Cartridge lid, cartridge, ink jet print head and ink jet printer

Abstract

This invention relates to the field of inkjet printing technology. When the external pressure changes significantly relative to the pressure after ink filling, particularly due to possible air bubbles trapped in the ink reservoir, the cartridge, whose ink reservoir is connected to the external environment via a vent, suffers ink leakage. This invention provides a cartridge cover (15) with an expansion space (25) formed between an outer cover member (40) and an inner cover member (27). This expansion space (25) is connected to the external environment via a vent (17) and has an inlet (26) through which ink can flow into the expansion space (25). This invention also provides a cartridge, an inkjet printhead, and an inkjet printer.

Description

Technical Field

[0001] This invention relates to the field of inkjet printing technology, and more particularly, to preventing ink leakage from the vent to the outside of the cartridge due to shipping and / or using the inkjet printhead at an altitude different from the factory altitude, and more particularly, to a cartridge cover, cartridge, inkjet printhead, and inkjet printer. Prior Technology

[0002] As illustrated in Figures 1a, 1b, and 2, the cartridge 37 of the inkjet printhead includes a cartridge body 4 and a cartridge cover 15 for covering an opening 38 of the cartridge body 4. An ink reservoir 10 for containing ink is formed within the cartridge body 4. The cartridge body 4 further includes an ink flow opening 13 communicating the ink reservoir 10 with the jet chamber of the inkjet printhead, wherein the ink flow opening 13 communicates with the ink reservoir 10 via a filter 12 and a fitting 11.

[0003] Precise control of the ink flow through the ejection nozzles of the inkjet printhead's ejection chamber is essential, as it is a fundamental prerequisite for achieving high-quality printing with inkjet printers. One system that helps provide this ink flow control is a back pressure system, which creates a slight negative pressure in the liquid within the ink reservoir of the printhead's cartridge. This negative pressure prevents accidental ink leakage. Otherwise, such leakage could occur when the printhead is idle or when the cartridge experiences sudden acceleration during transport.

[0004] As illustrated in Figures 1a, 1b and 2, possible back pressure systems well known in the art employ porous components 14 (e.g., open-cell foam), fibrous components, or a combination of both, which are inserted into the ink reservoir 10 of the cartridge 37 to create a negative pressure in the liquid contained within the ink reservoir 10 by capillary effects generated by the porous network or between fibers, as described in patent EP 3302983 B1.

[0005] When back pressure is generated by capillary force originating from the porous member 14 inserted into the ink reservoir 10, the ink reservoir 10 must be in communication with the external environment. In other words, the boundary liquid surface within the porous member 14 must be at atmospheric pressure. If the ink reservoir 10 is not in communication with the external environment, and the ink level in the ink reservoir 10 decreases due to ink ejection during printing, the pressure of the liquid contained in the ink reservoir 10 will drop far beyond a suitable back pressure value, thereby preventing further ejection from the inkjet printhead.

[0006] To provide suitable communication with the external environment, the cartridge cover 15 typically includes a vent 17 in addition to the ink filling hole 16. Specifically, as illustrated in Figures 1a, 1b, 2, and 3, the cartridge cover 15 has an ink filling hole 16 and a vent 17. A needle passes through the ink filling hole 16 to penetrate most of the path across the porous member 14 to fill the ink reservoir 10 with ink. The vent 17 serves to communicate the ink reservoir 10 with the external environment. The vent 17 is located at one end of a shallow serpentine venting channel 18 molded into the outer surface of the cartridge cover 15. The ink filling hole 16 is relatively large and is sealed after filling with an adhesive label 19 or a stopper (not shown) to prevent excessive ink evaporation. The adhesive label 19 overlaps not only the ink filling hole 16 but also the vent 17. An adhesive label 19 is closed on top of most of the shallow serpentine venting channel 18, thus serving as a top plate surface. The vent outlet 20, located at the very end of the shallow serpentine venting channel 18, remains uncovered, allowing the ink reservoir 10 to communicate with the external environment. The small cross-section and suitable length of the shallow serpentine venting channel 18 maintain a low evaporation rate, while also maintaining pressure balance between the inside and outside of the ink reservoir 10, even during printing. Of course, two separate labels (not shown) can be applied to the ink filling hole 16 and the vent 17, respectively. As illustrated in Figure 4, the inner surface of the cartridge cover 15, in addition to the ink filling hole 16 and the vent 17, is typically provided with a peripheral sealing frame 22 suitable for ultrasonic bonding with the cartridge body 4, as well as a plurality of ribs 23 and an additional outer peripheral reinforcing frame 41. These ribs 23 and the additional outer peripheral reinforcing frame 41 are designed to properly reinforce the cartridge cover 15, thereby preventing any deformation or breakage of the cartridge cover 15. Typically, such ribs 23 and outer peripheral reinforcing frames 41 are obtained simultaneously during the molding process of the cartridge cover 15.

[0007] The ink filled into the ink reservoir 10 permeates most of the porous member 14. Capillary action prevents the ink from leaving the porous member 14. However, the ink has a certain amount of internal flow across the porous member 14, especially when the porous member 14 is a fibrous member that readily allows ink to move along the fiber direction. Therefore, handling an ink-filled inkjet printhead may result in some air being trapped in the porous member 14. This trapped air may even be surrounded by ink. Due to possible operational errors or a lack of airtight seal between the ink filling orifice 16 and the needle during the ink filling stage, some additional air trapping may even occur in the tube 11. In short, there is a possibility that some air islands remain trapped within the ink in the inkjet printhead.

[0008] After filling, atmospheric pressure surrounding the inkjet printhead also exists in the portion of the ink reservoir 10 without ink. In the liquid contained within the inkjet printhead, the pressure is due to atmospheric pressure, which is increased by the hydrostatic pressure of the liquid column and decreased by the capillary pressure of the porous member 14. The capillary action of the porous member 14 (depending on the pore size, the surface tension of the ink, and the wettability of the porous member material) is carefully designed to provide a lower pressure relative to the external environment for the liquid contained in the ink reservoir.

[0009] Before the inkjet printhead is ready for shipment, the nozzles are sealed with a suitable adhesive tape to prevent ink evaporation and protect the nozzles from particulate contamination or mechanical scratching. Finally, the inkjet printhead is placed in a plastic cup and heat-sealed with a double-layered plastic-aluminum packaging lid. As a result, the inkjet printhead is sealed within a closed container with an internal pressure equal to atmospheric pressure at the factory.

[0010] However, during the shipment of inkjet printheads or when they are to be used at high altitudes, the sealed container may experience significant pressure changes. For example, in air transport, the cargo hold may be under low pressure during flight. Similarly, the final destination of the inkjet printhead may be in an environment with significantly different pressures than the factory environment due to varying altitudes. These pressure changes within the sealed container can lead to an imbalance between the internal pressure and the ambient pressure. This pressure imbalance pulls the packaging lid outwards, causing the internal pressure of the sealed container to decrease relative to the original pressure in the factory.

[0011] Because the ink reservoir is connected to the area outside the cartridge through a vent, if the environment is under a lower pressure than the factory pressure, the air trapped inside the porous component may expand, thereby pulling out the ink. When the cartridge is in a sealed container or when the end user opens the packaging cover, the ink may leak out from the vent.

[0012] Seal the vent with an additional label or removable stopper only prevents ink leakage within the sealed cup, but it will not work if the final destination pressure is significantly lower than the plant pressure: removing the additional label or stopper will cause a sudden pressure imbalance inside, causing ink to spray out of the vent. This phenomenon can also occur if no air is trapped within the porous structure. Sudden disturbances in the internal pressure of a sealed container can easily cause ink to spray out of the vent in any way, because the communication between the liquid surface in the ink reservoir and the outside is through a short distance and the ink can flow almost directly outward.

[0013] Figure 2 schematically depicts the ink spraying from the vent 17. The relative positions of the ink reservoir 10 and the cartridge cover 15 are shown in an exploded view, where the sudden ink jet 21 caused by pressure imbalance is schematically indicated by arrows. The ink rapidly covers a short, direct path toward the ink filling hole 16 and the vent 17 of the cartridge cover 5. The ink filling hole 16 is sealed by an adhesive label 19 (Figure 3b), which also overlaps the vent 17 and most of the shallow serpentine vent channel 18, thus leaving a vent outlet 20 communicating with the outside. The shallow serpentine vent channel 18 has a very small volume below the adhesive label 19 and can be rapidly filled with ink, resulting in ink spraying out from the vent outlet 20 at the very end of the shallow serpentine vent channel 18. Summary of the Invention

[0014] To solve the above technical problems, the solution of the present invention consists of a cartridge cover having an expansion space connected to a vent hole, so as to collect any possible ink jets caused by the imbalance between the internal pressure of the ink reservoir and the ambient pressure outside the ink reservoir due to changes in ambient pressure, thereby preventing ink leakage to the outside of the cartridge.

[0015] In one embodiment of the present invention, a cartridge cover is provided. The cartridge cover includes an outer cover member and an inner cover member. The outer cover member is provided with an ink filling hole and a vent hole. The inner cover member is attached to the outer cover member and overlaps the vent hole. An expansion space is formed between the outer cover member and the inner cover member. The expansion space has an inlet through which ink can flow into the expansion space, and the expansion space communicates with the external environment through the vent hole.

[0016] The cartridge cover of this invention prevents ink from reaching the area outside the cartridge via a direct connection during a short stroke. Instead, the ink is forced through a longer expansion space, thereby damping the potential intensity of the spray and providing an internal expansion volume or internal expansion space capable of accommodating all or most of the ink that may have shifted due to pressure imbalance.

[0017] Preferably, the expansion space is a circuitous expansion loop. Giving the expansion space a circuitous shape will enhance both the damping effect and the available volume that needs to be traversed. The circuitous expansion loop forces the ink flowing from the inlet into the expansion space to travel a longer flow path and spend more time before being sprayed out of the vent.

[0018] Preferably, the expansion space contains a porous material. This porous material can enhance the damping of the intensity of ink flow without impairing fluid communication with the outside.

[0019] Preferably, the expansion space comprises a plurality of expansion chambers fluidly connected via narrow connecting passages, and each expansion chamber is surrounded by a chamber wall connected to the outer cover member and the inner cover member. The abrupt change in width along the expansion loop caused by the plurality of narrow connecting passages contributes to flow damping.

[0020] Preferably, the chamber walls comprise two curved walls surrounding the vent.

[0021] Preferably, the walls of two adjacent chambers are spaced apart from each other to form such narrow connecting passages.

[0022] Preferably, the narrow connecting passage is formed in the wall of the chamber.

[0023] Preferably, the inner cover member is parallel to the outer cover member.

[0024] In a second embodiment of the invention, a cartridge is provided. The cartridge includes a cartridge body and the aforementioned cartridge cover. The cartridge body has an opening and an ink flow orifice. An ink reservoir for containing ink is formed within the cartridge body. The cartridge cover covers the opening.

[0025] Preferably, the cartridge includes a porous component and / or a fiber component inserted into the ink reservoir.

[0026] In a third embodiment of the present invention, an inkjet printhead is provided. This inkjet printhead includes the cartridge mentioned above.

[0027] Preferably, the inkjet printhead (thermal inkjet printhead) includes a microfluidic device attached to the cartridge. The microfluidic device includes a plurality of resistors, a plurality of ejection chambers, and a nozzle plate. The ejection chambers are disposed above the resistors and are in fluid communication with the ink flow openings. The nozzle plate covers the ejection chambers and is provided with ejection nozzles for ejecting ink from the ejection chambers.

[0028] In a fourth embodiment of the present invention, an inkjet printer comprising the inkjet printhead mentioned above is provided. Simple Explanation of the Diagram

[0029] Non-limiting and non-exhaustive embodiments of the invention will be described by way of example with reference to the following accompanying drawings, in which:

[0030] Figures 1a and 1b illustrate exploded views of a known cartridge.

[0031] Figure 2 illustrates a schematic diagram of the cartridge shown in Figures 1a and 1b.

[0032] Figure 3a illustrates a schematic diagram of the outer surface of the cartridge cover of the cartridge shown in Figures 1a and 1b, where the adhesive label has been removed.

[0033] Figure 3b is a schematic diagram of the outer surface of the cartridge cover of the cartridge shown in Figures 1a and 1b.

[0034] Figure 4 shows a bottom view of the cartridge cover of a known cartridge.

[0035] Figure 5 shows a perspective view of an inkjet printhead according to one embodiment of the present invention.

[0036] Figures 6a and 6b illustrate exploded views of the cartridge of the inkjet printhead in Figure 5.

[0037] Figure 7 shows a partial cross-sectional schematic diagram of the microfluidic device of the inkjet printhead in Figure 5.

[0038] Figure 8 shows a perspective view of a cartridge cover according to an embodiment of the present invention, wherein the inner cover member has been removed.

[0039] Figure 9 shows a bottom view of the outer cover member of a cartridge cover according to an embodiment of the present invention.

[0040] Figure 10 shows a perspective view of a cartridge cover according to an embodiment of the present invention.

[0041] Figure 11 shows a bottom view of the cartridge cover of a cartridge according to an embodiment of the present invention.

[0042] Figure 12 shows a perspective view of a cartridge cover according to another embodiment of the present invention, wherein the inner cover member has been removed.

[0043] Figure 13 shows a bottom view of the outer cover member of the cartridge cover according to another embodiment of the present invention.

[0044] Figure 14 shows a schematic diagram of the inner surface of the outer cover member of the cartridge cover according to yet another embodiment of the present invention.

[0045] Figure 15 shows a cross-sectional view of the cartridge cover corresponding to the chamber wall. Implementation

[0046] To make the above and other features and advantages of the present invention clearer, the present invention will be further described in conjunction with the following drawings. It should be understood that the specific embodiments of the present invention are illustrative and not intended to be limiting.

[0047] This invention provides a cartridge cover, a cartridge, an inkjet printhead, and an inkjet printer. Figure 5 shows a perspective view of an inkjet printhead 1 according to one embodiment of the invention. In this embodiment, the inkjet printhead 1 is a thermal inkjet printhead, such as a bubble jet inkjet printhead. In other embodiments, the inkjet printhead 1 may also be a piezoelectric inkjet printhead.

[0048] As illustrated in Figures 5, 6a, and 6b, the inkjet printhead 1 includes one or more cartridges 37. These cartridges 37 may each contain ink of different colors. Each cartridge 37 includes a cartridge body 4, which is generally made of a plastic material. The cartridge body 4 has an opening 38 and an ink flow opening 13. An ink reservoir 10 for containing ink is formed within the cartridge body 4. A filter device 12 is disposed between the ink flow opening 13 and the ink reservoir 10. In this embodiment, the filter device 12 is a mesh filter. Depending on the situation, the filter device 12 communicates with the ink flow opening 13 via a pipe 11 (e.g., a vertical pipe), which is capped at its boundary with the ink reservoir 10 and terminated at the other end with the ink flow opening 13.

[0049] As illustrated in Figure 5, the inkjet printhead 1 further includes a microfluidic device 2 attached to the cartridge 37. For example, the microfluidic device 2 is adhered to the cartridge body 4 of the cartridge 37 via a sealant that provides both mechanical strength and airtightness for the connection between the microfluidic device 2 and the cartridge 37. The microfluidic device 2 is in fluid communication with the ink flow opening 13 of the cartridge 37, allowing ink contained in the ink reservoir 10 of the cartridge 37 to flow through the ink flow opening 13 to the microfluidic device 2. The microfluidic device 2 is electrically activated via a contact pad 3.

[0050] As illustrated in Figure 7, the microfluidic device 2 includes a plurality of jet chambers 6 and a plurality of resistors 5 corresponding to the plurality of jet chambers 6. The jet chambers 6 are positioned above the resistors 5 and are in fluid communication with the ink flow openings 13 of the cartridge 37 within the fluid circuit 7. Therefore, it can be said that the jet chambers 6 are in fluid communication with the ink flow openings 13. Ink from the ink flow openings 13 flows in the fluid circuit 7 and reaches the jet chambers 6. The fluid circuit 7 is patterned in a suitable polymer layer called a barrier layer 39. A nozzle plate 8 is positioned on the barrier layer 39 and seals the microfluidic device 2 at the top. The nozzle plate 8 also covers the jet chambers 6. The nozzle plate 8 is provided with jet nozzles 9 for each jet chamber 6. The jet nozzles 9 are used to spray ink from the jet chambers 6. Specifically, a sudden current pulse can be applied via the resistors 5 as needed, causing the ink layer to evaporate rapidly. The high vapor pressure causes the vapor bubbles to expand, which pulls the ink above out of the jet nozzle 9, thus producing the ejection of ink droplets. After ejection, new ink is dispensed from the ink reservoir 10 to refill the jet chamber 6 and the jet nozzle 9.

[0051] As mentioned above, a back pressure system is used in the inkjet printhead 1 to assist in providing control over the ink flow. In this embodiment, as illustrated in Figures 6a and 6b, a porous member 14 (e.g., open-cell foam) and / or a fibrous member can be inserted into the ink reservoir 10 to create a negative pressure in the liquid contained within the ink reservoir 10, generated by the capillary effect between the porous network or fibers. However, other methods can be used to generate suitable back pressure in the liquid. For example, a shroud with an opening that is in fluid communication with the tubing and the jet chamber can be used; the shroud housing is mechanically biased outward via a metal spring or some other elastic element. In addition to the communication opening with the tubing, the shroud is also fluidly isolated from the external environment. The elastic components must be carefully calibrated to provide suitable back pressure throughout the life of the inkjet printhead.

[0052] As illustrated in Figures 6a and 6b, the cartridge 37 further includes a cartridge cover 15 for covering the opening 38 of the cartridge body 4. Specifically, the peripheral sealing frame 22 of the cartridge cover 15 can be coupled to the cartridge body 4 such that the opening 38 of the cartridge body 4 is covered by the cartridge cover 15. To eliminate or at least mitigate the effects of the pressure imbalance between the inside and outside of the cartridge 37, a specific ink expansion volume or expansion space 25 is formed in the cartridge cover 15. The purpose is to prevent ink from reaching the outside of the cartridge 37 via a direct connection in a short stroke. Instead, the ink is forced through a longer expansion space 25, particularly a circuitous expansion path or expansion loop, before reaching the vent 17, thereby damping the possible intensity of spray and providing an internal expansion volume or internal expansion space 25 capable of accommodating all or most of the ink displaced due to pressure imbalance.

[0053] As illustrated in Figures 6a, 6b, and 8 through 11, the cartridge cover 15 includes an outer cover member 40 and an inner cover member 27 attached to the outer cover member 40. It should be noted that terms describing positional relationships such as "outer," "inner," "upper," and "lower" are used relative to the case where the cartridge cover 15 covers the opening 38 of the cartridge body 4. The outer cover member 40 is provided with an ink filling hole 16 for filling ink into the ink reservoir 10 of the cartridge 37 and a vent hole 17 for communicating the ink reservoir 10 of the cartridge 37 with the external environment. The vent hole 17 is located at one end of a shallow serpentine venting channel 18 molded in the outer surface of the outer cover member 40. The ink filling hole 16 is relatively large, allowing ink filling tools such as needles to fill ink into the ink reservoir 10. The inner cover member 27 is disposed on the inner side of the outer cover member 40 and overlaps the vent hole 17. It is understood that the inner cover member 27 does not overlap the ink filling hole 16 to avoid affecting ink filling via the ink filling hole 16. An expansion space 25 with an inlet 26 is formed between the outer cover member 40 and the inner cover member 27. The expansion space 25 communicates with the external environment via the vent hole 17. The inlet 26 may be located on the opposite side of the vent hole 17; for example, the inlet 26 may be located within the inner cover member 27. Alternatively, the inlet 26 may also be located between the outer cover member 40 and the inner cover member 27. When the cartridge cover 15 covers the opening 38 of the cartridge body 4, the inlet 26 allows ink from the ink reservoir 10 to flow into the expansion space 25, and the vent hole 17 communicates the expansion space 25 with the external environment. The inner surface (e.g., lower surface) of the outer cover member 40 serves as the top plate of the expansion space 25, while the outer surface (e.g., upper surface) of the inner cover member 27 serves as the bottom plate of the expansion space 25. In one possible embodiment, the inner cover member 27 is parallel to the outer cover member 40. The inner cover member 27 may be detachably attached to the outer cover member 40. The inner cover member 27 may also be bonded to the outer cover member 40 using a suitable adhesive or bonding agent, ultrasonic welding, or any other method known in the art. Furthermore, the inner cover member 27 may even be molded, just like the rest of the cartridge cover 15, but the manufacturing process would ultimately be very complex and expensive.

[0054] Preferably, the expansion space 25 is a circuitous expansion loop. Giving the expansion space 25 a circuitous shape will enhance both the damping effect and the available volume that needs to be traversed. The circuitous expansion loop forces the ink flowing from the inlet 26 into the expansion space 25 to travel a longer flow path and take more time before being sprayed out from the vent 17.

[0055] One type of circuitous expansion loop can be viewed as a series of expansion chambers connected via narrow connecting passages. Specifically, as illustrated in Figures 8 through 13, expansion space 25 may contain a plurality of expansion chambers fluidly connected via narrow connecting passages. For example, referring to Figure 14, expansion chambers 31 and 32 are connected via narrow connecting passage 33. The abrupt change in width along the expansion loop caused by the plurality of narrow connecting passages 33 contributes to flow damping.

[0056] The expansion chamber may be surrounded by a chamber wall 24 and an outer peripheral reinforcing frame 41, which in turn connects to an outer cover member 40 and an inner cover member 27. The outer cover member 40 and the inner cover member 27 may be connected to the chamber wall 24 and the outer peripheral reinforcing frame 41 without affecting the peripheral sealing frame 22. The chamber wall 24 may be formed by modifying the rib design of the existing cartridge cover (one of which is illustrated in Figure 4) by adding additional parts or modifying the length and position of existing ribs 23. The chamber wall 24 and the outer peripheral reinforcing frame 41 may be connected to the outer cover member 40 and the inner cover member 27 using a suitable adhesive or bonding agent, ultrasonic welding, or any other method well known in the art.

[0057] Depending on the circumstances, the expansion space 25 may contain some kind of porous material. For example, in another embodiment illustrated in Figures 12 and 13, a portion of the expansion space 25 in the cartridge cover 15 may even contain some kind of porous material 28 to enhance damping of the intensity of ink flow without impairing fluid communication with the outside. The porous material 28 may be accommodated in only one expansion chamber, or in multiple expansion chambers, or even in all expansion chambers.

[0058] In yet another embodiment, some of the chamber walls of the expansion chamber have a curved profile rather than a straight profile, as illustrated in Figure 14. In this embodiment, the chamber walls include two curved walls 29 surrounding the vent 17. The two curved walls 29 are spaced apart from each other, thereby forming two narrow connecting passages 30 for ink.

[0059] Narrow connecting passages can be obtained in different ways, as illustrated in Figure 15. A cross-section of the cartridge cover 15 corresponding to the chamber wall 24 shows various possible ways of obtaining narrow connecting passages. For example, two adjacent chamber walls 24 are spaced apart from each other, and the narrow connecting passage 34 is created by the gap between the two adjacent chamber walls 24, which extends from the outer cover member 40 to the inner cover member 27. Another example is a narrow connecting passage 35 configured as a gap within the chamber wall 24, where the gap does not reach the outer cover member 40, but a riser connects both sides of the gap, resulting in a shallow gap. Yet another example is a narrow connecting passage 36 completely within the chamber wall 24 and through a hole configured to penetrate the chamber wall 24. The first two variations can be easily obtained using standard molding processes, while the latter requires a more complex manufacturing process. Regardless, all of them can be advantageously employed.

[0060] The described embodiments are merely examples of the inventive concept. Without departing from the spirit and scope of the invention, the detailed features of the expansion space or expansion circuit can be appropriately varied or combined according to different solutions. The expansion space integrated into the cartridge cover of the inkjet printhead cartridge effectively solves the problem caused by the pressure imbalance between the inside and outside of the cartridge, thereby correcting logistical shortcomings and enabling the correct use of the inkjet printhead at different altitudes.

[0061] The various technical features described above can be combined arbitrarily. Although not all possible combinations of the various technical features are described, all such combinations should be considered within the scope described in this specification, provided that they do not conflict.

[0062] Although the invention has been described in conjunction with embodiments, those skilled in the art should understand that the above description and drawings are illustrative rather than limiting, and the invention is not limited to the disclosed embodiments. Various modifications and variations are possible without departing from the scope of the invention.

[0063] 1: Inkjet printhead 2: Microfluidic devices 3: Contact pad 4: Cartridge body 5: Resistors 6: Jet Chamber 7: Fluid Circuit 8: Nozzle plate 9: Injection nozzle 10: Ink reservoir 11: Pipe fittings 12: Filtration device 13: Ink flow opening 14: Porous components 15: Cartridge cover 16: Ink filling hole 17: Vent hole 18: Shallow serpentine ventilation channel 19: Sticky Labels 20: Ventilation outlet 21: Ink Beam Flow 22: Peripheral sealing frame 23: Ribs 24: Chamber wall 25: Expansion Space 26: Entrance 27: Inner cover components 28: Porous materials 29: Curved Wall 30: Narrow connecting pathway 31: Expansion chamber 32: Expansion chamber 33: Narrow connecting pathways 34: Narrow connecting pathway 35: Narrow connecting pathway 36: Narrow connecting pathway 37: Cartridge 38: Opening 39: Barrier layer 40: Outer cover components 41: External perimeter reinforcement frame

Claims

1. A cartridge cover, comprising: an outer cover member having an ink filling hole and a vent hole; and an inner cover member attached to the outer cover member and overlapping the vent hole; wherein an expansion space is formed between the outer cover member and the inner cover member, the expansion space having an inlet between the outer cover member and the inner cover member, through which ink can flow into the expansion space, and the expansion space communicating with the external environment through the vent hole.

2. The cartridge cover as described in claim 1, wherein the expansion space is a circuitous expansion loop.

3. The cartridge cover as described in claim 1 or 2, wherein the expansion space contains a porous material.

4. The cartridge cover as claimed in claim 1, wherein the expansion space comprises a plurality of expansion chambers fluidly connected via a narrow communication passage, and each expansion chamber is surrounded by a chamber wall connected to the outer cover member and the inner cover member.

5. The cartridge cover as claimed in claim 4, wherein the chamber walls include two curved walls surrounding the vent.

6. The cartridge cover as claimed in claim 4, wherein two adjacent chamber walls are spaced apart from each other to form such narrow communication passages.

7. The cartridge cover as claimed in claim 4, wherein the narrow communication passage is formed in the chamber wall.

8. The cartridge cover as claimed in claim 1, wherein the inner cover member is parallel to the outer cover member.

9. A cartridge comprising: a cartridge body having an opening and an ink flow orifice, wherein an ink reservoir for receiving ink is formed within the cartridge body; and a cartridge cover as described in any one of claims 1 to 8, the cartridge cover being used to cover the opening.

10. The cartridge as claimed in claim 9, wherein the cartridge includes a porous member and / or a fiber member inserted into the ink reservoir.

11. An inkjet printhead comprising a cartridge as described in claim 9 or 10.

12. The inkjet printhead as claimed in claim 11, wherein the inkjet printhead is a thermal inkjet printhead, comprising a microfluidic device attached to the cartridge, the microfluidic device comprising: a plurality of resistors; a plurality of ejection chambers disposed above the resistors and in fluid communication with the ink flow opening; and a nozzle plate covering the ejection chambers and provided with ejection nozzles for ejecting ink from the ejection chambers.

13. An inkjet printer comprising an inkjet printhead as described in claim 11 or 12.

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