A circulating ink supply system

Abstract

The present invention belongs to the field of inkjet printing technology, and particularly relates to a circulating ink supply system, comprising a first pressure supply mechanism, a second pressure supply mechanism, and a first ink cartridge, a first ink supply pump, a second ink cartridge, a third ink cartridge, a nozzle, and the first ink cartridge, which are sequentially connected through an ink tube. Under the action of the first ink supply pump, ink can be transported from the first ink cartridge to the second ink cartridge, and then, under the action of the ink's own gravity, it can be transported to the nozzle through the third ink cartridge. In this process, gravity is used as the power for ink supply. Subsequently, under the action of the negative pressure difference between the first ink cartridge and the third ink cartridge, the ink in the nozzle can flow back to the first ink cartridge. In this process, the negative pressure difference is used as the power for the return flow. Compared with a mechanical pump, the use of gravity and negative pressure difference as power will not cause negative pressure fluctuations in the ink, thereby improving the stability of the ink during the circulation process, thereby avoiding problems such as ink breakage and ink dripping in the nozzle, and improving the printing quality.

Description

Technical Field

[0001] The present invention relates to the technical field of inkjet printing, and in particular to a circulating ink supply system. Background Art

[0002] In traditional industrial printing processes, a circulating ink supply method is often used to supply ink to the printhead. Currently, circulating ink supply is mostly powered by a mechanical pump. Since the mechanical pump will generate vibration when pumping ink, it is easy to cause negative pressure fluctuations in the entire circulation loop, resulting in problems such as ink breakage and ink dripping in the printhead, affecting printing quality.

[0003] Therefore, the above problems need to be solved urgently. Summary of the Invention

[0004] The object of the present invention is to provide a circulating ink supply system to avoid the phenomenon of unstable negative pressure when a mechanical pump pumps ink, so as to improve the printing quality.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A circulating ink supply system, comprising:

[0007] A first ink cartridge, a first ink supply pump, a second ink cartridge, a third ink cartridge, a nozzle, and the first ink cartridge are sequentially connected via ink tubes, wherein the first ink supply pump is used to transfer ink in the first ink cartridge to the second ink cartridge; the second ink cartridge is disposed above the third ink cartridge so that ink in the second ink cartridge flows from the second ink cartridge to the third ink cartridge under the action of its own gravity;

[0008] a first pressure supply mechanism, connected to the first ink cartridge and configured to apply a first negative pressure to the interior of the first ink cartridge;

[0009] The second pressure supply mechanism is connected to the third ink cartridge and is used to apply a second negative pressure to the interior of the third ink cartridge, the pressure value of which is lower than the first negative pressure, to form a negative pressure difference for returning the ink in the nozzle to the first ink cartridge.

[0010] Preferably, the circulating ink supply system further includes a degassing structure, which is disposed between the first ink supply pump and the first ink cartridge and is used to remove bubbles in the ink.

[0011] Preferably, a one-way valve is provided between the second ink cartridge and the third ink cartridge, and the one-way valve is used to limit the ink in the third ink cartridge from flowing back into the second ink cartridge.

[0012] Preferably, the circulating ink supply system further comprises:

[0013] a flow detector, disposed between the third ink cartridge and the nozzle, for detecting a flow value of ink flowing to the nozzle;

[0014] The ink path control module is electrically connected to the first pressure supply mechanism, the second pressure supply mechanism and the flow detector. The ink path control module is used to change the negative pressure difference based on the flow value to adjust the flow rate of the ink.

[0015] Preferably, a first liquid level detector electrically connected to the ink circuit control module is provided inside the first ink cartridge and the third ink cartridge, and the first liquid level detector is used to detect the liquid level inside the first ink cartridge or the third ink cartridge;

[0016] The ink circuit control module is electrically connected to the first ink supply pump, and the ink circuit control module is used to adjust the power of the first ink supply pump based on the liquid level heights of the first ink cartridge and the third ink cartridge so that the liquid level heights of the first ink cartridge and the third ink cartridge are at the same height.

[0017] Preferably, a second liquid level detector electrically connected to the ink circuit control module is provided inside the second ink cartridge, and the second liquid level detector is used to detect the minimum liquid level and the maximum liquid level inside the second ink cartridge;

[0018] The circulating ink supply system also includes:

[0019] a fourth ink cartridge, connected to the first ink cartridge;

[0020] a second ink supply pump, disposed between the fourth ink cartridge and the first ink cartridge, for delivering ink in the fourth ink cartridge to the first ink cartridge;

[0021] a first solenoid valve electrically connected to the control module, the first solenoid valve being disposed between the first ink supply pump and the second ink cartridge, the first solenoid valve being used to open and close the ink tube between the first ink supply pump and the second ink cartridge;

[0022] A second solenoid valve electrically connected to the control module, the second solenoid valve is arranged between the first ink cartridge and the second ink supply pump, and the second solenoid valve is used to open and close the ink tube between the first ink cartridge and the second ink supply pump.

[0023] Preferably, the circulating ink supply system further comprises:

[0024] A temperature detection unit is provided on the ink flow path and is used to detect the actual temperature value of the ink at different positions;

[0025] A heating portion, disposed on a flow path of the ink and used to heat the ink;

[0026] The temperature control module is electrically connected to the temperature detection unit and the heating unit, and is used to adjust the heating power of the heating unit based on the actual temperature value so as to keep the ink at a preset temperature during the flow process.

[0027] Preferably, the heating unit includes heating wires arranged on the ink tube, the first ink cartridge, the second ink cartridge, the third ink cartridge and the nozzle.

[0028] Preferably, the first pressure supply mechanism or the second pressure supply mechanism includes:

[0029] a negative pressure source, connected to the first ink cartridge or the third ink cartridge;

[0030] The buffer tank is disposed between the negative pressure source and the first ink cartridge or between the negative pressure source and the third ink cartridge to buffer the negative pressure in the ink tube.

[0031] Preferably, the first pressure supply mechanism or the second pressure supply mechanism further includes a positive pressure source connected to the buffer tank to deliver positive pressure to the first ink cartridge and the third ink cartridge.

[0032] Beneficial effects of the present invention:

[0033] The circulating ink supply system of the present invention can transfer ink from the first ink cartridge to the second ink cartridge under the action of the first ink supply pump, and then, under the action of the ink's own gravity, can be transferred to the nozzle through the third ink cartridge. In this process, gravity is used as the power of ink supply. Compared with a mechanical pump, the use of gravity as the power will not cause negative pressure fluctuations, thereby improving the stability during the ink supply process, thereby avoiding problems such as ink breakage and ink dripping in the nozzle. In addition, the provision of the second ink cartridge can prevent the negative pressure fluctuations generated by the first ink supply pump during the ink pumping process from affecting the ink between the third ink cartridge and the nozzle, further avoiding problems such as ink breakage and ink dripping in the nozzle. Subsequently, under the action of the negative pressure difference between the first and third ink cartridges, the ink in the nozzle can be returned to the first ink cartridge. In this process, the negative pressure difference is used as the power of the return flow. Compared with a mechanical pump, the use of the negative pressure difference as the power will also not cause negative pressure fluctuations in the ink, thereby improving the stability during the return flow process, further avoiding problems such as ink breakage and ink dripping in the nozzle, and improving the printing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a circulating ink supply system in an embodiment of the present invention.

[0035] In the picture:

[0036] 100, ink tube; 200, air tube;

[0037] 1. First ink cartridge; 2. First ink supply pump; 3. Second ink cartridge; 4. Third ink cartridge; 5. Printhead; 6. First pressure supply mechanism;

[0038] 7. Second pressure supply mechanism; 71. Negative pressure source; 72. Buffer tank;

[0039] 8. Degassing structure; 9. One-way valve; 10. Flow detector; 11. First liquid level detector; 12. Second liquid level detector; 13. Fourth ink cartridge; 14. Second ink supply pump; 15. First solenoid valve; 16. Second solenoid valve; 17. Temperature detection unit; 18. Heating unit; 19. Temperature control module; 20. First ink filter; 21. First ventilation pipe; 22. First air filter; 23. Second ink filter; 24. Second ventilation pipe; 25. Second air filter; 26. Third air filter. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0041] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0042] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0043] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0044] See also Figure 1 In this embodiment, a circulating ink supply system is proposed, which includes a first ink cartridge 1, a first ink supply pump 2, a second ink cartridge 3, a third ink cartridge 4, a nozzle 5 and the first ink cartridge 1 connected in sequence through an ink tube 100. The ink flow path is as follows Figure 1 As shown by the solid arrows, the first ink cartridge 1 , the second ink cartridge 3 and the third ink cartridge 4 are all ink cartridges used to contain ink in the prior art. Their specific structures are prior art and will not be described in detail here. One end of the top of the nozzle 5 has an ink inlet of the nozzle 5 connected to the third ink cartridge 4, and the other end has an ink outlet of the nozzle 5 connected to the first ink cartridge 1. The bottom of the nozzle 5 has a printing nozzle for inkjet, and the first ink supply pump 2 is used to transport the ink in the first ink cartridge 1 to the second ink cartridge 3; the second ink cartridge 3 is arranged above the third ink cartridge 4, so that the ink in the second ink cartridge 3 flows from the second ink cartridge 3 to the third ink cartridge 4 under the action of its own gravity; the circulating ink supply system also includes a first pressure supply mechanism 6 and a second pressure supply mechanism 7, the first pressure supply mechanism 6 is connected to the first ink cartridge 1, and is used to apply a first negative pressure to the interior of the first ink cartridge 1; the second pressure supply mechanism 7 is connected to the third ink cartridge 4, and is used to apply a second negative pressure to the interior of the third ink cartridge 4 with a pressure value lower than the first negative pressure, so as to form a negative pressure difference for returning the ink in the nozzle 5 to the first ink cartridge 1, and the negative pressure difference is preferably 0.6 to 1 kPa. The specific value can be adjusted according to actual printing requirements and is not specifically limited here.

[0045] It can be understood that under the action of the first ink supply pump 2, ink can be transferred from the first ink cartridge 1 to the second ink cartridge 3. Subsequently, under the action of the ink's own gravity, it can be transferred to the nozzle 5 through the third ink cartridge 4. In this process, gravity is used as the driving force for ink supply. Compared with a mechanical pump, the use of gravity as the driving force does not cause negative pressure fluctuations, thereby improving the stability of the ink supply process, thereby avoiding problems such as ink disconnection and ink dripping in the nozzle 5. In addition, the provision of the second ink cartridge 3 can prevent the negative pressure fluctuations generated by the first ink supply pump 2 during the ink pumping process from affecting the ink between the third ink cartridge 4 and the nozzle 5, further avoiding problems such as ink disconnection and ink dripping in the nozzle 5. Subsequently, under the action of the negative pressure difference between the first ink cartridge 1 and the third ink cartridge 4, the ink in the nozzle 5 can be circulated to the first ink cartridge 1. In this process, the negative pressure difference serves as the driving force for backflow. Compared with a mechanical pump, the use of the negative pressure difference as the driving force also does not cause negative pressure fluctuations in the ink, thereby improving the stability of the backflow process, further avoiding problems such as ink disconnection and ink dripping in the nozzle 5, and improving printing quality. In addition, the gravity of the ink itself and the negative pressure difference between the first ink cartridge 1 and the third ink cartridge 4 are used as power. Compared with traditional mechanical pumps, no additional noise will be generated, thereby reducing sound pollution. In order to further reduce the noise generated by the entire circulating ink supply system, the first ink supply pump 2 is preferably a peristaltic pump with lower noise in the existing technology. The specific structure of the peristaltic pump is existing technology and will not be elaborated here.

[0046] Furthermore, a one-way valve 9 is provided between the second ink cartridge 3 and the third ink cartridge 4. The one-way valve 9 is used to prevent ink in the third ink cartridge 4 from flowing back into the second ink cartridge 3. It is understood that when the second pressure supply mechanism 7 applies the second negative pressure to the third ink cartridge 4, the one-way stop valve can prevent the ink in the third ink cartridge 4 from flowing back into the second ink cartridge 3 when the negative pressure in the third ink cartridge 4 is too high, thereby ensuring stability during the ink supply process.

[0047] In addition, a first ink filter 20 is provided between the third ink cartridge 4 and the nozzle 5. The first ink filter 20 is preferably a butterfly ink filter with a specification of 10 μm in the prior art, which is used to filter impurities in the ink path to protect the nozzle 5 from being blocked by large particles.

[0048] In this embodiment, the circulating ink supply system further includes a degassing structure 8, which is disposed between the first ink supply pump 2 and the first ink cartridge 1. Degassing structure 8 is used to remove bubbles from the ink. As will be appreciated, during the ink transfer process from the first ink cartridge 1 to the second ink cartridge 3, bubbles trapped in the ink are removed by the degassing structure 8, thereby preventing them from being ejected from the printhead 5 along with the ink, further improving print quality.

[0049] The degassing structure 8 is preferably a columnar degassing lung in the prior art. The ink inlet of the degassing lung is connected to the ink outlet of the first ink cartridge 1 through the ink tube 100, and the ink outlet of the degassing lung is connected to the ink inlet of the second ink cartridge 3. The air inlet of the degassing lung is connected to the first pressure supply mechanism 6 through the trachea 200. The first pressure supply mechanism 6 can apply negative pressure to the degassing lung. The gas path is as follows: Figure 1 As shown by the dashed arrow in the middle, the pressure inside the degassing lung can be reduced, making it easier for gas to escape from the ink, thereby achieving bubble removal. In some other feasible embodiments, the degassing structure 8 can also be an ultrasonic degasser in the prior art. Its specific structure is prior art and will not be described in detail here.

[0050] Furthermore, the ink inlet of the second ink cartridge 3 is located at the top of the second ink cartridge 3 , and a first ventilation tube 21 is also provided at the top of the second ink cartridge 3 . A first air filter 22 is provided on the first ventilation tube 21 . It is understood that as ink enters the second ink cartridge 3 through the ink inlet, the height difference allows for the precipitation of residual bubbles in the ink, which are then discharged from the second ink cartridge 3 through the first ventilation tube 21 , further improving the degassing effect of the ink. Furthermore, the provision of the first ventilation tube 21 maintains a stable air pressure within the second ink cartridge 3 , ensuring stability during ink delivery. The first air filter 22 prevents external impurities from entering the interior of the second ink cartridge 3 through the first ventilation tube 21 .

[0051] In this embodiment, the circulating ink supply system also includes a flow detector 10 and an ink path control module. The flow detector 10 is arranged between the third ink cartridge 4 and the nozzle 5, and is used to detect the flow value of the ink flowing to the nozzle 5; the ink path control module is electrically connected to the first pressure supply mechanism 6, the second pressure supply mechanism 7 and the flow detector 10, and the ink path control module is used to change the negative pressure difference based on the flow value to adjust the flow rate of the ink. It can be understood that, according to actual printing needs, a flow threshold is set, and the actual flow value flowing to the nozzle 5 is detected by the flow detector 10. If the actual flow value is lower than the flow threshold, the ink path control module sends a signal to the first pressure supply mechanism 6 and the second pressure supply mechanism 7, and increases the negative pressure difference by adjusting the first negative pressure and the second negative pressure values, thereby increasing the power of the reflux and thus increasing the flow rate of the ink. Conversely, if the actual flow value is higher than the flow threshold, the ink path control module sends a signal to the first pressure supply mechanism 6 and the second pressure supply mechanism 7, and reduces the negative pressure difference by adjusting the first negative pressure and the second negative pressure values, thereby reducing the power of the reflux and thus reducing the flow rate of the ink. The ink path control module is preferably a PLC controller in the prior art, and the flow detector 10 is a caliper-type flow detector in the prior art.

[0052] Furthermore, the first ink cartridge 1 and the third ink cartridge 4 are both provided with a first liquid level detector 11 electrically connected to the ink circuit control module, and the first liquid level detector 11 is used to detect the liquid level height inside the first ink cartridge 1 or the third ink cartridge 4; the ink circuit control module is electrically connected to the first ink supply pump 2, and the ink circuit control module is used to adjust the power of the first ink supply pump 2 based on the liquid level height of the first ink cartridge 1 and the third ink cartridge 4 so that the liquid level height of the first ink cartridge 1 and the third ink cartridge 4 are at the same height. It can be understood that the first ink cartridge 1 and the second ink cartridge 3 form a communicating vessel structure through the ink tube 100 and the nozzle 5. Based on the characteristics of the communicating vessel, the ink inside the first ink cartridge 1 and the second ink cartridge 3 can be maintained at the same horizontal height under the action of gravity, pressure, etc., which can easily affect the backflow of ink. Therefore, in this embodiment, when the first ink supply pump 2 is pumping ink, the first liquid level detector 11 can detect the liquid level height inside the first ink cartridge 1 and the second ink cartridge 3. By adjusting the power of the first ink supply pump 2, the liquid level height inside the first ink cartridge 1 and the second ink cartridge 3 can be kept consistent, so as to further improve the stability of the circulating ink supply system and improve the ink supply efficiency.

[0053] Furthermore, a second liquid level detector 12 electrically connected to the ink circuit control module is provided inside the second ink cartridge 3, and the second liquid level detector 12 is used to detect the minimum liquid level height and the maximum liquid level height inside the second ink cartridge 3; the circulating ink supply system also includes a fourth ink cartridge 13, a second ink supply pump 14, a first solenoid valve 15 and a second solenoid valve 16, and the fourth ink cartridge 13 is connected to the first ink cartridge 1; the second ink supply pump 14 is provided between the fourth ink cartridge 13 and the first ink cartridge 1, and is used to transport the ink in the fourth ink cartridge 13 to the first ink cartridge 1; the first solenoid valve 15 is electrically connected to the control module, the first solenoid valve 15 is provided between the first ink supply pump 2 and the second ink cartridge 3, and the first solenoid valve 15 is used to open and close the ink tube 100 between the first ink supply pump 2 and the second ink cartridge 3; the second solenoid valve 16 is electrically connected to the control module, the second solenoid valve 16 is provided between the first ink cartridge 1 and the second ink supply pump 14, and the second solenoid valve 16 is used to open and close the ink tube 100 between the first ink cartridge 1 and the second ink supply pump 14. It can be understood that during the ink supply process, the ink inside the first ink cartridge 1 comes from two sources, one is the ink supplied to the first ink cartridge 1 by the fourth ink cartridge 13, and the other is the ink flowing back to the first ink cartridge 1 through the negative pressure difference. In order to ensure that the ink inside the first ink cartridge 1 and the third ink cartridge 4 are at the same level, the ink needs to be transported from the first ink cartridge 1 to the second ink cartridge 3 through the first ink supply pump 2, and the second ink cartridge 3 is temporarily used as a buffer. When the second liquid level detector 12 detects that the liquid level in the second ink cartridge 3 has reached the maximum liquid level, it sends a signal to the ink path control module, and the ink path control module The module controls the first and second solenoid valves 15 and 16 to disconnect the ink tube 100. This means that the fourth ink cartridge 13 stops supplying ink to the first ink cartridge 1, and the first ink cartridge 1 stops supplying ink to the second ink cartridge 3. Under the influence of gravity, the ink in the second ink cartridge 3 flows into the third ink cartridge 4. The negative pressure differential allows the ink in the printhead 5 to circulate to the first ink cartridge 1. The first liquid level detector 11 and the ink path control module coordinate to maintain the liquid levels in the first and third ink cartridges 4 at the same level, ensuring the stability of the circulating ink supply system. Furthermore, gravity and pressure differentials allow the ink to be transported. During this process, the first and second ink supply pumps 2 and 14 can be temporarily shut down, effectively alleviating the problem of the first and second ink supply pumps 2 and 14 overheating and burning due to prolonged operation. This significantly reduces material damage and saves material costs. In addition, in this embodiment, the second ink supply pump 14 is preferably a peristaltic pump with relatively low noise in the prior art, so as to further reduce the noise of the entire circulating ink supply system.

[0054] In addition, a second ink filter 23 is arranged between the fourth ink cartridge 13 and the second ink supply pump 14, and a third ink filter 26 is also arranged on the ink tube 100 connected to the ink inlet of the fourth ink cartridge 13. The second ink filter 23 and the third ink filter 26 are preferably butterfly-shaped ink filters with a specification of 10um in the prior art to prevent impurities and other particulate matter from entering the circulating ink path.

[0055] It is worth noting that the ink inlet of the fourth ink cartridge 13 is located at the top of the fourth ink cartridge 13 and is connected to the external ink supply mechanism via the ink tube 100. A second ventilation tube 24 is also provided at the top of the fourth ink cartridge 13, and a second air filter 25 is installed on the second ventilation tube 24. It is understood that the external ink supply mechanism supplies ink to the fourth ink cartridge 13 through the ink tube 100. Due to the height difference, bubbles in the ink are separated and then discharged from the fourth ink cartridge 13 through the second ventilation tube 24, further improving the degassing effect of the ink. In addition, the provision of the second ventilation tube 24 maintains a stable air pressure inside the fourth ink cartridge 13, ensuring the stability of the ink during the delivery process. The second air filter 25 prevents external impurities from entering the interior of the second ink cartridge 3 through the second ventilation tube 24. The volume of the fourth ink cartridge 13 is preferably 500ml, and that of the first ink cartridge 1, the second ink cartridge 3, and the third ink cartridge 4 are all 150ml. This configuration ensures long-term printing without the need for ink refills.

[0056] In this embodiment, the specific structures of the first pressure supply mechanism 6 and the second pressure supply mechanism 7 are identical. The second pressure supply mechanism 7 is used as an example for explanation. The second pressure supply mechanism 7 includes a negative pressure source 71 and a buffer tank 72. The negative pressure source 71 is in communication with the first ink cartridge 1 or the third ink cartridge 4. The buffer tank 72 is disposed between the negative pressure source 71 and the first ink cartridge 1 or between the negative pressure source 71 and the third ink cartridge 4 to buffer the negative pressure within the ink tube 100. It will be appreciated that, when supplying negative pressure to the first ink cartridge 1 or the second ink cartridge 3, the provision of the buffer tank 72 can reduce the impact of reduced pressure in the first ink cartridge 1 or the second ink cartridge 3 on the ink path, thereby preventing negative pressure fluctuations within the ink tube 100 and further improving the stability of the ink path.

[0057] During the printing process, if bubbles still remain inside the nozzle 5, the printing effect will be affected. Therefore, in this embodiment, the second pressure supply mechanism 7 also includes a positive pressure source, which is connected to the buffer tank 72 to supply positive pressure to the first ink cartridge 1 and the third ink cartridge 4. It can be understood that the positive pressure supplied to the first ink cartridge 1 and the third ink cartridge 4 by the positive pressure source can discharge the ink inside the nozzle 5 through the print nozzle under the action of the positive pressure, and printing can be resumed after the bubbles are discharged.

[0058] Conventional industrial printheads 5 typically only support inks with viscosities between 5 and 12 centipoise (cp) at room temperature, with some models only supporting up to 30 cp. Solvents with high viscosities exceeding 30 cp at room temperature must be heated to approximately 60 to 80°C during use. To this end, the circulating ink supply system in this embodiment also includes a temperature detection unit 17, a heating unit 18, and a temperature control module 19 to achieve comprehensive thermal insulation along the flow path, enabling the circulating ink supply system to transport solvents of varying viscosities.

[0059] Specifically, the temperature detection unit 17 is arranged on the flow path of the ink and is used to detect the actual temperature value of the ink at different positions; the heating unit 18 is arranged on the flow path of the ink and is used to heat the ink; the temperature control module 19 is electrically connected to the temperature detection unit 17 and the heating unit 18, and is used to adjust the heating power of the heating unit 18 based on the actual temperature value so that the ink is maintained at a preset temperature during the flow process. It can be understood that the above-mentioned flow path means that the ink flows from the fourth ink cartridge 13 to the first ink cartridge 1 through the ink tube 100, flows from the first ink cartridge 1 to the second ink cartridge 3 through the ink tube 100, flows from the second ink cartridge 3 to the third ink cartridge 4 through the ink tube 100, and flows from the third ink cartridge 4 to the nozzle 5 through the ink tube 100. Part of the ink is ejected from the print nozzle for printing, and the remaining ink flows back to the first ink cartridge 1 through the ink tube 100. The ink tube 100, the first ink cartridge 1, the second ink cartridge 3, the third ink cartridge 4 and the nozzle 5 are all provided with a heating part 18. The first ink cartridge 1, the second ink cartridge 3, the third ink cartridge 4 and the nozzle 5 are all provided with a temperature detection part 17. With such a configuration, the temperature detection part 17 can detect the temperature of the ink at different positions and transmit the detection result to the temperature control module 19. Based on the detection result, the temperature control module 19 can control the heating part 18 to heat or stop heating the ink. The temperature control module 19 is preferably a temperature control board in the prior art to achieve precise temperature control.

[0060] Specifically in this embodiment, for the ink cartridges (including the first ink cartridge 1, the second ink cartridge 3, the third ink cartridge 4 and the fourth ink cartridge 13), the ink cartridges are preferably black light-proof ink cartridges with anodized aluminum, and the heating part 18 includes a heating wire and a substrate. A substrate is provided on each side wall of the ink cartridge, and the heating wire is embedded in the interior of the substrate. The ink inside the ink cartridge is heated by heat conduction through the substrate and the side wall of the ink cartridge. The heating wire is preferably a nickel-chromium alloy heating wire, and the substrate is preferably a ceramic substrate. Such a setting can ensure the stability of the temperature during the transmission process.

[0061] The temperature detection unit 17 includes a temperature sensor, a detection end of which is clamped between the substrate and the side wall of the ink cartridge to detect the temperature of the ink inside the ink cartridge.

[0062] The ink tube 100 is preferably a high-temperature resistant black Teflon ink tube 100 to prevent damage from high temperatures and improve safety. The heating unit 18 includes a heating wire and insulation foam. The heating wire is wrapped around the outside of the ink tube 100 and is wrapped with insulation foam to ensure heating performance. The heating wire is preferably a nickel-chromium alloy heating wire, and the insulation foam is preferably an insulating and high-temperature resistant aerogel foam.

[0063] For the nozzle 5, the heating part 18 includes a heating wire and a substrate. A substrate is provided on each side wall of the nozzle 5, and the heating wire is embedded in the interior of the substrate. The ink inside the nozzle 5 is heated by heat conduction of the substrate and the side wall of the nozzle 5, so that there is no need to integrate a heating structure inside the nozzle 5. Among them, the heating wire is preferably a nickel-chromium alloy heating wire, and the substrate is preferably a ceramic substrate. Such an arrangement can ensure the stability of the temperature during the transmission process.

[0064] The temperature detection unit 17 includes two temperature sensors, one of which is arranged on the ink tube 100 connected to the ink inlet of the nozzle 5, and the other is arranged on the ink tube 100 at the ink outlet of the nozzle 5. The temperature of the ink inside the nozzle 5 can be obtained by the difference between the two temperature sensors, so that the heating unit 18 can heat the nozzle 5.

[0065] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A circulating ink supply system, characterized in that: include: A first ink cartridge (1), a first ink supply pump (2), a second ink cartridge (3), a third ink cartridge (4), a nozzle (5), and the first ink cartridge (1) are sequentially connected via an ink tube (100); the first ink supply pump (2) is used to transport ink in the first ink cartridge (1) to the second ink cartridge (3); the second ink cartridge (3) is arranged above the third ink cartridge (4), so that the ink in the second ink cartridge (3) flows from the second ink cartridge (3) to the third ink cartridge (4) under the action of its own gravity; a first pressure supply mechanism (6), connected to the first ink cartridge (1) and used for applying a first negative pressure to the interior of the first ink cartridge (1); a second pressure supply mechanism (7) connected to the third ink cartridge (4) and used for applying a second negative pressure having a pressure value lower than the first negative pressure to the interior of the third ink cartridge (4), so as to form a negative pressure difference for causing the ink in the nozzle (5) to flow back to the first ink cartridge (1); a flow rate detector (10), disposed between the third ink cartridge (4) and the nozzle (5), for detecting a flow rate value of ink flowing to the nozzle (5); an ink circuit control module electrically connected to the first pressure supply mechanism (6), the second pressure supply mechanism (7) and the flow detector (10), the ink circuit control module being used to change the negative pressure difference based on the flow value to adjust the flow rate of the ink; A first liquid level detector (11) electrically connected to the ink path control module is provided inside the first ink cartridge (1) and the third ink cartridge (4), and the first liquid level detector (11) is used to detect the liquid level inside the first ink cartridge (1) or the third ink cartridge (4); The ink circuit control module is electrically connected to the first ink supply pump (2), and the ink circuit control module is used to adjust the power of the first ink supply pump (2) based on the liquid level heights of the first ink cartridge (1) and the third ink cartridge (4), so that the liquid levels of the first ink cartridge (1) and the third ink cartridge (4) are at the same height; A second liquid level detector (12) electrically connected to the ink path control module is provided inside the second ink cartridge (3), and the second liquid level detector (12) is used to detect the minimum liquid level and the maximum liquid level inside the second ink cartridge (3); The circulating ink supply system also includes: a fourth ink cartridge (13), connected to the first ink cartridge (1); The second ink supply pump (14) is arranged between the fourth ink cartridge (13) and the first ink cartridge (1) and is used for delivering the ink in the fourth ink cartridge (13) to the first ink cartridge (1).

2. The circulating ink supply system according to claim 1, characterized in that: The circulating ink supply system further comprises a degassing structure (8), which is arranged between the first ink supply pump (2) and the first ink cartridge (1), and is used to remove bubbles in the ink.

3. The circulating ink supply system according to claim 1, characterized in that: A one-way valve (9) is provided between the second ink cartridge (3) and the third ink cartridge (4), and the one-way valve (9) is used to limit the ink in the third ink cartridge (4) from flowing back to the second ink cartridge (3).

4. The circulating ink supply system according to claim 1, characterized in that: The circulating ink supply system also includes: a first solenoid valve (15) electrically connected to the control module, the first solenoid valve (15) being disposed between the first ink supply pump (2) and the second ink cartridge (3), the first solenoid valve (15) being used to open and close the ink tube (100) between the first ink supply pump (2) and the second ink cartridge (3); A second solenoid valve (16) electrically connected to the control module, wherein the second solenoid valve (16) is arranged between the first ink cartridge (1) and the second ink supply pump (14), and the second solenoid valve (16) is used to open and close the ink tube (100) between the first ink cartridge (1) and the second ink supply pump (14).

5. The circulating ink supply system according to claim 1, characterized in that: The circulating ink supply system also includes: A temperature detection unit (17) is provided on the flow path of the ink and is used to detect actual temperature values ​​of the ink at different positions; A heating portion (18) is provided on the flow path of the ink and is used to heat the ink; A temperature control module (19) is electrically connected to the temperature detection unit (17) and the heating unit (18), and is used to adjust the heating power of the heating unit (18) based on the actual temperature value so that the ink is maintained at a preset temperature during the flow process.

6. The circulating ink supply system according to claim 5, characterized in that: The heating portion (18) includes a heating wire arranged on the ink tube (100), the first ink cartridge (1), the second ink cartridge (3), the third ink cartridge (4) and the nozzle (5).

7. The circulating ink supply system according to claim 1, characterized in that: The first pressure supply mechanism (6) or the second pressure supply mechanism (7) comprises: a negative pressure source (71) in communication with the first ink cartridge (1) or the third ink cartridge (4); A buffer tank (72) is provided between the negative pressure source (71) and the first ink cartridge (1) or between the negative pressure source (71) and the third ink cartridge (4) to buffer the negative pressure in the ink tube (100).

8. The circulating ink supply system according to claim 7, characterized in that: The first pressure supply mechanism (6) or the second pressure supply mechanism (7) further comprises a positive pressure source, which is in communication with the buffer tank (72) so as to deliver positive pressure to the first ink cartridge (1) and the third ink cartridge (4).

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