Liquid ejection head and method for manufacturing the same

Abstract

To provide a liquid ejection head that can be improved in electric reliability.SOLUTION: A liquid ejection head 1 comprises: a recording element substrate 2 having an ejection port 2a for ejecting liquid; and an electric wiring board 3 which comprises a wiring portion 6 and in which one end of the wiring portion 6 is electrically connected to the recording element substrate 2 through an electric connection portion 70. The electric wiring board 3 has: a first film 21; a second film 20 which opposes to the wiring portion 6, a width of at least a part of which is narrower than a width of the first film 21; and an adhesion layer 30 which adheres the first film 21 to the second film 20. The first film 21 has a first area 21a coming in contact with the adhesive layer 30 and a second area 21b positioned closer to outside than the first area 21a, in a width direction. A side surface 30a at the second area 21b side, of the adhesion layer 30 is covered with first sealing material 9.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid ejection head that ejects liquid and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 describes a liquid ejection head having a liquid ejection substrate that ejects liquid and an electric wiring substrate including wiring, in which the pads of the liquid ejection substrate and the wiring of the electric wiring substrate are electrically connected by wire bonding. In this liquid ejection head, the wire bonding portion (electrical connection portion) is covered with a sealant. This makes it possible to prevent mist, which is a minute droplet generated during a recording operation in which liquid is ejected, from adhering to the electrical connection portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-205903 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the liquid ejection head described in Patent Document 1, the electric wiring board has a structure in which wiring is sandwiched between two films and fixed with an adhesive, and the side surface of the adhesive layer is exposed at the end surface of the end in the width direction of the electric wiring board. Therefore, when mist adheres to the end surface of the electric wiring board, the components of the mist permeate into the adhesive layer and reach the wiring, which may result in electrical malfunction.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a liquid ejection head capable of improving electrical reliability. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, according to one aspect of the present invention, there is provided a liquid ejection head having a recording element substrate having an ejection port for ejecting liquid, and an electrical wiring substrate having a wiring portion, one end of which is electrically connected to the recording element substrate via an electrical connection portion, wherein the electrical wiring substrate has a first film, a second film which faces the wiring portion and has at least a portion of a width narrower than the width of the first film, and an adhesive layer which adheres the first film and the second film, wherein the first film has a first region which contacts the adhesive layer and a second region which is positioned outside the first region in the width direction, and a side of the adhesive layer facing the second region is covered with a sealant.

[0007] According to another aspect of the present invention, there is provided a liquid ejection head having a recording element substrate having an ejection port for ejecting liquid, and an electrical wiring substrate having a wiring portion, one end of which is electrically connected to the recording element substrate via an electrical connection portion, wherein the electrical wiring substrate has a first film, a second film which faces the wiring portion and has at least a portion of a width narrower than the width of the first film, and an adhesive layer which adheres the first film to the second film, wherein in the width direction, an end of the first film is positioned outside the end of the narrowed portion of the second film, and at the outer end, a side of the adhesive layer is covered with a sealant. Effect of the Invention

[0008] According to the present invention, it is possible to suppress the penetration of mist components from the end faces of the electrical wiring board in the liquid ejection head into the inside, thereby improving electrical reliability. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a configuration of a liquid ejection head according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a schematic diagram showing a state in which a recording element substrate and an electric wiring substrate are fixed to a supporting member. [Diagram 3] 4 is a schematic diagram showing a state in which a recording element substrate and an electric wiring substrate are electrically connected by wire bonding. FIG. [Figure 4] FIG. 2 is a schematic diagram showing a state in which a first sealing material is applied to an electric wiring board and an electric connection portion. [Diagram 5] 1A to 1C are process diagrams illustrating a procedure for producing an electric wiring board. [Figure 6] FIG. 4 is a schematic diagram illustrating a configuration of a liquid ejection head of a comparative example. [Figure 7] FIG. 1 is a diagram showing the configuration of an electric wiring board having a wiring portion with a two-layer structure. [Figure 8] 13A and 13B are schematic diagrams showing modified examples of the second film of the electric wiring board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the embodiment is merely an example, and the scope of the present invention is not limited to the embodiment.

[0011] Fig. 1 is a schematic diagram showing the configuration of a liquid ejection head according to one embodiment of the present invention. Fig. 1(a) is a perspective view, Fig. 1(b) is a top view, and Fig. 1(c) is a cross-sectional view showing a cross section of the electric wiring board shown in Fig. 1(b) along line AA. In Fig. 1(a), Fig. 1(b), and Fig. 1(c), the X direction, the Y direction, and the Z direction correspond to the width direction, the length direction, and the thickness direction of the electric wiring board, respectively.

[0012] As shown in FIG. 1(a) and FIG. 1(b), the liquid ejection head 1 has a recording element substrate 2, an electric wiring substrate 3, and a support member 4. The recording element substrate 2 has a first surface 2b provided with a plurality of ejection ports 2a for ejecting liquid such as ink. Although not shown, the recording element substrate 2 has a plurality of pressure chambers each communicating with the plurality of ejection ports 2a, and a plurality of flow paths each communicating with these pressure chambers. A recording element, which is an energy generating element that generates energy for ejecting liquid, is provided adjacent to each pressure chamber. For example, a heating element (electrothermal conversion element) or a piezoelectric element can be used as the recording element.

[0013] The surface of the recording element substrate 2 opposite to the first surface 2b is adhered to a support member 4. Although not shown, the support member 4 has a communication port for supplying liquid to the recording element substrate 2, a common supply flow path, and a common recovery flow path. The liquid is supplied to the recording element substrate 2 from the common supply flow path via the communication port. Liquid not ejected from each ejection port 2a is recovered via the common recovery flow path.

[0014] The electric wiring board 3 has an elongated shape. One end of the electric wiring board 3 in the longitudinal direction (Y direction) is bonded to the support member 4. The electric wiring board 3 has a wiring section 6 including a plurality of wirings extending in the Y direction, a first film 21, and a second film 20 facing the wiring section 6. The width W2 of the second film 20 is narrower than the width W1 of the first film 21. In this embodiment, the width W2 of the second film 20 is narrower than the width W1 of the first film 21 over the entire area in the longitudinal direction (Y direction) of the electric wiring board 3, but is not limited thereto. At least a part of the width of the second film 20 may be narrower than the width of the first film 21.

[0015] The wiring section 6 is, for example, a printed wiring, more preferably a conductive copper foil printed wiring. The wiring section 6 is sandwiched between a first film 21 and a second film 20. Although described in detail below, one end of the wiring section 6 is electrically connected to a terminal of the recording element substrate 2 via an electrical connection section. The electrical connection section is covered with a first sealing material 9 and a second sealing material 10. The other end of the wiring section 6 is electrically connected to a control board (not shown) for driving the liquid ejection head 1. An electrical signal for ejecting liquid is supplied from the control board to the recording element substrate 2 via the wiring section 6.

[0016] The structure of the electric wiring board 3 will be described in detail with reference to Fig. 1(c). The wiring portion 6 is sandwiched between the first film 21 and the second film 20. The first film 21 and the second film 20 are made of, for example, an insulating polyimide film, and are thin and flexible. The thickness of the first film 21 is, for example, 0.05 mm to 0.2 mm. The thickness of the second film 20 is, for example, 0.01 mm to 0.1 mm.

[0017] The adhesive layer 30 is made of an adhesive 22 and is disposed between the first film 21 and the second film 20. The adhesive layer 30 bonds the first film 21 and the second film 20. The first film 21 has a first region 21a in contact with the adhesive layer 30 and a second region 21b located outside the first region 21a in the width direction (X direction). The second region 21b extends in the longitudinal direction (Y direction) and is covered with a first sealing material 9. The side surface 30a of the adhesive layer 30 on the side of the second region 21b is also covered with the first sealing material 9. As can be seen from FIG. 1(a) and FIG. 1(b), the first sealing material 9 is applied so as to continuously cover the outer edge portion including both ends in the width direction and one end in the longitudinal direction (end on the electrical connection side) of the electrical wiring board 3. 1(a) and 1(b), the vicinity of the electrical connection part at the outer edge is covered with the second sealing material 10, and therefore the part where the first sealing material 9 is applied is hidden by the part of the second sealing material 10. Also, in FIG. 1(c), for the sake of convenience, the boundary between the first region 21a and the second region 21b is shown by a dashed line, but this is merely for the purpose of deepening understanding and does not indicate a difference in material, etc. In the other drawings, the dashed line of the boundary is also drawn with a similar purpose.

[0018] Next, a method for manufacturing the liquid ejection head 1 of this embodiment will be described with reference to FIGS. First, the process of fixing the recording element substrate 2 and the electric wiring substrate 3 to the support member 4 will be described.

[0019] 2 is a schematic diagram showing a state in which the recording element substrate 2 and the electric wiring substrate 3 are fixed to a support member 4. A thermosetting adhesive is used to fix a second surface of the recording element substrate 2 opposite to the first surface 2b to the support member 4. A thermosetting adhesive is also used to fix one end of the electric wiring substrate 3 in the longitudinal direction to the support member 4. The surface of the electric wiring substrate 3 that is fixed to the support member 4 is the surface on the side of the first film 21 (the back surface of the electric wiring substrate 3).

[0020] Although not shown, the recording element substrate 2 has a silicon substrate with a thickness of about 0.6 mm to 1 mm and an ejection port forming member in which the ejection port 2a is formed. Electric wiring and recording elements are provided on one surface of the silicon substrate. The silicon substrate has a flow path structure for forming a pressure chamber and a flow path. By joining the silicon substrate and the ejection port forming member, a pressure chamber communicating with the ejection port 2a, a liquid flow path communicating with the pressure chamber, a liquid supply path for supplying liquid to the liquid flow path, and the like are formed. The pressure chamber, the liquid flow path, and the liquid supply path can be formed using a photolithography technique. The electrical wiring can be formed, for example, using a film formation technique. Here, an electrothermal converter is used as the recording element. The electrothermal converter converts the power supplied via the wiring into thermal energy. By applying this thermal energy to the liquid in the pressure chamber, the liquid can be ejected from the ejection port 2a.

[0021] 2, the first surface 2b of the recording element substrate 2 is provided with a plurality of terminals 5 electrically connected to each recording element via an electric wiring. These terminals 5 are arranged in a line along the X direction at an end of the first surface 2b of the recording element substrate 2 adjacent to the electric wiring substrate 3. From the viewpoints of planarity, resistance when transmitting an electric signal, etc., it is preferable that each terminal 5 is gold plated.

[0022] The electric wiring board 3 is a flexible board having a thickness of, for example, 0.1 mm to 0.3 mm. The length in the Y direction of the second film 20 is shorter than the length in the Y direction of the first film 21, and both ends of the wiring portion 6 are exposed at both ends of the first film 21. At both ends in the width direction (X direction) of the electric wiring board 3, the end face of the first film 21 is located outside the end face of the second film 20, and the second region 21b of the first film 21 is exposed. The electric wiring board 3 having such a structure can be manufactured using mechanical processing such as punching or chemical techniques such as etching. A specific method for manufacturing the electric wiring board 3 will be described later.

[0023] The support member 4 may have any shape or material as long as it is capable of supplying liquid to the recording element substrate 2 and is capable of adhering the recording element substrate 2 and the electric wiring substrate 3 to the supporting surface. A wide range of materials can be selected for the support member 4, including resin, ceramic, and metal. In this embodiment, since the recording element substrate 2 and the electric wiring substrate 3 are fixed to the support member 4 using a thermosetting adhesive, it is preferable to use an alumina plate having excellent heat resistance for the support member 4.

[0024] Next, the wire bonding process will be described. 3 is a schematic diagram showing a state in which the terminals 5 of the recording element substrate 2 and the wiring portion 6 of the electric wiring substrate 3 are electrically connected by wire bonding. In this wire bonding, each terminal 5 of the recording element substrate 2 and one end of each wire of the wiring portion 6 are electrically connected by a wire 7. The wire bonding portion consisting of the multiple wires 7 is the electrical connection portion 70.

[0025] In the example of FIG. 3, for convenience, six terminals 5 of the recording element substrate 2 and six wires of the wiring section 6 are connected by six wires each, but the number of terminals 5, the number of wires, and the number of wires 7 can be set appropriately. Although it depends on the size of the recording element substrate 2, for example, the number of wires 7 may be about 50 to 200, and the pitch of the wires 7 may be about 50 μm to 500 μm. The length of the wires 7 is about 0.5 mm to 5 mm. The material of the wires 7 is gold, silver, copper, aluminum, etc., but is not limited to these. From the viewpoint of corrosion resistance and resistance during electrical signal transmission, it is preferable to use gold as the wires 7. There is also no particular limit to the diameter of the wires 7. As the wires 7, a general bonding wire having a diameter of 20 μm to 35 μm can be used. The electrical connection portion 70 may be an electrical connection method other than wire bonding, such as inner lead bonding. As described later, the present invention can be suitably used in a liquid ejection head in which the electrical connection portion 70 is covered with a sealant.

[0026] Next, the sealing process will be described. FIG. 4 is a schematic diagram showing a state in which the first sealing material 9 is applied to the widthwise end of the electric wiring board 3 and the electrical connection portion 70. At both widthwise ends of the electric wiring board 3, the second region 21b of the first film 21 is exposed, and the first sealing material 9 is applied to the exposed second region 21b so as to cover the side surface 30a of the adhesive layer 30 (see FIG. 1(c)). Specifically, the first sealing material 9 is applied to the concave corner (corner) formed by the second region 21b and the side surface 30a of the adhesive layer 30 by utilizing the capillary phenomenon. In addition, the first sealing material 9 is filled in the space including below each wire 7 of the electrical connection portion 70, and the first sealing material 9 is applied to cover the connection portion (exposed portion) between each terminal 5 and each wiring of the wiring portion 6 and the wire 7.

[0027] A dispenser can be used to apply the first sealing material 9. For example, the first sealing material 9 is applied while moving a needle in the following order: one end in the width direction of the electric wiring board 3, the electrical connection portion 70, and the other end in the width direction of the electric wiring board 3. This allows the first sealing material 9 to be applied to both ends in the width direction of the electric wiring board 3 and the electrical connection portion 70 in a single process. Note that, at the electrical connection portion 70, a needle is placed above the wires 7, and the first sealing material 9 is applied so as to drip from the gaps between the adjacent wires 7.

[0028] It is preferable to use a curable liquid resin for the first sealant 9. Examples of the curable liquid resin include epoxy resin, acrylic resin, epoxy acrylate resin, imide resin, and amide resin. The resin can be cured by two-liquid mixing curing in which a curing agent is mixed, heat curing by heating, UV curing by ultraviolet irradiation, or the like. In this embodiment, the first sealant 9 is required to have a suitable fluidity in order to fill the complicated parts of the electrical connection part 70 and the spaces below each wire 7. However, if the fluidity of the first sealant 9 is increased, the first sealant 9 may wet and spread, resulting in the wire 7 being exposed more than necessary. In consideration of this point, it is preferable to use a liquid resin with a viscosity of 10 to 100 Pa·s as the first sealant 9.

[0029] After the first sealing material 9 is applied, the second sealing material 10 is applied on the portion where the first sealing material 9 is applied so as to cover the space including above each wire 7 of the electrical connection portion 70 (see FIG. 1(a)). The second sealing material 10 covers the upper part of the electrical connection portion 70 to insulate and protect it. As the second sealing material 10, a curable liquid epoxy resin (acrylic resin, epoxy acrylate resin, imide resin, amide resin, etc.) can be used, as with the first sealing material 9. However, since the second sealing material 10 needs to maintain a state in which it covers the upper part of the electrical connection portion 70, it is preferable that the viscosity of the second sealing material 10 is higher than that of the first sealing material 9. For example, it is preferable to use a liquid resin with a viscosity of 100 to 500 Pa·s as the second sealing material 10.

[0030] Next, a method for producing the electric wiring board 3 will be specifically described. FIG. 5 is a process diagram for explaining the procedure for producing the electric wiring board 3. As shown in FIG. First, as shown in Fig. 5(a), a film 40 that is the base of the first film 21 is prepared. Next, as shown in Fig. 5(b), a wiring layer 41 that is the base of the wiring section 6 is adhered onto the film 40. Next, as shown in Fig. 5(c), a resist film 42 is formed on the surface of the wiring layer 41. Next, as shown in Fig. 5(d), the resist film 42 is exposed and developed using a mask having a pattern for forming each wire of the wiring section 6 to form a resist pattern 42a.

[0031] Next, as shown in FIG. 5(e), the wiring layer 41 is etched using the resist pattern 42a as a mask. Next, as shown in FIG. 5(f), the resist pattern 42a is removed (resist stripping), and each wiring of the wiring section 6 is formed. Next, as shown in FIG. 5(g), the second film 20 is produced by punching or etching using a resist. Finally, as shown in FIG. 5(e), the second film 20 is bonded onto the film 40 so as to cover each wiring of the wiring section 6. After bonding, the second film 20 is punched (divided) along cutting lines 43 (dashed lines) surrounding the periphery thereof, and the electric wiring board 3 is obtained.

[0032] According to the above-mentioned manufacturing procedure, a structure in which second region 21b of first film 21 is exposed at both ends of electric wiring board 3 in the width direction can be realized.

[0033] According to the liquid ejection head 1 of the present embodiment described above, the side surfaces 30a (exposed surfaces) of the adhesive layer 30 are covered with the first sealant 9 at both widthwise ends of the electric wiring board 3. Therefore, even if mist generated during a recording operation in which liquid is ejected adheres to both widthwise ends of the electric wiring board 3, it is possible to prevent the components of the mist from penetrating into the adhesive layer 30.

[0034] The effect of suppressing the penetration of the mist components will be specifically described below. First, the configuration of a liquid ejection head as a comparative example and the problem with the penetration of mist components will be described. Fig. 6 is a schematic diagram showing the configuration of a liquid ejection head of a comparative example, Fig. 6(a) is a top view, and Fig. 6(b) is a cross-sectional view showing the cross section of the electric wiring board shown in Fig. 6(a) taken along line AA.

[0035] The liquid ejection head 100 of the comparative example has the same configuration as the liquid ejection head 1 shown in Fig. 1, except that the configuration of the electric wiring board 3A is different from that of the electric wiring board 3. The same components as those in the liquid ejection head 1 are given the same reference numerals. Here, in order to avoid duplication of explanation, detailed explanations of the components that are the same as those in the liquid ejection head 1 will be omitted.

[0036] As shown in Figures 6(a) and 6(b), the electric wiring board 3A has a wiring portion 6, a first film 21, and a second film 20A. The width of the second film 20A is the same as the width of the first film 21. The wiring portion 6 is sandwiched between the first film 21 and the second film 20A, and the opposing surfaces of the first film 21 and the second film 20A are fixed with an adhesive 22. At both ends in the width direction (X direction) of the electric wiring board 3A, side surfaces 30a of the adhesive layer 30 are exposed.

[0037] In the liquid ejection head 100 of the comparative example, mist generated during a recording operation to eject liquid may adhere to the side surface 30a of the adhesive layer 30 at both ends in the width direction of the electric wiring board 3A. When the mist adheres to the side surface 30a of the adhesive layer 30, the components of the mist permeate from the side surface 30a into the adhesive layer 30 and reach the wiring portion 6. As a result, electrical defects may occur due to corrosion of the wiring, etc.

[0038] On the other hand, in the liquid ejection head 1 of this embodiment, the side surfaces 30a of the adhesive layer 30 are covered with the first sealant 9 at both ends in the width direction of the electric wiring board 3, and the mist does not directly adhere to the side surfaces 30a of the adhesive layer 30. Since the components of the mist do not easily permeate the first sealant 9, it is possible to suppress the occurrence of electrical defects as described above.

[0039] In the liquid ejection head 100 of the comparative example, if the end faces of the widthwise ends of the electric wiring board 3A are covered with a sealant, it is possible to prevent the components of the mist from penetrating into the inside. However, the thickness of the electric wiring board 3A is about 0.1 mm to 0.3 mm, and it is difficult to apply a sealant to the end faces of such a thin electric wiring board 3A. Even if it were possible to apply a sealant to the end faces of the electric wiring board 3A, it is difficult to form a sealant layer with a sufficient thickness. Here, a sufficient thickness is a thickness that can prevent the components of the mist from penetrating into the inside.

[0040] In contrast, according to the liquid ejection head 1 of this embodiment, the width W2 of the second film 20 is narrower than the width W1 of the first film 21, and the second region 21b of the first film 21 is exposed before the first sealant 9 is applied. Using this exposed second region 21b, it is possible to cover the side surface 30a of the adhesive layer 30 with the first sealant 9 by utilizing the capillary phenomenon. The width of the second region 21b (=(W1-W2)÷2) is preferably, for example, 0.1 mm or more. With this width, it is possible to reliably cover the side surface 30a of the adhesive layer 30 with the first sealant 9.

[0041] Although the present invention has been specifically described above by way of an embodiment, the present invention is not limited to this embodiment, and various modifications are possible based on the technical concept of the present invention. 1(c), the wiring section 6 of the electric wiring board 3 has a single-layer structure, but is not limited thereto, and may have a multi-layer structure.

[0042] Fig. 7 is a diagram showing the configuration of an electric wiring board 3 in which the wiring portion 6 has a two-layer structure. Fig. 7(a) is a cross-sectional view of a first example of the electric wiring board 3, and Fig. 7(b) is a cross-sectional view of a second example of the electric wiring board 3. In Fig. 7(a) and Fig. 7(b), the X direction corresponds to the width direction, and the Z direction corresponds to the thickness direction.

[0043] The electric wiring board 3 of the first example shown in FIG. 7(a) further includes a third film 23 having at least a portion of a width W3 narrower than the width W1 of the first film 21. In this first example, the width W3 of the third film 23 is wider than the width W2 of the second film 20. The wiring portion 6 includes a first wiring portion 61 sandwiched between the first film 21 and the third film 23, and a second wiring portion 62 sandwiched between the third film 23 and the second film 20. The adhesive layer 30 includes a first adhesive layer 31 that bonds the first film 21 and the third film 23, and a second adhesive layer 32 that bonds the third film 23 and the second film 20. The first sealing material 9 covers a side surface 31a of the first adhesive layer 31 on the side of the second region 21b, and a side surface 32a of the second adhesive layer 32 on the side of the second region 21b.

[0044] According to the first example of the electric wiring board 3, the side surface 31a of the first adhesive layer 31 and the side surface 32a of the second adhesive layer 32 are covered with the first sealing material 9. Therefore, it is possible to suppress the components of the mist from penetrating into the inside of the first adhesive layer 31 and the second adhesive layer 32.

[0045] The electric wiring board 3 of the second example shown in Fig. 7(b) has basically the same configuration as the electric wiring board 3 of the first example shown in Fig. 7(a), but is different in the relationship of the widths of the first film 21, the second film 20, and the third film 23. In the electric wiring board 3 of the second example, the width W2 of the second film 20 is narrower than the width W1 of the first film 21, and the width W3 of the third film 23 is narrower than the width W2 of the second film 20.

[0046] In the electric wiring board 3 of the second example, the side surface 31a of the first adhesive layer 31 and the side surface 32a of the second adhesive layer 32 are also covered with the first sealing material 9. Therefore, it is possible to suppress the components of the mist from penetrating into the first adhesive layer 31 and the second adhesive layer 32.

[0047] In addition, since the first sealing material 9 is partially sandwiched between the end of the first film 21 and the end of the second film 20, a strong force acts to hold the first sealing material 9 between the first film 21 and the second film 20. Therefore, even if the electric wiring board 3 of the second example cannot be held in a horizontal position during the sealing material application process, the first sealing material 9 can be held between the end of the first film 21 and the end of the second film 20.

[0048] In the electric wiring board 3 of the first and second examples described above, three or more wiring layers (four or more film layers) can be applied, and in either case, the above-mentioned effects can be obtained.

[0049] Furthermore, in the liquid ejection head 1 of the present embodiment, the second film 20 of the electric wiring board 3 may be modified into any shape as long as the penetration of the mist components can be suppressed. Fig. 8 is a schematic diagram showing modified shapes of the second film 20 of the electric wiring board 3. Fig. 8(a) is a top view of a first modified example, Fig. 8(b) is a top view of a second modified example, and Fig. 8(c) is a top view of a third modified example. In Fig. 8(a), Fig. 8(b), and Fig. 8(c), the X direction indicates the width direction, and the Y direction indicates the longitudinal direction.

[0050] 8(a), the width of the center portion of the second film 20 in the Y direction is the same as that of the first film 21, and the widths of the portions adjacent to both sides of this center portion are narrower than the width of the first film 21. The second regions 21b of the first film 21 are located at both ends in the X direction, and two second regions 21b are arranged in the Y direction at each end.

[0051] According to the first modified example, the second region 21b can be used to apply the sealant, and the penetration of mist components can be suppressed in the region to which the sealant is applied. Generally, the closer to the recording element substrate 2 of the electric wiring substrate 3, the more likely it is that mist will adhere to the region. In the first modified example, the second region 21b is located in a region close to the recording element substrate 2 at both ends of the electric wiring substrate 3 in the X direction. This allows the region where the mist is likely to adhere to be covered with the sealant, and effectively suppresses the penetration of mist components.

[0052] In addition, by making the width of the central portion in the Y direction of second film 20 the same as the width of first film 21, the rigidity of electric wiring board 3 can be increased. In addition, a plurality of second regions 21b may be provided in the Y direction (three or more second regions 21b may be provided).

[0053] 8(b), the width of the second film 20 is narrower than the width of the first film 21 over the entire Y direction. The second region 21b of the first film 21 is located at one end in the X direction. The second region 21b extends over the entire Y direction.

[0054] According to the second modification, the sealant can be applied using the second region 21b, and the penetration of the mist components can be suppressed in the region where the sealant is applied. The sealing structure of the second modification is effective when there is a high possibility that the mist will adhere to one of the two ends in the X direction of the electric wiring board 3. In addition, by providing the second region 21b only on one side, the rigidity of the electric wiring board 3 can be increased compared to a structure in which the second region 21b is provided on both sides.

[0055] In a third modified example shown in FIG. 8(c), the second film 20 has a shape in which the width decreases from one end to the other end in the Y direction. The second regions 21b of the first film 21 are located at both ends in the X direction. The second regions 21b at each end extend in the Y direction and have a shape in which the width decreases from one end to the other end in the Y direction. The width of the second regions 21b becomes wider the closer they are to the recording element substrate 2.

[0056] According to the third modification, the sealant can be applied using the second region 21b, and the penetration of the mist components can be suppressed in the region where the sealant is applied. The sealing structure of the third modification is effective in cases where the closer to the recording element substrate 2 the more likely the mist will adhere to the region. In addition, since the second region 21b has a shape in which the width decreases from one end to the other end, the sealant can be poured from the wider side to the narrower side by capillary action. In this way, the sealant can be applied to the narrowed portion of the second region 21b by utilizing the capillary action.

[0057] In the above-mentioned first to third modified examples, the structures of two or more modified examples may be combined. For example, the first modified example may be combined with the second modified example. In this case, a plurality of second regions 21b are arranged at one end. Also, the first modified example may be combined with the third modified example. In this case, each second region 21b has a shape in which the width decreases from one end to the other end. Furthermore, the first modified example may be combined with the second and third modified examples. In this case, a plurality of second regions 21b are arranged at one end, and each second region 21b has a shape in which the width decreases from one end to the other end.

[0058] Furthermore, in the liquid ejection head 1 of this embodiment, the sealant applied to the second region 21b may be either the first sealant 9 or the second sealant 10, or may be a sealant different from these sealants 9 and 10. If the sealing material applied to the second region 21b is the first sealing material 9, then it is possible to apply the first sealing material 9 to both widthwise ends of the electric wiring board 3 and the electrical connection parts 70 in a single process, as shown in Fig. 4. If the sealing material applied to the second region 21b is the second sealing material 10, then it is possible to apply the second sealing material 10 to both widthwise ends of the electric wiring board 3 and the electrical connection parts 70 in a single process.

[0059] The application of the sealing material to the second region 21b may be performed in the manufacturing process of the electric wiring board 3 shown in Fig. 5. In this case, in the electric wiring board 3 separated in Fig. 5(h), the sealing material is applied using the second region 21b, so that the side surface 30a of the adhesive layer 30 is covered with the sealing material.

[0060] It is also possible to apply a sealant to the second region 21b after electrically connecting the electric wiring board 3 to the recording element board 2 and the control board. However, there are cases where a sufficient space for placing the dispenser needle cannot be secured above the second region 21b. In this case, it is preferable to use an electric wiring board 3 having a shape of the second film 20 that can be poured from one end of the second region 21b by utilizing the capillary phenomenon.

[0061] Disclosure of embodiments of the present invention includes the following configurations and methods. (Configuration 1) A liquid ejection head comprising: a recording element substrate having an ejection port for ejecting liquid; and an electric wiring substrate having a wiring portion, one end of which is electrically connected to the recording element substrate via an electric connection portion, the electrical wiring board includes a first film, a second film facing the wiring portion and having at least a portion of a width narrower than a width of the first film, and an adhesive layer bonding the first film and the second film together; A liquid ejection head, wherein the first film has a first region in contact with the adhesive layer and a second region located outside the first region in the width direction, and the side of the adhesive layer facing the second region is covered with a sealant. (Configuration 2) 2. The liquid ejection head according to claim 1, wherein the wiring portion extends in a longitudinal direction of the electric wiring board. (Configuration 3) 3. The liquid ejection head according to configuration 1 or 2, wherein the second region extends in the longitudinal direction of the electrical wiring board. (Configuration 4) 4. The liquid ejection head according to configuration 3, wherein the second region is provided over the entire area of ​​the electric wiring board in the longitudinal direction. (Configuration 5) 4. The liquid ejection head according to configuration 3, wherein the second region has a shape whose width decreases from one end to the other end in the longitudinal direction. (Configuration 6) 3. The liquid ejection head according to configuration 1 or 2, wherein the second region is provided in a plurality of regions in the longitudinal direction of the electric wiring board. (Configuration 7) The liquid ejection head according to any one of configurations 1 to 6, wherein the second region is provided on both sides of the first region in the width direction. (Configuration 8) A liquid ejection head according to configuration 1 or 2, wherein the second film has a narrow portion and a wide portion in the longitudinal direction of the electrical wiring board, and the narrow portion is located on the side of the recording element board. (Configuration 9) The electrical wiring board further includes a third film having at least a portion of a width narrower than a width of the first film, the wiring portion includes a first wiring portion sandwiched between the first film and the third film, and a second wiring portion sandwiched between the third film and the second film, the adhesive layer includes a first adhesive layer that adheres the first film and the third film to each other, and a second adhesive layer that adheres the third film and the second film to each other; A liquid ejection head described in any one of configurations 1 to 8, wherein the sealing material covers a side surface of the first adhesive layer facing the second region and a side surface of the second adhesive layer facing the second region. (Configuration 10) A liquid ejection head as described in configuration 9, wherein the width of at least a portion of the third film is wider than the width of at least a portion of the second film, and an end face of the third film is positioned outer than the end face of the second film in the width direction. (Configuration 11) A liquid ejection head as described in configuration 9, wherein the width of at least a portion of the third film is narrower than the width of at least a portion of the second film, and an end face of the second film is positioned outer than an end face of the third film in the width direction. (Configuration 12) A liquid ejection head described in any one of configurations 1 to 11, wherein the electrical connection portion includes a wire that connects a terminal of the recording element substrate and one end of the wiring portion, the sealant is filled below the wire, and another sealant having a higher viscosity than the sealant is provided on top of the sealant so as to cover the wire. (Configuration 13) A liquid ejection head comprising: a recording element substrate having an ejection port for ejecting liquid; and an electric wiring substrate having a wiring portion, one end of which is electrically connected to the recording element substrate via an electric connection portion, the electrical wiring board includes a first film, a second film facing the wiring portion and having at least a portion of a width narrower than a width of the first film, and an adhesive layer bonding the first film and the second film together; A liquid ejection head in which, in the width direction, an end of the first film is located outside the end of the narrowed portion of the second film, and at the outer end, the side of the adhesive layer is covered with a sealant. (Method 1) preparing an electric wiring board in which a first film and a second film, at least a portion of which has a width narrower than that of the first film, are fixed with an adhesive in a state in which a wiring portion is sandwiched between the first film and the second film; a step of electrically connecting a recording element substrate having an ejection port for ejecting liquid to one end of the wiring portion via an electrical connection portion, A method for manufacturing a liquid ejection head, comprising the steps of providing the first film with a first region that contacts an adhesive layer made of the adhesive and a second region that is positioned outboard of the first region in the width direction, and covering the side of the adhesive layer facing the second region with a sealant. (Method 2) A method for manufacturing a liquid ejection head according to method 1, comprising the steps of electrically connecting a terminal of the recording element substrate and one end of the wiring portion with a wire to form the electrical connection portion, filling the sealant below the wire, and applying another sealant having a higher viscosity than the sealant on top of the sealant to cover the wire. (Method 3) The method for manufacturing a liquid ejection head according to method 1 or 2, wherein the sealant is applied to a corner portion defined by the second region and the side surface of the adhesive layer by utilizing capillary action. [Explanation of symbols]

[0062] 1 Liquid ejection head 2. Recording element board 3 Electrical wiring board 9 First sealing material 20. Second Film 21 First Film 21a First Area 21b The second area 30 Adhesive layer

Claims

1. A liquid ejection head comprising: a recording element substrate having an ejection port for ejecting liquid; and an electric wiring substrate having a wiring portion, one end of which is electrically connected to the recording element substrate via an electric connection portion, the electrical wiring board includes a first film, a second film facing the wiring portion and having at least a portion of a width narrower than a width of the first film, and an adhesive layer bonding the first film and the second film together; A liquid ejection head, wherein the first film has a first region in contact with the adhesive layer and a second region located outside the first region in the width direction, and the side of the adhesive layer facing the second region is covered with a sealing material.

2. The liquid ejection head according to claim 1 , wherein the wiring portion extends in a longitudinal direction of the electric wiring board.

3. The liquid ejection head according to claim 1 , wherein the second region extends in a longitudinal direction of the electrical wiring board.

4. The liquid ejection head according to claim 3 , wherein the second region is provided over the entire area of ​​the electric wiring board in the longitudinal direction.

5. The liquid ejection head according to claim 3 , wherein the second region has a shape whose width decreases from one end to the other end in the longitudinal direction.

6. The liquid ejection head according to claim 1 , wherein the second region is provided in a plurality of regions in the longitudinal direction of the electric wiring board.

7. The liquid ejection head according to claim 1 , wherein the second region is provided on both sides of the first region in the width direction.

8. 2. The liquid ejection head according to claim 1, wherein the second film has the narrow portion and the wide portion in the longitudinal direction of the electric wiring board, and the narrow portion is located on the recording element board side.

9. The electrical wiring board further includes a third film having at least a portion of a width narrower than a width of the first film, the wiring portion includes a first wiring portion sandwiched between the first film and the third film, and a second wiring portion sandwiched between the third film and the second film, the adhesive layer includes a first adhesive layer that adheres the first film and the third film to each other, and a second adhesive layer that adheres the third film and the second film to each other; The liquid ejection head according to claim 1 , wherein the sealant covers a side surface of the first adhesive layer on the side of the second region and a side surface of the second adhesive layer on the side of the second region.

10. A liquid ejection head as described in claim 9, wherein the width of at least a portion of the third film is wider than the width of at least a portion of the second film, and an end face of the third film is positioned outer than an end face of the second film in the width direction.

11. A liquid ejection head as described in claim 9, wherein the width of at least a portion of the third film is narrower than the width of at least a portion of the second film, and an end face of the second film is positioned outer than an end face of the third film in the width direction.

12. 2. The liquid ejection head of claim 1, wherein the electrical connection portion includes a wire that connects a terminal of the recording element substrate and one end of the wiring portion, the sealant is filled below the wire, and another sealant having a higher viscosity than the sealant is provided on top of the sealant so as to cover the wire.

13. A liquid ejection head comprising: a recording element substrate having an ejection port for ejecting liquid; and an electric wiring substrate having a wiring portion, one end of which is electrically connected to the recording element substrate via an electric connection portion, the electrical wiring board includes a first film, a second film facing the wiring portion and having at least a portion of a width narrower than a width of the first film, and an adhesive layer bonding the first film and the second film together; A liquid ejection head in which, in the width direction, an end of the first film is located outside the end of the narrowed portion of the second film, and at the outer end, the side of the adhesive layer is covered with a sealant.

14. preparing an electric wiring board in which a first film and a second film, at least a portion of which has a width narrower than that of the first film, are fixed with an adhesive in a state in which a wiring portion is sandwiched between the first film and the second film; a step of electrically connecting a recording element substrate having an ejection port for ejecting liquid to one end of the wiring portion via an electrical connection portion, A method for manufacturing a liquid ejection head, comprising the steps of providing the first film with a first region that contacts an adhesive layer made of the adhesive and a second region that is positioned outside the first region in the width direction, and covering a side of the adhesive layer facing the second region with a sealant.

15. 15. The method for manufacturing a liquid ejection head according to claim 14, further comprising the steps of: electrically connecting a terminal of the recording element substrate and one end of the wiring portion with a wire to form the electrical connection portion; filling the sealant below the wire; and applying another sealant having a higher viscosity than the sealant on top of the sealant to cover the wire.

16. The method for manufacturing a liquid ejection head according to claim 14 or 15, wherein the sealant is applied to a corner portion defined by the second region and the side surface of the adhesive layer by utilizing capillary action.

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