An arrayed electrofluid nozzle with inter-field electromagnetic shielding

Abstract

The present invention belongs to the field of inkjet printing, and specifically relates to an arrayed electrofluidic nozzle with inter-field electromagnetic shielding, comprising: an ink cartridge, a microfluidic module, and an integrated nozzle module connected in sequence; the integrated nozzle module comprises a plurality of nozzles and a groundable shielding electrode disposed between each two adjacent nozzles, each nozzle comprising an induction channel and high and low voltage electrodes disposed axially above and below the induction channel; the high and low voltage electrodes on each nozzle excite an induced electric field within the corresponding induction channel, prompting the occurrence of ejection behavior, and the shielding electrodes adjacent to the nozzle, when grounded, suppress electric field crosstalk between the nozzle and other nozzles; the height of each shielding electrode and the spacing between it and its adjacent nozzles ensure that the electric field generated by the high voltage electrode of one nozzle does not affect the ink and ejected ink droplets in the nozzle on the other side, and the low voltage electrode is grounded. The present invention effectively reduces electric field crosstalk between electrofluidic nozzle holes, improving the integration density and production efficiency of the arrayed nozzle.

Description

Technical Field

[0001] The present invention belongs to the field of inkjet printing, and more specifically, relates to an arrayed electrofluid nozzle with inter-field electromagnetic shielding. Background Art

[0002] Electrohydrodynamic printing technology uses an electric field to induce the ejection of functional ink from a nozzle onto a substrate, forming a patterned functional structure. Unlike traditional inkjet printing, which "pushes" ink droplets from the nozzle, electrohydrodynamic printing uses a "pull" method, utilizing an electric field to pull the ink from the nozzle. This technology offers advantages such as high resolution (<0.2μm), a wide range of ink viscosities (1 to 10,000 cps), and customizable high-precision patterning. This has led to widespread application in flexible electronics manufacturing and even biomanufacturing.

[0003] Due to the current limitations of E-fluid printhead frequency and integration, E-fluid printing technology is still concentrated in the laboratory. To bring E-fluid printing technology to the production workshop, arrayed E-fluid printheads have emerged. However, the current arrayed E-fluid printheads have a serious problem of electric field crosstalk, which requires increasing the nozzle spacing to reduce the electric field crosstalk. However, this greatly limits the integration density of the arrayed printheads and reduces production efficiency.

[0004] Chinese patent application CN113478973A proposes a control method for arrayed electrofluidic printheads to suppress jet tilt. However, this method can only suppress jet tilt when the nozzles are spaced one nozzle apart, does not significantly improve the integration density of the arrayed printhead, and has limited production efficiency. Chinese patent application CN112644178A proposes an in-line electrofluidic printhead that uses auxiliary nozzles to suppress jet interference. However, this printhead must limit the outermost nozzles to stop printing, which reduces printing efficiency. It also does not suppress the electric field crosstalk between the middle nozzles, which exacerbates the crosstalk during independent controllable printing. Summary of the Invention

[0005] In response to the defects of the existing technology and the need for improvement, the present invention provides an arrayed electrofluid nozzle with inter-field electromagnetic shielding, which aims to effectively reduce the electric field crosstalk between the arrayed electrofluid nozzle holes to improve the integration density and production efficiency of the arrayed nozzle.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided an arrayed electrofluidic showerhead with inter-field electromagnetic shielding, comprising: an ink cartridge, a micro-channel module and an integrated nozzle module connected in sequence;

[0007] The integrated nozzle module includes a plurality of nozzles and a groundable shielding electrode disposed between each two adjacent nozzles, each nozzle including: an ink flow channel and an induction channel coaxially disposed in sequence, and a high-voltage electrode and a low-voltage electrode disposed at the upper and lower portions of the induction channel in the axial direction thereof;

[0008] When the ink in the ink cartridge flows through the microfluidic module and reaches the induction channel on each nozzle, the high-voltage electrode and the low-voltage electrode on each nozzle will excite the induced electric field in the corresponding induction channel, prompting the occurrence of ejection behavior in the induction channel. After the adjacent shielding electrode of the nozzle is grounded, it can suppress the electric field crosstalk between the nozzle and other nozzles; wherein, the low-voltage electrode is grounded, and the height of each shielding electrode and the distance between it and the adjacent nozzle meet the following requirements: the electric field generated by the high-voltage electrode of the nozzle on one side will not act on the ink in the induction channel of the nozzle on the other side and the ejected ink droplets.

[0009] Furthermore, the shielding electrode is provided in the following manner:

[0010] A cylindrical cavity having a relatively large radius and being coaxial with the ink flow channel and the induction channel on the nozzle is provided on each nozzle;

[0011] An electrode material is provided on the inner wall of the cylindrical cavity to form the shielding electrode.

[0012] Furthermore, a thin film conductor and a grounding pin row electrically connected to each shielding electrode are provided on the ink ejecting side of the integrated nozzle module, and the grounding pin row realizes grounding control of each shielding electrode through the thin film conductor.

[0013] Furthermore, the minimum height of the shielding electrode is:

[0014]

[0015] Where h 屏蔽 represents the minimum height of the shielding electrode, Δx represents the distance between the shielding electrode and the symmetry axis of its corresponding nozzle, D represents the distance between two adjacent nozzles, d represents the inner diameter of the ink flow channel at the maximum inner diameter, L represents the thickness of the integrated nozzle module in the direction of the symmetry axis of the ink flow channel, L 诱 represents the induced channel length;

[0016] At the same time, the distance between the shielding electrode and the symmetry axis of the adjacent nozzle satisfies:

[0017]

[0018] Where H 打印 Indicates the distance between the bottom surface of the integrated nozzle module and the substrate.

[0019] Furthermore, the low-voltage electrode is electrically connected to its adjacent shielding electrode.

[0020] Furthermore, the microchannel module is provided with a microfluidic groove on one side connected to the ink cartridge, and is provided with a control electrode and a plurality of boss electrodes electrically connected thereto on one side connected to the integrated nozzle module;

[0021] The groove shape of the microfluidic channel is a tree-like structure, and the cross-sectional area of ​​each tree-like branch gradually decreases from the two ends of the microfluidic module to the center, and the flow channel in each branch is arc-shaped to improve the uniformity of the diversion. In addition, there is a through hole in the center of the thinnest branches, and the symmetry axis of the through hole coincides with the symmetry axis of the corresponding boss electrode and passes through the entire microfluidic module; the control electrode is used to supply power to the corresponding high-voltage electrodes in the integrated nozzle module through each boss electrode.

[0022] Furthermore, each ink flow channel in the integrated nozzle module includes a nozzle flow inlet and a nozzle flow channel that are coaxially connected in sequence, the inner diameter of the nozzle flow inlet is larger than the inner diameter of the nozzle flow channel, each boss electrode is coaxially interference fit with the corresponding nozzle flow inlet, and a seal is provided between the two.

[0023] Furthermore, the control electrode is composed of a number of parallel linear electrodes, the same number as the boss electrodes, and the microchannel module is also provided with a high-voltage pin array, which is connected to each electrode in the control electrode in a one-to-one correspondence.

[0024] Furthermore, all edges inside the ink storage cavity in the ink cartridge are transitioned through rounded corners.

[0025] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0026] (1) In the present invention, a groundable shielding electrode is provided between each two adjacent nozzles in the integrated nozzle module of the nozzle, and an induction channel is also provided downstream of the ink flow path of each nozzle, and a high-voltage electrode and a low-voltage electrode are also provided at the upper and lower parts of the induction channel in the axial direction, so that the high-voltage electrode and the low-voltage electrode on each nozzle can excite an induced electric field in the corresponding induction channel, thereby promoting the occurrence of ejection behavior in the induction channel. At this time, the adjacent shielding electrode of the nozzle can suppress the electric field crosstalk of the nozzle on the ejection behavior of other nozzles after being grounded; wherein the height of each shielding electrode and the distance between it and the adjacent nozzles meet the following requirements: the electric field generated by the high-voltage electrode of the nozzle on one side will not act on the ink and the ejected ink droplets in the induction channel of the nozzle on the other side, and the low-voltage electrode is grounded. The present invention introduces a high-voltage electrode and a low-voltage electrode, with the low-voltage electrode grounded, to confine most of the electric field to the area above the low-voltage electrode. The shielding electrode then further confines the electric field above the low-voltage electrode to the area between the shielding electrode and the high-voltage electrode. Together, the low-voltage and shielding electrodes form a Faraday cage-like encapsulating structure, thereby confining the electric field to the area between the low-voltage and shielding electrodes. This effectively achieves electromagnetic shielding between the fields, maintaining low electric field crosstalk between nozzles even when nozzle spacing is close and nozzle density is high. Therefore, the present invention can achieve the beneficial effects of increasing nozzle density and reducing electric field crosstalk between nozzles.

[0027] (2) The present invention proposes design criteria for the length of the shielding electrode and the distance between the shielding electrode and adjacent nozzles, thereby suppressing the electric field crosstalk between nozzles and ensuring effective shielding.

[0028] (3) The present invention proposes that the low-voltage electrode is a ground electrode, which is electrically connected to its adjacent shielding electrode, and can realize the integrated production of the low-voltage electrode and the shielding electrode.

[0029] (4) The microfluidic channel in the microfluidic module proposed in the present invention has a tree-like structure. The cross-sectional area of ​​each tree-like branch gradually decreases from the two ends of the microfluidic module to the center, and an arc structure is set at the diversion position, which improves the stability of the ink flow rate in the flow channel and the uniformity of the ink diversion.

[0030] (5) The control electrode proposed in the present invention is composed of a number of parallel linear electrodes, the same number as the boss electrodes. The microfluidic module is also provided with a high-voltage pin array, which is connected to each electrode in the control electrode one by one, so as to realize integrated management. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of an arrayed electrofluid showerhead with inter-field electromagnetic shielding provided by an embodiment of the present invention;

[0032] Figure 2An exploded view of an arrayed electrofluid showerhead with inter-field electromagnetic shielding provided by an embodiment of the present invention;

[0033] Figure 3 A three-dimensional view of the flow inlet side of the integrated nozzle module provided by an embodiment of the present invention;

[0034] Figure 4 An exploded view of the induction channel side of the integrated nozzle module provided by an embodiment of the present invention;

[0035] Figure 5 A cross-sectional view of the assembly of a micro-channel module and an integrated nozzle module provided in an embodiment of the present invention;

[0036] Figure 6 A partial enlarged view of a single nozzle in a cross-sectional view of an assembly of an arrayed electrofluidic nozzle micro-channel module and an integrated nozzle module with inter-field electromagnetic shielding provided by an embodiment of the present invention;

[0037] Figure 7 A side plan view of a microfluidic module according to an embodiment of the present invention;

[0038] Figure 8 An exploded view of the electrode side of a microfluidic module provided in an embodiment of the present invention;

[0039] Figure 9 A cross-sectional view of the ink inlet and outlet of an ink cartridge provided by an embodiment of the present invention;

[0040] Figure 10 A cross-sectional view of the ink cartridge fixing countersunk hole provided by an embodiment of the present invention;

[0041] Figure 11 This is a diagram of the overall logical structure of the arrayed electrofluid showerhead with inter-field electromagnetic shielding provided by an embodiment of the present invention when working in combination with supporting devices.

[0042] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0043] 1 is an ink cartridge; 2 is a microfluidic module; 3 is an integrated nozzle module; 11 is an ink inlet; 12 is an ink outlet; 13 is a microfluidic inlet; 14 is a microfluidic outlet; 15 is a fixed countersunk hole; 16 is a fixed side plate; 17 is an ink storage cavity; 21 is a microfluidic channel; 22 is a boss electrode; 23 is a control electrode; 24 is a high-voltage pin array; 25 is an insulating protective layer; 31 is an ink flow channel; 32 is an induction channel; 33 is a low-voltage electrode; 34 is a shielding cavity; 35 is a high-voltage electrode; 36 is a shielding electrode; 37 is a grounding pin; 38 is a super-hydrophobic protective layer; 39 is a thin film conductor; 311 is a nozzle flow inlet; 312 is a nozzle flow channel. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0045] Example 1

[0046] An arrayed electrofluid nozzle with electromagnetic shielding between fields, such as Figure 1 and Figure 2 As shown, it comprises: an ink cartridge 1, a micro-channel module 2 and an integrated nozzle module 3 which are connected in sequence;

[0047] The integrated nozzle module includes a plurality of nozzles and a groundable shielding electrode 36 disposed between each two adjacent nozzles. Each nozzle includes: an ink flow channel 31 and an induction channel 32 disposed coaxially in sequence, and a high-voltage electrode 35 and a low-voltage electrode 33 disposed at the upper and lower portions of the induction channel in the axial direction.

[0048] The ink in the ink cartridge flows through the microfluidic module to reach the induction channel on each nozzle. The high-voltage electrode and low-voltage electrode on each nozzle will excite the induced electric field in the corresponding induction channel, prompting the occurrence of ejection behavior in the induction channel. After the adjacent shielding electrode of the nozzle is grounded, it can suppress the electric field crosstalk between the nozzle and other nozzles; wherein, the height of each shielding electrode and the distance between it and the adjacent nozzle meet the following requirements: the electric field generated by the high-voltage electrode of the nozzle on one side of the shielding electrode will not act on the ink in the induction channel of the nozzle on the other side and the ejected ink droplets.

[0049] The high voltage electrode and the low voltage electrode are deposited from a conductive material, and the low voltage electrode is grounded. Figure 3 、 Figure 4 and Figure 5 As shown, the integrated nozzle module 3 is composed of several integrated single nozzles, each of which has the same structure. The ink in the ink cartridge flows through the micro-channel module to the induction channel 32 on each nozzle. In the induction channel 32, the ink forms a cone jet or ink droplets under the action of the induction electric field, thereby realizing the electro-hydrodynamic printing of functional ink droplets. 诱 For the induced channel 32, the maximum value of the induced electric field intensity on the symmetry axis can be approximately written as Based on this formula, combined with the relationship between electric field intensity, ink drop volume and frequency and the expected control voltage value, the length L of the induction channel 32 can be designed. 诱 , where r0 is the radius of the cylindrical surface of the induction channel 32, V 控This is the control voltage applied to the high voltage electrode. To avoid electrical breakdown, the voltage value should not be too large.

[0050] In addition, the shielding electrode plays a role in reducing the electric field crosstalk between the array nozzles and improving the density of the array nozzles. According to the uniqueness theorem of the electrostatic field boundary value problem: Where ε0 is the dielectric constant of vacuum, S k is the surface of conductor k, n represents the normal direction, and U is equivalent to the constant potential distribution when all conductors are uncharged. The closed grounded conductor shell can shield the mutual influence of the electric fields inside and outside the shell, thereby enabling the electrostatic shielding effect to be achieved. The height of each shielding electrode and the distance between it and the adjacent nozzles satisfy the following requirements: the electric field generated by the high-voltage electrode of the nozzle on one side of the shielding electrode will not act on the ink in the induction channel of the nozzle on the other side and the ejected ink droplets, so as to meet the shielding of the high-voltage electrode by the shielding electrode. It should be noted that although Figure 1 Three shield electrodes are shown between two adjacent nozzles, but this is for schematic purposes only. Multiple or just one shield electrode is possible. If only one shield electrode exists and its height and spacing from adjacent nozzles meet the aforementioned requirements, a single shield electrode can effectively suppress electric field crosstalk between different nozzles, thereby increasing printhead integration density and reducing electric field crosstalk between nozzles. Furthermore, the shield electrodes between each nozzle are preferably symmetrical relative to the nozzle axis to ensure spatial electric field symmetry and reduce electric field crosstalk.

[0051] Therefore, this embodiment achieves electrostatic shielding by introducing a shielding electrode, isolating the mutual influence between a single nozzle and other nozzles in the array, effectively reducing the electric field crosstalk between the arrayed electrofluid nozzles, and significantly improving the integration density of the arrayed electrofluid nozzles, thereby solving the technical problems of severe electric field crosstalk and low integration density of the arrayed electrofluid nozzles.

[0052] The surface of the induction channel 32 and the bottom surface of the integrated nozzle module 3 may include a super hydrophobic protective layer 38 to prevent the ink from infiltrating and diffusing to the bottom surface of the integrated nozzle module 3, affecting the printing effect. At the same time, the hydrophobic protective layer should also have corrosion resistance and insulation properties to prevent leakage and protect the electrode from oxidation.

[0053] In this embodiment, a high-voltage electrode and a low-voltage electrode are introduced, and the low-voltage electrode is grounded, so that most of the electric field is confined above the low-voltage electrode. Then, by introducing a shielding electrode, the electric field above the low-voltage electrode is further confined between the shielding electrode and the high-voltage electrode. The low-voltage electrode and the shielding electrode together form an enclosing structure similar to a Faraday cage, thereby achieving the purpose of confining the electric field between the low-voltage electrode and the shielding electrode, and effectively achieving the effect of electromagnetic shielding between fields.

[0054] Any shielding electrode structure that can meet the above requirements for shielding electrode height and the spacing between adjacent nozzles can achieve the effects of the present invention, among which the preferred embodiments are as follows: Figure 5 As shown, the shielding electrode can be obtained by setting in the following manner:

[0055] Each nozzle is provided with a cylindrical cavity coaxial with the ink flow channel and induction channel, and having a relatively large radius. Electrode material is applied to the inner wall of the cylindrical cavity to form a shielding electrode. The cylindrical cavity is referred to as the shielding cavity 34. The inner diameter of the shielding cavity 34 must be larger than the inner diameter of the ink flow channel and the diameter of the cylindrical surface of the induction channel 32. The shielding electrode structurally covers the high-voltage electrode, achieving a better shielding effect.

[0056] Furthermore, as a preferred embodiment, the minimum height of each shielding electrode is:

[0057]

[0058] Where h 屏蔽 represents the minimum height of the shielding electrode, Δx represents the distance between the shielding electrode and the symmetry axis of its corresponding nozzle, D represents the distance between two adjacent nozzles, d represents the inner diameter of the ink flow channel at the maximum inner diameter, L represents the thickness of the integrated nozzle module in the direction of the symmetry axis of the ink flow channel, L 诱 represents the induced channel length; it should be noted that the actual shielding electrode can be higher than the above minimum height of the shielding electrode; at the same time, the spacing between each shielding electrode and the symmetry axis of its adjacent nozzle satisfies:

[0059]

[0060] Where H 打印 Indicates the distance between the bottom surface of the integrated nozzle module and the substrate.

[0061] Meeting both of these shield electrode design criteria simultaneously ensures that the electric field generated by the high-voltage electrode within the nozzle does not directly affect the ink in the induction channel of other nozzles or the resulting flying ink droplets. This also ensures that the electric field generated by the high-voltage electrodes within other nozzles does not affect the ink in the induction channel of this nozzle or the resulting flying ink droplets. Using this design criterion to design the shield electrode maximizes the simplicity of the printhead structure and reduces manufacturing costs while maintaining effective shielding.

[0062] As a preferred embodiment, the ink ejecting side of the integrated nozzle module is provided with a thin film conductor 39 and a grounding pin electrically connected to each shielding electrode, and the grounding pin realizes grounding control of each shielding electrode through the thin film conductor 39.

[0063] As a preferred embodiment, the aforementioned low-voltage electrode is electrically connected to its adjacent shielding electrode, forming a stronger, enveloping structure and achieving enhanced shielding effectiveness. In the induction channel 32, when the ink forms a cone jet or droplets under the influence of the induced electric field, thereby achieving electrohydrodynamic printing of functional ink droplets, the shielding electrode, connected to the grounded low-voltage electrode, also serves to reduce electric field crosstalk between the array nozzles, thereby increasing the density of the array nozzles. This design facilitates the integrated manufacture of the low-voltage and shielding electrodes.

[0064] As a preferred embodiment, Figure 7 and Figure 8 As shown, the microfluidic module 2 is made of insulating material injection molding or 3D printing, and its overall shape is similar to a rectangular parallelepiped. The side connected to the ink cartridge is provided with a microfluidic groove 21, and the side connected to the integrated nozzle module is provided with a control electrode and a plurality of boss electrodes 22 electrically connected thereto; that is, the microfluidic groove and the boss electrode are respectively located on two opposite surfaces of the microfluidic module, and the control electrode 23 is located on the bottom surface of the microfluidic module 2, that is, the surface where the boss electrode 22 is located.

[0065] The microfluidic channel has a tree-like structure, and the cross-sectional area of ​​each tree-like branch gradually decreases from the two ends of the microfluidic module to the center, and the flow channel in each branch is arc-shaped to improve the uniformity of the diversion. In addition, there is a through hole in the center of the thinnest branches, and the symmetry axis of the through hole coincides with the symmetry axis of the corresponding boss electrode and passes through the entire microfluidic module; the control electrode is deposited by a conductor material, and a layer of conductor film material is deposited on the outer cylindrical surface and bottom surface of the boss electrode. The control electrode is used to supply power to the corresponding high-voltage electrodes in the integrated nozzle module through each boss electrode.

[0066] The microchannel 21 of the microchannel module 2 receives ink from the ink cartridge or exhausts air through the microchannel inlet 13 and microchannel outlet 14. After being divided by the microchannel 21, the ink flows out through the central through-hole of the microchannel 21. The control electrode 23 is used to selectively apply a control voltage under the control of an external control unit to achieve the purpose of controlling the independent injection of the nozzles.

[0067] Regarding the design of the microfluidic channel 21, the microfluidic channel 21 of the microfluidic module 2 can be processed into various groove structures such as arc shapes on the insulating substrate using processes such as laser ablation and etching. In the equation, ρ is the ink density, v is the ink velocity, and t is time. To ensure a stable ink velocity in the flow channel, the flow channel cross-sectional area of ​​this structure gradually decreases from the outside to the inside. This means that v1S1 = v2S2, where v1 is the upstream ink velocity in the microchannel 21, S1 is the upstream microchannel groove cross-sectional area, v2 is the downstream ink velocity in the microchannel 21, and S2 is the downstream microchannel groove cross-sectional area. Several of the smallest microchannels 21 in the center have through-holes at their centers. These through-holes extend through the boss electrode 22, which is coaxially nested with the nozzle flow inlet 31.

[0068] As a preferred embodiment, each ink flow channel in the integrated nozzle module includes a nozzle flow inlet and a nozzle flow channel that are coaxially connected in sequence, and each boss electrode is coaxially interference fit with the corresponding nozzle flow inlet, that is, the outer diameter of each boss in the boss electrode 22 is slightly larger than the diameter of each countersunk hole in the nozzle flow inlet 311, which is used to meet the sealing requirements at the nozzle flow inlet 311 and ensure the stability of the flow at the nozzle, and a seal is further provided between the boss electrode and the nozzle flow inlet.

[0069] It should be noted that, in order to ensure sufficient supply of the nozzle flow, the inner diameter of the through hole of the boss electrode 22 must be larger than the inner diameter of the nozzle flow channel 312. The head loss introduced thereby is:

[0070]

[0071] Wherein, A2 is the cross-sectional area of ​​the nozzle flow channel 312, A1 is the cross-sectional area of ​​the through hole of the boss electrode 22, V2 is the velocity of the ink in the nozzle flow channel 312, and g is the acceleration due to gravity.

[0072] In addition, regarding the arrangement of the high voltage electrodes, it can be used as an example, as follows Figure 6 As shown, the high-voltage electrode 35 is disposed on the wall of the nozzle flow inlet 311, the wall of the nozzle flow channel 312, and the wall of the induction channel 32 near the nozzle flow channel 312 and perpendicular to the rotational symmetry axis of the nozzle flow channel 312; the shield electrode 36 is disposed on the wall of the shield cavity 34, and the low-voltage electrode 33 is disposed on the wall of the integrated nozzle module 3 that contacts the induction channel 32 and is perpendicular to the rotational symmetry axis of the induction channel 32. The low-voltage electrode 33 is connected to the shield electrode 36. The high-voltage electrode and the boss electrode are tightly fitted to maintain the same potential due to the interference fit between the boss electrode 22 and the nozzle flow inlet 311.

[0073] Further explanation: the integrated nozzle module 3 is made of insulating material except for the electrodes. When the low-voltage electrode is a ground electrode and is electrically connected to its adjacent shielding electrode, the high-voltage electrode 35, the shielding electrode 36, and the low-voltage electrode 33 are made of conductive material deposited on the insulating material. The high-voltage electrode 35 is connected to the control voltage 23 via the thin film electrode on the boss electrode 22 to control whether the nozzle is ejected and the ejection performance and state. The low-voltage electrode 33 and the shielding electrode 36 are grounded to form an induced electric field with the high-voltage electrode to induce electrospraying and effectively reduce the mutual crosstalk between the electric fields of each nozzle, thereby improving the electrospraying accuracy and the integration density of the arrayed nozzle. The low-voltage electrode 33 and the shielding electrode 36 are connected to the thin film wire 39 deposited on the integrated nozzle module 3; the thin film wire 39 is in turn connected to the grounding pin 37; the grounding pin 37 is grounded, thereby grounding the low-voltage electrode 33, the shielding electrode 36, and the thin film wire 39 on the integrated nozzle module 3 at the same time to meet the requirements of electric field shielding and induced ejection. The conductive thin film electrodes including the high voltage electrode 35 , the low voltage electrode 33 and the shielding electrode 36 can be obtained by using processes such as magnetron sputtering, vacuum evaporation or photolithography.

[0074] As an example, the nozzle flow inlet 311 and the induction channel 32 are respectively countersunk holes located on two opposite surfaces of the integrated nozzle module 3. In addition, the nozzle flow channel 312 is equivalent to a through hole connecting the nozzle flow inlet 311 and the induction channel 32.

[0075] As a preferred embodiment, the control electrode 23 is composed of a number of parallel straight electrodes, the same number as the boss electrodes 22, and each electrode extends from a position close to the short side of the microfluidic module 2 with the boss electrode 22 to the vicinity of the boss electrode 22, and maintains the same electric potential as the conductor film material deposited on the outer cylindrical surface of each boss electrode 22 through direct contact with the conductor material; a high-voltage pin array 24 is also provided on the microfluidic module, which is connected to each electrode in the control electrode 23 one by one.

[0076] Specifically, the control electrode 23 is a conductive material deposited on an insulating material. Except for the farthest end of the electrode, which receives the control voltage from the control unit, the rest of the electrode is coated with a corrosion-resistant insulating protective layer 25 to prevent leakage and protect the electrode from oxidation. A thin layer of conductive film is deposited on both the outer cylindrical surface and the bottom annular surface of the boss electrode 22, which transmits the control voltage from the control electrode 23 to the high-voltage electrode 35. A high-voltage pin array 24 is connected to the control electrode 23 and corresponds to it one-to-one. This high-voltage pin array 24 is used to input the external control voltage to the nozzle control electrode 23, thereby controlling the nozzle spray.

[0077] like Figure 9 and Figure 10As shown, the ink cartridge 1 can be manufactured using insulating material injection molding or 3D printing, and includes a fixed countersunk hole 15, a fixed side plate 16, an ink storage cavity 17, an ink inlet 11, an ink outlet 12, a microchannel inlet 13, and a microchannel outlet 14; the fixed side plates 16 are located on both sides of the ink cartridge 1, and the fixed countersunk hole 15 is arranged on the fixed side plates 16; the ink inlet 11 and the ink outlet 12 are arranged on a side of the ink cartridge 1 where the fixed side plate 16 is not provided, and their rotational symmetry axes are parallel to the rotational symmetry axes of the fixed countersunk hole 15; the microchannel inlet 13 and the microchannel outlet 14 are arranged on the opposite side of the surface where the ink inlet 11 and the ink outlet 12 are located; the ink storage cavity 17 is a cavity area located inside the body of the ink cartridge 1; the ink inlet 11, the ink outlet 12, the microchannel inlet 13 and the microchannel outlet 14 are connected through the ink storage cavity 17.

[0078] Under the control of the ink flow controller, ink flows from the ink inlet 11 through the external ink supply tube into the ink storage cavity 17. During the ink supply process, the ink gradually fills the ink storage cavity 17, and air is discharged from the ink outlet 12. To ensure a constant flow rate through the nozzle, the ink outlet 12 is closed after all the air is exhausted. The ink flow rate in the nozzle is now completely controlled by the ink flow controller. Two holes are opened in the center of the bottom of the ink cartridge 1: the microchannel inlet 13 and the microchannel outlet 14. During the air exhaust process, the microchannel inlet 13 is used to allow ink to flow into the microchannel 21, and the microchannel outlet 14 is used to exhaust air. During the printing process, both the microchannel inlet 13 and the microchannel outlet 14 are used to allow ink to flow into the microchannel 21. Four fixed countersunk holes 15 are provided on the fixed side panels 16 on either side of the top of the ink cartridge 1 for securing the ink cartridge to the printing platform. To facilitate ink replacement and cleaning of the ink cartridge cavity 17, the ink inlet 11, ink outlet 12, microchannel inlet 13, microchannel outlet 14, and ink cartridge cavity 17 are all coated with a superhydrophobic coating. Furthermore, as a preferred embodiment, all edges within the ink storage cavity 17 of the ink cartridge 1 are rounded to ensure that the ink in the cartridge 1 flows fully into the microchannel module.

[0079] It should be noted that the main body of the ink cartridge 1 and the microfluidic module 2 is made of an insulating material, and the side of the microfluidic module 2 with the control electrode 23 is also coated with an insulating protective layer 25, which is corrosion-resistant. In addition, the inner wall surfaces of the ink cartridge 1, the microfluidic module 2, and the integrated nozzle module 3 that are in contact with the ink are coated with a super-hydrophobic coating to facilitate ink replacement and nozzle cleaning. In particular, the wall surfaces of the induction channel 32 and the integrated nozzle module 3 that are in contact with the induction channel 32 and the shielding cavity 34 and perpendicular to the rotational symmetry axis of the induction channel 32 are coated with a super-hydrophobic coating.

[0080] In order to realize the above nozzle, the following example is given:

[0081] The ink cartridge 1 is made of inorganic glass through an injection molding process. The inner diameters of the ink inlet 11 and outlet 12 are 2000 μm, while the inner diameters of the microchannel inlet 13 and outlet 14 are 1200 μm. The ink inlet 11 and microchannel inlet 13 are not coaxial, and the same applies to the other set. The large diameter of the countersunk hole is 1500 μm, and the small diameter is 1000 μm.

[0082] The microfluidic module 2 is made of inorganic glass through an injection molding process. The microfluidic channel 21 uses a laser ablation process to obtain a tree-like symmetrical bifurcated groove ink path structure. The microfluidic channel 21 has a depth of 100 μm and widths from small to large are 150 μm, 300 μm, 600 μm, and 1200 μm, respectively. In the center of each microfluidic channel 21 with the smallest width, there is a tiny hole with a diameter of 100 μm. This hole is the through hole of the boss electrode 22, which is obtained by a laser ablation process. The outer diameter of the bottom boss electrode 22 of the microfluidic module 2 is 150 μm and is obtained through an integrated injection molding process. A layer of metal film conductive layer is attached to its surface using a magnetron sputtering process. The adhesion layer of the metal film conductive layer is titanium with a thickness of 0.1 μm, and the conductive layer is gold with a thickness of 0.05 μm. The control electrode 23 is prepared in the same way. The diameter of the surrounding boss is 200 μm, the width of the straight segment is 50 μm, and the exposed electrode is a square structure with a side length of 200 μm. After preparation, the control electrode 23 is sealed with epoxy resin glue except for the exposed square structure. That is, the insulating protective layer 25 uses epoxy resin material.

[0083] The integrated nozzle module 3 is prepared using inorganic glass through an injection molding process, and eight nozzles are obtained by a laser ablation process. Each nozzle is integrated with a coaxially arranged nozzle flow inlet 311, a nozzle flow channel 312, an induction channel 32, a shielding cavity 34, a high-voltage electrode 35, a low-voltage electrode 33 and a shielding electrode 36. The inner diameter of the nozzle flow inlet 311 is 150μm and the length is 100μm. The inner diameter of the nozzle flow channel 312 is 80μm. The inner diameter of the induction channel 32 is 112μm and the length is 200μm. The smaller diameter of the shielding cavity 34 is 240μm, the larger diameter of the shielding cavity 34 is 280μm and the length is 900μm. The overall height of the integrated nozzle module 3 is 1000μm. The high-voltage electrode 35, the low-voltage electrode 33 and the shielding electrode 36 are prepared by a vacuum evaporation process. The material and thickness of the adhesion layer and the conductive layer are the same as those of the control electrode 23. The high-voltage electrode 35 is arranged at the nozzle flow inlet 311, the wall of the nozzle flow channel 312 and the wall in the induction channel 32 close to the nozzle flow channel 312 and perpendicular to the rotational symmetry axis of the nozzle flow channel 312; the low-voltage electrode 33 and the shielding electrode 36 are arranged on the wall of the shielding cavity 34 and the wall in the integrated nozzle module 3 that is in contact with the induction channel 32 and perpendicular to the rotational symmetry axis of the induction channel 32; the low-voltage electrode 33 and the shielding electrode 36 are connected to the thin film wire 39 deposited on the integrated nozzle module 3, and are grounded at the same time.

[0084] The ink inlet 11, ink outlet 12, microchannel inlet 13, microchannel outlet 14, ink cartridge cavity 17, microfluidic channel 21, induction channel 32, and the bottom surface of the integrated nozzle module 3 require a Teflon hydrophobic layer formed using a vapor deposition process to prevent ink diffusion. This super-hydrophobic protective layer 38 uses Teflon material, achieving both hydrophobicity and insulation protection. Both the high-voltage pin array 24 and the ground pin array 37 are stainless steel needles and require conductive tape to adhere to the exposed locations of the corresponding electrodes.

[0085] The ink cartridge 1, the microfluidic module 2 and the integrated nozzle module 3 are all tightly bonded with epoxy resin glue. When in use, align the fixed countersunk hole 15 on the ink cartridge 1 with the fixed threaded hole on the printing platform, and use bolts to fix the nozzle as a whole on the printing platform. Use a plastic hose to connect the ink flow controller and the ink inlet 11, and the ink flow controller uses a precision flow pump to maintain the stability of the flow. Before printing, it is necessary to introduce sufficient ink to remove the air in the nozzle. The air in the cavity will be discharged from the induction channel 32 and the ink outlet 12. After the air is completely discharged, the ink outlet 12 needs to be completely closed to ensure that the flow of ink in the nozzle is completely controlled by the ink flow controller.

[0086] In a preferred embodiment of the present invention, after the air removal step is completed, the bottom surface of the integrated nozzle module 3 and the induction channel 32 need to be wiped to ensure dryness. Figure 11 As shown, the control unit is then connected to the control electrode 23 on the bottom surface of the microfluidic module 2 via a wire. For the nozzles that need to be sprayed, the applied voltage is 300V. In other words, the control unit needs to be coded so that the control electrode 23 corresponding to the corresponding nozzle is connected to a 300V voltage. The other nozzles that do not need to spray can be grounded. In this way, independent controllable printing can be achieved. Due to the influence of the grounding of the low-voltage electrode 33 and the shielding electrode 36, the turn-on voltage of the nozzle of the present invention is much lower than that of a typical nozzle, and the degree of electric field crosstalk is also much lower than that of a typical nozzle. The voltage applied to the nozzle can be changed according to the required ink droplet volume and frequency, but it should not be too large to prevent electrical breakdown, nor too small, otherwise the nozzle will not be sprayed.

[0087] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An arrayed electrofluid showerhead with inter-field electromagnetic shielding, characterized in that: include: An ink cartridge, a microfluidic module, and an integrated nozzle module are sequentially connected; The integrated nozzle module includes a plurality of nozzles and a groundable shielding electrode disposed between each two adjacent nozzles, each nozzle including: an ink flow channel and an induction channel coaxially disposed in sequence, and a high-voltage electrode and a low-voltage electrode disposed at the upper and lower portions of the induction channel in the axial direction thereof; When the ink in the ink cartridge flows through the microfluidic module and reaches the induction channel on each nozzle, the high-voltage electrode and the low-voltage electrode on each nozzle will excite an induced electric field in the corresponding induction channel, prompting the occurrence of ejection behavior in the induction channel. After the adjacent shielding electrode of the nozzle is grounded, it can suppress the electric field crosstalk between the nozzle and other nozzles; wherein, the low-voltage electrode is grounded, and the height of each shielding electrode and the distance between it and the adjacent nozzle meet the following requirements: the electric field generated by the high-voltage electrode of the nozzle on one side will not act on the ink in the induction channel of the nozzle on the other side and the ejected ink droplets; Wherein, the minimum height of the shielding electrode is: Where h 屏蔽 represents the minimum height of the shielding electrode, Δx represents the distance between the shielding electrode and the symmetry axis of its corresponding nozzle, D represents the distance between two adjacent nozzles, d represents the inner diameter of the ink flow channel at the maximum inner diameter, L represents the thickness of the integrated nozzle module in the direction of the symmetry axis of the ink flow channel, L 诱 represents the induced channel length; At the same time, the distance between the shielding electrode and the symmetry axis of the adjacent nozzle satisfies: Where H 打印 Indicates the distance between the bottom surface of the integrated nozzle module and the substrate.

2. The arrayed electrofluid showerhead according to claim 1, wherein: The shielding electrode is provided in the following manner: A cylindrical cavity having a relatively large radius and being coaxial with the ink flow channel and the induction channel on the nozzle is provided on each nozzle; An electrode material is provided on the inner wall of the cylindrical cavity to form the shielding electrode.

3. The arrayed electrofluid showerhead according to claim 1 or 2, characterized in that: The ink-spraying side of the integrated nozzle module is provided with thin film conductors and grounding pins electrically connected to the shielding electrodes. The grounding pins realize grounding control of the shielding electrodes through the thin film conductors.

4. The arrayed electrofluid showerhead according to claim 1, wherein: The low-voltage electrode is electrically connected to its adjacent shielding electrode.

5. The arrayed electrofluid showerhead according to claim 1, characterized in that: The microchannel module is provided with a microfluidic groove on one side connected to the ink cartridge, and a control electrode and a plurality of boss electrodes electrically connected thereto on one side connected to the integrated nozzle module; The groove shape of the microfluidic channel is a tree-like structure, and the cross-sectional area of ​​each tree-like branch gradually decreases from the two ends of the microfluidic module to the center, and the flow channel in each branch is arc-shaped. There is a through hole in the center of the thinnest branches. The through hole passes through the entire microfluidic module and its symmetry axis coincides with the symmetry axis of the corresponding boss electrode; the control electrode is used to supply power to the corresponding high-voltage electrodes in the integrated nozzle module through each boss electrode.

6. The arrayed electrofluid showerhead according to claim 5, characterized in that: Each ink flow channel in the integrated nozzle module includes a nozzle flow inlet and a nozzle flow channel that are coaxially connected in sequence. The inner diameter of the nozzle flow inlet is larger than the inner diameter of the nozzle flow channel. Each boss electrode is coaxially interference fit with the corresponding nozzle flow inlet, and a seal is provided between the two.

7. The arrayed electrofluid showerhead according to claim 5, characterized in that: The control electrode is composed of a number of parallel linear electrodes, the same number as the boss electrodes. The microchannel module is also provided with a high-voltage pin array, which is electrically connected to each electrode in the control electrode in a one-to-one correspondence.

8. The arrayed electrofluid showerhead according to claim 1, wherein: All edges inside the ink storage cavity in the ink cartridge are transitioned through rounded corners.

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