Two-color molded product and method for manufacturing a two-color molded product

Abstract

To provide a two-color molded product in which deformation and distortion during secondary molding are suppressed. [Solution] A two-color molded product having a primary molded product and a secondary molded product, wherein the primary molded product has a ring shape into which other members can be inserted, and the secondary molded product has a cylindrical portion that supports the primary molded product, the cylindrical portion comprising a first support portion that supports the primary molded product from around the ring shape, and a second support portion that supports the first molded product from a direction intersecting the direction in which the first support portion supports it, characterized in that the thickness of the first support portion in the direction in which the primary molded product is supported is smaller than the thickness of the second support portion in the direction in which the primary molded product is supported.

Description

Technical Field

[0001] The present invention relates to a two-color molded product and a method for manufacturing the same.

Background Art

[0002] Generally, a two-color molded product is formed by molding a primary molded product using a mold and a movable mold, and then clamping the movable mold holding the primary molded product and a secondary molding mold, and injecting a secondary molding resin into the secondary molding mold.

[0003] In Patent Document 1, a configuration is disclosed in which a deformation portion for absorbing stress acting on a primary molded product is formed, thereby reducing deformation and distortion of the primary molded product due to the injection pressure of secondary molding.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the configuration of Patent Document 1, when the secondary molding resin contacts the primary molded product, the surface of the primary molded product is affected by the temperature of the secondary molding resin and may remelt. In this case, a part of the remelted primary molded product is deformed along the flow direction of the secondary molding resin, and when it is cooled and cured again, deformation and distortion in the same direction as the flow direction occur in the primary molded product.

[0006] Therefore, an object of the present disclosure is to provide a two-color molded product in which deformation and distortion in secondary molding are suppressed.

Means for Solving the Problems

[0007] A two-color molded product according to one aspect of the present disclosure is a two-color molded product having a primary molded product and a secondary molded product, wherein the primary molded product has a ring shape into which other members can be inserted, and the secondary molded product has a cylindrical portion that supports the primary molded product, the cylindrical portion comprising a first support portion that supports the primary molded product from around the ring shape, and a second support portion that supports the first molded product from a direction intersecting the direction in which the first support portion supports it, wherein the thickness of the first support portion in the direction in which the primary molded product is supported is smaller than the thickness of the second support portion in the direction in which the primary molded product is supported. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a two-color molded product in which deformation and distortion during secondary molding are suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] Exploded perspective view of the liquid dispensing head [Figure 2] Cross-sectional view of the circulation unit [Figure 3] Schematic diagram of connecting parts in two-color molding. [Figure 4] Cross-sectional view of the connecting component during primary resin inflow according to the embodiment of this disclosure [Figure 5] Top view of the connecting component during primary resin inflow according to the embodiment of this disclosure [Figure 6] Cross-sectional view of body parts and connecting parts when secondary resin is inflow in the comparative example. [Figure 7] Top view of body and connecting parts during secondary resin inflow in comparative example [Figure 8] Cross-sectional view of body part and connecting part according to embodiments of this disclosure [Figure 9] Cross-sectional view of body parts and connecting parts when secondary resin flows in according to the embodiment of the present disclosure. [Figure 10] Top view of body parts and connecting parts when secondary resin flows in according to the embodiment of this disclosure [Figure 11] Cross-sectional view of body parts and connecting parts relating to a modified example of this disclosure [Figure 12]Perspective view of a modified example of a circulation unit according to an embodiment of the present disclosure

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] <Liquid ejection head> FIG. 1 is an exploded perspective view of a liquid ejection head 100. First, the schematic configuration of the liquid ejection head 100 of the present embodiment will be described with reference to FIG. 1.

[0012] The liquid ejection head 100 includes a circulation unit 1 that circulates ink inside, a main body connection member 2 that is connected to a liquid ejection device main body (not shown), and a flow path member 3 that houses the circulation unit 1. The liquid ejection head 100 also includes a support member 4 disposed on the lower surface of the flow path member 3, and a recording element substrate 5 that ejects liquid through the support member 4. Further, the liquid ejection head 100 includes a lower cover 6 that covers the lower surface of the recording element substrate 5, an electrical wiring substrate 7 that can be electrically connected to the recording element substrate 5, and an upper cover 8 that covers the upper surface of the circulation unit 1.

[0013] The circulation unit 1 includes four circulation units respectively corresponding to each of the inks of black (Bk), cyan (C), magenta (M), and yellow (Y). Each ink of the circulation unit 1 is supplied from a liquid ejection device main body (not shown) and is supplied to the recording element substrate 5 through the flow path member 3. Note that the number of colors, that is, the number of circulation units, can be determined as desired. Hereinafter, it will be simply referred to comprehensively as "circulation unit 1".

[0014] The circulation unit 1 includes a plurality of connecting parts 10 (see FIG. 2) described later and is connected to the main body connection member 2 and the flow path member 3 respectively. The circulation unit 1 can circulate the ink supplied from the liquid ejection device main body.

[0015] The main body connection member 2 is connected to the liquid discharge device main body on one side and to the circulation unit 1 on the other side. The main body connection member 2 is connected to the connection part 16 of the circulation unit 1 described later. Thereby, the main body connection member 2 can supply the ink supplied from the liquid discharge main body to the circulation unit 1.

[0016] The flow path member 3 houses the circulation unit 1 and is connected via the connection part 16 of the circulation unit 1. The flow path member 3 can supply the ink supplied from the circulation unit 1 to the recording element substrate 5.

[0017] The support member 4 is connected to the lower surface of the flow path member 3. The support member 4 is also connected to the recording element substrate 5. By being connected to the flow path member 3, the support member 4 can supply ink to the recording element substrate 5. The connection method between the support member 4 and the flow path member 3 may be adhesion using an adhesive or fixation by screwing. The support member 4 and the recording element substrate 5 are adhered by an adhesive.

[0018] The electrical wiring board 7 is fixed by adhesion to the surface of the flow path member 3 facing the main body connection member 2. The electrical wiring board 7 is electrically connected to the circulation unit 1 and the recording element substrate 5. By receiving an electrical signal from the liquid discharge device main body and transmitting the electrical signal to the circulation unit 1 and the recording element substrate 5, the recording element substrate 5 can discharge ink.

[0019] <Circulation Unit> Figure 2(a) is a diagram clearly showing the cylindrical portion of the circulation unit 1. Figure 2(b) is a cross-sectional view taken along line IIb-IIb in Figure 2(a). The circulation unit 1 is composed of a body part 9 and a plurality of connecting parts 10. The body part 9 has a cylindrical portion 20 that houses the ring-shaped connecting parts 10. The cylindrical portion 20 has a first support part 19 that supports the first molded product 13 from around its ring shape, and a second support part 21 that supports the first molded product 13 from the direction in which the liquid flows (downward in the figure). By inserting the main body connecting member 2 (see Figure 1) and the connecting member (not shown) of the flow path member 3 into the cylindrical portion 20, an ink supply channel is formed that connects the main body connecting member 2 and the flow path member 3. As will be described in detail later, in this embodiment, the thickness b of the first support part 19 in the direction perpendicular to the ink flow direction, i.e., the direction in which the primary molded product is supported, is made smaller than the thickness a of the second support part in the ink flow direction. In the connecting component 10, it is preferable to form it from a highly elastic material to prevent ink leakage. For example, the connecting component 10 may be formed from a material that can be injection molded and has elasticity, such as a thermoplastic elastomer. This makes it possible to reduce the number of fastening members such as screws when connecting the circulation unit 1 and the main body connecting member 2, and to miniaturize the liquid discharge head.

[0020] The cylindrical portion 20 may be configured, for example, by incorporating an O-ring as a connecting component 10 into the opening of the body component 9. However, in the case of a configuration in which an O-ring is incorporated into the body component 9, a device for incorporating the O-ring is required, and there is a risk of foreign matter contamination during the incorporating process and a decrease in sealing performance due to foreign matter. Therefore, in this disclosure, the above concerns are resolved by forming the body component 9 and the connecting component 10 by two-color molding.

[0021] <Connecting parts> Figure 3(a) is a schematic diagram of a connecting part in two-color molding. When molding the connecting part 10, as shown in Figure 3, resin is poured from the gate 11 of the mold to form a ring-shaped connecting part 10. At that time, the resin is filled in order from the inner circumference to the outer circumference of the ring shape.

[0022] Generally, slight filling defects called welds can occur in the last part filled with resin. If these welds occur on the inner circumference of the ring shape, there is a risk that a gap will be created when other components connect with the connecting part 16. In this case, the sealing performance of the connecting part 10 will be reduced, which can cause leakage. However, with the configuration of the present disclosure, as shown in Figure 3(b), the last part filled with resin is on the outer circumference of the ring shape, and the configuration makes it difficult for welds to occur on the inner circumference of the connecting part 10. In this way, the connecting part 10 of the present disclosure can maintain sealing performance and suppress concerns about leakage.

[0023] In the configuration of this disclosure, the connecting part 10 is located inside the body part 9 in the cylindrical portion 20. Therefore, it is desirable to mold the connecting part 10 by primary molding and the body part 9 by secondary molding. If the body part 9 is molded by primary molding and the connecting part 10 is molded by secondary molding, a gate must be provided inside the body part 9 to allow resin to flow in in order to mold the connecting part 10. In this case, the gate is provided on the inner circumference side of the ring shape that will become the connecting part 10, and the resin is filled in order from the outer circumference side to the inner circumference side of the ring shape. As a result, weld lines are generated on the inner circumference side of the connecting portion 16, the sealing performance is reduced, and ink leakage is more likely to occur.

[0024] In this disclosure, the connecting part 10 is made of a thermoplastic elastomer, and the body part 9 can be made of a wide variety of resin materials such as polypropylene. When primary molding is performed with a primary resin (thermoplastic elastomer) and then secondary molding is performed with a secondary resin (such as polypropylene), the secondary resin comes into contact with the primary molded product, the connecting part 10, and a strong bond is formed by thermal compatibility. The higher the melting temperature of the body part 9 is than the melting temperature of the resin material of the connecting part 10, the stronger the bond between the connecting part 10 and the body part 9 becomes. On the other hand, when the body part 9 is molded in primary molding and then the connecting part 10 is molded in secondary molding, the body part 9 has already cooled to some extent and has a smooth surface, so the bonding strength with the connecting part 10 will be weaker. Therefore, in this disclosure, the connecting part is molded in primary molding and the body part is molded in secondary molding, resulting in a two-color molded product.

[0025] <Manufacturing of two-color molding> Figure 4 is a cross-sectional view of the connecting part 10 during primary molding, and Figure 5 is a top view. The mold 12 has a gate 11 for the flow of primary resin and a ring-shaped mold for molding the connecting part 10, which is the first molded product 13. When the primary resin flows in from the gate 11, the primary resin fills the ring shape from the inner circumference to the outer circumference. As the primary resin fills, it fills the outer circumference of the ring shape. This allows the connecting part 10, which is the first molded product 13, to be molded. After molding the first molded product 13 in this way, secondary resin is flowed in to mold the secondary molded product that will become the body part 9.

[0026] Figures 6 and 7 show comparative examples of this embodiment in secondary molding. Figure 6 is a cross-sectional view of the second molded product 14, which becomes the body part 9, and the first molded product 13, which becomes the connecting part 10, when the secondary resin flows in, in the comparative example. Figure 7 is a top view of the second molded product 14, which becomes the body part 9, and the first molded product 13, which becomes the connecting part 10, when the secondary resin flows in, in the comparative example. Note that the gate for the secondary resin to flow in is omitted in the figures.

[0027] In the comparative example, Figures 4 and 5 show the state in which, after the primary resin flows in, the secondary resin flows in from left to right along the flow direction 15. In the comparative example, the secondary resin flows in along the flow direction 15 with approximately the same pressure to both the area where the primary molded product is located and the area where the primary molded product is not located. The outer circumferential surface of the first molded product 13 becomes the joint surface 18 with the second molded product 14. When the secondary resin flows into the mold 12, as shown in Figure 7, the secondary resin flows around the outer circumference of the joint surface 18 of the first molded product 13 while in contact with it, and fills the mold 12. At this time, since the flowing secondary resin is at a high temperature, when it comes into contact with the joint surface 18 of the first molded product 13, the area around the joint surface 18 partially remelts and deforms. Then, as the secondary resin solidifies over time, the remelted and deformed first molded product 13 and the secondary resin combine and are molded as one unit. The remelted first molded product 13 softens during the remelting process, so it cannot maintain a suitable ring shape. The shape of the softened first molded product 13 is affected by the flow direction 15. The softened first molded product 13 may not be able to maintain a suitable ring shape, resulting in the formation of a deformed first molded product 13, which may reduce the sealing performance.

[0028] Therefore, in this embodiment, the inflow of secondary resin into the side surface of the first molded product 13 is suppressed.

[0029] Figure 8 is a cross-sectional view showing the second molded product 14 and the first molded product 13 in the cylindrical portion 20 according to this embodiment. The first molded product 13 includes an undercut portion 16 and a joining surface 18. The undercut portion 16 is the entire curved shape of the first molded product 13, and the sealing function is achieved when the tip of the curved portion is compressed when the circulation unit 1 is connected to the main body connecting member 2 or the flow path member 3.

[0030] In the cylindrical portion 20, the inside of the undercut portion 16 connects to the functional portion 17, which is an opening formed in the first molded product 13, and becomes an ink flow path. The first support portion 19 is in contact with the joining surface 18 on the side of the first molded product 13 and supports the first molded product from around its ring shape. The second support portion 21 is in contact with the bottom surface of the first molded product 13 and supports the first molded product from a direction intersecting the direction in which the first support portion 19 supports it. In this embodiment, the thickness b of the first support portion 19 in the direction perpendicular to the ink flow direction, i.e., the direction in which the primary molded product is supported, is made smaller than the thickness a of the second support portion in the ink flow direction. It is even more preferable that the thickness b is 2 / 3 or less of the thickness a. Also, the diameter α of the first molded product 13 is greater than the length β of the first molded product 13 in the direction in which the hollow region of the ring extends. As a result, as will be described later, the flow velocity of the secondary resin when it flows into the side surface of the first molded product 13 can be reduced.

[0031] Figures 9 and 10 show the configuration during the secondary resin inflow after the primary resin inflow in this embodiment. In Figures 9 and 10, the secondary resin flows from left to right along the flow direction 15. In the comparative example described in Figures 6 and 7, the secondary resin flowed perpendicular to the joint surface 18 of the first molded product 13 and was affected by its pressure. However, in this embodiment, the flow of the secondary molded resin from left to right is limited to the region of the second support part 21, and in the first support part 19, it is formed by a flow parallel to the joint surface 18. Generally, injection molding has the property of filling from the thicker parts first, so the area around the joint surface 18 of the first molded product 13 becomes the end of the secondary resin flow. Thus, according to this embodiment, flow perpendicular to the joint surface 18 of the first molded product 13, as shown in the comparative example, is unlikely to occur. Therefore, the influence of the secondary resin flow on the remelted resin of the first molded product 13 can be suppressed, and deformation of the first molded product 13 can be suppressed. As a result, a connecting portion with suitable sealing properties can be formed.

[0032] Furthermore, the smaller the width b of the first support portion 19 that contacts the joint surface 18, the more the flow rate of the secondary resin can be reduced, as long as the function of supporting the first molded product 13 is not impaired.

[0033] <Variation> Figure 11 is a cross-sectional view of a modified example of the cylindrical portion 20 according to this embodiment. Figure 12 is a perspective view of the circulation unit 1 molded according to this modified example. Compared to Figure 8, the shape may also be such that a third support portion 22 is provided on the outer circumference of the first support portion 19 which is molten with the first molded product 13 via the joint surface 18. This makes it possible to further suppress the flow velocity of the flow generated when the secondary resin is introduced.

[0034] <Other Embodiments> The disclosure of this embodiment includes configurations represented by the following example of a two-color molded product.

[0035] <Configuration 1> A two-color molded product having a primary molded product and a secondary molded product, The primary molded product has a ring shape into which other components can be inserted. The secondary molded product has a cylindrical portion that supports the primary molded product, The cylindrical portion comprises a first support portion that supports the primary molded product from around its ring shape, and a second support portion that supports the first molded product from a direction intersecting the direction in which the first support portion supports it. A two-color molded product characterized in that the thickness of the first support portion in the direction supporting the primary molded product is smaller than the thickness of the second support portion in the direction supporting the primary molded product.

[0036] <Configuration 2> The two-color molded product according to configuration 1, wherein the thickness of the first support portion in the direction of supporting the primary molded product is 2 / 3 or less of the thickness of the second support portion in the direction of supporting the primary molded product.

[0037] <Structure 3> The ring shape of the primary molded product is a two-color molded product according to claim 1, wherein the entire curved shape of the ring is an undercut portion.

[0038] <Structure 4> The two-color molded product according to configuration 1, wherein the primary molded product and the secondary molded product are molded from different materials.

[0039] <Composition 5> The two-color molded product according to configuration 4, wherein the melting temperature of the material of the secondary molded product is equal to or greater than the melting temperature of the material of the primary molded product.

[0040] <Composition 6> The material of the primary molded product is a thermoplastic elastomer, as described in configuration 5 for the two-color molded product.

[0041] <Composition 7> The two-color molded product according to configuration 6, wherein the material of the secondary molded product is polypropylene.

[0042] <Structure 8> A two-color molded product according to any one of configurations 1 to 7, used in a circulation unit of a liquid discharge head.

[0043] <Composition 9> The two-color molded product according to configuration 8, wherein the cylindrical portion functions as a path for supplying liquid to the circulation unit, and the primary molded product has a sealing function to suppress liquid leakage.

[0044] <Composition 10> The two-color molded product according to any one of configurations 1 to 9, wherein the diameter of the ring shape of the primary molded product is greater than the length in the direction in which the hollow region of the first support portion extends.

[0045] <Composition 11> The two-color molded product is a two-color molded product according to any one of the configurations 1 to 10, having a plurality of primary molded products.

[0046] <Composition 12> A primary molding process involves pouring primary resin into a mold to form a primary molded product having a ring shape, A secondary molding step involves pouring a secondary resin different from the primary resin into the mold to form a secondary molded product having a cylindrical portion that is joined to the outer circumference of the ring shape of the primary molded product and supports the primary molded product. A method for manufacturing a two-color molded product, The cylindrical portion comprises a first support portion that supports the primary molded product from around its ring shape, and a second support portion that supports the first molded product from a direction intersecting the direction in which the first support portion supports it. A method for manufacturing a secondary molded product, characterized in that the thickness of the first support portion in the direction of supporting the primary molded product is smaller than the thickness of the second support portion in the direction of supporting the primary molded product. [Explanation of symbols]

[0047] 10 connecting parts 13 First molded product 14. Second molded product 16 Connecting part 17 Functional Section 18 Joint surface 19. First support 20 Cylinder part 21 Second support

Claims

1. A two-color molded product having a primary molded product and a secondary molded product, The primary molded product has a ring shape into which other components can be inserted. The secondary molded product has a cylindrical portion that supports the primary molded product, The cylindrical portion comprises a first support portion that supports the primary molded product from around its ring shape, and a second support portion that supports the first molded product from a direction intersecting the direction in which the first support portion supports it. A two-color molded product characterized in that the thickness of the first support portion in the direction of supporting the primary molded product is smaller than the thickness of the second support portion in the direction of supporting the primary molded product.

2. The two-color molded product according to claim 1, wherein the thickness of the first support portion in the direction of supporting the primary molded product is 2 / 3 or less of the thickness of the second support portion in the direction of supporting the primary molded product.

3. The ring shape of the primary molded product is a two-color molded product according to claim 1, wherein the entire curved shape of the ring is an undercut portion.

4. The two-color molded product according to claim 1, wherein the primary molded product and the secondary molded product are molded from different materials.

5. The two-color molded product according to claim 4, wherein the melting temperature of the material of the secondary molded product is equal to or greater than the melting temperature of the material of the primary molded product.

6. The two-color molded article according to claim 5, wherein the material of the primary molded article is a thermoplastic elastomer.

7. The two-color molded article according to claim 6, wherein the material of the secondary molded article is polypropylene.

8. A two-color molded product according to claim 1, used in a circulation unit of a liquid discharge head.

9. The two-color molded product according to claim 8, wherein the cylindrical portion functions as a path for supplying liquid to the circulation unit, and the primary molded product has a sealing function to suppress liquid leakage.

10. The two-color molded product according to claim 1, wherein the diameter of the ring shape of the primary molded product is greater than the length in the direction in which the hollow region of the first support portion extends.

11. The two-color molded product is the two-color molded product according to claim 1, wherein the two-color molded product comprises a plurality of the primary molded products.

12. A primary molding process involves pouring primary resin into a mold to form a primary molded product having a ring shape, A secondary molding step involves pouring a secondary resin different from the primary resin into the mold to form a secondary molded product having a cylindrical portion that is joined to the outer circumference of the ring shape of the primary molded product and supports the primary molded product. A method for manufacturing a two-color molded product, The cylindrical portion comprises a first support portion that supports the primary molded product from around its ring shape, and a second support portion that supports the first molded product from a direction intersecting the direction in which the first support portion supports it. A method for manufacturing a secondary molded product, characterized in that the thickness of the first support portion in the direction of supporting the primary molded product is smaller than the thickness of the second support portion in the direction of supporting the primary molded product.

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