JPH0528630Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetic tape cassette, and more particularly to a magnetic tape cassette having a cassette body made by transfer molding.

(Prior Art) A magnetic tape cassette is constructed by holding a winding hub on which a magnetic tape is wound inside a cassette body. This cassette body is usually made by injection molding of plastic material, etc. After this molding, paper or the like with a predetermined design is pasted on the outer surface of the body for the purpose of obtaining a design effect. A predetermined design can be printed directly.

However, this requires a process of injection molding the body and a process of attaching paper or the like to the outer surface of the body or a printing process, so a method called transfer molding has been devised in which a predetermined design is printed on the outer surface of the body at the same time as injection molding. This transfer molding will be briefly explained below with reference to Fig. 6. Injection molding is performed using two dies 1 and 2, and is performed by injecting a molten material such as a plastic material through a gate 1a into a space corresponding to the shape of a cassette half formed by the recesses 3 and 4 of the dies 1 and 2 when the dies 1 and 2 are brought together. When transfer molding is performed, a transfer film 5 with an ink layer having a predetermined design is placed between the dies 1 and 2 with the dies 1 and 2 separated, and the dies 1 and 2 are brought together with the transfer film 5 sandwiched between them.
After this, a predetermined molten material is injected from the gate 1a, and the transfer film 5 is pressed against the recess 4 of the mold 2 to fill the mold space formed by the recesses 3 and 4. At this time, the transfer film 5 is made by laminating a transfer layer, for example, a release layer 7, an ink layer 8, and an adhesive layer 9 in this order on a base film 6, as shown in Fig. 7, and when the injected molten material comes into contact with the surface of the adhesive layer 9, the ink layer 8 is bonded to the injected material, i.e., the surface of the cassette, by the adhesive layer 9, and the base film 6 can be easily peeled off from the cassette surface by the release layer 7. Therefore, when the body formed by the material filling the mold space is taken out and the base film 6 is peeled off, the ink layer 8 on the transfer film 5 remains transferred to the surface of the body.

Conventionally, in order to prevent the ink layer 8 formed on the surface of the cassette body from peeling off, a protective film from which the release layer 7 of the transfer film 5 used for the transfer molding is removed is used to perform the same process as the transfer molding. A proposal has also been made for a cassette body in which a protective film layer is formed above the ink layer 8 by injection molding and integrally bonding the protective film itself to the surface of the cassette body.

(Problems to be solved by the invention) As described above, transfer molding using a transfer film has the advantage of simplifying the process of manufacturing the cassette body, but it also has the following problems. .

In other words, when molten resin is injected into the mold, the flow of the resin causes wrinkles in the transfer film, and these wrinkles can cause streak-like patterns or unevenness in the ink layer, and the design transfer Sometimes discrepancies occurred. One way to prevent wrinkles is to improve the fluidity of the resin and reduce the frictional resistance with the transfer film, for example by increasing the molding speed and resin temperature, but due to the high temperature of the injected resin, the following A problem like this was occurring.

Conventionally, in the case of a resin injection structure called a pin gate as shown in FIG. 6, for example, the resin injected from the gate 1a concentrates on approximately one point on the transfer film and flows out. That is, the resin fills the mold while making spot contact with the transfer film. For this reason, even though the mold is cooled, the high-temperature resin of, for example, around 250°C (approximately 300°C if there is a shear heat caused by the restriction of the injection hole) continuously comes into contact with the resin at the resin outlet. For example, there was a problem in which the ink layer melted (hereinafter referred to as "burning") at a heat-resistant temperature of about 200°C.

(Purpose of the invention) The present invention was made in view of the above-mentioned problems, and it is an object of the present invention to provide a magnetic tape cassette equipped with a cassette body that eliminates the problem of burning of the ink layer due to high-temperature resin. .

(Means for Solving the Problems) The object of the present invention is to provide a magnetic tape cassette having a cassette body consisting of upper and lower halves formed by transfer molding in which at least an ink layer of a transfer film is integrally bonded to the surface of the cassette body. This is achieved by a magnetic tape cassette characterized in that the ink layer with which the resin injected from the injection hole of the injection mold makes spot contact is formed in a non-designed part.

(Embodiments) Hereinafter, preferred embodiments of the present invention illustrated in the drawings will be described.

FIG. 1 is a perspective view showing a magnetic tape cassette according to the present invention. A hub 13 is rotatably built in. Then, the upper half 10 and the lower half 11
are injection molded separately,
As shown in FIG. 2, which shows a cross section along the arrow - in FIG.
Base bodies 10a and 11a made of plastic injection material such as ABS resin, and base body 1
It consists of a protective film layer 12 that covers the surfaces of 0a and 11a. In addition, at this time, the transfer film 2
It is preferable that the protective film layer 12 formed by the protective film layer 12 be formed to cover at least the ridges 10b, 11b of each half 10, 11 from the viewpoint of strengthening the cassette body.

This protective film layer 12 has each half 10, 11
The protective film layer 12 is formed simultaneously with the injection molding, and the formation of the protective film layer 12 will be described below. This cassette body is made using two appropriately divided molds as in the past, but as shown in FIG. 4, for example, four molds are simultaneously molded using one half of the mold. A protective film layer 12 is formed on the surface of the cassette body by sandwiching the transfer film 20 between the mold 1 and another mold (not shown) corresponding to the mold 1 and performing injection molding. The transfer film 20 is a belt-shaped film in which the protective film layer 12 is formed in a pattern corresponding to the mold, and is intermittently sent downward in the figure (in the direction of arrow B), for example.
Further, during injection molding, it is held by, for example, plate-shaped holding means 21 so that appropriate tension is generated in the direction of arrow A.

As shown in FIG. 3, this protective film layer 12 has an ink layer 12b on the inner surface of the base film 12a (the side in contact with the base bodies 10a, 11a), which has a design representing the external appearance of the magnetic tape cassette. An adhesive layer 12c for bonding the protective film layer 12 to the base bodies 10a, 11a is laminated in this order, and an antistatic layer 12d is provided on the outer surface of the base film 12a as necessary. be. In the ink layer 12b, a non-design portion 30 of an appropriate size is formed in a region where resin injected from a gate 1a, which will be described later, hits in spots. Further, as the material for the base film 12a, for example, polymeric materials such as polyethylene, polyethylene terephthalate, polypropylene, triacetate cellulose, etc. can be used. Moreover, the antistatic layer 12
As d, for example, the one disclosed in Japanese Utility Model Application Publication No. 63-24773 can be used.

In this embodiment, molds 1 and 2 equipped with a gate 1a, generally called a tunnel gate, as shown in FIG. 5 are used. In this case, the resin injected from the gate 1a is transferred to the transfer sheet 20.
After being reflected on the wall surface on the opposite side, it fills the mold while hitting the protective film layer 12 of the transfer sheet 20 in spots. However, the transfer film 2 where the resin comes into contact with the spot spot
The 0 part is the non-design part 3 as shown in Figure 3.
0, even if the ink layer 12b is burnt due to the heat of the resin, there will be no problem in the design of the cassette body.

As a result, it is possible to use a resin having good fluidity at a higher temperature than before without having to consider the problem of burning of the ink layer 12b, and it is also possible to improve the wrinkle prevention effect of the transfer film 20.

The above-mentioned non-design portion 30 is a portion where the ink layer 12b does not provide a design effect, and the structure thereof is such that, for example, the ink layer 12b is of the same color as the base bodies 10a and 11a, or is colorless. , or base body 1 due to ink burnt.
Those that are almost the same color as 0a and 11a, and even
This is a general term for those in which the ink layer 12 is not provided.

In the embodiment described above, four non-design parts 30 (two in one half) are formed near the front opening of the cassette, but in the present invention, the number and position of the non-design parts 30 are limited to those in the embodiment described above. Rather, it is changed as appropriate depending on the gate position.

(Effects of the invention) As described above, according to the invention, the transfer layer of the transfer film, especially the ink layer, which is in spot contact with the resin injected from the gate of the injection mold, is made into a non-design part. Even if the transfer layer is burnt by the heat of the resin, there is no problem with the design of the cassette body, and problems such as poor appearance due to the burn are eliminated. In addition, as a result, it is possible to inject resin with good fluidity at a higher temperature than before into the mold, so the frictional resistance against the transfer film when the resin flows can be reduced, reducing the occurrence of wrinkles on the transfer film. can be effectively prevented.

[Brief explanation of the drawing]

1 is a perspective view showing an embodiment of the magnetic tape cassette according to the present invention, FIG. 2 is a sectional view taken along the arrow - in FIG. 1, and FIG. 3 is a cassette of the magnetic tape cassette shown in FIG. 1. FIG. 4 is a plan view showing one embodiment of a mold for injection molding the upper half of the magnetic tape cassette shown in FIG. 1, and FIG. Enlarged sectional view of main parts of the mold in the embodiment, No. 6
This figure is a sectional view showing an injection mold used for transfer molding of a cassette half of a conventional magnetic tape cassette, and FIG. 7 is a sectional view showing a transfer film related to the transfer molding shown in FIG. 6. 1, 2... Mold, 1a... Gate, 3, 4...
Concave portion, 5, 20...Transfer film, 10...Upper half, 11...Lower half, 10a, 11a...Base body, 12a...Base film, 12b
...Ink layer, 12c...Adhesive layer, 12d...
Antistatic layer, 21... holding means, 30... non-design portion.

Claims (1)

[Scope of utility model registration request] In a magnetic tape cassette equipped with a cassette body consisting of upper and lower halves formed by transfer molding in which at least an ink layer of a transfer film is integrally bonded to the surface of the cassette body, the resin injected from the injection hole of the injection mold is spotted. A magnetic tape cassette, characterized in that the contacting ink layer is formed in a non-design area.