Nozzle plate, inkjet head, method for manufacturing nozzle plate, and method for manufacturing inkjet head

Abstract

When groove machining to provide a concave part 15 having a depth of 5 to 10 μm inclusive is performed in advance in a portion of a base material on which outer shape machining is to be performed and the outer shape machining is performed by a laser along the concave part 15 to manufacture a nozzle plate 10, the concave part 15 turns into a stepped part 151 and dross 152 is attached to the stepped part 151. Further, since the dross 152 is smaller than the stepped part 151, the dross 152 does not become a cause of a bonding failure or an occurrence of a void when the nozzle plate 10 is adhered to a flow path or the like.

Description

Technical Field

[0001] The present invention relates to a nozzle plate, an inkjet head, a method for manufacturing a nozzle plate, and a method for manufacturing an inkjet head.

Background Art

[0002] An inkjet head that discharges ink has a flow path substrate adhered to a nozzle plate, which is a substrate on which nozzles are formed, by an adhesive, and discharges ink from the nozzles. As a method for forming nozzles on a substrate, a method is known in which a tool is pushed into the substrate, a squeezing process is performed so that a recess reaches the back surface of the substrate, and then the convex portion on the back surface of the substrate is polished to transfer the shape of the tool so as to penetrate the substrate (see, for example, Patent Document 1).

[0003] As such a substrate for a nozzle plate, metals such as SUS (Steel Use Stainless) are used from the viewpoints of chemical stability against ink and durability against mechanical friction. As a method for processing the outer shape of a nozzle plate from a metal plate on which nozzles are formed, for example, wet etching with an etching solution (see Patent Document 2) and laser etching with a laser device (see Patent Document 3) are known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when performing contour machining by wet etching, the resist mask may enter the nozzle, and even if the resist is peeled off after contour machining, there is a risk that resist residues will remain in the nozzle.

[0006] Furthermore, when performing contour machining by laser etching, there is a risk of adhesion failure or voids caused by protrusions due to dross near the laser machining position. Although the generation of dross can be suppressed by using a laser device with short pulses such as picosecond or femtosecond lasers, compared with the generally used nanosecond pulse laser device, the device price is high, so there is a problem of inferior economy.

[0007] In addition, when adhering the flow path substrate to the nozzle plate, there is a risk of adhesion failure where the adhesive oozes out to the side surface.

[0008] The present invention has been made in view of such circumstances, and an object thereof is to provide a nozzle plate, an inkjet head, a method for manufacturing a nozzle plate, and a method for manufacturing an inkjet head that can suppress the occurrence of adhesion failure or voids during adhesion.

Means for Solving the Problems

[0009] In order to solve the above problems, the invention according to claim 1 is a nozzle plate of an inkjet head, The nozzle plate includes a first surface adhered to an upper layer substrate with an adhesive, and a second surface provided with openings of nozzles for discharging ink. The first surface has a step portion formed at an edge 、 The second surface has a planar edge .

[0010] The invention according to claim 2 is the nozzle plate according to claim 1, There is dross in the step portion formed .

[0011] The invention according to claim 3 is the nozzle plate according to claim 1 or 2, wherein the base material forming the nozzle plate is silicon or metal.

[0012] The invention according to claim 4 is the nozzle plate according to any one of claims 1 to 3, wherein the step portion has a depth of 5 μm or more and 10 μm or less in the central direction of the nozzle plate.

[0013] The invention according to claim 5 is an inkjet head, comprising the nozzle plate according to any one of claims 1 to 4.

[0014] The invention according to claim 6 is a method for manufacturing the nozzle plate according to any one of claims 1 to 4, comprising a groove machining step of forming a recess in a first surface of a single base material so as to form outer shapes of a plurality of nozzle plates, only a nozzle forming step of forming nozzles so that openings are formed in a second surface of the base material, and an outer shape machining step of cutting the recess by laser machining to cut out the nozzle plate from the base material.

[0015] The invention according to claim 7 is a method for manufacturing the nozzle plate according to claim 6, wherein the recess is formed by wet etching.

[0016] The invention according to claim 8 is a method for manufacturing the nozzle plate according to claim 6 or 7, comprising a water-repellent film forming step of forming a water-repellent film on the second surface.

[0017] The invention according to claim 9 is a method for manufacturing an inkjet head, comprising a nozzle plate manufacturing step of manufacturing the nozzle plate according to any one of claims 1 to 4, An adhesion step of adhering the first surface of the nozzle plate and the upper layer substrate with an adhesive; has.

Advantages of the Invention

[0018] According to the nozzle plate, the inkjet head including the nozzle plate, the manufacturing method of the nozzle plate, and the manufacturing method of the inkjet head of the present invention, it is possible to suppress the occurrence of adhesion failure or voids during adhesion.

Brief Description of the Drawings

[0019]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of the nozzle plate, the inkjet head including the nozzle plate, the manufacturing method of the nozzle plate, and the manufacturing method of the inkjet head according to the present invention will be described with reference to the drawings.

[0021] FIG. 1A is an overall view of the inkjet head 1 according to the present embodiment, and FIG. 1B is a cross-sectional view taken along line IB-IB when the inkjet head 1 of FIG. 1A is viewed from the side (-X direction side). In FIG. 1B, a cross-section of the inkjet head 1 at the plane including the four nozzles 14 included in the four nozzle rows is shown. The inkjet head 1 includes a head chip 2, a common ink chamber 70, a support substrate 80, a wiring member 3, a driving unit 4, and the like.

[0022] The head chip 2 is configured to eject ink from the nozzles 14, and a plurality (here, four) of plate-like substrates are laminated. The lowermost substrate in the head chip 2 is the nozzle plate 10. A plurality of nozzles 14 are formed in the nozzle plate 10, and ink can be ejected substantially perpendicular to the ink ejection surface (the exposed surface of the nozzle plate 10) where the openings of the nozzles 14 are provided. On the side opposite to the ink ejection surface of the nozzle plate 10, a pressure chamber substrate 20 (chamber plate), a spacer substrate 40, and a wiring substrate 50 are adhesively bonded and laminated in order upward (+Z direction). Hereinafter, each of these substrates, namely the nozzle plate 10, the pressure chamber substrate 20, the spacer substrate 40, and the wiring substrate 50, may also be referred to individually or collectively as flow path substrates 10, 20, 40, 50, etc.

[0023] These flow path substrates 10, 20, 40, 50 are provided with ink flow paths communicating with the nozzles 14, and are opened on the exposed side (+Z direction side) surface of the wiring substrate 50. A common ink chamber 70 is provided on the exposed surface of the wiring substrate 50 so as to cover all the openings. The common ink chamber 70 is provided with an ink supply unit 70a for supplying ink to the ink chamber forming member 70c and an ink discharge unit 70b for discharging the ink in the ink chamber forming member 70c at the upper part, respectively. The ink stored in the ink chamber forming member 70c of the common ink chamber 70 is supplied from the openings of the wiring substrate 50 to the respective nozzles 14.

[0024] A pressure chamber 21 is provided in the middle of the ink flow path. The pressure chamber 21 is provided so as to penetrate the pressure chamber substrate 20 in the vertical direction (Z direction). The upper surface of the pressure chamber 21 is constituted by a diaphragm 30 provided between the pressure chamber substrate 20 and the spacer substrate 40. The ink in the pressure chamber 21 is subjected to a pressure change by the deformation of the diaphragm 30 (pressure chamber 21) due to the displacement (deformation) of the piezoelectric element 60 in the storage portion 41 provided adjacent to the pressure chamber 21 via the diaphragm 30. By applying an appropriate pressure change to the ink in the pressure chamber 21, the ink in the ink flow path is discharged as droplets from the nozzles 14 communicating with the pressure chamber 21.

[0025] The support substrate 80 is joined to the upper surface of the head chip 2 and holds the ink chamber forming member 70c of the common ink chamber 70. The support substrate 80 is provided with an opening having substantially the same size and shape as the opening on the lower surface of the ink chamber forming member 70c. The ink in the common ink chamber 70 is supplied to the upper surface of the head chip 2 through the opening on the lower surface of the ink chamber forming member 70c and the opening of the support substrate 80.

[0026] The wiring member 3 is, for example, an FPC (Flexible Printed Circuits) or the like and is connected to the wiring of the wiring substrate 50. The piezoelectric element 60 is displaced by a drive signal transmitted through this wiring to the wiring 51 and the connection portion 52 (conductive member) in the storage portion 41. The wiring member 3 is drawn out through the support substrate 80 and connected to the drive portion 4.

[0027] The drive unit 4 receives a control signal from the control unit of the inkjet recording apparatus, power supply from the power supply unit, etc., and outputs an appropriate drive signal for the piezoelectric element 60 to the wiring member 3 according to the ink discharge operation and non-discharge operation from each nozzle 14. The drive unit 4 is constituted by an IC (Integrated Circuit) or the like.

[0028] FIG. 2 is a cross-sectional view showing the configuration of the nozzle plate 10. In FIG. 2, the cross-section of the nozzle plate 10 is shown enlarged.

[0029] The nozzle plate 10 is cut out from a base material and includes a substrate 11 provided with nozzles 14, a protective film 12 provided on the plate surface of the substrate 11 and the inner wall surface of the nozzles 14, a water-repellent film 13 formed by overlapping on the protective film 12 on the lower surface side of the substrate 11, a stepped portion 151 which is a notch provided at the edge, and a glue guard 16 provided on both sides of each nozzle 14. Hereinafter, the upper surface side of the substrate 11 will be referred to as the first surface 11a, and the lower surface side of the substrate 11 will be referred to as the second surface 11b.

[0030] The substrate 11 is a plate-shaped member cut out from a base material such as SUS (Steel Use Stainless, stainless steel) with a thickness of about 25 μm to 300 μm. By using SUS as the base material, a nozzle plate 10 excellent in chemical stability against ink and mechanical friction durability can be formed. As will be described later, when a silicon substrate is used as the substrate 11, a thermal oxide film may be formed on the outer layer of the substrate 11.

[0031] The nozzle 14 is a cylindrical hole having a circular opening on the second surface 11b of the substrate 11. The diameter of the opening of the nozzle 14 can be about 15 μm to 30 μm.

[0032] The protective film 12 is made of a material that does not dissolve by contact with ink. For example, in addition to silicon carbide (SiC), silicon carbonitride (SiOC), and silicon dioxide (SiO2), metal oxide films such as aluminum oxide (Al2O3), zirconium oxide (ZrO2), titanium oxide (TiO2), hafnium oxide (HfO2), and tantalum oxide (Ta2O3), and metal silicate films (such as tantalum silicate (TaSiO)) in which silicon is contained in the metal oxide film can be used. The thickness of the protective film 12 is not particularly limited, but is desirably about 50 nm to 500 nm, for example.

[0033] The protective film 12 made of such an ink-resistant material suppresses the substrate 11 from being eroded by ink (especially alkaline ink or acidic ink). Further, the protective film 12 may be used as an underlayer film for the water-repellent film 13 described later. Since the protective film 12 having ink resistance is unlikely to peel even when it comes into contact with ink, by using the protective film 12 as an underlayer film, it is possible to suppress the water-repellent film 13 from peeling together with the protective film 12 as the underlayer film.

[0034] The water-repellent film 13 is formed by overlapping it on the protective film 12, and its surface forms an ink ejection surface. The water-repellent film 13 is a layer provided to impart water repellency to ink and suppress the adhesion of ink and foreign matter. As the water-repellent film 13, it is formed by vapor-depositing a silane coupling agent having a perfluoroxyl group using the protective film 12 made of the material as described above as an underlayer film. Further, the water-repellent film 13 is provided with an opening penetrating the water-repellent film 13 at the formation position of the nozzle 14, and the ink ejected from the nozzle 14 is ejected from the opening.

[0035] The step portion 151 is a notch provided along the outer periphery of the first surface 11a, and dross 152 generated by laser processing described later is attached to the edge portion. The step portion 151 is a space that prevents the dross 152 generated when performing contour machining on the concave portion 15 of the nozzle plate 10 from inhibiting the adhesion between the nozzle plate 10 and the flow path substrate 20. Further, it becomes a space for accommodating the adhesive that has protruded from the end surface of the nozzle plate 10 when the nozzle plate 10 and the flow path substrate 20 are adhered. The depth of the step portion 151 is not particularly limited, but is preferably 5 μm to 10 μm.

[0036] The glue guard 16 is a concave groove portion provided substantially parallel to the row in which the nozzles 14 are formed. By providing the glue guard 16, when the nozzle plate 10 is adhered to the pressure chamber substrate 20, which is the upper layer substrate, with an adhesive, the risk of excess adhesive entering the nozzles 14 can be reduced. In FIG. 2, one guard 16 is provided on each side of the nozzle 14, but the position and number thereof are not limited thereto.

[0037] Next, a method for manufacturing the inkjet head 1 of the present embodiment will be described, centering on the method for manufacturing the nozzle plate 10. FIG. 3 is a flowchart showing the procedure of a process related to the manufacture of the nozzle plate 10 (nozzle plate manufacturing process). FIGS. 4A to 4D are a top view and a cross-sectional view taken along line A-B for explaining the nozzle plate manufacturing process. As shown in FIGS. 4A to 4D, according to the nozzle plate manufacturing process according to the present embodiment, a plurality of nozzle plates 10 can be manufactured simultaneously from a single substrate.

[0038] In the nozzle plate manufacturing process, first, as shown in FIG. 4A, groove processing (half etching) is performed on the portion of the first surface 11a of the substrate 11 where external shape processing will be performed in a later step S106 by wet etching to form the recess 15 (step S101).

[0039] As the wet etching process, a resist mask can be formed on the portion of the substrate 11 other than the portion where groove processing is to be performed, and the etching solution can be immersed. Note that the resist mask only needs to be able to protect the substrate 11 against the etching solution, and can be formed of an inorganic material such as silicon, for example. Further, as the etching solution, for example, when the substrate 11 is a SUS substrate, a neutral salt etching solution such as an aqueous solution containing ferric chloride (FeCl2) or cupric chloride (CuCl2) is generally used. When the substrate 11 is a silicon substrate, a mixed solution of nitric acid (HNO3) and hydrofluoric acid (HF) is generally used. However, it is not limited thereto, and it can be arbitrarily selected from known etching solutions. After the wet etching process, the resist mask is removed from the surface of the substrate 11.

[0040] In the groove processing step, a groove guard 16, which is a concave groove portion parallel to the row in which the nozzles 14 are formed, is simultaneously formed.

[0041] Next, as shown in FIG. 4B, punching is performed on the substrate 11 to form the nozzles 14 (step S102).

[0042] As the punching process, pressing is performed on the substrate 11 using a tool. Specifically, one surface of the tool provided with a nozzle forming portion is opposed to the first surface 11a of the substrate 11, and the nozzle forming portion is pressed against the first surface 11a to perform pressing. As a result, a nozzle recessed portion recessed toward the second surface 11b is formed in the first surface 11a, and a nozzle protruding portion is formed in the second surface 11b.

[0043] Next, the nozzle protruding portion protruding from the second surface 11b is polished and removed (step S103). Then, the nozzles 14 are opened in the second surface 11b. As a result, nozzles 14 penetrating from the first surface 11a to the second surface 11b are formed on the substrate 11.

[0044] Next, a protective film 12 is formed on the nozzle plate 10, and a water repellent film 13 is formed on the second surface 11b, which is the ink ejection surface side (step S104).

[0045] First, the surface of the substrate 11 is cleaned to remove foreign matter adhering to the substrate 11. The cleaning method of the substrate 11 can be, for example, US cleaning.

[0046] After the substrate 11 is cleaned, an ion bombardment treatment is performed on the surface of the substrate 11. The ion bombardment treatment is a treatment that physically acts on the member to be treated by colliding ions with the member to be treated in a reduced pressure environment. By such an ion bombardment treatment, impurities and a thin oxide film adhering to the surface of the substrate 11 are removed and purified, and the adhesion of the protective film 12 can be improved. Also, oxidation of the surface of the substrate 11 is suppressed.

[0047] After the ion bombardment treatment, a protective film 12 is formed on the surface of the substrate 11 by plasma CVD method, and the substrate 11 on which the protective film 12 is formed is washed to remove foreign matters adhering to the protective film 12. The cleaning method of the protective film 12 can be US cleaning as described above.

[0048] After cleaning the protective film 12, as shown in FIG. 4C, a water-repellent film 13 is formed on the protective film 12. The water-repellent film 13 is formed by a dry process typified by vacuum evaporation using, for example, a silane coupling agent having a perfluoroxyl group. As the silane coupling agent, aminosilane coupling agents such as γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, etc., and epoxy silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane are applicable. Note that the method for forming the water-repellent film 13 is not limited to this. For example, it may be formed based on conventionally known components and methods such as immersing the substrate 11 in a solution in which a fluorine-containing organosilicon compound is diluted with a fluorine-based solvent and then thermally drying it.

[0049] Next, the water-repellent film 13 formed on surfaces other than the second surface 11b is removed (step S105). Specifically, first, the second surface 11b is masked with a polyimide tape, the substrate 11 is placed in an ashing apparatus, and the water-repellent film 13 formed on surfaces other than the second surface 11b is removed by exposing it to O2 plasma for several tens of seconds. Then, the polyimide tape is removed and the substrate is washed. By the above method, a protective film 12 is formed on the entire surface of the substrate 11, and a water-repellent film 13 is formed only on the second surface 11b.

[0050] Next, as shown in FIG. 4D, the outer shape of the substrate 11 is processed by laser processing (outer shape processing step, step S106).

[0051] In the outer shape processing step, along the concave portion 15 of the substrate 11 where the groove processing was performed in step S101, which is the previous step, laser processing is performed using a laser device to cut the concave portion 15, thereby cutting out the nozzle plate 10 from the base material. As the laser light generated by the laser device, for example, excimer laser light or the like can be preferably exemplified. This is because excimer laser light has a short wavelength and enables preferable fine processing. The wavelength of the excimer laser light is in the range of 190 nm to 355 nm. Specifically, for example, ArF (wavelength 193 nm), KrF (248 nm), XeCl (wavelength 308 nm), XeF (wavelength 351 nm), etc. can be preferably mentioned. Note that, as the laser light, conventionally known ones such as YAG laser or CO2 laser may be used.

[0052] Since the laser processing in this step is performed by cutting the concave portion 15 of the nozzle plate 10 as described above, a stepped portion 151 as shown in FIG. 2 is formed at the edge of the nozzle plate 10 after the outer shape processing step. Also, usually, when the outer shape of the substrate 11 made of SUS is processed by laser processing, dross 152 is formed in the vicinity of the processed portion. However, in the present invention, since the laser processing is performed along the concave portion 15, as shown in FIG. 2, the dross 152 is formed at the edge of the stepped portion 151.

[0053] By the above method, a nozzle plate 10 having a stepped portion 151 with dross 152 attached is obtained at the edge of the substrate 11. The head chip 2 is manufactured by laminating the nozzle plate 10 and the flow path substrates 20, 40, 50, and is incorporated into a predetermined exterior member in combination with the common ink chamber 70, the support substrate 80, the wiring member 3, the drive portion 4, etc., thereby completing the inkjet head 1.

[0054] Subsequently, an experiment conducted to confirm the height of the dross formed in the outer shape processing of the above embodiment will be described.

[0055] In this experiment, the height of dross 152 formed when laser processing SUS was evaluated. Specifically, using SUS304HTA material with a thickness of 50 μm as the base material, and the MD-U1000C (manufactured by Keyence Corporation, wavelength: 355 nm, pulse width: 14 nsec, switch: 40 kHz, scan speed: 200 mm / sec), a solid-state laser device using a YVO4 crystal, laser processing was performed 20 scans for each level with the laser output (2.4 W / 1.8 W / 1.2 W / 0.6 W) and the presence or absence of assist gas changed. Next, after performing US cleaning with pure water for 20 minutes using 40 kHz ultrasonic waves, the height of dross 152 generated near the processed area was measured using the VK-X250 (manufactured by Keyence Corporation), a laser microscope, and the average value was calculated. Table I is a table showing the results of this experiment.

[0056]

Table 1

[0057] As shown in levels 1 - 3 of Table 1, as the laser output is decreased, the height of dross 152 can be lowered. However, as shown in levels 4 and 8, if the output is decreased to 0.6 W or less, external shape processing cannot be performed, which is not preferable. Also, as shown in levels 5 - 7, by using assist gas, the change in the height of dross 152 due to the change in laser output can be reduced, and it becomes stable with a height of 5 μm or less. As shown in Experiment 1, since the height of dross 152 generated during laser processing is about 5 μm, especially 10 μm or less, if the depth of step portion 151 is about 5 μm, dross 152 is less likely to cause adhesion failure or void generation when adhering to pressure chamber substrate 20. Also, if the depth of step portion 151 is about 10 μm, regardless of the conditions during laser processing, it is possible to prevent dross 152 from becoming an obstacle to adhesion after external shape processing.

[0058] As described above, the manufacturing method of the nozzle plate 10 according to the above embodiment includes at least a groove processing step of performing groove processing on a portion to be subjected to external shape processing by wet etching to form a plurality of recesses 15 in a single substrate, a nozzle forming step of forming a plurality of nozzles 14 by punching and polishing, and an external shape processing step of performing external shape processing of a plurality of nozzle plates 10 along the recesses 15 by laser processing. According to such a method, since the dross 152 generated in the external shape processing step is generated at the stepped portion 151 formed in the groove processing step, it is possible to suppress the occurrence of defects such as poor adhesion and void generation when the nozzle plate 10 is adhered to the pressure chamber substrate 20.

[0059] Further, in the manufacturing method of the nozzle plate 10 according to the above embodiment, in order to suppress the occurrence of such defects, it is not necessary to remove the dross 152 generated at the edge portion of the nozzle plate 10 by polishing. Therefore, the nozzle plate 10 can be manufactured efficiently and has excellent productivity.

[0060] Further, in the manufacturing method of the nozzle plate 10 according to the above embodiment, as shown in FIG. 4, each processing can be performed so as to manufacture a plurality of nozzle plates 10 from a single substrate 11. Therefore, a plurality of nozzle plates 10 can be manufactured efficiently and have excellent productivity.

[0061] Further, in the manufacturing method of the nozzle plate 10 according to the above embodiment, since the external shape processing is performed by laser processing, compared with the case where the external shape processing is performed by wet etching, steps such as the formation and removal of a resist mask are not required, and resist residues inside the nozzles 14 also do not occur. Therefore, the nozzle plate 10 can be manufactured efficiently and has excellent productivity.

[0062] Further, in the method for manufacturing the nozzle plate 10 according to the above embodiment, even if burrs 152 are generated during the external shape processing step, the occurrence of the above problems can be suppressed. Therefore, it is not necessary to use a short pulse laser device with a pulse width on the order of picoseconds or femtoseconds, and the nozzle plate 10 can be provided at low cost.

[0063] In addition, in the nozzle plate 10 manufactured by the manufacturing method according to the above embodiment, since burrs 152 are generated in the stepped portion 151, when adhering to the pressure chamber substrate 20, which is the upper layer substrate, with an adhesive, even if the amount of the adhesive is large, it is possible to prevent the burrs 152 from protruding to the side surface as a wall.

[0064] In addition, by using the nozzle plate 10 manufactured by the manufacturing method according to the above embodiment, the inkjet head 1 can be manufactured at low cost and efficiently, and has excellent productivity.

[0065] Note that the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the base material of the nozzle plate 10 is made of SUS, but it is not limited thereto. For example, a conventionally known material such as a silicon substrate or a metal such as Ni electroformed may be used.

[0066] In addition, in the above embodiment, an example in which the protective film 12 is formed on the entire surface of the substrate 11 has been described, but it is not limited thereto. The protective film 12 may be provided on at least a part of the surface of the substrate 11, that is, the first surface 11a and the inner wall surface of the nozzle 14 (that is, any range where ink may come into contact and which needs to have ink resistance).

[0067] In addition, the protective film 12 has a single-layer structure, but the configuration of the protective film 12 is not limited thereto, and a multi-layer structure may be used. Also, when the protective film 12 is not required, the nozzle plate 10 may not be provided with the protective film 12.

[0068] Further, the inner wall surface of the nozzle 14 may have a tapered shape such that the cross-sectional area parallel to the first surface 11a decreases as it approaches the opening of the nozzle 14.

[0069] Also, the nozzle 14 provided in the nozzle plate 10 may be configured to include a communication passage having an opening wider than the nozzle 14, an ink flow path for guiding ink that is discharged without being ejected from the nozzle 14, and the like. The shape of the nozzle 14 is not limited to the substantially frustum-conical shape shown in FIG. 2.

[0070] Further, when it is not necessary to impart water repellency to the ink ejection surface of the inkjet head 1, the nozzle plate 10 does not necessarily have to be provided with the water repellent film 13.

[0071] Also, in the above embodiment, the inkjet head 1 in the vent mode that discharges ink by varying the pressure of the ink in the pressure chamber 21 by deforming the piezoelectric element 60 has been described as an example, but the present invention is not limited to this. For example, the present invention may be applied to a shear mode inkjet head in which a pressure chamber is provided inside a piezoelectric body, and a shear mode displacement is generated in the piezoelectric body on the wall surface of the pressure chamber to vary the pressure of the ink in the pressure chamber. Also, the present invention is not limited to the method of deforming the pressure chamber. For example, the present invention may be applied to a thermal inkjet head that discharges ink by generating bubbles in the ink by heating.

[0072] Also, in the above embodiment, in the groove processing step, the concave portion 15 is formed by wet etching, but the present invention is not limited to this, and it may be formed by laser processing. However, when laser processing is performed, the base material may be distorted and warped, so it is preferably formed by wet etching.

[0073] Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, and includes the scope of the invention described in the claims and the equivalent scope thereof.

Industrial Applicability

[0074] The present invention can be used for a nozzle plate that suppresses the occurrence of poor adhesion or voids during adhesion.

Explanation of reference numerals

[0075] 1 Inkjet head 10 Nozzle plate 11a First surface 11b Second surface 13 Water-repellent film 14 Nozzle 15 Concave portion 20 Pressure chamber substrate (upper layer substrate) 151 Step portion 152 Dross

Claims

1. A nozzle plate of an inkjet head, wherein the nozzle plate has a first surface adhered to an upper substrate by an adhesive, and a second surface provided with openings of nozzles for ejecting ink, the first surface has a step formed at its edge, and the second surface is a nozzle plate with a planar edge.

2. The nozzle plate according to claim 1, wherein dross is formed on the step.

3. The nozzle plate according to claim 1 or 2, wherein the base material forming the nozzle plate is silicon or metal.

4. The nozzle plate according to any one of claims 1 to 3, wherein the step has a depth of 5 μm or more and 10 μm or less in the central direction of the nozzle plate.

5. An inkjet head comprising the nozzle plate according to any one of claims 1 to 4.

6. A method for manufacturing the nozzle plate according to any one of claims 1 to 4, the method comprising: a grooving step of forming a recess only on the first surface so as to form the outer shapes of a plurality of nozzle plates on one base material; a nozzle forming step of forming nozzles so that openings are formed on the second surface of the base material; and a profiling step of cutting the recess by laser processing to cut out the nozzle plate from the base material.

7. The method for manufacturing a nozzle plate according to claim 6, wherein the recess is formed by wet etching.

8. The method for manufacturing a nozzle plate according to claim 6 or 7, further comprising a water-repellent film forming step of forming a water-repellent film on the second surface.

9. A nozzle plate manufacturing step of manufacturing the nozzle plate according to any one of claims 1 to 4, and an adhesion step of adhering the first surface of the nozzle plate to an upper substrate with an adhesive. A method for manufacturing an inkjet head having the above steps.

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