Liquid dispensing head

Abstract

To provide a liquid discharge head that can improve the strength of the flow path section. [Solution] A liquid discharge head according to one embodiment comprises a nozzle plate having a plurality of nozzles for discharging droplets, a first flow path substrate having a first flow path portion communicating with the nozzles, and a second flow path substrate having a second flow path portion communicating with the first flow path portion, wherein the second flow path portion of the second flow path substrate has a connecting wall portion in the middle of the extension direction that spans the width direction intersecting the extension direction.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejection head.

Background Art

[0002] In a liquid ejection head such as an inkjet head, a diaphragm is deformed by using an actuator composed of a piezoelectric material such as PZT (lead zirconate titanate), and a pressure chamber facing the diaphragm is deformed to eject ink from a nozzle communicating with the pressure chamber. The liquid ejection head includes a plurality of actuators joined to the diaphragm, and a flow path portion that forms a plurality of pressure chambers facing the diaphragm and flow paths communicating with the pressure chambers. In the flow path portion of such an inkjet head, there is one in which a plurality of flow path plates having slits of a predetermined shape are laminated to form the flow path portion. Depending on the shape of the flow path, it becomes an elongated slit, so the strength is weak and it becomes difficult to ensure the flow path shape. Particularly in a circulation system in which flow paths are formed on both sides of the pressure chamber and ink circulates, the slit becomes longer and thinner.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a liquid ejection head capable of improving the strength of the flow path portion.

Means for Solving the Problems

[0005] A liquid discharge head according to one embodiment comprises a nozzle plate having a plurality of nozzles for discharging droplets, a first flow path substrate having a first flow path portion communicating with the nozzles, and a second flow path substrate having a second flow path portion communicating with the first flow path portion, wherein the second flow path portion of the second flow path substrate has a connecting wall portion in the middle of the extension direction that spans the width direction intersecting the extension direction. [Brief explanation of the drawing]

[0006] [Figure 1] A cross-sectional view showing a part of the configuration of an inkjet head according to the first embodiment. [Figure 2] A cross-sectional view showing a part of the components of the inkjet head. [Figure 3] A plan view showing the configuration of the flow path section of the inkjet head. [Figure 4] Cross-sectional view of the first flow channel substrate of the inkjet head. [Figure 5] Cross-sectional view of the second flow channel substrate of the inkjet head. [Figure 6] A cross-sectional view showing a part of the configuration of an inkjet head according to another embodiment. [Figure 7] A plan view showing the configuration of the flow path section of the inkjet head. [Figure 8] A cross-sectional view showing the configuration of the second flow channel substrate of the inkjet head. [Figure 9] A cross-sectional view showing the configuration of a second flow channel substrate of an inkjet head according to another embodiment. [Figure 10] A cross-sectional view showing a part of the configuration of an inkjet head according to another embodiment. [Modes for carrying out the invention]

[0007] The inkjet head 1, which is a liquid ejection head according to the first embodiment, will be described below with reference to Figures 1 to 5. Figure 1 is a cross-sectional view showing a part of the configuration of the inkjet head according to the first embodiment, and Figure 2 is a cross-sectional view showing a part of the configuration of the inkjet head. Figure 3 is a plan view showing the configuration of the flow channel section of the inkjet head, Figure 4 is a cross-sectional view showing the configuration of the first flow channel substrate, and Figure 5 is a cross-sectional view of the second flow channel substrate. In the figures, arrows X, Y, and Z indicate three mutually orthogonal directions, respectively. In this embodiment, X is along the parallel direction of the nozzle 51 and pressure chamber 31, Y is along the extension direction, and Z is along the axial direction of the nozzle. In each figure, the configuration is enlarged, reduced, or omitted as appropriate for explanatory purposes.

[0008] As shown in Figures 1 and 2, the inkjet head 1 comprises an actuator section 20, a diaphragm 30, a manifold 40 as a flow channel section having a plurality of flow channel substrates 401, 402, a nozzle plate 50 as a nozzle section having a plurality of nozzles 51, and a frame section 45 as a structural section. As an example, in this embodiment, the inkjet head 1 shows an example where the stacking direction of the piezoelectric layer 211, the vibration direction of the piezoelectric element 21, and the vibration direction of the diaphragm 30 are all aligned with the Z direction. In this embodiment, on the back side of the nozzle plate 50, the diaphragm 30 and the manifold 40 form a flow channel structure that forms an ink flow channel 35 within the head 1. The inkjet head 1 is a circulating type that circulates liquid in a predetermined flow channel including a pressure chamber, for example. The inkjet head 1 is installed in a liquid ejection device such as an inkjet recording device.

[0009] The actuator section 20 comprises, for example, a plurality of driving piezoelectric elements 21 and a plurality of non-driving piezoelectric elements 22, which are made of piezoelectric material and arranged alternately along the row direction, and a piezoelectric structure section 26 that integrally connects these plurality of piezoelectric elements 21 and 22. In this embodiment, a nozzle 51 is provided at the center of the extension direction of the actuator section 20, and the actuator section 20 has a structure that is symmetrical on one side and the other side with respect to the nozzle 51. For example, the actuator section 20 is joined to a rectangular base.

[0010] In the actuator section 20, the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 are arranged in parallel at regular intervals. For example, the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 are all configured as rectangular parallelepiped columns with the same external shape. The actuator section 20 is divided into multiple sections by multiple grooves 23, and the multiple driving piezoelectric elements 21 and non-driving piezoelectric elements 22 are formed in rows at the same pitch.

[0011] For example, the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 are each configured in a rectangular shape, such that, in a plan view from the Z direction which is the axial direction of the nozzle 51, the shorter side is aligned with the row direction of the element row, and the longer side is aligned with the extension direction which is perpendicular to the row direction and the Z direction.

[0012] The driving piezoelectric elements 21 are arranged in the Z-direction at positions facing each of the multiple pressure chambers 31 formed in the manifold 40. For example, the center positions of the driving piezoelectric elements 21 in the row direction and extension direction and the center positions of the pressure chambers 31 in the row direction and extension direction are aligned in the Z-direction.

[0013] The non-driven piezoelectric elements 22 are arranged in the Z direction at positions facing the partition wall portions 42 formed in the manifold 40. For example, the center positions of the non-driven piezoelectric elements 22 in the row direction and extension direction and the center positions of the partition wall portions 42 in the row direction and extension direction are arranged side by side in the Z direction.

[0014] For example, the laminated piezoelectric member constituting the actuator section 20 is formed by laminating and sintering sheet-shaped piezoelectric material. The actuator section 20 is formed by dicing the laminated piezoelectric member from one end face to form grooves 23, thereby forming a plurality of rectangular columnar piezoelectric elements at predetermined intervals. Electrodes and the like are then provided on the formed columnar elements to form a plurality of alternately arranged driving piezoelectric elements 21 and a plurality of non-driving piezoelectric elements 22. The plurality of driving piezoelectric elements 21 and the plurality of non-driving piezoelectric elements 22 are arranged alternately in parallel in the column direction, with the grooves 23 in between.

[0015] The piezoelectric members constituting the drive piezoelectric element 21 and the non-drive piezoelectric element 22 are, for example, laminated piezoelectric bodies. The drive piezoelectric element 21 and the non-drive piezoelectric element 22 include a plurality of laminated piezoelectric layers 211 and internal electrodes 221 and 222 formed on the main surfaces of each piezoelectric layer 211. As an example, the drive piezoelectric element 21 and the non-drive piezoelectric element 22 have the same laminated structure. And the drive piezoelectric element 21 and the non-drive piezoelectric element 22 include external electrodes 223 and 224 formed on the surface.

[0016] The piezoelectric layer 211 is composed of a piezoelectric material such as, for example, a PZT (lead zirconate titanate) - based material or a lead - free KNN (sodium potassium niobate) - based material. The plurality of piezoelectric layers 211 are laminated such that the thickness direction is along the lamination direction. For example, in the present embodiment, the thickness direction and the lamination direction of the piezoelectric layer 211 are arranged along the vibration direction (Z direction).

[0017] The internal electrodes 221 and 222 are conductive films formed in a predetermined shape from a sinterable conductive material such as silver palladium. The internal electrodes 221 and 222 are formed in a predetermined region on the main surface of each piezoelectric layer 211. The internal electrodes 221 and 222 have different polarities. For example, one internal electrode 221 is formed in a region that reaches one end of the piezoelectric layer 211 in the extending direction (Y direction), which is perpendicular to both the column direction (X direction), which is the arrangement direction of the plurality of drive piezoelectric elements 21 and the plurality of non - drive piezoelectric elements 22, and the vibration direction (Z direction), and does not reach the other end of the piezoelectric layer 211. The other internal electrode 222 is formed in a region that does not reach one end of the piezoelectric layer 211 and reaches the other end of the piezoelectric layer 211 in the extending direction. The internal electrodes 221 and 222 are respectively connected to the external electrodes 223 and 224 formed on the side surfaces of the piezoelectric elements 21 and 22.

[0018] Further, the laminated piezoelectric members constituting the drive piezoelectric element 21 and the non-drive piezoelectric element 22 may further include dummy layers on either or both of the ends on the nozzle plate 50 side or the opposite side. For example, the dummy layer is made of the same material as the piezoelectric layer 211, has electrodes only on one side, and does not deform because no electric field is applied. For example, the dummy layer does not function as a piezoelectric body, fixes the actuator portion 20 to the base, or serves as a grinding allowance for grinding to achieve accuracy during or after assembly.

[0019] The external electrodes 223 and 224 are formed on the surfaces of the plurality of drive piezoelectric elements 21 and the plurality of non-drive piezoelectric elements 22, and are configured by collecting the ends of the internal electrodes 221 and 222. For example, the external electrodes 223 and 224 are formed on one end face and the other end face in the extending direction of the piezoelectric layer 211, respectively. The external electrodes 223 and 224 are formed of Ni, Cr, Au, etc. by a known method such as plating or sputtering. The external electrode 223 and the external electrode 224 are different poles. The external electrode 223 and the external electrode 224 are respectively arranged on different side surfaces of the plurality of drive piezoelectric elements 21 and the plurality of non-drive piezoelectric elements 22. Incidentally, the external electrodes 223 and 224 may be routed in different regions of the same side surface portion of the plurality of drive piezoelectric elements 21 and the plurality of non-drive piezoelectric elements 22.

[0020] In this embodiment, as an example, the external electrode 223 is an individual electrode and the external electrode 224 is a common electrode. The external electrode 223 serving as the individual electrode of the plurality of drive piezoelectric elements 21 and the plurality of non-drive piezoelectric elements 22 has its electrode layer divided by the groove 23 and is arranged independently of each other. The external electrode 224 serving as the common electrode has its electrode layers connected to each other on the side surface of the piezoelectric structure portion 26, for example, and is grounded, for example. The external electrodes 223 and 224 are connected to the drive circuit via a wiring film, for example. For example, the individual external electrodes 223 and 224 are connected to the control unit 150 via the drive circuit and are configured to be drive controllable. Incidentally, the arrangement of the common electrode and the individual electrode may be reversed.

[0021] Furthermore, the vibration direction of each piezoelectric element 21, 22 is aligned with the stacking direction, and when an electric field is applied, it is displaced in the d33 direction. Each piezoelectric element 21, 22 consists of 3 to 50 layers, with a thickness of 10 μm to 40 μm, and the product of the thickness and the total number of layers being less than 1000 μm.

[0022] In the inkjet head 1, the driving piezoelectric element 21 vibrates when a voltage is applied to the internal electrodes 221 and 222 via the external electrodes 223 and 224. In this embodiment, the driving piezoelectric element 21 vibrates longitudinally along the stacking direction of the piezoelectric body layer 211. Here, longitudinal vibration refers to, for example, "vibration in the thickness direction defined by the piezoelectric constant d33". The driving piezoelectric element 21 displaces the diaphragm 30 and deforms the pressure chamber 31 due to the longitudinal vibration.

[0023] The diaphragm 30 extends along a plane perpendicular to the Z-direction, which is the vibration direction, and is joined to one side of the piezoelectric layer 211 of the plurality of piezoelectric elements 21, 22 in the direction of vibration, i.e., the side facing the nozzle plate 50. In the Z-direction, which is the vibration direction, the diaphragm 30 faces the plurality of nozzles 51 via the pressure chamber 31. The diaphragm 30 is configured to be deformable, for example. The diaphragm 30 is joined to the driving piezoelectric element 21 and the non-driving piezoelectric element 22 of the actuator unit 20 and the frame unit 45. For example, the diaphragm 30 has a vibration region 301 facing the piezoelectric elements 21, 22 and a support region 302 facing the frame unit 45. The diaphragm 30 is provided between the flow channel substrate 401 and the actuator unit 20 in the direction of vibration. The diaphragm 30 is arranged on top of the plurality of flow channel substrates 401, 402, 403 and constitutes a part of the ink flow channel 35.

[0024] The vibration region 301 is, for example, a flat plate shaped such that its thickness direction is the vibration direction of the piezoelectric layer 211. The diaphragm 30 has a surface direction that extends in the direction of the arrangement of the plurality of driving piezoelectric elements 21 and the plurality of non-driving piezoelectric elements 22. The diaphragm 30 is, for example, a metal plate. The diaphragm 30 has a plurality of vibrating parts that face each pressure chamber 31 and are individually displaceable. The diaphragm 30 is formed by a plurality of vibrating parts being integrally connected.

[0025] For example, the diaphragm 30 is made of nickel or SUS plate, and its thickness along the vibration direction is set to approximately 5 μm to 15 μm. In addition, the vibration region 301 may have folds or steps formed between vibration parts and adjacent parts, or between mutually adjacent vibration parts, so that multiple vibration parts can be easily displaced. The vibration region 301 is deformed by the displacement of the part positioned opposite the driving piezoelectric element 21 due to the extension and compression of the driving piezoelectric element 21. For example, since the diaphragm 30 requires a very thin and complex shape, it is formed by electroforming or the like. The diaphragm 30 is joined to the upper end surface of the actuator part 20 by adhesive or the like.

[0026] The support region 302 is a plate-shaped member positioned between the frame portion 45 and the flow path substrate 401. The diaphragm 30 has a structure in which one side and the other side are symmetrical in the Y direction with respect to the nozzle 51.

[0027] The manifold 40 is joined to one side of the diaphragm 30.

[0028] As shown in Figures 1 to 3, the manifold 40 comprises a plurality of stacked flow path substrates 401, 402, and 403. For example, the manifold 40 comprises a first flow path substrate 401 and a flow path substrate 402, both configured to be the same shape, and a second flow path substrate 403, both stacked together. For example, depending on the viscosity of the ink and the volume to be discharged, a plurality of flow path substrates 401, 402, and 403 having openings or grooves are joined together with the nozzle plate 50 and the diaphragm 30 to form a desired ink flow path 35. The plurality of flow path substrates 401, 402, and 403 are arranged in stacked directions, and the openings or grooves formed in each flow path substrate 401, 402, and 403 constitute a predetermined ink flow path 35, including a pressure chamber 31 communicating with a plurality of nozzles 51, individual liquid chambers 33 communicating with a common chamber 32, and a throttling flow path 34 (resistance flow path). As an example, flow channel substrates 401, 402, and 403 are stacked in order from the diaphragm 30 side, with flow channel substrate 403 positioned opposite the nozzle plate 50.

[0029] The manifold 40 is positioned between the nozzle plate 50 and the diaphragm 30. The manifold 40 is formed by stacking and joining together multiple flow path substrates 401, 402, and 403 to create a predetermined ink flow path 35 (liquid chamber) which has multiple pressure chambers 31, individual liquid chambers 33 communicating with a common chamber 32, and multiple throttling flow paths 34 (throttling sections) extending from the individual liquid chambers 33 to the pressure chambers 31. In other words, the manifold 40, by stacking multiple flow path substrates 401, 402, and 403, constitutes a peripheral wall portion 41 surrounding the ink flow path 35 (liquid chamber) composed of multiple pressure chambers 31, multiple throttling flow paths 34 and individual liquid chambers 33, multiple partition wall portions 42 separating the rows of multiple pressure chambers 31, and side wall portions 43 separating the multiple throttling flow paths 34. For example, the manifold 40 constitutes multiple rows of ink flow paths 35 corresponding to the number of nozzles, but in each figure, only the area of ​​three rows is shown for explanatory purposes.

[0030] The first flow channel substrate, the flow channel substrate 401 shown in Figures 1 to 4, is joined to the diaphragm 30. The flow channel substrate 401 is a plate-shaped member with the same shape as the diaphragm 30, and is made of a metal material including SUS430, or a resin material such as silicon, as an example. The flow channel substrate 401 has a first opening 4011 that forms part of the pressure chamber 31 as the first flow channel section, and a second opening 4012 that constitutes part of the individual liquid chamber 33. For example, the first opening 4011 is located in the center of the extension direction in which the ink flow channel 35 extends, and the second openings 4012 are located at both ends. The openings 4011 and 4012 are configured in a rectangular shape with curved corners. In the direction of arrangement, each of the openings 4011 and 4012 is arranged in multiple rows, a beam-shaped section 461 is formed between adjacent openings 4011 in the direction of arrangement, and a beam-shaped section 462 is formed between adjacent openings 4012 in the direction of arrangement.

[0031] The first flow channel substrate, the flow channel substrate 402, is joined to the flow channel substrate 401. The flow channel substrate 402 is a plate-shaped member having the same shape as the flow channel substrate 401, and is composed of a metal material including SUS430, or a resin material such as silicon, as an example. The flow channel substrate 402 has a first opening 4021 that forms part of the pressure chamber 31 as the first flow channel section, and a second opening 4022 that constitutes part of the individual liquid chamber 33. For example, the first opening 4021 is located in the center of the extension direction in which the ink flow channel 35 extends, and the second openings 4022 are located at both ends. The openings 4021 and 4022 are configured in a rectangular shape with curved corners. In the direction of arrangement, each of the openings 4021 and 4022 is arranged in multiple rows, a beam-shaped section 461 is formed between adjacent openings 4021 in the direction of arrangement, and a beam-shaped section 462 is formed between adjacent openings 4012 in the direction of arrangement.

[0032] As shown in Figures 1 to 3 and Figure 5, the second flow channel substrate, the flow channel substrate 403, is laminated on the flow channel substrate 402 and joined to the flow channel substrate 402. The flow channel substrate 403 is a plate-shaped member having the same external shape as the diaphragm 30, and is made of a metal material including SUS430 as an example, or a resin material such as silicon. Individual flow channels, or throttling channels 34, are formed in the flow channel substrate 403. The flow channel substrate 403 has multiple rows of slit rows 4031 as a second flow channel section, each having multiple slits 4032 aligned in one direction via connecting wall portions 44.

[0033] For example, the row of slits 4031 has a plurality of slits 4032 along the extension direction, and a connecting wall portion 44 that spans the width direction and intersects the extension direction at an intermediate point in the extension direction.

[0034] Multiple slits 4032 form openings that penetrate in the thickness direction. A slit row 4031, in which multiple slits 4032 are arranged in one direction via a connecting wall portion 44, is formed, for example, at both ends in the extension direction from which the ink flow path 35 extends. That is, the flow path substrate 403 is the substrate in which openings are formed over the longest range in the first direction among the multiple flow path substrates 401, 402, and 403. Also, for example, the multiple slits 4032 and the slit row 4031 formed thereon are configured to have a smaller width dimension than the openings 4011, 4012, 4021, and 4022 formed in the other substrates 401 and 402. The thickness of the multiple flow path substrates 401, 402, and 403 is set according to conditions such as resistance and flow rate, but in the example shown in Figure 1, the flow path substrate 403, in which the narrowed flow path 34 with a small cross-sectional area is formed, is configured to be thinner than the other first flow path substrates 401 and 402.

[0035] Each slit 4032 is composed of a rectangular opening and is arranged in multiple rows in the direction of alignment. In the flow channel substrate 403, beam-like portions 463 are formed between adjacent slits 4032 in the direction of alignment.

[0036] In other words, the channel substrate 403 has a row of slits 4031 with a longer opening length in the extension direction than the other channel substrates, channel substrates 401 and 402. For example, the row of slits 4031 of the channel substrate 403 consists of a plurality of slits 4032 that are arranged along the entire length of the ink channel 35 in one direction, and extend from one end to the other in the extension direction (Y direction).

[0037] The thicknesses of the multiple flow channel substrates 401, 402, and 403 are set according to conditions such as resistance and flow rate. In the example shown in Figure 1, the second flow channel substrate 403, which forms the throttling channel 34 with a small cross-sectional area, is configured to be thinner than the first flow channel substrates 401 and 402. For example, the second flow channel substrate 403 is configured to be 20 μm to 100 μm thick. For example, at 300 dpi, the pitch of the parallel arrangement of pressure chambers 31 is 169 μm, and the width Wa of the pressure chamber 31 is about 100 μm to 150 μm. The width Wc of the slit 4031 is smaller than the width Wa of the first and second openings. Therefore, the width Wd of the beam-shaped portion 463 of the flow channel substrate 403 is larger than the width Wb of the beam-shaped portions 461 and 462 of the flow channel substrates 401 and 402. For example, the width of the beam-shaped portion 463 is about 20 μm to 70 μm.

[0038] For example, the multiple slits 4032 that make up the slit row 4031 are configured to have a constant width along their entire length in the extension direction. The width Wa of the pressure chamber 31, the width Wb of the beam-like sections 461 and 462, the width Wc of the slit row 4031, and the width Wd of the beam-like section 463 are width dimensions that intersect in one direction and in the stacking direction. In Figures 4 and 5, the width Wa of the pressure chamber 31, the width Wb of the beam-like sections 461 and 462, the width Wc of the slit 4031, and the width Wd of the beam-like section 463 are width dimensions in the X direction.

[0039] For example, the connecting wall portion 44 is a wall-like member that connects the beam-like portions 463 on both sides of the slit row 4031 in the width direction. In other words, the connecting wall portion 44 partially blocks and divides the slit-shaped opening that is long in one direction of the second flow channel substrate 403.

[0040] The connecting wall portion 44 (wall portion) is formed in an area that overlaps with the first openings 4021 and 4022 of the opposing substrate 402, but does not block the nozzle 51. In this embodiment, the connecting wall portion 44 is formed on one side and the other side of the nozzle 51 within the pressure chamber 31. That is, it is positioned at either the inlet / outlet of the pressure chamber 31, which is the part of the pressure chamber 31 that communicates with the throttling flow path 34, and the nozzle 51. Furthermore, the connecting wall portion 44 does not overlap with the nozzle 51, is located at a predetermined distance or more from the nozzle 51, and is positioned in a location that does not block the nozzle 51. The connecting wall portion 44 is formed, for example, by etching when forming the slit row 4031, excluding the portion that will become the connecting wall portion 44. The connecting wall portion 44 becomes a support member that supports the beam-shaped portion 463 of the flow path substrate 403 by connecting multiple beam-shaped portions 463 together. That is, the flow path substrate 403, which is the second flow path substrate, has the longest flow path formed thereon and also has the connecting wall portion 44 as a reinforcing portion.

[0041] For example, in this embodiment, the multiple slits 4032 that constitute the slit row 4031 are arranged to overlap the openings 4011, 4012, 4021, and 4022 of the other flow channel substrates 401 and 402, and communicate with these openings 4011, 4012, 4021, and 4022.

[0042] In the manifold 40, multiple pressure chambers 31 are formed by the first openings 4011, 4021 of multiple flow path substrates 401, 402, and 403 that are aligned and communicating in the stacking direction, and by slits 4032 of a slit row 4031. The multiple pressure chambers 31 are spaces formed on one side of the vibration region 301 of the diaphragm 30, and each pressure chamber 31 communicates with a nozzle 51 formed on the nozzle plate 50. The pressure chambers 31 are also closed on the opposite side of the nozzle plate 50 by the diaphragm 30.

[0043] Multiple pressure chambers 31 communicate with a common chamber 32 via an opening 303 through a throttling channel 34 and individual liquid chambers 33. The pressure chambers 31 hold the liquid supplied from the common chamber 32 and are deformed by the vibration of a vibrating plate 30 that forms part of the pressure chamber 31, thereby discharging the liquid from the nozzle 51.

[0044] In the manifold 40, the second openings 4012, 4022 of the multiple flow channel substrates 401, 402, 403 which are aligned and communicating in the stacking direction, and the slits 4032 of a portion of the slit row 4031, constitute the individual liquid chambers 33 on both sides of the pressure chamber in the Y direction.

[0045] The individual liquid chambers 33 are flow paths that communicate with the ends of the multiple throttling flow paths 34 in the flow direction. The individual liquid chambers 33 are formed, for example, between the diaphragm 30 and the nozzle plate 50 and communicate with the common chamber 32 of the frame portion 45. Here, each flow path substrate 401, 402, and 403 has a structure that is symmetrical on one side and the other side in the Y direction with respect to the nozzle 51, and the flow path length and the flow path cross-sectional shape perpendicular to the Y direction of the individual liquid chambers 33 arranged on both sides in the Y direction with respect to the central pressure chamber 31 are configured to be the same.

[0046] Furthermore, in the manifold 40, a throttling channel 34 is formed by some of the slits 4032 in the row of slits 4031 of the flow channel substrate 403. The throttling channel 34 connects each pressure chamber 31 with the individual liquid chambers 33 and extends in the Y direction, which is the flow direction. The throttling channels 34 on both sides are configured to have a smaller width dimension perpendicular to the extension direction, which is the flow direction, than the individual liquid chambers 33 and the pressure chambers 31, resulting in a narrower cross-section of the channel.

[0047] Here, each flow path substrate 401, 402, and 403 has a structure that is symmetrical on one side and the other side in the Y direction with respect to the nozzle 51, and the flow path length and the flow path cross-sectional shape perpendicular to the Y direction of the throttling flow paths 34 arranged on both sides in the Y direction with respect to the central pressure chamber 31 are configured to be the same. In addition, in the manifold 40, the beam-shaped portion 461 of the stacked flow path substrates 401 and 402, and the central portion of the beam-shaped portion 463 of the flow path substrate 403 form a partition wall portion 42 that separates the multiple pressure chambers 31.

[0048] The partition wall 42 is a wall-like member that separates the multiple pressure chambers 31 in the parallel direction. The partition wall 42 is positioned opposite the non-driven piezoelectric element 22 via the diaphragm 30 and is supported by the non-driven piezoelectric element 22. Multiple partition wall sections 42 are provided at the same pitch as the parallel pitch of the multiple pressure chambers 31.

[0049] In the manifold 40, the beam-shaped portion 463 of the flow path substrate 403 forms a side wall portion 43 that separates the multiple throttling flow paths 34.

[0050] The side wall portion 43 is a wall-like member that separates the multiple throttling passages 34 in the parallel direction. For example, the side wall portion 43 is provided in communication with both sides of the pressure chamber 31. The side wall portion 43 is configured such that the flow resistance of the throttling passage 34 is greater than that inside the pressure chamber 31, and the flow cross-sectional area of ​​the throttling passage 34 is smaller than that inside the pressure chamber 31. Multiple side wall portions 43 are provided at the same pitch as the parallel pitch of the multiple pressure chambers 31.

[0051] The nozzle plate 50 is constructed as a rectangular plate with a thickness of approximately 10 μm to 100 μm, made of a metal such as SUS or Ni, or a resin material such as polyimide. The nozzle plate 50 is positioned on one side of the manifold 40 so as to cover the opening on one side of the pressure chamber 31. The nozzle plate 50 has a plurality of nozzles 51 for discharging droplets. The plurality of nozzles 51 are holes that penetrate the nozzle plate 50 in the thickness direction. The nozzles 51 are arranged in a plurality in the same first direction as the direction in which the pressure chambers 31 are arranged, forming a nozzle row. Each nozzle 51 is provided at a position corresponding to the plurality of pressure chambers 31.

[0052] The frame portion 45 is a structure that is joined to the diaphragm 30 together with the piezoelectric elements 21 and 22. The frame portion 45 is provided on the side of the piezoelectric elements 21 and 22, the diaphragm 30, and the manifold 40, and in this embodiment, for example, it is arranged adjacent to the actuator portion 20. The frame portion 45 constitutes the outer casing of the inkjet head 1. The frame portion 45 may also have a liquid flow path formed inside. In this embodiment, the frame portion 45 is joined to the other side of the diaphragm 30 and forms a common chamber 32 between it and the diaphragm 30.

[0053] The common chamber 32 is formed inside the frame section 45 and communicates with the pressure chamber 31 through an opening 303 provided in the diaphragm 30, an individual liquid chamber 33, and a throttling channel 34.

[0054] In the inkjet head 1 configured as described above, an ink flow path 35 is formed by the nozzle plate 50, the frame portion 45, the manifold 40, and the diaphragm 30. This flow path has multiple pressure chambers 31 communicating with the nozzle 51, individual flow paths composed of a throttling flow path 34 and individual liquid chambers 33 communicating with the multiple pressure chambers 31, and a common chamber 32 which serves as a common flow path. For example, the common chamber 32 communicates with the cartridge, and ink is supplied to each pressure chamber 31 through the common chamber 32. All piezoelectric elements 21 are connected by wiring so that voltage can be applied. In the inkjet head 1, when the control unit 150 applies a driving voltage to the electrodes 221 and 222 using a driver IC, the piezoelectric elements 21 to be driven vibrate in the stacking direction, that is, in the thickness direction of each piezoelectric layer 211. In other words, the piezoelectric elements 21 vibrate longitudinally.

[0055] Specifically, the control unit 150 applies a drive voltage to the internal electrodes 221 and 222 of the piezoelectric element 21 to be driven, thereby selectively driving the piezoelectric element 21. By combining the tensile and compressive deformations of the piezoelectric element 21, the control unit 150 deforms the diaphragm 30, changing the volume of the pressure chamber 31, thereby drawing liquid from the common chamber 32 and discharging it from the nozzle 51.

[0056] Here, the driving operation for driving the inkjet head 1 will be described. The inkjet head 1 according to this embodiment includes piezoelectric elements 21 arranged opposite to the pressure chamber 31, and these piezoelectric elements 21 are connected by wiring so that a voltage can be applied. The control unit 150 sends a drive signal to the driver IC using an image signal corresponding to the image data, and applies a drive voltage to the internal electrodes 221 and 222 of the piezoelectric element 21 to be driven, thereby selectively deforming the piezoelectric element 21. Then, by combining the deformation of the diaphragm 30 in the tensile direction and the deformation in the compressive direction, the volume of the pressure chamber 31 is changed, and liquid is discharged.

[0057] For example, the control unit 150 alternately performs pulling and compressing operations. In the inkjet head 1, when pulling to increase the internal volume of the target pressure chamber 31, the target piezoelectric element 21 is contracted, while the non-target piezoelectric elements are not deformed. Also, in the inkjet head 1, when compressing to decrease the internal volume of the target pressure chamber 31, the target piezoelectric element 21 is extended, while the non-target piezoelectric elements 22 are not deformed.

[0058] According to the inkjet head 1 of the embodiment described above, by stacking multiple flow channel substrates 401, 402, and 403 and providing connecting wall portions 44 at predetermined locations in the slit row 4031 that constitutes a long flow channel, the strength can be improved, thereby improving the handling of the flow channel substrate 403, leading to improved accuracy and yield improvement. Specifically, the slit row 4031, which is the second flow channel portion that constitutes the narrow constricted flow channel 34, forms an opening over its longest range, making it difficult to ensure strength. However, by providing a connecting wall portion 44 in the flow channel substrate 403 at a position opposite to the opening 4021 of another substrate 402, which blocks a part of the extension direction, it is easier to ensure the strength of the beam-shaped member and maintain a fine flow channel shape. Therefore, deformation of the flow channel substrate during cleaning, etc., can be prevented. Furthermore, in a circulating system in which flow channels are formed on both sides of the pressure chamber and ink circulates, the slits become even more elongated, but by providing the connecting wall portion 44, it is easier to ensure the strength of the beam-shaped member and maintain a fine flow channel shape.

[0059] By providing a connecting wall portion 44 that partially closes off, it is easier to connect the elongated beam-shaped members to ensure the strength of the beam-shaped portion 463 and maintain a fine flow path shape. In other words, by partially connecting and supporting the multiple beam-shaped portions 463, the length between the support portions of the beam-shaped portions 463 can be substantially shortened. Therefore, deformation of the flow path substrate 403 during cleaning, etc., can be prevented. As a result, the accuracy of the width dimension of the elongated throttling flow path 34, which particularly affects flow path resistance, can be improved, and discharge performance can also be improved.

[0060] Furthermore, the rigidity of the flow channel section can be increased. For example, if thin SUS plates are used as the flow channel substrates 401, 402, and 403, chemical resistance and ink resistance can be ensured. On the other hand, if silicon is used as the material for the flow channel substrates 401, 402, and 403, dry etching can be performed, allowing for the formation of highly precise flow channels.

[0061] It should be noted that the present invention is not limited to the embodiments described above, and the components can be modified and implemented in practice without departing from the spirit of the invention.

[0062] For example, the location where the connecting wall portion 44 is formed is not limited to the above embodiment and can be changed as appropriate. For example, in the above embodiment, an example was shown where it is provided only in the portion facing the first opening, but it is not limited to this. For example, in another embodiment, the second flow channel substrate 403A of the inkjet head 1A shown in Figures 6 to 8 has an additional connecting wall portion 44 provided at a position facing the second openings 4012 and 4022. The other configurations are the same as those of the inkjet head 1 and flow channel substrate 403 described above. In this case as well, strength can be ensured without obstructing the flow channel.

[0063] Furthermore, the shape of each channel substrate is not limited to the above embodiment. For example, the slit row 4031 may have a configuration in which the width of a part other than the part that constitutes the diaphragm channel 34 is widened. For example, in another embodiment, the channel substrate 403B of the inkjet head 1B shown in Figure 9 has each slit 4032 of the slit row 4031 configured such that the part facing the first openings 4011, 4021 and the second openings 4012, 4022 is the same shape as the opening and the width dimension is widened. The other configurations are the same as those of the inkjet head 1A and channel substrate 403A. In this case as well, by providing a connecting wall portion 44 at a position facing the first opening 4021 and the second opening 4022 of the slit 4032, strength can be ensured without obstructing the channel.

[0064] For example, the specific configuration of the manifold 40 is not limited to the above. For example, an example formed with three flow path substrates 401, 402, and 403 has been shown, but it may also be two or four or more. Furthermore, the shape of the openings in each flow path substrate 401 and 402 is not limited to the above embodiment.

[0065] For example, in the above embodiment, the second openings 4012 and 4022 were shown to form individual liquid chambers 33, but the embodiment is not limited to this. For example, some of the second openings 4012 and 4022 may form a common liquid chamber.

[0066] Furthermore, the positions of the first flow channel substrates 401 and 402 and the second flow channel substrate 403 in the stacking direction are not limited to the above embodiment and can be changed as appropriate. For example, the first flow channel substrates, 401 and 402, may be on the nozzle plate 50 side, and the second flow channel substrate, 403, may be on the actuator section 20 side.

[0067] For example, in the above embodiment, multiple layers of piezoelectric members are stacked and the piezoelectric element 21 is driven using longitudinal vibration (d33) in the stacking direction, but the invention is not limited to this. For example, it can also be applied to a configuration in which the piezoelectric element 21 is composed of a single layer of piezoelectric member, or to a configuration in which it is driven by transverse vibration (d31).

[0068] Furthermore, the specific configuration of the piezoelectric elements 21 and 22, the shape of the flow path, and the configuration and positional relationships of various components including the manifold 40, nozzle plate 50, and frame section 45 are not limited to the examples described above and can be changed as appropriate. Also, the arrangement of the nozzles 51 and pressure chambers 31 is not limited to the above. For example, two or more rows of nozzles 51 may be arranged. Also, dummy chambers may be formed between multiple pressure chambers 31.

[0069] Furthermore, although the above embodiment was described using a circulating system in which flow channels are formed on both sides of the pressure chamber and flow from one side to the other, it is not limited to this. For example, as in the inkjet head 1C shown in Figure 10, it may be a non-circulating system, or it can also be applied to a configuration in which a flow channel is formed on one side of the pressure chamber 31. Also, although Figure 10 shows an example in which one connecting wall portion 44 is arranged on one side of one pressure chamber 31, it is not limited to this, and multiple connecting wall portions 44 may be arranged for one pressure chamber 31, such as arranging connecting wall portions 44 on both sides of the nozzle 51.

[0070] Furthermore, the liquid to be dispensed is not limited to printing ink; for example, it could be a device that dispenses a liquid containing conductive particles for forming wiring patterns on a printed circuit board.

[0071] Furthermore, although the above embodiment shows an example of the inkjet head 1 being used in a liquid ejection device such as an inkjet recording device, it is not limited to this, and can also be used in 3D printers, industrial manufacturing machinery, and medical applications, enabling miniaturization, weight reduction, and cost reduction.

[0072] According to at least one embodiment described above, the desired flow path shape can be easily set.

[0073] In addition, several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0074] 1, 1A, 1B, 1C…Inkjet head, 20…Actuator section, 21…Driven piezoelectric element (piezoelectric element), 22…Non-driven piezoelectric element (piezoelectric element), 23…Groove, 26…Piezoelectric structure section, 30…Vibrating plate, 31…Pressure chamber, 32…Common chamber, 33…Individual liquid chamber (liquid chamber), 34…Aperture channel, 35…Ink channel, 40…Manifold (channel section), 41…Peripheral wall section, 42…Partition wall section, 43…Side wall section, 44…Connecting wall section, 45…Frame section, 50… Nozzle plate, 51...nozzle, 150...control unit, 211...piezoelectric layer, 221...internal electrode, 222...internal electrode, 223...external electrode, 224...external electrode, 301...vibration region, 302...support region, 303...opening, 401...flow channel substrate, 402...flow channel substrate, 403...flow channel substrate, 4011...opening, 4012...opening, 4021...opening, 4022...opening, 4031...slit row, 4032...slit, d33...piezoelectric constant.

Claims

1. A nozzle plate having multiple nozzles for dispensing droplets, A first channel substrate having a first channel section that communicates with the nozzle, The device comprises a second channel substrate on which a second channel section communicating with the first channel section is formed, The second channel portion of the second channel substrate has a connecting wall portion in the middle of the extension direction that extends in the width direction intersecting the extension direction. Liquid dispensing head.

2. The first flow path section has one or more openings that constitute a pressure chamber or a liquid chamber communicating with the pressure chamber, The second flow channel is a row of slits having a plurality of slits along the extension direction, and is in communication with the opening of the first flow channel, The slit has a width dimension perpendicular to the extension direction that is smaller than the opening. The liquid discharge head according to claim 1, wherein the connecting wall portion is positioned opposite the opening of the first flow path substrate.

3. The first flow channel substrate has a first opening that constitutes a pressure chamber and a second opening that constitutes a liquid chamber communicating with the pressure chamber. The liquid discharge head according to claim 1, wherein the connecting wall portion is positioned opposite the first opening or the second opening of the first flow path substrate.

4. The liquid discharge head according to claim 1, wherein the second flow channel substrate is positioned opposite the nozzle plate.

5. The liquid discharge head according to claim 2, which is a circulating type that circulates liquid in a flow path including a pressure chamber communicating with the nozzle.

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