Liquid ejection head

Abstract

A liquid ejection head capable of ensuring stable ejection characteristics is provided. A liquid ejection head according to one embodiment includes an actuator portion, a nozzle plate, and a throttle portion. The actuator portion has grooves that constitute a plurality of pressure chambers and a plurality of side walls formed between the grooves that constitute the pressure chambers. The nozzle plate is disposed opposite one side of the plurality of pressure chambers. The throttle portion has a throttle wall that blocks a portion of a communication port of the pressure chamber of the actuator portion that communicates with the common chamber and forms a throttle port in which the width of the one side is reduced in the depth direction of the pressure chamber.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejector head. Background Technology

[0002] In recent years, the demand for high productivity in inkjet printheads, leading to demands for higher speeds and larger droplet volumes, has become a key issue. For example, shared-mode, wall-mounted inkjet printheads have become high-powered, designed for ejecting high-viscosity inks and large droplets. In shared-mode, wall-mounted printheads, a so-called three-cycle drive is typically employed, where two pressure chambers share the same drive column, with one-third of the multiple chambers acting as pressure chambers simultaneously. Alternatively, an independent drive head has been developed, using the two sides of the driven pressure chamber as dummy pressure chambers, with two independent drive columns driving each pressure chamber. For example, a structure has been developed where multiple slots are formed in a piezoelectric element, with the inlet and outlet blocked every other slot. The slots without blocked inlets and outlets act as pressure chambers, while the blocked slots act as air chambers, and are driven independently.

[0003] In such an inkjet head, after ink droplets are ejected, ink is replenished from the general liquid chamber to the pressure chamber. At this point, overshoot occurs at the nozzle, causing the meniscus to bulge. The lower the flow path resistance from the general liquid chamber to the nozzle, the greater the overshoot. If this overshoot cannot be contained, ejection cannot occur in a stable meniscus state. Therefore, to achieve high speeds in an inkjet head, it is necessary to quickly contain the meniscus bulge and ensure stable ejection characteristics. Summary of the Invention

[0004] The technical problem that the invention aims to solve

[0005] The technical problem to be solved by the present invention is to provide a liquid ejection head that can ensure stable ejection characteristics.

[0006] Solutions for solving technical problems

[0007] One embodiment of the liquid ejector head includes an actuator section, a nozzle plate, and a throttling section. The actuator section has grooves forming a plurality of pressure chambers and a plurality of sidewalls formed between the grooves forming the pressure chambers. The nozzle plate is disposed opposite to one side of the plurality of pressure chambers. The throttling section has a throttling wall that blocks a portion of the communication port of the actuator, forming a narrowed throttling port on one side in the depth direction of the pressure chamber, the communication port being a communication port of the pressure chamber communicating with the general chamber. Attached Figure Description

[0008] Figure 1 This is a perspective view showing the inkjet head involved in the implementation method.

[0009] Figure 2This is an exploded perspective view showing the structure of a portion of the inkjet head involved in the embodiment.

[0010] Figure 3 It is a three-dimensional view showing an enlarged portion of the structure of the inkjet head.

[0011] Figure 4 It is a cross-sectional view showing an enlarged view of a portion of the structure of the inkjet head.

[0012] Figure 5 It is a cross-sectional view showing an enlarged view of a portion of the structure of the inkjet head.

[0013] Figure 6 This is an explanatory diagram showing the manufacturing method of the inkjet head.

[0014] Figure 7 This is a schematic diagram illustrating an inkjet printer according to the implementation method.

[0015] Explanation of reference numerals in the attached figures

[0016] 10. Inkjet head; 11. Actuator base; 12. Nozzle plate; 13. Frame; 17. Circuit board; 18. Manifold; 21. Substrate; 22. Actuator section; 23. Cover section; 25. Supply port; 26. Discharge port; 27. Ink chamber; 29. ​​Adhesive layer; 31. Pressure chamber; 32. Air chamber; 33. Component wall (wall section); 34. Electrode layer; 51. Thin film; 52. Driver IC; 100. Inkjet printer; 111. Housing; 112. Media supply section; 113. Image forming section; 114. Media discharge section; 115. Conveying device; 116. Control section; 117. Support section; 118. Conveyor belt; 119. Support plate; 120. Belt roller; 121. Guide plate pair; 122. Conveying roller; 130. Head unit; 132. Ink tank; 133. Connecting flow path; 134. Circulating pump; 211. Pattern wiring; 240. Throttling section; 241. Protrusion; 242. Throttling port; 271. First general-purpose chamber; 27. Ink chamber; 272. Second general-purpose chamber; 291. Adhesive. Detailed Implementation

[0017] The following reference Figures 1 to 6 The structure of the inkjet head 10, which is the liquid ejection head according to the first embodiment, will be described. Figure 1 This is a perspective view showing the inkjet head according to the first embodiment. Figure 2 This is an exploded 3D view of a part of the inkjet head. Figure 3 It is a magnified 3D diagram showing a portion of the inkjet head's structure. Figure 4 as well as Figure 5 It is a cross-sectional view showing an enlarged view of a portion of the inkjet head structure. Figure 6 This is an explanatory diagram showing the manufacturing process of the inkjet head. Figure 7 This is a schematic diagram of an inkjet printer that serves as a liquid ejection device. In the diagram, X, Y, and Z represent the first, second, and third mutually orthogonal directions, respectively. Furthermore, in this embodiment, the directions are described based on the orientation of the nozzle 28 of the inkjet head 10, the parallel direction of the pressure chamber 31 along the X-axis, the extension direction of the pressure chamber 31 along the Y-axis, and the liquid ejection direction along the Z-axis, but it is not limited to this.

[0018] Figures 1 to 5 The inkjet head 10 shown is a device for ejecting ink, for example, mounted inside an inkjet printer. The inkjet head 10 is a shared-mode, wall-mounted inkjet head. For example, the inkjet head 10 is an independently driven inkjet head with alternating pressure chambers 31 and air chambers 32. The air chamber 32 is an air chamber that is not supplied with ink and does not have nozzles 28. In this embodiment, the inkjet head 10 is a so-called side-jet type inkjet head.

[0019] The inkjet head 10 includes an actuator base 11, a nozzle plate 12, and a frame 13. The actuator base 11 is an example of a substrate. An ink chamber 27, which is supplied with ink as an example of a liquid, is formed inside the inkjet head 10.

[0020] Furthermore, the inkjet head 10 includes components such as a circuit board 17 for controlling the inkjet head 10 and a manifold 18 that forms part of the path between the inkjet head 10 and the ink can.

[0021] like Figures 2 to 5 As shown, the actuator base 11 includes a substrate 21 and a pair of actuator sections 22.

[0022] The substrate 21 is formed into a rectangular plate shape, for example, from a ceramic such as alumina. The substrate 21 has a flat mounting surface. A pair of actuator portions 22 are joined to the mounting surface of the substrate. A plurality of supply holes 25 and discharge holes 26 are formed on the substrate 21.

[0023] like Figure 2 as well as Figure 3 As shown, a patterned wiring 211 is formed on the substrate 21 of the actuator base 11. The patterned wiring 211 is formed, for example, from a nickel thin film. The patterned wiring 211 has a general pattern and individual patterns, and is configured to a predetermined pattern shape that is connected to the electrode layer 34 formed on the actuator section 22.

[0024] The supply hole 25 is located in the center of the substrate 21 and is arranged side-by-side along the long side of a pair of actuator sections 22. The supply hole 25 communicates with the ink supply section of the manifold 18. The supply hole 25 is connected to the ink tank via the ink supply section. The supply hole 25 supplies ink from the ink tank to the ink chamber 27. Furthermore, the supply hole 25 is not limited to... Figure 2The multiple circular holes shown can also be a single elongated hole along the X direction of the actuator section 22.

[0025] The discharge port 26 is arranged in two rows side by side, separated from the supply port 25 and a pair of actuator sections 22. The discharge port 26 communicates with the ink discharge section of the manifold 18. The discharge port 26 is connected to the ink tank via the ink discharge section. The discharge port 26 discharges ink from the ink chamber 27 to the ink tank.

[0026] A pair of actuator portions 22 are bonded to the mounting surface of the substrate 21. The pair of actuator portions 22 are arranged side-by-side in two rows on the substrate 21, separated by a supply hole 25. Each actuator portion 22 is formed of two plate-shaped piezoelectric bodies, for example, made of lead zirconate titanate (PZT). The two piezoelectric bodies are bonded together with their polarization directions opposing each other in their thickness direction. The actuator portions 22 are bonded to the mounting surface of the substrate 21, for example, using a thermosetting epoxy adhesive. Figure 2 As shown, the actuator section 22 is arranged parallel to the nozzles 28 arranged in two rows within the ink chamber 27. The actuator section 22 divides the ink chamber 27 into a first general-purpose chamber 271 for opening the supply port 25 and two second general-purpose chambers 272 for opening the discharge port 26.

[0027] The width of the actuator section 22 in the short side direction gradually increases from the top portion 222 side towards the substrate side. The cross-sectional shape of the actuator section 22 in the direction orthogonal to the long side direction (short side direction) is formed into a trapezoidal shape. The side portion 221 of the actuator section 22 has an inclined surface that is inclined relative to the second direction and the third direction. The top portion 222 of the actuator section 22 is bonded to the nozzle plate 12 by an adhesive layer 29.

[0028] The actuator section 22 includes multiple pressure chambers 31, multiple air chambers 32, and throttling sections 240 respectively provided at the inlet and outlet of each pressure chamber 31. The actuator section 22 has multiple element walls 33 (side wall portions), and grooves 14 forming the pressure chambers 31 and air chambers 32 are provided between the element walls 33. In other words, the element walls 33 are formed as driving elements between the grooves 14 forming the pressure chambers 31 and air chambers 32.

[0029] like Figures 1 to 5 As shown, the bottom surface of the groove 14 is connected to the main surface of the substrate 21 via an inclined side surface 221. Multiple pressure chambers 31 and multiple air chambers 32 are arranged alternately. The pressure chambers 31 and air chambers 32 extend in directions intersecting the long side direction of the actuator section 22, and multiple pressure chambers 31 and air chambers 32 are arranged side-by-side in the long side direction (X direction) of the actuator section 22. That is, the side-by-side direction of the multiple pressure chambers 31 and air chambers 32 is along the X direction. In this embodiment, for example, the groove 14 is configured such that its width dimension in the X direction is constant in the depth direction along the Z direction, and its cross-section orthogonal to the extension direction, i.e., the Y direction, is rectangular.

[0030] Furthermore, the shape of the pressure chamber 31 may differ from that of the air chamber 32. A component wall 33 is formed between the pressure chamber 31 and the air chamber 32, and deforms according to a drive signal, thereby changing the volume of the pressure chamber 31.

[0031] Electrode layers 34 are respectively provided on the inner wall surfaces of the pressure chamber 31 and the air chamber 32 of the actuator base 11. The electrode layers 34 are formed, for example, of a conductive film such as a nickel thin film. The electrode layers 34 extend from the inner surface of the groove 14 to the substrate 21 and are connected to the pattern wiring 211. For example, the electrode layers 34 are formed at least on the side surface of the element wall 33, that is, on the side wall surface of the groove 14 that constitutes the pressure chamber 31. The electrode layers 34 may also be formed on the side surface and the bottom surface of the pressure chamber 31, for example.

[0032] Multiple pressure chambers 31 communicate with multiple nozzles 28 of a nozzle plate 12 that is joined to the top of the element wall 33. That is, the nozzle plate 12 is arranged opposite to the third-direction upward side of the multiple pressure chambers 31. The two ends of the pressure chambers 31 in the second direction communicate with the ink chambers 27. That is, one end opens into the first general chamber 271 of the ink chamber 27, and the other end opens into the second general chamber 272 of the ink chamber 27. Therefore, ink flows in from one end of the pressure chamber 31 and flows out from the other end. A throttling portion 240 is formed in the communication port of the pressure chamber 31 with the ink chamber 27. The throttling portion 240 has an opening, namely a throttling orifice 242, configured such that the flow resistance is greater than that inside the pressure chamber 31. As an example, in this embodiment, throttling portions 240 are formed at the communication ports at both ends in the extending direction of the pressure chamber 31.

[0033] like Figure 4 as well as Figure 5 As shown, the throttling section 240 is configured to narrow the width of the opening of the pressure chamber 31 communicating with the ink chamber 27 in the X direction. As an example, the throttling section 240 has a pair of protrusions 241 made of photosensitive resin serving as throttling walls, and a tapered slit, i.e., a throttling orifice 242, with a narrowed nozzle plate side width is formed between these pair of protrusions 241. That is, the pair of protrusions 241 form a throttling orifice 242 with a narrowed nozzle plate side width in the depth direction of the pressure chamber 31.

[0034] The end of the protrusion 241 in the second direction of the pressure chamber 31 protrudes from the element wall 33 into the groove 14 and blocks part of the communication port. In this embodiment, a pair of element walls 33 constituting the two sides of the pressure chamber 31 in the X direction (i.e., the element walls 33 on both sides in the X direction) are respectively formed with protrusions 241 made of photosensitive resin.

[0035] For example, the protrusion 241 can be formed either across the entire length of the groove 14 in the depth direction (i.e., the third direction) of the pressure chamber 31, or it can be formed on a portion of the third direction. Additionally, the protrusion 241 can be formed on the bottom surface of the groove 14, in addition to the sides of the groove 14. That is, it can also be a structure where the protrusions 241 on both sides are continuous at the bottom of the groove 14.

[0036] The protrusion 241 is a wall component that increases the flow resistance at the inlet and outlet of the pressure chamber 31 and inhibits the entry of adhesive 291 from the end of the nozzle plate 12 side. For example, the protrusions 241 provided on both sides of each communication port of the pressure chamber 31 have rectangular cross-sections orthogonal to a third direction. Each pair of protrusions 241 is configured as a cone shape in the depth direction, with the protrusion on the top side being greater than the protrusion on the bottom side. That is, the opposing surfaces of the pair of protrusions 241 are inclined such that their top sides approach each other, and the distance between the opposing surfaces gradually widens on the bottom side. The top side of the protrusion 241 refers to the adhesive side with the nozzle plate 12. The bottom side of the protrusion 241 refers to the position where it separates from the adhesive side with the nozzle plate 12.

[0037] The groove 14 constituting the pressure chamber 31 is not completely covered by the protrusion 241. A throttling orifice 242 is formed between a pair of protrusions 241 on both sides, connecting the pressure chamber 31 with the first general chamber 271 and the second general chamber 272. The throttling orifice 242 is a slit shape extending upward in a third direction that is the depth direction of the pressure chamber 31. Its opening width in the first direction is configured to be smaller than the width in the first direction inside the pressure chamber 31, thereby being smaller than the flow path cross-sectional area of ​​the pressure chamber 31.

[0038] Furthermore, the opening width of the opening end 2421 on the nozzle plate 12 side of the throttle orifice 242 is configured to be such that the uncured adhesive 291 can be held in the opening end 2421 by means of surface tension.

[0039] For example, after a photosensitive resin film 244 is formed on the inner walls of the pressure chamber 31 and the air chamber 32, the portion constituting the protrusion 241 is cured by exposure treatment, thereby forming a throttling portion 240. That is, the protrusion 241 blocks part of the connecting port at both ends in the second direction, thereby forming a throttling portion 240 with increased flow resistance.

[0040] Furthermore, when the flow resistance of the throttling section 240 is too high, the ink supply towards the pressure chamber 31 after the ink droplet is ejected slows down, thus hindering high-speed operation. Additionally, the meniscus bulge varies depending on ink viscosity, ejection volume, and drive frequency. Therefore, the shape of the protrusion 241 and the size and position of the throttling orifice 242 are respectively set to achieve flow resistance corresponding to the ink supply conditions and the characteristics of the meniscus bulge. Furthermore, the sizes of the protrusion 241 and the throttling orifice 242 can be any structure that can reduce the opening width of the opening end 2421 on the nozzle plate 12 side of the throttling orifice 242 to suppress the inflow of the adhesive 291; for example, they can be set according to conditions such as the viscosity of the adhesive 291. Moreover, the throttling sections 240 on both sides can also have different structures.

[0041] One third-direction upward side of the air chamber 32 is blocked by the nozzle plate 12 attached to the top. Additionally, both ends of the plurality of air chambers 32 in the second direction are blocked by covers 23 made of photosensitive resin material. That is, covers 23 are respectively disposed between the first general-purpose chamber 271 of the ink chamber 27 and one end of the air chamber 32 in the second direction, between the second general-purpose chamber 272, and between the other end of the air chamber 32 in the second direction and the second general-purpose chamber 272, thereby separating both ends of the air chamber 32 from the ink chamber 27. Therefore, the air chamber 32 constitutes an air chamber in which ink does not flow.

[0042] For example, in the same or different process as forming the protrusion 241, after applying photosensitive resin to both ends of the air chamber 32, the target area is cured to form the cover 23.

[0043] The nozzle plate 12 is formed, for example, from a rectangular film of polyimide. The nozzle plate 12 faces the mounting surface of the actuator base 11. A plurality of nozzles 28 are formed on the nozzle plate 12, extending through the nozzle plate 12 in the thickness direction.

[0044] Multiple nozzles 28 are configured in the same number as pressure chambers 31, each facing one of the pressure chambers 31. Multiple nozzles 28 are arranged side-by-side along a first direction, forming two rows corresponding to a pair of actuator sections 22. Each nozzle 28 is configured as a cylindrical shape extending along a third direction. For example, the diameter of the nozzle 28 can be constant, or it can be a shape that tapers towards the center or the top. Each nozzle 28 is positioned opposite the middle portion of the pressure chamber 31 formed in the extending direction of the pair of actuator sections 22, and communicates with the pressure chamber 31. One nozzle 28 is positioned at a corresponding position between the two ends of each pressure chamber 31, for example, at the center of the long side.

[0045] The frame 13 is, for example, formed into a rectangular frame shape from a nickel alloy. The frame 13 is located between the mounting surface of the actuator base 11 and the nozzle plate 12. The frame 13 is bonded to both the mounting surface of the actuator base 11 and the nozzle plate 12. That is, the nozzle plate 12 is mounted on the actuator base 11 through the frame 13.

[0046] The manifold 18 is connected to the side of the actuator base 11 opposite to the nozzle plate 12. Inside the manifold 18, there is an ink supply section that serves as a flow path communicating with the supply port 25 and an ink discharge section that serves as a flow path communicating with the discharge port 26.

[0047] The circuit board 17 is a thin-film carrier package (FCP). The circuit board 17 has: a resin film 51 with multiple wirings and is flexible; and a driver IC 52 connected to the multiple wirings of the film 51. The driver IC 52 is electrically connected to the electrode layer 34 through the wirings and pattern wiring 211 of the film 51.

[0048] Inside the inkjet head 10 configured as described above, an ink chamber 27 is formed, surrounded by an actuator base 11, a nozzle plate 12, and a frame 13. That is, the ink chamber 27 is formed between the actuator base 11 and the nozzle plate 12. For example, the ink chamber 27 is divided into three sections in the second direction by two actuator sections 22, having two second general-purpose chambers 272 that serve as general-purpose chambers for opening to the discharge port 26, and a first general-purpose chamber 271 that serves as a general-purpose chamber for opening to the supply port 25. The first general-purpose chamber 271 and the second general-purpose chamber 272 communicate with a plurality of pressure chambers 31.

[0049] In the inkjet head 10 configured as described above, ink circulates between the ink tank and the ink chamber 27 through the supply port, pressure chamber, and discharge port. For example, based on a signal input from the control unit of the inkjet printer, the drive IC 52 applies a drive voltage to the electrode layer 34 of the pressure chamber 31 through the wiring of the thin film 51, thereby generating a potential difference between the electrode layer 34 of the pressure chamber 31 and the electrode layer 34 of the air chamber 32, thereby selectively causing the element wall 33 to undergo shared-mode deformation. By deforming the element wall 33 formed between the pressure chamber 31 and the air chamber 32 according to the drive signal, the volume of the pressure chamber 31 changes.

[0050] By deforming the element wall 33 in a shared mode, the volume of the pressure chamber 31, where the electrode layer 34 is located, increases and the pressure decreases. As a result, ink from the ink chamber 27 flows into the pressure chamber 31.

[0051] With the volume of pressure chamber 31 increasing, drive IC 52 applies a reverse potential drive voltage to the electrode layer 34 of pressure chamber 31. This causes the element wall 33 to undergo shared-mode deformation, reducing the volume of pressure chamber 31 where the electrode layer 34 is located and increasing the pressure. Consequently, the ink in pressure chamber 31 is pressurized and ejected from nozzle 28.

[0052] As a method for manufacturing the inkjet head 10, firstly, a piezoelectric component forming multiple grooves 14 is glued onto a plate-shaped substrate 21 using an adhesive or the like, and then a mechanical processing method using a cutting saw, slicing machine, or the like is used to form an actuator base 11 with a predetermined shape. Alternatively, for example, multiple actuator bases 11 of predetermined shapes can be manufactured by pre-forming multiple block-shaped base components of multiple thicknesses and then dividing them.

[0053] Next, an electrode layer 34 and a pattern wiring 211 are formed on the inner surface of the groove 14 that constitutes the pressure chamber 31 and the air chamber 32, and on the surface of the substrate 21. Through the above, an electrode layer 34 and a pattern wiring 211 are formed at predetermined locations on the surface of the actuator base 11.

[0054] Next, a throttling section 240 is formed at the end of the pressure chamber 31, where the flow resistance is greater than that inside the pressure chamber 31. For example, the method for forming the throttling section 240 includes: a film-forming process, in which a photosensitive resin film 244 of a photosensitive resin is formed in the groove 14 constituting the pressure chamber 31; and a molding process, in which the photosensitive resin film 244 is molded by exposure and development.

[0055] As a film-forming treatment, firstly as Figure 6 As shown in Act 11, a photosensitive resin film 244 is formed by coating the inner wall of the pressure chamber 31 with a photosensitive resin. At this time, the shape of the photosensitive resin on the exposure surface is made concave by controlling the amount of photosensitive resin applied. The top surface 2440 of the photosensitive resin film 244 in each groove 14 is formed as a concave surface that is recessed from the center to the bottom.

[0056] Next, as a molding process, the photosensitive resin films 244 at both ends of the pressure chamber 31 are molded by exposure and development. For example, in this embodiment, as an example, after the conical curing region 2441 is cured by exposure of the concave surface 2440, a development process is performed to remove the uncured region 2442, thereby forming the conical protrusion 241 and the throttle orifice 242. Furthermore, during the molding process, a baking process can be performed at a necessary time.

[0057] For example, as an exposure process, as shown in Act 11, an exposure mask 245 is disposed on the top side of the element wall 33, and exposure is performed from the top side through the exposure mask 245, thereby exposing to a depth reaching the bottom of the groove 14. For example, the exposure mask 245 has a pattern shape having a non-exposure portion 2451 corresponding to the size of the top side of the throttle orifice 242. As an example, by setting the exposure direction to the depth direction of the pressure chamber 31, the protrusions 241 on both sides can be exposed simultaneously to form the film. At this time, since the surface 2440 of the top side of the photosensitive resin film 244 where the exposure light is incident is concave, if the ultraviolet light used as the exposure light is incident from the top side parallel to the Z direction, it travels in the direction of light dispersion, thus forming an uncured area that widens into a cone shape towards the bottom. That is, since the incident surface 2440 is concave, the boundary between the cured area 2441 and the uncured area 2442 becomes an inclined shape that widens towards the bottom side.

[0058] Then, by rinsing the unwanted unexposed resin with a developing solution, as shown in Act 13, a cone-shaped protrusion 241 formed by a photosensitive resin film 244 is formed at the inlet and outlet of the pressure chamber 31, and a throttling orifice 242 that is narrow at the top and widens towards the bottom is formed between the protrusions 241 on both sides, thereby forming a throttling section 240.

[0059] Furthermore, during the film-forming process of the throttling section 240 and the molding process based on exposure and development, the film-forming process of coating the two ends of the air chamber 32 with the photosensitive resin and the molding process based on exposure and development can be performed simultaneously, thereby forming the cover 23 that blocks the air chamber 32 at the same time as the throttling section 240. Alternatively, the cover 23 can also be formed by other processes before or after the formation of the throttling section 240.

[0060] Then, the actuator base 11 is assembled to the manifold 18, and the frame 13 is glued to one side of the substrate 21 of the actuator base 11 using a thermoplastic resin adhesive sheet.

[0061] Then, grinding is performed to make the top of the assembled frame 13, the component wall 33 of the actuator section 22, and the nozzle plate 12 side of the protrusion 241 the same surface. Then, the nozzle plate 12 is bonded and installed on the top of the component wall 33, the frame 13, and the ground surface of the protrusion 241. For example, adhesive 291 is applied to the surface of the nozzle plate 12 opposite to the pressure chamber 31 to form an adhesive layer 29. After positioning and bonding in a manner opposite to the nozzle 28, the adhesive 291 is cured to form a bond. At this time, the throttle orifice 242 on the nozzle plate 12 side is configured to be narrow, so that the adhesive 291 before curing can be prevented from entering the interior from the throttle orifice 242. Through the above, the nozzle plate 12 is bonded to the actuator section 22, and an adhesive layer 29 is provided between the component wall 33 and the nozzle plate 12. Moreover, as Figure 1 As shown, the inkjet head 10 is completed by connecting the driver IC 52 and the circuit board 17 on the pattern wiring 211 formed on the main surface of the substrate 21 via a flexible printed circuit board.

[0062] The following reference Figure 7 An example of an inkjet printer 100 equipped with an inkjet head 10 will be described. The inkjet printer 100 includes a housing 111, a media supply unit 112, an image forming unit 113, a media discharge unit 114, a transport device 115, and a control unit 116.

[0063] The inkjet printer 100 is a liquid ejection device that ejects liquid such as ink along a predetermined transport path A from the media supply unit 112 through the image forming unit 113 to the media discharge unit 114, thereby performing image forming processing on the paper P by transporting a recording medium such as paper P, which is the object to be ejected.

[0064] The housing 111 forms the outer contour of the inkjet printer 100. A discharge port for discharging paper P to the outside is provided at a predetermined position on the housing 111.

[0065] The media supply unit 112 has multiple paper feed boxes, which are configured to stack and hold multiple sheets of paper P of various sizes.

[0066] The media discharge section 114 has a paper discharge tray configured to hold the paper P discharged from the discharge port.

[0067] The image forming unit 113 includes a support portion 117 for supporting the paper P and a plurality of head units 130 disposed opposite each other above the support portion 117.

[0068] The support 117 includes: a conveyor belt 118 arranged in a ring in a predetermined area for image formation; a support plate 119 supporting the conveyor belt 118 from the rear side; and a plurality of belt rollers 120 arranged on the rear side of the conveyor belt 118.

[0069] During image formation, the support 117 supports the paper P on the holding surface, which is the upper surface of the conveyor belt 118, and the paper P is conveyed towards the downstream side by the rotation of the belt roller 120 at a predetermined time.

[0070] The printhead unit 130 includes multiple (four colors) inkjet heads 10, ink tanks 132 mounted on each inkjet head 10 as liquid reservoirs, a connecting flow path 133 connecting the inkjet head 10 and the ink tank 132, and a circulation pump 134 as a circulation unit. The printhead unit 130 is a circulation type printhead unit that continuously circulates liquid in the ink tank 132, the pressure chamber 31, the air chamber 32, and the ink chamber 27 formed inside the inkjet head 10.

[0071] In this embodiment, the inkjet head 10 is equipped with four colors: cyan, magenta, yellow, and black, and ink tanks 132 that respectively store ink of these colors. The ink tanks 132 are connected to the inkjet head 10 via a connecting flow path 133. The connecting flow path 133 includes a supply flow path connected to the supply port of the inkjet head 10 and a return flow path connected to the discharge port of the inkjet head 10.

[0072] In addition, a negative pressure control device, such as a pump (not shown), is connected to the ink tank 132. Furthermore, the negative pressure control device controls the negative pressure inside the ink tank 132 in accordance with the head value of the inkjet head 10 and the ink tank 132, thereby forming a curved surface of a predetermined shape of ink supplied to each nozzle 28 of the inkjet head 10.

[0073] The circulation pump 134 is, for example, a liquid delivery pump composed of a piezoelectric pump. The circulation pump 134 is located in the supply flow path. The circulation pump 134 is connected to the drive circuit of the control unit 116 via wiring, and is configured to be controlled by the CPU (Central Processing Unit). The circulation pump 134 circulates the liquid in the circulation flow path, including the inkjet head 10 and the ink tank 132.

[0074] The conveying device 115 conveys paper P along a conveying path A from the media supply unit 112 through the image forming unit 113 to the media discharge unit 114. The conveying device 115 includes a plurality of guide plate pairs 121 and a plurality of conveying rollers 122 arranged along the conveying path A.

[0075] Multiple guide plates 121 each have a pair of plate components that are arranged opposite each other to clamp the paper P being conveyed, and guide the paper P along the conveying path A.

[0076] The conveying roller 122 is driven to rotate under the control of the control unit 116, thereby conveying the paper P downstream along the conveying path A. In addition, sensors for detecting the conveying status of the paper are arranged at various points along the conveying path A.

[0077] The control unit 116 includes: a control circuit such as a CPU that acts as a controller; a ROM (Read Only Memory) for storing various programs; a RAM (Random Access Memory) for temporarily storing various variable data, image data, etc.; and an interface unit for inputting data from the outside and outputting data to the outside.

[0078] In the inkjet printer 100 configured as described above, when the control unit 116 detects a print instruction from a user via an operation input unit in the interface, it drives the transport device 115 to transport the paper P and outputs a printing signal to the timing head-alignment unit 130 at a predetermined time, thereby driving the inkjet head 10. As an ejection operation, the inkjet head 10 sends a drive signal to the drive IC 52 based on an image signal corresponding to the image data, applies a drive voltage to the electrode layer 34 of the pressure chamber 31 via wiring, selectively drives the element wall 33 of the actuator unit 22, and ejects ink from the nozzle 28, forming an image on the paper P held on the conveyor belt 118. Additionally, as a liquid ejection operation, the control unit 116 drives the circulation pump 134 to circulate the liquid in the circulation path through the ink tank 132 and the inkjet head 10. Through a cyclic operation, the ink in ink tank 132 is driven by circulation pump 134, and the ink in ink tank 132 is supplied from supply port 25 to the first general-purpose chamber 271 of ink chamber 27 via ink supply section of manifold 18. The ink is supplied to multiple pressure chambers 31 and multiple air chambers 32 of a pair of actuator sections 22. The ink flows through pressure chamber 31 into the second general-purpose chamber 272 of ink chamber 27. The ink is discharged from discharge port 26 through ink discharge section of manifold 18 back into ink tank 132.

[0079] According to the above embodiment, by forming a throttling section at the inlet and outlet of the pressure chamber 31, ejection stability can be improved. Furthermore, the opening of the throttling section 240 into the first general-purpose chamber 271 and the second general-purpose chamber 272, which serve as general-purpose chambers of the pressure chamber 31, is smaller than the flow path cross-sectional area of ​​the pressure chamber 31. Therefore, the bulging of the meniscus during liquid ejection in the inkjet head 10 is reduced. Consequently, the meniscus recovers faster, reducing the impact on the next inkjet ejection and improving ejection stability.

[0080] Furthermore, in the inkjet head 10, by employing a structure that narrows the upper part of the slit-shaped throttling orifice 242 of the throttling section 240 using a photosensitive resin, the inflow of adhesive 291 can be suppressed, thereby improving productivity. That is, for example, when the nozzle plate 12 is joined to the actuator section 22, if the throttling section 240 is filled with residual adhesive 291, resulting in printing defects, there is a possibility of reduced productivity. However, by making the opening width of the opening end 2421 on the nozzle plate 12 side of the throttling orifice 242 sufficiently narrow, the inflow of adhesive 291 can be suppressed, thus suppressing printing defects.

[0081] Furthermore, according to the above embodiment, a photosensitive resin film 244 is formed in the groove 14 of the actuator section 22, and patterned by exposure processing, thereby forming a throttling section 240. This reduces the number of steps and allows for the inexpensive and easy formation of the throttling section 240. Moreover, since the thickness and shape of the protrusion 241 can be freely selected by comparing exposure and development, the flow resistance of the throttling section can be easily designed. Additionally, by making the surface of the photosensitive resin film 244 concave, a conical throttling orifice 242 can be easily formed. In the above embodiment, since the side portion 221 of the actuator section 22 is an inclined surface, there are fewer restrictions on the exposure direction, making exposure and development processes easier.

[0082] Furthermore, the present invention is not limited to the above-described embodiments, and the constituent elements can be modified and embodied in the implementation stage without departing from its spirit.

[0083] In the above embodiment, the throttling portion 240 that increases flow path resistance is configured as having a pair of protrusions 241 on the wall surfaces of the element walls 33 formed on both sides of the pressure chamber 31, but the shape of the throttling portion 240 is not limited to this. For example, it may also be a protrusion formed on a part of the nozzle plate 12 side of the pressure chamber 31. For example, the throttling orifice 242 is formed as a slit shape extending in a third direction that is the depth direction of the pressure chamber, but it may also extend in other directions, or it may be other shapes including circles and ellipses.

[0084] For example, the throttle orifice 242 is not limited to being formed as a cone shape that gradually widens at the bottom. As an example, it can also be configured such that the opening width on both sides in the depth direction, that is, on the bottom side opposite to the opening end 2421, is smaller than that in the center. Alternatively, it can be a structure in which the opening end 2421 is narrowed in a portion of the area on the nozzle plate 12 side, while the other bottom side areas have a constant opening width larger than the opening end 2421.

[0085] Alternatively, the throttling sections 240 on both sides can have different structures. For example, by using the protrusion 241 to form the throttling section 240 in at least one communication port of the pressure chamber 31 that communicates with the general chambers 271 and 272 on both sides, it is possible to achieve the effects of improved ejection performance and the ability to form the throttling section 240 inexpensively and easily.

[0086] Furthermore, the cover 23 and the protrusion 241 are formed to be inside the groove 14 that forms the pressure chamber 31 and the air chamber 32, and to fill a portion of the groove 14, but this is not a limitation. For example, on the side of the actuator, a cover 23 that blocks the air chamber 32 and a protrusion 241 that blocks a portion of the communication port of the pressure chamber 31 may be formed on the outside of the groove 14 that forms the pressure chamber 31 and the air chamber 32, and the throttling portion 240 may be formed on the outside of the groove 14 and the element wall 33.

[0087] In the above embodiment, an example is shown where an actuator section 22 with multiple slots 14 is disposed on the main surface of the substrate 21, but this is not a limitation. For example, the actuator may be provided on the end face of the substrate 21. In addition, the number of nozzle rows is not limited to the above embodiment, and may be configured to have one row or three or more rows.

[0088] Furthermore, in the above embodiment, an actuator base 11 consisting of a stacked piezoelectric element made of piezoelectric components is shown as an example, but it is not limited to this. For example, the actuator base 11 may be formed solely of piezoelectric components without using a substrate. Alternatively, instead of using two piezoelectric components, only one piezoelectric component may be used. Additionally, the air chamber 32 may be connected to the first general-purpose chamber 271 and the second general-purpose chamber 272, which serve as general-purpose chambers. Furthermore, the supply side and the discharge side may be opposite, or they may be configured to be switchable.

[0089] Furthermore, in the above embodiment, as an example, one side of the pressure chamber 31 in the second direction is the supply side, and the other side in the second direction is the discharge side. The fluid in the first general chamber flows into the pressure chamber from one side and flows out from the other side in a circulating type inkjet head, but it is not limited to this. For example, it can also be a non-circulating type. In addition, for example, the general chambers on both sides of the pressure chamber 31 can be used as the supply side, and the fluid flows in from both sides. That is, the structure can also be used in which the fluid flows in from both sides of the pressure chamber 31 and flows out from the nozzle 28 disposed in the center of the pressure chamber 31. Even in this case, by providing throttling sections 240 at the connecting ports that become the inlets on both sides of the pressure chamber 31, it is possible to increase the flow path resistance and improve the ejection efficiency. In addition, the structures of the throttling sections 240 formed at both ends can also be different.

[0090] Furthermore, in the above embodiment, an example is shown in which the throttling section 240 is formed at both ends in the extending direction of the pressure chamber 31. However, this is not a limitation. The throttling section 240 may also be formed only on one side of the inlet / outlet on both sides of the pressure chamber 31 that connects to the universal chambers 271 and 272 at both ends. For example, it may be a structure in which a throttling section 240 with a flow resistance greater than that inside the pressure chamber 31 is formed at one end, and the other end has the same flow resistance as inside the pressure chamber 31, for example, the same cross-sectional area of ​​the communication opening as the cross-sectional area of ​​the cross-section of the pressure chamber 31.

[0091] In the above embodiment, a side-jet type is shown where both sides of the pressure chamber 31 are connected to the ink chamber 27, but it is not limited to this. For example, it could also be an end-jet type where only one side of the pressure chamber 31 is connected to the ink chamber 27.

[0092] Furthermore, in the above embodiment, an example is shown where protrusions 241 are formed on both sides, but this is not a limitation. For example, protrusions 241 may also be formed only on one side of the component wall 33.

[0093] In the above embodiment, an example is shown in which the direction of the exposed light is set as the diffusion direction by forming a photosensitive resin film 244 with a concave surface, but it is not limited to this. For example, the exposure depth and curing area can also be set by setting the exposure direction to be inclined relative to the depth direction of the groove 14.

[0094] In addition, for example, the liquid ejected is not limited to printing ink; for example, it could be a device that ejects a liquid containing conductive particles for forming wiring patterns on a printed wiring substrate.

[0095] Furthermore, in the above embodiments, an example of using the inkjet head in a liquid ejection device such as an inkjet printer is shown, but it is not limited to this. For example, it can also be used in 3D printers, industrial manufacturing machinery, and medical applications, enabling miniaturization, lightweighting, and cost reduction.

[0096] According to at least one embodiment described above, a liquid ejector head and a method for manufacturing the liquid ejector head can be provided, which can ensure stable ejection characteristics.

[0097] While several embodiments have been described, these embodiments are merely illustrative and not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and likewise within the scope of the invention as described in the claims and its equivalents.

Claims

1. A liquid ejector head, comprising: The actuator section has a groove constituting a plurality of pressure chambers and a plurality of sidewall portions formed between the grooves constituting the pressure chambers; A nozzle plate is disposed opposite to one side of the plurality of pressure chambers; and The throttling section comprises a pair of opposing throttling walls that block a portion of the communication port of the actuator section and form a narrowed throttling port on one side in the depth direction of the pressure chamber. The communication port is a connection between the pressure chamber and a general chamber communicating with the pressure chamber. The opposing surfaces of the pair of throttling walls are inclined such that their top sides approach each other, and the distance between the opposing surfaces gradually widens on the bottom side. The top side refers to the side that is bonded to the nozzle plate, and the bottom side refers to the side that is separated from the side that is bonded to the nozzle plate.

2. The liquid ejector head according to claim 1, wherein, The plurality of said grooves and the plurality of said sidewall portions are arranged side by side in a first direction. The throttling section is provided on the side wall portion and has a throttling wall such that the width dimension of the communication port in the first direction is narrower than the width dimension of the interior of the pressure chamber in the first direction. The throttling section is configured such that the flow resistance of the throttling section is greater than the flow resistance of the pressure chamber. An adhesive layer is provided between the top of the sidewall portion and the nozzle plate.

3. The liquid ejector head according to claim 2, wherein, The throttling wall is made of photosensitive resin. The throttling orifice is a tapered slit widened at the bottom side of the pressure chamber.

4. The liquid ejector head according to claim 1, wherein, The liquid nozzle is a side-spray type liquid nozzle. The actuator section has multiple air chambers respectively formed between the multiple pressure chambers. The pressure chamber and the air chamber are arranged side by side in a first direction and extend respectively into a second direction that intersects the first direction. The throttling section is respectively arranged at both ends of the pressure chamber in the second direction, and the two ends of the pressure chamber are respectively connected to the general chamber through the throttling port.

5. The liquid ejector head according to claim 1, wherein, The opening width of the nozzle plate side opening of the throttling orifice is configured to maintain the width of the uncured adhesive through surface tension.

6. The liquid ejector head according to any one of claims 1 to 5, wherein, The throttling wall consists of a pair of protrusions. The pair of protrusions are formed along the entire length of the groove in the pressure chamber in the depth direction.

7. The liquid ejector head according to any one of claims 1 to 5, wherein, The throttling wall consists of a pair of protrusions. The pair of protrusions are formed on a portion of the depth direction of the groove in the pressure chamber.

8. The liquid ejector head according to any one of claims 1 to 3 and 5, wherein, The throttling section is formed by exposing a photosensitive resin film formed on the inner wall of the pressure chamber.

9. The liquid ejector head according to claim 4, wherein, The throttling section is formed by exposing a photosensitive resin film formed on the inner wall of the pressure chamber and the air chamber.

10. The liquid ejector head according to claim 2, wherein, The orifice is circular or elliptical.

11. The liquid ejection head according to any one of claims 1 to 5, wherein The top surface portion of the actuator portion is adhered to the nozzle plate by an adhesive layer.

Images