Electrostatic jet printing nozzle with adjustable jet range

Abstract

The invention provides an electrostatic jet printing nozzle with an adjustable spraying range, and relates to the technical field of electrostatic nozzles. A nozzle is arranged at one end of the spray head body, the liquid inlet assembly is arranged on the spray head body, the pneumatic assembly is arranged on the spray head body and controls solution spraying, and the control mechanism is arranged on the spray head body and controls the spraying range. The control mechanism comprises an adjusting ring arranged at the end, away from the nozzle body, of the nozzle in parallel, a distance adjusting assembly arranged on the nozzle body and controlling the adjusting ring to be close to or away from the nozzle at equal intervals, and two profiling electrodes symmetrically arranged on the two sides of the end face of the end, away from the nozzle, of the adjusting ring. A plurality of limiting grooves are concavely formed in the inner wall of the inner ring channel of the adjusting ring in a stepped mode in the direction from the nozzle to the adjusting ring, each limiting groove is of a circular-truncated-cone-shaped structure, and the opening, close to the nozzle, of each limiting groove is smaller than the opening, away from the nozzle, of the limiting groove. The spraying range of the spraying head can be accurately controlled conveniently, and the uniformity of the particle size of fog drops is improved.

Description

Technical Field

[0001] This invention relates to the field of electrostatic printhead technology, specifically to an electrostatic printing printhead with adjustable spray range. Background Technology

[0002] Electrostatic inkjet printing technology, with its advantages of small droplet size, high resolution, and high material utilization, is widely used in microelectronics, flexible electronics, semiconductor lithography, and other fields. As the core component of this technology, the printhead's adjustability of the spray range, atomization uniformity, and adjustment precision directly determine the printing quality. However, existing electrostatic inkjet printheads still face several key challenges in practical applications:

[0003] 1. Existing technologies mostly rely on electric field control (such as changing the electrode spacing or electrode on / off state) or mechanical angle adjustment, which makes it difficult to achieve continuous and precise range adjustment and is prone to interference with the atomization effect; some solutions achieve range variation by changing the nozzle or adjusting the air pressure, but these have drawbacks such as cumbersome operation, discontinuous adjustment, and uneven droplet size.

[0004] 2. Electric field controlled printheads are prone to jet deflection due to electric field distortion, and may even cause ink droplets to accumulate on the electrodes, affecting the continuity of printing; pneumatically assisted atomization printheads have uneven airflow distribution and cannot effectively constrain the shape of the mist, resulting in large dispersion of edge droplets.

[0005] To address the above problems, existing published patents have proposed corresponding technical solutions, but they still have significant shortcomings:

[0006] 1. A multi-ring, segmented, adjustable inner diameter coaxial electro-inkjet printhead and conformal printing method, disclosed in CN115179655B, changes the electric field strength by adjusting the number of rings and segments of the electrode rings to adapt to printing on non-planar substrates. The drawbacks are that it relies on the electric field to control the spraying state, which easily generates electric field crosstalk and has a high risk of jet deviation; the adjustment range is limited, and continuous linear adjustment of the spraying range cannot be achieved.

[0007] 2. The arrayed electrohydrodynamic printhead with independently controllable nozzle ejection and its implementation method disclosed in CN104191819B achieves independent ejection control by setting extraction electrodes. Its drawbacks include the difficulty in electrode assembly, the tendency for ink to slant and accumulate on the electrodes leading to printhead malfunction, and the lack of addressing ejection range adjustment, thus limiting its applicability.

[0008] 3. A pneumatic atomizing electrostatic nozzle and spray system with publication number CN108435450A uses high-speed airflow atomization + metal mesh charging to improve charging effect and deposition efficiency. The drawbacks are that the spray range depends on air pressure adjustment, resulting in low precision and uneven droplet size; it also lacks a dedicated mist stream confinement structure, leading to severe edge droplet diffusion.

[0009] Therefore, developing a nozzle that addresses the limitations and insufficient synergy of existing adjustment methods through the synergistic effect of mechanical structure, pneumatics, and electrostatics is of significant practical importance. Summary of the Invention

[0010] To address the above problems, the present invention provides an electrostatic inkjet printhead with adjustable spray range.

[0011] To achieve the above objectives, the present invention provides the following technical solution: an electrostatic inkjet printhead with adjustable spray range, comprising a printhead body with a nozzle at one end, a liquid inlet assembly disposed on the printhead body, a pneumatic assembly disposed on the printhead body and controlling the liquid spray, and a control mechanism disposed on the printhead body and controlling the spray range. The control mechanism includes an adjustment ring disposed parallel to the nozzle at the end away from the printhead body, an adjustment distance assembly disposed on the printhead body and controlling the adjustment ring to be equidistant from or away from the nozzle, and two contour electrodes symmetrically disposed on both sides of the end face of the adjustment ring at the end away from the nozzle. The inner wall of the inner ring channel of the adjustment ring is provided with a plurality of limiting grooves in a stepped manner from the nozzle toward the adjustment ring. Each limiting groove is a frustum-shaped structure, and the opening of the limiting groove near the nozzle is smaller than the opening away from the nozzle.

[0012] During the spraying process, the liquid inlet assembly controls the solution to enter the nozzle, and the pneumatic assembly applies air pressure to the nozzle body, driving the solution in the nozzle to be sprayed out in the form of a cone-shaped mist. The sprayed cone-shaped mist passes through the inner ring channel, and the discrete droplets at the edge of the mist come into contact with and are blocked by the wall of the limiting groove. Then it passes between two contour electrodes. The contour electrodes are energized to generate an electrostatic field, which further atomizes the cone-shaped mist.

[0013] When adjusting the spray range, the adjusting component controls the adjusting ring to move away from the nozzle. At this time, the contact area between the groove wall of the limiting groove and the edge of the conical mist beam expands, constraining the conical mist beam, limiting the diffusion angle, and reducing the spray range.

[0014] Preferably, the multiple limiting grooves are provided in a stepped manner on the inner wall of the inner ring channel from the nozzle toward the adjusting ring, with a second limiting groove and a first limiting groove. The walls of the first limiting groove and the second limiting groove are evenly provided with guide grooves opened along the generatrix direction. The guide grooves are connected to the pneumatic components through auxiliary parts.

[0015] Preferably, the adjusting component includes a mounting ring sleeved on the nozzle end of the nozzle body, a control ring rotatably mounted on the outer ring of the mounting ring via a positioning member, two control rods symmetrically and vertically mounted on the outer ring of the adjusting ring, a slide rod vertically mounted on the end face of the mounting ring along the parallel axis of the adjusting ring, and an adjusting member mounted on the control ring and controlling the adjusting ring to slide along the length of the slide rod, wherein the slide rod moves through the body of the control rod.

[0016] Preferably, the outer ring surface of the mounting ring has multiple buffer grooves arranged in a circular array, and the positioning element includes multiple positioning balls that are inserted into the opening positions of the buffer grooves through an elastic structure. The inner ring surface of the control ring has multiple positioning holes that correspond to the multiple positioning balls.

[0017] Preferably, the adjusting component includes an adjusting rod vertically disposed on the bottom side of the control rod, and a rotating column rotatably disposed on the bottom end of the adjusting rod near the side of the control ring. An adjusting groove sleeved on the rotating column is provided on the inner ring of the control ring, and the distance between the two ends of the adjusting groove opening along the axial direction of the control ring is the sum of the depths of the first limiting groove and the second limiting groove.

[0018] Preferably, the nozzle body is fixedly provided with a spray ring at the center of one end face of the nozzle, and the side of the spray ring is provided with multiple second air supply channels connected to the pneumatic components, and the nozzle orifice is directly opposite the inner ring of the spray ring.

[0019] Preferably, the inner ring of the injection ring is provided with multiple spiral grooves in a circular array, and the openings of the multiple spiral grooves near the nozzle end are respectively connected to the second gas delivery channel; a spiral plate is provided vertically on the bottom wall of the spiral groove along the length direction of the opening.

[0020] Preferably, the nozzle body has a cavity, and the cavity is provided with a partition column that divides the two ends of the cavity into a first sealing cavity and a second sealing cavity, each containing a nozzle. The partition column has a first air supply channel that passes through the first sealing cavity and the second sealing cavity. The pneumatic component sequentially supplies gas to the inner ring of the spray ring through an air inlet hole, the first air supply channel, the first sealing cavity, and the second air supply channel in the wall of the second sealing cavity. A liquid inlet column connected to the partition column passes through the second sealing cavity. The liquid inlet component controls the solution to sequentially pass through an inlet hole in the liquid inlet column and the first liquid supply channel in the partition column to the nozzle and the spray cavity.

[0021] Preferably, the second air supply channel is connected to the pneumatic assembly via a connector. The connector includes a connecting ring disposed in the first sealing cavity and sleeved on the nozzle, and a plurality of fixed tubes arranged in a circumferential array on one end face of the connecting ring. The plurality of fixed tubes are sealed and inserted into one end opening of the plurality of second air supply channels, and the side of the connecting ring has an opening that communicates with the interior of the plurality of fixed tubes.

[0022] Preferably, the adjusting ring has a collecting cavity that communicates with multiple connecting holes, the nozzle body has a first conveying hole that communicates with the first sealing cavity on the end face of the nozzle, and when the mounting ring is installed on the end face of the nozzle body, the mounting ring has a second conveying hole that communicates with the first conveying hole. The auxiliary component includes a connecting pipe with its two ends respectively installed on the mounting ring and the adjusting ring, and the connecting pipe communicates with the second conveying hole and the collecting cavity.

[0023] The beneficial effects of this invention are:

[0024] 1. The adjusting ring works in conjunction with the stepped frustum-shaped limiting groove to physically block the discrete droplets at the edge of the conical mist beam. Combined with the pitch adjustment component, the adjusting ring is driven to move along the nozzle axis to achieve linear changes in the contact area, thereby precisely controlling the diffusion angle to meet the range requirements of different printing scenarios.

[0025] 2. The limiting groove adopts a frustum-shaped structure with a small opening near the nozzle and a large opening far from the nozzle. Combined with the synergistic effect of the guide groove and pneumatic components, it not only ensures the constraint effect but also avoids atomization failure caused by excessive obstruction, and the adjustment range is wider.

[0026] 3. The spiral groove and spiral plate design of the injection ring enables the gas delivered by the pneumatic components to form a uniform spiral airflow, which initially shapes the conical mist jet ejected from the nozzle; the electrostatic field generated by the contour electrode further refines the atomization, forming a three-level synergistic mechanism of "pneumatic shaping + electrostatic atomization + mechanical constraint", which improves the uniformity of droplet size. Attached Figure Description

[0027] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0028] Figure 1 This is a simplified structural diagram of the electrostatic inkjet printhead with adjustable spray range proposed in this invention.

[0029] Figure 2 for Figure 1 Enlarged structural diagram at point A in the middle.

[0030] Figure 3 This is a schematic diagram of the unfolded structure of the electrostatic inkjet printhead with adjustable spray range according to the present invention.

[0031] Figure 4 This is a schematic diagram of the other side of the electrostatic inkjet printhead with adjustable spray range according to the present invention.

[0032] Figure 5 This is a schematic diagram of the unfolded cross-sectional structure of the electrostatic inkjet printhead with adjustable spray range according to the present invention.

[0033] Figure 6 for Figure 5 Enlarged structural diagram at point B.

[0034] Figure 7 This is a schematic diagram of the unfolded cross-section of the nozzle body of the present invention.

[0035] Figure 8 This is a schematic diagram of the control mechanism structure of the present invention.

[0036] Figure 9 for Figure 8 Enlarged structural diagram at point C.

[0037] Figure 10 This is a schematic diagram of the cross-sectional structure of the auxiliary component of the present invention.

[0038] In the diagram: 1. Nozzle body; 2. Mounting ring; 3. Control ring; 4. Spray ring; 5. Adjusting ring; 6. Contouring electrode; 7. Control rod; 8. Slide rod; 9. Connecting pipe; 10. First limiting groove; 11. Second limiting groove; 12. Inner ring channel; 13. Guide groove; 14. Connecting hole; 15. First conveying hole; 16. Second conveying hole; 17. Liquid inlet hole; 18. Air inlet hole; 19. Nozzle; 20. Spray chamber; 21. Separator column; 22. First liquid delivery channel; 23. First air delivery channel; 24. Liquid inlet column; 25. Connecting ring; 26. Fixing pipe; 27. Second air delivery channel; 28. Spiral groove; 29. ​​Spiral plate; 30. Adjustment groove; 31. Adjustment rod; 32. Buffer groove; 33. Buffer spring; 34. Positioning ball; 35. Positioning hole. Detailed Implementation

[0039] To make the technical means, creative features, achieved objectives, and effects of this invention readily understandable, the invention is further described below with reference to specific embodiments and accompanying drawings. However, the following embodiments are merely preferred embodiments of this invention and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this invention.

[0040] The operation process of existing electrostatic inkjet printheads is usually as follows: the liquid inlet component delivers the printing solution into the cavity of the printhead body, the pneumatic component applies a preset air pressure to the cavity to drive the solution to be ejected from the nozzle, and the ejected droplets are atomized by the electrostatic field generated by the electrodes on the side of the printhead to form a mist, and finally complete the printing operation.

[0041] However, the existing technology has obvious shortcomings: First, the adjustment of the spray range mainly depends on changing the electric field strength of the electrode or replacing nozzles with different orifice diameters. The former is prone to mist beam deviation due to electric field distortion, while the latter is cumbersome to operate and cannot achieve continuous adjustment. Second, the sprayed mist beam lacks an effective regular constraint structure, with many discrete droplets at the edges and poor uniformity of droplet size, which further affects the spray stability.

[0042] To address the core issues of "low adjustment accuracy and poor atomization uniformity" mentioned above, this invention proposes an electrostatic inkjet printhead with an optimized structure and adjustable spray range.

[0043] Example 1: Reference Figures 1-10An adjustable spray range electrostatic inkjet printhead is shown, comprising a printhead body 1 with a nozzle 19 at one end, a liquid inlet assembly disposed on the printhead body 1, a pneumatic assembly disposed on the printhead body 1 and controlling the liquid spray, and a control mechanism disposed on the printhead body 1 and controlling the spray range. The control mechanism includes an adjustment ring 5 disposed parallel to the end of the nozzle 19 away from the printhead body 1, a distance adjustment assembly disposed on the printhead body 1 and controlling the adjustment ring 5 to be equidistant from or away from the nozzle 19, and two contoured electrodes 6 symmetrically disposed on both sides of the end face of the adjustment ring 5 away from the nozzle 19. The inner wall of the inner ring channel 12 of the adjustment ring 5 is provided with a plurality of limiting grooves in a stepped manner from the nozzle 19 toward the adjustment ring 5. Each limiting groove is a frustum-shaped structure, and the opening of the limiting groove near the nozzle 19 is smaller than the opening away from the nozzle 19.

[0044] During the spraying process, the liquid inlet assembly controls the solution to enter the nozzle 19, and the pneumatic assembly applies air pressure to the nozzle body 1, driving the solution in the nozzle 19 to be sprayed out in the form of a cone-shaped mist. The sprayed cone-shaped mist passes through the inner ring channel 12, and the discrete droplets at the edge of the mist form contact with the wall of the limiting groove and are blocked, and then pass between the two contour electrodes 6. The contour electrodes 6 are energized to generate an electrostatic field, which further atomizes the cone-shaped mist.

[0045] When adjusting the spray range, the distance adjustment component controls the adjustment ring 5 to move away from the nozzle 19. At this time, the contact area between the groove wall of the limiting groove and the edge of the conical mist beam expands, constraining the conical mist beam, limiting the diffusion angle, and reducing the spray range.

[0046] In this embodiment, the liquid inlet assembly first controls the solution to enter the nozzle 19 of the printhead body 1. Then, the pneumatic assembly applies air pressure to the printhead body 1, driving the solution in the nozzle 19 to be sprayed out in a conical mist. The sprayed conical mist then passes through the inner ring channel 12 of the adjusting ring 5. The discrete droplets at the edge of the mist come into contact with and are blocked by the stepped concave truncated limiting groove (the opening near the nozzle 19 is smaller than the opening away from the nozzle 19) on the inner wall of the inner ring channel 12 of the adjusting ring 5 from the nozzle 19 toward the adjusting ring 5. Subsequently, the conical mist passes between two symmetrically arranged contour electrodes 6 on both sides of the end face of the adjusting ring 5 away from the nozzle 19. The contour electrodes 6 are energized to generate an electrostatic field to further atomize the conical mist, finally completing the printing operation. When it is necessary to adjust the spray range, the distance adjustment assembly controls the adjusting ring 5 along the axis of the nozzle 19. As the spray pattern moves equidistantly away from the nozzle 19, the contact area between the wall of the limiting groove and the edge of the conical mist beam expands, effectively constraining the conical mist beam to limit the diffusion angle and reduce the spray range. When the adjusting ring 5 of the adjusting component moves equidistantly closer to the nozzle 19, the contact area between the wall of the limiting groove and the edge of the conical mist beam shrinks, weakening the constraint on the conical mist beam and increasing the diffusion angle, thus expanding the spray range. This operation process, through the coordinated action of the liquid inlet component, pneumatic component, and control mechanism (adjusting ring 5, adjusting component, and contour electrode 6), achieves stable solution delivery and atomized spraying. It also enables precise and continuous adjustment of the spray range through the cooperation of the adjusting component and the frustum-shaped limiting groove. Simultaneously, the synergy between the limiting groove's blocking and the electrostatic atomization of the contour electrode 6 improves the uniformity of droplet size, ensuring printing quality and scene adaptability.

[0047] In this embodiment, when the contour electrode 6 is energized, a preset voltage is applied to the two symmetrical contour electrodes 6 according to the viscosity, surface tension, and other characteristics of the printing solution. A uniform symmetrical electrostatic field is formed between the electrodes, and the direction of the electric field is consistent with the spray direction of the conical mist. When the conical mist enters the electrostatic field, after being limited by the inner ring channel 12 of the adjusting ring 5, the conical mist, whose edge-dispersed droplets are initially constrained, passes through the electrostatic field region between the two contour electrodes 6 at a uniform speed along the axial direction. At this time, the droplets are atomized by electrostatic force, and the droplets in the mist (including tiny droplets and incompletely refined droplets) are electrostatically atomized. Induction charging occurs in the field, and under the influence of Coulomb force, the surface tension of the droplets is stretched, tearing larger droplets into multiple smaller droplets with more uniform particle size, achieving further atomization. After atomization, the mist stream is oriented and regularized. The charged micro-droplets are subjected to directional electric field force in the uniform electrostatic field, correcting the spray trajectory and preventing mist stream divergence, forming a more directional and refined mist stream. When atomization parameters need to be dynamically adapted, adjustments can be made according to the characteristics of the printing solution or the spray range. The input voltage of the contour electrode 6 can be adjusted to change the electric field strength, matching the atomization requirements under different working conditions and ensuring stable atomization effect. Through the progressive process of "uniform electric field construction - droplet charging and force - refinement + orientation", secondary refined atomization of the conical mist stream is achieved, improving the uniformity of droplet size, while regularizing the mist stream trajectory and avoiding edge droplet dispersion, providing a guarantee for accurate printing.

[0048] To address the constraint on the spray range of the solution ejected in a cone-shaped mist jet within the nozzle 19 via the limiting groove, this embodiment provides the following solution.

[0049] like Figure 1 , Figure 2 and Figure 10 As shown, multiple limiting grooves are provided in a stepped manner on the inner wall of the inner ring channel 12 from the nozzle 19 toward the adjusting ring 5, with the second limiting groove 11 and the first limiting groove 10 recessed in a stepwise manner. The first limiting groove 10 and the second limiting groove 11 are both provided with guide grooves 13 evenly opened along the generatrix direction. The guide grooves are connected to the pneumatic components through auxiliary parts.

[0050] At the start of the printing operation in this embodiment, the gas output from the pneumatic component is diverted by the auxiliary component to the guide grooves 13 of the first limiting groove 10 and the second limiting groove 11, forming a directional airflow along the generatrix of the guide groove 13. The conical mist jet ejected from the nozzle 19 first enters the second limiting groove 11, where the discrete droplets at the edge of the mist jet contact the groove wall and are initially blocked. At the same time, the directional airflow in the guide groove 13 provides auxiliary constraint to the mist jet along the generatrix of the groove wall, reducing the random diffusion of droplets. Subsequently, the mist jet enters the first limiting groove 10, where the stepped structure further enhances the blocking constraint of the groove wall on the mist jet. The airflow in the guide groove 13 of the first limiting groove 10 and the airflow in the second limiting groove 11 form a progressively regular pattern, making the mist jet shape more concentrated. When the adjustment component drives the adjusting ring 5 away from the nozzle 19, the contact area between the second limiting groove 11 and the first limiting groove 10 and the mist jet expands synchronously. The airflow coverage of the guide grooves 13 of the two grooves widens accordingly, and the blocking effect of the groove wall is enhanced in synergy, further limiting the diffusion angle of the mist jet. The spray range is reduced by adjusting the ring 5 to the nozzle 19. When the ring 5 approaches the nozzle 19, the contact area shrinks, the airflow constraint of the guide groove 13 weakens, and the spray beam diffusion angle increases to expand the spray range. The airflow pressure input to the guide groove 13 is adjusted by the pneumatic component according to the viscosity of the printing solution and the spray range requirements, so that the airflow intensity of the guide groove 13 matches the constraint effect of the limiting groove wall, avoiding excessive airflow causing the spray beam to deviate or insufficient airflow causing constraint failure. The first limiting groove 10 and the second limiting groove 11, which are distributed in a stepped manner, form a progressive mechanical barrier. Combined with the directional airflow introduced by the auxiliary component through the guide groove 13 of the two groove walls, the pneumatic auxiliary constraint is achieved, thus constructing a dual constraint mechanism of "stepped mechanical barrier + regular airflow in the direction of the generatrix". At the same time, it works in conjunction with the adjustment action of the adjustment component to strengthen the constraint effect on the droplets at the edge of the conical spray beam, and avoid the droplets from sticking to the groove wall through airflow assistance. It can also adapt to different spray range requirements to achieve dynamic adjustment, improve the stability of the spray beam shape and the accuracy of spray range adjustment.

[0051] Example 2: Regarding the distance between the control adjustment ring 5 and the nozzle 19 of the distance adjustment component, this example provides the following solution.

[0052] like Figure 1 and Figure 8 As shown, the distance adjustment assembly includes a mounting ring 2 sleeved on the end of the nozzle 19 on the nozzle body 1, a control ring 3 rotatably mounted on the outer ring of the mounting ring 2 via a positioning component, two control rods 7 symmetrically and vertically mounted on the outer ring of the adjustment ring 5, a slide rod 8 vertically mounted on the end face of the mounting ring 2 along the axis of the parallel adjustment ring 5, and a distance adjustment component mounted on the control ring 3 and controlling the adjustment ring 5 to slide along the length of the slide rod 8. The slide rod 8 movably passes through the body of the control rod 7.

[0053] In this embodiment, the mounting ring 2 is sleeved and fixed to the end of the nozzle body 1 where the nozzle 19 is located. This ensures that the control ring 3 is rotated and assembled onto the outer ring of the mounting ring 2 via the positioning component. Two control rods 7 are symmetrically and vertically fixed to the outer ring surface of the adjusting ring 5. The sliding rod 8 is vertically fixed to the end face of the mounting ring 2 along the axis parallel to the adjusting ring 5, and the sliding rod 8 moves through the rod body of the control rod 7. This allows the adjusting ring 5 to maintain its initial parallel posture with the nozzle 19 through the cooperation of the control rod 7 and the sliding rod 8. The adjusting component precisely cooperates with the control ring 3 and the adjusting ring 5 to ensure smooth transmission. The control ring 3 is rotated manually or through a drive mechanism. The adjusting component on the control ring 3 converts the rotational motion into linear driving force, causing the adjusting ring 5 to slide smoothly along the length of the sliding rod 8 (i.e., the axial direction of the nozzle 19) via the control rod 7. When the control ring 3 rotates in the opposite direction, the adjusting component drives the adjusting ring 5 along the sliding rod 8. The control ring 3 moves away from the nozzle 19, which, in conjunction with the limiting groove, reduces the spray range. When the control ring 3 rotates forward, the adjusting element drives the adjusting ring 5 to move along the slide bar 8 towards the nozzle 19, thus expanding the spray range. When the adjusting ring 5 reaches the target position, the positioning element automatically resets and locks the relative position of the control ring 3 and the mounting ring 2, preventing the adjusting ring 5 from shifting during the printing process. The mounting ring 2 provides a stable assembly base, and the control ring and adjusting element convert the rotational motion into the linear motion of the adjusting ring 5. The two symmetrically distributed control rods 7 and the guide of the slide bar 8 ensure that the adjusting ring 5 always moves parallel to the axis of the nozzle 19, avoiding deviation and skew. This achieves precise and continuous adjustment of the distance between the adjusting ring 5 and the nozzle 19, providing stable structural support for the limiting groove's constraint on the conical mist stream, and ensuring the accuracy and reliability of the spray range adjustment.

[0054] It is understandable that the relative position between control ring 3 and mounting ring 2 can be determined in various ways. This embodiment provides the following solution:

[0055] like Figure 8 and Figure 9 As shown, the outer ring surface of the mounting ring 2 has multiple buffer grooves 32 arranged in a circular array. The positioning component includes multiple positioning balls 34 that are inserted into the openings of the buffer grooves 32 through an elastic structure. The inner ring surface of the control ring 3 has multiple positioning holes 35 that correspond to the multiple positioning balls 34. The elastic structure is a buffer spring 33 inserted into the buffer groove 32, and the two ends of the buffer spring 33 are respectively connected to the bottom wall of the buffer groove 32 and the positioning ball 34.

[0056] In this embodiment, when the control ring 3 needs to be rotated for distance adjustment, an external force is applied to drive the control ring 3 to rotate relative to the mounting ring 2. The edge of the positioning hole 35 on the inner ring surface of the control ring 3 presses against the positioning ball 34. After being compressed, the positioning ball 34 compresses the buffer spring 33 in the buffer groove 32 and gradually retracts into the buffer groove 32, releasing the engagement and locking between the positioning ball 34 and the positioning hole 35, allowing the control ring 3 to rotate smoothly. During the rotation of the control ring 3, the positioning ball 34 always slides against the inner ring surface of the control ring 3 under the elastic force of the buffer spring 33. When the control ring 3 rotates to the next set of positioning holes 35 aligned with the positioning ball 34, the buffer spring 33 resets and pushes the positioning ball 34 into the corresponding positioning hole 35, forming a clear feedback point, which makes it easy for the operator to perceive the adjustment position and achieve precise control of the movement distance of the adjustment ring 5. When the adjustment ring 5 moves to the target position (corresponding to the spray range being met), the rotation of the control ring stops. 3. At this time, the positioning ball 34 is stably embedded in the currently aligned positioning hole 35 under the preload of the buffer spring 33. The elastic support of the buffer spring 33 restricts the positioning ball 34 from falling out, thereby locking the relative position of the control ring 3 and the mounting ring 2, preventing the control ring 3 from rotating and the adjusting ring 5 from shifting due to vibration and other factors during the printing process. Through the coordinated cooperation of the buffer groove 32, the buffer spring 33, the positioning ball 34 and the positioning hole 35, a positioning mechanism of "elastic engagement - pressure unlocking - locking point positioning - elastic locking" is constructed. This not only realizes smooth unlocking and gear feedback when the control ring 3 rotates and adjusts, but also provides reliable positioning and fixation after adjustment, preventing the adjusting ring 5 from shifting. At the same time, the buffer spring 33 can buffer the impact force when the positioning ball 34 and the positioning hole 35 are engaged, reduce component wear, ensure the stability and service life of the positioning structure, and provide reliable positioning support for the precise adjustment of the spray range.

[0057] In this embodiment, the buffer spring 33 is preferably made of spring steel or stainless steel.

[0058] The adjusting ring 5 of the adjusting component is moved. This embodiment provides the following solution:

[0059] like Figures 1-3 and Figure 8 As shown, the adjusting component includes an adjusting rod 31 vertically disposed on the bottom side of the control rod 7, and a rotating column rotatably disposed on the bottom end of the adjusting rod 31 near the side of the control ring 3. An adjusting groove 30 sleeved on the rotating column is provided on the inner ring of the control ring 3, and the distance between the two ends of the opening of the adjusting groove 30 along the axial direction of the control ring 3 is the sum of the depths of the first limiting groove 10 and the second limiting groove 11.

[0060] In this embodiment, when the control ring 3 is rotated, the adjusting groove 30 on its inner ring rotates synchronously with the control ring 3. The groove wall of the adjusting groove 30 forms a sliding fit with the rotating column, converting the rotational motion of the control ring 3 into a linear driving force along the axial direction of the adjusting groove 30. This driving force is transmitted to the control rod 7 through the adjusting rod 31, thereby driving the adjusting ring 5 to slide smoothly along the length of the slide rod 8. When the control ring 3 rotates in the opposite direction, the adjusting groove 30 pushes the rotating column to move away from the nozzle 19. Through the linkage of the adjusting rod 31 and the control rod 7, the adjusting ring 5 moves away from the nozzle 19 synchronously until the rotating column abuts the groove end of the adjusting groove 30 away from the nozzle. At this time, the movement stroke of the adjusting ring 5 is exactly equal to the sum of the depths of the first limiting groove 10 and the second limiting groove 11, avoiding over-adjustment that would cause the limiting groove to fail to cooperate with the mist. When the control ring 3 rotates in the opposite direction... During rotation, the adjusting groove 30 pulls the rotating column towards the nozzle 19, causing the adjusting ring 5 to move towards the nozzle 19 synchronously until the rotating column abuts the end of the adjusting groove 30 near the nozzle, maximizing the spray range. The adjusting component, through the sliding cooperation between the adjusting groove 30 and the rotating column, constructs an efficient "rotation-linear" transmission mechanism, ensuring that the rotation of the control ring 3 can be smoothly converted into the axial movement of the adjusting ring 5. At the same time, by utilizing the precise matching of the axial distance of the adjusting groove 30 and the sum of the depths of the two limiting grooves, the maximum travel of the adjusting ring 5 is strictly limited, avoiding component collisions or constraint failures. Combined with the guiding effect of the slide rod 8, the parallelism and consistency of the movement of the adjusting ring 5 are further guaranteed, providing core transmission assurance for the precise and controllable adjustment of the spray range, while simplifying the operation logic and improving adjustment efficiency.

[0061] Example 3: Regarding the mist jet emitted by nozzle 19, this example provides the following solution.

[0062] like Figure 5 and Figure 6 As shown, a spray ring 4 is fixedly installed at the center of one end face of the nozzle 19 in the nozzle body 1, and multiple second air supply channels 27 connected to pneumatic components are opened on the side of the spray ring 4. The nozzle orifice of the nozzle 19 is directly opposite the inner ring of the spray ring 4. Multiple spiral grooves 28 in a spiral array are opened in the inner ring of the spray ring 4. The openings of the multiple spiral grooves 28 near the nozzle 19 end are respectively connected to the second air supply channels 27. Spiral plates 29 are vertically arranged on the bottom wall of the spiral grooves 28 along the length direction of the opening.

[0063] When the printing operation is started in this embodiment, the gas output by the pneumatic component is diverted through a preset channel (first sealing cavity, fixed pipe 26, etc.) to each of the second gas delivery channels 27, and is precisely delivered to the corresponding spiral groove 28 through the second gas delivery channel 27. After the gas enters the spiral groove 28, under the guidance of the spiral contour of the spiral groove 28 and the diversion action of the spiral plate 29, it flows and accelerates along the spiral trajectory, and finally sprays out from the inner ring of the spray ring 4, forming a spiral airflow that uniformly surrounds the nozzle 19. When the conical mist jet sprayed from the nozzle 19 just leaves the nozzle, it meets the spiral airflow sprayed from the inner ring of the spray ring 4. The spiral airflow forms a uniform aerodynamic constraint on the mist jet in a circling manner, which not only regulates the mist jet, but also... The initial shape is suppressed, and the mist is initially atomized by the airflow shear force, refining some of the larger droplets. The second air supply channel 27 of the spray ring 4 accurately guides the air, and the gas of the pneumatic component is transformed into a uniform spiral airflow by the synergistic design of the spiral groove 28 and the spiral plate 29. This achieves the dual function of "initial shaping + preliminary atomization" of the conical mist, which not only lays a stable foundation for the mechanical constraint of the limiting groove and the electrostatic atomization of the contour electrode, but also avoids mist deviation by the uniformity of the spiral airflow. At the same time, it dynamically adapts to the adjustment action of the adjustment ring 5, further improving the consistency of the droplet size and the printing stability during the adjustment of the spray range.

[0064] Regarding the internal structure of the nozzle body 1, this embodiment provides the following solution:

[0065] like Figure 5 and Figure 7 As shown, the nozzle body 1 has a cavity, and a partition column 21 is provided in the cavity to divide the two ends of the cavity into a first sealing cavity and a second sealing cavity in which a nozzle 19 is provided. A first air supply channel is provided on the partition column 21, which passes through the first sealing cavity and the second sealing cavity. The pneumatic component delivers gas to the inner ring of the spray ring 4 through the air inlet 18, the first air supply channel 23, the first sealing cavity and the second air supply channel 27 in sequence through the wall of the second sealing cavity. A liquid inlet column 24 connected to the partition column 21 passes through the second sealing cavity. The liquid inlet component controls the solution to pass through the liquid inlet 17 in the liquid inlet column 24 and the first liquid supply channel 22 in the partition column 21 in sequence to the spray cavity 20 opened by the nozzle 19.

[0066] When the printing operation is started in this embodiment, the liquid inlet assembly controls the printing solution to enter the liquid inlet hole 17 of the liquid inlet column 24. The solution flows along the liquid inlet hole 17 through the first liquid delivery channel 22 of the separator column 21, and is finally accurately delivered to the spray chamber 20 of the nozzle 19 for storage before spraying. At the same time, the pneumatic assembly starts to supply air. The gas enters the second sealed chamber through the air inlet hole 18 in the wall of the second sealed chamber, and then flows into the first sealed chamber through the first gas delivery channel 23 on the separator column 21. After the airflow is evenly distributed in the first sealed chamber, it is diverted to each of the second gas delivery channels 27 of the spray ring 4, and finally delivered to the inner ring of the spray ring 4. The isolation design of the separator column 21 makes the solution delivery and gas delivery completely independent, avoiding mutual interference between gas and liquid inside the printhead body 1. At the same time, the first sealed chamber provides a buffer space for gas diversion, ensuring that the airflow pressure entering each of the second gas delivery channels 27 is uniform. Uniform; after the solution fills the spray chamber 20 of nozzle 19 and the gas is stably delivered to the inner ring of spray ring 4 through the second gas delivery channel 27, the pneumatic component further pressurizes and pushes the solution in the spray chamber 20 to be sprayed out of nozzle 19. At the same time, a spiral airflow is formed in the inner ring of spray ring 4, starting the subsequent atomization and constraint process; independent first and second sealed chambers are constructed through the separator column 21, and with the dedicated first liquid delivery channel 22 and first gas delivery channel 23, the solution and gas are separated and accurately delivered, avoiding the instability of the mist caused by gas-liquid interference. At the same time, the airflow buffering effect of the first sealed chamber ensures the uniformity of the spiral airflow, and the directional delivery of the liquid inlet channel ensures a stable supply of solution to nozzle 19, providing a stable and reliable gas-liquid supply basis for the subsequent formation of conical mist, atomization and spray range adjustment, and improving the overall stability and controllability of the nozzle operation.

[0067] Regarding the connection method between the second air supply channel and the pneumatic components, this embodiment provides the following solution:

[0068] like Figure 7 As shown, the second air supply channel 27 is connected to the pneumatic assembly via a connector. The connector includes a connecting ring 25 disposed in the first sealing cavity and sleeved on the nozzle 19, and a plurality of fixed tubes 26 arranged in a circumferential array on one end face of the connecting ring 25. The plurality of fixed tubes 26 are sealed and passed through one end opening of the plurality of second air supply channels 27, and the side of the connecting ring 25 has an opening that communicates with the interior of the plurality of fixed tubes 26.

[0069] In this embodiment, the gas output from the pneumatic component flows into the first sealed cavity through the first gas delivery channel 23, forming a stable pressure field within the cavity. The gas then uniformly converges into the interior of the connecting ring 25 through the opening on its side, achieving initial convergence of airflow and pressure buffering, thus avoiding pressure fluctuations caused by localized airflow concentration. The gas inside the connecting ring 25 is precisely divided through multiple fixed tubes 26 arranged in a circumferential array. Each fixed tube 26 independently and directionally delivers the gas to its corresponding second gas delivery channel 27. Due to the sealed fit between the fixed tubes 26 and the second gas delivery channel 27, gas leakage is prevented and the airflow pressure in each channel is consistent. The divided gas is continuously delivered through the second gas delivery channel 27 to the spiral groove 28 of the injection ring 4, providing a uniform gas source for the formation of the spiral airflow. Simultaneously, the rigid fit between the connecting ring 25 and the second gas delivery channel 27 through the fixed tubes 26 further reinforces the relative position of the injection ring 4 and the nozzle 19, preventing... The design avoids airflow impact or printing vibration that could cause the spray ring 4 to shift. When it is necessary to repair the air circuit or replace components, the connecting ring 25 can be directly removed by separating the second air supply channel 27 from the pneumatic component, and the fixed tube 26 can be driven to detach from the second air supply channel 27, thus achieving rapid disassembly of the connector and the air circuit and reducing the difficulty of maintenance operations. Through the integrated design of the connecting ring 25 and the circumferential array fixed tube 26, the "convergence-diversion" precise control of the airflow in the first sealing cavity is realized, ensuring that the airflow pressure in each second air supply channel 27 is uniform and stable, laying the core foundation for the uniformity of the subsequent spiral airflow. The sealing cooperation between the fixed tube 26 and the second air supply channel 27 strengthens the air circuit sealing performance, avoiding the atomization effect attenuation caused by gas leakage. At the same time, it also has the auxiliary function of reinforcing the position of the spray ring 4, improving the stability of the nozzle structure, and simplifying the disassembly and maintenance process of the air circuit components, achieving a dual improvement in operational reliability and ease of operation.

[0070] It is understood that gas can be supplied into the connection hole 14 in various ways. This embodiment provides the following solution:

[0071] like Figures 1-5 and Figure 10 As shown, the adjusting ring 5 has a collecting cavity that communicates with multiple connecting holes 14. The nozzle body 1 has a first conveying hole 15 that communicates with the first sealing cavity on the end face of the nozzle 19. When the mounting ring 2 is installed on the end face of the nozzle body 1, the mounting ring 2 has a second conveying hole 16 that communicates with the first conveying hole 15. The auxiliary component includes a connecting pipe 9 with its two ends installed on the mounting ring 2 and the adjusting ring 5 respectively. The connecting pipe 9 communicates with the second conveying hole 16 and the collecting cavity.

[0072] In this embodiment, the gas delivered to the first sealed cavity by the pneumatic component, in addition to being diverted to the fixed pipe 26 of the connector, part of the gas flows into the second delivery hole 16 of the mounting ring 2 through the first delivery hole 15, and is then directionally delivered to the collecting cavity of the adjusting ring 5 through the connecting pipe 9, realizing the branching distribution of the gas path; the gas entering the collecting cavity first completes the convergence buffer to avoid airflow fluctuations, and then is evenly diverted through multiple connecting holes 14 that communicate with the collecting cavity, and accurately delivered to each guide groove 13 of the first limiting groove 10 and the second limiting groove 11 groove wall; the gas in the guide groove 13 forms a directional airflow along the generatrix direction, which, together with the mechanical blocking effect of the limiting groove wall, provides double constraint on the discrete droplets at the edge of the conical mist beam passing through the inner ring channel 12, thereby enhancing the... The system effectively constrains the liquid droplets while preventing them from adhering to the tank wall. When maintenance of this branch gas path is required, the connection ends of the detachable connecting pipe 9 and the mounting ring 2 and adjusting ring 5 can be quickly separated to reduce maintenance difficulty. A dedicated branch gas path is constructed through the first delivery hole 15, the second delivery hole 16, the connecting pipe 9, the collecting cavity, and the connecting hole 14 to achieve precise and stable delivery of gas from the pneumatic components to the guide tank 13, providing a uniform directional airflow to the guide tank 13. This, together with the mechanical obstruction of the limiting tank wall, forms a dual constraint mechanism of "mechanical + pneumatic," enhancing the fog beam constraint effect and uniformity. At the same time, the connecting pipe 9 is adapted to the movement stroke of the adjusting ring 5 to ensure that the gas path is continuous and uninterrupted during the adjustment process, taking into account the constraint reliability, adjustment adaptability, and maintenance convenience.

[0073] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An electrostatic inkjet printhead with adjustable spray range, comprising a printhead body (1) with a nozzle (19) at one end, a liquid inlet assembly disposed on the printhead body (1), a pneumatic assembly disposed on the printhead body (1) and controlling the liquid spray, and a control mechanism disposed on the printhead body (1) to control the spray range, characterized in that, The control mechanism includes an adjustment ring (5) arranged parallel to the nozzle (19) at the end away from the nozzle body (1), an adjustment component arranged on the nozzle body (1) and controlling the adjustment ring (5) to be equidistant from or away from the nozzle (19), and two contour electrodes (6) symmetrically arranged on both sides of the end face of the adjustment ring (5) away from the nozzle (19). The inner wall of the inner ring channel (12) of the adjustment ring (5) is provided with multiple limiting grooves in a stepped manner from the nozzle (19) toward the adjustment ring (5). Each limiting groove is a frustum-shaped structure, and the opening of the limiting groove near the nozzle (19) is smaller than the opening away from the nozzle (19). During the spraying process, the liquid inlet assembly controls the solution to enter the nozzle (19), and the pneumatic assembly applies air pressure to the nozzle body (1) to drive the solution in the nozzle (19) to be sprayed out in the form of a cone-shaped mist. The sprayed cone-shaped mist passes through the inner ring channel (12), and the discrete droplets at the edge of the mist form contact with the wall of the limiting groove and are blocked. Then it passes between the two contour electrodes (6). The contour electrodes (6) generate an electrostatic field when energized, which further atomizes the cone-shaped mist. When adjusting the spray range, the distance adjustment component controls the adjustment ring (5) to move away from the nozzle (19). At this time, the contact area between the groove wall of the limiting groove and the edge of the conical mist beam expands, constraining the conical mist beam, limiting the diffusion angle, and reducing the spray range.

2. The electrostatic inkjet printhead with adjustable spray range according to claim 1, characterized in that: Multiple limiting grooves are inner ring channels (12) with the inner wall of the inner ring channel (12) recessed in a stepped manner from the nozzle (19) toward the adjusting ring (5) with the second limiting groove (11) and the first limiting groove (10). The first limiting groove (10) and the second limiting groove (11) are both uniformly provided with guide grooves (13) opened along the generatrix direction. The guide grooves are connected to the pneumatic components through auxiliary parts.

3. The electrostatic inkjet printhead with adjustable spray range according to claim 1 or 2, characterized in that: The distance adjustment assembly includes a mounting ring (2) fitted on the nozzle body (1) and the end of the nozzle (19), a control ring (3) rotatably mounted on the outer ring of the mounting ring (2) via a positioning element, two control rods (7) symmetrically and vertically mounted on the outer ring of the adjustment ring (5), a slide rod (8) vertically mounted on the end face of the mounting ring (2) along the parallel axis of the adjustment ring (5), and a distance adjustment element mounted on the control ring (3) and controlling the adjustment ring (5) to slide along the length of the slide rod (8). The slide rod (8) moves through the body of the control rod (7).

4. The electrostatic inkjet printhead with adjustable spray range according to claim 3, characterized in that: The mounting ring (2) has multiple buffer grooves (32) arranged in a circular array on its outer ring surface. The positioning element includes multiple positioning balls (34) that are inserted into the opening of the buffer groove (32) through an elastic structure. The control ring (3) has multiple positioning holes (35) that correspond to the multiple positioning balls (34) on its inner ring surface.

5. The electrostatic inkjet printhead with adjustable spray range according to claim 4, characterized in that: The adjusting component includes an adjusting rod (31) vertically disposed on the bottom side of the control rod (7) and a rotating column rotatably disposed on the bottom end of the adjusting rod (31) near the side of the control ring (3). An adjusting groove (30) sleeved on the rotating column is provided on the inner ring of the control ring (3), and the distance between the two ends of the opening of the adjusting groove (30) along the axial direction of the control ring (3) is the sum of the depths of the first limiting groove (10) and the second limiting groove (11).

6. The electrostatic inkjet printhead with adjustable spray range according to claim 1 or 2, characterized in that: The nozzle body (1) is fixedly provided with a spray ring (4) at the center of one end face of the nozzle (19), and multiple second air supply channels (27) connected to the pneumatic components are opened on the side of the spray ring (4). The nozzle (19) nozzle orifice is directly opposite the inner ring of the spray ring (4).

7. The electrostatic inkjet printhead with adjustable spray range according to claim 5, characterized in that: The inner ring of the injection ring (4) is arranged in a circular array with multiple spiral grooves (28) in a spiral state. The openings of the multiple spiral grooves (28) near the nozzle (19) are respectively connected to the second gas delivery channel (27). A spiral plate (29) is arranged vertically on the bottom wall of the spiral groove (28) along the length direction of the opening.

8. The electrostatic inkjet printhead with adjustable spray range according to claim 6, characterized in that: The nozzle body (1) has a cavity, and a partition column (21) is provided in the cavity to divide the two ends of the cavity into a first sealing cavity and a second sealing cavity with a nozzle (19) inside. A first air supply channel is provided on the partition column (21) to pass through the first sealing cavity and the second sealing cavity. The pneumatic component delivers gas to the inner ring of the spray ring (4) through the air inlet (18), the first air supply channel (23), the first sealing cavity and the second air supply channel (27) opened in the wall of the second sealing cavity. A liquid inlet column (24) connected to the partition column (21) is provided in the second sealing cavity. The liquid inlet component controls the solution to pass through the liquid inlet hole (17) opened in the liquid inlet column (24) and the first liquid supply channel (22) opened in the partition column (21) to the spray cavity (20) opened by the nozzle (19).

9. The electrostatic inkjet printhead with adjustable spray range according to claim 8, characterized in that: The second air supply channel (27) is connected to the pneumatic assembly via a connector. The connector includes a connecting ring (25) disposed in the first sealing cavity and sleeved on the nozzle (19), and a plurality of fixed tubes (26) arranged in a circumferential array on one end face of the connecting ring (25). The plurality of fixed tubes (26) are sealed and inserted into one end opening of the plurality of second air supply channels (27) respectively. The side of the connecting ring (25) has an opening that communicates with the interior of the plurality of fixed tubes (26).

10. The electrostatic inkjet printhead with adjustable spray range according to claim 9, characterized in that: The adjusting ring (5) has a collection cavity that communicates with multiple connecting holes (14). The nozzle body (1) has a first conveying hole (15) that communicates with the first sealing cavity on the end face of the nozzle (19). When the mounting ring (2) is installed on the end face of the nozzle body (1), the mounting ring (2) has a second conveying hole (16) that communicates with the first conveying hole (15). The auxiliary component includes a connecting pipe (9) with both ends installed on the mounting ring (2) and the adjusting ring (5), respectively. The connecting pipe (9) communicates with the second conveying hole (16) and the collection cavity.

Images