Pressure control unit and drying method thereof

Abstract

To reduces an amount of a liquid that remains at a boundary between a pressure reception plate and flexible member.SOLUTION: A pressure control unit has: a pressure chamber 11a which can accommodate a liquid; an inlet 30a which causes the liquid to flow into the pressure chamber 11a; an outlet 31a which causes the liquid to flow out from the pressure chamber 11a. At least a part of a wall forming the pressure chamber 11a is formed from a flexible member 16a. The pressure control unit has: a pressure reception plate 24a which is provided on an inner face of the flexible member 16a, and displaces toward an inner side and an outer side of the pressure chamber 11a; a valve member 32a which opens / closes the inlet 30a according to displacement of the pressure reception plate 24a; and an inner flow path 25 which extends along the inner face of the flexible member 16a at a boundary between the pressure reception plate 24a and the flexible member 16a, and opens to a side face of the pressure reception plate 24a.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a pressure control unit for a liquid ejection head that ejects liquid such as ink. [Background technology]

[0002] The liquid ejection head is equipped with a pressure control unit for adjusting the pressure in the ejection ports and the flow channels communicating with the ejection ports. The pressure control unit has a pressure chamber with an inlet and an outlet, and part of the side wall of this pressure chamber is formed from a flexible member. A pressure plate is provided on the inner surface of the flexible member, and the inlet is opened and closed according to the displacement of this pressure plate. Patent Document 1 describes a pressure control unit with a structure similar to the above-mentioned pressure chamber. Generally, in the manufacturing process of a liquid ejection head, the ejection operation of the liquid ejection head is inspected. After the inspection is completed, the inside of the liquid ejection head, including the pressure control unit, is cleaned with a cleaning liquid. After cleaning, the inside of the liquid ejection head is dried and the liquid ejection head is packaged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 7,862,138 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the pressure control unit described above, cleaning liquid may seep into the gap between the pressure plate and the flexible member, and may remain in the gap even after drying. If the amount of remaining cleaning liquid is small, this is not a problem, but if the liquid ejection head is packaged with a large amount of liquid remaining, the humidity inside the package may rise, causing corrosion of the substrate.

[0005] An object of the present invention is to reduce the amount of liquid remaining at the boundary between the pressure plate and the flexible member. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a pressure control unit having a pressure chamber capable of accommodating liquid, an inlet for allowing liquid to flow into the pressure chamber, and an outlet for allowing liquid to flow out of the pressure chamber, wherein at least a portion of a wall forming the pressure chamber is formed from a flexible member, the pressure control unit having a pressure plate provided on an inner surface of the flexible member and displacing toward the inside and outside of the pressure chamber, a valve member for opening and closing the inlet in response to displacement of the pressure plate, and an internal flow path extending along the inner surface of the flexible member at the boundary between the pressure plate and the flexible member and opening to a side surface of the pressure plate. The flexible member has a plurality of protrusions on the inner surface thereof, and the protrusions, the inner surface, and a first surface of the pressure-receiving plate facing the inner surface form the internal flow path. It is characterized by: [Effects of the Invention]

[0007] According to the present invention, the amount of liquid remaining at the boundary between the pressure-receiving plate and the flexible member can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a liquid supply system. [Figure 2] FIG. 2 is a perspective view schematically illustrating the appearance of a pressure control unit. [Figure 3] FIG. 3 is a cross-sectional view of the pressure control unit taken along line AA in FIG. 2. [Figure 4] FIG. 2 is a schematic diagram showing a state in which the pressure control unit is filled with liquid. [Figure 5] FIG. 10 is a schematic diagram showing a state in which the cleaning liquid inside the pressure control unit has been discharged. [Figure 6] FIG. 6 is an enlarged view of a portion of the pressure control unit shown in FIG. 5. [Figure 7] FIG. 1 is a schematic diagram showing a pressure control unit according to a first embodiment of the present invention. [Figure 8] FIG. 8 is a top view of a pressure-receiving plate of the pressure control unit shown in FIG. [Figure 9] 9 is a cross-sectional view of the pressure plate taken along line CC in FIG. 8. [Figure 10] FIG. 8 is a cross-sectional view of the pressure control unit taken along line BB in FIG. 7. [Figure 11] FIG. 2 is a schematic diagram showing a state in which the pressure control unit is filled with liquid. [Figure 12] FIG. 10 is a schematic diagram showing a state in which the cleaning liquid inside the pressure control unit has been discharged. [Figure 13] FIG. 13 is an enlarged view of a portion of the pressure control unit shown in FIG. [Figure 14] FIG. 10 is a schematic view showing a pressure-receiving plate of a first modified example. [Figure 15] 10(a) is a top view showing a pressure plate of a second modified example, (b) is a cross-sectional view taken along line DD, and (c) is a perspective view of the cross-sectional portion taken along line DD. [Figure 16] FIG. 10 is a schematic view showing a pressure-receiving plate of a third modified example. [Figure 17] 10(a) is a plan view showing a pressure-receiving plate of a pressure control unit according to a second embodiment of the present invention, and FIG. 10(b) is a schematic cross-sectional view taken along line EE. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the components described in the embodiments are merely examples and are not intended to limit the scope of the present invention.

[0010] First, a liquid supply system for supplying liquid to a liquid ejection head to which the pressure control unit of the present invention can be applied will be described. 1 shows an example of a liquid supply system. This liquid supply system has a liquid storage tank 40, a waste liquid tank 41, pumps 42a and 42b, and a liquid ejection head 200. The liquid storage tank 40 and the liquid ejection head 200 are connected via the pump 42a, and the waste liquid tank 41 and the liquid ejection head 200 are connected via the pump 42b. The liquid storage tank 40 can store liquid such as ink or cleaning liquid. When the pumps 42a and 42b are operated, the liquid is supplied from the liquid storage tank 40 to the liquid ejection head 200, and the liquid that has passed through the inside of the liquid ejection head 200 is collected in the waste liquid tank 41.

[0011] The liquid ejection head 200 has a filter unit 50, a pressure control unit 100, and a liquid ejection unit 101. The filter unit 50 has a filter 51 for preventing foreign matter from entering the inside of the head. The pressure control unit 100 controls the pressure inside the liquid ejection head 200, and has a high-pressure side flow path (H) and a low-pressure side flow path (L). The negative pressure in the high-pressure side flow path (H) is greater than the negative pressure in the low-pressure side flow path (L). The liquid ejection unit 101 has a recording element substrate (not shown) equipped with ejection ports for ejecting liquid. After passing through a filter 51, the liquid is supplied to a high-pressure side flow path (H) and a low-pressure side flow path (L). The high-pressure side flow path (H) and the low-pressure side flow path (L) are connected via a flow path formed in the recording element substrate within the liquid ejection unit 101. When the pumps 42a and 42b operate to supply liquid, a pressure difference is generated within the liquid ejection head 200 by the pressure control unit 100. Then, the liquid flowing through the high-pressure side flow path (H) merges with the liquid flowing through the low-pressure side flow path (L) via a flow path formed in the flow path recording element substrate, and the entire liquid ejection head 200 is filled with liquid.

[0012] Next, the configuration of the pressure control unit 100 will be described in detail. Fig. 2 is a perspective view schematically showing the appearance of the pressure control unit 100. Fig. 3 is a cross-sectional view showing the cross section of the pressure control unit 100 taken along line AA in Fig. 2. The pressure control unit 100 has a case 5 equipped with a high-pressure side pressure control structure and a low-pressure side pressure control structure in order to maintain a negative pressure in the liquid supplied to the liquid ejection head 200. Since the high-pressure side pressure control structure and the low-pressure side pressure control structure are basically the same structure, the configuration of the low-pressure side pressure control structure will be described in detail here, and a description of the configuration of the high-pressure side pressure control structure will be omitted.

[0013] As shown in FIG. 3, the case 5 has a pressure chamber 11a on the low-pressure side. The pressure chamber 11a has an inlet 30a and an outlet 31a and is capable of containing a liquid. The liquid can be supplied into the pressure chamber 11a from the inlet 30a, and the liquid in the pressure chamber 11a can be discharged from the outlet 31a. At least a portion of the wall that constitutes the pressure chamber 11a is formed of a flexible member 16a. The flexible member 16a is, for example, a flexible film. The flexible member 16a is deformable toward the inside and outside of the pressure chamber 11a. A pressure-receiving plate 14a is provided on the inner surface of the flexible member 16a. The pressure-receiving plate 14a has an abutment surface 14a-1 that abuts against the inner surface of the flexible member 16a, and a portion of the abutment surface 14a-1 is fixed to the inner surface of the flexible member 16a. A negative pressure spring 13a is attached to the pressure-receiving plate 14a. The biasing force of the negative pressure spring 13a causes the flexible member 16a to deform outward from the pressure chamber 11a. When suction is applied through the outlet 31a to reduce the pressure in the pressure chamber 11a, the flexible member 16a deforms inward from the pressure chamber 11a. As the flexible member 16a deforms, the pressure-receiving plate 14a is displaced inward and outward from the pressure chamber 11a.

[0014] The pressure chamber 11a is provided with a valve member 32a that opens and closes the inlet 30a in response to the displacement of the pressure plate 14a. The valve member 32a has a valve element 12a that closes the inlet 30a and a valve spring 17a that urges the valve element 12a toward the inlet 30a. A cap 15a is provided at one end of the valve spring 17a. The cap 15a contacts the inner wall of the pressure chamber 11a at a position facing the inlet 30a. The valve element 12a is made of an elastic material such as rubber. The valve element 12a has a shaft 22a and an arm 12a-1 that extends from near the shaft 22a toward the pressure plate 14a. When the valve element 12a closes the inlet 30a, the shaft 22 abuts against the edge of the inlet 30a. When the pressure-receiving plate 14a is displaced inward of the pressure chamber 11a, the arm 12a-1 comes into contact with the pressure-receiving plate 14a.

[0015] The inlet 30a communicates with the liquid flow chamber 10a-1. The liquid flow chamber 10a-1 communicates with the filter unit 50 shown in FIG. 1. The outlet 31a communicates with the liquid flow chamber 10a-2. The liquid flow chamber 10a-2 communicates with the liquid discharge unit 101 shown in FIG. 1. The case 5 also has a pressure control structure on the high-pressure side similar to that on the low-pressure side. The reference numerals for the elements on the high-pressure side are marked with "b" instead of "a." The biasing force of the negative pressure spring 13a on the low-pressure side is greater than the biasing force of the negative pressure spring 13b on the high-pressure side.

[0016] Fig. 4 is a schematic diagram showing a state in which the pressure control unit 100 is filled with liquid. Fig. 4 shows a cross section of the pressure control unit 100 taken along line AA in Fig. 2. Here, a state in which the low-pressure pressure chamber 11a and the liquid circulation chamber 10a-1 are connected to each other by the supply of liquid will be described. The pressure chamber 11a is depressurized by suction using the pump 42b from the downstream side of the pressure control unit 100, thereby filling the pressure chamber 11a with liquid. Specifically, when the pressure chamber 11a is depressurized, the flexible member 16a deforms inward, displacing the pressure-receiving plate 14a. As the pressure-receiving plate 14a displaces, the negative pressure spring 13a contracts, causing the pressure-receiving plate 14a to come into contact with the arm 12a-1. When the pressure-receiving plate 14a presses down on the arm 12a-1, the valve spring 17a contracts, causing the valve element 12a to rotate around the shaft 22a. When the valve element 12a rotates, the inlet 30a opens, connecting the pressure chamber 11a to the liquid flow chamber 10a and filling the pressure chamber 11a with liquid. When the inlet 30a opens, a negative pressure is generated by the negative pressure spring 13a, and the pressure of the liquid ejection head 200 is adjusted. In the same manner as the low pressure side, the pressure chamber 11b on the high pressure side and the liquid flow chamber 10b-1 are connected to each other, and the pressure in the liquid ejection head 200 is adjusted.

[0017] In the manufacturing process of a liquid ejection head, for example, a liquid such as ink is supplied from pressure control unit 100 to liquid ejection unit 101 using the liquid supply system shown in Fig. 1 to inspect the ejection operation, etc. After the inspection is completed, a cleaning liquid is supplied to pressure control unit 100 and liquid ejection unit 101 to replace the ink or other liquid with the cleaning liquid. Finally, air is supplied to pressure control unit 100 and liquid ejection unit 101 to discharge the cleaning liquid and dry the interior.

[0018] 5 is a schematic diagram showing a state in which the cleaning liquid inside the pressure control unit 100 has been replaced with air. Air is supplied into the pressure control unit 100 by suction using a pump from the downstream side of the pressure control unit 100. In FIG. 5, the black arrow indicates the suction direction. By supplying air into the pressure control unit 100, the cleaning liquid inside the pressure control unit 100 is replaced with air. Fig. 6 is an enlarged view of the portion indicated by A in Fig. 5. There is a gap 18 at the boundary between the pressure-receiving plate 14a and the flexible member 16a, and cleaning liquid remains in this gap 18. If the amount of liquid remaining in the gap 18 can be reduced, it is possible to suppress an increase in humidity after packaging the liquid ejection head 200, and reduce the risk of substrate corrosion.

[0019] (First embodiment) Figure 7 is a schematic diagram showing the appearance of a pressure control unit according to a first embodiment of the present invention. The pressure adjustment unit 100 of this embodiment is the same as that shown in Figures 2 to 6, except for the pressure-receiving plate. The same components as those shown in Figures 2 to 6 are given the same reference numerals, and detailed explanations will be omitted. The pressure-receiving plate 24a is provided on the inner surface of the flexible member 16a of the pressure chamber 11a on the low-pressure side. An internal flow path 25 is formed at the boundary between the pressure plate 24a and the flexible member 16a. The internal flow path 25 extends along the boundary along the inner surface of the flexible member 16a and is formed so as to open to the side surface of the pressure plate 24a. The pressure plate 24a is made of a synthetic resin such as polypropylene. The shape of the contact surface of the pressure plate 24a that contacts the flexible member 16a is different from that of the pressure plate 14a shown in Figures 2 to 6. Note that while Figure 7 only shows the pressure plate 24a on the low-pressure side, a plate similar to the pressure plate 24a is also provided on the high-pressure side, forming an internal flow path.

[0020] 8 is a top view of the pressure plate 24a. The pressure plate 24a has a contact surface 24a-1 that contacts the flexible member 16a. A plurality of recesses 1 are formed over the entire contact surface 24a-1, and a welding portion 20 is provided in the center of the contact surface 24a-1 for fixing it to the inner surface of the flexible member 16a. Here, the contact surface refers to the entire surface that contacts the inner surface of the flexible member 16a, including the recesses. Each recess 1 and the inner surface of the flexible member 16a form an internal flow path 25. Here, the multiple recesses 1 are multiple grooves extending parallel to one another in the same direction. Pressure plate 24b has the same structure as pressure plate 24a. These pressure plates 24a, 24b are welded to case 5 together with flexible members 16a, 16b. For example, after pressure plates 24a, 24b are welded to flexible members 16a, 16b, respectively, flexible members 16a, 16b are welded to case 5. Although the welding portion 20 of the pressure-receiving plate 24a is welded to the flexible member 16a, instead, a part of the pressure-receiving plate 24a (the part corresponding to the welding portion 20) may be adhered to the flexible member 16a using an adhesive that is resistant to liquids such as ink and cleaning fluids.

[0021] FIG. 9 is a partial cross-sectional view of the pressure-receiving plate 24a taken along line CC in FIG. 8. As shown in FIG. 9, the width of the recess 1 is W1, the groove depth of the recess 1 is D, and the width of the contact surface 24a-1 between two adjacent recesses 1 is W2. When the flexible member 16a contacts the bottom surface and sidewall of the recess 1, liquid remains in the gap formed at the contact area. To prevent this liquid from remaining, it is preferable that W1≦D. This relationship makes it difficult for the flexible member 16a to contact the bottom surface and sidewall of the recess 1. In this embodiment, for example, the width W1 is 0.8 mm and the depth D is 1.0 mm.

[0022] In order to reduce the amount of liquid remaining in the gap 18 (see FIG. 6 ) between the inner surface of the flexible member 16a and the contact surface 24a-1 of the pressure-receiving plate 24a, it is preferable that the width W2 of the contact surface 24a-1 be as narrow as possible. In this embodiment, for example, the width W2 is set to 0.5 mm. Furthermore, the smaller the area of ​​the contact surface 24a-1, the more likely it is that the amount of liquid remaining in the gap 18 will be reduced. To reduce the area of ​​the contact surface 24a-1, the corners formed by the sidewall of the recess 1 and the contact surface 24a-1 may be chamfered. Chamfering the corners reduces the area of ​​the contact surface 24a-1, further reducing the amount of liquid remaining in the gap 18.

[0023] FIG. 10 is a cross-sectional view showing the cross-sectional configuration of the pressure control unit 100 taken along line BB in FIG. 7. FIG. 10 also shows an enlarged view of the portion indicated by B. As shown in FIG. 10, the pressure-receiving plate 24a is provided on the inner surface of the flexible member 16a of the low-pressure pressure chamber 11a, and the pressure-receiving plate 24b is provided on the inner surface of the flexible member 16b of the high-pressure pressure chamber 11b. The pressure-receiving plate 24a and the pressure-receiving plate 24b are identical. The recess 1 of the pressure-receiving plate 24a and the inner surface of the flexible member 16a form an internal flow path 25, and the flexible member 16a is not in close contact with the bottom surface or side walls of the recess 1 of the pressure-receiving plate 24a. Similarly, the recess 1 of the pressure-receiving plate 24b and the inner surface of the flexible member 16b form the internal flow path 25, and the flexible member 16b is not in close contact with the bottom surface or side walls of the recess 1 of the pressure-receiving plate 24b.

[0024] FIG. 11 is a schematic diagram showing a state in which the pressure control unit 100 has been filled with liquid. FIG. 11 shows a cross section of the pressure control unit 100 taken along line BB in FIG. 7, and also shows an enlarged partial view of the portion indicated by B. In the example of FIG. 11, liquid is filled into the pressure chambers 11a, 11b using the same principle as in the filling example of FIG. 4. At this time, the liquid penetrates not only into the gap 18 but also into the internal flow path 25 at the boundary between the pressure-receiving plates 24a, 24b and the flexible members 16a, 16b.

[0025] Fig. 12 is a schematic diagram showing a state in which the cleaning liquid in the pressure control unit 100 has been replaced with air. Fig. 12 shows a cross section of the pressure control unit 100 taken along line BB in Fig. 7. Fig. 13 is a partial enlarged view of the portion indicated by B in Fig. 12. In the example of Fig. 12, the cleaning liquid in the pressure chambers 11a and 11b is replaced with air using the same principle as in the replacement example of Fig. 5. As shown in Figure 13, the flexible member 16a is not in close contact with the bottom surface and side walls of the recess 1 of the pressure-receiving plate 24a. Similarly, the flexible member 16b is not in close contact with the bottom surface and side walls of the recess 1 of the pressure-receiving plate 24b. This allows air to flow through the internal flow path 25, allowing the cleaning liquid to be discharged from the internal flow path 25. On the other hand, the contact surfaces 24a-1 and 24b-1 of the pressure-receiving plates 24a and 24b are in close contact with the flexible members 16a and 16b, making it difficult for air to pass through the gap 18. This causes the cleaning liquid to remain in the gap 18.

[0026] According to the pressure control unit 100 of this embodiment, by providing the internal flow path 25, it is possible to discharge a portion of the liquid remaining at the boundary between the pressure-receiving plates 24a, 24b and the flexible members 16a, 16b. This reduces the amount of remaining liquid, improving the ease of removing the liquid. In this way, the ease of removing the liquid inside the pressure control unit 100 is improved, which suppresses an increase in humidity after packaging the liquid ejection head 200 and reduces the risk of substrate corrosion.

[0027] 8, the recesses 1 form a plurality of grooves that extend parallel to one another in the same direction, but the present invention is not limited to this. Modified examples of the pressure plate 24a will be described below. 14 is a top view of a pressure-receiving plate 24a of a first modified example. The pressure-receiving plate 24a of this modified example has a plurality of cross-shaped grooves on the abutment surface 24a-1. Specifically, a plurality of first grooves 1a-1 extending parallel to one another in a first direction (e.g., the X-axis direction) and a plurality of second grooves 1a-2 extending parallel to one another in a second direction (e.g., the Y-axis direction) intersecting the first direction are formed on the abutment surface 24a-1. The plurality of first grooves 1a-1 and the plurality of second grooves 1a-2 intersect with one another. According to the pressure-receiving plate 24a of this modification, the internal flow paths are formed in a cross direction (first and second directions), so the number of directions in which air flows into the boundary between the pressure-receiving plate 24a and the flexible member 16a increases compared to the configuration shown in Fig. 8. Therefore, liquid that has entered the internal flow paths can be efficiently discharged, improving drying efficiency.

[0028] FIG. 15(a) is a top view of a pressure plate 24a of a second modified example. FIG. 15(b) is a cross-sectional view of the pressure plate 24a taken along line DD in FIG. 15(a). FIG. 15(c) is an enlarged perspective view of the periphery of the cross section taken along line DD in FIG. 15(a). FIG. 15(b) shows the pressure plate 24a in contact with the flexible member 16a. The pressure plate 24a of this modified example has multiple through holes 22 in addition to the cross-shaped grooves 1a-1 and 1a-2 shown in FIG. 14. Each through hole 22 penetrates the pressure plate 24a in the thickness direction and communicates with an internal flow path 25 formed by the grooves 1a-1 and 1a-2 and the inner surface of the flexible member 16a. Here, eight through holes 22 are provided to surround the welded portion 20, but this is not a limitation. The number and arrangement of the through holes 22 can be changed as appropriate. According to the pressure-receiving plate 24a of this modified example, liquid that has entered the internal flow path 25 can be discharged from the through-holes 22, and therefore drying efficiency can be further improved compared to the one shown in FIG.

[0029] 16 is a top view of a pressure-receiving plate 24a of a third modified example. The pressure-receiving plate 24a of this modified example has a plurality of grooves 1b on the abutment surface 24a-1. The plurality of grooves 1b are formed radially from the center of the pressure-receiving plate 24a. According to the pressure-receiving plate 24a of this modified example, the internal flow paths 25 are formed in multiple directions, so the number of directions in which air can flow into the boundary between the pressure-receiving plate 24a and the flexible member 16a increases compared to the example shown in Fig. 8. Therefore, liquid that has entered the internal flow paths 25 can be efficiently discharged, improving drying efficiency. In addition, compared to the case where minute grooves are formed as shown in FIGS. 14 and 15, there is no need to prepare a complex molding die, and therefore manufacturing costs can be reduced.

[0030] The configurations of the pressure-receiving plate 24a shown in Figures 8 and 14 to 16 can be combined as appropriate. For example, the through-hole 22 shown in Figure 15 can be applied to the pressure-receiving plate 24a shown in Figures 8 and 16.

[0031] (Second embodiment) Fig. 17(a) is a top view of a pressure-receiving plate used in a pressure control unit according to a second embodiment of the present invention. Fig. 17(b) is a cross-sectional view of the pressure-receiving plate taken along line EE in Fig. 17(a). Fig. 17(b) shows a state in which the pressure-receiving plate 34a is in contact with the inner surface of the flexible member 16a. The pressure control unit of this embodiment has the same structure as the pressure control unit of the first embodiment, except for the pressure-receiving plate 34a.

[0032] As shown in Figures 17(a) and 17(b), the pressure-receiving plate 34a has a first surface 34a-1 facing the inner surface of the flexible member 16a. The first surface 34a-1 does not have the recesses (grooves) described in the first embodiment, but instead has a plurality of protrusions 26 welded to the flexible member 16a. The plurality of protrusions 26, the first surface 34a-1, and the inner surface of the flexible member 16a form an internal flow path 35. The internal flow path 35 extends along the boundary between the pressure-receiving plate 34a and the flexible member 16a, along the inner surface of the flexible member 16a, and is formed to open to a side surface of the pressure-receiving plate 34a. The multiple protrusions 26 are formed independently of one another. The multiple protrusions 26 are arranged in a matrix at a predetermined interval. Here, the predetermined interval is preferably equal to or less than the height of the protrusions 26. In this case, for the same reason as the relationship of the recess 1 (W1≦D) described in the first embodiment, it becomes difficult for the flexible member 16a to adhere closely to the side surface of the protrusions 26 or the first surface 34a-1. The height of the protrusions 26 is the height from the first surface 34a-1 to the top of the protrusions 26. Each protrusion 26 is cylindrical and has the same height. Note that the shape of the protrusions 26 is not limited to a cylindrical shape. The shape of the protrusions 26 may be other shapes, such as a prismatic shape. The number and arrangement of the protrusions 26 can also be changed as appropriate.

[0033] According to the pressure control unit of this embodiment, the first surface 34a-1 of the pressure-receiving plate 34a is welded to the inner surface of the flexible member 16a by the protrusion 26. Therefore, the gap 18 described in the first embodiment does not occur at the boundary between the pressure-receiving plate 34a and the flexible member 16a. Furthermore, when cleaning the pressure control unit, cleaning liquid enters the internal flow path 35. However, as in the first embodiment, the liquid that has entered the internal flow path 35 can be drained. Therefore, compared to the first embodiment, the amount of liquid remaining at the boundary can be further reduced by the amount of the gap 18 not occurring, further improving the removability of the liquid. Therefore, an increase in humidity after packaging the liquid ejection head 200 can be further suppressed, and the risk of substrate corrosion can be reliably reduced.

[0034] Furthermore, even if the entire first surface 34a-1 is welded to the inner surface of the flexible member 16a without providing the protrusion 26, the gap 18 will not be created. However, tension is always applied to the flexible member 16a by the negative pressure spring 13a, and large stress is applied to the welded portion of the flexible member 16a with the pressure-receiving plate 34a, especially to the edge of the pressure-receiving plate 34a. This may cause damage to the flexible member 16a. In contrast, in this embodiment, the pressure-receiving plate 34a is welded to the flexible member 16a at the multiple protrusions 26, which disperses the stress generated in the flexible member 16a, thereby preventing the flexible member 16a from being damaged.

[0035] In the pressure control unit of this embodiment, the pressure-receiving plate 34a may have the through-hole described in the first embodiment. In this case, the through-hole communicates with the internal flow path 35. Alternatively, the plurality of protrusions 26 may be bonded to the inner surface of the flexible member 16a using an adhesive that is resistant to liquids such as ink and cleaning fluids. Furthermore, some of the multiple protrusions 26 may be configured to abut against the inner surface of the flexible member 16a without being welded or bonded. For example, the central protrusion 26 may be welded or bonded to the flexible member 16a, and the remaining protrusions 26 may abut against the inner surface of the flexible member 16a.

[0036] The multiple protrusions 26 may be provided on the inner surface of the flexible member 16a, rather than on the pressure-receiving plate 34a. In this case, the multiple protrusions 26, the first surface 34a-1, and the inner surface of the flexible member 16a form the internal flow path 35. The multiple protrusions 26 are formed independently of one another and are arranged, for example, in a matrix at a predetermined interval. The predetermined interval is preferably equal to or less than the height of the protrusions 26. The multiple protrusions 26 may be welded or bonded to the first surface 34a-1 of the pressure-receiving plate 34a. Some of the multiple protrusions 26 may abut against the first surface 34a-1 of the pressure-receiving plate 34a without being welded or bonded. In the above case, the flexible member 16a may be a multi-layered film made by bonding together a first film on which a plurality of protrusions 26 are formed and a weldable second film such as polypropylene.

[0037] A method for drying the pressure control unit of the first and second embodiments described above will now be described. After inspecting the discharge operation, etc., the inside of the pressure chamber is cleaned with a cleaning liquid. After cleaning, a pump is used to suck liquid from the outlet, and the inside of the pressure chamber and the internal flow path are dried. In these steps, the liquid supply system shown in FIG. 1 can be used. [Explanation of symbols]

[0038] 11a Pressure chamber 16a Flexible member 24a Pressure plate 25 Internal flow path 30a Inlet 31a Outlet 32a Valve member

Claims

1. A pressure control unit having a pressure chamber capable of containing a liquid, an inlet for allowing the liquid to flow into the pressure chamber, and an outlet for allowing the liquid to flow out of the pressure chamber, wherein at least a portion of a wall forming the pressure chamber is formed from a flexible member, a pressure receiving plate provided on the inner surface of the flexible member and displaced toward the inside and outside of the pressure chamber; a valve member that opens and closes the inlet in response to displacement of the pressure plate; an internal flow path extending along the inner surface of the flexible member at the boundary between the pressure plate and the flexible member and opening to a side surface of the pressure plate; A pressure control unit characterized in that the flexible member has a plurality of convex portions on its inner surface, and the convex portions, the inner surface, and a first surface of the pressure plate facing the inner surface form the internal flow path.

2. The pressure control unit according to claim 1, wherein the plurality of protrusions are welded or bonded to the first surface of the pressure-receiving plate.

3. 3. The pressure control unit according to claim 1, further comprising at least one through hole penetrating the pressure plate in a thickness direction, the through hole communicating with the internal flow path.

4. A pressure control unit according to any one of claims 1 to 3; a recording element substrate that ejects liquid; A liquid ejection head, wherein liquid is supplied to the recording element substrate via the pressure control unit.

5. A method for drying a pressure control unit according to any one of claims 1 to 3, comprising: A method for drying a pressure control unit, comprising: cleaning the inside of the pressure chamber with a cleaning liquid; and then using a pump to suck the cleaning liquid through the outlet, thereby drying the inside of the pressure chamber and the internal flow path.

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