An ink path three-level protection system and method of a 3D inkjet printing device

Abstract

The application discloses a kind of ink path three-level protection system and method of 3D inkjet printing device.The system includes negative pressure system, nozzle, ink inlet bottle, ink return bottle, ink inlet safety buffer bottle, ink return safety buffer bottle, ink inlet bottle normally closed electromagnetic valve, ink return bottle normally closed electromagnetic valve, ink inlet bottle two-way electromagnetic valve, ink return bottle two-way electromagnetic valve, ink return safety buffer bottle two-way electromagnetic valve, ink inlet safety buffer bottle two-way electromagnetic valve, ink return bottle ink pump, ink inlet bottle ink pump, ink return butterfly filter and ink inlet butterfly filter.When negative pressure system starts to work, suction force is generated on residual ink in nozzle, and ink enters ink return bottle;Through ink inlet bottle and ink return bottle high liquid level float ball, ink inlet and ink return safety buffer bottle low liquid level float ball, ink inlet and ink return safety buffer bottle high liquid level float ball, ink path three-level protection is carried out.The application reduces the risk of 3D inkjet printing device ink backflow into negative pressure system, improves the safety, reliability and stability of equipment operation of system.

Description

Technical Field

[0001] This invention relates to the field of 3D inkjet printing technology, and in particular to a three-level ink path protection system and method for a 3D inkjet printing device. Background Technology

[0002] A 3D inkjet printer is a device that prints patterns onto filaments by jetting ink. The printhead is the core component of a 3D inkjet printer, and its safety is crucial. Typically, inkjet printers are equipped with a negative pressure system to create negative pressure and draw out residual ink from the printhead, preventing clogging. When the ink path protection system malfunctions, excessive residual ink can easily accumulate in the ink inlet and return bottles. In more serious cases, residual ink can fill the safety buffer bottle and continuously overflow into the negative pressure system, causing damage and failure of the negative pressure system.

[0003] Ink path protection systems typically use sensors to control solenoid valves. These valves open and close based on ink level, preventing ink from flowing into the negative pressure system and thus protecting it from damage. Ink path protection systems involve sensor technology and control logic. By combining these technologies, inkjet printer printheads and negative pressure systems can achieve further safety protection to cope with extreme situations and ensure the safe and stable operation of the device.

[0004] Patent CN 219505672 U discloses a protective device for an inkjet printhead and an inkjet printing device, which uses an inert gas atmosphere to protect the inkjet printhead and prevent it from clogging; Patent CN201010147577 discloses a wiper maintenance device for an inkjet printer, which can protect the printhead when it is not working by keeping it moist. Existing research mainly focuses on printhead protection and lacks research on ink path system protection. Summary of the Invention

[0005] The purpose of this invention is to provide an ink path protection system and method for a 3D inkjet printing device that can solve the problem of negative pressure system damage caused by ink backflow during inkjet printing and provide reliable protection for the safe and stable operation of the equipment.

[0006] The technical solution to achieve the purpose of this invention is: a three-level ink circuit protection system for a 3D inkjet printing device, including a negative pressure system, a printhead, an ink inlet bottle, an ink return bottle, an ink inlet safety buffer bottle, an ink return safety buffer bottle, a normally closed solenoid valve for the ink inlet bottle, a normally closed solenoid valve for the ink return bottle, a two-way solenoid valve for the ink inlet bottle, a two-way solenoid valve for the ink return safety buffer bottle, a two-way solenoid valve for the ink inlet safety buffer bottle, an ink return bottle ink pump, an ink inlet bottle ink pump, an ink return butterfly filter, and an ink inlet butterfly filter;

[0007] The ink inlet of the ink bottle is connected to the ink pump. A one-way valve is installed at the front end of the ink pump to connect to the ink inlet butterfly filter. The lower end of the ink bottle is connected to the normally closed solenoid valve and is connected to the printhead through a pipe. The upper end is connected to the two-way solenoid valve. The two-way solenoid valve is connected to the ink inlet of the ink safety buffer bottle. The ink outlet of the ink safety buffer bottle is connected to the two-way solenoid valve. The two-way solenoid valve is connected to the negative pressure system.

[0008] The ink return end of the ink return bottle is connected to the ink return pump. The ink return end of the ink return pump is equipped with a one-way valve connected to the ink return butterfly filter. The lower end of the ink return bottle is connected to the normally closed solenoid valve of the ink return bottle and is connected to the printhead through a pipe. The upper end is connected to the two-way solenoid valve of the ink return bottle. The two-way solenoid valve of the ink return bottle is connected to the ink inlet of the ink return safety buffer bottle. The ink outlet of the ink return safety buffer bottle is connected to the two-way solenoid valve of the ink return safety buffer bottle. The two-way solenoid valve of the ink return safety buffer bottle is connected to the negative pressure system.

[0009] Furthermore, the ink bottle is equipped with a low-level float and a high-level float. The low-level float controls the opening and closing of the ink pump, and the high-level float controls the opening and closing of the two-way solenoid valve.

[0010] Furthermore, the ink return bottle is equipped with a low-level float and a high-level float. The low-level float controls the opening and closing of the ink pump, and the high-level float controls the opening and closing of the two-way solenoid valve.

[0011] Furthermore, the ink inlet safety buffer bottle is equipped with a low-level float and a high-level float; the low-level float is used to control the switch of the negative pressure system, and the high-level float is used to control the opening and closing of the two-way solenoid valve.

[0012] Furthermore, the ink return safety buffer bottle is equipped with a low-level float and a high-level float; the low-level float is used to control the switch of the negative pressure system, and the high-level float is used to control the opening and closing of the two-way solenoid valve.

[0013] A three-level ink path protection method for a 3D inkjet printer, the method being based on the aforementioned three-level ink path protection system of the 3D inkjet printer, includes the following steps:

[0014] Step 1: When the negative pressure system starts working, it generates suction on the residual ink in the printhead, and the ink enters the ink return bottle;

[0015] Step 2: The first layer of protection is achieved through the low-level float ball of the ink inlet bottle, the high-level float ball of the ink inlet bottle, the low-level float ball of the ink return bottle, and the high-level float ball of the ink return bottle.

[0016] Step 3: A second layer of protection is provided by using the low-level float ball of the ink inlet safety buffer bottle and the low-level float ball of the ink return safety buffer bottle;

[0017] Step 4: A third layer of protection is provided by using the high-level float of the ink inlet safety buffer bottle and the high-level float of the ink return safety buffer bottle.

[0018] Furthermore, in step 2, the first layer of protection is achieved through the low-level float of the ink inlet bottle, the high-level float of the ink inlet bottle, the low-level float of the ink return bottle, and the high-level float of the ink return bottle, as detailed below:

[0019] When the ink level in the ink inlet reaches the height of the low-level float of the ink inlet or the ink level in the ink return bottle reaches the height of the low-level float of the ink return bottle, the sensor controls the ink pump in the ink inlet or the ink return bottle to shut down. When the ink level in the ink inlet reaches the height of the high-level float of the ink inlet or the ink return bottle reaches the height of the high-level float of the ink return bottle, the sensor controls the two-way solenoid valve in the ink inlet or the two-way solenoid valve in the ink return bottle to close, preventing ink from continuing to overflow, thus achieving the first layer of protection.

[0020] Furthermore, in step 3, a second layer of protection is provided through the low-level floats of the ink inlet safety buffer bottle and the ink return safety buffer bottle, as detailed below:

[0021] If the malfunction continues and closing the two-way solenoid valve of the ink inlet bottle or the two-way solenoid valve of the ink return bottle fails to prevent ink backflow, ink will continue to flow into the ink inlet safety buffer bottle or the ink return safety buffer bottle. When the liquid level in the ink inlet safety buffer bottle reaches the height of the low liquid level float of the ink inlet safety buffer bottle or the liquid level in the ink return safety buffer bottle reaches the height of the low liquid level float of the ink return safety buffer bottle, the sensor controls the negative pressure system to shut down, so that the suction force generated by the negative pressure system disappears, preventing ink from further backflow, thus achieving a second layer of protection.

[0022] Furthermore, in step 4, a third layer of protection is provided through the high-level floats of the ink inlet safety buffer bottle and the ink return safety buffer bottle, as detailed below:

[0023] If ink continues to overflow, when the liquid level in the ink inlet safety buffer bottle reaches the height of the high-level float of the ink inlet safety buffer bottle or the liquid level in the return ink safety buffer bottle reaches the height of the high-level float of the return ink safety buffer bottle, the sensor controls the two-way solenoid valve of the ink inlet safety buffer bottle or the two-way solenoid valve of the return ink safety buffer bottle to close, preventing ink from entering the negative pressure system, thus achieving the third layer of protection.

[0024] Compared with the prior art, the significant advantages of this invention are: (1) This system uses three-level protection measures to prevent the ink from rapidly overflowing into the negative pressure system due to equipment failure of the 3D inkjet printing device, thereby reducing the safety risks of the equipment and improving the safety of the system; (2) The adoption of three-level protection measures improves the reliability of protection and the stability of equipment operation. Attached Figure Description

[0025] Figure 1 This is a structural block diagram of a three-level ink path protection system for a 3D inkjet printing device according to the present invention.

[0026] Figure 2 This is a flowchart illustrating a three-level ink path protection method for a 3D inkjet printing device according to the present invention. Detailed Implementation

[0027] This invention provides a three-level ink path protection system for a 3D inkjet printer, including a negative pressure system 1, a printhead 2, an ink inlet bottle 3, an ink return bottle 4, an ink inlet safety buffer bottle 5, an ink return safety buffer bottle 6, a normally closed solenoid valve for the ink inlet bottle 7, a normally closed solenoid valve for the ink return bottle 8, a two-way solenoid valve for the ink inlet bottle 9, a two-way solenoid valve for the ink return bottle 10, a two-way solenoid valve for the ink return safety buffer bottle 11, a two-way solenoid valve for the ink inlet safety buffer bottle 12, an ink return bottle ink pump 21, an ink inlet bottle ink pump 22, an ink return butterfly filter 23, and an ink inlet butterfly filter 24;

[0028] The ink inlet of the ink bottle 3 is connected to the ink pump 22. A one-way valve is provided at the front end of the ink pump 22 to connect to the ink butterfly filter 24. The lower end of the ink bottle 3 is connected to the normally closed solenoid valve 7 and is connected to the print head 2 through a pipe. The upper end is connected to the two-way solenoid valve 9. The two-way solenoid valve 9 is connected to the ink inlet of the ink safety buffer bottle 5. The ink outlet of the ink safety buffer bottle 5 is connected to the two-way solenoid valve 12. The two-way solenoid valve 12 is connected to the negative pressure system 1.

[0029] The ink return bottle 4 is connected to the ink return bottle pump 21 at its ink return end. The ink return end of the ink return bottle pump 21 is equipped with a one-way valve connected to the ink return butterfly filter 23. The lower end of the ink return bottle 4 is connected to the normally closed solenoid valve 8 of the ink return bottle and is connected to the print head 2 through a pipe. The upper end is connected to the two-way solenoid valve 10 of the ink return bottle. The two-way solenoid valve 10 of the ink return bottle is connected to the ink inlet of the ink return safety buffer bottle 6. The ink outlet of the ink return safety buffer bottle 6 is connected to the two-way solenoid valve 11 of the ink return safety buffer bottle. The two-way solenoid valve 11 of the ink return safety buffer bottle is connected to the negative pressure system 1.

[0030] As a specific example, the ink bottle 3 is equipped with a low-level float 13 and a high-level float 14. The low-level float 13 is used to control the opening and closing of the ink pump 22, and the high-level float 14 is used to control the opening and closing of the two-way solenoid valve 9.

[0031] As a specific example, the ink return bottle 4 is equipped with a low-level float 15 and a high-level float 16. The low-level float 15 is used to control the opening and closing of the ink pump 21, and the high-level float 16 is used to control the opening and closing of the two-way solenoid valve 10.

[0032] As a specific example, the ink inlet safety buffer bottle 5 is equipped with a low-level float 19 and a high-level float 20; the low-level float 19 is used to control the switch of the negative pressure system 1, and the high-level float 20 is used to control the opening and closing of the two-way solenoid valve 12.

[0033] As a specific example, the ink return safety buffer bottle 6 is equipped with a low-level float 17 and a high-level float 18 inside the ink return safety buffer bottle; the low-level float 17 is used to control the switch of the negative pressure system 1, and the high-level float 18 is used to control the opening and closing of the two-way solenoid valve 11 of the ink return safety buffer bottle.

[0034] The present invention also provides a three-level ink path protection method for a 3D inkjet printing device. This method, based on the aforementioned three-level ink path protection system for the 3D inkjet printing device, includes the following steps:

[0035] Step 1: When the negative pressure system 1 starts working, it generates suction on the residual ink in the printhead, and the ink enters the ink return bottle 4;

[0036] Step 2: The first layer of protection is achieved through the low-level float ball 13 of the ink inlet bottle, the high-level float ball 14 of the ink inlet bottle, the low-level float ball 15 of the ink return bottle, and the high-level float ball 16 of the ink return bottle.

[0037] Step 3: A second layer of protection is provided through the low-level float ball 19 of the ink inlet safety buffer bottle and the low-level float ball 17 of the ink return safety buffer bottle;

[0038] Step 4: A third layer of protection is provided through the high-level float 20 of the ink inlet safety buffer bottle and the high-level float 18 of the ink return safety buffer bottle.

[0039] As a specific example, in step 2, the first layer of protection is achieved through the low-level float 13 of the ink inlet bottle, the high-level float 14 of the ink inlet bottle, the low-level float 15 of the ink return bottle, and the high-level float 16 of the ink return bottle, as detailed below:

[0040] When the ink level in the ink inlet bottle 3 reaches the height of the low-level float 13 or the ink level in the return ink bottle 4 reaches the height of the low-level float 15, the sensor controls the ink pump 22 in the ink inlet bottle or the ink pump 21 in the return ink bottle to shut down. When the ink level in the ink inlet bottle 3 reaches the height of the high-level float 14 or the ink level in the return ink bottle 4 reaches the height of the high-level float 16, the sensor controls the two-way solenoid valve 9 in the ink inlet bottle or the two-way solenoid valve 10 in the return ink bottle to shut down, preventing ink from continuing to overflow and achieving the first layer of protection.

[0041] As a specific example, in step 3, a second layer of protection is provided through the low-level float 19 of the ink inlet safety buffer bottle and the low-level float 17 of the ink return safety buffer bottle, as detailed below:

[0042] When the malfunction continues, if closing the two-way solenoid valve 9 of the ink inlet bottle or the two-way solenoid valve 10 of the ink return bottle fails to prevent ink backflow, ink will continue to flow into the ink inlet safety buffer bottle 5 or the ink return safety buffer bottle 6. When the liquid level in the ink inlet safety buffer bottle 5 reaches the height of the low liquid level float 19 of the ink inlet safety buffer bottle or the liquid level in the ink return safety buffer bottle 6 reaches the height of the low liquid level float 17 of the ink return safety buffer bottle, the sensor controls the negative pressure system 1 to close, so that the suction force generated by the negative pressure system 1 disappears, preventing ink from further backflow and achieving a second layer of protection.

[0043] As a specific example, in step 4, a third layer of protection is provided through the high-level float 20 of the ink inlet safety buffer bottle and the high-level float 18 of the ink return safety buffer bottle, as detailed below:

[0044] If the ink continues to overflow, when the liquid level in the ink inlet safety buffer bottle 5 reaches the height of the high-level float 20 of the ink inlet safety buffer bottle or the liquid level in the return ink safety buffer bottle 6 reaches the height of the high-level float 18 of the return ink safety buffer bottle, the sensor controls the two-way solenoid valve 12 of the ink inlet safety buffer bottle or the two-way solenoid valve 11 of the return ink safety buffer bottle to close, preventing ink from entering the negative pressure system 1, thus achieving the third layer of protection.

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0046] Example

[0047] Combination Figure 1This embodiment provides a three-level ink circuit protection system for a 3D inkjet printer, including a negative pressure system 1, a printhead 2, an ink inlet bottle 3, an ink return bottle 4, an ink inlet safety buffer bottle 5, an ink return safety buffer bottle 6, a normally closed solenoid valve for the ink inlet bottle 7, a normally closed solenoid valve for the ink return bottle 8, a two-way solenoid valve for the ink inlet bottle 9, a two-way solenoid valve for the ink return bottle 10, a two-way solenoid valve for the ink return safety buffer bottle 11, a two-way solenoid valve for the ink inlet safety buffer bottle 12, an ink return bottle ink pump 21, an ink inlet bottle ink pump 22, an ink return butterfly filter 23, and an ink inlet butterfly filter 24.

[0048] The ink inlet of the ink bottle 3 is connected to the ink pump 22. A one-way valve is provided at the front end of the ink pump 22 to connect to the ink butterfly filter 24. The lower end of the ink bottle 3 is connected to the normally closed solenoid valve 7 and is connected to the print head 2 through a pipe. The upper end is connected to the two-way solenoid valve 9. The two-way solenoid valve 9 is connected to the ink inlet of the ink safety buffer bottle 5. The ink outlet of the ink safety buffer bottle 5 is connected to the two-way solenoid valve 12. The two-way solenoid valve 12 is connected to the negative pressure system 1.

[0049] The ink return bottle 4 is connected to the ink return bottle pump 21 at its ink return end. The ink return end of the ink return bottle pump 21 is equipped with a one-way valve connected to the ink return butterfly filter 23. The lower end of the ink return bottle 4 is connected to the normally closed solenoid valve 8 of the ink return bottle and is connected to the print head 2 through a pipe. The upper end is connected to the two-way solenoid valve 10 of the ink return bottle. The two-way solenoid valve 10 of the ink return bottle is connected to the ink inlet of the ink return safety buffer bottle 6. The ink outlet of the ink return safety buffer bottle 6 is connected to the two-way solenoid valve 11 of the ink return safety buffer bottle. The two-way solenoid valve 11 of the ink return safety buffer bottle is connected to the negative pressure system 1.

[0050] Furthermore, the ink bottle 3 is equipped with a low-level float ball 13 and a high-level float ball 14. The low-level float ball 13 is used to control the opening and closing of the ink pump 22, and the high-level float ball 14 is used to control the opening and closing of the two-way solenoid valve 9.

[0051] Furthermore, the ink return bottle 4 is equipped with a low-level float 15 and a high-level float 16. The low-level float 15 is used to control the opening and closing of the ink pump 21, and the high-level float 16 is used to control the opening and closing of the two-way solenoid valve 10.

[0052] Furthermore, the ink inlet safety buffer bottle 5 is equipped with a low-level float 19 and a high-level float 20; the low-level float 19 is used to control the switch of the negative pressure system 1, and the high-level float 20 is used to control the opening and closing of the two-way solenoid valve 12.

[0053] Furthermore, the ink return safety buffer bottle 6 is equipped with a low-level float 17 and a high-level float 18 inside the ink return safety buffer bottle; the low-level float 17 is used to control the switch of the negative pressure system 1, and the high-level float 18 is used to control the opening and closing of the two-way solenoid valve 11 of the ink return safety buffer bottle.

[0054] Combination Figure 2 This embodiment also provides a three-level ink path protection method for a 3D inkjet printing device, including the following steps:

[0055] Step 1: When the negative pressure system 1 starts working, it generates suction on the residual ink in the printhead, and the ink enters the ink return bottle 4;

[0056] Step 2: When the ink level in the ink inlet bottle 3 reaches the height of the low-level float ball 13 or the ink level in the return ink bottle 4 reaches the height of the low-level float ball 15, the sensor controls the ink pump 22 in the ink inlet bottle or the ink pump 21 in the return ink bottle to shut down. When the ink level in the ink inlet bottle 3 reaches the height of the high-level float ball 14 or the ink level in the return ink bottle 4 reaches the height of the high-level float ball 16, the sensor controls the two-way solenoid valve 9 in the ink inlet bottle or the two-way solenoid valve 10 in the return ink bottle to shut down, preventing ink from continuing to overflow and achieving the first layer of protection.

[0057] Step 3: When the fault continues to occur, if closing the two-way solenoid valve 9 of the ink inlet bottle or the two-way solenoid valve 10 of the ink return bottle cannot prevent ink backflow, ink continues to flow into the ink inlet safety buffer bottle 5 or the ink return safety buffer bottle 6. When the liquid level in the ink inlet safety buffer bottle 5 reaches the height of the low liquid level float 19 of the ink inlet safety buffer bottle or the liquid level in the ink return safety buffer bottle 6 reaches the height of the low liquid level float 17 of the ink return safety buffer bottle, the sensor controls the negative pressure system 1 to close, so that the suction force generated by the negative pressure system 1 disappears, preventing ink from further backflow, thus achieving the second layer of protection.

[0058] Step 4: If the ink continues to overflow, when the liquid level in the ink inlet safety buffer bottle 5 reaches the height of the high liquid level float 20 of the ink inlet safety buffer bottle or the liquid level in the return ink safety buffer bottle 6 reaches the height of the high liquid level float 18 of the return ink safety buffer bottle, the sensor controls the two-way solenoid valve 12 of the ink inlet safety buffer bottle or the two-way solenoid valve 11 of the return ink safety buffer bottle to close, preventing ink from entering the negative pressure system 1, thus achieving the third layer of protection.

[0059] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A three-level ink path protection system for a 3D inkjet printing device, characterized in that, Includes a negative pressure system (1), printhead (2), ink inlet bottle (3), ink return bottle (4), ink inlet safety buffer bottle (5), ink return safety buffer bottle (6), normally closed solenoid valve of ink inlet bottle (7), normally closed solenoid valve of ink return bottle (8), two-way solenoid valve of ink inlet bottle (9), two-way solenoid valve of ink return bottle (10), two-way solenoid valve of ink return safety buffer bottle (11), two-way solenoid valve of ink inlet safety buffer bottle (12), ink pump of ink return bottle (21), ink pump of ink inlet bottle (22), ink return butterfly filter (23), and ink inlet butterfly filter (24); The ink inlet of the ink bottle (3) is connected to the ink pump (22). The front end of the ink pump (22) is equipped with a one-way valve connected to the ink butterfly filter (24). The lower end of the ink bottle (3) is connected to the normally closed solenoid valve (7) of the ink bottle and connected to the print head (2) through a pipe. The upper end is connected to the two-way solenoid valve (9) of the ink bottle. The two-way solenoid valve (9) of the ink bottle is connected to the ink inlet of the ink safety buffer bottle (5). The ink outlet of the ink safety buffer bottle (5) is connected to the two-way solenoid valve (12) of the ink safety buffer bottle. The two-way solenoid valve (12) of the ink safety buffer bottle is connected to the negative pressure system (1). The ink return bottle (4) is connected to the ink return bottle pump (21) at the ink return end. The ink return end of the ink return bottle pump (21) is equipped with a one-way valve connected to the ink return butterfly filter (23). The lower end of the ink return bottle (4) is connected to the normally closed solenoid valve (8) of the ink return bottle and is connected to the print head (2) through a pipe. The upper end is connected to the two-way solenoid valve (10) of the ink return bottle. The two-way solenoid valve (10) of the ink return bottle is connected to the ink inlet of the ink return safety buffer bottle (6). The ink outlet of the ink return safety buffer bottle (6) is connected to the two-way solenoid valve (11) of the ink return safety buffer bottle. The two-way solenoid valve (11) of the ink return safety buffer bottle is connected to the negative pressure system (1). The ink bottle (3) is equipped with a low-level float (13) and a high-level float (14). The low-level float (13) is used to control the opening and closing of the ink pump (22) and the high-level float (14) is used to control the opening and closing of the two-way solenoid valve (9). The ink return bottle (4) is equipped with a low-level float ball (15) and a high-level float ball (16). The low-level float ball (15) is used to control the opening and closing of the ink pump (21) of the ink return bottle, and the high-level float ball (16) is used to control the opening and closing of the two-way solenoid valve (10) of the ink return bottle. The ink inlet safety buffer bottle (5) is equipped with a low-level float (19) and a high-level float (20); the low-level float (19) is used to control the switch of the negative pressure system (1), and the high-level float (20) is used to control the opening and closing of the two-way solenoid valve (12). The ink return safety buffer bottle (6) is equipped with a low-level float (17) and a high-level float (18); the low-level float (17) is used to control the switch of the negative pressure system (1), and the high-level float (18) is used to control the opening and closing of the two-way solenoid valve (11).

2. A three-level ink path protection method for a 3D inkjet printing device, characterized in that, This method, based on the three-level ink path protection system of the 3D inkjet printing device as described in claim 1, includes the following steps: Step 1: When the negative pressure system (1) starts working, it generates suction on the ink remaining in the printhead, and the ink enters the ink return bottle (4); Step 2: The first layer of protection is achieved by using the low-level float ball (13) of the ink inlet bottle, the high-level float ball (14) of the ink inlet bottle, the low-level float ball (15) of the ink return bottle, and the high-level float ball (16) of the ink return bottle. Step 3: A second layer of protection is provided by using the low-level float ball (19) of the ink inlet safety buffer bottle and the low-level float ball (17) of the ink return safety buffer bottle; Step 4: A third layer of protection is provided by the high-level float ball (20) of the ink inlet safety buffer bottle and the high-level float ball (18) of the ink return safety buffer bottle.

3. The three-level ink path protection method for a 3D inkjet printing device according to claim 2, characterized in that, In step 2, the first layer of protection is achieved through the low-level float (13) of the ink inlet bottle, the high-level float (14) of the ink inlet bottle, the low-level float (15) of the ink return bottle, and the high-level float (16) of the ink return bottle, as detailed below: When the liquid level in the ink inlet bottle (3) reaches the height of the low liquid level float (13) of the ink inlet bottle or the liquid level in the return ink bottle (4) reaches the height of the low liquid level float (15) of the return ink bottle, the sensor controls the ink pump (22) of the ink inlet bottle or the ink pump (21) of the return ink bottle to close. When the liquid level in the ink inlet bottle (3) reaches the height of the high liquid level float (14) of the ink inlet bottle or the liquid level in the return ink bottle (4) reaches the height of the high liquid level float (16) of the return ink bottle, the sensor controls the two-way solenoid valve (9) of the ink inlet bottle or the two-way solenoid valve (10) of the return ink bottle to close, preventing ink from continuing to overflow and achieving the first layer of protection.

4. The three-level ink path protection method for a 3D inkjet printing device according to claim 2, characterized in that, In step 3, a second layer of protection is provided through the low-level float (19) of the ink inlet safety buffer bottle and the low-level float (17) of the ink return safety buffer bottle, as detailed below: When the malfunction continues, if closing the two-way solenoid valve (9) of the ink inlet bottle or the two-way solenoid valve (10) of the ink return bottle fails to prevent ink backflow, ink will continue to flow into the ink inlet safety buffer bottle (5) or the ink return safety buffer bottle (6). When the liquid level in the ink inlet safety buffer bottle (5) reaches the height of the low liquid level float (19) of the ink inlet safety buffer bottle or the liquid level in the ink return safety buffer bottle (6) reaches the height of the low liquid level float (17) of the ink return safety buffer bottle, the sensor controls the negative pressure system (1) to close, so that the suction force generated by the negative pressure system (1) disappears, preventing ink from backflowing further, thus achieving the second layer of protection.

5. The three-level ink path protection method for a 3D inkjet printing device according to claim 2, characterized in that, In step 4, a third layer of protection is provided through the high-level float (20) of the ink inlet safety buffer bottle and the high-level float (18) of the ink return safety buffer bottle, as detailed below: If the ink continues to overflow, when the liquid level in the ink inlet safety buffer bottle (5) reaches the height of the high liquid level float (20) of the ink inlet safety buffer bottle or the liquid level in the return ink safety buffer bottle (6) reaches the height of the high liquid level float (18) of the return ink safety buffer bottle, the sensor controls the two-way solenoid valve (12) of the ink inlet safety buffer bottle or the two-way solenoid valve (11) of the return ink safety buffer bottle to close, preventing the ink from entering the negative pressure system (1) and achieving the third layer of protection.

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