Liquid ejection head and liquid ejection apparatus

Abstract

To provide a technology which eases buffering and accumulation of liquid flow caused by a collision of liquids in a passage to reduce or prevent deterioration of liquid discharge performance in a liquid discharge head.SOLUTION: A liquid discharge head includes: a first pressure chamber extending along a first direction; a second pressure chamber extending along the first direction; a first communication passage connected to the first pressure chamber and extending along the first direction; a second communication passage connected to the second pressure chamber and extending along the first direction; a third communication passage connected to the first communication passage and extending along a second direction intersecting with the first direction; a fourth communication passage connected to the second communication passage and extending along the second direction; a fifth communication passage connected to the third communication passage and the fourth communication passage and extending along the first direction; and a nozzle provided at the fifth communication passage.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection device.

Background Art

[0002] A liquid ejection head including a pressure chamber, a piezoelectric element that applies pressure to the liquid in the pressure chamber, a nozzle that ejects the liquid, and a flow path that connects the pressure chamber and the nozzle is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the flow path connecting the pressure chamber and the nozzle, for example, if buffering between flowing liquids or liquid retention occurs, the liquid ejection performance from the nozzle may not be sufficiently obtained.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] According to a first aspect of the present disclosure, a liquid ejection head is provided. The liquid ejection head includes a first pressure chamber extending along a first direction, a second pressure chamber extending along the first direction, a first communication passage connected to the first pressure chamber and extending along the first direction, a second communication passage connected to the second pressure chamber and extending along the first direction, a third communication passage connected to the first communication passage and extending along a second direction intersecting the first direction, a fourth communication passage connected to the second communication passage and extending along the second direction, a fifth communication passage connected to the third communication passage and the fourth communication passage and extending along the first direction, and a nozzle provided in the fifth communication passage.

[0007] According to a second aspect of the present disclosure, a liquid ejection device is provided. The liquid ejection device includes the liquid ejection head according to the first aspect and a control device that controls a liquid ejection operation from the liquid ejection head. BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0009] A. First Embodiment: FIG. 1 is an explanatory diagram showing an example of a liquid ejection device 100 according to the first embodiment. The liquid ejection device 100 of the first embodiment is, for example, an inkjet printing device that ejects ink, which is an example of a liquid, onto a medium PP such as printing paper. As the medium PP, any printing target such as a resin film or a fabric may be used in addition to printing paper. X, Y, and Z shown in FIG. 1 and each subsequent figure represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are also referred to as the X-axis direction, the Y-axis direction, and the Z-axis direction. The X-axis direction is an example of the first direction, and the Z-axis direction is an example of the second direction. When specifying a direction, the positive direction is denoted as "+", the negative direction is denoted as "-", and positive and negative signs are used together in the direction notation. The direction in which the arrow in each figure points is described as the + direction, and the opposite direction is described as the - direction. In this embodiment, an example where the Z direction coincides with the vertical direction is shown, and an example where the +Z direction is vertically downward and the -Z direction is vertically upward is shown. Further, when the positive and negative directions are not limited, the three X, Y, and Z are described as the X-axis, the Y-axis, and the Z-axis. Note that the first direction and the second direction may not be orthogonal to each other and may intersect at any internal angle.

[0010] As shown in FIG. 1, the liquid ejection device 100 includes a plurality of liquid ejection heads 1 that eject liquid, a control device 90, a movement mechanism 91, a conveyance mechanism 92, a liquid container 93, and a circulation mechanism 94. The control device 90 is a microcomputer including, for example, a microprocessor such as a CPU or an FPGA, and a storage circuit such as a semiconductor memory. The control device 90 controls the operations of each part of the liquid ejection device 100 by executing a program stored in advance in the storage circuit. The control device 90 can control, for example, the ink ejection operation from the liquid ejection head 1. Specifically, a signal for controlling the ejection of ink and the like is supplied from the control device 90 to the liquid ejection head 1. The liquid ejection head 1 ejects the ink supplied from the liquid container 93 in an amount and at a timing according to the signal supplied from the control device 90.

[0011] The liquid container 93 stores ink. As the ink, for example, in addition to ink in which pigments as coloring materials are dispersed in a solvent, ink containing dyes or ink containing both pigments and dyes as coloring materials can be used. The ink may include general aqueous ink, oil-based ink, and various liquid compositions such as gel ink and hot melt ink. As the liquid container 93, for example, a cartridge detachable from the liquid ejection device 100, a bag-shaped ink pack formed of a flexible film, or an ink tank capable of replenishing ink can be adopted.

[0012] The circulation mechanism 94 is a pump for supplying the liquid stored in the liquid container 93 to the liquid ejection head 1 under the control of the control device 90. The circulation mechanism 94 collects the ink stored in the liquid ejection head 1 and returns the collected ink to the liquid ejection head 1.

[0013] The moving mechanism 91 conveys the medium PP in the +Y direction under the control of the control device 90. The conveying mechanism 92 includes a storage case 921 that houses a plurality of liquid ejection heads 1 and an endless belt 922 to which the storage case 921 is fixed. The conveying mechanism 92 reciprocates the liquid ejection head 1 along the X-axis direction by operating the endless belt 922 to which the storage case 921 is fixed under the control of the control device 90. The conveying direction of the medium PP and the moving direction of the liquid ejection head 1 are not limited to being orthogonal, and may intersect at a predetermined angle. The liquid container 93 and the circulation mechanism 94 may be housed in the storage case 921 together with the liquid ejection head 1.

[0014] As shown in FIG. 1, the control device 90 outputs a drive signal Com for driving the liquid ejection head 1 and a control signal SI for controlling the liquid ejection head 1 to the liquid ejection head 1. The liquid ejection head 1 is driven by the drive signal Com under the control of the control signal SI to eject ink from some or all of a plurality of nozzles provided in the liquid ejection head 1. In the present embodiment, the ejection direction of the ink is the +Z direction. The liquid ejection head 1 ejects ink from the nozzles while interlocking the conveyance of the medium PP by the movement mechanism 91 and the reciprocating movement of the liquid ejection head 1 by the conveyance mechanism 92, and lands the ink on the surface of the medium PP. As a result, a desired image is formed on the surface of the medium PP. The ejection direction of the ink is not limited to the +Z direction and may be any direction intersecting the X-Y plane.

[0015] The configuration of the liquid ejection head 1 will be described with reference to FIGS. 2 to 5. FIG. 2 is an exploded perspective view of the liquid ejection head 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. In FIG. 3, for ease of understanding of the technology, the boundaries between the respective flow paths are schematically shown using broken lines. FIG. 4 is an explanatory view schematically showing the ink flow path in the liquid ejection head 1 in a plan view. FIG. 5 is an enlarged cross-sectional view of the vicinity of the piezoelectric element PZq. As shown in FIG. 2, the liquid ejection head 1 includes a nozzle substrate 60, a communication plate 2, a pressure chamber substrate 3, a diaphragm 4, a reservoir formation substrate 5, a wiring substrate 8, a compliance sheet 61, and a compliance sheet 62.

[0016] As shown in FIG. 2, the nozzle substrate 60 is an elongated plate-shaped member along the Y-axis direction. The nozzle substrate 60 is manufactured, for example, by processing a single-crystalline silicon substrate using semiconductor manufacturing techniques such as etching. M nozzles Nz are formed on the nozzle substrate 60. M is a natural number of 1 or more. The nozzle Nz is a through-hole provided in the nozzle substrate 60. In the present embodiment, on the nozzle substrate 60, the M nozzles Nz are linearly arranged so as to form a nozzle row Ln extending in the Y-axis direction. The material of the nozzle substrate 60 is not limited to a silicon substrate, and for example, a glass substrate, an SOI substrate, various ceramic substrates, and a metal substrate can be used. Examples of the metal substrate include a stainless steel substrate. As the material of the nozzle substrate 60, an organic substance such as a polyimide resin can also be used. However, it is preferable to use a material having substantially the same coefficient of thermal expansion as that of the communication plate 2 for the nozzle substrate 60. Thereby, when the temperatures of the nozzle substrate 60 and the communication plate 2 change, warping of the nozzle substrate 60 and the communication plate 2 due to the difference in the coefficient of thermal expansion can be suppressed. The surface on the -Z direction side of the nozzle substrate 60, which is one surface of the nozzle substrate 60, is also referred to as the "upper surface TN". As shown in FIG. 3, the communication plate 2 is provided on the upper surface TN of the nozzle substrate 60.

[0017] As shown in FIG. 2, the communication plate 2 is an elongated plate-shaped member along the Y-axis direction. The communication plate 2 is manufactured, for example, by processing a single-crystalline silicon substrate using semiconductor manufacturing techniques. The communication plate 2 is not limited to a silicon substrate, and for example, a flat plate member using a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate, etc. can be used. Examples of the metal substrate include a stainless steel substrate. It is preferable to use a material having substantially the same coefficient of thermal expansion as that of the pressure chamber substrate 3 for the communication plate 2. Thereby, when the temperatures of the pressure chamber substrate 3 and the communication plate 2 change, warping of the pressure chamber substrate 3 and the communication plate 2 due to the difference in the coefficient of thermal expansion can be suppressed. In the present embodiment, an example in which there is one communication plate 2 is shown, but the communication plate 2 is not limited to one and may be a plurality of plates. One surface of the communication plate 2, specifically, the surface on the -Z direction side is also referred to as the "upper surface TR", and the other surface of the communication plate 2, specifically, the surface on the +Z direction side is also referred to as the "lower surface BR".

[0018] As shown in FIGS. 2 and 3, an ink flow path is formed in the communication plate 2. The flow path formed in the communication plate 2 can be formed, for example, by etching the communication plate 2. As shown in FIG. 2, in the communication plate 2, one common supply flow path RA1 extending in the Y-axis direction and one common discharge flow path RA2 extending in the Y-axis direction are formed. Further, in the communication plate 2, as shown in FIGS. 2 and 3, M fifth communication paths RR5 corresponding to each of the M nozzles Nz, M communication flow paths RX1, M communication flow paths RK1, M first communication paths RR1, M third communication paths RR3, M fourth communication paths RR4, M second communication paths RR2, M communication flow paths RK2, and M communication flow paths RX2 are formed. In the present disclosure, the flow path constituted by the communication flow path RX1, the communication flow path RK1, the first communication path RR1, the third communication path RR3, the fifth communication path RR5, the fourth communication path RR4, the second communication path RR2, the communication flow path RK2, and the communication flow path RX2 is also referred to as an "individual flow path". M individual flow paths are formed between one common supply flow path RA1 and one common discharge flow path RA2 in the communication plate 2. Note that one communication flow path RX1 commonly provided for the M nozzles Nz may be formed in the communication plate 2, or one communication flow path RX2 commonly provided for the M nozzles Nz may be formed.

[0019] As shown in FIG. 3, one end of the communication flow path RX1 is connected to the common supply flow path RA1. The communication flow path RX1 is provided so as to extend from the common supply flow path RA1 in the -X direction along the X-axis direction. One end of the communication flow path RK1 is connected to the other end of the communication flow path RX1. The communication flow path RK1 is provided so as to extend from the communication flow path RX1 in the -Z direction along the Z-axis direction. The other end of the communication flow path RK1 is connected to one end of the first pressure chamber CB1. One end of the first communication path RR1 is connected to the other end of the first pressure chamber CB1.

[0020] The first communication path RR1 is provided so as to extend along the X-axis direction on the upper surface TR of the communication plate 2. The first communication path RR1 is a flow path defined by a groove formed on the upper surface TR of the communication plate 2 by etching the communication plate 2 and the lower surface BC of the pressure chamber substrate 3. Among the grooves formed on the upper surface TR of the communication plate 2, the groove corresponding to the first communication path RR1 is also referred to as the "first communication plate groove portion". The first communication path RR1 is formed by the first communication plate groove portion being blocked by the lower surface BC of the pressure chamber substrate 3. One end of the third communication path RR3 is connected to the other end of the first communication path RR1.

[0021] The third communication path RR3 is a through hole that penetrates the communication plate 2 along the Z-axis direction. The third communication path RR3 is provided so as to extend in the +Z direction along the Z-axis direction from the upper surface TR of the communication plate 2. The other end of the third communication path RR3 is connected to one end of the fifth communication path RR5.

[0022] One nozzle Nz is provided in the fifth communication path RR5. The fifth communication path RR5 is provided so as to extend along the X-axis direction on the lower surface BR of the communication plate 2. The fifth communication path RR5 is a flow path defined by a groove formed on the lower surface BR of the communication plate 2 by etching the communication plate 2 and the upper surface TN of the nozzle substrate 60. Among the grooves formed on the lower surface BR of the communication plate 2, the groove corresponding to the fifth communication path RR5 is also referred to as the "third communication plate groove portion". The fifth communication path RR5 is formed by the third communication plate groove portion being blocked by the upper surface TN of the nozzle substrate 60. One end of the fourth communication path RR4 is connected to the other end of the fifth communication path RR5.

[0023] In this embodiment, the fifth communication path RR5, the first communication path RR1, and the second communication path RR2 are formed in the same wet etching process. This simplifies the manufacturing process and reduces costs. Further, in this embodiment, an etching mask is disposed at the formation position of the fifth communication path RR5, and isotropic wet etching is performed, so that the timing at which the formation position of the fifth communication path RR5 is etched is relatively delayed with respect to the timing at which the first communication path RR1 and the second communication path RR2 are etched. That is, the etching rate for the fifth communication path RR5 is made lower than the etching rates for the first communication path RR1 and the second communication path RR2. Thereby, the depth D5 of the fifth communication path RR5 can be made shallower than the depths D1 and D2 of the first communication path RR1 and the second communication path RR2. Note that the depth D5 of the fifth communication path RR5 may be made equal to the depths D1 and D2 of the first communication path PR1 and the second communication path RR2. In this case, the wet etching processes for the fifth communication path RR5, the first communication path RR1, and the second communication path RR2 may be started at the same timing without disposing an etching mask.

[0024] The fourth communication path RR4 is a through hole that penetrates the communication plate 2 along the Z-axis direction. The fourth communication path RR4 is provided so as to extend in the -Z direction along the Z-axis direction from the lower surface BR of the communication plate 2. The other end of the fourth communication path RR4 is connected to one end of the second communication path RR2.

[0025] The second communication path RR2 is provided so as to extend along the X-axis direction on the upper surface TR of the communication plate 2. The second communication path RR2 is a flow path defined by a groove formed on the upper surface TR of the communication plate 2 by etching the communication plate 2 and the lower surface BC of the pressure chamber substrate 3. Of the grooves formed on the upper surface TR of the communication plate 2, the groove corresponding to the second communication path RR2 is also referred to as a "second communication plate groove portion". The second communication path RR2 is formed by the second communication plate groove portion being blocked by the lower surface BC of the pressure chamber substrate 3. One end of the second pressure chamber CB2 is connected to the other end of the second communication path RR2.

[0026] At the other end of the second pressure chamber CB2, a communication flow path RK2 is connected. The communication flow path RK2 is provided so as to extend in the +Z direction along the Z-axis direction from the second pressure chamber CB2. One end of a communication flow path RX2 is connected to the communication flow path RK2. The communication flow path RX2 is provided so as to extend in the -X direction from the communication flow path RK2 along the X-axis direction. The other end of the communication flow path RX2 is connected to a common discharge flow path RA2.

[0027] As shown in FIGS. 2 and 3, compliance sheets 61 and 62 are provided on both sides in the width direction of the lower surface BR of the communication plate 2. The compliance sheet 61 closes the common supply flow path RA1, the communication flow path RX1, and the communication flow path RK1. For example, an elastic material is used as the compliance sheet 61. The compliance sheet 61 absorbs pressure fluctuations of the ink in the common supply flow path RA1, the communication flow path RX1, and the communication flow path RK1. The compliance sheet 62 closes the common discharge flow path RA2, the communication flow path RX2, and the communication flow path RK2. The compliance sheet 62 is, for example, an elastic material and absorbs pressure fluctuations of the ink in the common discharge flow path RA2, the communication flow path RX2, and the communication flow path RK2.

[0028] As shown in FIGS. 2 and 3, a storage chamber forming substrate 5 is provided on the upper surface TR of the communication plate 2. The storage chamber forming substrate 5 is a member that is long in the Y-axis direction as shown in FIG. 2. The storage chamber forming substrate 5 is formed, for example, by injection molding using a resin material. An ink flow path is formed inside the storage chamber forming substrate 5. Specifically, as shown in FIG. 3, one common supply flow path RB1 and one common discharge flow path RB2 are formed in the storage chamber forming substrate 5. The common supply flow path RB1 communicates with the common supply flow path RA1, and the common discharge flow path RB2 communicates with the common discharge flow path RA2.

[0029] The ink storage chamber forming substrate 5 is further provided with an inlet 51 communicating with the common supply channel RB1 and an outlet 52 communicating with the common discharge channel RB2. Ink supplied from the liquid container 93 is introduced into the common supply channel RB1 through the inlet 51. Further, the ink flowing into the common discharge channel RB2 is recovered into the liquid container 93 through the outlet 52.

[0030] As shown in FIG. 2, the ink storage chamber forming substrate 5 is provided with an opening 50. In the opening 50, the pressure chamber substrate 3, the diaphragm 4, and the wiring substrate 8 are arranged. A protective member for protecting the first piezoelectric element PZ1 and the second piezoelectric element PZ2 may be provided in the opening 50.

[0031] As shown in FIG. 2, the pressure chamber substrate 3 is a plate-like member elongated in the Y-axis direction. As shown in FIG. 3, the pressure chamber substrate 3 is provided on the upper surface TR of the communication plate 2. The pressure chamber substrate 3 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology. Ink channels are formed in the pressure chamber substrate 3. Specifically, M first pressure chambers CB1 and M second pressure chambers CB2 corresponding to each of the M nozzles Nz are formed in the pressure chamber substrate 3. The pressure chamber substrate 3 is not limited to a silicon substrate, and may be formed using, for example, a glass substrate, an SOI substrate, various ceramic substrates, etc. The surface on the +Z direction side of the pressure chamber substrate 3, which is one surface of the pressure chamber substrate 3, is also referred to as the "lower surface BC", and the surface on the -Z direction side of the pressure chamber substrate 3, which is the other surface of the pressure chamber substrate 3, is also referred to as the "upper surface TC".

[0032] The first pressure chamber CB1 is provided to extend in the X-axis direction such that the communication channel RK1 and the first communication channel RR1 communicate with each other. The second pressure chamber CB2 is provided to extend in the X-axis direction such that the communication channel RK2 and the second communication channel RR2 communicate with each other. In the following description, when the first pressure chamber CB1 and the second pressure chamber CB2 are not distinguished, they are also referred to as the pressure chamber CBq.

[0033] As shown in FIG. 2, the diaphragm 4 is a plate-shaped member elongated in the Y-axis direction. As shown in FIG. 3, the diaphragm 4 is provided on the upper surface TC of the pressure chamber substrate 3. The diaphragm 4 is an elastically vibratable member that applies pressure to the liquid in the pressure chamber CBq. The diaphragm 4 can be formed, for example, by an elastic film made of silicon oxide provided on the pressure chamber substrate 3 side and an insulator film made of a zirconium oxide film provided on the elastic film. On the upper surface of the diaphragm 4, M first piezoelectric elements PZ1 corresponding to each of the M first pressure chambers CB1 and M second piezoelectric elements PZ2 corresponding to each of the M second pressure chambers CB2 are provided. In the following description, when the first piezoelectric element PZ1 and the second piezoelectric element PZ2 are not distinguished, they are also referred to as piezoelectric elements PZq. The piezoelectric element PZq is an energy conversion element that converts the electrical energy of the drive signal Com into kinetic energy. In the present embodiment, the piezoelectric element PZq is a passive element that deforms in response to a potential change in the drive signal Com.

[0034] The wiring substrate 8 is mounted between the first piezoelectric element PZ1 and the second piezoelectric element PZ2 on the -Z direction side of the diaphragm 4. The wiring substrate 8 is a component for electrically connecting the control device 90 and the liquid ejection head 1, and supplies power to the first piezoelectric element PZ1 and the second piezoelectric element PZ2. As the wiring substrate 8, for example, a flexible wiring substrate such as an FPC or an FFC is used. A drive circuit 81 is mounted on the wiring substrate 8. The drive circuit 81 switches whether to supply the drive signal Com to the piezoelectric element PZq based on the control signal SI.

[0035] As shown in FIG. 5, the piezoelectric element PZq is a laminate in which a piezoelectric body ZMq is interposed between a lower electrode ZDq and an upper electrode ZUq. A pressure chamber CBq is provided on the +Z direction side of the piezoelectric element PZq. A predetermined reference potential is supplied to the lower electrode ZDq. The drive circuit 81 supplies a drive signal Com to the upper electrode ZUq via a wiring 810. The drive signal Com supplied to the first piezoelectric element PZ1 is also called a drive signal Com1, and the drive signal Com supplied to the second piezoelectric element PZ2 is also called a drive signal Com2. In the present embodiment, when ejecting ink from the nozzle Nz, the waveform of the drive signal Com1 supplied by the drive circuit 81 to the first piezoelectric element PZ1 corresponding to the nozzle Nz and the waveform of the drive signal Com2 supplied by the drive circuit 81 to the second piezoelectric element PZ2 corresponding to the nozzle Nz are substantially the same as each other.

[0036] The piezoelectric element PZq deforms in response to a potential change in the drive signal Com. The diaphragm 4 vibrates in conjunction with the deformation of the piezoelectric element PZq. Due to the vibration of the diaphragm 4, the pressure in the pressure chamber CBq fluctuates. When the pressure in the pressure chamber CBq fluctuates, the ink filled inside the pressure chamber CBq is ejected from the nozzle Nz via the first communication path RR1, the second communication path RR2, the third communication path RR3, the fourth communication path RR4, and the fifth communication path RR5. Specifically, when the first piezoelectric element PZ1 is driven by the drive signal Com1, a part of the ink filled inside the first pressure chamber CB1 is ejected from the nozzle Nz via the first communication path RR1, the third communication path RR3, and the fifth communication path RR5. When the second piezoelectric element PZ2 is driven by the drive signal Com2, a part of the ink filled inside the second pressure chamber CB2 is ejected from the nozzle Nz via the second communication path RR2, the fourth communication path RR4, and the fifth communication path RR5.

[0037] As shown in FIG. 3, the ink introduced from the liquid container 93 into the introduction port 51 by the circulation mechanism 94 flows into the common supply channel RA1 via the common supply channel RB1. A part of the ink flowing into the common supply channel RA1 is diverted to the communication channels RX1 of the respective individual channels. The ink flowing into the communication channel RX1 flows into the first pressure chamber CB1 via the communication channel RK1. A part of the ink flowing into the first pressure chamber CB1 flows into the second pressure chamber CB2 via the first communication channel RR1, the third communication channel RR3, the fifth communication channel RR5, the fourth communication channel RR4, and the second communication channel RR2 in this order. A part of the ink flowing into the second pressure chamber CB2 merges at the common discharge channel RA2 after passing through the communication channel RK2 and the communication channel RX2 in this order. The ink flowing into the common discharge channel RA2 is discharged from the discharge port 52 via the common discharge channel RB2. As shown in FIG. 4, the ink flow path from the common supply channel RA1 to the common discharge channel RA2 is also referred to as the "circulation flow path RJ". Specifically, the circulation flow path RJ includes the common supply channel RA1, the individual channels, and the common discharge channel RA2.

[0038] The liquid ejection device 100 of the present embodiment circulates the ink from the common supply channel RA1 to the common discharge channel RA2 via the circulation flow path RJ. Therefore, even when there is a period during which the ink inside the pressure chamber CBq is not ejected from the nozzle Nz, it is possible to reduce or prevent the ink from staying inside the nozzle Nz. Therefore, in the liquid ejection device 100 of the present embodiment, even if the ink inside the pressure chamber CBq is not ejected from the nozzle Nz and the ink thickens inside the nozzle Nz due to evaporation of the liquid component of the ink from the nozzle Nz or the like, the thickened ink can be discharged from inside the nozzle Nz to the common discharge channel RA2 side by the circulation of the ink. Thereby, it is possible to reduce or prevent the occurrence of ejection abnormalities in which ink cannot be ejected from the nozzle Nz due to the thickened ink staying in the nozzle Nz, and it is possible to reduce or prevent the deterioration of the ink ejection performance.

[0039] The liquid ejection device 100 of the present embodiment ejects the ink filled inside the first pressure chamber CB1 and the ink filled inside the second pressure chamber CB2 from one nozzle Nz. Therefore, the liquid ejection device 100 can increase the ejection amount of the ink from the nozzle Nz as compared with, for example, a mode in which only the ink filled inside one pressure chamber CBq is ejected from the nozzle Nz.

[0040] Using FIG. 6, the details of the flow path design in the vicinity of the nozzle Nz of the liquid ejection head 1 will be described. FIG. 6 is an explanatory diagram showing an enlarged cross section of the flow path in the vicinity of the nozzle Nz of the liquid ejection head 1. The cross-sectional view shown in FIG. 6 corresponds to an enlarged view of the vicinity of the nozzle Nz in FIG. 3. In FIG. 6, for ease of understanding of the technology, the boundaries between the respective flow paths are schematically shown by broken lines. In the present disclosure, the length of the flow path in the X-axis direction is also referred to as "width", and the length of the flow path in the Z-axis direction is also referred to as "depth".

[0041] As shown in FIG. 6, the width L1 of the first communication path RR1 is designed to be shorter than the width LP1 of the first pressure chamber CB1. In the present embodiment, the width L1 of the first communication path RR1 is set to 3 / 5 of the width LP1 of the first pressure chamber CB1. The width L1 of the first communication path RR1 is not limited to 3 / 5, and may be set to an arbitrary ratio width such as 2 / 3, 1 / 3, 1 / 4, 3 / 4, 4 / 5, 2 / 5, 1 / 5 of the width LP1 of the first pressure chamber CB1. Further, the form in which the width L1 of the first communication path RR1 is shorter than the width LP1 of the first pressure chamber CB1 is not limited, and the width L1 may be set to a width equal to or greater than the width LP1.

[0042] The width L2 of the second communication path RR2 is designed to be shorter than the width LP2 of the second pressure chamber CB2. In the present embodiment, the width L2 of the second communication path RR2 is set to 3 / 5 of the width LP2 of the second pressure chamber CB2. The width L2 of the second communication path RR2 is not limited to 3 / 5, and may be set to an arbitrary ratio width such as 2 / 3, 1 / 3, 1 / 4, 3 / 4, 4 / 5, 2 / 5, 1 / 5 of the width LP2 of the second pressure chamber CB2. Further, the form in which the width L2 of the second communication path RR2 is shorter than the width LP2 of the second pressure chamber CB2 is not limited, and the width L2 may be set to a width equal to or greater than the width LP2.

[0043] In this embodiment, the width L5 of the fifth connecting passage RR5 is designed to be shorter than the width L1 of the first connecting passage RR1 and shorter than the width L2 of the second connecting passage RR2. Therefore, in this embodiment, the width L5 of the fifth connecting passage RR5 is shorter than the sum of the width L1 of the first connecting passage RR1 and the width L2 of the second connecting passage RR2. Note that the width L5 may be designed to be shorter only with respect to either the width L1 or the width L2. In this case, it is preferable that the width L5 is shorter than the sum of the width L1 and the width L2. However, this is not the limit, and the width L5 can be, for example, longer than the sum of the width L1 and the width L2.

[0044] The width L5 of the fifth connecting passage RR5 is set to be 2 / 3 of the width L1 of the first connecting passage RR1. The width L5 of the fifth connecting passage RR5 is not limited to 2 / 3, and may be set to any ratio width such as 1 / 3, 1 / 4, 3 / 4, 4 / 5, 3 / 5, 2 / 5, 1 / 5 of the width L1 of the first connecting passage RR1. Further, the form in which the width L5 of the fifth connecting passage RR5 is shorter than the width L1 of the first connecting passage RR1 is not the only limit. For example, when the distance from the first pressure chamber CB1 to the nozzle Nz is short and the width L1 is relatively short, the width L5 may be set to be equal to or greater than the width L1.

[0045] The width L5 of the fifth connecting passage RR5 is set to be 2 / 3 of the width L2 of the second connecting passage RR2. The width L5 of the fifth connecting passage RR5 is not limited to 2 / 3, and may be set to any ratio width such as 1 / 3, 1 / 4, 3 / 4, 4 / 5, 3 / 5, 2 / 5, 1 / 5 of the width L2 of the second connecting passage RR2. Further, the form in which the width L5 of the fifth connecting passage RR5 is shorter than the width L2 of the second connecting passage RR2 is not the only limit. For example, when the distance from the second pressure chamber CB2 to the nozzle Nz is short and the width L2 is relatively short, the width L5 may be set to be equal to or greater than the width L2.

[0046] In this embodiment, further, the width L5 of the fifth communication passage RR5 is designed to be shorter than the width LP1 of the first pressure chamber CB1 and shorter than the width LP2 of the second pressure chamber CB2. Therefore, in this embodiment, the width L5 of the fifth communication passage RR5 is shorter than the sum of the width LP1 of the first pressure chamber CB1 and the width LP2 of the second pressure chamber CB2. However, the width L5 may be designed to be shorter only with respect to either the width LP1 or the width LP2. In this case, it is preferable that the width L5 is shorter than the sum of the width LP1 and the width LP2. However, this is not the limit, and the width L5 can be, for example, longer than the sum of the width LP1 and the width LP2.

[0047] In this embodiment, the width L5 is designed to be shorter than the sum of the width L1, the width L2, the width LP1, and the width LP2. However, this is not the limit, and the width L5 can be, for example, longer than the sum of the width L1 and the width L2.

[0048] The width L5 of the fifth communication passage RR5 is set to be 2 / 5 of the width LP1 of the first pressure chamber CB1. The width L5 of the fifth communication passage RR5 is not limited to 2 / 5, and may be set to any ratio width such as 2 / 3, 1 / 3, 1 / 4, 3 / 4, 4 / 5, 3 / 5, 1 / 5 of the width LP1 of the first pressure chamber CB1. Further, the form in which the width L5 of the fifth communication passage RR5 is shorter than the width LP1 of the first pressure chamber CB1 is not the only limit. For example, when the width LP1 is relatively short, the width L5 may be set to be equal to or greater than the width LP1.

[0049] The width L5 of the fifth communication passage RR5 is set to be 2 / 5 of the width LP2 of the second pressure chamber CB2. The width L5 of the fifth communication passage RR5 is not limited to 2 / 5, and may be set to any ratio width such as 2 / 3, 1 / 3, 1 / 4, 3 / 4, 4 / 5, 3 / 5, 1 / 5 of the width LP2 of the second pressure chamber CB2. Further, the form in which the width L5 of the fifth communication passage RR5 is shorter than the width LP2 of the second pressure chamber CB2 is not the only limit. For example, when the width LP2 is relatively short, the width L5 may be set to be equal to or greater than the width LP2.

[0050] As shown in FIG. 6, in the present embodiment, the ink flow paths in the liquid ejection head 1, specifically, the first pressure chamber CB1 and the second pressure chamber CB2, and the ink flow paths formed in the communication plate 2 have a line-symmetric structure with the Z-axis including the nozzle Nz as the axis of symmetry. That is, the width L1 of the first communication path RR1 is set to be substantially the same as the width L2 of the second communication path RR2. Further, in the present embodiment, the width LP1 of the first pressure chamber CB1 and the width LP2 of the second pressure chamber CB2 are substantially the same as each other, and the width L1 of the first communication path RR1 and the width L2 of the second communication path RR2 are substantially the same as each other. However, the ink flow paths in the liquid ejection head 1 are not limited to the line-symmetric structure and may be non-line-symmetric. For example, the width LP1 of the first pressure chamber CB1 and the width LP2 of the second pressure chamber CB2 may be different from each other, and the width L1 of the first communication path RR1 and the width L2 of the second communication path RR2 may be different from each other.

[0051] FIG. 6 schematically shows the thickness T2 of the communication plate 2 and the thickness T3 of the pressure chamber substrate 3. The depths D3 of the third communication path RR3 and the fourth communication path RR4 as the through holes of the communication plate 2 coincide with the thickness T2 of the communication plate 2. The depths DP1 of the first pressure chamber CB1 and the depths DP2 of the second pressure chamber CB2 coincide with the thickness T3 of the pressure chamber substrate 3. As shown in FIG. 6, the thickness T2 of the communication plate 2 is thicker than the thickness T3 of the pressure chamber substrate 3. The ratio between the thickness T2 and the thickness T3 can be arbitrarily set. In the present embodiment, the thickness T2 is set to be about 4 to 6 times the thickness T3.

[0052] The depth D5 of the fifth communication path RR5 is designed to be shallower than the depth DP1 of the first pressure chamber CB1 and shallower than the depth DP2 of the second pressure chamber CB2. The ratio between the depth D5 and the depth DP1, and the ratio between the depth D5 and the depth DP2 can be arbitrarily set. For example, the depth D5 can be set to be about 20% to 80% of the depth DP1 and the depth DP2. In the present embodiment, the depth D5 is set to be about 70% of the depth DP1 and the depth DP2. However, the depth D5 may be about the same as the depth DP1 or equal to the depth DP1. The depth D5 may be about the same as the depth DP2 or equal to the depth DP2.

[0053] The depth D5 of the fifth communication passage RR5 is further designed to be shallower than the depth D1 of the first communication passage RR1 and shallower than the depth D2 of the second communication passage RR2. The ratio of the depth D5 to the depth D1 and the ratio of the depth D5 to the depth D2 can be arbitrarily set. For example, the depth D5 can be set to about 20% to 80% of the depth D1 and the depth D2. In the present embodiment, the depth D5 is about 70% of the depth D1 and the depth D2. In the present embodiment, the depth D1 of the first communication passage RR1 and the depth DP1 of the first pressure chamber CB1 are substantially the same depth, and the depth D2 of the second communication passage RR2 and the depth DP2 of the second pressure chamber CB2 are set to be substantially the same depth. However, the depth D5 may be about the same as the depth D1 or equal to the depth D1. The depth D5 may also be about the same as the depth D2 or equal to the depth D2.

[0054] FIG. 7 is a cross-sectional view schematically showing the ink flow path of a conventional liquid ejection head 1R as a comparative example. As shown in FIG. 7, the liquid ejection head 1R is different from the liquid ejection head 1 of the present embodiment in the ink flow path structure in the communication plate 2. Specifically, the liquid ejection head 1R does not include the first communication passage RR1 and the second communication passage RR2 that the liquid ejection head 1 of the present embodiment has. The configurations of the first pressure chamber CB1 and the second pressure chamber CB2 and the third communication passage RR3 and the fourth communication passage RR4 are the same as those of the liquid ejection head 1 of the present embodiment. The distance between the first piezoelectric element PZ1 and the second piezoelectric element PZ2 and the distance between the first pressure chamber CB1 and the second pressure chamber CB2 are the same as those distances in the liquid ejection head 1.

[0055] The liquid ejection head 1R has a third communication passage RR3 connected to the +Z direction side at the other end of the first pressure chamber CB1, and a fourth communication passage RR4 connected to the +Z direction side at one end of the second pressure chamber CB2. On the lower surface BR of the communication plate 2, a fifth communication passage RR5 is provided between the third communication passage RR3 and the fourth communication passage RR4. The width LR5 of the fifth communication passage RR5 of the liquid ejection head 1R is longer than the width L5 of the fifth communication passage RR5 in the present embodiment. Specifically, the width LR5 is longer than the width L5 by an amount corresponding to the sum of the width L1 of the first communication passage RR1 and the width L2 of the second communication passage RR2.

[0056] In the liquid ejection head 1R, the ink inside the first pressure chamber CB1 to which pressure is applied by the first piezoelectric element PZ1 flows into the third communication passage RR3 and flows in the +Z direction. The ink that has moved to the other end of the third communication passage RR3 flows into the fifth communication passage RR5, and the flow direction is switched to the -X direction. Similarly, the ink in the second pressure chamber CB2 to which pressure is applied by the second piezoelectric element PZ2 flows from the second pressure chamber CB2 into the fourth communication passage RR4 and flows in the +Z direction. The ink that has moved to the other end of the fourth communication passage RR4 flows into the fifth communication passage RR5, and the flow direction is switched to the +X direction. Therefore, in the fifth communication passage RR5, the ink supplied from the fourth communication passage RR4 and flowing in the +X direction collides with the ink supplied from the third communication passage RR3 and flowing in the -X direction. The ink in the fifth communication passage RR5 is ejected from the nozzle Nz. In the liquid ejection head 1R, since the width LR5 of the fifth communication passage RR5 is long, compared with the liquid ejection head 1 of the present embodiment, ink collision is likely to occur in the fifth communication passage RR5, and ink flow buffering and retention are also likely to occur. In this case, there is a possibility that sufficient ink ejection performance from the nozzle Nz cannot be obtained.

[0057] In the conventional liquid ejection head 1R, the residence time of the ink in the fifth communication passage RR5 is longer than that in the fifth communication passage RR5 of the present embodiment by the amount that the width becomes longer. Therefore, for example, the ink in the fifth communication passage RR5 is likely to dissipate heat to the outside of the liquid ejection head 1R through the nozzle substrate 60. Due to this heat dissipation, there is a risk that the temperature of the ink will become lower than the assumed value. When the temperature of the ink changes, the viscosity of the ink also changes. The viscosity of the ink can greatly affect the ejection characteristics. Therefore, in the conventional liquid ejection head 1R, there is a risk that the actual ejection characteristics will deviate from the desired ejection characteristics due to the heat dissipation of the ink in the fifth communication passage RR5 to the outside.

[0058] On the other hand, in the liquid ejection head 1 of the present embodiment, the first communication passage RR1 and the second communication passage RR2 are connected to the first pressure chamber CB1 and the second pressure chamber CB2. By forming a flow path extending from the pressure chamber CBq in a direction approaching the nozzle Nz along the X-axis direction, the width L5 of the fifth communication passage RR5 directly above the nozzle Nz is set to be shorter than that of the conventional liquid ejection head 1R.

[0059] Since the distances from the third communication passage RR3 and the fourth communication passage RR4 to the nozzle Nz are shortened, the kinetic energy of the ink in the Z-axis direction is more likely to remain directly above the nozzle Nz compared to the conventional liquid ejection head 1R. Therefore, the ink can be more easily ejected from the nozzle Nz compared to the conventional liquid ejection head 1R in which the distances from the third communication passage RR3 and the fourth communication passage RR4 to the nozzle Nz are long. Also, in the fifth communication passage RR5, the kinetic energy of the ink in the X-axis direction becomes weaker than before, and the buffering and retention of the ink flow due to the collision of the ink can be alleviated.

[0060] In the liquid ejection head 1 of the present embodiment, by making the width L5 of the fifth communication passage RR5 shorter than before, the period during which the ink stays in the fifth communication passage RR5 is shortened. Therefore, according to the liquid ejection head 1 of the present embodiment, heat dissipation of the ink in the fifth communication passage RR5 to the outside through the nozzle substrate 60 is reduced, thereby reducing temperature changes and viscosity changes of the ink, and thus reducing or preventing a decrease in the ejection performance of the ink.

[0061] Furthermore, in the liquid ejection head 1 of the present embodiment, by providing the first communication passage RR1 and the second communication passage RR2 on the upper surface TR of the communication plate 2, the ink flow path can be provided closer to the wiring substrate 8 mounted between the first piezoelectric element PZ1 and the second piezoelectric element PZ2 than before. Therefore, the ink in the flow path is more likely to be heat-transferred by the heat generated in the wiring substrate 8. For this reason, even if heat dissipation of the ink to the outside occurs in the fifth communication passage RR5, the temperature of the ink can be maintained in the first communication passage RR1 and the second communication passage RR2, thereby further reducing or preventing temperature changes and viscosity changes of the ink. As a result, it is possible to reduce or prevent a decrease in the ejection performance of the ink from the nozzles Nz as compared with the conventional liquid ejection head 1R.

[0062] As described above, the liquid ejection head 1 of the present embodiment includes a first pressure chamber CB1 extending along a first direction, a second pressure chamber CB2 extending along the first direction, a first communication passage RR1 connected to the first pressure chamber CB1 and extending along the first direction, a second communication passage RR2 connected to the second pressure chamber CB2 and extending along the first direction, a third communication passage RR3 connected to the first communication passage RR1 and extending along a second direction intersecting the first direction, a fourth communication passage RR4 connected to the second communication passage RR2 and extending along the second direction, a fifth communication passage RR5 connected to the third communication passage RR3 and the fourth communication passage RR4 and extending along the first direction, and a nozzle Nz provided in the fifth communication passage RR5. According to the liquid ejection head 1 of the present embodiment, by providing the first communication passage RR1 and the second communication passage RR2 extending in the X-axis direction from the first pressure chamber CB1 and the second pressure chamber CB2, the width L5 of the fifth communication passage RR5 can be shortened. Therefore, in the fifth communication passage RR5, the kinetic energy of the ink supplied from the third communication passage RR3 and the fourth communication passage RR4 in the Z-axis direction is likely to remain, and the ink is more likely to be ejected from the nozzle Nz than in the conventional liquid ejection head 1R. Further, in the fifth communication passage RR5, the kinetic energy of the ink in the X-axis direction becomes weaker than before, and the buffer and retention of the ink flow due to the collision of the ink can be alleviated. Therefore, it is possible to reduce or prevent the deterioration of the ejection performance of the ink from the nozzle Nz. Further, since the period during which the ink stays in the fifth communication passage RR5 is shorter than before, the problem that the ink in the fifth communication passage RR5 is affected by external heat through the nozzle substrate 60 is reduced, and the deterioration of the ejection performance of the ink can be reduced or prevented.

[0063] According to the liquid ejection head 1 of the present embodiment, the width of the fifth communication passage RR5 is shorter than the width of the first communication passage RR1 and shorter than the width of the second communication passage RR2. By setting the width L5 of the fifth communication passage RR5 to be shorter than the widths L1 and L2 of the first communication passage RR1 and the second communication passage RR2 among the flow paths extending in the X-axis direction, the width L5 of the fifth communication passage RR5 can be designed to be smaller, and it is possible to reduce or prevent the deterioration of the ejection performance of the ink.

[0064] According to the liquid ejection head 1 of the present embodiment, the width L5 of the fifth communication passage RR5 is shorter than the sum of the width L1 of the first communication passage RR1 and the width L2 of the second communication passage RR2. By setting the width L5 of the fifth communication passage RR5 to be shorter than the sum of the widths L1 and L2 of the first communication passage RR1 and the second communication passage RR2 among the flow paths extending in the X-axis direction, the width L5 of the fifth communication passage RR5 can be designed to be smaller, and it is possible to reduce or prevent a decrease in the ink ejection performance.

[0065] According to the liquid ejection head 1 of the present embodiment, the width L5 of the fifth communication passage RR5 is shorter than the width LP1 of the first pressure chamber CB1 and shorter than the width LP2 of the second pressure chamber CB2. By setting the width L5 of the fifth communication passage RR5 to be shorter than the widths LP1 and LP2 of the first pressure chamber CB1 and the second pressure chamber CB2 among the flow paths extending in the X-axis direction, the width L5 of the fifth communication passage RR5 can be designed to be smaller, and it is possible to reduce or prevent a decrease in the ink ejection performance.

[0066] According to the liquid ejection head 1 of the present embodiment, the width L1 of the first communication passage RR1 is shorter than the width LP1 of the first pressure chamber CB1, and the width L2 of the second communication passage RR2 is shorter than the width LP2 of the second pressure chamber CB2. By suppressing the widths L1 and L2 of the first communication passage RR1 and the second communication passage RR2 from becoming larger than the widths LP1 and LP2 of the first pressure chamber CB1 and the second pressure chamber CB2, it is possible to suppress the ink flow path from becoming excessively long, and to reduce or suppress a decrease in the ink ejection performance and an excessive increase in the size of the liquid ejection head 1.

[0067] According to the liquid ejection head 1 of the present embodiment, the depth D5 of the fifth communication passage RR5 is shallower than the depth D1 of the first communication passage RR1 and shallower than the depth D2 of the second communication passage RR2. By designing the cross-sectional areas of the flow paths of the first communication passage RR1 and the second communication passage RR2 to be large, the flow path resistance in the first communication passage RR1 and the second communication passage RR2 can be reduced, and in the fifth communication passage RR5 which is easily affected by the outside air and has a high viscosity, the ink ejection performance can be improved by increasing the flow velocity of the ink.

[0068] According to the liquid ejection head 1 of the present embodiment, the depth D5 of the fifth communication passage RR5 is shallower than the depth DP1 of the first pressure chamber CB1 and shallower than the depth DP2 of the second pressure chamber CB2. By designing the cross-sectional areas of the flow paths in the first pressure chamber CB1 and the second pressure chamber CB2 to be large, the flow path resistance in the first pressure chamber CB1 and the second pressure chamber CB2 is reduced, and in the fifth communication passage RR5 which is easily affected by the outside air and has a high viscosity tendency, the ink flow velocity is increased, so that the ink ejection performance can be improved.

[0069] According to the liquid ejection head 1 of the present embodiment, the first communication passage RR1 is defined by a first communication plate groove formed on the upper surface TR of the communication plate 2 and the lower surface BC of the pressure chamber substrate 3 facing the upper surface TR of the communication plate 2. The second communication passage RR2 is defined by a second communication plate groove formed on the upper surface TR of the communication plate 2 and the lower surface BC of the pressure chamber substrate 3 facing the upper surface TR of the communication plate 2. Therefore, the connection of the flow paths between the first communication passage RR1 and the second communication passage RR2, and the first pressure chamber CB1 and the second pressure chamber CB2 becomes easy. Also, compared with the form in which the first communication passage RR1 and the second communication passage RR2 are provided at the center in the thickness direction of the communication plate 2, the first communication passage RR1 and the second communication passage RR2 can be easily formed on the communication plate 2.

[0070] According to the liquid ejection head 1 of the present embodiment, the third communication passage RR3, the fourth communication passage RR4, and the fifth communication passage RR5 are provided on the communication plate 2. Therefore, compared with the form in which the third communication passage RR3, the fourth communication passage RR4, and the fifth communication passage RR5 are formed across a plurality of substrates, they can be easily formed.

[0071] According to the liquid ejection head 1 of the present embodiment, the third communication passage RR3 and the fourth communication passage RR4 are through holes penetrating the communication plate 2 along the Z direction. The fifth communication passage RR5 is defined by a third communication plate groove formed on the lower surface BR of the communication plate 2 and the upper surface TN of the nozzle substrate 60. Compared with the form in which the fifth communication passage RR5 is provided at the center in the thickness direction of the communication plate 2, it becomes easy to form the fifth communication passage RR5.

[0072] According to the liquid ejection head 1 of the present embodiment, the thickness T2 of the communication plate 2 is thicker than the thickness T3 of the pressure chamber substrate 3. Therefore, it becomes easy to form a plurality of flow paths in the communication plate 2.

[0073] According to the liquid ejection head 1 of the present embodiment, a first piezoelectric element PZ1 for varying the pressure in the first pressure chamber CB1, a second piezoelectric element PZ2 for varying the pressure in the second pressure chamber CB2, and a wiring substrate 8 provided between the first piezoelectric element PZ1 and the second piezoelectric element PZ2 for supplying power to the first piezoelectric element PZ1 and the second piezoelectric element PZ2 are provided. By providing the first communication path RR1 and the second communication path RR2 at positions close to the wiring substrate 8, the ink is likely to receive heat transfer from the wiring substrate 8. For example, problems such as a decrease in the viscosity of the ink can be reduced or prevented, and a decrease in the ejection performance of the ink from the nozzle Nz can be reduced or prevented.

[0074] According to the liquid ejection head 1 of the present embodiment, further, a plurality of individual flow paths including a first pressure chamber CB1, a second pressure chamber CB2, a first communication path RR1, a second communication path RR2, a third communication path RR3, a fourth communication path RR4, and a fifth communication path RR5 are provided. A common supply channel RA1 that communicates in common with the plurality of individual channels and supplies ink to each of the plurality of individual channels, and a common discharge channel RA2 that communicates in common with the plurality of individual channels and discharges ink from each of the plurality of individual channels are provided. In the liquid ejection head 1 having an ink circulation structure, a decrease in the ejection performance of the ink from the nozzle Nz can be reduced or prevented.

[0075] B. Second Embodiment: The configuration of the liquid ejection head 1b as the second embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a cross-sectional view showing the internal structure of the liquid ejection head 1b as the second embodiment. In FIGS. 8 and 9, for ease of understanding of the technology, the boundaries between the respective flow paths are schematically shown using broken lines. The liquid ejection head 1b of the second embodiment is different from the liquid ejection head 1 of the first embodiment in that it includes a first communication passage RR1b and a second communication passage RR2b instead of the first communication passage RR1 and the second communication passage RR2, and the other configurations are the same. Note that the distance between the first piezoelectric element PZ1 and the second piezoelectric element PZ2 and the distance between the first pressure chamber CB1 and the second pressure chamber CB2 are also the same as those in the liquid ejection head 1.

[0076] In the first embodiment, an example was shown in which the first communication passage RR1 and the second communication passage RR2 are flow paths defined by a groove formed on the upper surface TR of the communication plate 2 by etching of the communication plate 2 and the lower surface BC of the pressure chamber substrate 3. On the other hand, as shown in FIG. 8, in the present embodiment, the first communication passage RR1b is a flow path defined by a first communication plate groove portion RR12 formed on the upper surface TR of the communication plate 2 and a groove RR11 formed on the lower surface BC of the pressure chamber substrate 3 by etching of the pressure chamber substrate 3. Among the grooves formed on the lower surface BC of the pressure chamber substrate 3, the groove RR11 corresponding to the first communication passage RR1b is also referred to as the "first pressure chamber substrate groove portion RR11".

[0077] The second communication passage RR2b is a flow path defined by a second communication plate groove portion RR22 formed on the upper surface TR of the communication plate 2 and a groove RR21 formed on the lower surface BC of the pressure chamber substrate 3 by etching of the pressure chamber substrate 3. Among the grooves formed on the lower surface BC of the pressure chamber substrate 3, the groove RR21 corresponding to the second communication passage RR2b is also referred to as the "second pressure chamber substrate groove portion RR21".

[0078] FIG. 9 is an explanatory diagram showing an enlarged cross-section of a flow path near the nozzle Nz of the liquid ejection head 1b as a second embodiment. In FIG. 9, the depth D21 of the first communication path RR1b and the depth D22 of the second communication path RR2b are shown. In the present embodiment, the depth D21 of the first communication path RR1b is substantially the same as the depth DP1 of the first pressure chamber CB1. The depth D21 is the sum of the depth D211 of the first pressure chamber substrate groove portion RR11 and the depth D212 of the first communication plate groove portion RR12. In the present embodiment, the depth D221 of the groove RR21 and the depth D222 of the groove RR22 are set to be equal to each other, but the present invention is not limited thereto, and they may be set to different depths from each other.

[0079] In the present embodiment, the depth D22 of the second communication path RR2b is substantially the same as the depth DP2 of the second pressure chamber CB2. The depth D22 of the second communication path RR2b is the sum of the depth D221 of the second pressure chamber substrate groove portion RR21 and the depth D222 of the second communication plate groove portion RR22. In the present embodiment, the depth D221 of the groove RR21 and the depth D222 of the groove RR22 are set to be equal to each other, but the present invention is not limited thereto, and they may be set to different depths from each other.

[0080] In the present embodiment, the fifth communication path RR5 is formed by the same process as the etching process for forming the first communication plate groove portion RR12 and the second communication plate groove portion RR22. Thereby, the manufacturing process can be simplified and the cost can be reduced. Further, in the present embodiment, the etching rates of the fifth communication path RR5, the first communication plate groove portion RR12, and the second communication plate groove portion RR22 are made the same. Thereby, the depth D5 of the fifth communication path RR5 is made equal to the depth D212 of the first communication plate groove portion RR12 and equal to the depth D222 of the second communication plate groove portion RR22.

[0081] As shown in FIG. 9, in the present embodiment, the width L21 of the first communication passage RR1b is shorter than the width L1 of the first communication passage RR1 in the first embodiment. This is because, in the first embodiment, the first communication passage RR1 is connected to the end portion of the first pressure chamber CB1 on the +Z direction side, while in the present embodiment, the first communication passage RR1b is connected to the end portion of the first pressure chamber CB1 on the -X direction side. In the present embodiment, the width L21 of the first communication passage RR1b is substantially equal to the width L5 of the fifth communication passage RR5. The width of the first pressure chamber substrate groove portion RR11 and the width of the first communication plate groove portion RR12 are equal to each other and equal to the width L21 of the first communication passage RR1b. However, for example, the width of the first communication plate groove portion RR12 may be made larger than the width L21. In this case, the first communication plate groove portion RR12 may have a structure extending to the +Z direction side of the first pressure chamber CB1, for example, and may be connected to the +Z direction side of the first pressure chamber CB1. Similarly, the width of the groove RR11 may be made larger than the width L21, and in this case, it may be connected by centrifuging to the -Z direction side of the third communication passage RR3.

[0082] In the present embodiment, the width L22 of the second communication passage RR2b is shorter than the width L2 of the second communication passage RR2 in the first embodiment. This is because, in the first embodiment, the second communication passage RR2 is connected to the end portion of the second pressure chamber CB2 on the +Z direction side, while in the present embodiment, the second communication passage RR2b is connected to the end portion of the second pressure chamber CB2 on the +X direction side. In the present embodiment, the width L22 of the second communication passage RR2b is substantially equal to the width L5 of the fifth communication passage RR5. However, for example, the width of the second communication plate groove portion RR22 may be made larger than the width L22. In this case, the second communication plate groove portion RR22 may have a structure extending to the +Z direction side of the second pressure chamber CB2, for example, and may be connected to the +Z direction side of the second pressure chamber CB2. Similarly, the width of the groove RR21 may be made larger than the width L22, and in this case, it may be connected by extending to the -Z direction side of the fourth communication passage RR4.

[0083] According to the liquid ejection head 1b of the present embodiment, the first communication passage RR1b is a flow path defined by a first communication plate groove portion RR12 formed on the upper surface TR of the communication plate 2 and a groove RR11 formed on the lower surface BC of the pressure chamber substrate 3. The second communication passage RR2b is a flow path defined by a second communication plate groove portion RR22 formed on the upper surface TR of the communication plate 2 and a groove RR21 formed on the lower surface BC of the pressure chamber substrate 3. Therefore, by forming a part of the flow paths of the first communication passage RR1b and the second communication passage RR2b in the pressure chamber substrate 3, an increase in inertia in the first communication passage RR1b and the second communication passage RR2b can be reduced or prevented.

[0084] According to the liquid ejection head 1b of the present embodiment, the depth D5 of the fifth communication passage RR5 is equal to the depth D212 of the first communication plate groove portion RR12 and is also equal to the depth D222 of the second communication plate groove portion RR22. The etching rates of the fifth communication passage RR5, the first communication passage RR1b, and the second communication passage RR2b can be made the same, and it becomes easy to form the fifth communication passage RR5, the first communication passage RR1b, and the second communication passage RR2b in the same process.

[0085] C. Other embodiments: The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each of the embodiments described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0086] (1) According to one embodiment of the present disclosure, a liquid ejection head is provided. This liquid ejection head includes a first pressure chamber extending along a first direction, a second pressure chamber extending along the first direction, a first communication passage connected to the first pressure chamber and extending along the first direction, a second communication passage connected to the second pressure chamber and extending along the first direction, a third communication passage connected to the first communication passage and extending along a second direction intersecting the first direction, a fourth communication passage connected to the second communication passage and extending along the second direction, a fifth communication passage connected to the third communication passage and the fourth communication passage and extending along the first direction, and a nozzle provided in the fifth communication passage. According to the liquid ejection head of this embodiment, by providing the first communication passage and the second communication passage extending in the first direction from the first pressure chamber and the second pressure chamber, the length of the fifth communication passage in the first direction can be shortened. In the fifth communication passage, the kinetic energy of the liquid in the second direction supplied from the third communication passage and the fourth communication passage is likely to remain, and the kinetic energy in the first direction is likely to become weak. As a result, buffering and retention of the liquid flow due to the collision of the liquids in the fifth communication passage can be alleviated. Therefore, it is possible to reduce or prevent the deterioration of the liquid ejection performance from the nozzle.

[0087] (2) In the liquid ejection head of the above embodiment, the length of the fifth communication passage in the first direction may be shorter than the length of the first communication passage in the first direction, and may also be shorter than the length of the second communication passage in the first direction. According to the liquid ejection head of this embodiment, the length of the fifth communication passage in the first direction can be designed to be smaller, and it is possible to reduce or prevent the deterioration of the liquid ejection performance.

[0088] (3) In the liquid ejection head of the above embodiment, the length of the fifth communication passage in the first direction may be shorter than the sum of the length of the first communication passage in the first direction and the length of the second communication passage in the first direction. According to the liquid ejection head of this embodiment, the length of the fifth communication passage in the first direction can be designed to be smaller, and it is possible to reduce or prevent the deterioration of the liquid ejection performance.

[0089] (4) In the liquid ejection head of the above-described embodiment, the length of the fifth communication passage in the first direction may be shorter than the length of the first pressure chamber in the first direction, and may also be shorter than the length of the second pressure chamber in the first direction. According to the liquid ejection head of this embodiment, the length of the fifth communication passage in the first direction can be designed to be smaller, and it is possible to reduce or prevent the reduction of the liquid ejection performance.

[0090] (5) In the liquid ejection head of the above-described embodiment, the length of the fifth communication passage in the first direction may be shorter than the sum of the length of the first pressure chamber in the first direction and the length of the second pressure chamber in the first direction. According to the liquid ejection head of this embodiment, the length of the fifth communication passage in the first direction can be designed to be smaller, and it is possible to reduce or prevent the reduction of the liquid ejection performance.

[0091] (6) In the liquid ejection head of the above-described embodiment, the length of the first communication passage in the first direction may be shorter than the length of the first pressure chamber in the first direction, and the length of the second communication passage in the first direction may also be shorter than the length of the second pressure chamber in the first direction. According to the liquid ejection head of this embodiment, it is possible to suppress the excessive lengthening of the liquid flow path, and reduce or suppress the reduction of the liquid ejection performance and the increase in the size of the liquid ejection head.

[0092] (7) In the liquid ejection head of the above-described embodiment, the length of the fifth communication passage in the first direction may be shorter than the sum of the length of the first communication passage in the first direction, the length of the second communication passage in the first direction, the length of the first pressure chamber in the first direction, and the length of the second pressure chamber in the first direction. According to the liquid ejection head of this embodiment, the length of the fifth communication passage in the first direction can be designed to be smaller, and it is possible to reduce or prevent the reduction of the liquid ejection performance.

[0093] (8) In the liquid ejection head of the above-described embodiment, the length of the fifth communication passage in the second direction may be shorter than the length of the first communication passage in the second direction and shorter than the length of the second communication passage in the second direction. According to the liquid ejection head of this embodiment, while reducing the flow path resistance in the first communication passage and the second communication passage, the flow rate of the liquid is increased in the fifth communication passage which is easily affected by the outside air and has a high viscosity, so that the ejection performance of the liquid can be improved.

[0094] (9) In the liquid ejection head of the above-described embodiment, the length of the fifth communication passage in the second direction may be equal to the length of the first communication passage in the second direction and equal to the length of the second communication passage in the second direction. According to the liquid ejection head of this embodiment, the manufacturing cost can be reduced.

[0095] (10) In the liquid ejection head of the above-described embodiment, the length of the fifth communication passage in the second direction may be shorter than the length of the first pressure chamber in the second direction and shorter than the length of the second pressure chamber in the second direction. According to the liquid ejection head of this embodiment, while reducing the flow path resistance in the first pressure chamber and the second pressure chamber, the flow rate of the liquid is increased in the fifth communication passage which is easily affected by the outside air and has a high viscosity, so that the ejection performance of the liquid can be improved.

[0096] (11) In the liquid ejection head of the above-described embodiment, it may have a communication plate including the first communication passage, the second communication passage, the third communication passage, the fourth communication passage, and the fifth communication passage, a pressure chamber substrate laminated on one surface of the communication plate and including the first pressure chamber and the second pressure chamber, and a nozzle substrate laminated on the other surface of the communication plate and including the nozzle.

[0097] (12) In the liquid ejection head of the above-described form, the first communication passage may be defined by a first communication plate groove portion formed on one surface of the communication plate and one surface of the pressure chamber substrate facing the one surface of the communication plate, and the second communication passage may be defined by a second communication plate groove portion formed on one surface of the communication plate and one surface of the pressure chamber substrate facing the one surface of the communication plate. According to the liquid ejection head of this form, the connection of the flow paths of the first communication passage and the second communication passage, and the first pressure chamber and the second pressure chamber becomes easy.

[0098] (13) In the liquid ejection head of the above-described form, the first communication passage may be defined by a first communication plate groove portion formed on one surface of the communication plate and a first pressure chamber substrate groove portion formed on one surface of the pressure chamber substrate facing the one surface of the communication plate. The second communication passage may be defined by a second communication plate groove portion formed on one surface of the communication plate and a second pressure chamber substrate groove portion formed on one surface of the pressure chamber substrate facing the one surface of the communication plate. According to the liquid ejection head of this form, by forming a part of the flow paths of the first communication passage and the second communication passage in the pressure chamber substrate, an increase in inertia in the first communication passage and the second communication passage can be reduced or prevented.

[0099] (14) In the liquid ejection head of the above-described form, the length of the fifth communication passage in the second direction may be equal to the length of the first communication plate groove portion in the second direction and equal to the length of the second communication plate groove portion in the second direction. According to the liquid ejection head of this form, it becomes easy to form the fifth communication passage, the first communication passage, and the second communication passage in the same process.

[0100] (15) In the liquid ejection head of the above-described form, the third communication passage, the fourth communication passage, and the fifth communication passage may be provided on the communication plate. According to the liquid ejection head of this form, it can be easily formed as compared with a form in which the third communication passage, the fourth communication passage, and the fifth communication passage are formed across a plurality of substrates.

[0101] (16) In the liquid ejection head of the above-described embodiment, the third communication passage and the fourth communication passage may be through holes that penetrate the communication plate along the second direction, and the fifth communication passage may be defined by a third communication plate groove formed on the other surface of the communication plate and one surface of the nozzle substrate facing the other surface of the communication plate. According to the liquid ejection head of this embodiment, it is easier to form the fifth communication passage compared to the form in which the fifth communication passage is provided at the center in the thickness direction of the communication plate.

[0102] (17) In the liquid ejection head of the above-described embodiment, the thickness of the communication plate in the second direction may be greater than the thickness of the pressure chamber substrate in the second direction. According to the liquid ejection head of this embodiment, it is easy to form a plurality of flow paths in the communication plate.

[0103] (18) In the liquid ejection head of the above-described embodiment, a first piezoelectric element for varying the pressure in the first pressure chamber, a second piezoelectric element for varying the pressure in the second pressure chamber, and a wiring substrate provided between the first piezoelectric element and the second piezoelectric element for supplying power to the first piezoelectric element and the second piezoelectric element may be provided. According to the liquid ejection head of this embodiment, the liquid is likely to receive heat transfer from the wiring substrate, reducing or suppressing a decrease in the viscosity of the liquid, and reducing or preventing a decrease in the ejection performance of the liquid.

[0104] (19) In the liquid ejection head of the above-described embodiment, further, individual flow paths including the first pressure chamber, the second pressure chamber, the first communication passage, the second communication passage, the third communication passage, the fourth communication passage, and the fifth communication passage, a plurality of individual flow paths, a common supply passage that communicates in common with the plurality of individual flow paths and supplies liquid to each of the plurality of individual flow paths, and a common discharge passage that communicates in common with the plurality of individual flow paths and discharges liquid from each of the plurality of individual flow paths may be provided. According to the liquid ejection head of this embodiment, in a liquid ejection head having a liquid circulation structure, it is possible to reduce or prevent a decrease in the ejection performance of the liquid from the nozzles.

[0105] (20) According to another aspect of the present disclosure, a liquid ejection device is provided. The liquid ejection device includes the liquid ejection head of the above aspect and a control device that controls the liquid ejection operation from the liquid ejection head.

[0106] The present disclosure can also be realized in various forms other than the liquid ejection head and the liquid ejection device. For example, it can be realized in forms such as a flow path structure, a method for manufacturing a liquid ejection head, and a method for manufacturing a liquid ejection device.

[0107] The present disclosure is not limited to the inkjet method and can also be applied to any liquid ejection device that ejects liquids other than ink and the liquid ejection heads used in those liquid ejection devices. For example, it is applicable to the following various liquid ejection devices and their liquid ejection heads. (1) An image recording device such as a facsimile machine. (2) A colorant ejection device used for manufacturing a color filter for an image display device such as a liquid crystal display. (3) An electrode material ejection device used for forming electrodes in an organic EL (Electro Luminescence) display, a field emission display (FED), or the like. (4) A liquid ejection device that ejects a liquid containing a biological organic substance used for manufacturing a biochip. (5) A sample ejection device as a precision pipette. (6) A lubricating oil ejection device. (7) A resin liquid ejection device. (8) A liquid ejection device that ejects lubricating oil pinpoint to precision machinery such as watches and cameras. (9) A liquid ejection device that ejects a transparent resin liquid such as an ultraviolet curable resin liquid onto a substrate to form a micro hemispherical lens (optical lens) or the like used in an optical communication element or the like. (10) A liquid ejection device that ejects an acidic or alkaline etching liquid for etching a substrate or the like. (11) A liquid ejection device including a liquid consumption head that ejects any other minute droplets.

[0108] The term "droplet" refers to the state of the liquid ejected from the liquid ejection device, and includes those trailing in a granular, teardrop-like, or filamentous form. Also, the "liquid" may be any material that can be consumed by the liquid ejection device. For example, the "liquid" may be a material in a state when the substance is in a liquid phase, and includes liquid-state materials with high or low viscosity, as well as liquid-state materials such as sols, gels, water, other inorganic solvents, organic solvents, solutions, liquid resins, and liquid metals (molten metals). Further, not only liquids as a state of matter, but also those in which particles of functional materials composed of solids such as pigments and metal particles are dissolved, dispersed, or mixed in a solvent are included in the "liquid". Also, as typical examples of the combination of the first liquid and the second liquid, in addition to the combination of ink and reaction liquid as described in the above embodiments, the following are included. (1) The main agent and curing agent of the adhesive (2) The base paint and thinner of the paint, and the clear paint and thinner (3) The main solvent and diluting solvent containing cells of the cell ink (4) The metallic leaf pigment dispersion liquid and diluting solvent of the ink (metallic ink) that exhibits a metallic luster (5) Gasoline, light oil, and biofuel for vehicle fuel (6) The main drug component and protective component of the drug (7) The phosphor and encapsulant of the light-emitting diode (LED)

Explanation of reference numerals

[0109] 1, 1b, 1R… Liquid ejection head, 2… Communication board, 3… Pressure chamber substrate, 4… Diaphragm, 5… Reservoir formation substrate, 8… Wiring board, 50… Opening, 51… Inlet, 52… Outlet, 60… Nozzle substrate, 61, 62… Compliance sheet, 81… Drive circuit, 90… Control device, 91… Moving mechanism, 92… Conveyor mechanism, 93… Liquid container, 94… Circulation mechanism, 100… Liquid ejection device, 810… Wiring, 921… Storage case, 922… Endless belt, CB1… First pressure chamber, CB2… Second pressure chamber, CBq… Pressure chamber, Ln… Nozzle row, Nz… Nozzle, PP… Medium, PZ1… First piezoelectric element, PZ2… Second piezoelectric element, PZq… Piezoelectric element, RA1… Common supply flow path, RA2… Common discharge flow path, RB1… Common supply flow path, RB2… Common discharge flow path, RJ… Circulation flow path, RK1, RK2, RX1, RX2… Communication flow path, RR1, RR1b… First communication path, RR11… First pressure chamber substrate groove, RR12… First communication board groove, RR2, RR2b… Second communication path, RR21… Second pressure chamber substrate groove, RR22… Second communication board groove, RR3… Third communication path, RR4… Fourth communication path, RR5… Fifth communication path, ZDq… Lower electrode, ZMq… Piezoelectric body, ZUq… Upper electrode

Claims

1. A liquid ejection head, comprising: a pressure chamber substrate provided with a first pressure chamber extending along a first direction and a second pressure chamber extending along the first direction; a nozzle substrate provided with nozzles; a third communication passage extending along a second direction intersecting the first direction with the pressure chamber substrate and the nozzle substrate at both ends; a fourth communication passage extending along the second direction with the pressure chamber substrate and the nozzle substrate at both ends; a first communication passage connected to the first pressure chamber and the third communication passage and extending along the first direction within a range not overlapping the third communication passage; a second communication passage connected to the second pressure chamber and the fourth communication passage and extending along the first direction within a range not overlapping the fourth communication passage; a fifth communication passage connected to the third communication passage and the fourth communication passage, extending along the first direction within a range not overlapping the third communication passage and the fourth communication passage, and having the nozzles provided therein; and wherein a length of the fifth communication passage in the first direction is shorter than a sum of a length of the first communication passage in the first direction and a length of the second communication passage in the first direction. A liquid ejection head.

2. The liquid ejection head according to Claim 1, wherein the length of the fifth communication passage in the first direction is shorter than the length of the first communication passage in the first direction and shorter than the length of the second communication passage in the first direction. A liquid ejection head.

3. The liquid ejection head according to Claim 1 or Claim 2, wherein the length of the fifth communication passage in the first direction is shorter than the length of the first pressure chamber in the first direction and shorter than the length of the second pressure chamber in the first direction. A liquid ejection head.

4. The liquid ejection head according to any one of Claims 1 to 3, wherein the length of the fifth communication passage in the first direction is shorter than a sum of the length of the first pressure chamber in the first direction and the length of the second pressure chamber in the first direction. A liquid ejection head.

5. The liquid ejection head according to Claim 3 or Claim 4, wherein the length of the first communication passage in the first direction is shorter than the length of the first pressure chamber in the first direction, and the length of the second communication passage in the first direction is shorter than the length of the second pressure chamber in the first direction. A liquid ejection head.

6. The liquid ejection head according to any one of Claims 1 to 5, The length of the fifth communication path in the first direction is shorter than the sum of the length of the first communication path in the first direction, the length of the second communication path in the first direction, the length of the first pressure chamber in the first direction, and the length of the second pressure chamber in the first direction. Liquid ejection head.

7. The liquid ejection head according to any one of Claims 1 to 6, The length of the fifth communication path in the second direction is shorter than the length of the first communication path in the second direction and shorter than the length of the second communication path in the second direction. Liquid ejection head.

8. The liquid ejection head according to any one of Claims 1 to 6, The length of the fifth communication path in the second direction is equal to the length of the first communication path in the second direction and equal to the length of the second communication path in the second direction. Liquid ejection head.

9. The liquid ejection head according to any one of Claims 1 to 8, The length of the fifth communication path in the second direction is shorter than the length of the first pressure chamber in the second direction and shorter than the length of the second pressure chamber in the second direction. Liquid ejection head.

10. The liquid ejection head according to any one of Claims 1 to 9, Comprising a communication plate including the first communication path, the second communication path, the third communication path, the fourth communication path, and the fifth communication path. The pressure chamber substrate is laminated on one surface of the communication plate. The nozzle substrate is laminated on the other surface of the communication plate. Liquid ejection head.

11. The liquid ejection head according to Claim 10, The first communication path is defined by a first communication plate groove formed on one surface of the communication plate and one surface of the pressure chamber substrate facing one surface of the communication plate. The second communication path is defined by a second communication plate groove formed on one surface of the communication plate and one surface of the pressure chamber substrate facing one surface of the communication plate. Liquid ejection head.

12. The liquid ejection head according to Claim 10, The first communication path is defined by a first communication plate groove formed on one surface of the communication plate and a first pressure chamber substrate groove formed on one surface of the pressure chamber substrate facing one surface of the communication plate. The second communication path is defined by a second communication plate groove portion formed on one surface of the communication plate and a second pressure chamber substrate groove portion formed on one surface of the pressure chamber substrate facing the one surface of the communication plate. Liquid ejection head.

13. The liquid ejection head according to claim 12, wherein a length of the fifth communication path in the second direction is equal to a length of the first communication plate groove portion in the second direction and is equal to a length of the second communication plate groove portion in the second direction. Liquid ejection head.

14. The liquid ejection head according to any one of claims 10 to 13, wherein the third communication path, the fourth communication path, and the fifth communication path are provided in the communication plate.

15. The liquid ejection head according to any one of claims 10 to 14, wherein the third communication path and the fourth communication path are through holes penetrating the communication plate along the second direction, and the fifth communication path is defined by a third communication plate groove portion formed on the other surface of the communication plate and one surface of the nozzle substrate facing the other surface of the communication plate. Liquid ejection head.

16. The liquid ejection head according to any one of claims 10 to 15, wherein a thickness of the communication plate in the second direction is thicker than a thickness of the pressure chamber substrate in the second direction. Liquid ejection head.

17. The liquid ejection head according to any one of claims 1 to 16, comprising a first piezoelectric element for varying a pressure in the first pressure chamber, a second piezoelectric element for varying a pressure in the second pressure chamber, and a wiring substrate provided between the first piezoelectric element and the second piezoelectric element for supplying power to the first piezoelectric element and the second piezoelectric element. Liquid ejection head.

18. The liquid ejection head according to any one of claims 1 to 17, further comprising a plurality of individual flow paths including the first pressure chamber, the second pressure chamber, the first communication path, the second communication path, the third communication path, the fourth communication path, and the fifth communication path, a common supply flow path that commonly communicates with the plurality of individual flow paths and supplies liquid to each of the plurality of individual flow paths, and a common discharge flow path that commonly communicates with the plurality of individual flow paths and discharges liquid from each of the plurality of individual flow paths. Liquid ejection head.

19. A liquid ejection head according to any one of claims 1 to 18, and a control device that controls a liquid ejection operation from the liquid ejection head, comprising a liquid ejection device.

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