JPH0519909Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a magnetic tape cassette, and more particularly to a magnetic tape cassette having a cassette body on which a protective film layer made of a polymeric material or the like is formed on the surface. It is something.

(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 method requires a process of injection molding the body and a process of pasting paper, etc. on the outer surface of the body or a printing process, so it is difficult to print a predetermined design on the outer surface of the body at the same time as injection molding. A method called transfer molding was devised to do this. This transfer molding will be briefly explained below with reference to FIG. 4. Injection molding is performed using two molds 1 and 2, and when both molds 1 and 2 are put together, the shape of the cassette half formed by the recesses 3 and 4 of both molds 1 and 2 is formed. This is done by injecting a molten material such as a plastic material into a corresponding space from a gate 1a through an injection hole 1b. When performing transfer molding, both molds 1 and 2 are
A transfer film 5 provided with an ink layer having a predetermined design is placed between the two molds 1 and 2 with the two molds 1 and 2 separated, and the two molds 1 and 2 are placed between the two molds 1 and 2 with the transfer film 5 in between.
Match 2. After that, a predetermined amount of molten material is injected from the gate 1a, and the transfer film 5 is transferred to the mold 2.
The space inside the mold formed by the recesses 3 and 4 is filled with the molten material by pressing it against the recess 4 of the mold. At this time, the transfer film 5 is made by laminating 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. Upon contact with the molten material, the adhesive layer 9 bonds the ink layer 8 to the injection material or the surface of the cassette, and the release layer 7 allows the base film 6 to be easily peeled off from the cassette surface. Therefore, after this,
When the material filled in the mold space cools and solidifies, the body is taken out and the base film 6 is peeled off, leaving the ink layer 8 on the transfer film 5 in a transferred state on the surface of the body.

In this way, when an ink layer is transferred to the surface of the cassette body, this ink layer is exposed to the outside on the cassette surface, and the film strength of the ink layer formed by this transfer molding is not very strong, so it may be The ink layer may be rubbed or peeled off.

Furthermore, as mentioned above, if the cassette body is made by injection molding of plastic material, etc., it is easy to manufacture and mass-produce. Therefore, there is a problem that the impact strength is relatively low, and the body is easily damaged if the magnetic tape cassette is accidentally dropped on the floor.

For this reason, the present applicant performed injection molding similar to the above transfer molding using a protective film from which the release layer 7 of the transfer film 5 used in the above transfer molding was removed, and applied this protective film to the surface of the cassette body. We proposed a cassette body that is integrally joined to form a protective film layer. In this way, since the ink layer is located on the inner surface of the protective film layer and covered by the base film forming the protective film layer, there will be no problem of the ink layer peeling off during use of the cassette. Furthermore, if this protective film layer covers the ridges of the cassette body, even if the injection molded material has low impact strength and is easily damaged, the protective film layer that covers it from the outside increases the impact strength. This also reduces the problem of damage to the cassette body.

(Problems to be Solved by the Invention) However, the base film used for this protective film layer is made of a polymeric material such as polyethylene, and there is a problem that this base film is easily charged. For this reason, during injection molding, the protective film that is sent in the form of a strip as shown in Figure 4 becomes electrically charged and is attracted to the mold 2 as shown by the broken line in the figure, and the discharge phenomenon occurs. This may cause problems such as making it difficult to accurately control the feeding of the protective film, or the charging of the protective film layer may cause dirt and dust to easily adhere to the surface of the cassette body.

(Means for solving the problem) For this reason, in the present invention, the protective film layer is made to be less likely to be charged,
The purpose is to prevent the above problems from occurring, and for this purpose the magnetic tape cassette of the present invention is constructed as follows.

The cassette body of this magnetic tape cassette is made by injection molding of plastic material, etc., and the surface of the cassette body has a protective film layer placed in the injection mold and integrally bonded at the same time as the injection molding. The outer surface of this protective film layer is provided with an antistatic layer that is previously formed before injection molding.

(Function) If the magnetic tape cassette with the above configuration is used,
The protective film layer on the surface of the cassette body is prevented from being charged by the action of the antistatic layer, and the problem of dirt and dust adhering to the surface of the cassette body is reduced. Furthermore, since this antistatic layer is provided on the surface of the protective film by coating or the like before injection molding, the protective film, which is sent in the form of a single band during injection molding, may be applied to the mold or surrounding areas. This eliminates the possibility of adsorption to the protective film, making it easier to control the feed of the protective film.

(Embodiments) Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a magnetic tape cassette according to the present invention. A pair of winding hubs 21, 2 rotatably built-in and held in 15b, 15b (the hub portions 15b, 15b of the lower half 15 are not shown)
1 and a magnetic tape 22 wound around this winding hub.
It consists of The upper half 11 and the lower half 15 are each injection molded separately.
As shown in FIG. 2, which shows a cross section along the arrow - in the figure, each half 11, 15 includes a base body 13, 17 made of an injection material such as plastic, and a protective film covering the surface of the base body 13, 17. It consists of layers 12 and 16. At this time, it is desirable that the protective film layers 12, 16 be formed to at least cover the ridges 11a, 15a of the respective halves 11, 15 from the viewpoint of strengthening the cassette body.

This protective film layer 12, 16 is
When injection molding 1 and 15, this protective film layer 1 is formed at the same time as this injection molding.
The formation of 2 and 16 will be explained. This cassette body is manufactured using the molds 1 and 2 shown in FIG. 4, and injection molding of the upper half 11 will be explained as an example. FIG. 4 shows a case where injection molding is performed with the transfer film 5 sandwiched between the molds 1 and 2, but in the case of this embodiment, the transfer film 5
A protective film layer 12 is sandwiched instead. As shown in FIG. 3, this protective film layer 12 includes an ink layer 12b which has a design representing the external appearance of a magnetic tape cassette, etc. on the inner surface side of the base film 12a (the side that contacts the base body 13), and an ink layer 12b that protects the base film 12a. An adhesive layer 12c for bonding the film layer 12 to the base body 13 is laminated in this order, and an antistatic layer 12d is provided on the outer surface of the base film 12a. Note that, as the material for this base film 12a, a polymeric material such as polyethylene, polyethylene terephthalate, polypropylene, triacetate cellulose, etc. is used. Further, as the material of the antistatic layer 12d, conductive powder such as graphite, carbon black, carbon black graft polymer, etc.;
Natural surfactants such as sabonin; nonionic surfactants such as alkylene oxaside, glycerin, glycidol, polyhydric alcohols, polyhydric alcohol esters, alkylphenol EO adducts; higher alkylamines, cyclic amines, hydantoin derivatives , amidoamine, ester amide, quaternary ammonium salts, pyridine and other heterocycles, phosphonium or sulfonium, etc.; cationic surfactants such as carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester group, phosphoric ester group, etc. Amino acids; amino sulfonic acids, sulfuric acid or phosphoric acid esters of amino alcohols, amphoteric surfactants such as alkyl betaine type, etc. are used. Although it is possible to apply an antistatic agent to the surface of the cassette body after injection molding, it is easier to manufacture if it is applied to the surface of a single film-like protective film layer 12 as in the present invention. ,preferable.

Such a protective film layer 12 is continuously formed in a band shape, and the protective film layer 12 is sent downward in the figure so that its inner surface faces the mold 1 having the gate 1a, and the ink layer 12a is position it in place. At this time, since the antistatic layer 12d is provided on the outer surface of the protective film layer 12, the protective film layer 12 is charged and adsorbed to the mold 2 and the surrounding parts, as shown by the broken line in FIG. This can be prevented and feed control can be performed accurately. Next, the protective film layer 12
is held between the two molds 1 and 2, and then the injected material is injected from the gate 1a through the injection hole 1b into the recess 3,
4 into the space formed by. In this way, the space formed by both the recesses 3 and 4 is filled with the injection material while the protective film layer 12 is pressed against the recess 4 of the mold 2. At this time, this injection material comes into contact with the adhesive 12c of the protective film layer 12, and the adhesive forms the antistatic layer 12d, which forms the protective film layer 12, and the base film 1.
2a and the ink layer 12b remain integrated,
The injection material is bonded to the surface of the base body 13 which has cooled and hardened.

When the cassette body is manufactured in this way, a protective film layer 1 is applied to the surface by injection molding.
Since the outer surface of the protective film layer 12 is provided with an antistatic layer 12d, it is possible to prevent the cassette half from being charged. There is also less dirt and dust adhering to the surface. Furthermore, if an ink layer representing the exterior design of the cassette is previously provided on the inner surface of the protective film layer 12, it becomes possible to simultaneously display the design on the surface of the cassette by injection molding. However, in this case, the base film 12a needs to be transparent or semi-transparent,
Furthermore, it goes without saying that this ink layer may or may not be provided.

Although this example describes the case where the protective film layer is bonded to the cassette body surface,
In the case where only the ink layer is transferred to the surface of the cassette body, an antistatic layer may be provided on the outer surface of the transfer film. In this way, the transfer film becomes electrically charged, as shown by the broken line in FIG. ,
It is possible to prevent the transfer film from adhering to the mold or surrounding areas, making it easier to control the transfer film.

(Effects of the invention) As explained above, according to the invention, the cassette body of a magnetic tape cassette is made by injection molding of a plastic material, etc., and the surface of the cassette body is coated with a protective film that is integrally bonded at the same time as the injection molding. layer is formed and an antistatic layer is provided on the surface of this protective film layer, so
It is easy to manufacture a cassette body having a protective film layer on the surface, and a magnetic tape cassette using this cassette body is less likely to be charged with electricity during use, and less dirt and dust are attached to the cassette surface.
Furthermore, when feeding a band-shaped protective film layer between molds during injection molding, the problem of the protective film layer becoming electrically charged and adhering to the mold and surrounding parts, making feeding control difficult, is eliminated.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a magnetic tape cassette according to the present invention, FIG. 2 is a sectional view of the magnetic tape cassette taken along the arrow - in FIG. FIG. 4 is a cross-sectional view of the protective film layer to be bonded and formed; FIG. 4 is a cross-sectional view showing an injection mold used for transfer molding of a conventional magnetic tape cassette half; FIG.
The figure is a sectional view showing the transfer film for transfer molding. 1, 2...Mold, 5...Transfer film, 11...
...Top half, 15...Bottom half, 11a, 15a
...Ridge, 12, 16...Protective film layer, 1
3,17...Base body.

Claims (1)

[Scope of Claim for Utility Model Registration] 1) A magnetic tape cassette consisting of a magnetic tape, a pair of winding hubs, and a cassette body rotatably holding the winding hub with the magnetic tape wound therein, A cassette body is made by injection molding of a plastic material or the like, and a protective film layer is formed on the surface of the cassette body, which is placed in an injection mold and integrally bonded at the same time as the injection molding, A magnetic tape cassette, wherein the protective film layer has an antistatic layer provided on its outer surface before the injection molding. 2) The magnetic tape according to claim 1, wherein the protective film layer has, on its inner surface, an ink layer representing the design of the outer surface of the cassette, which is provided before the injection molding. Cassette.