JPH0520844A - Tape cassette - Google Patents

Abstract

(57) [Abstract] [Object] The present invention can suppress an increase in dropout in a tape cassette storing a tape capable of recording and reproducing information such as music and images, and further, the tape can be stably run. It is an object of the present invention to provide a tape cassette that can be produced and has a small fluctuation in reproduction output level and that has a low manufacturing cost. [Structure] A pair of main body cases 4 and 5, a slider 10 that opens and closes a case window, a tape guide 1 that slides on the back side of a magnetic tape 3, a hub 6 and a guide roller 7. The pair of left and right guide posts 12 are formed separately from each other, and at least the tape guide 1 and the guide posts 12 are formed of a liquid crystal polymer.
The surface roughness of at least the surface of the guide post 12 that slides on the magnetic tape 3 is in the range of 0.3S to 2S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette that accommodates a tape capable of recording and reproducing information such as music and images and has a slider that opens and closes a window of a main body case, and particularly suppresses an increase in dropout. The present invention relates to a tape cassette in which fluctuations in reproduction output level are reduced.

[0002]

2. Description of the Related Art In a tape cassette containing a magnetic tape (hereinafter abbreviated as "tape"), a lower case 4 has two guide rollers 7 as shown in FIG. A tape guide 1 having a pair of left and right guide portions 1a, 1b, 1c is provided between 7 and 7. Further, a pair of left and right guide pins 2 are provided between the hub 6 and the guide roller 7. Conventionally, the tape guide 1 and the guide pin 2 and the body case 4 are integrally molded, and the molding material is, for example, a thermoplastic resin such as ABS resin or polystyrene resin.

[0003]

In recent years, with high density recording of magnetic recording, tape dropout becomes a fatal defect. Therefore, in Japanese Patent Application No. 1-321715, the window of the main body case has a slider. A tape cassette that can be opened and closed at is proposed. As a result, it is possible to prevent dust from entering the main body case from the outside of the main body case, and it is possible to suppress an increase in dropout significantly as compared to the conventional tape cassette without a slider as shown in FIG. It has become possible.

However, in the tape cassette of Japanese Patent Application No. 1-321715, like the conventional tape cassette, the tape guide 1 and the guide pin 2 and the main body case 4 are integrally molded. As a material, for example, a thermoplastic resin such as an ABS resin or a polystyrene resin is used. When reproduction is performed with such a tape cassette, the back surface of the tape is removed at a total of 8 positions of the guide portions 1a, 1b, 1c in the tape guide 1 and the guide pin 2 between the hub 7 and the guide roller 7 when the tape 3 is running. There was a serious problem that shavings were generated from the sliding surface when the tape was sliding, and the dropout increased as the number of tape passes increased.

Further, since the frictional resistance on the sliding surface during tape running is large, the tape running speed fluctuates,
There is a fatal defect in product quality that this appears as a fluctuation in reproduction output level.

When the tape cassette is formed of a material having excellent slidability such as polyacetal, the problems of abrasion of the sliding surface and frictional resistance can be solved to some extent. However, since the molding shrinkage rate is large, it is difficult to maintain a predetermined dimensional accuracy in mass production when the tape guide or guide post is used. As a result, the perpendicularity and parallelism of the guide portions 1a, 1b and the like of the tape guide are deviated, the tape running becomes uneven, and the reproduction output level fluctuation becomes large.

The present invention solves the above-mentioned conventional problems, suppresses the increase of dropouts, allows the tape to run stably, has a small fluctuation in reproduction output level, and has improved dimensional accuracy and stabilization. It is to provide a tape cassette. Furthermore, it is to supply a tape cassette having a low product cost.

[0008]

To solve the above problems, a tape cassette according to the present invention comprises a main body case, a slider for opening and closing a case window, a tape guide sliding on the back side of a magnetic tape, and a hub. A pair of left and right guide posts arranged between the guide rollers are separate bodies, or only the tape guide and the guide post are integrally formed, and at least the tape guide and the guide post are formed of a liquid crystal polymer, The surface roughness of at least the surface of the tape guide and the guide post that slides on the magnetic tape is in the range of 0.3S to 2S.

[0009]

With the above structure, the sliding characteristics of the tape guide and the guide post are improved, so that the sliding surfaces of the tape guide and the guide post with respect to the back surface of the tape are much less likely to be worn when the tape is running. The increase in dropout can be suppressed. Furthermore, since the molding shrinkage rate is small, the dimensional accuracy of the tape guide and guide post is improved, and the sliding characteristics are also improved, so it is possible to run the tape stably and uniformly, so that fluctuations in playback output level can be prevented. It can be extremely small.

[0010]

Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in FIG. 1, the tape cassette according to the present invention has a structure in which a main body upper case 5, a main body lower case 4, a tape guide 1, a pair of left and right guide posts 12 and a slider 10 are separate bodies. . Further, it has a hub 6 and a guide roll 7 like the conventional tape cassette. The tape guide 1 has a guide portion 1
a, 1b, 1c with a shield 9 in the center.
And the pad 8 is inserted. The guide post 12 is a hollow cylinder, and is inserted into the shaft 11 provided in the lower case 4 of the main body,
Moreover, the lower case 4 of the main body and the upper case 5 of the main body are sandwiched and fixed. Further, as a detent for the guide post 12, a convex portion is provided on the guide post 12 and a concave portion is provided on the lower case side. The relationship between the convex portion and the concave portion may be the reverse of the above-described configuration.

In FIG. 1, the tape guide 1 and the guide post 12 are shown as separate bodies, but for example (FIG. 3).
As shown in, the tape guide 1 and the guide post 12 may be integrated. In this case, the shaft 11 of the lower body case 4 shown in FIG. 1 is not provided.

In the tape cassette constructed as described above, as described above, the guide portion 1a of the tape guide 1,
Since the dimensional accuracy of the 1b and 1c perpendicularity, parallelism, etc. during mass production is improved, the dropout does not increase with the increase in the number of tape passes, and the reproduction output level fluctuation is further reduced, the present inventors have made the tape. The materials of the guide 1 and the guide post 12 were thoroughly studied. As a result, they have found that the object of the present invention can be almost achieved by molding with a liquid crystal polymer. It has also been found that a liquid crystal polymer containing a whisker such as zinc oxide can achieve the object of the present invention. However, as a result of further detailed studies on tape cassettes using the above materials, it was found that it is impossible to completely solve the problems of increase in dropout and fluctuation of reproduction output level only by specifying the material. did. Therefore, the present inventors have made extensive studies on the surface roughness of the tape sliding surface of the tape guide 1 and the guide post 12. As a result, it has been found that the object of the present invention can be achieved if the surface roughness is in the range of 0.3 S or more and 2 S or less in addition to the specification of the material described above. If the surface roughness is larger than this range, the frictional resistance when the tape slides becomes large, and the running of the tape becomes unstable and the reproduction output level fluctuation becomes large. Furthermore, shavings are generated on the sliding surface with the tape, increasing dropout. It was also found that when the surface roughness is less than this range, the tape sticks to the sliding surface, friction resistance increases, and tape running becomes unstable, resulting in large fluctuations in the reproduction output level.

The body cases 4 and 5 are made of ABS resin,
The slider 10 is made of polystyrene or the like, and the slider 10 is made of stainless steel or polyacetal or polyethylene. The hub 6 and the guide roll 7 are formed of, for example, polyacetal or the like.

In the tape cassette according to the present invention having the above structure, the tape guide 1 and the guide post 12 are
The result of measuring the dropout of the tape cassette molded from the liquid crystal polymer is shown in (Table 1), and the result of measuring the level fluctuation is shown in (Table 2). The surface roughness of the sliding surface of at least the magnetic tape of the tape guide and the guide post is 0.8S.

The dropout is measured every 1, 50 and 100 times as the number of times of tape pass, and the dropout is 1 ms as a reproduction output.
ec, -6 dB or more was detected. The reproduction output fluctuation was measured by recording at a recording signal frequency of 48 KHz and a recording time of 1 minute at three points along the entire tape length, examining the envelope of the reproduced waveform, and measuring the difference between the maximum and the minimum.

As a comparative example, the tape guide 1 and the guide post 12 are made of the same resin as that of the body cases 4 and 5 made of AB.
The result of the same measurement as described above for the molded product of S resin is shown in (Table 1) and (Table 2).

[0017]

[Table 1]

[0018]

[Table 2]

As shown in (Table 1) and (Table 2), it is understood that the tape cassette according to the present invention has an excellent effect in suppressing the increase of dropout and reducing the fluctuation of the reproduction output level.

[0020]

As described above, according to the tape cassette of the present invention, the dimensional accuracy of the tape guide and the guide post can be improved, and the dropout does not increase with the increase in the number of times of tape pass, and the reproduction is performed. Output level fluctuations can also be made extremely small, and product quality can be significantly improved. Further, by separating the tape guide and the guide post from each other, the upper and lower cases of the main body can be molded with a resin such as ABS or PS, which is low in cost, so that the manufacturing cost of the product is significantly reduced without impairing the effects of the present invention. It has become possible.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a tape cassette according to an embodiment of the present invention.

FIG. 2 is a perspective view of a tape guide.

FIG. 3 is an exploded perspective view of a conventional tape cassette.

[Explanation of symbols]

1 Tape guide 2 guide pins 3 tapes 4 Lower body case 5 Upper case 6 hubs 7 Guide roller 8 pads 9 shield 10 slider 11 axes 12 Guide post

Claims (6)

[Claims] 1. A main body case, a slider that opens and closes a case window, a tape guide that slides on the back side of a magnetic tape, and a pair of left and right guide posts that are arranged between a hub and a guide roller are separated from each other. Body, or only the tape guide and the guide post are integrally formed, at least the tape guide and the guide post are formed of a liquid crystal polymer, and the surface of at least the surface of the tape guide and the guide post that slides with the magnetic tape The roughness is 0.
A tape cassette characterized by being in the range of 3S to 2S. 2. A pair of left and right guide posts arranged between the hub and the guide roller are hollow cylinders, and the hollow cylinders are inserted into a shaft provided on the body case side. The tape cassette according to claim 1. 3. The tape cassette according to claim 1, wherein the tape guide and the guide post are formed of a liquid crystal polymer containing whiskers. 4. The tape cassette according to claim 1, wherein the whiskers are zinc oxide whiskers. 5. The tape cassette according to claim 1, wherein the whiskers are potassium titanate whiskers. 6. The tape cassette according to claim 1, wherein the liquid crystal polymer is wholly aromatic polyester.