JP7001373B2 - Liquid discharge head and its manufacturing method - Google Patents

Description

The present invention relates to a liquid discharge head that discharges a liquid and a method for manufacturing the same.

The liquid discharge head that discharges liquid for image recording, etc. has a discharge port located at a position facing the energy generating element, and discharges the liquid from the discharge port to the outside by the energy generated by the energy generating element. be. Such a liquid discharge head is called a side shooter type liquid discharge head. The liquid discharge head is generally located away from the element substrate with the energy generating element, the electrical wiring board with the electrical wiring, the support member supporting the element substrate and the electrical wiring board, and the support member. It has an internal board. One end of the electrical wiring board is connected to the element board, and the other end is connected to the internal board. Therefore, the electric power and the electric signal transmitted from the main body of the liquid discharge head to the internal substrate of the liquid discharge head are transmitted from the internal substrate to the energy generating element of the element substrate via the electric wiring board.

The electrical wiring board and the internal board are generally electrically connected by an anisotropic conductive film or wire bonding. When the electrical wiring board and the internal substrate are electrically connected by an anisotropic conductive film, the electrical pad of the electrical wiring board and the electrical pad of the internal substrate should be aligned between the two electrical pads. An anisotropic conductive film is placed and crimped together. When the electric wiring board and the internal board are electrically connected by wire bonding, for example, the electric pads are connected to each other by a bonding wire in a state where the electric wiring board is bonded on the internal board.

The electrical connection between the electrical wiring board and the internal substrate needs to be insulated and protected so that it does not come into contact with liquid in order to prevent electrical short circuits and corrosion. As a general insulation protection method, as described in Patent Document 1, a curable liquid sealing resin is applied to and around the electrical connection portion and cured, and the electrical connection portion is embedded in the sealing resin. There is a way to wrap it. Examples of the liquid sealing resin used here include epoxy resin, acrylic resin, urethane resin, silicon resin and the like having thermosetting property, UV curing property, and moisture curing property. Insulation protection from the recording liquid is achieved by embedding the electrical connection portion by the anisotropic conductive film or wire bonding with these sealing resins. For reliable insulation protection, it is preferable to widely apply the sealing resin not only to the electrical connection portion but also to the periphery thereof. That is, unless the portion where the liquid or the like may enter the electrical connection portion is sealed with the sealing resin, the recording liquid or the like cannot be sufficiently prevented from entering the electrical connection portion.

Japanese Unexamined Patent Publication No. 2007-313831

In order to apply the sealing resin not only to the electrical connection part but also to the surrounding area, the sealing resin is applied while the electrical wiring board and the internal board are electrically connected and rotated in various postures. Need to be applied. However, it is not easy to apply the coating while changing the postures of the electric wiring board and the internal board in the connected state. In addition, the time required for applying the sealing resin is long, and the lead time of the liquid discharge head is long. Further, a complicated mechanism is required to rotate the electric wiring board and the internal board, which increases the manufacturing cost of the liquid discharge head.

Therefore, an object of the present invention is to provide a liquid discharge head which can apply a sealing resin by a simple method at low cost and in a short time and has high reliability of insulation protection of an electrical connection portion and a method for manufacturing the same. It is in.

The liquid discharge head of the present invention includes a first electric wiring board, an element board having a discharge port for discharging liquid and electrically connected to one end of the first electric wiring board, and first electricity. It has a second electrical wiring board that is electrically connected to the other end of the wiring board, and the other end of the first electrical wiring board and the second electrical wiring board are connected to each other via an adhesive member. The adhesive member is joined, and the adhesive member is outward from the end of the joint portion of the first electric wiring board with the second electric wiring board when viewed in a direction orthogonal to the plate surface of the second electric wiring board. An electric pad is formed on the surface of the second electric wiring board having a joint portion with the first electric wiring board, which has a planar shape including an end portion located so as to protrude from the first electric wiring board. An electric pad is formed on a surface opposite to the surface facing the second electric wiring board, and the electric pad of the second electric wiring board and the electric pad of the first electric wiring board are electrically connected to each other. The adhesive member is located between the region where the electric pad of the first electric wiring board is formed and the second electric wiring board when viewed in a direction orthogonal to the plate surface of the second electric wiring board. ..

According to the present invention, the sealing resin can be applied by a simple method at low cost and in a short time, and a liquid discharge head having high reliability of insulation protection of the electrical connection portion is realized.

It is a perspective view and the plan view of the main part of the liquid discharge head of 1st Embodiment of this invention. FIG. 1 is a plan view and a cross-sectional view of the periphery of the joint portion between the electrical wiring board and the internal board of the liquid discharge head shown in FIG. 1, and is a cross-sectional view of a comparative example. It is a perspective view which shows a part of the manufacturing method of the liquid discharge head shown in FIG. It is sectional drawing around the joint part of the electric wiring board and the internal board of 2nd Embodiment. It is a top view around the joint portion of the electric wiring board and the internal board of 3rd Embodiment. It is a perspective view of the main part of the liquid discharge head of 4th Embodiment, the plan view of the periphery of the joint part of the electric wiring board and the internal board, and the plan view of the modified example thereof.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1A is a perspective view showing a main part of the liquid discharge head according to the present invention, and FIG. 1B is a plan view thereof. FIG. 2A is a plan view of the periphery of the joint portion between the electrical wiring board and the internal substrate and the electrical connection portion of FIG. 1B. FIG. 2B is a plan view showing a state in which the electrical connection portion shown in FIG. 2A is covered with a sealing resin. FIG. 2 (c) is a cross-sectional view taken along the line AA of FIG. 2 (a). FIG. 2D is a cross-sectional view of a comparative example for comparison with the configuration shown in FIG. 2C.
As shown in FIGS. 1 (a) and 1 (b), the liquid discharge head of the present embodiment includes an element substrate (liquid discharge chip) 101, an electric wiring board (first electric wiring board) 102, and a support member. It has 103 and an internal board (second electrical wiring board) 105 which is another board. The element substrate 101 includes a discharge port 101a for discharging a liquid such as a recording liquid (liquid ink) and an energy generating element (for example, a heat generating element, a piezoelectric element, etc.) arranged in a pressure chamber communicating with the discharge port (not shown). It is equipped with. The support member 103 supports one end of the element substrate 101 and the electrical wiring board 102. The internal substrate 105 is arranged at a position away from the support member 103. The electrical wiring board 102 has an electrical wiring (not shown) having one end connected to the element substrate 101 and the other end electrically connected to the internal substrate 105.

In this liquid discharge head, one end of the element substrate 101 and the electric wiring board 102 is joined on the support member 103. In the example shown in FIG. 1A, one end of the element substrate 101 and the electric wiring board 102 is electrically connected by wire bonding or the like (not shown), and is covered with a sealing resin 104 from above. Further, the other end of the electrical wiring board 102 is joined to the internal board 105. In the example shown in FIG. 1 (b), the electric pad 107 at the other end of the electric wiring board 102 is electrically connected to the electric pad 112 of the internal board 105 by the bonding wire 108. However, the method of electrically connecting the element substrate 101 and the electrical wiring board 102 and the method of electrically connecting the internal substrate 105 and the electrical wiring board 102 are not limited to wire bonding. A known connection method using a flying lead, an anisotropic conductive film, an anisotropic conductive paste, or the like may be adopted to electrically connect them.

The electrical connection between the electrical wiring board 102 and the element board 101, and the electrical connection between the electrical wiring board 102 and the internal board 105 need to be insulated and protected against the recording liquid, moisture (humidity) in the air, and the like. Generally, these electrical connections are insulated and protected by being coated with a curable liquid sealing resin and solidified. 1A and 1B show a sealing resin 104 that protects the electrical connection between the electrical wiring board 102 and the element substrate 101, and a seal that protects the electrical connection between the electrical wiring board 102 and the internal substrate 105. The stop resin 109 is shown. However, in order to illustrate the configuration around the joint portion between the electrical wiring board 102 and the internal board 105, which is one of the features of the present invention described later, in FIG. 1B, the sealing resin 109 is a two-dot chain line and has only a contour. It is shown. Examples of the sealing resins 104 and 109 covering the electrical connection portion include epoxy resin, acrylic resin, epoxy acrylate resin, imide resin, and amide resin. The curing method of the sealing resins 104 and 109 may be any of two-component mixed curing in which a curing agent is mixed, thermosetting by heating, UV curing by ultraviolet irradiation, and the like, and the characteristics of the sealing resins 104 and 109. A wide variety of curing methods can be adopted according to the situation. A particularly preferable and generally used liquid sealing resin is a thermosetting epoxy resin.

One end of the electric wiring board 102 and the element board 101 are adhered to each other on the support member 103 with an adhesive (not shown). On the other hand, the other end of the electrical wiring board 102 is bonded to the internal board 105 by an adhesive film 106 which is an example of an adhesive member. Examples of the adhesive film 106 include a film made of a curable resin composition and a film that exerts an adhesive force by plastic deformation. Specifically, an adhesive film 106 made of a resin composition containing an epoxy resin, an imide resin, an amide resin, an acrylic resin, a urethane resin, or the like can be used. The adhesive film 106 may have adhesiveness from the beginning or may be heated to develop adhesiveness. Considering the ease of handling of the adhesive film 106, a film of a type that does not have adhesiveness at room temperature and exhibits adhesiveness when heated is convenient. As a method of joining the electric wiring board 102 and the internal board 105, a method of using an adhesive or double-sided tape in addition to the adhesive film 106 can be considered. Among these joining methods, joining with an adhesive film or double-sided tape is convenient in consideration of the ease of the joining process. Of these, double-sided tape is generally commercially available and inexpensive, but many of them are inferior in ink resistance. In particular, since the liquid ejection head is required to have resistance to the ejected liquid (for example, liquid ink for recording), it is often preferable to use an adhesive film 106 of a type that exhibits adhesiveness by heating rather than a commercially available double-sided tape. ..
As an example, in the liquid discharge head of the present embodiment, the other end of the electric wiring board 102 is bonded to the inner board 105 via an adhesive film 106 made of a resin composition containing an epoxy resin. The adhesive film 106 does not have adhesiveness at room temperature, and exhibits adhesiveness when heated and pressurized to adhere to the adherend, and further heated to strengthen the adhesive force. Specific examples of the adhesive film 106 include FB-ML80 and FB-ML4 (both are trade names) manufactured by Nitto Denko KK, and FB-ML4 is used in this embodiment.

As described above, in the present embodiment, the adhesive film 106 is interposed between the electric wiring board 102 and the internal board 105 to bond the electric wiring board 102 and the internal board 105. Then, the adhesive film 106 is viewed in a direction (Z direction) orthogonal to the plate surface (main surface) of the internal substrate 105 (viewed in a plane), and the end of the joint portion of the electrical wiring board 102 with the internal substrate 105. It has a planar shape including an end portion located outside the portion. Specifically, in the width direction (X direction), both end portions 106a and 106b of the adhesive film 106 protrude outward from both end portions 102a and 102b of the joint portion of the electrical wiring board 102 with the internal substrate 105. is doing. That is, when viewed in the direction orthogonal to the plate surface of the internal substrate 105, the length in the width direction of the adhesive film 106 is larger than the length in the width direction of the electrical wiring substrate 102. The width direction referred to here is a direction orthogonal to a direction extending from the central portion of the electric wiring board 102 toward the joint portion with the internal board 105 (for convenience, referred to as "the extending direction (Y direction) of the electric wiring board 102"). Is. The width direction is the left-right direction of FIGS. 1 (b) and 2 (a). The extending direction of the electric wiring board 102 is the vertical direction shown in FIGS. 1 (b) and 2 (a). Further, in the extending direction of the electrical wiring board 102, the tip portion 102c of the joint portion of the electrical wiring board 102 with the internal substrate 105 is located in the intermediate portion away from the end portion of the adhesive film 106, that is, the end portion 106c. It is located inside.

Since the adhesive film 106 is arranged in this way, the adhesive film 106 is not completely covered by the electric wiring board 102. The ends 106a to 106c of the adhesive film 106 are outside the three ends (the end portions 102a and 102b in the width direction and the end portions 102c on the joint portion side) of the portion joined to the inner substrate 105 of the electrical wiring board 102. Each is sticking out. In this way, with the electrical wiring board 102 bonded to the internal substrate 105 via the adhesive film 106, the electrical pad 107 of the electrical wiring board 102 and the electrical pad 112 of the internal substrate 105 are connected by the bonding wire 108. There is. The electrical connection portion is covered with the sealing resin 109 as shown in FIG. 2 (b). The adhesive film 106 is located between the region where the electric pad 107 of the electric wiring board 102 is formed and the internal board 105 when viewed in the direction orthogonal to the plate surface (Z direction).

By using such an adhesive film 106 and a sealing resin 109, it is possible to prevent liquids such as recording liquid from entering the electrical connection portion and effectively insulate and protect the electrical connection portion. This point will be described in detail below.
As shown in FIGS. 1 (a), 1 (b), and 2 (a), in the present embodiment, a part of the adhesive film 106 (the D portion and the E portion of FIG. 2 (a)) is viewed in a plan view. Projects out of the end of the electrical wiring board 102. According to this configuration, as is clear from FIG. 2 (c), which is a cross-sectional view taken along the line AA of FIG. 2 (a), there are no voids through which the liquid can enter. That is, there is no space between the electrical wiring board 102 and the internal board 105 to hold the liquid. Therefore, it is unlikely that the liquid will sneak into the joint portion (electrical connection portion) between the electrical wiring board 102 and the internal substrate 105.

Here, as shown in FIG. 2D, a comparative example in which the end portion of the adhesive film 106 does not protrude outside the end portion of the electrical wiring board 102 and is located inside the end portion of the electrical wiring board 102. To consider. In this comparative example, a gap B is formed between the electric wiring board 102 and the internal board 105 on the outside of the adhesive film 106. With a general sealing resin, due to the viscosity and fluidity, a sufficient amount of sealing resin that cannot penetrate into the narrow void B or completely fills the void B penetrates into the void B. It may not be possible. In such a case, the void B may remain unclosed even after the sealing resin 109 is applied. Then, for example, at the position corresponding to the portion C in FIG. 2B (the outer edge portion of the sealing resin 109), the liquid is guided to the gap B along the back surface of the electric wiring board 102. Then, the liquid accumulated in the gap B may reach the electrical connection portion between the electrical wiring board 102 and the internal substrate 105. Specifically, the liquid comes into contact with the electric pad 107 of the electric wiring board 102, the electric pad 112 of the internal board 105, and the bonding wire 108 extending between the electric pads 107 and 112, causing an electric short circuit or corrosion. There is a risk of causing it. On the other hand, in the present embodiment, as shown in FIGS. 2 (a) and 2 (c), the end portion of the adhesive film 106 protrudes outside the end portion of the electric wiring board 102, so that the electric wiring board 102 There is no void B between the internal substrates 105, and the liquid does not infiltrate and accumulate. Therefore, it is unlikely that the liquid will reach the electrical connection portion between the electrical wiring board 102 covered with the sealing resin 109 and the internal substrate 105 to cause a problem such as an electrical short circuit.
As described above, in the present embodiment, the end portion of the adhesive film 106 protrudes outside the end portion of the electrical wiring board 102. As a result, defects such as an electrical short circuit between the electric wiring board 102 and the internal board 105 due to the infiltration of the liquid into the sealing resin 109 are suppressed, and a highly reliable liquid discharge head for insulation protection can be obtained.

In the method for manufacturing a liquid discharge head of the present embodiment, a step of joining the electrical wiring board 102 to the internal board 105 using the adhesive film 106 will be described with reference to the perspective views of FIGS. 3 (a) to 3 (c). do. First, as shown in FIG. 3A, the adhesive film 106 formed to a predetermined size by cutting or punching is placed at a predetermined position on the inner substrate 105. A separator film 113 made of resin is prepared above the adhesive film 106 (position facing the surface not in contact with the internal substrate 105). Next, the heating tool 114 is lowered from above the separator film 113 to heat the separator film 113 and the adhesive film 106 and pressurize the inner substrate 105. As a result, the adhesive film 106 is fixed (thermocompression bonded) to the internal substrate 105. At this time, the separator film 113 prevents the heating tool 114 and the adhesive film 106 from adhering to each other.

As shown in FIG. 3B, the separator film 113 is removed, and the electrical wiring board 102 is placed on the adhesive film 106. Then, the heating tool 114 is lowered from above the electric wiring board 102 to heat the electric wiring board 102 and pressurize the adhesive film 106 and the internal board 105. As a result, the electrical wiring board 102 is thermocompression bonded to the adhesive film 106. In this way, the electrical wiring board 102 and the internal board 105 are joined via the adhesive film 106. As described above, in the present embodiment, the ends 106a to 106c of the adhesive film 106 protrude outward from the ends 102a to 102c of the electrical wiring board 102 below the wire bonding 108 which is the electrical connection portion. As a result, the adhesive area of the adhesive film 106 that contributes to the bonding between the electrical wiring substrate 102 and the internal substrate 105 is large, so that sufficient adhesive strength can be obtained.
An electric pad 112 is formed on the inner substrate 105 at a position outside the adhesive film 106. An electric pad 107 is formed on the surface of the electric wiring board 102 opposite to the surface facing the internal board 105. After the internal board 105 and the electric wiring board 102 are joined, as shown in FIG. 3C, the electric pad 107 of the electric wiring board 102 and the electric pad 112 of the internal board 105 are electrically connected by the bonding wire 108. ..

Next, in order to insulate and protect the wire bonding 108 and the electric pad 107, which are the electrical connection portions, a curable liquid sealing resin 109 is applied from above the electrical connection portion as shown in FIG. 2 (b). Cover the electrical connection. At this time, the liquid sealing resin 109 is applied so as to cover the entire adhesive film 106 protruding outward from the end portion of the electric wiring board 102. By applying in this way, the electrical connection portion can be effectively insulated and protected from the recording liquid or the like. In this way, the sealing resin 109 applied onto the electrical wiring board 102 including the electrical connection portion and the internal substrate 105 is cured.
On the other hand, although not described in detail, as shown in FIGS. 1 (a) and 1 (b), the end of the electrical wiring board 102 on the opposite side to the joint with the internal board 105 is provided with an adhesive (not shown). It is fixed on the support member 103. Further, the element substrate 101 having a large number of ejection ports 101a is fixed at a position close to the end portion of the electric wiring board 102 on the support member 103 by using an adhesive (not shown). Then, although not shown, the electric wiring board 102 and the element board 101 are electrically connected by wire bonding or the like. Further, a curable liquid sealing resin 104 is applied from above the electrical connection portion and cured so as to cover the electrical connection portion.

As described above, the end portion of the electrical wiring board 102 is electrically connected to the internal substrate 105, and the end portion on the opposite side thereof is electrically connected to the element substrate 101. In this way, the liquid discharge head of the present embodiment can be formed. In addition, in the above-mentioned step of electrically connecting the end portion of the electric wiring board 102 to the internal substrate 105 and the step of electrically connecting the end portion on the opposite side to the element substrate 101, which step is performed first. It doesn't matter.

[Second Embodiment]
In the second embodiment of the present invention, the adhesive film 106 used for joining the electrical wiring substrate 102 and the internal substrate 105 is made of a material that dissolves in a liquid sealing resin. Specifically, DF470 (trade name), which is a heat-adhesive film manufactured by Hitachi Kasei Co., Ltd., is used as the adhesive film 106. Further, as the sealing resin 109, CV5300 (trade name), which is a fluid liquid sealing resin having an epoxy resin composition manufactured by Panasonic Corporation, is used. Since the adhesive film 106 and the sealing resin 109 selected here have similar polarities, the adhesive film 106 is dissolved in the liquid sealing resin 109 during heating when the liquid sealing resin 109 is thermally cured, and the cured sealing is performed. The adhesive film 106 is incorporated into the waterproof resin 109. When the adhesive film 106 is melted and cured in a state of being incorporated into the liquid sealing resin 109 in this way, as shown in FIG. 4, the interface between the adhesive film 106 and the sealing resin 109 disappears and is integrated. It is possible to perform more reliable adhesion. In the present embodiment, the same configuration and method as in the first embodiment are adopted except that the materials constituting the adhesive film 106 and the sealing resin 109 are selected as described above.

[Third Embodiment]
The third embodiment of the present invention employs a configuration in which the insulation protection of the electrical connection portion can be achieved even when an error in the processing dimensions of the adhesive film 106 or a deviation in the attachment position occurs. Specifically, in the present embodiment, the same sealing resin 109 as in the first embodiment and the low-viscosity sealing resin (another sealing resin) 110 shown in the plan view of FIG. 5 are used in combination. There is. The sealing resin 110 is arranged between the inner substrate 105 and the sealing resin 109. Similar to FIG. 1 (b), in FIG. 5, only the outline of the sealing resin 109 is shown by a two-dot chain line. Its technical significance will be described below.
In the portion E or the like around the end of the electric wiring board 102 shown in FIG. 2A, due to an error in the processing dimensions of the adhesive film 106, a deviation in the sticking position, or the like, the portion E or the like is outside the end of the electric wiring board 102. It is conceivable that the end portion of the adhesive film 106 does not protrude. When the end portion of the adhesive film 106 does not protrude outside the end portion of the electrical wiring board 102, a gap B in which liquid can be collected is formed as in the state shown in FIG. 2 (d), and the electrical connection portion is formed. The reliability of insulation protection is low. Therefore, in the present embodiment, the low-viscosity sealing resin 110 shown in FIG. 5 is applied to the portion E (see FIG. 2A) around the end of the electrical wiring board 102, and FIG. 2D is shown. Even if the void B as shown is generated, the void B is filled with the low-viscosity sealing resin 110. Since the sealing resin 110 has a low viscosity, it easily gets wet and spreads due to the capillary force, and easily fills the void B. By filling the void B with the low-viscosity sealing resin 110, for example, the liquid presses the back surface of the electric wiring substrate 102 at the position corresponding to the C portion in FIG. 2B (the outer edge of the sealing resin 109). It is suppressed from penetrating into the inside of the sealing resin 109. That is, the liquid path leading from the side of the adhesive film 106 to the electrical connection portion can be blocked by the low-viscosity sealing resin 110 for sealing. The viscosity of the low-viscosity sealing resin 110 in the present embodiment is 0.1 to 100 Pa · s, more preferably about 1 to 80 Pa · s. As an example, an epoxy resin-based encapsulating resin having a viscosity of 10 Pa · s is used. In this way, after the low-viscosity sealing resin 110 shown in FIG. 5 is applied around the end portion of the electrical wiring board 102, the electrical wiring board 102 including the electrical connection portion is used as in the first embodiment. A liquid sealing resin 109 is applied onto the inner substrate 105 and cured. This embodiment is the same as that of the first embodiment except that the sealing resin 110 having a low viscosity is used.

[Fourth Embodiment]
The liquid discharge head of the present embodiment has a configuration having a plurality of element substrates (liquid discharge chips) 101. For example, as shown in the perspective view of FIG. 6A, the six element substrates 101 are bonded to the support member 103 by an adhesive in the same manner as the element substrate 101 of the first embodiment. Further, each support member 103 is joined to a part (base block) 111 of the housing of the head by an adhesive. Further, the other end of each of the electrical wiring boards 102 whose one end is supported on each support member 103 and connected to each element board 101 is joined to one long internal board 105. The bonding of the electric wiring board 102 to the internal board 105 is performed by using the adhesive film 106 as in the first embodiment.

FIG. 6B is an enlarged plan view of a joint portion between the electrical wiring board 102 and the internal board 105 in the present embodiment. As shown in FIG. 6B, the electrical wiring board 102 is bonded to the internal board 105 by the adhesive film 106 as in the first embodiment. However, in the portion F around the joint portion side end portion in the extending direction of the electric wiring board 102, the end portion of the adhesive film 106 does not protrude outside the end portion of the electric wiring board 102. This is to prevent the adhesive film 106 from spreading over the electric pad 112 of the internal board 105 when the electric wiring board 102 is crimped onto the internal board 105. Explaining this point, if the end portion of the adhesive film 106 protrudes outside the end portion of the electric wiring board 102 as in the first embodiment, sufficient adhesive force of the electric wiring board 102 can be obtained. .. However, depending on the material of the adhesive film 106 and the conditions at the time of thermocompression bonding, the adhesive film 106 softens during thermocompression bonding and spreads excessively on the surface of the electric wiring board 102 to cover a part of the electric pad 112 of the internal board 105. , May compromise the reliability of the electrical connection. Therefore, in the present embodiment, the adhesive film 106 is arranged so that the position of the joint portion side end portion 106c of the adhesive film 106 coincides with the position of the end portion 102c of the electric wiring board 102 in the extending direction of the electric wiring board 102. ing. However, the adhesive film 106 is always present at the lower part of the electric pad 107 of the electric wiring board 102 for wire bonding. This is because if the adhesive film 106 is not present in the lower part of the electric pad 107, a gap may be formed in the lower part of the electric pad 107 and wire bonding may not be performed satisfactorily. The adhesive film 106 may be arranged so that the joint-side end 106c of the adhesive film 106 is located inside the end 102c of the electric wiring board 102 in the extending direction of the electric wiring board 102.
After joining the plurality of electrical wiring boards 102 to one internal substrate 105, as in the first embodiment, on the electrical wiring board 102 including the electrical connection portion and the end portion of the internal substrate 105 and the adhesive film 106, A curable liquid sealing resin 109 is applied and cured. In this way, the liquid discharge head of the present embodiment having the six element substrates 101 is manufactured.

In the modified example of the present embodiment shown in FIG. 6C, the sealing resin 109 is applied so as to expose the end portion of the adhesive film 106 as in the portion G. By applying the sealing resin 109 in this way, it is possible to suppress the amount of the sealing resin 109 used. As long as the adhesive film 106 has sufficient adhesive strength, there is no problem even if a part of the adhesive film 106 is exposed in this way.

In a liquid recording head having a plurality of liquid discharge chips 101 as in the present embodiment, wire bonding is suitable as an electrical connection method for joining a plurality of electrical wiring boards 102 to one internal substrate 105. There is. Of course, electrical connection by ILB (Inner Lead Bonding), OLB (Outer Lead Bonding), or ACF (anisotropic conductive film) is also possible. However, when a plurality of electric wiring boards 102 are connected to one internal board 105, there is a possibility that the positional relationship between the electric pads 107 of each electric wiring board 102 and the electric pads 112 of the internal board 105 becomes large. If the positions of the electric pad 107 and the electric pad 112 are significantly deviated from each other, it may be impossible to electrically connect both electric pads by ILB or OLB. On the other hand, in the case of electrical connection by wire bonding, since it is possible to allow a slight positional deviation between the electric pad 107 and the electric pad 112, a configuration in which a plurality of electric wiring boards 102 are bonded to one internal board 105 in particular. Is suitable for.

As described above, according to the present invention, the risk of liquid such as a discharge liquid infiltrating into the electrical connection portion between the electrical wiring board 102 and the internal substrate 105 is reduced, and the occurrence of defects such as an electrical short circuit is suppressed. Can be done. This effect is that the end portion of the adhesive film 106 protrudes outside the end portion of the joint portion of the electrical wiring board 102 with the internal substrate 105 when viewed in a direction orthogonal to the plate surface of the internal substrate 105. Realized by. However, the configuration is not limited to the configuration in which all the ends of the adhesive film 106 protrude outside the end of the joint portion of the electrical wiring board 102 with the internal substrate 105. A certain effect can be obtained even if a part of the end portion of the adhesive film 106 protrudes outside the end portion of the joint portion of the electrical wiring board 102 with the internal substrate 105.
It is also possible to arbitrarily combine the respective configurations of the above-mentioned first to fourth embodiments.

101 Element substrate (liquid ejection chip)
102 Electrical wiring board 103 Support member 104 Encapsulating resin 105 Internal board 106 Adhesive film (adhesive member)
107 Electric pad (electrical connection)
108 Bonding wire (electrical connection)
109 Encapsulating resin 110 Low-viscosity encapsulating resin 112 Electric pad (electrical connection)

Claims (18)

A first electric wiring board, an element board having a discharge port for discharging liquid and electrically connected to one end of the first electric wiring board, and the other end of the first electric wiring board. With a second electrical wiring board, which is electrically connected to
The other end of the first electric wiring board and the second electric wiring board are joined via an adhesive member.
The adhesive member protrudes outward from the end of the joint portion of the first electric wiring board with the second electric wiring board when viewed in a direction orthogonal to the plate surface of the second electric wiring board. Has a planar shape that includes the edges that are located
An electric pad is formed on the surface of the second electric wiring board having a joint portion with the first electric wiring board, and the surface of the first electric wiring board facing the second electric wiring board. An electric pad is formed on the surface opposite to the electric pad, and the electric pad of the second electric wiring board and the electric pad of the first electric wiring board are electrically connected to each other.
When viewed in a direction orthogonal to the plate surface of the second electric wiring board, the adhesive member is formed between the region of the first electric wiring board on which the electric pad is formed and the second electric wiring board. Located , liquid discharge head. A first electric wiring board, an element board having a discharge port for discharging liquid and electrically connected to one end of the first electric wiring board, and the other end of the first electric wiring board. With a second electrical wiring board, which is electrically connected to
The other end of the first electric wiring board and the second electric wiring board are joined via an adhesive member.
The adhesive member protrudes outward from the end of the joint portion of the first electric wiring board with the second electric wiring board when viewed in a direction orthogonal to the plate surface of the second electric wiring board. Has a planar shape that includes the edges that are located
An electric pad is formed on the surface of the second electric wiring board having a joint portion with the first electric wiring board, and the surface of the first electric wiring board facing the second electric wiring board. An electric pad is formed on the surface opposite to the electric pad, and the electric pad of the second electric wiring board and the electric pad of the first electric wiring board are electrically connected to each other.
The end of the adhesive member located outside the end of the joint portion of the first electric wiring board with the second electric wiring board, the electric pad of the second electric wiring board, and the first. A liquid discharge head further comprising a sealing resin covering the electrical connection portion of the electrical wiring board with the electrical pad. In the width direction orthogonal to the direction extending from the central portion of the first electrical wiring board toward the joint with the second electrical wiring board, both ends of the adhesive member are the first electrical wiring board. The liquid discharge head according to claim 1 or 2 , which is located so as to protrude outward from both ends of the joint portion with the second electric wiring board. The position of the end of the adhesive member is the tip of the first electrical wiring board in the direction extending from the central portion of the first electrical wiring board toward the joint with the second electrical wiring board. The liquid discharge head according to any one of claims 1 to 3, which coincides with the position or is inside the tip portion of the first electrical wiring board . The liquid according to any one of claims 1 to 4, wherein the electric pad of the second electric wiring board and the electric pad of the first electric wiring board are electrically connected by wire bonding. Discharge head. When viewed in a direction orthogonal to the plate surface of the second electric wiring board, the adhesive member is formed between the region of the first electric wiring board on which the electric pad is formed and the second electric wiring board. The liquid discharge head according to claim 2 , which is located. Another sealing resin is provided at a portion of the end portion of the joint portion of the first electric wiring board with the second electric wiring board, in which a part of the adhesive member does not protrude to the outside. , The liquid discharge head according to claim 2 or 6 . The liquid discharge head according to claim 7 , wherein the other sealing resin has a lower viscosity than the sealing resin. The liquid discharge head according to claim 7 or 8 , wherein the viscosity of the other sealing resin is 0.1 to 100 Pa · s. The liquid discharge head according to any one of claims 2, 6 to 9 , wherein the adhesive member melts into the sealing resin and is integrated. The liquid discharge head according to any one of claims 1 to 10 , wherein the adhesive member is an adhesive film that develops adhesiveness by heating. The liquid discharge head according to any one of claims 1 to 11 , further comprising a sealing resin that covers an electric connection portion between the first electric wiring board and the element board. A first electric wiring board, an element board having a discharge port for discharging liquid and electrically connected to one end of the first electric wiring board, and the other end of the first electric wiring board. A method of manufacturing a liquid discharge head having a second electrical wiring board electrically connected to and.
A step of joining the other end of the first electric wiring board and the second electric wiring board via an adhesive member,
The electric pad formed on the surface of the second electric wiring board having a joint portion with the first electric wiring board and the second electric wiring board of the first electric wiring board face each other. It comprises a step of electrically connecting an electric pad formed on a surface opposite to the surface and electrically connecting the first electric wiring board and the second electric wiring board.
In the step of joining the other end of the first electric wiring board and the second electric wiring board, a part of the adhesive member when viewed in a direction orthogonal to the plate surface of the second electric wiring board. Is located so as to protrude outside the end of the joint portion of the first electric wiring board with the second electric wiring board , and is viewed in a direction orthogonal to the plate surface of the second electric wiring board. The first electric wiring board and the second electric wiring so that the adhesive member is located between the region where the electric pad is formed and the second electric wiring board of the first electric wiring board. A method for manufacturing a liquid discharge head that joins a substrate. A first electric wiring board, an element board having a discharge port for discharging liquid and electrically connected to one end of the first electric wiring board, and the other end of the first electric wiring board. A method of manufacturing a liquid discharge head having a second electrical wiring board electrically connected to and.
A step of joining the other end of the first electric wiring board and the second electric wiring board via an adhesive member,
The electric pad formed on the surface of the second electric wiring board having a joint portion with the first electric wiring board and the second electric wiring board of the first electric wiring board face each other. It comprises a step of electrically connecting an electric pad formed on a surface opposite to the surface and electrically connecting the first electric wiring board and the second electric wiring board.
In the step of joining the other end of the first electric wiring board and the second electric wiring board, one of the adhesive members is viewed in a direction orthogonal to the plate surface of the second electric wiring board. The first electric wiring board and the second electric wiring board so that the portion protrudes outside the end portion of the joint portion of the first electric wiring board with the second electric wiring board. Join with
The end of the adhesive member located outside the end of the joint portion of the first electric wiring board with the second electric wiring board , the electric pad of the second electric wiring board, and the first. A method for manufacturing a liquid discharge head, further comprising a step of applying a liquid sealing resin so as to cover an electric connection portion of the electric wiring board with the electric pad , and then curing the liquid. The method for manufacturing a liquid discharge head according to claim 13 , further comprising a step of electrically connecting the first electric wiring board to the element board. The production of the liquid discharge head according to claim 15 , further comprising a step of applying a liquid sealing resin so as to cover the electrical connection portion between the first electric wiring board and the element board, and then curing the liquid. Method. In the step of joining the other end of the first electric wiring board and the second electric wiring board, the joining portion of the first electric wiring board from the central portion to the second electric wiring board. In the width direction orthogonal to the direction extending toward, both ends of the adhesive member protrude outward from both ends of the joint portion of the first electric wiring board with the second electric wiring board. The method for manufacturing a liquid discharge head according to any one of claims 13 to 16, wherein the first electric wiring board and the second electric wiring board are joined to each other. In the step of joining the other end of the first electric wiring board and the second electric wiring board, the joining portion of the first electric wiring board from the central portion to the second electric wiring board. The position of the end portion of the adhesive member coincides with the position of the tip portion of the first electric wiring board in the direction extending toward, or is inside the tip portion of the first electric wiring board. The method for manufacturing a liquid discharge head according to any one of claims 13 to 17, wherein the first electric wiring board and the second electric wiring board are joined as described above.

Images