Liquid ejection head, liquid ejection device, and method of manufacturing liquid ejection head

Abstract

A liquid ejection head, a liquid ejection device, and a method for manufacturing a liquid ejection head are provided that are capable of suppressing clogging of nozzles with foreign matter and achieving desired ejection characteristics. [Solution] A liquid ejection head having a nozzle (21) that ejects liquid and an individual flow path including a pressure chamber that applies pressure to eject liquid from the nozzle, wherein the nozzle (21) includes a first nozzle portion (22), a second nozzle portion (23), and a third nozzle portion (24) having a smaller diameter than the second nozzle portion, wherein the side wall of the first nozzle portion (22) has a plurality of first grooves (22a) aligned in the ejection direction, and the side wall of the second nozzle portion (23) has a plurality of second grooves (23a) aligned in the ejection direction, and the width W1 of each of the plurality of first grooves (22a) along the ejection direction is greater than the width W2 of each of the plurality of second grooves (23a) along the ejection direction.

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head that ejects liquid from a nozzle, a liquid ejection apparatus equipped with the liquid ejection head, and a method for manufacturing the liquid ejection head. [Background technology]

[0002] A liquid ejection head includes a nozzle plate provided with nozzles for ejecting droplets. Some nozzles include a first nozzle portion provided on the ejection surface side and a second nozzle portion that communicates with the first nozzle portion and has a larger diameter than the first nozzle portion. Such nozzles are formed by the Bosch process, which results in multiple grooves being formed in the sidewall of the nozzle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-149120 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the length of the first nozzle section of such a nozzle must be precisely controlled because it significantly contributes to the ejection characteristics, such as the flight speed and weight of ink droplets ejected from the nozzle. Since the length of the first nozzle section is determined by the length of the second nozzle section, the length of the second nozzle section is precisely controlled by reducing the etching rate and shortening the etching time when forming the second nozzle section, thereby finely cutting and creating multiple small grooves in the sidewall of the second nozzle section. However, when liquid is supplied from the upstream flow channel, foreign matter such as air bubbles, thickened substances, and dust may enter the second nozzle section. Such foreign matter may become mixed into the groove in the sidewall of the second nozzle section. In particular, if the groove of the second nozzle section is small, the liquid flow cannot easily enter, and foreign matter that has entered the groove may become trapped and clog the groove. If foreign matter clogs the groove, the nozzle shape may differ from the desired shape, resulting in the problem of not achieving the desired ejection characteristics. [Means for solving the problem]

[0005] An aspect of the present invention that solves the above problem is a liquid ejection head having a nozzle that ejects liquid and an individual flow path including a pressure chamber that applies pressure to eject liquid from the nozzle, wherein the nozzle includes a first nozzle portion, a second nozzle portion that is farther from the individual flow path in the ejection direction than the first nozzle portion, and a third nozzle portion that is farther from the individual flow path in the ejection direction than the second nozzle portion and has a smaller diameter than the second nozzle portion, wherein a side wall of the first nozzle portion has a plurality of first grooves aligned in the ejection direction, and a side wall of the second nozzle portion has a plurality of second grooves aligned in the ejection direction, and the width of each of the plurality of first grooves along the ejection direction is greater than the width of each of the plurality of second grooves along the ejection direction.

[0006] Another aspect of the present invention is a liquid ejection apparatus comprising the liquid ejection head according to any one of the above aspects.

[0007] Another aspect of the present invention is a method for manufacturing a liquid ejection head, the method comprising: forming a nozzle plate provided with nozzles that eject liquid; and individual flow paths including pressure chambers that apply pressure to eject liquid from the nozzles, the nozzles including a first nozzle portion, a second nozzle portion that is farther from the individual flow path in the ejection direction than the first nozzle portion, and a third nozzle portion that is farther from the individual flow path in the ejection direction than the second nozzle portion and has a smaller diameter than the second nozzle portion; a side wall of the first nozzle portion has a plurality of first grooves aligned in the ejection direction; a side wall of the second nozzle portion has a plurality of second grooves aligned in the ejection direction; and a width of each of the plurality of first grooves along the ejection direction is larger than a width of each of the plurality of second grooves along the ejection direction, the method comprising: forming a liquid ejection head by ejecting a liquid from one side of the nozzle plate using a Bosch pump; a second step of performing a Bosch process from the other surface side of the nozzle plate after the first step to form the first nozzle portion, the side wall of which has the plurality of first grooves aligned in the discharge direction; and a third step of performing a Bosch process from the other surface side of the nozzle plate to a part of the recess, the second nozzle portion, the side wall of which has the plurality of second grooves aligned in the discharge direction, and the third nozzle portion with the remaining part of the recess, wherein the second step and the third step use different etching conditions to make the width of each of the plurality of first grooves in the discharge direction larger than the width of each of the plurality of second grooves in the discharge direction. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a schematic configuration of a liquid ejection device according to a first embodiment. [Figure 2] FIG. 1 is an exploded perspective view of a liquid ejection head according to a first embodiment. [Figure 3] 1 is a plan view of a main part of a liquid ejection head according to a first embodiment. [Figure 4] 1 is a cross-sectional view of a main part of a liquid ejection head according to a first embodiment. [Figure 5] 2 is an enlarged cross-sectional view of a main part of the nozzle plate according to the first embodiment. FIG. [Figure 6] 4 is a flowchart of a method for manufacturing a liquid ejection head according to the first embodiment. [Figure 7] 3A to 3C are cross-sectional views of a main part illustrating a method for manufacturing the liquid ejection head according to the first embodiment. [Figure 8] 3A to 3C are cross-sectional views of a main part illustrating a method for manufacturing the liquid ejection head according to the first embodiment. [Figure 9] 3A to 3C are cross-sectional views of a main part illustrating a method for manufacturing the liquid ejection head according to the first embodiment. [Figure 10] 3A to 3C are cross-sectional views of a main part illustrating a method for manufacturing the liquid ejection head according to the first embodiment. [Figure 11] 3A to 3C are cross-sectional views of a main part illustrating a method for manufacturing the liquid ejection head according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below based on embodiments. However, the following description illustrates one aspect of the present invention and can be modified as desired within the scope of the present invention. In each drawing, the same reference numerals indicate the same components, and their description will be omitted as appropriate. In each drawing, X, Y, and Z represent three spatial axes that are orthogonal to each other. In this specification, the directions along these axes are referred to as the X direction, Y direction, and Z direction. In each drawing, the direction indicated by the arrow is the positive (+) direction, and the direction opposite the arrow is the negative (-) direction. The Z direction indicates the vertical direction, the +Z direction indicates a vertically downward direction, and the -Z direction indicates a vertically upward direction. Furthermore, the directions of the three spatial axes, which are not limited to positive and negative directions, will be described as the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0010] (Embodiment 1) FIG. 1 is a diagram showing a schematic configuration of a liquid ejection device 1 according to a first embodiment of the present invention.

[0011] As shown in FIG. 1, the liquid ejection device 1 is a so-called serial printer that includes a liquid ejection head H and prints by conveying a medium S in the X-axis direction while reciprocating the liquid ejection head H in the Y-axis direction and ejecting liquid from the liquid ejection head H toward the medium S in the +Z direction. The medium S can be made of any material, such as cloth, recording paper, or resin film. The direction in which the liquid ejection head H reciprocates is not limited to the Y-axis direction, but may be a direction inclined relative to both the X-axis and Y-axis directions. In this embodiment, the +Z direction is an example of the "ejection direction."

[0012] Such a liquid ejection device 1 includes a liquid ejection head H, a liquid storage section 3, a control device 4, a transport mechanism 5 that feeds out the medium S, and a moving mechanism 6.

[0013] The liquid ejection head H ejects liquid supplied from a liquid storage section 3 that stores the liquid as droplets in the +Z direction.

[0014] The liquid storage unit 3 individually stores multiple types of liquid with different colors and components to be ejected from the liquid ejection head H. Examples of the liquid storage unit 3 include a cartridge that is detachable from the liquid ejection device 1, a bag-shaped ink pack made of flexible film, and an ink tank that can be refilled with ink. FIG. 1 shows one liquid storage unit 3 as an example. The liquid storage unit 3 may be a liquid storage unit 3 having separate chambers that individually store multiple types of liquid, or may be multiple liquid storage units 3 provided individually for the multiple types of liquid. The liquid storage unit 3 may also be divided into a main tank and a sub-tank. The sub-tank may be connected to the liquid ejection head H, and the liquid consumed by ejecting droplets from the liquid ejection head H may be replenished from the main tank to the sub-tank.

[0015] The control device 4 comprehensively controls each element of the liquid ejection device 1, that is, the liquid ejection head H, the transport mechanism 5, the moving mechanism 6, and the like.

[0016] The transport mechanism 5 transports the medium S in the X-axis direction and has a transport roller 5a. The transport mechanism 5 transports the medium S in the X-axis direction by rotating the transport roller 5a. The transport roller 5a is rotated by driving a transport motor (not shown). The control device 4 controls the driving of the medium transport motor to control the transport of the medium S. Note that the transport mechanism 5 that transports the medium S is not limited to one that includes a transport roller 5a, and may transport the medium S by a belt or a drum, for example.

[0017] The movement mechanism 6 is a mechanism for reciprocating the liquid ejection head H in the Y-axis direction, and includes a holder 7 and a conveyor belt 8. The holder 7 is a so-called carriage that holds the liquid ejection head H, and is fixed to the conveyor belt 8. The conveyor belt 8 is an endless belt that is installed along the Y-axis direction. The conveyor belt 8 is rotated by driving a conveyor motor (not shown). The control device 4 controls the driving of the conveyor motor to rotate the conveyor belt 8, and moves the liquid ejection head H back and forth in the Y-axis direction together with the holder 7. The holder 7 may be configured to mount a liquid storage unit 3 together with the liquid ejection head H.

[0018] The liquid ejection head H performs an ejection operation in which the liquid supplied from the liquid storage unit 3 is ejected as droplets in the +Z direction from each of the multiple nozzles 21 (see FIG. 2) under the control of the control device 4. This ejection operation by the liquid ejection head H is performed in parallel with the transport of the medium S by the transport mechanism 5 and the reciprocating movement of the liquid ejection head H by the movement mechanism 6, thereby applying the liquid to the medium S, or so-called printing.

[0019] Fig. 2 is an exploded perspective view of the liquid ejection head H. Fig. 3 is a plan view of the pressure chamber substrate 10 when incorporated into the liquid ejection head H. Fig. 4 is a cross-sectional view of the liquid ejection head H taken along line AA' in Fig. 3. Fig. 5 is an enlarged view of the main part of Fig. 4. Note that the directions of the liquid ejection head H will be described based on the directions when it is mounted on the liquid ejection device 1, i.e., the X-axis direction, Y-axis direction, and Z-axis direction.

[0020] As shown in the figure, the liquid ejection head H of this embodiment comprises a pressure chamber substrate 10, a communicating plate 15, a nozzle plate 20 having a plurality of nozzles 21 formed therein, a protective substrate 30, a case member 40, a piezoelectric actuator 300, and a wiring member 110.

[0021] The pressure chamber substrate 10 is made of, for example, a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates. A plurality of pressure chambers 12 are arranged in a line along the X-axis direction in the pressure chamber substrate 10. The pressure chambers 12 are arranged on a straight line along the X-axis direction so as to be at the same position in the Y-axis direction. Two adjacent pressure chambers 12 in the X-axis direction are separated by a partition wall (not shown). In this embodiment, two pressure chamber rows are provided in the Y-axis direction, each row including the pressure chambers 12 arranged in a line along the X-axis direction. Of course, the arrangement of the pressure chambers 12 is not particularly limited thereto. For example, the pressure chambers 12 may be arranged in a staggered pattern along the X-axis direction. Here, 'arranging the pressure chambers 12 in a staggered pattern along the X-axis direction' means that the pressure chambers 12 arranged in a line along the X-axis direction are alternately shifted in the Y-axis direction. That is, two pressure chamber rows in which the pressure chambers 12 are arranged side by side in the X-axis direction are provided in the Y-axis direction, and the two pressure chamber rows are arranged offset from each other in the X-axis direction by half the pitch of the pressure chambers 12, i.e., half a pitch.

[0022] A communicating plate 15 and a nozzle plate 20 are sequentially stacked in the +Z direction on the surface of the pressure chamber substrate 10 facing the +Z direction. A vibration plate 50 and a piezoelectric actuator 300 are sequentially stacked in the -Z direction on the surface of the pressure chamber substrate 10 facing the -Z direction.

[0023] The communicating plate 15 is made of a plate-like member bonded to the surface of the pressure chamber substrate 10 facing the +Z direction. The communicating plate 15 is provided with nozzle communicating passages 16 that communicate between the pressure chambers 12 and the nozzles 21. The communicating plate 15 is also provided with a first manifold portion 17 and a second manifold portion 18 that constitute part of a manifold 100 that serves as a common liquid chamber through which a plurality of pressure chambers 12 communicate. The first manifold portion 17 is provided to penetrate the communicating plate 15 in the Z-axis direction. The second manifold portion 18 is provided to open on the surface facing the +Z direction without penetrating the communicating plate 15 in the Z-axis direction. The communicating plate 15 is also provided with supply communicating passages 19 that communicate with one end of the pressure chambers 12 in the Y-axis direction, independently for each pressure chamber 12. The supply communication passages 19 connect the second manifold portion 18 and the pressure chambers 12, supplying ink from the manifold 100 to the pressure chambers 12. In other words, the liquid ejection head H of this embodiment includes the supply communication passages 19, the pressure chambers 12, and the nozzle communication passages 16 as individual flow paths connected to the nozzles 21. The connecting plate 15 can be made of a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, or a metal substrate such as a stainless steel substrate. The connecting plate 15 is preferably made of a material having a linear expansion coefficient equivalent to that of the substrates bonded to the connecting plate 15, i.e., the pressure chamber substrate 10 and the nozzle plate 20, such as a silicon substrate or an SOI substrate. By using a material having a linear expansion coefficient equivalent to that of the substrates bonded to the connecting plate 15, the occurrence of peeling, cracks, and the like due to warping caused by differences in the linear expansion coefficients of the two can be suppressed.

[0024] The nozzle plate 20 is a plate-like member bonded to the side of the communication plate 15 opposite the pressure chamber substrate 10, i.e., the surface facing the +Z direction. The nozzle plate 20 has a plurality of nozzles 21 formed therein, which communicate with each pressure chamber 12 via nozzle communication passages 16. In this embodiment, the plurality of nozzles 21 are arranged in a line along the X-axis direction. Furthermore, in this embodiment, two nozzle rows, each with the nozzles 21 arranged side by side along the X-axis direction, are provided spaced apart in the Y-axis direction. A silicon substrate or an SOI substrate is preferably used for such a nozzle plate 20. However, the material of the nozzle plate 20 is not limited thereto, and a glass substrate, various ceramic substrates, or the like may also be used. In this embodiment, the surface of the nozzle plate 20 facing the +Z direction is referred to as a first surface 20a, and the surface facing the -Z direction is referred to as a second surface 20b.

[0025] The nozzles 21 eject ink droplets in the +Z direction. That is, the first surface 20a of the nozzle plate 20 serves as an ejection surface. The nozzles 21 also communicate with nozzle communication passages 16 that form individual flow paths in the -Z direction.

[0026] The nozzle 21 includes a first nozzle portion 22, a second nozzle portion 23, and a third nozzle portion 24. The first nozzle portion 22, the second nozzle portion 23, and the third nozzle portion 24 are arranged side by side in this order in the +Z direction. In other words, the second nozzle portion 23 is farther from the nozzle communicating passage 16 than the first nozzle portion 22, and the third nozzle portion 24 is farther from the nozzle communicating passage 16 than the second nozzle portion 23. In other words, the first nozzle portion 22 opens to the second surface 20b, and the third nozzle portion 24 opens to the first surface 20a. The second nozzle portion 23 is arranged between the first nozzle portion 22 and the third nozzle portion 24.

[0027] On the side walls of the first nozzle portion 22, a plurality of first grooves 22a are formed side by side in the +Z direction. Also, on the side walls of the second nozzle portion 23, a plurality of second grooves 23a are formed side by side in the +Z direction. Further, on the side walls of the third nozzle portion 24, a plurality of third grooves 24a are formed side by side in the +Z direction. These first grooves 22a, second grooves 23a, and third grooves 24a are each composed of scallops. Here, a scallop refers to a shape in which when a through hole or a recess is formed in a silicon substrate by a Bosch process, a waveform shape as observed on the surface of a shell is formed on the side wall of the through hole or the recess, that is, a shape in which a plurality of grooves are formed. The Bosch process is a method of forming a substantially vertical through hole or recess by alternately repeating an etching step of performing isotropic etching mainly using sulfur hexafluoride or the like and a protection step of protecting the side wall using a CF-based gas or the like.

[0028] Here, the inner diameter R3 of the third nozzle portion 24 is smaller than the inner diameter R2 of the second nozzle portion 23. That is, the inner diameter R3 of the third nozzle portion 24 and the inner diameter R2 of the second nozzle portion 23 satisfy the relationship R3 < R2. Note that the inner diameter R2 of the second nozzle portion 23 in the present embodiment refers to the inner diameter of the smallest portion formed by the plurality of second grooves 23a. Also, the inner diameter R3 of the third nozzle portion 24 refers to the inner diameter of the smallest portion formed by the plurality of third grooves 24a. Note that the inner diameters of the second nozzle portion 23 and the third nozzle portion 24 may be the inner diameters of the largest portions, respectively. Also, the inner diameters of the second nozzle portion 23 and the third nozzle portion 24 may be intermediate values between the smallest inner diameter and the largest inner diameter, respectively. Also, the inner diameters of the second nozzle portion 23 and the third nozzle portion 24 may be average values of the inner diameters measured at several locations in the +Z direction or the like.

[0029] The width W1 in the +Z direction of each of the plurality of first grooves 22a is larger than the width W2 in the +Z direction of each of the plurality of second grooves 23a. In other words, the width W1 of the first grooves 22a and the width W2 of the second grooves 23a satisfy the relationship W1>W2. Note that the width W1 may be the average value of the widths of the plurality of first grooves 22a, or may be the mode or median value of all the first grooves 22a. The same applies to the width W2. Of course, the width W1 of the first grooves 22a is smaller than the width W2 of the second grooves 23a, that is, W1 <W2であってもよい。

[0030] In this way, by making the width W1 per one of the first grooves 22a of the first nozzle portion 22 connected to the nozzle communicating passage 16 larger than the width W2 per one of the second grooves 23a of the second nozzle portion 23, foreign matter such as air bubbles, dust, or thickened ink that has entered the first groove 22a from the nozzle communicating passage 16 is likely to flow out of the first groove 22a. In other words, if the width W1 of the first groove 22a is larger than the width W2 of the second groove 23a, the flow of ink is less likely to stagnate in the first groove 22a than in the second groove 23a, and foreign matter that has entered the first groove 22a is less likely to remain in the first groove 22a than in the second groove 23a. This prevents foreign matter that has entered the first groove 22a from remaining there and clogging it, which can change the shape of the first nozzle portion 22 when viewed from the +Z direction, making it impossible to obtain desired ink ejection characteristics. Note that foreign matter entering the nozzle 21 from the nozzle communicating passage 16 significantly affects the portion of the nozzle 21 that is close to the nozzle communicating passage 16. That is, because the inner diameter of the nozzle 21 decreases from the first nozzle portion 22 and the second nozzle portion 23 toward the third nozzle portion 24, the flow rate is greater in the third nozzle portion 24 than in the first nozzle portion 22 and the second nozzle portion 23. Therefore, if foreign matter does not clog the first groove 22a of the first nozzle portion 22, the foreign matter is unlikely to clog the second groove 23a and the third groove 24a of the second nozzle portion 23 and the third nozzle portion 24. Furthermore, because a step is formed between the second nozzle portion 23 and the third nozzle portion 24 due to the difference in inner diameter, the ink in the first nozzle portion 22 and the second nozzle portion 23 flows into the third nozzle portion 24, and the ink that does not flow into the third nozzle portion 24 flows back toward the nozzle communicating passage 16. Therefore, foreign matter that does not clog first nozzle portion 22 is less likely to clog second groove 23a and third groove 24a due to a flow that flows back into nozzle communicating passage 16. Therefore, by providing first nozzle portion 22 having first groove 22a on the nozzle communicating passage 16 side of nozzle 21, which is the side most susceptible to clogging with foreign matter, foreign matter is less likely to clog the side walls within nozzle 21.

[0031] It is preferable that the length L1 of the first nozzle portion 22 along the +Z direction be shorter than the length L2 of the second nozzle portion 23 along the +Z direction. As described above, it is sufficient to provide the first nozzle portion 22 only on the side of the nozzle communication passage 16 that is most susceptible to clogging with foreign matter, and as will be described in detail later, with respect to the second nozzle portion 23 that controls the length of the third nozzle portion 24 in the +Z direction, it is necessary to control the length of the second nozzle portion 23 in the +Z direction with high precision by making the width of the second groove 23a relatively narrow. It is also preferable that the length L1 of the first nozzle portion 22 be approximately 1 / 5 of the combined length of the first nozzle portion 22 and the second nozzle portion 23, i.e., L1 + L2.

[0032] The lengths L1+L2 of the first nozzle portion 22 and the second nozzle portion 23 need to be controlled with high precision in order to control the length of the third nozzle portion 24 in the +Z direction with high precision using a manufacturing method described in detail below. However, to control the length of the third nozzle portion 24, the length of the second nozzle portion 23 needs to be controlled with high precision. In other words, high precision control of the first nozzle portion 22 is not required in order to control the length of the third nozzle portion 24. For this reason, the width W1 of the first groove 22a of the first nozzle portion 22 is made larger than the width W2 of the second groove 23a of the second nozzle portion 23. In other words, among the etching conditions for forming the first nozzle portion 22 and the second nozzle portion 23, the etching rate for forming the first nozzle portion 22 is made larger than the etching rate for forming the second nozzle portion 23, thereby shortening the manufacturing time required to form the nozzle 21. Furthermore, by making the width W2 of the second groove 23a of the second nozzle portion 23 narrower than the width W1 of the first groove 22a, in other words, by making the etching rate when forming the second nozzle portion 23 smaller than the etching rate when forming the first nozzle portion 22 among the etching conditions when forming the first nozzle portion 22 and the second nozzle portion 23, it is possible to control the length L2 of the second nozzle portion 23 with high precision, and therefore the length of the third nozzle portion 24 can be controlled with high precision, and a high-precision nozzle 21 can be manufactured.

[0033] In this embodiment, the width H1 of each of the plurality of first grooves 22a along the radial direction of the nozzle 21 is greater than the width H2 of each of the plurality of second grooves 23a along the radial direction of the nozzle 21. The radial direction of the nozzle 21 is a direction perpendicular to the +Z direction, which is the ejection direction, that is, a direction along the XY plane defined by the X-axis and the Y-axis. The width H1 of the first groove 22a and the width H2 of the second groove 23a satisfy the relationship H1 > H2. This, as with the relationship between the widths W1 and W2 described above, makes it easier for ink to flow in the first groove 22a than in the second groove 23a, and foreign matter such as air bubbles, dust, and ink thickeners that have entered from the nozzle communication passage 16 is less likely to clog the first groove 22a than in the second groove 23a.

[0034] Furthermore, the inner diameter R1 of the first nozzle portion 22 is larger than the inner diameter R2 of the second nozzle portion 23. In other words, the relationship between the inner diameter R1 of the first nozzle portion 22 and the inner diameter R2 of the second nozzle portion 23 satisfies the relationship R1>R2. The inner diameter R1 of the first nozzle portion 22 and the inner diameter R2 of the second nozzle portion 23 are the same as the inner diameter R2 of the second nozzle portion 23 and the inner diameter R3 of the third nozzle portion 24 described above. By making the inner diameter R1 of the first nozzle portion 22 larger than the inner diameter R2 of the second nozzle portion 23 in this way, the inner diameter can be gradually increased from the second nozzle portion 23 toward the first nozzle portion 22, which communicates with the nozzle communicating passage 16. This makes it easier for foreign matter, such as air bubbles, dust, and thickened ink, that has entered the nozzles 21 from the nozzle communicating passage 16 to return to the nozzle communicating passage 16. Therefore, by making the inner diameter R1 of the first nozzle portion 22 larger than the inner diameter R2 of the second nozzle portion 23, foreign matter is less likely to clog the first groove 22a.

[0035] Furthermore, the width W3 in the +Z direction of the third groove 24a of the third nozzle portion 24 is preferably the same as the width W1 of the first groove 22a of the first nozzle portion 22. This is because the same etching conditions can be used when forming the first nozzle portion 22 and the second nozzle portion 23 using the same Bosch process, simplifying the control of the etching apparatus. Hereinafter, the etching conditions refer to the etching rate and etching time. The same etching conditions refer to both the same etching rate and etching time. Different etching conditions refer to different etching rates or etching times. The etching rate is determined by the intensity of the plasma power source, the flow rate of the etching gas, and the process pressure. The etching time refers to the time required for one etching step in the Bosch process. The width W1 of the first groove 22a and the width W3 of the third groove 24a being the same also refers to dimensional variations that occur when etching is performed using the same etching apparatus under the same etching conditions, such as a ±10% error between the widths W1 and W2. Of course, the width W3 of the third grooves 24a may be larger or smaller than the width W1 of the first grooves 22a. If the width W3 of the third grooves 24a is larger than the width W1 of the first grooves 22a, the widths W3 of the multiple third grooves 24a may vary, making it difficult to form them with high precision. Furthermore, if the width W3 of the third grooves 24a is smaller than the width W1 of the first grooves 22a, it takes a long time to form them. Therefore, by setting the width W3 of the third grooves 24a to be the same as the width W1 of the first grooves 22a, they can be formed with relatively high precision and in a short time.

[0036] Also, in the present embodiment, the width H2 along the radial direction of the nozzle 21 per one of the plurality of second grooves 23a is smaller than the width H3 along the radial direction of the nozzle 21 per one of the plurality of third grooves 24a. And the width H2 of the second groove 23a and the width H3 of the third groove 24a satisfy the relationship of H2 < H3. That is, the width H3 of the third groove 24a is larger than the width H2 of the second groove 23a. For this reason, the ink flows more easily in the third groove 24a than in the second groove 23a, it is difficult for foreign matter to clog in the third groove 24a, and it is possible to suppress the shape of the third nozzle portion 24 from being deformed by the clogged ink. For this reason, in particular, it is possible to suppress the shape of the third nozzle portion 24, which affects the ink ejection characteristics, from changing, and to obtain desired ink ejection characteristics.

[0037] Also, a protective film (not shown) is formed on the surface of the nozzle plate 20, that is, on the first surface, the second surface, and the wall surface of the nozzle 21. The protective film may be a silicon oxide film formed by thermally oxidizing the nozzle plate 20, or may be a film formed of other materials. Further, a liquid repellent film (not shown) is formed on the surface of the nozzle plate 20 in the +Z direction.

[0038] The diaphragm 50 has, for example, an elastic film 51 made of silicon oxide provided on the pressure chamber substrate 10 side, and an insulator film 52 made of zirconium oxide provided on the surface of the elastic film 51 facing the -Z direction.

[0039] The piezoelectric actuator 300 includes a first electrode 60 sequentially stacked in the -Z direction on the diaphragm 50, a piezoelectric layer 70 formed using a piezoelectric material, for example, a composite oxide with a perovskite structure represented by the general formula ABO3, and a second electrode 80. Such a piezoelectric actuator 300 is also referred to as a piezoelectric element, and refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. Furthermore, a portion of the piezoelectric layer 70 where piezoelectric strain occurs when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In contrast, a portion of the piezoelectric layer 70 where no piezoelectric strain occurs is referred to as an inactive portion. In other words, the active portion 310 refers to the portion of the piezoelectric layer 70 sandwiched between the first electrode 60 and the second electrode 80. In this embodiment, an active portion 310 is formed for each pressure chamber 12. In other words, the piezoelectric actuator 300 is formed with multiple active portions 310. The plurality of active portions 310 serve as driving elements that cause pressure changes in the ink within the pressure chambers 12. Generally, one of the electrodes of the active portions 310 is configured as an individual electrode that is independent for each active portion 310, and the other electrode is configured as a common electrode that is common to the plurality of active portions 310. In this embodiment, the first electrode 60 constitutes the individual electrode, and the second electrode 80 constitutes the common electrode.

[0040] Furthermore, individual lead electrodes 91, which are lead wiring, are led out from the first electrode 60. Furthermore, a common lead electrode 92, which is also lead wiring, is led out from the second electrode 80. A wiring member 110 made of a flexible substrate is connected to the ends of these individual lead electrodes 91 and the common lead electrode 92 opposite to the ends connected to the piezoelectric actuator 300. The wiring member 110 is mounted with a drive circuit 111 having a plurality of switching elements that select whether or not to supply a drive signal for driving each of the active portions 310 to each active portion 310. In other words, the wiring member 110 in this embodiment is a COF (Chip On Film). Note that the wiring member 110 does not necessarily have to be provided with the drive circuit 111. In other words, the wiring member 110 may be an FFC (Flexible Flat Cable), an FPC (Flexible Printed Circuits), or the like.

[0041] A protective substrate 30 having approximately the same size as the pressure chamber substrate 10 is bonded to the surface of the pressure chamber substrate 10 facing the -Z direction. The protective substrate 30 has accommodation sections 31, which are spaces for protecting the piezoelectric actuators 300. The accommodation sections 31 are provided independently for each row of piezoelectric actuators 300 arranged side by side in the X-axis direction, with two accommodation sections 31 formed side by side in the Y-axis direction. The protective substrate 30 also has a through hole 32 penetrating in the Z-axis direction between the two accommodation sections 31 arranged side by side in the Y-axis direction. Ends of lead electrodes 91 drawn from each electrode of the piezoelectric actuators 300 extend so as to be exposed within the through hole 32, and the lead electrodes 91 and the wiring member 110 are electrically connected within the through hole 32. Such a protective substrate 30 may be made of, for example, a silicon substrate.

[0042] In addition, a case member 40 that defines a manifold 100 that communicates with the multiple pressure chambers 12 is fixed on the protective substrate 30. The case member 40 has substantially the same shape as the above-mentioned communicating plate 15 in a plan view, and is bonded to the protective substrate 30 as well as to the above-mentioned communicating plate 15.

[0043] Such a case member 40 has a recess 41 on the protective substrate 30 side that is deep enough to accommodate the pressure chamber substrate 10 and the protective substrate 30. This recess 41 has an opening area that is larger than the surface of the protective substrate 30 that is bonded to the pressure chamber substrate 10. Then, with the pressure chamber substrate 10 and the protective substrate 30 accommodated in the recess 41, the opening surface of the recess 41 on the nozzle plate 20 side is sealed by the communicating plate 15.

[0044] The case member 40 is also provided with a third manifold portion 42 that communicates with the first manifold portion 17 of the communication plate 15. The first manifold portion 17 and the second manifold portion 18 that are provided in the communication plate 15 and the third manifold portion 42 that is provided in the case member 40 constitute a manifold 100 of this embodiment. A total of two manifolds 100 are provided, one for each row of the pressure chambers 12. Each manifold 100 is provided continuously along the X-axis direction in which the pressure chambers 12 are arranged side by side, and the supply communication passages 19 that communicate between each pressure chamber 12 and the manifold 100 are arranged side by side in the X-axis direction. The case member 40 is also provided with an inlet port 44 that communicates with the manifold 100 and supplies ink to each manifold 100. The case member 40 is also provided with a connection port 43 that communicates with the through-hole 32 of the protection substrate 30 and through which the wiring member 110 is inserted. The case member 40 is made of a material such as a metal material or a resin material.

[0045] Furthermore, a compliance substrate 45 is provided on the surface of the communicating plate 15 on the +Z direction side where the first manifold portion 17 and the second manifold portion 18 open. This compliance substrate 45 seals the openings on the ejection surface side of the first manifold portion 17 and the second manifold portion 18. In this embodiment, such compliance substrate 45 includes a sealing film 46 made of a flexible thin film, and a fixed substrate 47 made of a hard material such as metal. The region of the fixed substrate 47 facing the manifold 100 is an opening 48 that is completely removed in the thickness direction, and therefore one surface of the manifold 100 forms a compliance portion 49 that is a flexible portion sealed only by the flexible sealing film 46.

[0046] In such a liquid ejection head H, liquid is taken into the manifold 100 from the liquid storage section 3 via the inlet 44, filling the interior from the manifold 100 to the nozzles 21, and then a voltage is applied to each active section 310 corresponding to the pressure chambers 12 in accordance with a recording signal from the drive circuit 111. This causes the diaphragm 50 to flex and deform together with the active section 310, increasing the pressure of the liquid in each pressure chamber 12 and causing droplets to be ejected from each nozzle 21.

[0047] A method for manufacturing the nozzle plate 20 of the liquid ejection head H of this embodiment will be described. Fig. 6 is a flowchart showing a method for manufacturing the liquid ejection head H. Figs. 7 to 11 are cross-sectional views of the nozzle plate 20 illustrating the method for manufacturing the liquid ejection head H.

[0048] 7, in step S1, a mask film 120 is formed on the first surface 20a of the nozzle plate 20, and an opening 121 is formed in the mask film 120 by photolithography. The opening 121 is formed so as to open an area where the third nozzle portion 24 is to be formed.

[0049] Next, in step S2, as shown in Fig. 8, the nozzle plate 20 is subjected to a Bosch process from the first surface 20a side, thereby performing a first process of forming a recess 124 having a third groove 24a formed in its side wall. The recess 124 will become the third nozzle portion 24 in a later process, and is formed longer in the +Z direction than the third nozzle portion 24. In this way, by forming the recess 124 without penetrating the nozzle plate 20 in the +Z direction, the time required for the Bosch process can be shortened. Of course, the recess 124 may also be a through-hole provided so as to penetrate the nozzle plate 20 in the Z-axis direction.

[0050] Next, in step S3, the mask film 120 on the first surface 20a of the nozzle plate 20 is removed. 9, a mask film 130 is formed on the second surface 20b of the nozzle plate 20, and an opening 131 is formed in the mask film 130 by photolithography. The opening 131 is formed so as to open the region where the first nozzle portion 22 is to be formed.

[0051] Next, in step S5, as shown in FIG. 10 , a second process is performed in which the nozzle plate 20 is subjected to a Bosch process from the second surface 20b side using a mask film 130 to form a first nozzle portion 22 having a first groove 22a formed in its sidewall. In this embodiment, the Bosch process for forming the first nozzle portion 22 is performed under the same etching conditions as the Bosch process for forming the third nozzle portion 24. As described above, the etching conditions refer to the etching rate and etching time. The same etching conditions refer to both the same etching rate and etching time. Different etching conditions refer to at least one of the different etching rates and etching times. The etching rate is determined by the intensity of the plasma power source, the flow rate of the etching gas, and the process pressure. The etching time refers to the time required for one etching step in the Bosch process. Forming the first nozzle portion 22 and the third nozzle portion 24 under the same etching conditions facilitates etching control compared to forming the first groove 22a and the third groove 24a under different etching conditions. The first groove 22a and the third groove 24a formed under the same etching conditions have the same width in the +Z direction. Furthermore, by setting the etching rate of the first nozzle portion 22 and the third nozzle portion 24 to be higher than the etching rate for forming the second nozzle portion 23 (described later), the time required to form the first nozzle portion 22 and the third nozzle portion 24 can be shortened, thereby shortening the manufacturing time for the nozzle 21. In other words, the third nozzle portion 24 could be formed at the same etching rate as the second nozzle portion 23 (described later), but the time required to form the second nozzle portion 23 would increase the manufacturing time for the nozzle 21. However, by forming the third nozzle portion 24 at the same etching rate as the second nozzle portion 23, it is not necessary to increase the strength of the plasma power source, the flow rate of the etching gas, or the process pressure, thereby reducing power consumption. Of course, the first nozzle portion 22 and the third nozzle portion 24 may be formed at different etching rates or different etching times.

[0052] Next, in step S6, as shown in FIG. 11 , a third process is performed on the nozzle plate 20 from the second surface 20b side using a mask film 130, in which the Bosch process is performed until a portion of the recess 124 is reached. In the third process, a second nozzle portion 23 having a second groove 23a formed in its sidewall is formed, and a third nozzle portion 24 is formed in the remaining portion of the recess 124. The Bosch process for forming the second nozzle portion 23 is performed under different etching conditions than the Bosch process for forming the first nozzle portion 22. As described above, the etching conditions refer to the etching rate and etching time. Different etching conditions mean that at least one of the etching rate and etching time is different. For example, the etching rate for forming the second nozzle portion 23 is set lower than the etching rate for forming the first nozzle portion 22. In this case, the time required to form the second nozzle portion 23 is longer than when the second nozzle portion 23 is formed at the same etching rate as the first nozzle portion 22. In other words, the Bosch process for forming the first nozzle portion 22 is performed at a higher etching rate than the Bosch process for forming the second nozzle portion 23. This allows the width W1 of the first groove 22a to be greater than the width W2 of the second groove 23a, and the height H1 of the first groove 22a to be greater than the height H2 of the second groove 23a (see FIG. 5). Also, the inner diameter R1 of the first nozzle portion 22 can be greater than the inner diameter R2 of the second nozzle portion 23 (see FIG. 5).

[0053] Alternatively, the etching rate for forming second nozzle portion 23 is the same as the etching rate for forming first nozzle portion 22, and the etching time for one etching step for forming second nozzle portion 23 is set shorter than the etching time for forming first nozzle portion 22. That is, the etching time for one etching step for forming first nozzle portion 22 is set longer than the etching time for forming second nozzle portion 23. This also makes it possible to make width W1 of first groove 22a larger than width W2 of second groove 23a, and to make height H1 of first groove 22a larger than height H2 of second groove 23a (see FIG. 5). Also, it makes it possible to make inner diameter R1 of first nozzle portion 22 larger than inner diameter R2 of second nozzle portion 23 (see FIG. 5).

[0054] Furthermore, forming the second nozzle portion 23 removes a portion of the recess 124, and the remaining portion of the recess 124 becomes the third nozzle portion 24. In other words, forming the second nozzle portion 23 determines the length of the third nozzle portion 24 in the +Z direction. Therefore, by etching the second nozzle portion 23 at an etching rate that relatively reduces the width of the second groove 23a, the length of the second nozzle portion 23 in the +Z direction can be controlled with high precision, and the length of the third nozzle portion 24 in the +Z direction can be formed with high precision. In other words, if the first nozzle portion 22 and the second nozzle portion 23 are formed with the same width W1, the precision of the length of the third nozzle portion 24 in the +Z direction will decrease. Because the length of the third nozzle portion 24 in the +Z direction significantly affects the ejection characteristics, such as the ink flight speed and weight, a decrease in the precision of the length of the third nozzle portion 24 in the +Z direction will make it difficult to obtain desired ejection characteristics. In this embodiment, the second nozzle portion 23 can be formed with high precision, thereby improving the precision of the length of the third nozzle portion 24 in the +Z direction, and therefore, desired ejection characteristics can be obtained.

[0055] In this embodiment, the second and third steps are performed using the Bosch process using the same mask film 130. This simplifies the manufacturing process and reduces the manufacturing time compared to when different mask films are used in the second and third steps. Of course, different mask films may be used in the second and third steps.

[0056] After the nozzles 21 are formed in this manner, the mask film 130 is removed in step S7. Thereafter, a protective film and a water-repellent film (not shown) are formed on the surface of the nozzle plate 20, thereby manufacturing the nozzle plate 20.

[0057] As described above, in the manufacturing method of the liquid ejection head H of this embodiment, the first nozzle portion 22 and the second nozzle portion 23 are formed using the same mask film 130, which eliminates the need for separate mask films for forming the first nozzle portion 22 and the second nozzle portion 23, thereby reducing the number of steps and lowering costs. Furthermore, the first nozzle portion 22 and the second nozzle portion 23 can be easily formed simply by changing the etching rate.

[0058] Furthermore, the lengths L1+L2 of the first nozzle portion 22 and the second nozzle portion 23 require high-precision length control to accurately control the length of the third nozzle portion 24 in the +Z direction. However, to control the length of the third nozzle portion 24, the length of the second nozzle portion 23 must be controlled with high precision. In other words, high-precision control of the first nozzle portion 22 is not required to control the length of the third nozzle portion 24. Therefore, the manufacturing time required to form the nozzle 21 can be shortened by increasing the etching rate, which is an etching condition when forming the first nozzle portion 22 using the Bosch process. Alternatively, the first nozzle portion 22 can be formed using the same etching rate as the second nozzle portion 23 using the Bosch process, and the etching time, which is an etching condition. In this case, since there is no need to increase the etching rate, there is no need to increase the intensity of the plasma power source, the flow rate of the etching gas, or the process pressure, and power consumption can be reduced. Furthermore, by setting the etching rate, which is an etching condition when forming second nozzle portion 23 by the Bosch process, to a relatively small value, it is possible to control length L2 of second nozzle portion 23 with high precision, and therefore it is possible to control the length of third nozzle portion 24 with high precision, and it is possible to manufacture a high-precision nozzle 21.

[0059] (Other embodiments) Although one embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above.

[0060] For example, in the first embodiment described above, the liquid ejection head is manufactured by first forming the recess 124 that will become the third nozzle portion 24 on the first surface 20a of the nozzle plate 20 by the Bosch process, and then forming the first nozzle portion 22 and the second nozzle portion 23 on the second surface 20b of the nozzle plate 20 by the Bosch process. However, the method is not particularly limited to this. For example, the first nozzle portion 22 and the second nozzle portion 23 may be formed on the second surface 20b first, and then the third nozzle portion 24 may be formed on the first surface 20a. Even in such a case, the length of the third nozzle portion 24 is controlled by controlling the length of the second nozzle portion 23 in the +Z axis direction that was formed first. Therefore, by making the width W2 of the second groove 23a of the second nozzle portion 23 smaller than the first width 22a of the first nozzle portion 22, the length of the second nozzle portion 23 in the +Z direction can be controlled with high precision, and the length of the third nozzle portion 24 in the +Z direction can be formed with high precision.

[0061] Furthermore, in the above-described first embodiment, a configuration has been exemplified in which the nozzles 21 communicate with the pressure chambers 12 via the nozzle communication paths 16, but the configuration is not particularly limited to this. For example, in a configuration in which the pressure chamber substrate 10 and the nozzle plate 20 are directly bonded together without providing the communication plate 15, the pressure chambers 12 and the nozzles 21 may communicate directly with each other. In such a configuration in which the pressure chamber substrate 10 and the nozzle plate 20 are directly bonded together, at least a part of the supply paths and manifolds may be formed in the pressure chamber substrate 10, or the supply paths and manifolds may be formed in a member other than the pressure chamber substrate 10.

[0062] In the first embodiment described above, the thin-film piezoelectric actuator 300 is used as the driving element for generating a pressure change in the pressure chamber 12. However, the present invention is not limited to this, and the driving element may be, for example, a thick-film piezoelectric actuator formed by attaching a green sheet or a longitudinal vibration type piezoelectric actuator in which piezoelectric material and electrode forming material are alternately laminated and expanded and contracted in the axial direction. The driving element may be, for example, a device in which a heating element is disposed in the pressure chamber 12 and bubbles generated by the heat generated by the heating element are used to eject droplets from the nozzle 21, or a so-called electrostatic actuator in which static electricity is generated between a vibration plate and an electrode, and the electrostatic force deforms the vibration plate, causing droplets to be ejected from the nozzle 21.

[0063] Furthermore, in the above-described liquid ejection device 1, an example was given in which the liquid ejection head H is mounted on a holder 7 and moves in the main scanning direction, but this is not particularly limited to this, and the present invention can also be applied to, for example, a so-called line-type recording device in which the liquid ejection head H is fixed and printing is performed simply by moving a medium S such as paper in the sub-scanning direction.

[0064] Furthermore, the present invention is broadly applicable to liquid ejection devices in general that include a liquid ejection head. Examples of liquid ejection heads include various inkjet recording heads used in image recording devices such as printers, and colorant ejection heads used in the manufacture of color filters for liquid crystal displays and the like. Examples of liquid ejection heads include electrode material ejection heads used in the formation of electrodes for organic EL displays, FEDs (field emission displays), and the like, and bioorganic material ejection heads used in the manufacture of biochips, and the present invention can also be applied to liquid ejection devices that include these liquid ejection heads.

[0065] (Addendum) From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0066] A liquid ejection head according to Aspect 1, which is a preferred aspect, is a liquid ejection head having a nozzle that ejects liquid and individual flow paths including pressure chambers that apply pressure to eject liquid from the nozzle, wherein the nozzle includes a first nozzle portion, a second nozzle portion that is farther from the individual flow path in the ejection direction than the first nozzle portion, and a third nozzle portion that is farther from the individual flow path in the ejection direction than the second nozzle portion and has a smaller diameter than the second nozzle portion, wherein a side wall of the first nozzle portion has a plurality of first grooves aligned in the ejection direction, and a side wall of the second nozzle portion has a plurality of second grooves aligned in the ejection direction, and a width of each of the plurality of first grooves along the ejection direction is greater than a width of each of the plurality of second grooves along the ejection direction. This makes it easier for liquid to flow through the first grooves than through the second grooves, and makes it less likely for foreign matter such as air bubbles, dust, and thickened substances contained in the liquid to clog the first grooves. Therefore, it is possible to prevent the nozzle shape from being deformed by foreign matter lodged in the groove, and to prevent the ejection characteristics of droplets ejected from the nozzle from being deteriorated.

[0067] In Aspect 2, which is a specific example of Aspect 1, the radial width of each of the plurality of first grooves is greater than the radial width of each of the plurality of second grooves, which also facilitates the flow of liquid within the first groove and makes it difficult for foreign matter to clog the first groove.

[0068] In Aspect 3, which is a specific example of Aspect 1, the sidewall of the third nozzle portion has a plurality of third grooves aligned in the discharge direction, and the width of each of the plurality of second grooves along the discharge direction is smaller than the width of each of the plurality of third grooves along the discharge direction. This makes it easier for liquid to flow through the third grooves than through the second grooves, making it less likely for foreign matter to clog the third grooves.

[0069] In Aspect 4, which is a specific example of Aspect 3, the radial width of each of the plurality of second grooves is smaller than the radial width of each of the plurality of third grooves. This allows the length of the second nozzle portion in the discharge direction, which determines the length of the third nozzle portion in the discharge direction, to be controlled with high precision, thereby allowing the length of the third nozzle portion in the discharge direction to be formed with high precision.

[0070] In Aspect 5, which is a specific example of Aspect 3, the width of each of the plurality of first grooves along the discharge direction is the same as the width of each of the plurality of third grooves along the discharge direction. This allows the first nozzle portion and the third nozzle portion to be manufactured under the same etching conditions, making it easier to control the etching apparatus during manufacturing and simplifying the manufacturing process.

[0071] In Aspect 6, which is a specific example of Aspect 1, the length of the first nozzle portion along the discharge direction is shorter than the length of the second nozzle portion along the discharge direction. Thus, by designating only the portion on the individual flow path side, where foreign matter is likely to be mixed in, as the first nozzle portion, foreign matter is less likely to clog the first nozzle portion, and by making the second nozzle portion, which determines the length of the third nozzle portion, relatively long, the length of the third nozzle portion can be controlled with high precision.

[0072] A liquid ejection device according to a preferred aspect 7 includes the liquid ejection head according to any one of the above aspects, thereby realizing a liquid ejection device that prevents foreign matter from clogging the nozzles and prevents deterioration of ejection characteristics.

[0073] A preferred embodiment of a manufacturing method for a liquid ejection head according to an eighth aspect is a method for manufacturing a liquid ejection head, the method comprising: a nozzle plate provided with nozzles that eject liquid; and individual flow paths including pressure chambers that apply pressure for ejecting liquid from the nozzles, the nozzles including a first nozzle portion, a second nozzle portion that is farther from the individual flow path in the ejection direction than the first nozzle portion, and a third nozzle portion that is farther from the individual flow path in the ejection direction than the second nozzle portion and has a smaller diameter than the second nozzle portion; a side wall of the first nozzle portion has a plurality of first grooves aligned in the ejection direction; a side wall of the second nozzle portion has a plurality of second grooves aligned in the ejection direction; and a width of each of the plurality of first grooves along the ejection direction is larger than a width of each of the plurality of second grooves along the ejection direction, The method includes a first step of performing a Bosch process from one surface side of the nozzle plate to form a recess that is longer in the discharge direction than the third nozzle portion; a second step of performing a Bosch process from the other surface side of the nozzle plate after the first step to form the first nozzle portion, whose side wall has the plurality of first grooves aligned in the discharge direction; and a third step of performing a Bosch process from the other surface side of the nozzle plate to a part of the recess, after the second step, to form the second nozzle portion, whose side wall has the plurality of second grooves aligned in the discharge direction, and the third nozzle portion with the remaining part of the recess, wherein the second step and the third step use different etching conditions to make the width of each of the plurality of first grooves in the discharge direction larger than the width of each of the plurality of second grooves in the discharge direction.

[0074] This makes it possible to reduce the time required to form the first nozzle portion, and also to form the second nozzle portion with high precision, thereby enabling the length of the third nozzle portion to be formed with high precision. [Explanation of symbols]

[0075] S...medium, 1...liquid ejection device, 3...liquid storage section, 4...control device, 5...transport mechanism, 6...movement mechanism, 7...holding body, 8...transport belt, 10...pressure chamber substrate, 12...pressure chamber, 15...communication plate, 16...nozzle communication passage, 17...first manifold section, 18...second manifold section, 19...supply communication passage, 20...nozzle plate, 20a...first surface, 20b...second surface, 21...nozzle, 22...first nozzle section, 22a...first groove, 23... Second nozzle portion, 23a...second groove, 24...third nozzle portion, 24a...third groove, 30...protective substrate, 40...case member, 45...compliance substrate, 50...diaphragm, 60...first electrode, 70...piezoelectric layer, 80...second electrode, 100...manifold, 110...wiring member, 111...drive circuit, 120, 130...mask film, 121, 131...opening, 124...recess, 300...piezoelectric actuator, 310...active portion.

Claims

1. a nozzle for discharging a liquid; an individual flow path including a pressure chamber that applies pressure for ejecting liquid from the nozzle; A liquid ejection head having The nozzle is a first nozzle portion; a second nozzle portion that is farther from the individual flow path than the first nozzle portion in a discharge direction; a third nozzle portion that is farther from the individual flow path than the second nozzle portion in the discharge direction and has a smaller diameter than the second nozzle portion, a sidewall of the first nozzle portion has a plurality of first grooves arranged in the ejection direction; a sidewall of the second nozzle portion has a plurality of second grooves arranged in the ejection direction; a width of each of the plurality of first grooves along the discharge direction is greater than a width of each of the plurality of second grooves along the discharge direction; A liquid ejection head characterized by:

2. a width of each of the plurality of first grooves along the radial direction is greater than a width of each of the plurality of second grooves along the radial direction; 2. The liquid ejection head according to claim 1.

3. a sidewall of the third nozzle portion has a plurality of third grooves aligned in the ejection direction; a width of each of the plurality of second grooves along the discharge direction is smaller than a width of each of the plurality of third grooves along the discharge direction; 2. The liquid ejection head according to claim 1.

4. a width of each of the plurality of second grooves along the radial direction is smaller than a width of each of the plurality of third grooves along the radial direction; 4. The liquid ejection head according to claim 3.

5. a width of each of the plurality of first grooves along the discharge direction is the same as a width of each of the plurality of third grooves along the discharge direction; 4. The liquid ejection head according to claim 3.

6. a length of the first nozzle portion along the ejection direction is shorter than a length of the second nozzle portion along the ejection direction; 2. The liquid ejection head according to claim 1.

7. A liquid ejection head according to any one of claims 1 to 6, A liquid ejection device characterized by:

8. a nozzle plate provided with nozzles for discharging liquid; an individual flow path including a pressure chamber that applies pressure for ejecting liquid from the nozzle; and The nozzle is a first nozzle portion; a second nozzle portion that is farther from the individual flow path than the first nozzle portion in a discharge direction; a third nozzle portion that is farther from the individual flow path than the second nozzle portion in the discharge direction and has a smaller diameter than the second nozzle portion; Including, a sidewall of the first nozzle portion has a plurality of first grooves arranged in the ejection direction; a sidewall of the second nozzle portion has a plurality of second grooves arranged in the ejection direction; a width of each of the plurality of first grooves along the discharge direction is greater than a width of each of the plurality of second grooves along the discharge direction; A method for manufacturing a liquid ejection head, comprising: a first step of performing a Bosch process from one surface side of the nozzle plate to form a recess that is longer in the ejection direction than the third nozzle portion; a second step of performing a Bosch process from the other surface side of the nozzle plate after the first step to form the first nozzle portion in which the plurality of first grooves are aligned in the ejection direction on a side wall of the nozzle plate; a third step of performing a Bosch process from the other surface side of the nozzle plate to a part of the recessed portion after the second step to form the second nozzle portion having the plurality of second grooves aligned in the ejection direction on a side wall thereof and the third nozzle portion in the remaining part of the recessed portion; Equipped with the second step and the third step use the same mask film but under different etching conditions, so that the width of each of the plurality of first grooves along the discharge direction is made larger than the width of each of the plurality of second grooves along the discharge direction; A method for manufacturing a liquid ejection head, comprising:

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