An ink supply system

Abstract

The application discloses a kind of ink supply systems, it is related to digital printing technical field to solve how to reduce the quantity of filter and degassing assembly in ink supply system, to reduce the cost of ink supply system Problem.The ink supply system includes first ink supply assembly, two ends of secondary ink cartridge are respectively communicated with first ink supply assembly and degassing assembly, two ends of first filter are respectively communicated with degassing assembly and main ink pipe, multiple ink-jet heads are simultaneously communicated with main ink pipe by multiple ink delivery tubes, the lowest point of secondary ink cartridge is higher than the highest point of any ink-jet head, the number of degassing assembly and the number of first filter are less than the total number of ink-jet head, liquid level sensor is located in secondary ink cartridge.The lowest point of secondary ink cartridge and the highest point of ink-jet head have height difference, wherein the sum of pressure required for ink-jet head and along loss pressure, along loss pressure is the pressure lost in the process of ink flowing from secondary ink cartridge to ink-jet head, is ink density, is acceleration of gravity.

Description

Technical Field

[0001] This invention relates to the field of digital printing technology, and more particularly to an ink supply system. Background Technology

[0002] The ink supply system of a digital inkjet printer is an integrated fluid control unit that connects ink storage, delivery, voltage stabilization, circulation, filtration, temperature control, and cleaning and recycling. Its core function is to stably, continuously, and without sedimentation or dripping deliver ink to the printhead. It directly determines whether the printing process will experience ink interruption, printhead clogging, ink splatter, or color difference, and is one of the core subsystems of industrial digital printing equipment.

[0003] Currently, in the digital inkjet printing industry, ink supply systems typically include a main ink tank, secondary ink cartridges, multiple printheads, multiple filters, and multiple degassing components. The main ink tank is connected to the secondary ink cartridges, supplying ink to them. Each printhead is connected to a secondary ink cartridge via a corresponding ink supply tube, and each printhead and secondary ink cartridge is connected to a filter and a degassing component. Existing ink supply systems have numerous branches and components, and the high cost of filters and degassing components contributes to the overall high cost of the ink supply system.

[0004] Therefore, how to reduce the number of filters and degassing components in the ink supply system to lower the cost of the ink supply system has become a pressing technical problem for the industry. Summary of the Invention

[0005] The purpose of this invention is to provide an ink supply system that reduces the number of filters and degassing components in the ink supply system, thereby reducing the cost of the ink supply system.

[0006] To achieve the above objectives, the present invention provides an ink supply system. This system includes a first ink supply assembly, a secondary ink cartridge, a degassing assembly, a first filter, a main ink tube, printheads, and a level sensor. One end of the secondary ink cartridge is connected to the first ink supply assembly, which supplies ink to the secondary ink cartridge. One end of the degassing assembly is connected to the other end of the secondary ink cartridge, one end of the first filter is connected to the other end of the degassing assembly, and one end of the main ink tube is connected to the other end of the first filter. Multiple printheads are simultaneously connected to the main ink tube through multiple ink supply tubes. The lowest point of the secondary ink cartridge is higher than the highest point of any printhead. The main ink tube supplies ink to the printheads through the ink supply tubes. The number of degassing assemblies and the number of first filters are both less than the total number of printheads. The level sensor is located inside the secondary ink cartridge. There is a height difference between the lowest point of the secondary ink cartridge and the highest point of the printhead. , .in, This is the sum of the pressure required by the printhead and the pressure lost along the flow path. The pressure lost along the flow path is the pressure lost by the ink as it flows from the secondary ink cartridge to the printhead. For ink density, This is the acceleration due to gravity.

[0007] Compared with existing technologies, the advantages of this application are as follows: a main ink tube is added between the secondary ink cartridge and multiple printheads; a degassing component and a first filter are installed on the ink supply line from the secondary ink cartridge to the main ink tube; and the number of degassing components and the number of first filters are both less than the total number of printheads. Before the ink enters the main ink tube from the secondary ink cartridge, the degassing component and the first filter uniformly degas and filter impurities from the ink. Compared to the secondary ink cartridge being directly connected to multiple printheads, and each branch requiring expensive filters and degassing components before the ink enters the printhead, this application uniformly treats the ink by installing a degassing component and a first filter before the main ink tube, which reduces the number of filters and degassing components in the ink supply system, thereby reducing the cost of the ink supply system. In particular, when the ink supply system of this application includes only one degassing component and one first filter, the cost of the ink supply system can be significantly reduced.

[0008] In one implementation, the main ink tube is positioned above the highest point of any printhead, and below the lowest point of the secondary ink cartridge.

[0009] In one implementation, the first ink supply component includes: First ink supply tank; The first ink supply pump, one end of which is connected to the first ink supply tank; The second filter is connected at both ends to the other end of the first ink pump and the secondary ink cartridge, respectively.

[0010] In one implementation, the ink supply system further includes a controller and a second ink supply component; The second ink supply assembly includes: The second ink supply tank has a highest point that is lower than the lowest point of the secondary ink cartridge; one end of the second ink supply tank is connected to the first ink supply pump, and the first ink supply assembly is used to supply ink to the second ink supply tank. The second ink supply pump has two ends connected to the other end of the second ink supply tank and the second filter, respectively. The float level switch is located inside the second ink supply tank; the float level switch is connected to the controller.

[0011] In one implementation, the float level switch includes three floats, which are spaced apart along the height direction of the second ink supply tank. The three floats are defined as a first float, a second float, and a third float along the height direction of the second ink supply tank. The third float is close to the bottom of the second ink supply tank and is spaced apart from the bottom of the second ink supply tank. The controller controls the first ink supply assembly to supply ink to the second ink tank or stop ink supply based on the signal from the second float. The controller controls the replacement of the first ink supply unit based on the signal from the third float.

[0012] In one implementation, when the first ink supply component is replaced, the second ink supply tank supplies ink to the secondary ink cartridge for a longer period than the replacement time of the first ink supply component.

[0013] In one implementation, the top of the secondary ink cartridge has a through hole; The through-hole is open to the atmosphere; or, the secondary ink cartridge is connected to the negative pressure control component through the through-hole; or, the secondary ink cartridge is connected to the positive pressure control component through the through-hole.

[0014] In one implementation, the through-hole is connected to the atmosphere, and the ink supply system also includes an ink sac. Each ink cartridge is located at the ink inlet of each printhead, and the ink inlet of each ink cartridge is connected to the main ink tube through a corresponding ink supply tube.

[0015] In one implementation, multiple printheads are arranged in an array; or, along the length of the main ink tube, multiple printheads are distributed at equal intervals.

[0016] In one implementation, all ink supply tubes connecting the printhead and the main ink tube are of equal length. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of an ink supply system according to an embodiment of the present invention; Figure label: 1-First ink supply assembly, 10-First ink tank, 11-First ink pump, 12-Second filter, 2-Secondary ink cartridge, 3-Degassing assembly, 4-First filter, 5-Main ink tube, 6-Printhead, 7-Level sensor, 8-Ink supply tube, 9-Second ink supply assembly, 90-Second ink tank, 91-Second ink pump, 92-Float level switch, 920-First float, 921-Second float, 922-Third float; 93-Through hole, 94-Ink sac. Detailed Implementation

[0018] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0019] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0020] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0021] In the background section, within the digital inkjet printing machine industry, the ink supply system can be a dual negative pressure internal and external circulation ink supply system. This system typically includes: dual ink cartridges, dual negative pressure proportional valves, a circulation pump, multi-stage filtration, temperature control, and a defoaming module. While this system offers numerous advantages—fewer printhead clogging, high ink utilization, and long printhead life—making it suitable for large-scale continuous production in factories, its numerous branches, components, and complex electrical control result in high initial hardware costs. For users with limited budgets, this translates to relatively high upfront costs.

[0022] To address the aforementioned technical problems, this invention provides an ink supply system. This ink supply system can be applied to large-scale digital printing production of garments, home textiles, flags, and other products, and is suitable for industrial-grade printers that require continuous operation for extended periods.

[0023] See Figure 1The ink supply system includes a first ink supply assembly 1, a secondary ink cartridge 2, a degassing assembly 3, a first filter 4, a main ink tube 5, printheads 6, and a level sensor 7. One end of the secondary ink cartridge 2 is connected to the first ink supply assembly 1, which supplies ink to the secondary ink cartridge 2. One end of the degassing assembly 3 is connected to the other end of the secondary ink cartridge 2, one end of the first filter 4 is connected to the other end of the degassing assembly 3, and one end of the main ink tube 5 is connected to the other end of the first filter 4. The secondary ink cartridge 2 supplies ink to the main ink tube 5. Multiple printheads 6 are simultaneously connected to the main ink tube 5 through multiple ink supply tubes 8, and the nozzles of the printheads 6 are open to the atmosphere. The lowest point of the secondary ink cartridge 2 is higher than the highest point of any printhead 6. The main ink tube 5 supplies ink to the printheads 6 through the ink supply tubes 8. The number of degassing assemblies 3 and the number of first filters 4 are both less than the total number of printheads 6. The level sensor 7 is located inside the secondary ink cartridge 2. There is a height difference between the lowest point of the secondary ink cartridge 2 and the highest point of the printhead 6. , .in, This is the sum of the pressure required for printhead 6 and the pressure lost along the flow path. The pressure lost along the flow path is the pressure lost by the ink as it flows from the secondary ink cartridge 2 to the printhead 6. For ink density, This is the acceleration due to gravity.

[0024] See Figure 1 Compared with the prior art, the beneficial effects of this application are as follows: a main ink tube 5 is added between the secondary ink cartridge 2 and multiple printheads 6; a degassing component 3 and a first filter 4 are installed on the ink supply pipe 8 from the secondary ink cartridge 2 to the main ink tube 5, and the number of degassing components 3 and the number of first filters 4 are both less than the total number of printheads 6. Before the ink enters the main ink tube 5 from the secondary ink cartridge 2, the degassing component 3 and the first filter 4 are used to uniformly degas and filter impurities from the ink. Compared with the secondary ink cartridge 2 being directly connected to multiple printheads 6, and each branch requiring expensive filters and degassing components 3 before the ink enters the printheads 6, this application sets up degassing components 3 and first filters 4 before the main ink tube 5 to uniformly process the ink, which can reduce the number of filters and degassing components 3 in the ink supply system, thereby reducing the cost of the ink supply system.

[0025] In this embodiment, the ink supply system includes only a degassing component 3 and a first filter 4, which can significantly reduce the cost of the ink supply system.

[0026] For details regarding the specific structure of the secondary ink cartridge 2, the degassing component 3, and the first filter 4, please refer to the existing technology; no specific limitations will be made here.

[0027] See Figure 1Because the ink has a strong impact force and is accompanied by air bubbles after passing through the first ink supply component 1, it will affect the stability of the entire ink supply system and the printing effect of the printhead 6. The degassing component 3 can remove the air bubbles and ensure the printing quality.

[0028] See Figure 1 The first filter 4 can filter impurities in the ink, prevent clogging of the main ink tube 5 and the printhead 6, ensure normal printing and ensure print quality.

[0029] The aforementioned liquid level sensor 7 can be a float level switch, which may include two or three floats.

[0030] See Figure 1 In actual use, ink from the first ink supply assembly 1 enters the secondary ink cartridge 2. When the ink level in the secondary ink cartridge 2 rises to the high level and is detected by the float level switch (i.e., the level sensor 7), the first ink supply assembly 1 stops supplying ink to the secondary ink cartridge 2. As printing continues, the ink level in the secondary ink cartridge 2 gradually decreases. When the ink level in the secondary ink cartridge 2 drops to the low level and is detected by the float level switch, the first ink supply assembly 1 is activated, supplying ink to the secondary ink cartridge 2. At this time, the ink level in the secondary ink cartridge 2 remains within a constant range.

[0031] As one possible implementation, see Figure 1 The main ink tube 5 can be a relatively large ink supply tube, used to supply ink from the secondary ink cartridge 2 to multiple printheads 6 connected to it. The specific size, shape, and material of the main ink tube 5 can be set according to actual conditions and are not specifically limited here. For example, the main ink tube 5 can be a cuboid or a cylindrical main ink tube.

[0032] As one possible implementation, see Figure 1 Multiple nozzles are arranged in an array, such as a rectangular array or a circular array.

[0033] As another possible implementation, see Figure 1 Along the length direction A of the main ink tube 5, multiple nozzles 6 are distributed at equal intervals.

[0034] As one possible implementation, see Figure 1 All ink supply tubes 8 connecting the printhead 6 and the main ink tube 5 are of equal or substantially equal length. This allows for equal pressure loss at multiple printheads 6, ensuring uniform ink ejection and thus guaranteeing print quality.

[0035] In one alternative approach, see Figure 1The ink supply tube 8, which connects the printhead 6 and the main ink tube 5, extends in a straight line along the direction of gravity, meaning that the ink supply tube 8 is not distributed in a curved or bent manner.

[0036] As one possible implementation, see Figure 1 The main ink tube 5 is positioned higher than the highest point of any printhead 6, and lower than the lowest point of the secondary ink cartridge 2. Combining this with the preceding description, the lowest point of the secondary ink cartridge 2 is higher than the highest point of any printhead 6, and... .

[0037] The ink from the secondary ink cartridge 2 to the printhead 6 flows naturally downwards under atmospheric pressure and liquid column pressure difference, and the pressure is sufficient to overcome the resistance of the first filter 4 and the degassing component 3.

[0038] As one possible implementation, see Figure 1 The first ink supply assembly 1 includes: a first ink supply tank 10, a first ink supply pump 11, and a second filter 12. One end of the first ink supply pump 11 is connected to the first ink supply tank 10, and both ends of the second filter 12 are connected to the other end of the first ink supply pump 11 and the secondary ink cartridge 2, respectively.

[0039] As another possible implementation, the first ink supply assembly 1 includes: a first ink tank 10, a one-way valve, and a second filter 12. One end of the one-way valve is connected to the first ink tank 10, and both ends of the second filter 12 are connected to the other end of the one-way valve and the secondary ink cartridge 2, respectively.

[0040] As for the material and capacity of the first ink supply tank 10, they can be set according to actual needs, and no specific limitations are made here.

[0041] As one possible implementation, see Figure 1 The ink supply system also includes a controller ( Figure 1 (Not shown in the image) and the second ink supply assembly 9. At this time, the first ink supply assembly 1 supplies ink to the second ink supply assembly 9, and the second ink supply assembly 9 supplies ink to the secondary ink cartridge 2. The liquid level sensor 7 may or may not be connected to the controller. In some embodiments, the liquid level sensor 7 is electrically or communicatively connected to the controller.

[0042] As one possible implementation, see Figure 1 The second ink supply assembly 9 includes a second ink tank 90, a second ink pump 91, and a float level switch 92. The highest point of the second ink tank 90 is lower than the lowest point of the secondary ink cartridge 2, and one end of the second ink tank 90 is connected to the first ink pump 11. The two ends of the second ink pump 91 are respectively connected to the other end of the second ink tank 90 and the second filter 12. The float level switch 92 is located inside the second ink tank 90 and is connected to a controller (e.g., a communication connection or an electrical connection).

[0043] In actual use, the first ink supply pump 11 draws ink from the first ink supply tank 10 and supplies it to the second ink supply tank 90. ​​The second ink supply tank 90 is equipped with a float level switch 92 to ensure that the ink level in the second ink supply tank 90 remains within a constant range. Next, the second ink supply pump 91 draws ink from the second ink supply tank 90, which is then filtered by the second filter 12 before being supplied to the secondary ink cartridge 2.

[0044] In one alternative approach, see Figure 1 The float level switch 92 includes three floats, spaced apart along the height direction B of the second ink supply tank 90. ​​Along the height direction of the second ink supply tank 90, the three floats are sequentially defined as a first float 920, a second float 921, and a third float 922. The third float 922 is located near the bottom of the second ink supply tank 90, and is spaced apart from the bottom of the second ink supply tank 90.

[0045] The controller controls the first ink supply assembly 1 to supply ink to the second ink tank 90 or to stop ink supply based on the signal from the second float 921. The controller controls the replacement of the first ink supply assembly 1 based on the signal from the third float 922.

[0046] In actual use, as printing continues, the ink level in the second ink supply tank 90 gradually decreases. When the ink level in the second ink supply tank 90 drops to the second float 921, triggering the float level switch 92, the controller activates the first ink supply pump 11. At this time, the first ink supply pump 11 draws ink from the first ink supply tank 10 and supplies it to the second ink supply tank 90. ​​When the ink level in the second ink supply tank 90 rises to the second float 921, triggering the float level switch 92, the controller deactivates the first ink supply pump 11, and the first ink supply tank 10 stops supplying ink to the second ink supply tank 90.

[0047] During the process of supplying ink to the second ink tank 90 using the first ink supply assembly 1, the amount of ink stored in the first ink tank 10, which is included in the first ink supply assembly 1, gradually decreases. If, during the process of supplying ink to the second ink tank 90 using the first ink tank 10, the ink level in the second ink tank 90 drops to the third float 922 due to the synchronous printing, and the float level switch 92 detects this, it indicates that the ink level in the first ink tank 10 is zero or almost zero, and the first ink tank 10 cannot supply ink to the second ink tank 90. ​​However, the ink level in the second ink tank 90 continues to decrease due to the printing process. At this time, the controller receives the signal from the third float 922 and issues a prompt (e.g., a text prompt, an audio prompt, or a light prompt). The operator, a robotic arm, or a robot removes the empty first ink supply assembly 1 and replaces it with a first ink supply assembly 1 that meets the ink level requirements.

[0048] In this application, the ink capacity of the second ink supply tank 90 is much greater than the amount of ink consumed during printing when the first ink supply tank 10 is replaced. Therefore, even if the first ink supply component 1 does not supply ink to the second ink supply tank 90 during the time the first ink supply component 1 is replaced, the ink in the second ink supply tank 90 alone can supply ink to the secondary ink cartridge 2, ensuring continuous ink supply to the entire system and smooth printing. This structural design is well-suited for industrial printers with high ink consumption, expanding the applicability of the ink supply system. That is, when replacing the first ink supply component 1, the time the second ink supply tank 90 supplies ink to the secondary ink cartridge 2 is longer than the replacement time of the first ink supply component 1.

[0049] In some embodiments, when the first ink supply assembly 1 is replaced, the second ink supply tank 90 supplies ink to the secondary ink cartridge 2 for at least 0.5 hours. That is, when the third float 922 alarms, it will take 0.5 hours for the ink in the second ink supply tank 90 to be used up by relying solely on the second ink supply tank 90 to supply ink to the secondary ink cartridge 2.

[0050] In summary, in this application, since a large-capacity second ink supply tank 90 is provided between the first ink supply tank 10 and the secondary ink cartridge 2, the ink supply to the secondary ink cartridge 2 will not be interrupted when the ink in the first ink supply tank 10 is used up and the first ink supply tank 10 is replaced.

[0051] During the process of supplying ink to the second ink tank 90 using the first ink supply assembly 1, if the second float 921 malfunctions, when the ink level in the second ink tank 90 rises to the level of the first float 920 and triggers the float level switch 92, the controller will shut down the first ink supply pump 11. At this time, the first ink tank 10 will stop supplying ink to the second ink tank 90, preventing ink from overflowing from the second ink tank 90, thus avoiding ink waste and environmental pollution. The specific relative positional relationship between the first float 920 and the second ink tank 90 is not limited here and can be set according to actual conditions.

[0052] As one possible implementation, see Figure 1 The secondary ink cartridge 2 has a through hole 93 on its top. This through hole 93 can be connected to the atmosphere, or the secondary ink cartridge 2 can be connected to a negative pressure control component through the through hole 93, or the secondary ink cartridge 2 can be connected to a positive pressure control component through the through hole 93.

[0053] This allows the ink supply system to be adapted to different application scenarios, thus expanding its applicability.

[0054] The specific structures of the aforementioned negative pressure control component and positive pressure control component can be found in the prior art, and will not be described in detail here.

[0055] In one alternative approach, see Figure 1When the through-hole 93 is open to the atmosphere, the ink supply system also includes multiple ink sacs 94. Each ink sac 94 is correspondingly disposed at the ink inlet of each printhead 6, and the ink inlet end of each ink sac 94 is connected to the main ink tube 5 through a corresponding ink supply tube 8. For example, the ink sac 94 is inserted into the ink inlet of the printhead 6.

[0056] The ink sac 94 is a transitional component connecting the ink supply tube 8 and the printhead 6. Its cavity structure can buffer pressure fluctuations generated during ink supply, preventing ink from directly rushing into the printhead 6 and ensuring a uniform and stable ink flow rate. At the same time, the high-precision filter inside the ink sac 94 filters pigment deposits and tiny impurities, preventing impurities from clogging the printhead 6 and reducing the probability of printhead 6 damage.

[0057] In one alternative approach, see Figure 1 The through hole 93 on the secondary ink cartridge 2 can be converted into a positive or negative pressure interface for connection to a positive or negative pressure control component.

[0058] When the above technical solution is adopted, when the ink supply system has different pressure requirements, a positive and negative pressure generating device can be connected to this interface to form a controllable vacuum on the secondary ink cartridge 2.

[0059] For example, when the secondary ink cartridge 2 is connected to the negative pressure control component through the through hole 93, the ink sac 94 does not need to be installed on the printhead 6.

[0060] In summary, the ink supply system provided in this application has a simple structure and logic, is easy to maintain, and performs well, making it suitable for low-cost users. Furthermore, under the combined action of the first and second ink supply components, the two-stage pumps start and stop replenishing ink according to the ink level, and provide uninterrupted ink supply when replacing the first ink tank. Moreover, by utilizing the difference in ink column height to accurately calculate and match the printhead negative pressure, and through centralized filtration and degassing, the cost of the ink supply system is reduced.

[0061] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely exemplary descriptions of the invention as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. An ink supply system, characterized in that, include: First ink supply unit; A secondary ink cartridge, one end of which is connected to the first ink supply assembly; The first ink supply component is used to supply ink to the secondary ink cartridge; A degassing assembly, one end of which is connected to the other end of the secondary ink cartridge; A first filter, one end of which is connected to the other end of the degassing assembly; Main ink tube, one end of which is connected to the other end of the first filter; The printheads are connected to the main ink tube simultaneously through multiple ink supply tubes; the lowest point of the secondary ink cartridge is higher than the highest point of any printhead; the main ink tube supplies ink to the printheads through the ink supply tubes; the number of degassing components and the number of the first filters are both less than the total number of printheads. The liquid level sensor is located inside the secondary ink cartridge; There is a height difference between the lowest point of the secondary ink cartridge and the highest point of the printhead. ; ； in, This is the sum of the pressure required by the printhead and the pressure lost along the flow path; the pressure lost along the flow path is the pressure lost by the ink during its flow from the secondary ink cartridge to the printhead. Ink density; This is the acceleration due to gravity.

2. The ink supply system according to claim 1, characterized in that, The main ink tube is positioned higher than the highest point of any of the printheads, and the main ink tube is positioned lower than the lowest point of the secondary ink cartridge.

3. The ink supply system according to claim 1, characterized in that, The first ink supply component includes: First ink supply tank; The first ink supply pump, one end of which is connected to the first ink supply tank; The second filter has two ends connected to the other end of the first ink pump and the secondary ink cartridge, respectively.

4. The ink supply system according to claim 3, characterized in that, The ink supply system also includes a controller and a second ink supply component; The second ink supply component includes: The second ink supply tank has a highest point lower than the lowest point of the secondary ink cartridge; one end of the second ink supply tank is connected to the first ink supply pump, and the first ink supply assembly is used to supply ink to the second ink supply tank. The second ink supply pump has two ends connected to the other end of the second ink supply tank and the second filter, respectively. A float level switch is located inside the second ink supply tank; the float level switch is connected to the controller.

5. The ink supply system according to claim 4, characterized in that, The float level switch includes three floats, which are spaced apart along the height of the second ink supply tank. The three floats are defined as a first float, a second float, and a third float along the height of the second ink supply tank. The third float is located near the bottom of the second ink supply tank and is spaced apart from the bottom of the second ink supply tank. The controller controls the first ink supply component to supply ink to the second ink tank or stop ink supply based on the signal from the second float. The controller controls the replacement of the first ink supply component based on the signal from the third float.

6. The ink supply system according to claim 5, characterized in that, When the first ink supply component is replaced, the second ink supply tank supplies ink to the secondary ink cartridge for a longer period than the replacement time of the first ink supply component.

7. The ink supply system according to claim 1, characterized in that, The secondary ink cartridge has a through hole on its top; The through-hole is open to the atmosphere; or, the secondary ink cartridge is connected to the negative pressure control component through the through-hole; or, the secondary ink cartridge is connected to the positive pressure control component through the through-hole.

8. The ink supply system according to claim 7, characterized in that, The through hole is connected to the atmosphere, and the ink supply system also includes an ink sac. Each ink sac is correspondingly disposed at the ink inlet of each printhead, and the ink inlet end of each ink sac is connected to the main ink tube through a corresponding ink supply tube.

9. The ink supply system according to claim 1 or 8, characterized in that, The multiple nozzle arrays are arranged in a single configuration; or, the multiple nozzles are distributed at equal intervals along the length of the main ink tube.

10. The ink supply system according to claim 1 or 8, characterized in that, All ink supply tubes connecting the printhead and the main ink tube are of equal length.

Images