Inkjet head and printer

Abstract

To provide an inkjet head that is able to reduce breakage of a water-repellent film.SOLUTION: An inkjet head 20 includes: a nozzle plate 24 in which a plurality of nozzles 21, each of which has a nozzle hole 22 for ejecting ink, are formed; a pressure-chamber plate in which a pressure chamber 27b, to which pressure for ejecting the ink from the nozzle hole 22 is applied, is formed; a descender plate in which a descender 27c having a first end 27c1 connected to the pressure chamber 27b and a second end 27c2 connected to the nozzle 21 and having a diameter larger than a diameter of the nozzle 21 is formed, the descender plate being superposed between the nozzle plate 24 and the pressure-chamber plate; and a water-repellent film 60 provided on an ejection surface 24a of the nozzle plate 24 in which the nozzle holes 22 are open. The water-repellent film 60 has an inner peripheral edge 61 overlapping with an edge of the nozzle hole 22 and an outer peripheral edge 62 provided between the inner peripheral edge 61 and an edge of the second end 27c2, as viewed along a layering direction in which the descender plate is superposed on the nozzle plate 24.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inkjet head that ejects ink from nozzles, and a printer that includes an inkjet head. [Background technology]

[0002] A known nozzle plate used in conventional printer inkjet heads is the laminate for a nozzle plate described in Patent Document 1. This laminate for a nozzle plate has a substrate made of a polymeric material with nozzle discharge holes formed therein, and a water-repellent film formed on the discharge surface of the substrate via a primer layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-30707 Summary of the Invention [Problem to be solved by the invention]

[0004] In the nozzle plate laminate of Patent Document 1, ink is ejected through the nozzle ejection holes of the substrate. If the substrate expands due to the ink in the nozzle ejection holes, there is a problem that damage such as peeling or cracking occurs in the water-repellent film provided on the ejection surface of the substrate.

[0005] The present invention has been made to solve these problems, and aims to provide an inkjet head and printer that can reduce damage to the water-repellent film caused by expansion of the nozzle plate by ink. [Means for solving the problem]

[0006] The inkjet head according to the present disclosure comprises a nozzle plate in which a plurality of nozzles each having a nozzle hole for ejecting ink are formed, a pressure chamber plate in which a pressure chamber is formed to which pressure for ejecting ink from the nozzle hole is applied, a descender plate in which a descender having a first end connected to the pressure chamber and a second end connected to the nozzle and having a diameter larger than that of the nozzle is formed and which is stacked between the nozzle plate and the pressure chamber plate, and a water-repellent film provided on the ejection surface of the nozzle plate in which the nozzle hole is opened, when viewed along the stacking direction in which the descender plate is stacked on the nozzle plate, the water-repellent film has an inner peripheral edge that overlaps with the edge of the nozzle hole, and an outer peripheral edge that is provided between the inner peripheral edge and the edge of the second end.

[0007] The inkjet head according to the present disclosure comprises: a nozzle plate in which a plurality of nozzles each having a nozzle hole for ejecting ink are formed; a pressure chamber to which pressure for ejecting ink from the nozzle hole is applied; a flow path plate formed with a descender having a first end connected to the pressure chamber and a second end connected to the nozzle and having a diameter larger than that of the nozzle; and a water-repellent film provided on the ejection surface of the nozzle plate in which the nozzle hole is opened, wherein the water-repellent film has an inner peripheral edge that overlaps the edge of the nozzle hole and an outer peripheral edge provided between the inner peripheral edge and the edge of the second end when viewed along the stacking direction in which the flow path plate is stacked on the nozzle plate.

[0008] A printer according to the present disclosure includes the inkjet head described above. [Effects of the Invention]

[0009] According to the present disclosure, swelling of the nozzle plate due to ink is greater inside the edge of the second end of the descender than outside the edge of the second end. In contrast, the water-repellent film is provided inside the edge of the second end, not outside the edge of the second end. This makes it possible to reduce the difference in the amount of swelling of the nozzle plate in the area where the water-repellent film is provided, compared to when the water-repellent film is provided both inside and outside the edge of the second end. Therefore, even if stress is generated in the water-repellent film provided on the nozzle plate due to swelling of the nozzle plate, the stress in the water-repellent film is reduced compared to when the water-repellent film is provided both inside and outside the edge of the second end, thereby reducing damage to the water-repellent film. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a printer according to an embodiment and a modification, seen from above. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an inkjet head. [Figure 3] Fig. 3A is a cross-sectional view showing a part of an inkjet head, and Fig. 3B is a diagram showing a discharge surface, nozzle holes provided on the discharge surface, and a water-repellent film provided around the nozzle holes. [Figure 4] FIG. 4 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 1, and a water-repellent film provided around the nozzle holes. [Figure 5] FIG. 5 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 2, and a water-repellent film provided around the nozzle holes. [Figure 6] FIG. 6 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to another modified example of Modification Example 2, and a water-repellent film provided around the nozzle holes. [Figure 7] FIG. 7 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 3, and a water-repellent film provided around the nozzle holes. [Figure 8]Fig. 8A is a diagram schematically showing nozzle holes provided in the ejection surface of an inkjet head according to Modification 4, and a water-repellent film provided around the nozzle holes. Fig. 8B is a cross-sectional view schematically showing a part of the inkjet head of Fig. 8A. [Figure 9] FIG. 9 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 5, and a water-repellent film provided around the nozzle holes. [Figure 10] FIG. 10 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 6, and a water-repellent film provided around the nozzle holes. [Figure 11] FIG. 11 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 7, and a water-repellent film provided around the nozzle holes. [Figure 12] FIG. 12 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to Modification 9, and a water-repellent film provided around the nozzle holes. [Figure 13] FIG. 13 is a diagram schematically showing nozzle holes provided on the ejection surface of an inkjet head according to another modified example of the ninth modified example, and a water-repellent film provided around the nozzle holes. [Figure 14] Fig. 14A is a cross-sectional view schematically showing a part of an inkjet head according to Modification 10. Fig. 14B is a view schematically showing nozzle holes provided in the ejection surface of the inkjet head and a water-repellent film provided around the nozzle holes. [Figure 15] FIG. 15 is a cross-sectional view schematically showing a part of an ink-jet head according to an eleventh modification. [Figure 16] FIG. 16 is a cross-sectional view schematically showing an ink-jet head according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Printer> 1, a printer 10 according to an embodiment of the present disclosure is an inkjet printer that ejects ink from nozzles 21 of an inkjet head (hereinafter referred to as "head") 20 onto a print medium P to print an image on the print medium P. The print medium P is, for example, a sheet of paper, cloth, or the like.

[0012] The printer 10 is a serial head type printer and includes a head 20, a platen 11, a tank 12, a housing 13, a transport device 30, a moving device 40, a control device 14, and a maintenance device 50. The moving device 40 has a carriage 41 that carries the head 20. In the following, the direction in which the carriage 41 moves will be referred to as the left-right direction. A direction that intersects (e.g., is perpendicular to) the direction of movement of the carriage 41 and in which the print medium P is transported by the transport device 30 will be referred to as the front-rear direction. A direction that intersects (e.g., is perpendicular to) the direction of movement of the carriage 41 and the transport direction of the print medium P will be referred to as the up-down direction. However, the directions related to the printer 10 are not limited to these.

[0013] The housing 13 houses the head 20, the platen 11, the tank 12, the transport device 30, the moving device 40, the control device 14, and the maintenance device 50. The housing 13 also has a printing area 13a in which the platen 11 is disposed, and a maintenance area 13b in which the maintenance device 50 is disposed. In the example of FIG. 1, the maintenance area 13b is disposed to the left of the printing area 13a. The platen 11 is disposed below the head 20 at a predetermined distance. The flat upper surface of the platen 11 is disposed opposite the ejection surface 24a, which is the lower surface of the head 20, and supports the print medium P from below.

[0014] The head 20 has a plurality of nozzles 21 and a plurality of drive elements 23 (FIG. 2). The plurality of nozzles 21 are aligned in the front-to-rear direction to form a nozzle row 29, and the plurality of nozzle rows 29 (four in the example of FIG. 1) are aligned at intervals in the left-to-right direction. The nozzles 21 open to the ejection surface 24a of the head 20, and a water-repellent film 60 is provided around the nozzle holes 22 at the tips of the nozzles 21. The drive elements 23 are piezoelectric elements provided for each nozzle 21, and apply pressure to the ink in the head 20 to eject ink from the nozzle holes 22. Note that the drive elements 23 are not limited to piezoelectric elements, and may be heat-generating elements, electrostatic actuators, or the like. Note that the head 20 will be described in detail later.

[0015] The tanks 12 are containers that store ink to be supplied to the head 20. The multiple tanks 12 store, for example, different types of ink, such as cyan ink, magenta ink, yellow ink, and black ink, respectively. Each tank 12 is connected to the head 20 by a flexible tube. The ink from the tank 12 is sent to the head 20 through the tube.

[0016] The transport device 30 includes, for example, a transport roller 31 and a transport motor. The transport roller 31 has a shaft extending in the left-right direction, and the transport motor is connected to the shaft of the transport roller 31. When the transport motor is driven to rotate, the transport roller 31 rotates around its shaft, transporting the print medium P on the platen 11 in the front-to-rear direction.

[0017] The moving device 40 has a carriage 41, two guide rails 42, an endless belt 43, and a moving motor 44. The carriage 41 is box-shaped and carries the head 20. The two guide rails 42 extend laterally across the platen 11 located directly below it, and are spaced apart from each other in the front and rear with all of the nozzles 21 sandwiched between them, movably supporting the carriage 41. The endless belt 43 is connected to the carriage 41 and is also connected to the moving motor 44 via a pulley 45 provided on the guide rails 42. Therefore, when the moving motor 44 is driven to rotate, the endless belt 43 runs, and the carriage 41 and the head 20 supported by the carriage 41 are moved left and right along the guide rails 42 across the printing area 13a and the maintenance area 13b.

[0018] The maintenance device 50 has a wiper 51, a waste liquid container 52, and a displacement device 53 that displaces the wiper 51. The wiper 51 is, for example, flat and has a dimension longer than the dimension of the nozzle row 29 of the head 20 in the front-to-rear direction, and is disposed in a position overlapping the nozzle row 29 when viewed from the right. The wiper 51 is also disposed below the ejection surface 24a of the head 20 in the up-down direction.

[0019] The displacement device 53 displaces the wiper 51 between a close position where the wiper 51 contacts at least one of the ejection surface 24a and the water-repellent film 60, and a separated position where the wiper 51 is separated from the ejection surface 24a and the water-repellent film 60. For example, the displacement device 53 raises the wiper 51 from the separated position to the close position during maintenance operations, and lowers the wiper 51 from the close position to the separated position during printing operations. The waste liquid container 52 has a box shape with an open top. The lower part of the wiper 51 is inserted into the waste liquid container 52 through the upper opening so that ink removed from the ejection surface 24a by the wiper 51 flows into the waste liquid container 52.

[0020] The control device 14 is a computer and has an arithmetic processing unit and a storage unit. The storage unit is memory accessible from the arithmetic processing unit, such as RAM and ROM, and stores programs and data used therein. The arithmetic processing unit is a processor such as a CPU, and by executing this program, the control device 14 controls the operation of each part of the printer 10 and performs operations of the printer 10, such as printing operations and maintenance operations. The control device 14 may be configured as a single device, or may be configured as multiple devices distributed in a distributed arrangement that work together to perform the operations of the control device 14.

[0021] <Printing operation> The control device 14 ejects ink from the head 20 onto the print medium P while moving the carriage 41 carrying the head 20 to the right or left. The control device 14 also transports the print medium P forward. In this way, the printer 10 alternates between operations including moving the head 20 and ejecting ink and transporting the print medium P to proceed with the printing operation.

[0022] <Maintenance operation> The control device 14 moves the head 20 using the carriage 41 while the wiper 51 is positioned at the close position using the displacement device 53. As a result, at least one of the ejection surface 24a of the head 20 and the water-repellent film 60 on the ejection surface 24a moves left or right relative to the wiper 51 while in contact with the wiper 51. As a result, the ink on the ejection surface 24a and the water-repellent film 60 is removed by the wiper 51, flows down the wiper 51, and flows into the waste liquid container 52 where it is stored. This makes it possible to suppress staining of the print medium P caused by the ink on the ejection surface 24a and the water-repellent film 60, and suppress poor ink ejection from the nozzle holes 22 of the ejection surface 24a.

[0023] <head> As shown in the example of FIG. 2, the head 20 includes a flow path forming body, a water-repellent film 60, and a driving element 23. The flow path forming body is, for example, a laminated body in which multiple plates are stacked, and includes a nozzle plate 24, multiple flow path plates 25, and a vibration plate 26. These plates are rectangular flat plates, stacked in this order, and bonded to each other with an adhesive or the like. For example, the nozzle plate 24 is made of a resin such as polyimide resin, and the flow path plate 25 is made of a metal such as SUS. Note that, hereinafter, the stacking direction in which the flow path plates 25 are stacked on the nozzle plate 24 may be referred to as the up-down direction. The water-repellent film 60 will be described later.

[0024] Each plate has through-holes that penetrate the plate and recesses that are recessed from the top or bottom surface of the plate. For example, the through-holes and recesses are formed by etching the plates. Inside the flow path forming body where the plates are stacked, the through-holes and recesses are combined to provide a plurality of nozzles 21, a plurality of individual channels 27, and a supply manifold 28 to which these are connected.

[0025] The plurality of nozzles 21 are provided in a nozzle plate 24. The nozzles 21 penetrate the nozzle plate 24 in the vertical direction and open to a discharge surface 24a of the nozzle plate 24, and nozzle holes 22 are provided in the discharge surface 24a. The nozzle 21 has, for example, an axis extending in the vertical direction, a nozzle hole 22 which is a circular tip, and a circular base end, and is in the shape of a truncated cone with the diameter of the nozzle hole 22 being smaller than the diameter of the base end.

[0026] The supply manifold 28 extends in the front-rear direction and is connected to the tank 12 (FIG. 1). Each individual channel 27 has a supply orifice 27a, a pressure chamber 27b, and a descender 27c, which are connected in this order. Of the individual channel 27, the supply orifice 27a is connected to the supply manifold 28, and the descender 27c is connected to the nozzle 21.

[0027] The supply restrictor 27a is connected to the supply manifold 28 and the pressure chamber 27b. The cross-sectional area of ​​the supply restrictor 27a perpendicular to the ink flow direction is smaller than that of the supply manifold 28 and the pressure chamber 27b. The upper end opening of the pressure chamber 27b is covered by the vibration plate 26. The descender 27c is shaped like a column, such as a cylinder or a rectangular pillar, and is provided coaxially with the nozzle 21. It extends in the vertical direction and has a first end 27c1 connected to the pressure chamber 27b and a second end 27c2 connected to the base end of the nozzle 21.

[0028] The driving element 23 is disposed on the vibration plate 26 so as to overlap the pressure chamber 27b when viewed from above, and expands and contracts upon receiving a control signal from the control device 14 (FIG. 1). As a result, the vibration plate 26 between the driving element 23 and the pressure chamber 27b deforms in cooperation with the driving element 23, and changes in the direction of increasing or decreasing the volume of the pressure chamber 27b. Therefore, pressure for ejecting ink from the nozzle orifice 22 is applied to the ink in the pressure chamber 27b, and ink is ejected from the nozzle orifice 22 that communicates with the pressure chamber 27b.

[0029] The multiple flow path plates 25 in the head 20 of the example shown in FIG. 2 include a first flow path plate 25a to a fourth flow path plate 25d, which are descender plates in which descenders 27c are formed, and a fifth flow path plate 25e, which is a pressure chamber plate in which pressure chambers 27b are formed. The nozzle plate 24 and the first flow path plates 25a to 25e are stacked in this order along the vertical direction. As a result, the descender plates are stacked between the nozzle plate 24 and the pressure chamber plates. Of these, a second end 27c2 of the descender 27c is provided on the first flow path plate 25a, and a first end 27c1 of the descender 27c is provided on the fourth flow path plate 25d. The lower surface of the first flow path plate 25a faces the upper surface of the nozzle plate 24, and the second end 27c2 opening on the lower surface of the first flow path plate 25a is connected to the base end of the nozzle 21 opening on the upper surface of the nozzle plate 24.

[0030] The diameter B of the second end 27c2 of the descender 27c connected to the base end of the nozzle 21 is larger than the diameter A of the nozzle hole 22 and the diameter of the base end of the nozzle 21. For example, the diameter A of the nozzle hole 22 is 15 μm, and the diameter B of the second end 27c2 is 100 μm. The edge of the second end 27c2 surrounds the periphery of the base end of the nozzle 21, and the upper surface of the nozzle plate 24 covers the second end 27c2 between the edge of the second end 27c2 and the base end of the nozzle 21. As a result, the nozzle plate 24 comes into contact with the ink of the descender 27c between the edge of the second end 27c2 and the base end of the nozzle 21, and also comes into contact with the ink of the nozzle 21 inside the edge of the base end of the nozzle 21.

[0031] <Water-repellent film> As shown in the examples of FIGS. 3A and 3B, the head 20 is provided with a water-repellent film 60 around the nozzle holes 22 that open in the ejection surface 24a of the nozzle plate 24. The water-repellent film 60 covers the ejection surface 24a around the nozzle holes 22. In the vertical direction, the thickness C of the water-repellent film 60 is much thinner than the thickness D of the nozzle plate 24. For example, the thickness C of the water-repellent film 60 is 20 nm or more and 100 nm or less, and the thickness D of the nozzle plate 24 is 50 μm. This keeps the step of the water-repellent film 60 relative to the ejection surface 24a small, reducing the risk of the wiper 51 getting caught on the step and damaging the water-repellent film 60.

[0032] The water-repellent film 60 has greater water repellency than the ejection surface 24a of the nozzle plate 24, and is formed from, for example, a resin containing monomolecular fluorine, a fluororesin, or a silicone resin. Therefore, even if ink ejected from the nozzle holes 22 scatters around the nozzle holes 22, the ink adheres to the water-repellent film 60. Therefore, the ink on the water-repellent film 60 can be easily removed from the periphery of the nozzle holes 22 by the wiper 51, thereby reducing poor ink ejection from the nozzle holes 22 caused by ink adhering around the periphery of the nozzle holes 22.

[0033] The water-repellent film 60 may have a hardness higher than that of the nozzle plate 24. In this case, the water-repellent film 60 may be formed of a single layer in which a water-repellent component such as fluorine is contained in an inorganic material such as SiO2 or an organic material. Alternatively, the water-repellent film 60 may be formed of multiple layers in which a water-repellent layer containing a water-repellent component is laminated on the surface of an inorganic or organic layer. By covering the ejection surface 24a with such a water-repellent film 60 with high hardness, it is possible to reduce damage to the ejection surface 24a, such as scratches caused by the wiper 51.

[0034] The water-repellent film 60 is, for example, annular, and has a circular inner peripheral edge 61 and a circular outer peripheral edge 62 that surrounds the inner peripheral edge 61. Hereinafter, the radial direction of the nozzle hole 22 may be referred to as the radial direction, and the circumferential direction of the nozzle hole 22 may be referred to as the circumferential direction. In addition, the side of the inner peripheral edge 61 closer to the outer peripheral edge 62 in the radial direction may be referred to as the inner side, and the opposite side may be referred to as the outer side.

[0035] The diameter E of the inner peripheral edge 61 of the water-repellent film 60 is equal to the diameter A of the nozzle hole 22, and when viewed in the vertical direction, the inner peripheral edge 61 of the water-repellent film 60 overlaps with the edge of the nozzle hole 22. As a result, the water-repellent film 60 covers the edge of the nozzle hole 22 and spreads out in the radial direction from the edge of the nozzle hole 22. As a result, the water-repellent film 60 covers the edge of the nozzle hole 22 and the ejection surface 24a around it, thereby reducing poor ejection of ink from the nozzle hole 22 and damage to the ejection surface 24a by the wiper 51.

[0036] The outer peripheral edge 62 of the water-repellent film 60 is located between the inner peripheral edge 61 and the edge of the second end 27c2 of the descender 27c when viewed in the up-down direction, and is arranged so as to share a center with the inner peripheral edge 61. Therefore, the dimension G between the outer peripheral edge 62 and the inner peripheral edge 61 in the radial direction is constant in the circumferential direction and is larger than a predetermined dimension H. This predetermined dimension H is equal to or larger than the diameter of the nozzle hole 22, and therefore the dimension G between the outer peripheral edge 62 and the inner peripheral edge 61 is also equal to or larger than the diameter of the nozzle hole 22. Furthermore, the diameter F of the water-repellent film 60 is greater than three times the diameter A of the nozzle hole 22.

[0037] The water-repellent film 60 has an inner film region 63, which is a region that is a predetermined dimension H or less from the inner peripheral edge 61 along the radial direction. The dimension of the inner film region 63 in the radial direction is the predetermined dimension H, for example, equal to or greater than the diameter of the nozzle hole 22. Because the periphery of the nozzle hole 22 is covered by this inner film region 63, even if ink splashes when it is ejected from the nozzle hole 22, the splashed ink adheres to the inner film region 63 of the water-repellent film 60. Therefore, the splashed ink is prevented from diffusing around the nozzle hole 22, thereby reducing ink ejection defects caused by the splashed ink.

[0038] The water-repellent film 60 has a lower hygroscopicity than the nozzle plate 24. Therefore, when the nozzle plate 24 and the water-repellent film 60 are in contact with ink for a long period of time, the nozzle plate 24 swells more than the water-repellent film 60 due to the ink. This swelling of the nozzle plate 24 generates stress in the water-repellent film 60, which may cause the water-repellent film 60 to peel off from the ejection surface 24a of the nozzle plate 24, crack the water-repellent film 60, or otherwise damage the water-repellent film 60. In response to this, the water-repellent film 60 is not provided in the outer region I, which is the region outside the edge of the second end 27c2, as viewed in the up-down direction, but is provided in the inner film region J, which is the region inside the edge of the second end 27c2, thereby reducing damage to the water-repellent film 60.

[0039] That is, as described above, the nozzle plate 24 is in contact with ink in the inner film region J that is inside the edge of the second end 27c2. In contrast, the outer region I of the nozzle plate 24 that is outside the edge of the second end 27c2 is stacked on the flow path plate 25 and is not in contact with ink. For this reason, swelling of the nozzle plate 24 by ink is greater in the inner film region J than in the outer region I.

[0040] In contrast, the outer peripheral edge 62 of the water-repellent film 60 is disposed between the inner peripheral edge 61 of the water-repellent film 60 and the edge of the second end 27c2 when viewed in the up-down direction. Therefore, the water-repellent film 60 is not provided in the outer region I but is provided in the inner film region J. The difference in the swelling amount of the nozzle plate 24 in the region where the water-repellent film 60 is provided is smaller when the water-repellent film 60 is not provided in the outer region I but is provided in the inner film region J than when the water-repellent film 60 is provided across both the outer region I and the inner film region J. Therefore, the stress caused by the swelling of the nozzle plate 24 is smaller when the water-repellent film 60 is not provided in the outer region I but is provided in the inner film region J than when the water-repellent film 60 is provided across both the outer region I and the inner film region J. Therefore, the stress on the water-repellent film 60 due to the swelling of the nozzle plate 24 can be kept small, and damage to the water-repellent film 60 can be reduced.

[0041] <Variation 1> 4, in the head 20 according to the first modification, in the above embodiment, the water-repellent film 60 is provided with a stress relaxation portion at a position greater than a predetermined distance H from the inner circumferential edge 61 along the radial direction of the nozzle hole 22, the stress relaxation portion having a lower mechanical strength than a portion at a position equal to or less than the predetermined distance H from the inner circumferential edge 61. For example, the stress relaxation portion may be an annular notch 65 surrounding the nozzle hole 22 at a position greater than the predetermined distance H from the inner circumferential edge 61 along the radial direction of the nozzle hole 22.

[0042] Specifically, the water-repellent film 60 has, inside its outer peripheral edge 62, an annular notch 65 where no film is formed, and a first film-forming region other than the annular notch 65 where a film is formed. The annular notch 65 has an annular shape, such as a circular ring, and is disposed between the inner peripheral edge 61 and the outer peripheral edge 62 of the water-repellent film 60 so as to share a center with the inner peripheral edge 61 and the outer peripheral edge 62. The dimension between the annular notch 65 and the inner peripheral edge 61 along the radial direction is greater than a predetermined dimension H, and the annular notch 65 is disposed radially outward of an inner film region 63 that is equal to or less than the predetermined dimension H from the inner peripheral edge 61. In other words, the annular notch 65 is disposed radially at a position greater than the predetermined dimension H from the inner peripheral edge 61.

[0043] As a result, the annular notch 65 is not provided in the inner film region 63, and the inner film region 63 is a first film formation region that covers the periphery of the nozzle hole 22. Therefore, the scattered ink from the nozzle hole 22 adheres to the inner film region 63 without being diffused by the annular notch 65, thereby suppressing the diffusion of ink around the nozzle hole 22. This makes it possible to reduce ink ejection defects caused by diffused ink around the nozzle hole 22.

[0044] The water-repellent film 60 is divided into an annular inner portion 60c located inside the annular cutout 65 and an annular outer portion 60d located outside the annular cutout 65. The inner portion 60c and the outer portion 60d deform or move independently of each other so that the width of the annular cutout 65 between them narrows or widens, thereby deforming the water-repellent film 60 at the annular cutout 65. For this reason, the mechanical strength of the annular cutout 65 in the water-repellent film 60 is lower than the mechanical strength of portions of the water-repellent film 60 other than the annular cutout 65 (for example, the inner film region 63). As a result, even if stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 by ink, the water-repellent film 60 deforms at the annular cutout 65. Therefore, the stress on the water-repellent film 60 due to swelling of the nozzle plate 24 is reduced (alleviated) compared to the stress on the water-repellent film 60 without the annular notch 65, and damage to the water-repellent film 60 can be reduced.

[0045] <Variation 2> In the head 20 according to the second modification, in the above embodiment, a stress relief portion is provided in the water-repellent film 60, as shown in the example of Fig. 5. For example, the stress relief portion may be a linear notch 66 that extends from a position that is greater than a predetermined dimension H from the inner peripheral edge 61 along the radial direction of the nozzle hole 22 toward the outer peripheral edge 62 along the radial direction of the nozzle hole 22.

[0046] Specifically, the water-repellent film 60 has, inside its outer peripheral edge 62, linear notches 66 where no film is formed, and a second film-forming region which is a region other than the linear notches 66 and where a film is formed. One or more linear notches 66 (four in the example of FIG. 5) are provided in the water-repellent film 60. The linear notches 66 are straight and extend continuously from the outer peripheral edge 62 of the water-repellent film 60 toward the inner peripheral edge 61 in the radial direction.

[0047] For example, four linear notches 66 are arranged at equal intervals in the circumferential direction. Of these, the linear notch 66 in front of the inner peripheral edge 61 extends rearward from the front end of the outer peripheral edge 62 of the water-repellent film 60, and the linear notch 66 behind the inner peripheral edge 61 extends forward from the rear end of the outer peripheral edge 62 of the water-repellent film 60. In addition, the linear notch 66 to the left of the inner peripheral edge 61 extends rightward from the left end of the outer peripheral edge 62 of the water-repellent film 60, and the linear notch 66 to the right of the inner peripheral edge 61 extends leftward from the right end of the outer peripheral edge 62 of the water-repellent film 60.

[0048] The dimension between the inner circumferential edge 61 and the end of the linear notch 66 closest to the inner circumferential edge 61 in the radial direction is larger than a predetermined dimension H, and the linear notch 66 is provided outside the inner film region 63. As a result, the linear notch 66 is not provided in the inner film region 63, and the inner film region 63 is a second film formation region that covers the periphery of the nozzle hole 22. Therefore, the scattered ink from the nozzle hole 22 adheres to the inner film region 63 without being diffused by the linear notch 66, thereby suppressing the diffusion of ink around the nozzle hole 22. This makes it possible to reduce ink ejection defects caused by diffused ink around the nozzle hole 22.

[0049] In addition to an inner peripheral edge 61 and an outer peripheral edge 62, the water-repellent film 60 has a forming edge that is an edge that forms a linear notch 66. This forming edge has a pair of second side forming edges 66a that sandwich the linear notch 66 between them in the circumferential direction, and a second inner forming edge 66b that is connected to both of the pair of second side forming edges 66a. One end of the second side forming edge 66a is connected to the outer peripheral edge 62, and the other end is connected to the second inner forming edge 66b. Unlike the outer peripheral edge 62, the second side forming edge 66a and the second inner forming edge 66b that form this linear notch 66 are positioned closer to the inner peripheral edge 61 in the radial direction than the outer peripheral edge 62.

[0050] The water-repellent film 60 is deformed at the linear notches 66 so that the width of the linear notches 66 between the pair of second-side forming edges 66a becomes narrower or wider. Therefore, the mechanical strength of the linear notches 66 in the water-repellent film 60 is lower than the mechanical strength of portions of the water-repellent film 60 other than the linear notches 66 (for example, the inner film region 63). As a result, even when stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 by ink, the water-repellent film 60 is deformed at the linear notches 66. Therefore, the stress in the water-repellent film 60 due to swelling of the nozzle plate 24 is reduced (alleviated) compared to the stress in a water-repellent film 60 without the linear notches 66, and damage to the water-repellent film 60 can be reduced.

[0051] 6, the linear notch 66 serving as the stress relaxation portion may be provided outside the first overlapping region 71 that overlaps with the nozzle hole 22 when viewed along the relative movement direction of the wiper 51 with respect to the ejection surface 24a. Hereinafter, the relative movement direction of the wiper 51 with respect to the ejection surface 24a may be referred to as the left-right direction.

[0052] Specifically, the first overlapping region 71 is a region that overlaps with the nozzle hole 22 when viewed, for example, in the left-right direction, and extends in the left-right direction from the nozzle hole 22. The first overlapping region 71 is a region between a straight line 71a that passes through the front end of the nozzle hole 22 and extends in the left-right direction, and a straight line 71b that passes through the rear end of the nozzle hole 22 and extends in the left-right direction.

[0053] In contrast, the water-repellent film 60 is provided with a first overlapping region 71 and one or more (two in the example of FIG. 6 ) linear notches 66. Of these linear notches 66, the front linear notch 66 extends rearward from the front end of the outer circumferential edge 62 of the water-repellent film 60, and the rear linear notch 66 extends forward from the rear end of the outer circumferential edge 62 of the water-repellent film 60. In the front-to-rear direction, the front linear notch 66 is located forward of the inner circumferential edge 61, and the rear linear notch 66 is located rearward of the inner circumferential edge 61. This inner circumferential edge 61 overlaps with the edge of the nozzle hole 22. For this reason, these linear notches 66 are located forward or rearward of the first overlapping region 71 of the nozzle hole 22.

[0054] In this way, the linear notch 66 is provided outside the first overlapping region 71 of the nozzle hole 22, and the first overlapping region 71 is the second film formation region. As a result, even when the wiper 51 moves relatively in the left-right direction with respect to the ejection surface 24a while contacting the ejection surface 24a and the water-repellent film 60, the ink removed from the nozzle hole 22 by the wiper 51 passes through the first overlapping region 71, and therefore is less likely to enter the linear notch 66. Therefore, it is possible to reduce staining of the print medium P caused by ink in the linear notch 66 and poor ink ejection.

[0055] Furthermore, as shown in the example of Figure 6, the linear notch 66, which is a stress relief portion, may be provided outside the second overlapping region 72 that overlaps with the nozzle hole surrounding region 75 that is a predetermined dimension H or less from the edge of the nozzle hole 22 along the radial direction of the nozzle hole 22 and is viewed along the relative movement direction of the wiper 51 with respect to the ejection surface 24a.

[0056] Specifically, the nozzle hole surrounding region 75 has an annular shape, such as a circular ring, and is a region from the edge of the nozzle hole 22 to a position of a predetermined dimension H in the radial direction. The second overlapping region 72 is a region that overlaps with the nozzle hole surrounding region 75 when viewed, for example, in the left-right direction. The second overlapping region 72 is a region between a straight line 72a that passes through the front end of the nozzle hole surrounding region 75 and extends in the left-right direction, and a straight line 72b that passes through the rear end of the nozzle hole surrounding region 75 and extends in the left-right direction. The second overlapping region 72 is a region that is equal to or smaller than the predetermined dimension H from the edge of the nozzle hole 22 in the front-back direction.

[0057] 6, the water-repellent film 60 is provided with a second overlapping region 72 and two linear cutouts 66. In the front-to-rear direction, the dimension between the rear end of the linear cutout 66 in front of the inner circumferential edge 61 and the inner circumferential edge 61, and the dimension between the front end of the linear cutout 66 behind the inner circumferential edge 61 and the inner circumferential edge 61 are greater than a predetermined dimension H. This inner circumferential edge 61 overlaps with the nozzle hole 22. As a result, the linear cutout 66 is provided in front of or behind a nozzle hole surrounding region 75 that is the predetermined dimension H or less from the edge of the nozzle hole 22, and the second overlapping region 72 of the nozzle hole surrounding region 75.

[0058] In this way, since the linear notch 66 is provided outside the second overlapping region 72 of the nozzle hole surrounding region 75, the second overlapping region 72 is the second film formation region. As a result, even when ink scattered from the nozzle holes 22 adheres to the water-repellent film 60 in the nozzle hole surrounding region 75 and the wiper 51 moves relatively in the left-right direction with respect to the ejection surface 24a while contacting the ejection surface 24a and the water-repellent film 60, the ink removed from the water-repellent film 60 in the nozzle hole surrounding region 75 by the wiper 51 passes through the second overlapping region 72, and therefore is less likely to enter the linear notch 66. Therefore, it is possible to reduce staining of the print medium P and poor ink ejection caused by ink in the linear notch 66.

[0059] <Variation 3> In the head 20 according to the third modification, in the above embodiment, stress relief portions are provided in the water-repellent film 60. For example, as shown in Fig. 7, the stress relief portions may be dashed-line notches 67 provided in parallel to each other, sandwiching the nozzle hole 22 between them, at positions greater than a predetermined distance H from the inner circumferential edge 61 along the radial direction of the nozzle hole 22.

[0060] Specifically, the water-repellent film 60 has, inside its outer peripheral edge 62, a broken-line cutout 67 having a cutout portion 67a where no film is formed, and a third film-forming region which is a region other than the broken-line cutout 67 and where a film is formed. Two broken-line cutouts 67 are provided in the water-repellent film 60. The dimension between the broken-line cutout 67 and the inner peripheral edge 61 in the radial direction is larger than a predetermined dimension H, and the broken-line cutout 67 is provided outside the inner film region 63. In other words, the two broken-line cutouts 67 sandwich the nozzle hole 22 between them in the front-to-rear direction, and are located at a position larger than the predetermined dimension H from the inner peripheral edge 61 along the radial direction of the nozzle hole 22.

[0061] As a result, the dashed notch 67 is not provided in the inner film region 63, and the inner film region 63 is a third film formation region that covers the periphery of the nozzle hole 22. Therefore, the ink scattered from the nozzle hole 22 adheres to the inner film region 63 without being diffused by the dashed notch 67, which suppresses the diffusion of ink around the nozzle hole 22, thereby reducing ink ejection defects caused by diffused ink around the nozzle hole 22.

[0062] The broken-line cutout 67 is configured with a plurality of cutout portions 67a arranged in a row at intervals in the left-right direction, and extends across the water-repellent film 60 in the left-right direction. In the water-repellent film 60, the mechanical strength of the broken-line cutout 67 is lower than the mechanical strength of portions other than the broken-line cutout 67 (for example, the inner film region 63). As a result, even if stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 by ink, the water-repellent film 60 will be damaged at the broken-line cutout 67. Therefore, the stress in the water-repellent film 60 due to swelling of the nozzle plate 24 is reduced (alleviated) compared to the stress in a water-repellent film 60 without the broken-line cutout 67, and damage to the water-repellent film 60 can be reduced.

[0063] Furthermore, of the two broken-line cutouts 67, the front broken-line cutout 67 is located forward of the inner peripheral edge 61, and the rear broken-line cutout 67 is located rearward of the inner peripheral edge 61. In the front-to-rear direction, the distance between the front broken-line cutout 67 and the inner peripheral edge 61 and the distance between the rear broken-line cutout 67 and the inner peripheral edge 61 are equal to each other. This makes the two broken-line cutouts 67 equally susceptible to damage, making it possible to more uniformly reduce damage to the water-repellent film 60 due to swelling of the nozzle plate 24.

[0064] The dashed notches 67, which are stress relief portions, may extend along the direction of relative movement of the wiper 51 with respect to the ejection surface 24a. In the front-to-rear direction, which is perpendicular to this direction of relative movement, the dimension of the wiper 51 is greater than the dimension between the two dashed notches 67. As a result, when the wiper 51 moves while contacting the water-repellent film 60 on the ejection surface 24a, the wiper 51 moves along the dashed notches 67, making it easier to remove ink from the dashed notches 67. This makes it possible to reduce stains on the print medium P and ink ejection defects caused by ink in the dashed notches 67.

[0065] Furthermore, the dashed-line cutout 67 is provided in front of or behind the nozzle hole 22 and its first overlapping region 71, and is therefore provided outside the first overlapping region 71 of the nozzle hole 22. As a result, the first overlapping region 71 is a third film-forming region. Therefore, even when the wiper 51 moves relatively in the left-right direction with respect to the ejection surface 24a while contacting the ejection surface 24a and the water-repellent film 60, the ink removed from the nozzle hole 22 by the wiper 51 is reduced from passing through the first overlapping region 71 and entering the dashed-line cutout 67. This reduces staining of the print medium P and poor ink ejection caused by ink in the dashed-line cutout 67.

[0066] Furthermore, in the front-to-rear direction, the dimension between the inner peripheral edge 61 and the rear end of the broken-line cutout 67 forward of the inner peripheral edge 61, and the dimension between the inner peripheral edge 61 and the front end of the broken-line cutout 67 rearward of the inner peripheral edge 61, are larger by a predetermined dimension H. This inner peripheral edge 61 overlaps with the nozzle hole 22. As a result, the broken-line cutout 67 is provided forward or rearward of the nozzle hole surrounding region 75, which is the predetermined dimension H or less from the edge of the nozzle hole 22, and the second overlapping region 72 of the nozzle hole surrounding region 75.

[0067] In this way, the dashed-line notch 67 is provided outside the second overlapping region 72 in the nozzle hole surrounding region 75, and the second overlapping region 72 is the third film-forming region. As a result, even when ink scattered from the nozzle holes 22 adheres to the water-repellent film 60 in the nozzle hole surrounding region 75 and the wiper 51 moves relatively in the left-right direction with respect to the ejection surface 24a while contacting the water-repellent film 60 on the ejection surface 24a, the ink removed from the water-repellent film 60 in the nozzle hole surrounding region 75 by the wiper 51 passes through the second overlapping region 72, and therefore is less likely to enter the dashed-line notch 67. This makes it possible to reduce staining of the print medium P and poor ink ejection caused by the ink in the dashed-line notch 67.

[0068] <Variation 4> In the head 20 according to the fourth modification, in the above embodiment, a stress relief portion is provided in the water-repellent film 60. For example, as shown in Figures 8A and 8B, the stress relief portion may have grooves 68 provided parallel to each other with the nozzle hole 22 sandwiched between them, at a position greater than a predetermined distance H from the inner circumferential edge 61 along the radial direction of the nozzle hole 22.

[0069] Specifically, the water-repellent film 60 has, inside its outer circumferential edge 62, grooves 68 with a thin film thickness, and a fourth film-forming region other than the grooves 68 with a thicker film thickness than the grooves 68. Two grooves 68 are provided in the water-repellent film 60. The grooves 68 are recessed from the upper surface of the water-repellent film 60. The dimension between the grooves 68 and the inner circumferential edge 61 in the radial direction is larger than a predetermined dimension H, and the grooves 68 are provided outside the inner film region 63.

[0070] As a result, the grooves 68 are not provided in the inner film region 63, and the inner film region 63 is a fourth film formation region that covers the periphery of the nozzle hole 22. Therefore, ink scattered from the nozzle hole 22 is less likely to accumulate in the grooves 68, and adheres to the inner film region 63. This makes it possible to reduce ink ejection defects caused by ink accumulating in the grooves 68 around the nozzle hole 22.

[0071] The grooves 68 extend in the left-right direction across the water-repellent film 60. In the up-down direction, the dimension (thickness) K of the water-repellent film 60 at the grooves 68 is smaller than the dimension (thickness) C at portions other than the grooves 68. Therefore, in the water-repellent film 60, the mechanical strength of the grooves 68 is lower than the mechanical strength of portions other than the grooves 68 (for example, the inner film region 63). As a result, even if stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 by ink, the water-repellent film 60 will be damaged at the grooves 68. Therefore, the stress in the water-repellent film 60 due to swelling of the nozzle plate 24 is reduced (alleviated) compared to the stress in a water-repellent film 60 without the grooves 68, and damage to the water-repellent film 60 can be reduced.

[0072] Furthermore, of the two grooves 68, the front groove 68 is disposed forward of the inner circumferential edge 61, and the rear groove 68 is disposed rearward of the inner circumferential edge 61. In other words, the two grooves 68 sandwich the nozzle hole 22 in the front-to-rear direction, and are located at a distance greater than a predetermined distance H from the inner circumferential edge 61 along the radial direction of the nozzle hole 22. In the front-to-rear direction, the distance between the front groove 68 and the inner circumferential edge 61 and the distance between the rear groove 68 and the inner circumferential edge 61 are equal to each other. This makes the two grooves 68 equally susceptible to damage, making it possible to more uniformly reduce damage to the water-repellent film 60 due to swelling of the nozzle plate 24.

[0073] The grooves 68, which are stress relief portions, may extend along the direction of relative movement of the wiper 51 with respect to the ejection surface 24a. In the front-to-rear direction, which is perpendicular to this direction of relative movement, the dimension of the wiper 51 is greater than the dimension between the two grooves 68. As a result, when the wiper 51 moves relative to the ejection surface 24a while contacting the water-repellent film 60 on the ejection surface 24a, the wiper 51 moves along the grooves 68, making it easier to remove ink from the grooves 68. This makes it possible to reduce staining of the print medium P and ink ejection defects caused by ink in the grooves 68.

[0074] Furthermore, the groove 68 is provided in front of or behind the nozzle hole 22 and its first overlapping region 71, and is therefore provided outside the first overlapping region 71 of the nozzle hole 22. As a result, the first overlapping region 71 is a fourth film formation region. Therefore, even when the wiper 51 moves relatively in the left-right direction with respect to the ejection surface 24a while contacting the ejection surface 24a and the water-repellent film 60, the ink removed from the nozzle hole 22 by the wiper 51 is reduced from entering the groove 68 through the first overlapping region 71, thereby reducing staining of the print medium P and poor ink ejection caused by the ink in the groove 68.

[0075] Furthermore, in the front-to-rear direction, the dimension between the rear end of the groove 68 forward of the inner circumferential edge 61 and the inner circumferential edge 61, and the dimension between the front end of the groove 68 rearward of the inner circumferential edge 61 and the inner circumferential edge 61 are larger by a predetermined dimension H. This inner circumferential edge 61 overlaps with the nozzle hole 22. As a result, the groove 68 is provided forward or rearward of a nozzle hole surrounding region 75, which is the predetermined dimension H or less from the edge of the nozzle hole 22, and a second overlapping region 72 of the nozzle hole surrounding region 75.

[0076] In this way, the groove 68 is provided outside the second overlapping region 72, which is the fourth film-forming region. As a result, even when ink scattered from the nozzle holes 22 adheres to the water-repellent film 60 in the nozzle hole peripheral region 75 and the wiper 51 moves relatively in the left-right direction with respect to the ejection surface 24a while contacting the water-repellent film 60 on the ejection surface 24a, the ink removed from the water-repellent film 60 in the nozzle hole peripheral region 75 by the wiper 51 passes through the second overlapping region 72, and therefore is less likely to enter the groove 68. This makes it possible to reduce staining of the print medium P and poor ink ejection caused by the ink in the groove 68.

[0077] <Variation 5> In the head 20 according to the fifth modification, the outer periphery 62 of the water-repellent film 60 has a shape similar to the edge of the nozzle hole 22 in the above-described embodiment and modifications 1 to 4.

[0078] 3 to 8A, the edge of the nozzle hole 22 is circular. In contrast, the outer peripheral edge 62 of the water-repellent film 60 surrounding the periphery of this nozzle hole 22 is circular, with a diameter larger than the diameter of the nozzle hole 22, and is disposed so as to share a center with the nozzle hole 22. Therefore, the dimension between the edge of the nozzle hole 22 and the outer peripheral edge 62 of the water-repellent film 60 in the circumferential direction is constant.

[0079] 9, the edge of the nozzle hole 22 is rectangular. In contrast, the outer peripheral edge 62 of the water-repellent film 60 that surrounds the periphery of this nozzle hole 22 is rectangular and its size is larger than the size of the nozzle hole 22. The dimensions of the edge of the nozzle hole 22 and the outer peripheral edge 62 of the water-repellent film 60 in the front-rear and left-right directions are equal to each other.

[0080] In this way, the outer peripheral edge 62 of the water-repellent film 60 has a shape similar to the edge of the nozzle hole 22. As a result, the water-repellent film 60 uniformly covers the periphery of the nozzle hole 22, and the wiper 51 can remove ink on the water-repellent film 60 around the nozzle hole 22, reducing ink ejection defects.

[0081] <Variation 6> 10, in the head 20 according to the sixth modification, the water-repellent film 60 has a dimension L in the row direction in which the nozzles 21 are lined up that is longer than a dimension M in the direction perpendicular to the row direction. Note that, hereinafter, the row direction may be referred to as the front-to-rear direction, and the direction perpendicular to the row direction may be referred to as the left-to-right direction.

[0082] Specifically, the multiple nozzles 21 are arranged at intervals in the front-rear direction to form a nozzle row 29. The nozzle holes 22 of the nozzles 21 are provided at the centers of the outer periphery 62 of the water-repellent film 60 in both the front-rear direction and the left-right direction. The water-repellent film 60 has an elliptical or oval shape, and its dimension M in the left-right direction is smaller than its dimension L in the front-rear direction. The inner periphery 61 of the water-repellent film 60 is arranged so as to overlap the edge of the nozzle holes 22 in the up-down direction.

[0083] Therefore, in the front-to-rear direction, the dimension L1 between the front end of the inner peripheral edge 61 and the front end of the outer peripheral edge 62 is equal to the dimension L1 between the rear end of the inner peripheral edge 61 and the rear end of the outer peripheral edge 62. In addition, in the left-to-right direction, the dimension M1 between the left end of the inner peripheral edge 61 and the left end of the outer peripheral edge 62 and the dimension M1 between the right end of the inner peripheral edge 61 and the right end of the outer peripheral edge 62 are equal to each other.

[0084] Because the dimension M1 of this water-repellent film 60 in the left-right direction is smaller than the dimension L1 in the front-to-rear direction, the mechanical strength of the water-repellent film 60 is lower in the left-to-right direction than in the front-to-rear direction. As a result, even if stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 caused by ink, the water-repellent film 60 on the left and right sides of the inner circumferential edge 61 is more likely to be damaged by this swelling than the water-repellent film 60 in front and behind the inner circumferential edge 61. Due to this damage to the water-repellent film 60, the stress on the water-repellent film 60 caused by the swelling of the nozzle plate 24 is alleviated, and damage to the water-repellent film 60 can be reduced.

[0085] Furthermore, damage to the water-repellent film 60 on the left or right side of the inner circumferential edge 61 may cause the ink ejection direction from the nozzle holes 22 to deviate left or right from the desired direction. This deviation in the ink ejection direction coincides with the direction in which the head 20, in which the nozzle holes 22 are provided, moves by the carriage 41. Therefore, by adjusting the timing of ink ejection from the nozzle holes 22 of the head 20 that moves left or right, it is possible to reduce the deviation in the ink ejection direction caused by damage to the water-repellent film 60. Therefore, it is possible to continue printing while reducing the deviation in the ink ejection direction, without replacing the head 20, etc.

[0086] <Variation 7> In the head 20 according to variant example 7, in variant example 6, as shown in the example of Figure 11, in a direction perpendicular to the column direction, the dimension of the water-repellent film 60 between one end of the outer peripheral edge 62 and one end of the inner peripheral edge 61 is longer than the dimension of the water-repellent film 60 between the other end of the outer peripheral edge 62 and the other end of the inner peripheral edge 61.

[0087] Specifically, the nozzle hole 22 is provided at the center of the outer peripheral edge 62 of the water-repellent film 60 in the front-to-rear direction. Because the edge of this nozzle hole 22 and the inner peripheral edge 61 overlap each other, the dimension L1 between the front end of the inner peripheral edge 61 and the front end of the outer peripheral edge 62 and the dimension L1 between the rear end of the inner peripheral edge 61 and the rear end of the outer peripheral edge 62 are equal to each other in the front-to-rear direction. In contrast, the nozzle hole 22 is provided to one side of the center of the outer peripheral edge 62 of the water-repellent film 60 in the left-to-right direction, that is, to the left in the example of FIG. 11 . Therefore, the dimension M2 between the left end of the inner peripheral edge 61 and the left end of the outer peripheral edge 62 in the left-to-right direction is smaller than the dimension M3 between the right end of the inner peripheral edge 61 and the right end of the outer peripheral edge 62.

[0088] In this way, the dimension M2 of the water-repellent film 60 to the left of the inner circumferential edge 61 is smaller than the dimensions of other portions, such as the dimension L1 in front of the inner circumferential edge 61, the dimension L1 behind the inner circumferential edge 61, and the dimension M3 to the right. Therefore, the mechanical strength of the water-repellent film 60 is lower to the left of the inner circumferential edge 61 than in other portions. As a result, even if stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 by ink, the water-repellent film 60 to the left of the inner circumferential edge 61 is more likely to be damaged by this swelling. This damage to the water-repellent film 60 relieves the stress on the water-repellent film 60 caused by the swelling of the nozzle plate 24, and damage to the water-repellent film 60 can be reduced.

[0089] Furthermore, in each of the multiple water-repellent films 60 surrounding the inner periphery 61 in the nozzle row 29, the portion to the left of the inner periphery 61 is more susceptible to damage than other portions. In this way, the same portion (for example, the portion to the left of the inner periphery 61) of each of the multiple water-repellent films 60 is damaged, and the direction of damage from the inner periphery 61 can be aligned for the multiple water-repellent films 60 in the nozzle row 29. Therefore, even if damage to the water-repellent film 60 causes the ink ejection direction from the nozzle holes 22 to deviate from the desired direction, it is easy to reduce the deviation in the ejection direction by adjusting the timing of ink ejection from the nozzle holes 22 of the head 20 that moves left and right.

[0090] <Variation 8> In the head 20 according to Modification 8, in the above-described embodiment and Modifications 1 to 7, the multiple water-repellent films 60 are arranged at intervals from each other in the row direction in which the multiple nozzles 21 are arranged, as shown in the examples of Figures 10 to 12. Note that the multiple water-repellent films 60 in Figures 4 to 9 may also be arranged at intervals from each other in the row direction, similar to the water-repellent films 60 in Figures 10 to 12.

[0091] Specifically, a plurality of nozzle holes 22 are arranged in the front-rear direction on the ejection surface 24a, and a water-repellent film 60 is provided around each nozzle hole 22. Two water-repellent films 60 arranged consecutively in the front-rear direction are not connected to each other, but are spaced apart. This allows, for example, even if stress is generated in the water-repellent films 60 due to swelling of the nozzle plate 24 caused by ink, the water-repellent films 60 deform and move independently of each other due to this swelling. Therefore, the stress on the water-repellent film 60 caused by swelling of the nozzle plate 24 is reduced compared to when multiple water-repellent films 60 are connected, thereby reducing damage to the water-repellent film 60.

[0092] <Variation 9> In the head 20 according to the ninth modification, as shown in the examples of FIGS. 12 and 13 in the above-described embodiment and modifications 2 to 8, the plurality of nozzles 21 includes a plurality of first nozzles 21a and a plurality of second nozzles 21b. The plurality of first nozzles 21a form a first nozzle row 29a extending along a row direction perpendicular to the direction of relative movement of the wiper 51 with respect to the ejection surface 24a. The plurality of second nozzles 21b form a second nozzle row 29b extending along the row direction. The first nozzles 21a and the second nozzles 21b are arranged alternately in the row direction. The water-repellent film 60 includes a first water-repellent film 60a surrounding the periphery of the first nozzle 21a and a second water-repellent film 60b surrounding the periphery of the second nozzle 21b. The first water-repellent film 60a has a first notch 69, and the second water-repellent film 60b has a second notch 70. When viewed along the relative movement direction of the wiper 51 with respect to the ejection surface 24a, the first notch 69 is not provided within a third overlapping region 73 that overlaps with the nozzle hole 22 of the second nozzle 21b but is provided outside the third overlapping region 73, the first water-repellent film 60a is provided within the third overlapping region 73, the second notch 70 is not provided within a fourth overlapping region 74 that overlaps with the nozzle hole 22 of the first nozzle 21a but is provided outside the fourth overlapping region 74, and the second water-repellent film 60b is provided within the fourth overlapping region 74.

[0093] Specifically, the first nozzles 21a and the second nozzles 21b are nozzles 21 that communicate with the same tank 12 (FIG. 1) and eject the same type of ink. The first nozzles 21a are arranged in a row at intervals in the front-rear direction to form a first nozzle row 29a. The second nozzles 21b are arranged in a row at intervals in the front-rear direction to form a second nozzle row 29b. The first nozzle row 29a and the second nozzle row 29b are aligned in the left-right direction.

[0094] Furthermore, when viewed in the left-right direction, the first nozzles 21a and the second nozzles 21b are arranged alternately so that the first nozzles 21a and the second nozzles 21b are lined up alternately in the front-to-back direction. In other words, when an imaginary line is extended in the left-right direction from the first nozzle 21a, the imaginary line extended in the left-right direction from the first nozzle 21a does not overlap with any of the second nozzles 21b belonging to the second nozzle row 29b at its intersection with the second nozzle row 29b. Furthermore, when an imaginary line is extended in the left-right direction from the second nozzle 21b, the imaginary line extended in the left-to-right direction from the second nozzle 21b does not overlap with any of the first nozzles 21a belonging to the first nozzle row 29a at its intersection with the first nozzle row 29a.

[0095] 12, the first nozzle 21a provided between two second nozzles 21b in the front-to-rear direction is closer to the front second nozzle 21b than the rear second nozzle 21b of the two second nozzles 21b. Therefore, in the front-to-rear direction, the dimension N1 between the first nozzle 21a and the front second nozzle 21b is smaller than the dimension N2 between the first nozzle 21a and the rear second nozzle 21b.

[0096] The third overlapping region 73 is a region that overlaps with the second nozzle hole 22b, which is the nozzle hole 22 of the second nozzle 21b, when viewed along the left-right direction, for example, and is a region between a straight line 73a that passes through the front end of the second nozzle hole 22b and extends in the left-right direction, and a straight line 73b that passes through the rear end of the second nozzle hole 22b and extends in the left-right direction.Furthermore, the fourth overlapping region 74 is a region that overlaps with the first nozzle hole 22a, which is the nozzle hole 22 of the first nozzle 21a, when viewed along the left-right direction, for example, and is a region between a straight line 74a that passes through the front end of the first nozzle hole 22a and extends in the left-right direction, and a straight line 74b that passes through the rear end of the first nozzle hole 22a and extends in the left-right direction.

[0097] The first water-repellent film 60a surrounds the periphery of the first nozzle hole 22a and has, inside its outer circumferential edge 62, a first notch 69 where no film is formed, and a fifth film-forming region where a film is formed, which is a region other than the first notch 69. The first water-repellent film 60a also has a fourth overlapping region 74 of the first nozzle hole 22a and a third overlapping region 73 of the second nozzle hole 22b arranged forward of the first nozzle hole 22a in the front-to-rear direction.

[0098] The first notch 69 is, for example, linear and extends radially, for example, in a direction inclined relative to the front-rear and left-right directions. The dimension between the inner peripheral edge 61 and the end of the first notch 69 closest to the inner peripheral edge 61 in the radial direction is greater than a predetermined dimension H. Therefore, the first notch 69 is provided outside the inner film region 63, which is the predetermined dimension H or less from the inner peripheral edge 61 along the radial direction. As a result, the first notch 69 is not provided in the inner film region 63, and the inner film region 63 is a fifth film formation region that covers the periphery of the nozzle hole 22.

[0099] The four first notches 69 are provided rearward of the third overlapping region 73 in the front-to-rear direction. Therefore, the first notches 69 are not provided in the third overlapping region 73 in the first water-repellent film 60a, but are provided outside the third overlapping region 73. Furthermore, of the four first notches 69, the front two first notches 69 are provided forward of the fourth overlapping region 74, and the rear two first notches 69 are provided rearward of the fourth overlapping region 74. Therefore, the first notches 69 are not provided in the fourth overlapping region 74 in the first water-repellent film 60a, but are provided outside the fourth overlapping region 74. As a result, the third overlapping region 73 and the fourth overlapping region 74 in the first water-repellent film 60a are a fifth film-forming region.

[0100] The second water-repellent film 60b surrounds the periphery of the second nozzle hole 22b and has, inside its outer circumferential edge 62, a second notch 70 where no film is formed, and a sixth film-forming region where a film is formed, which is a region other than the second notch 70. The second water-repellent film 60b also has a third overlapping region 73 of the second nozzle hole 22b and a fourth overlapping region 74 of the first nozzle hole 22a arranged rearward of the second nozzle hole 22b in the front-rear direction.

[0101] The second notch 70 is linear and extends radially, for example, in a direction inclined relative to the front-rear and left-right directions. The dimension between the inner peripheral edge 61 and the end of the second notch 70 closest to the inner peripheral edge 61 in the radial direction is greater than a predetermined dimension H. Therefore, the second notch 70 is provided radially outside the inner film region 63, which is less than the predetermined dimension H from the inner peripheral edge 61. As a result, the second notch 70 is not provided in the inner film region 63, and the inner film region 63 is a sixth film formation region that covers the periphery of the nozzle hole 22.

[0102] The four second notches 70 are provided forward of the fourth overlapping region 74 in the front-to-rear direction. Therefore, the second notches 70 are not provided in the fourth overlapping region 74 in the second water-repellent film 60b, but are provided outside the fourth overlapping region 74. Furthermore, of the four second notches 70, the front two second notches 70 are provided forward of the third overlapping region 73, and the rear two second notches 70 are provided rearward of the third overlapping region 73. Therefore, the second notches 70 are not provided in the third overlapping region 73 in the second water-repellent film 60b, but are provided outside the third overlapping region 73. As a result, the third overlapping region 73 and the fourth overlapping region 74 in the second water-repellent film 60b are a sixth film-forming region.

[0103] 13, the first nozzle 21a provided between two second nozzles 21b is provided at equal intervals from both of the two second nozzles 21b in the front-rear direction. Therefore, in the front-rear direction, the dimension N3 between the first nozzle 21a and the second nozzle 21b in front of it and the dimension N4 between the first nozzle 21a and the second nozzle 21b behind it are equal to each other. Furthermore, in the front-rear direction, the second nozzle 21b provided between the two first nozzles 21a is provided at equal intervals from both of the two first nozzles 21a. Therefore, in the front-rear direction, the dimension N5 between the second nozzle 21b and the first nozzle 21a in front of it and the dimension N6 between the second nozzle 21b and the first nozzle 21a behind it are equal to each other.

[0104] The first water-repellent film 60a is provided with a fourth overlapping region 74 of the first nozzle hole 22a, a third overlapping region 73 of the second nozzle hole 22b in front of the fourth overlapping region 74, a third overlapping region 73 of the second nozzle hole 22b behind the fourth overlapping region 74, and two first notches 69. The first notches 69 are linear and extend radially, for example, along the front-to-rear direction. The distance between the inner peripheral edge 61 and the end of the first notch 69 closest to the inner peripheral edge 61 in the radial direction is greater than a predetermined dimension H. Therefore, the first notches 69 are provided radially outward from the inner film region 63, which is less than the predetermined dimension H from the inner peripheral edge 61. As a result, the first notches 69 are not provided in the inner film region 63, and the inner film region 63 is a fifth film formation region that covers the periphery of the nozzle hole 22.

[0105] The two first notches 69 are provided between the front third overlapping region 73 and the rear third overlapping region 73 in the front-rear direction. Therefore, the first notches 69 are not provided in the third overlapping region 73 but are provided outside the third overlapping region 73. Furthermore, of the two first notches 69, one first notch 69 is provided in front of the fourth overlapping region 74 in the front-rear direction, and the other first notch 69 is provided behind the fourth overlapping region 74 in the front-rear direction. Therefore, the first notch 69 is not provided in the fourth overlapping region 74 but is provided outside the fourth overlapping region 74. As a result, the third overlapping region 73 and the fourth overlapping region 74 of the first water-repellent film 60a are fifth film formation regions.

[0106] The second water-repellent film 60b is provided with a third overlapping region 73 of the second nozzle hole 22b, a fourth overlapping region 74 of the first nozzle hole 22a in front of the third overlapping region 73, a fourth overlapping region 74 of the first nozzle hole 22a behind the third overlapping region 73, and two second notches 70. The second notches 70 are linear and extend radially, for example, along the front-to-rear direction. The distance between the inner peripheral edge 61 and the end of the second notch 70 closest to the inner peripheral edge 61 in the radial direction is greater than a predetermined dimension H. Therefore, the second notch 70 is provided radially outward from the inner film region 63, which is less than the predetermined dimension H from the inner peripheral edge 61. As a result, the second notch 70 is not provided in the inner film region 63, and the inner film region 63 is a sixth film formation region that covers the periphery of the nozzle hole 22.

[0107] The two second notches 70 are provided between the front fourth overlapping region 74 and the rear fourth overlapping region 74 in the front-to-rear direction. Therefore, the second notches 70 are not provided in the fourth overlapping region 74 but are provided outside the fourth overlapping region 74. Furthermore, of the two second notches 70, one second notch 70 is provided in front of the third overlapping region 73 in the front-to-rear direction, and the other second notch 70 is provided behind the third overlapping region 73 in the front-to-rear direction. Therefore, the second notch 70 is not provided in the third overlapping region 73 but is provided outside the third overlapping region 73. As a result, the third overlapping region 73 and the fourth overlapping region 74 of the second water-repellent film 60b are a sixth film formation region.

[0108] In this way, the first notch 69 and the second notch 70 are provided outside the third overlapping region 73, and the third overlapping region 73 is the fifth film-forming region or the sixth film-forming region. This reduces the amount of ink removed from the second nozzle hole 22b by the wiper 51 passing through the third overlapping region 73 and entering the first notch 69 and the second notch 70, even when the wiper 51 moves relatively left and right with respect to the ejection surface 24a while contacting the ejection surface 24a or the water-repellent film 60. This reduces staining of the print medium P and ink ejection failure caused by the ink in the second nozzle hole 22b at the first notch 69 and the second notch 70.

[0109] Furthermore, the first notch 69 and the second notch 70 are provided outside the fourth overlapping region 74, which is the fifth film-forming region or the sixth film-forming region. This reduces the amount of ink removed from the first nozzle hole 22a by the wiper 51 passing through the fourth overlapping region 74 and entering the first notch 69 and the second notch 70, even when the wiper 51 moves relatively left and right with respect to the ejection surface 24a while contacting the ejection surface 24a or the water-repellent film 60. This reduces staining of the print medium P and ink ejection failure caused by the ink in the first nozzle hole 22a at the first notch 69 and the second notch 70.

[0110] <Modification 10> The head 20 of variant 10, in the above-mentioned embodiment and variants 1 to 9, has an outer water-repellent film 60e that is provided radially of the nozzle hole 22 and outside the edge of the second end 27c2, as shown in Figures 14A and 14B.

[0111] Specifically, in addition to the inner water-repellent film 60 provided in an inner film region J that is more inward than the edge of the second end 27c2, the ejection surface 24a is provided with an outer water-repellent film 60e in an outer region I that is more outward than the edge of the second end 27c2. The inner water-repellent film 60 is not provided in the outer region I of the ejection surface 24a, and the outer water-repellent film 60e is not provided in the inner film region J of the ejection surface 24a, so that the inner water-repellent film 60 and the outer water-repellent film 60e are separated. The outer water-repellent film 60e has a circular inner edge that surrounds the periphery of the outer peripheral edge 62 of the inner water-repellent film 60. A gap 76 of a constant dimension is provided in the radial direction between the outer peripheral edge 62 of the inner water-repellent film 60 and the inner edge of the outer water-repellent film 60e.

[0112] In this way, a wide area of ​​the ejection surface 24a is covered by the outer water-repellent film 60e in addition to the inner water-repellent film 60, so that a large amount of ink on the water-repellent film 60 can be easily removed by the wiper 51. Furthermore, the inner water-repellent film 60 and the outer water-repellent film 60e are not connected to each other. As a result, even if stress is generated in the water-repellent film 60 due to swelling of the nozzle plate 24 caused by ink, the inner water-repellent film 60 and the outer water-repellent film 60e deform or move independently of each other due to this swelling. Therefore, the stress on the water-repellent film 60 due to swelling of the nozzle plate 24 is reduced compared to when multiple water-repellent films 60 are connected, and damage to the water-repellent film 60 can be reduced.

[0113] <Variation 11> The head 20 of variant 11, in the above-mentioned embodiment and variants 1 to 10, is provided with an elastic film 77 laminated between the ejection surface 24a and the water-repellent film 60 and having an elastic modulus smaller than that of the water-repellent film 60, as shown in the example of Figure 15.

[0114] Specifically, the elastic film 77 is made of an elastic material such as rubber or elastomer. The elastic modulus of the elastic film 77 is smaller than that of the water-repellent film 60, and the elastic film 77 is more easily deformed than the water-repellent film 60. The elastic film 77 is interposed between the ejection surface 24a of the nozzle plate 24 and the water-repellent film 60. Therefore, when the nozzle plate 24 swells due to ink, the elastic film 77 deforms in response to the swelling. This reduces the stress on the water-repellent film 60 caused by the swelling of the nozzle plate 24, thereby reducing damage to the water-repellent film 60.

[0115] <Other variations> 2, the descender plate is formed of a plurality of flow path plates 25, for example, the first flow path plate 25a to the fourth flow path plate 25d, but the descender plate may be formed of a single flow path plate 25. In addition, the pressure chamber plate is formed of a single fifth flow path plate 25e, but the pressure chamber plate may be formed of a plurality of flow path plates 25.

[0116] In the above-described embodiment and all modified examples, the head 20 separately includes a descender plate in which the descender 27c is formed, and a pressure chamber plate in which the pressure chamber 27b is formed, as shown in the example of FIG. 2. However, the configuration of the head 20 is not limited to this. For example, as shown in the example of FIG. 16, the head 20 may include a flow path plate 25 in which the descender 27c and the pressure chamber 27b are formed. In this case, the descender 27c and the pressure chamber 27b are formed in the same single flow path plate 25. This flow path plate 25 is stacked on the nozzle plate 24.

[0117] In the above embodiment and all modified examples, the head 20 is moved relative to the fixed wiper 51, thereby moving the wiper 51 relative to the ejection surface 24a of the head 20. However, the movement of the wiper 51 is not limited to this, as long as the wiper 51 moves relative to the ejection surface 24a of the head 20. In other words, both the wiper 51 and the head 20 may be moved, or the wiper 51 may be moved relative to a stationary head 20.

[0118] It should be noted that many modifications and other embodiments of the present disclosure will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present disclosure. [Explanation of symbols]

[0119] 10: Printer 20: Head 21: Nozzle 21a: First nozzle 21b: Second nozzle 22: Nozzle hole 24: Nozzle plate 24a:Discharge surface 25: Flow channel plate 27b: Pressure chamber 27c : Descendant 27c1 :1st end 27c2: 2nd end 29: Nozzle row 29a: First nozzle row 29b: Second nozzle row 51: Wiper 60: Water-repellent film 60a: First water-repellent film 60b: Second water-repellent film 60e: Water-repellent film 61: Inner edge 62: Outer edge 65: Notch 66: Notch 67: Notch 68: Groove 69: First notch 70: Second notch 71 :Area 72 :Area 73 :Area 74 :Area 75: Area around the nozzle hole 77: Elastic membrane

Claims

1. a nozzle plate in which a plurality of nozzles having nozzle holes for ejecting ink are formed; a pressure chamber plate in which a pressure chamber is formed to which pressure is applied for ejecting ink from the nozzle hole; a descender plate having a first end connected to the pressure chamber and a second end connected to the nozzle and having a diameter larger than a diameter of the nozzle, the descender plate being laminated between the nozzle plate and the pressure chamber plate; a water-repellent film provided on the ejection surface of the nozzle plate on which the nozzle holes are formed, When viewed along a stacking direction in which the descender plate is stacked on the nozzle plate, the water-repellent film has an inner peripheral edge that overlaps an edge of the nozzle hole, and an outer peripheral edge that is provided between the inner peripheral edge and an edge of the second end. Inkjet head.

2. the water-repellent film is provided with a stress relaxation portion at a position greater than a predetermined distance from the inner circumferential edge along a radial direction of the nozzle hole, the stress relaxation portion having a mechanical strength lower than that of a portion at or less than the predetermined distance from the inner circumferential edge.

2. The ink-jet head according to claim 1.

3. the stress relaxation portion is an annular notch surrounding the nozzle hole at a position greater than the predetermined dimension from the inner circumferential edge along a radial direction of the nozzle hole, 3. The ink-jet head according to claim 2.

4. the stress relaxation portion is a linear notch extending from a position that is greater than the predetermined dimension from the inner peripheral edge along the radial direction of the nozzle hole toward the outer peripheral edge along the radial direction of the nozzle hole, 3. The ink-jet head according to claim 2.

5. the stress relaxation portions are dashed-line shaped notches provided at positions greater than the predetermined dimension from the inner peripheral edge along the radial direction of the nozzle hole, with the nozzle hole interposed therebetween; 3. The ink-jet head according to claim 2.

6. the stress relaxation portion has grooves provided at a position greater than the predetermined dimension from the inner peripheral edge along a radial direction of the nozzle hole, the grooves sandwiching the nozzle hole therebetween; 3. The ink-jet head according to claim 2.

7. a wiper that moves relative to the ejection surface; the stress relaxation portion extends along a relative movement direction of the wiper with respect to the ejection surface; 7. The ink-jet head according to claim 5 or 6.

8. a wiper that moves relative to the ejection surface; the stress relaxation portion is provided outside a first overlapping region that overlaps with the nozzle hole when viewed along a relative movement direction of the wiper with respect to the ejection surface. The ink-jet head according to any one of claims 4 to 6.

9. a wiper that moves relative to the ejection surface; the stress relaxation portion is provided outside a second overlapping region that overlaps a nozzle hole peripheral region that is a predetermined dimension or less from an edge of the nozzle hole along a radial direction of the nozzle hole and a second overlapping region that overlaps with the nozzle hole peripheral region when viewed along a relative movement direction of the wiper with respect to the ejection surface. The ink-jet head according to any one of claims 4 to 6.

10. The predetermined dimension is equal to or greater than the diameter of the nozzle hole. The ink-jet head according to any one of claims 2 to 6.

11. the outer circumferential edge of the water-repellent film has a shape similar to that of the edge of the nozzle hole; 2. The ink-jet head according to claim 1.

12. a dimension of the water-repellent film in a row direction in which the nozzles are arranged is longer than a dimension of the water-repellent film in a direction perpendicular to the row direction; 2. The ink-jet head according to claim 1.

13. a dimension of the water-repellent film between one end of the outer circumferential edge and one end of the inner circumferential edge in a direction perpendicular to the row direction is longer than a dimension of the water-repellent film between the other end of the outer circumferential edge and the other end of the inner circumferential edge; 13. The ink-jet head according to claim 12.

14. In a column direction in which the nozzles are arranged, the water-repellent films are arranged at intervals from each other.

2. The ink-jet head according to claim 1.

15. a wiper that moves relative to the ejection surface; The plurality of nozzles includes a plurality of first nozzles and a plurality of second nozzles, the first nozzles form a first nozzle row extending along a row direction perpendicular to a relative movement direction of the wiper with respect to the ejection surface, the plurality of second nozzles form a second nozzle row extending along the row direction, the first nozzles and the second nozzles are arranged so as to be alternated in the column direction, the water-repellent film includes a first water-repellent film surrounding the first nozzle and a second water-repellent film surrounding the second nozzle, the first water-repellent film has a first notch; the second water-repellent film has a second notch; when viewed along a relative movement direction of the wiper with respect to the ejection surface, the first notch is not provided within a third overlapping region overlapping with the nozzle hole of the second nozzle but is provided outside the third overlapping region, the first water-repellent film is provided within the third overlapping region, the second notch is not provided within a fourth overlapping region overlapping with the nozzle hole of the first nozzle but is provided outside the fourth overlapping region, and the second water-repellent film is provided within the fourth overlapping region.

2. The ink-jet head according to claim 1.

16. an outer water-repellent film provided along a radial direction of the nozzle hole and outside an edge of the second end; 2. The ink-jet head according to claim 1.

17. an elastic film laminated between the ejection surface and the water-repellent film and having an elastic modulus smaller than that of the water-repellent film; 2. The ink-jet head according to claim 1.

18. a nozzle plate in which a plurality of nozzles having nozzle holes for ejecting ink are formed; a flow path plate formed with a pressure chamber to which pressure for ejecting ink from the nozzle hole is applied, a descender having a first end connected to the pressure chamber and a second end connected to the nozzle and having a diameter larger than a diameter of the nozzle, and the descender is laminated on the nozzle plate; a water-repellent film provided on the ejection surface of the nozzle plate on which the nozzle holes are formed, the water-repellent film has an inner peripheral edge that overlaps an edge of the nozzle hole, and an outer peripheral edge that is provided between the inner peripheral edge and an edge of the second end, when viewed along a stacking direction in which the flow path plate is stacked on the nozzle plate. Inkjet head.

19. The inkjet head according to claim 1 or 18 is provided. Printer.

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