Fluid ejection methods with reduced crosstalk

Abstract

To stabilize the drop size and velocity of fluid ejected from each fluid ejector and enable precise and accurate printing.SOLUTION: A fluid ejection apparatus includes a plurality of fluid ejectors. Each fluid ejector includes a pumping chamber, and an actuator configured to cause fluid to be ejected from the pumping chamber. The fluid ejection apparatus includes a feed channel fluidically connected to each pumping chamber; and at least one compliant structure formed in a surface of the feed channel. The at least one compliant structure has a lower compliance than the surface of the feed channel.SELECTED DRAWING: Figure 1

Description

Related Applications

[0001] This application is a divisional application claiming the benefit of priority under 35 U.S.C. § 120 from U.S. Provisional Patent Application No. 14 / 695,525, filed on April 24, 2015, which has been nationalized in Japan as Japanese Patent Application No. 2017-555,323 (International Filing Date: April 13, 2016), and is also a divisional application claiming the benefit of priority from a divisional application filed on June 24, 2021 (Japanese Patent Application No. 2021-104,762), and further a divisional application claiming the benefit of priority from a divisional application filed on April 7, 2023 (Japanese Patent Application No. 2023-062,693).

Technical Field

[0002] The present disclosure generally relates to fluid ejection devices.

Background Art

[0003] In some fluid ejection devices, fluid droplets are ejected onto a medium from one or more nozzles. The nozzles are fluidly connected to a fluid path that includes a fluid pumping chamber. The fluid pumping chamber can be actuated by an actuator that causes the ejection of fluid droplets. The medium can be moved relative to the fluid ejection device. The ejection of fluid droplets from a particular nozzle is timed with the movement of the medium to place the fluid droplets at a desired location on the medium. The ejection of fluid droplets of uniform size and velocity in the same direction enables the uniform deposition of the fluid droplets on the medium.

Summary of the Invention

Means for Solving the Problems

[0004] When an actuator of a fluid ejector is activated, pressure fluctuations can propagate into the inlet and outlet feed channels connected from the pumping chamber. These pressure fluctuations can propagate into other fluid ejectors connected to the same inlet or outlet feed channel. This fluid crosstalk can have an adverse effect on print quality.

[0005] To mitigate the propagation of pressure fluctuations, compliant microstructures can be formed within one or more surfaces of the inlet feed channel, the outlet feed channel, or both. The presence of compliant microstructures within the feed channel increases the compliance available at the surface of the feed channel and attenuates the pressure fluctuations that occur within that feed channel. In some embodiments, the compliant microstructures include indentations formed within the bottom surface of the feed channel. A membrane covers the indentation and deflects into the indentation in response to an increase in pressure within the feed channel, thus attenuating the pressure fluctuations. In some embodiments, the compliant microstructures include nozzle-like structures formed within the bottom surface of the feed channel. When the pressure within the feed channel increases, the meniscus at the outward-facing opening of each nozzle-like structure can attenuate the pressure fluctuations. The presence of such compliant microstructures thus reduces fluid crosstalk between fluid ejectors connected to the same inlet or outlet feed channel, and thus stabilizes the droplet size and velocity of the fluid ejected from each fluid ejector, enabling precise and accurate printing.

[0006] In a general aspect, a fluid ejection device includes a plurality of fluid ejectors. Each fluid ejector includes a pumping chamber and an actuator configured to eject fluid from the pumping chamber. The fluid ejection device includes a feed channel fluidly connected to each pumping chamber and at least one compliant structure formed within the surface of the feed channel. The at least one compliant structure has a lower compliance than the surface of the feed channel.

[0007] Embodiments can include one or more of the following features.

[0008] At least one compliant structure comprises a plurality of indentations formed within the surface of the feed channel and a membrane disposed across the indentations. In some cases, the membrane seals the indentations. In some cases, the depth of each indentation is less than the thickness of the surface of the feed channel. In some cases, the membrane is configured to deflect into the indentation in response to an increase in fluid pressure within the feed channel. In some cases, the indentation is formed within one or more than one of the bottom wall or the top wall of the feed channel. In some cases, the indentation is formed within the side wall of the feed channel.

[0009] At least one compliant structure comprises one or more than one dummy nozzle formed within the surface of the feed channel. In some cases, each dummy nozzle includes a first opening on the inner surface of the surface and a second opening on the outer surface of the surface. In some cases, a convex meniscus is formed at the second opening in response to an increase in fluid pressure within the feed channel. In some cases, each fluid ejector includes a nozzle formed within a nozzle layer, and the dummy nozzle is formed within the nozzle layer. In some cases, the dummy nozzle is substantially the same size as the nozzle.

[0010] Each fluid ejector includes a nozzle formed within a nozzle layer, and the nozzle layer constitutes the surface of the feed channel.

[0011] Each fluid ejector includes an actuator and a nozzle, and the actuation of one of the actuators causes fluid to be ejected from the corresponding nozzle. In some cases, the actuation of one of the actuators causes a change in fluid pressure within the feed channel, and at least one compliant structure is configured to at least partially attenuate the change in fluid pressure within the feed channel.

[0012] Generally, the method includes forming a plurality of nozzles within a nozzle layer, forming at least one compliant structure within the nozzle layer, wherein the at least one compliant structure has a lower compliance than the nozzle layer, and attaching the nozzle layer to a substrate comprising a plurality of fluid ejectors, wherein each fluid ejector comprises a pumping chamber and an actuator configured to eject fluid from the pumping chamber.

[0013] Embodiments can include one or more of the following features.

[0014] Forming at least one compliant structure within the nozzle layer includes forming a plurality of depressions within the nozzle layer and disposing a membrane across the depressions. In some cases, disposing a membrane across the depressions includes depositing a membrane layer across an upper surface of the nozzle layer and removing a portion of the membrane layer across each nozzle.

[0015] Forming a plurality of nozzles includes forming a plurality of nozzles within a first layer, and forming at least one compliant structure includes forming at least one compliant structure within a second layer and attaching the first layer to the second layer.

[0016] Forming at least one compliant structure within the nozzle layer includes forming at least one compliant structure within a first layer and attaching the first layer to a second layer having a plurality of nozzles formed therein, wherein both the first layer and the second layer form the nozzle layer.

[0017] Forming at least one compliant structure within the nozzle layer includes forming one or more dummy nozzles within the nozzle layer.

[0018] In a general aspect, the method includes the step of operating a fluid ejector within a fluid ejection device. Operating the fluid ejector creates a change in fluid pressure within a feed channel that is fluidly connected to the fluid ejector. The method includes the step of deflecting a membrane into a recess formed within the surface of the feed channel in response to the change in fluid pressure within the feed channel.

[0019] Embodiments can include one or more of the following features.

[0020] The step of deflecting the membrane into the recess includes the step of reverse deflecting the membrane.

[0021] The approach described herein can have one or more of the following advantages. The presence of compliant microstructures such as recesses within the surface of the feed channel or dummy nozzles can mitigate fluid crosstalk between fluid ejectors fluidly connected to that feed channel. For example, the compliant microstructures can increase the compliance available at the surface of the feed channel and thus enable the energy from pressure fluctuations generated by the actuation of an actuator within the fluid ejector to be attenuated. As a result, the influence of pressure fluctuations reaching other fluid ejectors connected to that feed channel can be reduced. By reducing fluid crosstalk between fluid ejectors within a printhead, the droplet size and velocity of the fluid ejected from the fluid ejectors can be stabilized and thus enable precise and accurate printing.

[0022] Details of one or more embodiments are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will be apparent from the description, drawings, and claims.

Brief Description of the Drawings

[0023]

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[0024] Like reference numerals and symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Referring to FIG. 1, a printhead 100 can be used to eject droplets of a fluid such as ink, a biological liquid, a polymer, a liquid for forming electronic components, or other types of fluids onto a surface. The printhead 100 includes, for example, a casing 410 with an internal volume that is divided into a fluid supply chamber 432 and a fluid return chamber 436 by an upper divider 530 and a lower divider 440.

[0026] The bottoms of the fluid supply chamber 432 and the fluid return chamber 436 are defined by the upper surface of an interposer assembly. The interposer assembly can be attached to the lower printhead casing 410 by bonding, friction, or another attachment mechanism, etc. The interposer assembly can include an upper interposer 420 and a lower interposer 430 positioned between the upper interposer 420 and the substrate 110.

[0027] The upper interposer 420 includes a fluid supply inlet 422 and a fluid return outlet 428. For example, the fluid supply inlet 422 and the fluid return outlet 428 can be formed as openings within the upper interposer 420. The flow path 474 is formed within the upper interposer 420, the lower interposer 430, and the substrate 110. Fluid can flow along the flow path 474 from the supply chamber 432 into the fluid supply inlet 422 and to one or more fluid ejection devices (described in more detail below) for ejection from the print head 100. Fluid can also flow along the flow path 474 from one or more fluid ejection devices into the fluid return outlet 428 and into the return chamber 436. In FIG. 1, a single flow path 474 is shown as a straight passage for illustrative purposes. However, the print head 100 can include multiple flow paths 474, and the flow paths 474 are not necessarily straight.

[0028] Referring to FIGS. 2 and 3, the substrate 110 can be a monolithic semiconductor body such as a silicon substrate. The passages through the substrate 110 define flow paths for fluid through the substrate 110. In particular, the substrate inlet 12 receives fluid from the supply chamber 432, extends through a membrane 66 (discussed in more detail below), and supplies the fluid to one or more inlet feed channels 14. Each inlet feed channel 14 supplies fluid to a plurality of fluid ejectors 150 through corresponding inlet passages (not shown). For convenience, only one fluid ejector 150 is shown in FIGS. 2 and 3. Each fluid ejector includes a nozzle 22 formed within a nozzle layer 11 disposed on the bottom surface of the substrate 110. In some embodiments, the nozzle layer 11 is an integral part of the substrate 110. In some embodiments, the nozzle layer 11 is a layer deposited on the surface of the substrate 110. Fluid can be selectively ejected from the nozzles 22 of one or more of the fluid ejectors 150 and printed onto a surface.

[0029] The fluid flows along the ejector flow path 475 through each fluid ejector 150. The ejector flow path 475 can include a pumping chamber inlet passage 17, a pumping chamber 18, a descender 20, and an outlet passage 26. The pumping chamber inlet passage 17 fluidly connects the pumping chamber 18 to the inlet feed channel 14 and can include, for example, an ascender 16 and a pumping chamber inlet 15. The descender 20 is fluidly connected to a corresponding nozzle 22. The outlet passage 26 connects the descender 20 to an outlet feed channel 28 that fluidly connects the descender 20 to a return chamber 436 through a substrate outlet (not shown).

[0030] In the embodiments of FIGS. 2 and 3, passages such as the substrate inlet 12, the inlet feed channel 14, and the outlet feed channel 28 are shown in a common plane. In some embodiments (e.g., in the embodiments of FIGS. 3A and 3B), one or more of the substrate inlet 12, the inlet feed channel 14, and the outlet feed channel 28 are not in a common plane with the other passages.

[0031] Referring to FIGS. 4A and 4B, the substrate 110 includes a plurality of inlet feed channels 14 formed therein and extending parallel to each other. Each inlet feed channel 14 fluidly communicates with at least one substrate inlet 12 extending perpendicular to the inlet feed channel 14. The substrate 110 also includes a plurality of outlet feed channels 28 formed therein and extending parallel to each other. Each outlet feed channel 28 fluidly communicates with at least one substrate outlet (not shown) extending perpendicular to the outlet feed channel 28. In some embodiments, the inlet feed channels 14 and the outlet feed channels 28 are arranged in an alternating row.

[0032] The substrate includes a plurality of fluid ejectors 150. The fluid flows along a corresponding ejector flow path 475 that includes an ascender 16, a pumping chamber inlet 15, a pumping chamber 18, and a descender 20 through each fluid ejector 150. Each ascender 16 is fluidly connected to one of the inlet feed channels 14. Each ascender 16 is also fluidly connected to a corresponding pumping chamber 18 through the pumping chamber inlet 15. The pumping chamber 18 is fluidly connected to a corresponding descender 20 that leads to an associated nozzle 22. Each descender 20 is also connected to one of the outlet feed channels 28 through a corresponding outlet passage 26. For example, a cross-sectional view of the fluid ejector of FIG. 3 is obtained along line 2-2 of FIG. 4A.

[0033] The specific flow path configurations described herein are examples of flow path configurations. The approaches described herein can also be used in other flow path configurations.

[0034] In some embodiments, the printhead 100 includes a plurality of nozzles 22 arranged in parallel rows 23. All of the nozzles 22 within a given row 23 can be fluidly connected to the same inlet feed channel 14 and the same outlet feed channel 28. That is, for example, all of the ascenders 16 within a given row can be connected to the same inlet feed channel 14, and all of the descenders within a given row can be connected to the same outlet feed channel 28.

[0035] In some embodiments, all of the nozzles 22 within an adjacent column can be fluidly connected to the same inlet feed channel 14 or the same outlet feed channel 28, but not both. For example, in the embodiment of FIG. 4A, each nozzle 22 within column 23a is fluidly connected to inlet feed channel 14a and outlet feed channel 28a. The nozzles 22 within the adjacent column 23b are also connected to the inlet feed channel 14a, but not to the outlet feed channel 28b. In some embodiments, the columns of nozzles 22 can be connected to the same inlet feed channel 14 or the same outlet feed channel 28 in an alternating pattern. Further details regarding the print head 100 can be found in U.S. Patent No. 7,566,118, the content of which is incorporated herein by reference in its entirety.

[0036] Referring again to FIG. 2, each fluid ejector 150 includes a corresponding actuator 30, such as a piezoelectric transducer or a resistive heater. The pumping chamber 18 of each fluid ejector 150 is in close proximity to the corresponding actuator 30. Each actuator 30 is selectively actuated to pressurize the corresponding pumping chamber 18 and thus eject fluid from the nozzle 22 connected to the pressurized pumping chamber.

[0037] In some embodiments, the actuator 30 can include a piezoelectric layer 31, such as a layer of lead zirconate titanate (PZT). The piezoelectric layer 31 can have a thickness of about 50 μm or less, for example, from about 1 μm to about 25 μm, for example, from about 2 μm to about 5 μm. In the embodiment of FIG. 2, the piezoelectric layer 31 is continuous. In some embodiments, the piezoelectric layer 31 can be made discontinuously during processing, for example, by an etching or sawing step. The piezoelectric layer 31 is sandwiched between a drive electrode 64 and a ground electrode 65. The drive electrode 64 and the ground electrode 65 can be metals such as copper, gold, tungsten, indium tin oxide (ITO), titanium, platinum, or a combination of metals. The thicknesses of the drive electrode 64 and the ground electrode 65 can be, for example, about 2 μm or less, for example, about 0.5 μm.

[0038] The membrane 66 is disposed between the actuator 30 and the pumping chamber 18, isolating the ground electrode 65 from the fluid within the pumping chamber 18. In some embodiments, the membrane 66 is a separate layer. In some embodiments, the membrane is integral with the substrate 110. In some embodiments, the actuator 30 does not include the membrane 66, and the ground electrode 65 is formed on the back side of the piezoelectric layer 31 such that the piezoelectric layer 31 is directly exposed to the fluid within the pumping chamber 18.

[0039] To operate the piezoelectric actuator 30, an electrical voltage is applied between the drive electrode 64 and the ground electrode 65, enabling the voltage to be applied to the piezoelectric layer 31. The applied voltage deflects the piezoelectric layer 31, which in turn deflects the membrane 66. The deflection of the membrane 66 causes a change in volume within the pumping chamber 18, generating a pressure pulse (also referred to as an emission pulse) within the pumping chamber 18. The pressure pulse propagates through the descender 20 to the corresponding nozzle 22, thus causing droplets of fluid to be ejected from the nozzle 22.

[0040] The membrane 66 can be formed from silicon (e.g., single crystal silicon), a single layer of another semiconductor material, an oxide such as aluminum oxide (AlO2) or zirconium oxide (ZrO2), glass, aluminum nitride, silicon carbide, one or more layers of other ceramics or metals, silicon on insulator, or other materials. For example, the membrane 66 can be formed from an inert material having a compliance such that actuation of the actuator 30 causes sufficient flexure of the membrane 66 to eject droplets of fluid. In some embodiments, the membrane 66 can be affixed to the actuator 30 using an adhesive layer 67. In some embodiments, two or more of the substrate 110, the nozzle layer 11, and the membrane 66 can be formed as an integral body.

[0041] In some cases, when one of the actuators 30 of the fluid ejector 150 is actuated, pressure fluctuations can propagate into the inlet feed channel 14 through the ascender 16 of the fluid ejector 150. Similarly, energy from the pressure fluctuations can also propagate into the outlet feed channel 28 through the descender 20 of the fluid ejector 150. In some cases, this application generally refers to the inlet feed channel 14 and the outlet feed channel 28 as the feed channels 14, 28. Pressure fluctuations can thus occur in one or more of the feed channels 14, 28 connected to the actuated fluid ejector 150. In some cases, these pressure fluctuations can propagate into the ejector flow paths 475 of other fluid ejectors 150 connected to the same feed channels 14, 28. These pressure fluctuations can affect the droplet volume and / or droplet velocity of the droplets ejected from those fluid ejectors 150 and can degrade the print quality. For example, fluctuations in droplet volume can vary the amount of fluid ejected, and fluctuations in droplet velocity can vary the location where the ejected droplets are deposited on the print surface. The induction of pressure fluctuations within a fluid ejector is referred to as fluid crosstalk.

[0042] In some embodiments, fluid crosstalk can be caused by slow dissipation of pressure fluctuations within the feed channels 14, 28. In some embodiments, fluid crosstalk can be caused by standing waves that occur within the feed channels 14, 28. For example, when one of the actuators 30 of the fluid ejector 150 is actuated, the pressure fluctuations propagating through the feed channels 14, 28 can occur within a standing wave. When fluid ejection occurs at a frequency that enhances the standing wave, the standing wave within the feed channels 14, 28 can propagate pressure oscillations into the ejector flow paths 475 of other fluid ejectors 150 connected to the same feed channels 14, 28, causing fluid crosstalk between those fluid ejectors 150.

[0043] Fluid crosstalk can also occur due to abrupt changes in the fluid flowing through the feed channels 14, 28. Generally, when a fluid moving within a flow channel is suddenly forced to stop or change direction, a pressure wave can propagate within the flow channel (also referred to as the "water hammer" effect). For example, if one or more fluid ejectors 150 connected to the same feed channels 14, 28 are suddenly turned off, the water hammer effect will propagate pressure waves into the flow channels 14, 28. That pressure wave can further propagate into the ejector flow paths 475 of other fluid ejectors 150 connected to the same feed channels 14, 28, and can cause fluid crosstalk between those fluid ejectors 150.

[0044] Fluid crosstalk can be reduced by providing better compliance within the fluid ejector and attenuating pressure fluctuations. By increasing the compliance available in the fluid ejector, the energy from the pressure fluctuations generated within one of the fluid ejectors is attenuated, and thus the impact of the pressure fluctuations reaching neighboring fluid ejectors can be reduced.

[0045] Compliance within the fluid ejector and its associated fluid flow paths is available in the fluid, the meniscus in the nozzle, and the surfaces of the fluid flow paths (e.g., the inlet feed channels 14, the pump chamber inlet passage 17, the descender 20, the outlet passage 26, the outlet feed channels 28, and other fluid flow paths).

[0046] The compliance of the fluid in the feed channel is given by the following.

[0047]

Equation

[0048] Where V is the volume of the fluid in the feed channel and B is the bulk modulus of the fluid.

[0049] The compliance of a single meniscus is given by the following.

[0050] [Number]

[0051] In the formula, r is the radius of the meniscus, and σ is the surface tension.

[0052] The compliance of a rectangular surface (such as the surface of an inlet or outlet feed channel) is given by the following (for the case of fixed end conditions).

[0053] [Number]

[0054] In the formula, l, w, and t w are the length, width, and thickness of the surface, respectively. Each surface of the inlet and outlet feed channels has a certain degree of compliance. In some fluid ejectors, the most compliant surface of the feed channel is the bottom surface formed by the silicon nozzle layer 11.

[0055] In one specific embodiment, the print head has feed channels (e.g., inlet feed channel 14 or outlet feed channel 28) that supply 16 fluid ejectors (thus, there are 16 menisci associated with the feed channels). The feed channels have a width of 0.39 mm, a depth of 0.27 mm, and a length of 6 mm. The thickness of the silicon nozzle layer 11 is 30 μm, and the elastic modulus of the nozzle layer is 186 E9 Pa. The radius of each meniscus is 7 μm. The typical bulk elastic modulus for an aqueous ink is approximately B = 2 E9 Pa, and the typical surface tension is approximately 0.035 N / m.

[0056] Regarding this embodiment, the compliance of the fluid in the feed channel, the 16 menisci, and the nozzle layer in the feed channel is given in Table 1. It should be noted that the nozzle layer in the feed channel has the lowest compliance.

[0057] [Table 1]

[0058] Table 1. Fluids in the delivery channel, menisci of 16 nozzles delivered by the delivery channel, and compliance values of the nozzle layer of the delivery channel.

[0059] An increase in compliance within fluid ejector 150 and its associated fluid flow path can help mitigate fluid crosstalk between fluid ejectors 150. By increasing the available compliance, the propagation of pressure fluctuations from a particular fluid ejector 150 to neighboring fluid ejectors 150 is attenuated within the fluid ejector 150 or the inlet and / or outlet delivery channels 14, 28 to which the fluid ejector 150 is connected, and thus the impact of such pressure fluctuations on other fluid ejectors 150 can be reduced. For example, the compliance of the delivery channels 14, 28 can be increased to mitigate fluid crosstalk between fluid ejectors 150 connected to those delivery channels 14, 28.

[0060] Referring again to FIG. 3, compliance can be added to the inlet feed channel 14, the outlet feed channel 28, or both by forming compliant microstructures 50 on one or more surfaces of the inlet feed channel 14 and / or the outlet feed channel 28. For example, in the embodiment of FIG. 3, the compliant microstructures 50 are formed within the bottom surface 52 of the inlet feed channel 14 and the bottom surface 54 of the outlet feed channel. In this embodiment, the bottom surfaces 52, 54 are formed by the nozzle layer 11. The additional compliance provided by the compliant microstructures 50 within the feed channels 14, 28 attenuates the energy from pressure fluctuations within a particular fluid ejector 150 connected to that feed channel 14, 28. As a result, the effect of that pressure fluctuation on other fluid ejectors 150 connected to the same feed channels 14, 28 can be reduced. Referring to FIGS. 5A and 5B, in some embodiments, the compliant microstructures 50 formed within the nozzle layer 11 of the inlet feed channel 14 and / or the outlet feed channel 28 can be depressions 500 covered by a thin film 502. The film 502 is disposed across the depression 500 such that the inner surface 504 of the nozzle layer 11 facing into the feed channels 14, 28 is substantially flat. In some cases, for example, when a vacuum exists within the depression 500, the film 502 can be slightly deflected into the depression 500. In some embodiments, the depression 500 can be formed within the nozzle layer 11, also referred to as the bottom wall of the inlet or outlet feed channel 14, 28. In some embodiments, the depression 500 can be formed within the upper wall of the inlet or outlet feed channel, which is the wall opposite the bottom wall. In some embodiments, the depression 500 can be formed within one or more side walls of the inlet or outlet feed channel 14, 28, which are walls that intersect the upper and bottom walls.

[0061] When pressure fluctuations propagate into the supply channels 14, 28, the membrane 502 deflects into the recess, attenuating the pressure fluctuations and reducing fluid crosstalk between adjacent fluid ejectors 150 connected to the supply channels 14, 28. The deflection of the membrane 502 is reversible such that when the fluid pressure in the supply channels 14, 28 is reduced, the membrane 502 returns to its original configuration.

[0062] The recess 500 can have a lateral dimension (e.g., radius) of from about 50 μm to about 150 μm, such as about 100 μm. For example, the lateral dimension of the recess 500 can be from about 10% to about 75% of the width of the supply channel surface, such as about 50% of the width of the supply channel surface. The recess 500 can have a depth of from about 5 μm to about 15 μm, such as about 6 - 10 μm. The recess 500 is provided at a density of from about 10 recesses / mm 2 to about 50 recesses / mm 2 , such as about 20 recesses / mm 2 . In the embodiments of FIGS. 5A and 5B, the recess 500 is circular. In some embodiments, the recess 500 can be other shapes, such as oval, elliptical, or other shapes. For example, the recess 500 can be shaped such that there are no sharp corners where mechanical stress can concentrate. The recesses 500 can be positioned in an aligned array, such as in rows and columns, but this is not necessary. For example, the recesses 500 can be randomly distributed.

[0063] In some embodiments, the membrane 502 can be formed from silicon. In some embodiments, the membrane 502 can be formed from an oxide such as SiO2. In some embodiments, the membrane 502 can be formed from a metal, e.g., a sputtered metal layer. Generally, the membrane 502 is thin enough to be able to deflect in response to pressure fluctuations within the feed channels 14, 28. Additionally, the membrane 502 is thick enough to be durable. The overall elastic modulus of the membrane 502 should be sufficient such that the membrane will not deflect to the bottom 506 of the recess 500 under the expected pressure fluctuations during operation; otherwise, the membrane 502 could break or bond to the bottom 506 of the recess 500. For example, the membrane can have a thickness of from about 0.5 μm to about 5 μm, e.g., about 1 μm, about 2 μm, or about 3 μm.

[0064] The presence of the plurality of recesses 500 within each of the feed channels 14, 28 can help ensure that the compliance of the nozzle layer 11 within the feed channels 14, 28 can be reduced even if one or more membranes 502 fail (e.g., by breaking or bonding to the bottom 506 of the recess 500).

[0065] The membrane 502 can seal the recess 500 against fluids such as liquids (e.g., ink) and gases (e.g., air). In some embodiments, the recess 500 is vented during processing and then sealed such that a desired pressure, e.g., atmospheric pressure (atm), 1 / 2 atm, or another pressure, is achieved within the recess. In some embodiments, the recess 500 is not vented such that a vacuum exists within the recess. The presence of a vacuum within the recess 500 can increase the stress on the membrane 502 and can reduce the additional compliance provided by the recess 500.

[0066] The compliance of the nozzle layer 11 within a feed channel, including 48 recesses, can be calculated as follows.

[0067]

Equation

[0068] In the formula, N is the number of depressions, a is the radius of each depression. D is given by the following.

[0069]

Number

[0070] In the formula, E is the elastic modulus of the film, t m is the thickness of the film, and ν is the Poisson's ratio of the film.

[0071] The central deflection of the film can be calculated by the following.

[0072]

Number

[0073] In the formula, q is the design pressure load of the film. This central deflection formula is applicable for small deflections, for example, for deflections up to approximately 5% of the maximum film thickness. In some embodiments, larger deflections may deviate from this formula. For example, the exemplary film 502 with a thickness of 2 μm deflects 3.2 μm and is 3.5 times stiffer than predicted by this formula.

[0074] The tensile stress in the film 502 can be calculated by the following.

[0075]

Number

[0076] In one specific embodiment, 48 indentations with a radius of 100 μm are formed in the nozzle layer 11 within the feed channels 14, 28 such that they have the dimensions and elastic modulus given above. The film 502 covering the indentations is formed from SiO2 thermal oxide and has a thickness of 2.0 μm, an elastic modulus of 75 E9 Pa, and a Poisson's ratio of 0.17. The indentations 500 are not vented. The design pressure load q is set at 150,000 Pa, taking into account 1 atm for the vacuum within the indentations and 0.5 atm for the purge pressure of the feed channels.

[0077] Regarding this embodiment, the compliance of the nozzle layer 11, the central deflection of the film 502, and the tensile stress within the film 502 are given in the first column of Table 2. Notably, the presence of the 48 indentations increased the compliance of the nozzle layer by approximately 9 times compared to a nozzle layer without indentations (discussed above and in Table 1).

[0078]

Table 2

[0079] Table 2. Compliance of the nozzle layer within the feed channels, central deflection of the film, and tensile stress within the film.

[0080] In some cases, the film 502 is deposited under compressive stress, which results in a central deflection y exceeding that given in Table 2 ccan be increased. For example, the central deflection of the membrane 502 can exceed half of the thickness of the membrane. In these situations, the stiffness of the membrane is increased and the stress for a given load is reduced (explained in more detail in Section 11.11 of Roark’ Formulas for Stress and Strain (7th Edition), the content of which is incorporated herein by reference in its entirety). For example, in the embodiment given above, the central deflection of the membrane is 2.3 times the thickness of the membrane. Thus, the stiffness of the membrane is increased 2.5 times. The compliance, central deflection, and tensile stress considering this increased stiffness are given in the second column of Table 2. The compliance of the nozzle layer with the recess is further increased 3.5 times compared to the nozzle layer without the recess.

[0081] These calculations show that the presence of the recess 500 in the nozzle layer 11 can significantly increase the compliance of the nozzle layer 11. The nozzle layer 11 having such a recess 500 can thus more effectively attenuate pressure fluctuations in the feed channels 14, 28 than a flat nozzle layer 11 and relieve fluid crosstalk between the fluid ejectors 150 connected to the feed channels 14, 28.

[0082] Figures 6A - 6F show one approach for fabricating the fluid ejector 150 having the recess 500 formed in the nozzle layer 11. Referring to FIGS. 6A and 7, the nozzle wafer 60 (e.g., a silicon wafer) includes a nozzle layer 11 (e.g., a silicon nozzle layer), an etching stop layer 62 (e.g., an oxide or nitride etching stop layer such as SiO2 or Si3N4), and a handle layer 64 (e.g., a silicon handle layer). In some embodiments, the nozzle wafer 60 does not include the etching stop layer 62. In some embodiments, the nozzle wafer 80 is a silicon-on-insulator (SOI) wafer, and the insulator layer of the SOI wafer acts as the etching stop layer 84.

[0083] The opening, which will provide the nozzle 22, is formed through the nozzle layer 11 using standard microfabrication techniques, including, for example, lithography and etching (700).

[0084] The recess 500, which extends partially rather than entirely through the nozzle layer 11, is also formed using standard microfabrication techniques, including, for example, lithography and etching (702). For example, a first layer of resist can be deposited on the unpatterned nozzle layer 11 and patterned by lithography. The nozzle layer 11 can be etched, for example, using deep reactive ion etching (DRIE) to form the nozzle 22. The first layer of resist can be removed, and a second layer of resist can then be deposited on the nozzle layer 11 and patterned by lithography. The nozzle layer 11 can be etched according to the patterned resist, for example, using wet etching or dry etching, to form the recess 500.

[0085] Referring to FIGS. 6B and 7, a second wafer 68 having a handle layer 69 and a membrane layer 70 that will provide the membrane 502 is bonded to the nozzle wafer 60. In particular, the membrane layer 70 is bonded to the nozzle layer 11 of the nozzle wafer 60 using, for example, thermal bonding or another wafer bonding technique (704). The layer membrane 70 can be an oxide (e.g., SiO2 thermal oxide).

[0086] Referring to FIGS. 6C and 7, the handle layer 69 is removed, for example, by grinding and polishing, wet etching, plasma etching, or another removal process, leaving the membrane layer 70. Referring to FIGS. 6D and 7, the membrane layer 70 is masked and etched using standard microfabrication techniques, including, for example, lithography and etching, to expose the nozzle 22 (708). The remaining portion of the membrane layer 70 forms the membrane 502 across the recess 500.

[0087] The patterned nozzle wafer 60, having the nozzles 22 and recesses 500 formed therein, can be further processed, for example, as described in U.S. Patent No. 7,566,118, the content of which is incorporated herein by reference in its entirety, to form the fluid ejectors 150 of the print head 100. Referring to FIGS. 6E and 7, in some embodiments, the upper surface 74 of the patterned nozzle wafer 60 can be joined (710) to a flow path wafer 76 having flow paths such as the descender 20 and other flow paths (not shown), an actuator (not shown), and other elements formed therein. For example, the upper surface 74 of the nozzle wafer 60 can be joined to the flow path wafer 76 using a low temperature joining such as joining using an epoxy (e.g., benzocyclobutene (BCB)), or using a low temperature plasma activated joining.

[0088] Referring to FIGS. 6F and 7, the handle layer 64 can then be removed (712), for example, by grinding and polishing, wet etching, plasma etching, or another removal process. The etch stop layer 62, if present, can be removed (as shown in FIG. 6F), or, for example, using standard microfabrication techniques including lithography and etching, either masked and etched or etched to expose the nozzles (714).

[0089] In some embodiments, a thick nozzle wafer 60 can be used (e.g., 30 μm, 50 μm, or 100 μm thick). The use of a thick nozzle wafer minimizes the risk that the nozzle processing process will thin the nozzle wafer until it becomes fragile.

[0090] Figures 8A - 8D illustrate another approach for fabricating a fluid ejector 150 having a recess 500 within a nozzle layer. Referring to FIGS. 8A and 9, a nozzle wafer 80 (e.g., a silicon wafer) includes a nozzle sub - layer 82 (e.g., a silicon nozzle sub - layer), an etch stop layer 84 (e.g., an oxide or nitride etch stop layer such as SiO2 or Si3N4), and a handle layer 86 (e.g., a silicon handle layer). In some embodiments, the nozzle wafer 80 does not include an etch stop layer 84. In some embodiments, the nozzle wafer 80 is a silicon - on - insulator (SOI) wafer, and the insulator layer of the SOI wafer acts as the etch stop layer 84.

[0091] Openings that would provide the nozzles 22 are formed (900) through the nozzle sub - layer 82 using standard microfabrication techniques, including, for example, lithography and etching.

[0092] Referring to FIGS. 8B and 9, a second wafer 86 includes an upper layer 88, an etch stop layer 90 (e.g., an oxide or nitride etch stop layer such as SiO2 or Si3N4), and a handle layer of silicon 92. The upper layer 88 can be formed from the same material (e.g., silicon) as the nozzle sub - layer 82. The recess 500 is etched (902) through, for example, the upper layer 88 of the SOI wafer 86 using standard microfabrication techniques, including, for example, lithography and etching. In some embodiments, the second wafer 86 is an SOI wafer, and the insulator layer of the SOI wafer acts as the etch stop layer 90.

[0093] Referring to FIGS. 8C and 9, the SOI wafer 86 is bonded to the nozzle wafer 80 (904), for example, using thermal bonding or another wafer bonding technique, such that the upper layer 88 of the SOI wafer 86 contacts the nozzle sub-layer 82 of the nozzle wafer 80. The recess 500 and the nozzle 22 are aligned, for example, by utilizing alignment targets (not shown) processed on the SOI wafer 86 as well as the nozzle wafer 80. For example, the alignment targets can include alignment indicators such as Vernier to indicate the amount of misalignment between the SOI wafer 86 and the nozzle wafer 80. In some embodiments, the SOI wafer 86 and the nozzle wafer 80 are aligned with an alignment tool that utilizes a camera such as an infrared camera to visually identify the alignment targets through the silicon wafer.

[0094] Referring to FIGS. 8D and 9, the handle layer 92 of the SOI wafer 86 is removed (906), for example, by grinding and polishing, wet etching, plasma etching, or another removal process. Referring to FIGS. 8E and 9, the insulator layer 90 and the upper layer 88 are masked and etched (908) using standard microfabrication techniques including, for example, lithography and etching, to expose the nozzle 22. The remaining insulator layer 88 forms a film 502 across the recess 500.

[0095] In the approach of FIGS. 8A - 8E, both the nozzle sub-layer 82 and the upper layer 88 together form the nozzle layer 11. The patterned nozzle wafer 80 can be further processed (910) to form the fluid ejector 150 of the print head, for example, as shown in FIGS. 6E and 6F and as described in U.S. Patent No. 7,566,118, the content of which is hereby incorporated by reference in its entirety.

[0096] Referring to FIG. 8F, in some embodiments, the recess 500 can be vented such that the air within the recess is at atmospheric pressure. To fabricate the vented recess, linear bore vents 95 are etched into the nozzle sublayer 82 of the nozzle wafer 80 prior to the bonding of the nozzle wafer 80 and the SOI wafer 86. The vents 95 are etched through the thickness of the nozzle sublayer 82 to the etch stop layer 84. The linear bore vents 95 are positioned such that when the nozzle wafer 80 is bonded to the SOI wafer 86, the vents 95 will be aligned with the recesses 500. When the nozzle 22 is opened by the removal of the handle layer 86 and the etch stop layer 84, the vents 95 will be open to the atmosphere and thus vent the interior space of the recesses 500.

[0097] Referring to FIG. 10, in some embodiments, compliant microstructures can be added to the sidewalls 172, 174 of the inlet feed channel 14 and / or the outlet feed channel 28. For example, one or more recess slots 170 can be formed adjacent to one or both of the sidewalls 172, 174, leaving a sidewall membrane 176 between the recess slot 170 and the interior of the feed channel 28. The sidewall membrane 176 can deflect into the recess slot 170 in response to pressure fluctuations and attenuate the pressure within the feed channels 14, 28. In some embodiments, the recess slots 170 can be formed by DRIE vertical etching of the substrate 110 prior to the bonding of the nozzle layer 11 to the substrate 110. In some embodiments, the recess slots 170 can be formed using anisotropic etching or DRIE etching such that they are tapered outwardly, and the etching is stopped by an etch stop layer such as a thermal oxide grown on the sidewalls 172, 174.

[0098] Referring to FIG. 11, in some embodiments, the compliant microstructures 50 (FIG. 3) formed within the nozzle layer 11 of the inlet feed channel 14 and / or the outlet feed channel 28 can be nozzle-like structures 120, which are also referred to herein as dummy nozzles 120. (For clarity, the nozzles 22 of the fluid ejector 150 are also referred to as firing nozzles.) The dummy nozzles 120 are located within the feed channels 14, 28, are not directly connected to or associated with any individual fluid ejector 150, and do not have corresponding actuators. The fluid pressure within the feed channels 14, 28 is generally not high enough to cause fluid to be ejected from the dummy nozzles 120 during normal operation. For example, the fluid ejector 150 can operate at a discharge pressure of several atmospheres (e.g., about 1 - 10 atm), and the threshold pressure for ejection can be about half of the operating pressure.

[0099] The dummy nozzles 120 extend through the entire thickness of the nozzle layer 11 and provide a free surface that increases the compliance of the nozzle layer 11. Each dummy nozzle 120 includes an inward-facing opening 122 on the inner surface 124 of the nozzle layer 11 and an outward-facing opening 126 on the outer surface 128 of the nozzle layer 11 (e.g., the surface facing the printing surface). A fluid meniscus 130 is formed at the outward-facing opening 126 of each dummy nozzle 120 (shown in FIG. 11 for only one dummy nozzle 120). In some examples, the feed channels 14, 28 are negatively pressurized such that, in the absence of pressure fluctuations, the meniscus 130 is drawn inwardly from the opening 126 (e.g., a concave meniscus). When pressure fluctuations propagate into the feed channels 14, 28, the meniscus 130 bulges (e.g., a convex meniscus), attenuates the pressure fluctuations, and alleviates fluid crosstalk between adjacent fluid ejectors 150 connected to the feed channels 14, 28.

[0100] In some embodiments, the dummy nozzle 120 is similar in size and / or shape to the ejection nozzle 22. For example, the dummy nozzle 120 can be a substantially cylindrical path with a constant diameter, and the inward-facing opening 122 and the outward-facing opening 126 have the same dimensions. The dummy nozzle 120 can also be a tapered conical path extending from a larger inward-facing opening 122 to a smaller outward-facing opening 126. The dummy nozzle 120 can also include a quadratic curve path extending from a larger inward-facing opening 122 to a smaller outward-facing opening 126. The dummy nozzle 120 can also include a plurality of cylindrical regions with diameters that gradually become smaller towards the outward-facing opening 126.

[0101] When the dummy nozzle 120 is similar in size to the ejection nozzle 22, the bubble pressures of the dummy nozzle 120 and the ejection nozzle 22 are also similar. However, since the fluid pressure is generally lower in the feed channels 14, 28 than in the fluid ejector 150, the fluid can be ejected from the ejection nozzle 22 without causing accidental discharge through the dummy nozzle 120. In some embodiments, the dummy nozzle 120 can have a size different from that of the ejection nozzle 22.

[0102] In some embodiments, the ratio of the thickness of the dummy nozzle 120 (e.g., the thickness of the nozzle layer 11) to the diameter of the outward-facing opening 128 can be about 0.5 or greater, for example, about 1 - 4, or about 1 - 2. For example, the radius of the outward-facing opening 128 can be about 5 μm to about 80 μm, for example, about 10 μm to about 50 μm. Regarding the tapered shape, the cone angle of the conical path of the dummy nozzle 120 can be, for example, about 5° to about 45°. Generally, the dummy nozzle 120 is small enough so that large contaminant particles that can clog the ejection nozzle 22 cannot enter the feed channels 14, 28 through the dummy nozzle 120.

[0103] In some embodiments, the print head 100 can be purged at a high fluid pressure, for example, to clean the fluid flow path. The high fluid pressure during purging can cause the fluid to be ejected from the dummy nozzles 120. To reduce fluid loss through the dummy nozzles 120 during such purging, a small number of dummy nozzles 120 can be formed within each feed channel 14, 28. For example, 1 to 20 dummy nozzles 120, such as about 1, 2, or 4 dummy nozzles per ejection nozzle, can be formed within each feed channel 14, 28. In some embodiments, the dummy nozzles 120 can be capped during purging so that little or no fluid is lost through the dummy nozzles 120.

[0104] FIG. 12 shows an exemplary approach for fabricating a fluid ejector 150 having dummy nozzles 120 formed within the nozzle layer 11. The nozzle wafer 140 includes the nozzle layer 11, an etching stop layer 142 (e.g., an oxide or nitride etching stop layer such as SiO2 or Si3N4), and a handle layer 124 (e.g., a silicon handle layer). In some embodiments, the nozzle wafer 120 does not include an etching stop layer 122.

[0105] The ejection nozzles and the dummy nozzles 120 are formed through the nozzle layer 11 using standard microfabrication techniques including, for example, lithography and etching. In some implementations, the ejection nozzles 22 and the dummy nozzles 120 are formed simultaneously within the nozzle layer 11 using, for example, the same etching step.

[0106] After the formation of the ejection nozzles 22 and the dummy nozzles 120, the processing can proceed substantially as illustrated and described with respect to FIGS. 6B - 6F, except that the dummy nozzles 120 replace the recesses 500.

[0107] Since the dummy nozzle 120 is formed during the processing steps that would occur to form the ejection nozzle 22, there is little impact on the cost associated with forming the dummy nozzle 120. In the illustrated embodiment, the ejection nozzle 22 and the dummy nozzle 120 are the same size. In some embodiments, the ejection nozzle 22 and the dummy nozzle 120 can have different sizes.

[0108] Certain embodiments have been described. Other embodiments are within the scope of the following claims.

[0109] Many changes and modifications can be made to the above-described embodiments of the present disclosure without substantially departing from the spirit and various principles of the present disclosure. All such modifications and changes are intended to be included within the scope of the present disclosure and protected by the following patent claims. For example, various features of the present disclosure may be combined according to the following embodiments.

[0110] Embodiment 1 A fluid ejection device, A plurality of fluid ejectors, each fluid ejector comprising A pumping chamber, A membrane defining the top wall of the pumping chamber, An actuator configured to eject fluid from the pumping chamber and disposed directly on the membrane, A nozzle, And a fluid ejector, A feed channel fluidly connected to each pumping chamber, At least one compliant structure formed within the surface of the feed channel, the at least one compliant structure being more compliant than the surface of the feed channel, Comprising, The at least one compliant structure comprises at least one dummy nozzle formed within the surface of the feed channel, Each dummy nozzle includes a first opening on an inner surface of the surface and a second opening on an outer surface of the surface. A fluid ejection device in which nozzles of the plurality of fluid ejectors are provided along a first line, and the supply channel is laterally offset from the first line.

[0111] Embodiment 2 The fluid ejection device according to Embodiment 1, wherein each actuator includes a piezoelectric layer disposed on the membrane.

[0112] Embodiment 3 The fluid ejection device according to Embodiment 1, wherein a convex meniscus is formed in the second opening in response to an increase in fluid pressure in the supply channel.

[0113] Embodiment 4 The fluid ejection device according to Embodiment 1, wherein nozzles of each fluid ejector are formed in a nozzle layer, and the dummy nozzles are formed in the nozzle layer.

[0114] Embodiment 5 The fluid ejection device according to Embodiment 1, wherein the dummy nozzles are substantially the same size as the nozzles.

[0115] Embodiment 6 The fluid ejection device according to Embodiment 1, wherein nozzles of each fluid ejector are formed in a nozzle layer, and the nozzle layer constitutes a surface of the supply channel.

[0116] Embodiment 7 In the fluid ejection device according to Embodiment 6, operation of one of the actuators causes a change in fluid pressure in the supply channel, and the at least one compliant structure is configured to at least partially attenuate the change in fluid pressure in the supply channel.

[0117] Embodiment 8 A method of manufacturing a fluid ejector, comprising: forming a plurality of nozzles in a nozzle layer; forming at least one compliant structure within the nozzle layer, the at least one compliant structure being more compliant than the nozzle layer; attaching the nozzle layer to a substrate comprising a plurality of fluid ejectors, each fluid ejector comprising a pumping chamber, a membrane defining a top wall of the pumping chamber, and an actuator configured to eject fluid from the pumping chamber and disposed directly on the membrane; comprising; the step of forming at least one compliant structure within the nozzle layer includes forming at least one dummy nozzle in the nozzle layer; each dummy nozzle defines a first opening on an inner surface of the nozzle layer and a second opening on an outer surface of the nozzle layer; the step of attaching the nozzle layer to a substrate comprising a plurality of fluid ejectors includes defining a supply channel in fluid connection with each pumping chamber; wherein the plurality of nozzles are provided along a first line and the supply channel is laterally offset from the first line.

[0118] Embodiment 9 The method according to embodiment 8, wherein each actuator comprises a piezoelectric layer disposed on the membrane.

[0119] Embodiment 10 The method according to embodiment 8, wherein the step of forming at least one compliant structure within the nozzle layer includes forming a plurality of recesses within the nozzle layer and disposing a membrane across the recesses.

[0120] Embodiment 11 The method according to embodiment 10, wherein the step of disposing a membrane across the recesses includes depositing a membrane layer across an upper surface of the nozzle layer and removing a portion of the membrane layer across each nozzle.

[0121] Embodiment 12 The step of forming a plurality of nozzles includes the step of forming the plurality of nozzles in a first layer, and the step of forming at least one compliant structure includes the step of forming the at least one compliant structure in a second layer and the step of attaching the first layer to the second layer, the method according to Embodiment 8.

[0122] Embodiment 13 The step of forming at least one compliant structure in the nozzle layer includes the step of forming the at least one compliant structure in a first layer and the step of attaching the first layer to a second layer having the plurality of nozzles formed therein, the first layer and the second layer both forming the nozzle layer, the method according to Embodiment 8.

[0123] Embodiment 14 The fluid pressure of the supply channel is not high enough to cause fluid to be discharged from the at least one dummy nozzle, the fluid discharge device according to Embodiment 1.

[0124] Embodiment 15 Each fluid ejector has an inlet passage that fluidly connects the supply channel and the pumping chamber of the fluid ejector, the fluid discharge device according to Embodiment 1.

[0125] Embodiment 16 A method of operating a fluid ejector, The step of operating a fluid ejector in a fluid discharge device having a plurality of fluid ejectors, the operation of the fluid ejector causing a change in fluid pressure in a supply channel fluidly connected to the fluid ejector, each fluid ejector comprising a pumping chamber, a membrane defining a top wall of the pumping chamber, an actuator configured to discharge fluid from the pumping chamber and disposed directly on the membrane, and a nozzle, the step of Deflecting a fluid meniscus into a dummy nozzle formed in the feed channel by the change in the fluid pressure; comprising; A method, wherein the nozzles of the plurality of fluid ejectors are provided along a first line, and the feed channel is laterally offset from the first line.

[0126] Embodiment 17 The method according to Embodiment 16, wherein the step of operating any one of the plurality of fluid ejectors does not eject fluid from the dummy nozzle.

[0127] Embodiment 18 The method according to Embodiment 16, wherein each actuator includes a piezoelectric layer disposed on the membrane.

[0128] Embodiment 19 A fluid ejection device, comprising: A plurality of fluid ejectors, each fluid ejector comprising: A pressure feed chamber; An actuator configured to eject fluid from the pressure feed chamber; A nozzle; A fluid ejector comprising; A feed channel fluidly connected to each pressure feed chamber; At least one compliant structure formed in a surface of the feed channel, the at least one compliant structure being more compliant than the surface of the feed channel; Comprising; The at least one compliant structure comprises: A recess formed under the surface of the feed channel; A membrane disposed between the recess and the feed channel; Comprising; The membrane is configured to seal the recess from the feed channel; The recess is configured to be vented to the outside atmosphere via a fluid connection between the recess and an opening in the bottom surface of the substrate. Fluid ejection device.

[0129] Embodiment 20 The fluid ejection device according to Embodiment 19, wherein each fluid ejector includes a nozzle formed in a nozzle layer.

[0130] Embodiment 21 The fluid ejection device according to Embodiment 20, wherein the recess is formed in the nozzle layer.

[0131] Embodiment 22 The fluid ejection device according to Embodiment 20, wherein the nozzle layer is made of silicon and the film is made of silicon.

[0132] Embodiment 23 The fluid ejection device according to Embodiment 19, wherein each fluid ejector includes an actuator and a nozzle, and the operation of the actuator is configured to eject liquid from the corresponding nozzle.

[0133] Embodiment 24 The fluid ejection device according to Embodiment 23, wherein the operation of the actuator changes the fluid pressure in the supply channel, and the at least one compliant structure is configured to at least partially attenuate the change in the fluid pressure in the supply channel.

[0134] Embodiment 25 The fluid ejection device according to Embodiment 19, wherein the recess is a plurality of recesses.

[0135] Embodiment 26 A fluid ejection device, A plurality of fluid ejectors, each fluid ejector comprising: A pumping chamber, An actuator configured to eject fluid from the pumping chamber, A nozzle, And a fluid ejector comprising the same. A feed channel fluidly connected to each pressure chamber, and At least one compliant structure formed within the surface of the feed channel, the at least one compliant structure being more compliant than the surface of the feed channel, and Comprising The at least one compliant structure A recess formed below the surface of the feed channel, and A membrane disposed between the recess and the feed channel, and Comprising The membrane is configured to seal the recess from the feed channel, The recess is configured to be vented to the external atmosphere via a fluid connection between the recess and an opening in the bottom surface of the substrate. Fluid ejection device.

[0136] Embodiment 27 The fluid ejection device according to Embodiment 26, wherein each fluid ejector includes a nozzle formed in a nozzle layer.

[0137] Embodiment 28 The fluid ejection device according to Embodiment 27, wherein the recess is formed in the nozzle layer.

[0138] Embodiment 29 The fluid ejection device according to Embodiment 27, wherein the nozzle layer is silicon and the membrane is silicon.

[0139] Embodiment 30 The fluid ejection device according to Embodiment 26, wherein each fluid ejector includes an actuator and a nozzle, and the operation of the actuator is configured to eject liquid from the corresponding nozzle.

[0140] Embodiment 31 The fluid ejection device according to Embodiment 30, wherein the operation of the actuator changes the fluid pressure in the supply channel, and the at least one compliant structure is configured to at least partially attenuate the change in the fluid pressure in the supply channel.

[0141] Embodiment 32 The fluid ejection device according to Embodiment 26, wherein the recesses are a plurality of recesses.

Explanation of Reference Numerals

[0142] 100 Print head 110 Substrate 410 Casing 420 Upper interposer 422 Fluid supply inlet 428 Fluid return outlet 430 Lower interposer 432 Fluid supply chamber 436 Fluid return chamber 440 Lower divider 474 Flow path 530 Upper divider

Claims

1. 1. A method of dispensing a fluid, comprising: flowing a fluid along a feed channel and into each of a plurality of pumping chambers, an actuator disposed adjacent each of the pumping chambers; activating one or more of the actuators to eject fluid from a corresponding one of the pumping chambers through a corresponding nozzle fluidly connected to the pumping chamber; actuating the one or more actuators causes fluid to flow from the corresponding pumping chamber through a respective descender to the corresponding nozzle; actuating each actuator to cause a deflection of a meniscus of fluid within a dummy nozzle defining an opening in a wall of the feed channel; the nozzles being disposed along a line and the feed channel being laterally offset from the line.

2. The method of claim 1 , wherein the dummy nozzle and the nozzle are defined in a substrate, an inner surface of the substrate forming the walls of the feed channel.

3. The method of claim 2 , wherein the dummy nozzle defines a first opening in the wall of the feed channel and a second opening in an exterior surface of the substrate, the first opening being larger than the second opening.

4. 2. The method of claim 1, wherein actuating each actuator causes a deflection of the meniscus in the second opening of the dummy nozzle, the meniscus being a convex meniscus.

5. The method of claim 1 , wherein deflection of the meniscus at least partially damps changes in fluid pressure in the feed channel caused by actuation of the one or more actuators.

6. The method of claim 1 , wherein no fluid is ejected from the dummy nozzle in response to deflection of the meniscus in the dummy nozzle.

7. 2. The method of claim 1, wherein actuating the one or more actuators causes a first portion of the fluid to be ejected from each nozzle and a second portion of the fluid to flow through a respective outlet passage into a common second feed channel.

8. The method of claim 7 , wherein actuating the one or more actuators causes a deflection of a second meniscus of fluid in a second dummy nozzle defining an opening in a wall of the second feed channel.

9. The method of claim 8 , wherein in response to deflection of the second meniscus in the second dummy nozzle, no fluid is ejected from the second dummy nozzle.

10. 1. A method of dispensing a fluid, comprising: flowing a fluid along a feed channel and into each of a plurality of pumping chambers, an actuator disposed adjacent each of the pumping chambers; activating one or more of the actuators to eject fluid from a corresponding one of the pumping chambers through a corresponding nozzle fluidly connected to the pumping chamber; actuating each actuator to cause a deflection of a meniscus of fluid within a dummy nozzle defining an opening in a wall of the feed channel; the dummy nozzle and the nozzle are defined in a substrate, an inner surface of the substrate forming the walls of the feed channel; the dummy nozzle defines a first opening in the wall of the feed channel and a second opening in an exterior surface of the substrate, the first opening being larger than the second opening; the nozzles being disposed along a line and the feed channel being laterally offset from the line.

Images