Liquid ejection head

Abstract

To provide a liquid ejection head that is able to cause a liquid to easily flow at a desired flow rate and able to restrict or prevent an occurrence of omission of ejection.SOLUTION: A liquid ejection head includes: a supply hole to which a liquid is supplied from outside; a plurality of supply manifolds disposed below the supply hole and communicating with the supply hole; and a partition wall separating adjacent one manifold and another manifold of the plurality of supply manifolds. Each of the plurality of supply manifolds has a manifold hole that is a portion located below the supply hole, and these manifolds communicate with one another in a common space below the partition wall. One of the manifold holes is disposed such that there are no other manifold holes on an extension line of the one of the manifold holes.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Patent Document 1 discloses a discharge head having a configuration in which four supply manifolds are connected to one supply hole, and bars are provided below the supply hole to separate each of the four supply manifolds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-206333 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above conventional configuration, the two outer supply manifolds among the four supply manifolds that communicate with the supply holes are not shaped to extend in one direction but are shaped to draw an arc, which may cause the flow to take a large detour. Therefore, when a common space that connects the supply manifolds is provided under the crosspiece, liquid stagnation occurs in the common space. As a result, air remains in the stagnation and pressure fluctuations are absorbed by the air, which may prevent the desired flow rate from being achieved. In addition, when the air flows downstream of the supply manifold, it may block the nozzle and cause missed discharge.

[0005] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS An object of the present invention is to provide a liquid ejection head that can easily cause liquid to flow at a desired flow rate and can suppress or prevent the occurrence of missed ejections. [Means for solving the problem]

[0006] The liquid ejection head of the present invention comprises a supply hole through which liquid is supplied from the outside, a plurality of supply manifolds arranged below the supply hole and connected to the supply hole, and a partition wall separating adjacent supply manifolds from the other supply manifold of the plurality of supply manifolds, each of the plurality of supply manifolds having a manifold hole located below the supply hole and connected to each other in a common space below the partition wall, and one of the manifold holes is arranged such that no other manifold hole is present on the extension line of the one manifold hole in the extension direction of the supply manifold.

[0007] According to the present invention, since one manifold hole is arranged such that no other manifold hole is on the extension line of the one manifold hole in the extension direction of the supply manifold, stagnation of liquid supplied from the supply holes is unlikely to occur. This makes it possible to prevent a situation in which air remains due to stagnation and pressure fluctuations are absorbed by the air, making it impossible to flow a desired flow rate downstream of each supply manifold. It is also possible to prevent the air from flowing downstream of each supply manifold and clogging the nozzles, resulting in missed ejection. Effect of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection head that can easily cause liquid to flow at a desired flow rate and can suppress or prevent the occurrence of missing ejection. [Brief description of the drawings]

[0009] [Figure 1] 1 is a plan view showing a schematic configuration of a liquid ejection device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing the configuration of the liquid ejection head of FIG. [Diagram 3] FIG. 4 is a perspective view showing a manifold hole and a supply hole. [Figure 4] FIG. 4 is a plan view showing manifold holes, supply holes, and partition walls. [Diagram 5] 13A is an analysis result showing the air distribution in the manifold holes of the first embodiment at time T1, and FIG. 13B is an analysis result showing the air distribution in the same manifold holes at time T2. [Figure 6] 13(a) is an analysis result showing the air distribution in the manifold holes of the comparative example at T1, and (b) is an analysis result showing the air distribution in the same manifold holes at T2. [Figure 7] FIG. 11 is a plan view showing manifold holes and partition walls according to a second embodiment. [Figure 8] 13(a) is an analysis result showing the air distribution in the manifold holes of the second embodiment at time T1, and (b) is an analysis result showing the air distribution in the same manifold holes at time T2. [Figure 9] FIG. 13 is a plan view showing a modified example of a manifold hole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A liquid ejection head according to an embodiment of the present invention will be described below with reference to the drawings. The liquid ejection head described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiment, and additions, deletions, and modifications are possible without departing from the spirit of the present invention.

[0011] (First embodiment) 1, a liquid ejection head 20 of this embodiment is provided in a liquid ejection device 10. In addition to the liquid ejection head 20 that ejects liquid, this liquid ejection device 10 also includes a storage tank 12, a carriage 16, a pair of transport rollers 15, a pair of guide rails 17, and a sub-tank 18. In the liquid ejection device 10, an ejection receiving medium W, such as printing paper, is placed on a platen (not shown).

[0012] A liquid ejection head 20 and a sub-tank 18 are mounted on the carriage 16. The carriage 16 is supported by a pair of guide rails 17 extending in a main scanning direction perpendicular to the transport direction (sub-scanning direction) of the ejection receiving medium W, and reciprocates in the main scanning direction along the guide rails 17. This causes the liquid ejection head 20 to reciprocate in the main scanning direction. The liquid ejection head 20 is connected to the storage tank 12 via a tube 12a.

[0013] The pair of transport rollers 15 are disposed parallel to each other along the main scanning direction. The transport rollers 15 rotate when a transport motor (not shown) is driven, thereby transporting the ejection receiving medium W on the platen in the transport direction.

[0014] Ink, which is an example of a liquid, is stored in the storage tank 12. The storage tank 12 is connected to the liquid ejection head 20 via a tube 12a to supply liquid to the liquid ejection head 20. When the liquid is ink, a storage tank 12 is provided for each type of ink. For example, four storage tanks 12 are provided, each storing black, yellow, cyan, and magenta ink. The following description will be given of the case where ink is used as the liquid.

[0015] Next, the cross-sectional structure of the liquid ejection head 20 will be described. FIG. 2 is a cross-sectional view showing the structure of the liquid ejection head 20. As shown in FIG. 2, the liquid ejection head 20 has a plurality of nozzles 21 that eject droplets using ink from the storage tank 12. The liquid ejection head 20 has a laminate of a flow path forming body and a volume changing section. An ink flow path is formed inside the flow path forming body, and a plurality of nozzle holes 21a are opened in the ejection surface 40a, which is the lower surface of the flow path forming body. The volume changing section is driven to change the volume of the ink flow path. At this time, the meniscus vibrates in the nozzle hole 21a, and ink is ejected.

[0016] The above-mentioned flow path forming body of the liquid ejection head 20 is a laminate of multiple plates, and the volume changing portion includes a vibration plate 55 and an actuator (piezoelectric element) 60. An insulating film 56 is connected to the top of the vibration plate 55, and a common electrode 61 (described later) is connected to the top of the insulating film 56.

[0017] The multiple plates are stacked including, from bottom to top, a nozzle plate 46, a spacer plate 47, a first flow path plate 48, a second flow path plate 49, a third flow path plate 50, a fourth flow path plate 51, a fifth flow path plate 52, a sixth flow path plate 53, and a seventh flow path plate 54.

[0018] Holes and grooves of various sizes are formed in each plate. Inside the flow path forming body where the plates are stacked, the holes and grooves are combined to form a plurality of nozzles 21, a plurality of individual flow paths 64, and a supply manifold 22 as ink flow paths.

[0019] The nozzles 21 are formed penetrating the nozzle plate 46 in the stacking direction. In the ejection surface 40a of the nozzle plate 46, a plurality of nozzle holes 21a, which are the tips of the nozzles 21, are arranged in an arrangement direction to form a nozzle row. The arrangement direction is perpendicular to the stacking direction.

[0020] The supply manifold 22 supplies ink to pressure chambers 28 (described later) to which an ink ejection pressure is applied. The supply manifold 22 extends in the arrangement direction, and is connected to one end of each of the individual flow paths 64. That is, the supply manifold 22 functions as a common flow path for the ink. The supply manifold 22 is formed with through holes penetrating the first flow path plate 48 to the fourth flow path plate 51 in the stacking direction, and a recess recessed from the lower surface of the fifth flow path plate 52, which are overlapped in the stacking direction.

[0021] The nozzle plate 46 is disposed below the spacer plate 47. The spacer plate 47 is formed of, for example, stainless steel. The spacer plate 47 has a recess 45 in which a thin portion constituting a damper portion 47a and a damper space 47b are formed by being recessed in the thickness direction of the spacer plate 47 from the surface on the nozzle plate 46 side by, for example, half etching. With this configuration, a damper space 47b is formed as a buffer space between the supply manifold 22 and the nozzle plate 46.

[0022] The multiple individual flow paths 64 are each connected to the supply manifold 22. The upstream end of each individual flow path 64 is connected to the supply manifold 22, and the downstream end is connected to the base end of the nozzle 21. Each individual flow path 64 is composed of a first communication hole 25, a supply throttle path 26 which is an individual throttle path, a second communication hole 27, a pressure chamber 28, and a descender 29, and these components are arranged in this order.

[0023] The lower end of the first communication hole 25 is connected to the upper end of the supply manifold 22, extends upward in the stacking direction from the supply manifold 22, and penetrates an upper portion of the fifth flow path plate 52 in the stacking direction.

[0024] The upstream end of the supply throttle path 26 is connected to the upper end of the first communication hole 25. The supply throttle path 26 is formed by, for example, half etching, and is configured as a groove recessed from the lower surface of the sixth flow path plate 53. In addition, the upstream end of the second communication hole 27 is connected to the downstream end of the supply throttle path 26, extends upward in the stacking direction from the supply throttle path 26, and is formed so as to penetrate the sixth flow path plate 53 in the stacking direction.

[0025] The upstream end of the pressure chamber 28 is connected to the downstream end of the second communication hole 27. The pressure chamber 28 is formed to penetrate the seventh flow path plate 54 in the stacking direction.

[0026] The descender 29 is formed penetrating the spacer plate 47, the first flow path plate 48, the second flow path plate 49, the third flow path plate 50, the fourth flow path plate 51, the fifth flow path plate 52, and the sixth flow path plate 53 in the stacking direction. The descender 29 has an upstream end connected to the downstream end of the pressure chamber 28 and a downstream end connected to the base end of the nozzle 21. The nozzle 21 overlaps the descender 29 in the stacking direction, for example, and is disposed in the center of the descender 29 in the width direction.

[0027] The vibration plate 55 is laminated on the seventh flow path plate 54 and covers the upper openings of the pressure chambers 28.

[0028] The actuator 60 includes a common electrode 61, a piezoelectric layer 62, and an individual electrode 63, which are arranged in this order. The common electrode 61 covers the entire surface of the vibration plate 55 via the insulating film 56. The piezoelectric layer 62 covers the entire surface of the vibration plate 55 via the insulating film 56 and the common electrode 61. The individual electrodes 63 are provided for each pressure chamber 28, and are arranged on the piezoelectric layer 62. One individual electrode 63, the common electrode 61, and a portion of the piezoelectric layer 62 sandwiched between the two electrodes constitute one actuator 60.

[0029] The individual electrodes 63 are electrically connected to a driver IC. This driver IC receives a control signal from a control unit (not shown) to generate a drive signal (voltage signal) and apply it to the individual electrodes 63. In contrast, the common electrode 61 is always held at ground potential. In this configuration, the active portion of the piezoelectric layer 62 expands and contracts in the planar direction together with the two electrodes 61, 63 in response to the drive signal. Accordingly, the vibration plate 55 deforms in cooperation with the electrode 61, changing in a direction to increase or decrease the volume of the pressure chamber 28. As a result, an ejection pressure for ejecting ink from the nozzle 21 is applied to the pressure chamber 28.

[0030] In the liquid ejection head 20 as described above, when the pump is driven, ink flows from the subtank 18 into the supply manifold 22 via the supply hole 24. Then, the ink flows from the supply manifold 22 into the supply throttle passage 26 via the first communication hole 25, and flows from the supply throttle passage 26 into the pressure chamber 28 via the second communication hole 27. Then, the ink flows through the descender 29 and into the nozzle 21. Here, when an ejection pressure is applied to the pressure chamber 28 by the actuator 60, ink is ejected from the nozzle hole 21a.

[0031] Next, the multiple manifold holes 70 communicating with the supply holes 24 and the partition walls 72 separating adjacent manifold holes 70 will be described with reference to the drawings.

[0032] Fig. 3 is a perspective view showing manifold hole 70 and supply hole 24, and Fig. 4 is a plan view showing manifold hole 70, supply hole 24, and partition wall 72. Note that supply hole 24, supply manifold 22, and manifold hole 70, which will be described later, are liquid flow paths and are hollow, but in Figs. 3 and 4, the cavities are shown by outlines to make it easier to understand.

[0033] 3, the liquid ejection head 20 is supplied with liquid and has a supply hole 24, for example, square in plan view. The supply hole 24 is connected to the sub-tank 18 via a pipe. The supply hole 24 is formed, for example, in a cylindrical shape, and is provided at one end in the arrangement direction (extension direction of the supply manifold 22).

[0034] Here, a plurality of supply manifolds 22 are arranged below the supply holes 24. In this embodiment, for example, four supply manifolds 22a, 22b, 22c, and 22d are arranged as the plurality of supply manifolds 22, and extend in this order in the arrangement direction. Adjacent supply manifolds among the supply manifolds 22a, 22b, 22c, and 22d are partitioned by partition walls 72. In this embodiment, the dimension of the supply holes 24 in the width direction, which is a direction perpendicular to the arrangement direction, is smaller than the dimension from the outer end of the supply manifold 22a at one end in the width direction to the outer end of the supply manifold 22d at the other end in the width direction. This reduces the size of the supply holes 24.

[0035] Each supply manifold 22 has a manifold hole 70 that communicates with the supply hole 24. The supply manifolds 22a, 22b, 22c, and 22d have manifold holes 70a, 70b, 70c, and 70d, respectively. In this embodiment, the manifold holes 70a, 70b, 70c, and 70d are each long in the arrangement direction. Furthermore, each manifold hole 70 extends obliquely with respect to the arrangement direction. Specifically, in FIG. 4, an inner line, which is a part of the outer line defining the manifold hole 70a, extends obliquely with respect to the arrangement direction. One line defining the manifold hole 70b extends parallel to the arrangement direction, while the other line extends obliquely with respect to the arrangement direction. Furthermore, one line defining the manifold hole 70c extends parallel to the arrangement direction, while the other line extends obliquely with respect to the arrangement direction. Furthermore, a part of the inner line and the outer line defining the manifold hole 70d extends obliquely with respect to the arrangement direction. In this configuration, partition wall 72 separating manifold holes 70a and 70b extends obliquely with respect to the arrangement direction, partition wall 72 separating manifold holes 70b and 70c extends parallel to the arrangement direction, and partition wall 72 separating manifold holes 70c and 70d extends obliquely with respect to the arrangement direction. In this embodiment, manifold holes 70a, 70b, 70c, and 70d have a shape in which their widths become wider in stages in the arrangement direction.

[0036] Manifold holes 70a, 70b, 70c, and 70d are located below supply holes 24. Manifold holes 70a, 70b, 70c, and 70d each communicate with supply holes 24. This allows supply manifolds 22a, 22b, 22c, and 22d to communicate with supply holes 24, respectively.

[0037] Supply manifolds 22a, 22b, 22c, and 22d communicate with each other through a common space 71 that is located below each partition wall 72. More specifically, manifold holes 70a, 70b, 70c, and 70d communicate with each other through common space 71. The width (length in the width direction) of common space 71 may be equal to or smaller than the dimension from the outer end of supply manifold 22a at one end in the width direction to the outer end of supply manifold 22d at the other end in the width direction among the four supply manifolds 22.

[0038] In this configuration, one manifold hole 70 is arranged such that other manifold holes 70 do not exist on an extension line of the one manifold hole 70 in the arrangement direction. That is, in the example of Figure 4, manifold hole 70a is arranged such that the other three manifold holes 70b, 70c, and 70d do not exist on an extension line of manifold hole 70a in the arrangement direction. The other three manifold holes 70b, 70c, and 70d are arranged in the same manner as manifold hole 70a.

[0039] The density of the liquid used in the liquid ejection head 20 having the above-mentioned configuration is 1000 kg / m 3 ~2000kg / m 3 It is desirable that the viscosity of the liquid is between 3 mPa·s and 8 mPa·s. It is desirable that the surface tension of the liquid is between 20 mN / m and 40 mN / m. Furthermore, it is desirable that the supply negative pressure, which is the pressure applied to the nozzle side when introducing the liquid, is between 70 KPa and 90 KPa.

[0040] Here, an analysis was performed on the flow of liquid from the supply holes 24 to the manifold holes 70 in the liquid ejection head 20 of this embodiment. In the analysis results, the flow of air (pressure) is displayed instead of the flow of liquid. The analysis results will be explained together with the analysis results of a comparative example. FIG. 5(a) is the analysis result showing the air distribution in the manifold holes 70 of the first embodiment at time T1, and FIG. 5(b) is the analysis result showing the air distribution in the same manifold holes 70 at time T2 (>T1). FIG. 6(a) is the analysis result showing the air distribution in the manifold holes of the comparative example (the configuration of Patent Document 1) at time T1, and FIG. 6(b) is the analysis result showing the air distribution in the same manifold holes at time T2 (>T1).

[0041] As shown in Fig. 5(a), in the liquid ejection head 20 of this embodiment, it can be confirmed that the air region AR1 flows almost evenly through the manifold holes 70a, 70b, 70c, and 70d at time T1, and that no air bubbles are present. Also, as shown in Fig. 5(b), it can be confirmed that the air region AR2 flows almost evenly through the manifold holes 70a, 70b, 70c, and 70d over time, and that no air bubbles are present, even at time T2.

[0042] In contrast, in the comparative example, as shown in Fig. 6(a), it can be seen that at time T1, an air region AR4 indicating air bubbles exists within the region surrounded by air region AR3. Also, as shown in Fig. 5(b), it can be seen that even at time T2, air regions AR6 and AR7 indicating air bubbles exist near air region AR5. From the above, it can be seen that in the configuration of the comparative example, there are regions where it is difficult for the air flow vector to point in any direction, as shown by the air regions AR4, AR6, and AR7, and therefore stagnation occurs.

[0043] As described above, according to the liquid ejection head 20 of this embodiment, one manifold hole 70 is arranged so that there is no other manifold hole 70 on the extension line of the one manifold hole 70 in the extension direction of the supply manifold 22, so that stagnation of the liquid supplied from the supply holes 24 is unlikely to occur. This makes it possible to prevent a situation in which air remains due to stagnation and pressure fluctuations are absorbed by the air, making it impossible to flow a desired flow rate downstream of each supply manifold 22. It is also possible to prevent the air from flowing downstream of each supply manifold 22 and blocking the nozzles 21, resulting in missed ejection.

[0044] Furthermore, in this embodiment, there are four manifold holes 70. In this regard, it is difficult in design to arrange more than four manifold holes 70 for one supply hole 24. By providing four holes, ease of manufacture can be ensured.

[0045] In this embodiment, the manifold holes 70 are long in the extending direction, which makes it more difficult for stagnation to occur.

[0046] In this embodiment, the dimension of supply hole 24 in the width direction is smaller than the dimension from the outer end of supply manifold 22a at one end in the width direction to the outer end of supply manifold 22d at the other end in the width direction among the four supply manifolds 22. By making supply holes 24 as small as possible in this way, the interval between adjacent supply holes 24 can be ensured to be at least a certain value, which makes it easier to maintain the flatness of the plate when forming supply holes 24 in the plate by punching. Also, an increase in cost due to an increase in size of supply holes 24 can be avoided.

[0047] In this embodiment, some of the ridge lines in a plan view that define each manifold hole 70 extend obliquely relative to the arrangement direction. This allows the liquid to spread in the width direction and flow more easily into the common space than in an embodiment in which the manifold holes 70 extend parallel to the arrangement direction. This makes it easier to expel air.

[0048] In this embodiment, the manifold holes 70 have a shape in which their width increases stepwise in the arrangement direction. In this case, the sizes of the manifold holes 70 differ in the arrangement direction, creating areas where the flow is fast and areas where the flow is slow, making it easier to generate a flow toward the common space 71.

[0049] In this embodiment, the density of the liquid is 1000 kg / m 3 ~2000kg / m 3 It is desirable that the viscosity of the liquid is between 3 mPa·s and 8 mPa·s. It is desirable that the surface tension of the liquid is between 20 mN / m and 40 mN / m. These factors lead to the stabilization of ink ejection. Specifically, this improves the accuracy of ejection, making it less likely that non-ejection, deflected ejection, or insufficient ejection volume will occur.

[0050] Furthermore, in this embodiment, the negative supply pressure of the liquid is desirably 70 KPa to 90 KPa. If the negative supply pressure, which is the pressure applied to the nozzle 21 side when introducing the liquid, is too high, air will remain, and if it is too low, the supply of the liquid will be slow. By setting the negative supply pressure in the above range, the above problems can be made less likely to occur.

[0051] Second embodiment FIG. 7 is a plan view showing the manifold holes 81 and partition walls 82 according to the second embodiment. In FIG. 7, the inner line defining the manifold hole 81a extends parallel to the arrangement direction. One line and the other line defining the manifold hole 81b extend parallel to the arrangement direction. Moreover, one line and the other line defining the manifold hole 81c extend parallel to the arrangement direction. Furthermore, the inner line defining the manifold hole 81d extends parallel to the arrangement direction. In this configuration, in the second embodiment, the partition wall 82 that partitions the manifold holes 81a and 81b extends parallel to the arrangement direction, the partition wall 82 that partitions the manifold holes 81b and 81c extends parallel to the arrangement direction, and the partition wall 82 that partitions the manifold holes 81c and 81d extends parallel to the arrangement direction. Note that the reference numeral 83 denotes a common space.

[0052] As in the first embodiment, an analysis was performed on the flow of liquid from the supply holes 24 to the manifold holes 81 in the liquid ejection head 20. Fig. 8(a) shows the analysis result indicating the air distribution in the manifold holes 81 of the second embodiment at T1, and Fig. 8(b) shows the analysis result indicating the air distribution in the same manifold holes 81 at T2 (>T1).

[0053] As shown in FIG. 8(a), in the liquid ejection head 20 of this embodiment, it can be confirmed that the air region AR8 flows almost evenly through the manifold holes 81a, 81b, 81c, and 81d at time T1. On the other hand, it can be confirmed that the air region AR9 indicating air bubbles exists. Also, as shown in FIG. 8(b), it can be confirmed that the air region AR10 flows almost evenly through the manifold holes 81a, 81b, 81c, and 81d as time passes, even at time T2, but it can be confirmed that the air region AR11 indicating air bubbles still exists. It can be confirmed that after the state of FIG. 8(b) (i.e., T3>T2), the air region AR11 disappears and the air bubbles in the common space are removed. From the above, it can be said that the aspect of the first embodiment is more desirable from the viewpoint of making it difficult for air bubbles to occur.

[0054] (Modification) The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention. For example, the following modifications are possible.

[0055] In the above embodiment, the manifold holes 70a, 70b, 70c, and 70d have a shape in which the width gradually increases in the arrangement direction, but this is not limited to the above. As shown in FIG. 9, each manifold hole 91 (91a, 91b, 91c, and 91d) of each supply manifold 90 (90a, 90b, 90c, and 90d) may have a shape in which the width gradually decreases in the arrangement direction. As a result, the size of each manifold hole 91 differs in the arrangement direction, resulting in places where the flow is fast and places where the flow is slow, which makes it easier to generate a flow toward the common space. Note that reference numeral 92 denotes a partition wall that separates adjacent manifold holes 91, and reference numeral 93 denotes a common space.

[0056] In the above embodiment, the width of the common space 71 is set to be equal to or smaller than the dimension from the outer end of the supply manifold 22a at one end in the width direction to the outer end of the supply manifold 22d at the other end in the width direction among the four supply manifolds 22, but this is not limited to this. The common space 71 may have a width larger than the dimension from the outer end of the supply manifold 22a at the one end to the outer end of the supply manifold 22d at the other end.

[0057] Furthermore, in the above embodiment, the supply hole 24 is formed in a square shape, but this is not limiting, and the supply hole 24 may be formed in, for example, a circular shape. [Explanation of symbols]

[0058] 10 Liquid dispensing device 20 Liquid ejection head 21 Nozzle 22, 22a, 22b, 22c, 22d Supply manifold 24 Supply hole 70, 70a, 70b, 70c, 70d Manifold holes 71,83,93 Common space 72,82,92 Ward bulkhead 80,80a,80b,80c,80d Supply manifold 81, 81a, 81b, 81c, 81d Manifold holes 90,90a,90b,90c,90d Supply manifold 91, 91a, 91b, 91c, 91d Manifold holes

Claims

1. A liquid ejection head having a laminate, A supply hole through which liquid is supplied from the outside; a plurality of supply manifolds disposed below the supply holes and communicating with the supply holes; a partition wall that partitions one adjacent supply manifold from the other adjacent supply manifold among the plurality of supply manifolds, each of the plurality of supply manifolds has a manifold hole that is a portion located below the supply hole in a stacking direction of the laminate, and is in communication with the respective manifolds through a common space located downstream of and adjacent to the partition wall in an arrangement direction that is a direction perpendicular to the stacking direction; A liquid ejection head, wherein one of the manifold holes is disposed such that no other manifold hole is present on an extension line of the one of the manifold holes in an extension direction of the supply manifold.

2. The liquid ejection head according to claim 1 , wherein the number of the manifold holes is four.

3. The liquid ejection head according to claim 1 , wherein the manifold hole is elongated in the extending direction.

4. A liquid ejection head as described in any one of claims 1 to 3, wherein when a direction intersecting the extension direction is defined as a width direction, a dimension of the supply hole in the width direction is smaller than a dimension from an outer end of a supply manifold at one end side in the width direction to an outer end of a supply manifold at the other end side in the width direction among the plurality of supply manifolds.

5. The liquid ejection head according to claim 1 , wherein the manifold hole extends obliquely with respect to the extending direction.

6. The liquid ejection head according to claim 1 , wherein the manifold hole has a width that gradually narrows or gradually widens in the extending direction.

7. The density of the liquid is 1000 kg / m ３ ~2000kg / m ３ The liquid ejection head according to claim 1 , wherein

8. 8. The liquid ejection head according to claim 1, wherein the liquid has a viscosity of 3 mPa·s to 8 mPa·s.

9. 9. The liquid ejection head according to claim 1, wherein the surface tension of the liquid is 20 mN / m to 40 mN / m.

10. 10. The liquid ejection head according to claim 1, wherein the liquid supply negative pressure is 70 KPa to 90 KPa.

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