Liquid storage container and manufacturing method thereof

Abstract

To provide a liquid storage container in which a main body portion and a liquid pouring portion made of resins of different kinds are joined by welding with high leakage resistance even if the resins are a combination of incompatible resins.SOLUTION: The liquid storage container comprises a main body portion configured to store a liquid, a liquid pouring portion connected to the main body portion and for pouring the liquid stored in the main body portion to outside, and a joining member disposed between the main body portion and the liquid pouring portion, in which a material of the main body portion contains a first resin, a material of the liquid pouring portion contains a second resin made of a material different from the first resin, and the joining member is a polymer alloy in which the first resin and the second resin are mixed. The main body portion and the liquid pouring portion are welded together via the joining member.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a liquid storage container and a method for manufacturing the same.

Background Art

[0002] Some liquid tanks used in liquid ejection devices such as inkjet devices have an injection port for injecting liquid, and the liquid can be replenished from a separately prepared liquid replenishment container (liquid storage container) through the injection port.

[0003] The liquid storage container has a bottle-shaped main body portion and a liquid discharge portion for supplying liquid to the storage tank of the liquid ejection device. The main body portion and the liquid discharge portion are each made of resin and are integrated by being joined. In this case, it is desirable to use welding as the joining method in order to enhance the liquid leakage resistance of the stored liquid.

[0004] Also, when selecting the materials for the main body portion and the liquid discharge portion, generally, resistance to the stored liquid, evaporation suppression effect, strength in the shape after molding, etc. are considered. When a single material alone cannot satisfy a plurality of requirements, a liquid storage container combining members of different materials may be configured. Liquid storage containers in which members of different materials are joined by various methods are disclosed. Patent Document 1 discloses a liquid storage container in which layers of different materials are laminated and molded for the inner layer and the outer layer of the main body portion. Patent Document 2 discloses a container in which a piece formed of a first material is inserted during the molding of a second material and laminated and molded. Further, Patent Document 3 discloses a container welded by disposing a multilayer sheet composed of a plurality of materials that weld to the materials of the respective members between two members formed of incompatible materials.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the case of Patent Document 1, if layers of different materials are combined using incompatible materials, delamination may occur between the two components due to changes in the temperature environment or stress during welding of other parts, potentially causing the contained liquid to leak.

[0007] Similarly, in the case of Patent Document 2, incompatible material combinations may result in delamination between components.

[0008] Furthermore, in the case of Patent Document 3, although each component and the layer on the surface of the multilayer sheet are compatible, delamination may occur at the adhesive layer within the multilayer sheet. In addition, the adhesive component and the liquid content may come into contact at the edge of the multilayer sheet, and the adhesive may adversely affect the liquid contained within. [Means for solving the problem]

[0009] The present invention, which solves the above problems, is a liquid container comprising: a main body configured to contain a liquid; a liquid dispensing section connected to the main body for dispensing the liquid contained in the main body to the outside; and a joining member disposed between the main body and the liquid dispensing section, wherein the material of the main body includes a first resin, the material of the liquid dispensing section includes a second resin of a different material from the first resin, the joining member is a polymer alloy of the first resin and the second resin, and the main body and the liquid dispensing section are welded together via the joining member. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a liquid container and a method for manufacturing the same in which the main body and liquid dispensing part, which are made of different resin materials, are joined by welding with high leakage resistance, even if the combination of resins is incompatible, thereby expanding the range of material selection for the liquid container. [Brief explanation of the drawing]

[0011] [Figure 1] This is an external view of a liquid storage container. [Figure 2] This is a cross-sectional view of the liquid dispensing section and the joint between the main body and the liquid dispensing section. [Figure 3] This is a cross-sectional view showing the joint between the main body and the liquid dispensing section. [Figure 4] This is a cross-sectional view showing an example of the shape of a joining member placed at the joint. [Figure 5] This is a cross-sectional view showing an example of the shape of a joining member placed at the joint. [Figure 6] This figure shows an example of the shape of a joining member placed at the joint. [Figure 7] This figure shows an example of the shape of a joining member placed at the joint. [Figure 8] This is a cross-sectional view showing an example of the shape of a joining member placed at the joint. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. The following embodiments describe a liquid container used as an ink container for an inkjet device. However, the liquid container of the present invention is applicable to various liquids and is not limited to the embodiments and specific examples shown below.

[0013] Figure 1 is an external view of the liquid container. The liquid container 1 has a main body 11, a liquid dispensing section 21 connected to the main body 11, and a cap section 31 attached to the liquid dispensing section 21. The main body 11 contains liquids such as ink used in the liquid dispensing device. The liquid dispensing section 21 dispenses the liquid contained in the main body 11 to the outside. The cap section 31, when attached to the liquid dispensing section 21, seals the inside of the liquid container (specifically, the main body 11) from the outside air. Figure 2 is a cross-sectional view of the liquid dispensing section 21 and the joint between the main body 11 and the liquid dispensing section 21.

[0014] The materials of the main body 11 and the liquid dispensing section 21 are selected based on hardness, impact resistance, evaporation suppression effect, and contact with the liquid to be contained. In order to construct a liquid container with desired properties, different materials may be selected for the main body 11 and the liquid dispensing section 21. For example, since the main body 11 has a larger surface area and thinner wall thickness than the liquid dispensing section 21, it is desirable that the material used for the main body 11 has better impact resistance and evaporation suppression effect than the material used for the liquid dispensing section 21. Therefore, by selecting different types of resin for the main body 11 and the liquid dispensing section 21, a liquid container 1 suitable for liquid storage can be constructed. The main body 11 contains a first resin, and the liquid dispensing section 21 contains a second resin, and it is preferable that the proportion of the first resin in the main body 11 and the proportion of the second resin in the liquid dispensing section 21 are 80% or more.

[0015] In this embodiment, polyethylene is selected as the material for the main body 11 (first resin) with an emphasis on superior contact with the liquid contents and evaporation suppression effect, while polypropylene is selected as the material for the liquid dispensing part 21 (second resin) considering contact with the liquid contents and weldability. Furthermore, high-density polyethylene is more preferable as the type of polyethylene used for the main body 11 from the viewpoint of strength and heat resistance after molding. Note that the first and second resins should be selected in any type and combination that provides the performance required for a liquid container, and are not limited to a combination of polyethylene and polypropylene.

[0016] In an ink storage container, it is common for both the main body and the liquid discharge part to be made of polypropylene. However, by making the main body 11 of polyethylene as in this embodiment, excellent evaporation suppression effect and impact resistance can be obtained compared to the case of polypropylene. In this case, the wall thickness of the main body 11 can be reduced, and the material used is reduced, so cost reduction is also possible.

[0017] On the other hand, if the main body 11 is made of polyethylene and, from the perspective of compatibility, the liquid discharge part 21 is also made of polyethylene, the compatibility in the materials of the main body 11 and the liquid discharge part 21 can be obtained. However, since polyethylene has a low coefficient of friction, the difficulty of welding is high in welding methods that require frictional heat such as ultrasonic welding and spin welding. There were cases where reliable welding could not be achieved while maintaining the shape of each member and having high liquid leakage resistance. Therefore, it is preferable to select resins of different materials, such that the main body 11 is made of polyethylene and the liquid discharge part 21 is made of polypropylene, as in the configuration of this embodiment.

[0018] Figure 3 is a cross-sectional view showing the joint portion 12 between the main body 11 and the liquid discharge part 21. The main body 11 and the liquid discharge part 21 are joined by welding, which is a joining method with high liquid leakage resistance. However, since polyethylene and polypropylene, which are the constituent materials of the main body 11 and the liquid discharge part 21 in this embodiment, are incompatible, it is difficult to directly weld the main body 11 and the liquid discharge part 21.

[0019] Therefore, as shown in Figure 3(a), a joining member 13 is placed between the main body 11 and the liquid dispensing part 21 at the joint portion 12 between the main body 11 and the liquid dispensing part 21. The joining member 13 is a polymer alloy in which the resins of the main body 11 and the liquid dispensing part 21 are mixed, and in this embodiment, it is a polymer alloy of polyethylene and polypropylene. In addition to the resins of the main body 11 and the liquid dispensing part 21, the joining member 13 may also contain a compatibilizer or the like. The joining member 13, being a polymer alloy, has a phase separation structure in which a polyethylene phase and a polypropylene phase exist. The polyethylene phase is welded to the main body 11 and the polypropylene phase is welded to the liquid dispensing part 21, thereby achieving welding between the main body 11 and the liquid dispensing part 21 via the joining member 13.

[0020] As in this embodiment, the present invention makes it possible to provide a liquid container in which the main body and liquid dispensing section, which are made of different resin materials, are joined by welding, even if the resins are incompatible. This expands the range of material selection for the liquid container.

[0021] The mass ratio of polyethylene to polypropylene in the joining member 13 is preferably in the range of 1:9 to 3:7. In this case, the welding properties between the joining member 13 and the liquid dispensing part 21 can be improved.

[0022] Furthermore, it is preferable that the joining member 13 be integrally molded with the main body 11 by two-color molding. If the mass ratio of polyethylene in the joining member 13 is low, it is thought that the bond with the polyethylene main body 11 will be weak. However, when the main body 11 and the joining member 13 are integrally formed by two-color molding, a stronger bond can be obtained compared to welding methods that join already molded members, such as spin welding or ultrasonic welding, because the resin temperature during the molding of the joining member 13 is higher.

[0023] Furthermore, if the mass ratio of polyethylene in the joining member 13 is low, the bond between the joining member 13 and the main body 11 may be weaker than the bond between the joining member 13 and the liquid dispensing part 21. In this case, it is also effective to select a polymer alloy for the main body 11 that has a first resin as the main component and contains a second resin. Here, the mass ratio of polyethylene to polypropylene in the main body 11 is preferably in the range of 8:2 to 9:1. For example, the liquid dispensing part 21 is made of polypropylene, the main body 11 is made of a resin mixed with polyethylene and polypropylene in a mass ratio of 9:1, and the joining member 13 is made of a resin mixed with polyethylene and polypropylene in a mass ratio of 1:9. As a result, the main body 11 and the joining member 13 can be bonded with both polyethylene and polypropylene, strengthening the bond between the joining member 13 and the main body 11.

[0024] The joining member 13 and the liquid dispensing section 21 may be welded by known methods such as spin welding or ultrasonic welding. As described above, the liquid container of the present invention can be manufactured by integrally molding the main body 11 and the joining member 13 by two-color molding or by joining them by known welding methods, and by joining the joining member 13 and the liquid dispensing section 12 by known welding methods.

[0025] Next, the shape of the joining member 13 will be described. Figure 3(b) is a cross-sectional view corresponding to AA' in Figure 3(a). As shown in Figure 3(b), the shape of the joining member 13 is preferably annular, encircling the outer wall of the main body 11 at the joining portion 12. This provides a weld with high resistance to liquid leakage at the joining portion 12.

[0026] Figure 4 is a cross-sectional view showing an example of the shape of a joining member 13 placed in the joint portion 12. As shown in Figure 4, it is preferable that the contact area between the joining member 13 and the main body portion 11 is larger than the contact area between the joining member 13 and the liquid dispensing portion 21. This is because it makes it less likely for the joining member 13 to peel off from the main body portion 11 due to stress generated during welding of the joining member 13 and the liquid dispensing portion 21, and stress caused by changes in the temperature environment after welding.

[0027] To increase the contact area between the joining member 13 and the main body 11 compared to the contact area between the joining member 13 and the liquid dispensing part 21, an uneven surface 14 may be provided on the surface of the joining member 13 that contacts the main body 11. This is because the anchoring effect of the uneven surface increases the adhesion between the members at the joint 12, suppressing delamination due to environmental changes such as temperature and stresses applied during welding.

[0028] Various shapes can be used for the uneven surface 14. Figures 5, 6, and 7 show examples of the shapes of the joining member 13 that are placed in the joining portion 12. Figure 5 is a cross-sectional view of the joining portion 12. Figures 6(a) and 7 are side views of the state in which the joining member 13 is formed on the main body portion 11, and the dashed lines indicate the uneven surface 14 present on the inner circumference side of the joining member 13. Also, Figure 6(b) is a cross-sectional view of the joining member 13 corresponding to BB' in Figure 6(a). For example, the uneven surface 14 may be ring-shaped unevenness as shown in Figure 5, or vertical unevenness may be arranged on the inner circumference side of the joining member as shown in Figure 6.

[0029] When the main body 11 and the liquid dispensing section 21 are welded together by ultrasonic welding, it is preferable to arrange the uneven shape 14 in a ring shape, as shown in Figure 5. During ultrasonic welding, ultrasonic vibrations are applied to the joint 12 in the vertical direction, so the ring-shaped uneven shape 14 receives the stress generated during ultrasonic welding, resulting in a higher anchoring effect.

[0030] When the main body 11 and the liquid dispensing section 21 are welded by spin welding, it is preferable to arrange the vertically oriented uneven shape 14 as shown in Figure 6. In spin welding, the liquid dispensing section 21, which is assembled to a predetermined position on the main body 11, is welded by rotating it in the circumferential direction. At this time, stress is generated in the circumferential direction, but if the uneven shape 14 is a vertically oriented uneven shape as shown in Figure 6, it is perpendicular to the stress, so a higher anchoring effect can be obtained than when the uneven shape 14 is ring-shaped as shown in Figure 5. Also, as shown in Figure 7, the uneven shape 14 may be arranged diagonally, so that the uneven shape 14 can receive both the downward stress generated when the liquid dispensing section 21 is positioned at a predetermined height on the main body 11 and the horizontal stress generated during spin welding.

[0031] As shown in Figure 8, the main body portion 11 may have a through hole 15, and the joining member 13 may be structured to penetrate the through hole 15 and extend across both the inner and outer walls of the main body portion 11. Figure 8(a) is a cross-sectional view of the joint portion 12, Figure 8(b) is a side view of the main body portion 11 having the through hole 15, and Figure 8(c) is a cross-sectional view corresponding to CC' in Figure 8(a). In this case, the joining member 13 and the main body portion 11 can be joined more firmly. [Explanation of Symbols]

[0032] 1. Liquid container 11 Main body 12 Joint part 13 Joining members 14 Uneven shape 15 Through holes 21 Liquid spout 31 Cap section

Claims

1. a body configured to contain a liquid; a liquid outlet portion connected to the main body portion and configured to outlet the liquid contained in the main body portion to the outside; a joint member disposed between the main body portion and the liquid outlet portion, the material of the main body portion contains a first resin, and the material of the liquid outlet portion contains a second resin different from the first resin, The bonding member is a polymer alloy in which the first resin and the second resin are mixed, The liquid storage container according to claim 1, wherein the main body and the liquid outlet are welded to each other via the joining member.

2. the first resin is polyethylene; The liquid storage container according to claim 1 , wherein the second resin is polypropylene.

3. The liquid storage container according to claim 2 , wherein a mass ratio of polyethylene to polypropylene in the joining member is in the range of 1:9 to 3:

7.

4. The liquid storage container according to claim 2 , wherein the first resin is high-density polyethylene.

5. The liquid storage container according to claim 1 , wherein an area of ​​the joint member in contact with the main body portion is larger than an area of ​​the joint member in contact with the liquid outlet portion.

6. The liquid storage container according to claim 1 , wherein the joining member has an uneven shape on a surface that comes into contact with the main body portion.

7. The liquid storage container according to claim 1 , wherein the main body portion has a through hole, and the joining member is formed so as to pass through the through hole.

8. The liquid storage container according to claim 1 , wherein the joint member is present on both an inner wall and an outer wall of the main body at a joint portion between the main body and the liquid outlet portion.

9. The liquid storage container according to claim 3 , wherein the main body further comprises polypropylene, and the main body comprises a polymer alloy in which a mass ratio of polyethylene to polypropylene is in the range of 9:1 to 8:

2.

10. The liquid container according to claim 1 , wherein the liquid is ink.

11. A liquid storage container as described in claim 10, which is an ink bottle for supplying the stored liquid to a liquid ejection device.

12. a body configured to contain a liquid; a liquid outlet portion for outletting the liquid contained in the main body portion to the outside; A liquid storage container having a joint member disposed between the main body portion and the liquid outlet portion, the material of the main body is a first resin, and the material of the liquid outlet is a second resin different from the first resin, The joining member is a polymer alloy in which the first resin and the second resin are mixed, A method for manufacturing a liquid storage container, comprising a welding step of welding the main body portion and the liquid outlet portion via the joining member.

13. The method for manufacturing a liquid storage container according to claim 12 , wherein the welding step includes a step of integrally molding the main body portion and the joining member by two-color molding.

14. A method for manufacturing a liquid storage container as described in claim 12, wherein in the welding process, the liquid pouring portion is welded while being rotated.

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