orifices 221 substantially surround the nozzle 121.

[0066] 4, which is similar to actuator component 800 of FIGS. 2A-2C, with the primary difference being that two gas manifolds 201, 202 are positioned below (in the height direction 15 of the liquid chamber) and are fluidly connected to a plurality of gas flow paths 231, such that gas can be supplied from gas manifold 201 to gas flow paths 231 at one end in the liquid chamber extension direction 5, and gas can be discharged from gas flow paths 231 to gas manifold 202 at the opposite end in the liquid chamber extension direction 5. Gas manifolds 201, 202 can each be connected to one or more gas ports 244 and one or more gas ports 245. For example, there may be gas ports 244_a-244_j connected to gas manifold 201 and gas ports 245_a-245_k connected to gas manifold 202 (gas ports 244_a and 245_a are seen in FIG. 4). In this arrangement, a number of gas ports 244, 245 are positioned below the gas manifolds 201, 202 in the liquid chamber height direction 15. These can be conveniently connected to other gas paths within the droplet ejection devices 1, 2, 9.

[0067] In other arrangements, gas port 244 and gas port 245 can be located in different positions as long as fluid separation between gas path 243 and liquid path 143 is maintained. During operation, when gas supply 240 operates as a positive gas supply 240, such an arrangement can supply gas to and remove gas from multiple gas flow paths 231. For example, in this arrangement, gas port 244 operates as an inlet gas port 244 to supply gas to gas manifold 201, which then supplies gas to multiple gas flow paths 231. A portion of the gas can be exhausted from gas flow paths 231 through respective gas orifices 221, and the remainder can return to gas supply 240 via gas manifold 202 and gas port 245 operating as an outlet gas port 245 (see white arrows 248 in FIG. 4 ). Alternatively, when operating as a negative gas supply 240, gas may enter gas flow passage 231 through gas orifice 221, then flow through gas manifolds 201, 202 to gas supply 240, and then flow through both gas port 244 and gas port 245, which may act as an outlet for removing gas from gas manifolds 201, 202.

[0068] 4 shows a plurality of liquid inlets 144_a, 144_b fluidly connected to liquid manifold 101 and a plurality of liquid outlets 145_a, 145_b fluidly connected to liquid manifold 102. In this arrangement, the plurality of liquid inlets 144 and the plurality of liquid outlets 145 are positioned in the liquid chamber height direction 15 below liquid manifolds 101, 102. These may be conveniently connected to other liquid pathways within droplet ejection devices 1, 2, 9. It will be appreciated that in other arrangements, liquid inlet 144 and liquid outlet 145 may be positioned in other locations, so long as fluid separation between gas pathway 243 and liquid pathway 143 is maintained. In operation, such an arrangement may supply liquid from liquid source 140 via liquid pathway 143 to the plurality of liquid chambers 131, with liquid entering liquid chamber 131 from liquid manifold 101, which is supplied with liquid via liquid inlet 144. A portion of the liquid is ejected from the liquid chamber 131 through the nozzle 121 in response to a print command, and the remaining liquid can be returned to the liquid source 140 through the liquid manifold 202 and then to the liquid outlet 145.

[0069] Referring now to FIG. 5, a schematic diagram of a droplet ejection device 9 includes an actuator component 900 according to an embodiment, disposed within a droplet ejection head 902, having an actuator assembly 80 and a nozzle plate 70. The droplet ejection device 9 also includes a transport mechanism 105 for moving a deposition medium 103 and a controller 104. The droplet ejection head 902 is mounted above the deposition medium 103 such that a gap G exists between the deposition medium 103 and the nozzle plate 70. The deposition medium 103 moves in a media movement direction 109. The nozzle plate 70 has a media-facing surface 118 in which outlets of one or more nozzles 121 are disposed. The actuator component 900 is configured to eject droplets toward the deposition medium 103 through the one or more nozzles 121 in response to signals sent from the controller 104. The controller 104 can also control the transport mechanism 105.

[0070] Alternatively, there may be a master controller that controls all aspects of the droplet ejection device 9. Additionally, there may be a media encoder circuit 107. The droplet ejection device 9 further includes a liquid supply 140, a liquid path 143 including an inlet liquid path 141, a gas supply 240, and a gas path 243 including a gas path 241. Although not shown in FIG. 5 , the actuator component 900 further includes one or more gas orifices 221 for flowing gas through gas orifice outlets in the medium-facing surface 118. Similarly, the actuator component 900 may include one or more liquid chambers 131, one or more gas flow paths 231, etc., as described herein. The droplet ejection head 902 may include one or more actuator components 900. It will be generally understood that any of the actuator components 100-1000 described herein may be used in the droplet ejection device 9.

[0071] [How to operate] A method of operating any of the devices 1, 2, and 9 described herein may include ejecting droplets from a nozzle 121 in accordance with printed instructions and flowing gas through a gas orifice 221 to control droplets ejected from the droplet-ejecting nozzle 121. If the gas supply 240 is a positive gas supply 240, the method may further include arranging the gas supply 240 to supply gas from the positive gas supply 240 to the actuator component 100-900 via a gas passage 243, and flowing gas from an interior of the actuator component 100-900 to an exterior of the actuator component 100-900 through the gas orifice 221. If the gas supply 240 is a negative gas supply 240, the method may further include arranging the gas supply 240 to draw gas into the actuator component 100-900 through the gas orifice 221 and into the negative gas supply 240 via the gas passage 243. The method may further include controlling droplet composition through interaction with the gas flowing through the gas orifice 221. Additionally or alternatively, the method may include controlling the droplet ejection rate as a function of the gas velocity through the gas orifice 221. The method may include adjusting the gas velocity through the gas orifice 221 as a function of the droplet ejection rate. In some applications, the gas velocity through the gas orifice 221 may be greater than the droplet ejection rate.

[0072] The gas supply 240 may be continuous so that the flow of gas through the gas orifices 221 is substantially continuous, or alternatively may be pulsed. For example, a pulsing gas supply may be advantageous because it facilitates purging the gas path 243 or cleaning the nozzle plate 70. The gas supply 240 is adjustable to operate as a positive or negative gas supply depending on operational requirements.

[0073] If the apparatus 1, 2, 9 includes a return liquid path 142, the method may further include flowing uninjected liquid from the liquid chamber 131 to the liquid supply 140 via the return liquid path 142. The liquid may, for example, flow from the plurality of liquid chambers 131 to the return liquid manifold 102 and from there to the return liquid path 142. Similarly, if the apparatus 1, 2, 9 includes a return gas path 242, the method may further include flowing gas from the gas flow path 231 to the gas supply 240 via the return gas path 242. The liquid may, for example, flow from the plurality of gas flow paths 231 to the gas manifold 201 and from there to the return gas path 242.

[0074] Alternatively, if there is a second gas manifold 202, the gas flows from the plurality of gas flow paths 231 to the return gas manifold 202 and from there to the return gas path 242. It will generally be understood that depending on the application, the liquid used in the printing method can be one of many types of suitable liquid. For example, it can be a printing ink, such as an ink for printing on glass, plastic, ceramic, textile, paper, or cardboard.

[0075] Alternatively, the liquid may be suitable for newer uses, such as printing electrical components or for use in 3D printing applications to create 3D printed parts. Alternatively, the liquid may be suitable for printing into vehicles, buildings, or other 3D objects. It is further understood that the method may involve the use of a gas, which may include one or more of atmospheric air, air heated above ambient temperature or cooled below ambient temperature, humid air having a humidity higher than ambient, dehumidified air having a humidity lower than ambient, an inert gas, or a solvent used as a component of the liquid (wherein the solvent is in gaseous form).

[0076] [Manufacturing method] 6A-6D, the main steps of the method for manufacturing the actuator assembly 80 for the actuator components 100-900 of the droplet ejection heads described herein are summarized.

[0077] Step 1: Form one or more notches 81 in one or more strips of piezoelectric material 82 and then securely attach the strips of piezoelectric material 82 to a substrate 83 to form one or more gas manifolds 201, as shown in FIG. 6A. The strips of piezoelectric material 82 may be composed of, for example, lead zirconate titanate (PZT), although any suitable material may be used. This step also includes securely attaching a larger piece of piezoelectric material to the substrate 83 and then cutting, shaping, or machining the larger piece of piezoelectric material to form one or more strips of piezoelectric material 82. In this case, the larger piece of piezoelectric material has one or more pre-formed notches 81 to provide one or more gas manifolds 201.

[0078] Alternatively, the one or more gas manifolds 201 may be formed as one or more cutouts 81 (not shown) in the substrate 83 prior to attaching the one or more strips of piezoelectric material 82. In another embodiment of this method, the substrate 83 has one or more cutouts 81a and the one or more strips of piezoelectric material 82 has one or more cutouts 81b, and when the two parts are joined, the one or more gas manifolds 201 are formed by aligning the two cutouts 81a, 81b (see FIG. 6E). The cutouts 81 may be located at adjacent portions of the substrate 83 and the strips of piezoelectric material 82, or at the interface or boundary between them, in the height direction 15 of the liquid chamber.

[0079] Step 2: As shown in Figure 6B, an array of one or more gas channels 230 is formed in one or more strips 82 of piezoelectric material to create a plurality of open-ended gas channels 231 in one or more strips 82 of piezoelectric material, where the gas channels 231 are aligned in an array direction 10 along the one or more strips 82 of piezoelectric material.

[0080] Each gas flow channel 231 is formed in the strip 82 of piezoelectric material to include an open channel with openings at both ends in the liquid chamber extension direction 5, and also open along its extension to the opposite side of the substrate 83 (i.e., in the liquid chamber height direction 15). Furthermore, each gas flow channel 231 opens to and is fluidly connected to the gas manifold 201 on the side of the strip 82 of piezoelectric material facing the substrate 83. For example, the gas flow channels 231 may be formed deep enough to intersect with the cutouts 81 forming the gas manifold 201, i.e., may be partially or completely open on the side facing the substrate 83 so as to be fluidly connected to the gas manifold 201. Any suitable method can be used to form the gas flow channels 231, such as laser cutting, cutting with a dicing blade or saw, using a water jet cutter, or other suitable cutting tool. By way of example, a dicing blade having a width of 3 μm to 160 μm can be used. Depending on the required design, the gas flow passages 231 can be formed with any suitable width Wg, for example, a width of 3 μm to 160 μm, more preferably a width of 50 μm to 100 μm. The gas flow passages 231 may be narrower than the liquid chambers 131 in the array direction 10 (Wg <Wl)。

[0081] This step may also include forming the liquid chambers 131 such that each liquid chamber 131 has an open flow path in the strip of piezoelectric material 82 with openings at both ends in the liquid chamber extension direction 5, and the liquid chambers 131 are also open along their extension on the opposite side of the substrate 83 (i.e., in the liquid chamber height direction 15). Any suitable method can be used to form the liquid chambers 131, such as laser cutting, cutting with a dicing blade or saw, using a water jet cutter, or any other suitable cutting tool. Depending on the required design, the liquid chambers 131 can be formed with any suitable width Wl, for example, between 3 μm and 160 μm, more preferably between 50 μm and 100 μm. The liquid chambers 131 may be formed to have a height smaller than that of the gas flow paths 231 to avoid contact with the gas manifolds 201, 202. Preferably, the same method is used to form both the gas flow paths 231 and the liquid chambers 131. If the widths of both are the same (Wl = Wg), the same dicing blade can be used to form both the gas channels 231 and the liquid chamber 131. Alternatively, the liquid chamber 131 can be formed later (see step 4 below).

[0082] The open design of the strip of piezoelectric material 82 mounted on the substrate 83 allows, for example, a dicing blade to enter from the side and traverse the entire length of the liquid chamber 131 from one end to the other in the liquid chamber extension direction 5 to form the open flow path. That is, the liquid chamber can have a constant height Hl (and cross-sectional area) along the entire length in the liquid chamber extension direction 5. This allows for more uniform flow along the liquid chamber 131. This differs from other designs, for example, that require a dicing blade to be lowered from above to cut the liquid chamber 131, resulting in a lower flow path height at the end in the liquid chamber extension direction 5. In such a different design, varying depths result in varying liquid flow rates at the end of the liquid chamber 131. The gas flow path 231, like the liquid chamber 131, may be formed to have a constant height Hg (and cross-sectional area) along the entire length in the liquid chamber extension direction 5.

[0083] Step 3: Forming one or more cover portions 84_a, 84_b that conform to at least a portion of the one or more strips of piezoelectric material 82 and at least a portion of the substrate 83. The method may include fixedly attaching a first cover portion 84_a to each of the one or more strips of piezoelectric material 82 at a first end in the liquid chamber extension direction 5 and fixedly attaching a second cover portion 84_b to each of the one or more strips of piezoelectric material 82 at a second, opposite end in the liquid chamber extension direction 5. Step 3 may further include fixedly attaching the one or more cover portions 84_a, 84_b to at least a portion of the substrate 83, as shown in FIG. 6C. The cover portions 84_a, 84_b may be comprised of a single layer of material or may be formed from multiple fixedly attached layers of material. Alternatively, the cover portions 84_a, 84_b may be comprised of multiple pre-formed portions that conform to specific portions of the strips of piezoelectric material 82 or substrate 83, and then fixedly attached to each other.

[0084] The cover portions 84_a, 84_b can be formed by any suitable manufacturing technique, such as machining, molding, or cutting, grinding, laser ablation, etc. The material of the cover portions 84_a, 84_b can be the same material as the strip of piezoelectric material or a different material. The material of the cover portions 84_a, 84_b can include a material that is acoustically the same or similar as the strip of piezoelectric material 82 and / or the substrate 83. The cover portions 84_a, 84_b can be fixedly attached using any suitable method; for example, the attachment method can include bonding using any suitable bonding material. The bonding method can include depositing or 3D printing the bonding material in place. The bonding material can be curable, such as a thermosetting material, or if the cover portions 84_a, 84_b are formed from a UV-transparent material, a UV-curable material can be used. Epoxy resins (adhesive materials that can be cured in a temperature range that does not damage or impair the performance of the PZT) can be used. For example, it can be cured at temperatures below 140° C., and more preferably below 120° C. Depending on the design of the actuator component being manufactured, whether it is an end-shooter or side-shooter actuator, there may be cover components on one or both sides of the strip of piezoelectric material in the direction of liquid chamber expansion 5.

[0085] When there is one cover portion 84_a (as in the embodiment of FIGS. 1A-1B), the method can include fixedly attaching a first cover portion 84_a to each of the one or more strips of piezoelectric material 82 at a first end in the direction of liquid chamber expansion 5. When there are two cover portions 84_a, 84_b (as in the embodiment of FIGS. 2A-2C, 4, and shown in FIGS. 6C-6E), the method can further include fixedly attaching a second cover portion 84_b to each of the one or more strips of piezoelectric material 82 at a second, opposite end in the direction of liquid chamber expansion 5.

[0086] Step 4—Once the cover parts 84_a, 84_b are attached, openings 85_a, 85_b are formed in the cover parts 84_a, 84_b. Thus, the manufacturing method includes forming a plurality of openings 85_a, 85_b in the first and second cover parts 84_a, 84_b, where the first and second cover parts 84_a, 84_b include at least one opening 85_a, 85_b per liquid chamber 131 across a majority of the array of liquid chambers 130. The respective openings 85_a, 85_b per liquid chamber 131 are paired such that, for each liquid chamber 131, there is a continuous liquid path that passes through the first opening 85_a in the first cover part 84_a at the first end of the liquid chamber 131, through the liquid chamber 131, and through the opening 85_b in the second cover part 84_b at the second end of the liquid chamber 131. As mentioned above, with respect to the formation of the liquid chambers, the openings 85_a, 85_b may be formed using a cutting blade, entering from the side and traversing the entire length of each opening to form each opening 85_a, 85_b at a constant height Ha. This height may be the same as (Ha=Hl) or less than (Ha>Hl) the height of the adjacent liquid chamber 131, thereby providing a restriction at the entrance and / or exit to the liquid chamber in the direction of expansion 5 of the liquid chamber.

[0087] Forming the openings 85_a, 85_b may include passing a dicing blade through the cover portions 84_a, 84_b at appropriate locations in the array direction 10. If liquid chambers were not formed as part of step 2 (see above), this step may also include forming the liquid chambers 131, in which case this step is performed by passing a dicing blade through one or more cover portions 84_a, 84_b and the strip of piezoelectric material 82, one pass for each liquid chamber 131, to form a continuous liquid path therethrough. The liquid chambers 131 and openings 85_a, 85_b may be formed to be continuous through the cover portions 84_a, 84_b and the strip of piezoelectric material 82. The liquid chambers 131 and openings 85_a, 85_b may be formed to be shorter in height than the gas flow passages 231 to avoid impingement on the gas manifolds 201, 202. The liquid chamber 131 is open along its range on the opposite side of the substrate 83 in the height direction 15 of the liquid chamber, similar to the openings 85_a and 85_b.

[0088] To form the gas flow path 231 and / or the liquid chamber 131, the dicing blade can be lowered toward the substrate 83 on one side of the strip of the piezoelectric material 82, and then moved across the strip of the piezoelectric material 82 in the liquid chamber extending direction 5. When there are a plurality of strips of the piezoelectric material 82, the dicing blade can be moved to simultaneously form all the liquid chambers 131 and / or gas flow paths 231 at specific positions in the array direction 10. Next, the dicing blade can be lifted back to its original position, and the actuator assembly 80 can be gradually moved in the array direction 10 to form the liquid chambers 131 and / or gas flow paths 231 in the next row. When forming the liquid chamber 131, the dicing blade can be lowered lower than when forming the gas flow path 231, and as a result, the height Hl of the liquid chamber becomes lower than the height Hg of the gas flow path (Hl < Hg). Depending on the method and location of forming the gas manifold 201, the height Hl of the liquid chamber may also be lower than the value obtained by subtracting the height Hm of the gas manifold from the height Hg of the gas flow path (that is, Hl < (Hg - Hm)).

[0089] Alternative methods for forming the gas channels 231 and the liquid chambers 131 are contemplated. For example, both the liquid chambers and the gas channel arrays 130, 230 can be formed simultaneously by using a dicing blade to cut open channels (slots) in one or more strips of piezoelectric material 82, as described in step 2. For example, a dicing blade can be used to cut alternating deeper slots for the gas channels 231 and shallower slots for the liquid chambers 131 by appropriately changing the depth setting as the blade gradually moves in the array direction 10 along the strips of piezoelectric material 82. Next, one or more cover components 84_a, 84_b can be attached, and then the liquid chamber openings 85_a, 85_b through the cover components 84_a, 84_b can be formed in a second cutting operation. Alternatively, the liquid chamber openings 85_a, 85_b can be formed before attaching the cover components 84_a, 84_b to the strips of piezoelectric material 82. Alternatively, the liquid chamber openings 85_a, 85_b may be formed simultaneously with the liquid chambers 131 in a single operation, for example, by cutting both the one or more cover parts 84_a, 84_b and the one or more strips of piezoelectric material 82 using the same dicing blade.

[0090] In general, the manufacturing method includes selectively forming a plurality of openings 85_a in a first cover portion 84_a, said first cover portion 84_a including at least one opening 85_a for each liquid chamber 131 across a majority of the array of liquid chambers 130, and, if present, selectively forming a plurality of openings 85_b in said second cover portion 84_b, said second cover portion 84_b including at least one opening 85_b for each liquid chamber 131 across a majority of the array of liquid chambers 130. It will be appreciated that if an embodiment includes two cover portions 84_a, 84_b per strip of piezoelectric material 82, the openings 85_a, 85_b may be aligned with first and second ends of each liquid chamber 131, for example, so that liquid flows in from the first end and out from the second end.

[0091] Instead of cutting slots to form the openings 85_a, 85_b, other methods such as laser etching, drilling, or boring may be used to form the openings 85_a, 85_b. The openings 85_a, 85_b need not extend the entire height of the liquid chamber 131. The openings 85_a, 85_b may be one or more holes or orifices in one or more cover portions 84_a, 84_b that connect the liquid manifold 101 to a first end of the liquid chamber 131 and, if present, the liquid manifold 102 to a second end of the liquid chamber 131. If the gas flow passage 231 is longer than the liquid chamber 131, the above method steps may be modified appropriately to allow the gas flow passage openings to pass through the cover portions 84_a, 84_b.

[0092] Step 5—Once the actuator assembly 80 has been formed as needed and any additional steps and stages required (such as forming electrical traces and connections, adding protective layers for chemical / electrical isolation of components, adding additional components to complete the formation of the liquid manifolds 101, 102, etc.), the nozzle plate 70 can be attached to the actuator assembly 80 to form the actuator components 100-900. The gas orifices 221 and / or nozzles 121 can be formed before the attachment step and / or after the nozzle plate 70 is in place, as needed. The gas orifices 221 and / or nozzles 121 can be formed using any suitable method, such as laser ablation or etching.

[0093] It is generally understood that the electrical traces, drive electrodes, and connections can be deposited one at a time as successive layers on some or all of the exterior surfaces of the actuator components 100-900, e.g., on the substrate 83 and strips of piezoelectric material 82, using any suitable method, such as electroless plating or metal sputtering / evaporation. Cutting or other removal techniques can then be used to remove portions of the metal layer to form electrically isolated electrical traces, drive electrodes, and connections. If the electrical traces, drive electrodes, and connections are formed using electroless plating, the gas flow passages 231 can first be formed using shallow cuts that do not connect to the gas manifold 201. Next, the gas flow passages 231 and the liquid chamber 131 can be metallized, and then another cut can be used to connect the gas flow passages 231 to the gas manifolds 201, 202. These procedures prevent metallization of the gas manifolds 201, 202, which could cause an electrical short.

[0094] An alternative method is to use line-of-sight metal plating, which allows control over where and how deep the metal is deposited in the gas passages 231. Additionally, a dissolvable / removable block can be formed inside the gas manifolds 201, 202, and the gas passages can be cut as usual to connect the gas manifolds 201, 202 to the block. Metallization can then be performed, dissolving / removing the block along with the metal deposited on it, allowing connection between the gas passages 231 and the now-open gas manifolds 201, 202.

[0095] When the actuator component is for an end shooter, as shown in Figures 1A to 1B, the nozzle plate 70 is fixedly attached to the strip of piezoelectric material 82 at a second end in the liquid chamber extension direction 5 opposite the cover portion 84_a, thereby causing the nozzle plate 70 to fluidly seal the gas flow path 231 and the liquid chamber 131 in the liquid chamber extension direction 5.

[0096] 2A-2C , the nozzle plate 70 is fixedly attached to the strip of piezoelectric material 82 on one side of the liquid chamber height direction 15 (i.e., the side opposite the substrate 83), and functions to fluidly seal the liquid chamber 131 and the gas flow passage 231 in the liquid chamber height direction 15, as shown in FIG. 6E . Furthermore, in the arrangement of FIG. 6E , it can be seen that the nozzle plate 70 can also seal the openings 85_a, 85_b in the cover parts 84_a, 84_b that connect the liquid manifolds 101, 102 to the liquid chamber 131. The nozzle plate 70 can also seal the liquid manifolds 101, 102 in the liquid chamber height direction 15, although this is not required, and other arrangements can be used to form and / or seal the liquid manifolds 101, 102. It will be understood that the actuator components 100-900 may include further components, for example to seal the liquid manifolds 101, 102 on both sides in the extension direction 5 of the liquid chambers and on both ends in the array direction 10.

[0097] 1A-1C , the nozzle plate 70 can be attached to the strip of piezoelectric material 82 on one side of the liquid chamber extension direction 5 and fluidly seal the liquid chambers 131 and the gas flow passages 231 at a second end of the liquid chambers 131 in the liquid chamber extension direction 5, as shown in FIG. 1B . It can be appreciated that in such a design, the cover portion 84_a can be positioned on the opposite side of the nozzle plate 70 in the liquid chamber extension direction 5, i.e., at a first end of the liquid chambers 131. An opening 85_a can be formed in the cover portion 84_a to connect the multiple liquid chambers 131 and fluidly connect them to the liquid manifold 101. For example, a manufacturing method can include fixedly attaching a first cover portion 84_a to each of one or more strips of piezoelectric material 82 at a first end of the liquid chambers 131 in the liquid chamber extension direction. 5, and selectively forming a plurality of openings 85_a in the first cover portion 84_a so that the first cover portion 84_a includes at least one opening 85_a for each liquid chamber 131 across a majority of the array of liquid chambers 130.

[0098] Furthermore, it will be appreciated that if the actuator component does not have a return liquid path 142 or a second (return) liquid manifold 102 (i.e., it is not a recirculating actuator component of the liquid path 143), then only the first cover component 84_a with the opening 85_a at the first end of the liquid chamber 131 may be required, and the above procedure can be adjusted accordingly.

[0099] It will further be appreciated that the end shooter actuator component may require a top portion 86 (see FIG. 1A ) that can be attached to the substrate 83 and one or more gas manifolds 201, 202 opposite the strip of piezoelectric material to fluidly seal the gas passages 231 and liquid chamber 131 along the height 15 of the liquid chamber. The top portion 86 can be attached before or after the nozzle plate 70.

[0100] It will be appreciated that depending on the type of actuator component being fabricated, the order of the above steps may be varied as needed, and additional steps may be inserted as needed to form other features of the actuator component and droplet ejection head, such as forming electrical traces and connections, providing insulating and protective coatings, etc. It will be generally understood that the above fabrication method may be used, with appropriate adjustments, when there is one cover component 84_a for each strip of piezoelectric material 82 (i.e., for an end-shooter actuator component), or when there are two cover components 84_a, 84_b for each strip of piezoelectric material (i.e., for a side-shooter actuator component).

[0101] In general, the manufacturing method may involve forming one or more notches 81 in either a substrate 83 and / or a strip of piezoelectric material 82 . one or more strips of piezoelectric material 82 fixedly attached to a substrate 83, each of said one or more cutouts 81 being positioned adjacent to a respective interface between the substrate 83 and the strip of piezoelectric material 82 to form one or more gas manifolds 201, 202, and each of one or more arrays 130 of liquid chambers 131 being fluidly isolated from the one or more gas manifolds 201, 202. Here, each of the array 230 of one or more gas passages 231 is fluidly connected to at least one of the one or more gas manifolds 201, 202.

[0102] [General Considerations] The actuator components 100 to 900 for droplet ejection heads described here are generally understood to be composed of an actuator assembly 80 and a nozzle plate 70. It is understood that the actuator components may be composed of further components as required. The actuator assembly 80 includes a plurality of liquid chambers 131 arranged in a liquid chamber array 130 extending in the array direction 10, and the plurality of liquid chambers 131 are arranged so as to be fluidly connectable to a liquid supply source 140. The actuator assembly 80 further includes a plurality of gas flow paths 231 arranged in a gas flow path array 230 extending in the array direction 10, and the plurality of gas flow paths 231 are arranged so as to be fluidly connectable to a gas supply source 240. The liquid chamber array 130 and the gas flow path array 230 are arranged fluidly independent of each other.

[0103] The nozzle plate 70 may include a plurality of droplet ejection nozzles 121 arranged in a nozzle array 120 extending in the array direction 10, and a plurality of gas orifices 221 arranged in an orifice array 220 extending in the array direction 10. The gas orifices 221 and droplet ejection nozzles 121 may be arranged in a repeating pattern extending in the array direction 10.

[0104] Each liquid chamber 131 can be fluidly connected to one or more droplet-ejecting nozzles 121 and arranged to be actuated to eject droplets of liquid. The plurality of gas passages 231 can be arranged to be fluidly connected to one or more gas orifices 221, respectively, for flowing gas therethrough. In use, the actuator components 100-900 can be configured such that gas flowing through the gas orifices 221 controls one or more properties of the liquid ejected from the droplet-ejecting nozzles 121.

[0105] The actuator assembly 80 may include a substrate 83 and one or more strips of piezoelectric material 82 secured to the substrate 83. Each strip of piezoelectric material 82 has one or more notches 81 located at its interface with the substrate 83, and each notch 81 may be formed entirely in the substrate 83, entirely in the strip of piezoelectric material 82, or as aligned notches 81 a, 81 b in the substrate 83 and the strip of piezoelectric material 82, respectively. The notches 81 form gas manifolds 201, 202 that are fluidly connected to a plurality of gas passages 231 but fluidly isolated from a plurality of liquid chambers 131.

[0106] In some arrangements, the gas orifice array 220 begins before and ends after the nozzle array 120 in the array direction 10, with the gas orifices 221 located at the outermost positions in the positive and negative array directions 10. In such arrangements, the total number of gas orifices 221 is one more than the number of nozzles 121, e.g., m=n+1. It is further understood that the strip 82 of piezoelectric material can include buffer regions in the array direction 10. The buffer regions can include dummy liquid chambers and dummy gas channels that do not have nozzles or orifices, respectively. The dummy liquid chambers and dummy gas channels do not eject ink from the nozzles 121 or allow gas to flow from the orifices 221, but allow fluid (liquid or gas, respectively) to pass through them in use. Buffer regions including these can be found, for example, at the outer ends of the actuator components 100-900 in the array direction 10. The buffer regions therefore improve flow uniformity in the array direction 10 along the actuator components 100-900 and may also help improve stress profiles in the array direction 10 along the actuator components 100-900. Therefore, the buffer regions may improve droplet ejection performance and print quality (as actuator component stresses, as described herein, can lead to flow non-uniformities that "print" into the printed image or product and become visible defects). Buffer regions are also used to create gaps between nozzle clusters, for example, to control woodgrain effects. In some cases, the buffer regions may be comprised of areas without liquid chambers 131 or gas flow paths 231.

[0107] In some of the embodiments described herein, the nozzles 121 and gas orifices 221 in the medium-facing surface 118 have circular cross-sections, but it will be understood that this is by no means limiting and that in other arrangements, the nozzles 121 and / or gas orifices 221 may have other shapes. The gas orifices 221 may have any suitable shape, such as rectangular, circular, elliptical, or more complex geometric shapes. The gas orifices 221 described with reference to any of the embodiments and arrangements disclosed herein may have the same or a different cross-sectional shape as the nozzles 121. Furthermore, the gas orifices 221 may have a larger or smaller cross-sectional area than the nozzles 121. It will also be understood that the cross-sectional areas of the gas orifices 221 and nozzles 121 may be selected depending on operational requirements.

[0108] The cross-sectional shape and area of ​​the nozzle 121 and / or gas orifice 221 may be the same across the nozzle plate 70, e.g., the nozzle plate thickness T. The gas orifice 221 and / or the nozzle 121 may be angled to pass through the nozzle plate 70 at an angle relative to the nozzle plate thickness T. For example, the gas orifice 221 may be angled so that the gas flow through the gas orifice 221 is directed toward the nozzle 121. When there are multiple gas orifices 221 surrounding the nozzle 121, such angled gas orifices 221 may improve control of the droplet trajectory.

[0109] With respect to the gas orifices 221, the direction of gas flow is determined by the operation or type of gas supply 240, and therefore the terms "inlet" and "outlet" of the gas orifices 221 are generally understood to refer to gas orifice openings that are internal to the actuator component 100-900 and external to the actuator component 100-900, respectively (e.g., the "outlet" is at the medium-facing surface 118). The minimum diameter or width of the holes (gas orifices 221 or nozzles 121) in the nozzle plate 70 is determined in part by the material of the nozzle plate 70 and the available manufacturing methods. For example, while a minimum of 18 μm appears achievable with laser drilling, for silicon nozzle plates, deep reactive ion etching (DRIE) can be used to make the holes smaller (e.g., down to around 10 μm).

[0110] It will be appreciated that in an arrangement where the nozzles 121 in a given array 120 are staggered such that one or more adjacent nozzles 121 in the array direction 10 are offset from one another in the liquid chamber extension direction 5 (see, for example, Figures 3D, 3E, and 6E), the nozzle spacing n s can be measured by projecting the centerlines of the nozzles 121 onto a common line parallel to the array direction 10. This can also be done if the gas orifices 221 are similarly staggered in the liquid chamber extension direction 5 (see, for example, Figures 3C, 3D).

[0111] It is generally understood that a droplet ejection head can include one or more actuator components 100-900, as described herein. Furthermore, when an actuator component 100-900 is attached to a droplet ejection head, or when attached to a device 1, 2, 9 including multiple actuator components 100-900 and / or multiple droplet ejection heads (where the droplet ejection head includes one or more actuator components 100-900, as described herein), it is generally understood that the liquid pathway 143 and gas pathway 243 may differ from those described herein. The pathways may be more complex and may include additional external sections for connecting fluid sources 140, 240 to multiple actuator components 100-900 and / or multiple droplet ejection heads. Furthermore, fluid pathways within one or more droplet ejection heads may have additional components for connecting fluid sources (gas and liquid) to one or more actuator components 100-900 disposed within the droplet ejection head. There may also be additional components in the fluid paths to remove fluid (liquid and / or gas) from the actuator components 100-900. Furthermore, it is understood that the fluid path layouts 143, 243 may differ from those described herein and still perform the basic task of supplying fluid to the gas flow path 231 and the liquid chamber 131. Furthermore, it is generally understood that the liquid path 143 and the gas path 243 are fluidly isolated from each other throughout, regardless of what additional components they may include or whether they have a different layout.

[0112] It can be generally understood that the liquid can be a liquid suitable for ejection as droplets, i.e., a liquid for droplet ejection, such as a printing ink. It can be understood that printing inks vary widely in their composition, which can depend on the color to be printed, the pigments (if any) contained in the printing ink, the desired properties of the print medium (e.g., opacity, distribution, absorption, light reflection, etc.), and the type of medium to be printed on (e.g., paper, card, glass, cloth or textile, metal, ceramic, etc.). Furthermore, the liquid can be a functional fluid suitable for building textures, or printing electronic components such as circuit boards, or building three-dimensional objects (i.e., 3D printing).

[0113] In addition to, or instead of, controlling the droplet trajectory described above, the gas path 243 and gas orifice 221 may generally be used to control other characteristics of the ejected droplets or the environment surrounding the droplets. For example, gas may be used to control the humidity / drying rate of the droplets by using a gas that is more or less humid than the environment surrounding the droplet ejector 1, 2, or 9. Similarly, heated or cooled gas may be used to modify the environment near the droplets. Alternatively, gas may be used to create a controlled environment to promote or prevent reactions within the droplets, for example, by using an inert gas or a gas containing one or more components of a liquid. For example, if a particular solvent is used as part of a printing ink, the same solvent can be ejected in gaseous form through a gas orifice to modify, e.g., slow, the evaporation rate of the solvent from the droplets. Passing an inert gas through the gas orifice can reduce the oxygen concentration near the droplets, slowing or preventing oxygen-induced hardening of the droplets in flight. Additionally, the gas jets help keep environmental contaminants (such as dust) away from the nozzle plate 70, which is advantageous, for example, when printing in industrial environments where there are a lot of particulates in the air.

[0114] The droplet ejection head actuator components 100-900 described herein may include droplet ejection heads 131 with an actuator associated with each droplet ejection head 131 and operable to eject droplets through one or more droplet ejection nozzles 121 associated with each droplet ejection head 131. For example, one or more walls of the droplet ejection head 131 may be operable to eject droplets through the one or more droplet ejection nozzles 121. For example, one or more side walls of each droplet ejection head 131 may include a PZT and appropriate drive electrode arrangement, or the droplet ejection head 131 may include a roof-mode actuator arrangement. However, it will be appreciated that other forms of actuators may be used as long as they are suitable for ejecting fluid from the individual droplet ejection heads 131 through each nozzle 121 in response to a printing command.

[0115] It is generally understood that the liquid supply 140 and the gas supply 240 may consist of liquid and gas sources, such as internal liquid reservoirs and gas compressors, respectively, or may be connected to reservoirs 146, 246. Additionally, the liquid supply 140 and the gas supply 240 may consist of pumps, scrubbers, and other components necessary to supply the liquids and gases.

[0116] While the actuator components 100-1000 described herein include actuator assemblies 80 formed from a substrate 83 and a strip of piezoelectric material 82, this is by no means limiting. The actuator assemblies 80 may, for example, be comprised of one or more substrates 83 and multiple strips of piezoelectric material 82, each strip of piezoelectric material 82 including an array of one or more liquid chambers 130 and an array of one or more gas channels 230. Where appropriate, adjacent strips of piezoelectric material 82 may share a liquid manifold 101 or 102. For example, two strips of piezoelectric material 82 disposed on a substrate 83 may share a liquid manifold 101 disposed between them in the direction of extension of the liquid chambers. If the actuator component is a recirculation head, the strips of piezoelectric material 82 may further include respective liquid manifolds 102 on their outer edges in the direction of liquid chamber extension 5. Other arrangements of manifolds for two or more strips of piezoelectric material 82 are also contemplated. Furthermore, it will be understood that the embodiments described herein can be combined in any suitable manner, and more generally, when any of the actuator components 100-900 described herein are incorporated into a droplet ejection head, the head may include additional components not shown, such as fluid connections, printhead electronics, external electrical connections, etc.

[0117] It is further understood that in some arrangements, the gas flow paths 231 may not each be connected to one or more gas orifices 221, but instead provide a gas flow therethrough for thermal control purposes. Additionally, a thermal control fluid may flow through the gas flow paths 231, in which case it is generally referred to as a thermal control fluid flow path 231T. Here, the thermal control fluid may be a gas or a liquid. Accordingly, the arrangement may include the actuator components described herein and / or devices including the actuator components described herein. Methods of operating such actuator components and / or devices may include controlling the thermal properties of the thermal control fluid and, therefore, the thermal properties of the liquid droplets ejected from the nozzle 121. Such control may include, for example, cooling or heating the thermal control fluid before it enters the actuator components, depending on the operating conditions and the desired properties of the ejected liquid. Accordingly, the actuator components and / or the liquid path 143 and / or the thermal control fluid path 243T may include one or more temperature sensors linked to one or more controllers. Cooling can involve the transfer of thermal energy from the liquid in the liquid chamber 131 to the thermal control fluid in the thermal control fluid flow path 231T, but when the liquid is heated and ejected, the thermal energy transfer is from the thermal control fluid in the thermal control fluid flow path 231T to the liquid in the liquid chamber 131. Whether heating or cooling, it is generally understood that the thermal energy transfer occurs via conduction through the structure of the actuator component, particularly the shared wall 132 separating the liquid chamber 131 and the thermal control fluid flow path 231T. It is understood that controlling the temperature of the liquid can control other properties of the liquid, such as viscosity. It is understood that the method of constructing actuator components in this arrangement is similar to the method described above, with the exception of omitting the step of forming the gas orifices 221 in the nozzle plate 70.

[0118] Generally speaking, the actuator components of a droplet ejection head for thermal control consist of:

[0119] an actuator assembly and a nozzle plate; The actuator assembly includes a plurality of liquid chambers arranged in a liquid chamber array extending in an array direction; a plurality of thermal control fluid channels arranged in an array of thermal control fluid channels extending in an array direction; the plurality of liquid chambers and the plurality of thermal control fluid flow paths are fluidically independent; the plurality of liquid chambers are arranged to be fluidly connectable to a liquid supply; the plurality of thermal control fluid flow paths are arranged to be fluidly connectable to a thermal control fluid supply; the nozzle plate has a plurality of droplet-ejecting nozzles arranged in a nozzle array extending in an array direction; each liquid chamber fluidly connected to one or more droplet ejection nozzles and operable to eject droplets of the liquid; the plurality of thermal control fluid channels and the plurality of liquid chambers are arranged in a repeating pattern extending in an array direction; The actuator component is configured, in use, to control the thermal properties of liquid passing through the liquid chamber by passing a thermal control fluid through the thermal control fluid flow path, thereby controlling the thermal properties of liquid ejected from the droplet ejection nozzle.

[0120] The droplet ejection head may include one or more actuator components for thermal control. The droplet ejection device may include one or more actuator components for thermal control or one or more droplet ejection heads with one or more actuator components for thermal control. The droplet ejection device may further include a liquid supply, a liquid path, and a thermal control fluid path. The droplet ejection device may further include a thermal control fluid supply.

[0121] A method of operating such a droplet ejection device may include ejecting droplets of fluid from one or more droplet ejection nozzles in accordance with printing instructions. A thermal control fluid is flowed through the thermal control fluid passage to control, by heat transfer, the thermal properties of the liquid flowing through the liquid chamber, thereby controlling the thermal properties of the liquid ejected from the droplet ejection nozzle.

[0122] The method for manufacturing the thermal control actuator component includes the following steps. forming an actuator assembly; - forming one or more liquid chamber arrays within one or more strips of piezoelectric material extending in an array direction, each liquid chamber being open in the height direction of the liquid chamber and forming an open flow path within the strip of piezoelectric material that is open at a first end and a second end in the extension direction of the liquid chamber; - forming an array of one or more thermal control fluid flow paths within one or more strips of piezoelectric material extending in an array direction, each thermal control fluid flow path opening in the height direction of a liquid chamber and forming an open flow path within the strip of piezoelectric material opening at a first end and a second end in the extension direction of the liquid chamber, the liquid chamber array and the thermal control fluid flow path array being fluidically independent of each other. -Fixedly attaching the nozzle plate to the actuator assembly. Before or after the step of fixedly attaching the nozzle plate to the actuator assembly, droplet ejection nozzles are formed in the nozzle plate so that when assembled, the actuator components include droplet ejection nozzles fluidly connected to the liquid chambers.

[0123] A thermally controlled actuator component for a droplet ejection head may include an actuator assembly and a nozzle plate. The actuator assembly includes a plurality of liquid chambers arranged in a liquid chamber array extending in an array direction, the plurality of liquid chambers arranged to be fluidly connectable to a liquid supply source. the nozzle plate includes a plurality of droplet ejection nozzles arranged in a nozzle array extending in the array direction; Each liquid chamber is fluidly connected to one or more droplet ejection nozzles and operably arranged to eject droplets of liquid, and the actuator assembly further comprises two or more liquid manifolds arranged below the liquid chamber in the height direction of the liquid chamber. A first of the liquid manifolds is fluidly connected to one end of the plurality of liquid chambers in the extension direction of the liquid chambers, and a second of the two or more liquid manifolds is fluidly connected to a second opposite end of the plurality of liquid chambers in the extension direction of the liquid chambers, and are arranged so that, in use, liquid flows from the first liquid manifold along the plurality of liquid chambers from the first end to the second end and into the second manifold.

[0124] 7 is a schematic diagram of a cross section of an actuator component 900 similar to the cross section of FIG. 2C according to another embodiment. The embodiment is similar to the embodiment of FIGS. 2A-2C, but includes two thermal control fluid manifolds 201T, 202T. The thermal control fluid manifolds 201T, 202T are positioned in the z-direction below the liquid chamber 131, i.e., in the height direction 15 of the negative liquid chamber (and thermal control fluid flow path). The thermal control fluid manifolds 201T, 202T are also positioned at the base of the thermal control fluid flow path 231T in the height direction 15 of the liquid chamber, thereby intersecting and fluidly connecting with the thermal control fluid flow path. Thus, the actuator component 900 comprises two (or more) thermal control fluid manifolds (201T, 202T) arranged such that a first thermal control fluid manifold 201T is fluidly connected to a first end of a plurality of thermal control fluid flow paths 231T and second ends of two or more thermal control fluid manifolds 202T are fluidly connected to second opposite ends of the plurality of thermal control fluid flow paths 231T, and in use, thermal control fluid flows from the first thermal control fluid manifold 201T, along the plurality of thermal control fluid flow paths 231T, from first end to first end, and into the second thermal control fluid manifold 202T.

[0125] The thermal control fluid flow path 231T is fluidly connectable to the thermal control fluid supply 240T via the thermal control fluid manifold 201T (see, for example, FIG. 8). From FIG. 7, it can be seen that there are a plurality of thermal control fluid ports 244T_a-244T_c for connecting the thermal control fluid path 243T to the thermal control fluid manifold 201T of the actuator component 900. In operation, this allows thermal control fluid to be supplied from the thermal control fluid supply 240T to the thermal control fluid manifold 201T via the inlet thermal control fluid path 241T, as indicated by the open arrow 248T. The thermal control fluid flow path 231T is fluidly connectable to the return thermal control fluid path 242T via the thermal control fluid manifold 202T. The second thermal control fluid manifold 202T may include one or more thermal control fluid ports 245T (not shown in this view) for fluidly connecting the thermal control fluid manifold 202T to the return thermal control fluid path 242T.

[0126] 8, which is a schematic diagram of a droplet ejection device 7 having an actuator assembly 80 and a nozzle plate 70, and including an actuator component 1000 according to an embodiment disposed within a droplet ejection head 1002. The droplet ejection device 7 also includes a transport mechanism 105 for moving a deposition medium 103, and a controller 104. The droplet ejection head 1002 is mounted above the deposition medium 103 such that a gap G exists between the deposition medium 103 and the droplet ejection head 1002. The deposition medium 103 moves in a medium movement direction 109. The nozzle plate 70 has a medium-facing surface 118 in which outlets of one or more nozzles 121 are disposed.

[0127] The actuator component 1000 is arranged to eject droplets through one or more nozzles 121 toward the deposition medium 103 in response to signals sent from a controller 104. The controller 104 may also control the transport mechanism 105. Alternatively, there may be a master controller 112 that controls all aspects of the droplet ejector 7. Additionally, there may be a media encoder circuit 107. The droplet ejector 7 may further include a liquid supply 140, a liquid path 143 including an inlet liquid path 141 and a return liquid path 142, a thermal control fluid supply 240T, and a thermal control fluid path 243T including a thermal control fluid path 241T and a thermal control fluid path 242T. Similarly, the actuator component 1000 may include one or more liquid chambers 131 and one or more thermal control fluid flow paths 231T, etc., as described herein.

[0128] The droplet ejection device 7 may further include one or more temperature sensors (not shown). The temperature sensors may be provided in the thermal control fluid path 243 and / or the liquid path 143. The temperature sensors may be provided adjacent to the thermal control fluid source 240 and / or adjacent to the liquid source 140. The temperature sensors may be provided on the inlet thermal control fluid path 241 and the thermal control fluid return path 242. Additionally or alternatively, the temperature sensors may be provided on the liquid supply path 141. For example, the thermal control fluid path 243 may include temperature sensors at the inlet and / or outlet to the actuator component 100 and / or the inlet and / or outlet to the droplet ejection head. Similarly, the liquid path 143 may include temperature sensors on the liquid path 143 and / or at the inlet to the actuator component 100 and / or the inlet to the droplet ejection head. If the thermal control fluid pathway 243 includes a thermal control device 247 and / or a reservoir 246b, there may be one or more temperature sensors adjacent to the thermal control device 247 and / or the reservoir 246b.

[0129] The temperature measurements may be provided to a controller (not shown). The controller may control the droplet ejection device 1 to adjust the temperature of the liquid. For example, the controller may control the thermal control fluid supply 240 to vary the flow rate of the thermal control fluid. Additionally, the controller may control the thermal control device 247 to heat or cool the thermal control fluid. The controller may determine the required temperature and / or flow rate of the thermal control fluid to provide the desired liquid temperature, for example, using a look-up table or a calibration routine.

[0130] The droplet ejection head 1002 may include one or more actuator components 1000. It is generally understood that any of the throughflow-enabled actuator components described herein can be used in the droplet ejection device 7 and droplet ejection head 1002 to thermally control the fluid in the fluid chamber 131 and / or, if the actuator component also includes a gas orifice 231, to control the ejected droplets as described herein. It is generally understood that any of the actuator components 100-700 described herein can be modified to form a thermal control fluid path 243T, where the thermal control fluid is a gas or liquid. It is understood that the orifice 231 can be retained or omitted depending on the type of thermal control fluid and the desired operating conditions. The thermal control fluid path 243T may include one or more thermal control fluid devices 247T, such as heaters and / or coolers.

[0131] The thermal control actuator components described above can be described using the following numbered clauses:

[0132] 1. An actuator component 100-1000 for a droplet ejection head, an actuator assembly 80 and a nozzle plate 70; The actuator assembly 80 comprises a plurality of liquid chambers 131 arranged in a liquid chamber array 130 extending in an array direction 10. a plurality of thermal control fluid channels 231 arranged in a thermal control fluid channel array 230 extending in the array direction 10; The plurality of liquid chambers 131 and the plurality of thermal control fluid channels 231 are fluidly independent, The plurality of liquid chambers 131 are arranged to be fluidly connectable to a liquid supply source 140; the plurality of thermal control fluid flow paths are arranged to be fluidly connectable to a thermal control fluid source 240; The nozzle plate 70 includes a plurality of droplet ejection nozzles 121 arranged in a nozzle array 120 extending in an array direction 10. each liquid chamber 131 is fluidly connected to one or more droplet ejection nozzles 121 and operable to eject droplets of liquid; the plurality of thermal control fluid channels 231 and the plurality of liquid chambers 131 are arranged in a repeating pattern extending in an array direction 10; Here, the actuator component 100-1000 is configured such that, when in use, the thermal control fluid flowing through the thermal control fluid flow path 231 controls the thermal properties of the liquid flowing through the liquid chamber 131, thereby controlling the thermal properties of the liquid ejected from the droplet ejection nozzle 121.

[0133] 2. The actuator component 100-1000 according to clause 1, wherein the liquid chamber 131 is elongated in a direction non-parallel to the array direction 10.

[0134] 3. The actuator component 100-1000 according to clause 1 or clause 2, wherein the thermal control fluid flow path 231 is elongated and extends in a direction non-parallel to the array direction 10.

[0135] 4. The actuator component (100-1000) according to any preceding clause, wherein the thermal control fluid flow path (231) has a height greater than the liquid chamber (131) in the liquid chamber height direction (15) to achieve the fluid independence.

[0136] 5. An actuator component 100-1000 according to any preceding clause, further comprising one or more liquid manifolds 101, 102 and one or more thermal control fluid manifolds 201T, 202T, wherein the one or more liquid manifolds 101, 102 are fluidly independent from the one or more thermal control fluid manifolds 201T, 202T.

[0137] 6. The actuator component 100-1000 according to clause 5, wherein the one or more liquid manifolds 101, 102 are fluidly independent from the plurality of thermal control fluid flow paths 231T.

[0138] 7. The actuator component (100-1000) according to clause 5 or clause 6, wherein the one or more thermal control fluid manifolds (201T, 202T) are fluidly independent from the plurality of liquid chambers (131).

[0139] 8. An actuator component as described in any of clauses 5 to 7, wherein the thermal control fluid flow path 231T is fluidly connectable to the thermal control fluid source 240T via at least one of the one or more thermal control fluid manifolds 201T, 202T.

[0140] 9. An actuator component 100-1000 according to any one of clauses 5 to 8, comprising two or more thermal control fluid manifolds 201T, 202T, wherein a first of the thermal control fluid manifolds 201T is fluidly connected to a first end of a plurality of thermal control fluid flow paths 231T and a second of the two or more thermal control fluid manifolds 202T is fluidly connected to a second opposite end of the plurality of thermal control fluid flow paths 231T, and wherein the actuator component 100-1000 is arranged such that, in use, thermal control fluid flows from the first thermal control fluid control manifold 201T along the plurality of thermal control fluid flow paths 231T from the first end to the second end and into the second thermal control fluid manifold 202T.

[0141] 10. The actuator component 100-1000 of any preceding clause, wherein the liquid chamber 131 and the thermal control fluid flow path 231T are arranged parallel to each other.

[0142] 11. The actuator component 100-1000 according to any preceding clause, wherein the thermal control fluid flow paths 231T and the liquid chambers 131 are arranged in an alternating relationship extending in the array direction 10.

[0143] 12. The actuator component 100-1000 of any preceding clause, wherein the thermal control fluid flow path 231T is provided with drive electrodes and / or electrical traces.

[0144] 13. The actuator component 100-1000 according to any preceding clause, wherein the thermal control fluid flow path 231T is narrower than the liquid chamber 131 in the array direction 10.

[0145] 14. A droplet ejection head comprising one or more of the actuator components 10 to 1000 described in any one of clauses 1 to 13.

[0146] 15. A droplet ejection device 1, 2, 7, 9 comprising one or more actuator components 100-1000 according to any of clauses 1 to 13, or one or more droplet ejection heads according to clause 14, and further comprising a liquid supply section 140, a liquid path 143, and a thermal control fluid path 243T.

[0147] 16. The droplet ejection device 1, 2, 7, 9 according to clause 15, further comprising a thermal control fluid supply 240T.

[0148] 17. The droplet ejection device 1, 2, 7, 9 according to clause 15 or clause 16, wherein the thermal control fluid path 243T includes a return thermal control fluid path 242T.

[0149] 18. The droplet ejection device 1, 2, 7, 9 according to any one of clauses 15 to 17, wherein the liquid path 143 includes a return liquid path 142.

[0150] 19. The droplet ejection device 1, 2, 7, 9 according to any one of clauses 15 to 18, further comprising a thermal control fluid reservoir 246bT.

[0151] 20. A droplet ejection device 1, 2, 7, 9 as described in any one of clauses 15 to 19, wherein the fluid path 143, 243T is arranged so that, in use, the thermal control fluid flows along the thermal control fluid flow path 231T in a direction opposite to the flow direction of the liquid in the liquid chamber 131.

[0152] 21. The droplet ejection device 1, 2, 7, 9 according to any one of clauses 15 to 20, further comprising one or more thermal control devices 247T.

[0153] 22. A method of operating a droplet ejection device 1, 2, 7, 9 according to any one of clauses 15 to 21, comprising: ejecting droplets from one or more of the droplet ejection nozzles 121 in accordance with a printing instruction; By flowing a thermal control fluid through the thermal control fluid flow path 231T, the thermal properties of the liquid flowing through the liquid chamber 131 are controlled by heat transfer, thereby controlling the thermal properties of the liquid ejected from the droplet ejection nozzle 121.

[0154] 23. The method of clause 22, wherein the liquid is a droplet ejection liquid.

[0155] 24. The method of clause 22 or clause 23, wherein the thermal control fluid is a liquid.

[0156] 25. The method of clause 22 or clause 23, wherein the liquid and the thermal control fluid are supplied from a common liquid source 140.

[0157] 26. The method of any one of clauses 22 to 25, wherein the flow rates of the liquid and the thermal control fluid through the droplet ejection devices 1, 2, 7, 9 are independently controlled.

[0158] 27. The method of any one of clauses 22 to 26, wherein the temperatures of the liquid and the thermal control fluid flowing through the droplet ejection devices 1, 2, 7, 9 are independently controlled.

[0159] 28. The method of any one of clauses 22 to 27, wherein the thermal control fluid comprises one or more of atmospheric air, air heated above ambient temperature or cooled below ambient temperature, humid air having a humidity higher than ambient, dehumidified air having a humidity lower than ambient, an inert gas, or a noble gas.

[0160] 29. The method of any one of clauses 22 to 27, wherein the thermal control fluid comprises a refrigerant fluid.

[0161] 30. The method of any one of clauses 22 to 27, wherein the thermal control fluid comprises water.

[0162] 31. When dependent on clause 23, the method of any one of clauses 23 to 27, wherein the thermal control fluid includes the droplet ejection liquid.

[0163] 32. A method of manufacturing an actuator component 100-1000 for a droplet ejection head, the method comprising the steps of: forming the actuator assembly 80; forming one or more arrays 130 of liquid chambers 131 in one or more strips of piezoelectric material 82 extending in the array direction 10; Each of said liquid chambers 131 is open in the height direction 15 of the liquid chamber and forms an open flow path in the strip of piezoelectric material 82 that is open at first and second ends in the extension direction 5 of the liquid chamber. forming one or more arrays of thermal control fluid channels 231T in the one or more strips 82 of piezoelectric material extending in the array direction 10; Each of the thermal control fluid channels 231T forms an open channel in the strip of piezoelectric material 82 that opens in the height direction 15 of the liquid chamber and at first and second ends in the extension direction 5 of the liquid chamber. The liquid chamber array 130 and the thermal control fluid flow path array 230T are fluidly independent of each other; The nozzle plate 70 is fixedly attached to the actuator assembly 80. - Before or after the step of fixedly attaching the nozzle plate 70 to the actuator assembly 80, a droplet ejection nozzle 121 is formed in the nozzle plate 70 so that when assembled, the actuator component includes a droplet ejection nozzle 121 fluidly connected to a liquid chamber 131.

[0164] 33. The method according to clause 32, further comprising: - forming one or more notches 81 in either the substrate 83 and / or the strip of piezoelectric material 82; - fixing and attaching the one or more strips of piezoelectric material 82 to the substrate 83, such that each of the one or more cutouts 81 is positioned adjacent a respective interface between the substrate 83 and the strip of piezoelectric material 82 to form one or more thermal control fluid manifolds 201T, 202T. wherein each of the array 130 of one or more liquid chambers 131 is fluidly isolated from the one or more thermal control fluid manifolds 201T, 202T; and Here, each of the arrays 230T of one or more thermal control fluid channels 231T is fluidly connected to at least one of the one or more thermal control fluid manifolds 201T, 202T.

[0165] 34. The method according to clause 32 or clause 33, further comprising the step of: At a first end in the liquid chamber extension direction 5, a first cover portion 84_a is fixedly attached to each of the one or more strips of piezoelectric material 82.

[0166] 35. The method according to clause 34, further comprising the steps of: - selectively forming a plurality of openings 85 in the first cover portion 84, the first cover portion 84 comprising at least one opening 85 per liquid chamber 131 across a majority of the array of liquid chambers 131;

[0167] 36. The method described in clause 35, wherein the step of fixedly attaching the nozzle plate 70 includes attaching the thermal control fluid flow path 231T and the liquid chamber 131 to a band of piezoelectric material 82 at a second end of the nozzle plate 70 in the liquid chamber extension direction 5, and the nozzle plate 70 functions to fluidly seal the thermal control fluid flow path 231T and the liquid chamber 131 in the liquid chamber extension direction 5.

[0168] 37. The method according to clause 34, further comprising the steps of: At a second opposite end in the direction of extension 5 of the liquid chamber, a second cover portion 84_b is fixedly attached to each of the one or more strips of piezoelectric material 82.

[0169] 38. The method according to clause 37, further comprising the steps of: - Selectively forming a plurality of openings 85 in the first and second cover portions 84, the first and second cover portions 84 having at least one opening per liquid chamber 131 across a majority of the array of liquid chambers 130.

[0170] 39. The method described in clause 38, wherein the step of fixedly attaching the nozzle plate 70 includes attaching the thermal control fluid flow path 231T and the liquid chamber 131 to a strip 82 of piezoelectric material on one side of the liquid chamber height direction 15, and the nozzle plate 70 functions to fluidly seal the thermal control fluid flow path 231T and the liquid chamber 131 in the liquid chamber height direction 15.

[0171] 40. An actuator component 100-1000 for a droplet ejection head, an actuator assembly 80 and a nozzle plate 70; The actuator assembly 80 includes a plurality of liquid chambers 131 arranged in a liquid chamber array extending in an array direction. The plurality of liquid chambers 131 are arranged so as to be fluidly connectable to a liquid supply source. The nozzle plate 70 includes a plurality of droplet ejection nozzles 121 arranged in a nozzle array 120 extending in the array direction 10 . Each liquid chamber 131 is fluidly connected to one or more droplet ejection nozzles 121 and is operable to eject droplets of liquid. The actuator assembly 80 further includes two or more liquid manifolds 101 , 102 disposed below the liquid chamber 131 in the liquid chamber height direction 15 . A first one of the liquid manifolds 101 is fluidly connected to one end of a plurality of liquid chambers 131 in the liquid chamber extension direction 5 . A second liquid manifold 102 of the two or more liquid manifolds 102 is fluidly connected to second opposite ends of the plurality of liquid chambers 131 in the liquid chamber extension direction 5 . In use, liquid is arranged to flow from the first liquid manifold 101 to the second manifold 102 along a plurality of liquid chambers 131 from the first end to the second end.

[0172] 41. An actuator component 100-1000 as described in clause 40, wherein the actuator assembly 80 comprises one or more strips of piezoelectric material 82 and a substrate 83, and the two or more liquid manifolds 101, 102 comprise one or more notches 81 in either the substrate 83 and / or the one or more strips of piezoelectric material 82.

[0173] 42. An actuator component 100-1000 as described in clause 40 or clause 41, wherein the actuator assembly 80 comprises a plurality of thermal control fluid flow paths 231T arranged in a thermal control fluid flow path array 230T extending in an array direction 10, and wherein, in use, the thermal control fluid flowing through the thermal control fluid flow paths 231T controls the thermal properties of the liquid flowing through the liquid chamber 131, thereby controlling the thermal properties of the liquid ejected from the droplet ejection nozzle 121.

Claims

1. An actuator component for a droplet ejection head, an actuator assembly and a nozzle plate; the actuator assembly comprising a plurality of liquid chambers arranged in an array of liquid chambers extending in an array direction; the plurality of liquid chambers are arranged to be fluidly connectable to a liquid supply; the actuator component for the droplet ejection head includes a plurality of gas channels arranged in an array of gas channels extending in the array direction; the plurality of gas flow paths are arranged to be fluidly connectable to a gas supply source; the array of liquid chambers and the array of gas channels are fluidly independent of one another; the nozzle plate having a plurality of droplet ejection nozzles arranged in an array of nozzles extending in the array direction; and a plurality of gas orifices arranged in an array of orifices extending in the array direction; the gas orifices and the droplet ejection nozzles are arranged in a repeating pattern extending in the array direction; each liquid chamber fluidly connected to one or more of the droplet ejection nozzles and arranged to be actuatable to eject droplets of liquid; the plurality of gas passages are arranged to be fluidly connected to respective one or more gas orifices for passing gas therethrough; An actuator component for a droplet ejection head, wherein the actuator component is configured such that, in use, gas flowing through the gas orifice controls one or more properties of the liquid ejected from the droplet ejection nozzle.

2. The actuator component for a droplet ejection head according to claim 1 , wherein the gas orifice has an elongated shape.

3. The actuator component for a droplet ejection head according to claim 1 , wherein the gas orifice has substantially the same shape as the droplet ejection nozzle.

4. 4. The actuator component for a droplet ejection head according to claim 1, wherein each droplet ejection nozzle is provided with a plurality of gas orifices.

5. 5. The actuator component for a droplet ejection head according to claim 4, wherein the plurality of gas orifices provided for each droplet ejection nozzle are spaced apart from the center of the nozzle in the array direction.

6. 6. The actuator component for a droplet ejection head according to claim 4, wherein the plurality of gas orifices provided for each droplet ejection nozzle are spaced apart from the center of the nozzle in the extension direction of the liquid chamber.

7. An actuator component for a droplet ejection head as described in any one of claims 1 to 6, wherein one or more droplet ejection nozzles have at least two gas orifices spaced apart from the center of the nozzle in the array direction for each droplet ejection nozzle, and at least two gas orifices spaced apart from the center of the nozzle in the extension direction of the liquid chamber for each droplet ejection nozzle, and the droplet ejection nozzle is substantially surrounded by the gas orifices.

8. 8. An actuator component for a droplet ejection head according to claim 1, wherein the centers of substantially all of the gas orifices are spaced apart from the center of the nearest droplet ejection nozzle in the array direction by a nozzle pitch ns / 2.

9. The actuator component for a droplet ejection head according to claim 1 , wherein the liquid chamber is elongated in a direction not parallel to the array direction.

10. 10. An actuator component for a droplet ejection head according to claim 1, wherein the gas flow path is elongated in a direction not parallel to the array direction.

11. 11. An actuator component for a droplet ejection head according to claim 1, wherein the gas flow path is deeper than the liquid chamber in the height direction of the liquid chamber in order to achieve the fluid independence.

12. The actuator component for a droplet ejection head according to claim 1 , wherein the liquid chamber and the gas flow path are arranged parallel to each other.

13. The actuator component for a droplet ejection head according to claim 1 , wherein the gas flow paths and the liquid chambers are arranged in a staggered manner so as to extend in the array direction.

14. 14. An actuator component for a droplet ejection head according to claim 1, wherein the liquid chambers comprise an actuator associated with each liquid chamber and operable to eject droplets through the one or more droplet ejection nozzles.

15. An actuator component for a droplet ejection head according to any preceding claim, wherein one or more walls of the liquid chamber are actuatable to eject droplets of liquid through the one or more droplet ejection nozzles.

16. An actuator component for a droplet ejection head as described in any preceding claim, further comprising one or more gas manifolds, the gas flow path being fluidly connectable to the gas supply source via the one or more gas manifolds.

17. 17. An actuator component for a droplet ejection head according to claim 1, wherein the gas flow path comprises a driving electrode / electrical wiring.

18. 18. An actuator component for a droplet ejection head according to claim 1, wherein the gas flow passages are narrower in the array direction than the liquid chambers.

19. A droplet ejection head comprising one or more actuator components according to any one of claims 1 to 18.

20. 20. A droplet ejection device comprising one or more actuator components according to any one of claims 1 to 18, or one or more droplet ejection heads according to claim 19, and further comprising a liquid supply source and a gas supply source, wherein the gas supply source can be arranged to be a positive pressure or a negative pressure gas supply source.

21. 21. A method of operating the droplet ejection device of claim 20, comprising: ejecting droplets of liquid from one or more of the droplet ejection nozzles in accordance with a printing instruction; and flowing a gas through the gas orifice to control the droplets of the liquid ejected from the droplet ejection nozzle.

22. 22. The method of claim 21, further comprising positioning the gas source to be a negative pressure gas source to draw gas through the gas orifice and into the actuator component.

23. 22. The method of claim 21, further comprising: positioning the gas source to be a positive pressure gas source to supply gas to the actuator component for flowing gas from the actuator component through the gas orifice.

24. 24. The method of any of claims 21 to 23, wherein the liquid is a droplet ejection liquid.

25. 25. The method of any of claims 21 to 24, wherein droplet composition is controlled by interaction with gas flowing through the gas orifice.

26. 26. The method of any one of claims 21 to 25, wherein the gas comprises one or more of atmospheric air, air heated to a temperature above ambient temperature or air cooled to a temperature below ambient temperature, humid air having a humidity above ambient, dehumidified air having a humidity below ambient, an inert gas, a solvent used as a component of the gaseous liquid.

27. 27. The method of any of claims 21 to 26, wherein flowing the gas through the gas orifice is substantially continuous.

28. 28. The method of any of claims 21 to 27, wherein droplet ejection velocity is controlled as a function of gas velocity flowing through the gas orifice.

29. 29. The method of any of claims 21 to 28, wherein the velocity of the gas as it flows through the gas orifice is adjusted as a function of droplet ejection velocity.

30. 30. The method of any of claims 21 to 29, wherein the gas velocity as it flows through the gas orifice is greater than the droplet ejection velocity.

31. 1. A method for manufacturing an actuator component for a droplet ejection head, comprising: The method includes forming an actuator assembly; forming the actuator assembly includes forming one or more arrays of liquid chambers in one or more strips of piezoelectric material extending in an array direction; forming one or more arrays of liquid chambers in the strip of piezoelectric material, each of said liquid chambers forming an open channel that is open in the height direction of the liquid chamber and open at both ends in the direction of extension of the liquid chamber; forming one or more arrays of gas channels in the one or more strips of piezoelectric material extending in the array direction; each of the gas flow paths forms an open flow path in the strip of piezoelectric material in the height direction of the liquid chamber and open at both ends in the extension direction of the liquid chamber; the array of liquid chambers and the array of gas channels form one or more arrays of gas channels that are fluidly independent of one another; The method includes fixedly attaching a nozzle plate to the actuator assembly; The method includes forming a droplet ejection nozzle and a gas orifice in the nozzle plate, either before or after the step of fixedly attaching the nozzle plate to the actuator assembly, such that, when assembled, the actuator component comprises a droplet ejection nozzle fluidly connected to the liquid chamber and a gas orifice fluidly connected to the gas flow path; the gas orifices and the droplet ejection nozzles are arranged in a repeating pattern extending in the array direction.

32. 32. The manufacturing method of claim 31 , wherein fixedly attaching the nozzle plate includes attaching the nozzle plate to the strip of piezoelectric material at one end in an extension direction of the liquid chamber such that the nozzle plate acts to fluidly seal the gas flow path and the liquid chamber in the extension direction of the liquid chamber.

33. fixedly attaching a cover portion to each of the one or more strips of piezoelectric material at an end of the liquid chamber opposite the nozzle plate; 33. The method of claim 32, further comprising selectively forming a plurality of apertures in the cover portion, the cover portion comprising at least one opening per liquid chamber across a substantial portion of the array of liquid chambers.

34. 32. The method of claim 31 , wherein fixedly attaching the nozzle plate comprises attaching the nozzle plate to the strip of piezoelectric material in a height direction of the liquid chamber such that the nozzle plate acts to fluidly seal the gas flow path and the liquid chamber in the height direction of the liquid chamber.

35. fixedly attaching a first cover portion to each of the one or more strips of piezoelectric material in an extension direction of the liquid chamber; 35. The method of claim 34, further comprising selectively forming a plurality of apertures in the one or more cover portions, the cover portions comprising at least one aperture per liquid chamber across a substantial portion of the array of liquid chambers.

36. fixedly attaching a second cover portion to each of the one or more strips of piezoelectric material at an end opposite the first cover portion in an extension direction of the liquid chamber; 36. The manufacturing method of claim 35, further comprising forming a plurality of apertures in the second cover portion such that the plurality of liquid chambers have at least one aperture at each end in an extension direction of the liquid chambers.

37. forming one or more notches in either the substrate and / or the strip of piezoelectric material; fixedly attaching the one or more strips of piezoelectric material to the substrate such that each of the one or more notches is located proximate an interface between the substrate and a respective strip of piezoelectric material to form one or more gas manifolds; 37. The method of any of claims 31 to 36, further comprising: each of the one or more arrays of liquid chambers being fluidly isolated from the one or more gas manifolds; and each of the one or more arrays of gas flow paths being fluidly connected to at least one of the one or more gas manifolds.

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