Liquid ejection head and liquid ejection device

Abstract

To sufficiently remove thickened ink while achieving excellent ejection characteristics.SOLUTION: There is provided a liquid ejection head in which a piezoelectric element, a vibration plate, a first pressure chamber substrate, a second pressure chamber substrate, and a nozzle substrate are laminated in a lamination direction from top to bottom in this order. The first pressure chamber substrate has a first portion, a second portion separated from the first portion, and a third portion separated from the first portion and the second portion and located between the first portion and the second portion. The second pressure chamber substrate has a fourth portion and a fifth portion separated from the fourth portion. The first pressure chamber substrate includes a first pressure chamber partitioned by the first portion, the third portion and the fourth portion, and a second pressure chamber partitioned by the second portion, the third portion and the fifth portion. The second pressure chamber substrate includes a third pressure chamber partitioned by the third portion, the fourth portion and the fifth portion and communicating with the first pressure chamber, the second pressure chamber and a nozzle. The piezoelectric element is disposed commonly across the first pressure chamber, the second pressure chamber and the third pressure chamber.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] In a liquid ejection head such as a piezoelectric inkjet head, a piezoelectric element varies the pressure in a pressure chamber, thereby ejecting a liquid such as ink from a nozzle connected to the pressure chamber. For example, Patent Document 1 describes a liquid ejection head in which a communication plate, a pressure chamber substrate, a vibration plate, and a piezoelectric element are stacked in this order. In this liquid ejection head, a portion of a nozzle is provided in the communication plate, and a pressure chamber provided in the pressure chamber substrate is located directly above the nozzle. In addition, a circulation mechanism that circulates ink that has flowed through the pressure chamber is connected to this liquid ejection head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-72166 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, the nozzle is located directly below the pressure chamber, which has the advantage of improving ejection characteristics by transmitting the pressure applied by the piezoelectric element to the nozzle without loss, and using a thin substrate reduces the cross-sectional area of ​​the pressure chamber or the flow path in its vicinity, thereby increasing the flow rate and allowing for the effective removal of thickened ink.Thickened ink is ink whose viscosity increases directly above the nozzle as the solvent component at the gas-liquid interface of the nozzle evaporates and reduces.

[0005] However, in the configuration described in Patent Document 1, in the circulation flow path, the space in the communicating plate directly above the nozzle and the space in the pressure chamber substrate are continuous, and the cross-sectional area becomes locally large, which causes the flow rate to decrease locally, resulting in the problem that the thickened ink cannot be sufficiently removed. [Means for solving the problem]

[0006] In order to solve the above problems, a liquid ejection head according to a preferred aspect of the present disclosure is a liquid ejection head in which a piezoelectric element, a vibration plate that vibrates when driven by the piezoelectric element, a first pressure chamber substrate, a second pressure chamber substrate, and a nozzle substrate on which nozzles that eject liquid are provided are stacked in this order from top to bottom in a stacking direction, wherein the first pressure chamber substrate has a first portion, a second portion spaced apart from the first portion, and a third portion spaced apart from the first portion and the second portion and located between the first portion and the second portion, and the second pressure chamber substrate has a fourth portion, and a fifth portion spaced apart from the first portion, the third portion, and the fourth portion, and a second pressure chamber formed by a space within the first pressure chamber substrate and partitioned by the second portion, the third portion, and the fifth portion are provided in the first pressure chamber substrate, and a third pressure chamber partitioned by the third portion, the fourth portion, and the fifth portion is provided in the second pressure chamber substrate, and the first pressure chamber, the second pressure chamber, and the nozzle are connected to each other, and a common piezoelectric element is arranged across the first pressure chamber, the second pressure chamber, and the third pressure chamber.

[0007] A liquid ejection device according to a preferred aspect of the present disclosure includes the liquid ejection head according to the above aspect, and a control unit that controls the ejection operation from the liquid ejection head. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a liquid ejection device according to a first embodiment. [Figure 2] FIG. 1 is an exploded perspective view of a liquid ejection head according to a first embodiment. [Figure 3]FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 2 is an enlarged cross-sectional view showing a part of the liquid ejection head according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view taken along line BB in FIG. [Figure 6] 5 is a cross-sectional view taken along line CC in FIG. 4. [Figure 7] 1 is an enlarged cross-sectional view showing a part of the liquid ejection head of Comparative Example 1. FIG. [Figure 8] 10 is an enlarged cross-sectional view showing a part of the liquid ejection head of Comparative Example 2. FIG. [Figure 9] 10 is an enlarged cross-sectional view showing a part of the liquid ejection head of Comparative Example 3. FIG. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing a part of a liquid ejection head according to a second embodiment. [Figure 11] FIG. 10 is an enlarged cross-sectional view showing a part of a liquid ejection head according to a third embodiment. [Figure 12] 12 is a cross-sectional view taken along line BB in FIG. 11. [Figure 13] FIG. 10 is an enlarged cross-sectional view showing a part of a liquid ejection head according to a fourth embodiment. [Figure 14] 14 is a cross-sectional view taken along line CC in FIG. 13. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions and are shown schematically to facilitate understanding. Furthermore, the scope of the present disclosure is not limited to these embodiments unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0010] For convenience, the following description will use the mutually intersecting X-axis, Y-axis, and Z-axis as appropriate. In the following description, one direction along the X-axis is the X1 direction, and the direction opposite the X1 direction is the X2 direction. Similarly, the opposite directions along the Y-axis are the Y1 direction and the Y2 direction. Furthermore, the opposite directions along the Z-axis are the Z1 direction and the Z2 direction. The Z2 direction side is referred to as "up," and the Z1 direction side is referred to as "down." However, the relationship between the Z-axis and the vertical direction is not particularly limited and can be any. Furthermore, the X-axis, Y-axis, and Z-axis are typically perpendicular to each other, but are not limited thereto. For example, they may intersect at an angle between 80° and 100°.

[0011] 1. First embodiment 1-1. Schematic configuration of a liquid ejection device equipped with a liquid ejection head FIG. 1 is a schematic diagram showing an example of the configuration of a liquid ejection device 100 according to a first embodiment. The liquid ejection device 100 is an inkjet printing device that ejects ink, which is an example of a "liquid," as droplets onto a medium M. The medium M is typically printing paper. However, the medium M is not limited to printing paper, and may be a printing target made of any material, such as a resin film or fabric.

[0012] 1, the liquid ejection device 100 includes a liquid container 10, a control unit 20, a transport mechanism 30, a movement mechanism 40, a plurality of liquid ejection heads 50, and a circulation mechanism 70. These will be briefly described below in order based on FIG.

[0013] The liquid container 10 stores ink. Specific examples of the liquid container 10 include a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack made of flexible film, and an ink tank that can be refilled with ink. There are no particular limitations on the type of ink stored in the liquid container 10, and any type can be used.

[0014] The control unit 20 includes a processing circuit including one or more processors such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and a storage circuit such as a semiconductor memory, and controls the operation of each element of the liquid ejection device 100.

[0015] The transport mechanism 30 transports the medium M in a transport direction DM, which is the Y1 direction, under the control of the control unit 20. The movement mechanism 40 reciprocates the multiple liquid ejection heads 50 in the X1 and X2 directions under the control of the control unit 20. In the example shown in FIG. 1, the movement mechanism 40 has a substantially box-shaped transport body 41, called a carriage, that houses the multiple liquid ejection heads 50, and a transport belt 42 to which the transport body 41 is fixed. Note that in addition to the multiple liquid ejection heads 50, the transport body 41 may also be equipped with the aforementioned liquid container 10.

[0016] Each of the multiple liquid ejection heads 50 ejects ink supplied from the liquid container 10 via the circulation mechanism 70 from a respective one of multiple nozzles onto the medium M in the Z1 direction under the control of the control unit 20. This ejection is performed in parallel with the transport of the medium M by the transport mechanism 30 and the reciprocating movement of the multiple liquid ejection heads 50 by the movement mechanism 40, thereby forming an ink image on the surface of the medium M. Details of the liquid ejection heads 50 will be described later with reference to FIGS. 2 to 6. The number of liquid ejection heads 50 included in the liquid ejection device 100 is not limited to the example shown in FIG. 1 and may be any number, such as three or less, five or more, or even just one.

[0017] In the example shown in FIG. 1 , the liquid container 10 is connected to a plurality of liquid ejection heads 50 via a circulation mechanism 70. The circulation mechanism 70 supplies ink to the plurality of liquid ejection heads 50 and recovers ink discharged from the plurality of liquid ejection heads 50 for resupply to the plurality of liquid ejection heads 50. Although not shown, the circulation mechanism 70 includes, for example, a supply flow path for supplying ink to the liquid ejection heads 50, a recovery flow path for recovering ink discharged from the liquid ejection heads 50, and a pump for generating pressure for transporting the ink. By operating the circulation mechanism 70 in this manner, ink is circulated between each liquid ejection head 50 and the circulation mechanism 70, which makes it possible to suppress an increase in the viscosity of the ink and reduce the accumulation of air bubbles in the ink within each liquid ejection head 50.

[0018] As described above, in the liquid ejection device 100, the control unit 20 controls the ejection operation from the liquid ejection head 50. As a result, as will be described later, the reliability and ejection characteristics of the liquid ejection head 50 are superior to conventional ones, and it is possible to realize the liquid ejection device 100 that is excellent in reliability and ejection characteristics.

[0019] 1-2. Liquid ejection head Fig. 2 is an exploded perspective view of the liquid ejection head 50 according to the first embodiment. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. Fig. 3 shows a cross section of the liquid ejection head 50 cut along a plane along both the X-axis and the Z-axis.

[0020] Generally speaking, the liquid ejection head 50 is provided with a plurality of nozzles N, a reservoir RA, a plurality of first pressure chambers C1, a plurality of second pressure chambers C2, a plurality of third pressure chambers C3, a plurality of piezoelectric elements 55, an inlet port 59c, and an outlet port 59d. Note that, hereinafter, a set of the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 may be referred to as a pressure chamber C.

[0021] The multiple nozzles N are arranged along the Y axis. Each of the reservoirs RA and RB is a common liquid chamber that is continuous across the multiple nozzles N. Each of the pressure chambers C and piezoelectric elements 55 is provided for each nozzle N. Each of the first pressure chamber C1 and second pressure chamber C2 communicates with the nozzle N via a third pressure chamber C3. Each of the multiple pressure chambers C is filled with ink supplied from the reservoir RA. The piezoelectric element 55 varies the pressure of the ink in the pressure chamber C. When the piezoelectric element 55 varies the pressure of the ink in the pressure chamber C, ink is ejected from the nozzle N.

[0022] The inlet port 59c communicates with the reservoir RA. Ink is introduced into the reservoir RA from the circulation mechanism 70 via the inlet port 59c. The ink introduced into the reservoir RA from the inlet port 59c is used appropriately for ejection from each nozzle N. The outlet port 59d communicates with the reservoir RB. Ink that is not ejected from each nozzle N and that is stored in the reservoir RB is ejected from the outlet port 59d. The ink ejected from the outlet port 59d is collected in the circulation mechanism 70. In this way, ink is circulated between the liquid ejection head 50 and the circulation mechanism 70.

[0023] 2 and 3, the liquid ejection head 50 has a second pressure chamber substrate 51, a first pressure chamber substrate 52, a nozzle substrate 53, a vibration plate 54, a plurality of piezoelectric elements 55, a first absorbing member 56, a second absorbing member 57, a sealing plate 58, a case 59, a wiring board 60, and a drive circuit 61.

[0024] In the liquid ejection head 50, the piezoelectric element 55, the vibration plate 54, the first pressure chamber substrate 52, the second pressure chamber substrate 51, and the nozzle substrate 53 are stacked in this order from top to bottom in the stacking direction. That is, the piezoelectric element 55, the vibration plate 54, the first pressure chamber substrate 52, the second pressure chamber substrate 51, and the nozzle substrate 53 are stacked in this order in the Z1 direction. Hereinafter, the Z1 direction may be referred to as the "stacking direction."

[0025] Here, the second pressure chamber substrate 51 and the first pressure chamber substrate 52 form a flow path for supplying ink to the multiple nozzles N. In an area positioned in the Z2 direction from the laminate consisting of the second pressure chamber substrate 51 and the first pressure chamber substrate 52, a vibration plate 54, multiple piezoelectric elements 55, a first absorbing member 56, a second absorbing member 57, a sealing plate 58, a case 59, a wiring board 60, and a drive circuit 61 are installed. On the other hand, in an area positioned in the Z1 direction from the laminate, a nozzle substrate 53 is installed. The elements of the liquid ejection head 50 are joined to each other by, for example, adhesive or direct bonding.

[0026] The nozzle substrate 53 is provided with a plurality of nozzles N. Each of the plurality of nozzles N is a through-hole that allows ink to pass through, and ejects ink in response to the driving of the piezoelectric element 55. The nozzle substrate 53 is manufactured by processing a silicon single crystal substrate using semiconductor manufacturing techniques such as dry etching or wet etching. However, other known methods and materials may be used as appropriate for manufacturing the nozzle substrate 53. Furthermore, the cross-sectional shape of the nozzle N is typically circular, but is not limited thereto and may be a non-circular shape such as a polygonal or elliptical shape. Furthermore, the width of the nozzle N does not have to be constant.

[0027] The second pressure chamber substrate 51 is provided with flow paths 51a and 51b, a common supply flow path 51c, a common discharge flow path 51d, and a plurality of third pressure chambers C3. The flow path 51a and the common supply flow path 51c are elongated openings extending in the direction along the Y axis in a plan view seen along the Z axis, and are in communication with each other. The flow path 51b and the common discharge flow path 51d are elongated openings extending in the direction along the Y axis in a plan view seen along the Z axis, and are in communication with each other. Each of the plurality of third pressure chambers C3 is a through hole formed for each nozzle N.

[0028] The first pressure chamber substrate 52 is provided with a plurality of first pressure chambers C1, a plurality of second pressure chambers C2, a first absorption chamber DB, a second absorption chamber DA, and flow paths 52a and 52b. The plurality of first pressure chambers C1 are provided for each nozzle N and are arranged in the direction along the Y axis. Similarly, the plurality of second pressure chambers C2 are provided for each nozzle N and are arranged in the direction along the Y axis. Each of the first pressure chambers C1 and each of the second pressure chambers C2 is an elongated space extending in the direction along the X axis in a plan view. Furthermore, the second pressure chamber C2 is positioned in the X1 direction relative to the first pressure chamber C1. The flow paths 52a, 52b, the first absorption chamber DB, and the second absorption chamber DA are each provided in common to a plurality of nozzles N and are elongated openings extending in the direction along the Y axis in a plan view seen in the direction along the Z axis. The flow path 52a overlaps the flow path 51a in a plan view and is connected to the flow path 51a. The flow path 52b overlaps the flow path 51b in a plan view and is connected to the flow path 51b. The first absorption chamber DB is disposed between the first pressure chamber C1 and the flow path 52b. The second absorption chamber DA is disposed between the second pressure chamber C2 and the flow path 52a.

[0029] The second pressure chamber substrate 51 and the first pressure chamber substrate 52 are each manufactured by processing a silicon single crystal substrate using, for example, semiconductor manufacturing technology, in the same way as the nozzle substrate 53 described above. However, other known methods and materials may also be used as appropriate for manufacturing the second pressure chamber substrate 51 and the first pressure chamber substrate 52. There are no particular limitations on the thickness of each of the second pressure chamber substrate 51 and the first pressure chamber substrate 52, but it is preferably between 50 μm and 100 μm.

[0030] The second pressure chamber C2 is connected to both the third pressure chamber C3 and the common supply flow path 51c. Therefore, the second pressure chamber C2 is connected to the nozzle N via the third pressure chamber C3, and is connected to the flow path 51a via the common supply flow path 51c. On the other hand, the first pressure chamber C1 is connected to both the third pressure chamber C3 and the common discharge flow path 51d. Therefore, the first pressure chamber C1 is connected to the nozzle N via the third pressure chamber C3, and is connected to the flow path 51b via the common discharge flow path 51d. In this way, the third pressure chamber C3 is connected to the first pressure chamber C1, the second pressure chamber C2, and the nozzle N.

[0031] Here, the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 each extend in an extension direction along the X-axis, and multiple sets of the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 are arranged in an arrangement direction (Y-axis direction) that intersects with the extension direction.

[0032] As described above, the liquid ejection head 50 has a common supply flow path 51c and a common discharge flow path 51d. The common supply flow path 51c supplies ink to multiple sets of the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 in common. Meanwhile, the common discharge flow path 51d discharges ink from multiple sets of the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 in common. By providing the common supply flow path 51c and the common discharge flow path 51d in this manner, it is possible to smoothly supply liquid from the common supply flow path 51c to one of the first pressure chamber C1 and the second pressure chamber C2 of each set, and to smoothly discharge liquid from the other pressure chamber to the common discharge flow path 51d.

[0033] As described above, the liquid ejection head 50 has a first absorption chamber DB and a second absorption chamber DA. The first absorption chamber DB is in communication with the first pressure chamber C1 and is a space for absorbing the pressure generated by the piezoelectric element 55. On the other hand, the second absorption chamber DA is in communication with the second pressure chamber C2 and is a space for absorbing the pressure generated by the piezoelectric element 55. By providing such a first absorption chamber DB and second absorption chamber DA, unnecessary vibration of the liquid in the first pressure chamber C1 and the second pressure chamber C2 can be reduced. As a result, the ejection characteristics can be improved.

[0034] Here, the first absorption chamber DB overlaps with the common discharge flow path 51d in a plan view. Therefore, the common discharge flow path 51d also functions as a space for absorbing the pressure caused by the piezoelectric element 55, similar to the first absorption chamber DB. In this way, the first absorption chamber DB is formed by the space in the first pressure chamber substrate 52 and the space in the second pressure chamber substrate 51. Similarly, the second absorption chamber DA overlaps with the common supply flow path 51c in a plan view. Therefore, the common supply flow path 51c also functions as a space for absorbing the pressure caused by the piezoelectric element 55, similar to the second absorption chamber DA. In this way, the second absorption chamber DA is formed by the space in the first pressure chamber substrate 52 and the space in the second pressure chamber substrate 51. With the first absorption chamber DB and the second absorption chamber DA configured as described above, the volumes of the first absorption chamber DB and the second absorption chamber DA can be increased. As a result, unnecessary vibration of the liquid in the first pressure chamber C1 and the second pressure chamber C2 can be suitably reduced.

[0035] A diaphragm 54 is disposed on the surface of the first pressure chamber substrate 52 facing the Z2 direction. The diaphragm 54 is a plate-like member that can elastically vibrate, and vibrates when driven by a piezoelectric element 55. The diaphragm 54 has, for example, a first layer and a second layer, which are stacked in this order in the Z1 direction. The first layer is, for example, an elastic film made of silicon oxide (SiO2). The elastic film is formed, for example, by thermally oxidizing one surface of a silicon single crystal substrate. The second layer is, for example, an insulating film made of zirconium oxide (ZrO2). The insulating film is formed, for example, by forming a zirconium layer by sputtering and then thermally oxidizing the layer. Note that the diaphragm 54 is not limited to the configuration of the stacked first and second layers described above, and may be, for example, a single layer or three or more layers.

[0036] A plurality of piezoelectric elements 55 are arranged on the surface of the vibration plate 54 facing the Z2 direction. Each of the piezoelectric elements 55 is a passive element that deforms when a drive signal is supplied. Each of the piezoelectric elements 55 has an elongated shape extending in the direction along the X axis in a plan view. A plurality of piezoelectric elements 55 is provided for each nozzle N and arranged in the direction along the Y axis. Each piezoelectric element 55 is provided in common so as to span the corresponding first pressure chamber C1 and second pressure chamber C2. In other words, each piezoelectric element 55 overlaps across the corresponding first pressure chamber C1 and second pressure chamber C2 in a plan view. The configuration of the piezoelectric elements 55 will be described later with reference to FIGS. 4 to 6.

[0037] The first absorption member 56 is provided above the first absorption chamber DB and is a vibration absorber that absorbs pressure fluctuations of the ink inside the first absorption chamber DB. The first absorption member 56 includes a compliance substrate 56a and a weight 56b.

[0038] The compliance substrate 56a is a flexible plate-like member that is arranged on the surface of the first pressure chamber substrate 52 facing the Z2 direction so as to cover the first absorption chamber DB. The compliance substrate 56a constitutes the upper wall of the first absorption chamber DB. In the example shown in FIG. 3, the compliance substrate 56a is formed integrally with the vibration plate 54. Therefore, the compliance substrate 56a has the same layer structure as the vibration plate 54.

[0039] The weight 56b is a mass body that is placed on the surface of the compliance substrate 56a that faces the Z2 direction. By providing such a weight 56b, it is possible to adjust the resonance frequency and the like of the first absorbing member 56. In the example shown in FIG. 3, the weight 56b has the same layer structure as the piezoelectric element 55.

[0040] In this way, the first absorbing member 56 is formed of the same material as at least a part of the diaphragm 54 and the piezoelectric element 55. This makes it possible to realize the first absorbing member 56 while reducing manufacturing costs. Note that the compliance substrate 56a may be separate from the diaphragm 54, or may have a different layer structure from the diaphragm 54. Furthermore, the weight 56b may have a different layer structure from the piezoelectric element 55.

[0041] The second absorption member 57 is provided above the second absorption chamber DA and is a vibration absorber that absorbs pressure fluctuations of the ink in the second absorption chamber DA. The second absorption member 57 includes a compliance substrate 57a and a weight 57b.

[0042] The compliance substrate 57a is a flexible plate-like member that is arranged on the surface of the first pressure chamber substrate 52 facing the Z2 direction so as to cover the second absorption chamber DA. The compliance substrate 57a constitutes the upper wall of the second absorption chamber DA. In the example shown in FIG. 3, the compliance substrate 57a is formed integrally with the vibration plate 54. Therefore, the compliance substrate 57a has the same layer structure as the vibration plate 54.

[0043] The weight 57b is a mass body disposed on the surface of the compliance substrate 57a facing the Z2 direction. By providing such a weight 57b, it is possible to adjust the resonance frequency and the like of the second absorption member 57. In the example shown in FIG. 3, the weight 57b has the same layer structure as the piezoelectric element 55.

[0044] In this way, second absorption member 57 is formed of the same material as at least a part of diaphragm 54 and piezoelectric element 55. This makes it possible to realize second absorption member 57 while reducing manufacturing costs. Note that compliance substrate 57a may be separate from diaphragm 54, or may have a different layer structure from diaphragm 54. Furthermore, weight 57b may have a different layer structure from piezoelectric element 55.

[0045] The sealing plate 58 is a plate-like member installed on the surface of the vibration plate 54 facing the Z2 direction, and protects the multiple piezoelectric elements 55, the first absorption member 56, and the second absorption member 57, while reinforcing the mechanical strength of the vibration plate 54. The sealing plate 58 is made of, for example, a resin material. The surface of the sealing plate 58 facing the Z1 direction is provided with multiple recesses for forming sealed spaces S1, S2, and S3. The multiple piezoelectric elements 55 are housed in the sealed space S1. The second absorption member 57 is housed in the sealed space S2. The first absorption member 56 is housed in the sealed space S3.

[0046] The sealing plate 58 is also provided with flow channels 58a, 58b and a wiring hole 58c. Each of the flow channels 58a, 58b is provided in common to multiple nozzles N and is an elongated opening extending in the direction along the Y-axis in a plan view taken along the Z-axis. The flow channel 58a overlaps the flow channel 52a in a plan view and communicates with the flow channel 52a. The flow channel 58b overlaps the flow channel 52b in a plan view and communicates with the flow channel 52b. The wiring hole 58c is a through-hole for passing the wiring substrate 60 therethrough and extends in the direction along the Y-axis in a plan view taken along the Z-axis.

[0047] The case 59 is a case for storing ink to be supplied to the multiple pressure chambers C. The case 59 is made of, for example, a resin material. The case 59 is provided with flow paths 59a and 59b, an inlet 59c, an outlet 59d, and compliance substrates 59e and 59f.

[0048] The flow path 59a is a space that communicates with the flow path 52a described above, and together with the flow paths 51a and 52a, functions as a reservoir RA that stores ink to be supplied to the multiple pressure chambers C. The reservoir RA is in communication with the second pressure chamber C2 via the common supply flow path 51c. On the other hand, the flow path 59b is a space that communicates with the flow path 52b described above, and together with the flow paths 51b and 52b, functions as a reservoir RB that stores ink discharged from the multiple pressure chambers C. The reservoir RB is in communication with the first pressure chamber C1 via the common discharge flow path 51d.

[0049] The compliance substrate 59e is a flexible plate-like member that forms part of the wall surface of the flow path 59a and absorbs pressure fluctuations of the ink in the reservoir RA. On the other hand, the compliance substrate 59f is a flexible plate-like member that forms part of the wall surface of the flow path 59b and absorbs pressure fluctuations of the ink in the reservoir RB. Each of the compliance substrates 59e, 59f is made of, for example, a resin film and is fixed to the main body of the case 59 with an adhesive or the like. In the example shown in FIG. 3, a compliance space that allows deformation of the compliance substrates 59e, 59f is provided between the main body and the compliance substrates 59e, 59f, and each of the compliance substrates 59e, 59f is not exposed to the outside of the case 59. Note that each of the compliance substrates 59e, 59f may be exposed to the outside of the case 59. Each of the compliance substrates 59e, 59f may be provided as needed or may be omitted.

[0050] The wiring board 60 is mounted on the surface of the vibration plate 54 facing the Z2 direction, and is a mounting component for electrically connecting the control unit 20 and the liquid ejection head 50. The wiring board 60 is a flexible wiring board such as a COF (Chip On Film), an FPC (Flexible Printed Circuit), or an FFC (Flexible Flat Cable). A drive circuit 61 for supplying a drive voltage to each piezoelectric element 55 is mounted on the wiring board 60 of this embodiment. The drive circuit 61 is a circuit that switches whether or not to supply at least a portion of the waveform included in the drive signal D as a drive pulse, based on the control signal S.

[0051] 1-3. First pressure chamber, second pressure chamber and third pressure chamber The first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 will be described in detail below with reference to FIGS.

[0052] Fig. 4 is an enlarged cross-sectional view showing a portion of the liquid ejection head 50 according to the first embodiment. Fig. 5 is a cross-sectional view taken along line BB in Fig. 4. Fig. 6 is a cross-sectional view taken along line CC in Fig. 4. Note that Fig. 4 shows a portion of the cross section shown in Fig. 3.

[0053] First, before describing the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3, the piezoelectric element 55 will be described.

[0054] As shown in FIG. 5, each piezoelectric element 55 includes a first electrode 55a, a piezoelectric layer 55b, and a second electrode 55c, which are stacked in this order in the Z2 direction. The first electrodes 55a are individual electrodes spaced apart from one another for each piezoelectric element 55. A drive voltage included in a drive signal D is applied to one of the first electrodes 55a. The drive voltage is a time-varying voltage. The second electrode 55c is a strip-shaped common electrode extending continuously along the Y-axis across the plurality of piezoelectric elements 55. A reference voltage included in the drive signal D is applied to the other electrode. The reference voltage is a constant voltage regardless of time, and may be set to, for example, a value slightly higher than the ground voltage. Alternatively, the first electrode 55a may be used as a common electrode to supply the reference voltage, and the second electrode 55c may be used as an individual electrode to supply the drive voltage. In either case, a voltage equivalent to the difference between the drive voltage and the reference voltage is applied to the piezoelectric layer 55b. Examples of metal materials for these electrodes include platinum (Pt), aluminum (Al), nickel (Ni), gold (Au), and copper (Cu), and among these, one type can be used alone, or two or more types can be combined in the form of an alloy or laminate. The piezoelectric layer 55b is made of a piezoelectric material such as lead zirconate titanate (Pb(Zr,Ti)O3), and is provided individually for each piezoelectric element 55, for example. When the vibration plate 54 vibrates in conjunction with the deformation of the piezoelectric element 55, the pressure in the first pressure chamber C1 and the second pressure chamber C2 fluctuates, and accordingly, the pressure in the third pressure chamber C3 fluctuates, causing ink to be ejected from the nozzle N.

[0055] The above-described piezoelectric element 55 is commonly disposed across the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3, thereby enabling the liquid ejection head 50 to be made smaller in size in the direction along the X axis.

[0056] As shown in FIG. 4, the first pressure chamber substrate 52 has a first portion 52c, a second portion 52d, and a third portion 52e. These portions are spaced apart from one another and are arranged in the X1 direction in the order of the first portion 52c, the third portion 52e, and the second portion 52d. In this manner, the second portion 52d is spaced apart from the first portion 52c. Furthermore, the third portion 52e is spaced apart from the first portion 52c and the second portion 52d, and is located between the first portion 52c and the second portion 52d. Meanwhile, the second pressure chamber substrate 51 has a fourth portion 51e and a fifth portion 51f. These portions are spaced apart from one another and are arranged in the X1 direction in the order of the fourth portion 51e and the fifth portion 51f. In this manner, the fifth portion 51f is spaced apart from the fourth portion 51e.

[0057] In this way, by partitioning the upper portion of the third pressure chamber C3, which communicates with the nozzle N, by the third portion 52e of the first pressure chamber substrate 52, the cross-sectional area of ​​the flow path leading from one of the first pressure chamber C1 and the second pressure chamber C2 to the other via the third pressure chamber C3 can be reduced directly above the nozzle N. In this embodiment, the cross-sectional area of ​​the flow path refers to the cross-sectional area of ​​the flow path directly above the nozzle N when viewed from the X-axis direction, and has widths in the Y-axis direction and the Z-axis direction. In this embodiment, the width in the Z-axis direction can be limited to the thickness Lb of the second pressure chamber substrate 51, thereby reducing the cross-sectional area. As a result, thickened ink can be sufficiently removed. In addition, by forming the first pressure chamber C1 and the second pressure chamber C2 using the first portion 52c and the second portion 52d of the first pressure chamber substrate 52 as partition walls, the pressure generated by the piezoelectric element 55 can be prevented from escaping from the first pressure chamber C1 and the second pressure chamber C2.

[0058] Each of the first portion 52c and the second portion 52d has a shape extending in the Z1 direction with a constant width when viewed in a cross section perpendicular to the Y axis (a cross section extending in the X and Z directions when viewed from the Y axis direction). Therefore, the first portion 52c has a first wall surface 52c1. The first wall surface 52c1 faces the X1 direction, faces the third portion 52e, and extends along the stacking direction. Meanwhile, the second portion 52d has a second wall surface 52d1. The second wall surface 52d1 faces the X2 direction, faces the third portion 52e, and extends along the stacking direction. The provision of the first wall surface 52c1 and the second wall surface 52d1 effectively prevents the pressure generated by the piezoelectric element 55 from escaping from the first pressure chamber C1 and the second pressure chamber C2. In the illustration, the first wall surface 52c1 and the second wall surface 52d1 are both flat surfaces. However, the shapes of the first wall surface 52c1 and the second wall surface 52d1 are not limited to the illustrated example, and may be, for example, curved or bent in a concave or convex shape.

[0059] The fourth portion 51e and the fifth portion 51f each have a shape extending in the Z2 direction with a constant width when viewed in a cross section perpendicular to the Y axis. Therefore, the fourth portion 51e has a surface facing the X1 direction, and the fifth portion 51f has a surface facing the X2 direction, and these surfaces face each other and form the wall surfaces of the third pressure chamber C3. This allows the pressure from the piezoelectric element 55 to be efficiently transmitted from the third pressure chamber C3 to the nozzle N. The shapes of the surfaces of the fourth portion 51e and the fifth portion 51f that form the wall surfaces of the third pressure chamber C3 are not limited to the illustrated example. For example, they may be inclined toward the nozzle N, or may be curved or bent in a concave or convex shape.

[0060] The third portion 52e has a shape whose width decreases in the Z1 direction when viewed in a cross section perpendicular to the Y axis. Therefore, the third portion 52e has a first inclined surface 52e1 and a second inclined surface 52e2. The first inclined surface 52e1 faces the first portion 52c and is inclined toward the X1 direction with respect to the stacking direction. The second inclined surface 52e2 faces the second portion 52d and is inclined toward the X2 direction with respect to the stacking direction. By providing the first inclined surface 52e1 and the second inclined surface 52e2 in this manner, the pressure of the liquid can be efficiently transmitted from both the first pressure chamber C1 and the second pressure chamber C2 to the nozzle N via the third pressure chamber C3. In the illustration, the first inclined surface 52e1 and the second inclined surface 52e2 are both flat surfaces. However, the shapes of the first inclined surface 52e1 and the second inclined surface 52e2 are not limited to the illustrated example and may be, for example, curved or bent in a concave or convex shape. The inclination angles of the first inclined surface 52e1 and the second inclined surface 52e2 are determined according to the length Lc described below, and are not particularly limited, but are preferably between 30° and 60°.

[0061] As described above, it is preferable that the first portion 52c, the second portion 52d, the fourth portion 51e, and the fifth portion 51f each have a wall surface along the Z-axis direction, and the third portion 52e has a wall surface inclined with respect to the Z-axis direction. However, if the above-described effect is not required, the present invention is not limited to this configuration. For example, the first portion 52c, the second portion 52d, the fourth portion 51e, and the fifth portion 51f may have a wall surface inclined with respect to the Z-axis direction instead of a wall surface along the Z-axis direction. Furthermore, for example, the third portion 52e may have a wall surface along the Z-axis instead of a wall surface inclined with respect to the Z-axis direction.

[0062] 5 and 6, the third portion 52e is formed of a continuous member along the Y-axis direction so as to span the multiple pressure chambers C. Furthermore, although not shown in FIGS. 5 and 6, the first portion 52c, the second portion 52d, the fourth portion 51e, and the fifth portion 51f are each also formed of a continuous member along the Y-axis direction so as to span the multiple pressure chambers C.

[0063] 4 to 6, the first pressure chamber C1 is formed by a space inside the first pressure chamber substrate 52, and is partitioned by a first portion 52c and a third portion 52e of the first pressure chamber substrate 52 and a fourth portion 51e of the second pressure chamber substrate 51. In detail, the first pressure chamber C1 has the third portion 52e as a wall surface in the X1 direction, the first portion 52c as a wall surface in the X2 direction, and the fourth portion 51e as a wall surface in the Z1 direction.

[0064] The second pressure chamber C2 is formed by a space inside the first pressure chamber substrate 52, and is defined by a second portion 52d and a third portion 52e of the first pressure chamber substrate 52 and a fifth portion 51f of the second pressure chamber substrate 51. In detail, the second pressure chamber C2 has the second portion 52d as a wall surface in the X1 direction, the third portion 52e as a wall surface in the X2 direction, and the fifth portion 51f as a wall surface in the Z1 direction.

[0065] The third pressure chamber C3 is formed by a space inside the second pressure chamber substrate 51, and is partitioned by a third portion 52e of the first pressure chamber substrate 52 and a fourth portion 51e and a fifth portion 51f of the second pressure chamber substrate 51. In detail, the fifth portion 51f is a wall surface in the X1 direction, the fourth portion 51e is a wall surface in the X2 direction, and the third portion 52e is a wall surface in the Z2 direction.

[0066] 4, the length L3 of the third pressure chamber C3 in the extension direction is preferably shorter than the length L1 of the first pressure chamber C1 in the extension direction and shorter than the length L2 of the second pressure chamber C2 in the extension direction. This allows the liquid pressure to be efficiently transmitted from both the first pressure chamber C1 and the second pressure chamber C2 to the nozzle N via the third pressure chamber C3. Furthermore, by increasing the lengths of the first pressure chamber C1 and the second pressure chamber C2 in the extension direction, the displacement of the piezoelectric element 55 can be increased. If this effect is not required, the length L3 of the third pressure chamber C3 in the extension direction may be longer than the length L1 of the first pressure chamber C1 in the extension direction or may be longer than the length L2 of the second pressure chamber C2 in the extension direction.

[0067] In the present embodiment, the length Lc of the third portion 52e in the extension direction of the lower surface thereof is longer than the length Ld of the third portion 52e in the extension direction of the nozzle N. This makes it possible to reduce the cross-sectional area of ​​the flow path leading from one of the first pressure chamber C1 and the second pressure chamber C2 to the other via the third flow path over the entire area directly above the nozzle N.

[0068] 4, the thickness Lb of the third pressure chamber C3 along the Z axis is equal to the thickness of the first pressure chamber substrate 52. Note that the thickness Lb is not limited to the example shown in the figure, and it is sufficient if it is equal to or greater than the thickness of the first pressure chamber substrate 52 and smaller than the total thickness La of the first pressure chamber substrate 52 and the second pressure chamber substrate 51.

[0069] The distance Le between the first portion 52c and the fourth portion 51e is preferably shorter than the distance between the third portion 52e and the fourth portion 51e. This makes it difficult for the pressure in the first pressure chamber C1 caused by the piezoelectric element 55 to escape to the common discharge flow path 51d. Similarly, the distance Lf between the second portion 52d and the fifth portion 51f is preferably shorter than the distance between the third portion 52e and the fifth portion 51f. This makes it difficult for the pressure in the second pressure chamber C2 caused by the piezoelectric element 55 to escape to the common supply flow path 51c.

[0070] The operation of the liquid ejection head 50 will be explained below in comparison with Comparative Examples 1-3.

[0071] 7 is an enlarged cross-sectional view showing a portion of a liquid ejection head 50X of Comparative Example 1. The liquid ejection head 50X has the same configuration as the liquid ejection head 50, except that it has a substrate 52X instead of the first pressure chamber substrate 52, and a substrate 51X instead of the second pressure chamber substrate 51. The thickness of the substrate 52X is Lb, the same as the first pressure chamber substrate 52. The thickness of the substrate 51X is La-Lb, the same as the second pressure chamber substrate 51.

[0072] The substrate 51X is configured similarly to the second pressure chamber substrate 51, except that it has a portion 51p instead of the fourth portion 51e and the fifth portion 51f. The portion 51p extends in the direction along the X-axis, and the portion 51p, the first portion 52c, and the second portion 52d define a pressure chamber CX. A through-hole that, together with the nozzle substrate 53, defines a nozzle N is provided in the portion 51p.

[0073] The substrate 52X is configured in the same manner as the first pressure chamber substrate 52, except that the third portion 52e is omitted.

[0074] In this liquid ejection head 50X, the circulation flow path of the circulation mechanism 70 is connected between the space in the substrate 51X and the space in the substrate 52X directly above the nozzle N, resulting in a locally large cross-sectional area. In this embodiment, the cross-sectional area of ​​the flow path refers to the cross-sectional area of ​​the flow path directly above the nozzle N when viewed from the X-axis direction, and has widths in the Y-axis direction and the Z-axis direction. That is, since both the space in the substrate 51X and the space in the substrate 52X exist directly above the nozzle N, the width of the flow path directly above the nozzle N in the Z-axis direction is the combined thickness La of the first pressure chamber substrate 52 and the second pressure chamber substrate 51, which is much larger than the flow path directly above the nozzle N in the first embodiment. This results in a locally reduced flow rate, which in turn results in insufficient removal of thickened ink. Additionally, the pressure applied to the piezoelectric element 55 is likely to escape to both sides of the pressure chamber CX in the extension direction in addition to the nozzle N, resulting in insufficient ejection efficiency.

[0075] 8 is an enlarged cross-sectional view showing a portion of a liquid ejection head 50Y of Comparative Example 2. The liquid ejection head 50Y is configured similarly to the liquid ejection head 50, except that the first pressure chamber substrate 52 is replaced with a substrate 52Y, and the second pressure chamber substrate 51 is replaced with a substrate 51Y.

[0076] The substrate 51Y is configured in the same manner as the second pressure chamber substrate 51, except that the fourth portion 51e and the fifth portion 51f are omitted.

[0077] The substrate 52Y is configured in the same manner as the first pressure chamber substrate 52, except that it has a portion 52p instead of the first portion 52c, the second portion 52d, and the third portion 52e. The portion 52p extends in the direction along the X-axis, and a pressure chamber CY is formed between the portion 52p and the nozzle substrate 53.

[0078] As with this liquid ejection head 50Y, it is conceivable to form a pressure chamber CY in the space within the substrate 51Y by leaving a portion 52p of the substrate 52Y directly below the piezoelectric element 55. However, doing so reduces the cross-sectional area directly above the nozzle N, and while this can prevent a decrease in flow rate in the circulation flow path by the circulation mechanism 70, the substrate 52Y covers the area directly below the piezoelectric element 55, and therefore, when the piezoelectric element 55 is driven, the substrate 52Y suppresses vibration of the diaphragm 54, resulting in poor ejection characteristics.

[0079] 9 is an enlarged cross-sectional view showing a portion of a liquid ejection head 50Z of Comparative Example 3. The liquid ejection head 50Z has the same configuration as the liquid ejection head 50, except that it has a substrate 52Z instead of the first pressure chamber substrate 52, and a substrate 51Y instead of the second pressure chamber substrate 51. The substrate 51Y is the same as that of Comparative Example 2.

[0080] The substrate 52Z is ​​configured in the same way as the first pressure chamber substrate 52, except that it has a portion 52q instead of the first portion 52c, the second portion 52d, and the third portion 52e. The portion 52q is provided only partially above the nozzle N, and a pressure chamber CZ is formed that is partitioned by the vibration plate 54, the portion 52q, and the nozzle substrate 53. In other words, the portion 52q corresponds to the portion 52p of Comparative Example 2, whose length in the direction along the X-axis is shortened.

[0081] It is conceivable to provide a portion 52q that is shorter in length in the direction along the X-axis than the portion 52p in this type of liquid ejection head 50Z. In this way, the substrate 52Z is ​​not provided anywhere other than the portion 52q, and therefore, unlike Comparative Example 2, it is possible to vibrate the diaphragm 54 in a suitable manner. However, the pressure chamber CZ is wide open except for the central portion on the left and right sides in the figure, and this does not solve the problem, as in Comparative Example 1, that the pressure when the piezoelectric element 55 is driven tends to escape to the sides of the pressure chamber CZ.

[0082] To solve the problems of Comparative Examples 1-3, the liquid ejection head 50 is provided with three divided pressure chambers: a first pressure chamber C1, a second pressure chamber C2, and a third pressure chamber C3. The third pressure chamber C3 is located in the center in the direction along the X axis and communicates with the nozzle N. Since the upper part of the third pressure chamber C3 is partitioned by the third portion 52e of the first pressure chamber substrate 52, the cross-sectional area directly above the nozzle N can be reduced in the flow path for circulation by the circulation mechanism 70. In addition, the first pressure chamber C1 and the second pressure chamber C2 are formed by partitioning the left and right ends of the range in which the piezoelectric element 55 is present using the first portion 52c and the second portion 52d of the first pressure chamber substrate 52 as partition walls, and therefore pressure leakage to the sides of the pressure chamber C can be suppressed.

[0083] 2. Second embodiment A second embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the first embodiment, the reference numerals used in the description of the first embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0084] 10 is an enlarged cross-sectional view showing a portion of a liquid ejection head 50A according to the second embodiment. The liquid ejection head 50A is configured similarly to the liquid ejection head 50, except that it has a first pressure chamber substrate 52A instead of the first pressure chamber substrate 52. The first pressure chamber substrate 52A is configured similarly to the first pressure chamber substrate 52 of the first embodiment, except that it has a third portion 52f instead of the third portion 52e of the first embodiment.

[0085] In this embodiment, the first pressure chamber C1 is defined by the first portion 52c, the third portion 52f, and the fourth portion 51e. The second pressure chamber C2 is defined by the second portion 52d, the third portion 52f, and the fifth portion 51f. The third pressure chamber C3 is defined by the third portion 52f, the fourth portion 51e, and the fifth portion 51f.

[0086] The third portion 52f has a similar configuration to the third portion 52e of the first embodiment, except for the length Lc. Specifically, the third portion 52f has a shape in which the width decreases in the Z1 direction when viewed in a cross section perpendicular to the Y axis. Therefore, the third portion 52f has a first inclined surface 52f1 and a second inclined surface 52f2. The first inclined surface 52f1 faces the first portion 52c and is inclined with respect to the stacking direction. The second inclined surface 52f2 faces the second portion 52d and is inclined with respect to the stacking direction. By providing the first inclined surface 52f1 and the second inclined surface 52f2 in this manner, the pressure of the liquid can be efficiently transmitted from both the first pressure chamber C1 and the second pressure chamber C2 to the nozzle N via the third pressure chamber C3. In the illustration, the first inclined surface 52f1 and the second inclined surface 52f2 are both flat surfaces. However, the shapes of the first inclined surface 52f1 and the second inclined surface 52f2 are not limited to the illustrated example, and may be, for example, curved or bent in a concave or convex shape. The inclination angles of the first inclined surface 52f1 and the second inclined surface 52f2 are determined according to the length Lc described below, and are not particularly limited, but are preferably between 30° and 60°.

[0087] In the present embodiment, the length Lc of the lower surface of the third portion 52e in the extension direction is shorter than the length of the nozzle N in the extension direction. This allows the liquid pressure to be efficiently transmitted from both the first pressure chamber C1 and the second pressure chamber C2 toward the nozzle N via the third pressure chamber C3.

[0088] According to the second embodiment described above, it is also possible to sufficiently remove thickened ink while maintaining excellent ejection characteristics.

[0089] 3. Third embodiment A third embodiment of the present disclosure will be described below. In the following exemplary embodiments, elements whose actions and functions are similar to those of the first embodiment will be designated by the same reference numerals as those used in the description of the first embodiment, and detailed descriptions thereof will be omitted where appropriate.

[0090] Figure 11 is an enlarged cross-sectional view of a portion of a liquid ejection head 50B according to the third embodiment. Figure 12 is a cross-sectional view taken along line BB in Figure 11. The liquid ejection head 50B is configured similarly to the liquid ejection head 50, except that it has a first pressure chamber substrate 52B instead of the first pressure chamber substrate 52. The first pressure chamber substrate 52B is configured similarly to the first pressure chamber substrate 52 of the first embodiment, except that it has a third portion 52g instead of the third portion 52e of the first embodiment.

[0091] In this embodiment, the first pressure chamber C1 is defined by the first portion 52c, the third portion 52g, and the fourth portion 51e. The second pressure chamber C2 is defined by the second portion 52d, the third portion 52g, and the fifth portion 51f. The third pressure chamber C3 is defined by the third portion 52g, the fourth portion 51e, and the fifth portion 51f.

[0092] As shown in FIG. 11, the third portion 52g has a shape that extends in the Z1 direction with a constant width when viewed in a cross section perpendicular to the Y axis. Therefore, the third portion 52g has a wall surface 52g1 and a wall surface 52g2. The wall surface 52g1 faces the X2 direction, faces the first portion 52c, and extends along the stacking direction. The wall surface 52g2 faces the X1 direction, faces the second portion 52d, and extends along the stacking direction. The shapes of the wall surfaces 52g1 and 52g2 are not limited to the illustrated example. For example, they may be inclined toward the nozzle N or may be curved or bent in a concave or convex shape.

[0093] 12, a space Sa that communicates with the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 is formed in the third portion 52e. This reduces the flow path resistance of the flow path from one of the first pressure chamber C1 and the second pressure chamber C2 to the other pressure chamber via the third flow path. In the illustration, the space Sa extends over the entire area in the thickness direction of the first pressure chamber substrate 52B. Note that the shape of the space Sa is not limited to the example shown in the illustration, and may be, for example, smaller than the thickness of the first pressure chamber substrate 52B.

[0094] According to the third embodiment described above, it is also possible to sufficiently remove thickened ink while maintaining excellent ejection characteristics.

[0095] 4. Fourth embodiment A fourth embodiment of the present disclosure will be described below. In the following exemplary embodiments, elements whose actions and functions are similar to those of the first embodiment will be designated by the same reference numerals as those used in the description of the first embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0096] Figure 13 is an enlarged cross-sectional view showing a portion of a liquid ejection head 50C according to the fourth embodiment. Figure 14 is a cross-sectional view taken along line CC in Figure 13. The liquid ejection head 50C is configured similarly to the liquid ejection head 50, except that it has a first pressure chamber substrate 52C instead of the first pressure chamber substrate 52. The first pressure chamber substrate 52C is configured similarly to the first pressure chamber substrate 52 of the first embodiment, except that it has a third portion 52h instead of the third portion 52e of the first embodiment.

[0097] In this embodiment, the first pressure chamber C1 is defined by the first portion 52c, the third portion 52h, and the fourth portion 51e. The second pressure chamber C2 is defined by the second portion 52d, the third portion 52h, and the fifth portion 51f. The third pressure chamber C3 is defined by the third portion 52h, the fourth portion 51e, and the fifth portion 51f.

[0098] 14, a space Sa that communicates with the first pressure chamber C1, the second pressure chamber C2, and the third pressure chamber C3 is formed in the third portion 52h. This reduces the flow path resistance of the flow path from one of the first pressure chamber C1 and the second pressure chamber C2 to the other pressure chamber via the third pressure chamber C3. In the illustration, the space Sa extends over the entire area in the thickness direction of the first pressure chamber substrate 52B. Note that the shape of the space Sa is not limited to the example shown in the illustration, and may be, for example, smaller than the thickness of the first pressure chamber substrate 52B.

[0099] The third portion 52h has a third inclined surface 52h1 and a fourth inclined surface 52h2. The third inclined surface 52h1 faces the first portion 52c and is inclined relative to the arrangement direction. The fourth inclined surface 52h2 faces the second portion 52d and is inclined relative to the arrangement direction. By providing the third inclined surface 52h1 and the fourth inclined surface 52h2 in this manner, the deformation area of ​​the vibration plate 54 caused by the piezoelectric element 55 can be increased. As a result, the amount of liquid ejected from the nozzle N can be increased. In addition, the flow path resistance of the flow path from one of the first pressure chamber C1 and the second pressure chamber C2 to the other pressure chamber via the third flow path can be reduced. Furthermore, the third inclined surface 52h1 and the fourth inclined surface 52h2 can be formed using a silicon crystal plane.

[0100] 13, the third portion 52h has a shape extending in the Z1 direction with a constant width when viewed in a cross section perpendicular to the Y axis. Therefore, the third inclined surface 52h1 faces the first portion 52c and extends along the stacking direction. The fourth inclined surface 52h2 faces the second portion 52d and extends along the stacking direction. The shapes of the third inclined surface 52h1 and the fourth inclined surface 52h2 when viewed in a cross section perpendicular to the Y axis are not limited to the illustrated example. For example, they may be inclined toward the nozzle N or may have a concave or convex curved or bent shape.

[0101] According to the fourth embodiment described above, it is also possible to sufficiently remove thickened ink while maintaining excellent ejection characteristics.

[0102] 5. Variations The above-described exemplary embodiments can be modified in various ways. Specific modified embodiments that can be applied to the above-described embodiments are exemplified below. Two or more embodiments arbitrarily selected from the following examples can be combined as appropriate to the extent that they are not mutually contradictory.

[0103] 5-1. Variation 1 In the above-described embodiment, a serial type liquid ejection device 100 was exemplified in which a transport body 41 equipped with a liquid ejection head 50 is moved back and forth in the width direction of the medium M, but the liquid ejection device may also be a line type in which multiple nozzles N are distributed across the entire width of the medium M.

[0104] 5-2. Variation 2 The liquid ejection device exemplified in the above-described embodiment can be employed in various devices such as facsimile machines and copiers, in addition to devices dedicated to printing. However, the uses of the liquid ejection device are not limited to printing. For example, a liquid ejection device that ejects a solution of a color material is used as a manufacturing device for forming color filters for display devices such as liquid crystal display panels. Furthermore, a liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board. Furthermore, a liquid ejection device that ejects a solution of an organic substance related to a living organism is used as a manufacturing device for manufacturing biochips, for example. [Explanation of symbols]

[0105] 10...liquid container, 20...controller, 30...transport mechanism, 40...movement mechanism, 41...transport body, 42...transport belt, 50...liquid ejection head, 50A...liquid ejection head, 50B...liquid ejection head, 50C...liquid ejection head, 50X...liquid ejection head, 50Y...liquid ejection head, 50Z...liquid ejection head, 51...second pressure chamber substrate, 51X...substrate, 51Y...substrate, 51a...flow path, 51b...flow path, 51c...common supply flow path, 51d...common discharge flow path, 51e...fourth portion, 51f...fifth portion, 51p...portion, 52...second 1 pressure chamber substrate, 52A...first pressure chamber substrate, 52B...first pressure chamber substrate, 52C...first pressure chamber substrate, 52X...substrate, 52Y...substrate, 52Z...substrate, 52a...flow path, 52b...flow path, 52c...first portion, 52c1...first wall surface, 52d...second portion, 52d1...second wall surface, 52e...third portion, 52e1...first inclined surface, 52e2...second inclined surface, 52f...third portion, 52f1...first inclined surface, 52f2...second inclined surface, 52g...third portion, 52g1...wall surface, 52g2...wall surface, 52h...third portion, 52h1...third inclined surface, 52h2...fourth inclined surface, 52p...portion, 52q...portion, 53...nozzle substrate, 54...diaphragm, 55...piezoelectric element, 55a...first electrode, 55b...piezoelectric layer, 55c...second electrode, 56...first absorption member, 56a...compliance substrate, 56b...weight, 57...second absorption member, 57a...compliance substrate, 57b...weight, 58...sealing plate, 58a...flow path, 58b...flow path, 58c...wiring hole, 59...case, 59a...flow path, 59b...flow path, 59c...inlet, 59d...outlet, 59e...compliance substrate , 59f...compliance board, 60...wiring board, 61...drive circuit, 70...circulation mechanism, 100...liquid ejection device, C...pressure chamber, C1...first pressure chamber, C2...second pressure chamber, C3...third pressure chamber, CX...pressure chamber, CY...pressure chamber, CZ...pressure chamber, D...drive signal, DA...second absorption chamber, DM...conveying direction, La...total thickness, Lb...thickness, Le...distance, Lf...distance, M...medium, N...nozzle, RA...reservoir, RB...reservoir, S...control signal, S1...sealed space, S2...sealed space, S3...sealed space, Sa...space.

Claims

1. a piezoelectric element; a vibration plate that vibrates when driven by the piezoelectric element; a first pressure chamber substrate; a second pressure chamber substrate; a nozzle substrate on which nozzles for ejecting liquid are provided, and a liquid ejection head in which the nozzle substrate and the nozzles are stacked in this order from top to bottom in a stacking direction, the first pressure chamber substrate has a first portion, a second portion spaced apart from the first portion, and a third portion spaced apart from the first portion and the second portion and positioned between the first portion and the second portion, the second pressure chamber substrate has a fourth portion and a fifth portion spaced apart from the fourth portion, The first pressure chamber substrate has: a first pressure chamber formed as a space within the first pressure chamber substrate and partitioned by the first portion, the third portion, and the fourth portion; a second pressure chamber formed as a space within the first pressure chamber substrate and partitioned by the second portion, the third portion, and the fifth portion; The second pressure chamber substrate has: a third pressure chamber is provided, which is constituted by a space within the second pressure chamber substrate and is partitioned by the third portion, the fourth portion, and the fifth portion, and which communicates with the first pressure chamber, the second pressure chamber, and the nozzle; the piezoelectric element is commonly disposed across the first pressure chamber, the second pressure chamber, and the third pressure chamber; A liquid ejection head characterized by:

2. the first pressure chamber, the second pressure chamber, and the third pressure chamber each extend in an extension direction; a plurality of sets of the first pressure chamber, the second pressure chamber, and the third pressure chamber are arranged in an arrangement direction intersecting the extension direction; 2. The liquid ejection head according to claim 1.

3. a common supply flow path for commonly supplying liquid to the plurality of sets; and a common discharge flow path that discharges liquid from the plurality of sets in common.

3. The liquid ejection head according to claim 2.

4. a length of the third pressure chamber in the extension direction is shorter than a length of the first pressure chamber in the extension direction and is also shorter than a length of the second pressure chamber in the extension direction; 4. The liquid ejection head according to claim 2 or 3.

5. a length of a lower surface of the third portion in the extension direction is longer than a length of the nozzle in the extension direction; 4. The liquid ejection head according to claim 2 or 3.

6. a length of a lower surface of the third portion in the extension direction is shorter than a length of the nozzle in the extension direction; 4. The liquid ejection head according to claim 2 or 3.

7. The third portion is a first inclined surface facing the first portion and inclined with respect to the stacking direction; a second inclined surface facing the second portion and inclined with respect to the stacking direction; 4. The liquid ejection head according to claim 2 or 3.

8. the first portion faces the third portion and has a first wall surface along the stacking direction; the second portion faces the third portion and has a second wall surface along the stacking direction; 8. The liquid ejection head according to claim 7.

9. The third portion is a third inclined surface facing the first portion and inclined with respect to the arrangement direction; a fourth inclined surface facing the second portion and inclined with respect to the arrangement direction, 4. The liquid ejection head according to claim 2 or 3.

10. a space communicating with the first pressure chamber, the second pressure chamber, and the third pressure chamber is formed in the third portion; 4. The liquid ejection head according to claim 2 or 3.

11. a first absorption chamber communicating with the first pressure chamber for absorbing pressure generated by the piezoelectric element; a second absorption chamber communicating with the second pressure chamber for absorbing pressure generated by the piezoelectric element; 3. The liquid ejection head according to claim 2.

12. a first absorption member formed of the same material as the vibration plate and at least a part of the piezoelectric element is provided above the first absorption chamber; a second absorption member formed of the same material as the vibration plate and at least a part of the piezoelectric element is provided above the second absorption chamber; 12. The liquid ejection head according to claim 11.

13. the first absorption chamber is formed by a space in the first pressure chamber substrate and a space in the second pressure chamber substrate, the second absorption chamber is formed by a space in the first pressure chamber substrate and a space in the second pressure chamber substrate; 13. The liquid ejection head according to claim 11 or 12.

14. The liquid ejection head according to claim 2 or 3; a control unit for controlling a discharge operation from the liquid discharge head, A liquid ejection device characterized by:

Images