Resorption fluid printing mechanism

Abstract

The invention relates to the technical field of printing equipment, in particular to a fluid resorption printing mechanism. The fluid resorption printing mechanism comprises a valve body and an elastic flow channel in the valve body, the two ends of the elastic flow channel are connected with a liquid inlet mechanism and a liquid outlet mechanism respectively, a driving mechanism used for driving the elastic flow channel to deform is arranged on one side of the valve body, and the driving mechanism comprises an air inlet mechanism, a piston and a piston diaphragm. The piston diaphragm is connected to the tail end of the air inlet mechanism in a sealed mode, the side, opposite to the tail end of the air inlet mechanism, of the piston diaphragm is connected with the piston, and the piston diaphragm is made of deformable materials. And the piston is in contact with the elastic runner. Compared with the prior art, the fluid resorption printing mechanism has the advantages that the sealing structure is obviously simplified, the use of sealing elements is reduced, in addition, high-precision control can be realized, and the fluid resorption printing mechanism is suitable for precise printing of various fillers and high-viscosity slurry.

Description

Technical Field

[0001] This invention relates to the field of printing equipment technology, and more particularly to a back-suction fluid printing mechanism. Background Technology

[0002] In the field of printing equipment technology, metal pastes such as silver paste, copper paste, and solder paste are commonly used ink materials in precision direct-write printing in the electronics industry. Due to their high filler content and high viscosity, these materials are difficult to control precisely during extrusion. Because of their high viscosity, after the fluid pressure is shut off or the fluid flow is stopped, residual pressure often causes undesirable line shapes such as stringing and tailing, making it difficult to control the shape of the printed line's tail, thus affecting printing accuracy and product quality. Therefore, how to effectively control the shape of the printed line's tail and avoid tailing and stringing has been a long-term research focus in the industry. Typically, a diaphragm backflow valve without dynamic seals can be used as the fluid control valve. This type of valve can withstand high filler content and corrosive adhesives and has backflow shut-off capability, which helps to effectively control the shape of the beginning and end of the printed lines.

[0003] However, existing technologies still have the following problems:

[0004] Firstly, current diaphragm backflow valves are mostly designed for dispensing applications, typically using a valve core to cut off the flow path for shut-off. During the shut-off process, the valve core's sealing surface impacts, squeezes, and rubs against the metal paste, causing tiny metal particles within the paste to be flattened and pressed together, leading to increased particle agglomeration and the formation of foreign objects much larger than the raw material metal particles. These foreign objects easily clog the needle. If a filter is added to intercept them, the continuously generated metal foreign objects will clog the filter, thus shortening the lifespan of the valve body and the needle. Furthermore, existing diaphragm backflow valves generally suffer from excessive flow rates and insufficient backflow accuracy, making it difficult to meet the requirements of precision direct-write printing.

[0005] Secondly, existing back-suction fluid printing equipment has a complex structure, large size, and is difficult to maintain, making it difficult to adapt to the development trend of miniaturized and arrayed printheads. For example, existing technology CN118287698A discloses a flat-plate back-suction diaphragm fluid printing mechanism, also used for precision direct-write printing of metal pastes. This mechanism includes a diaphragm back-suction valve, a feeding mechanism, and a printhead located at the bottom of the diaphragm back-suction valve. The diaphragm back-suction valve includes a valve body, a flat-plate diaphragm horizontally located in the middle of the valve body, and a driving mechanism for driving the flat-plate diaphragm to deform. The driving mechanism is provided with a stroke adjustment mechanism for controlling the deformation of the diaphragm. A feeding chamber is formed between the flat-plate diaphragm and the printhead, and the feeding mechanism is used to supply material to the feeding chamber. During printing, while the external feeding pressure is activated, the drive mechanism drives the flat diaphragm to deform towards the printhead, reducing the volume of the feeding chamber. After printing, the drive mechanism drives the flat diaphragm to recover its deformation away from the printhead, expanding the volume of the feeding chamber and providing a back suction force to cut off the printing material in the feeding chamber. Nevertheless, this mechanism still suffers from problems such as complex structure, large size, and inconvenient maintenance, which is not compatible with the development trend of miniaturization and arraying of printheads.

[0006] In summary, how to provide a back-suction fluid printing mechanism that balances structural simplicity, high precision, and suitability for precision printing is a pressing technical problem that needs to be solved. Summary of the Invention

[0007] The main objective of this invention is to provide a back-suction fluid printing mechanism to solve the problem that existing technologies cannot simultaneously achieve structural simplicity, high precision, and applicability to precision printing.

[0008] This invention provides a back-suction fluid printing mechanism, comprising:

[0009] The valve body and the elastic flow channel inside the valve body are provided with an inlet mechanism and an outlet mechanism respectively connected to the two ends of the elastic flow channel. A drive mechanism for driving the elastic flow channel to deform is provided on one side of the valve body.

[0010] Furthermore, the drive mechanism includes an intake mechanism, a piston, and a piston diaphragm. The piston diaphragm is sealed to the tail end of the intake mechanism, and the side of the piston diaphragm facing away from the tail end of the intake mechanism is connected to the piston. The piston diaphragm is made of a deformable material. The piston is in contact with the elastic flow channel.

[0011] Furthermore, the air intake mechanism includes an air intake connector and an air passage connected to the air intake connector. The air intake connector can be connected to an external air supply device. The external air supply device uses air pressure to deliver external gas from the air intake connector to the air passage. The end of the air passage is sealed with the piston diaphragm. Under the action of external gas, the piston diaphragm will deform, thereby pushing the piston to move towards the elastic flow channel.

[0012] Furthermore, the drive mechanism also includes a first housing and a second housing, the first housing, the second housing and the valve body being connected to each other in sequence, and the piston diaphragm being pressed between the first housing and the second housing.

[0013] Furthermore, the air intake mechanism is fixed to the first housing, the air passage is located inside the first housing, and the second housing has a groove structure for mounting the piston, which can move within the groove.

[0014] Furthermore, the first housing is provided with a protruding structure corresponding to the edge of the piston diaphragm for pressing the piston diaphragm.

[0015] Furthermore, the portion of the piston that contacts the elastic channel is provided with a protrusion for squeezing the elastic channel.

[0016] Furthermore, the liquid inlet mechanism includes a liquid storage cavity and a liquid inlet connector, and the liquid outlet mechanism includes a liquid outlet connector and a printing needle. The liquid inlet connector and the liquid outlet connector are respectively connected to both ends of the elastic flow channel.

[0017] Furthermore, the cavity volume of the airway is much smaller than the cavity volume of the liquid storage cavity.

[0018] Furthermore, a sealing and anti-detachment mechanism is provided at the connection between the liquid inlet connector and the liquid outlet connector and the elastic flow channel. Both connectors are provided with annular barbed protrusions, which are used to expand the inner wall of the elastic flow channel to achieve a tight connection and seal.

[0019] Furthermore, the elastic flow channel is made of a highly elastic material, which can quickly return to its original shape after repeated compression. The elastic flow channel includes an inner layer facing the liquid end and an outer layer away from the liquid end. The inner layer is a fluoropolymer layer, and the outer layer is a highly elastic rubber layer, so as to have both high elasticity and solvent resistance.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) Simplified structure: The elastic flow channel is used to replace the traditional diaphragm, and the piston diaphragm drives the piston to drive the elastic flow channel to deform, replacing the original cylinder piston structure. This design significantly simplifies the sealing structure and reduces the use of seals. It not only compresses the overall volume of the printing mechanism, but also reduces the complexity and frequency of maintenance.

[0022] (2) High-precision control: Since the cavity volume of the air passage is much smaller than that of the liquid storage cavity, the air passage inflation speed is much faster than that of the liquid storage cavity, and the movement response speed of the piston structure is higher than that of the pressure change speed in the liquid storage cavity. When dispensing begins, the piston structure rapidly compresses the elastic channel, causing a rapid increase in ink pressure within the channel. This increases the rate of ink pressure rise at the printing nozzle during the initial printing phase, effectively addressing the issues of slow ink pressure rise and lower-than-target print flow rate during this initial stage. When dispensing stops, the air intake drive mechanism is shut off, allowing gas to be rapidly expelled from the air passage. This quickly releases the piston, causing the elastic channel to return to its original shape and rapidly increase its volume. This creates negative pressure within the elastic channel, releasing residual pressure and achieving backflow prevention for high-viscosity fluids. Furthermore, the protrusion on the piston determines the amount of compression in the elastic channel. Therefore, the deformation of the elastic channel can be controlled by adjusting the size and shape of the protrusion, thus precisely controlling the backflow accuracy. On the other hand, the air intake mechanism and the liquid storage chamber can also use different air paths for control. By controlling the time difference between the switching on and off of the two air paths, different ink switching response effects can be achieved.

[0023] (3) Suitable for precision printing of metal filler inks: The back-suction fluid printing mechanism does not have a fluid cut-off valve core structure and does not have a sealing surface that causes impact and hammering on the fluid material. Therefore, it can avoid the phenomenon of small metal particles in the metal paste being flattened, pressed together, or causing particles to agglomerate in the metal paste. This can effectively reduce the risk of forming metal foreign objects in the fluid material and improve the stability and working time of precision direct writing printing. It is especially suitable for precision direct writing printing of various metal filler inks and high viscosity pastes.

[0024] (4) Convenient maintenance and disassembly: The discharge valve body and the drive mechanism adopt a completely separate design, and the drive mechanism includes a first housing and a second housing. The first housing, the second housing and the valve body are detachably connected to each other in sequence. This modular structure supports the independent disassembly and maintenance of each component, which effectively increases the convenience and safety of mechanism maintenance. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the internal structure of the back-suction fluid printing mechanism;

[0026] Figure 2 This is a side view of the back-suction fluid printing mechanism;

[0027] Figure 3 This is a schematic diagram of the overall structure of the back-suction fluid printing mechanism;

[0028] Figure 4 This is a schematic diagram of the assembly structure of the first housing, the second housing, and the valve body.

[0029] Explanation of reference numerals in the attached drawings: 1-valve body, 2-elastic flow channel, 3-inlet mechanism, 4-piston, 5-piston diaphragm, 6-inlet connector, 7-air passage, 8-first housing, 9-second housing, 10-liquid storage chamber, 11-liquid inlet connector, 12-liquid outlet connector, 13-printing needle. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0031] As described in the background section of this invention, existing diaphragm backflow valves are mostly designed for dispensing applications and often use a valve core to cut off the flow path for shut-off. During the shut-off process, the valve core's sealing surface impacts, squeezes, and rubs against the metal paste, causing tiny metal particles within the paste to be flattened and pressed together, leading to increased particle agglomeration and the formation of foreign matter much larger than the raw material metal particles. Such foreign matter easily causes needle clogging. If a filter is added to intercept it, the continuously generated metal foreign matter will clog the filter, thus shortening the service life of the valve body and needle. In addition, existing diaphragm backflow valves generally suffer from excessively high flow rates and insufficient backflow accuracy, making it difficult to meet the requirements of precision direct-write printing. Furthermore, existing backflow fluid printing equipment has a complex structure, large size, and is difficult to maintain, making it difficult to adapt to the trend of miniaturized and arrayed printheads.

[0032] In view of this, the present invention provides a back-suction fluid printing mechanism, such as... Figure 1-3 As shown, the printing mechanism includes a valve body 1 and an elastic flow channel 2 inside the valve body 1. The two ends of the elastic flow channel 2 are respectively connected to an inlet mechanism and an outlet mechanism. A drive mechanism for deforming the elastic flow channel 2 is provided on one side of the valve body 1. The drive mechanism includes an air inlet mechanism 3, a piston 4, and a piston diaphragm 5. The piston diaphragm 5 is sealed to the tail end of the air inlet mechanism 3, and the side of the piston diaphragm 5 facing away from the tail end of the air inlet mechanism 3 is connected to the piston 4. The piston diaphragm 5 is made of a deformable material. The piston 4 contacts the elastic flow channel 2 and can deform it.

[0033] In some specific embodiments, the air intake mechanism 3 includes an air intake connector 6 and an air passage 7 connected to the air intake connector 6. The air intake connector 6 can be connected to an external air supply device. The external air supply device uses air pressure to deliver external gas from the air intake connector 6 to the air passage 7. The tail end of the air passage 7 is sealed with the piston diaphragm 5. Under the action of external gas, the piston diaphragm 5 will deform, thereby pushing the piston 4 to move towards the side of the elastic flow channel 2.

[0034] like Figure 4 As shown, the drive mechanism also includes a first housing 8 and a second housing 9. The first housing 8, the second housing 9, and the valve body 1 are sequentially and detachably connected to each other (e.g., by screws). The piston diaphragm 5 is pressed between the first housing 8 and the second housing 9. Set screw holes are designed inside the valve body 1 corresponding to the positions of the inlet connector 11 and the outlet connector 12. Set screws are used to fix the inlet connector 11 and the outlet connector 12 to the upper and lower ends of the valve body 1, respectively.

[0035] In some specific embodiments, the air intake mechanism 3 is fixed to the first housing 8, the air passage 7 is disposed inside the first housing 8, and the second housing 9 has a groove structure for mounting the piston 4 on the second housing 9, allowing the piston 4 to move within the groove. The first housing 8 has a protruding structure corresponding to the edge of the piston diaphragm 5 for pressing the piston diaphragm 5. The second housing 9 has a concave structure on the side opposite to the groove structure that matches the shape of the elastic flow channel 2 for accommodating the elastic flow channel assembly 2. Similarly, one side of the valve body 1 also has a concave structure that matches the shape of the elastic flow channel 2. After the second housing 9 and the valve body 1 are fixedly installed, their concave structures match the shape of the elastic flow channel 2. This structure can tighten the elastic flow channel 2, preventing it from expanding and deforming under internal pressure, and also preventing accidental detachment of the connection between the elastic flow channel 2 and the liquid inlet connector 11.

[0036] In some specific embodiments, the liquid inlet mechanism includes a liquid storage chamber 10 and a liquid inlet connector 11, and the liquid outlet mechanism includes a liquid outlet connector 12 and a printing needle 13. The liquid inlet connector 11 and the liquid outlet connector 12 are respectively connected to both ends of the elastic flow channel 2. External ink is connected to the liquid inlet connector 11, flows through the elastic flow channel 2 to the liquid outlet connector 12, and the liquid outlet connector 12 is connected to the printing needle 13, whereby the ink is finally extruded. The ink is loaded in the liquid storage chamber 10, and the ink in the liquid storage chamber 10 is driven downward by external air pressure. The ink may have a certain viscosity and includes, but is not limited to, metal pastes such as silver paste, copper paste, and solder paste, as well as resin materials.

[0037] In some specific embodiments, the cavity volume of the air passage 7 is much smaller than the cavity volume of the liquid storage chamber 10. Therefore, the air pressure rise rate in the air passage 7 is much faster than that in the liquid storage chamber 10. Thus, when the piston 4 begins to move, the air pressure in the liquid storage chamber 10 has not yet reached the target pressure; that is, the ink pressure in the elastic flow channel 2 has not fully reached the target pressure before it is compressed and deformed by the piston 4. Therefore, when the piston 4 moves rapidly and compresses the elastic flow channel 2, the ink pressure in the elastic flow channel 2 will rise rapidly. This characteristic improves the rate of increase in ink pressure at the print head 13 when the ink control air is turned on, effectively improving the problem of print flow rate being lower than the target value in the initial printing stage.

[0038] In some specific embodiments, the connection between the liquid inlet connector 11 and the liquid outlet connector 12 and the elastic flow channel 2 is provided with a sealing and anti-detachment mechanism, for example, a ring-shaped barb connection. Specifically, the liquid inlet connector 11 is used to connect the elastic flow channel 2 and the liquid storage cavity 10. Its upper part is a Luer connector, which cooperates with the Luer connector at the lower end of the liquid storage cavity 10 to form a seal. Its lower part is in the form of a barb, which is inserted into the elastic flow channel 2 to form a seal. The liquid outlet connector 12 is used to connect the elastic flow channel 2 and the printing needle 13. Its upper part is in the form of a barb, which is inserted into the elastic flow channel 2 to form a seal. Its lower part is a Luer connector, which cooperates with the Luer connector of the printing needle 13 to form a seal.

[0039] In some specific embodiments, the portion of the piston 4 that contacts the elastic channel 2 is provided with a protrusion for compressing the elastic channel 2; the back side of the protrusion of the piston 4 is a flat plate structure that contacts the piston diaphragm 5; the length and area of ​​the protrusion of the piston 4 determine the amount of compression of the elastic channel 2, so the deformation of the elastic channel 2 of the back-suction fluid printing mechanism of the present invention can be adjusted by replacing pistons 4 of different sizes and shapes.

[0040] In some specific embodiments, the elastic channel 2 is made of a highly elastic material that can quickly return to its original shape after repeated compression. The elastic channel 2 includes an inner layer facing the liquid end and an outer layer away from the liquid end. The inner layer is a fluoropolymer layer, and the outer layer is a rubber layer. This composite structure combines high elasticity and solvent resistance.

[0041] The working principle of the back-suction fluid printing mechanism of the present invention is described as follows:

[0042] (1) Start-up phase

[0043] When the ink control gas is turned on, gas begins to fill the reservoir 10, causing the gas pressure and ink pressure within the reservoir 10 to rise. Because the reservoir 10 has a certain volume, the pressure rise takes time, and the high viscosity and low fluidity of the ink further reduce the transmission speed of ink pressure to the print head 13. This results in a slow rise in ink pressure at the print head 13 during the initial startup, leading to a lower print flow rate than the target value. To overcome this problem, the external air supply device connected to the air intake mechanism 3 is turned on simultaneously with the ink control gas. Under pressure, gas enters the air passage 7 through the air intake connector 6. The piston diaphragm 5, sealed at the end of the air passage 7, deforms under pressure and squeezes the piston 4. The piston 4 protrudes outward, squeezing the elastic flow channel 2, reducing its internal volume.

[0044] Because the internal volume of the air passage 7 is much smaller than that of the liquid storage chamber 10, the air pressure inside the air passage 7 rises much faster than that of the ink syringe. Therefore, when the piston 4 begins to move, the air pressure inside the liquid storage chamber 10 has not yet reached the target pressure; that is, before the elastic flow channel 2 is compressed and deformed by the piston 4, the ink pressure inside the elastic flow channel 2 has not fully reached the target pressure. Consequently, when the piston 4 moves rapidly to compress the elastic flow channel 2, the ink pressure inside the elastic flow channel 2 rises rapidly. This characteristic increases the rate of ink pressure rise at the print head 13 when the ink control air is activated, effectively improving the problem of print flow rate being lower than the target value in the initial printing stage.

[0045] (2) Shutdown phase

[0046] When the ink control gas is turned off, gas begins to flow out of the reservoir cavity 10, causing the gas pressure and ink pressure within the reservoir cavity 10 to drop. Because the reservoir cavity 10 has a certain volume, the gas pressure within it takes time to decrease. This results in a slow drop in ink pressure at the print head 13 during the initial shutdown phase, preventing the ink from being completely shut off quickly. Residual pressure remains in the ink within the elastic flow channel 2, leading to ink trailing and leakage issues when the ink is shut off.

[0047] To overcome the above problems, the external air supply device connected to the air inlet connector 6 is shut off simultaneously with the ink control air. Gas is rapidly discharged from the air passage 7, the piston diaphragm 5 retracts, the piston 4 becomes free, and the elastic flow channel 2 returns to its original shape under its own elastic force. The volume within the elastic flow channel 2 increases, creating a negative pressure within it. This releases the residual pressure of the fluid within the elastic flow channel 2, achieving back-suction of high-viscosity fluid materials and preventing ink tailing and leakage problems caused by residual ink pressure.

[0048] In summary, when the external air supply device of the air intake mechanism 3 is turned on, gas flows into the air passage 7 through the air intake connector 6. As the air pressure gradually increases, the piston diaphragm 5 is deformed by pressure and protrudes to squeeze the piston 4. At this time, the piston 4 pops outward to squeeze the elastic flow channel 2. After the external air supply device of the air intake mechanism 3 is turned off, the gas in the air passage 7 is discharged, the piston diaphragm 5 retracts, the piston 4 becomes free, and the elastic flow channel 2 returns to its original shape under the action of its own elastic force.

[0049] As can be seen, this invention uses an elastic flow channel to replace the traditional diaphragm, and uses a piston diaphragm to drive the piston, which in turn drives the elastic flow channel to deform, replacing the original cylinder piston structure. This design significantly simplifies the sealing structure, reduces the use of seals, and not only compresses the overall volume of the printing mechanism but also reduces maintenance complexity and frequency. Simultaneously, because the cavity volume of the air channel is much smaller than that of the liquid storage cavity, the air channel's inflation speed is much faster than that of the liquid storage cavity, and the piston structure's motion response speed is higher than the pressure change rate within the liquid storage cavity. At the start of material output, the piston structure rapidly compresses the elastic channel, causing a rapid increase in ink pressure within the channel. This increases the rate of ink pressure rise at the printing nozzle during the initial printing phase, effectively addressing the issues of slow ink pressure rise and lower-than-target print flow rate during this initial stage. After material output stops, the air intake drive mechanism is shut off, allowing gas to be rapidly expelled from the air passage. This quickly releases the piston, causing the elastic channel to return to its original shape and rapidly increase its volume. This creates negative pressure within the elastic channel, releasing residual pressure and achieving backflow prevention for high-viscosity fluid materials. Furthermore, the protrusion on the piston determines the amount of compression in the elastic channel. Therefore, the deformation of the elastic channel can be controlled by adjusting the size and shape of the protrusion, thus precisely controlling the backflow accuracy. On the other hand, the air intake mechanism and the liquid storage chamber can also use different air paths for control. By controlling the time difference between the switching on and off of the two air paths, different ink switching response effects can be achieved. Furthermore, the back-suction fluid printing mechanism does not have a fluid cut-off valve core structure, and there is no impact or hammering on the fluid material from the sealing surface. Therefore, it can avoid the phenomenon of small metal particles in the metal paste being flattened, pressed together, or agglomerated, thereby effectively reducing the risk of forming metal foreign objects in the fluid material, improving the stability and working time of precision direct-write printing, and is suitable for precision direct-write printing of various metal filler inks and high-viscosity pastes. Finally, the discharge valve body and drive mechanism of this invention adopt a completely separate design, and the drive mechanism includes a first housing and a second housing. The first housing, the second housing, and the valve body are sequentially and detachably connected to each other. This modular structure supports independent disassembly and maintenance of each component, effectively increasing the convenience and safety of mechanism maintenance.

[0050] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A fluid recirculation printing mechanism, characterized in that, include: The valve body (1) and the elastic flow channel (2) inside the valve body (1) are respectively connected to the liquid inlet mechanism and the liquid outlet mechanism at both ends of the elastic flow channel (2). A driving mechanism for driving the elastic flow channel (2) to deform is provided on one side of the valve body (1).

2. The back-suction fluid printing mechanism according to claim 1, characterized in that, The drive mechanism includes an intake mechanism (3), a piston (4) and a piston diaphragm (5). The piston diaphragm (5) is sealed to the tail end of the intake mechanism (3). The side of the piston diaphragm (5) facing away from the tail end of the intake mechanism (3) is connected to the piston (4). The piston diaphragm (5) is made of a deformable material. The piston (4) is in contact with the elastic flow channel (2).

3. The back-suction fluid printing mechanism according to claim 2, characterized in that, The air intake mechanism (3) includes an air intake connector (6) and an air passage (7) connected to the air intake connector (6). External gas enters the air passage (7) from the air intake connector (6), and the piston diaphragm (5) is sealed at the tail end of the air passage (7).

4. The back-suction fluid printing mechanism according to claim 3, characterized in that, The drive mechanism also includes a first housing (8) and a second housing (9), the first housing (8), the second housing (9) and the valve body (1) are connected to each other in sequence, and the piston diaphragm (5) is pressed between the first housing (8) and the second housing (9).

5. The back-suction fluid printing mechanism according to claim 4, characterized in that, The air intake mechanism (3) is fixed on the first housing (8), the air passage (7) is located inside the first housing (8), and the second housing (9) is provided with a groove structure for fixing and installing the piston (4).

6. The back-suction fluid printing mechanism according to claim 4, characterized in that, The first housing (8) is provided with a protrusion structure corresponding to the edge of the piston diaphragm (5) for pressing the piston diaphragm (5).

7. The back-suction fluid printing mechanism according to claim 2, characterized in that, The portion of the piston (4) that contacts the elastic channel (2) has a protrusion for squeezing the elastic channel (2).

8. The back-suction fluid printing mechanism according to claim 3, characterized in that, The liquid inlet mechanism includes a liquid storage cavity (10) and a liquid inlet connector (11), and the liquid outlet mechanism includes a liquid outlet connector (12) and a printing needle (13). The liquid inlet connector (11) and the liquid outlet connector (12) are respectively connected to the two ends of the elastic flow channel (2).

9. The back-suction fluid printing mechanism according to claim 8, characterized in that, The inlet connector (11) and outlet connector (12) are provided with a sealing and anti-detachment mechanism at the connection with the elastic flow channel (2).

10. The back-suction fluid printing mechanism according to claim 1, characterized in that, The elastic flow channel (2) includes an inner layer facing the liquid end and an outer layer away from the liquid end, the inner layer being a fluoropolymer layer and the outer layer being a rubber layer.

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