A circulating bubble-removing ink supply system and method for inkjet printing

Abstract

The application discloses a circulating bubble-removing ink supply system and method special for ink-jet printing, and relates to the technical field of ink-jet printing. The ink supply system comprises a nozzle assembly, one end of the nozzle assembly is connected with a liquid inlet pipeline, the other end of the liquid inlet pipeline is connected with a buffer bottle; a liquid outlet pipeline is further connected to the buffer bottle, the other end of the liquid outlet pipeline is connected with a liquid storage bottle used for storing ink; the other side of the nozzle assembly is further connected with a liquid return pipeline, the other end of the liquid return pipeline is connected with the buffer bottle, the nozzle assembly comprises a nozzle, the nozzle is connected with the liquid inlet pipeline and the nozzle assembly through an ink-jet channel, and an electric control valve is arranged between the ink-jet channel and the liquid inlet pipeline and the nozzle assembly; the application can completely remove the tiny bubbles, avoid the phenomena of ink breakage, flying ink or ink drop deviation in the initial stage of ink-jet printing, and effectively improve the printing quality and consistency.

Description

Technical Field

[0001] This invention relates to the field of inkjet printing technology, and in particular to a circulating de-bubbling ink supply system and method specifically for inkjet printing. Background Technology

[0002] Inkjet printing is a non-contact digital printing technology that precisely sprays tiny ink droplets onto the surface of substrates such as paper, plastic, and fabric to create text, images, or patterns. Its core principle is based on computer-controlled ink jetting paths, achieving high-precision and high-efficiency printing results.

[0003] Currently, industrial printing widely employs gravity or negative pressure ink supply methods. These methods utilize liquid level differences or vacuum sources to stably deliver ink to the printhead, enabling continuous inkjet printing. Before printing, air bubbles need to be removed. During printing, as ink is gradually consumed, the level in the buffer bottle drops, requiring further ink supply.

[0004] In practical applications, existing ink supply systems for inkjet printing have the following drawbacks:

[0005] 1. Incomplete degassing before printing: Traditional printing systems mostly rely on manual operation or simple air pressure flushing to degas, which cannot form an effective circulation flow path. Especially for long-distance, complex and tortuous pipeline systems, tiny air bubbles are difficult to completely remove and often remain in the buffer bottle or the front of the printhead channel. In the initial stage of printing, ink interruption, ink splatter, or ink droplet deviation are likely to occur, which seriously affects print quality and consistency.

[0006] 2. Pressure fluctuations during printing: In negative pressure ink supply systems, as ink is gradually consumed, the liquid level in the reservoir continuously decreases, and changes in the liquid column height cause negative pressure fluctuations in the system. Because the printhead is highly sensitive to ink supply pressure, even small pressure changes can cause ink droplet volume drift and image distortion, especially in high-precision coating or printing of precision functional materials, which can easily lead to process defects. Summary of the Invention

[0007] This invention provides a circulating ink supply and de-bubbling system and method for inkjet printing, which can solve the following problems existing in the prior art:

[0008] 1) Traditional printing systems mostly rely on manual operation or simple air pressure flushing for de-bubbling, which cannot form an effective circulation flow path. Especially for long-distance, complex and tortuous pipeline systems, tiny air bubbles are difficult to completely remove and often remain in the buffer bottle or the front end of the printhead channel. In the initial stage of printing, phenomena such as ink interruption, ink splatter, or ink droplet deviation are likely to occur. 2) In negative pressure ink supply systems, as ink is gradually consumed, the liquid level in the reservoir bottle continues to drop. Changes in the liquid column height cause fluctuations in the negative pressure of the system. Since the printhead is highly sensitive to ink supply pressure, even small pressure changes can cause ink droplet volume drift and image distortion. Especially in high-precision coating or precision functional material printing scenarios, it is more likely to lead to process defects.

[0009] A circulating de-bubbling ink supply system for inkjet printing includes a printhead assembly, one end of which is connected to an inlet pipe, and the other end of which is connected to a buffer bottle.

[0010] The buffer bottle is also connected to an infusion line, the other end of which is connected to a storage bottle for storing ink.

[0011] The other side of the printhead assembly is also connected to a return liquid line, and the other end of the return liquid line is connected to a buffer bottle. The printhead assembly includes a nozzle, which is connected to the inlet liquid line and the printhead assembly through an inkjet channel. An electronically controlled valve is provided between the inkjet channel, the inlet liquid line, and the printhead assembly.

[0012] The return pipeline is equipped with a return module, which is used to circulate the ink delivered by the inlet pipeline to the buffer bottle through the return pipeline.

[0013] Preferably, the nozzle assembly has a liquid inlet end on one side, one end of which is connected to the liquid inlet channel in the nozzle assembly and the other end is connected to the liquid inlet pipe. The nozzle assembly also has a liquid return end on the other side, one end of which is connected to the liquid return channel in the nozzle assembly.

[0014] The nozzle is connected to the liquid inlet channel and the liquid return channel, and the electronically controlled valve is installed in the inkjet channel.

[0015] Preferably, the end of the return line away from the nozzle assembly is connected to the infusion line, and the connection end of the two is located on the side of the infusion line closer to the buffer bottle.

[0016] The infusion pipeline has an inverted U-shaped structure.

[0017] Preferably, the return fluid module includes an infusion pump installed on the infusion pipeline, with the infusion pump positioned between the end of the return fluid pipeline and the buffer bottle.

[0018] Preferably, the infusion line is equipped with a first solenoid valve, which is located between the end of the return line and the storage bottle.

[0019] The inlet pipeline is equipped with a second solenoid valve, and the return pipeline is equipped with a third solenoid valve.

[0020] Preferably, the buffer bottle is provided with a first air pressure branch pipe, the end of the first air pressure branch pipe away from the buffer bottle is connected to the main air pressure pipe, and the end of the main air pressure pipe is connected to the air source assembly.

[0021] Preferably, the liquid storage bottle is also connected to a second pneumatic branch pipe, and the end of the second pneumatic branch pipe away from the liquid storage bottle is connected to the main pneumatic pipe.

[0022] Preferably, the gas source assembly includes a gas source switching valve installed at the end of the gas pressure main pipe, and the other end of the gas source switching valve is connected to a positive pressure gas source.

[0023] A fourth solenoid valve is also provided between the main air pressure pipes.

[0024] Preferably, the gas source assembly further includes a negative pressure gas source connected to the gas source switching valve.

[0025] A circulating ink supply method for inkjet printing, applied to the aforementioned circulating ink supply system for inkjet printing, includes the following steps:

[0026] Pre-filling with ink: The air source switching valve is switched to connect to the positive pressure air source, the fourth and second solenoid valves are opened, and the first and third solenoid valves are closed; the positive pressure air source pushes the ink through the buffer bottle into the printhead assembly and pipeline to complete the pre-filling;

[0027] Slow-pressure circulation defoaming: Close the fourth solenoid valve, open the first, second, and third solenoid valves, start the infusion pump to form a closed-loop circulation, and the ink flows at a low speed to effectively remove residual micro-bubbles in the system.

[0028] Press ink again with positive pressure: Keep the air source switching valve under positive pressure, open the fourth and second solenoid valves, and close the first and third solenoid valves to further remove trace amounts of residual air bubbles and ensure that air bubbles are completely removed from the system.

[0029] Replenishment: Open the first solenoid valve, and close the second, third, and fourth solenoid valves. The ink is replenished from the storage bottle to the buffer bottle to ensure the liquid level.

[0030] Switching to negative pressure to prepare for printing: Switch the air source switching valve to connect to the negative pressure air source, open the fourth solenoid valve, the second solenoid valve, and the third solenoid valve, and close the first solenoid valve. The system establishes a stable negative pressure and enters the printing operation state.

[0031] This invention provides a circulating ink supply and de-bubbling system and method for inkjet printing, which has the following beneficial effects:

[0032] 1) Before inkjet printing, in order to remove residual air bubbles in the various pipelines and the printhead assembly, the electronically controlled valve of the present invention is in a closed state, and the inkjet channel is disconnected from the inlet pipeline and the return pipeline. When the inlet pipeline delivers ink from the buffer bottle to the printhead assembly, the ink is delivered to the return pipeline and finally delivered back to the buffer bottle via the return pipeline. Therefore, before inkjet printing, the present invention circulates the ink in the inlet pipeline and the return pipeline, thereby removing all the tiny air bubbles attached to the inlet pipeline and the return pipeline, so as to avoid the air bubbles affecting normal inkjet printing. Especially for long-distance, complex and tortuous pipeline systems, the present invention can completely remove tiny air bubbles, avoiding ink interruption, ink splatter, or ink droplet deviation in the initial stage of inkjet printing, effectively improving print quality and consistency.

[0033] 2) During inkjet printing, the present invention switches the gas source switching valve to connect to the negative pressure gas source, while simultaneously closing the first solenoid valve and opening the second, third, and fourth solenoid valves to establish a negative pressure state in the gas source assembly. Since the liquid storage bottle and the buffer bottle are connected to the same negative pressure source at the same time, the gas pressure in the two bottles remains consistent. In this state, liquid replenishment can be controlled by the infusion pump to control the flow rate, and there is no gas pressure difference to interfere with the pressure in the buffer bottle, achieving true "zero-disturbance constant pressure liquid supply". This method is suitable for industrial coating applications where the printhead assembly has extremely high requirements for ink droplet weight accuracy and for fields with extremely high requirements for pressure stability, and can significantly improve printing consistency and system reliability. Attached Figure Description

[0034] Figure 1 This invention provides a schematic diagram of the pre-filling structure in a circulating ink supply system for inkjet printing.

[0035] Figure 2 This invention provides a schematic diagram of a slow-pressure circulating bubble removal system for inkjet printing.

[0036] Figure 3 This invention provides a schematic diagram of a re-positive pressure ink supply system for a dedicated circulating ink de-bubbling system for inkjet printing.

[0037] Figure 4 A schematic diagram of the liquid replenishment structure in a circulating de-bubbling ink supply system for inkjet printing provided by the present invention;

[0038] Figure 5 This invention provides a schematic diagram of the structure of an inkjet printing system for a dedicated circulating ink supply and de-bubbling system.

[0039] Figure 6 This invention provides a schematic diagram of the printhead assembly in a dedicated circulating ink supply system for inkjet printing.

[0040] Explanation of reference numerals in the attached figures:

[0041] 100. Printhead assembly; 101. Liquid inlet end; 102. Liquid return end; 103. Liquid inlet channel; 104. Liquid return channel; 105. Electrically controlled valve; 106. Inkjet channel; 107. Nozzle; 200. Buffer bottle; 201. Liquid inlet line; 202. Second solenoid valve; 203. Liquid return line; 204. Third solenoid valve; 300. Storage bottle; 301. Second air pressure branch pipe; 302. Infusion line; 303. Flow sensor; 304. First solenoid valve; 305. Infusion pump; 306. First air pressure branch pipe; 400. Air source switching valve; 401. Negative pressure air source; 402. Positive pressure air source; 403. Fourth solenoid valve; 404. Main air pressure pipe. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0043] Example 1

[0044] like Figures 1 to 2 as well as Figure 6 As shown in the figure, an inkjet printing-specific circulating ink supply system provided by an embodiment of the present invention includes a printhead assembly 100, one end of which is connected to an inlet pipe 201, and the other end of the inlet pipe 201 is connected to a buffer bottle 200. Specifically, in this embodiment, ink temporarily stored in the buffer bottle 200 can be delivered to the printhead assembly 100 through the inlet pipe 201 to achieve inkjet printing.

[0045] In this embodiment, the buffer bottle 200 is also connected to an infusion line 302, and the other end of the infusion line 302 is connected to a storage bottle 300 for storing ink. It can be noted that in this embodiment, the ink to be printed can be stored in the storage bottle 300 in advance. When ink is needed, the ink in the storage bottle 300 is delivered to the buffer bottle 200 through the infusion line 302. Correspondingly, as the ink in the buffer bottle 200 is output, this embodiment can deliver ink to the buffer bottle 200 in real time through the infusion line 302 to replenish the buffer bottle 200 in a timely manner.

[0046] Furthermore, this embodiment does not limit the volume of the buffer bottle 200 and the liquid storage bottle 300, as long as it meets the actual application requirements of the ink supply system.

[0047] Please see Figure 1 and Figure 6On the other side of the printhead assembly 100, a return line 203 is connected. The other end of the return line 203 is connected to the buffer bottle 200. The printhead assembly 100 includes a nozzle 107, which is connected to the inlet line 201 and the printhead assembly 100 via an inkjet channel 106. An electrically controlled valve 105 is provided between the inkjet channel 106, the inlet line 201, and the printhead assembly 100. The return line 203 is equipped with a return module, which is used to circulate the ink delivered by the inlet line 201 to the buffer bottle 200 via the return line 203 (see reference). Figure 2 );

[0048] It can be explained that, in order to remove residual air bubbles in the various pipelines and the printhead assembly 100 before inkjet printing, the electronically controlled valve 105 in this embodiment is in a closed state, and the inkjet channel 106 is disconnected from the inlet pipeline 201 and the return pipeline 203. When the inlet pipeline 201 delivers ink from the buffer bottle 200 to the printhead assembly 100, the ink is delivered to the return pipeline 203, and finally delivered back to the buffer bottle 200 via the return pipeline 203. Therefore, in this embodiment, before inkjet printing, by circulating the ink in the inlet pipeline 201 and the return pipeline 203, all the tiny air bubbles attached to the inlet pipeline 201 and the return pipeline 203 can be removed, so as to avoid the air bubbles affecting normal inkjet printing. Especially for long-distance, complex and tortuous pipeline systems, this embodiment can completely remove tiny air bubbles, avoiding ink interruption, ink splatter, or ink droplet deviation in the initial stage of inkjet printing, effectively improving print quality and consistency.

[0049] It should also be noted that after the ink has been circulating for a period of time, this embodiment opens the electronically controlled valve 105 so that the inkjet channel 106 is simultaneously connected to the liquid inlet pipe 201 and the nozzle 107, so that the ink transported by the liquid inlet pipe 201 can be transported to the nozzle 107, thereby realizing inkjet printing.

[0050] Furthermore, as a further embodiment, the buffer bottle 200 is set at a height greater than the printhead assembly 100. Specifically, in this embodiment, the buffer bottle 200 and the printhead assembly 100 are set at a certain height difference. The ink can be stably delivered to the printhead through the liquid level height difference, without the need for other power sources for liquid delivery.

[0051] Example 2

[0052] Based on Example 1, please refer to Figure 1 and Figure 6To connect the printhead assembly 100 to the inlet pipe 201 and the return pipe 203, an inlet end 101 is provided on one side of the printhead assembly 100. One end of the inlet end 101 is connected to the inlet channel 103 in the printhead assembly 100, and the other end is connected to the inlet pipe 201. A return end 102 is provided on the other side of the printhead assembly 100. One end of the return end 102 is connected to the return channel 104 in the printhead assembly 100. The nozzle 107 is connected to the inlet channel 103 and the return channel 104. The electronically controlled valve 105 is located in the inkjet channel 106. It can be explained that when the inlet pipe 201 is supplying ink, the ink is first delivered to the inlet channel 103 through the inlet end 101, then to the return channel 104, and finally output to the return pipe 203 through the return end 102, completing one cycle.

[0053] Furthermore, this embodiment does not limit the specific structure and model of the electrically controlled valve 105, as long as it meets the requirements of the reversing infusion in this embodiment.

[0054] In this embodiment, the end of the return line 203 away from the printhead assembly 100 is connected to the infusion line 302. The connection end of the two is located on the side of the infusion line 302 that is closer to the buffer bottle 200. The infusion line 302 has an inverted U-shaped structure. It should be noted that when the ink is delivered from the return line 203 to the buffer bottle 200, it is first delivered to the infusion line 302 and then flows back to the buffer bottle 200 via the infusion line 302.

[0055] As a further embodiment, the return module includes an infusion pump 305 disposed on the infusion line 302. The infusion pump 305 is disposed between the end of the return line 203 and the buffer bottle 200. Specifically, when circulating ink, the infusion pump 305 can be started, and the infusion pump 305 can drive the ink to flow at a low speed between the inlet line 201 and the return line 203 to expel residual micro air bubbles in the system.

[0056] In this embodiment, when the infusion pump 305 is performing cyclic infusion, in order to prevent ink from flowing back from the infusion tube 302 into the storage bottle 300, a first solenoid valve 304 is provided on the infusion tube 302. The first solenoid valve 304 is located between the end of the return tube 203 and the storage bottle 300. Specifically, when the ink is being cyclically transported, this embodiment can use the first solenoid valve 304 to cut off the infusion tube 302, so that the ink is only transported towards the buffer bottle 200, thus avoiding backflow.

[0057] Please see Figure 1 and Figure 3In order to replenish the ink in the storage bottle 300 to the buffer bottle 200, this embodiment can deliver the ink in the storage bottle 300 to the buffer bottle 200 through the infusion tube 302. Correspondingly, in order to prevent the ink in the buffer bottle 200 from being drawn out again through the inlet tube 201 and the return tube 203, in this embodiment, the inlet tube 201 is provided with a second solenoid valve 202. It can be noted that, in this embodiment, during the process of replenishing the buffer bottle 200, the infusion pump 305 can disconnect the inlet tube 201 in advance through the second solenoid valve 202 to prevent the ink in the buffer bottle 200 from flowing to the printhead assembly 100 through the inlet tube 201 during the replenishment process.

[0058] Accordingly, during normal inkjet printing, as ink in the inlet line 201 is transported towards the inkjet channel 106, to prevent ink from entering the return line 203 and flowing back, in this embodiment, please refer to... Figure 1 The return line 203 is equipped with a third solenoid valve 204. Specifically, in this embodiment, during the inkjet printing process, the return line 203 can be disconnected in advance by the third solenoid valve 204 to prevent ink from flowing back into the return line 203.

[0059] As a further embodiment, in order to push the ink through the buffer bottle 200 to the printhead assembly 100, the buffer bottle 200 is provided with a first air pressure branch pipe 306. The end of the first air pressure branch pipe 306 away from the buffer bottle 200 is connected to the air pressure main pipe 404, and the end of the air pressure main pipe 404 is connected to the air source assembly. It can be noted that when this embodiment needs to deliver the ink in the buffer bottle 200 to the printhead assembly 100, positive pressure can be delivered to the air pressure main pipe 404 through the air source assembly. The positive pressure is delivered to the buffer bottle 200 by the first air pressure branch pipe 306, and then the ink in the buffer bottle 200 can be pressed to the liquid inlet pipe 201 under pressure.

[0060] Furthermore, in this embodiment, to replenish the ink in the storage bottle 300 and transfer it to the buffer bottle 200, please refer to [link to relevant documentation]. Figure 1 and Figure 4 The liquid storage bottle 300 is also connected to a second pneumatic branch pipe 301. The end of the second pneumatic branch pipe 301 away from the liquid storage bottle 300 is connected to the pneumatic main pipe 404. It can be explained that when it is necessary to replenish the buffer bottle 200, the first solenoid valve 304 is closed, and positive pressure is generated through the air source component. The positive pressure is delivered to the liquid storage bottle 300 through the pneumatic main pipe 404 and the second pneumatic branch pipe 301. Under the action of the positive pressure, the ink in the liquid storage bottle 300 can be delivered to the buffer bottle 200 through the infusion pipe 302.

[0061] In this embodiment, the gas source assembly includes a gas source switching valve 400 disposed at the end of the gas pressure main pipe 404, and the other end of the gas source switching valve 400 is connected to the positive pressure gas source 402; wherein, a fourth solenoid valve 403 is also provided between the gas pressure main pipes 404; specifically, in this embodiment, when replenishing pressure to the liquid storage bottle 300 or the buffer bottle 200, the fourth solenoid valve 403 is opened, and the positive pressure can be delivered to the gas pressure main pipe 404 through the positive pressure gas source 402.

[0062] Furthermore, in the negative pressure ink supply system, as the ink is gradually consumed, the liquid level in the buffer bottle 200 continuously decreases, and the change in liquid column height causes fluctuations in the negative pressure of the system. In order to reduce the sensitivity of the printhead assembly 100 to the ink supply pressure height, in this embodiment, the air source assembly also includes a negative pressure air source 401 connected to the air source switching valve 400; the air source switching valve 400 in this embodiment can switch its connection with the positive pressure air source 402 or the negative pressure air source 401 in real time, so as to adjust the air pressure main pipe 404 to generate positive or negative pressure in real time.

[0063] It can be explained that during inkjet printing, the air source switching valve 400 switches its connection to the negative pressure air source 401, while simultaneously closing the first solenoid valve 304 and opening the second solenoid valve 202, the third solenoid valve 204, and the fourth solenoid valve 403, so that the air source assembly establishes a negative pressure state. Since the liquid storage bottle 300 and the buffer bottle 200 are connected to the same negative pressure source at the same time, the air pressure in the two bottles remains consistent. In this state, liquid replenishment can be controlled by the infusion pump 305, and there is no pressure difference to interfere with the pressure of the buffer bottle 200, achieving true "zero-disturbance constant pressure liquid supply". This method is suitable for industrial coating applications where the printhead assembly 100 has extremely high requirements for ink droplet weight accuracy and for fields with extremely high requirements for pressure stability, and can significantly improve printing consistency and system reliability.

[0064] A circulating ink supply and de-bubbling method for inkjet printing includes the following steps:

[0065] Please see Figure 1 S1, Pre-filling with ink: The air source switching valve 400 is switched to connect with the positive pressure air source 402, the fourth solenoid valve 403 and the second solenoid valve 202 are opened, and the first solenoid valve 304 and the third solenoid valve 204 are closed; the positive pressure air source 402 pushes the ink through the buffer bottle 200 into the printhead assembly 100 and the pipeline, completing the pre-filling with ink;

[0066] Please see Figure 2 S2, Slow-pressure circulation defoaming: Close the fourth solenoid valve 403, open the first solenoid valve 304, the second solenoid valve 202, and the third solenoid valve 204, start the infusion pump 305 to form a closed loop circulation, the ink flows at a low speed, and effectively removes residual microbubbles in the system.

[0067] Please see Figure 3S3, Press ink again with positive pressure: The air source switching valve 400 maintains positive pressure, opens the fourth solenoid valve 403 and the second solenoid valve 202, and closes the first solenoid valve 304 and the third solenoid valve 204. The positive pressure is used to further remove trace residual air bubbles and ensure that air bubbles in the system are completely removed.

[0068] Please see Figure 4 S4, Replenishing ink: Open the first solenoid valve 304, close the second solenoid valve 202, the third solenoid valve 204, and the fourth solenoid valve 403. The ink is replenished from the storage bottle 300 to the buffer bottle 200 to ensure the liquid level.

[0069] Please see Figure 5 S5. Switching to negative pressure to prepare for printing: The air source switching valve 400 is switched to connect with the negative pressure air source 401. The fourth solenoid valve 403, the second solenoid valve 202, and the third solenoid valve 204 are opened, and the first solenoid valve 304 is closed. The system establishes a stable negative pressure and enters the printing operation state.

[0070] Example 3

[0071] In this embodiment, the infusion pump 305 is not used for ink circulation. Instead, the control system drives the air source switching valve 400 to alternately apply positive and negative pressure to the top of the storage bottle 300 or the buffer bottle 200, forming periodic air pressure fluctuations.

[0072] This method creates a micro-fluid disturbance in the pipeline, which can drive the air bubbles in the ink supply path to migrate along the pressure gradient and finally push them to the exhaust ports or return channels set at both ends of the printhead assembly 100, thereby preventing air bubbles from entering the nozzle 107. This embodiment is suitable for small inkjet systems with compact structures or without circulation paths, and can effectively complete air bubble transfer before printing, improving initial printing stability.

[0073] Example 4

[0074] In this embodiment, a miniature flow sensor 303 is installed between the infusion tubes 302 to monitor the infusion flow rate in real time. The control system collects the flow signal of this section of the passage in real time and calculates the actual ink consumption per unit time. Based on the calculation result, the infusion pump 305 is controlled to accurately replenish the same amount of ink, realizing the ink supply strategy of "replenishing only what is consumed". It can maintain the pressure stability in the buffer bottle 200 without the need for a liquid level sensor or isobaric structure, ensuring the consistency of liquid supply during continuous inkjet printing. It is suitable for high-frequency or multi-printhead systems and has high responsiveness and structural flexibility.

[0075] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A circulating ink supply system for inkjet printing, comprising a printhead assembly (100), characterized in that, One end of the nozzle assembly (100) is connected to the liquid inlet pipe (201), and the other end of the liquid inlet pipe (201) is connected to the buffer bottle (200); The buffer bottle (200) is also connected to an infusion line (302), and the other end of the infusion line (302) is connected to a storage bottle (300) for storing ink. The other side of the printhead assembly (100) is also connected to a return line (203), and the other end of the return line (203) is connected to a buffer bottle (200). The printhead assembly (100) includes a nozzle (107), which is connected to the inlet line (201) and the printhead assembly (100) through an inkjet channel (106). An electronically controlled valve (105) is provided between the inkjet channel (106), the inlet line (201), and the printhead assembly (100). The return pipeline (203) is equipped with a return module, which is used to circulate the ink transported by the inlet pipeline (201) to the buffer bottle (200) through the return pipeline (203); A liquid inlet end (101) is provided on one side of the printhead assembly (100). One end of the liquid inlet end (101) is connected to the liquid inlet channel (103) in the printhead assembly (100), and the other end is connected to the liquid inlet pipe (201). A liquid return end (102) is provided on the other side of the printhead assembly (100). One end of the liquid return end (102) is connected to the liquid return channel (104) in the printhead assembly (100). The nozzle (107) is connected to the liquid inlet channel (103) and the liquid return channel (104). An electronically controlled valve (105) is installed in the inkjet channel (106). A first air pressure branch pipe (306) is provided on the buffer bottle (200). One end of the tube (306) away from the buffer bottle (200) is connected to the main pressure pipe (404), and the end of the main pressure pipe (404) is connected to the gas source assembly; a second pressure branch pipe (301) is also connected to the liquid storage bottle (300), and one end of the second pressure branch pipe (301) away from the liquid storage bottle (300) is connected to the main pressure pipe (404); the gas source assembly includes a gas source switching valve (400) located at the end of the main pressure pipe (404), and the other end of the gas source switching valve (400) is connected to the positive pressure gas source (402); a fourth solenoid valve (403) is also provided between the main pressure pipes (404); the gas source assembly also includes a negative pressure gas source (401) connected to the gas source switching valve (400).

2. The inkjet printing-specific circulating ink supply and de-bubbling system as described in claim 1, characterized in that, The end of the return line (203) away from the nozzle assembly (100) is connected to the infusion line (302), and the connection end of the two is located on the side of the infusion line (302) closer to the buffer bottle (200); The infusion line (302) has an inverted U-shaped structure.

3. The inkjet printing-specific circulating ink supply and de-bubbling system as described in claim 2, characterized in that, The return module includes an infusion pump (305) installed on the infusion line (302), and the infusion pump (305) is located between the end of the return line (203) and the buffer bottle (200).

4. The inkjet printing-specific circulating ink supply and de-bubbling system as described in claim 3, characterized in that, The infusion pipeline (302) is equipped with a first solenoid valve (304), which is located between the end of the return pipeline (203) and the storage bottle (300). The inlet pipe (201) is equipped with a second solenoid valve (202); the return pipe (203) is equipped with a third solenoid valve (204).

5. A circulating ink supply and de-bubbling method for inkjet printing, characterized in that, The ink supply system for inkjet printing as described in claim 4 includes the following steps: Pre-filling ink: The air source switching valve (400) is switched to connect with the positive pressure air source (402), the fourth solenoid valve (403) and the second solenoid valve (202) are opened, and the first solenoid valve (304) and the third solenoid valve (204) are closed; the positive pressure air source (402) pushes the ink through the buffer bottle (200) into the printhead assembly (100) and pipeline to complete the pre-filling ink; Slow-pressure circulation defoaming: Close the fourth solenoid valve (403), open the first solenoid valve (304), the second solenoid valve (202), and the third solenoid valve (204), start the infusion pump (305) to form a closed loop circulation, the ink flows at a low speed, and effectively removes residual micro bubbles in the system; Press ink again with positive pressure: The air source switching valve (400) maintains positive pressure, opens the fourth solenoid valve (403) and the second solenoid valve (202), and closes the first solenoid valve (304) and the third solenoid valve (204) to further remove trace residual air bubbles and ensure that air bubbles in the system are completely removed; Replenishment: Open the first solenoid valve (304), close the second solenoid valve (202), the third solenoid valve (204), and the fourth solenoid valve (403), and the ink is replenished from the storage bottle (300) to the buffer bottle (200) to ensure the liquid level. Switching to negative pressure to prepare for printing: The air source switching valve (400) is switched to connect with the negative pressure air source (401), the fourth solenoid valve (403), the second solenoid valve (202), and the third solenoid valve (204) are opened, and the first solenoid valve (304) is closed. The system establishes a stable negative pressure and enters the printing operation state.

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