Liquid ejection head, its manufacturing method and liquid ejection device

Abstract

To provide a liquid discharge head capable of suppressing mixing of different kinds of liquids to be discharged.SOLUTION: A liquid discharge head 20 having discharge ports 3a, 3b, and constituted by joining a silicon substrate 1 to a support substrate 2, is provided with channels 5a, 5b through which different kinds of liquids flow through a joint area of the silicon substrate 1 and the support substrate 2, and a space 7 inside a bulkhead opened on the joint area of the silicon substrate 1 and the support substrate 2 is formed inside the bulkhead 6 separating the channels 5a, 5b, and the internal pressure in the space 7 inside the bulkhead is set lower than a liquid pressure in the channels 5a, 5b.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a liquid ejection head constructed by bonding a plurality of substrates, a manufacturing method thereof, and a liquid ejection apparatus using the liquid ejection head. [Background technology]

[0002] Some liquid ejection heads that eject liquid from ejection ports have multiple ejection ports and eject different types of liquid from each ejection port. One example is an inkjet recording head that is used in an inkjet recording device and ejects multiple colors of recording liquid, i.e., ink. In such a liquid ejection head, it is necessary to suppress the mixing of different types of liquid to be ejected. However, in a liquid ejection head in which substrates are stacked and a liquid flow path is formed thereon, different types of liquid may be mixed through defects such as gaps that occur between the substrates. In the case of an inkjet recording head, this means that inks of different colors are mixed before being ejected, resulting in a decrease in the recording image quality. Patent Document 1 discloses that a separation groove is provided in a partition wall that separates the flow paths for each type of liquid, and a sealant is injected into this separation groove to prevent the penetration and diffusion of liquid from the gap between the substrates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-148926 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, gaps can occur between the substrates that make up the liquid ejection head due to deterioration over time of the sealant injected into the separation groove, and there is still a risk of different types of liquid to be ejected becoming mixed together.

[0005] An object of the present invention is to provide a liquid ejection head capable of preventing mixing of different types of liquid to be ejected, such as inks of different colors, a manufacturing method thereof, and a liquid ejection device equipped with such a liquid ejection head. [Means for solving the problem]

[0006] The liquid ejection head of the present invention includes an ejection port through which liquid is ejected, No. 1 Substrate and the second board Joint was done composition have A liquid ejection head, No. 1 Substrate and the second board a first flow path penetrating the joint surface between the first and second flow paths through which a liquid different from the liquid flowing through the first flow path passes; provided on at least one of the first substrate and the second substrate, Inside the partition wall separating the first flow path and the second flow path Separated Intra-wall space A recess that opens onto the joining surface And, the partition wall space extends along a direction in which the first flow path and the second flow path extend, The internal pressure of the partition space is lower than both the pressures of the liquid in the first flow path and the second flow path. Effect of the Invention

[0007] According to the present invention, it is possible to prevent different types of liquid to be ejected from mixing in the liquid ejection head. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a configuration of a liquid ejection head. [Diagram 2] 1 is a diagram showing a liquid ejection head according to a first embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram showing a liquid ejection head according to a second embodiment. [Figure 4] FIG. 13 is a diagram showing a liquid ejection head according to a third embodiment. [Diagram 5] FIG. 13 is a diagram showing a liquid ejection head according to a fourth embodiment. [Figure 6] FIG. 13 is a diagram showing a liquid ejection head according to a fifth embodiment. [Figure 7] FIG. 4 is a diagram illustrating an example of a pressure reduction mechanism. [Figure 8] FIG. 13 is a diagram showing a liquid ejection head according to a sixth embodiment. [Figure 9] FIG. 13 is a diagram showing a liquid ejection head according to a seventh embodiment. [Figure 10] FIG. 13 is a diagram showing a liquid ejection head according to an eighth embodiment. [Figure 11] FIG. 1 is a perspective view showing a liquid ejection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, embodiments of the present invention will be described with reference to the drawings. The embodiments described below do not limit the present invention, and the respective features of multiple embodiments can be combined.

[0010] Before describing the liquid ejection head according to the present invention, a general configuration of a liquid ejection head will be described. FIG. 1 shows the configuration of one example of a general liquid ejection head, in which FIG. 1(a) is a partially cutaway perspective view of the liquid ejection head, and FIG. 1(b) is a schematic cross-sectional view of the main part of the liquid ejection head. The liquid ejection head 20 shown in FIG. 1 ejects two different types of liquid, for example, inks of different colors, from each ejection port, and is configured by bonding a silicon substrate 1 and a support substrate 2. Since the silicon substrate 1 and the support substrate 2 are bonded, it can be said that the liquid ejection head 20 is configured from two substrates, but the support substrate 2 itself can also be configured by bonding a plurality of substrates. In that case, the liquid ejection head 20 is configured by stacking and bonding three or more substrates.

[0011] In FIG. 1(a), the left-right direction is the X direction, the direction in which the silicon substrate 1 and the support substrate 2 are joined is the Z direction, and the direction perpendicular to both the X direction and the Z direction is the Y direction. If two different types of liquid are the first liquid and the second liquid, in the example shown here, the ejection port 3a for the first liquid is arranged on the left side in the X direction, and the ejection port 3b for the second liquid is arranged on the right side. In reality, a plurality of ejection ports 3a for the first liquid are provided and arranged along the Y direction, and similarly a plurality of ejection ports 3b for the second liquid are provided and arranged along the Y direction. During normal use of the liquid ejection head 20, the ejection ports 3a and 3b are directed downward in the direction of gravity, so the downward direction in the Z direction in the figure is the direction of gravity. The silicon substrate 1 is arranged below the support substrate 2 in the Y direction in the figure. Furthermore, a plurality of recording elements 4, which are, for example, electrothermal converters, are formed on one surface of the silicon substrate 1 (the lower surface in the figure). The support substrate 2 is joined to the other surface of the silicon substrate 1. A protective layer 31 is provided on one surface of the silicon substrate 1, and the recording element 4 is covered by the protective layer 31. Furthermore, an ejection port forming member 32 in which ejection ports 3a and 3b are formed is provided on one surface of the silicon substrate 1. The ejection ports 3a and 3b are each disposed at a position facing the recording element 4, and the area sandwiched between the ejection port 3a and the recording element 4 is a pressure chamber 34a for the first liquid, and the area sandwiched between the ejection port 3b and the recording element 4 is a pressure chamber 34b for the second liquid. By supplying liquid to the pressure chambers 34a and 34b and driving the recording element 4 in this state, the liquid in the pressure chambers 34a and 34b is, for example, bubbled, and the energy of the bubbles causes the liquid to be ejected as droplets from the ejection ports 3a and 3b.

[0012] In order to supply the liquid to be ejected to the pressure chambers 34a and 34b, flow paths are provided in the support substrate 2 and the silicon substrate 1. In the liquid ejection head 20 shown here, the through flow paths 21a and 23a provided for each ejection port 3a and penetrating the silicon substrate 1 are connected to the pressure chamber 34a of the first liquid, and the liquid is supplied to the pressure chamber 34a from one of the through flow paths 21a and 23a. The liquid not ejected from the ejection port 3a is collected from the other of the through flow paths 21a and 23a. This allows a constant flow of liquid to be formed in the pressure chamber 34a. The through flow paths 21a and 23a for each ejection port 3a are respectively connected to flow path grooves 22a and 24a formed in the support substrate 2 in common to the ejection ports 3a and extending in the Y direction. Similarly, the through-flow passages 21b and 23b penetrating the silicon substrate 1 are connected to the pressure chamber 34b for the second liquid, and the through-flow passages 21b and 23b communicate with the flow grooves 22b and 24b formed in the support substrate 2. For the first liquid, the through-flow passage 21a and the flow groove 22a form a single continuous flow passage 5a as a whole, and the through-flow passage 23a and the flow groove 24a also form a single continuous flow passage 25a as a whole, and these flow passages 5a and 25a penetrate the bonding surface between the silicon substrate 1 and the support substrate 2. Similarly, for the second liquid, the through-flow passage 21b and the flow groove 22b form a flow passage 5b, and the through-flow passage 23b and the flow groove 24b also form a flow passage 25b, and the flow passages 5b and 25b penetrate the bonding surface between the silicon substrate 1 and the support substrate 2. When viewed from the bonding surface, the silicon substrate 1 and the support substrate 2 can be said to be substrates located on both sides of the bonding surface. In the following description, it is assumed that the flow paths 5a and 5b are adjacent to each other via the partition wall 6 in the liquid ejection head 20. Since the flow paths 5a and 5b are adjacent to each other via the partition wall 6, one of them is the first flow path in the present invention, and the other is the second flow path. The partition wall 6 is composed of a partition wall portion 16 that separates the through-flow paths 21a and 21b in the silicon substrate 1, and a partition wall portion 26 that separates the flow path grooves 22a and 22b in the support substrate 2. FIG. 1(b) shows the main part of the liquid ejection head 20, including the ejection ports 3a and 3b, the flow paths 5a and 5b, and the partition wall 6.

[0013] Both the flow path 5a for the first liquid and the flow path 5b for the second liquid pass through the joint surface between the silicon substrate 1 and the support substrate 2. If there is no leakage or penetration of liquid through the joint surface between the silicon substrate 1 and the support substrate 2, more specifically, through the joint surface between the partition parts 16 and 26, the first liquid and the second liquid will not mix. In reality, when there is a defect such as a poor joint, the first liquid and the second liquid may mix due to leakage or penetration through the joint surface between the silicon substrate 1 and the support substrate 2. If the first liquid and the second liquid mix, for example, if black ink is mixed with an ink of a high brightness color, the recording quality will decrease when recording is performed by ejecting the ink of high brightness. Therefore, in the liquid ejection head 20, a partition space 7 that opens to the joint surface between the silicon substrate 1 and the support substrate 2 is formed inside the partition 6, and the internal pressure of the partition space 7 is made lower than both of the liquid pressures in the flow paths 5a and 5b. Even if liquid permeates through the joint surface between the silicon substrate 1 and the support substrate 2, the internal pressure of the partition space 7 is lower than the pressure of the liquid in the flow paths 5a and 5b, so the permeating liquid is drawn into the partition space 7 and blocked there. In this way, the liquid ejection head 20 prevents the first liquid and the second liquid from mixing in the flow paths 5a and 5b. Hereinafter, an embodiment of a liquid ejection head according to the present invention will be described. Note that when both the first liquid and the second liquid flow into the partition space 7, these liquids will mix together, but the mixed liquid in the partition space 7 will not be ejected from the ejection ports 3a and 3b, so there is no problem of a decrease in recording quality.

[0014] (First embodiment) FIG. 2 shows a liquid ejection head according to a first embodiment of the present invention. FIG. 2(a) is a schematic cross-sectional view showing a main part of the liquid ejection head according to the first embodiment, and FIG. 2(b) is a cross-sectional view taken along line aa in FIG. 2(a). FIG. 2(a) shows the same range as that shown in FIG. 1(b) in the liquid ejection head. An intra-partition space 7 is formed inside the partition portion 26 on the support substrate 2 side, and the intra-partition space 7 is formed so as to reach the bonding surface between the silicon substrate 1 and the support substrate 2. That is, the intra-partition space 7 opens to the support substrate 2 side at the bonding surface between the silicon substrate 1 and the support substrate 2. As shown in FIG. 2(b), the intra-partition space 7 extends in the Y direction along the flow channel grooves 22a, 22b at a position that is the middle of the flow channel grooves 22a, 22b. The intra-partition space 7 is sealed, and the internal pressure of the intra-partition space 7 is lower than both the pressures of the liquid in the flow channels 5a, 5b. As a result, even if there is a minute defect that connects flow paths 5a and 5b on the bonding surface between silicon substrate 1 and support substrate 2, the liquid that permeates through this defect is drawn into partition space 7 and blocked there. Mixing of the liquid flowing through flow path 5a and the liquid flowing through flow path 5b can be suppressed.

[0015] Next, a method for manufacturing the liquid ejection head shown in FIG. 2(a) and FIG. 2(b) will be described. A silicon substrate 1 on which the through-flow paths 21a, 21b, 23a, and 23b are already formed, and a support substrate 2 on which the flow paths 22a, 22b, 24a, and 24b are already formed are prepared. A positive photoresist is applied to the surface of the support substrate 2 that will be bonded to the silicon substrate 1, and an etching mask is formed by exposing the surface to light in the shape shown in FIG. 2(b) and developing the surface. Next, the support substrate 2 is dry-etched using plasma to form an inner partition space 7 from the bonded surface to the silicon substrate 1 toward the inside of the support substrate 2. By utilizing the microloading effect of dry etching, the inner partition space 7 can be formed and the flow paths 22a, 22b, 24a, and 24b can be formed at the same time. Thereafter, the silicon substrate 1 and the support substrate 2 are vacuum-bonded in an environment of, for example, 100 Pa (absolute pressure) or less, to assemble the liquid ejection head. Vacuum bonding refers to bonding under a pressure lower than atmospheric pressure. Since liquid ejection heads are generally used at atmospheric pressure (0.1013 MPa) and the pressure in each of the flow paths 5a, 5b is considered to be higher than atmospheric pressure, the pressure in the sealed space 7 within the partition is certainly lower than the pressure of the liquid in the flow paths 5a, 5b.

[0016] 2(c) and 2(d) show another example of the liquid ejection head of the first embodiment. In the first embodiment, the partition space 7 may be provided in the partition portion 16 on the silicon substrate 1 side, not on the support substrate 2 side, as shown in FIG. 2(c), so long as it opens to the bonding surface between the silicon substrate 1 and the support substrate 2. Furthermore, as shown in FIG. 2(d), it is also possible to form the partition space 7 so as to span both the silicon substrate 1 and the support substrate 2 across the bonding surface. In the above description, dry etching is used when forming the partition space 7 in the support substrate 2, which opens to the bonding surface, but dry etching can also be used when forming the partition space 7 in the silicon substrate 1. Furthermore, as a processing method for forming the partition space 7 in the silicon substrate 1 and the support substrate 2, wet etching and other processing methods can be used in addition to dry etching. As a method for bonding the silicon substrate 1 and the support substrate 2, a method other than vacuum bonding can be used, and as a specific bonding method, a method in which a bonding material such as an adhesive is interposed can be used, or a direct bonding method without using an adhesive can be used.

[0017] Second Embodiment FIG. 3 shows a liquid ejection head according to a second embodiment of the present invention, in which FIG. 3(a) is a cross-sectional view of the liquid ejection head, and FIG. 3(b) is a cross-sectional view taken along line bb in FIG. 3(a). The liquid ejection head according to the second embodiment is the liquid ejection head shown in FIG. 2(a) and FIG. 2(b) provided with a liquid reservoir 8 communicating with the partition space 7. The liquid reservoir 8 is a space larger than the partition space 7, and is provided inside the support substrate 2 so as to open to the bonding surface between the silicon substrate 1 and the support substrate 2. The partition space 7 and the liquid reservoir 8 are sealed as a whole, and the internal pressure is lower than the pressure of the liquid in the flow paths 5a and 5b. The liquid that flows into the partition space 7 and is blocked there due to the low pressure in the partition space 7 then flows to the liquid reservoir 8 and is stored there. In the liquid ejection head of the first embodiment, the effect of suppressing the mixing of liquids is lost when the partition space 7 is filled with liquid, but in the second embodiment, the effect of suppressing the mixing of liquids is maintained until not only the partition space 7 but also the liquid storage portion 8 is filled with liquid. Therefore, according to the liquid ejection head of the second embodiment, the effect of suppressing the mixing of different liquids is exerted for a longer period of time. As in the first embodiment, the liquid ejection head of the second embodiment can be assembled by forming the partition space 7 and the liquid storage portion 8 in the support substrate 2 by dry etching, and then vacuum bonding the silicon substrate 1 and the support substrate 2.

[0018] In a liquid ejection head that ejects three or more kinds of liquid, for example, a liquid ejection head that ejects ink of three or four colors, the number of partition walls 6 separating the flow paths of different liquids is two or more, and the number of partition wall spaces 7 is also two or more. In a liquid ejection head having two or more partition wall spaces 7, a liquid reservoir 8 may be provided for each partition wall space 7, or one liquid reservoir 8 may be provided commonly to a plurality of partition wall spaces 7. In the above example, the liquid reservoir 8 is provided in the support substrate 2, but the liquid reservoir 8 may be provided outside the silicon substrate 1 or the support substrate 2 as long as the partition wall spaces 7 and the liquid reservoir 8 are kept sealed as a whole. In addition, the liquid ejection head shown in FIG. 2(c) or FIG. 2(d) may also be provided with a liquid reservoir 8 communicating with the partition wall space 7.

[0019] (Third embodiment) FIG. 4 shows a liquid ejection head according to a third embodiment of the present invention, in which FIG. 4(a) is a cross-sectional view of the liquid ejection head, FIG. 4(b) is a cross-sectional view taken along line cc in FIG. 4(a), and FIG. 4(c) is a cross-sectional view taken along line dd in FIG. 4(b). The line dd extends in the Y direction. The liquid ejection head according to the third embodiment includes a liquid reservoir 8 communicating with the partition space 7, as in the second embodiment, but differs from the second embodiment in that the partition space 7 and the liquid reservoir 8 are provided in the silicon substrate 1. In addition, the width (width along the X direction) of the partition space 7 at the joint surface between the silicon substrate 1 and the support substrate 2 is wider toward the liquid reservoir 8. When the partition space 7, which becomes wider toward the liquid reservoir 8, is formed by dry etching, the silicon substrate 1 is etched away deeper in the wider portion due to the microloading effect during etching. When the liquid ejection head is in use, the silicon substrate 1 is located below the support substrate 2 in the direction of gravity, and therefore the bottom surface of the partition space 7 is formed to be inclined downward in the direction of gravity during use toward the liquid storage portion 8, as shown in Fig. 4(c). The bottom surface of the partition space 7 here refers to the surface of the partition space 7 that is on the lower side in the direction of gravity during use. By inclining the partition space 7 in this way, it becomes possible to efficiently guide the liquid that has flowed into the partition space 7 to the liquid storage portion 8.

[0020] 3, an inclined partition space 7 is provided in silicon substrate 1 which is lower in the direction of gravity than support substrate 2 when the liquid ejection head is in use. Therefore, even if the pressure in partition space 7 is not made lower than the pressure of the liquid in flow paths 5a and 5b, the liquid that has permeated the bonding surface between silicon substrate 1 and support substrate 2 can be blocked by partition space 7 and stored in liquid reservoir 8. Therefore, with regard to the third embodiment, it is not essential that the pressure in partition space 7 be made lower than the pressure of the liquid in flow paths 5a and 5b.

[0021] (Fourth embodiment) In each of the above-mentioned embodiments, the pressure inside the partition space 7 is sufficiently lower than the atmospheric pressure by bonding the silicon substrate 1 and the support substrate 2 by vacuum bonding. However, there are other methods for lowering the internal pressure of the partition space 7 than vacuum bonding, and one of them is to use a pressure reduction mechanism. The pressure reduction mechanism includes a mechanism that reduces the pressure by cooling or adsorbing the gas in the sealed space, and a mechanism that uses a pump to exhaust the gas in the space to the outside. When the latter pressure reduction mechanism is used, the partition space 7 is not sealed because an exhaust pump is connected. FIG. 5 shows a liquid discharge head according to a fourth embodiment of the present invention, in which FIG. 5(a) is a cross-sectional view of the liquid discharge head, and FIG. 5(b) is a cross-sectional view taken along the line ee in FIG. 5(a). The liquid discharge head according to the fourth embodiment is similar to the liquid discharge head according to the second embodiment, but the liquid reservoir 8 is provided outside the support substrate 2, and the liquid reservoir 8 can be cooled by a cooling mechanism 42 consisting of a Peltier element or the like. The partition space 7 and the liquid storage portion 8 are connected by an outlet pipe 41, and the partition space 7, the liquid storage portion 8, and the outlet pipe 41 are entirely sealed. When the liquid storage portion 8 is cooled by the cooling mechanism 42, the pressure of the gas inside the liquid storage portion 8 decreases, and accordingly, the internal pressure of the partition space 7 communicating with the liquid storage portion 8 also decreases. In the liquid ejection head of the fourth embodiment, the pressure in the partition space 7 can be made lower than the pressure of the liquid in the flow paths 5a and 5b by cooling the liquid storage portion 8 by the cooling mechanism 42, and mixing of the first liquid and the second liquid can be suppressed, as in the above-mentioned embodiments.

[0022] In the fourth embodiment, it is also possible to provide the liquid reservoir 8 in the silicon substrate 1 or the support substrate 2 and provide the cooling mechanism 42 therein. In this case, the drawing pipe 41 is not provided. Since the drawing pipe 41 also has a heat insulating function, when the drawing pipe 41 is not provided, a heat insulating structure may be provided separately to prevent the liquid to be discharged from being excessively cooled. In addition, a backflow prevention mechanism such as a backflow prevention valve may be provided at the connection between the partition space 7 and the drawing pipe 41. By providing the backflow prevention mechanism, it is possible to prevent the internal pressure of the partition space 7 from increasing and the liquid in the liquid reservoir 8 from flowing back into the partition space 7 when the cooling mechanism 42 is not operating.

[0023] Fifth embodiment FIG. 6 shows a liquid ejection head according to a fifth embodiment of the present invention, in which FIG. 6(a) is a cross-sectional view of the liquid ejection head, and FIG. 6(b) is a cross-sectional view taken along the line ff in FIG. 6(a). The liquid ejection head according to the fifth embodiment is similar to the liquid ejection head shown in FIG. 2(a) and FIG. 2(b), but is different from the liquid ejection head shown in FIG. 2(a) and FIG. 2(b) in that it includes a pump 9 connected to the partition space 7. The pump 9 communicates with the partition space 7 and sucks in the gas inside the partition space 7 and discharges it to the outside, thereby maintaining the pressure inside the partition space 7 lower than the pressure of the liquid in the flow paths 5a and 5b. The pump 9 is provided, for example, outside the support substrate 2. Although the partition space 7 is not a sealed space due to the provision of the pump 9, the present embodiment can also suppress the first liquid and the second liquid from mixing. In the configuration shown in FIG. 2(c) or 2(d), the pressure in the partition space 7 can be maintained lower than the pressure of the liquid in the flow paths 5a and 5b by connecting the pump 9.

[0024] Sixth embodiment In the liquid ejection head having the liquid storage section 8 communicating with the partition space 7 as shown in the second or third embodiment, the pressure in the partition space 7 can be made lower than the pressure of the liquid in the flow paths 5a and 5b by connecting the pump 9. FIG. 7 is a cross-sectional view for explaining the liquid ejection head of the sixth embodiment, and shows the connection form of the pump 9 to the liquid storage section 8 when the liquid storage section 8 is connected to the partition space 7 via the drawing pipe 41. The pump 9 is connected to the liquid storage section 8 via the piping 44, so that the pump 9 is in communication with the partition space 7, and the partition space 7 is sucked and exhausted via the liquid storage section 8 and the drawing pipe 41. At this time, the liquid stored in the liquid storage section 8 may be sucked by the pump 9 and discharged to the outside. Furthermore, in the one shown in FIG. 7, an opening / closing valve 45 is provided at the position where the piping 44 is attached to the liquid storage section 8, and a sensor 43 is provided inside the liquid storage section 8. When the sensor 43 is a liquid level sensor, the sensor 43 detects that a certain amount of liquid has flowed into the liquid storage section 8 and accumulated therein, and the opening and closing of the on-off valve 45 and the driving of the pump 9 can be controlled. The driving of the pump 9 is controlled, for example, by controlling the on / off of the power supply of the pump 9. When the sensor 43 is a pressure sensor, the driving of the pump 9 can be controlled according to the pressure detected by the sensor 43, and the opening and closing of the on-off valve 45 can be controlled in synchronization with the driving of the pump 9. The driving of the pump 9 can be controlled using a management index other than the liquid level or pressure in the liquid storage section 8, and the driving of the pump 9 can also be controlled by combining a plurality of management indexes. Here, the liquid storage section 8 is connected to the partition inner space 7 via the lead-out pipe 41, but the pump 9 may be connected to the liquid storage section 8 formed in the silicon substrate 1 or the support substrate 2.

[0025] Seventh embodiment When the pump 9 is provided in the liquid discharge head of each of the above-mentioned embodiments, a multi-way valve such as a three-way valve can be provided on the inlet side of the pump 9, i.e., at the position where the pump 9 is connected to the partition space 7 or the liquid storage section 8. FIG. 8 shows a liquid discharge head of a seventh embodiment of the present invention. In FIG. 8(a), when the pump 9 is connected to the partition space 7 via the outlet pipe 41, a multi-way valve 48 is provided in the middle of the outlet pipe 41, and another pipe 47 is connected to the multi-way valve 48. In FIG. 8(b), when the pump 9 is connected to the liquid storage section 8, a multi-way valve 48 is provided between the liquid storage section 8 and the pump 9, and the pipe 47 is also connected to the multi-way valve 48. In both the cases of FIG. 8(a) and FIG. 8(b), the pipe 47 connected to the multi-way valve 48 can be connected to another partition space 7 or liquid storage section 8. By connecting a plurality of intra-partition spaces 7 and liquid reservoirs 8 to the multi-way on-off valve 48, a single pump 9 can communicate with these multiple intra-partition spaces 7 and liquid reservoirs 8, and it becomes possible to perform suction from the multiple intra-partition spaces 7 and liquid reservoirs 8 using the pump 9. In this case, by controlling the opening direction of the multi-way on-off valve 48 based on the pressure or the liquid level in the liquid reservoir 8, suction may be performed from one specific intra-partition space 7 or liquid reservoir 8, or suction may be performed from all intra-partition spaces 7 and liquid reservoirs 8. Furthermore, suction may be performed from multiple intra-partition spaces 7 at one time and from multiple liquid reservoirs 8 at another time.

[0026] As long as at least one of the partition space 7 or the liquid storage section 8 is connected to the multi-way on-off valve 48 provided on the inlet side of the pump 9, the multi-way on-off valve 48 may be connected to a space other than the partition space 7 or the liquid storage section 8, for example, via a pipe 47. For example, when a bubble storage space for storing bubbles generated in the liquid in the flow paths 5a, 5b, etc. is provided in the liquid ejection head, the bubble storage space and the pump 9 may be connected to each other via the multi-way on-off valve 48. In this case, by controlling the opening direction of the multi-way on-off valve 48, it is possible to switch between when the pump 9 communicates with the bubble storage space and when the pump 9 communicates with the partition space 7 or the liquid storage section 8. This makes it possible to switch between sucking out bubbles inside the flow paths 5a, 5b, etc. and drawing liquid into the partition space 7 whose pressure has been reduced by the action of the pump 9.

[0027] Eighth embodiment FIG. 9 is a diagram for explaining a liquid ejection head of an eighth embodiment, in which FIG. 9(a) and FIG. 9(c) are schematic cross-sectional views of the liquid ejection head, FIG. 9(b) is a cross-sectional view taken along line gg in FIG. 9(a), and FIG. 9(d) is a cross-sectional view taken along line hh in FIG. 9(c). In a liquid ejection head, a substrate bonding member 10 may be used to bond a silicon substrate 1 to a support substrate 2. FIG. 9 shows a case in which a substrate bonding member 10 is used to bond a silicon substrate 1 to a support substrate 2 in the liquid ejection head shown in FIG. 2(a) and FIG. 2(b). The substrate bonding member 10 is made of, for example, a dry film. At this time, as shown in FIG. 9(a) and FIG. 9(b), the substrate bonding member 10 is patterned in such a shape that the openings (i.e., the through-flow paths 21a, 21b) in the silicon substrate 1 are removed. In this case, the silicon substrate 1 is not exposed inside the partition space 7, and the partition space 7 can only draw in liquid that permeates through defects present at the interface between the support substrate 2 and the substrate bonding member 10. Therefore, there remains a possibility that the first liquid and the second liquid may be mixed through defects present at the interface between the silicon substrate 1 and the substrate bonding member 10. In the eighth embodiment, as shown in Figs. 9(c) and 9(d), a substrate bonding member 10 having photosensitivity and made into a dry film is tented on the surface of the support substrate 2 used for bonding to the silicon substrate 1. Next, the substrate bonding member 10 is exposed to light in the shape shown in Fig. 9(d) and developed, thereby removing the substrate bonding member 10 not only from the flow channels 22a and 22b but also from the partition wall space 7. As a result, the substrate bonding member 10 is no longer present at the interface between the partition wall space 7 and the substrate 1, and a part of the surface of the silicon substrate 1 is exposed inside the partition wall space 7. It becomes possible to draw in and dam up the liquid that has permeated through the interface between the silicon substrate 1 and the substrate bonding member 10 into the partition wall space 7.

[0028] In this embodiment, the layer of the substrate bonding member 10 may be formed by transfer printing. When the substrate bonding member 10 is removed in accordance with the position of the partition space 7, it is not necessary to completely remove the substrate bonding member 10 in the portion corresponding to the partition space 7, and it is sufficient that at least a part of the surface of the silicon substrate 1 is exposed to the partition space 7 during bonding. In the embodiment described with reference to FIG. 9, the partition space 7 is formed on the side of the support substrate 2, but this embodiment is also applicable to the case where the partition space 7 is formed in the silicon substrate 1. In this case, too, the layer of the substrate bonding member 10 is formed so that at least a part of the surface of the silicon substrate 1 and at least a part of the surface of the support substrate 2 are exposed inside the partition space 7. In the case where the substrate bonding member 10 is used to bond the silicon substrate 1 and the support substrate 2 in a liquid discharge head having a liquid storage section 8 as shown in the second to fourth embodiments, it is sufficient that both the silicon substrate 1 and the support substrate 2 are exposed inside the partition space 7.

[0029] Ninth embodiment FIG. 10 is a diagram for explaining a liquid ejection head according to a ninth embodiment, FIG. 10 being a schematic cross-sectional view of the liquid ejection head, and FIG. 10(b) being a cross-sectional view taken along line ii in FIG. 10(a). When the silicon substrate 1 and the support substrate 2 are bonded using the substrate bonding member 10 as in the eighth embodiment, the substrate bonding member 10 may enter the partition space 7 during bonding depending on the material of the substrate bonding member 10. If the partition space 7 is filled with the substrate bonding member 10, the effect of the present invention of preventing the first liquid and the second liquid from mixing cannot be achieved. Therefore, in the liquid ejection head of the ninth embodiment, a plurality of separation walls 11 are provided inside the partition space 7 to minimize the substrate bonding member 10 from entering the partition space 7. The separation walls 11 have a ridge-like or ridge-like shape extending in the extension direction (Y direction) of the partition space 7 to partially separate the partition space 7. When the separation walls 11 are provided in this manner, the substrate bonding member 10 is less likely to enter the space sandwiched between two adjacent separation walls 11 when the silicon substrate 1 and the support substrate 2 are bonded. By leaving such a space, the function of the partition inner space 7 of drawing in and blocking the permeating liquid is maintained, and mixing of the first liquid and the second liquid can be prevented.

[0030] (Liquid discharge device) The liquid ejection heads of the above-mentioned embodiments are preferably used in a liquid ejection device. FIG. 11 is a perspective view of an example of a liquid ejection device. This liquid ejection device is configured as an inkjet recording device that ejects ink as a liquid from an ejection port to perform recording on a recording medium 53. The liquid ejection device includes a conveying section 51 that conveys the recording medium 53 and a holding section 52 arranged substantially perpendicular to the conveying direction of the recording medium 53, and the liquid ejection head 20 based on the present invention is attached to the lower surface of the holding section 52 so as to face the recording medium 53. The recording medium 53 is, for example, a cut sheet, but may be a continuous roll of paper or the like other than the cut sheet. The liquid ejection head 20 ejects ink of two or more different colors, preferably ink of each color of cyan (C), magenta (M), yellow (Y), and black (K), to enable full-color recording on the recording medium 53. By using the liquid ejection head 20 based on the present invention, this liquid ejection device can perform full-color recording with better image quality on the recording medium 53 because inks of different colors do not mix inside the liquid ejection head 20. [Explanation of symbols]

[0031] 1. Silicon substrate 2 Support substrate 3 outlet 5a,5b,35a,35b,36a,36b,37a,37b flow path 6,26 Bulkhead part 7 Space inside bulkhead 20 Liquid ejection head

Claims

1. A liquid ejection head having an ejection port through which liquid is ejected, the liquid ejection head having a configuration in which a first substrate and a second substrate are joined together, a first flow path through a joint surface between the first substrate and the second substrate, through which a liquid flows; a second flow path through the joint surface through which a liquid different from the liquid flowing through the first flow path flows; a recess provided on at least one of the first substrate and the second substrate, the recess forming an inner partition space inside a partition separating the first flow path and the second flow path and opening on the joining surface; Equipped with the partition wall space extends along a direction in which the first flow path and the second flow path extend, A liquid ejection head, wherein an internal pressure of the partition space is lower than both of pressures of the liquid in the first flow path and pressures of the liquid in the second flow path.

2. The liquid ejection head according to claim 1 , wherein a substrate bonding member for bonding the first substrate and the second substrate on both sides of the bonding surface is disposed on the bonding surface.

3. The liquid ejection head according to claim 1 , wherein at least a part of each of the first substrate and the second substrate on both sides of the joining surface is exposed inside the partition space.

4. The liquid ejection head according to claim 1 , further comprising a liquid reservoir portion communicating with the partition space for storing the liquid that has flowed into the partition space.

5. The liquid ejection head according to claim 4 , wherein a bottom surface of the space within the partition, which is on the lower side in the direction of gravity when the liquid ejection head is in use, is formed so as to be inclined downward in the direction of gravity when the liquid ejection head is in use, toward the liquid storage section.

6. The liquid ejection head according to claim 4 , further comprising a cooling mechanism for cooling the liquid reservoir.

7. The liquid ejection head according to claim 1 , wherein the space within the partition wall is a sealed space.

8. The liquid ejection head according to claim 4 , wherein the partition space and the liquid storage portion together form a sealed space.

9. A liquid ejection head as described in claim 1, wherein in a direction intersecting the direction in which the first flow path and the second flow path extend, the space within the partition is located halfway between the first flow path and the second flow path.

10. The liquid ejection head according to claim 1 , further comprising a pump communicating with the space within the partition wall for suction.

11. a pump that is connected to the liquid reservoir and communicates with the partition inner space to perform suction; A sensor provided in the liquid reservoir; The liquid ejection head according to claim 4 , further comprising: a pump control unit for controlling the pump operation, the pump control unit being configured to control the pump operation.

12. The liquid ejection head according to claim 11 , wherein the pump is provided with a multi-way on-off valve on the inlet side of the pump, so that the pump can communicate with a plurality of the partition spaces.

13. The liquid ejection head according to claim 12 , wherein the multi-way on-off valve also communicates with an air bubble storage space for storing air bubbles generated in the liquid.

14. A liquid ejection head having an ejection port through which liquid is ejected and configured by joining a plurality of substrates, a first flow path through which a liquid flows, the first flow path passing through a joint surface between the plurality of substrates; a second flow path through the joint surface through which a liquid different from the liquid flowing through the first flow path flows; a partition wall space provided inside the partition wall separating the first flow path and the second flow path and opening to the joining surface; a liquid reservoir portion communicating with the partition wall space for storing liquid that has flowed into the partition wall space; Equipped with a liquid ejection head, characterized in that the space within the partition is formed in the substrate, which is located lower in the direction of gravity than the bonding surface when the liquid ejection head is in use, and is inclined downward in the direction of gravity when the liquid ejection head is in use, toward the liquid storage portion.

15. The liquid ejection head according to claim 1 , further comprising a partition wall that partially separates the partition space within the partition space.

16. A liquid ejection head as described in any one of claims 1 to 15, wherein the first flow path and the second flow path are configured to allow inks of different colors to flow through them.

17. A method for manufacturing a liquid ejection head according to claim 7 or 8, comprising the steps of: A method for manufacturing a liquid ejection head, comprising vacuum bonding the first substrate and the second substrate to be disposed on either side of the bonding surface.

18. A liquid ejection head according to any one of claims 1 to 16, a holding portion for holding the liquid ejection head; A liquid ejection device comprising:

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