Inkjet head

Abstract

An object of the present invention is to provide an inkjet head having excellent adhesion, ink resistance, and adhesion durability between structural components of the inkjet head. The inkjet head of the present invention is characterized in that it is composed of a component having a stainless steel substrate, a resin layer is provided on the stainless steel substrate, the surface or side surface portion of the resin layer is in contact with ink, and the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel substrate is 0.01 or more.

Description

Technical Field

[0001] The present invention relates to an inkjet head. More specifically, it relates to an inkjet head having excellent adhesion between components, ink resistance, and adhesion durability. Background Art

[0002] An inkjet recording apparatus that is now widely popular holds an inkjet head having a nozzle plate formed by arranging a plurality of nozzle holes in an array on a frame or the like, and ejects various color inks in the form of minute droplets from the plurality of nozzles toward a recording medium, thereby forming an image on the recording medium.

[0003] As a typical ink ejection method of an inkjet head, there are the following methods: a method in which heat is generated by passing an electric current through a resistor disposed in a pressure chamber, and the heat is used to vaporize and expand water in the ink to apply pressure to the ink to eject it; and a method in which a part of a flow path member constituting the pressure chamber is formed of a piezoelectric body or a piezoelectric body is provided in the flow path member, and the piezoelectric bodies corresponding to a plurality of nozzle holes are selectively driven, and based on the dynamic pressure of each piezoelectric body, the pressure chamber is deformed, thereby ejecting a liquid from the nozzle.

[0004] In an inkjet head, in order to achieve good ejection performance of ink droplets, the surface characteristics of the surface provided with the nozzles are very important.

[0005] If an ink liquid or debris adheres near the nozzle holes of the inkjet head, problems such as bending of the ejection direction of the ejected ink droplets or widening of the ejection angle of the ink droplets on the nozzle holes and generation of satellite droplets will occur.

[0006] In order to stably eject ink droplets, it is necessary to optimize the design in the ink flow path and the method of applying pressure to the ink, but this is not sufficient. It is also necessary to continuously maintain a stable surface state around the nozzle holes for ejecting ink. Therefore, a method of imparting a liquid-repellent layer having liquid-repellent properties to the periphery of the nozzle holes on the ink ejection surface of the nozzle plate has been studied to prevent the attachment or residue of unnecessary ink.

[0007] Generally, in a liquid-repellent film formed on the nozzle surface of a nozzle plate provided in an inkjet head, silicone-based compounds and fluorine-containing organic compounds can be used. For example, a silane coupling agent or the like can be used.

[0008] It is known that by using a silane coupling agent when forming a liquid-repellent layer, a liquid-repellent layer having excellent adhesion can be formed. However, when the density of hydroxyl groups in the base material and the base layer constituting the nozzle plate is low, since the basic components constituting the ink break the hydrogen bonds and hydroxyl bonds present therein and disconnect the bonds, there is a problem of a liquid-repellent layer having low alkali resistance.

[0009] Regarding the above problems, Patent Document 1 discloses an inkjet printer, characterized in that, as a surface treatment method for a nozzle member that can contribute to improving the corrosion resistance of the liquid contact portion of the inkjet head that comes into contact with ink, a CrNx compound layer composed of nitrogen and chromium is formed on the wall surface of the member that supplies liquid (ink) to the inkjet head, thereby being able to prevent corrosion of the components that come into contact with ink, such as the inner wall of the inkjet head or the inside of the ink supply pipe, and improve durability.

[0010] However, it has been found that the method proposed in Patent Document 1 has problems such as insufficient adhesion between the CrN layer and the base layer, and it is impossible to ensure durability (durability based on scratch durability, thermal stress, etc.).

[0011] Prior art documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-66510. Summary of the invention

[0014] The present invention has been completed in view of the above problems and situations, and the problem to be solved is to provide an inkjet head with excellent adhesion between components, ink resistance, and adhesion durability.

[0015] The present inventors have conducted repeated and in-depth studies in view of the above problems, and as a result, it has been found that by using an ink nozzle head having the following configuration, an ink head with excellent adhesion between components, ink resistance, and adhesion durability can be achieved, thus completing the present invention: The ink nozzle head is composed of a member having a stainless steel base material, a resin layer is provided on the stainless steel base material, the surface or side surface of the resin layer comes into contact with ink, the surface of the stainless steel base material has a Cr-containing layer, and the Cr-containing layer contains an Ar element in a specific ratio or more relative to the Cr element.

[0016] That is, the above problems of the present invention can be solved by the following method.

[0017] 1. An inkjet head composed of a member having a stainless steel base material, characterized in that

[0018] a resin layer is provided on the stainless steel base material, and the surface or side surface of the resin layer comes into contact with ink, and the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel base material is 0.01 or more.

[0019] 2. The inkjet head according to item 1, characterized in that the content ratio of trivalent Cr to the total Cr content in the surface portion of the stainless steel base material is 50 atm% or more.

[0020] 3. The inkjet head according to item 1 or item 2, characterized in that the ratio (Cr / Fe) of the concentration of Cr relative to Fe (atm%) among the constituent elements on the surface portion of the stainless steel substrate is 0.8 or more.

[0021] 4. The inkjet head according to any one of items 1 to 3, characterized in that a Cr-containing layer is provided on the surface of the stainless steel substrate, and the layer thickness of the Cr-containing layer is in the range of 5 to 50 nm.

[0022] 5. The inkjet head according to any one of items 1 to 4, characterized in that the component having the stainless steel substrate is a component constituting a nozzle plate, an ink flow path, an ink chamber, or an exterior portion that comes into contact with ink.

[0023] 6. The inkjet head according to any one of items 1 to 5, characterized in that the resin layer is composed of at least a polymerizable polymer.

[0024] 7. The inkjet head according to item 5, characterized in that the resin layer is a base layer and a liquid-repellent layer constituting the nozzle plate.

[0025] 8. The inkjet head according to item 7, characterized in that the base layer is a layer containing a silane coupling agent.

[0026] 9. The inkjet head according to item 8, characterized in that the silane coupling agent contained in the base layer has reactive functional groups at both ends and includes a hydrocarbon chain and a benzene ring in the middle portion.

[0027] 10. The inkjet head according to any one of items 7 to 9, characterized in that the liquid-repellent layer is a layer formed using a coupling agent having fluorine (F).

[0028] 11. The inkjet head according to any one of items 1 to 10, characterized in that the ink contains at least a colorant and 1 mass% or more of water.

[0029] 12. The inkjet head according to any one of items 1 to 11, characterized in that the ink is an alkaline ink.

[0030] Advantages of the Invention

[0031] According to the present invention, an inkjet head with excellent adhesion between components, ink resistance, and adhesion durability can be provided.

[0032] Regarding the working mechanism or action mechanism of the present invention, the following is speculated.

[0033] In the inkjet head of the present invention composed of components having a stainless steel substrate, it is characterized in that a resin layer is provided on the stainless steel substrate, and the surface or side surface of the resin layer is in contact with the ink, and the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel substrate is 0.01 or more.

[0034] Conventionally, in a hydrophobic film provided in a structural component of an inkjet head, for example, in a nozzle plate surface of an inkjet head, there has been a phenomenon that when applied to an ink having high interfacial permeability (for example, an alkaline ink) and in contact with the ink for a long time, peeling occurs at the interface between the nozzle hole periphery, the stainless steel substrate, and a functional layer formed thereon, such as a base layer, and this phenomenon becomes an important factor in reducing the adhesion durability.

[0035] In view of the above problems, the present inventors have repeatedly conducted in-depth research on solutions, and further pursued the technology of performing plasma treatment on the surface of the stainless steel substrate. As a result, it has been found that as a method of forming a functional layer on the surface of the stainless steel substrate, instead of performing O2 plasma treatment, Ar plasma treatment is performed to form a passive film on the stainless steel substrate, so that the structure of oxidized Cr has Ar elements, thereby achieving the above object. In addition, for Cr present on the surface of the stainless steel substrate, when it becomes a trivalent crystal state of surface-oxidized Cr, it shows stronger water-based ink resistance than in the case of a hexavalent crystal state. If it is such a liquid contact portion, not only for a hydrophobic resin film, but also for organic films such as an adhesive and a protective layer, the adhesion between the stainless steel substrate and the adjacent layer can be improved.

[0036] In addition, by setting the content ratio of trivalent Cr in the surface portion of the stainless steel substrate to 50 atm% or more with respect to the total Cr content, the adhesion durability can be significantly improved.

[0037] In addition, it has been found that by setting the ratio (Cr / Fe) of the concentration (atm%) of Cr to Fe as a concentration ratio of the structural elements in the surface portion of the stainless steel substrate to 0.8 or more, the above-mentioned alkaline ink resistance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic cross-sectional view showing an example of the structure of a nozzle plate as an example of a structural component of the inkjet head of the present invention.

[0039] Figure 2 It is a schematic cross-sectional view showing another example of the structure of a nozzle plate as an example of a structural component of the inkjet head of the present invention.

[0040] Figure 3 It is a schematic cross-sectional view showing an example of the structure of the nozzle hole portion of the nozzle plate.

[0041] Figure 4 is a schematic cross-sectional view showing an example of the structure of the inkjet head of the present invention.

[0042] Figure 5 is a schematic view showing an example of a high-frequency plasma device in RIE mode.

[0043] Figure 6 is a schematic view showing an example of a high-frequency plasma device in PE mode.

[0044] Figure 7 is a diagram showing an example of the distribution of Cr in different valence states in the surface portion of a stainless steel substrate.

[0045] Figure 8 is a simplified perspective view showing an example of the structure of an inkjet head capable of applying the nozzle plate of the present invention.

[0046] Figure 9 represents the composition of Figure 8 is a bottom view showing an example of the nozzle plate of the inkjet head shown. Detailed Embodiments

[0047] The inkjet head of the present invention is characterized in that it is an inkjet head composed of a component having a stainless steel substrate, a resin layer is provided on the stainless steel substrate, and the surface or side surface portion of the resin layer is in contact with the ink, and the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel substrate is 0.01 or more. This feature is a common technical feature in the inventions of the following respective embodiments.

[0048] As an embodiment of the present invention, from the viewpoint of further showing the object and effect of the present invention, the content rate (atm%) of trivalent Cr in the surface portion of the stainless steel substrate with respect to the total Cr content (atm%) is 50 atm% or more. At this time, the adhesion to the stainless steel substrate can be further improved, and more excellent adhesion durability can be shown, and it is preferable from this viewpoint.

[0049] In addition, in the ratio of the concentration (atm%) of the constituent elements in the surface portion of the stainless steel substrate, when the ratio (Cr / Fe) of the concentration (atm%) of Cr to Fe is 0.8 or more, it is preferable from the viewpoint of preventing the penetration of the ink to the interface between the stainless steel substrate and the base layer even when printing with an alkaline ink or the like for a long time, and further preventing the peeling between the stainless steel substrate and the base layer.

[0050] In addition, when the surface portion of the above-described stainless steel substrate has a Cr-containing layer and the layer thickness of the above-described Cr-containing layer is in the range of 1 to 50 nm, it is preferable from the viewpoint of further improving the alkali ink resistance in the inner surface portion of the nozzle hole of the nozzle plate, which is the object effect of the present invention.

[0051] In addition, when the component having a stainless steel substrate is a component constituting a nozzle plate, an ink flow path, an ink chamber, or an exterior portion that comes into contact with ink, it is preferable from the viewpoint of further demonstrating the object effect of the present invention.

[0052] In addition, when the resin layer is composed of at least a polymerizable polymer, it is preferable from the viewpoint of obtaining excellent adhesion with an adjacent layer.

[0053] In addition, when the resin layer is a base layer and a liquid-repellent layer constituting the above-described nozzle plate, it is preferable from the viewpoint of further demonstrating the effect of the present invention.

[0054] In addition, when the base layer is a layer having a silane coupling agent, from the viewpoint of improving the adhesion with the stainless steel substrate, improving the adhesion between the stainless steel substrate of the nozzle plate and the constituent layers provided thereon when the nozzle plate is stressed, particularly stressed in the thickness direction, improving the adhesion, and improving the adhesion durability when stressed in the thickness direction by a wiping material or the like used for maintaining the nozzle plate surface, it is preferable.

[0055] In addition, as the ink, an ink containing at least a coloring agent and containing 1% by mass or more of water, and when an alkali ink is used, the effect of the present invention can be further demonstrated.

[0056] Hereinafter, the present invention, its structural elements, and the modes and manners for implementing the present invention will be described in detail. It should be noted that in the present application, "~" indicating a numerical range is used to mean including the numerical values described before and after as the lower limit value and the upper limit value.

[0057] 《Inkjet Head》

[0058] The inkjet head of the present invention is characterized in that it is composed of a component having a stainless steel substrate, a resin layer is provided on the stainless steel substrate, the surface or side surface portion of the resin layer comes into contact with ink, and the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel substrate is 0.01 or more.

[0059] As a component that comes into contact with the ink constituting the inkjet head of the present invention, if it is composed of a component having a stainless steel substrate and a resin layer is provided on the stainless steel substrate, there is no particular limitation, and examples thereof include components constituting a nozzle plate, a nozzle substrate, an ink flow path, an ink chamber, or an exterior portion.

[0060] Hereinafter, as an example of a component that constitutes an inkjet head and comes into contact with ink, an example of a nozzle plate having a stainless steel substrate and a resin layer on the stainless steel substrate will be described.

[0061] Figure 1 FIG. is a schematic cross-sectional view showing an example of the structure of a nozzle plate, which is an example of a structural component of the inkjet head of the present invention.

[0062] As Figure 1 shown, the basic structure of the nozzle plate 1 is that on the surface of the stainless steel substrate 2, an Ar element of 0.01 or more is contained in terms of atm% with respect to the Cr element, and a resin layer 4 is provided thereon. Here, it is preferable that the resin layer 4 is composed of at least a polymerizable polymer.

[0063] Figure 2 FIG. is a schematic cross-sectional view showing another example of the structure of a nozzle plate, which is an example of a structural component of the inkjet head of the present invention.

[0064] Relative to Figure 1 the structure of the nozzle plate shown, Figure 2 the nozzle plate 1 shown in FIG. has a resin layer 4 formed on the surface portion 3 of the stainless steel substrate, and the resin layer 4 is composed of a base layer 5 and a liquid-repellent layer 6, and the base layer 5 is composed of a two-layer structure of a first base layer 5A and a second base layer 5B. For example, the first base layer 5A can be configured to contain a silane coupling agent (hereinafter, also simply referred to as silane coupling agent A) having reactive functional groups at both ends and a hydrocarbon chain and a benzene ring in the middle portion. As the second base layer 5B, it can be composed of an oxide mainly composed of carbon (C), silicon (Si), and oxygen (O), such as a low molecular weight silane compound or a silane coupling agent.

[0065] Figure 3 FIG. is a schematic cross-sectional view showing an example of a partial structure in which a nozzle hole is formed in the nozzle plate having the configuration defined in the present invention described above.

[0066] As Figure 3 shown, when a surface portion 3 containing an Ar element of 0.01 or more in terms of atm% with respect to the Cr element is provided between the stainless steel substrate 2 and the base layer 5, it is found that even when printing is performed for a long time using an ink such as an alkaline ink In, penetration of the ink In into the interface between the stainless steel substrate 2 and the base layer 5 can be prevented, and peeling between the stainless steel substrate 2 and the base layer 5 can be prevented. In addition, by setting the content ratio of trivalent Cr in the surface layer portion of the Cr-containing layer to 50 atm% or more with respect to the total Cr content, the adhesion durability can be significantly improved.

[0067] Also found that, as the concentration ratio of the structural elements of the surface portion 3, by setting the ratio (Cr / Fe) of the concentration (atm%) of Cr to Fe to 0.8 or more, the alkali ink resistance can be improved accordingly.

[0068] "Structure of Inkjet Head"

[0069] Next, the representative configuration of the inkjet head of the present invention will be described with reference to the drawings.

[0070] Figure 4 It is a schematic cross-sectional view showing an example of the structure of the inkjet head of the present invention.

[0071] The inkjet head 10 includes a nozzle chip 12, a holding portion 13, a common ink chamber 15, etc.

[0072] The nozzle chip 12 is formed by integrally laminating a nozzle plate 21 (hereinafter also referred to as a nozzle substrate), an intermediate substrate 22, an actuator substrate 23, and a protective substrate 24 in this order from the lower side inside.

[0073] In the nozzle substrate 21, nozzle holes N for ejecting ink droplets, a large-diameter portion 212 communicating with the nozzle holes N, and independent circulation channels 213 for ink circulation are formed.

[0074] In the intermediate substrate 22, a communication hole 221 penetrating the intermediate substrate 22 in the vertical direction and communicating with the large-diameter portion 212, and a common circulation channel 222 where ink flowing from a plurality of independent circulation channels 213 converges are formed.

[0075] In the actuator substrate 23, a pressure chamber 231 communicating with the through hole 221 and storing ink is formed.

[0076] In the protective substrate 24, a supply channel 241 penetrating in the vertical direction is formed to communicate the common supply liquid chamber 51 and the pressure chamber 231.

[0077] The common ink chamber 15 has a common supply liquid chamber 51 filled with ink.

[0078] In the upper part of the common ink chamber 15, a connection portion 11 is provided to supply ink supplied from the connection portion 11 to the nozzle chip 2.

[0079] Next, the ink circulation path inside the inkjet head 10 will be described. Ink is supplied from the connection portion 11 and flows in the order of the common supply liquid chamber 51 of the common ink chamber 15, the supply channel 241, the pressure chamber 231, the communication hole 221, the large-diameter portion 212, the independent circulation channels 213, the common circulation channel 222, and the connection portion 12, and is ejected outside the inkjet head 10.

[0080] Figure 4The arrow indicates the flow direction of the ink.

[0081] Therefore, the connecting portion 11, the common supply liquid chamber 51 of the common ink chamber 5, the supply flow path 241, the pressure chamber 231, the communication hole 221, the large-diameter portion 212, the independent circulation flow path 213, the common circulation flow path 222, and the connecting portion 12 constitute the flow path 200.

[0082] In such an inkjet head having a representative structure, a preferred form is that the component having a stainless steel substrate is a component constituting the nozzle plate, the nozzle substrate, the ink flow path, the ink chamber, or the exterior portion.

[0083] As Figure 4 shown, A is Figure 1 and Figure 2 the nozzle plate 21 having the structure described in Figure 3 , B is the nozzle hole N described in

[0084] [Each constituent material of the nozzle plate]

[0085] Next, the stainless steel substrate 2, the surface portion 3, the base layer 5, the liquid-repellent layer 6, etc. of the nozzle plate, which are representative parts constituting the print head of the present invention, will be described in detail.

[0086] [Stainless steel substrate]

[0087] Stainless steel (SUS) is used as the stainless steel substrate 2 constituting the nozzle plate. It is a material with high mechanical strength, excellent ink resistance, and excellent dimensional stability. As a representative stainless steel, SUS304, its average component composition in the state before the following treatment is Fe at 71 atm%, Cr at 18 atm%, Ni at 8.5 atm%, and the remainder is other elements.

[0088] The thickness of the stainless steel substrate constituting the nozzle plate is in the range of 10 to 500 μm, preferably in the range of 30 to 150 μm.

[0089] The present invention is characterized in that the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel substrate specified in the present invention is 0.01 or more. It should be noted that the surface portion of the stainless steel substrate described in the present invention refers to the region from the outermost surface of the substrate to a depth of 5 nm.

[0090] In addition, preferred embodiments include: the content ratio of trivalent Cr to the total Cr content in the surface portion 3 of the stainless steel substrate is 50 atm% or more; in the concentration ratio of the constituent elements of the surface layer portion of the Cr-containing layer, the ratio (Cr / Fe) of the concentration (atm%) of Cr to Fe is 0.8 or more; the surface portion of the stainless steel substrate contains a Cr-containing layer and the layer thickness of the Cr-containing layer is in the range of 1 to 50 nm.

[0091] The surface portion 3 of the present invention can be obtained by a method of performing surface treatment using an argon-based sputtering method (film formation method 1) on the surface of the stainless steel substrate, or by a method of forming a Cr-containing layer using Cr as a target material by sputtering on the stainless steel substrate and then performing surface treatment on the Cr-containing layer using an argon-based sputtering method (film formation method 2).

[0092] It is characterized in that the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr in the surface portion of the stainless steel substrate of the present invention formed between the stainless steel substrate and the base layer described later is 0.01 or more.

[0093] (Method for forming the Cr-containing layer)

[0094] In the present invention, a Cr-containing layer can be provided on the surface of the substrate, and there is no particular limitation on its formation method. Generally, it is preferably formed by the following method.

[0095] As the film formation method of the Cr-containing layer applicable in the present invention, physical vapor deposition methods (PVD methods), chemical vapor deposition methods (CVD methods) and other dry film formation methods, electroplating, electroless plating and other wet film formation methods can be cited. From the viewpoint of being able to form a dense film from a thin film, it is preferably formed by a dry film formation method in the present invention.

[0096] As the dry film formation method, sputtering method, vacuum evaporation method, laser ablation method, ion deposition method, molecular beam epitaxy method (MBE method), metalorganic chemical vapor deposition method (MOCVD method), plasma CVD method, plasma etching mode method using argon (Ar-PE mode), reactive ion etching method using argon (Ar-RIE mode), etc. can be cited. However, from the viewpoint of being able to form a dense film with a high Cr concentration from a thin film, the sputtering method, the reactive ion etching method using argon (Ar-RIE mode) and the method combining these methods are preferred.

[0097] In the present invention, from the aspect of being able to form a desired Cr-containing layer, it is preferable that in the method described above, after film formation by sputtering, a surface treatment is performed by plasma treatment.

[0098] (Specific film formation method 1 on the surface of a stainless steel substrate)

[0099] Hereinafter, film formation (film formation method 1) on the surface portion of a representative stainless steel substrate will be described.

[0100] As plasma etching modes applicable to the present invention, an RIE mode and a PE mode can be cited. The "RIE" (Reactive Ion Etching) mode described in the present invention is a method in which, in a pair of opposed flat electrodes, a stainless steel substrate such as SUS304 constituting a nozzle plate as an object to be plasma-treated is arranged on the power supply electrode side, and plasma treatment is performed on the surface of the object to be plasma-treated. On the other hand, the "PE" (Plasma Etching) mode is a method in which, in a pair of opposed flat electrodes, the object to be plasma-treated is arranged on the ground electrode side, and plasma treatment is performed on the surface of the object to be plasma-treated.

[0101] In addition, with reference to the drawings, the details of each plasma etching mode will be described.

[0102] 〈1: Ar-RIE mode plasma treatment apparatus〉

[0103] Figure 5 It is a schematic diagram showing an example of a high-frequency plasma apparatus of the RIE mode (reactive ion etching mode) used in the formation of a Cr-containing layer. The RIE mode is applicable to a physically high-speed surface treatment based on ion bombardment.

[0104] Figure 5 In it, the high-frequency plasma apparatus 20A of the RIE mode (hereinafter, also referred to as "plasma treatment apparatus 20A") includes a reaction chamber 21, a high-frequency power supply 22 (RF (Radio Frequency) power supply), a capacitor 23, a flat electrode 24 (also referred to as a cathode, "power supply electrode"), a counter electrode 25 (also referred to as an anode, "ground electrode"), a ground portion 26, etc. The reaction chamber 21 has a gas inlet 27 and an outlet 28. The flat electrode 24 and the counter electrode 25 are arranged in the reaction chamber 21.

[0105] A pair of electrodes composed of the flat electrode 24 connected to the high-frequency power supply 22 via the capacitor 23 and the counter electrode 25 opposed to the flat electrode 24 and grounded by the ground portion 26 are arranged in the closable reaction chamber 21. In addition, a nozzle plate substrate 30 as an object to be plasma-treated is arranged on the flat electrode 24.

[0106] First, air is sufficiently removed from the reaction chamber 21 via the gas outlet 28. In this state, while supplying Ar gas as the reaction gas G into the reaction chamber 21 via the gas inlet 27, the high-frequency power supply 22 is started, and power is supplied to the high-frequency power supply 22 at a high frequency of 3 MHz to 100 MHz (usually 13.56 MHz), thereby generating a discharge D between the planar electrode 24 and the counter electrode 25, and forming a discharge space 31 of a low-temperature plasma (cations and electrons) and radical species that generate the reaction gas G. At this time, as the high-frequency power density, it is preferably set within the range of 0.01 to 3 W / cm².

[0107] In the above configuration, due to the difference in the mobilities of ions and electrons, electrons are trapped by the planar electrode 24, causing the planar electrode 24 to be relatively negatively charged (self-bias). The electrons of the planar electrode 24 stop at the capacitor 23 via the power supply line 33. In addition, the electrons of the counter electrode 25 flow into the ground portion 26 via the power supply line 32.

[0108] On the other hand, radical species and cations are not easily trapped by the electrodes and move in the plasma. When the nozzle plate substrate 30 as the object to be processed is disposed on the planar electrode 24 in this plasma, an ion sheath that causes a strong electric field is generated on the side of the counter electrode 25 of the nozzle plate substrate 30, and an electric field of 400 to 1000 V is generated due to the cathode drop. The cations moving in the nozzle plate substrate 30 collide with or contact the surface portion of the nozzle plate substrate 30. Thus, the surface treatment of the object to be processed (etching here) is performed.

[0109] 〈2: Ar-PE mode plasma processing apparatus〉

[0110] Figure 6 It is a schematic diagram showing an example of a high-frequency plasma apparatus in the PE mode (plasma etching mode) used in the formation of the Cr-containing layer. The PE mode can achieve a mild treatment with less ion collision effect.

[0111] Figure 6 The basic configuration of the high-frequency plasma apparatus 20B in the PE mode shown (hereinafter, also referred to as "plasma processing apparatus 20B") is approximate to the high-frequency plasma apparatus 20A in the Ar-RIE mode described above Figure 5 but in the pair of opposing flat electrodes, on the side of the ground electrode 25, the nozzle plate substrate 30 as the object to be plasma-processed is disposed, and a method of performing plasma processing on the surface of the object to be plasma-processed.

[0112] In the present invention, this method using argon gas as the reaction gas is called "Ar-PE mode plasma processing".

[0113] (Specific film formation method 2 of Cr-containing layer)

[0114] Next, a representative Cr-containing layer film formation (film formation method 2) will be described.

[0115] 〈Forming a Cr-containing layer by sputtering method (film formation method 2)〉

[0116] In the sputtering method, Cr is used as a target, and sputtering film formation is carried out in an atmosphere such as argon, oxygen, and methane to form a Cr layer. The Cr content in the Cr layer formed by this sputtering method is approximately 100 atm%.

[0117] An example of a film formation method obtained by a specific sputtering method is shown below.

[0118] Under vacuum conditions, on the electrodes of a DC sputtering film formation apparatus, the pre-set Cr target is sputtered using the following conditions. At this time, it is not limited to DC sputtering, and other plasma sources can be used.

[0119] Target: Cr

[0120] DC power density: 1.1 W / cm 2

[0121] Power: RF power (13.56 MHz), 200 W

[0122] Temperature: 25 °C

[0123] Pressure: 0.3 Pa

[0124] Introduced gas: argon

[0125] Film formation time: 30 seconds

[0126] The layer thickness of the Cr-containing layer formed by the above sputtering method is 20 nm. As the layer thickness of the Cr-containing layer of the present invention, it is generally in the range of 1 to 5000 nm, and from the viewpoints of the alkali resistance of the nozzle plate and the workability in manufacturing the nozzle holes, it is preferably in the range of 5 to 50 nm.

[0127] Next, with respect to the Cr layer of approximately 100 atm% formed by the sputtering method, Ar plasma treatment described in the above film formation method 1 is carried out to form a Cr-containing layer having a desired atomic composition.

[0128] (Method for measuring characteristic values of the surface portion 3 of a stainless steel substrate)

[0129] The surface portion 3 of the stainless steel substrate of the present invention is characterized in that the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr is 0.01 or more. In addition, it is preferable that the content ratio of trivalent Cr to the total Cr content in the surface portion 3 of the stainless steel substrate is 50 atm% or more, and the ratio (Cr / Fe) of the concentration of Cr to the concentration of Fe in the concentration ratio of the constituent elements in the surface portion 3 of the stainless steel substrate is 0.8 or more.

[0130] Hereinafter, the detailed content of each characteristic value of the surface portion 3 of the stainless steel substrate of the present invention and its specific measurement method will be described.

[0131] 〈Measurement of the composition ratio of the structural elements of the surface portion 3 of the stainless steel substrate〉

[0132] In the present invention, the method for measuring the composition ratio and the like of the elements constituting the surface portion 3 of the stainless steel substrate is not particularly limited. In the present invention, for example, a method of using a trimming glass knife or the like to shave off a region of 10 nm from the surface of the Cr-containing layer for a sample having the surface portion 3 formed on the stainless steel substrate and quantitatively analyzing the composition of the material constituting the sliced portion; a method of quantifying by using a method such as infrared spectroscopy (IR), atomic absorption, etc. to scan the mass of compounds in the thickness direction of the Cr-containing layer, and even for an extremely thin film with a Cr-containing layer of 10 nm or less, quantification can be performed by XPS (X-ray Photoelectron Spectroscopy) analysis method. Among them, the XPS analysis method can perform elemental analysis even for an extremely thin film, and through the depth profile measurement described later, the composition distribution state in the entire layer thickness direction of the Cr-containing layer can be measured.

[0133] 〈Analysis method 1: Measurement of the content ratio of trivalent Cr in the surface portion 3 of the stainless steel substrate〉

[0134] The measurement method of the content ratio of trivalent Cr in the surface portion 3 of the stainless steel substrate of the present invention will be described.

[0135] In the surface portion 3 of the stainless steel substrate of the present invention, the content ratio of trivalent Cr to the total Cr content is preferably 50 atm% or more, and based on the method described below, the content ratio of trivalent Cr can be obtained.

[0136] In the present invention, when measuring the content ratios of each valence of 0-valent (metal monomer, Cr(0)), 3-valent (Cr(III), such as Cr2O3), and 6-valent (Cr(VI), such as CrO3) of Cr in the surface portion 3 of the stainless steel substrate, X-ray photoelectron spectroscopy analysis method is preferably used.

[0137] X-ray photoelectron spectroscopy is a method of analyzing the constituent atoms and their electron states existing in the surface region from the surface to a depth of 10 nm of a sample of the surface portion 3 of a stainless steel substrate, which is one of the photoelectron spectroscopies called XPS (X-ray Photoelectron Spectroscopy) or ESCA (Electron Spectroscopy for Chemical Analysis).

[0138] Hereinafter, an example of the specific conditions of XPS analysis that can be applied is shown.

[0139] · Analysis device: QUANTERA SXM manufactured by ULVAC-PHI

[0140] · X-ray source: Monochromatic Al-Kα 15 kV 25 W

[0141] · Pass energy: 55 eV

[0142] · Data processing: Use MultiPak manufactured by ULVAC-PHI

[0143] · Atomic composition analysis: Background processing is performed using the Shirley method, and the atomic composition is quantified using the relative sensitivity coefficient from the obtained peak area.

[0144] Cr valence state analysis: On the basis of correcting the peak shift due to charge based on the binding energy of the C 1s peak, for the Cr2p3 / 2 peak, the peaks of 0-valent, 3-valent, and 6-valent chromium are peak-separated. The binding energy of each state is 574.3 eV for 0-valent, 576.0 eV for 3-valent, and 578.9 eV for 6-valent. Using this value as the peak, fitting is performed under the condition that the FWHM of the peak is in the range of 1.2 to 2.8, and the ratios of 0-valent, 3-valent, and 6-valent chromium are obtained from the area ratio of each peak.

[0145] The above is a method for obtaining the content ratio of trivalent Cr in the surface portion (depth 5 nm) for a sample without a base layer and a liquid-repellent layer. However, for a sample with a base layer and a liquid-repellent layer, it is also possible to use GCIB (Gas Cluster Ion Beam) to remove the base layer and the liquid-repellent layer and then perform the above measurement to obtain the content of trivalent Cr in the surface portion 3 of the stainless steel substrate.

[0146] Using the above X-ray photoelectron spectroscopy, for example, it is possible to measure the content ratio (atm%) of each valence of Cr in the nozzle plate of the surface portion 3 of the stainless steel substrate formed by Cr sputtering and plasma treatment on the stainless steel substrate, and obtain the content ratio (atm%) of trivalent Cr relative to the total Cr content.

[0147] An example of the distribution of each valence number of Cr in the Cr-containing layer measured by the above method is shown in Figure 7 .

[0148] 〈Analysis method 2: Determination of the average composition ratio of each element in the Cr-containing layer〉

[0149] In the present invention, for a sample formed to the surface portion 3 of the stainless steel substrate, based on the content ratio (atm%) of trivalent Cr relative to the total Cr content (atm%), the average composition ratio (atm%) of each element (such as Cr, Fe, Ar, N, etc.) in the surface portion 3 of the stainless steel substrate is calculated. The average composition ratio is obtained by randomly measuring 10 points on the specimen and using the average value to calculate the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr and the ratio (Cr / Fe) of the concentration (atm%) of Cr to Fe in the surface portion 3 of the stainless steel substrate.

[0150] The analysis method 2 of the present invention is the same as the elemental composition analysis described in the above analysis method 1, but valence state analysis is not required, so there is no special regulation for "Pass energy". For a specimen on which a base layer and a liquid-repellent layer have been formed, the above measurement can be carried out on the basis of removing the base layer and the liquid-repellent layer using GCIB (gas cluster ion beam) in the same manner as in analysis method 1.

[0151] 〔Resin layer〕

[0152] The inkjet head of the present invention is characterized in that a resin layer is provided on the stainless steel substrate on which the Cr-containing layer is formed.

[0153] The resin layer of the present invention is more preferably composed of at least a polymerizable polymer.

[0154] (Polymerizable polymer)

[0155] As the polymerizable polymer of the present invention, there is no particular limitation, and general polymerizable polymers can be applied. For example, unsaturated polyester resins, epoxy resins, silicone resins, phenolic resins, polyimide resins, polyurethane resins, diallyl phthalate resins, etc. can be used.

[0156] Among the above polymerizable polymers, for example, when applied to the nozzle plate, as the structural material of the base layer and the liquid-repellent layer, the base layer is a layer formed using a silane coupling agent. The silane coupling agent contained in the base layer has reactive functional groups at both ends and contains a hydrocarbon chain and a benzene ring in the middle portion. The liquid-repellent layer is preferably a layer formed using a coupling agent having fluorine (F).

[0157] (Representative constitution example of the resin layer)

[0158] Hereinafter, the details of the base layer and the liquid-repellent layer that constitute the nozzle plate as a representative example of the resin layer will be described.

[0159] 〈Base layer〉

[0160] The base layer of the present invention is formed between the Cr-containing layer and the liquid-repellent layer of the present invention. As a more preferred form, as Figure 2 illustrated, it is a structure in which the base layer 5 is formed of a double-layer structure of a first base layer 5A and a second base layer 5B. For example, the first base layer 5A is formed with reactive functional groups at both ends and contains a silane coupling agent (hereinafter, also referred to as silane coupling agent A) containing a hydrocarbon chain and a benzene ring in the middle part. As the second base layer 5B, it can be composed of an oxide mainly composed of an Si-containing organic oxide, such as a low-molecular-weight silane compound or a silane coupling agent.

[0161] 〈1. Formation of the base layer based on silane coupling agent A: First base layer〉

[0162] In the present invention, as the silane coupling agent for forming the base layer by dehydration condensation reaction, a silane coupling agent A having reactive functional groups at both ends and containing a hydrocarbon chain and a benzene ring in the middle part is preferably used.

[0163] As the silane coupling agent A that can be applied to the base layer, there is no particular limitation, and the above-mentioned requirements known in the past can be appropriately selected and used. However, from the viewpoint of being able to effectively exert the object and effect of the present invention, a compound having an alkoxy group, chlorine, acyloxy group, or amino group as a reactive functional group at both ends shown in the following general formula (1) and having a structure containing a hydrocarbon chain and a benzene ring (phenylene group) in the middle part is preferably used.

[0164] 〈Compound having a structure represented by the general formula (1)〉

[0165] General formula (1)

[0166] X s Q 3-s Si(CH2) t C6H4(CH2) u SiR 3-m X m

[0167] In the above general formula (1), Q and R each represent a methyl group or an ethyl group. t and u each represent a natural number from 1 to 10. s and m each represent a natural number from 1 to 3. When s is 1 and m is 1, two Qs and two Rs exist respectively, and the two Qs and Rs can be of the same structure or different structures. C6H4 is a phenylene group. X represents an alkoxy group, chlorine, acyloxy group, or amino group.

[0168] As the alkoxy group, for example, there are alkoxy groups having 1 to 12 carbon atoms such as methoxy, ethoxy, propoxy, butoxy, etc., preferably alkoxy groups having 1 to 8 carbon atoms, more preferably alkoxy groups having 1 to 6 carbon atoms, etc.

[0169] In addition, as the acyloxy group, for example, there can be mentioned linear or branched acyloxy groups having 2 to 19 carbon atoms (such as acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, and octadecylcarbonyloxy, etc.).

[0170] In addition, as the amino group, there can be mentioned amino group (-NH2) and substituted amino groups having 1 to 15 carbon atoms (such as methylamino, dimethylamino, ethylamino, methylethylamino, diethylamino, n-propylamino, methyl-n-propylamino, ethyl-n-propylamino, n-propylamino, isopropylamino, isopropylmethylamino, isopropylethylamino, diisopropylamino, phenylamino, diphenylamino, methylphenylamino, ethylphenylamino, n-propylphenylamino, and isopropylphenylamino, etc.).

[0171] Hereinafter, exemplary compounds having the structure represented by the general formula (1) of the present invention are given, but the present invention is not limited to these exemplary compounds.

[0172] 1) 1,4-bis(trimethoxysilylethyl)benzene

[0173] 2) 1,4-bis(triethoxysilylethyl)benzene

[0174] 3) 1,4-bis(trimethoxysilylbutyl)benzene

[0175] 4) 1,4-bis(triethoxysilylbutyl)benzene

[0176] 5) 1,4-bis(trimethylaminosilylethyl)benzene

[0177] 6) 1,4-bis(triethylaminosilylethyl)benzene

[0178] 7) 1,4-bis(trimethylaminosilylbutyl)benzene

[0179] 7) 1,4-bis(triacetoxysilylethyl)benzene

[0180] 8) 1,4-bis(trichloromethylsilylethyl)benzene

[0181] 9) 1,4-bis(trichloroethylsilylethyl)benzene

[0182] The compound having the structure represented by the general formula (1) of the present invention can be synthesized based on the conventionally known synthesis methods. Additionally, it can be obtained as a commercially available product.

[0183] <2. Method for forming the base layer using silane coupling agent A>

[0184] The base layer of the present invention is formed by having reactive functional groups at both ends of the present invention, dissolving silane coupling agent A containing a hydrocarbon chain and a benzene ring in the middle part in an organic solvent such as ethanol, propanol, butanol, 2,2,2-trifluoroethanol, etc. to obtain a desired concentration, preparing a coating solution for forming the base layer, and then performing coating and drying on a stainless steel substrate having a Cr-containing layer by a wet coating method.

[0185] The concentration of silane coupling agent A as the coating solution for forming the base layer is not particularly limited, and is generally in the range of 0.5 to 50% by mass, preferably in the range of 1.0 to 30% by mass.

[0186] The layer thickness of the first base layer of the present invention is not particularly limited, and is preferably in the range of approximately 1 to 500 nm, more preferably in the range of 5 to 150 nm.

[0187] <3. Formation of the base layer composed of an oxide mainly containing Si-containing organic oxide: Second base layer>

[0188] In the base layer of the present invention, a preferred form is also a second base layer mainly composed of a Si-containing organic oxide.

[0189] Preferably as Figure 2 The preferred manner shown is that the base layer is composed of a base layer unit 4U based on the first base layer 6 and the second base layer 7. The first base layer 6 is composed of a first base layer having reactive functional groups at both ends described above and containing silane coupling agent A containing a hydrocarbon chain and a benzene ring in the middle part, and the second base layer 7 is formed as a second base layer composed of a Si-containing organic oxide described below.

[0190] In the base layer of the present invention, the compound constituting the layer mainly containing a Si-containing organic oxide can be silane coupling agent A applied in the above base layer.

[0191] Although an example of an alkoxysilane, silazane, or silane coupling agent having a molecular weight of 300 or less applicable in the present invention is shown, it is not limited to these exemplified compounds. It should be noted that the values described in parentheses after each compound are the molecular weight (Mw).

[0192] As alkoxysilanes, for example, silicon nitride oxide film (Si(OC2H5)4, Mw: 208.3), methyltriethoxysilane (CH3Si(OC2H5)3, Mw: 178.3), methyltrimethoxysilane (CH3Si(OCH3)3, Mw: 136.2), dimethyldiethoxysilane ((CH3)2Si(OC2H5)2, Mw: 148.3), dimethyldimethoxysilane ((CH3)2Si(OCH3)2, Mw: 120.2), etc. can be cited.

[0193] In addition, as silazanes, for example, 1,1,1,3,3,3 - hexamethyldisilazane ((CH3)3SiNHSi(CH3)3, 161.4), 1,1,1,3,3,3 - hexaethyldisilazane ((C2H5)3SiNHSi(C2H5)3, 245.4) can be cited. In addition, 1,3 - bis(chloromethyl)tetramethyldisilazane, 1,3 - divinyl - 1,1,3,3 - tetramethyldisilazane, etc. can be cited.

[0194] In addition, as silane coupling agents, 1) vinyl - based silane coupling agents can be cited: vinyltrimethoxysilane (CH2 = CHSi(OCH3)3, Mw: 148.2), vinyltriethoxysilane (CH2 = CHSi(OC2H5)3, Mw: 190.3). In addition, CH2 = CHSi(CH3)(OCH3)2, CH2 = CHCOO(CH2)2Si(OCH3)3, CH2 = CHCOO(CH2)2Si(CH3)Cl2, CH2 = CHCOO(CH2)3SiCl3, CH2 = C(CH3)Si(OC2H5)3, etc. can be cited.

[0195] 2) Amino - based silane coupling agents can be cited: 3 - aminopropyltrimethoxysilane (H2NCH2CH2CH2Si(OCH3)3, mW: 179.3), 3 - (2 - aminoethylamino)propyltrimethoxysilane (H2NCH2CH2NHCH2CH2CH2Si(OCH3)3, Mw: 222.4), 3 - (2 - aminoethylamino)propylmethyldimethoxysilane (H2NCH2CH2NHCH2CH2CH2Si(CH3)(OCH3)2, Mw: 206.4), etc.

[0196] 3) Epoxy - type silane coupling agents can be cited: 3 - glycidoxypropyltrimethoxysilane (Mw: 236.3), 3 - glycidoxypropyltriethoxysilane (Mw: 278.4), etc.

[0197] 〈4. Method for forming the second base layer〉

[0198] The second base layer of the present invention can be formed by dissolving a silane compound having a molecular weight of 300 or less according to the present invention, such as an alkoxysilane, a silazane, or a silane coupling agent C, in an organic solvent such as ethanol, propanol, butanol, 2,2,2-trifluoroethanol, etc. to obtain a desired concentration, preparing a coating liquid for forming an intermediate layer, and then performing coating and drying on the base layer by a wet coating method.

[0199] There is no particular limitation on the concentration of the material for forming an inorganic oxide as the coating liquid for forming the second base layer, and it is generally in the range of 0.5 to 50% by mass, preferably in the range of 1.0 to 30% by mass.

[0200] The layer thickness of the second base of the present invention is in the range of 0.5 to 500 nm, preferably in the range of 1 to 300 nm, and more preferably in the range of 5 to 100 nm.

[0201] (Liquid-repellent layer)

[0202] In the present invention, the liquid-repellent layer preferably contains a coupling agent having fluorine (F) (hereinafter, also referred to as coupling agent B).

[0203] There is no particular limitation on the coupling agent B having fluorine (F) that can be applied in the liquid-repellent layer of the present invention. It preferably contains a fluorine-based compound, and the fluorine-based compound preferably includes (1) a compound having a perfluoroalkyl group containing at least an alkoxysilyl group, a phosphonic acid group, or a hydroxyl group, or a compound having a perfluoropolyether group containing an alkoxysilyl group, a phosphonic acid group, or a hydroxyl group, or (2) a mixture containing a compound having a perfluoroalkyl group, or a mixture containing a compound having a perfluoropolyether group.

[0204] Specific compounds of coupling agent B having fluorine (F) that can be applied in the lyophobic layer of the present invention include chlorodimethyl[3-(2,3,4,5,6-pentafluorophenyl)propyl]silane, pentafluorophenyldimethylchlorosilane, pentafluorophenylethyoxydimethylsilane, pentafluorophenylethyoxydimethylsilane, trichloro(1H,1H,2H,2H-tridecafluoro-n-octyl)silane, trichloro(1H,1H,2H,2H-heptadecafluorodecyl)silane, trimethoxy(3,3,3-trifluoropropyl)silane, triethoxy(1H,1H,2H,2H-nonafluorohexyl)silane, triethoxy-1H,1H,2H,2H-heptadecafluorodecylsilane, trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane, trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane, trichloro[3-(pentafluorophenyl)propyl]silane, trimethoxy(11-pentafluorophenoxoundecyl)silane, triethoxy[5,5,6,6,7,7,7-heptafluoro-4,4-bis(trifluoromethyl)heptyl]silane, trimethoxy(pentafluorophenyl)silane, triethoxy(1H,1H,2H,2H-nonafluorohexyl)silane, γ-glycidoxypropyltrimethoxysilane, and the like.

[0205] In addition, silane coupling agents having fluorine (F) can also be obtained as commercial products. For example, they are sold by Dow Corning silicone Co., Ltd., Shin-Etsu Chemical Co., Ltd., Daikin Industries, Ltd. (e.g., OPTOOL DSX), Asahi Glass Co., Ltd. (e.g., CYTOP), or SECO Co., Ltd. (e.g., Top CleanSafe (registered trademark)), Fluorotechnology Co., Ltd. (e.g., FluoSurf), Gelest Inc., Solvay Solexis Co., Ltd. (e.g., Fluorolink S10), etc., and can be easily obtained. In addition, for example, compounds described in J. Fluorine Chem., 79(1).87(1996), Materials Technology, 16(5), 209(1998), Collect. Czech. Chem. Commun., Vol. 44, pp. 750 - 755, J. Amer. Chem. Soc. in 1990, Vol. 112, pp. 2341 - 2348, Inorg. Chem., Vol. 10, pp. 889 - 892, in 1971, U.S. Patent No. 3668233 specification, etc. can be cited. In addition, they can be manufactured by the synthesis methods described in each of the gazettes of Japanese Patent Application Laid-Open No. 58-122979, Japanese Patent Application Laid-Open No. 7-242675, Japanese Patent Application Laid-Open No. 9-61605, No. 11-29585, Japanese Patent Application Laid-Open No. 2000-64348, No. 2000-144097, etc. or synthesis methods based thereon.

[0206] Specifically, as the compound having a silyl-terminated perfluoropolyether group, for example, "OPTOOL DSX" manufactured by Daikin Industries, Ltd. as shown above can be cited. As the compound having a silyl-terminated fluoroalkyl group, for example, "FG-5010Z130-0.2" manufactured by FluoSurf Corporation, etc. can be cited. As the polymer having a perfluoroalkyl group, for example, "SF-COAT series" manufactured by AGCSEIMI CHEMICAL Co., Ltd. can be cited. As the polymer having a fluorine-containing heterocyclic structure in the main chain, for example, "CYTOP" manufactured by the above-mentioned Asahi Glass Company, etc. can be cited. In addition, a mixture of an FEP (tetrafluoroethylene - hexafluoropropylene copolymer) dispersion and a polyamideimide resin can also be cited.

[0207] The layer thickness of the liquid-repellent layer of the present invention is generally in the range of 1 to 500 nm, preferably in the range of 1 to 400 nm, and more preferably in the range of 2 to 200 nm.

[0208] 〔Processing of nozzle plate〕

[0209] As a method for manufacturing the nozzle plate of the present invention,

[0210] The details are as described above: For example:

[0211] 1) For the above nozzle plate, a resin layer is formed on a stainless steel substrate.

[0212] 2) On the surface of the above stainless steel substrate, a Cr-containing layer with a ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr of 0.01 or more is formed.

[0213] 4) On the Cr-containing layer, a base layer is formed through the dehydration condensation reaction of a silane coupling agent, and

[0214] 5) A method of forming the above liquid-repellent layer using a coupling agent having fluorine (F).

[0215] The above Figure 3 The nozzle plate 1 shown is a schematic cross-sectional view showing an example of the structure of the nozzle hole portion of the nozzle plate of the present invention.

[0216] As Figure 2 shown, for the nozzle plate 1, a nozzle portion N having a desired shape as an ink ejection portion is formed.

[0217] Regarding the specific method for forming nozzle holes and the like in the nozzle plate of the present invention, for example, reference can be made to the methods described in Japanese Patent Publication No. 2005-533662, Japanese Patent Application Laid-Open No. 2007-152871, Japanese Patent Application Laid-Open No. 2007-313701, Japanese Patent Application Laid-Open No. 2009-255341, Japanese Patent Application Laid-Open No. 2009-274415, Japanese Patent Application Laid-Open No. 2009-286036, Japanese Patent Application Laid-Open No. 2010-023446, Japanese Patent Application Laid-Open No. 2011-011425, Japanese Patent Application Laid-Open No. 2013-202886, Japanese Patent Application Laid-Open No. 2014-144485, Japanese Patent Application Laid-Open No. 2018-083316, Japanese Patent Application Laid-Open No. 2018-111208, etc. The detailed description thereof is omitted here.

[0218] Figure 2 The structure of the nozzle plate of the present invention is such that by forming a surface portion 3 on the surface of the stainless steel substrate 2 where the ratio (Ar / Cr) of the concentration (atm%) of Ar to Cr is 0.01 or more, it is possible to prevent interfacial damage caused by the ink liquid In and obtain a nozzle plate with high durability.

[0219] In the nozzle plate of the present invention, it is preferable to form the nozzle holes by laser processing.

[0220] In the nozzle plate of the present invention, as the manufacturing method, it is preferable to use a laser in the external shape processing of the nozzle holes, and it is further preferable that the laser is a pulsed laser or a CW laser.

[0221] As the lasers that can be applied in the manufacture of the nozzle plate of the present invention, it is preferable to use a continuously oscillating laser beam (CW laser beam) and a pulsed oscillating laser beam (pulsed laser beam).

[0222] The laser beams that can be used here include gas lasers such as Ar laser, Kr laser, and excimer laser, single-crystal YAG, YVO4, forsterite (Mg2SiO4), YAlO3, GdVO4, YLF, or polycrystalline (ceramic) YAG, Y2O3, YVO4, YAlO3, GdVO4. As the dopant, lasers obtained by adding one or more substances among Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta as the medium, glass laser, ruby laser, alexandrite laser, Ti:sapphire laser, copper vapor laser, or gold vapor laser can be mentioned.

[0223] Among these, it is preferable to use a laser that emits ultraviolet laser with a wavelength of about 266 nm, such as YAG-UV (yttrium-aluminum-garnet crystal: wavelength 266 nm), YVO4 (wavelength: 355 nm). Especially when the object to be processed is an organic material, among the lasers with a wavelength of about 266 nm, molecular bonds such as C-H bonds and C-C bonds can be dissociated by thermal action.

[0224] As an example of the irradiation conditions, for example, in YAG-UV (wavelength 266 nm), the pulse width is 12 nsec and the output is 1.6 W. In the case of YVO4 (wavelength: 355 nm), the pulse width is 18 nsec and the output is 2.4 W.

[0225] In addition, it is also possible to use an ultrafast laser that generates a strong laser pulse with a duration approximately from 10 -11 seconds (10 picoseconds) to 10 -14 seconds (10 femtoseconds), or a short-pulse laser that generates a strong laser pulse with a duration approximately from 10 -10 seconds (100 picoseconds) to 10 -11 seconds (10 picoseconds). These pulsed lasers are also useful for cutting or drilling a wide range of materials.

[0226] 《Inkjet Head》

[0227] Figure 8 is a schematic external view showing an example of the structure of an inkjet head that can use the nozzle plate of the present invention. In addition, Figure 9 is a bottom view of an inkjet head equipped with the nozzle plate of the present invention.

[0228] As Figure 8 shown, the inkjet head 100 equipped with the nozzle plate of the present invention is mounted on an inkjet printer (not shown), and includes a printhead chip that ejects ink from nozzles; a wiring substrate on which the printhead chip is disposed; a drive circuit substrate connected via the wiring substrate and a flexible substrate; a manifold that introduces ink into the channels of the printhead chip via a filter; a housing 56 that houses the manifold inside; a cover receiving plate installed to block the bottom opening of the housing 56; a first joint 81a and a second joint 81b installed on the first ink port and the second ink port of the manifold; a third joint 82 installed on the third ink port of the manifold; and a cover member 59 installed on the housing 56. In addition, mounting holes 68 for mounting the housing 56 on the printer main body side are respectively formed.

[0229] In addition, Figure 9The shown cover receiving plate 57 corresponds to the shape of the cover receiving plate mounting portion 62, and its outer shape is formed into a substantially rectangular plate shape that is long in the left-right direction, exposing the nozzle plate 61 having a plurality of nozzles N disposed at a substantially central portion thereof. Thus, a long nozzle opening portion 71 is provided in the left-right direction. In addition, regarding Figure 8 the specific structure inside the inkjet head shown in Figure 2 etc., for example, reference can be made to that described in Japanese Patent Application Laid-Open No. 2012-140017

[0230] Figure 8 and Figure 9 representative examples of the inkjet head are shown. However, in addition to these, for example, an inkjet head configured by appropriately selecting and applying the structures described in Japanese Patent Application Laid-Open No. 2012-140017, Japanese Patent Application Laid-Open No. 2013-010227, Japanese Patent Application Laid-Open No. 2014-058171, Japanese Patent Application Laid-Open No. 2014-097644, Japanese Patent Application Laid-Open No. 2015-142979, Japanese Patent Application Laid-Open No. 2015-142980, Japanese Patent Application Laid-Open No. 2016-002675, Japanese Patent Application Laid-Open No. 2016-002682, Japanese Patent Application Laid-Open No. 2016-107401, Japanese Patent Application Laid-Open No. 2017-109476, Japanese Patent Application Laid-Open No. 2017-177626, etc. can be used.

[0231] "Inkjet Ink"

[0232] The inkjet ink applicable to the inkjet recording method using the inkjet head of the present invention is not particularly limited. For example, there are water-based inkjet inks mainly using water as a solvent, oil-based inkjet inks that are substantially free of water and mainly use a non-volatile solvent that does not volatilize at room temperature, organic solvent-based inkjet inks that are substantially free of water and mainly use a volatile solvent at room temperature, hot melt inks printed by heating and melting a solid ink at room temperature, active energy ray-curable inkjet inks cured by active rays such as ultraviolet rays after printing, and various other inkjet inks. However, in the present invention, from the viewpoint of being able to exhibit the effects of the present invention, an alkali ink is preferably used.

[0233] The ink, for example, has an alkali ink and an acidic ink. In particular, the alkali ink may cause chemical deterioration of the substrate, the liquid-repellent layer, and the nozzle formation surface. Thus, it is particularly effective to apply the inkjet head having the nozzle plate of the present invention in an inkjet recording method using such an alkali ink.

[0234] Specifically, the ink that can be applied in the present invention contains colorants such as dyes and pigments, water, water-soluble organic solvents, pH adjusters, etc. Examples of the water-soluble organic solvents that can be used include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerol, triethylene glycol, ethanol, propanol, etc. Examples of the pH adjusters that can be used include sodium hydroxide, potassium hydroxide, sodium acetate, sodium carbonate, sodium bicarbonate, alkanolamine, hydrochloric acid, acetic acid, etc.

[0235] When sodium hydroxide, potassium hydroxide, sodium acetate, sodium carbonate, sodium bicarbonate, alkanolamine, etc. are used as the pH adjuster, the ink is alkaline and becomes an alkaline ink (liquid) that may cause chemical damage (chemical deterioration) to the liquid-repellent layer and the nozzle formation surface. The pH of the alkaline ink is 8.0 or higher.

[0236] As described above, the liquid-repellent layer is formed of a fluorine-containing silane coupling agent, etc. The partial structure containing silicon and the partial structure containing fluorine in the liquid-repellent layer have a structure bonded by a substituent such as methylene (CH2). The binding energy between carbon (C) and carbon (C) is smaller than the binding energy between silicon (Si) and oxygen (O) and the binding energy between carbon (C) and fluorine (F). Therefore, the part where carbon (C) is bonded to carbon (C) is weaker in binding than the part where silicon (Si) is bonded to oxygen (O) and the part where carbon (C) is bonded to fluorine (F), and is easily affected by mechanical damage and chemical damage.

[0237] In the inkjet recording method using the alkaline ink that is likely to cause such a phenomenon, the nozzle plate having the configuration defined in the present invention is effective from the viewpoint of improving durability.

[0238] Examples

[0239] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. It should be noted that in the examples, the expressions "parts" or "%" represent "parts by mass" or "% by mass" unless otherwise specified. In addition, unless otherwise noted, each operation is performed at room temperature (25°C).

[0240] Example 1

[0241] 《Fabrication of Nozzle Plate》

[0242] [Fabrication of Nozzle Plate 1]

[0243] Based on the following method, a nozzle plate 1 composed of Figure 2 the stainless steel substrate 2 / surface portion 3 / first base layer 5A / second base layer 5B / liquid-repellent layer 6 described in the text was fabricated.

[0244] (1) Preparation of Stainless Steel Substrate

[0245] As the base material, a stainless steel base material (SUS304) that does not undergo surface treatment with a length of 3 cm, a width of 8 cm, and a thickness of 50 μm is used.

[0246] (2) Formation of the first layer (Cr-containing layer)

[0247] 〈Step 1: Formation of the Cr layer by sputtering〉

[0248] As the sputtering method, Cr is used as the target, and sputter deposition is performed on the stainless steel base material in an argon atmosphere to form a single Cr metal layer. The content of Cr in the Cr layer formed by this sputtering method is approximately 100 atm%.

[0249] Specifically, under vacuum conditions, the placed Cr target on the electrode of the DC sputter deposition apparatus is sputtered using the following conditions.

[0250] Target: Cr

[0251] DC power density: 1.1 W / cm 2

[0252] Power: RF power (13.56 MHz), 200 W

[0253] Temperature: 25 °C

[0254] Pressure: 0.3 Pa

[0255] Introduced gas: Argon

[0256] Film deposition time: 30 seconds

[0257] Layer thickness: 20 nm

[0258] 〈Step 2: Etching using the Ar-RIE plasma mode〉

[0259] Next, the stainless steel base material on which the Cr layer is formed in Step 1 is subjected to an etching process based on the Ar-RIE plasma mode using the following method to form a Cr-containing layer.

[0260] Use the Figure 5 RIE-mode high-frequency plasma apparatus with the structure described above to perform Ar plasma treatment on the Cr layer to form a Cr-containing layer with a layer thickness of 20 nm.

[0261] The plasma treatment conditions are as follows.

[0262] Plasma treatment apparatus: RIE-mode high-frequency plasma apparatus

[0263] Reaction gas G: Argon

[0264] Gas flow rate: 50 sccm

[0265] Gas pressure: 10 Pa

[0266] High-frequency power: 13.56 MHz

[0267] High-frequency power density: 0.10 W / cm 2

[0268] Voltage between electrodes: 450 W

[0269] Processing time: 3 minutes

[0270] Substrate processing temperature: 80 °C or below

[0271] (3) Formation of the second layer (first base layer)

[0272] (Preparation of coating liquid for forming the first base layer)

[0273] (Preparation of Solution A-1)

[0274] Mix the following constituent materials to prepare Solution A-1.

[0275] Mixed solution of ethanol and 2,2,2-trifluoroethanol (8:2 by volume): 30 mL

[0276] Silane coupling agent a: 1,4-bis(trimethoxysilylethyl)benzene ((CH3O)3Si(CH2)2(C6H4)(CH2)2Si(OCH3)3): 2 mL

[0277] (Preparation of Solution A-2)

[0278] Mixed solution of ethanol and 2,2,2-trifluoroethanol (8:2 by volume): 19.5 mL

[0279] Pure water: 30 mL

[0280] Hydrochloric acid (36% by volume): 0.5 mL

[0281] (Formation of the first base layer)

[0282] While stirring the above-prepared Solution A-1 with a stirring rod, add 5 mL of Solution A-2 dropwise. After dropping, stir for about 1 hour, and then coat the mixed solution on the Cr-containing layer by spin coating under the condition that the thickness of the dried first base layer is 100 nm. The conditions for spin coating are 5000 rpm and 20 seconds. Then, dry the substrate at room temperature for 1 hour and bake it at 200 °C for 30 minutes.

[0283] (4) Formation of the third layer (second base layer)

[0284] (Preparation of coating liquid for forming the second base layer)

[0285] Mix the following constituent materials to prepare a coating solution for forming a second base layer.

[0286] A mixed solution of ethanol and 2,2,2-trifluoroethanol (volume ratio 8:2) 69 mL

[0287] Pure water 30 mL

[0288] Silane coupling agent c: 3-aminopropyltriethoxysilane ((C2H5O)3SiC3H6NH2)

[0289] KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd. 1 mL

[0290] (Formation of the second base layer)

[0291] Coat the coating solution for forming the second base layer (KBE-903 concentration: 1.0% by volume) prepared above on the first base layer of the stainless steel substrate by spin coating under the condition that the layer thickness of the dried second base layer is 20 nm. The spin coating condition is 20 seconds at 3000 rpm. Then, after drying the stainless steel substrate at room temperature for 1 hour, heat treatment is carried out for 1 hour under the conditions of 90 °C and 80% RH.

[0292] (5) Formation of the fourth layer (liquid-repellent layer)

[0293] (Preparation of the coating solution for forming the liquid-repellent layer)

[0294] Mix the following constituent materials to prepare a coating solution for forming the liquid-repellent layer.

[0295] A mixed solution of ethanol and 2,2,2-trifluoroethanol (volume ratio 8:2) 69.8 mL

[0296] Pure water 30 mL

[0297] Fluorine-containing coupling agent b: (2-perfluorooctyl)ethyltrimethoxysilane (CF3(CF2)7C2H4Si(OCH3)3) 0.2 mL

[0298] (Formation of the liquid-repellent layer)

[0299] Coat the coating solution for forming the liquid-repellent layer containing 0.2% by volume of the fluorine atom-containing coupling agent b prepared above on the second base layer formed above by spin coating under the condition that the layer thickness of the dried liquid-repellent layer becomes 10 nm. The spin coating condition is 20 seconds at 1000 rpm. Then, after drying the stainless steel substrate at room temperature for 1 hour, heat treatment is carried out for 1 hour under the conditions of 90 °C and 80% RH to produce the nozzle plate 1.

[0300] [Chemical formula 1]

[0301] Silane coupling agent a

[0302]

[0303] Coupling agent b containing fluorine

[0304]

[0305] Silane coupling agent c

[0306] (C2H5O)3SiC3H6NH2

[0307] (6) Measurement of Ar / Cr and Cr / Fe in the Cr-containing layer

[0308] Using XPS (X-ray Photoelectron Spectroscopy), Cr sputtering and plasma treatment were performed on the stainless steel substrate of the nozzle plate 1. For the sample formed to the Cr-containing layer, X-rays were irradiated on its surface, and the energy of the generated photoelectrons was measured, thereby analyzing the concentration (atm%) of metals (Cr, Fe) as structural elements of the sample, and the concentrations (atm%) of argon (Ar), oxygen (O), nitrogen (N), and carbon (C).

[0309] The measurement conditions are as described below.

[0310] · Analysis device: QUANTERA SXM manufactured by ULVAC-PHI

[0311] · X-ray source: Monochromatic Al-Kα

[0312] The Ar / Cr in the Cr-containing layer constituting the nozzle plate 1 measured by the above method is 0.02. For Cr / Fe, Cr is approximately 100 atm%, and almost no Fe is detected, so it is shown as "∞" in Table 1.

[0313] (7) Measurement of the content ratio (atm%) of trivalent Cr to the total Cr content in the Cr-containing layer

[0314] Using X-ray photoelectron spectroscopy, for the sample in which a Cr-containing layer was formed by performing Cr sputtering and plasma treatment on the substrate, the content ratio (atm%) of trivalent Cr to the total Cr content exemplified in Figure 7 was determined.

[0315] As a specific measurement device, QUANTERA SXM manufactured by ULVAC-PHI was used. The measurement sequence was that the X-ray anode used monochromatic Al-Kα and was measured at an output of 25W. It should be noted that the analysis method of detailed measurement data is as described above, and the description is omitted.

[0316] The content ratio of trivalent Cr in the Cr-containing layer constituting the nozzle plate 1 measured by the above method is 90 atm%.

[0317] [Fabrication of Nozzle Plate 2]

[0318] In the fabrication of the above nozzle plate 1, in the step of forming the Cr-containing layer, only the "etching based on the Ar-RIE plasma mode" in Step 2 is performed, and the "formation of the Cr layer by the sputtering method" in Step 1 is not performed. Except for this, the nozzle plate 2 is fabricated in the same way. The Ar / Cr of the Cr-containing layer of the nozzle plate 2 is 0.03, Cr / Fe is 1.2, and the content ratio of trivalent Cr to the total Cr content is 94 atm%.

[0319] [Fabrication of Nozzle Plate 3]

[0320] In the fabrication of the above nozzle plate 2, the "etching based on the Ar-RIE plasma mode" in Step 2 of the step of forming the Cr-containing layer is changed to a step of degreasing the surface with acetone and performing a treatment at 650 °C for 30 minutes in a nitrogen atmosphere, thereby fabricating the nozzle plate 3. The N / Cr of the Cr-containing layer of the nozzle plate 3 is 0.2 or more, and Cr / Fe and trivalent Cr cannot be measured.

[0321] [Fabrication of Nozzle Plate 4]

[0322] In the fabrication of the above nozzle plate 2, instead of the "etching based on the Ar-RIE plasma mode" in Step 2 of the step of forming the Cr-containing layer, it is changed to use O2 gas as the reaction gas and use Figure 6 the "etching based on the O2-PE plasma mode" of the described PE plasma mode. Except for this, the nozzle plate 4 is fabricated in the same way. The Ar / Cr of the Cr-containing layer of the nozzle plate 4 is 0, Cr / Fe is 1.0, and the content ratio of trivalent Cr to the total Cr content ratio is 35 atm%.

[0323] "Evaluation of Nozzle Plates"

[0324] For each of the above fabricated nozzle plates, the evaluation of ink resistance and adhesion durability is performed based on the following method.

[0325] [Evaluation of Ink Resistance]

[0326] (Formation of Nozzle Holes)

[0327] For the above fabricated nozzle plates 1 to 6, a laser processing machine is used to form a plurality of Figure 1 or Figure 2 nozzle holes with a diameter of 25 μm having the structure described.

[0328] (Preparation of Evaluation Actual Ink: Disperse Dye Ink)

[0329] <Preparation of Dispersion Liquid>

[0330]

[0331] The above mixture was dispersed for 5 hours at a rotation speed of 2,500 rpm using ceramic beads with a diameter of 0.5 mm and a sand mill manufactured by AIMEX Co., Ltd. The dispersion liquid was diluted with water / diethylene glycol = 1:4 so that the dye concentration was 5% to prepare Dispersion Liquid 1.

[0332] 〈Preparation of Actual Ink〉

[0333] Each composition was added to and stirred in the above Dispersion Liquid 1 to prepare an actual ink for evaluation (disperse dye ink).

[0334]

[0335] Ion-exchanged water was added to make it 100% by mass.

[0336] (Evaluation of Nozzle Plate)

[0337] The nozzle plate having each nozzle hole formed therein was immersed in the actual ink at 60°C for 30 days.

[0338] After the immersion treatment, it was washed and dried with pure water and then observed with a 100-fold magnifying glass. Figure 1 、 Figure 2 The presence or absence of peeling between the stainless steel substrate and the Cr-containing layer inside the nozzle hole shown in was evaluated for the adhesion resistance of the nozzle hole to the actual ink based on the following criteria.

[0339] ◎: No peeling was observed in all nozzles.

[0340] 〇: Extremely weak peeling was seen in less than 5% of the nozzles, but it was practically no problem.

[0341] △: Extremely weak peeling occurred in 5% or more and less than 10% of the nozzles, but it was practically no problem.

[0342] ×: There were nozzles with obvious peeling, which was a practical problem.

[0343] 〔Evaluation of Adhesion Durability (Wiping Resistance)〕

[0344] (Preparation of Black Ink)

[0345] Prepare black ink for evaluating the following structure.

[0346] 〈Preparation of Black Pigment Dispersion〉

[0347]

[0348] Mix the above components and disperse them using a horizontal bead mill filled with 0.3 mm zirconia beads at a volume ratio of 60% to obtain a black pigment dispersion. The average particle diameter is 125 nm.

[0349] <Preparation of Black Ink>

[0350]

[0351] (Wiping Test)

[0352] In a container containing the black ink prepared above at 25°C, fix each nozzle plate having a plurality of nozzle holes formed by the above method with a fixing tool so that the liquid-repellent layer is on top, and use an ethylene propylene diene rubber scraper to perform multiple wiping (brushing) operations on the surface of the liquid-repellent layer of the nozzle plate. Evaluate the adhesion durability based on the following criteria.

[0353] ◎: Even after 5000 or more wiping operations, no peeling of the liquid-repellent layer near the nozzles was observed for all nozzles.

[0354] ○: In wiping operations less than 5000 times, no peeling of the liquid-repellent layer near the nozzles was observed for all nozzles, but in wiping operations more than 5000 times, extremely weak peeling occurred for less than 5% of the nozzles.

[0355] △: In wiping operations less than 1000 times, no peeling of the liquid-repellent layer near the nozzles was observed for all nozzles, but in wiping operations in the range of 1000 - 5000 times, extremely weak peeling occurred for less than 5% of the nozzles.

[0356] ×: Nozzles with obvious peeling of the liquid-repellent layer that causes practical problems occurred during 1000 wiping operations.

[0357] Show the evaluation results obtained above in Table 1.

[0358]

[0359] As recorded in Table 1, it can be seen that: For the nozzle plate composed of the structure specified in the present invention, compared with the comparative example, even when exposed to the environment of the alkali ink component for a long time or when the surface is stressed, the base layer functions as a stress relaxation layer, and the bonding property between the respective constituent layers is high, and the ink resistance and adhesion durability are excellent. In addition, it can be seen that even after the nozzle plate of the present invention is immersed in the alkali ink for a long time, the adhesion between the stainless steel substrate inside the nozzle hole and the Cr-containing layer is also excellent.

[0360] Example 2

[0361] In the same way as Nozzles 1 - 3 of Example 1 Figure 4In the respective positions of components C, D1, D2, and E having a stainless-steel substrate, a structure of stainless-steel substrate / surface part / base layer (second layer·third layer) is formed, and the base layer having a resin layer is used as an adhesive layer. As a result of manufacturing components 1 to 3 and applying them, it was confirmed that the member having the structure defined in the present invention has excellent adhesion between members, ink resistance, and adhesion durability as compared with component 3 as a comparative example.

[0362] Industrial applicability

[0363] The inkjet head of the present invention has a member with excellent adhesion between members, ink resistance, and adhesion durability, and can be well used in inkjet printers using inks in various fields.

[0364] Symbol description

[0365] 1, 210 Nozzle plate

[0366] 2 Stainless-steel substrate

[0367] 3 Surface part

[0368] 4 Resin layer

[0369] 5 Liquid-repellent layer

[0370] 5A First base layer

[0371] 5B Second base layer

[0372] 6 Liquid-repellent layer

[0373] 10, 100 Inkjet head

[0374] 11 Connection part

[0375] 12 Nozzle chip

[0376] 13 Holding part

[0377] 15 Common ink chamber

[0378] 21 Reaction chamber

[0379] 22 High-frequency power supply

[0380] 23 Capacitor

[0381] 24 Planar electrode (power supply electrode)

[0382] 25 Opposing electrode (ground electrode)

[0383] 26 Ground

[0384] 27 Gas inlet

[0385] 28 Gas outlet

[0386] 30 Nozzle plate substrate

[0387] 31 Discharge space

[0388] 32, 33 Power supply wire

[0389] 56 Housing

[0390] 57 Cover receiving plate

[0391] 59 Cover component

[0392] 61 Nozzle plate

[0393] 62 Cover receiving plate mounting part

[0394] 68 Mounting hole

[0395] 71 Nozzle opening

[0396] 81a First connector

[0397] 81b Second connector

[0398] 82 Third connector

[0399] 220 Intermediate substrate

[0400] 230 Actuator substrate

[0401] 240 Protection substrate

[0402] 221 Communication hole

[0403] 20A RIE plasma processing apparatus

[0404] 20B PE plasma processing apparatus

[0405] In Ink

[0406] D Discharge

[0407] G Reaction gas

[0408] N Nozzle

[0409] P Pump

Claims

1. An inkjet head, characterized in that, It is composed of components with a stainless-steel substrate, and has a resin layer on the stainless-steel substrate, wherein the resin layer is a base layer and a liquid-repellent layer constituting a nozzle plate, the surface or side surface part of the resin layer is in contact with the ink, the ratio of the concentration of Ar to Cr in the surface part of the stainless-steel substrate, i.e., the value of Ar / Cr, is 0.01 or more, and the concentration unit is atm%, the base layer is a layer containing a silane coupling agent, and has a first base layer and a second base layer in sequence from the stainless-steel substrate side. The silane coupling agent contained in the first base layer has reactive functional groups at both ends and contains a hydrocarbon chain and a benzene ring in the middle part. The silane coupling agent contained in the second base layer is an oxide composed mainly of carbon, silicon and oxygen.

2. The inkjet head according to claim 1, characterized in that, The content rate of trivalent Cr relative to the total Cr content in the surface part of the stainless-steel substrate is 50 atm% or more.

3. The inkjet head according to claim 1 or claim 2, characterized in that, For the concentration ratio of the constituent elements in the surface part of the stainless-steel substrate, the ratio of the concentration of Cr to Fe, i.e., the value of Cr / Fe, is 0.8 or more, and the concentration unit is atm%.

4. The inkjet head according to any one of claims 1 to 3, characterized in that, A Cr-containing layer is provided on the surface part of the stainless-steel substrate, and the layer thickness of the Cr-containing layer is in the range of 5 to 50 nm.

5. The inkjet head according to any one of claims 1 to 4, wherein The component with the stainless-steel substrate is a component constituting a nozzle plate, an ink flow path, an ink chamber or an exterior part in contact with the ink.

6. The inkjet head according to any one of claims 1 to 5, characterized in that, The liquid-repellent layer is a layer formed using a coupling agent having fluorine F.

7. The inkjet head according to any one of claims 1 to 6, characterized in that, The ink contains at least a colorant and 1% by mass or more of water.

8. The inkjet head according to any one of claims 1 to 7, characterized in that, The ink is an alkaline ink.

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