Ink nozzle internal circulation structure of bending type piezoelectric ink-jet printing head

Abstract

The invention relates to the technical field of printing head ink nozzles, and discloses a bent piezoelectric ink-jet printing head ink nozzle internal circulation structure which comprises a nozzle module and further comprises an inlet main ink channel arranged on one side in the nozzle module and an outlet main ink channel arranged on the other side in the nozzle module. And the multiple groups of pressure cavities are arranged at the top of the nozzle module and are positioned between the inlet main ink channel and the outlet main ink channel. According to the internal circulation structure of the ink nozzle of the bending type piezoelectric ink-jet printing head, the first transverse flow channel, the vertical flow channel and the second transverse flow channel are arranged on the two sides of the pressure cavity to form an internal circulation flow channel, so that continuous local flow of ink is formed in a spraying hole area, small particles can be scoured and taken away in real time, the blocking risk is fundamentally reduced, and the working efficiency is improved. And meanwhile, the circulating flow channel is integrated in the single nozzle unit, does not need to depend on a huge external circulating system, is compact in structure and is easy to realize multi-nozzle array integration.

Description

Technical Field

[0001] This invention relates to the field of printhead ink nozzle technology, and more particularly to a curved piezoelectric inkjet printhead ink nozzle internal circulation structure. Background Technology

[0002] Piezoelectric inkjet printing technology, with its advantages of high precision and non-contact printing, has been widely used in industrial 3D printing, precision electronic coating, textile printing and bioprinting. Its core component, the piezoelectric inkjet printhead, drives ink to be ejected from a micron-level nozzle through the periodic deformation of piezoelectric elements, which requires extremely high ink purity and flow channel stability.

[0003] However, in actual use, tiny particles or agglomerates in the ink can easily deposit in the pressure chamber or nozzle of the nozzle, causing nozzle blockage, uneven ink spraying, broken lines, or even printhead failure, which seriously affects print quality and equipment reliability. Currently common methods for preventing blockages mainly include: System-level ink circulation: A main circulation loop is set up in the ink supply system to make the ink flow outside the entire printhead. This method has limited cleaning effect on local nozzles, and it is particularly difficult to remove particles that have entered the pressure chamber. In addition, the system structure is complex and the energy consumption is high.

[0004] Regular cleaning procedures: This involves flushing with cleaning fluid via an external pump or by increasing the inkjet drive voltage. This method impacts printing efficiency and cannot prevent clogging in real time; it should only be used as a reactive maintenance measure.

[0005] Optimize nozzle structure: such as increasing the nozzle diameter or simplifying the flow channel, which can reduce the probability of clogging, but will reduce printing accuracy and droplet control.

[0006] In addition, most existing printheads adopt a straight-through flow channel design, which results in weak ink flow in the pressure chamber and easy particle settling. Although some attempts have been made to introduce micro-flow structures near the nozzle, these often rely on complex external drives or affect normal inkjet performance, making it difficult to achieve efficient and real-time anti-clogging while ensuring print quality. Summary of the Invention

[0007] Given that most existing printheads adopt a straight-through flow channel design, the ink has weak flow in the pressure chamber and particles are prone to settling. Although some attempts have been made to introduce micro-flow structures near the nozzle, these often rely on complex external drives or affect normal inkjet performance, making it difficult to achieve efficient and real-time anti-clogging while ensuring print quality. Therefore, this invention is proposed.

[0008] Therefore, the purpose of this invention is to provide a curved piezoelectric inkjet printhead ink nozzle internal circulation structure, the purpose of which is to design a nozzle anti-clogging solution that is compact, effective in real time, and does not affect printing accuracy, and is especially suitable for high-requirement industrial printing scenarios.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a curved piezoelectric inkjet printhead ink nozzle internal circulation structure, including a nozzle module, an inlet main ink channel disposed on one side inside the nozzle module, an outlet main ink channel disposed on the other side inside the nozzle module, multiple pressure chambers disposed on the top of the nozzle module and located between the inlet main ink channel and the outlet main ink channel, and multiple first transverse flow channels disposed inside the nozzle module and located between the pressure chambers and the inlet main ink channel, wherein one end of the first transverse flow channel is connected to the pressure chamber, and the first transverse flow channel is away from the pressure chamber. One end of the cavity is connected to the main inlet ink channel. A vertical flow channel is located inside the nozzle module and below the pressure chamber, and the top end of the vertical flow channel is connected to the inner cavity of the pressure chamber. Multiple sets of nozzles are located at the bottom of the nozzle module and between the main inlet ink channel and the main outlet ink channel, and the nozzles are connected to the bottom end of the vertical flow channel. Multiple sets of second transverse flow channels are located inside the nozzle module and between the vertical flow channel and the main outlet ink channel, and one end of the second transverse flow channel is connected to the vertical flow channel. The end of the second transverse flow channel away from the vertical flow channel is connected to the inner cavity of the main outlet ink channel.

[0010] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, the nozzle module has multiple sets of ink inlets on the top side near the main ink channel, and the ink inlets and the main ink channel are interconnected; the nozzle module also has multiple sets of ink outlets on the top side near the main ink channel, and the ink outlets and the main ink channel are interconnected.

[0011] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, a first flow limiter is provided at the end of the inner cavity of the first transverse flow channel near the pressure chamber, and a second flow limiter is provided at the end of the inner cavity of the second transverse flow channel near the main ink channel at the outlet.

[0012] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, a positioning frame is fixedly installed at both ends and both sides of the inner cavity of the pressure chamber, a vibrating plate is disposed above the positioning frame, and a limiting frame is disposed above the vibrating plate.

[0013] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, a limiting plate is provided above the nozzle module, and multiple sets of mounting seats are provided at the bottom of the limiting plate, with the bottom end of the mounting seats extending into the inner cavity of the pressure chamber.

[0014] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, the mounting base is provided with a mounting frame at its bottom end, and a piezoelectric ceramic sheet is disposed on the inner sidewall of the mounting frame.

[0015] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, the nozzle module has limit slots on both sides of its top, a threaded hole on one side of the inner cavity of the limit slot, the limit plate is inverted U-shaped, and both ends of the limit plate extend to the inner side of the limit slot, placement slots are provided on both sides of the limit plate, and a fixing bolt is provided on one side of the inner cavity of the placement slot, with one end of the fixing bolt penetrating the limit plate and extending into the threaded hole.

[0016] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, the pressure chamber has two sets of limiting grooves on both sides, two sets of first limiting sliders are provided on both sides of the limiting frame and the first limiting sliders are slidably connected to the inner cavity of the limiting groove, and two sets of second limiting sliders are provided on both sides of the mounting base and the second limiting sliders are slidably connected to the inner cavity of the limiting groove.

[0017] As a preferred embodiment of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead described in this invention, the cross-section of the limiting groove is T-shaped, the first limiting slider and the second limiting slider are both T-shaped, and the first limiting slider and the second limiting slider are adapted to the limiting groove.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention forms an internal circulation channel by setting a first transverse flow channel, a vertical flow channel, and a second transverse flow channel on both sides of the pressure chamber, so that the ink forms a continuous local flow in the nozzle area, which can flush and carry away tiny particles in real time, fundamentally reducing the risk of clogging. It is particularly suitable for inks that are prone to clogging, such as those containing particles and high viscosity. At the same time, the circulation channel is integrated inside a single nozzle unit, without relying on a large external circulation system. The structure is compact and easy to integrate into multiple nozzle arrays, making it suitable for high-resolution printhead designs.

[0019] 2. The real-time self-cleaning function of this invention reduces the frequency of cleaning and mechanical wear caused by strong cleaning, significantly improving the service life of the printhead and making it suitable for industrial scenarios with long-term continuous operation.

[0020] 3. This invention integrates multiple sets of piezoelectric ceramic plates onto a limiting plate, allowing for quick disassembly and replacement of the vibrating plate and piezoelectric ceramic plates within the pressure chamber. This also facilitates subsequent maintenance operations and improves its applicability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead of the present invention. Figure 2 This is a schematic diagram of the overall structure of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead of the present invention from another perspective. Figure 3 This is a schematic diagram of the unfolded three-dimensional structure of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead of the present invention. Figure 4 This is a cross-sectional three-dimensional structural diagram of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead of the present invention. Figure 5 This is a schematic diagram of the unfolded three-dimensional structure of the pressure chamber of the ink nozzle internal circulation structure of the curved piezoelectric inkjet printhead of the present invention. Figure 6 This is a cross-sectional three-dimensional structural schematic diagram of the pressure chamber of the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead of the present invention. Figure 7 This is a three-dimensional structural diagram of the mounting base for the internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Nozzle module; 2. Inlet main ink channel; 3. Outlet main ink channel; 4. Ink inlet; 5. Ink outlet; 6. First transverse flow channel; 7. Vertical flow channel; 8. Nozzle; 9. Second transverse flow channel; 10. First flow restrictor; 11. Second flow restrictor; 12. Pressure chamber; 13. Limiting plate; 14. Limiting slot; 15. Threaded hole; 16. Fixing bolt; 17. Positioning frame; 18. Vibrating plate; 19. Limiting frame; 20. Mounting base; 21. Mounting frame; 22. Piezoelectric ceramic plate; 23. Limiting groove; 24. First limiting slider; 25. Second limiting slider; 26. Placement slot. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Example 1

[0024] Reference Figures 1-7This invention provides a first embodiment of a curved piezoelectric inkjet printhead ink nozzle internal circulation structure. This structure includes a nozzle module 1, an inlet main ink channel 2 located on one side of the nozzle module 1, an outlet main ink channel 3 located on the other side of the nozzle module 1, multiple pressure chambers 12 located at the top of the nozzle module 1 between the inlet main ink channel 2 and the outlet main ink channel 3, and multiple first transverse flow channels 6 located inside the nozzle module 1 between the pressure chambers 12 and the inlet main ink channel 2. One end of each first transverse flow channel 6 is connected to a pressure chamber 12, and the first transverse flow channel 6 is located away from the pressure chamber 12. A vertical flow channel 7 is connected to the inlet main ink channel 2 at one end, is opened inside the nozzle module 1 and located below the pressure chamber 12, and the top of the vertical flow channel 7 is connected to the inner cavity of the pressure chamber 12. Multiple sets of nozzles 8 are opened at the bottom of the nozzle module 1 and located between the inlet main ink channel 2 and the outlet main ink channel 3, and the nozzles 8 are connected to the bottom of the vertical flow channel 7. The nozzles 8 are set to facilitate ink ejection. Multiple sets of second transverse flow channels 9 are set inside the nozzle module 1 and located between the vertical flow channel 7 and the outlet main ink channel 3, and one end of the second transverse flow channel 9 is connected to the vertical flow channel 7. The end of the second transverse flow channel 9 away from the vertical flow channel 7 is connected to the inner cavity of the outlet main ink channel 3.

[0025] Multiple sets of ink inlets 4 are provided on the top of the nozzle module 1 and on the side near the inlet main ink channel 2. The ink inlets 4 and the inlet main ink channel 2 are interconnected, which facilitates the entry of ink into the inner cavity of the inlet main ink channel 2. Multiple sets of ink outlets 5 are provided on the top of the nozzle module 1 and on the side near the outlet main ink channel 3. The ink outlets 5 and the outlet main ink channel 3 are interconnected, which facilitates the removal of ink from the outlet main ink channel 3 and the formation of a circulation.

[0026] Positioning frames 17 are fixedly installed at both ends and sides of the inner cavity of the pressure chamber 12. Vibrating plates 18 are installed above the positioning frames 17, and limiting frames 19 are installed above the vibrating plates 18. A limiting plate 13 is provided above the nozzle module 1. Multiple sets of mounting seats 20 are installed at the bottom of the limiting plate 13, and the bottom end of the mounting seats 20 extends into the inner cavity of the pressure chamber 12. The positioning frames 17 are used to limit the vibration plates 18.

[0027] The mounting base 20 has a mounting frame 21 installed at its bottom end, and a piezoelectric ceramic sheet 22 disposed on the inner side wall of the mounting frame 21.

[0028] A first flow limiter 10 is provided at the end of the inner cavity of the first transverse flow channel 6 near the pressure chamber 12. The first flow limiter 10 controls the ink flow rate and flow rate entering the pressure chamber 12, and provides a stable ink supply to the pressure chamber 12 to prevent ink from flowing in too quickly and causing pressure instability. A second flow limiter 11 is provided at the end of the inner cavity of the second transverse flow channel 9 near the outlet main ink channel 3. The second flow limiter 11 controls the ink flow rate and flow rate entering the outlet main ink channel 3 to prevent ink from flowing in too quickly and causing pressure instability.

[0029] During operation, the power of the entire internal circulation originates from the pressure gradient established by the printhead ink supply system. During printing, the main ink supply system maintains a stable, low-flow-rate ink circulation between the ink inlet 4 and the ink outlet 5. First, ink enters the main ink channel 2 through the ink inlet 4, and then is transported through multiple sets of first transverse channels 6. The first flow limiter 10 within the first transverse channel 6 controls the flow rate and volume of ink entering the pressure chamber 12, preventing excessive ink flow and resulting pressure instability. Simultaneously, the voltage drop triggers the piezoelectric ceramic plate 22 to extend downwards, and the vibrating plate 18 moves towards... The downward stretching reduces the volume of the pressure chamber 12, causing a sharp increase in pressure within the chamber. The ink in the pressure chamber 12 is pressure-diverted and ejected through the nozzle 8 on the vertical flow channel 7, completing the printing action. Due to the flow resistance regulation of the second horizontal flow channel 9 and the second flow limiter 11, some ink containing suspended particles in the chamber is forcibly guided by the second flow limiter 11 into the outlet main ink channel 3. Then, the piezoelectric ceramic sheet 22 is excited by the rising edge of the voltage, generating an inverse piezoelectric effect. The vibrating diaphragm is stretched upward, increasing the volume of the pressure chamber 12. The pressure inside the chamber is momentarily lower than atmospheric pressure. Driven by the pressure difference, the ink in the inlet main ink channel 2 flows steadily into the pressure chamber 12 through the first flow limiter 10 on the first horizontal flow channel 6. Example 2

[0030] Reference Figures 1-7 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that: the top of the nozzle module 1 has limit slots 14 on both sides, and threaded holes 15 are formed on one side of the inner cavity of the limit slots 14. The limit plate 13 is inverted U-shaped, and both ends of the limit plate 13 extend to the inner side of the limit slots 14. Placement slots 26 are provided on both sides of the limit plate 13, and fixing bolts 16 are provided on one side of the inner cavity of the placement slots 26. One end of the fixing bolt 16 passes through the limit plate 13 and extends into the threaded hole 15. The placement slots 26 are provided so that the fixing bolts 16 do not protrude on one side of the limit plate 13.

[0031] Two sets of limiting grooves 23 are provided on both sides of the inner cavity of the pressure chamber 12. Two sets of first limiting sliders 24 are provided on both sides of the limiting frame 19 and are slidably connected to the inner cavity of the limiting grooves 23. Two sets of second limiting sliders 25 are provided on both sides of the mounting base 20. The first limiting sliders 24 are used to conveniently limit the limiting frame 19, ensuring that the limiting frame 19 and the positioning frame 17 cooperate with each other to fix the vibrating plate 18. The second limiting sliders 25 are slidably connected to the inner cavity of the limiting grooves 23. The cross section of the limiting grooves 23 is T-shaped. The first limiting sliders 24 and the second limiting sliders 25 are both T-shaped and are adapted to the limiting grooves 23. The limiting grooves 23 are used to limit the movement trajectory of the limiting frame 19 and the mounting base 20.

[0032] During use, multiple sets of mounting bases 20 are installed on the limiting plate 13. When it is necessary to replace the vibrating plate 18 and the piezoelectric ceramic plate 22 in the pressure chamber 12 or to clean the pressure chamber 12, the fixing bolts 16 on both sides of the two sets of limiting plates 13 are turned out from the threaded holes 15 inside the limiting slot 14, thereby removing the fixing between the limiting plate 13 and the nozzle module 1. Then the limiting plate 13 can be removed from the nozzle module 1, and the multiple sets of mounting bases 20 can be removed from the pressure chamber 12 for convenient subsequent maintenance operations.

[0033] The remaining structure is the same as that in Example 1.

[0034] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A curved piezoelectric inkjet printhead ink nozzle internal circulation structure, comprising a nozzle module (1), characterized in that: It also includes an inlet main ink channel (2) disposed on one side inside the nozzle module (1), an outlet main ink channel (3) disposed on the other side inside the nozzle module (1), multiple pressure chambers (12) disposed on the top of the nozzle module (1) and located between the inlet main ink channel (2) and the outlet main ink channel (3), and multiple first transverse flow channels (6) disposed inside the nozzle module (1) and located between the pressure chambers (12) and the inlet main ink channel (2), wherein one end of the first transverse flow channel (6) is connected to the pressure chamber (12), and the end of the first transverse flow channel (6) away from the pressure chamber (12) is connected to the inlet main ink channel (2), and is disposed inside the nozzle module (1). The vertical flow channel (7) is located below the pressure chamber (12), and the top of the vertical flow channel (7) is connected to the inner cavity of the pressure chamber (12). Multiple sets of nozzles (8) are set at the bottom of the nozzle module (1) and located between the inlet main ink channel (2) and the outlet main ink channel (3), and the nozzles (8) are connected to the bottom of the vertical flow channel (7). Multiple sets of second transverse flow channels (9) are set inside the nozzle module (1) and located between the vertical flow channel (7) and the outlet main ink channel (3), and one end of the second transverse flow channel (9) is connected to the vertical flow channel (7). The end of the second transverse flow channel (9) away from the vertical flow channel (7) is connected to the inner cavity of the outlet main ink channel (3).

2. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 1, characterized in that: The nozzle module (1) has multiple sets of ink inlets (4) on the top and near the main ink channel (2), and the ink inlets (4) and the main ink channel (2) are interconnected. The nozzle module (1) has multiple sets of ink outlets (5) on the top and near the main ink channel (3), and the ink outlets (5) and the main ink channel (3) are interconnected.

3. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 1, characterized in that: A first flow limiter (10) is provided at the end of the inner cavity of the first transverse flow channel (6) near the pressure chamber (12), and a second flow limiter (11) is provided at the end of the inner cavity of the second transverse flow channel (9) near the outlet main ink channel (3).

4. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 1, characterized in that: Positioning frames (17) are fixedly installed at both ends and sides of the inner cavity of the pressure chamber (12), a vibrating plate (18) is set above the positioning frame (17), and a limiting frame (19) is set above the vibrating plate (18).

5. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 4, characterized in that: A limiting plate (13) is provided above the nozzle module (1), and multiple sets of mounting seats (20) are provided at the bottom of the limiting plate (13), with the bottom end of the mounting seat (20) extending into the inner cavity of the pressure chamber (12).

6. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 5, characterized in that: The mounting base (20) has a mounting frame (21) installed at its bottom end, and a piezoelectric ceramic sheet (22) disposed on the inner side wall of the mounting frame (21).

7. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 5, characterized in that: The nozzle module (1) has a limit slot (14) on both sides of its top, and a threaded hole (15) on one side of the inner cavity of the limit slot (14). The limit plate (13) is U-shaped and both ends of the limit plate (13) extend to the inner side of the limit slot (14). The limit plate (13) has a placement slot (26) on both sides of the limit plate (13) and a fixing bolt (16) on one side of the inner cavity of the placement slot (26). One end of the fixing bolt (16) passes through the limit plate (13) and extends into the threaded hole (15).

8. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 6, characterized in that: Two sets of limiting grooves (23) are provided on both sides of the inner cavity of the pressure chamber (12), two sets of first limiting sliders (24) are provided on both sides of the limiting frame (19), and the first limiting sliders (24) are slidably connected to the inner cavity of the limiting grooves (23), and two sets of second limiting sliders (25) are provided on both sides of the mounting base (20), and the second limiting sliders (25) are slidably connected to the inner cavity of the limiting grooves (23).

9. The internal circulation structure of the ink nozzle of the curved piezoelectric inkjet printhead according to claim 8, characterized in that: The cross section of the limiting groove (23) is T-shaped. The first limiting slider (24) and the second limiting slider (25) are both T-shaped, and the first limiting slider (24) and the second limiting slider (25) are adapted to the limiting groove (23).

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