Liquid dispensing head

Abstract

Provided is a liquid ejection head capable of improving ejection performance. 【Solution means】A liquid ejection head according to one embodiment includes a nozzle plate formed with a plurality of nozzles for ejecting droplets, and a flow path portion forming a flow path including a pressure chamber communicating with the nozzles and a resistance flow path narrower than the pressure chamber. The flow path portion includes a first flow path substrate formed with an opening defining the length of the resistance flow path, and a second flow path substrate laminated on the first flow path substrate, having a predetermined width narrower than the opening and configured such that a length dimension along an extension direction is larger than a width dimension intersecting the extension direction, and formed with a slit defining the width of the resistance flow path.

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 made 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, the accuracy of the fluid resistance portion affects the performance. For example, if the cross-sectional area of the flow path is too large, the meniscus vibration of the nozzle portion after ejection becomes large, and if it is too small, the ink refill becomes slow, both of which are factors that hinder high-speed followability. Further, in the case of a circulation type, if the fluid resistance between the upstream and downstream varies, the negative pressure in the pressure chamber varies, which causes a decrease in ejection performance.

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 ejection performance.

Means for Solving the Problems

[0005] A liquid discharge head according to one embodiment comprises a nozzle plate on which a plurality of nozzles for discharging droplets are formed, and a flow path section which forms a flow path including a pressure chamber communicating with the nozzles and a resistance flow path narrower than the width of the pressure chamber, wherein the flow path section comprises a first flow path substrate having an opening that defines the length of the resistance flow path, and a second flow path substrate laminated on the first flow path substrate, having a predetermined width narrower than the opening, and having a length dimension along the extension direction greater than the width dimension intersecting the extension direction, and having a slit that defines the width of the resistance flow path. [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. [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, and 403, 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 material constituting the driving piezoelectric element 21 and the non-driving piezoelectric element 22 is, for example, a laminated piezoelectric body. The driving piezoelectric element 21 and the non-driving piezoelectric element 22 comprise a plurality of laminated piezoelectric layers 211 and internal electrodes 221 and 222 formed on the main surface of each piezoelectric layer 211. For example, the driving piezoelectric element 21 and the non-driving piezoelectric element 22 have the same laminated structure. The driving piezoelectric element 21 and the non-driving piezoelectric element 22 also have external electrodes 223 and 224 formed on their surfaces.

[0016] The piezoelectric layer 211 is composed of a piezoelectric material such as PZT (lead zirconate titanate) or lead-free KNN (potassium sodium niobate). Multiple piezoelectric layers 211 are stacked with their thickness direction aligned with the stacking direction. For example, in this embodiment, the thickness direction and stacking 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 predetermined regions on the main surface of each piezoelectric layer 211. The internal electrodes 221 and 222 are opposite poles. For example, one internal electrode 221 is formed in a region that reaches one end of the piezoelectric layer 211 but not the other end of the piezoelectric layer 211 in the extension direction (Y direction), which is perpendicular to both the column direction (X direction) and the vibration direction (Z direction) of the multiple driving piezoelectric elements 21 and multiple non-driving piezoelectric elements 22. The other internal electrode 222 is formed in a region that does not reach one end of the piezoelectric layer 211 but reaches the other end of the piezoelectric layer 211 in the extension direction. The internal electrodes 221 and 222 are connected to external electrodes 223 and 224 formed on the sides of the piezoelectric elements 21 and 22, respectively.

[0018] In addition, 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 nozzle plate 50 side or the opposite end. 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 unit 20 to the base, or serves as a polishing allowance for polishing 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 faces of the plurality of drive piezoelectric elements 21 and the plurality of non-drive piezoelectric elements 22. Note that the external electrodes 223 and 224 may be routed in different regions on the same side face 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 for 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 layer connected to each other, for example, on the side surface of the piezoelectric structure portion 26 and is grounded, for example. The external electrodes 223 and 224 are connected to the drive circuit via, for example, a wiring film. 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. Note that the arrangement of the common electrode and the individual electrode may be reversed.

[0021] Further, the vibration directions of the piezoelectric elements 21 and 22 are along the stacking direction, and by applying an electric field, they are displaced in the d33 direction. Each of the piezoelectric elements 21 and 22 has a piezoelectric layer 211. Each of the piezoelectric elements 21 and 22 has 3 or more and 50 or less layers, the thickness of each layer is 10 μm or more and 40 μm or less, and the product of the thickness and the total number of stacked layers is 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 through the external electrodes 223 and 224. In the present embodiment, the driving piezoelectric element 21 vibrates longitudinally along the stacking direction of the piezoelectric layer 211. The longitudinal vibration mentioned here is, 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 by longitudinal vibration.

[0023] The diaphragm 30 extends along a plane orthogonal to the Z direction which is the vibration direction, and is joined to one side of the vibration direction of the piezoelectric layers 211 of the plurality of piezoelectric elements 21 and 22, that is, the surface on the nozzle plate 50 side. In the Z direction which is the vibration direction, the diaphragm 30 faces the plurality of nozzles 51 through 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 and 22 and a support region 302 facing the frame unit 45. The diaphragm 30 is provided between the flow path substrate 401 and the actuator unit 20 in the vibration direction. The diaphragm 30 is arranged to overlap the plurality of flow path substrates 401, 402, and 403 and constitutes a part of the ink flow path 35.

[0024] The vibration region 301 is, for example, a flat plate arranged such that the thickness direction is the vibration direction of the piezoelectric layer 211. The diaphragm 30 extends in the plane direction in the arrangement direction 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 vibration sites facing each pressure chamber 31 and individually displaceable. The plurality of vibration sites of the diaphragm 30 are formed integrally and continuously.

[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 that is symmetrical on one side and the other side 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 form 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, in this embodiment, the manifold 40 constitutes multiple rows of ink flow paths 35 corresponding to the number of nozzles 51. The explanatory diagram of each flow path substrate shows the area of ​​three rows.

[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 having 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, and a second opening 4012 that forms 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, and each has a pair of inner wall surfaces 4011a, 4012a extending in the width direction perpendicular to the extension direction, and a pair of side wall surfaces 4011b, 4012b extending in the extension direction. In the direction of arrangement, each of the openings 4011 and 4012 is arranged in multiple rows, with beam-like sections 461 formed between adjacent openings 4011 in the direction of arrangement, and beam-like sections 462 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 made 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, and a second opening 4022 that forms 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, and each has a pair of inner wall surfaces 4021a and 4022a extending in the width direction perpendicular to the extension direction, and a pair of side wall surfaces 4021b and 4022b extending in the extension direction. In the direction of arrangement, each of the openings 4021 and 4022 is arranged in multiple rows, a beam-like section 461 is formed between adjacent openings 4021 in the direction of arrangement, and a beam-like 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. The flow channel substrate 403 has an elongated slit 4031 which is an opening that constitutes a throttling channel 34, which is an individual channel. The length dimension of the slit 4031 in the extension direction is greater than its width dimension. The slit 4031 has a smaller width dimension than the other openings 4011, 4012, 4021, and 4022, and has the longest extension length in one direction. The slit 4031 forms an opening that penetrates in the thickness direction, and is formed, for example, at both ends in the extension direction from which the ink channel 35 extends.

[0033] The slits 4031 are rectangular openings, and multiple slits are arranged in the direction of alignment, for example, in multiple rows. In the flow channel substrate 403, beam-like portions 463 are formed between adjacent slits 4031 in the direction of alignment. The slits 4031 have a pair of side wall surfaces 4031a that extend in the direction of extension.

[0034] In other words, the channel substrate 403 has a slit 4031 with a longer opening length in the extension direction than the other channel substrates, channel substrates 401 and 402. For example, the slit 4031 of the channel substrate 403 is a slit that spans the entire length of the ink channel 35 in one direction in the channel structure, and extends from one end to the other end of the ink channel 35 in the extension direction (Y direction).

[0035] 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 flow 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-like portion 463 is configured to be larger than the width Wb of the beam-like portions 461 and 462. For example, the width of the slit 4031 is configured to be constant along its 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 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.

[0036] For example, in this embodiment, a portion of the slit 4031 is positioned to overlap the openings 4011, 4012, 4021, and 4022 of the other flow channel substrates 401 and 402, and communicates with these openings 4011, 4012, 4021, and 4022. The height of the diaphragm flow channel 34 is determined by the thickness of the second flow channel substrate 403. The width of the diaphragm flow channel 34 is determined by the width of the third opening, the slit 4031 (slit opening). On the other hand, the length of the diaphragm flow channel 34 is determined by the position and shape of the openings 4021 and 4022 through which the slit 4031 communicates.

[0037] In other words, the width of the flow path cross-section of the throttling flow path 34, which has the greatest influence on flow resistance, is defined by the slit 4031, while its length is defined by the position and outer shape of the openings 4021 and 4022 that communicate with the slit 4031. The inner wall surfaces 4021a and 4022a, which are the end faces in the extension direction of the openings 4021 and 4022, and the side wall surface 4031a of the slit 4031 overlap perpendicularly when viewed from the stacking direction. The shape of the outlet and inlet of the throttling flow path 34, i.e., the portion where the liquid chamber 33 connected to the pressure chamber 31 and the common chamber 32 is continuous with the throttling flow path 34, is formed by the side wall of the slit 4031 and the inner walls of the openings 4021 and 4022 that are aligned in a straight line perpendicular to this side wall. In other words, in the slit 4031, a resistance flow path is formed by the portion facing the wall between the multiple openings 4021 and 4022. Therefore, the length of the throttling flow path 34 is restricted by the length between the pressure chamber 31 and the individual liquid chambers 33, i.e., the distance between the inner wall surfaces 4022a and 4021a.

[0038] In the manifold 40, multiple pressure chambers 31 are formed by the first openings 4011, 4021 and slits 4031 of multiple flow path substrates 401, 402, and 403 that are aligned and communicating in the stacking direction. 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. In addition, the pressure chambers 31 are closed on the opposite side of the nozzle plate 50 by the diaphragm 30.

[0039] 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.

[0040] In the manifold 40, the second openings 4012, 4022 and slits 4031 of a plurality of flow path substrates 401, 402, and 403 that are aligned and communicating in the stacking direction constitute the individual liquid chambers 33 on both sides of the pressure chamber in the Y direction.

[0041] 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.

[0042] Furthermore, in the manifold 40, a throttling channel 34 is formed by the slit 4031 of the flow path 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 one opening 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 the same direction as the arrangement of the pressure chambers 31, forming a nozzle row. Each nozzle 51 is provided at a position corresponding to one of the plurality of pressure chambers 31.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] According to the inkjet head 1 of the embodiment described above, multiple flow channel substrates 401, 402, and 403 are stacked, and in the flow channel section including a pressure chamber 31, an appressor flow channel 34, and a liquid chamber 33, the width of the appressor flow channel 34 is defined by the width of the slit 4031, and the length of the appressor flow channel 34 is restricted by the openings 4021 and 4022 of the other flow channel substrates 402. As a result, the accuracy of the appressor flow channel 34 can be improved and variations can be suppressed.

[0055] For example, when forming a narrow slit and a wide opening in a continuous sequence on a single substrate, it is difficult to accurately achieve the shape of the edge portion where the width changes. For instance, when forming an opening by etching, it is difficult to process the edge of the part where the width narrows with high precision, and the corners where the width changes tend to become rounded. As a result, variations in the flow path shape are likely to occur. In particular, if the flow path substrate is thin, even small variations can have a significant impact, and especially in the case of a circulating system, variations in fluid resistance between the upstream and downstream sections can lead to a decrease in discharge performance due to the difference in negative pressure within the pressure chamber.

[0056] In contrast, according to the above embodiment, the width and length of the resistive flow path are defined by slits and openings formed on different substrates, respectively. This simplifies the shape of the openings and slits on individual substrates 403 and 402, facilitating processing while achieving high precision in the flow path shape. Therefore, the accuracy of the flow path resistance can be improved, variations can be suppressed, and discharge performance can be enhanced.

[0057] 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.

[0058] 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.

[0059] 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. 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.

[0060] 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).

[0061] 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. 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 shown in Figure 6, another embodiment 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.

[0062] 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.

[0063] 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.

[0064] According to at least one embodiment described above, the desired flow path shape can be easily set.

[0065] 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]

[0066] 1...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, 45...Frame section, 50...Nozzle plate, 51...Nozzle, 150...Control section, 211...Piezoelectric layer, 221...Internal electrode, 222...Internal electrode, 223...External electrode, 2 24...External electrode, 301...Vibration region, 302...Support region, 303...Opening, 401...Flow channel substrate, 402...Flow channel substrate, 403...Flow channel substrate, 461...Beam-shaped part, 462...Beam-shaped part, 463...Beam-shaped part, 4011...Opening, 4011a...Inner wall surface, 4011b...Side wall surface, 4012...Opening, 4012a...Inner wall surface, 4012b...Side wall surface, 4021...Opening, 4021a...Inner wall surface, 4021b...Side wall surface, 4022...Opening, 4022a...Inner wall surface, 4022b...Side wall surface, 4031...Slit, 4031a...Side wall surface, d33...Piezoelectric constant.

Claims

1. A nozzle plate having multiple nozzles formed for dispensing droplets, The device comprises a flow path section that forms a flow path including a pressure chamber communicating with the nozzle and a resistance flow path that is narrower than the pressure chamber, The aforementioned flow channel portion includes a first flow channel substrate having an opening that defines the length of the resistive flow channel, A second flow channel substrate is laminated on the first flow channel substrate, has a predetermined width narrower than the opening, and has a length dimension along the extension direction greater than the width dimension intersecting the extension direction, and has a slit formed therein that defines the width of the resistance flow channel, A liquid dispensing head equipped with a liquid dispensing head.

2. The aforementioned flow path section is arranged on top of the nozzle plate, The slit of the second flow channel substrate has a pair of side wall surfaces along the extension direction, The liquid discharge head according to claim 1, wherein the opening of the first flow channel substrate has an inner wall surface extending in a direction intersecting the side wall surface.

3. The first flow path substrate has a plurality of openings that constitute a pressure chamber communicating with the nozzle, or a liquid chamber communicating with the pressure chamber. The slit is positioned so that at least a portion of it overlaps the opening and communicates with the opening. The liquid discharge head according to claim 2, wherein the resistive flow path is formed by the slits in the portion of the first flow path substrate that faces the wall-like portion between the plurality of openings.

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 1, wherein the liquid is circulated in the flow path including the pressure chamber.

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