Printing device and printing equipment

Abstract

The utility model discloses a printing device and printing equipment, the printing device comprises a body, the body is provided with a first inner wall and a circumferential inner wall, the first inner wall and the circumferential inner wall enclose a liquid cavity, the circumferential inner wall is provided with a liquid inlet, and the liquid inlet is communicated with the first inner wall in the direction from the liquid inlet to the first inner wall. The cross sectional area of the circumferential inner wall is gradually increased; the body is provided with at least one row of spray holes, the spray holes are communicated with the liquid cavity, and the linear distances from the spray holes in the same row to a liquid inlet point of the liquid inlet are equal. By designing the shape of the liquid cavity and the positions of the spray holes, the lengths of paths of ink entering from the liquid inlet flowing to the spray holes in the same row are equal, the pressure of the spray holes in the same row is ensured to be consistent, all the spray holes can stably spray liquid drops, and the printing quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of printing equipment, in particular to a printing device and printing equipment. Background Art

[0002] The printing mechanism is the core component of an inkjet printer, and its jetting performance directly impacts print quality. Typically, existing printing mechanisms experience varying lengths of liquid flow paths from the liquid inlet to each nozzle. The longer the liquid flow path, the greater the pressure loss. This results in significant pressure variations across nozzles, which in turn affects print quality. Utility Model Content

[0003] In response to the problems existing in the above-mentioned prior art, the present invention provides a printing device and a printing equipment. By designing the liquid cavity shape and the nozzle position, the straight-line distance from all nozzle holes in the same row to the liquid inlet is the same, so that the paths of ink entering from the liquid inlet to each nozzle hole in the same row are equal, thereby reducing the pressure difference between each nozzle hole in the same row and improving the printing quality.

[0004] To achieve the above purpose, the technical solution of the utility model is as follows:

[0005] The utility model provides a printing device, comprising a main body, wherein the main body is provided with a first inner wall and a circumferential inner wall, the first inner wall and the circumferential inner wall enclosing a liquid cavity, the circumferential inner wall being provided with a liquid inlet, and the cross-sectional area of ​​the circumferential inner wall gradually increases in the direction from the liquid inlet to the first inner wall; the main body is provided with at least one row of spray holes, the spray holes being connected to the liquid cavity, and the straight-line distances from the spray holes in the same row to the liquid inlet points of the liquid inlet are equal.

[0006] As an embodiment, the first inner wall is an arc-shaped surface, and the center line of the first inner wall coincides with or intersects perpendicularly with the central axis of the liquid inlet.

[0007] As an embodiment, the circumferential inner wall includes two second inner walls arranged opposite to each other and connected to the first inner wall, and two third inner walls arranged opposite to each other and connected to the first inner wall. The two second inner walls and the two third inner walls are connected to the circumferential edge of the first inner wall, and the third inner wall is connected to the second inner wall. The spray hole is provided on the second inner wall or the first inner wall, and an opening with gradually increasing width is formed between the two third inner walls in the direction from the liquid inlet to the first inner wall. The two third inner walls are symmetrically arranged about the plane passing through the central axis of the liquid inlet.

[0008] As an implementation form, the circumferential inner wall further comprises a fourth inner wall opposite to the first inner wall, the fourth inner wall connects two second inner walls and two third inner walls away from one end of the first inner wall, and the liquid inlet is arranged on the second inner wall or the fourth inner wall.

[0009] As an implementation form, the injection holes are arranged on the first inner wall in an arc shape, and the liquid inlet is arranged on the fourth inner wall.

[0010] And / or, the liquid inlet is arranged on the fourth inner wall, and the two third inner walls are tangent to the inner wall edge of the liquid inlet, respectively.

[0011] As an implementation form, the body is provided with two or more rows of injection holes arranged in a direction gradually away from the liquid inlet, the two second inner walls are arranged opposite to each other in a vertical direction, and one of them is a top wall surface and the other is a bottom wall surface, the injection holes are arranged on the bottom wall surface, the distances from the injection holes in different rows to the liquid inlet point are not equal, and the vertical distance between the top wall surface and the bottom wall surface gradually increases in a direction from the liquid inlet to the first inner wall.

[0012] As an implementation form, the body is further provided with a liquid outlet communicating with the liquid cavity, all the injection holes are located between the liquid outlet and the liquid inlet, and a projection point of any injection hole in a row of injection holes farthest from the liquid inlet to the top wall surface is a first position, and the height at which the liquid outlet is connected to the liquid cavity is not lower than the height of the first position.

[0013] As an implementation form, the body is further provided with a liquid outlet communicating with the liquid cavity, all the injection holes are located between the liquid outlet and the liquid inlet, and the height at which the liquid outlet is connected to the liquid cavity is not lower than the height at which the liquid inlet is connected to the liquid cavity.

[0014] As an implementation form, the first inner wall is an arc spherical surface, the spherical center of the first inner wall is on the central axis of the liquid inlet, the injection holes are arranged on the first inner wall, and the liquid inlet is arranged on one end of the circumferential inner wall away from the first inner wall.

[0015] As an implementation form, the circumferential inner wall comprises a conical inner wall connecting the circumferential edge of the first inner wall, and the conical inner wall is symmetrically arranged about a plane passing through the central axis of the liquid inlet.

[0016] And / or, the first inner wall is provided with two or more rows of injection holes, the distances from all the injection holes to the liquid inlet point are equal, and the adjacent two rows of injection holes are arranged in a staggered manner.

[0017] The utility model also provides a kind of printing equipment, including at least one printing device as any one of the above, thus have the same effect with printing spray device.

[0018] Compared with the prior art, the utility model has the following advantages after adopting the above structure:

[0019] The circumferential inner wall is provided with a liquid inlet, and the cross-sectional area of the circumferential inner wall gradually increases in the direction from the liquid inlet to the first inner wall; the body is provided with at least one row of spray holes, the spray holes are communicated with the liquid cavity, and the straight-line distance from the spray holes in the same row to the liquid inlet is equal. The utility model designs the shape of the liquid cavity and the position of the spray holes, so that the path length of the ink flowing from the liquid inlet to the spray holes in the same row is equal, the pressure difference of the spray holes in the same row is reduced, stable droplet ejection of all spray holes is ensured, and the printing quality is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of the three-dimensional structure of the embodiment one of the utility model;

[0021] Figure 2 is a bottom view of Figure 1 ;

[0022] Figure 3 is a front view of Figure 2 ;

[0023] Figure 4 is a rear view of Figure 1 ;

[0024] Figure 5 is a sectional view along B-B direction of Figure 4 ;

[0025] Figure 6 is a sectional view of another printing device of the utility model;

[0026] Figure 7 is a sectional view of another printing device of the utility model;

[0027] Figure 8 is a schematic diagram of the three-dimensional structure of the embodiment two of the utility model;

[0028] Figure 9 is a top view of Figure 8 ;

[0029] Figure 10 is a sectional view along C-C direction of Figure 9 .

[0030] Reference numerals: body 1; first inner wall 11; second inner walls 12, 13; third inner wall 14; fourth inner wall 15; liquid cavity 16; liquid inlet 17; liquid outlet 18; spray hole 19. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] Conventional printheads are equipped with a brake and an actuator connected to a chamber. Applying a discharge pulse to the actuator causes the chamber to contract and expand, causing the nozzles to eject droplets of printing liquid, such as ink, onto the print medium. While conventional methods can ensure the same discharge pressure across two nozzles at different distances from the inlet by adjusting the pulse width and drive voltage, this approach only works when the number of nozzles is small. Conventional printheads often have hundreds or even thousands of nozzles, and achieving consistent discharge pressure across such a large number of nozzles simply by adjusting the pulse width and drive voltage is extremely difficult, requiring complex testing, adjustments, and monitoring, which is not only time-consuming but also unpredictable. The present application directly improves the chamber shape and nozzle position, ensuring that the linear distance from the inlet to the liquid inlet point of nozzles in the same row is the same. This ensures that the fluid path length from the inlet to all nozzles in a row is equal, thereby achieving consistent pressure across all nozzles, making implementation simpler and more reliable.

[0033] <First embodiment>

[0034] like Figures 1-7 As shown, the utility model protects a printing device that is provided with only a row of nozzle holes 19 arranged in an arc shape for spraying printing droplets onto a printing medium. The printing droplets may be ink. The printing device includes a body 1, which is provided with a first inner wall 11 and a circumferential inner wall. The first inner wall 11 and the circumferential inner wall form a liquid cavity 16. The circumferential inner wall is provided with a liquid inlet 17. The cross-sectional area of ​​the circumferential inner wall gradually increases from the liquid inlet 17 to the first inner wall 11. The body 1 is provided with at least one row of nozzle holes 19, which are connected to the liquid cavity 16. The straight-line distance d from the nozzle holes 19 in the same row to the liquid inlet 17 is equal. The liquid inlet point of the liquid inlet 17 is the geometric center of the plane formed by the intersection of the liquid inlet 17 and the circumferential inner wall. For example, if the cross-section of the liquid inlet 17 is circular and the central axis of the liquid inlet 17 is parallel to the vertical direction, the plane formed by the intersection of the liquid inlet 17 and the circumferential inner wall is a circular surface, then the geometric center (i.e., the liquid inlet point) is the center of the circular surface. The liquid inlet 17 is set through the body 1 and is connected to the outside world. The liquid inlet 17 is connected to the ink cartridge through an inlet pipe. By designing the shape of the liquid cavity 16 and the position of the nozzle 19, the path length of the ink entering from the liquid inlet 17 to each nozzle 19 in the same row is equal, ensuring that the pressure of each nozzle 19 is consistent, ensuring that all nozzles 19 can stably spray droplets, and improving printing quality.

[0035] As Figure 5 shown, preferably, the first inner wall 11 is arc-shaped, and the center line of the first inner wall 11 coincides with or perpendicularly intersects with the central axis of the liquid inlet 17, so that the cross-sectional shape of the liquid cavity 16 is fan-shaped, which is beneficial to ensure that the ink liquid entering from the liquid inlet 17 has equal path lengths to each nozzle 19 in the same row.

[0036] As Figure 1 , 3 shown, in order to ensure that the pressure in the liquid cavity 16 meets the requirements of continuous and stable liquid injection of the nozzles 19, improve the flowability of the ink liquid, and reduce the risk of nozzle 19 blockage, the body 1 is further provided with a liquid outlet 18 communicating with the liquid cavity 16. The liquid outlet 18 penetrates through the body 1 and communicates with the outside, and the liquid outlet 18 communicates with the ink cartridge through a liquid return pipeline. Preferably, in order to make the ink liquid in the entire liquid cavity 16 participate in circulation and facilitate bubble discharge, all nozzles 19 are located between the liquid outlet 18 and the liquid inlet 17 in the direction from the liquid inlet 17 to the first inner wall 11, and the height at which the liquid outlet 18 is connected to the liquid cavity 16 is not lower than the height at which the liquid inlet 17 is connected to the liquid cavity 16. Figure 5 and Figure 7 shown by the dashed line in Figure 6 shown by the dashed line, only to facilitate the illustration of the distance d from the liquid inlet point of the liquid inlet 17 to the nozzle 19, the positional relationship between the nozzle 19, the liquid inlet 17, and the liquid outlet 18 in the direction from the liquid inlet 17 to the first inner wall 11, and the positional relationship between the liquid inlet 17 and the two third inner walls 14, are only one example. In other embodiments, the position of the liquid outlet 18 can be flexibly set according to actual needs, such as the liquid outlet 18 can be arranged at a position between the liquid inlet 17 and the nozzle 19, which is not limited to the above examples. Of course, the body 1 can also not be provided with the liquid outlet 18.

[0037] As Figure 3 , 5As shown, the circumferential inner wall comprises two second inner walls (12, 13) oppositely arranged and connected with the first inner wall 11, two third inner walls 14 oppositely arranged and connected with the first inner wall 11, the two second inner walls (12, 13) and the two third inner walls 14 are arranged around the circumferential edge of the first inner wall 11, the third inner wall 14 is connected with the second inner wall (12, 13), the injection hole 19 is arranged on the second inner wall (12, 13) or the first inner wall 11, the third inner wall 14 is an inclined surface with an angle with the horizontal plane, the third inner wall 14 is straight without bending in the whole length and width, from the liquid inlet 17 to the first inner wall 11, the two third inner walls 14 form an opening with gradually increasing width, and the two third inner walls 14 are symmetrically arranged about the plane passing through the central axis of the liquid inlet 17. Avoiding the path length of the ink flowing to the injection holes 19 located at the opposite edges being different due to the asymmetry and bending of the two third inner walls 14, the path length of the ink flowing from the liquid inlet 17 to each injection hole 19 can be ensured to be equal.

[0038] As shown in Figure 3 , 5 The circumferential inner wall further comprises a fourth inner wall 15 oppositely arranged with the first inner wall 11, the fourth inner wall 15 is connected with the two second inner walls (12, 13) and the two third inner walls 14 away from the first inner wall 11, and the liquid inlet 17 is arranged on the second inner wall (12, 13) or the fourth inner wall 15. In other embodiments, the fourth inner wall 15 can not be arranged, the two second inner walls (12, 13) are directly connected away from the first inner wall 11, or the two third inner walls 14 are directly connected away from the first inner wall 11, or the two second inner walls (12, 13) and the third inner wall 14 away from the first inner wall 11 are directly connected.

[0039] For convenience of description and understanding, it is defined that the two second inner walls (12, 13) are oppositely arranged in the vertical direction, and one of them is the top wall surface 12 and the other is the bottom wall surface 13. The setting positions of the spray holes 19, the liquid inlet 17 and the liquid outlet 18 are various, and are set according to actual needs, such as the following examples. Example one: the spray holes 19 are arranged in an arc shape on the first inner wall 11, the first inner wall 11 is an arc surface, and the liquid inlet 17 can be arranged on the fourth inner wall 15 or the top wall surface 12 or the bottom wall surface 13. When the liquid inlet 17 is arranged on the fourth inner wall 15, the center line of the first inner wall 11 intersects the central axis of the liquid inlet 17 perpendicularly, the liquid inlet 17 can be located at the same height as the spray holes 19, and of course the liquid inlet 17 and the spray holes 19 can be located at different heights. When the liquid inlet 17 is arranged on the top wall surface 12 or the bottom wall surface 13, the center line of the first inner wall 11 coincides with the central axis of the liquid inlet 17. The liquid outlet 18 can be arranged on the top wall surface 12 or the third inner wall 14 or the first inner wall 11, the height at which the liquid outlet 18 is connected to the liquid cavity 16 is greater than the height at which the liquid inlet 17 is connected to the liquid cavity 16, and the liquid outlet 18 is arranged higher than the spray holes 19. Example two: the spray holes 19 are arranged in an arc shape on the bottom wall surface 13, the first inner wall 11 is an arc surface, and the liquid inlet 17 can be arranged on the fourth inner wall 15 or the top wall surface 12 or the bottom wall surface 13. When the liquid inlet 17 is arranged on the fourth inner wall 15, the center line of the first inner wall 11 intersects the central axis of the liquid inlet 17 perpendicularly. When the liquid inlet 17 is arranged on the top wall surface 12 or the bottom wall surface 13, the center line of the first inner wall 11 coincides with the central axis of the liquid inlet 17. The liquid outlet 18 can be arranged on the top wall surface 12 or the third inner wall 14 or the first inner wall 11, the height at which the liquid outlet 18 is connected to the liquid cavity 16 is greater than the height at which the liquid inlet 17 is connected to the liquid cavity 16, and the liquid outlet 18 is arranged higher than the spray holes 19.

[0040] Preferably, in order to reduce the turbulent flow phenomenon of the ink flowing from the liquid inlet 17 into the liquid chamber 16, as shown in Figure 6 , the liquid inlet 17 is arranged on the fourth inner wall 15, and the two third inner walls 14 are respectively tangent to the inner wall edges of the liquid inlet 17. Alternatively, as shown in Figure 7 , the liquid inlet 17 is arranged on the top wall surface 12 or the bottom wall surface 13, and the two third inner walls 14 are respectively tangent to the inner wall edges of the liquid inlet 17.

[0041] <Second embodiment>

[0042] As shown in Figures 8-10As shown, this is the second embodiment of the utility model, the embodiment protects a printing device, the main difference between the second embodiment and the first embodiment is that: in order to improve the printing resolution, the body 1 is provided with two rows or more than two rows of spray holes 19 arranged in the direction gradually away from the liquid inlet 17, the shape of the liquid cavity 16 is different, and the positions of the liquid inlet 17 and the liquid outlet 18 are adaptively adjusted.Specifically, two second inner walls (12, 13) are oppositely arranged along the vertical direction, and one of them is a top wall surface 12, and the other is a bottom wall surface 13, the spray hole 19 is arranged on the bottom wall surface 13, the spray hole 19 has two rows or more than two rows and is arranged in a fan shape, as shown in Figure 8 、 9 As shown, taking four rows of spray holes (I, II, III, IV respectively) as an example for description, Figure 9 The liquid inlet 17 and the liquid outlet 18 cannot be seen by the dotted line, only to show the distance d from the liquid inlet point of the liquid inlet 17 to the spray hole 19, the positional relationship between the spray hole 19, the liquid inlet 17 and the liquid outlet 18 in the direction from the liquid inlet 17 to the first inner wall 11, the distance d from the liquid inlet point of the liquid inlet 17 to the different rows of spray holes 19 is not equal, the distance from the liquid inlet point of the liquid inlet 17 to all the spray holes 19 in the same row is equal, and the vertical distance h between the top wall surface 12 and the bottom wall surface 13 in the direction from the liquid inlet 17 to the first inner wall 11 gradually increases. Because the distance from the liquid inlet point of the liquid inlet 17 to each row of spray holes 19 is not the same, the path length of the ink flowing from the liquid inlet 17 to each row of spray holes 19 is different, the longer the ink flow path, the greater the pressure loss, in order to ensure that the pressure of each row of spray holes 19 is consistent, the liquid level difference formed between the top wall surface 12 and the bottom wall surface 13 in the direction from the liquid inlet 17 to each row of spray holes 19 gradually increases, thereby compensating for the pressure loss generated by the ink flowing to each row of spray holes 19, making the pressure of each row of spray holes 19 consistent, and making the spray holes 19 at different distances from the liquid inlet 17 can stably spray ink, improving the printing quality and the service life of the device. As shown in Figure 10 In the vertical direction, the vertical distance h between the top wall surface 12 and the bottom wall surface 13 corresponding to each spray hole 19 in the same row is the same, to ensure that the pressure compensation of each spray hole 19 in the same row is the same.

[0043] As shown in Figures 8-10 Preferably, all the spray holes 19 are located between the liquid outlet 18 and the liquid inlet 17, the projection point of any one spray hole 19 in the row farthest from the liquid inlet 17 to the top wall surface 12 is the first position E, and the height at which the liquid outlet 18 is connected with the liquid cavity 16 is not lower than the height at which the first position E is located, to ensure that the ink flows from the liquid inlet 17 to form the liquid level difference required for stable spraying of the spray hole 19 in the liquid cavity 16, and to make the ink in the entire liquid cavity 16 participate in circulation.

[0044] In order to realize that the vertical distance between the top wall surface 12 and the bottom wall surface 13 gradually increases in the direction from the liquid inlet 17 to the first inner wall 11, there are many ways to realize it. Example 1: For example Figure 10 As shown, the bottom wall surface 13 can be a horizontal surface perpendicular to the vertical direction, and the top wall surface 12 can be an inclined surface, an arc surface, a broken line surface formed by splicing multiple inclined surfaces, a curved surface formed by splicing multiple arc surfaces, or an irregular surface formed by splicing inclined surfaces and arc surfaces. In this case, preferably, the height of the connection between the liquid outlet 18 and the liquid cavity 16 is not lower than the height of the first position E. Specifically, the liquid outlet 18 is connected to the first position E of the top wall surface 12, or, if the first position E is not the highest point of the top wall surface 12, the liquid outlet 18 can be connected to the highest point of the top wall surface 12, or the liquid outlet 18 can be connected to a position between the first position E of the top wall surface 12 and the highest point of the top wall surface 12, or, the liquid outlet 18 is provided on the third inner wall 14 or the first inner wall 11, and the height of the connection between the liquid outlet 18 and the liquid cavity 16 is not lower than the height of the first position. Example 2: The top wall 12 can be a horizontal surface perpendicular to the vertical direction, and the bottom wall 13 can be an inclined surface, an arc surface, a broken line surface formed by splicing multiple inclined surfaces, a curved surface formed by splicing multiple arc surfaces, or an irregular surface formed by splicing broken lines and arc surfaces. In this case, preferably, the liquid outlet 18 is provided on the top wall 12, the first inner wall 11, or the third inner wall 14. Example 3: Neither the top wall 12 nor the bottom wall 13 is a horizontal surface. The top wall 12 and the bottom wall 13 can be any of inclined surfaces, arc surfaces, broken line surfaces, or irregular surfaces, as long as the vertical distance between the top wall 12 and the bottom wall 13 gradually increases in the direction from the liquid inlet 17 to the first inner wall 11.

[0045] <Third embodiment>

[0046] This is the third embodiment of the present utility model. This embodiment protects a printing device. The main difference between the third embodiment and the first embodiment is that the shape of the first inner wall 11 is different, and accordingly, the structure of the circumferential inner wall is adjusted accordingly. Specifically, the first inner wall 11 is an arc sphere, and the center of the first inner wall 11 is on the central axis of the liquid inlet 17. The spray hole 19 is provided on the first inner wall 11, and the liquid inlet 17 is provided on the side of the circumferential inner wall away from the first inner wall 11, that is, the first inner wall 11 can be provided with only one row of spray holes 19 or at least two rows of spray holes 19, and the distance from each spray hole 19 to the liquid inlet point of the liquid inlet 17 is the same. Ensure that the pressure at each spray hole 19 is consistent. When the first inner wall 11 is provided with two or more rows of spray holes 19, the two adjacent rows of spray holes 19 can be staggered to avoid inconsistent printing colors and improve printing resolution.

[0047] The circumferential inner wall comprises a tapered inner wall connected to the circumferential edge of the first inner wall 11, and the tapered inner wall is symmetrically arranged about a plane passing through the central axis of the liquid inlet 17. The asymmetric circumferential inner wall avoids the path length of the ink flowing to each nozzle 19 being different. The tapered inner wall forms an open-ended liquid cavity, and the shape of the liquid cavity can be conical, circular truncated cone, prismatic or other shapes. Preferably, the liquid inlet 17 is arranged at one end of the tapered inner wall away from the first inner wall 11, and the circumferential edge of the inner wall of the liquid inlet 17 is tangent to the tapered inner wall, reducing the turbulent flow of the ink from the liquid inlet 17 into the liquid cavity 16. The liquid outlet 18 can be arranged on the first inner wall 11 or the circumferential inner wall.

[0048] <Fourth embodiment>

[0049] The fourth embodiment of the utility model provides a kind of printing equipment, and the printing equipment includes the at least one printing device described in the first embodiment or the second embodiment or the third embodiment, and the printing equipment can include one printing device or more than two printing devices, by using the printing device in any one of the first embodiment to the third embodiment, so that the printing equipment can improve printing precision and reliability.

[0050] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0051] Although the embodiments of the utility model have been shown and described above, it cannot be understood as the limitation of claims. The utility model is not limited to the above embodiments, and the specific structure allows changes, and any changes made within the protection scope of the independent claims of the utility model are within the protection scope of the utility model.

Claims

1. A printing device, characterized in that: include: The body comprises a first inner wall and a circumferential inner wall, wherein the first inner wall and the circumferential inner wall form a liquid cavity; the circumferential inner wall is provided with a liquid inlet, and the cross-sectional area of ​​the circumferential inner wall gradually increases in a direction from the liquid inlet to the first inner wall; The body is provided with at least one row of spray holes, which are communicated with the liquid cavity, and the spray holes in the same row are at equal distances from the liquid inlet points of the liquid inlet.

2. A printing device according to claim 1, characterized in that: The first inner wall is an arc-shaped surface, and a center line of the first inner wall coincides with or intersects perpendicularly with a central axis of the liquid inlet.

3. A printing device according to claim 2, characterized in that: The circumferential inner wall includes two second inner walls arranged opposite to each other and connected to the first inner wall, and two third inner walls arranged opposite to each other and connected to the first inner wall. The two second inner walls and the two third inner walls are arranged around the circumferential edge of the first inner wall. The third inner wall is connected to the second inner wall. The spray hole is provided on the second inner wall or the first inner wall. In the direction from the liquid inlet to the first inner wall, an opening with gradually increasing width is formed between the two third inner walls. The two third inner walls are symmetrically arranged about the plane passing through the central axis of the liquid inlet.

4. A printing device according to claim 3, characterized in that: The circumferential inner wall also includes a fourth inner wall arranged opposite to the first inner wall, the fourth inner wall connects the two second inner walls and one end of the two third inner walls away from the first inner wall, and the liquid inlet is arranged on the second inner wall or the fourth inner wall.

5. A printing device according to claim 4, characterized in that: The spray holes are provided on the first inner wall and arranged in an arc shape, and the liquid inlet is provided on the fourth inner wall; And / or, the liquid inlet is provided on the fourth inner wall, and the two third inner walls are respectively tangent to the inner wall edges of the liquid inlet.

6. A printing device according to claim 4, characterized in that: The body is provided with two or more rows of spray holes arranged at intervals in a direction gradually away from the liquid inlet, the two second inner walls are arranged opposite to each other in the vertical direction and one is a top wall surface and the other is a bottom wall surface, the spray holes are provided on the bottom wall surface, and the distances from the spray holes in different rows to the liquid inlet points of the liquid inlet are not equal. In the direction from the liquid inlet to the first inner wall, the vertical distance between the top wall surface and the bottom wall surface gradually increases.

7. A printing device according to claim 6, characterized in that: The body is further provided with a liquid outlet connected to the liquid cavity, all the spray holes are located between the liquid outlet and the liquid inlet, the projection point of any one of the spray holes in the row farthest from the liquid inlet to the top wall surface is the first position, and the height of the connection between the liquid outlet and the liquid cavity is not lower than the height of the first position.

8. A printing device according to claim 1, characterized in that: The body is further provided with a liquid outlet connected to the liquid cavity, all the spray holes are located between the liquid outlet and the liquid inlet, and the height of the connection between the liquid outlet and the liquid cavity is not lower than the height of the connection between the liquid inlet and the liquid cavity.

9. A printing device according to claim 1, characterized in that: The first inner wall is an arc spherical surface, the center of the first inner wall is on the central axis of the liquid inlet, the spray hole is provided on the first inner wall, and the liquid inlet is provided at one end of the circumferential inner wall away from the first inner wall.

10. A printing device according to claim 9, characterized in that: The circumferential inner wall includes a tapered inner wall connected to the circumferential edge of the first inner wall, and the tapered inner wall is symmetrically arranged with respect to a plane passing through the central axis of the liquid inlet; And / or, the first inner wall is provided with two or more rows of spray holes, all the spray holes are equidistant from the liquid inlet point of the liquid inlet, and the spray holes in two adjacent rows are staggered.

11. A printing device, characterized in that: The invention comprises a printing device as described in any one of claims 1 to 10.

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