Liquid discharge head and recording device

Abstract

A flow path member of this head has a plurality of flow path parts stacked together with an adhesive interposed therebetween. The flow path member has a flow path, a plurality of relief grooves, and a plurality of communication holes. The flow path includes a plurality of nozzles. The plurality of relief grooves are positioned between the plurality of layers between the plurality of flow path parts and are spaced apart from the flow path. The plurality of communication holes are connected to the plurality of relief grooves, the communication holes opening in a first outer surface of the flow path member. Each of the plurality of communication holes passes through one or more flow path parts in the direction in which the plurality of flow path parts are stacked and reaches the first outer surface positioned on one side in the stacking direction. First relief grooves between first layers and second relief grooves between second layers are connected to mutually different communication holes, thereby being isolated from each other.

Description

Liquid ejection head and recording device

[0001] The present disclosure relates to a liquid ejection head such as an inkjet head, and a recording apparatus having the liquid ejection head.

[0002] Liquid ejection heads (e.g., inkjet heads) that eject droplets (e.g., ink droplets) toward a recording medium (e.g., paper) are known (see, for example, Patent Documents 1 to 4 listed below). Such liquid ejection heads include a flow path member having a flow path through which liquid flows. The flow path member is formed, for example, by stacking multiple plates with an adhesive interposed therebetween. The flow path is formed by connecting holes (e.g., through holes and recesses) provided in each of the multiple plates through the stacking of the multiple plates.

[0003] In Patent Documents 1 to 4, relief grooves for releasing excess adhesive are provided on the upper or lower surfaces of the plates. In Patent Documents 2 and 4, the relief grooves extend to the edges of the plates, thereby opening to the atmosphere. By opening to the atmosphere, for example, air bubbles generated in the adhesive can be released to the outside of the flow path member. In Patent Document 3, the relief grooves are opened to the atmosphere by through-holes that penetrate the multiple plates in the stacking direction. Note that Patent Document 1 does not describe opening the relief grooves to the atmosphere.

[0004] Japanese Patent Application Laid-Open No. 2005-22088 Japanese Patent Application Laid-Open No. 2005-125768 Japanese Patent Application Laid-Open No. 2006-187967 Japanese Patent Application Laid-Open No. 2009-241392

[0005] A liquid ejection head according to one aspect of the present disclosure includes a flow path member having a plurality of flow path parts laminated together via an adhesive. The flow path member includes a flow path including a plurality of nozzles, a plurality of relief grooves located between the plurality of flow path parts and spaced apart from the flow path, and a plurality of communication holes connected to the relief grooves and opening on a first outer surface of the flow path member. Each of the communication holes penetrates one or more flow path parts in the stacking direction of the plurality of flow path parts and reaches the first outer surface located on one side of the stacking direction. Of the plurality of relief grooves, a first relief groove between first layers and a second relief groove between second layers are connected to different communication holes among the plurality of communication holes, thereby isolating them from each other.

[0006] A recording apparatus according to one aspect of the present disclosure includes the liquid ejection head and a moving unit that moves the liquid ejection head relative to a recording medium, and liquid ejected from the plurality of nozzles lands on the recording medium.

[0007] 1. A side view schematically showing a recording apparatus according to an embodiment. 2. A plan view schematically showing the recording apparatus of FIG. 1. 3. An exploded perspective view of the liquid ejection head of the recording apparatus of FIG. 1, as viewed from the top. 4. A perspective view of a supply member of the liquid ejection head of FIG. 3, as viewed from the bottom. 5. An exploded perspective view of a flow path member of the liquid ejection head of FIG. 3. 6. A top view of the flow path member of FIG. 5. 7. An enlarged view of region VI of FIG. 6. 8. A cross-sectional view including a cross section taken along line VIII-VIII of FIG. 7. 9. A schematic cross-sectional view showing a first example of a path for opening a relief groove to the atmosphere. 10. A schematic cross-sectional view showing a second example of a path for opening a relief groove to the atmosphere. 11. A schematic cross-sectional view showing a third example of a path for opening a relief groove to the atmosphere. 12. A schematic cross-sectional view showing a fourth example of a path for opening a relief groove to the atmosphere. 13. A schematic top view showing a fifth example of a path for opening a relief groove to the atmosphere. 14. A plan view showing a specific example of the shape of the relief groove. 15. A partial enlarged view of FIG. 14.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The drawings used in the following description are schematic. Therefore, for example, the dimensional ratios in the drawings do not necessarily correspond to the actual ones. Furthermore, the dimensional ratios may not match between drawings. Certain shapes and / or dimensions may be exaggerated, and details may be omitted. However, the above does not deny that the actual shapes and / or dimensions may be as shown in the drawings, or that features of shapes and / or dimensions may be extracted from the drawings.

[0009] (Overview of the embodiment) Fig. 1 is a side view that schematically shows a printer 1 (an example of a recording apparatus) according to the embodiment. Fig. 2 is a top view of the printer 1. The printer 1 and a head 2 (an example of a liquid ejection head) described later may be used in any orientation. However, for convenience, the upper side along the plane of Fig. 1 is taken to be the actual upper side, and terms such as upper surface and lower surface may be used.

[0010] The printer 1 has at least one head 2 (multiple in the illustrated example). The head 2 ejects droplets (e.g., ink droplets) toward a print sheet P (an example of a recording medium) located below the head 2. In this way, printing is performed, for example.

[0011] 8 is a cross-sectional view showing a part of the flow path member 3 that constitutes the lower surface (hereinafter sometimes referred to as the "ejection surface 3a") of the head 2. The up-down direction in this figure corresponds to the up-down direction in FIG.

[0012] The flow path member 3 has a flow path 11 that contains a liquid (e.g., ink). The flow path 11 has a plurality of nozzles 13 (only one is shown in FIG. 8) that open on the ejection surface 3a. Droplets are ejected from the plurality of nozzles 13 toward the downward direction (-D3 side) in the figure.

[0013] The flow path member 3 is formed by laminating a plurality of flow path parts 15 (15A to 15J) with adhesive 17 (see FIG. 12; not shown in FIG. 8) interposed therebetween. The flow path 11 is formed by connecting holes (for example, through holes and recesses) provided in each of the plurality of flow path parts 15 by laminating the plurality of flow path parts 15 together.

[0014] The space between two adjacent flow path parts 15 (or the boundary from another perspective) is referred to as an interlayer space 19. A relief groove 21 is formed in each of the multiple interlayer spaces 19. From another perspective, the relief groove 21 is formed on the surfaces (upper and / or lower surfaces) of the multiple flow path parts 15 that are joined to each other. The relief groove 21 allows, for example, excess adhesive 17, air bubbles trapped when the multiple flow path parts 15 are stacked, and gas generated when the adhesive hardens to escape. The relief groove 21 is, for example, isolated from the flow path 11 (the two are not connected).

[0015] Unless otherwise specified, "isolated" refers to two cavities (the relief groove 21 and the flow path 11 in the above) being isolated so that no fluid (gas and / or liquid) flows between them. Furthermore, unless otherwise specified, when "isolated" is used with respect to the relief groove 21, it refers to the isolation of the relief groove 21 from other cavities so that no fluid flows between them, even if it is assumed that no excess adhesive 17 is filled in the relief groove 21. The same applies to other cavities connected to the relief groove 21 (for example, the communication hole 23 described below).

[0016] The flow path member 3 has a communication hole 23. The communication hole 23 is connected to the relief groove 21 and opens to a predetermined outer surface of the flow path member 3 (in the illustrated example, the pressure surface 3b opposite the ejection surface 3a). The communication hole 23 contributes to, for example, reducing the likelihood of poor adhesion. Specifically, for example, during the manufacture of the flow path member 3, heating may be performed to harden the adhesive 17. At this time, the gas in the relief groove 21 expands due to the heating. The communication hole 23 allows this expanded gas to escape to the outside of the flow path member 3. As a result, the likelihood of pressurized gas infiltrating the relief groove 21 into its surroundings is reduced.

[0017] 9 is a schematic cross-sectional view showing a first example of a path formed by the relief grooves 21 and the communication holes 23. This diagram is primarily a convenient and schematic diagram for explaining the communication and isolation between the multiple relief grooves 21. Therefore, the shape of the flow path 11 does not reflect the actual shape, etc., as compared to FIG. 8. Also, the number of flow path parts 15 (15K to 15Q) etc. is different from FIG. 8.

[0018] As shown in FIG. 9 , the flow path member 3 has a plurality of communication holes 23 (23L to 23Q). Each communication hole 23 penetrates at least one flow path part 15 in the stacking direction of the plurality of flow path parts 15. Furthermore, the relief groove 21 (first relief groove) of at least one interlayer 19 is connected to a communication hole 23 that is different from the relief groove 21 (second relief groove) of at least another interlayer 19. This isolates the first relief groove and the second relief groove from each other. In the example of FIG. 9 , the relief groove 21 of each of all interlayers 19 (19L to 19Q) is isolated from the relief grooves 21 of the other interlayers 19.

[0019] According to this configuration, it is easy to perform a leak test of the relief groove 21 for, for example, a specific interlayer space 19 or for each of a plurality of interlayer spaces 19. Specifically, for example, the following is performed.

[0020] In the leak test, the amount of gas discharged from the relief groove 21 to the outside of the flow path member 3 is measured. By performing a leak test when bonding multiple flow path parts 15, it is possible to evaluate whether the amount of adhesive 17 is excessive or insufficient. The above method is particularly effective because it is difficult to evaluate whether the amount of adhesive 17 is insufficient from the appearance of the flow path member 3. Being able to evaluate whether the amount of adhesive 17 is excessive or insufficient makes it easier to optimize the amount of adhesive 17. Optimizing the amount of adhesive 17 makes it easier to reduce errors related to the shape of the flow path 11, for example. As a result, printing accuracy is improved, and it is easier to improve image quality.

[0021] In the embodiment, one interlayer 19 (first interlayer) and another interlayer 19 (second interlayer) are connected to separate communication holes 23, and are thereby isolated from each other and open to the outside. Therefore, leak tests can be performed separately between the first interlayer and the second interlayer, and the amount of adhesive 17 between the first and second interlayers can be evaluated separately. This makes it possible to deal with cases where the amount of adhesive 17 differs between interlayers 19 (or between groups of interlayers 19). One factor that may cause the amount of adhesive 17 to differ between interlayers 19 is that the shapes of the flow path parts 15 (e.g., the shapes related to the flow paths 11) that make up each interlayer 19 are different from each other.

[0022] The multiple communication holes 23 extend in the stacking direction of the multiple flow path parts 15 and open at the pressure surface 3b. Therefore, unlike, for example, an embodiment in which the relief grooves 21 reach the outer edge of the flow path part 15 and open to the outside, the positional relationship of the multiple openings that open the multiple relief grooves 21 to the outside (the positional relationship of the multiple communication holes 23 in a plan view) is basically independent of the positional relationship of the multiple interlayer spaces 19 in a cross-sectional view. In other words, the degree of freedom in arranging the multiple communication holes 23 is high. Furthermore, for example, the surface of the flow path member 3 facing the stacking direction of the flow path parts 15 (the ejection surface 3a and the pressure surface 3b) is usually wider than the surfaces to the sides of the stacking direction. Therefore, for example, it is easy to ensure a distance between the multiple communication holes 23 while grouping the multiple communication holes 23 in a specific region (for example, the longitudinal end of the pressure surface 3b).

[0023] From the above, for example, when a device for performing a leak test is configured to connect its measurement flow paths to the communication holes 23, it becomes easy to individually connect a plurality of measurement flow paths to a plurality of communication holes 23. In other words, it becomes easy to separately perform leak tests between the first layer and the second layer. Consequently, as described above, it becomes possible to separately evaluate the excess or deficiency of the adhesive 17 between the first layer and the second layer.

[0024] Furthermore, the flow path member 3 according to the embodiment can achieve various effects other than those related to leak testing. From another perspective, the effects related to the above-described leak testing do not necessarily have to be achieved. For example, if ink in the flow path 11 flows into the relief groove 21 due to a shortage or peeling of the adhesive 17, the relief grooves 21 are isolated from each other, reducing the likelihood of the ink penetrating multiple relief grooves 21. Conversely, the likelihood of any fluid that flows into a relief groove 21 from outside the flow path member 3 penetrating into other relief grooves 21 is reduced. Reducing this penetration reduces, for example, the likelihood of changes occurring in the characteristics of the flow path member 3.

[0025] The above is an overview of the printer 1 and head 2 according to the embodiment. The printer 1 and head 2 will be described below in general, in the following order: 1. Printer in general (FIGS. 1 and 2) 2. Head 2.1. Head in general (FIG. 3) 2.2. Supply member (FIGS. 3 and 4) 2.3. Flow path member (FIGS. 5 to 8) 2.3.1. Flow path member in general 2.3.2. Examples of flow path shapes 2.3.2.1. Supply port and common flow path 2.3.2.2. Arrangement of individual flow paths 2.3.2.3. Shape of individual flow paths 2.3.3. Relief groove 2.4. Actuator (FIG. 8) 3. Communication holes 3.1. Shape and dimensions of communication holes (FIG. 8) 3.2. Position of communication holes (FIG. 6) 3.3. Example of connection of communication holes 3.3.1. First connection example (FIG. 9) 3.3.2. 3.2.2. Second Connection Example (Fig. 10) 3.3.3. Third Connection Example (Fig. 11) 3.3.4. Fourth Connection Example (Fig. 12) 3.3.5. Fifth Connection Example (Fig. 13) 3.4. Opening or Closing of Communication Holes (Figs. 9 to 11) 3.4.1. First Example of Opening 3.4.2. Second Example of Opening 3.4.3. Example of Closing 3.4.4. Other Examples 4. Specific Examples of Planar Shapes of Relief Grooves Near Communication Holes (Figs. 14 and 15) 5. Summary of Embodiments

[0026] (1. Printer in General) The printer 1 shown in Figures 1 and 2 is configured as a color inkjet printer. The printer 1 moves the printing paper P relative to the head 2 by transporting the printing paper P from a paper feed roller 80A to a collection roller 80B. The paper feed roller 80A and collection roller 80B, as well as various rollers described below, make up a movement unit 85 that moves the printing paper P and the head 2 relative to each other. A control device 88 controls each unit of the printer 1, such as the head 2 and the movement unit 85.

[0027] In this embodiment, the head 2 is fixed to the main body of the printer 1, and the printer 1 is a so-called line printer. Another embodiment of the recording device is a so-called serial printer. In a serial printer, for example, the head 2 is moved back and forth in a direction that intersects with the transport direction of the print paper P, for example, in a direction that is approximately perpendicular. During this reciprocation, the operation of ejecting droplets and the transport of the print paper P are performed alternately.

[0028] Four flat frames 70 are fixed to the printer 1 so as to be approximately parallel to the printing paper P. Five holes (not shown) are formed in each frame 70, and five heads 2 are mounted in each hole. The five heads 2 mounted on one frame 70 make up one head group 72. The printer 1 has four head groups 72, and a total of 20 heads 2 are mounted thereon.

[0029] The heads 2 have an elongated shape extending from the front to the back in FIG. 1, or vertically in FIG. 2. In one head group 72, three heads 2 are lined up in a direction intersecting the transport direction of the print paper P, for example, in a direction approximately perpendicular to it, and the other two heads 2 are lined up at offset positions along the transport direction, with one head between each of the three heads 2. In other words, in one head group 72, the five heads 2 are arranged in a staggered pattern. The heads 2 are arranged so that the printable area of ​​each head 2 is connected in the width direction of the print paper P, i.e., in the direction intersecting the transport direction of the print paper P, or so that the edges overlap, enabling printing without gaps in the width direction of the print paper P.

[0030] The four head groups 72 are arranged along the transport direction of the printing paper P. Each head 2 is supplied with liquid, for example, ink, from a liquid supply tank (not shown). The heads 2 belonging to one head group 72 are supplied with ink of the same color, and the four head groups 72 can print with ink of four colors. The colors of ink ejected from each head group 72 are, for example, magenta (M), yellow (Y), cyan (C), and black (K).

[0031] The number of heads 2 mounted on the printer 1 may be one, as long as printing is performed in a single color within the printable range of one head 2. The number of heads 2 included in a head group 72 and / or the number of head groups 72 can be changed as appropriate depending on the object to be printed and / or the printing conditions. For example, the number of head groups 72 may be increased to print in more colors. Furthermore, by arranging multiple head groups 72 that print in the same color and alternately printing in the transport direction, the transport speed can be increased even when heads 2 with the same performance are used. This allows for a larger printing area per unit time. Furthermore, multiple head groups 72 that print in the same color may be prepared and arranged staggered in a direction intersecting the transport direction to increase the resolution in the width direction of the printing paper P.

[0032] Furthermore, in addition to printing colored ink, a liquid such as a coating agent may be printed uniformly or in a pattern by the head 2 in order to perform surface treatment on the printing paper P. However, instead of printing the coating agent by the head 2, the coating agent may also be uniformly applied by the applicator 76.

[0033] The printing paper P is wound around the paper feed roller 80A, and the printing paper P sent out from the paper feed roller 80A passes under the head 2, then passes between two transport rollers 82C, and is finally collected by the collection roller 80B. When printing, the printing paper P is transported at a constant speed by rotating the transport roller 82C.

[0034] More specifically, printing paper P sent out from paper feed roller 80A passes between two guide rollers 82A and enters head chamber 74. Head chamber 74 houses multiple heads 2 and five guide rollers 82B. Printing paper P is transported over guide rollers 82B. Tension is applied to printing paper P so that the portions between guide rollers 82B (portions facing heads 2) are flat. After leaving head chamber 74, printing paper P passes between two transport rollers 82C, through dryer 78, and between two guide rollers 82D before being collected by collection roller 80B.

[0035] The recording medium may be a roll of cloth in addition to printing paper P. Furthermore, instead of directly transporting printing paper P, the printer 1 may transport a conveyor belt and place the recording medium on the conveyor belt for transport. In this way, sheets of paper, cut pieces of cloth, wood, tiles, etc. can be used as recording media. Furthermore, a liquid containing conductive particles may be ejected from the head 2 to print wiring patterns for electronic devices. Furthermore, a chemical agent may be produced by ejecting a predetermined amount of liquid chemical agent or a liquid containing a chemical agent from the head 2 toward a reaction vessel or the like, causing a reaction.

[0036] For convenience, the following description will basically focus on one head 2. Therefore, for example, hereinafter, when referring to all nozzles 13, unless otherwise specified, this refers to all nozzles 13 in one head 2. When referring to all nozzles 13, unless otherwise specified, a unique nozzle may be treated as a nozzle different from the nozzles 13 specified by the term "all nozzles 13." For example, in order to make the ejection characteristics of the nozzles 13 located at the ends of the head 2 closer to the ejection characteristics of the nozzles 13 located in the center of the head 2, dummy nozzles that do not eject droplets may be provided further outside the nozzles 13 located at the ends. Such dummy nozzles do not need to be included in the "all nozzles 13" reference. The same applies to components other than the nozzles 13.

[0037] (2. Head) (2.1. Head in General) Figure 3 is an exploded perspective view of the head 2. For convenience, Figure 3 and other figures may include an orthogonal coordinate system consisting of the D1 axis, D2 axis, and D3 axis. The D1 axis is, for example, parallel to the direction of relative movement between the head 2 and the recording medium (the transport direction of the print paper P in Figure 1). The relationship between the positive and negative sides of the D1 axis and the direction of travel of the recording medium relative to the head 2 is not particularly important in the description of this embodiment. The D2 axis is, for example, parallel to the ejection surface 3a of the flow path member 3 and orthogonal to the D1 axis. The positive and negative sides of the D2 axis are also not particularly important. The D3 axis is orthogonal to the ejection surface 3a. The -D3 side is the direction from the head 2 to the recording medium.

[0038] The head 2 includes, for example, the flow path member 3 described above, an actuator 5 that applies pressure to the ink in the flow path member 3 to eject ink droplets, a supply member 7 that supplies ink to the flow path member 3, and a flexible substrate 9 that inputs a drive signal to the actuator 5. The actuator 5 overlaps a region R1 indicated by a dotted line on the pressure surface 3b of the flow path member 3. The supply member 7 overlaps (is joined to) the periphery of the region R1 on the pressure surface 3b. The flexible substrate 9 is inserted through a slit 7a in the supply member 7, with one end connected to the top surface of the actuator 5 and the other end extending from above the supply member 7.

[0039] Although not particularly shown, the head 2 may have other components than those described above. For example, the head 2 may have a rigid circuit board connected to the flexible substrate 9 and a housing that covers the upper surface of the supply member 7. Also, unlike the description of the embodiment, instead of regarding the entire configuration shown in Fig. 3 as the head 2, only the flow path member 3 may be regarded as the head, or only the combination of the flow path member 3 and the actuator 5 may be regarded as the head.

[0040] The head 2 may simply be supplied with ink from a tank (not shown), or may be supplied with ink from a tank (not shown) and collect the ink in a tank (not shown). In other words, the ink may or may not be circulated in the head 2. In the latter case, the likelihood of ink solidifying near the nozzles 13, etc. is reduced. In the description of the embodiment, a configuration in which ink is not circulated will basically be taken as an example, and a description of the configuration related to ink circulation will be omitted.

[0041] One head 2 may be configured to eject only one color of ink, or may be configured to eject two or more colors of ink. The latter head 2 may be used to eject one color of ink by supplying ink of the same color to two or more first ports 25 (described below) that are to be supplied with two or more colors of ink. In the description of the embodiment, a configuration capable of ejecting two colors of ink will be mainly taken as an example. However, if there is no particular need to distinguish between the above differences, the description of the configuration related to the two colors will be omitted as appropriate.

[0042] (2.2. Supply Member) Fig. 4 is a perspective view of the supply member 7 as viewed from the bottom side. The supply member 7 shown in Figs. 3 and 4 contributes to supplying ink supplied from a tank (not shown) to the flow path member 3, for example. The supply member 7 may also contribute to mounting the head 2 on the frame 70, or to protecting the actuator 5.

[0043] The supply member 7 has a general shape, for example, of a rectangular flat plate. From another perspective, the shape and dimensions of the supply member 7 in a plan view are generally slightly larger than those of the flow path member 3 in the longitudinal direction. The thickness of the supply member 7 is arbitrary and may be larger than the thickness of the flow path member 3, for example. The supply member 7 has a recess 7b on its lower surface that houses the actuator 5. The periphery of the recess 7b is a joining surface 7c that is joined to the pressure surface 3b of the flow path member 3. The slit 7a described above is located within the recess 7b.

[0044] For example, the entire surface of the bonding surface 7c is basically bonded to the flow path member 3. In other words, the pressure application surface 3b is bonded to the pressure application surface 3b, for example, over the entire periphery surrounding the actuator 5. The bonding is performed, for example, by an adhesive (not shown). The components of this adhesive may be the same as or different from the components of the adhesive 17. In any case, the description below regarding the components of the adhesive 17 may be applied to the adhesive that bonds the bonding surface 7c and the pressure application surface 3b.

[0045] The supply member 7 has one or more (two in the example of FIG. 3 ) first ports 25 through which ink is supplied from a tank (not shown), and one or more (four in the example of FIG. 4 ) second ports 27 through which ink is supplied to the flow path member 3. The first ports 25 and the second ports 27 are connected by a flow path (not shown) inside the supply member 7. The first ports 25 open, for example, on the top surface of the supply member 7. The second ports 27 open at a position opposite a supply port 29 (described later) of the flow path member 3. In the example of FIG. 4 , the second ports 27 open at the joint surface 7 c, and more specifically, at one end or the other end of the supply member 7 in the longitudinal direction.

[0046] If the head 2 only ejects ink of one color, it is sufficient to have only one first port 25 and one second port 27. In the illustrated example, as described above, a configuration capable of ejecting ink of two colors is taken as an example, and therefore two or more first ports 25 and two or more second ports 27 are provided. The two or more first ports 25 are connected to different second ports 27 by different (mutually independent) flow paths within the supply member 7. Specifically, in the illustrated example, one first port 25 is connected to two second ports 27 on the -D1 side. The other second port 27 is connected to two second ports 27 on the +D1 side.

[0047] The material of the supply member 7 is arbitrary. For example, the supply member 7 may be made of metal, resin, ceramic, or a combination of these. Similarly to the flow path member 3, the supply member 7 may be made of a plurality of plate-shaped parts laminated with an adhesive, or may be made integrally as a whole.

[0048] (2.3. Flow Channel Member) (2.3.1. Flow Channel Members in General) As shown in FIG. 3 , the general shape of the flow channel member 3 is, for example, a rectangular flat plate. A rectangle can be said to have a shape with a longitudinal direction and a lateral direction. Various dimensions and dimensional ratios are arbitrary. For example, the length in the longitudinal direction may be two or more times or five or more times the length in the lateral direction. Furthermore, for example, the thickness of the flow channel member 3 may be 0.5 mm or more and 2 mm or less.

[0049] FIG. 5 is an exploded perspective view of the flow path member 3. As shown in FIG.

[0050] As described above, the flow path member 3 is constructed by stacking multiple flow path parts 15 with adhesive 17 ( FIG. 12 ) interposed therebetween. Each flow path part 15 is, for example, approximately plate-shaped. The shape and size of the outer edge of each flow path part 15 are approximately the same as the shape and size of the outer edge of the flow path member 3. In other words, the shape and size of the outer edges of the multiple flow path parts 15 are approximately the same as one another. The number of stacked flow path parts 15 and their thickness are arbitrary. For example, the thickness of the flow path part 15 may be 10 μm or more and 300 μm or less.

[0051] Each flow path part 15 is, for example, integrally formed entirely from one type of material. The materials of the multiple flow path parts 15 may be the same as each other, or may be partially different from each other. The material of the flow path parts 15 is arbitrary and may be, for example, metal, resin, or ceramic. The holes (through holes or recesses) that form the flow paths 11 of the flow path parts 15 may be formed by, for example, dry or wet etching or half etching.

[0052] The type and components of the adhesive 17 are arbitrary. For example, the adhesive 17 may be one that hardens at high temperatures (e.g., a thermosetting resin) or one that hardens at room temperature. The adhesive 17 may be one-component or two-component. The adhesive 17 may be an organic material (e.g., a resin) or an inorganic material.

[0053] The adhesive 17 may be placed on either of the two flow path parts 15 that form one inter-layer space 19, or may be placed on both of them, during the manufacturing process of the flow path member 3. The adhesive 17 may or may not cover the area of ​​the flow path part 15 that forms the upper or lower surface of the flow path 11 (and the relief groove 21 and the communication hole 23).

[0054] In the manufacturing process of the flow path member 3, the adhesive 17 is placed on the flow path part 15 after holes (through holes and recesses) that will become the flow paths 11, the relief grooves 21, the communication holes 23, etc. have been formed. The method of placing the adhesive 17 on the flow path part 15 may be the same as a known method. For example, the adhesive applied to a film may be transferred to the flow path part 15, or screen printing may be used. At this time, appropriate patterning may be performed to avoid the communication holes 23, etc. When the adhesive 17 is placed, for example, the adhesive 17 may be placed with a constant thickness.

[0055] The bonding with the adhesive 17 may be performed by stacking all of the flow path parts 15 at once. In this case, the effects related to the leak test described above are particularly effective. However, bonding may be performed for each part of the flow path parts 15. During bonding, for example, appropriate pressure may be applied between the flow path parts 15. At this time, as can be understood from the fact that various types of adhesive 17 may be used, heating may or may not be performed.

[0056] 8 may have various configurations as long as it is capable of receiving liquid from the outside of the flow path member 3 (the supply member 7 in this embodiment) and has a nozzle 13. The illustrated examples are as follows.

[0057] The flow paths 11 have at least one common flow path 31 and a plurality of individual flow paths 33 (only one is shown in FIG. 8 ) connected to each common flow path 31. Each individual flow path 33 has the nozzle 13 described above, and also has, in order from the common flow path 31 to the nozzle 13, a connection portion 35, a restrictor 37, a supply path 39, a pressure chamber 41, and a descender 43.

[0058] The plurality of individual flow paths 33 and the common flow path 31 are filled with liquid. When the volumes of the plurality of pressure chambers 41 change and pressure is applied to the liquid, the liquid is sent from the plurality of pressure chambers 41 to the plurality of descenders 43, and a plurality of droplets are ejected from the plurality of nozzles 13. In addition, the plurality of pressure chambers 41 are replenished with liquid from the common flow path 31 via the plurality of connection parts 35, throttles 37, and supply paths 39.

[0059] (2.3.2.1. Supply Port and Common Flow Channel) Fig. 6 is a top view of the flow channel member 3. In this figure, the common flow channel 31 is also shown by a dotted line.

[0060] The number of common flow paths 31 is arbitrary, and may be one (corresponding to one color) or multiple. In the example of FIG. 6, eight common flow paths 31 are provided. The multiple common flow paths 31 extend, for example, in parallel with one another in a straight line. The configurations of the multiple common flow paths 31 are basically the same. The relative relationship between the extension direction of the common flow paths 31 and the longitudinal direction of the flow path member 3 may also be set appropriately, and in the example shown, the two are parallel. Note that the common flow paths 31 may be inclined in the longitudinal direction of the flow path member 3 (a direction substantially perpendicular to the transport direction), or may be aligned along the shorter side of the flow path member 3 rather than the longitudinal direction.

[0061] A supply port 29 opens at both ends of each common flow path 31. The supply ports 29 are connected to the second ports 27 of the supply member 7, allowing liquid to be supplied from the supply member 7. The liquid flows into the common flow path 31 from the supply ports 29 at both ends of the common flow path 31 and flows toward the center of the common flow path 31. Note that the supply port 29 may be provided at only one end of each common flow path 31. Furthermore, in a head 2 that circulates ink, a discharge port for discharging liquid from the common flow path 31 to the outside of the flow path member 3 may open in the common flow path 31.

[0062] As described above, the flow path member 3 in the illustrated example is configured to be capable of ejecting ink of two colors. The eight supply ports 29 of the four common flow paths 31 on the +D1 side are connected to one of the two first ports 25 via two second ports 27 (FIG. 4) on the +D1 side of the supply member 7. Similarly, the eight supply ports 29 of the four common flow paths 31 on the -D1 side are connected to the other of the two first ports 25 via two second ports 27 on the -D1 side of the supply member 7. This allows ink of the colors corresponding to each of the two groups of common flow paths 31 to be supplied.

[0063] In the illustrated example, one second port 27 corresponds to multiple (four) supply ports 29, but the relationship between the numbers of the two is arbitrary; for example, the numbers of the two may be the same. When the flow path member 3 is used for a single color, the single color application may be achieved by using a supply member 7 having one second port 27 connected to eight supply ports 29. The four common flow paths 31 may merge at their ends to form a manifold or annular flow path. From another perspective, one or a set of supply ports 29 may be provided for multiple common flow paths 31.

[0064] The shape of the cross section ( FIG. 8 ) of the common flow path 31 and various dimensions of the common flow path 31 may be set as appropriate. In the example of FIG. 8 , the cross section of the common flow path 31 has a rectangular shape. A damper may be provided above and / or below the common flow path 31 to attenuate pressure fluctuations occurring in the common flow path 31.

[0065] (2.3.2.2. Arrangement of individual flow paths) Fig. 7 is an enlarged view (planar perspective view) of region VII in Fig. 6. In Fig. 7, in addition to the flow paths shown in Fig. 6, pressure chambers 41 and descenders 43 are also shown. For convenience, Fig. 7 also shows flow paths that are hidden by flow path parts 15 and cannot be seen by solid lines.

[0066] The individual flow paths 33 are arranged along each common flow path 31 (in the length direction of the common flow path 31). That is, the nozzles 13 (FIG. 8) are arranged along the common flow path 31. The configurations of one common flow path 31 and the individual flow paths 33 connected to the one common flow path 31 are basically the same for the multiple common flow paths 31. In the following, the description may focus on only one common flow path 31.

[0067] The multiple pressure chambers 41 connected to one common flow path 31 are arranged in two rows on each side of the common flow path 31, for a total of four rows on both sides. The same applies to the descenders 43 and the nozzles 13. The four types of individual flow paths 33 connected to the four rows of pressure chambers 41 differ from each other, for example, in the orientation and / or length of the throttles 37 in a plan view. This achieves the arrangement of the pressure chambers 41 as described above. Note that the number of rows of pressure chambers 41 connected to one common flow path 31 may be other than four (for example, one or two).

[0068] The multiple nozzles 13 are arranged so that they do not overlap one another when viewed in the direction of relative movement (direction D1) between the head 2 and the printing paper P. This allows for the formation of dots arranged in a direction perpendicular to the transport direction at a pitch narrower than the pitch of the nozzles 13 in each row when droplets are ejected toward the printing paper P while the printing paper P is transported.

[0069] 8, the pressure chamber 41 is open to the pressure surface 3b, for example, and is blocked by the actuator 5. The pressure chamber 41 may be blocked by a relatively thin flow path part 15. The upper surface of the flow path part 15 may form the pressure surface 3b, and the actuator 5 may be disposed on the pressure surface 3b.

[0070] The pressure chamber 41 is formed, for example, in a thin shape that spreads with a constant thickness along the pressure surface 3b. The thin shape is, for example, a shape whose thickness is smaller than any diameter in a plan view. However, the pressure chamber 41 may have a portion whose thickness varies. The planar shape of the pressure chamber 41 may be any appropriate shape, such as a rhombus (example of FIG. 7 ), a circle, or an ellipse.

[0071] The descender 43 extends from the pressure chamber 41 toward the ejection surface 3a. The shape of the descender 43 is, for example, generally cylindrical (a right circular cylinder or an oblique circular cylinder). In a plan view, the descender 43 is connected to, for example, an end of the pressure chamber 41 in the longitudinal direction (one acute corner of the diamond in the example of FIG. 7). The arrangement in which the multiple nozzles 13 do not overlap each other when viewed in the D1 direction described above may be achieved by making the positions of the pressure chambers 41 and the descenders 43 different from each other among the multiple individual flow paths 33, or by making the shapes of the descenders 43 different from each other.

[0072] The nozzle 13 opens to a part of the bottom surface of the descender 43 (the surface opposite to the pressure chamber 41). The nozzle 13 is located, for example, approximately in the center of the bottom surface of the descender 43. However, the nozzle 13 may be provided eccentrically with respect to the center of the bottom surface of the descender 43. The vertical cross section of the nozzle 13 is tapered so that the diameter decreases toward the ejection surface 3a. However, the nozzle 13 may be partially or entirely reverse tapered.

[0073] The connection portion 35 extends upward, for example, from the upper surface of the common flow path 31. The restrictor 37 extends from this portion in a direction along the upper and lower surfaces of the flow path part 15. The supply path 39 extends upward from the restrictor 37 and is connected to the lower surface of the pressure chamber 41. In a plan view (viewed in the D3 direction), the connection position of the supply path 39 to the pressure chamber 41 is, for example, the end of the lower surface of the pressure chamber 41 on the opposite side from the descender 43 with respect to the center of the lower surface.

[0074] The orifice 37 has a smaller cross-sectional area than the connection portion 35 and the supply path 39. Furthermore, the orifice 37 has the smallest cross-sectional area, for example, in the portion (35, 37, 39, 41, and 43) of the individual flow path 33 excluding the nozzle 13. The relationship in size between the cross-sectional area of ​​the nozzle 13 and the cross-sectional area of ​​the orifice 37 is arbitrary. The cross-section is a cross section that intersects with the flow direction (the same applies to the communication hole 23, etc., described later). The cross-section of the orifice 37 illustrated in FIG. 8 is perpendicular to the left-right direction of the figure. If the cross-sectional area is not constant in the flow direction, the above explanation of the comparison of areas may be applied to, for example, a comparison of the minimum area of ​​each portion in the flow direction.

[0075] Similarly, the restrictor 37 has a smaller diameter than, for example, the connection portion 35 and the supply path 39. Furthermore, the restrictor 37 has the smallest diameter, for example, in the portion (35, 37, 39, 41, and 43) of the individual flow path 33 excluding the nozzle 13. The relationship in size between the diameter of the nozzle 13 and the diameter of the restrictor 37 is arbitrary. Note that the diameter is the length of a line segment that passes through the geometric center of the cross section of each flow path and has both ends on the inner surface of the flow path (the same applies to the communicating hole 23, etc., described later). If the cross section is not circular, the above description of the diameter comparison may be applied to, for example, a comparison of the minimum diameter in the cross section. If the diameter is not constant in the flow direction, the above description of the diameter comparison may be applied to, for example, the minimum diameter in the flow direction of each portion.

[0076] (2.3.3. Relief Groove) As shown in Fig. 8 , the relief groove 21 is configured as a recess formed on the surfaces of the flow path parts 15 that are joined together (main surfaces, from another perspective). However, part of the relief groove 21 may be configured as a slit formed on the main surface of the flow path part 15. All interlayer parts 19 have the relief groove 21 (example of Fig. 8 ). However, there may be interlayer parts 19 that do not have the relief groove 21. In the description of the embodiment, an example will be taken in which the relief groove 21 is a recess and the relief groove 21 is provided in all interlayer parts 19.

[0077] In each inter-layer space 19, the relief groove 21 may be formed on the lower surface of the upper (+D3 side) flow path part 15 (example in FIG. 8 ), or on the upper surface of the lower flow path part 15, or may be formed on both the upper and lower flow path parts 15. In addition, whether the relief groove 21 is formed in the upper and / or lower flow path part 15 may be consistent across multiple inter-layer spaces 19 (example in FIG. 8 ), or may not be consistent.

[0078] Although not particularly shown, a relief groove 21 may be formed on the upper surface of a flow path part 15 that overlaps below a predetermined flow path part 15, and a relief groove 21 may be formed on the lower surface of a flow path part 15 that overlaps above the predetermined flow path part 15, so that a flow path part 15 that does not have a relief groove 21 may exist between adjacent inter-layer spaces 19 that have a relief groove 21. Conversely, a flow path part 15 that has a relief groove 21 on both the upper surface and the lower surface may exist.

[0079] When the predetermined interlayer 19 has the relief groove 21 on only one of the upper surface and the lower surface, and the adhesive 17 is disposed on only one of the upper surface and the lower surface of the predetermined interlayer 19 during the manufacturing process, the adhesive 17 may be disposed on either the surface having the relief groove 21 or the surface not having the relief groove 21. In either case, the adhesive 17 may be disposed in a region overlapping the relief groove 21 (example of FIG. 12 ), or may not be disposed by patterning the adhesive 17.

[0080] The cross-sectional shape of the relief groove 21 may be appropriately set, for example, semicircular or rectangular with chamfered corners. The depth (depth of the deepest portion in the cross section of the relief groove 21), width (width of the widest portion in the cross section of the relief groove 21), and / or cross-sectional area of ​​the relief groove 21 may be different from each other in at least some of the interlayer spaces 19 (or, from another perspective, the multiple flow path parts 15) (example in FIG. 8 ), or may be the same from each other in all of the interlayer spaces 19. An example of the former embodiment is one in which the depth, width, and / or cross-sectional area of ​​the relief groove 21 increases in a relatively thicker flow path part 15 (example shown in the figure). The depth of the relief groove 21 may be, for example, between one-third and two-thirds of the thickness of the flow path part 15 in which the relief groove 21 is formed.

[0081] Each interlayer 19 may have only one relief groove 21, or may have two or more relief grooves 21 that are isolated from one another. In the description of the embodiment, a plurality of recesses that are connected to one another in one interlayer 19 (including a case where the recesses are connected to one another via through holes that serve as communicating holes 23) is regarded as a single relief groove 21. Relief grooves 21 located in different interlayers 19 are not regarded as a single relief groove 21 even if they are connected to one another via a common communicating hole 23. For example, all of the plurality of relief grooves 21 in a given interlayer 19 may be connected to different communicating holes 23, or some of them (e.g., those with a relatively small volume) may not be connected to a communicating hole 23.

[0082] The multiple relief grooves 21 are, for example, basically isolated from the flow paths 11. For example, all of the relief grooves 21 connected to the communication holes 23 are isolated from the flow paths 11. This reduces, for example, the likelihood that excess adhesive 17 will flow into the flow paths 11 via the relief grooves 21, and also reduces the need to block the flow paths 11 during leak testing. However, some or all of the relief grooves 21 may be connected to the flow paths 11.

[0083] The planar shape of the relief groove 21 may be any appropriate shape. Fig. 8 illustrates an example in which the relief groove 21 is provided so as to surround each portion of the flow path 11 in each inter-layer space 19. For example, the two recesses drawn on both sides of the descender 43 in each inter-layer space 19 represent relief grooves 21 extending in an annular shape so as to surround the descender 43. The same applies to the two recesses on both sides of the other portions (35, 37, 39, and 41) of the individual flow paths 33 and the two recesses on both sides of the common flow path 31.

[0084] (2.4. Actuator) As shown in Fig. 3, the actuator 5 is, for example, generally plate-shaped and has an area that covers the plurality of pressure chambers 41. The actuator 5 shown in Fig. 8 is configured as a so-called unimorph type piezoelectric actuator. The actuator 5 may also be configured as another type of piezoelectric actuator, such as a bimorph type. The actuator 5 has, for example, a vibration plate 47, a common electrode 49, a piezoelectric layer 51, and individual electrodes 53, in this order from the flow path member 3 side.

[0085] The vibration plate 47, common electrode 49, and piezoelectric layer 51 extend across the multiple pressure chambers 41 in a plan view. That is, they are provided in common to the multiple pressure chambers 41. The individual electrodes 53 are provided for each pressure chamber 41 in a position facing the pressure chamber 41. The number of individual electrodes 53 is basically the same as the number of pressure chambers 41. Note that the portions of the actuator 5 corresponding to each pressure chamber 41 are referred to as pressure elements 45.

[0086] The portion of the piezoelectric layer 51 sandwiched between the individual electrode 53 and the common electrode 49 is polarized in the thickness direction. Therefore, for example, when an electric field (voltage) is applied in the polarization direction of the piezoelectric layer 51 by the individual electrode 53 and the common electrode 49, the piezoelectric layer 51 contracts in a direction along the layer. This contraction is regulated by the vibration plate 47. As a result, the pressure element 45 is flexed and deformed so as to be convex toward the pressure chamber 41. Consequently, the volume of the pressure chamber 41 is reduced, and pressure is applied to the liquid in the pressure chamber 41. When an electric field (voltage) is applied in the opposite direction to the above by the individual electrode 53 and the common electrode 49, the pressure element 45 is flexed and deformed in the direction opposite to the pressure chamber 41.

[0087] The individual electrodes 53 have electrode bodies 53a that overlap the pressure chambers 41 in a plan view, and lead electrodes 53b that extend from the electrode bodies 53a. The lead electrodes 53b are connected to the flexible substrate 9 via a conductive bonding material (not shown). In addition, although not specifically shown, the common electrode 49 is connected to the flexible substrate 9 via a through conductor (not shown) that penetrates the piezoelectric layer 51 and a conductive bonding material.

[0088] 8 and 9, each communication hole 23 penetrates one or more flow path parts 15 located from the interlayer 19 to which the relief groove 21 it is connected belongs to to the pressure surface 3b. The communication holes 23 penetrating the plurality of flow path parts 15 are formed, for example, by all of the holes 15h (reference numerals shown in FIG. 8) penetrating the plurality of flow path parts 15 in the thickness direction (direction D3) overlapping each other. More specifically, in the illustrated example, the plurality of holes 15h have roughly the same shape and dimensions (diameter, etc.) as one another in a plan view (seen in the direction D3), and their centers (e.g., geometric centers) coincide with one another. As a result, the communication holes 23 are formed in a roughly straight columnar shape.

[0089] However, the multiple holes 15h constituting one communication hole 23 may have different shapes and dimensions (diameter, etc.). Furthermore, some or all of the multiple holes 15h may be offset from one another. As a result, for example, the communication hole 23 may be formed in an oblique column shape. Furthermore, non-adjacent holes 15h (e.g., the uppermost hole 15h and the lowermost hole 15h) may not overlap with each other. Furthermore, by forming some of the holes 15h in a slit shape, the communication hole 23 may have a portion that can be considered to extend along the D1D2 plane. Part of the slit may also be a recessed groove.

[0090] The shape of the hole 15h is arbitrary. For example, the planar shape of the hole 15h may be circular, elliptical, or rectangular. For convenience, in the description of the embodiment, unless otherwise specified, the diameter and / or cross-sectional area of ​​the communication hole 23 may be described assuming that the planar shape of the hole 15h is circular. The inner wall of the hole 15h may be parallel to the D3 direction, or may be partially or entirely inclined in the D3 direction. From another perspective, the diameter of the hole 15h may be constant in the D3 direction, or may increase or decrease toward the +D3 side, the −D3 side, or the center in the penetration direction.

[0091] The diameter and cross-sectional area of ​​the communication hole 23 are arbitrary. For example, in the example of FIG. 8 , the minimum diameter of the communication hole 23 is larger than the minimum width of the relief groove 21 connected to the communication hole 23. Note that, similar to the individual flow paths 33, the minimum diameter may be the smallest diameter in each cross section and the smallest diameter in various cross sections in the flow direction. Furthermore, as described above, the width of the relief groove 21 may be the largest width in each cross section (the width at the bottom surface of the flow path part 15 in the example of FIG. 8 ). The minimum width may be the smallest width (the largest width in each cross section) in various cross sections in the extension direction of the relief groove 21 (the flow direction of the adhesive 17). Similarly, the maximum diameter (maximum width) may be the largest diameter (width) in each cross section and various cross sections in the flow direction. The same applies below.

[0092] 8 , the minimum diameter of the communication hole 23 is larger than the minimum diameter of the portions (35, 37, 39, 41, and 43) of the individual flow paths 33 other than the nozzles 13. As described above, in the example of FIG. 8 , it is the restrictor 37 that has the minimum diameter of the above-mentioned portions. Also, in the example of FIG. 8 , the minimum diameter of the communication hole 23 is larger than the minimum diameter of the descender 43. The minimum diameter of the communication hole 23 may be larger than the maximum diameter of the descender 43, or may be larger than the maximum diameter of the portions of the individual flow paths 33 other than the pressure chambers 41, or may be larger than the maximum diameter of the individual flow paths 33.

[0093] It has been mentioned above that the shapes and dimensions of the multiple individual flow paths 33 may be slightly different from one another. In such cases, the explanation of the comparison between the dimensions of a specific communication hole 23 and the minimum area and minimum diameter of the cross section of an individual flow path 33 may apply to the smallest minimum area and minimum diameter among the multiple individual flow paths 33. Conversely, the explanation of the comparison between the maximum area and maximum diameter may apply to the largest maximum area and maximum diameter among the multiple individual flow paths 33. However, normally, the differences in the shapes and dimensions of the cross sections of the multiple individual flow paths 33 are relatively small, and it is not necessary to take these differences into consideration.

[0094] Although the above description has been made with respect to the lower limit of the minimum diameter of the communicating holes 23 in comparison with the diameters of the other components, the upper limit of the minimum diameter or the lower or upper limit of the maximum diameter of the communicating holes 23 may also be set appropriately. However, if the communicating holes 23 are too large, the rigidity of the flow path member 3 decreases. The minimum diameter and / or the maximum diameter of the communicating holes 23 may be set smaller than the maximum diameter of the common flow path 31, smaller than the minimum diameter of the common flow path 31, or smaller than the maximum diameter of the individual flow paths 33, for example.

[0095] The above description of the comparison of diameters may be applied to the comparison of cross-sectional areas by replacing the "minimum diameter" and "minimum width" with the "minimum area" and the "maximum diameter" with the "maximum area." Note that the minimum area or maximum area may be the minimum or maximum in various cross sections in the flow direction, similar to the individual flow paths 33.

[0096] Some or all of the multiple communication holes 23 may have the same or different cross-sectional shapes, cross-sectional areas (minimum area and / or maximum area), and / or diameters (minimum diameter and / or maximum diameter). In the latter case, the relationship between the sizes of the multiple communication holes 23 and the sizes of the multiple relief grooves 21 connecting the multiple communication holes 23 may be arbitrary, and the relationship between the sizes of the multiple communication holes 23 and the thickness of the flow path part 15 in which the multiple relief grooves 21 connecting the multiple communication holes 23 are provided may also be arbitrary.

[0097] 10 to 12, which will be described later, illustrate an embodiment in which the cross-sectional shapes and dimensions (minimum area, maximum area, minimum diameter and / or maximum diameter; the same applies below) of the multiple communication holes 23 are the same as each other. In the examples of FIGS. 10 to 12, the cross-sectional shapes and dimensions of the multiple relief grooves 21 are also the same as each other. In the examples of FIGS. 10 to 12, the thickness of at least some of the flow path parts 15 (flow path part 15M in the illustrated example) is different from the thickness of at least some of the other flow path parts 15.

[0098] 9 illustrates an example in which the cross-sectional dimensions of some of the communication holes 23 (communication holes 23M) are different from the cross-sectional dimensions of other communication holes 23. Specifically, the cross-sectional dimension of the relief groove 21 of a relatively thick flow path part 15 (flow path part 15M in the illustrated example) is made relatively large, and the cross-sectional dimension of the communication hole 23 (communication hole 23M in the illustrated example) connected to the relief groove 21 with the relatively large cross-sectional dimension is made relatively large.

[0099] (3.2. Position of communicating holes) The communicating holes 23 may be positioned at any position within the flow path member 3 in a plan view. In the example of FIG. 6 , the multiple communicating holes 23 (at least their upper ends) are located at both ends of the flow path member 3 in the longitudinal direction (direction D2). In this case, the longitudinal (or lateral) ends may be defined more specifically as portions that are further outward in the longitudinal (or lateral) direction than the flow paths 11 and / or the actuators 5. Typically, the flow paths and the actuators 5 occupy a relatively large area toward the center of the flow path member 3, and therefore the areas outside of these are the ends of the flow path member 3. And / or the ends in a predetermined direction may be defined, for example, as both side portions when the flow path member 3 is divided into five equal parts in a predetermined direction.

[0100] Unlike the example in Fig. 6 , the multiple communication holes 23 may be located only at one end in the longitudinal direction, or may be located at an end in the lateral direction in addition to or instead of the end in the longitudinal direction. Furthermore, some or all of the multiple communication holes 23 may not be arranged collectively in a specific region of the flow path member 3 (the end in the longitudinal direction in the example in Fig. 6 ), but may be dispersed at various positions in the flow path member 3. Some or all of the multiple communication holes 23 may be located in the arrangement region of the actuator 5 or in the arrangement region of the flow path 11. In this case, the communication holes 23 may be blocked by the actuator 5, or may not be blocked by the actuator 5 by appropriately forming holes in the actuator 5.

[0101] When a plurality of communication holes 23 are arranged together in a specific region (for example, one end in the longitudinal direction) of the flow path member 3, the arrangement (arrangement) of the plurality of communication holes 23 in the specific region is also arbitrary. In the example of Fig. 6, the plurality of communication holes 23 are arranged in a staggered pattern in two rows along the short side of the flow path member 3, except for the central side in the D1 direction. In other words, with respect to the positions in the arrangement direction (D1 direction) of the plurality of communication holes 23, the communication holes 23 in one row are located between the communication holes 23 in the adjacent row (the communication holes 23 in two adjacent rows are located alternately one by one).

[0102] More specifically, in the example of FIG. 6 , the pitch of the communication holes 23 in each row (the distance between the centers of adjacent communication holes 23) is constant. Furthermore, the pitch of the communication holes 23 is the same between two rows. The two rows are offset from each other by ½ the pitch in the D1 direction. Either the pitch or the distance between the center lines of the two rows may be larger. In the example of FIG. 6 , the difference between the two is ½ the pitch or less. That is, the multiple communication holes 23 are dispersed relatively evenly in both the D1 direction and the D2 direction.

[0103] Unlike the illustrated example, the two rows of communication holes 23 may be aligned along the short side direction (at the same position in the short side direction). Furthermore, regardless of whether they are staggered or not, the multiple communication holes 23 may be aligned in three or more rows, and the pitch may not be constant. An arrangement that cannot be considered as being aligned in a specific direction may also be employed.

[0104] The distance between the communicating holes 23 is also arbitrary. For example, the center-to-center distance between the communicating holes 23 (at least the upper ends thereof) that are closest to each other may be at least half or equal to the minimum or maximum diameter of the supply port 29. As is clear from the fact that the multiple communicating holes 23 do not need to be arranged together in a specific region, there is no particular upper limit to the distance between the communicating holes 23.

[0105] (3.3. Examples of Connection of Communication Holes) As described in the overview of the embodiments, when one relief groove 21 (first relief groove) located in one interlayer space 19 and one relief groove 21 (second relief groove) located in another interlayer space 19 are considered, these two relief grooves 21 are connected to different communication holes 23 and are isolated from each other. Conversely, as long as the above requirements are met, it is optional to determine to which communication hole 23 the relief groove 21 of another interlayer space 19 is connected. In other words, the above requirements for the first relief groove and the second relief groove may be met in various connection modes. Some examples are shown below.

[0106] In the examples described below, only the differences from the examples described above will be described. Items not specifically mentioned may be the same as the examples described above. The same applies to examples related to opening or closing the communication hole 23 described below.

[0107] 9 , as described in the overview of the embodiment, the relief grooves 21 of all interlayer spaces 19 are connected to different communication holes 23 and isolated from one another. Note that, taking into consideration the presence of relief grooves 21 that are not connected to communication holes 23 and are isolated from the outside (see the first annular portion 21a in FIG. 14 described later), strictly speaking, all relief grooves 21 connected to at least one of the multiple communication holes 23 are isolated from the relief grooves of all interlayer spaces 19 other than the one they are connected to.

[0108] In the example of Fig. 9 , when focusing on any one of the relief grooves 21 (first relief groove) in any one of the interlayer spaces 19 (first interlayer spaces), it can be said that the first relief groove is isolated from the relief grooves 21 in all interlayer spaces 19 other than the first interlayer space. In other words, a higher-level concept than the concept described in the previous paragraph can be extracted from the example of Fig. 9 . In this higher-level concept, unlike the example of Fig. 9 , the relief grooves 21 other than the first relief groove may be connected to a common communication hole 23 with the relief grooves 21 in interlayer spaces 19 other than the one to which they belong (see Figs. 10 and 11 ).

[0109] (3.3.2. Second Connection Example) FIG. 10 is a cross-sectional view similar to FIG. 9. In this example, the relief grooves 21 of the interlayers 19N to 19P are connected to a common communication hole 23N. The interlayers 19N to 19P have the same planar shape (the shape of the hole constituting the flow path 11 when viewed in the D3 direction) of at least one of the flow paths 11 of the two flow path parts 15 constituting each interlayer 19. In other words, the flow path parts 15N to 15P have the same planar shape of the flow path 11. Such interlayers 19 (flow path parts 15) are usually adjacent to each other.

[0110] The number of interlayers 19 connected to the common communication hole 23 as described above is not limited to three, but may be two, four, or more. Furthermore, among multiple interlayers 19 having the same planar shape related to the flow path 11 of at least one flow path part 15, only some may be connected to the common communication hole 23. Flow path parts 15 having the same planar shape related to the flow path 11 may have the same thickness, thereby having the same three-dimensional shape related to the flow path 11. Flow path parts 15 of multiple interlayers 19 connected to the common communication hole 23 may have the same planar shape related to the flow path 11, as well as the same planar shape (and three-dimensional shape) of the relief grooves 21 and the communication holes 23. It is clear that errors and the like may be ignored in determining whether the planar shapes are the same. For example, when the inner walls of the holes constituting the flow path 11 are not parallel to the D3 direction, the identity of the planar shapes may be determined by focusing on the shape on the −D3 side or the +D3 side.

[0111] From the example of Figure 10, a concept can be extracted that focuses on inter-layer spaces 19 other than inter-layer spaces 19N-19P. Inter-layer spaces 19 (19L-19N and 19Q) formed by two flow path parts 15 having different planar shapes related to the flow path 11 will be referred to as third inter-layer spaces. Inter-layer spaces 19 (19O and 19P) formed by two flow path parts 15 having the same planar shape related to the flow path 11 will be referred to as fourth inter-layer spaces. In this case, all of the relief grooves 21 connected to any of the multiple communication holes 23 in all of the third inter-layer spaces are connected to different communication holes 23 (23L-23N and 23Q) and are isolated from each other. In addition, all of the escape grooves 21 connected to any of the multiple communication holes 23 between all of the third layers are also isolated from all of the escape grooves 21 between all of the fourth layers (interlayers 19O and 19P for interlayers 19L and 19M as the third layers) formed by two flow path parts 15 whose planar shape related to the flow path 11 is different from that of either of the two flow path parts that form their own interlayer 19.

[0112] As described in the previous paragraph, the relief groove 21 between the third interlayers may be isolated from the relief groove 21 between the fourth interlayers (e.g., the interlayers 19O and 19P for the interlayer 19N as the third interlayer) formed by two flow path parts 15 whose planar shape related to the flow path 11 is the same as that of either of the two flow path parts 15 that form the interlayer 19 itself (e.g., the example in FIG. 9 and the example in FIG. 11 described later), or may not be isolated (e.g., the interlayer 19N in the example in FIG. 10). Furthermore, as described in the previous paragraph, the fourth interlayer may not exist. In the example in FIG. 10, the relief groove 21 between at least one third interlayer (interlayer 19N) is connected to a common communication hole 23 (23N) with the relief groove 21 between at least one fourth interlayer (interlayer 19O and / or 19P) formed by flow path parts 15 whose planar shape related to the flow path 11 is the same as that of either of the two flow path parts 15 that form the interlayer 19 itself. As already mentioned, each interlayer space 19 may have a plurality of relief grooves 21, and in this case, the separation may be achieved as described in the previous paragraph.

[0113] (3.3.3. Third Connection Example) Fig. 11 is a cross-sectional view similar to Fig. 9. In the example of Fig. 10 described above, if the planar shapes of the flow paths 11 of the flow path parts 15 are the same, the relief groove 21 between the third layer (19N) and the relief groove between the fourth layers (19P and 19O) may be connected to the same communication hole 23 (23N). In the example of Fig. 11, the above connection is not made. That is, only the fourth layers (19P and 19O) that have the same planar shapes of the flow paths 11 are connected to a common communication hole (communication hole 23O).

[0114] (3.3.4. Fourth Connection Example) Fig. 12 is a cross-sectional view similar to Fig. 9. However, Fig. 12 shows a cross section of the entire flow path member 3 in the longitudinal direction, and the supply member 7 and the flow path 11 are omitted from the illustration.

[0115] In this example, one relief groove 21 is connected to two communication holes 23. In this way, one relief groove 21 may be connected to two or more communication holes 23. However, even in this case, the relief groove 21 in one interlayer space 19 and the relief groove 21 in another interlayer space 19 are connected to different communication holes 23 and are isolated from each other.

[0116] When one relief groove 21 is connected to two or more communication holes 23, the two or more communication holes 23 may be positioned arbitrarily in a plan view within the flow path member 3. In the illustrated example, the two communication holes 23 (at least their upper ends) are located at one end and the other end of the flow path member 3 in the longitudinal direction.

[0117] The fourth connection example may be combined with any of the first to third connection examples.

[0118] (3.3.5. Fifth Connection Example) Fig. 13 is a top view of one of the flow path parts 15 of the flow path member 3. Here, the flow path part 15 (for example, any of the flow path parts 15C to 15E in the example of Fig. 8) that constitutes the common flow path 31 is taken as an example. In addition, the relief grooves 21 (21A and 21B) provided on the lower surface of the flow path part 15 are indicated by dotted lines.

[0119] As described above, each interlayer space 19 may have two or more escape grooves 21 (21A and 21B) that are isolated from each other. The two or more escape grooves 21 may be connected to different communication holes 23. The two or more escape grooves 21 (21A and 21B) may correspond to divided flow paths 12 (12A and 12B) through which inks of different colors (liquids of different types) flow in a head 2 capable of ejecting inks of two or more colors.

[0120] As described above, in the illustrated example, the four common flow paths 31 on the +D1 side and the four common flow paths 31 on the −D1 side are isolated from each other and can accommodate inks of different colors. Each divided flow path 12 includes, for example, at least one common flow path 31 (four in the illustrated example) and a plurality of individual flow paths 33 connected to each common flow path 31.

[0121] Whether two or more relief grooves 21 correspond to two or more divided flow paths 12 may be determined appropriately based on the positional relationship between the relief grooves 21 and the divided flow paths 12, etc. For example, if one relief groove 21 surrounds one divided flow path 12 (or may even form a closed area) in one inter-layer space 19 and does not surround other divided flow paths 12, the one relief groove 21 corresponds to the one divided flow path 12. Furthermore, if the shortest distance between one relief groove 21 and one divided flow path 12 is shorter than the shortest distance between the one relief groove 21 and the other divided flow paths 12, the one relief groove 21 may be determined to correspond to the one divided flow path 12.

[0122] 13 , each of the relief grooves 21A and 21B surrounds four common flow paths 31 corresponding to each color. This identifies the relief grooves 21A and 21B as corresponding to the divided flow paths 12A and 12B, respectively. Note that the relief groove 21 corresponding to the divided flow path 12A or 12B may have a portion that surrounds each common flow path 31 individually, or a portion that surrounds multiple individual flow paths 33 individually or collectively, in addition to or instead of the shape shown in the figure.

[0123] The position of the communication hole 23 connecting two or more relief grooves 21 corresponding to two or more divided flow paths 12 within the flow path member 3 in a plan view is arbitrary. In the example of FIG. 13 , the communication hole 23 connecting to relief groove 21A is located at one end in the longitudinal direction. The communication hole 23 connecting to relief groove 21B is located at the other end in the longitudinal direction. Furthermore, the two are arranged at positions that are rotationally symmetrical by 180°. Unlike the example shown in the figure, the two do not have to be positioned in rotationally symmetrical positions, and may be located at ends on the same side in the longitudinal direction.

[0124] As described above, the head 2 can be used for two colors of ink, but may also be used for only one color of ink. If it is unclear which color the head 2 will be used for, the escape grooves 21A and 21B can be said to be escape grooves 21 corresponding to the divided flow paths 12A and 12B, which are isolated from each other.

[0125] In the illustrated example of the flow path member 3, not only are two divided flow paths 12 isolated from each other, but the four common flow paths 31 are also isolated within each divided flow path 12. Therefore, each divided flow path 12 has four groups of flow paths that are isolated from each other (each group has one common flow path 31 and multiple individual flow paths 33 connected to the one common flow path 31). Multiple escape grooves 21 may be provided in multiple groups of flow paths corresponding to one color and may be connected to different communication holes 23. Note that in a state where only the flow path member 3 is present (e.g., a state where the supply member 7 is not combined), it may or may not be possible to distinguish whether the mutually isolated flow paths are divided flow paths 12 based on the positional relationship of the multiple nozzles 13, etc.

[0126] The fifth connection example may be combined with any of the first to third connection examples, and / or may be combined with the fourth connection example.

[0127] (3.4. Opening or Closing of Communication Hole) As can be understood from the description of the outline of the invention, the communication hole 23 may be open to the outside at least during the process of bonding the plurality of flow path parts 15. The external state (for example, the magnitude of the air pressure and the type of gas) is arbitrary, and may be, for example, a state in which air is present under atmospheric pressure. Furthermore, when a leak test is performed, a part of an instrument or device for measuring the amount of exhaust from the communication hole 23 may be placed over the communication hole 23. The communication hole 23 may be open to, for example, the internal space of the instrument or device (which may also be considered to be the outside of the flow path member 3), or may be open to the outside via the instrument or device.

[0128] As the manufacturing process of the head 2 progresses and other components (e.g., the actuator 5 and the supply member 7) are combined with the flow path member 3, and / or when the head 2 reaches a state where it can be circulated, the communication hole 23 may be open to the outside or may be blocked. When the communication hole 23 is blocked, the communication hole 23 may be, for example, airtightly (and / or liquidtightly) sealed, or may not be sealed at all. Note that in the description of the embodiments, when it is stated that the communication hole 23 is blocked, it is understood that the communication hole 23 may be sealed unless a contradiction arises. Whether open or blocked, the specific form may be various. Examples are shown below.

[0129] (3.4.1. First Example of Opening) In the example shown in FIG. 9 , when the supply member 7 is joined to the flow path member 3, the communication hole 23 is open to the outside via at least one hole 55 (multiple in the example of FIG. 9 ) of the supply member 7. As the manufacturing process of the head 2 progresses further, the hole 55 may be blocked or may remain open. In the former case, for example, the outlet (the portion opposite the communication hole 23) of the hole 55 may be filled with adhesive, or a predetermined member may be joined to the surface where the outlet opens (top surface 7d in the illustrated example).

[0130] The number, shape, size, etc. of the at least one hole 55 are arbitrary. In the example of Fig. 9, a plurality of holes 55 are provided individually (one-to-one) for a plurality of communication holes 23. Note that the hole 55 in this form may be referred to as hole 55A.

[0131] The hole 55 has an opening on the joining surface 7c of the supply member 7 that is joined to the flow path member 3. The opening of this hole 55 faces the opening of the communication hole 23 that opens on the pressurizing surface 3b. The former opening and the latter opening face each other via the hole 55A. For example, the hole 55 extends from the joining surface 7c to the upper surface 7d on the opposite side and opens on the upper surface 7d. In the example of FIG. 9 , the shape of the hole 55 (55A) is a right column (e.g., a right circular cylinder). Of course, the shape of the hole 55 (55A) may be other than that shown in the figure. For example, the description of the shape of the communication hole 23 may be applied to the shape of the hole 55 (55A). The multiple holes 55A are independent (isolated) from one another.

[0132] The minimum diameter, maximum diameter, minimum cross-sectional area, and / or maximum cross-sectional area of ​​the holes 55A may be smaller, equal to, or larger than the communicating holes 23 connected to the holes 55A. The openings of the opposing holes 55A on the joining surface 7c and the openings of the communicating holes 23 on the pressure surface 3b may have the same shape and dimensions, or may have different shapes and / or dimensions.

[0133] 10, the hole 55 has a configuration in which the multiple holes 55A in FIG. 9 are aggregated into one on the outlet side (top surface 7d side). Note that a hole 55 of this configuration may be referred to as hole 55B. In other words, the hole 55B has multiple branch portions 55a and a confluence portion 55b formed by the convergence of the multiple branch portions 55a. Like the multiple holes 55A, the multiple branch portions 55a have multiple openings on the joining surface 7c, and these multiple openings face the openings of the multiple communication holes 23 on the pressurizing surface 3b in a one-to-one relationship. The confluence portion 55b opens on the top surface 7d. Note that one hole 55B may correspond to all or some of the communication holes 23 located in a specific region (e.g., one end portion of the flow path member 3 in the longitudinal direction). With regard to the latter, for example, there may be two or more holes 55B for one particular area.

[0134] The shape and dimensions of each hole 55B are arbitrary. For example, in the example of FIG. 10 , two branched portions 55a join together, and two other branched portions 55a join together to form two intermediate portions (reference numerals omitted), and then the two intermediate portions join together to form the joining portion 55b. Unlike the illustrated example, such a step-by-step joining is not required. Furthermore, the number of stages when joining is performed step by step, and the number of branched portions 55a joining at each stage, are also arbitrary.

[0135] Furthermore, for example, the minimum diameter, maximum diameter, minimum cross-sectional area, and / or maximum cross-sectional area of ​​the confluence portion 55b may be smaller, equal to, or larger than those of each of the branch portions 55a (example of FIG. 10 ). Furthermore, for one hole 55B, the minimum cross-sectional area (and / or maximum cross-sectional area) of the confluence portion 55b may be smaller, equal to, or larger than the sum of the minimum cross-sectional areas (and / or the sum of the maximum cross-sectional areas) of the multiple branch portions 55a. Regarding the shape, dimensions, etc. of the branch portion 55a, the description of the shape, dimensions, etc. of the hole 55A may be used, unless a contradiction arises.

[0136] Furthermore, for example, the area of ​​the opening of one hole 55B (junction 55b) on the top surface 7d is smaller than the arrangement area of ​​the multiple communication holes 23 corresponding to the one hole 55B. The arrangement area may be defined, for example, by the smallest convex polygon that surrounds the multiple communication holes 23 in a planar perspective view. This allows the area of ​​the opening on the top surface 7d to be smaller than, for example, an embodiment in which one straight columnar hole 55 is provided that overlaps the multiple communication holes 23, or an embodiment in which one straight columnar junction 55b is provided that overlaps the entirety of the multiple branch portions 55a (these embodiments are also included in the technology disclosed herein).

[0137] 11 , when the supply member 7 is bonded to the flow path member 3, the plurality of communication holes 23 (for example, all of the communication holes 23 of the flow path member 3) are blocked by the supply member 7. More specifically, for example, the plurality of communication holes 23 are blocked by the bonding surface 7c. As described above, the bonding surface 7c is bonded to the pressure surface 3b with an adhesive (not shown). Therefore, there is basically no gap between the bonding surface 7c and the pressure surface 3b, and the plurality of communication holes 23 are sealed.

[0138] (3.4.4. Other Examples) The hole 55 provided in the supply member 7 and opening the communication holes 23 may have a configuration other than that shown in Figures 9 and 10. For example, as already mentioned, a single straight columnar hole 55 (from another perspective, a single hole 55 without a branch portion 55a) may be provided that overlaps multiple communication holes 23 (for example, all or some of the communication holes 23 in a specific region; the same applies below). Furthermore, one branch portion 55a may overlap two or more communication holes 23.

[0139] 10 illustrates an example in which a predetermined number (two or more) of branch portions 55a are connected "individually" (one-to-one) to a predetermined number of communication holes 23. However, as mentioned above, at least one branch portion 55a may overlap two or more communication holes 23, so that a first number (a natural number greater than or equal to two) of branch portions 55a are connected to a second number of communication holes 23, which is greater than the first number. In such an example, the multiple branch portions 55a are expressed as being "separately" connected (not necessarily one-to-one) to the multiple communication holes 23. The same applies to components other than the branch portions 55a.

[0140] In the aspect in which the communication holes 23 are blocked, the member blocking the communication holes 23 is not limited to the supply member 7. For example, as already mentioned, the communication holes 23 may be blocked by the actuator 5. The communication holes 23 may also be blocked by being filled with adhesive, or by a member whose sole purpose is to block the communication holes 23. Some of the multiple communication holes 23 may be blocked by the supply member 7, and the rest may be blocked by any of the various components described above.

[0141] The configuration of the communication holes 23 of the flow path member 3 may be combined with the open or closed state of the communication holes 23 in any desired manner. For example, in FIG. 9 , a configuration in which all of the relief grooves 21 and all of the communication holes 23 are individually connected to each other is combined with a configuration in which all of the communication holes 23 are individually connected to all of the holes 55. However, for example, the flow path member 3 of FIG. 10 or 11 may be combined with a configuration in which all of the communication holes 23 are individually connected to all of the holes 55. Similarly, the supply member 7 of FIG. 10 (where the number of branch portions 55 a is changed depending on the number of communication holes 23) may be combined with the flow path member 3 of FIG. 9 or 11, or the supply member 7 of FIG. 11 may be combined with the flow path member 3 of FIG. 9 or 10.

[0142] (4. Specific Examples of Planar Shapes of Relief Grooves Near the Communication Holes) As already mentioned, the shape and dimensions of the relief grooves 21 are arbitrary. An example of a specific planar shape of the relief grooves 21 will be shown below.

[0143] 14 is a top view showing a part of the flow path part 15. In this figure, the relief grooves 21 located on the lower surface of the flow path part 15 are also shown by solid lines. In the description here, for convenience, it may be assumed that the relief grooves 21 are formed only on the lower surface of the flow path part 15. Therefore, for example, the relief grooves 21 of different flow path parts 15 refer to the relief grooves 21 between different layers 19.

[0144] The flow path part 15 illustrated in Fig. 14 is not the flow path part 15 in the uppermost layer, and has a flow path forming hole 31a that forms a portion of the common flow path 31 that extends upward (toward the +D3 side) toward the supply port 29, and an escape groove 21 located around the flow path forming hole 31a. In the example of Fig. 8, the illustrated flow path part 15 is one of flow path parts 15G to 15I. As can be understood from a comparison of the number and positions of the flow path forming holes 31a in Fig. 14 with the number and positions of the supply ports 29 in Fig. 6, Fig. 14 shows an enlarged view of a portion of the flow path part 15 on the +D2 side and the -D1 side.

[0145] The flow path part 15 has, for example, a first annular portion 21a surrounding the flow path forming hole 31a and a second annular portion 21b surrounding the first annular portion 21a as the relief groove 21. The first annular portion 21a is an example of the relief groove 21 that is not connected to the communication hole 23, and the second annular portion 21b is an example of the relief groove 21 that is connected to the communication hole 23. According to the above-mentioned definition that regards mutually connected relief grooves as one relief groove 21, the first annular portion 21a and the second annular portion 21b are mutually separate relief grooves 21.

[0146] The relief groove 21, including the second annular portion 21b, has a lattice portion 21c. The illustrated lattice portion 21c extends across roughly half of the flow path part 15 on the -D1 side (i.e., the area where the divided flow paths 12 corresponding to one color are arranged). As a result, with the exception of some relief grooves 21, such as the first annular portion 21a, various portions for the relief grooves are connected to each other to form a single relief groove 21. For example, four second annular portions 21b are connected to each other. Note that, when the flow path member 3 is configured to accommodate only one color of ink, the lattice portion 21c extends across roughly the entire flow path part 15.

[0147] The flow path part 15 has holes that become a plurality of communication holes 23 (for convenience, they may be described without being strictly distinguished from the communication holes 23). The communication holes 23 located in region XV are communication holes 23 that connect to the relief grooves 21 shown in FIG. 14. The other communication holes 23 (the communication holes 23 located on the −D1 side of region XV) are communication holes 23 that connect to the relief grooves 21 of the flow path part 15 located below (on the −D3 side of) the flow path part 15 in FIG. 14. On the +D1 side of region XV, the region surrounded by a circular portion 21d (described later) is a region that overlaps in planar perspective with the communication holes 23 that connect to the relief grooves 21 of the flow path part 15 located above (on the +D3 side of) the flow path part 15 in FIG. 14.

[0148] FIG. 15 is an enlarged view of region XV.

[0149] The relief groove 21 has a circular portion 21d, an arc-shaped portion 21e, two extension portions 21f, and a connection portion 21g around the communicating hole 23. The circular portion 21d is circular and has a center at the communicating hole 23. The arc-shaped portion 21e is arc-shaped and has a center at the communicating hole 23, and is located inside the circular portion 21d. The extension portions 21f extend from both ends of the arc-shaped portion 21e to two different positions on the circular portion 21d without intersecting each other. The connection portion 21g extends from between the two positions on the circular portion 21d, passing between the two extension portions 21f, and reaches the communicating hole 23.

[0150] The circular portion 21d is connected to a portion of the relief groove 21 that is located outside the circular portion 21d. In the illustrated example, the circular portion 21d is directly connected to the lattice portion 21c, and is also connected to other portions of the relief groove 21, such as the second annular portion 21b. The portion of the relief groove 21 that is located outside the circular portion 21d is connected to the communication hole 23 via the circular portion 21d and the connecting portion 21g. In addition, the arc-shaped portion 21e and the extension portion 21f that are located inside the circular portion 21d are also connected to the communication hole 23 via the circular portion 21d and the connecting portion 21g.

[0151] Such a planar shape of the relief groove 21 reduces the likelihood that excess adhesive 17 will flow from the periphery of the circular portion 21d into the communication hole 23 and block the communication hole 23. More detailed effects will be described in the summary of the embodiment.

[0152] The specific shape and dimensions of the above-described configuration of the relief groove 21 are arbitrary. For example, as long as the radius of the circular portion 21d is larger than the radius of the arc-shaped portion 21e, the specific sizes of the circular portion 21d and the arc-shaped portion 21e and the difference therebetween (the difference, ratio, etc.) are arbitrary. For example, the difference between the radii may be larger than the widths (e.g., maximum widths) of the circular portion 21d and the arc-shaped portion 21e and / or the diameter (e.g., maximum diameter) of the communicating hole 23. Furthermore, for example, the central angle of the arc-shaped portion 21e may be greater than 180°, 270° or greater, or 300° or greater.

[0153] Furthermore, for example, the two extension portions 21f may be linear and parallel to each other. However, the distance between the two extension portions 21f may become wider or narrower as they approach the circular portion 21d, or they may have curved or bent portions. The connecting portion 21g may pass through a midpoint between the two extension portions 21f. In the illustrated example, the connecting portion 21g extends parallel to the two extension portions 21f.

[0154] Returning to Figure 14, a circular portion 21d, an arc-shaped portion 21e, and two extensions 21f are provided around the communication holes 23 other than the communication hole 23 in region XV, similar to the periphery of the communication hole 23 in region XV. However, no connection portion 21g is provided. The same is true around the position of the communication hole 23 of the flow path part 15 above the flow path part 15 in Figure 14. Although not particularly shown, two or more circular portions 21d may be provided concentrically, or two or more arc-shaped portions 21e (and associated extensions 21f) may be provided concentrically.

[0155] (5. Summary of the embodiment) As described above, the liquid ejection head (head 2) according to the embodiment includes a flow path member 3. The flow path member 3 has a plurality of flow path parts 15 laminated via an adhesive 17. The flow path member 3 also has a flow path 11, a plurality of relief grooves 21, and a plurality of communication holes 23. The flow path 11 includes a plurality of nozzles 13. The plurality of relief grooves 21 are located in a plurality of interlayer spaces 19 between the plurality of flow path parts 15 and are spaced apart from the flow path 11. The plurality of communication holes 23 are connected to the plurality of relief grooves 21 and open on a first outer surface (pressure surface 3b) of the flow path member 3. Each of the plurality of communication holes 23 penetrates one or more flow path parts 15 in the stacking direction (direction D3) of the plurality of flow path parts 15 and reaches the pressure surface 3b located on one side in direction D3. The first relief groove between the first layers and the second relief groove between the second layers (for example, any two relief grooves 21 in FIG. 9) are connected to different communication holes 23, and are thereby isolated from each other.

[0156] From another perspective, the recording device (printer 1) according to the embodiment includes the head 2 according to the embodiment described above and a moving unit 85. The moving unit 85 moves the head 2 and a recording medium (print paper P) relative to each other. Liquid (ink) ejected from the multiple nozzles 13 lands on the print paper P.

[0157] Therefore, for example, the effects described in the summary of the embodiment are achieved. Specifically, it is easy to separately perform leak tests for at least one interlayer space 19 and at least another interlayer space 19. Furthermore, for example, by isolating the relief grooves 21 of different interlayer spaces 19 from each other, the likelihood that unintended fluid that has entered the relief groove 21 will spread to multiple relief grooves 21 is reduced.

[0158] The first relief groove between the first layers (for example, any relief groove 21 in Figure 9 and a relief groove 21 connected to a communicating hole 23 other than communicating hole 23N in Figure 10) may be isolated from the relief grooves 21 between all layers 19 other than the first layer.

[0159] In this case, for example, at least one escape groove 21 between the first layers can be inspected for leaks separately from the escape grooves 21 between all other layers 19. As a result, for example, it is possible to evaluate with high accuracy whether there is an excess or deficiency of adhesive 17 between specific layers 19 (for example, between layers 19 that have a large impact on the ejection characteristics of the head 2). Consequently, errors in the shape of the flow path 11 are reduced, and the ejection characteristics are stabilized.

[0160] All of the relief grooves 21 connected to at least one of the plurality of communication holes 23 may be isolated from the relief grooves 21 in all interlayer spaces 19 other than the one in question (see, for example, FIG. 9).

[0161] In this case, for example, leak testing can be performed individually for all interlayer spaces 19. As a result, it is possible to evaluate with even greater precision whether the adhesive 17 is excessive or insufficient. In addition, the likelihood of unintended fluid flow between the relief grooves 21 is reduced.

[0162] An inter-layer space 19 between two flow path parts 15 having different planar shapes related to the flow path 11 (e.g., inter-layer spaces 19L to 19N and 19Q in FIG. 10 ) is referred to as a third inter-layer space. An inter-layer space 19 between two flow path parts 15 having the same planar shape related to the flow path 11 (e.g., inter-layer spaces 19O and 19P in FIG. 10 ) is referred to as a fourth inter-layer space. In this case, all of the relief grooves 21 connected to any of the multiple communication holes 23 in all of the third inter-layer spaces are connected to different communication holes 23 and are isolated from each other. Furthermore, all of the relief grooves 21 connected to any of the multiple communication holes 23 in all of the third inter-layer spaces are also isolated from the relief grooves 21 in the fourth inter-layer space (inter-layer spaces 19O and 19P for inter-layer spaces 19L and 19M as the third inter-layer spaces) formed by two flow path parts 15 having planar shapes related to the flow path 11 that are different from those of either of the two flow path parts 15 constituting the inter-layer space 19 itself.

[0163] For example, even if the adhesive 17 is applied to the same thickness between the layers 19 of the flow path parts 15 having different planar shapes related to the flow paths 11, differences in the amount of excess or deficiency of the adhesive 17 are likely to occur. Therefore, by connecting the multiple relief grooves 21 to the multiple communication holes 23 as described above, the layers 19 that are likely to have differences in the amount of excess or deficiency of the adhesive 17 can be evaluated separately from each other. This in turn makes it easy to reduce errors in the shape of the flow paths 11.

[0164] In the embodiment in which the third and fourth layers are connected by the communication hole 23 as described above, the relief groove 21 of at least one fourth layer (e.g., layers 19O and 19P in Figures 10 and 11) may be connected to a common communication hole 23 (e.g., communication hole 23N in Figure 10 or communication hole 23O in Figure 11) that is common to the relief groove 21 of a specific layer 19. The above-mentioned specific interlayer 19 may be at least one of at least one third interlayer (e.g., interlayer 19N and interlayer 19Q, referred to as the "fifth interlayer" in the next paragraph) formed by one flow path part 15 having the same shape related to the flow path 11 as the two flow path parts 15 that form the interlayer 19 itself, and at least one other fourth interlayer (e.g., the other of one of interlayers 19O and 19P, referred to as the "sixth interlayer" in the next paragraph) formed by two flow path parts 15 that form the interlayer 19 itself and two flow path parts 15 having the same shape related to the flow path 11.

[0165] In this case, for example, leak inspection can be performed on both interlayers 19 that are likely to have the same excess or deficiency of adhesive 17. As a result, leak inspection can be facilitated while ensuring the accuracy of leak inspection for each interlayer 19. Note that, between an embodiment in which the specific interlayer 19 includes the fifth interlayer (e.g., FIG. 10 ) and an embodiment in which the specific interlayer 19 includes only the sixth interlayer (e.g., FIG. 11 ), the latter is more effective in improving accuracy, and the former is more effective in facilitating inspection.

[0166] The flow path member 3 may have a longitudinal direction (D2 direction) and a lateral direction (D1 direction) when viewed in the stacking direction (D3 direction). The plurality of communication holes 23 may include two communication holes 23 connected to the same relief groove 21 (e.g., FIG. 12). The two communication holes 23 may be located at one end and the other end in the longitudinal direction, respectively.

[0167] In this case, even if the adhesive 17 clogs between one of the communication holes 23 and a portion of the relief groove 21 that is distant from the one of the communication holes 23, the expanded gas in the distant portion can be discharged through the other communication hole 23. Furthermore, compared to an embodiment in which only one communication hole 23 is provided (this embodiment is also included in the technology according to the present disclosure), it is easy to shorten the longest distance between each communication hole 23 and each portion of the relief groove 21. As a result, the likelihood of the adhesive 17 clogging two locations on the relief groove 21 and creating an airtight space therebetween is reduced. These factors improve the accuracy of the leak test compared to an embodiment in which only the amount of gas discharged from one communication hole 23 is measured.

[0168] The flow path 11 may have a plurality of individual flow paths 33 and (at least one) common flow path 31. The plurality of individual flow paths 33 may include a plurality of nozzles 13. The common flow path 31 may be connected to the plurality of individual flow paths 33. The minimum diameter of each of the plurality of communication holes 23 may be larger than the minimum width of the relief groove 21 to which it is connected, and may be equal to or larger than the minimum diameter (e.g., the minimum diameter of the orifice 37) of the portions (35, 37, 39, 41, and 43) of the plurality of individual flow paths 33 that are closer to the common flow path 31 than the plurality of nozzles 13.

[0169] In this case, for example, there is a reduced likelihood that the adhesive 17 will flow into the communicating hole 23 and clog the communicating hole 23. Normally, the amount of adhesive 17 is set so that the adhesive 17 will not clog the restrictor 37, the descender 43, etc., so if the minimum diameter of the communicating hole 23 is the size described above, the likelihood that the communicating hole 23 will be clogged with the adhesive 17 is sufficiently low.

[0170] The flow path member 3 may have a longitudinal direction (D2 direction) and a lateral direction (D1 direction) when viewed in the stacking direction (D3 direction). The openings of the plurality of communication holes 23 on the first outer surface (pressure surface 3b) may be arranged in two staggered rows along the lateral direction at one end of the longitudinal direction (see, for example, FIG. 6).

[0171] In this case, for example, it is easy to ensure a distance between the multiple communication holes 23. As a result, for example, it is easy to individually connect the multiple communication holes 23 to an instrument having multiple measurement flow paths connected to the multiple communication holes 23 for leak testing. For example, the likelihood of the multiple communication holes 23 and the instrument being misaligned and connecting communication holes 23 and measurement flow paths that do not correspond to each other is reduced.

[0172] The flow path 11 may have a first flow path and a second flow path (e.g., divided flow paths 12A and 12B in FIG. 13 ). The divided flow path 12A includes a portion of the multiple nozzles 13. The divided flow path 12B includes another portion of the multiple nozzles 13 (the sum of the first portion and the other portion is not necessarily all of the nozzles 13) and is isolated from the divided flow path 12A. The multiple relief grooves 21 may include a first flow path relief groove and a second flow path relief groove (e.g., relief grooves 21A and 12B in FIG. 13 ) in a predetermined interlayer space 19. The relief groove 21A may surround at least a portion of the portion of the divided flow path 12A located in the predetermined interlayer space 19. The relief groove 21B may surround at least a portion of the portion of the divided flow path 12B located in the predetermined interlayer space 19, and may be separated (isolated) from the relief groove 21A in the predetermined interlayer space 19. The relief grooves 21A and 21B may be connected to different communication holes 23 among the plurality of communication holes 23, and may thereby be isolated from each other.

[0173] In this case, for example, the probability that ink in the divided flow path 12A will infiltrate into the divided flow path 12B via the escape groove 21A, the communication hole 23, and the escape groove 21B is reduced, and as a result, the probability that two colors of ink will mix is ​​reduced.

[0174] The head 2 may further include an actuator 5 and a supply member 7. The actuator 5 may overlap the first outer surface (pressure surface 3b) and may apply pressure to the flow path 11. The supply member 7 may include a bonding surface 7c and a port (second port 27). The bonding surface 7c may be bonded to an area of ​​the pressure surface 3b where the actuator 5 is not disposed. The second port 27 may be connected to the flow path 11. The supply member 7 may have one or more holes 55. Each of the one or more holes 55 may open at the bonding surface 7c and be connected to at least one of the multiple communication holes 23, and may open at a second outer surface (upper surface 7d) of the supply member 7 other than the bonding surface 7c.

[0175] In this case, for example, when the flow path member 3 and the supply member 7 are heated in order to bond them with an adhesive, gas expanded in the escape groove 21 and the communication hole 23 can be discharged to the outside through the hole 55. As a result, for example, the likelihood that gas will get between the flow path member 3 and the supply member 7 and the bond strength between them will decrease is reduced.

[0176] At least one of the one or more holes 55 (for example, hole 55B in FIG. 10 ) may have two or more branch portions 55 a and a junction portion 55 b. The two or more branch portions 55 a may be connected separately (for example, individually) to two or more communication holes 23 among the plurality of communication holes 23. The junction portion 55 b may be configured by the joining of two or more branch portions 55 a, and may be open to the second outer surface (upper surface 7 d of the supply member 7).

[0177] In this case, for example, compared to an embodiment in which holes 55 are provided so as to overlap all of the plurality of communication holes 23 (this embodiment is also included in the technology according to the present disclosure), the opening area of ​​holes 55 on bonding surface 7c is reduced, making it easier to ensure the bonding area and the strength of the portion of supply member 7 in which holes 55 are provided. On the other hand, because branch portions 55a are concentrated on the top surface 7d side, it is easier to block holes 55 on top surface 7d compared to an embodiment in which holes 55A are provided separately for the plurality of communication holes 23 as shown in FIG.

[0178] The multiple flow path parts 15 may include a first flow path part (e.g., the flow path part 15M in FIG. 9 ) and a second flow path part (e.g., the flow path part 15L in FIG. 9 ). The flow path part 15M may include a first relief groove (relief groove 21). The flow path part 15L may include a second relief groove (relief groove 21). The thickness of the flow path part 15M in the stacking direction (direction D3) may be greater than the thickness of the flow path part 15L in the stacking direction. The minimum cross-sectional area of ​​the relief groove 21 of the flow path part 15M may be greater than the minimum cross-sectional area of ​​the relief groove 21 of the flow path part 15L. The sum of the minimum cross-sectional areas of one or more communication holes 23M connected to (one) relief groove 21 of the flow path part 15M may be greater than the sum of the minimum cross-sectional areas of one or more communication holes 23L connected to (one) relief groove 21 of the flow path part 15L.

[0179] In this case, for example, for a thin flow path part 15, the cross section of the relief groove 21 can be reduced to improve strength. On the other hand, for a thick flow path part 15, the cross section of the relief groove 21 can be increased to reduce the likelihood of clogging with adhesive 17. If the cross section of the relief groove 21 is large, the amount of gas expansion increases, but since the cross section of the communication hole 23 is also large, the gas can be quickly discharged, reducing the likelihood of poor bonding.

[0180] The first relief groove (e.g., the relief groove 21 in FIGS. 14 and 15 ) may have a circular portion 21d, an arc-shaped portion 21e, two extension portions 21f, and a connecting portion 21g. The circular portion 21d may be centered on the first communication hole (23) that connects to the first relief groove (21). The arc-shaped portion 21e may be centered on the first communication hole, have a radius smaller than the radius of the circular portion 21d, and have a central angle greater than 180°. The two extension portions 21f may extend from both ends of the arc-shaped portion 21e to two different positions on the circular portion 21d without intersecting each other. The connecting portion 21g may extend from between the two positions on the circular portion 21d, passing between the two extension portions 21f, and reach the first communication hole.

[0181] In this case, for example, the circular portion 21d, the arc-shaped portion 21e, and the two extension portions 21f reduce the likelihood that the adhesive 17 around them will flow into the communicating holes 23 and / or the connecting portions 21g, causing clogging. As a result, for example, the accuracy of leak testing is improved. By surrounding the communicating holes 23 with the circular portion 21d, the arc-shaped portion 21e, and the two extension portions 21f, i.e., by providing a double surrounding, the influence of the adhesive 17 around them on the communicating holes 23 can be reduced. Specifically, as can be seen from FIG. 14 , for example, the positional relationship between the circular portion 21d and the lattice portion 21c differs among the multiple communicating holes 23. Therefore, if the communicating holes 23 were surrounded only by the circular portion 21d, the influence of the adhesive 17 in the lattice portion 21c on the communicating holes 23 would differ depending on the above-mentioned positional relationship. However, by providing the arc-shaped portion 21e and the two extension portions 21f inside the circular portion 21d, the change in the influence described above can be alleviated.

[0182] 14 , the circular portion 21d, the arc-shaped portion 21e, and the two extensions 21f surrounding the other communication holes 23 located in regions other than region XV also have the same effect. However, because the other communication holes 23 are not connected to the relief grooves 21 of the flow path part 15 shown in FIG. 14 (because the connection portion 21g is not provided), other circular portions may be provided inside the circular portion 21d instead of the arc-shaped portion 21e and the two extensions 21f. Providing the arc-shaped portion 21e and the two extensions 21f for the other communication holes 23 as in the example of FIG. 14 may, for example, facilitate the fabrication (including design) of the flow path part 15 and / or facilitate the equalization of the effect of the adhesive 17 on the multiple communication holes 23.

[0183] 14 , the circular portion 21d, the arc-shaped portion 21e, and the two extensions 21f that surround the position of the communication hole 23 of the flow path part 15 located further above (from another perspective, they do not directly surround the communication hole 23) do not contribute to reducing the influence of the adhesive 17 on the communication hole 23. Therefore, the circular portion 21d, the arc-shaped portion 21e, and the two extensions 21f do not need to be provided. If these are provided, for example, it becomes easier to manufacture multiple flow path parts 15.

[0184] In the above embodiments, the head 2 is an example of a liquid ejection head. The printer 1 is an example of a recording device. The printing paper P is an example of a recording medium. Ink is an example of a liquid. The pressure surface 3b is an example of a first outer surface. The upper surface 7d of the supply member 7 is an example of a second outer surface. The divided flow path 12A is an example of a first flow path. The divided flow path 12A is an example of a second flow path. The relief groove 21A is an example of a relief groove for the first flow path. The relief groove 21B is an example of a relief groove for the second flow path. The second port 27 is an example of a port.

[0185] The technology according to the present disclosure is not limited to the above-described embodiments and may be implemented in various forms.

[0186] The liquid ejection head is not limited to a piezoelectric type that applies pressure to the liquid using a piezoelectric body, but may be, for example, a thermal type that applies pressure to the liquid by heating the liquid to generate bubbles.

[0187] The multiple flow path parts are not limited to being stacked in the normal direction of the ejection surface on which the multiple nozzles are opened. The multiple flow path parts may be stacked in a direction parallel to the ejection surface. Furthermore, the multiple flow path parts having the features of the embodiments do not need to constitute the entire flow path member. For example, the ejection surface may be formed by one or more plates parallel to the ejection surface, and multiple flow path parts stacked in a direction parallel to the ejection surface may be provided thereon. Furthermore, as can be understood from the above, the communication holes may be opened not on the outer surface (top surface) opposite the ejection surface but on an outer surface (side surface) facing a side of the ejection surface. Furthermore, in an embodiment in which the flow path parts are stacked in the normal direction of the ejection surface as in the embodiment, the communication holes may also be opened on the ejection surface.

[0188] The recording device may be one in which the recording medium and the head are moved relative to each other by moving the head using a robot or the like. The recording device may also be one in which the entire device is held and moved by a user's hand, moving relative to the recording medium. The recording device is not limited to one that applies ink to paper or cloth, etc., but may also be one that applies paint to a vehicle body. In other words, the recording medium may be interpreted broadly.

[0189] 2...liquid ejection head, 3...flow path member, 3b...pressure surface (first outer surface), 11...flow path, 13...nozzle, 15...flow path part, 17...adhesive, 21...relief groove, 23...communicating hole.

Claims

1. a flow path member having a plurality of flow path parts laminated with an adhesive; The flow path member is a flow path including a plurality of nozzles; a plurality of relief grooves located between the plurality of layers of the flow path parts and spaced apart from the flow path; a plurality of communication holes connected to the plurality of relief grooves and opening at the first outer surface of the flow path member, each of the plurality of communication holes penetrates one or more flow path parts in a stacking direction of the plurality of flow path parts and reaches the first outer surface located on one side of the stacking direction; Among the plurality of relief grooves, the first relief groove between the first layers and the second relief groove between the second layers are connected to different communication holes among the plurality of communication holes, and are thereby isolated from each other. Liquid ejection head.

2. The first relief groove is isolated from the relief grooves between all layers other than the first layer. The liquid ejection head according to claim 1 .

3. All of the relief grooves connected to the plurality of communication holes are isolated from the relief grooves between all layers other than the layer between which they are connected. The liquid ejection head according to claim 2 .

4. When a layer between two flow path parts having different planar shapes related to the flow paths is referred to as a third layer, and a layer between two flow path parts having the same planar shape related to the flow paths is referred to as a fourth layer, all of the relief grooves connected to any of the plurality of communication holes between all of the third layers are connected to different communication holes and are isolated from each other, and are also isolated from all of the relief grooves between all of the fourth layers constituted by two flow path parts having planar shapes related to the flow paths that are different from either of the two flow path parts constituting the layer between themselves. The liquid ejection head according to claim 1 .

5. The relief groove between at least one fourth layer is connected to a common communication hole with the relief groove between at least one third layer formed by one flow path part having the same shape related to the flow path as two flow path parts forming the interlayer itself, and at least one other fourth layer formed by two flow path parts having the same shape related to the flow path as two flow path parts forming the interlayer itself. The liquid ejection head according to claim 4 .

6. the flow path member has a longitudinal direction and a lateral direction when viewed in the stacking direction, the plurality of communication holes include two communication holes connected to the same relief groove, The two communication holes are located at one end and the other end in the longitudinal direction, respectively. The liquid ejection head according to claim 1 .

7. The flow path is a plurality of individual flow paths including the plurality of nozzles; a common flow path connected to the plurality of individual flow paths, The minimum diameter of each of the plurality of communication holes is larger than the minimum width of the relief groove connected to it, and is equal to or larger than the minimum diameter of the portion of the plurality of individual flow paths on the common flow path side relative to the plurality of nozzles. The liquid ejection head according to claim 1 .

8. the flow path member has a longitudinal direction and a lateral direction when viewed in the stacking direction, The openings of the plurality of communication holes in the first outer surface include a predetermined number of communication holes arranged in a staggered pattern in two rows along the short direction at one end in the longitudinal direction. The liquid ejection head according to claim 1 .

9. The flow path is a first flow path including a portion of the plurality of nozzles; a second flow path that includes another part of the plurality of nozzles and is isolated from the first flow path, The plurality of relief grooves are provided between predetermined layers. a first flow path relief groove surrounding at least a portion of the first flow path located between the predetermined layers; a second flow path relief groove surrounding at least a portion of the second flow path located between the predetermined layers and separated from the first flow path relief groove between the predetermined layers, The first flow path relief groove and the second flow path relief groove are connected to different communication holes among the plurality of communication holes, and are thereby isolated from each other. The liquid ejection head according to claim 1 .

10. an actuator overlying the first outer surface and applying pressure to the flow path; a supply member having a joining surface that is joined to the actuator non-arrangement region of the first outer surface and a port that is connected to the flow path; and the supply member has one or more holes; Each of the one or more holes opens at the joining surface and is connected to at least one of the plurality of communication holes, and opens at a second outer surface of the supply member other than the joining surface. The liquid ejection head according to claim 1 .

11. At least one of the one or more holes is two or more branch portions separately connected to at least some of the plurality of communication holes; a confluence portion formed by the two or more branch portions merging and opening to the second outer surface. The liquid ejection head according to claim 10.

12. The plurality of flow path parts include: a first flow path part having the first relief groove; a second flow path part having the second relief groove, a thickness of the first flow path part in the stacking direction is greater than a thickness of the second flow path part in the stacking direction; a minimum area of ​​a cross section of the first relief groove is greater than a minimum area of ​​a cross section of the second relief groove; The sum of the minimum cross-sectional areas of one or more of the plurality of communication holes that are connected to the first relief groove is greater than the sum of the minimum cross-sectional areas of one or more of the plurality of communication holes that are connected to the second relief groove. The liquid ejection head according to claim 1 .

13. The first relief groove is a circular portion having a center at a first communication hole that is connected to the first relief groove among the plurality of communication holes; an arc-shaped portion having a center at the first communication hole, a radius smaller than the radius of the circular portion, and a central angle exceeding 180°; two extensions extending from both ends of the arc-shaped portion to two different positions on the circular portion without intersecting each other; a connecting portion that extends from between the two positions of the circular portion, passes between the two extension portions, and reaches the first communication hole. The liquid ejection head according to claim 1 .

14. A liquid ejection head according to any one of claims 1 to 13, a moving unit that moves the liquid ejection head and a recording medium relative to each other; A recording device having: