Nozzle plate manufacturing method, liquid jet head and liquid jet device

Abstract

To provide a nozzle plate manufacturing method that can form a nozzle with high accuracy, a liquid jet head with suppressed liquid jet characteristics variation, and a liquid jet device.SOLUTION: A nozzle plate manufacturing method comprises: a first process in which a first nozzle layer 21 formed from silicon, an intermediate layer 22 formed from silicon oxide, and a second nozzle layer 23 formed from silicon are laminated in this order, and a substrate, in which a space part 27 is provided at a part of the intermediate layer 22, is prepared; a second process in which after the first process, the Bosch process is performed for a first area where at least a part of the first nozzle layer 21 overlaps with the space part 27, thereby providing a first nozzle opening 26 communicating with the space part 27; and a third process in which the Bosch process is performed for a second area where at least a part of the second nozzle layer 23 overlaps with the space part 27, thereby providing a second nozzle opening 28 communicating with the space part 27 and having a diameter larger than that of the first nozzle opening 26.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a nozzle plate in which a nozzle for injecting a liquid is formed, a liquid injection head for injecting a liquid, and a liquid injection device including the liquid injection head.

Background Art

[0002] A liquid injection device typified by an inkjet recording device such as an inkjet printer includes a liquid injection head capable of injecting a liquid such as ink stored in a cartridge, a tank, or the like as droplets.

[0003] The liquid injection head includes a nozzle plate provided with nozzles for injecting droplets. Some nozzles include a first nozzle opening provided on the injection surface side, and a second nozzle opening that communicates with the first nozzle opening and has a larger diameter than the first nozzle opening. In order to make the injection characteristics of droplets injected from such nozzles, such as the injection speed and the weight of the droplets, target values, it is necessary to form the length of the first nozzle opening without error. However, when forming the first nozzle opening by ordinary etching, although the length of the first nozzle opening is adjusted by adjusting the etching time, an error occurs due to time control. For this reason, a nozzle plate using an SOI substrate configured by sandwiching an insulating film such as silicon oxide between two silicon substrates has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the first nozzle opening is formed by normal etching using an SOI substrate for the nozzle plate, when the insulating film functions as an etching stop layer, ions are bent due to the charging of the insulating film, and a so-called notching occurs where the portion on the insulating film side of the side wall of the first nozzle opening is etched wide, resulting in a problem that a desired shape cannot be obtained as the first nozzle opening and desired injection characteristics may not be obtained.

Means for Solving the Problems

[0006] An aspect of the present invention for solving the above problems is a method for manufacturing a nozzle plate provided with nozzles mounted on a liquid ejection head, comprising: a first step of preparing a substrate in which a first nozzle layer formed of silicon, an intermediate layer formed of silicon oxide, and a second nozzle layer formed of silicon are laminated in this order, and a space portion is provided in a part of the intermediate layer; a second step of performing a Bosch process on a first region where at least a part of the first nozzle layer overlaps the space portion after the first step to provide a first nozzle opening communicating with the space portion; and a third step of performing a Bosch process on a second region where at least a part of the second nozzle layer overlaps the space portion to provide a second nozzle opening communicating with the space portion and having a diameter larger than that of the first nozzle opening.

[0007] Another aspect of the present invention is a liquid ejection head having a nozzle plate provided with nozzles and a pressure chamber substrate provided with a pressure chamber for applying pressure for ejecting liquid from the nozzles, wherein the nozzle plate has a first nozzle layer formed of silicon, an intermediate layer formed of silicon oxide, and a second nozzle layer formed of silicon, which are laminated in this order, the first nozzle layer is provided with a first nozzle opening, the intermediate layer is provided with a space portion communicating with the first nozzle opening, the second nozzle layer is provided with a second nozzle opening communicating with the space portion and having a diameter larger than that of the first nozzle opening, scallops are formed in the first nozzle opening and the second nozzle opening, respectively, and no scallop is formed in the space portion.

[0008] Furthermore, another aspect of the present invention is a liquid ejection device characterized by including the liquid ejection head described in the above aspect.

Brief Description of the Drawings

[0009]

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Modes for Carrying Out the Invention

[0010] The present invention will be described in detail below based on embodiments. However, the following description shows one aspect of the present invention and can be arbitrarily changed within the scope of the present invention. In each figure, the same reference numerals are used to indicate the same members, and the description is appropriately omitted. Also, in each figure, X, Y, and Z represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are referred to as the X direction, the Y direction, and the Z direction. The direction in which the arrow in each figure points is defined as the positive (+) direction, and the opposite direction of the arrow is defined as the negative (-) direction for explanation. Also, the Z direction indicates the vertical direction, the +Z direction indicates vertically downward, and the -Z direction indicates vertically upward. Furthermore, for the directions of the three spatial axes without limiting the positive and negative directions, they are described as the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0011] (Embodiment 1) FIG. 1 is a diagram showing a schematic configuration of a liquid injection device 1 according to Embodiment 1 of the present invention.

[0012] As shown in FIG. 1, the liquid injection device 1 includes a liquid injection head H, conveys a medium S in the X-axis direction, and reciprocates the liquid injection head H in the Y-axis direction while injecting liquid in the +Z direction from the liquid injection head H toward the medium S to perform printing, which is a so-called serial printer. Note that as the medium S, any material such as recording paper or resin film can be used in addition to cloth. Also, the direction in which the liquid injection head H reciprocates is not limited to the Y-axis direction and may be a direction inclined with respect to both the X-axis direction and the Y-axis direction.

[0013] Such a liquid injection device 1 includes a liquid injection head H, a liquid storage unit 3, a control unit 4 as a control unit, a conveyance mechanism 5 for sending out the medium S, and a moving mechanism 6.

[0014] The liquid injection head H injects the liquid supplied from the liquid storage unit 3 that stores the liquid as droplets in the +Z direction.

[0015] The liquid storage unit 3 stores a plurality of types of liquids with different colors and components ejected from the liquid ejection head H individually. Examples of the liquid storage unit 3 include a cartridge detachable from the liquid ejection apparatus 1, a bag-shaped ink pack formed of a flexible film, and an ink tank capable of replenishing ink. Note that in FIG. 1, one liquid storage unit 3 is illustrated. Incidentally, the liquid storage unit 3 may be a liquid storage unit 3 having divided rooms for storing a plurality of types of liquids individually, or may be a plurality of liquid storage units 3 provided individually according to a plurality of types of liquids. Further, the liquid storage unit 3 may be divided into a main tank and a sub-tank. A configuration may be adopted in which the sub-tank is connected to the liquid ejection head H, and the liquid consumed by ejecting droplets from the liquid ejection head H is replenished from the main tank to the sub-tank.

[0016] The control unit 4 comprehensively controls each element of the liquid ejection apparatus 1, that is, the liquid ejection head H, the conveyance mechanism 5, the movement mechanism 6, and the like.

[0017] The conveyance mechanism 5 conveys the medium S in the X-axis direction and includes conveyance rollers 5a. The conveyance mechanism 5 conveys the medium S in the X-axis direction by rotating the conveyance rollers 5a. The conveyance rollers 5a are rotated by driving of a conveyance motor (not shown). The control unit 4 controls the conveyance of the medium S by controlling the driving of the medium conveyance motor. Note that the conveyance mechanism 5 for conveying the medium S is not limited to one including the conveyance rollers 5a, and for example, may be one that conveys the medium S by a belt or a drum.

[0018] The moving 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 installed along the Y-axis direction. The conveyor belt 8 rotates by the drive of a conveyor motor (not shown). The control unit 4 controls the drive of the conveyor motor to rotate the conveyor belt 8, and reciprocates the liquid ejection head H together with the holder 7 in the Y-axis direction. Note that the holder 7 may be configured to carry the liquid storage unit 3 together with the liquid ejection head H.

[0019] Under the control of the control unit 4, the liquid ejection head H performs an ejection operation of ejecting the liquid supplied from the liquid storage unit 3 as droplets in the +Z direction from each of the plurality of nozzles 25 (see FIG. 2). By performing the ejection operation by this liquid ejection head H in parallel with the conveyance of the medium S by the conveyance mechanism 5 and the reciprocating movement of the liquid ejection head H by the moving mechanism 6, so-called printing in which the liquid is applied to the medium S is performed.

[0020] 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 in a state incorporated in the liquid ejection head H. FIG. 4 is a cross-sectional view of the liquid ejection head H along the line A-A' of FIG. 3. FIG. 5 is an enlarged view of the main part of FIG. 4. Note that each direction of the liquid ejection head H is described based on the direction when mounted on the liquid ejection device 1, that is, the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0021] As shown in the figure, the liquid ejection head H of the present embodiment includes a pressure chamber substrate 10, a communication plate 15, a nozzle plate 20 in which a plurality of nozzles 25 are formed, a protection substrate 30, a case member 40, a piezoelectric actuator 300, and a wiring member 110.

[0022] The pressure chamber substrate 10 is made of, for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, etc. A plurality of pressure chambers 12 are arranged side by side along the X-axis direction. The plurality of 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 pressure chambers 12 adjacent to each other in the X-axis direction are partitioned by a partition wall (not shown). Also, in the present embodiment, two rows of pressure chamber columns in which the pressure chambers 12 are arranged side by side along the X-axis direction are provided in the Y-axis direction. Of course, the arrangement of the pressure chambers 12 is not particularly limited to this. For example, the plurality of pressure chambers 12 may be arranged in a staggered pattern along the X-axis direction. Here, the pressure chambers 12 being arranged in a staggered pattern along the X-axis direction means arranging the pressure chambers 12 arranged side by side in the X-axis direction alternately shifted in the Y-axis direction. That is, two rows of pressure chamber columns 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 rows of pressure chamber columns are arranged shifted from each other in the X-axis direction by half of the pitch of the pressure chambers 12, that is, by a so-called half pitch.

[0023] On the surface of the pressure chamber substrate 10 facing the +Z direction, a communication plate 15 and a nozzle plate 20 are sequentially stacked. On the surface of the pressure chamber substrate 10 facing the -Z direction, a diaphragm 50 and a piezoelectric actuator 300 are sequentially laminated.

[0024] The communication plate 15 is composed of a plate-like member joined to the surface of the pressure chamber substrate 10 facing the +Z direction. The communication plate 15 is provided with a nozzle communication path 16 that communicates the pressure chamber 12 and the nozzle 25. Further, the communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 that constitute a part of a manifold 100 that serves as a common liquid chamber in which a plurality of pressure chambers 12 communicate in common. The first manifold portion 17 is provided penetrating the communication plate 15 in the Z-axis direction. Further, the second manifold portion 18 is provided opening to the surface facing the +Z direction without penetrating the communication plate 15 in the Z-axis direction. Furthermore, a supply communication path 19 that communicates with one end portion of the pressure chamber 12 in the Y-axis direction is provided independently for each of the pressure chambers 12 in the communication plate 15. The supply communication path 19 communicates the second manifold portion 18 and the pressure chamber 12 to supply the ink in the manifold 100 to the pressure chamber 12. As such a communication plate 15, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate such as a stainless steel substrate, etc. can be used. It is preferable to use, for the communication plate 15, a material having a linear expansion coefficient equivalent to that of the substrate joined to the communication plate 15, that is, 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 substrate joined to the communication plate 15 for the communication plate 15, it is possible to suppress the occurrence of peeling, cracks, etc. due to warping caused by the difference in the linear expansion coefficients of the two.

[0025] The nozzle plate 20 is joined to the surface of the communication plate 15 opposite to the pressure chamber substrate 10, that is, the surface facing the +Z direction. A plurality of nozzles 25 that communicate with each pressure chamber 12 via the nozzle communication path 16 are formed in the nozzle plate 20. In the present embodiment, the plurality of nozzles 25 are arranged side by side in a line along the X-axis direction. Further, in the present embodiment, two rows of nozzle rows in which the nozzles 25 are arranged side by side along the X-axis direction are provided separated from each other in the Y-axis direction. Such a nozzle plate 20 is constituted by an SOI substrate.

[0026] As shown in FIG. 5, the nozzle plate 20 includes a first nozzle layer 21 formed of silicon, an intermediate layer 22 formed of silicon oxide, for example, silicon dioxide (SiO2), and a second nozzle layer 23 formed of silicon. The first nozzle layer 21, the intermediate layer 22, and the second nozzle layer 23 are laminated in the -Z direction in this order.

[0027] The thickness of the first nozzle layer 21 along the Z-axis direction is thinner than the thickness of the second nozzle layer 23, and the thickness of the intermediate layer 22 along the Z-axis direction is thinner than the thickness of the first nozzle layer 21. That is, the thickness along the Z-axis direction is thickest in the order of the intermediate layer 22, the first nozzle layer 21, and the second nozzle layer 23.

[0028] The nozzle 25 is for ejecting ink droplets in the +Z direction, and includes a first nozzle opening 26 formed in the first nozzle layer 21, a space portion 27 formed in the intermediate layer 22, and a second nozzle opening 28 formed in the second nozzle layer 23. These first nozzle opening 26, space portion 27, and second nozzle opening 28 are arranged side by side in the -Z direction in this order.

[0029] Scallops 26a and 28a are respectively formed on the side walls of the first nozzle opening 26 and the second nozzle opening 28. Here, the scallops 26a and 28a are the shapes of waveforms such as those recognized on the surface of a shell on the side walls of a through hole or a recess formed in a silicon substrate by a Bosch process, that is, the shapes in which a plurality of recesses are formed. The Bosch process is a method of forming a substantially vertical through hole by alternately repeating etching and coating.

[0030] Also, no scallop is formed in the space portion 27. That is, the side wall surface of the space portion 27 is a flat surface along the Z-axis direction.

[0031] The inner diameter d2 of such a second nozzle opening 28 is larger than the inner diameter d1 of the first nozzle opening 26. That is, the inner diameter d1 of the first nozzle opening 26 and the inner diameter d2 of the second nozzle opening 28 satisfy the relationship d1 < d2. Here, the inner diameter of the first nozzle opening 26 refers to the smallest inner diameter of the first nozzle opening 26. For example, when the inner diameter of the first nozzle opening 26 is different between the intermediate layer 22 side and the side opposite to the intermediate layer 22, that is, when the first nozzle opening 26 gradually narrows from the intermediate layer 22 side toward the side opposite to the intermediate layer 22, the inner diameter of the first nozzle opening 26 refers to the inner diameter of the portion on the side opposite to the intermediate layer 22. Further, although scallops are formed on the side wall of the first nozzle opening 26, the inner diameter of the first nozzle opening 26 refers to the inner diameter of the smallest portion due to the scallops. Note that the inner diameter of the first nozzle opening 26 may be the largest inner diameter, or may be an average value of inner diameters measured at several positions in the depth direction, etc. The same applies to the inner diameter d2 of the second nozzle opening 28 as to the inner diameter d1 of the first nozzle opening 26.

[0032] The inner diameter d3 of the space portion 27 is larger than the inner diameter d1 of the first nozzle opening 26 and smaller than the inner diameter d2 of the second nozzle opening 28. That is, the inner diameter d1 of the first nozzle opening 26, the inner diameter d2 of the second nozzle opening 28, and the inner diameter d3 of the space portion 27 satisfy the relationship d1 < d3 < d2. In this way, in the nozzle 25, the inner diameter gradually decreases in the direction of ink flow in the order of the second nozzle opening 28, the space portion 27, and the first nozzle opening 26, so that it is possible to suppress the formation of places where bubbles and ink stay in the nozzle 25. For this reason, it is possible to suppress the occurrence of landing position deviation of ink droplets on the medium S due to the bending of the ink droplet ejection direction and ejection failure such as non-ejection of ink droplets caused by bubbles staying in the nozzle 25.

[0033] Further, the second nozzle layer 23 has a groove 29 that opens to the wall surface of the second nozzle opening 28 at the interface with the intermediate layer 22. This groove 29 is formed by notching that occurs when the second nozzle opening 28 is formed in the second nozzle layer 23 by etching. Here, notching refers to the situation where, when forming a through-hole by etching from one side of a silicon substrate, the insulating film provided on the other side of the silicon substrate functions as an etching stop layer, causing the insulating film to become charged. The ions used for etching are bent, and the portion of the side wall of the through-hole on the insulating film side is etched wide to form a groove. In this embodiment, the second nozzle layer 23 is assumed to have the groove 29. However, when forming the second nozzle opening 28, notching does not necessarily occur, and the groove 29 is not necessarily formed. This is because, when forming the second nozzle opening 28 in the second nozzle layer 23 by etching, there are portions with a large etching rate and portions with a small etching rate in the plane of the second nozzle layer 23. To avoid forming unpenetrated portions in the second nozzle opening 28, a certain amount of over-etching is performed. At this time, the portions with a large etching rate penetrate at an early timing, so notching is likely to occur. In the portions with a small etching rate, notching does not occur or is less likely to occur. That is, there are cases where the groove 29 is formed continuously in the circumferential direction of the second nozzle opening 28, cases where the groove 29 is formed intermittently in the circumferential direction, and cases where the groove 29 is not formed at all.

[0034] Moreover, no groove that opens to the wall surface of the first nozzle opening 26 is formed at the interface between the first nozzle layer 21 and the intermediate layer 22. This is because, as will be described in detail later, when the first nozzle opening 26 is formed in the first nozzle layer 21 by etching, since the space portion 27 exists, notching does not occur.

[0035] Thus, since no groove is formed by notching at the boundary between the intermediate layer 22 and the first nozzle opening 26, the first nozzle opening 26 can have substantially the same opening area over the Z-axis direction. Therefore, the shape of the first nozzle opening 26 can be stabilized, and variations in the ejection characteristics of the ink droplets ejected from the nozzle 25 can be suppressed.

[0036] Further, by forming the groove 29 at the boundary between the intermediate layer 22 and the second nozzle opening 28, even if excess adhesive flows into the second nozzle opening 28 when the nozzle plate 20 and the communication plate 15 are adhered with an adhesive, the adhesive can be drained into the groove 29, suppressing the adhesive from flowing into the first nozzle opening 26 side. That is, the groove 29 functions as an adhesive escape groove. By flowing the excess adhesive into the groove 29 in this way, it is possible to suppress the change in the shape of the first nozzle opening 26 due to the adhesive flowing into the first nozzle opening 26, and to suppress variations in the ejection characteristics of the ink droplets caused by the adhesive. Note that the dominant parameters determining the ejection characteristics of the ink droplets are the dimension d1 of the opening 26 of the first nozzle and the depth in the Z-axis direction. Therefore, even if the groove 29 is formed at the boundary between the intermediate layer 22 and the second nozzle opening 28, if no groove is formed by notching in the first nozzle opening 26, it will not have a significant impact on the ejection characteristics of the ink droplets.

[0037] In addition, protective films 21a and 23a such as silicon oxide are formed on the exposed surfaces of the first nozzle layer 21 and the second nozzle layer 23. That is, the protective film 21a is formed on the surface of the first nozzle layer 21 facing the +Z direction, on the side wall surface of the first nozzle opening 26, and on the surface exposed by the space portion 27 of the first nozzle layer 21. Further, the protective film 23a is formed on the surface of the second nozzle layer 23 facing the -Z direction, on the side wall surface of the second nozzle opening 28, and on the inner surface of the groove 29. That is, the first nozzle opening 26 and the second nozzle opening 28 are actually formed inside the protective films 21a and 23a. Such protective films 21a and 23a are not particularly limited, and examples include silicon oxide formed by thermally oxidizing silicon. Of course, the protective films 21a and 23a may be formed by a method other than thermal oxidation, and the material thereof is not limited to silicon oxide. Further, when the protective films 21a and 23a are formed by a method other than thermal oxidation, a protective film may also be formed on the surface of the intermediate layer 22.

[0038] Also, the shape of the nozzle 25 is not particularly limited thereto. Here, modified examples of the nozzle 25 are shown in FIGS. 6 to 8. Note that FIGS. 6 to 8 are cross-sectional views showing modified examples of the nozzle 25 according to Embodiment 1 of the present invention.

[0039] As shown in FIG. 6, the inner diameter d4 of the space portion 27 is larger than the inner diameter d2 of the second nozzle opening 28. That is, the inner diameter d4 of the space portion 27 and the inner diameter d2 of the second nozzle opening 28 satisfy the relationship d4>d2. In this way, by making the inner diameter d4 of the space portion 27 larger than the inner diameter d2 of the second nozzle opening 28, the side wall of the space portion 27 is formed outside the side wall of the second nozzle opening 28. That is, a recess is formed by the space portion 27 between the side wall of the second nozzle opening 28 and the side wall of the first nozzle opening 26. By forming the recess by the space portion 27 in this way, foreign matter contained in the ink flowing into the second nozzle opening 28 is trapped in the space portion 27, reducing the foreign matter from going toward the first nozzle opening 26, and suppressing clogging of the first nozzle opening 26 due to foreign matter. Further, by providing the space portion 27 serving as the recess, even if excess adhesive flows into the second nozzle opening 28 when the nozzle plate 20 and the communication plate 15 are adhered with an adhesive, the adhesive can be allowed to escape into the space portion 27, suppressing the adhesive from flowing into the first nozzle opening 26 side. That is, the space portion 27 also functions as an adhesive escape groove. By flowing excess adhesive into the space portion 27 in this way, it is possible to suppress the shape of the first nozzle opening 26 from changing due to the adhesive flowing into the first nozzle opening 26, and to suppress variations in the ejection characteristics of ink droplets due to the adhesive.

[0040] Also, as shown in FIG. 7, the space portion 27 includes a first portion 27a on the side of the second nozzle opening 28 and a second portion 27b having an inner diameter smaller than that of the first portion 27a on the side of the first nozzle opening 26. The inner diameter d5 of the first portion 27a is larger than the inner diameter d2 of the second nozzle opening 28, and the inner diameter d6 of the second portion 27b is smaller than the inner diameter d2 of the second nozzle opening 28. That is, the inner diameter d5 of the first portion 27a, the inner diameter d6 of the second portion 27b, and the inner diameter d2 of the second nozzle opening 28 satisfy the relationship of d5>d2>d6. Further, the inner diameter d5 of the first portion 27a and the inner diameter d6 of the second portion 27b are each larger than the inner diameter d1 of the first nozzle opening 26. That is, the inner diameter d5 of the first portion 27a, the inner diameter d6 of the second portion 27b, the inner diameter d1 of the first nozzle opening 26, and the inner diameter d2 of the second nozzle opening 28 satisfy the relationship of d5>d2>d6>d1. Even in the configuration where the space portion 27 has the first portion 27a and the second portion 27b, a recess is formed between the side wall of the second nozzle opening 28 and the side wall of the second portion 27b by the first portion 27a in the same manner as in FIG. 6 described above. Therefore, foreign matter contained in the ink can be captured in the recess formed by the first portion 27a in the side walls of the first nozzle opening 26 and the second nozzle opening 28, and clogging of the first nozzle opening 26 due to foreign matter can be suppressed. Further, an excess adhesive can be poured into the recess formed by the first portion 27a, and deformation of the shape of the first nozzle opening 26 due to the adhesive can be suppressed. Further, since the inner diameters can be gradually reduced in the order of the second nozzle opening 28, the second portion 27b, and the first nozzle opening 26, it is difficult to inhibit the flow of ink.

[0041] Also, as shown in FIG. 8, the space portion 27 has an inner diameter d7 that is smaller than the inner diameter d2 of the second nozzle opening 28 and smaller than the inner diameter d1 of the first nozzle opening 26. That is, the inner diameter d7 of the space portion 27, the inner diameter d1 of the first nozzle opening 26, and the inner diameter d2 of the second nozzle opening 28 satisfy the relationship of d2>d1>d7. In this way, by making the inner diameter d7 of the space portion 27 smaller than the inner diameter d1 of the first nozzle opening 26, even if foreign matter enters from the first nozzle opening 26, the foreign matter can be suppressed from moving to the second nozzle opening 28 side by the intermediate layer 22 protruding inward from the first nozzle opening 26.

[0042] In this embodiment, the diaphragm 50 includes an elastic film 51 made of silicon oxide provided on the side of the pressure chamber substrate 10, and an insulator film 52 made of zirconium oxide provided on the surface of the elastic film 51 facing the -Z direction. Note that the diaphragm 50 may be composed of only the elastic film 51, may be composed of only the insulator film 52, or may have a configuration including other films in addition to the elastic film 51 and the insulator film 52.

[0043] The piezoelectric actuator 300 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80 sequentially stacked in the -Z direction on the diaphragm 50. 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. Further, when a voltage is applied between the first electrode 60 and the second electrode 80, a portion where piezoelectric strain occurs in the piezoelectric layer 70 is referred to as an active portion 310. In contrast, a portion where no piezoelectric strain occurs in the piezoelectric layer 70 is referred to as an inactive portion. That is, the active portion 310 refers to a portion where the piezoelectric layer 70 is 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. That is, a plurality of active portions 310 are formed in the piezoelectric actuator 300. These plurality of active portions 310 serve as drive elements that cause a pressure change in the ink in the pressure chamber 12. Generally, one of the electrodes of the active portion 310 is configured as an individual electrode independent for each active portion 310, and the other electrode is configured as a common electrode 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. Of course, the first electrode 60 may constitute the common electrode, and the second electrode 80 may constitute the individual electrode.

[0044] As shown in FIG. 3, the first electrode 60 is divided for each pressure chamber 12 to constitute individual electrodes that are independent for each active portion 310. As shown in FIGS. 3 and 4, the piezoelectric layer 70 has a predetermined width in the Y-axis direction and is continuously provided across the X-axis direction. Further, as shown in FIG. 3, a plurality of recesses 71 are formed in the piezoelectric layer 70 at positions that do not overlap with the first electrode 60, but the recesses 71 may not be provided. Such a piezoelectric layer 70 is configured using, for example, a piezoelectric material made of a complex oxide having a perovskite structure represented by the general formula ABO3. As shown in FIGS. 3 and 4, the second electrode 80 is continuously provided on the -Z direction side, which is the side opposite to the first electrode 60 of the piezoelectric layer 70, and constitutes a common electrode common to the plurality of active portions 310. The second electrode 80 is continuously provided across the X-axis direction so that the Y-axis direction has a predetermined width.

[0045] In addition, individual lead electrodes 91, which are lead-out wirings, are drawn out from the first electrode 60. A common lead electrode 92, which is a lead-out wiring, is drawn out from the second electrode 80. A wiring member 110 made of a flexible substrate having flexibility is connected to the ends of the individual lead electrodes 91 and the common lead electrode 92 on the side opposite to the ends connected to the piezoelectric actuator 300. The wiring member 110 is mounted with a drive signal selection circuit 111 having a plurality of switching elements for selecting whether to supply a drive signal COM for driving each of the active portions 310 to each active portion 310. That is, the wiring member 110 in the present embodiment is a COF (Chip On Film). Note that the drive signal selection circuit 111 may not be provided in the wiring member 110. That is, the wiring member 110 may be an FFC (Flexible Flat Cable), an FPC (Flexible Printed Circuits), or the like.

[0046] On the surface of the pressure chamber substrate 10 facing the -Z direction, as shown in FIGS. 2 and 4, a protective substrate 30 having substantially the same size as the pressure chamber substrate 10 is joined. The protective substrate 30 has a housing portion 31 which is a space for protecting the piezoelectric actuator 300. The housing portion 31 is provided independently for each row of piezoelectric actuators 300 arranged side by side in the X-axis direction, and two of them are formed side by side in the Y-axis direction. Further, the protective substrate 30 is provided with a through hole 32 penetrating in the Z-axis direction between the two housing portions 31 arranged side by side in the Y-axis direction. The ends of the individual lead electrodes 91 and the common lead electrode 92 drawn from the electrodes of the piezoelectric actuator 300 extend so as to be exposed in this through hole 32, and the individual lead electrodes 91 and the common lead electrode 92 and the wiring member 110 are electrically connected in the through hole 32. As such a protective substrate 30, for example, it is made of a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates similar to the pressure chamber substrate 10.

[0047] Further, on the protective substrate 30, a case member 40 that defines a manifold 100 communicating with a plurality of pressure chambers 12 together with the pressure chamber substrate 10 is fixed. The case member 40 has substantially the same shape as the above-described communication plate 15 in plan view, is joined to the protective substrate 30, and is also joined to the above-described communication plate 15. Such a case member 40 has a recess 41 on the protective substrate 30 side with a depth in which the pressure chamber substrate 10 and the protective substrate 30 are accommodated. Further, the case member 40 is provided with a third manifold portion 42 communicating with the first manifold portion 17 of the communication plate 15. The first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15 and the third manifold portion 42 provided on the case member 40 constitute the manifold 100 of the present embodiment. Two manifolds 100 are provided for each row of the pressure chambers 12, that is, a total of two. Each manifold 100 is continuously provided across the X-axis direction in which the pressure chambers 12 are arranged side by side, and the supply communication paths 19 that communicate each pressure chamber 12 with the manifold 100 are arranged side by side in the X-axis direction. Further, the case member 40 is provided with an inlet 44 that communicates with the manifold 100 to supply ink to each manifold 100. Further, the case member 40 is provided with a connection port 43 through which a wiring member 110 is inserted and that communicates with the through hole 32 of the protective substrate 30, and the wiring member 110 is led out to the surface side facing the -Z direction of the liquid ejection head H through the connection port 43. As the case member 40, a metal material, a resin material, or the like can be used.

[0048] Further, a compliance substrate 45 is provided on the +Z-direction side surface where the first manifold portion 17 and the second manifold portion 18 of the communication plate 15 open. This compliance substrate 45 seals the openings on the +Z-direction side of the first manifold portion 17 and the second manifold portion 18. In this embodiment, such a 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. Since the region of the fixed substrate 47 facing the manifold 100 is an opening 48 that is completely removed in the thickness direction, one surface of the manifold 100 is a compliance portion 49 that is a flexible portion sealed only by the flexible sealing film 46.

[0049] In such a liquid ejection head H, ink is taken in from the ink introduction port 44, and the inside of the flow path from the manifold 100 to the nozzle 25 is filled with ink. Then, according to the signal from the drive signal selection circuit 111, a voltage is applied to each active portion 310 corresponding to the pressure chamber 12, thereby deflecting and deforming the diaphragm 50 together with the piezoelectric actuator 300. As a result, the pressure of the ink in the pressure chamber 12 increases, and ink droplets are ejected from a predetermined nozzle 25.

[0050] A method for manufacturing the nozzle plate 20 of the liquid ejection head H according to this embodiment will be described with reference to FIGS. 9 to 15. FIGS. 9 to 15 are cross-sectional views for explaining the method for manufacturing the nozzle plate.

[0051] First, as shown in FIG. 9, a first step is performed of preparing a substrate 120 in which a first nozzle layer 21 formed of silicon, an intermediate layer 22 formed of silicon oxide, and a second nozzle layer 23 formed of silicon are laminated in this order toward the -Z direction, and a space portion 27 is formed in a part of the intermediate layer 22.

[0052] The substrate 120 is made of a so-called SOI substrate. That is, in the first step, first, the surface of the second nozzle layer 23 is oxidized to form an oxide film over the surface of the second nozzle layer 23. Next, the oxide film is patterned into a predetermined shape by a lithography method to form an intermediate layer 22 having a space portion 27. Then, the substrate 120 is formed by bonding the second nozzle layer 23 on which the intermediate layer 22 is formed and the first nozzle layer 21. Note that the inner diameter d3 of the space portion 27 of the intermediate layer 22 is formed to be smaller than the inner diameter d2 of the second nozzle opening 28 in advance as shown in FIG. 5. In addition, since the intermediate layer 22 is etched in a later step, it is preferable to form the inner diameter in advance to be smaller than the inner diameter d3. Further, as shown in FIG. 8, the space portion 27 may be formed with an inner diameter d7 smaller than the inner diameter d1 of the first nozzle opening 26. Note that if an SOI substrate in which the space portion 27 is formed in a part of the intermediate layer 22 can be prepared, the first step does not have to be the manufacturing method as described above. For example, the surface of the first nozzle layer 21 instead of the second nozzle layer 23 may be oxidized. Alternatively, an SOI substrate in which the space portion 27 is formed in a part of the intermediate layer 22 may be procured from the outside.

[0053] Next, as shown in FIG. 10, a second step is performed in which a Bosch process is carried out on a first region 121 (see FIG. 9) where at least a part of the first nozzle layer 21 overlaps with the space portion 27 to provide a first nozzle opening 26 that communicates with the space portion 27. In the second step, in the present embodiment, the Bosch process is carried out from the surface on the opposite side of the intermediate layer 22 of the first nozzle layer 21, that is, from the surface facing the +Z direction of the first nozzle layer 21. In the Bosch process for forming the first nozzle opening 26, since the space portion 27 is formed in the intermediate layer 22, notching due to charging of the intermediate layer 22 does not occur. This is because when the first nozzle layer 21 is penetrated, the surface facing the +Z direction of the second nozzle layer 23 is etched, so ions do not stay between the intermediate layer 22 of the first nozzle opening 26. That is, no groove due to notching is formed at the boundary between the first nozzle opening 26 and the intermediate layer 22. Incidentally, if the space portion 27 is not formed in the intermediate layer 22, notching may occur when the first nozzle opening 26 is formed in the first nozzle layer 21 by the Bosch process, and a groove may be formed at the boundary between the first nozzle opening 26 and the intermediate layer 22. In the present embodiment, by providing the space portion 27 in the intermediate layer 22 in advance, the occurrence of notching can be suppressed when the first nozzle opening 26 is formed, and the formation of a groove at the boundary between the first nozzle opening 26 and the intermediate layer 22 can be suppressed. Therefore, the first nozzle opening 26 can be formed in a desired shape, and the adverse effect on the discharge characteristics due to the shape defect of the first nozzle opening 26 can be suppressed.

[0054] Next, as shown in FIG. 11, after the second step, a fourth step is performed in which an oxide film 122 is formed so as to cover at least the first nozzle opening 26 of the first nozzle layer 21. In the fourth step, in the present embodiment, by oxidizing the entire substrate 120, an oxide film 122 is formed on the surface not covered by the intermediate layer 22 of the first nozzle layer 21, that is, on the exposed surface including the side wall surface of the first nozzle opening 26 of the first nozzle layer 21, and an oxide film 123 is formed on the surface not covered by the intermediate layer 22 of the second nozzle layer 23.

[0055] Next, as shown in FIG. 12, after the fourth step, a fifth step of thinning the second nozzle layer 23 of the substrate 120 is performed. The fifth step is performed by grinding and polishing the second nozzle layer 23 from the side of the surface facing the opposite side of the intermediate layer 22 of the second nozzle layer 23, that is, the surface facing the -Z direction, by chemical mechanical polishing (CMP) or the like. Note that the thinning of the second nozzle layer 23 in the fifth step is not limited to grinding and polishing, and for example, the second nozzle layer 23 may be thinned by etching.

[0056] Next, as shown in FIG. 13, a third step of performing a Bosch process on a second region 124 (see FIG. 12) where at least a part of the second nozzle layer 23 overlaps with the space portion 27 to provide a second nozzle opening 28 communicating with the space portion 27 is performed. In the third step, in the present embodiment, the Bosch process is performed from the surface on the opposite side of the intermediate layer 22 of the second nozzle layer 23, that is, the surface of the second nozzle layer 23 facing the -Z direction. In the Bosch process for forming the second nozzle opening 28, since the oxide film 123 functions as an etching stop layer, notching occurs due to the charging of the oxide film 123, and a groove 29 is formed at the boundary between the second nozzle opening 28 and the intermediate layer 22. Even if such a groove 29 is formed at the boundary between the second nozzle opening 28 and the intermediate layer 22, if no groove is formed in the first nozzle opening 26, it does not significantly affect the ink droplet ejection characteristics. Further, by performing the third step after the fourth step, since the first nozzle layer 21 is covered by the oxide film 122, it is possible to suppress the simultaneous etching of the first nozzle layer 21 when forming the second nozzle layer 23 in the third step.

[0057] Next, as shown in FIG. 14, the oxide films 122 and 123 on the substrate 120 are removed. In the present embodiment, the oxide film 122 of the first nozzle layer 21 and the oxide film 123 of the second nozzle layer 23 are removed by etching with hydrofluoric acid or the like. As a result, the oxide film 123 that separated the first nozzle opening 26 and the second nozzle opening 28 is removed, and the first nozzle opening 26 and the second nozzle opening 28 communicate with each other in the space portion 27. Note that in this step, when the oxide films 122 and 123 are removed by etching, a part of the intermediate layer 22 formed of silicon oxide is also removed. Therefore, for example, by adjusting the etching time, as shown in FIG. 5, the inner diameter d3 of the space portion 27 can be formed to be smaller than the inner diameter d2 of the second nozzle opening 28, or as shown in FIG. 6, the inner diameter d4 of the space portion 27 can be formed to be larger than the inner diameter d2 of the second nozzle opening 28. In addition, by stopping the etching halfway when the state shown in FIG. 6 is obtained when forming the space portion 27, a space portion 27 having a first portion 27a and a second portion 27b can be formed as shown in FIG. 7. Incidentally, in the present embodiment, in the first step, the inner diameter d3 of the space portion 27 was formed to be larger than the inner diameter d1 of the first nozzle opening 26 and smaller than the inner diameter d2 of the second nozzle opening 28, but it is not particularly limited thereto. For example, in the first step, as shown in FIG. 8, if the inner diameter d7 of the space portion 27 is formed to be smaller than the inner diameter d1 of the first nozzle opening 26, then in the step shown in FIG. 14, by adjusting the etching time, the space portion 27 shown in any of FIGS. 5 to 8 can be formed. The manufacturing method of the present embodiment illustrates a figure in which the space portion 27 shown in FIG. 5 is formed.

[0058] Next, as shown in FIG. 15, a protective film 21a is formed on the first nozzle layer 21 and a protective film 23a is formed on the second nozzle layer 23. In the present embodiment, by oxidizing the entire substrate 120, the protective films 21a and 23a are simultaneously formed on the first nozzle layer 21 and the second nozzle layer 23. As a result, the nozzle plate 20 of the present embodiment is manufactured.

[0059] As described above, in the manufacturing method of the nozzle plate 20 of the present embodiment, no groove is formed by notching at the boundary of the first nozzle opening 26 on the intermediate layer 22 side. Therefore, the shape of the first nozzle opening 26 can be stably formed. Further, since the length of the first nozzle opening 26 in the Z-axis direction can be controlled by the thickness of the first nozzle layer 21, the length of the first nozzle opening 26 can be formed with high precision as compared with the case of adjusting by the etching time. Therefore, it is possible to suppress variations in the ink ejection characteristics due to unstable shape of the nozzle 25 and suppress variations in the print quality.

[0060] (Embodiment 2) FIG. 16 is a cross-sectional view of a main part of the nozzle plate 20 according to Embodiment 2 of the present invention. Note that the same members as those in Embodiment 1 described above are denoted by the same reference numerals and redundant descriptions are omitted.

[0061] The nozzle plate 20 of the present embodiment is made of an SOI substrate including a first nozzle layer 21, an intermediate layer 22, and a second nozzle layer 23, similarly to Embodiment 1 described above.

[0062] The nozzle 25 includes a first nozzle opening 26, a space portion 27, and a second nozzle opening 28. The inner diameter d8 of the space portion 27 is substantially the same as the inner diameter d1 of the first nozzle opening 26 or slightly larger than the inner diameter d1 of the first nozzle opening 26 by the thickness of the protective film 21a.

[0063] Further, the inner diameter d8 of the space portion 27 is smaller than the inner diameter d2 of the second nozzle opening 28.

[0064] Scallops 26a and 28a are formed on the side walls of the first nozzle opening 26 and the second nozzle opening 28, respectively. Further, no scallop is formed on the side wall of the space portion 27, and it is flat along the Z-axis direction.

[0065] Further, no groove is formed by notching at the boundary of the second nozzle opening 28 with the intermediate layer 22. No groove is formed by notching at the boundary of the first nozzle opening 26 with the intermediate layer 22.

[0066] In such a nozzle 25, since grooves formed by notching are not formed in the first nozzle opening 26 and the second nozzle opening 28, the shapes of the first nozzle opening 26 and the second nozzle opening 28 can be formed with high precision into desired shapes.

[0067] A method for manufacturing such a nozzle plate 20 will be described with reference to FIGS. 17 to 20. FIGS. 17 to 20 are cross-sectional views for explaining a method for manufacturing the nozzle plate 20 according to Embodiment 2 of the present invention.

[0068] First, as shown in FIG. 17, a first nozzle layer 21 formed of silicon, an intermediate layer 22 formed of silicon oxide, and a second nozzle layer 23 formed of silicon are laminated in this order toward the -Z direction, and a first step of preparing a substrate 120 in which a space portion 27 is formed in a part of the intermediate layer 22 is performed.

[0069] Next, as shown in FIG. 18, after the first step, a fifth step of thinning the second nozzle layer 23 of the substrate 120 is performed.

[0070] Next, as shown in FIG. 19, after the fifth step, a third step of performing a Bosch process on a second region 124 (see FIG. 18) where at least a part of the second nozzle layer 23 overlaps with the space portion 27 to provide a second nozzle opening 28 communicating with the space portion 27 is performed. In the third step, in the present embodiment, the Bosch process is performed from the surface side facing the -Z direction of the second nozzle layer 23, that is, the surface of the second nozzle layer 23 opposite to the intermediate layer 22. In the Bosch process for forming the second nozzle opening 28, since the space portion 27 is formed in the intermediate layer 22, notching hardly occurs, and a groove is not formed at the boundary between the second nozzle opening 28 and the intermediate layer 22.

[0071] Next, as shown in FIG. 20, after the third step, a Bosch process is performed from the second nozzle layer 23 side on a first region 121 (see FIG. 19) where at least a part of the first nozzle layer 21 overlaps with the space portion 27, and a second step of providing a first nozzle opening 26 communicating with the space portion 27 is performed. In the second step, the surface of the first nozzle layer 21 on the second nozzle layer 23 side, that is, the surface facing the -Z direction, is covered by the intermediate layer 22. That is, in the second step, the first nozzle opening 26 is formed by performing a Bosch process on the first nozzle layer 21 using the intermediate layer 22 as a mask. That is, the above-described fifth step is performed after the first step and before the third step.

[0072] Thus, since the first nozzle opening 26 is formed by performing a Bosch process on the first nozzle layer 21 from the second nozzle layer 23 side, notching does not occur, and grooves due to notching are not formed on the side walls of the first nozzle opening 26. In addition, since the length of the first nozzle opening 26 in the Z-axis direction is defined by the thickness of the first nozzle layer 21, it is possible to suppress variations in the length of the first nozzle layer 21 in the Z-axis direction.

[0073] Thereafter, in the same manner as in FIG. 15 of the above-described Embodiment 1, a protective film 21a is formed on the first nozzle layer 21, and a protective film 23a is formed on the second nozzle layer 23. Thereby, the nozzle plate 20 is manufactured.

[0074] As described above, in the method for manufacturing the nozzle plate 20 of the present embodiment, a groove formed by notching is not formed at the boundary on the intermediate layer 22 side of the first nozzle opening 26. Therefore, the shape of the first nozzle opening 26 can be stably formed. Further, since the length of the first nozzle opening 26 in the Z-axis direction can be controlled by the thickness of the first nozzle layer 21, the length of the first nozzle opening 26 can be formed with high precision as compared with the case where it is adjusted by the etching time. Therefore, it is possible to suppress variations in the ink ejection characteristics due to unstable nozzle 25 shapes and suppress variations in print quality. Also, in the method for manufacturing the nozzle plate 20 of the present embodiment, a groove formed by notching is not formed in the second nozzle opening 28 either. This also makes it possible to suppress variations in the shape of the nozzle 25.

[0075] (Other embodiments) As described above, each embodiment of the present invention has been described, but the basic configuration of the present invention is not limited to those described above.

[0076] In each of the above-described embodiments, a thin-film piezoelectric actuator has been described as a driving element that causes a pressure change in the pressure chamber 12, but it is not particularly limited thereto. For example, a thick-film piezoelectric actuator formed by a method such as attaching a green sheet, or a longitudinal vibration type piezoelectric actuator in which a piezoelectric material and an electrode forming material are alternately laminated and expanded and contracted in the axial direction can be used. Further, as a driving element, a heat generating element is arranged in the pressure generating chamber, and droplets are ejected from the nozzle by bubbles generated by the heat generation of the heat generating element, or static electricity is generated between the diaphragm and the electrode, and the diaphragm is deformed by the electrostatic force to eject droplets from the nozzle. A so-called electrostatic actuator or the like can be used.

[0077] Furthermore, the present invention is directed to liquid injection devices in general that widely include a liquid injection head. Examples of the liquid injection head include recording heads such as various inkjet recording heads used in image recording devices such as printers, and colorant injection heads used in the manufacture of color filters such as liquid crystal displays. In addition, examples of the liquid injection head include electrode material injection heads used for forming electrodes in organic EL displays, FED (field emission displays), etc., and bio-organic matter injection heads used in the manufacture of biochips, etc. The present invention can also be applied to liquid injection devices equipped with these liquid injection heads.

[0078] Also, although an inkjet recording device has been described as an example of the liquid injection device, it can also be used in liquid injection devices using the other liquid injection heads described above.

[0079] In the above-described embodiments, an inkjet recording head that injects ink has been described as an example of the liquid injection head, and an inkjet recording device has been described as an example of the liquid injection device. However, the present invention is directed to liquid injection heads and liquid injection devices in general, and can of course be applied to liquid injection heads and liquid injection devices that inject liquids other than ink. Examples of other liquid injection heads include various recording heads used in image recording devices such as printers, colorant injection heads used in the manufacture of color filters such as liquid crystal displays, electrode material injection heads used for forming electrodes in organic EL displays, FED (field emission displays), etc., and bio-organic matter injection heads used in the manufacture of biochips, etc. The present invention can also be applied to liquid injection devices equipped with such liquid injection heads.

[0080] (Supplementary Note) From the embodiments exemplified above, for example, the following configurations can be understood.

[0081] The manufacturing method of a nozzle plate according to Mode 1, which is a suitable mode, is a manufacturing method of a nozzle plate provided with nozzles to be mounted on a liquid ejection head, including: a first nozzle layer formed of silicon, an intermediate layer formed of silicon oxide, and a second nozzle layer formed of silicon, which are laminated in this order; a first step of preparing a substrate in which a space portion is provided in a part of the intermediate layer; a second step of performing a Bosch process on a first region where at least a part of the first nozzle layer overlaps with the space portion after the first step, and providing a first nozzle opening communicating with the space portion; and a third step of performing a Bosch process on a second region where at least a part of the second nozzle layer overlaps with the space portion, and providing a second nozzle opening communicating with the space portion and having a diameter larger than that of the first nozzle opening.

[0082] According to this, when forming the first nozzle opening in the second step, since the space portion is formed in the intermediate layer in advance, notching hardly occurs when forming the first nozzle opening, and a groove is not formed at the boundary between the first nozzle opening and the intermediate layer. Therefore, the first nozzle opening can be formed into a desired shape with high precision. Also, the length of the first nozzle opening can be formed with high precision according to the thickness of the first nozzle layer.

[0083] In Mode 2, which is a specific example of Mode 1, the third step is performed after the second step. According to this, the second step and the third step can be performed from both sides of the substrate, and a high-precision nozzle can be formed.

[0084] In Mode 3, which is a specific example of Mode 2, after the second step, a fourth step of forming an oxide film so as to cover at least the first nozzle opening is performed, and the third step is performed after the fourth step. According to this, when performing the third step, etching of the first nozzle opening by the oxide film can be suppressed.

[0085] In Embodiment 4 which is a specific example of Embodiment 3, after the fourth step, a fifth step of thinning the second nozzle layer is further provided. According to this, by not thinning the first nozzle layer, the length of the first nozzle opening can be formed with high precision depending on the thickness of the first nozzle layer, and a nozzle plate with a desired thickness can be formed.

[0086] In Embodiment 5 which is a specific example of Embodiment 2, in the second step, a Bosch process is performed from the side of the first nozzle layer, and in the third step, a Bosch process is performed from the side of the second nozzle layer. According to this, the first nozzle opening and the second nozzle opening can be easily and highly precisely formed by the Bosch process.

[0087] In Embodiment 6 which is a specific example of Embodiment 1, the third step is performed after the first step and before the second step. According to this, the third step can be performed between the first step and the second step.

[0088] In Embodiment 7 which is a specific example of Embodiment 6, after the first step and before the third step, a fifth step of thinning the second nozzle layer is further provided. According to this, by not thinning the first nozzle layer, the length of the first nozzle opening can be formed with high precision depending on the thickness of the first nozzle layer, and a nozzle plate with a desired thickness can be formed.

[0089] In Embodiment 8 which is a specific example of Embodiment 6, in the second step and the third step, a Bosch process is performed from the side of the second nozzle layer. According to this, the Bosch process can be performed from the same side of the substrate to form the first nozzle opening and the second nozzle opening.

[0090] In Embodiment 9 which is a specific example of Embodiment 7, in the second step, the surface of the first nozzle layer on the side of the second nozzle layer is covered by the intermediate layer. According to this, when performing the second step, since the surface of the first nozzle layer is covered by the intermediate layer, it is possible to suppress the first nozzle layer from being etched when forming the second nozzle opening.

[0091] The liquid ejection head according to Embodiment 10, which is a preferred embodiment, is a liquid ejection head having a nozzle plate provided with nozzles and a pressure chamber substrate provided with a pressure chamber for applying pressure for ejecting liquid from the nozzles to the liquid. In the nozzle plate, a first nozzle layer formed of silicon, an intermediate layer formed of silicon oxide, and a second nozzle layer formed of silicon are laminated in this order. A first nozzle opening is provided in the first nozzle layer, a space portion communicating with the first nozzle opening is provided in the intermediate layer, and a second nozzle opening communicating with the space portion and having a diameter larger than that of the first nozzle opening is provided in the second nozzle layer. Scallops are formed in the first nozzle opening and the second nozzle opening, respectively, and no scallop is formed in the space portion.

[0092] According to this, the first nozzle opening and the second nozzle opening are formed with scallops, that is, they can be formed with high precision by a Bosch process. Also, since no scallop is formed in the space portion, that is, the space portion is formed in advance when forming at least one of the first nozzle opening and the second nozzle opening, no groove due to notching is formed in the space portion when forming at least one of the first nozzle opening and the second nozzle opening, and the nozzle can be formed with high precision.

[0093] In Embodiment 11, which is a specific example of Embodiment 10, the diameter of the space portion is larger than the diameter of the second nozzle opening. According to this, a recess is formed between the first nozzle opening and the second nozzle opening by the space portion. Foreign matter contained in the liquid is captured in the recess formed by this space portion, and clogging of the first nozzle opening due to foreign matter can be suppressed. Also, when the second nozzle layer side of the nozzle plate is adhered to another member, excess adhesive can be poured into the recess formed by the space portion, and the flow of the excess adhesive to the first nozzle opening side can be suppressed.

[0094] In Embodiment 12, which is a specific example of Embodiment 10, the diameter of the space portion is larger than the diameter of the first nozzle opening and smaller than the diameter of the second nozzle opening. According to this, since the diameter gradually decreases from the second nozzle opening toward the first nozzle opening, liquid can be ejected from the nozzle without inhibiting the flow of the liquid.

[0095] In Embodiment 13, which is a specific example of Embodiment 10, the diameter of the space portion is smaller than the diameter of the first nozzle opening. According to this, even if foreign matter enters from the first nozzle opening, the intermediate layer protruding more than the first nozzle opening can suppress the foreign matter from moving toward the second nozzle opening.

[0096] In Embodiment 14, which is a specific example of Embodiments 10 to 13, the intermediate layer is thinner than each of the first nozzle layer and the second nozzle layer. According to this, even if the intermediate layer is thin, it can function sufficiently during the manufacture of the nozzle plate.

[0097] In Embodiment 15, which is a specific example of Embodiment 14, the first nozzle layer is thinner than the second nozzle layer. According to this, the thickness of the first nozzle layer can define the length of the first nozzle opening, and the second nozzle layer can be used to adjust the thickness of the nozzle plate.

[0098] In Embodiment 16, which is a specific example of Embodiment 10, no groove is formed at the boundary between the first nozzle layer and the space portion. According to this, since no groove is formed in the first nozzle layer, the shape of the first nozzle opening can be formed with high precision.

[0099] In Embodiment 17, which is a specific example of Embodiment 16, a groove is formed at the boundary between the second nozzle layer and the space portion. According to this, a recess is formed between the first nozzle opening and the second nozzle opening by the groove. Foreign matter contained in the liquid can be captured in the recess formed by this groove, and clogging of the first nozzle opening due to foreign matter can be suppressed. Further, when the second nozzle layer side of the nozzle plate is adhered to another member, excess adhesive can be poured into the recess formed by the groove, and it is possible to suppress the excess adhesive from flowing into the first nozzle opening side. Furthermore, since the groove of the second nozzle opening has little influence on the injection characteristics of the nozzle, deterioration of the injection characteristics can be suppressed.

[0100] In Embodiment 18, which is a specific example of Embodiment 10, the diameter of the space portion at a position close to the second nozzle opening is larger than the diameter at a position close to the first nozzle opening. According to this, it is possible to form a recess on the side wall between the first nozzle opening and the second nozzle opening to capture foreign matter contained in the liquid and excess adhesive, and it is difficult to hinder the flow of the liquid.

[0101] The liquid injection device according to Embodiment 19, which is a preferred embodiment, includes the liquid injection head described in the above embodiment. According to this, it is possible to realize a liquid injection device that suppresses variations in injection characteristics and improves printing quality.

Explanation of Signs

[0102] H... Liquid ejection head, S... Medium, 1... Liquid ejection device, 3... Liquid storage section, 4... Control unit, 5... Conveying mechanism, 5a... Conveying roller, 6... Moving mechanism, 7... Holder, 8... Conveying belt, 10... Pressure chamber substrate, 12... Pressure chamber, 15... Communication plate, 16... Nozzle communication path, 17... First manifold section, 18... Second manifold section, 19... Supply communication path, 20... Nozzle plate, 21... First nozzle layer, 21a, 23a... Protective film, 22... Intermediate layer, 23... Second nozzle layer, 25... Nozzle, 26... First nozzle opening, 26a, 28a... Scallop, 27... Space section, 27a... First part, 27b... Second part, 28... Second nozzle opening, 29... Groove, 30... Protective substrate, 31... Accommodation section, 32... Through hole, 40... Case member, 41... Recess, 42... Third manifold section, 43... Connection port, 44... Inlet, 45... Compliance substrate, 46... Sealing film, 47... Fixed substrate, 48... Opening, 49... Compliance section, 50... Diaphragm, 51... Elastic film, 52... Insulator film, 60... First electrode, 70... Piezoelectric layer, 71... Recess, 80... Second electrode, 91... Individual lead electrode, 92... Common lead electrode, 100... Manifold, 110... Wiring member, 111... Drive signal selection circuit, 120... Substrate, 121... First region, 122, 123... Oxide film, 124... Second region, 300... Piezoelectric actuator, 310... Active section.

Claims

1. A method for manufacturing a nozzle plate provided with nozzles mounted on a liquid ejection head, comprising: a first step of preparing a substrate in which a first nozzle layer formed of silicon, an intermediate layer formed of silicon oxide, and a second nozzle layer formed of silicon are laminated in this order, and a space portion is provided in a part of the intermediate layer; a second step of performing a Bosch process on a first region where at least a part of the first nozzle layer overlaps with the space portion after the first step, and providing a first nozzle opening communicating with the space portion; a third step of performing a Bosch process on a second region where at least a part of the second nozzle layer overlaps with the space portion, and providing a second nozzle opening communicating with the space portion and having a diameter larger than that of the first nozzle opening; characterized by comprising: a method for manufacturing a nozzle plate.

2. The third step is performed after the second step. The method for manufacturing a nozzle plate according to claim 1, characterized by this.

3. a fourth step of forming an oxide film so as to cover at least the first nozzle opening after the second step; The third step is performed after the fourth step. The method for manufacturing a nozzle plate according to claim 2, characterized by this.

4. further comprising a fifth step of thinning the second nozzle layer after the fourth step. The method for manufacturing a nozzle plate according to claim 3, characterized by this.

5. In the second step, the Bosch process is performed from the side of the first nozzle layer. In the third step, the Bosch process is performed from the side of the second nozzle layer. The method for manufacturing a nozzle plate according to claim 2, characterized by this.

6. The third step is performed after the first step and before the second step. The method for manufacturing a nozzle plate according to claim 1, characterized by this.

7. further comprising a fifth step of thinning the second nozzle layer after the first step and before the third step. The method for manufacturing a nozzle plate according to claim 6, characterized by this.

8. In the second step and the third step, the Bosch process is performed from the side of the second nozzle layer. The method for manufacturing a nozzle plate according to claim 6, characterized by this.

9. In the second step, the surface of the first nozzle layer on the side of the second nozzle layer is covered by the intermediate layer. The method for manufacturing a nozzle plate according to claim 7, characterized by this.

10. a nozzle plate provided with nozzles; A pressure chamber substrate provided with a pressure chamber for applying pressure to a liquid to eject the liquid from a nozzle, A liquid ejection head having On the nozzle plate, a first nozzle layer formed of silicon, an intermediate layer formed of silicon oxide, and a second nozzle layer formed of silicon are laminated in this order, The first nozzle layer is provided with a first nozzle opening, The intermediate layer is provided with a space portion communicating with the first nozzle opening, The second nozzle layer is provided with a second nozzle opening communicating with the space portion and having a diameter larger than that of the first nozzle opening, Scallops are respectively formed in the first nozzle opening and the second nozzle opening, No scallop is formed in the space portion, A liquid ejection head characterized by the above.

11. The diameter of the space portion is larger than the diameter of the second nozzle opening, The liquid ejection head according to claim 10, characterized by the above.

12. The diameter of the space portion is larger than the diameter of the first nozzle opening and smaller than the diameter of the second nozzle opening, The liquid ejection head according to claim 10, characterized by the above.

13. The diameter of the space portion is smaller than the diameter of the first nozzle opening, The liquid ejection head according to claim 10, characterized by the above.

14. The intermediate layer is thinner than each of the first nozzle layer and the second nozzle layer, The liquid ejection head according to any one of claims 10 to 13, characterized by the above.

15. The first nozzle layer is thinner than the second nozzle layer, The liquid ejection head according to claim 14, characterized by the above.

16. No groove is formed at the boundary between the first nozzle layer and the space portion, The liquid ejection head according to claim 10, characterized by the above.

17. A groove is formed at the boundary between the second nozzle layer and the space portion, The liquid ejection head according to claim 16, characterized by the above.

18. The diameter of the space portion at a position closer to the second nozzle opening is larger than the diameter at a position closer to the first nozzle opening, The liquid ejection head according to claim 10, characterized by the above.

19. Comprising the liquid ejection head according to claim 10, A liquid ejection device characterized by the above.

Images