Liquid mixing connector for a nozzle, liquid ejection device, and printing apparatus

Abstract

The utility model relates to a liquid mixing connector for a spray head, a liquid spraying device and printing equipment, a liquid mixing connector for a spray head, a first connecting part is equipped with at the liquid inlet of spray head, including connector body, it is equipped with with the liquid inlet of spray head intercommunication's liquid outlet end, at least two liquid inlet ends and with liquid outlet end and at least two liquid inlet end intercommunication's liquid mixing cavity, liquid outlet end is equipped with with the second connecting part of first connecting part cooperation, first connecting part and second connecting part detachable connection, liquid mixing cavity inside is equipped with the flow channel structure of reinforcing fluid mixing, flow channel structure be configured as the liquid that will respectively from two different liquid inlet end flow in in the process of flowing in flow channel structure is mixed fully. Can realize instant high -efficient liquid mixing, and it is detachable connection with spray head, compact structure, convenient replacement and maintenance, be favorable to the efficiency of improving switching printing other color.

Description

Technical Field

[0001] This utility model relates to the field of printing technology, and in particular to a liquid mixing connector for a printhead, a liquid jetting device, and a printing device. Background Technology

[0002] When printing the desired color using existing printing equipment, a large amount of various base inks of different colors must first be fed into a mixing tank through pipes in proportion. The ink is then mixed in the mixing tank to form an ink that is very close to or consistent with the desired color. The prepared ink is then fed into the printhead through pipes. Although the above method can achieve the desired color, the large amount of various inks need to be mixed evenly in the mixing tank, which requires stirring and takes a long time. When printing other colors, the mixing tank and pipes need to be cleaned, which takes a long time and results in low printing efficiency. Utility Model Content

[0003] This invention addresses the problems existing in the prior art by providing a liquid mixing connector, liquid jetting device, and printing equipment for a printhead. It enables instant and efficient liquid mixing, is detachably connected to the printhead, has a compact structure, is easy to replace and maintain, and helps improve the efficiency of switching to other colors.

[0004] In a first aspect, this utility model provides a mixing connector for a nozzle, wherein a first connecting portion is provided at the inlet of the nozzle, and the mixing connector for the nozzle includes: a connector body, which has an outlet end communicating with the inlet of the nozzle, at least two inlet ends, and a mixing chamber communicating with the outlet end and the at least two inlet ends; the outlet end has a second connecting portion cooperating with the first connecting portion, and the first connecting portion and the second connecting portion are detachably connected; the mixing chamber has a flow channel structure for enhancing fluid mixing, and the flow channel structure is configured to fully mix liquids flowing in from the two different inlet ends during the flow within the flow channel structure.

[0005] In one embodiment, the first connecting part and the second connecting part are connected by a plug-in connection or by mechanical fastening.

[0006] In one embodiment, the second connecting part is a threaded part or an elastic snap-fit ​​part.

[0007] In one embodiment, the liquid inlet includes a straight pipe section communicating with the mixing chamber, and the central axes of the straight pipe sections of the plurality of liquid inlets have an included angle; Alternatively, multiple inlet terminals may be radially distributed around the mixing chamber.

[0008] In one embodiment, the flow channel structure includes a bend and meandering flow channel, wherein the inflow end and the outflow end of the bend and meandering flow channel are respectively connected to each of the liquid inlet end and the liquid outlet end.

[0009] In one implementation, the meandering flow channel includes a serpentine flow channel, a U-shaped flow channel, or a spiral flow channel; Alternatively, the meandering flow channel may include a mixed flow channel in which branching flow channels and converging flow channels are alternately connected.

[0010] In one embodiment, the flow channel structure includes a static mixing component configured to generate shearing, splitting, confluence, or turbulence as the liquid flows through it, thereby promoting liquid mixing.

[0011] In one embodiment, the mixing chamber is provided with a long branch channel and a short branch channel corresponding to and connected to each of the liquid inlet ends, and a confluence channel connected to the short branch channel connected to each of the liquid inlet ends. The long branch channels and the confluence channel are arranged adjacent to each other, and two or more partitions are provided between the confluence channel and each of the long branch channels, spaced apart along the extension direction of the confluence channel.

[0012] In one embodiment, the connector body is provided with a heating device; and / or, the connector body is provided with a filter near the liquid outlet end.

[0013] Secondly, this utility model provides a liquid injection device, including: a mixing connector for a nozzle as described above, and a nozzle; the nozzle has a first connecting part at its inlet that is detachably connected to the second connecting part, and the first connecting part is connected to the second connecting part so that the outlet end communicates with the inlet.

[0014] In one embodiment, the first connecting part is an internal thread formed on the inner wall of the liquid inlet, and the second connecting part is an external thread formed on the liquid outlet and threadedly engaged with the internal thread; or, the first connecting part is a groove formed on the inner wall of the liquid inlet, and the second connecting part is an elastic snap-fit ​​part formed on the outer wall of the liquid outlet, wherein the elastic snap-fit ​​part engages with the groove.

[0015] Thirdly, this utility model provides a printing device, comprising: at least one liquid jetting device as described above; two or more liquid storage boxes configured to store two or more different types of liquids respectively, wherein the liquid storage boxes are connected to the corresponding liquid inlet end through a liquid delivery pipe, and the liquid delivery pipe is provided with a delivery pump or the liquid storage box is provided with a pressure interface.

[0016] By adopting the above structure, this utility model has the following advantages compared with the prior art: The mixing connector for the printhead includes a connector body, which has an outlet end communicating with the printhead's inlet, at least two inlet ends, and a mixing chamber communicating with the outlet end and the at least two inlet ends. The mixing chamber has a flow channel structure to enhance fluid mixing. The outlet end has a second connecting part that is detachably connected to the first connecting part. The mixing connector provides instant and efficient mixing. Its detachable connection to the printhead facilitates installation, disassembly, and maintenance, making it highly practical and improving the efficiency of switching to other colors. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the first structure of the mixing connector for the nozzle according to Embodiment 1 of this utility model; Figure 2 for Figure 1 Internal structure diagram; Figure 3 This is a schematic diagram of the second structure of the mixing connector for the nozzle in Embodiment 1 of this utility model; Figure 4 for Figure 3 Internal structure diagram; Figure 5 This is a schematic diagram of the first structure of the liquid injection device according to Embodiment 2 of this utility model; Figure 6 This is a schematic diagram of the second structure of the liquid injection device according to Embodiment 2 of this utility model; Figure 7 for Figure 6 An enlarged schematic diagram of the cross-sectional view at point A; Figure 8 This is a schematic diagram of the printing device according to Embodiment 3 of this utility model.

[0018] In the attached drawings: 100 for mixing connector; 1 for connector body; 11 for inlet; 12 for outlet; 13 for mixing chamber; 131 for bend and meandering flow channel; 1311 for short branch flow channel; 1312 for long branch flow channel; 1313 for mixing flow channel; 132 for flow divider; 133 for flow turbulence device; 134 for separator; 1341 for flow guide; 135 for baffle plate; 14 for second connection; 17 for filter; 18 for heating device; 200 for nozzle; 201 for inlet; 202 for first connection; 203 for inlet pipe; 300 for storage box; and 301 for infusion pipeline. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0021] Example 1 like Figure 1-4 As shown, this application embodiment provides a mixing connector 100 for a nozzle 200, referring to... Figure 7 The nozzle 200 has a first connecting part 202 at the liquid inlet 201, including: a connector body 1, which has an outlet end 12 communicating with the liquid inlet 201 of the nozzle 200, at least two inlet ends 11, and a mixing chamber 13 communicating with the outlet end 12 and the at least two inlet ends 11. The outlet end 12 has a second connecting part 14 that cooperates with the first connecting part 202. The first connecting part 202 and the second connecting part 14 are detachably connected. The mixing chamber 13 has a flow channel structure that enhances fluid mixing. The flow channel structure is configured to fully mix the liquids flowing in from the two different inlet ends 11 during the flow process within the flow channel structure.

[0022] Multiple liquids with preset volume or mass ratios are fed into the mixing connector 100 and mixed to form the desired color printing liquid. The mixing connector 100 is a small mixing device that is easy to install and disassemble. It can achieve instant and efficient mixing of small flow rates or volumes, and the mixing is uniform, thus playing the role of online real-time mixing. The liquid outlet 12 of the mixing connector 100 is provided with a second connecting part 14 that cooperates with the first connecting part 202 of the printhead 200. The uniformly mixed printing liquid of the desired color inside the mixing connector 100 enters the interior of the printhead 200 through the liquid outlet 12. Furthermore, the first connecting part 202 and the second connecting part 14 are detachably connected, which is convenient for installation, disassembly and maintenance. It is highly practical. When it is necessary to switch to printing other colors, the mixing connector 100 can be removed from the printhead 200 for cleaning and a new mixing connector 100 can be replaced. This eliminates the need for traditional inkjet printing systems to stop the machine to clean the mixing tank and pipeline when switching to different colors, which helps to improve the efficiency and convenience of switching printing colors.

[0023] Specifically, the detachable connection can be a plug-in connection or a mechanically fixed connection. To achieve a plug-in connection or mechanical fastening connection between the first connection part 202 and the second connection part 14, and to facilitate the installation and disassembly of the mixing connector 100, preferably, the second connection part 14 is a threaded part or an elastic snap-fit ​​part. Specifically, the liquid outlet end 12 is a tubular structure, and the second connection part 14 is a threaded part provided on the inner or outer wall of the tubular structure. Correspondingly, the first connection part 202 can be a threaded connection part that mates with the threaded part. Alternatively, the second connection part 14 can be an elastic snap-fit ​​part provided on the outer wall or end of the tubular structure. Specifically, the elastic snap-fit ​​part can be an elastic claw, and correspondingly, the first connection part 202 can be a slot that engages with the elastic claw. In addition to the above, the first connecting part 202 and the second connecting part 14 can also be connected by a sleeve-type quick connector consisting of clamps, rubber sealing rings, fasteners, etc., or by a pipe connector that achieves sealing and pressure bearing function using a combination of stainless steel and rubber components, or by a flange connection or other methods to achieve mechanical fastening connection. In addition to the above, other structures or methods that can achieve plug-in or mechanical fastening connection are also possible, and no specific restrictions are imposed.

[0024] Furthermore, to improve the sealing performance at the connection between the liquid outlet 12 and the liquid inlet 201, a sealing structure is provided between the first connecting part 202 and the second connecting part 14. Specifically, the sealing structure can be a sealing ring.

[0025] Furthermore, to improve the liquid mixing effect within the mixing chamber 13, improvements can be made in aspects such as the structural design and flow control of the mixing chamber 13. In some examples, the flow channel design inside the mixing chamber 13 is optimized. The flow channel structure includes a tortuous flow channel 131, the inlet and outlet ends of which are respectively connected to the inlet end 11 and the outlet end 12. The tortuous flow channel 131 can extend the liquid mixing path, increase the contact area and opportunities between liquids, disrupt the laminar boundary to generate local turbulence, and significantly improve mixing efficiency and mixing uniformity. Specifically, the cavity wall of the mixing chamber 13 can be a curved structure to form the tortuous flow channel 131. To enhance the disturbance effect, further improvements can be made to the cavity wall, such as corrugated structures or protrusions, or, for example... Figure 2 As shown, the tortuous flow channel 131 can be formed by the cavity wall and a plurality of baffles 135 arranged on the cavity wall at intervals along the axial direction. The through holes or flow channels of adjacent baffles 135 are staggered or their axial projections overlap, thereby making the flow channel tortuous. Alternatively, the tortuous flow channel 131 can be formed by the cavity wall and a plurality of baffles arranged on the cavity wall in a preset arrangement. The preset arrangement can be an axial staggered arrangement, an axial spiral arrangement, a honeycomb arrangement, etc. The above arrangement can enhance the shearing and diffusion of the liquid. The liquid is continuously divided, interlaced and recombined by the baffles, which significantly improves the uniformity of liquid mixing.

[0026] Specifically, the meandering flow channel 131 includes a serpentine, U-shaped, or spiral flow channel. When the liquid flows through the turning points, turbulence is created, changing the flow direction and enhancing mixing. Alternatively, the meandering flow channel 131 includes a mixing channel with alternating branching and converging flow channels. When the liquid flows through the intersections, it is forced to branch and then re-converge, forming a complex flow path, which is beneficial for forming a uniformly concentrated printing fluid. For example, the meandering flow channel 131 can have a honeycomb or tree-like structure, etc.

[0027] Furthermore, the flow channel structure includes static mixing components, which are configured to generate shearing, diversion, confluence, or turbulence when the liquid flows through them, thereby promoting liquid mixing. The static mixing components include flow disruptors (including the aforementioned baffles), flow guides, separators (including the aforementioned baffle 135), flow dividers, flow deflectors, porous media, three-dimensional mesh structures, etc. Multiple static mixing components can be present and arranged in a specific pattern to form a tortuous and meandering flow channel that ensures uniform mixing of the liquid after it flows through. The arrangement can be diverse, including regular arrangements with certain patterns such as axial staggered arrangements, axial spiral arrangements, tree-like arrangements, and honeycomb arrangements, as well as irregular arrangements.

[0028] The following is a specific example of forming a tortuous flow channel 131, such as Figure 4As shown, the mixing chamber 13 is provided with a long branch channel 1312 and a short branch channel 1311 corresponding to and communicating with each of the liquid inlet ends 11, and a confluence channel 1313 communicating with the short branch channels 1311 communicating with each of the liquid inlet ends 11. The long branch channels 1312 and the confluence channel 1313 are arranged adjacent to each other, and two or more partitions 134 are provided between the confluence channel 1313 and each of the long branch channels 1312, which are spaced apart along the extension direction of the confluence channel 1313. The long branch channels 1312 and the short branch channels 1311 are separated by a flow divider 132. Furthermore, multiple flow-disrupting elements 133 are spaced apart along the extension direction of the confluence channel 1313, with adjacent flow-disrupting elements 133 arranged alternately. Each liquid is first split into two parts when entering the mixing connector 100, flowing into the long branch channel 1312 and the short branch channel 1311 respectively. All the liquids in the short branch channels 1311 are initially mixed at the inlet end of the confluence channel 1313. When flowing along the extension direction of the confluence channel 1313, they collide and split through the flow-disrupting elements 133, and the gaps between the separators 134 allow for sufficient exchange of liquids between the long branch channels 1312 and the confluence channel 1313, further enhancing the mixing. The mixing chamber 13, including its walls, flow divider 132, flow disruptor 133, and separator 134, forms a tortuous flow channel 131. This channel repeatedly changes the liquid flow direction within the mixing chamber 13, creating strong shear forces and complex flow paths. This facilitates deep mixing of different liquids, ensuring reliable and uniform mixing. Preferably, the flow disruptor 133 is an arc-shaped plate, and the separator 134 has an arc-shaped guide portion 1341. This reduces resistance when the liquid contacts the flow disruptor 133 and the separator 134, ensuring smooth liquid flow.

[0029] In some examples, the liquid mixing degree is improved by designing the liquid inlet direction. Specifically, the liquid inlet 11 includes a straight pipe section communicating with the mixing chamber 13. The central axes of the straight pipe sections of the plurality of liquid inlet ends 11 have an angle, so that the liquid from the liquid inlet end 11 enters the mixing chamber 13 obliquely or tangentially at a certain shear rate, which is conducive to the diffusion of the liquid and enhances the mixing probability. Alternatively, the plurality of liquid inlet ends 11 are radially distributed around the mixing chamber 13, which is conducive to the initial mixing of different liquids in the initial stage of entering the mixing chamber.

[0030] Furthermore, such as Figure 4 As shown, the connector body 1 is provided with a filter 17 near the liquid outlet 12. The filter 17 can filter the liquid to prevent impurities from entering the printhead 200, which is beneficial to improving the printing performance of the liquid. The filter 17 may include a filter screen.

[0031] Furthermore, such as Figure 3As shown, the connector body 1 is equipped with a heating device 18. By controlling the heating device 18 to heat the liquid, the liquid is kept at a suitable temperature for spraying and flow, which helps to improve spraying accuracy and reliability. The specific structure of the heating device 18 can refer to existing pipeline heating structures and is not limited to any specific design. For example, the heating device 18 includes heating elements disposed on the outer wall of the connector body 1. The heating elements are electrically connected to a power source. The internal temperature of the connector body is maintained by controlling the temperature of the heating elements. Specifically, PID closed-loop control or frequency conversion heating can be used to achieve precise dynamic constant temperature control.

[0032] Example 2 Based on the above-mentioned mixing connector 100 for nozzle 200, such as Figure 5-7 As shown in the illustration, this application provides a liquid jetting device, including: a mixing connector 100 for the nozzle 200 as described in Embodiment 1, and a nozzle 200; the nozzle 200 has a first connecting portion 202 at its liquid inlet 201, which is detachably connected to the second connecting portion 14, and the first connecting portion 202 is connected to the second connecting portion 14 so that the liquid outlet 12 communicates with the liquid inlet 201. The nozzle 200 cooperates with the mixing connector 100 to jet different colored mixed liquids onto the medium to print different colors.

[0033] To achieve a plug-in or mechanical fastening connection between the first connecting part 202 and the second connecting part 14, in some specific examples, the nozzle 200 is provided with an inlet pipe forming an inlet 201, a portion of which extends outside the nozzle 200. The first connecting part 202 is an internal thread formed on the inner wall of the inlet 201, and the second connecting part 14 is an external thread formed on the outlet end 12 and engaging with the internal thread. Alternatively, the first connecting part 202 is a groove formed on the inner wall of the inlet 201, and the second connecting part 14 is an elastic snap-fit ​​part formed on the outer wall of the outlet end 12, the elastic snap-fit ​​part engaging with the groove. In addition to the above, for ease of connection, the inlet pipe and the tubular structure forming the outlet end 12 are connected via a clamp connector, an elastic sleeve, a pipe connector, or a flange.

[0034] Example 3 Based on the above-mentioned mixing connector 100 for nozzle 200 and liquid injection device, such as Figure 8As shown, this application provides a printing device, including: at least one liquid jetting device as described in Embodiment 2; two or more liquid storage tanks 300 configured to store two or more different types of liquids respectively, wherein each liquid storage tank 300 is connected to a corresponding liquid inlet 11 via a liquid delivery pipe 301, and the liquid delivery pipe 301 is equipped with a delivery pump or the liquid storage tank 300 is equipped with a pneumatic interface. To facilitate the connection between the liquid storage tank 300 and the mixing connector 100 via the liquid delivery pipe 301, the liquid inlet 11 is equipped with a quick-connect connector for connection to the liquid delivery pipe 301. The printhead 200 is configured as a continuous inkjet printhead or an on-demand inkjet printhead. To control the volume or mass of the corresponding liquid injected into the mixing connector 100, as an example, the infusion pipeline 301 is equipped with a delivery pump (not shown). By controlling the speed of the delivery pump, the volume or mass of the corresponding liquid injected into the mixing connector 100 is controlled. Simultaneously, the liquid in the reservoir 300 is delivered to the mixing connector 100 under the pressure of the delivery pump. Inside the mixing connector 100, the liquid is uniformly mixed to form the printing liquid of the desired color. The printing liquid is then delivered to the printhead 200 under positive pressure. This closed-loop control allows for precise adjustment of the liquid entering the mixing connector 100 from the reservoir 300. The volume or mass of the liquid is controlled by the infusion pipeline 301, which is equipped with a finely adjustable proportional regulating valve and a flow sensor. Based on this, when the printhead 200 is configured as an on-demand inkjet printhead, the printhead 200 includes a nozzle, an inlet channel connected to the nozzle, and a return channel. To prevent the printing liquid from flowing out when the printhead 200 does not need to eject droplets, the return channel is opened to ensure that the flow resistance of the return channel is significantly less than the flow resistance at the nozzle, thus creating a negative pressure at the nozzle. Alternatively, the return channel can be connected to a negative pressure source, and a negative pressure can be created by controlling the rotation speed of the negative pressure source. The pressure difference between the inlet channel and the return channel is controlled to ensure a negative pressure at the nozzle. As another example, the liquid reservoir 300 is equipped with a pneumatic interface, which can be connected to an external positive or negative pressure source. The positive pressure source can be an air pump or compressed air pipeline, used to apply controllable positive pressure to the inside of the liquid reservoir 300 to discharge the liquid to the mixing connector 100. When the pneumatic interface is connected to the positive pressure source and the printhead 200 is configured as an on-demand inkjet printhead, in order to prevent the printhead 200 from leaking out when it does not need to eject droplets, the return channel is opened to ensure that the flow resistance of the return channel is significantly less than the flow resistance at the nozzle, thus forming a negative pressure at the nozzle. Alternatively, the return channel can be connected to a negative pressure source, and a negative pressure can be formed by controlling the rotation speed of the negative pressure source. The pressure difference between the liquid inlet channel and the return channel can be controlled to ensure a negative pressure at the nozzle.The negative pressure source can be a vacuum pump or a negative pressure generator, used to provide negative pressure to the liquid reservoir 300, drawing the liquid from the liquid reservoir 300 into the mixing connector 100. At the same time, the negative pressure creates a certain suction force on the printing liquid in the printhead 200, preventing the printing liquid in the printhead 200 from flowing out. The air pressure interface connected to the negative pressure source is suitable for the case where the printhead 200 is configured as an on-demand inkjet printhead. In order to achieve closed-loop control to accurately adjust the volume or mass of the liquid entering the mixing connector 100 from the liquid reservoir 300, the pipe connecting the liquid reservoir 300 to the positive pressure source or negative pressure source is also equipped with a fine-tunable proportional regulating valve and a pressure sensor.

[0035] Although embodiments of the present invention have been shown and described above, they should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All changes made within the scope of the independent claims of the present invention are within the scope of protection of the present invention.

Claims

1. A mixing connector for a nozzle, wherein a first connecting portion is provided at the liquid inlet of the nozzle, characterized in that, include: The connector body is provided with an outlet end communicating with the inlet of the nozzle, at least two inlet ends, and a mixing chamber communicating with the outlet end and the at least two inlet ends. The liquid outlet end is provided with a second connecting part that cooperates with the first connecting part, and the first connecting part and the second connecting part are detachably connected; The mixing chamber is provided with a flow channel structure to enhance fluid mixing. The flow channel structure is configured to fully mix the liquids flowing in from the two different inlet ends as they flow within the flow channel structure.

2. The mixing connector for a nozzle as described in claim 1, characterized in that, The first connecting part and the second connecting part are connected by a plug-in connection or by mechanical fastening.

3. The mixing connector for a nozzle as described in claim 2, characterized in that, The second connecting part is a threaded part or an elastic snap-fit ​​part.

4. The mixing connector for a nozzle as described in claim 1, characterized in that, The liquid inlet includes a straight pipe section communicating with the mixing chamber, and the central axes of the straight pipe sections of the plurality of liquid inlets have an included angle; Alternatively, multiple inlet terminals may be radially distributed around the mixing chamber.

5. The mixing connector for a nozzle as described in claim 1, characterized in that, The flow channel structure includes a tortuous flow channel, wherein the inflow end and the outflow end of the tortuous flow channel are respectively connected to the liquid inlet end and the liquid outlet end.

6. The mixing connector for a nozzle as described in claim 5, characterized in that, The meandering flow channel includes a serpentine flow channel, a U-shaped flow channel, or a spiral flow channel; Alternatively, the meandering flow channel may include a mixed flow channel in which branching flow channels and converging flow channels are alternately connected.

7. The mixing connector for a nozzle as described in claim 1, characterized in that, The flow channel structure includes a static mixing component configured to generate shearing, splitting, confluence, or turbulence as the liquid flows through it, thereby promoting liquid mixing.

8. The mixing connector for a nozzle as described in claim 1, characterized in that, The mixing chamber is provided with a long branch channel and a short branch channel corresponding to and connected to each of the liquid inlet ends, and a confluence channel connected to the short branch channel connected to each of the liquid inlet ends. The long branch channels and the confluence channel are arranged adjacent to each other, and there are two or more partitions between the confluence channel and each of the long branch channels, which are spaced apart along the extension direction of the confluence channel.

9. The mixing connector for a nozzle as described in claim 1, characterized in that, The connector body is equipped with a heating device; And / or, the connector body is provided with a filter near the liquid outlet end.

10. A liquid injection device, characterized in that, include: The mixing connector and nozzle for a spray head as described in any one of claims 1-9; the spray head has a first connecting part at the inlet that is detachably connected to the second connecting part, the first connecting part being connected to the second connecting part so that the outlet end communicates with the inlet.

11. The liquid injection device as claimed in claim 10, characterized in that, The first connecting part is an internal thread formed on the inner wall of the liquid inlet, and the second connecting part is an external thread formed on the liquid outlet and threadedly engaged with the internal thread. Alternatively, the first connecting part is a groove formed on the inner wall of the liquid inlet, and the second connecting part is an elastic snap-fit ​​part formed on the outer wall of the liquid outlet, wherein the elastic snap-fit ​​part engages with the groove.

12. A printing device, characterized in that, include: At least one liquid injection device as described in claim 10 or 11; Two or more liquid storage boxes are configured to store two or more different types of liquids respectively. The liquid storage boxes are connected to the corresponding liquid inlet end through a liquid delivery pipe. The liquid delivery pipe is equipped with a delivery pump or the liquid storage box is equipped with a pressure interface.

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