Dispensing head

Abstract

To provide a coating head capable of improving tolerance of liquid contact surfaces to an ink.SOLUTION: A coating head includes: nozzles; pressure chambers communicating with the nozzles; and an ink passage communicating with the pressure chambers. A coating layer is provided in at least part of liquid contact surfaces of the nozzles, the pressure chambers, and the ink passage.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a coating head.

Background Art

[0002] In recent years, inkjet coating devices have been used in the manufacture of electronic devices such as liquid crystal panels and organic EL panels. As an example of a coating head, a drop-on-demand type coating head that can eject a required amount of ink droplets at a required timing with high-frequency driving (for example, 50 kHz) with high precision onto a coating object is known. This type of coating head generally includes an ink flow path, a pressure chamber connected to the ink flow path for storing ink, a piezoelectric element (piezo element) for pressurizing the ink stored in the pressure chamber, and a nozzle communicating with the pressure chamber (see, for example, Patent Document 1). By applying electricity to the piezoelectric element to pressurize the ink in the pressure chamber, ink droplets are ejected from the nozzle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When manufacturing an electronic device using a coating device, it is necessary to inkify various materials, and in some cases, inkification is performed using a solvent with strong solubility. Ink containing such a solvent with strong solubility may dissolve the liquid contact part of the coating head. In particular, when a plurality of plates are laminated and the plates are joined by an adhesive to form a coating head, the adhesive layer is exposed on the liquid contact surface and is easily damaged by the solvent.

[0005] An object of the present disclosure is to provide a coating head that can improve the resistance of the liquid contact surface to ink. [Means for solving the problem]

[0006] A coating head relating to one aspect of this disclosure is Multiple nozzles, Multiple pressure chambers communicating with multiple nozzles, It comprises an ink channel that communicates with a plurality of pressure chambers, A coating layer is provided on at least a portion of the wetted surfaces of the nozzle, the pressure chamber, and the ink flow path. Occasionally, The nozzle, the pressure chamber, and the ink flow path are formed by laminating and bonding a nozzle plate, a pressure chamber plate, and a diaphragm plate. The first adhesive layer interposed between the nozzle plate and the pressure chamber plate, and the second adhesive layer interposed between the pressure chamber plate and the diaphragm plate, form a part of the wetted surface. The coating layer includes a layer made of a highly chemical-resistant material that is not dissolved by the ink, and covers the first adhesive layer and the second adhesive layer, and furthermore, the portion corresponding to the first adhesive layer and the second adhesive layer is thicker than the other portion. . Furthermore, a coating head according to one aspect of this disclosure is Multiple nozzles, Multiple pressure chambers communicating with multiple nozzles, It comprises an ink channel that communicates with a plurality of pressure chambers, A coating layer is provided on at least a portion of the wetted surfaces of the nozzle, the pressure chamber, and the ink flow path. The nozzle, the pressure chamber, and the ink flow path are formed by laminating and bonding a nozzle plate, a pressure chamber plate, and a diaphragm plate. The first adhesive layer interposed between the nozzle plate and the pressure chamber plate, and the second adhesive layer interposed between the pressure chamber plate and the diaphragm plate, form a part of the wetted surface. The aforementioned coating layer has a laminated structure consisting of three or more layers. The laminated structure includes a first coating layer made of a highly chemical-resistant material that is not dissolved by the ink, a second coating layer located at the bottom and having the highest adhesion to the wetted surface compared to the other layers, and a third coating layer located at the outermost surface and having the highest wettability compared to the other layers. . [Effects of the Invention]

[0007] According to this disclosure, the resistance of the wetted surface to ink can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an exploded perspective view showing the external appearance of the coating head according to the embodiment. [Figure 2] Figure 2 is a schematic diagram showing a coating head according to an embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing an example of an ink flow path in a coating head. [Figure 4] Figure 4 is a schematic cross-sectional view showing an example of an ink flow path in a coating head. [Figure 5]Figs. 5A to 5C are diagrams showing an example of a coating layer. [Figure 6] Figs. 6A to 6D are transition diagrams showing an example of a state in which ink is introduced into an ink flow path. [Figure 7] Figs. 7A to 7D are transition diagrams showing an example of a state in which ink is introduced into an ink flow path. [Figure 8] Fig. 8 is a flowchart showing an example of a manufacturing process of a coating head. [Figure 9] Fig. 9 is a cross-sectional view schematically showing another example of an ink flow path in a coating head. [Figure 10] Fig. 10 is a cross-sectional view schematically showing another example of an ink flow path in a coating head.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, the coating head 1 according to the embodiment of the present disclosure will be described with reference to the drawings. The coating head 1 is, for example, an ink circulation type coating head. In the present disclosure, an orthogonal coordinate system (X, Y, Z) is used for the description. The positive direction of the Z-axis is the ink ejection direction in the coating head 1, the direction along the X-axis is the arrangement direction of the nozzles 101, and the direction along the Y-axis is the ink flow direction in the ink flow paths (upstream individual flow paths 103 and downstream individual flow paths 104) connected to the pressure chambers 102. Hereinafter, the directions along the X-axis, Y-axis, and Z-axis are referred to as the "X-axis direction", "Y-axis direction", and "Z-axis direction", respectively.

[0010] Fig. 1 is an exploded perspective view showing the appearance of the coating head 1 according to the embodiment. Fig. 2 is a diagram schematically showing the coating head according to the embodiment. Figs. 3 and 4 are cross-sectional views schematically showing the ink flow paths in the coating head 1. Fig. 3 shows the A-A cross-section in Fig. 2, and Fig. 4 shows the B-B cross-section in Fig. 2.

[0011] As shown in Figures 3 and 4, the coating head 1 includes a nozzle 101, a pressure chamber 102, an upstream individual channel 103, a downstream individual channel 104, an upstream common channel 105, a downstream common channel 106, and a piezoelectric element 107, etc. The nozzle 101, pressure chamber 102, upstream individual channel 103, downstream individual channel 104, upstream common channel 105, and downstream common channel 106 are formed inside the nozzle plate 10, pressure chamber plate 20, vibration plate 30, and housing 40, or by being coupled together.

[0012] The nozzle plate 10 is positioned so that its surface is perpendicular to the Z-axis. The nozzle plate 10 is formed from a stainless steel plate, for example, by etching or press working. The thickness of the stainless steel plate is, for example, 100 μm.

[0013] The pressure chamber plate 20 has a rectangular parallelepiped shape and is positioned on the negative side of the nozzle plate 10 in the Z-axis direction, with its plate surface perpendicular to the Z-axis. The pressure chamber plate 20 is sandwiched between the vibrating plate 30 and the nozzle plate 10. The pressure chamber plate 20 is a laminate of multiple stainless steel plates formed, for example, by etching or press working. The thickness of each stainless steel plate is, for example, 10 to 100 μm, and the number of layers is, for example, 3 to 10 layers.

[0014] The vibrating plate 30 is positioned on the negative side of the pressure chamber plate 20 in the Z-axis direction, with its plate surface perpendicular to the Z-axis. The vibrating plate 30 is sandwiched between the housing 40 and the pressure chamber plate 20. The vibrating plate 30 is, for example, a thin film with a thickness of 5 to 50 μm, and is formed, for example, by nickel electroplating. The vibrating plate 30 has a pressure-receiving portion 33 that receives fluctuations from the piezoelectric element 107. The pressure-receiving portion 33 is provided corresponding to each of the plurality of pressure chambers 102 and is formed, for example, protruding on the negative side in the Z-axis direction.

[0015] The housing 40 has a rectangular parallelepiped shape and is positioned on the negative side of the vibrating plate 30 in the Z-axis direction. The housing 40 has a thickness of, for example, 1 cm in the Z-axis direction. The housing 40 is formed by machining, for example, an alloy steel such as stainless steel.

[0016] The pressure fluctuation unit 50 is located in a housing chamber (not shown) formed in the housing 40. The pressure fluctuation unit 50 has a piezoelectric element 107.

[0017] The nozzle plate 10 and the pressure chamber plate 20, the pressure chamber plate 20 and the vibrating plate 30, the vibrating plate 30 and the housing 40, and the vibrating plate 30 and the pressure fluctuation section 50 are each bonded and fixed with adhesive. For example, an epoxy adhesive with thermosetting properties is used as the adhesive. The adhesive used to bond each component may be the same adhesive or different adhesives.

[0018] A first adhesive layer 61 is interposed between the nozzle plate 10 and the pressure chamber plate 20. A second adhesive layer 62 is interposed between the pressure chamber plate 20 and the vibrating plate 30. The first adhesive layer 61 and the second adhesive layer 62 form part of the pressure chamber 102, the upstream common flow path 105, and the downstream common flow path 106. In other words, the first adhesive layer 61 and the second adhesive layer 62 become the liquid-contacting surfaces in the ink flow path. The first adhesive layer 61 and the second adhesive layer 62 contain organic matter and are easily dissolved by the ink, so they are parts that particularly require protection by the coating layer 70. A third adhesive layer 63 is interposed between the vibrating plate 30 and the piezoelectric element 107.

[0019] Multiple nozzles 101 are drilled in the nozzle plate 10 along the X-axis. A nozzle 101 is a hole that penetrates the nozzle plate 10 in the Z-axis direction. Ink droplets are ejected to the outside through the nozzles 101. The diameter of the nozzles 101 is, for example, 3 to 100 μm. The nozzles 101 may be arranged in one row or in multiple rows along the X-axis. In Figure 1, the nozzles 101 are arranged in two rows along the X-axis. When the nozzles 101 are arranged in multiple rows, a pressure chamber 102, an upstream individual channel 103, a downstream individual channel 104, an upstream common channel 105, and a downstream common channel 106 are provided for each nozzle row.

[0020] The pressure chamber 102 is formed when the open surface (the negative side in the Z-axis direction) of a recess formed in the pressure chamber plate 20 is closed by the vibration plate 30. The pressure chamber 102 is an ink storage space for storing ink. A pressure chamber 102 is provided one-to-one for each of the multiple nozzles 101 and communicates with the nozzles 101. The pressure chamber 102 has, for example, a rectangular parallelepiped shape extending along the Y-axis. Steps may be formed on the inner surface of the pressure chamber 102.

[0021] The upstream individual flow channels 103 are located upstream of the pressure chamber 102 in the ink flow direction and connect the pressure chamber 102 to the upstream common flow channel 105. One upstream individual flow channel 103 is provided for each of the multiple pressure chambers 102.

[0022] The downstream individual channel 104 is located downstream of the pressure chamber 102 in the ink flow direction and connects the pressure chamber 102 to the downstream common channel 106. A downstream individual channel 104 is provided one to one for each of the multiple pressure chambers 102.

[0023] The upstream common channel 105 is an ink storage space located upstream of the upstream individual channels 103 in the ink flow direction. The upstream common channel 105 is provided in common for multiple upstream individual channels 103. The upstream common channel 105 communicates with an ink supply passage (not shown) formed in the housing 40 through an opening 31 formed in the vibrating plate 30.

[0024] The downstream common channel 106 is an ink storage space located downstream of the downstream individual channels 104 in the ink flow direction. The downstream common channel 106 is provided in common for multiple downstream individual channels 104. The downstream common channel 106 communicates with an ink discharge channel (not shown) formed in the housing 40 through an opening 32 formed in the vibrating plate 30.

[0025] The piezoelectric elements 107 are provided corresponding to a plurality of pressure chambers 102 and are in contact with the pressure-receiving portion 33 of the vibrating plate 30. By applying a voltage, the piezoelectric elements 107 deform, for example, by expanding and contracting in the Z-axis direction. For example, a D33 mode stacked piezoelectric actuator is used for the piezoelectric elements 107.

[0026] In the coating head 1, ink supplied from an external ink supply tank (not shown) via an ink supply passage (not shown) in the housing 40 is supplied to the pressure chamber 102 via an upstream common passage 105 and an upstream individual passage 103, and is discharged from the ink discharge passage (not shown) via a downstream individual passage 104 and a downstream common passage 106. The discharged ink is circulated back to the ink supply tank by, for example, a circulation pump (not shown). By circulating the ink in this way without allowing it to stagnate, it is possible to prevent ink from accumulating in the pressure chamber 102 or nozzle 101 and causing nozzle clogging.

[0027] In the ink-circulating type coating head 1, the pressure in the ink supply tank (not shown) connected to the ink supply passage (not shown) is set to be higher than the pressure in the ink discharge tank (not shown) connected to the ink discharge passage (not shown). For example, the pressure difference can be controlled by making the positions of the ink supply tank and the ink discharge tank in the Z-axis direction (height relative to the pressure chamber 102) different. Alternatively, for example, the internal pressure of the ink supply tank and the ink discharge tank may be controlled individually by regulators.

[0028] In the coating head 1, when a voltage is applied to the piezoelectric element 107, the piezoelectric element 107 deforms, for example, by stretching in the Z-axis direction, and vibrations in the Z-axis direction are transmitted to the pressure receiving portion 33 of the vibrating plate 30. As a result, the vibrating plate 30 deforms, causing pressure fluctuations in the ink stored in the pressure chamber 102. These pressure fluctuations propagate toward the nozzle 101, causing ink droplets to be ejected from the nozzle 101.

[0029] In this embodiment, a coating layer 70 is provided on the entire wetted surface of the nozzle 101, pressure chamber 102, upstream individual channel 103, downstream individual channel 104, upstream common channel 105, and downstream common channel 106. By providing the coating layer 70, it is possible to prevent the ink channels, including the nozzle 101, pressure chamber 102, and the upstream individual channel 103, downstream individual channel 104, upstream common channel 105, and downstream common channel 106, from being dissolved by the ink. Generally, a strongly soluble solvent (for example, N,N-dimethylformamide CAS68-12-2) is used for the ink.

[0030] The coating layer 70 is required to have chemical resistance that prevents it from being dissolved by the ink, high adhesion to the substrate (e.g., nozzle plate 10), and high wettability (e.g., contact angle of 30° or less). These properties can be achieved, for example, by making the coating layer 70 a laminated structure.

[0031] Figures 5A to 5C show an example of the structure of the coating layer 70. Figures 5A to 5C show a magnified view of the area enclosed by the dashed line C in Figure 4.

[0032] The coating layer 70 shown in Figure 5A has a single-layer structure. The coating layer 70 includes a first coating layer 71 formed of a highly chemical-resistant material that is not dissolved by the ink. The first coating layer 71 is, for example, a resin film, a metal film, or a metal oxide film. In the case of a resin film, parylene resin is preferred, for example. In the case of a metal film, gold, niobium, and tantalum are preferred, for example. In the case of a metal oxide film, alumina, titanium oxide, niobium oxide, and other metals are preferred. tantalumSilicon oxide is preferred.

[0033] In particular, when the first coating layer 71 is a metal oxide film, a thin film coating of only a few atomic layers is possible, resulting in minimal change in the dimensions of the pressure chamber 102. Furthermore, variations in film thickness can be suppressed during the film deposition process. Consequently, the discharge performance between the multiple nozzles 101, which are provided to correspond to the multiple pressure chambers 102, becomes stable.

[0034] The coating layer 70 shown in Figure 5B has a two-layer structure. The two-layer coating layer 70 includes a first coating layer 71 made of a highly chemical-resistant material, and a second coating layer 72 at the bottom, which is in contact with the substrate (the nozzle plate 10 in Figure 5B), and has higher adhesion to the substrate than the first coating layer 71. When the substrate is made of stainless steel, titanium oxide is preferred for the second coating layer 72, for example.

[0035] When the coating material and film formation process are determined with the aim of preventing dissolution by ink, adhesion to the substrate may be sacrificed, and there is a risk that the coating layer 70 will peel off over time. By making the coating layer 70 a two-layer structure and providing a second coating layer 72 with high adhesion to the substrate as the bottom layer, the peeling of the coating layer 70 can be easily suppressed.

[0036] In addition, in a two-layer coating layer 70, if the adhesion of the first coating layer 71 to the substrate is high, the first coating layer 71 may be made the bottom layer, and a third coating layer 73 with high wettability may be formed on its surface.

[0037] The coating layer 70 shown in Figure 5C has a three-layer structure. The three-layer coating layer 70 includes a first coating layer 71 and a second coating layer 72, as well as a third coating layer 73 on the outermost surface, which has a higher surface tension than the ink. The third coating layer 73 has higher wettability than the second coating layer 72, resulting in a smaller contact angle with the ink. The contact angle of the third coating layer 73 is 30° or less, preferably 10° or less. By providing the third coating layer 73, the contact angle of the liquid-contacting surface can be easily reduced.

[0038] Figures 6A to 6D and 7A to 7D are transition diagrams showing the process of filling the ink channel 111 in the coating head. The coating head 1 shown in Figures 7A to 7D uses a coating layer 70 with higher wettability compared to the coating head shown in Figures 6A to 6D.

[0039] If the wettability of the coating layer 70 is low (for example, if the contact angle is 90°), the ink supplied from the supply tank (not shown) flows into the pressure chamber 102 via the upstream common channel 105 and the upstream individual channels 103 (see Figure 6A). The ink 111 travels along the wetted surface of the pressure chamber 102. At this time, because the contact angle of the coating layer 70 is large, the ink travels mainly due to external pressure and does not spread and wet the wetted surface (see Figure 6B). As a result, the corners of the pressure chamber 102 are not filled with ink 111 (see Figure 6C) and remain in the pressure chamber 102 as air bubbles 112. If air bubbles 112 are mixed into the pressure chamber 102, the pressure fluctuations within the pressure chamber 102 are mitigated by the air bubbles 112, which may cause poor ink discharge.

[0040] On the other hand, if the wettability of the coating layer 70 is high (for example, if the contact angle is 10° or less), the ink supplied from the supply tank (not shown) flows into the pressure chamber 102 via the upstream common channel 105 and the upstream individual channel 103 (see Figure 7A). The ink 111 travels along the wetted surface of the pressure chamber 102. At this time, because the contact angle of the coating layer 70 is small, the ink travels mainly by wetting and spreading forces, and spreads wetly across the wetted surface (see Figure 7B). As a result, the ink fills the pressure chamber 102 completely without any gaps, including the corners (see Figure 7C), and no air bubbles remain in the pressure chamber 102. Therefore, the ink discharge quality is improved. In addition, when the ink flows from the upstream individual channel 103 into the pressure chamber 102, the surface tension of the liquid surface does not hinder the flow of ink into the pressure chamber 102, allowing the ink to flow smoothly.

[0041] Figure 8 shows an example of the manufacturing process for the coating head 1.

[0042] First, in step S1, individual plates 10 to 30 are prepared. For example, for nozzle plate 10, a water-repellent film is formed on the nozzle surface (the positive side in the Z-axis direction), and then nozzle holes are formed. For pressure chamber plate 20, multiple plates with openings that serve as ink channels are stacked and bonded together.

[0043] Next, in step S2, the nozzle plate 10 and the pressure chamber plate 20 are joined together with an adhesive. A first adhesive layer 61 is formed between the nozzle plate 10 and the pressure chamber plate 20 (see Figures 3 and 4).

[0044] Next, in step S3, the joint of the nozzle plate 10 and the pressure chamber plate 20 is joined to the vibrating plate 30 with an adhesive. A second adhesive layer 62 is formed between the pressure chamber plate 20 and the vibrating plate 30 (see Figures 3 and 4).

[0045] Next, in step S4, a coating layer 70 is formed on the joint of the nozzle plate 10, pressure chamber plate 20, and vibrating plate 30. For forming the coating layer 70, atomic layer deposition (ALD) is preferred, for example. The coating layer 70 is formed on the surface of the ink channel formed by the nozzle plate 10, pressure chamber plate 20, and vibrating plate 30. By using atomic layer deposition, the coating material can penetrate even into the narrow space of the ink channel, and the coating layer 70 can be formed with a uniform thickness. In addition, since the coating process is performed after the nozzle plate 10, pressure chamber plate 20, and vibrating plate 30 are joined, the coating layer 70 is also formed on the surfaces of the first adhesive layer 61 and the second adhesive layer 62.

[0046] After the coating is completed, in step S5, the assembled nozzle plate 10, pressure chamber plate 20, and vibration plate 30 are joined to the piezoelectric element 107 with an adhesive. A third adhesive layer 63 is formed between the vibration plate 30 and the piezoelectric element 107 (see Figures 3 and 4).

[0047] Note that steps S2 and S3 can be performed in any order. Also, in steps S2 and S3, the plates may be joined together by metal diffusion bonding instead of adhesive bonding.

[0048] As described above, the coating head according to this embodiment comprises a plurality of nozzles 101, a plurality of pressure chambers 102 communicating with the plurality of nozzles 101, ink channels (upstream common channel 105, upstream individual channels 103, downstream individual channels 104, and downstream common channel 106) communicating with the plurality of pressure chambers 102, and a piezoelectric element 107 that deforms when energized to pressurize the ink in the pressure chambers 102. A coating layer 70 is provided on at least a portion of the wetted surfaces of the nozzles 101, pressure chambers 102, and ink channels 103 to 106. As a result, the wetted surface's resistance to ink is improved with respect to the portion covered by the coating layer 70, thus improving the reliability of the coating head 1.

[0049] Furthermore, in the coating head 1, the coating layer 70 includes a first coating layer 71 formed of a metal oxide. This makes it easy to improve the resistance of the liquid-contacting surface to the ink. In addition, since a thin film coating of only a few atomic layers is possible, the dimensions of the pressure chamber 102 change little, and variations in film thickness can be suppressed in the film formation process. Therefore, the ejection performance between nozzles is stable.

[0050] Furthermore, in the coating head 1, the coating layer 70 has a multilayer structure consisting of multiple layers. This allows the coating layer 70 to be designed considering not only chemical resistance to ink, but also adhesion to the substrate and ink wettability.

[0051] Furthermore, in the coating head 1, the second coating layer 72 (bottommost layer) of the coating layer 70 has the highest adhesion to the liquid contact surface compared to the other layers. This makes it possible to suppress the peeling of the coating layer 70 from the substrate over time.

[0052] Furthermore, in the coating head 1, the third coating layer 73 (outermost layer) of the coating layer 70 has the highest wettability compared to the other layers. Specifically, the third coating layer 73 (outermost layer) has a contact angle of 10° or less. This allows ink to flow smoothly into and fill the pressure chamber 102, preventing problems caused by air bubbles remaining in the pressure chamber 102.

[0053] Furthermore, the coating head 1 is formed by laminating and bonding a nozzle plate 10, a pressure chamber plate 20, and a diaphragm plate 30. A first adhesive layer 61 is interposed between the nozzle plate 10 and the pressure chamber plate 20, and a second adhesive layer 62 is interposed between the pressure chamber plate 20 and the diaphragm plate 30, forming a part of the liquid-contacting surface. The coating layer 70 covers the first adhesive layer 61 and the second adhesive layer 62. This protects the adhesive portion, which is more easily dissolved by the ink than the plate.

[0054] Although the present invention has been specifically described above based on embodiments, the present invention is not limited to the above embodiments and can be modified without departing from its spirit.

[0055] For example, the coating layer 70 may be applied not to the entire surface of the wetted surface, but only to the portion made of a material that is easily dissolved by the ink. For example, if the nozzle plate 10 and pressure chamber plate 20 are made of stainless steel and the vibrating plate 30 is made of nickel plating, then depending on the type of ink, only the wetted surface of the vibrating plate 30 may be easily dissolved.

[0056] In this case, the coating layer 70 may be provided only on the wetted surface of the vibrating plate 30. Figure 9 shows an example in which the coating layer 70 is provided on the entire surface of the vibrating plate 30. Since the coating layer 70 can be formed before bonding the plates together, the manufacturing process is simplified. Furthermore, when the coating layer 70 is formed on both sides of the vibrating plate 30, it is possible to reliably prevent the vibrating plate 30 from being dissolved by the ink. Therefore, the vibrating plate will not be damaged and the conductive ink will not come into contact with the piezoelectric element 107, thus preventing short-circuit accidents and improving safety. Note that if the adhesion between the coating layer 70 and the adhesive is poor, the coating layer 70 may not be formed in the areas where the second adhesive layer 62 and the third adhesive layer 63 are formed.

[0057] Furthermore, for example, as shown in Figure 10, when the coating layer 70 covers the first adhesive layer 61 and the second adhesive layer 62, the portion 70a corresponding to the first adhesive layer 61 and the second adhesive layer 62 may be made thicker than the other portions. This allows for more reliable protection of the adhesive portion that is most susceptible to dissolution by the ink.

[0058] Furthermore, fine irregularities may be formed on the outermost layer of the coating layer 70 in order to reduce the contact angle. In addition, this disclosure can be applied not only to the circulating coating head described in the embodiment, but also to a non-circulating coating head.

[0059] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Industrial applicability]

[0060] This disclosure is widely applicable to coating heads and coating apparatus equipped with coating heads. [Explanation of Symbols]

[0061] 1. Dispensing head 10 Nozzle Plates 20 Pressure chamber plate 30 Vibration Plate 61 1st adhesive layer 62 Second adhesive layer 63 Third adhesive layer 70 Coating layer 71 First coating layer 72 Second coating layer 73 Third coating layer 101 Nozzles 102 Pressure Chamber 103 Upstream Individual Channels 104 Downstream individual channel 105 Upstream common channel 106 Downstream common channel 107 Piezoelectric element

Claims

1. Multiple nozzles, Multiple pressure chambers communicating with multiple nozzles, It comprises an ink channel that communicates with a plurality of pressure chambers, A coating layer is provided on at least a portion of the wetted surfaces of the nozzle, the pressure chamber, and the ink flow path. The nozzle, the pressure chamber, and the ink flow path are formed by laminating and bonding a nozzle plate, a pressure chamber plate, and a diaphragm plate. The first adhesive layer interposed between the nozzle plate and the pressure chamber plate, and the second adhesive layer interposed between the pressure chamber plate and the diaphragm plate, form a part of the wetted surface. The coating layer includes a layer made of a highly chemical-resistant material that is not dissolved by the ink, and covers the first adhesive layer and the second adhesive layer, and furthermore, the portion corresponding to the first adhesive layer and the second adhesive layer is thicker than the other portion. Dispensing head.

2. The coating layer includes a layer formed of a metal oxide. The coating head according to claim 1.

3. The coating layer has a laminated structure consisting of multiple layers. The coating head according to claim 1 or 2.

4. The bottom layer of the coating layer has the highest adhesion to the wetted surface compared to the other layers. The coating head according to claim 3.

5. The outermost layer of the aforementioned coating layer has the highest wettability compared to the other layers. The coating head according to claim 3 or 4.

6. The outermost layer has a contact angle of 10° or less. The coating head according to claim 5.

7. Multiple nozzles, Multiple pressure chambers communicating with multiple nozzles, It comprises an ink channel that communicates with a plurality of pressure chambers, A coating layer is provided on at least a portion of the wetted surfaces of the nozzle, the pressure chamber, and the ink flow path. The nozzle, the pressure chamber, and the ink flow path are formed by laminating and bonding a nozzle plate, a pressure chamber plate, and a diaphragm plate. The first adhesive layer interposed between the nozzle plate and the pressure chamber plate, and the second adhesive layer interposed between the pressure chamber plate and the diaphragm plate, form a part of the wetted surface. The aforementioned coating layer has a laminated structure consisting of three or more layers. The laminated structure includes a first coating layer made of a highly chemically resistant material that is not dissolved by ink, a second coating layer located at the bottom and having the highest adhesion to the wetted surface compared to the other layers, and a third coating layer located at the outermost layer and having the highest wettability compared to the other layers. Dispensing head.

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