Liquid nozzle

Abstract

The present invention provides a liquid ejecting head capable of ensuring stable ejection characteristics. The liquid ejecting head according to one embodiment includes an actuator, a common chamber, and a cover portion. The actuator has a plurality of grooves and side walls, and the plurality of grooves constitute a plurality of pressure chambers and a plurality of dummy chambers connected to the nozzles. The common chamber is connected to both ends of the plurality of pressure chambers. The cover portion has a throttle port, which blocks a part of the communication port connecting the pressure chamber and the common chamber at both ends of the pressure chamber, and is connected to the pressure chamber, and the fluid resistance is greater than that inside the pressure chamber. The cover portion integrally includes a first portion and a second portion, the first portion is formed to overlap with the side wall and is arranged in the groove, the second portion is formed outside the groove, and the dimension of the first portion in the extension direction of the pressure chamber is more than 50% of the dimension of the cover portion in the extension direction of the pressure chamber.

Description

Technical Field

[0001] An embodiment of the present invention relates to a liquid ejecting head. Background Art

[0002] In recent years, inkjet heads have been required to have high productivity, and high speed and increased droplet volume have become issues. For example, inkjet heads of the shared mode and shared wall type are high-power and suitable for ejecting high-viscosity inks and ejecting large droplets. In shared mode / shared wall type inkjet heads, the so-called three-cycle drive is generally adopted, that is, two pressure chambers share the same drive column, and 1 / 3 of the multiple arranged chambers are driven simultaneously as pressure chambers. In addition, an independent drive head has been developed that uses the two sides of the driven pressure chamber as virtual pressure chambers and drives one pressure chamber with two independent drive columns. For example, the following structure has been developed: a plurality of grooves are formed on the piezoelectric body, and the entrance and exit are blocked every other groove. The grooves whose entrances and exits are not blocked are used as pressure chambers, and the blocked grooves are used as air chambers for independent driving.

[0003] In such an inkjet head, after ejecting an ink droplet, ink is replenished from the common liquid chamber to the pressure chamber. During this process, nozzle overspray occurs, causing the meniscus to bulge. The lower the fluid resistance in the flow path from the common liquid chamber to the nozzle, the greater the overspray. If this overspray is not converged, ejection cannot proceed with a stable meniscus. Therefore, to achieve higher inkjet head speeds, it is necessary to quickly converge the meniscus to ensure stable ejection characteristics. Summary of the Invention

[0004] Technical problem to be solved by the invention

[0005] An object of the present invention is to provide a liquid ejecting head capable of ensuring stable ejection characteristics.

[0006] Technical solutions to technical problems

[0007] The liquid ejecting head according to one embodiment is a side-jet type and includes an actuator, a common chamber, and a cover. The actuator has a plurality of grooves and side walls. The plurality of grooves constitute a plurality of pressure chambers connected to a plurality of nozzles for ejecting liquid and a plurality of dummy chambers arranged between the plurality of pressure chambers. The side walls are formed between the plurality of grooves and change the volume of the pressure chambers according to a drive signal. The common chamber is connected to both ends of the plurality of pressure chambers. The cover has a throttle port that blocks a portion of the communication port connecting the pressure chamber and the common chamber at both ends of the pressure chamber and is connected to the pressure chamber, and has a fluid resistance greater than that inside the pressure chamber. The cover integrally includes a first portion and a second portion. The first portion is formed to overlap with the side wall and is arranged in the groove, and the second portion is formed outside the groove. The dimension of the first portion in the direction in which the pressure chamber extends is at least 50% of the dimension of the cover in the direction in which the pressure chamber extends. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view showing an inkjet head according to the embodiment.

[0009] Figure 2 It is an exploded perspective view showing a partial configuration of an inkjet head according to an embodiment.

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

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

[0012] Figure 5 It is an explanatory diagram showing the structure of the throttle portion of the inkjet head according to the first embodiment.

[0013] Figure 6 This is an explanatory diagram showing the structure of a throttle portion of an inkjet head according to Comparative Example 1.

[0014] Figure 7 This is a graph showing measured values ​​of the dimensions of the throttle portion of the inkjet head according to the first embodiment and the comparative example 1.

[0015] Figure 8 It is an explanatory diagram showing the structure of a throttle portion of an inkjet head according to the second embodiment.

[0016] Figure 9 It is an explanatory diagram showing the structure of a throttle portion of an inkjet head according to a third embodiment.

[0017] Figure 10 It is an explanatory diagram showing the structure of a throttle portion of an inkjet head according to a fourth embodiment.

[0018] Figure 11 It is an explanatory diagram showing the structure of a throttle portion of an inkjet head according to Comparative Example 2.

[0019] Figure 12 It is an explanatory diagram of the inkjet head according to Test Example 1 and Test Example 2.

[0020] Figure 13 This is a graph showing the ejection speed of the inkjet head according to Test Example 1.

[0021] Figure 14 This is a graph showing the ejection speed of the inkjet head according to Test Example 2.

[0022] Figure 15 Graphs showing meniscus recovery characteristics of the inkjet heads according to Test Examples 1 and 2.

[0023] Figure 16 It is an explanatory diagram of the end-shooting type inkjet head according to Test Examples 1 and 3.

[0024] Figure 17 Graphs showing driving waveforms of the inkjet heads according to Test Examples 1 and 3.

[0025] Figure 18 This is a graph showing nozzle flow velocity vibrations of the inkjet heads according to Test Examples 1 and 3.

[0026] Figure 19 This is a graph showing the discharge volumes of the inkjet heads according to Test Examples 1 and 3.

[0027] Figure 20 Graphs showing meniscus recovery characteristics of the inkjet heads according to Test Examples 1 and 3.

[0028] Figure 21 It is a schematic diagram showing an inkjet printer according to the embodiment. DETAILED DESCRIPTION

[0029] Below, refer to Figures 1 to 11 The structure of the inkjet head 10 which is a liquid ejecting head according to the first embodiment will be described. Figure 1 is a perspective view showing an inkjet head according to the first embodiment. Figure 2 This is an exploded perspective view of part of the inkjet head. Figure 3 、 Figure 4 This is a cross-sectional view showing an enlarged structure of a portion of the inkjet head. Figure 5 as well as Figure 6 is an explanatory diagram of the throttle portion of the inkjet head according to the first embodiment and the comparative example 1. Figure 7Graph showing measured values ​​of the throttle portion of the first embodiment and the comparative example 1. Figure 8 1 is an explanatory diagram showing the structure of a throttle portion according to the second embodiment. Figure 9 is an explanatory diagram showing the structure of a throttle portion according to the third embodiment. Figure 10 It is an explanatory diagram showing the structure of a throttle portion according to the fourth embodiment. Figure 11 This is an explanatory diagram illustrating the configuration of the throttle portion of Comparative Example 2. In the figure, X, Y, and Z represent the first, second, and third directions, respectively, which are mutually orthogonal. It should be noted that in this embodiment, the directions are described based on the arrangement of the nozzles 28 and pressure chambers 31 of the inkjet head 10 along the X-axis, the extension of the pressure chambers 31 along the Y-axis, and the ejection direction of the liquid along the Z-axis, but this is not limiting.

[0030] like Figures 1 to 4 As shown, the inkjet head 10 is a so-called side-jet type shared-mode, shared-wall inkjet head. The inkjet head 10 is a device for ejecting ink, and is, for example, mounted inside an inkjet printer. For example, the inkjet head 10 is an independently driven inkjet head with alternating pressure chambers 31 and dummy chambers 32. The dummy chambers 32 are air chambers to which ink is not supplied and do not have nozzles 28.

[0031] The inkjet head 10 includes an actuator base 11, a nozzle plate 12, and a frame 13. In the actuator base 11, an ink chamber 27 is formed inside the inkjet head 10 to supply ink as an example of liquid.

[0032] The inkjet head 10 also includes components such as a circuit board 17 for controlling the inkjet head 10 and a manifold 18 that forms a portion of a path between the inkjet head 10 and the ink tank.

[0033] like Figure 2 As shown, the actuator base 11 includes a base plate 21 , a pair of actuator members 22 , and a cover portion 23 .

[0034] The substrate 21 is an example of a base material and is formed into a rectangular plate from a ceramic such as alumina. The substrate 21 has a flat mounting surface. A pair of actuator components 22 are bonded to the mounting surface of the substrate. A plurality of supply holes 25 and discharge holes 26 are formed in the substrate 21.

[0035] like Figure 2 As shown, pattern wiring 211 is formed on the substrate 21 of the actuator base 11. The pattern wiring 211 is formed of, for example, a nickel thin film. The pattern wiring 211 has a common pattern and individual patterns and is formed into a predetermined pattern shape that connects to the electrode layer 34 formed on the actuator component 22.

[0036] Supply holes 25 are arranged in the center of the substrate 21, between the pair of actuator members 22, and along the longitudinal direction of the actuator members 22. Supply holes 25 communicate with the ink supply section of the manifold 18. Supply holes 25 are connected to the ink tank via the ink supply section. Supply holes 25 supply ink from the ink tank to the ink chamber 27.

[0037] The discharge holes 26 are arranged in two rows, sandwiching the supply holes 25 and the pair of actuator members 22. The discharge holes 26 communicate with the ink discharge section of the manifold 18. The discharge holes 26 are connected to the ink tank via the ink discharge section. The discharge holes 26 discharge the ink in the ink chamber 27 into the ink tank.

[0038] A pair of actuator components 22 are bonded to the mounting surface of the substrate 21. The pair of actuator components 22 are arranged in two rows on the substrate 21 with the supply hole 25 sandwiched therebetween. Each actuator component 22 is formed by two plate-shaped piezoelectric bodies, and the two plate-shaped piezoelectric bodies are formed, for example, of lead zirconate titanate (PZT). The two piezoelectric bodies are bonded in such a way that the polarization directions are opposite to each other in the thickness direction. The actuator components 22 are bonded to the mounting surface of the substrate 21, for example, by a thermosetting epoxy adhesive. Figure 2 As shown, the actuator member 22 is arranged parallel to the nozzles 28 arranged in two rows in the ink chamber 27. The actuator member 22 divides the ink chamber 27 into a first common chamber 271 where the supply hole 25 opens and two second common chambers 272 where the discharge holes 26 open.

[0039] A pair of actuator components 22 are arranged with their longitudinal directions along the first direction, and their cross-sections perpendicular to the first direction are formed into a trapezoidal shape. The side surfaces 221 of the actuator components 22 have inclined surfaces that are inclined relative to the second and third directions. That is, the actuator components 22 are formed into a trapezoidal shape in a cross-sectional view perpendicular to the second direction. The top of the actuator component 22 is bonded to the nozzle plate 12. The actuator component 22 includes a plurality of pressure chambers 31 and a plurality of dummy chambers 32. The actuator component 22 has a plurality of side walls 33, and grooves forming the pressure chambers 31 and dummy chambers 32 are formed between the side walls 33. In other words, the side walls 33 serve as driving elements formed between the grooves forming the pressure chambers 31 and dummy chambers 32. The plurality of pressure chambers 31 and dummy chambers 32 are formed by grooves that are open at both ends in the second direction and on one side in the third direction.

[0040] like Figures 1 to 4 As shown, the bottom portion of the groove is connected to the main surface of the substrate 21 via an inclined side portion 221. The pressure chambers 31 and the dummy chambers 32 are arranged alternately. The pressure chambers 31 and the dummy chambers 32 each extend in a direction intersecting the longitudinal direction of the actuator member 22, and a plurality of the pressure chambers 31 and the dummy chambers 32 are arranged in the longitudinal direction of the actuator member 22, i.e., in the first direction (the X-axis in the figure).

[0041] It should be noted that the shapes of the pressure chamber 31 and the dummy chamber 32 may be different. The side wall 33 is formed between the pressure chamber 31 and the dummy chamber 32 and deforms according to a driving signal to change the volume of the pressure chamber 31.

[0042] The multiple pressure chambers 31 communicate with the multiple nozzles 28 of the nozzle plate 12 attached to the top. Both ends of the pressure chambers 31 in the second direction communicate with the ink chamber 27. Specifically, one end opens into the first common chamber 271 of the ink chamber 27, and the other end opens into the second common chamber 272 of the ink chamber 27. Therefore, ink flows into the pressure chamber 31 from one end and out from the other end. A throttle portion 240 is formed at each end of the pressure chamber 31, creating a greater fluid resistance than that within the pressure chamber 31.

[0043] One side of the dummy chamber 32 in the third direction is blocked by the nozzle plate 12, which is bonded to the top portion 222. Furthermore, multiple dummy chambers 32, for example, are blocked at both ends in the second direction by the cover portion 23. Specifically, the cover portion 23 is disposed between the first common chamber 271 of the ink chamber 27 and the entrance of the dummy chamber 32, and between the exit of the dummy chamber 32 and the second common chamber 272. The dummy chambers 32 are isolated from the ink chamber 27 at both ends. Consequently, the dummy chambers 32 constitute air chambers into which ink does not flow.

[0044] Electrode layers 34 are provided in the pressure chamber 31 and the dummy chamber 32 of the actuator base 11. Electrode layers 34 are formed, for example, from a nickel thin film. Electrode layers 34 extend from the inner surface of the groove onto the substrate 21 and are connected to the pattern wiring 211. Electrode layers 34 are formed on the inner walls of the groove. For example, electrode layers 34 are formed on the side or bottom portions of the sidewalls 33.

[0045] The cover portions 23 are provided at both ends of the groove in the second direction that forms the plurality of pressure chambers 31 and the dummy chambers 32. The cover portions 23 are made of, for example, a photosensitive resin. The cover portions 23 are formed into a predetermined shape with a slit-like opening by exposing and developing the photosensitive resin film after film formation, or by exposing, developing, and machining the photosensitive resin film after film formation. Specifically, protrusions protruding toward the pressure chambers are formed on the inner surfaces of the sidewalls 33 on both sides of the pressure chambers 31.

[0046] After the cover part 23 is coated with photosensitive resin at the entrances on both sides of the pressure chamber 31, the target part is cured by exposure, and the unnecessary unexposed resin is washed away with a developer to form a prescribed shape that blocks the two ends of the groove constituting the dummy chamber 32 and a part of the two ends of the groove constituting the pressure chamber 31.

[0047] The cover 23 blocks the end of the dummy chamber 32 in the second direction and has a plurality of protrusions 241 formed on both sides of the pressure chamber 31 in the second direction.

[0048] The pair of protrusions 241 formed at the ends of each pressure chamber 31 may be formed over the entire length in the third direction, which is the depth direction of the groove of the pressure chamber 31, or may be formed over a portion of the third direction. For example, the pair of protrusions 241 may each be formed into a rectangular shape that is elongated in the third direction.

[0049] The protrusion 241 forms a throttle portion 240 having a larger fluid resistance than that in the pressure chamber by making the opening of the communication port narrower than that in the pressure chamber.

[0050] Specifically, the groove forming the pressure chamber 31 is not completely covered by the protrusions 241. A throttle opening 242 is formed between the pair of protrusions 241, connecting the pressure chamber 31 with the first and second common chambers 271 and 272. The throttle opening 242 is a slit extending in the third direction, which serves as the depth of the pressure chamber 31. Its opening width in the first direction is smaller than the width of the interior of the pressure chamber 31 in the first direction, and thus smaller than the flow path cross-sectional area of ​​the pressure chamber 31. Specifically, the protrusions 241 partially block the communication openings at both ends in the second direction, creating the throttle portion 240 with increased flow path resistance. The throttle portion 240 is formed by exposing and developing a photosensitive resin film after film formation, or by exposing, developing, and machining the photosensitive resin film after film formation. For example, after applying a photosensitive resin to the inlets on both sides of the pressure chamber 31, the target portion constituting the protrusion 241 is cured by exposure, and then a development process is performed to wash away the unnecessary unexposed resin with a developer, thereby forming the throttle portion 240 into a predetermined shape. Alternatively, a photosensitive resin may be applied to the pressure chamber 31, and after curing the photosensitive resin at the predetermined portions of the communication openings on both sides by exposure and development, the throttle portion 242 may be formed by mechanical processing such as cutting.

[0051] It should be noted that if the fluid resistance of the throttle section 240 is too high, the ink supply to the pressure chamber 31 after the ink droplets are ejected will be slow, hindering high-speed operation. Furthermore, the rise of the meniscus varies depending on factors such as ink viscosity, ejection volume, and drive frequency. Therefore, the shape of the protrusion 241 and the size and position of the orifice 242 of the throttle section 240 are set to provide a flow resistance that corresponds to the ink supply conditions and the rise characteristics of the meniscus.

[0052] The cover portion 23 has a first portion 231 and a second portion 232. The first portion 231 is formed in the gap between the side walls 33 and overlaps the wall surface of the side wall 33. The second portion 232 is located further outward of the pressure chamber 31 than the side wall 33 in the second direction. Specifically, the orifice 242, which is formed by the protrusion 241 as part of the cover portion 23, integrally includes a first portion 2421 that overlaps the side wall 33 and a second portion 2422 that extends further outward of the pressure chamber 31 than the side wall 33 in the second direction. The dimensions of the cover portion 23, the protrusion 241, and the orifice 242 in the second direction are configured such that the portion overlapping the side wall 33 is longer than the portion formed outside the side wall 33.

[0053] For example, as a first embodiment, the first portion 231 is configured to be larger than the second portion 232. That is, at least 50% of the cover portion 23's dimension in the second direction, or its total thickness, overlaps with the side wall 33. The dimension of the first portion 2421 of the protrusion 241 in the second direction is at least 50% of the total length of the protrusion 241 in the second direction. In other words, the length of the first portion 2421 of the throttle opening 242 in the second direction is at least 50% of the total length of the throttle opening 242 in the second direction. This dimension of the first portion 2421 represents the length of the flow path of the throttle opening 242 formed by the protrusion 241. In other words, the length of the first portion 2421 is longer than the second portion 2422.

[0054] Figure 5 1 is an explanatory diagram showing the structure of the throttle portion 240 according to the first embodiment. Figure 6 It is an explanatory diagram showing the structure of a throttle portion according to Comparative Example 1. Figure 7 This is a graph showing the width a [μm] of the outlet 2431 on the inner side of the orifice 242, i.e., the pressure chamber 31 side, and the width b [μm] of the inlet 2432 on the outer side, i.e., the ink chamber 27 side, relative to the design values ​​for the first embodiment and comparative example 1. Figure 7 In the figures, both Example 1 and Comparative Example 1 show the measured values ​​of width a [μm] and width b [μm] in five different pressure chambers 31, as well as the average value [μm] and standard deviation of each width, when the number of measurements n is set to 5. Example 1 and Comparative Example 1 each show the measured values ​​in five pressure chambers 31 when the cover portion 23 is coated and then a slit serving as the orifice 242 is formed by cutting. In both Example 1 and Comparative Example 1, the design values ​​are set as follows: the orifice length, i.e., the total length of the orifice 242 in the second direction, is 500 μm; the orifice width, i.e., the dimension of the slit serving as the orifice 242 in the first direction, is 28 μm; and the groove width, i.e., the dimension of the pressure chamber 31 in the first direction, is 48 μm.

[0055] In the first embodiment, the lengths of the first and second portions are both 50% of the throttle length. In the first embodiment, the average width of the throttle opening 242 inside the pressure chamber 31 is 27.98 μm, and the standard deviations of the widths of the inner and outer openings of the throttle portion 240 are approximately 0.13 and 0.16, respectively.

[0056] In Comparative Example 1, 40% of the throttle length is used as the first portion, and 60% is used as the second portion. In the first embodiment, the width of the throttle opening 242 inside the pressure chamber 31 is an average of 27.94 μm inside the pressure chamber, and the width of the opening outside the pressure chamber is an average of 25.36 μm. In addition, the standard deviations of the width of the opening inside and outside the throttle portion 240 are 0.11 and 0.33. Figure 7 As shown, in the case of comparative example 1, the width of the slit serving as the throttle port 242 formed by machining is greatly different between the first portion 2421 overlapping with the side wall 33 and the second portion 2422 formed on the outside of the side wall 33, and the deviation in the width dimension of the inlet 2432 on the outside of each pressure chamber 31 is particularly large.

[0057] Figure 8 This is an explanatory diagram showing the configuration of the throttle portion 240 according to the second embodiment. In the second embodiment, the design values ​​are set such that the throttle length, i.e., the total length of the throttle opening 242 in the second direction, is 500 μm; the throttle width, i.e., the dimension of the slit-shaped throttle opening 242 in the first direction, is 28 μm; and the groove width, i.e., the dimension of the pressure chamber 31 in the first direction, is 48 μm. For example, in the second embodiment, the cover portion 23 is configured so that at least 80% of its dimension in the second direction, i.e., its total thickness, overlaps with the side wall 33. Specifically, in the throttle opening 242 formed by the protrusion 241, the dimension of the first portion 2421 accounts for at least 80% of the total length of the throttle opening 242 in the second direction. In addition, in the second embodiment, the size of the second part in the second direction is based on the width size of the pressure chamber 31 in the first direction, so that the size of the first part 2421 is more than 80% of the total length of the throttle port 242 in the second direction, so that the thickness of the second part in the second direction is equal to or less than the width size of the pressure chamber 31 in the first direction, or equal to or less than the width size of the pressure chamber 31 in the first direction.

[0058] Figure 9This is an explanatory diagram showing the structure of the throttle portion 240 according to the third embodiment. In the third embodiment, the design values ​​are set such that the throttle length, or the total length of the throttle opening 242 in the second direction, is 500 μm; the throttle width, or the dimension of the slit forming the throttle opening 242 in the first direction, is 28 μm; and the groove width, or the dimension of the pressure chamber 31 in the first direction, is 48 μm. For example, in the third embodiment, at least 95% of the dimension of the cover portion 23 in the second direction, or the total thickness, is used as the first portion 231 overlapping the side wall 33. Specifically, the dimension of the first portion 2421 of the throttle opening 242, formed by the protrusion 241, is at least 95% of the total length of the throttle opening 242 in the second direction. In this third embodiment, the dimension of the second portion 2422 in the second direction is equal to or less than the thickness of the protrusion 241 formed overlapping the side wall 33, or the thickness of the protrusion 241 in the first portion 2421 in the first direction. In this embodiment, the wall thickness in the pressure chamber 31 is 10 μm, which is (groove width 48 μm - slit width 28 μm) / 2. In addition, the length of the first portion 2421 is 490 μm, which is 98% of the total length. In this embodiment, based on this wall thickness, the thickness of the second portion in the second direction is set to be equal to or less than the wall thickness in the pressure chamber 31 of the first portion, or equal to or less than the wall thickness. As an example, the thickness of the second portion in the second direction is set to be less than the wall thickness of the thinnest portion among the wall thickness of the bottom and side portions in the pressure chamber 31 of the first portion, or equal to or less than the wall thickness of the thinnest portion. In this embodiment, as an example, the size of the first portion 2421 is set to be more than 95% of the total length of the throttle port 242 in the second direction.

[0059] Figure 10 This is an explanatory diagram showing the structure of the throttle portion 240 according to the fourth embodiment. In the fourth embodiment, the design values ​​are set such that the throttle length, i.e., the total length of the throttle opening 242 in the second direction, is 500 μm; the throttle width, i.e., the dimension of the slit forming the throttle opening 242 in the first direction, is 28 μm; and the groove width, i.e., the dimension of the pressure chamber 31 in the first direction, is 48 μm. In the fourth embodiment, the entirety of the cover portion 23 and the protrusion 241 is formed so as to overlap between the side walls 33 or on the inner wall of the side walls 33. In other words, there is no second portion. In this embodiment, 100% of the total thickness of the cover portion 23 constitutes the first portion 231.

[0060] The nozzle plate 12 is formed of, for example, a rectangular film made of polyimide. The nozzle plate 12 faces the mounting surface of the actuator base 11. The nozzle plate 12 has a plurality of nozzles 28 formed therein, penetrating the nozzle plate 12 in its thickness direction.

[0061] A plurality of nozzles 28 are provided in the same number as the pressure chambers 31 and are respectively arranged opposite to the pressure chambers 31. A plurality of nozzles 28 are arranged along the first direction and are arranged in two rows corresponding to the pair of actuator components 22. Each nozzle 28 is configured as a cylinder whose axis extends along the third direction. For example, the diameter of the nozzle 28 can be constant or can be a shape that tapers toward the center or the front end. The nozzles 28 are arranged opposite to the midway portion of the extension direction of the pressure chamber 31 formed on the pair of actuator components 22 and are respectively connected to the pressure chambers 31. One nozzle 28 is arranged at the center portion of each pressure chamber 31 in the longitudinal direction.

[0062] The frame 13 is formed into a rectangular frame shape from, for example, a nickel alloy. The frame 13 is interposed between the mounting surface of the actuator base 11 and the nozzle plate 12. The frame 13 is bonded to the mounting surface of the actuator base 11 and the nozzle plate 12, respectively. In other words, the nozzle plate 12 is mounted on the actuator base 11 via the frame 13.

[0063] The manifold 18 is joined to the actuator base 11 on the side opposite to the nozzle plate 12. Inside the manifold 18, an ink supply portion as a flow path communicating with the supply holes 25 and an ink discharge portion as a flow path communicating with the discharge holes 26 are formed.

[0064] The circuit board 17 is a film carrier package (FCP). It has a flexible resin film 51 with multiple wirings formed thereon, and an IC 52 connected to the wirings on the film 51. The IC 52 is electrically connected to the electrode layer 34 via the wirings on the film 51 and the pattern wiring 211.

[0065] Within the inkjet head 10 constructed as described above, an ink chamber 27 is formed, surrounded by the actuator base 11, the nozzle plate 12, and the frame 13. Specifically, the ink chamber 27 is formed between the actuator base 11 and the nozzle plate 12. For example, the ink chamber 27 is partitioned into three sections in the second direction by the two actuator members 22. The three sections include two second common chambers 272, which serve as common chambers for the discharge holes 26, and a first common chamber 271, which serves as a common chamber for the supply holes 25. The first common chamber 271 and the second common chamber 272 communicate with the plurality of pressure chambers 31.

[0066] In the inkjet head 10 constructed as described above, ink circulates between the ink tank and the ink chamber 27 through the supply holes, pressure chambers, and discharge holes. For example, based on a signal input from the inkjet printer's control unit, the driver IC 52 applies a drive voltage to the electrode layer 34 of the pressure chamber 31 via the wiring of the membrane 51. This generates a potential difference between the electrode layer 34 of the pressure chamber 31 and the electrode layer 34 of the dummy chamber 32, selectively deforming the sidewall 33 in a shared mode. By deforming the sidewall 33 formed between the pressure chamber 31 and the dummy chamber 32 in response to the drive signal, the volume of the pressure chamber 31 changes.

[0067] The shared mode deformation of the side wall 33 increases the volume of the pressure chamber 31 in which the electrode layer 34 is provided, thereby reducing the pressure.

[0068] While the volume of pressure chamber 31 is increasing, IC 52 applies a drive voltage of opposite potential to electrode layer 34 of pressure chamber 31. This causes sidewall 33 to deform in a shared mode, reducing the volume of pressure chamber 31 where electrode layer 34 is located, and increasing the pressure. This pressurizes the ink in pressure chamber 31 and causes it to be ejected from nozzle 28.

[0069] The method for manufacturing the inkjet head 10 will be described. First, a piezoelectric component with multiple grooves formed therein is attached to a plate-like substrate 21 using an adhesive or the like. Mechanical processing using a dicing saw or a slicer is then performed to form the actuator component 22 into a predetermined shape. It should be noted that, for example, a block-shaped base component can be preformed with various thicknesses and then divided to produce multiple actuator bases 11 of predetermined shapes.

[0070] Next, electrode layers 34 and pattern wiring 211 are formed on the inner surfaces of the grooves forming the pressure chambers 31 and dummy chambers 32, or on the surface of the substrate 21. As described above, the electrode layers 34 and pattern wiring 211 are formed on predetermined locations on the surface of the actuator base 11. Next, the cover portion 23 is formed from a photosensitive resin. For example, the formation of the cover portion 23 includes a filling process in which the inlets and outlets, i.e., the communication ports, on both sides of the grooves forming the dummy chambers 32 and pressure chambers 31 are filled with a photosensitive resin material, thereby sealing the communication ports at both ends with the photosensitive resin; and a forming process in which the photosensitive resin is formed into a predetermined shape. For example, after the communication ports on both sides of the grooves forming the dummy chambers 32 and pressure chambers 31 are filled with the photosensitive resin material, an exposure mask having an exposure pattern in which the portions that will become the openings of the orifices 242 remain uncured is superimposed. Exposure cures the portions other than the uncured portions that will become the orifices 242. A further development process in which the uncured portions are washed out with a developer is performed, thereby opening the orifices 242 in the predetermined shape. As a result, the photosensitive resin material is molded into a predetermined shape to form the throttle portion 240. That is, the cover portion 23 is formed, which has a pair of protrusions 241 with a throttle opening 242 formed therebetween.

[0071] Alternatively, as another example, if sufficient resolution cannot be achieved by forming a throttle pattern using exposed photosensitive resin, depending on the conditions, the throttle opening 242 may be formed by machining to form the protrusion 241. In the filling process Act 1, a photosensitive resin material is applied to and filled at both ends of the dummy chamber 32 and the pressure chamber 31. The filled photosensitive resin material is cured by exposure and development, and the communication openings of the dummy chamber 32 and the pressure chamber 31 are blocked with the walls of the photosensitive resin. Then, as the forming process, the throttle opening 242 is formed by machining using a cutter having a desired width. This forms the cover portion 23 having the protrusion 241 of a predetermined shape.

[0072] Furthermore, the actuator base 11 is assembled to the manifold 18 , and the frame 13 is adhered to one surface of the substrate 21 of the actuator base 11 via a thermoplastic resin adhesive sheet.

[0073] Then, the assembled frame 13, the top 222 of the side wall 33 of the actuator member 22, and the surface of the protrusion 241 facing the nozzle plate 12 are polished. Then, the nozzle plate 12 is bonded and mounted on the polished top 222 of the side wall 33, the frame 13, and the surface of the protrusion 241 facing each other. At this time, the nozzle 28 is positioned opposite the pressure chamber 31. In addition, as Figure 1 As shown, the driver IC chip 52 and the circuit board 17 are connected to the pattern wiring 211 formed on the main surface of the substrate 21 via the flexible printed substrate, thereby completing the inkjet head 10.

[0074] Below, refer to Figure 21 An example of an inkjet printer 100 including the inkjet head 10 will be described. The inkjet printer 100 includes a housing 111 , a medium supply unit 112 , an image forming unit 113 , a medium discharge unit 114 , a transport device 115 , and a control unit 116 .

[0075] The inkjet printer 100 is a liquid ejecting device that ejects liquids such as ink while transporting a recording medium (e.g., paper P) as an ejection object along a specified conveying path A from a medium supply unit 112 through an image forming unit 113 to a medium discharge unit 114, thereby performing image formation processing on the paper P.

[0076] The housing 111 forms the outer shell of the inkjet printer 100. A discharge port for discharging the paper P to the outside is provided at a predetermined position of the housing 111.

[0077] The medium supply unit 112 includes a plurality of paper feed cassettes and is configured to be able to stack and hold a plurality of sheets of paper P of various sizes.

[0078] The medium discharge unit 114 includes a paper discharge tray configured to hold the paper P discharged from the discharge port.

[0079] The image forming section 113 includes a support portion 117 that supports the paper P, and a plurality of head units 130 that are arranged to face each other above the support portion 117 .

[0080] The support portion 117 includes a conveyor belt 118 provided endlessly in a predetermined area where image formation is performed, a support plate 119 supporting the conveyor belt 118 from the rear side, and a plurality of belt rollers 120 provided on the rear side of the conveyor belt 118 .

[0081] During image formation, the support portion 117 supports the paper P on the holding surface, which is the upper surface of the conveyor belt 118 , and conveys the conveyor belt 118 at a predetermined timing by the rotation of the belt roller 120 , thereby conveying the paper P downstream.

[0082] The head unit 130 includes: a plurality of (four-color) inkjet heads 10; an ink tank 132, serving as a liquid tank, mounted on each inkjet head 10; a connecting flow path 133 connecting the inkjet heads 10 and the ink tank 132; and a circulation pump 134, serving as a circulation unit. The head unit 130 is a circulation-type head unit that constantly circulates liquid through the ink tank 132, the pressure chamber 31 formed within the inkjet head 10, the dummy chamber 32, and the ink chamber 27.

[0083] In this embodiment, an inkjet head 10 for four colors, namely cyan, magenta, yellow, and black, is provided, and ink tanks 132 are provided to contain inks of these colors. The ink tanks 132 are connected to the inkjet head 10 via connecting flow paths 133. The connecting flow paths 133 include a supply flow path connected to the supply port of the inkjet head 10 and a recovery flow path connected to the discharge port of the inkjet head 10.

[0084] A negative pressure control device, such as a pump (not shown), is connected to the ink tank 132. The negative pressure control device controls the negative pressure within the ink tank 132 in accordance with the hydraulic head value between the inkjet head 10 and the ink tank 132, thereby forming a meniscus of a predetermined shape in the ink supplied to each nozzle 28 of the inkjet head 10.

[0085] The circulation pump 134 is a liquid delivery pump, for example, a piezoelectric pump. It is provided in the supply flow path. The circulation pump 134 is connected to the drive circuit of the control unit 116 via wiring and is controlled by the CPU (Central Processing Unit). The circulation pump 134 circulates the liquid in the circulation flow path that includes the inkjet head 10 and the ink tank 132.

[0086] The transport device 115 transports the paper P along a transport path A from the medium supply unit 112 through the image forming unit 113 to the medium discharge unit 114 . The transport device 115 includes a plurality of guide plate pairs 121 arranged along the transport path A and a plurality of transport rollers 122 .

[0087] Each of the plurality of guide plate pairs 121 includes a pair of plate members disposed opposite to each other with the paper P being transported interposed therebetween, and guides the paper P along the transport path A.

[0088] The transport roller 122 is driven and rotated under the control of the control unit 116 to transport the paper P downstream along the transport path A. Sensors for detecting the transport status of the paper are arranged at various locations along the transport path A.

[0089] The control unit 116 includes: a control circuit, a CPU serving as a controller, etc.; a ROM (Read Only Memory) for storing various programs, etc.; a RAM (Random Access Memory) for temporarily storing various variable data or image data, etc.; and an interface unit for inputting data from the outside and outputting data to the outside.

[0090] In the inkjet printer 100 configured as described above, the control unit 116, for example, drives the transport device 115 to transport the paper P when the interface detects a print instruction issued by the user via an operation input unit. It also outputs a print signal to the head unit 130 at a predetermined timing, thereby driving the inkjet head 10. In the ejection operation, the inkjet head 10 transmits a drive signal to the IC based on an image signal corresponding to image data. This signal applies a drive voltage to the electrode layer 34 of the pressure chamber 31 via wiring, selectively driving the sidewalls 33 of the actuator member 22 to eject ink from the nozzles 28, forming an image on the paper P held on the transport belt 118. Furthermore, in the liquid ejection operation, the control unit 116 drives the circulation pump 134 to circulate liquid through the circulation path passing through the ink tank 132 and the inkjet head 10. This circulation operation causes the ink in the ink tank 132 to flow as follows: The ink in the ink tank 132 is supplied from the ink supply portion of the manifold 18 through the supply port 25 to the first common chamber 271 of the ink chamber 27 by the drive of the circulation pump 134. The ink is supplied to the plurality of pressure chambers 31 and the plurality of dummy chambers 32 of the pair of actuator members 22. The ink flows through the pressure chambers 31 and the dummy chambers 32 into the second common chamber 272 of the ink chamber 27. The ink is discharged from the discharge holes 26 through the ink discharge portion of the manifold 18 to the ink tank 132.

[0091] According to the above-mentioned embodiment, a liquid ejection head and a method for manufacturing the liquid ejection head can be provided that can ensure stable ejection characteristics. That is, the inkjet head 10 involved in the above-mentioned embodiment has a cover portion 23 in the pressure chamber 31, so that the flow resistance of the inlet and outlet of the pressure chamber 31 is greater than that of the interior of the pressure chamber 31, the first common chamber 271, and the second common chamber 272. As a specific example, the area of ​​the opening portion of the first common chamber 271 and the second common chamber 272, which are the common chambers of the pressure chamber 31, is smaller than the flow path cross-sectional area of ​​the pressure chamber 31. Therefore, the bulge of the meniscus when liquid is ejected in the inkjet head 10 becomes smaller. Therefore, the recovery of the meniscus becomes faster, which can reduce the impact on the next ink droplet and improve the ejection stability.

[0092] Figure 12 These are Test Example 1 of the inkjet head 110 including the throttle portion (throttle portion 240 ) and Test Example 2 of the inkjet head 1010 not including the throttle portion. Figure 13 The frequency characteristics of the inkjet head 110 having the throttle portion according to Experimental Example 1 are shown. Figure 14 The frequency characteristics of the inkjet head 1010 without a throttle portion as comparative example 2 are shown. Figure 13 as well as Figure 14 , the relationship between the ejection speed and frequency of each nozzle in the case of 1 drop and 3 drops is shown respectively.

[0093] The inkjet head 110 according to Test Example 1 is a side-shooter type, in which both sides of the pressure chamber 31 in the second direction of extension communicate with the common chamber, and the nozzle 28 opens midway in the extension direction of the pressure chamber 31 .

[0094] like Figure 14 As shown, in the inkjet head 1010 involved in Test Example 2, the ejection speed is flat in the low-frequency region, but tends to decrease as the frequency increases, and there is a difference in the ejection speed between the low-frequency region and the high-frequency region. In the case of one drop, the ejection speed of the inkjet head 1010 involved in Test Example 2 is flat up to 25 kHz, but tends to decrease as the frequency increases above 25 kHz. In addition, in the case of three drops, the ejection speed of the inkjet head 1010 involved in Test Example 2 is flat up to 15 kHz, but tends to decrease as the frequency increases above 15 kHz. Therefore, the landing position will be offset depending on the printed pattern. In this way, if the difference in ejection speed is large, it takes time for the bulge of the meniscus to converge, resulting in a decrease in printing quality, and therefore high-speed driving cannot be performed.

[0095] On the other hand, Figure 13As shown, in the inkjet head 110 having a throttle portion, the ejection speed of both one drop and three drops tends to be flat. This is because the fluid resistance between the common liquid and the nozzle increases, and the meniscus rises smaller.

[0096] in addition, Figure 15 The simulation results of the meniscus recovery for the test example 1 in which a throttle portion is provided in the pressure chamber and the test example 2 in which a throttle portion is not provided are shown. Figure 15 When the meniscus state of the nozzle is low-frequency, sufficient time is required from ejecting an ink droplet to ejecting the next ink droplet. Regardless of whether there is a throttling portion, the ink can be ejected in a stable state after waiting for the meniscus to recover. On the other hand, in the case of high frequency, since the time from the ejection point (ink droplet) to the ejection of the next ink droplet is short, the ejection of the next ink droplet begins before the meniscus recovers. Therefore, in the case of the inkjet head 1010 without a throttling portion, after ejection, the bulge of the meniscus becomes larger, the meniscus cannot recover before the next ink droplet is ejected, and the ejection speed decreases. In contrast, in the case of a throttling portion, since the bulge of the meniscus becomes smaller, the recovery of the meniscus becomes faster, which can reduce the impact on the next ink droplet. Therefore, from these simulation results, it can be seen that by providing a throttling portion between the pressure chamber 31 and the common chamber, the ejection stability of the inkjet head 110 can be improved.

[0097] Figure 16 The diagrams illustrate a side-shooter inkjet head 110 as Test Example 1 and a shared-mode shared-wall end-shooter inkjet head 2010 as Test Example 3 having an ink inlet and outlet formed at one end and nozzles formed at the other end.

[0098] Figures 17 to 20 This is a diagram comparing simulation characteristics when a throttle portion is provided in the end-shooting type inkjet head 2010 of Test Example 3 and the side-shooting type inkjet head 110 of Test Example 1, respectively. Figure 17 Represents the driving waveform, Figure 18 Indicates nozzle flow velocity vibration, Figure 19 Indicates the ejection volume, Figure 20 Indicates the recovery characteristics of the meniscus.

[0099] Furthermore, the inkjet head 2010 used in Experimental Example 3 is an end-shooter type. One end of the pressure chamber 31 extending in the second direction, i.e., in communication with the common chamber, is closed at the other end, and the nozzle is open at the end of the flow path. In other words, the inkjet head 2010 forms a flow path for liquid to flow from one end in the second direction toward the nozzle 28.

[0100] For the end-shooter inkjet head 2010 (Test Example 3), which supplies ink from one side, and the side-shooter inkjet head 110 (Test Example 1), which supplies ink from both sides, the side-shooter inkjet head with both sides achieved the lowest driving voltage when achieving the desired balance between ejection volume, nozzle flow velocity oscillation, and meniscus recovery characteristics. Therefore, it can be said that the side-shooter inkjet head with both sides is superior to the single-shooter inkjet head in terms of driving efficiency. Specifically, the so-called side-shooter inkjet head 110, which has a nozzle in the center of the pressure chamber and ink inlets and outlets at both ends, exhibits superior ejection efficiency compared to the end-shooter inkjet head 2010.

[0101] It should be noted that, in general, in shared-mode, shared-wall inkjet heads, for example, the pressure chamber is formed by fine grooves formed in the piezoelectric element using a diamond cutter, making it difficult to reduce the cross-section of a portion of the pressure chamber. However, according to the above embodiment, by setting the first portion 2421 of the orifice 242, which is sandwiched by the side walls 33, to at least 50%, it is easy to design the shape of the orifice 240 with high precision. Furthermore, by reducing the second portion 2422 protruding from the side walls 33 toward the outside of the pressure chamber 31, dimensional variation can be suppressed, stabilizing the flow resistance of the orifice 242. Furthermore, in the above embodiment, the side surface 221 of the actuator member 22 is formed as an inclined surface, which reduces restrictions on the exposure direction and facilitates exposure and development processes. Furthermore, by combining machining, even finer pattern formation with high precision can be achieved.

[0102] Furthermore, in the second embodiment, by setting the first portion 2421 of the orifice 242, which is sandwiched between the side walls 33, to 80% or more and setting the size of the second portion 2422 protruding outside the pressure chamber 31 to be equal to or smaller than the width of the pressure chamber 31, the generation of bubbles larger than those inside the pressure chamber 31 can be suppressed. Consequently, the size of the orifice 242 can be set with high precision, stabilizing the flow resistance of the orifice 242.

[0103] In the third embodiment, the first portion 2421 of the orifice 242 sandwiched by the side wall 33 is set to 90% or more, and the size of the second portion 2422 protruding outside the pressure chamber 31 is set to be equal to or smaller than the wall thickness inside the pressure chamber 31, thereby suppressing the influence of swelling and the like. In other words, although swelling may occur depending on the type of ink, as long as the thickness is less than the wall thickness inside the pressure chamber, the effect of swelling and the like can be suppressed. Figure 11 As shown in Comparative Example 2, the swelling can be suppressed to a lesser extent than when the thickness of the second portion is large. Therefore, the size of the orifice 242 can be set with high precision, and the flow path resistance of the orifice 242 can be stabilized.

[0104] Furthermore, in the inkjet head 10 according to the above embodiment, since a throttle portion is locally formed in the communication port serving as the entrance and exit of the pressure chamber 31, it is easier to maintain the volume of the pressure chamber 31 than if the width of the pressure chamber 31 were reduced as a whole. Therefore, compared to a configuration in which the width of the pressure chamber is reduced as a whole, there are fewer restrictions on the size of the nozzles or droplets, making it easier to maintain ejection performance.

[0105] It should be noted that the present invention is not limited to the above-described embodiment itself, and in the implementation stage, the constituent elements may be modified and embodied within the scope of the present invention.

[0106] In the above embodiment, as an example, a first common chamber 271 is arranged on one side of the pressure chamber 31, and a second common chamber 272 is arranged on the other side, with fluid flowing into the pressure chamber from one side and out of the other side. However, this is not limiting. For example, a configuration in which the common chambers on both sides of the pressure chamber 31 serve as the supply side, with fluid flowing in from both sides, is also possible. In other words, a configuration in which fluid flows in from both sides of the pressure chamber 31 and flows out of the nozzle 28 located in the center of the pressure chamber 31 is also possible. In this case, by providing throttling portions at the inlets on both sides of the pressure chamber 31, it is possible to increase fluid resistance and improve discharge efficiency.

[0107] Furthermore, in the above embodiment, the throttle portion 240 for increasing the flow resistance comprises a pair of protrusions 241 formed on the wall surfaces of the side walls 33 on either side of the pressure chamber 31. However, the shape of the throttle portion 240 is not limited thereto. For example, the throttle opening 242 is formed as a slit extending in a third direction, which serves as the depth direction of the pressure chamber. However, it may also extend in other directions or have other shapes, including circular or elliptical shapes. Furthermore, the shape, position, and size of the throttle portions 240 provided on either side can be determined based on the flow resistance. The throttle portions 240 may be configured with the same conditions on both sides, or with different conditions on one throttle portion 240 from the other.

[0108] In the above embodiment, an actuator member 22 having multiple grooves is disposed on the main surface of the substrate 21, but the present invention is not limited thereto. For example, an actuator may be disposed on the end surface of the substrate 21. Furthermore, the number of nozzle arrays is not limited to the above embodiment; a configuration with one array or three or more arrays is also possible.

[0109] In addition, in the above embodiment, an example is shown in which the driver base 11 includes a laminated piezoelectric body composed of a piezoelectric component on the substrate 21, but the present invention is not limited to this. For example, the actuator component 22 can be formed only from a piezoelectric component without using a substrate. In addition, instead of using two piezoelectric components, a single piezoelectric component can be used. In addition, the dummy chamber 32 can also be connected to the first common chamber 271 or the second common chamber 272 as a common chamber. In addition, the supply side and the discharge side can be opposite, or can be configured to be switchable.

[0110] Furthermore, in the above embodiment, a circulating inkjet head is illustrated as an example, in which one side of the pressure chamber 31 serves as the supply side and the other side as the discharge side, with fluid flowing into the pressure chamber from one side and out of the other. However, this is not the only option. A non-circulating type inkjet head is also possible. Alternatively, a common chamber on either side of the pressure chamber 31 serves as the supply side, with fluid flowing in from both sides. In other words, a configuration is also possible in which fluid flows in from both sides of the pressure chamber 31 and out of the nozzle 28 located in the center of the pressure chamber 31. In this case, by providing a throttle portion 240 at the communicating openings serving as the inlets on either side of the pressure chamber 31, fluid resistance can be increased, thereby improving ejection efficiency. For example, a non-circulating type inkjet head can be configured by omitting or closing the discharge-side flow path. For example, a supply hole 25 can be provided in place of the discharge hole 26, or the discharge-side flow path can be opened only for ink replenishment or maintenance, and closed during printing, resulting in a non-circulating type inkjet head.

[0111] For example, the liquid to be discharged is not limited to ink for printing, and may be a device that discharges a liquid containing conductive particles for forming a wiring pattern of a printed wiring board.

[0112] In addition, in the above embodiment, an example of an inkjet head being used in a liquid ejecting device such as an inkjet printer is shown, but the invention is not limited thereto. For example, the inkjet head can also be used in 3D printers, industrial manufacturing machinery, and medical applications, and can achieve miniaturization, lightness, and low cost.

[0113] According to at least one embodiment described above, a liquid ejecting head capable of ensuring stable ejection characteristics and a method for manufacturing the liquid ejecting head can be provided.

[0114] Although several embodiments have been described, these embodiments are provided for illustrative purposes only and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the spirit of the invention. These embodiments and their variations are intended to be included within the scope and spirit of the invention and are also intended to be included within the scope of the invention set forth in the claims and their equivalents.

[0115] Description of Reference Numerals

[0116] 10: Inkjet head; 11: Actuator base; 12: Nozzle plate; 13: Frame; 17: Circuit board; 18: Manifold; 21: Substrate; 22: Actuator member; 23: Cover; 231: First portion; 232: Second portion; 25: Supply hole; 26: Discharge hole; 27: Ink chamber; 31: Pressure chamber; 32: Dummy chamber; 33: Side wall; 34: Electrode layer; 51: Membrane; 52: Driver IC chip; 100: Inkjet printer; 111: Frame; 112: Media supply unit; 113: Image forming unit; 114: Media discharge unit; 1 15: Conveying device; 116: Control unit; 117: Support unit; 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: Circulation pump; 211: Pattern wiring; 221: Side portion; 222: Top portion; 240: Throttle portion; 241: Protrusion; 242: Throttle port; 2421: First portion; 2422: Second portion; 271: First common chamber; 27: Ink chamber; 272: Second common chamber.

Claims

1. A side-spraying liquid ejector, comprising: The actuator comprises a plurality of grooves and sidewalls, wherein the plurality of grooves constitute a plurality of pressure chambers connected to a plurality of nozzles for ejecting liquid; and a plurality of dummy chambers disposed between the plurality of pressure chambers, wherein the sidewalls are formed between the plurality of grooves and the volumes of the pressure chambers are changed according to a drive signal. a common chamber connected to both ends of the plurality of pressure chambers; as well as The cover has a throttle port that blocks a portion of the communication port between the pressure chamber and the common chamber at both ends of the pressure chamber, forms a pair of protrusions protruding toward the side wall, and communicates with the pressure chamber, and has a fluid resistance greater than that inside the pressure chamber. The cover portion integrally includes a first portion and a second portion, the first portion being formed to overlap with the side wall and disposed within the groove, and the second portion being formed outside the groove. A dimension of the first portion in the extending direction of the pressure chamber is equal to or greater than 50% of a dimension of the cover portion in the extending direction of the pressure chamber.

2. The liquid ejecting head according to claim 1, wherein The cover is made of photosensitive resin. A dimension of the first portion in an extending direction of the pressure chamber is equal to or greater than 80% of a dimension of the cover portion in the extending direction.

3. The liquid ejecting head according to claim 1, wherein A dimension of the first portion in an extending direction of the pressure chamber is equal to or greater than 95% of a dimension of the cover portion in the extending direction.

4. The liquid ejecting head according to claim 1, wherein The liquid ejecting head is composed of: The plurality of nozzles and the plurality of pressure chambers are arranged in a row in a first direction, The pressure chambers extend respectively along a second direction intersecting the first direction, The nozzle is arranged at a position corresponding to a midway portion of the pressure chamber in the second direction. The ejection direction of the nozzle intersects the first direction and the second direction, and A size of the throttle port in the first direction is smaller than a size of the pressure chamber in the first direction.

5. The liquid ejecting head according to claim 2, wherein The liquid ejecting head is composed of: The plurality of nozzles and the plurality of pressure chambers are arranged in a row in a first direction, The pressure chambers extend respectively along a second direction intersecting the first direction, The nozzle is arranged at a position corresponding to a midway portion of the pressure chamber in the second direction. The ejection direction of the nozzle intersects the first direction and the second direction, and A size of the throttle port in the first direction is smaller than a size of the pressure chamber in the first direction. The liquid ejecting head according to claim 3 , wherein: The liquid ejecting head is composed of: The plurality of nozzles and the plurality of pressure chambers are arranged in a row in a first direction, The pressure chambers extend respectively along a second direction intersecting the first direction, The nozzle is arranged at a position corresponding to a midway portion of the pressure chamber in the second direction. The ejection direction of the nozzle intersects the first direction and the second direction, and A size of the throttle port in the first direction is smaller than a size of the pressure chamber in the first direction.

7. The liquid ejecting head according to any one of claims 1 to 6, wherein The dimension of the second portion in the extension direction of the pressure chamber is equal to or smaller than the width of the pressure chamber intersecting the extension direction.

8. The liquid ejecting head according to any one of claims 1 to 6, wherein The nozzles are provided in the same number as the pressure chambers and are arranged to face the pressure chambers.

9. The liquid ejecting head according to any one of claims 1 to 6, wherein An electrode layer and pattern wiring are formed on the inner surface of the groove.

10. The liquid ejecting head according to any one of claims 4 to 6, wherein The dimension of the second portion in the second direction is equal to or smaller than the thickness dimension of the first portion in the first direction formed in an overlapping manner on the side wall.

Images