Protective film, method for manufacturing a protective film, inkjet head, method for manufacturing an inkjet head, and inkjet recording apparatus

Abstract

To provide a protective film with uniform thickness and improved heat resistance. [Solution] The protective film comprises, in order, a first organic layer, an inorganic layer, and a second organic layer. The first organic layer and the second organic layer contain polyparaxylylene or a derivative thereof having a structure represented by general formula (1), or a derivative of polyparaxylylene having a structure represented by general formula (2). At least one of the first organic layer and the second organic layer contains a derivative of polyparaxylylene having a structure represented by general formula (2).

Description

[Technical Field]

[0001] The present invention relates to a protective film, a method for manufacturing the protective film, an inkjet head, a method for manufacturing the inkjet head, and an inkjet recording apparatus. [Background Art]

[0002] By providing a protective film including an inorganic thin film and an organic thin film on a surface that comes into contact with ink, corrosion of a base material and other members can be suppressed (Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] International Publication No. 2022 / 244542 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] For example, a head chip of an inkjet head is manufactured by joining the respective included members with an adhesive. In recent years, from the viewpoint of extending the service life of products, adhesives having high durability against solvents contained in ink are used. Such adhesives generally have a high curing temperature, and each member is exposed to high temperature during joining. Therefore, further improvement in heat resistance is required for the protective film provided on the surface of a flow path, that is, the surface that comes into contact with ink.

[0005] In addition, the head chip of an inkjet head partially has a concavo-convex structure or a plurality of different materials are exposed on the surface of the flow path, so it is difficult to form a protective film with a uniform thickness, and it is difficult to obtain a sufficient protective function in a portion where the protective film is thin.

[0006] The problem to be solved by the present invention is to provide a protective film or the like that has a uniform thickness and improved heat resistance. [Means for Solving the Problem]

[0007] The inventors investigated the causes of the above problems in order to solve them. The protective film comprises a first organic layer, an inorganic layer, and a second organic layer in that order, and the first and second organic layers contain a predetermined polyparaxylylene or a derivative thereof. This led to the discovery that a protective film with uniform thickness and improved heat resistance can be provided, resulting in the present invention. In other words, the above problems according to the present invention are solved by the following means.

[0008] 1. It has, in order, a first organic layer, an inorganic layer, and a second organic layer, The first organic layer and the second organic layer contain polyparaxylylene or a derivative thereof having a structure represented by the following general formula (1), or a derivative of polyparaxylylene having a structure represented by the following general formula (2). A protective film in which at least one of the first organic layer and the second organic layer contains a derivative of polyparaxylylene having a structure represented by the following general formula (2).

[0009] [ka]

[0010] In general formula (1), each of the a X1 atoms independently represents an alkyl group having 1 to 5 carbon atoms, or a halogen atom. a represents an integer from 0 to 4. n1 represents the number of polymerization units.

[0011] [ka]

[0012] In general formula (2), each of the b X2 atoms independently represents an alkyl group having 1 to 5 carbon atoms, or a halogen atom. b is an integer from 0 to 4. n2 represents the number of polymerization units. Each of the c X3 atoms independently represents an alkyl group having 1 to 5 carbon atoms. c is an integer from 0 to 3. d is an integer from 1 to 4. n3 represents the number of polymerization units.

[0013] 2. The protective film according to Item 1, wherein the second organic layer contains a polyparaxylylene derivative having a structure represented by the general formula (2).

[0014] 3. The protective film according to Item 1, wherein both the first organic layer and the second organic layer contain a polyparaxylylene derivative having a structure represented by the general formula (2).

[0015] 4. The protective film according to Item 1, wherein the thickness of the first organic layer is within a range of 0.1 to 10 µm.

[0016] 5. The protective film according to Item 1, wherein the thickness of the second organic layer is within a range of 0.1 to 10 µm.

[0017] 6. The protective film according to Item 1, wherein the thickness of the inorganic layer is within a range of 10 to 500 nm.

[0018] 7. The protective film according to Item 1, wherein the inorganic layer includes a film containing an oxide of aluminum, silicon, titanium, hafnium, or tantalum.

[0019] 8. A method for producing a protective film for producing the protective film according to any one of Items 1 to 7, comprising: a first organic layer forming step of forming the first organic layer; an inorganic layer forming step of forming the inorganic layer on the formed first organic layer; a second organic layer forming step of forming the second organic layer on the formed inorganic layer; and in the inorganic layer forming step, the inorganic layer is formed using a chemical vapor deposition method, a sputtering method, or an atomic layer deposition method.

[0020] 9. Having a flow path through which ink flows, having the protective film according to any one of Items 1 to 7 on a surface of the flow path, an inkjet head, wherein the first organic layer is located on the surface side of the flow path, and the second organic layer is located on the side that comes into contact with the ink.

[0021] 10. The inkjet head according to Item 9, wherein a surface of the flow channel has an uneven structure.

[0022] 11. The inkjet head according to Item 9, wherein an adhesive and a plurality of substrates of different materials are exposed on a surface of the flow channel.

[0023] 12. The inkjet head according to Item 9, comprising an actuator, a flow channel substrate, and a nozzle substrate, wherein the actuator, the flow channel substrate, and the nozzle substrate are bonded together with an adhesive.

[0024] 13. A method of manufacturing an inkjet head for manufacturing the inkjet head according to Item 12, wherein the protective film is exposed to an environment of 80°C or higher.

[0025] 14. An inkjet recording apparatus comprising the inkjet head according to Item 12. Effects of the Invention

[0026] According to the present invention, the protective film can have a uniform thickness and improved heat resistance. As a result, the protective film can protect the base material over a long period of time.

[0027] The mechanism by which the effects of the present invention are exhibited or acts is inferred as follows.

[0028] Compared to inorganic films, an appropriate material can be selected for an organic film to make it less susceptible to the influence of the liquidity (pH value) of a liquid in contact therewith. In addition, inorganic films have higher water resistance than organic films. Therefore, by including both an organic film and an inorganic film in the protective film, durability against a liquid in contact therewith can be enhanced.

[0029] Conventional protective films, particularly organic films within protective films, are prone to cracks and other defects within the protective film due to the breakdown of polymer molecular bonds caused by reactive oxygen species generated in high-temperature environments. Liquids can then penetrate the substrate through these cracks and other defects, leading to corrosion of the substrate and other components.

[0030] In this embodiment, a derivative of polyparaxylylene (PPX-NH2) with an amino group introduced into it is used as the polymer contained in the protective film. Although the mechanism is not clear, PPX-NH2 is less prone to cracking and other defects even in high-temperature environments and has high heat resistance. Therefore, it can protect the substrate over a long period of time.

[0031] Conventional protective films, particularly inorganic films within protective films, struggle to form uniformly thick, even films if the underlying layer on which the film is deposited is non-uniform. Specifically, if the surface (film-forming surface) of the underlying layer is not flat but has an uneven structure, it is difficult to form an inorganic film of uniform thickness along that uneven structure. Furthermore, if multiple different materials are exposed on the surface of the underlying layer, it is difficult to form an inorganic film of uniform thickness.

[0032] In this embodiment, the protective film has at least three layers, with a first organic layer provided between the substrate and the inorganic layer. The first organic layer easily forms a film of uniform thickness even if the surface of the substrate is uneven, and the inorganic layer easily forms a film of uniform thickness on the first organic layer. In other words, by providing the first organic layer, it is easy to form an inorganic layer of uniform thickness. As a result, a protective film can be formed evenly on the substrate, and it is believed that the substrate can be protected for a long period of time. [Brief explanation of the drawing]

[0033] [Figure 1] This is a perspective view showing an example of an inkjet print head. [Figure 2] This is a cross-sectional view of an inkjet print head. [Figure 3] This is a partial cross-sectional view of an inkjet print head. [Figure 4] This is a cross-sectional view along the line IV-IV in Figure 3. [Figure 5]This is a schematic cross-sectional view showing an example of a laminate. [Figure 6] This is a schematic cross-sectional view showing an example of a laminate. [Figure 7] This is a flowchart illustrating the manufacturing method of an inkjet print head. [Figure 8] This is a flowchart explaining the actuator manufacturing process. [Figure 9] This is a flowchart explaining the protection process. [Figure 10] This is a schematic diagram showing the general configuration of an inkjet recording device. [Figure 11] This is a schematic diagram showing the line head as viewed from the conveyor belt side. [Modes for carrying out the invention]

[0034] The protective film of the present invention comprises, in order, a first organic layer, an inorganic layer, and a second organic layer. The first organic layer and the second organic layer contain polyparaxylylene or a derivative thereof having the structure represented by the general formula (1) above, or a derivative of polyparaxylylene having the structure represented by the general formula (2) above. At least one of the first organic layer and the second organic layer contains a derivative of polyparaxylylene having the structure represented by the general formula (2) above. The protective film of the present invention is characterized by the above. This feature is a technical feature common to or corresponding to the following embodiments.

[0035] In this embodiment, it is preferable that the second organic layer contains a polyparaxylylene derivative having the structure represented by the general formula (2) above. As a result, the second organic layer on the side in contact with the liquid has heat resistance, so the effects of the liquid are less likely to extend to the inorganic layer and the first organic layer on the substrate side, and the substrate can be protected over a long period of time.

[0036] In this embodiment, it is preferable that both the first organic layer and the second organic layer contain a polyparaxylylene derivative having the structure represented by the general formula (2) described above. As a result, both organic layers have heat resistance, and the substrate can be protected over a long period of time.

[0037] In this embodiment, the thickness of the first organic layer is preferably in the range of 0.1 to 10 μm. This allows it to fully function as a protective film.

[0038] In this embodiment, the thickness of the second organic layer is preferably in the range of 0.1 to 10 μm. This allows it to fully perform its function as a protective film.

[0039] In this embodiment, the thickness of the inorganic layer is preferably in the range of 10 to 500 nm. This allows the origin of any minute defects that occur in the inorganic layer to be filled in, and also improves durability.

[0040] In this embodiment, the inorganic layer preferably contains a film containing an oxide of aluminum, silicon, titanium, hafnium, or tantalum. This allows for the formation of a dense film.

[0041] The present invention provides a method for manufacturing a protective film, comprising: a first organic layer formation step of forming a first organic layer; an inorganic layer formation step of forming an inorganic layer on the formed first organic layer; and a second organic layer formation step of forming a second organic layer on the formed inorganic layer. In the inorganic layer formation step, the inorganic layer is formed using chemical vapor deposition, sputtering, or atomic layer deposition.

[0042] The inkjet head of the present invention has a channel through which ink flows. The surface of the channel has the protective film described above. The first organic layer is located on the surface side of the channel, and the second organic layer is located on the side that comes into contact with the ink. This extends the lifespan of the inkjet head.

[0043] In this embodiment, the surface of the flow channel may have an uneven structure. The protective film can be formed with a uniform thickness even on surfaces with an uneven structure, thereby extending the lifespan of the inkjet head.

[0044] In this embodiment, the surface of the flow path may have an adhesive and substrates made of multiple different materials exposed. The protective film can be formed with a uniform thickness even on the surface where the adhesive and substrates made of multiple different materials are exposed, thereby extending the lifespan of the inkjet head.

[0045] In this embodiment, the system comprises an actuator, a flow channel substrate, and a nozzle substrate, and it is preferable that the actuator, flow channel substrate, and nozzle substrate are joined together with an adhesive. Since the protective film has heat resistance, it is less likely to deteriorate even when exposed to high temperatures during joining, thereby extending the lifespan of the inkjet head.

[0046] In the inkjet head manufacturing method of the present invention, the protective film may be exposed to an environment of 80°C or higher. Even in this case, the lifespan of the inkjet head is sufficiently long.

[0047] The inkjet recording device of the present invention is equipped with the above-described inkjet head. This makes it possible to extend the lifespan of the inkjet recording device.

[0048] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the disclosed embodiments. That is, although the following description will focus on the case in which a protective film is provided in the flow path of an inkjet head, the use of the protective film is not limited to this.

[0049] [Inkjet head] Figure 1 is a perspective view showing an example of the inkjet head 1 of this embodiment. Figure 2 is a partial cross-sectional view of the inkjet head 1. When recording to a recording medium, the bottom surface of the inkjet head and the recording surface of the recording medium are positioned opposite each other. Specifically, the recording medium is positioned so that its recording surface is located below the inkjet head and perpendicular to the direction in which the ink is ejected. Inkjet recording is performed as the recording medium is transported.

[0050] For convenience, in the following explanation, the direction in which ink is ejected from the inkjet head will be considered downwards, and the opposite direction will be considered upwards. Furthermore, the direction in which the recording medium is transported will be considered the front-to-back direction, and the direction perpendicular to the direction in which the recording medium is transported on the recording surface will be considered the left-to-right direction.

[0051] The inkjet head 1 comprises an actuator 30, a manifold (not shown), a flow path substrate 40, and a nozzle substrate 50, which are housed in a housing 6. A flexible substrate, a drive circuit board, etc. (not shown) are located above these, and these are covered by a cover member 7 attached to the housing 6.

[0052] The housing 6 is formed by die-casting using, for example, aluminum as the material. The housing 6 has a long shape, for example, in the left-right direction. The bottom surface of the housing 6 has an opening so that the nozzle substrate 50 is exposed to the outside. The housing 6 has mounting holes 68 at both ends in the left-right direction for attaching the housing 6 to the printer body.

[0053] In the example shown in Figure 2, the actuator 30 is of the bend mode type. The nozzle substrate 50 has a nozzle 51 for ejecting ink to the outside of the inkjet head 1. The actuator 30, the flow channel substrate 40, and the nozzle substrate 50 are each joined together via an adhesive layer 2.

[0054] In this embodiment, the "flow channel substrate" refers to a substrate that forms a flow channel through which ink flows, and is located between the actuator 30 and the nozzle substrate 50. The flow channel substrate 40 is provided with a supply channel 21, a supply-side communication channel 23, and a nozzle-side communication channel 24. The supply-side communication channel 23 extends from the top of the supply channel 21 and is connected to the pressure chamber 22. The nozzle-side communication channel 24 penetrates the flow channel substrate 40 to connect the pressure chamber 22 and the nozzle 51 of the nozzle substrate 50.

[0055] The material of the flow channel substrate 40 is not particularly limited, but examples include glass, ceramic, silicon, plastic, stainless steel, etc.

[0056] The nozzle substrate 50 has a nozzle 51 that penetrates the nozzle substrate 50 at a position corresponding to the nozzle-side communication channel 24 extending from the lower part of the pressure chamber 22. The nozzle 51 has a shape in which the diameter gradually decreases as it extends downward, and the diameter is uniform near the outlet. The material of the nozzle substrate 50 is not particularly limited, but examples include silicon, polyimide, stainless steel, etc.

[0057] The actuator 30 has a pressure chamber layer 31 that forms a pressure chamber 22, and a diaphragm 32, an insulating layer 33, a piezoelectric layer 34, and an electrode layer 35 are laminated on top of the pressure chamber layer 31. The diaphragm 32, insulating layer 33, piezoelectric layer 34, and electrode layer 35 can be formed by a vacuum deposition method such as sputtering. These layers may also be formed by other deposition methods such as coating.

[0058] The pressure chamber layer 31 can be formed by a thick film formation method such as plating or by an etching method for a metal plate. The pressure chamber 22 is formed when the flow channel substrate 40 is joined to the lower surface of the pressure chamber layer 31. Examples of known metal materials for the pressure chamber layer 31 include nickel (Ni).

[0059] The diaphragm 32 contains a conductive metallic material and also serves as the lower electrode (common electrode) of the piezoelectric layer 34. Examples of the metallic material for the diaphragm 32 include known metallic materials such as nickel (Ni).

[0060] The insulating layer 33 insulates the diaphragm 32 from the piezoelectric layer 34. In other words, the insulating layer 33 shields the application of voltage to the piezoelectric layer 34 outside the piezoelectric functional region R1.

[0061] The piezoelectric layer 34 preferably contains a perovskite-type compound. Examples of perovskite-type compounds include barium titanate (BaTiO3) and lead zirconate titanate (PZT: Pb(Zr·Ti)O3), with PZT being the main component. The molar ratio of Zr to Ti in PZT is preferably in the range of Zr / Ti = 30 / 70 to 70 / 30. Here, "main component" means being present in an amount of 85% or more by mass relative to the total mass of the piezoelectric material.

[0062] To improve the performance of the piezoelectric material, donor ions may be added to the PZT. Examples of donor ions include metal ions such as lanthanum (La), niobium (Nb), tantalum (Ta), tungsten (W), aluminum (Al), and strontium (Sr). In particular, it is preferable that the donor ion be one or more metal ions selected from the group including La, Nb, Ta, and W. Furthermore, it is preferable that the thickness of the piezoelectric layer 34 be about a few μm.

[0063] The electrode layer 35 contains a conductive material. For example, the electrode layer 35 contains titanium, which is a precious metal. The thickness of the electrode layer 35 is approximately 0.2 μm.

[0064] When a voltage is applied to the electrode layer 35, the piezoelectric layer 34 deforms downward in the piezoelectric functional region R1, and consequently, the diaphragm 32 deforms. When the diaphragm 32 deforms downward in the piezoelectric functional region R1, the volume of the pressure chamber 22 decreases, and the pressure of the ink 60 filled in the pressure chamber 22 increases. Conversely, when the diaphragm 32 deforms upward in the piezoelectric functional region R1, the volume of the pressure chamber 22 increases, and the pressure of the ink 60 filled in the pressure chamber 22 decreases. By varying the pressure of the ink 60 in a predetermined sequence, for example, by reducing the pressure and then increasing it, droplets 61 of ink 60 are ejected from the nozzle 51, which communicates with the pressure chamber 22 via the nozzle-side communication channel 24.

[0065] The pressure chamber layer 31, diaphragm 32, insulating layer 33, piezoelectric layer 34, and electrode layer 35 do not necessarily have to be single layers, but may each be made up of multiple layers. Furthermore, other layers may be positioned between each of the layers.

[0066] The thickness of the adhesive layer 2 is preferably in the range of 0.1 to 5 μm.

[0067] The adhesive used to form the adhesive layer 2 is not particularly limited as long as it is an adhesive that can bond the actuator 30, the flow channel substrate 40, and the nozzle substrate 50, respectively. Examples of adhesives include room-temperature curing adhesives that cure at room temperature, thermosetting adhesives that cure by accelerating polymerization through heating, and active energy ray curing adhesives that cure by accelerating polymerization through irradiation with active energy rays such as ultraviolet light.

[0068] In particular, a thermosetting adhesive is preferred. Thermosetting adhesives generally have strong resistance to solvents contained in inks and do not deteriorate easily even when in contact with ink. Furthermore, when a thermosetting adhesive is heated to a predetermined temperature for curing after bonding, the viscosity of the adhesive temporarily decreases, making it more fluid and easier to obtain a uniform thickness of the resulting adhesive layer. Examples of thermosetting adhesives include epoxy adhesives containing epoxy resin and fluororesin adhesives containing fluororesin. In addition, a conductive adhesive may be used from the viewpoint of good electrical connection. Examples of conductive adhesives include adhesives in which conductive particles are dispersed.

[0069] In this embodiment, the "surface of the flow path" refers to the surface of the actuator 30, the flow path substrate 40, and the nozzle substrate 50 that comes into contact with the ink. Specifically, it refers to the outer surface of the supply flow path 21, the pressure chamber 22, the supply-side communication flow path 23, the nozzle-side communication flow path 24, and the nozzle 51. As shown in Figure 2, the width of the flow path through which the ink flows is not uniform, and the surface of the flow path has numerous irregularities such as corners, edges, and steps. The inkjet head 1 is provided with a protective film 4 on the surface of this flow path. In Figure 2, the protective film 4 is provided on only a portion of the surface of the flow path, but the protective film 4 may be provided on the entire surface of the flow path. The actuator 30 and the flow path substrate 40 each have minute irregularities, corners, edges, etc., on the surface of their flow paths even individually. Therefore, as shown in Figure 2, the effects of the present invention can be fully obtained even if the protective film 4 is provided only on the surface of the flow path of the actuator 30 alone. Alternatively, the protective film 4 may be provided from the surface of the flow path of the actuator 30 to the surface of the flow path of the flow path substrate 40. In this case, the joint between the actuator 30 and the flow path substrate 40 is a joint where multiple different materials are joined via the adhesive layer 2, and the effects of the present invention can be obtained more significantly.

[0070] Figure 3 is a partial cross-sectional view of the inkjet head 1. In the example shown in Figure 3, the actuator 30 is of the shear mode type. The actuator 30 and the nozzle substrate 50 are joined via an adhesive layer 2. Although not shown in Figure 3, a flow channel substrate 40 may be provided between the actuator 30 and the nozzle substrate 50.

[0071] The actuator 30 has a pressure chamber layer 31 that forms a drive channel (pressure chamber) 11 and a dummy channel 12. The partition wall between the drive channel 11 and the dummy channel 12 is a drive wall 13 containing a piezoelectric material. Preferably, the piezoelectric material contains the same compound as that used in the bend-mode type.

[0072] The drive channel 11 and dummy channel 12 penetrate the pressure chamber layer 31, and the drive channel 11 is connected to the nozzle 51 of the nozzle substrate 50. The nozzle substrate 50 has a nozzle 51 at a position corresponding to the drive channel 11. The nozzle substrate 50 does not have a nozzle 51 at a position corresponding to the dummy channel 12, and therefore the lower opening of the dummy channel 12 is blocked by the nozzle substrate 50. During ink ejection, ink flows through the drive channel 11 in the direction of the arrow, but no ink flows through the dummy channel 12. The dummy channel 12 is usually filled with a gas such as air.

[0073] Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 3. As shown in Figure 4, the drive electrodes 14 are located on the surfaces of the four walls facing into the drive channel 11 and the dummy channel 12. The actuator 30 is provided with protective films 4 on the four walls of the drive electrodes 14 that come into contact with the ink. In Figures 3 and 4, the drive electrodes 14 in the drive channel 11 are provided with protective films 4 on the four walls that come into contact with the ink, but the drive electrodes 14 in the dummy channel 12 may also be provided with protective films 4. By providing protective films 4 in the dummy channel 12, the drive electrodes 14 can be protected from moisture contained in gases such as air.

[0074] On the upper surface of the pressure chamber layer 31, connecting electrodes 15 are positioned to correspond one-to-one with the drive channels 11 and dummy channels 12. One end of each connecting electrode 15 is electrically connected to the drive electrode 14 in the corresponding drive channel 11 or dummy channel 12.

[0075] The actuator 30 shown in Figures 3 and 4 is an independently driven actuator in which drive channels 11 and dummy channels 12 are alternately positioned in each channel row of the pressure chamber layer 31. The actuator 30 deforms the drive wall 13 by shearing it by applying a drive signal of a predetermined voltage to the drive electrode 14. As a result, the pressure in the ink supplied into the drive channel 11 changes, and ink droplets are ejected from the nozzle 51 of the nozzle substrate 50.

[0076] The driving electrode 14 and the connecting electrode 15 contain a conductive material. Examples of conductive materials include platinum (Pt), gold (Au), copper (Cu), palladium (Pd), ruthenium (Ru), titanium (Ti), nickel (Ni), aluminum (Al), chromium (Cr), tungsten (W), and iridium (Ir). These may be included individually or in combination of two or more. The conductive material may be a mixture of metals or an alloy. In that case, it may be a mixture or alloy of at least one of the above metals with other metals.

[0077] The thickness of the adhesive layer 2 is preferably in the range of 0.1 to 5 μm. The adhesive used to form the adhesive layer 2 is not particularly limited, and the same adhesive as that used for the bend-mode type can be used.

[0078] (protective film) Figures 5 and 6 are schematic cross-sectional views showing an example of a laminate 70. The laminate 70 includes a protective film 4 on a substrate 71. The protective film 4 primarily protects the substrate 71 from ink, but may also protect the substrate 71 from other elements such as the outside air. The protective film 4 comprises at least a first organic layer 41, an inorganic layer 42, and a second organic layer 43 from the substrate 71 side. The protective film 4 may have layers other than the first organic layer 41, the inorganic layer 42, and the second organic layer 43. For example, as shown in Figure 6, there may be a fourth layer 44 between the substrate 71 and the first organic layer 41, or a fifth layer 45 on the surface side of the second organic layer. Although not shown, there may also be other layers between the first organic layer, the inorganic layer, and the second organic layer.

[0079] As described above, in bend mode, protective films 4 are provided on the pressure chamber layer 31 and on the diaphragm 32. In this case, the pressure chamber layer 31, diaphragm 32, flow path substrate 40, and nozzle substrate 50 correspond to the base material 71 in the laminate 70. In shear mode, a drive electrode 14 is provided on the pressure chamber layer 31, and a protective film 4 is further provided on the drive electrode 14. In this case, the drive electrode 14 corresponds to the base material 71 in the laminate 70.

[0080] In the manufacturing of an inkjet head, it is preferable that the actuator 30, the flow channel substrate 40, and the nozzle substrate 50 are joined together with an adhesive after they have been manufactured. This allows for the use of suitable materials for each part and simplifies the manufacturing process. The actuator 30, the flow channel substrate 40, and the nozzle substrate 50 may be joined together with an adhesive after a protective film 4 is formed on each of them, or the protective film 4 may be formed on the surface of the formed flow channels after they have been joined with an adhesive.

[0081] In the method of bonding with an adhesive after forming the protective film 4, the protective film 4 is exposed to a high-temperature environment (the curing temperature of the adhesive). Therefore, the protective film 4 needs to have heat resistance so that microcracks do not occur even when exposed to a high-temperature environment of, for example, around 80°C. In the method of forming the protective film 4 after bonding with an adhesive, the protective film 4 is formed on a surface where the adhesive and substrates of multiple different materials are exposed. Therefore, it is necessary to form a protective film 4 of uniform thickness on the surface of a channel made of different materials that is not partially planar.

[0082] Furthermore, when using an inkjet head, the ink may be heated to a relatively high temperature to improve ejection performance, in which case the protective film 4 is exposed to a high-temperature environment. Also, when attaching the chip obtained by joining the actuator 30, the flow path substrate 40, and the nozzle substrate 50 into the housing 6, adhesive may be used. In this case as well, the protective film 4 is exposed to a high-temperature environment. Therefore, regardless of the method of manufacturing the inkjet head, it is preferable that the protective film 4 has heat resistance so that microcracks and the like do not occur even when exposed to a high-temperature environment of, for example, about 80°C.

[0083] The overall thickness of the protective film 4 is not particularly limited, but is preferably in the range of 0.2 to 20 μm, more preferably in the range of 0.5 to 15 μm, and even more preferably in the range of 1 to 10 μm. Having a certain thickness allows the protective film to function fully. Also, not being too thick does not hinder the deformation of the diaphragm 32 in the bend mode or the deformation of the drive wall 13 in the shear mode. The thickness can be controlled by adjusting the film formation conditions and the amount of raw material added in each layer.

[0084] The organic and inorganic layers that make up the protective film 4 will be described in order below.

[0085] (1)Organic layer The first organic layer and the second organic layer will be explained together below. The organic layer contains polyparaxylylene or a derivative thereof having a structure represented by the following general formula (1), or a derivative of polyparaxylylene having a structure represented by the following general formula (2). At least one of the first organic layer and the second organic layer contains a derivative of polyparaxylylene having a structure represented by the following general formula (2). In this specification, polyparaxylylene or a derivative thereof having a structure represented by the following general formula (1) is also referred to as "PPX," and a derivative of polyparaxylylene having a structure represented by the following general formula (2) is also referred to as "PPX-NH2." In this embodiment, "PPX" does not include "PPX-NH2."

[0086] [ka]

[0087] In general formula (1), each of the a X1 atoms independently represents an alkyl group having 1 to 5 carbon atoms, or a halogen atom. a represents an integer from 0 to 4. n1 represents the number of polymerization units.

[0088] Alkyl groups may be linear or branched. Examples of C1-C5 alkyl groups include methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, secondary butyl, tertiary butyl, isopentyl, neopentyl, and tertiary pentyl groups. Examples of halogen atoms include fluorine, chlorine, and bromine.

[0089] In this embodiment, PPX is synthesized using 99 parts by mass or more of a paraxylylene compound that does not have an amino group, when the total amount of raw materials is 100 parts by mass.

[0090] A specific example of PPX is shown. n1 represents the polymerization number.

[0091] [ka]

[0092] [ka]

[0093] In general formula (2), each of the b X2 atoms independently represents an alkyl group having 1 to 5 carbon atoms, or a halogen atom. b is an integer from 0 to 4. n2 represents the number of polymerization units. Each of the c X3 atoms independently represents an alkyl group having 1 to 5 carbon atoms. c is an integer from 0 to 3. d is an integer from 1 to 4. n3 represents the number of polymerization units.

[0094] Alkyl groups may be linear or branched. Examples of C1-C5 alkyl groups include methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, secondary butyl, tertiary butyl, isopentyl, neopentyl, and tertiary pentyl groups. Examples of halogen atoms include fluorine, chlorine, and bromine.

[0095] The arrangement of the repeating structures is not particularly limited. PPX-NH2 may be a random copolymer, an alternating copolymer, a block copolymer, or a Kraft copolymer.

[0096] In this embodiment, PPX-NH2 is synthesized using 1 part by mass or more of a paraxylylene compound having an amino group, when the total raw materials are 100 parts by mass. For example, in a certain polymer, if the amount of paraxylylene compound without an amino group is more than 99 parts by mass and the amount of paraxylylene compound having an amino group is less than 1 part by mass, then the polymer is not considered to be PPX-NH2 and is considered to be PPX.

[0097] In PPX-NH2, when the total raw materials are 100 parts by mass, the amount of paraxylylene compound having an amino group used is preferably in the range of 1 to 20 parts by mass, and more preferably in the range of 2 to 10 parts by mass. By synthesizing in this ratio, the resulting film has good heat resistance. In other words, in terms of polymerization number, n2 / n3 is preferably in the range of 80 / 20 to 99 / 1, and more preferably in the range of 90 / 10 to 98 / 2.

[0098] Specific examples of PPX-NH2 are shown. n21, n22, and n3 represent the polymerization number. Note that in the repeating structure without an amino group, the specific examples show both a structure in which the hydrogen atoms of the benzene ring are substituted with chlorine atoms and a structure in which the hydrogen atoms are not substituted, but the structure in which the hydrogen atoms of the benzene ring are not substituted is not necessarily required.

[0099] [ka]

[0100] The organic layer may contain any resin or other material in addition to PPX or PPX-NH2.

[0101] Thin films containing PPX can be formed by chemical vapor deposition (CVD), also known as CVD, using polyparaxylylene or its derivative dimer (solid) as the deposition source. In chemical vapor deposition, when the dimer is heated under vacuum, it sublimes into a dimer gas. This gas decomposes thermally, causing the dimer to cleave and become monomers. In a deposition chamber at room temperature, this monomer gas polymerizes on all surfaces, forming a transparent thin film. Chemical vapor deposition makes it easy to form a uniform thin film without unevenness because the monomer gas can penetrate and polymerize even in narrow areas.

[0102] Specifically, a thin film is formed according to the following chemical reaction equation. Formula (I) below shows the chemical structure of dimer (I) of paraxylylene or its derivative. Hereinafter, paraxylylene or its derivative will also be referred to as "paraxylylene compound (A)".

[0103] The following formula (II) shows the diradical of the stable paraxylylene compound (A) generated by sublimation and thermal decomposition of the dimer (I), and the chemical structure of the paraxylylene compound (A). Formula (II) shows the state in which the diradical of the paraxylylene compound (A) and the paraxylylene compound (A) coexist reversibly.

[0104] Formula (III) below shows the chemical structure of polymer (III) of paraxylylene compound (A), which is obtained by adsorption of the diradicals of paraxylylene compound (A) onto a substrate and polymerization. Polymer (III) is formed as a film on the substrate.

[0105] In the CVD method, diradicals of stable paraxylylene compound (A) are generated by sublimation and thermal decomposition of dimer (I). The diradicals of paraxylylene compound (A) are preferable because they have excellent penetration into fine structures and penetrate sufficiently and uniformly deep into the microstructure of the substrate.

[0106] [ka]

[0107] In the above formulas (I), (II), and (III), X1 and a are the same as X1 and a in the above general formula (1).

[0108] Thin films containing PPX-NH2 can be fabricated using the same procedure as thin films containing PPX.

[0109] The organic layer may be oxidized on its surface, i.e., the surface facing the channel surface. Methods of oxidation include laser irradiation, UV / ozone treatment, and plasma irradiation. Among these, plasma irradiation is preferred. Oxidation introduces hydrophilic groups such as carboxyl groups and hydroxyl groups to the surface of the first organic layer, uniformly increasing the critical surface tension of the film. Furthermore, minute irregularities can be introduced to the surface of the first organic layer. This improves the adhesion between the first organic layer and the inorganic layer, thereby improving the durability of the substrate and the yield during manufacturing. Note that these irregularities are extremely minute and do not significantly affect the uniform layer formation of the inorganic layer.

[0110] From the viewpoint of improving heat resistance, it is preferable that both the first organic layer and the second organic layer contain PPX-NH2. However, from the viewpoint of improving adhesion between the substrate and the protective layer, the first organic layer may be PPX and the second organic layer may be PPX-NH2.

[0111] The thickness of the organic layer is preferably in the range of 0.1 to 10 μm. Having a certain thickness allows it to fully function as a protective film. Furthermore, not being too thick does not hinder the deformation of the diaphragm in the bend mode or the deformation of the drive wall in the shear mode. The thickness can be controlled by adjusting the film formation conditions and the amount of raw material added.

[0112] (2) Inorganic layer The inorganic layer contains inorganic compounds as its main component. Here, "main component" means that it is present in an amount of 85% by mass or more of the total mass of the inorganic layer. Preferably, the inorganic compound content is 90% by mass or more, and more preferably 95% by mass or more, of the total mass of the inorganic layer.

[0113] The type of inorganic compound is not limited, but it is preferable that it is an inorganic compound that can form a dense inorganic thin film. This suppresses the occurrence of thickness variations and defects, and makes the thickness of the inorganic layer uniform.

[0114] Methods for forming the inorganic layer include chemical vapor deposition (CVD), sputtering, molecular layer deposition (MLD), and atomic layer deposition (ALD). From the viewpoint of enabling low-temperature film formation and the density of the resulting film, the inorganic layer is preferably formed by chemical vapor deposition (CVD), sputtering, or atomic layer deposition (ALD). Furthermore, atomic layer deposition (ALD) allows inorganic compounds to be supplied to even complex structures, enabling the formation of a layer of uniform thickness.

[0115] Examples of inorganic compounds include metal oxides, metal nitrides, metal carbides, and allotropes of carbon. Examples of allotropes of carbon include diamond-like carbon (DLC). The inorganic compound is preferably a metal oxide, and examples include oxides of aluminum, silicon, titanium, hafnium, magnesium, zirconium, or tantalum. Among these, oxides of aluminum, silicon, titanium, hafnium, or tantalum are preferred. Specific examples of metal oxides include Al2O3, SiO2, TiO2, HfO2, MgO, ZrO2, and Ta2O5.

[0116] The metal oxide may be a composite oxide of two or more metals selected from the above metals. Furthermore, the inorganic layer may contain a mixture of multiple metal oxides.

[0117] In the formation of an inorganic layer by atomic layer deposition (ALD), a precursor is first sublimated and adsorbed onto the lower layer surface. Here, "lower layer" refers to the substrate layer adjacent to the inorganic layer, which in the example shown in Figures 5 and 6 corresponds to the first organic layer 41. Next, the inorganic layer is formed by exposing the precursor to an oxidizing gas. The deposition of the inorganic layer is carried out in a vacuum chamber.

[0118] For example, precursors of Al2O3 include trimethylaluminum (TMA), dimethylaluminum isopropoxide (DMAIP), and dimethylaluminum hydride (DMAH). Precursors of SiO2 include tetraethoxysilane (TEOS; Si(OC2H5)4) and hexamethyldisilazane (HMDS; (CH3)3Si-NH-Si(CH3)3). Precursors of TiO2 include tetrakis(dimethylamino)titanium (TDMAT; Ti[N(CH3)2]4) and TiCl4.

[0119] Examples of precursors for HfO2 include tetrakis(ethylmethylamide)hafnium (TEMAH; Hf[N(CH3)(C2H5)]4). Examples of precursors for ZrO2 include tetrakis(ethylmethylamide)zirconium (TEMAZ; Zr[N(CH3)(C2H5)]4). Examples of precursors for Ta2O5 include tetrachlorotantalum (TaCl4).

[0120] Examples of oxidizing agents include water (H2O), ozone (O3), and O2 plasma.

[0121] In the formation of inorganic layers by atomic layer deposition (ALD), one cycle consists of the adsorption of a precursor and the oxidation of the precursor by an oxidizing agent. The thickness of the inorganic layer can be adjusted by repeating this cycle. The inorganic layer formed in one cycle is usually at the monolayer level.

[0122] The formation of the inorganic layer by sputtering is not particularly limited, and known methods can be applied.

[0123] The inorganic layer may be a single layer or a multilayer film. Examples of multilayer films include films made by stacking single layers of metal oxides selected from Al2O3, SiO2, TiO2, HfO2, and Ta2O5. The number of layers in a multilayer film is not particularly limited. The multilayer film may consist of alternating layers, for example, layers for improving adhesion and layers that are less prone to generating microdefects and have high barrier properties.

[0124] The thickness of the inorganic layer is preferably in the range of 10 to 500 nm, and more preferably in the range of 20 to 100 nm, from the viewpoint of filling in the starting points of minute defects and durability. If the inorganic layer is a multilayer film, it is preferable to adjust the thickness of each film so that the total thickness of the multilayer film falls within the above range.

[0125] [Manufacturing method for inkjet heads] Figure 7 is a flowchart illustrating the manufacturing method of an inkjet head. This manufacturing method involves forming a protective film on the surface of the flow path that comes into contact with the ink only in the actuator, and then joining the actuator, flow path substrate, and nozzle substrate with an adhesive.

[0126] First, the actuator, nozzle substrate, and flow path substrate are fabricated (steps S1-S3). Next, the nozzle substrate and the flow path substrate are joined together (step S4). Finally, the flow path substrate and the actuator are joined together (step S5).

[0127] In the joining process, the parts are bonded together with the aforementioned adhesive and then heated to approximately 80°C. It is preferable to avoid exposing the protective film on the actuator to high temperatures as much as possible. Therefore, it is preferable to join the nozzle substrate and the flow path substrate first, and then join the flow path substrate and the actuator last, that is, to perform step S4 followed by step S5. However, in this embodiment, the protective film has sufficient heat resistance, so it is less likely to deteriorate even if exposed to high temperatures for a long time. In other words, the order of steps S4 and S5 may be reversed.

[0128] Figure 8 is a flowchart illustrating the actuator manufacturing process. First, the actuator base material is formed (step S11). Next, the formed base material is protected with a protective film (step S12). Here, "base material" refers to the components of the actuator that come into contact with the ink. Specifically, in the bend mode, the pressure chamber layer 31 and the diaphragm 32 correspond to the base material, and in the shear mode, the drive electrode 14 corresponds to the base material.

[0129] When the base material contains nickel, it is preferable to form the base material by sputtering or plating. This allows for the formation of a uniform layer with consistent thickness.

[0130] Figure 9 is a flowchart illustrating the protection process. The organic layer of the protective film is formed by the CVD method described above. Details of the CVD method are as described above. The inorganic layer of the protective film is not particularly limited, but it is preferably formed by sputtering or atomic layer deposition. Details of the sputtering and atomic layer deposition methods are as described above. In the flowchart shown in Figure 9, the protective film is configured to have only a first organic layer, an inorganic layer, and a second organic layer, but the protective film may have other layers, and each of the other layers can be formed using conventionally known methods.

[0131] First, a first organic layer is formed on the substrate by CVD (Step S121). Next, an inorganic layer is formed on the formed first organic layer (Step S122). Finally, a second organic layer is formed on the formed inorganic layer by CVD (Step S123). The organic layer may be stabilized by heating after formation.

[0132] It is preferable to form the first organic layer, the inorganic layer, and the second organic layer continuously without opening to the atmosphere from the start of the first organic layer formation step S121 until the end of the second organic layer formation step S123. By forming them continuously, it is possible to suppress the incorporation of impurities originating from atmospheric components at the interfaces of each layer.

[0133] The layer formation by the CVD method is preferably carried out at room temperature (25°C) ± 10°C, i.e., within the range of 15 to 35°C, and more preferably within the range of room temperature (25°C) ± 5°C, i.e., within the range of 20 to 30°C. The heat treatment after layer formation is preferably carried out at a range of 60 to 150°C, and more preferably within the range of 80 to 120°C. Heating within the above range makes the layer less prone to deformation even in subsequent high-temperature environments.

[0134] In the step of heating the second organic layer, both the first and second organic layers are essentially heated. Therefore, the step of heating the first organic layer can be omitted, but it is preferable to perform the step of heating the first organic layer. By causing the first organic layer to shrink once and changing its crystal structure before forming the inorganic layer and the second organic layer, deformation of the first organic layer during the heating of the second organic layer can be suppressed. As a result, a decrease in adhesion between the substrate and the first organic layer, and between the first organic layer and the inorganic layer, can be suppressed.

[0135] As an alternative manufacturing method, each substrate may be joined with an adhesive, and then a protective film may be formed over the entire surface that comes into contact with the ink. In this embodiment, a uniform and even protective film can be formed even on the surface of the channel where multiple different materials are joined, so this method can also adequately protect the channel.

[0136] [Inkjet recording device] Figure 10 is a schematic diagram showing the general configuration of the inkjet recording device 100 of this embodiment. The inkjet recording device 100 includes a transport unit 110 and a recording unit 120 having a plurality of line heads 121, etc.

[0137] The transport unit 110 (moving means) comprises a first transport roller 111, a second transport roller 112, and a transport belt 113. The first transport roller 111 and the second transport roller 112 rotate around a rotation axis extending to the left in Figure 10. The transport belt 113 is a ring-shaped belt whose inner side is supported by the first transport roller 111 and the second transport roller 112. The transport belt 113 moves in a circular motion around the first transport roller 111 and the second transport roller 112 as the first transport roller 111 rotates in response to the operation of a transport motor (not shown). The transport unit 110 transports the recording medium M in the direction of movement of the transport belt 113 (forward direction in Figure 10) by having the transport belt 113 move in a circular motion with the recording medium M placed on the transport surface of the transport belt 113. In other words, the transport unit 110 moves the line head 121 of the recording unit 120 and the recording medium M relative to each other in the forward direction.

[0138] The recording medium M may be, for example, a sheet of paper cut to a certain size. The recording medium M is supplied onto the conveyor belt 113 by a paper feeder (not shown), and ink is ejected from the line head 121 to record an image. After that, the recording medium M is discharged from the conveyor belt 113 to a predetermined paper discharge section. A long medium such as roll paper may be used as the recording medium M. Examples of recording medium M include plain paper, coated paper, cloth, or sheet-like resin.

[0139] The recording unit 120 is equipped with four line heads 121, each corresponding to one of four ink colors: yellow (Y), magenta (M), cyan (C), and black (K). The line heads 121 eject ink at appropriate timings based on image data onto the recording medium M transported by the transport unit 110 to record an image. The four line heads 121 are arranged from the upstream side in the transport direction (forward direction) of the recording medium M, for example, in the order of colors Y, M, C, and K, at predetermined intervals. The number of line heads 121 can be changed depending on the number of colors used, and may be three or fewer, or five or more.

[0140] Figure 11 is a schematic diagram of the line head 121 as viewed from the conveyor belt 113 side. The line head 121 has multiple inkjet heads 1, each provided with multiple nozzles 51 for ejecting ink. In each inkjet head 1, the multiple nozzles 51 are arranged in the left-right direction to form a nozzle row. Alternatively, as shown in Figure 11, two inkjet heads 1 may be combined to form a single head module 101.

[0141] Furthermore, the detailed configuration of each device constituting the inkjet head can also be modified as appropriate without departing from the spirit of the present invention. [Examples]

[0142] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, the units "parts" or "%" are used, and unless otherwise specified, they represent "parts by mass" or "mass%". Furthermore, in the following examples, the operations were carried out at room temperature (25°C) unless otherwise specified.

[0143] For the bend mode actuator of the inkjet head "KM800 series" (manufactured by Konica Minolta, Inc.), the protective film on the surface in contact with the ink was replaced with a protective film having the configuration shown in Table I to obtain actuators (ACTs) for each comparative example or example. The substrate material of the actuator was nickel. The following compounds were used for PPX and PPX-NH2. n1, n21, n22, and n3 represent the polymerization number.

[0144] [ka]

[0145] (Example 1) In Example 1 (ACT1), a 1 μm thick layer of PPX[P-1] was formed as the first layer of the protective film on the surface of the actuator that comes into contact with the ink, using a vapor deposition apparatus (manufactured by SCS). Specifically, a monochloroparaxylylene dimer was used as the film-forming material, and the dimer was sublimated in a sublimation furnace and then decomposed in a pyrolysis furnace. The surface of the actuator that comes into contact with the ink (the surface on which the protective film will be formed) was exposed to the resulting vapor at a film-forming pressure of 40 mTorr and room temperature (25°C) to form the first layer.

[0146] Next, an inorganic layer was formed on the first layer as the second protective layer. The inorganic layer consisted of two layers, formed in the order of Al2O3 layer followed by TiO2 layer from the first layer side. The inorganic layer was formed by atomic layer deposition using the atomic layer deposition system "R-200Advanced" (manufactured by PICOSUN).

[0147] The Al2O3 layer was formed on the first layer with a thickness of 0.04 μm (40 nm) by alternating exposure to trimethylaluminum (TMA) and water at a deposition temperature of 100°C. The TiO2 layer was formed on the Al2O3 layer with a thickness of 0.01 μm (10 nm) by alternating exposure to tetrakis(dimethylamino)titanium (TDMAT) and water at a deposition temperature of 100°C. The total thickness of the second layer was 0.05 μm (50 nm).

[0148] Next, as the third protective layer, a 4 μm thick layer of PPX-NH2[N-1] was formed on the second layer using a vapor deposition apparatus (manufactured by SCS Corporation). Specifically, dimers of dichloroparacyclophane and aminoparacyclophane were used as the film-forming material, and these dimers were sublimated. The resulting vapor was used to form the third layer by exposing the surface of the actuator that comes into contact with the ink (the surface forming the protective film) to the vapor at a deposition pressure of 40 mTorr and room temperature (25°C).

[0149] Next, ACT1 underwent heat treatment. The actuator was heated at 100°C for 3 hours. This heat treatment was intended to bond the actuator, the flow path substrate, and the nozzle substrate using a thermosetting adhesive.

[0150] (Examples 2-5 and Comparative Examples 1-2) Actuators (ACT2-7) were manufactured using the same procedure as in Example 1, except that the material and thickness of the first layer (first organic layer), the material and thickness of the third layer (second organic layer), and the heat treatment conditions were changed as described in Table I.

[0151] Table I below shows the composition of the protective film and the heat treatment conditions for each actuator.

[0152] [Table 1]

[0153] The following durability tests were conducted on the KM800 inkjet head (manufactured by Konica Minolta, Inc.) equipped with the obtained actuator. The KM800 has 800 nozzles and 800 corresponding drive elements. Each drive element has a predetermined electrical capacity, and the normal operation of the drive function can be determined by measuring the electrical capacity of the drive element. The ink used was a reactive dye ink, specifically pure ink (cyan, manufactured by Konica Minolta, Inc.) for the Nassenger inkjet textile printer. Note that this reactive dye ink is an acidic water-based ink, and corrosion is particularly likely to occur if the actuator's substrate is made of metal such as nickel.

[0154] <Driving conditions> Drive unit: Inkjet control system "IJCS-1" (manufactured by Konica Minolta, Inc.) Applied voltage: 17V Frequency: 40kHz Test temperature: Room temperature (25℃)

[0155] <Evaluation Method> The capacitance of each drive element was measured after each number of applied pulses shown in Table II. Drive elements whose capacitance was outside of ±20% of the initial value were judged to be abnormal. The inkjet head was evaluated to see if it was functioning correctly according to the following criteria. AA and A were considered acceptable, indicating no practical problems. AA: All 800 drive elements exhibit normal capacitance. A: Out of 800 drive elements, 1 to 2 exhibit abnormal capacitance. B: Of the 800 drive elements, three or more exhibit abnormal capacitance.

[0156] The evaluation results are shown in Table II below.

[0157] [Table 2]

[0158] From the comparative examples and examples, it can be seen that by using the protective film of this embodiment, that is, by having a layer of PPX-NH2, the heat resistance of the inkjet head is improved. Furthermore, although the actuator has many uneven structures such as corners, edges, and steps, a protective film of uniform thickness is formed even in these uneven structures, and as a result, the durability of the inkjet head is improved.

[0159] Examples 1 and 2 show that heat resistance is improved by positioning the PPX-NH2 layer on the side that comes into contact with the ink.

[0160] Examples 1, 3, and 4 show that the protective film of this embodiment has sufficient heat resistance even when subjected to high temperature and prolonged heat treatment. Furthermore, Example 5 shows that the protective film of this embodiment has improved heat resistance by having PPX-NH2 layers in both the first layer (first organic layer) and the third layer (second organic layer).

[0161] By using the present invention, the thickness of the protective film can be made uniform, and its heat resistance can be improved. As a result, the lifespan of the inkjet head having the protective film and the inkjet recording device (printer) equipped with the inkjet head can be extended. [Explanation of Symbols]

[0162] 1. Inkjet head 2 Adhesive layer 4 Protective film 6 cabinets 7 Cover component 11 drive channels 12 Dummy Channels 13 Drive Wall 14. Drive electrode 15 Connecting electrodes 21 Supply channel 22 Pressure chamber 23 Supply side communication channel 24 Nozzle-side communication channel 30 Actuators 31 Pressure chamber layer 32 Diaphragm 33 Insulating layer 34 Piezoelectric layer 35 Electrode layer 40 Flow channel substrate 41 1st organic layer 42 Inorganic layer 43 Second organic layer 44 4th layer 45 5th layer 50 Nozzle substrates 51 nozzles 60 Ink 61 Droplets 68 mounting holes 70-layer structure 71 Base material 100 Inkjet Recording Devices 101 Head Module 110 Conveying section 111 First conveyor roller 112 Second conveyor roller 113 Conveyor belt 120 Records Section 121 Line Head

Claims

1. It has, in order, a first organic layer, an inorganic layer, and a second organic layer. The first organic layer and the second organic layer contain polyparaxylylene or a derivative thereof having a structure represented by the following general formula (1), or a derivative of polyparaxylylene having a structure represented by the following general formula (2). A protective film in which at least one of the first organic layer and the second organic layer contains a polyparaxylylene derivative having a structure represented by the following general formula (2). 【Chemistry 1】 In general formula (1), each of the a X1 atoms independently represents an alkyl group having 1 to 5 carbon atoms, or a halogen atom. a represents an integer from 0 to 4. n1 represents the polymerization number. 【Chemistry 2】 In general formula (2), each of the b X2 atoms independently represents an alkyl group having 1 to 5 carbon atoms, or a halogen atom. b is an integer from 0 to 4. n2 represents the number of polymerization units. Each of the c X3 atoms independently represents an alkyl group having 1 to 5 carbon atoms. c is an integer from 0 to 3. d is an integer from 1 to 4. n3 represents the number of polymerization units.

2. The protective film according to claim 1, wherein the second organic layer contains a derivative of polyparaxylylene having the structure represented by the general formula (2).

3. The protective film according to claim 1, wherein both the first organic layer and the second organic layer contain a derivative of polyparaxylylene having the structure represented by the general formula (2).

4. The protective film according to claim 1, wherein the thickness of the first organic layer is in the range of 0.1 to 10 μm.

5. The protective film according to claim 1, wherein the thickness of the second organic layer is in the range of 0.1 to 10 μm.

6. The protective film according to claim 1, wherein the thickness of the inorganic layer is in the range of 10 to 500 nm.

7. The protective film according to claim 1, wherein the inorganic layer includes a film containing an oxide of aluminum, silicon, titanium, hafnium, or tantalum.

8. A method for manufacturing a protective film according to any one of claims 1 to 7, The first organic layer formation step involves forming the first organic layer described above, An inorganic layer formation step is performed to form the inorganic layer on the first organic layer that has been formed, The process includes a step of forming a second organic layer on the inorganic layer formed, A method for manufacturing a protective film, comprising forming the inorganic layer in the inorganic layer formation step using chemical vapor deposition, sputtering, or atomic layer deposition.

9. It has a channel through which the ink flows, The surface of the channel has a protective film according to any one of claims 1 to 7, An inkjet head in which the first organic layer is located on the surface side of the flow channel and the second organic layer is located on the side that comes into contact with the ink.

10. The inkjet head according to claim 9, wherein the surface of the flow channel has an uneven structure.

11. The inkjet head according to claim 9, wherein the surface of the flow channel exposes an adhesive and substrates of multiple different materials.

12. It comprises an actuator, a flow path substrate, and a nozzle substrate, The inkjet head according to claim 9, wherein the actuator, the flow channel substrate, and the nozzle substrate are joined together with an adhesive.

13. A method for manufacturing an inkjet head as described in claim 12, The aforementioned protective film is exposed to an environment of 80°C or higher in the method for manufacturing an inkjet head.

14. An inkjet recording apparatus comprising the inkjet head described in claim 12.

Images