Method for manufacturing erasers and apparatus for manufacturing erasers

Abstract

To provide a method for manufacturing an eraser and an apparatus for manufacturing the eraser that are capable of inexpensively manufacturing the eraser having a smooth surface.SOLUTION: A method for manufacturing an eraser 1 according to the present invention comprises: an extruding and molding step S1 for extruding a molten material of the eraser 1 to mold it into a belt-like shape; and a film sticking step S2 for disposing and pressing a film 2 onto a surface 1a of the extruded belt-like eraser material 1A in the extruding and molding step S1 to transfer a surface shape of the film 2 to the surface 1A of the belt-like eraser material 1A, and sticking the film 2 to the surface 1A of the belt-like eraser material 1A.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for manufacturing erasers and an eraser manufacturing apparatus.

Background Art

[0002] In recent years, transparent erasers and erasers of various colors have become popular products. For these transparent erasers and erasers of various colors, if the surface is smooth, the transparency becomes higher, and the color development is better due to the gloss. Conventionally, an eraser with a smooth surface has been formed by using a press molding apparatus having a mold with a smooth press surface and pressing an eraser material with this smooth press surface (see Patent Document 1). However, the press molding apparatus is costly to manufacture the mold. Therefore, every time the eraser shape is changed, the manufacturing cost of a new mold is incurred, increasing the production cost. Also, if the press surface of the mold is scratched, the scratches are transferred to the surface of all erasers. Therefore, in this case too, the manufacturing cost of a new mold is incurred. On the other hand, manufacturing erasers by extrusion molding is also being done. When manufacturing erasers by extrusion molding, the manufacturing cost can be reduced, but streaks may be formed on the surface of the eraser when it is extruded, and it is difficult to make the surface smooth.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides a method for manufacturing erasers and an eraser manufacturing apparatus that can manufacture erasers having a smooth surface at a low cost.

Means for Solving the Problems

[0005] To solve the above problems, the present invention provides a method for manufacturing an eraser, comprising: an extrusion molding step of extruding molten eraser material into a strip shape; and a film application step of placing a film on at least one surface of the strip-shaped eraser material extruded in the extrusion molding step and pressing it to transfer the surface shape of the film to the surface of the strip-shaped eraser material, and attaching the film to the surface of the strip-shaped eraser material.

[0006] Preferably, the strip-shaped eraser material has a rectangular cross-section perpendicular to the extrusion direction, and the surface of the strip-shaped eraser material to which the film is attached includes two opposing surfaces of the cross-section.

[0007] In the film application step, it is preferable to apply the film to the surface by pressing the strip-shaped eraser material between two opposing pressure rollers, with the film sandwiched between the pressure rollers and the strip-shaped eraser material.

[0008] In the film application process, the surface temperature of the pressing roller is preferably 80°C or higher and 140°C or lower.

[0009] It is preferable to include a cooling step after the film application step in which the strip-shaped eraser material to which the film has been applied is cooled.

[0010] Furthermore, in order to solve the above problems, the present invention provides an eraser manufacturing apparatus that includes an extrusion molding apparatus for extruding molten eraser material into a strip shape, and a film application apparatus for transferring the surface shape of the film to the surface of the strip eraser material by placing a film on at least one surface of the strip eraser material extruded in the extrusion molding apparatus and pressing it, and for attaching the film to the surface of the strip eraser material. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for manufacturing erasers and an apparatus for manufacturing erasers that can produce erasers having a smooth surface at low cost. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows a method for manufacturing an eraser 1 according to an embodiment, and an eraser 1 manufactured by an eraser manufacturing apparatus 100. [Figure 2] This is a diagram illustrating the eraser manufacturing apparatus 100. [Figure 3] This is a flowchart showing the manufacturing method of eraser 1. [Modes for carrying out the invention]

[0013] The following describes a method for manufacturing an eraser 1 and an eraser manufacturing apparatus 100 according to an embodiment of the present invention. Figure 1 shows an eraser 1 manufactured by the method for manufacturing an eraser 1 and the eraser manufacturing apparatus 100 according to an embodiment.

[0014] (Eraser 1) Eraser 1 is generally rectangular in shape and transparent or translucent, although this is not an exhaustive description. Of the six surfaces of eraser 1, the two largest, opposing surfaces 1a are smoother than the other surfaces. A smooth surface means that its surface roughness is lower and its gloss is higher than the other surfaces. Specifically, a smooth surface is preferably one with an arithmetic mean roughness (Ra) of 0.2 (μm) or less. The arithmetic mean roughness (Ra) is the result of measuring surface roughness in accordance with JIS B0601:2013. For measuring surface roughness, a scanning white light interference microscope, model name NewView® 7300, manufactured by Zygo Corporation, can be used.

[0015] In this embodiment, the eraser 1 has all six surfaces exposed, but it is not limited to this configuration; the film 2 described later may be attached to two smooth surfaces 1a.

[0016] (Eraser Manufacturing Device 100) Figure 2 is a diagram for explaining the eraser manufacturing device 100. The eraser manufacturing device 100 includes an extrusion molding device 10 that extrudes a molten eraser material and forms it into a strip shape, a film sticking device 20 that sticks a film 2 onto the surface of the strip-shaped eraser material 1A extruded by the extrusion molding device 10, and a cooling device 30 that cools the strip-shaped eraser material 1B with the film 2 stuck thereto by the film sticking device 20.

[0017] (Extrusion Molding Device 10) The extrusion molding device 10 includes a material input hopper 11, a cylinder part 12 having a cylinder part 12A and a head part 12B, and a screw part 16 disposed inside the cylinder part 12A.

[0018] (Material Input Hopper 11) The material input hopper 11 has a material input port 11a and guides the material of the eraser 1 input from the material input port 11a to the inlet 12a of the cylinder part 12. The material of the eraser 1 is, for example, a material obtained by preliminarily kneading a plasticizer and other additives in a predetermined ratio with a vinyl chloride resin serving as a base material and forming it into pellets, but it is not limited thereto, and a conventionally known eraser material can be used.

[0019] (Cylinder Part 12) The cylinder part 12 has a cylinder part 12A and a head part 12B provided on the tip side of the cylinder part 12A. The cylinder part 12A has an inlet 12a to which the material input hopper 11 is attached on the base end side, and a screw part 16 is disposed inside. The cylinder part 12A can further be heated inside by a heating device (not shown), and heats and melts the pellet-shaped eraser material input from the material input hopper 11.

[0020] (Screw Part 16) The screw part 16 is disposed in the internal space of the cylinder part 12A and is rotationally driven by a drive part (not shown). The screw part 16 extrudes the material input into the cylinder part 12A and heated and melted while kneading it toward the tip side of the cylinder part 12A.

[0021] (Head portion 12B) The head portion 12B is attached to the tip side of the cylinder portion 12A. A molding hole 12b through which the material heated and melted and kneaded in the cylinder portion 12A is extruded is formed on the tip side of the head portion 12B. The molding hole 12b is a rectangular (rectangular in this embodiment) hole, and a strip-shaped rubber material 1A having a rectangular cross section perpendicular to the extrusion direction is extruded from the molding hole 12b.

[0022] (Film attaching device 20) The film attaching device 20 includes two pressing rollers 21 facing each other that sandwich the strip-shaped rubber material 1A therebetween, and two supply rollers 22 around which the film 2 to be attached to the strip-shaped rubber material 1A is wound. The width of the film 2 wound around each supply roller 22 is preferably not less than the width of the strip-shaped rubber material 1A, and in the embodiment, the width of the film 2 is substantially equal to the width of the strip-shaped rubber material 1A.

[0023] The distance between the film attaching device 20 and the extrusion molding device 10 is short, and the strip-shaped rubber material 1A extruded by the extrusion molding device 10 can be processed by the film attaching device 20 before its temperature drops.

[0024] In the film attaching device 20, the film 2 is fed out from the two supply rollers 22 respectively and is disposed on the outer sides of two opposing surfaces in the long side direction of the cross section perpendicular to the extrusion direction of the strip-shaped rubber material 1A. Those two surfaces are the two largest opposing surfaces 1a when manufactured as the rubber 1.

[0025] Thus, the film 2 is disposed on the two surface 1a sides of the strip-shaped rubber material 1A and passes between the two pressing rollers 21 together with the strip-shaped rubber material 1A. Then, the film 2 is pressed and attached to the two surfaces 1a of the strip-shaped rubber material 1A by the pressing rollers 21.

[0026] The film 2 is a heat-resistant film that can withstand the temperature of the eraser 1 immediately after it is extruded from the extrusion molding device 10, and at least the surface that is pressed against the two surfaces 1a of the strip-shaped eraser material 1A is smooth. For film 2, examples include polyimide film, PET film, PEEK film, etc., but are not limited to these. Film 2 may also be fluororesin film, silicone film, polystyrene film, polyolefin film, metal foil, etc.

[0027] Examples of polyimide films include Kapton (registered trademark) manufactured by Toray DuPont, Apical (registered trademark) manufactured by Kaneka, Upirex (registered trademark) manufactured by Ube Industries, and Xenomax (registered trademark) manufactured by Xenomax Japan. Examples of PET films include Lumirror (registered trademark) manufactured by Toray Industries, Diafoil (registered trademark) manufactured by Mitsubishi Chemical Industries, and Toyobo Ester Film (registered trademark) manufactured by Toyobo Industries. Examples of PEEK films include Kurabo's Expeak® (registered trademark).

[0028] (Cooling device 30) The cooling device 30 includes a water tank 31 containing cooling water, and a plurality of guide rollers 32 that guide the strip-shaped eraser material 1B, to which the film 2 has been attached in the film application device 20, into the water tank 31, through the water tank 31, and out of the water tank 31.

[0029] (Manufacturing method for eraser 1) Next, the manufacturing method of the eraser 1 according to the embodiment will be described. Figure 3 is a flowchart of the manufacturing method of the eraser 1. The manufacturing method of the eraser 1 comprises an extrusion molding step S1, a film application step S2, a cooling step S3, and a cutting step S4.

[0030] (Extrusion molding process S1) The inside of the cylinder section 12A of the extrusion molding apparatus 10 is heated to a predetermined temperature, and the screw section 16 inside the cylinder section 12A is rotated. In this state, pellet-shaped eraser material is fed into the material input hopper 11. The fed pellet-shaped eraser material falls naturally from the inlet 12a by its own weight and is supplied into the cylinder section 12A. Inside the cylinder section 12A, the pellet-shaped eraser material is heated and melted, and the molten eraser material is kneaded by the rotating screw section 16 and sent to the tip of the cylinder section 12A, where it is extruded in a strip shape with a rectangular cross-section from the molding hole 12b provided in the head section 12B to the outside of the cylindrical section 12.

[0031] In this embodiment, in order to enable the application of film 2 in the following film application step S2, it is preferable not to perform a release treatment during extrusion molding, or to use a film 2 with a moderately heavy peeling force in the following film application step. Specifically, it is preferable that the film 2 has a peeling force that does not peel off the eraser material during the cooling step described later, and can be easily peeled off by hand after the cooling step or after completion (before using the eraser).

[0032] The eraser material is formed into a strip as it passes through the molding hole 12b and extruded as a strip-shaped eraser material 1A. The temperature of the strip-shaped eraser material 1A immediately after being extruded from the extrusion molding device 10 is approximately 100°C to 130°C.

[0033] (Film application process S2) Preferably, the two pressing rollers 21 are heated by a heating device (not shown) to a surface temperature of 80°C to 140°C, more preferably 90°C to 130°C, and in an embodiment to 100°C. The two pressing rollers 21 press the two surfaces 1a of the strip-shaped eraser material 1A extruded in the extrusion molding process S1 in a direction that brings the two surfaces 1a closer together, and the strip-shaped eraser material 1A is held between the two pressing rollers 21. The two pressure rollers 21 are pressed against and driven by the strip-shaped eraser material 1A that is fed out from the extrusion molding device 10, and rotate in accordance with the speed of the strip-shaped eraser material 1A. The peripheral speed of the two pressure rollers 21 is approximately equal to the extrusion speed from the extrusion molding device 10, so that the strip-shaped eraser material 1A passes through the film application device 20 without sagging, still at a high temperature and in a flexible state after being extruded from the extrusion molding device 10.

[0034] The film 2 dispensed from one supply roller 22 is inserted between the pressing rollers 21 together with the strip-shaped eraser material 1A, with the film positioned on one surface 1a side of the strip-shaped eraser material 1A. The film 2 dispensed from the other supply roller 22 is inserted between the pressing rollers 21 together with the strip-shaped eraser material 1A, with the film positioned on the other surface 1a side of the strip-shaped eraser material 1A. Then, the strip-shaped eraser material 1A is pressed by the pressure roller 21 and fed while sandwiched between the two surfaces 1a, with the film 2 placed on top of each other.

[0035] Immediately after being extruded from the head section 12B of the extrusion molding apparatus 10, the strip-shaped eraser material 1A is at a high temperature and in a flexible state. Since the film application apparatus 20 is located adjacent to the head section 12B of the extrusion molding apparatus 10, the strip-shaped eraser material 1A remains at a high temperature and in a flexible state even as it passes through the pressure roller 21. Therefore, when the strip-shaped eraser material 1A is pressed by the pressure roller 21, the smooth surface shape of the film 2 is transferred to the two surfaces 1a, making the two surfaces 1a smooth. Then, with the film 2 attached to the surfaces 1a, the strip-shaped eraser material 1A is transported to the cooling device 30.

[0036] (Cooling process S3) The strip-shaped eraser material 1B with the film 2 attached is guided into the water tank 31 containing cooling water by the guide roller 32 of the cooling device 30. As the strip-shaped eraser material 1B with the film 2 attached is cooled in the water tank 31, the two surfaces 1a to which the film 2 is attached solidify into a smooth state.

[0037] Subsequently, the film 2 is peeled off the strip-shaped eraser material 1B to which it is attached, cut to a predetermined length, and the eraser 1 shown in Figure 1 is manufactured. Note that the film 2 may be peeled off after cutting, or it may be left attached for protection.

[0038] As described above, the method for manufacturing the eraser 1 according to the embodiment includes an extrusion molding step S1 in which the heated and melted eraser material 1 is extruded and formed into a strip shape, and a film application step S2 in which a film 2 with a smooth surface is placed on the two surfaces 1a of the strip-shaped eraser material 1A extruded in the extrusion molding step S1 and pressed while the strip-shaped eraser material 1A is still flexible, thereby attaching the film 2 to the surfaces 1a of the strip-shaped eraser material 1A.

[0039] Furthermore, the eraser manufacturing apparatus 100 according to the embodiment includes an extrusion molding apparatus 10 that extrudes the heated and melted eraser material 1 into a strip shape, and a film application apparatus 20 that places a film 2 with a smooth surface on the surface 1a of the strip-shaped eraser material 1A extruded from the extrusion molding apparatus 10 while the strip-shaped eraser material 1A is still flexible, and presses it to attach the film 2 to the surface 1a of the strip-shaped eraser material 1A.

[0040] As a result, according to this embodiment, the two surfaces 1a of the strip-shaped eraser material 1A extruded from the extrusion molding apparatus 10 can be pressed by the smooth surface film 2 while the strip-shaped eraser material 1A is still flexible. Therefore, the smooth surface of the film 2 is transferred to the surface 1a, and the surface 1a becomes smooth in the eraser 1 that has been cut to a predetermined length. When the surface 1a becomes smooth, the transparency increases in the case of a transparent eraser 1 as in this embodiment. Furthermore, the present invention is also applicable to erasers other than transparent ones, such as colored erasers, and in the case of colored erasers, the glossiness is improved, resulting in better color development and clearer colors.

[0041] Unlike the embodiment, it is also conceivable to smooth the surface of the pressing roller 21 without attaching the smooth film 2 and press it directly against the surface 1a of the strip-shaped eraser material 1A, or to press the smooth film 2 against the surface 1a of the strip-shaped eraser material 1A only when it is being pressed by the pressing roller 21. However, in this case, the time that the surface 1a of the strip-shaped eraser material 1A is in contact with the smooth surface will be short. Also, in the subsequent cooling step S3, since the film 2 is not attached to the surface 1a of the strip-shaped eraser material 1A, there is a possibility that the surface 1a will be scratched. Therefore, the smoothness of the surface 1a of the strip-shaped eraser material 1A will be lower compared to the embodiment.

[0042] However, according to the manufacturing method and eraser manufacturing apparatus 100 of the embodiment, the strip-shaped eraser material 1A is cooled while the film 2 is still attached, so the smooth surface of the film 2 can be sufficiently transferred to the surface 1a of the strip-shaped eraser material 1A. Furthermore, the surface 1a can be protected in the subsequent cooling step S3. Therefore, the smoothness of the surface 1a of the eraser 1 can be increased. Furthermore, since extrusion molding makes it possible to manufacture erasers with a smooth surface, manufacturing costs can be reduced.

[0043] Although preferred embodiments of the present invention have been described above, the invention is not limited thereto, and various modifications are possible. For example, in this embodiment, the film 2 was applied after extrusion molding and then cooled, but it is also possible to perform extrusion molding, cool the material, then reheat it, and then apply the film 2. Also, in this embodiment, the film 2 was applied to two surfaces 1a, but it is also possible to apply the film 2 to other surfaces. Furthermore, the film 2 may be applied to only one surface 1a. Furthermore, for example, in the embodiment, the two pressing rollers 21 were pressed against and driven by the strip-shaped eraser material 1A delivered from the extrusion molding apparatus 10, but one may rotate on its own and the other driven, or each may rotate on its own so that both peripheral speeds are the same. In the embodiment, the cooling process S3 was performed in a water tank 31, but it may also be performed with cold air, or after cutting to a predetermined length, cooling in the atmosphere with the film 2 still attached. [Explanation of symbols]

[0044] 1 Eraser 1A, 1B Strip-shaped eraser material 1a surface 2 films 10 Extrusion molding apparatus 20 Film application device 21 Pressure roller 22 supply rollers 30 Cooling device 100 Eraser Manufacturing Machine

Claims

1. An extrusion molding process in which molten eraser material is extruded and formed into a strip, A film application step is performed in which a film is placed on at least one surface of the strip-shaped eraser material extruded in the extrusion molding step and pressed to transfer the surface shape of the film to the surface of the strip-shaped eraser material, and the film is attached to the surface of the strip-shaped eraser material. After the film has been attached by the aforementioned film attachment process, a cutting process is performed to cut the strip-shaped eraser material to a predetermined length. A step of peeling the film off the eraser material to which the film is attached, including, The method for manufacturing erasers.

2. The strip-shaped eraser material has a rectangular cross-section perpendicular to the extrusion direction. The surface to which the film is attached in the strip-shaped eraser material includes two opposing surfaces of the cross-section, A method for manufacturing an eraser according to claim 1.

3. The aforementioned film application process is as follows: The strip-shaped eraser material is pressed between two opposing pressure rollers, with the film sandwiched between the pressure rollers and the strip-shaped eraser material, thereby attaching the film to the surface. A method for manufacturing an eraser according to claim 1 or claim 2.

4. In the film application process, the surface temperature of the pressing roller is 80°C or higher and 140°C or lower. The method for manufacturing an eraser according to claim 3.

5. The process includes a cooling step after the film application step, in which the strip-shaped eraser material to which the film has been applied is cooled. A method for manufacturing an eraser according to claim 1 or claim 2.

6. An extrusion molding apparatus that extrudes molten eraser material and forms it into a strip, A film application device that, by placing a film on at least one surface of the strip-shaped eraser material extruded in the extrusion molding apparatus and pressing it, transfers the surface shape of the film to the surface of the strip-shaped eraser material and adheres the film to the surface of the strip-shaped eraser material, The device includes a device for cutting the strip-shaped eraser material to a predetermined length after the film has been applied by the film application device. Eraser manufacturing machine.

Images