JPH0660601A - Tape cassette - Google Patents

Abstract

(57) [Summary] [Construction] In a tape cassette in which a magnetic tape 6 having a metal magnetic thin film as a magnetic layer is wound around reel hubs 4 and 5 and housed in a cassette body 1, the diameter of the reel hub is 10 mm or less. And [Effect] The area of shape transfer due to the deformation in the tape clamp portion can be minimized, and the magnetic tape can be effectively used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette containing a metal thin film type magnetic tape.

[0002]

2. Description of the Related Art In video tape recorders, audio tape recorders, and the like, tape cassettes in which a magnetic tape is wound and housed in a cassette body made of synthetic resin are widely used.

Heretofore, as a magnetic tape used in a tape cassette, a magnetic layer is formed by kneading magnetic powder with a resin binder to form a magnetic paint, and applying the magnetic paint on a base film. The so-called coating type magnetic tape is mainly used.

On the other hand, a magnetic tape (metal thin film type magnetic tape; so-called vapor deposition tape) having a metal magnetic thin film as a magnetic layer is being put to practical use for the purpose of supporting higher density recording. Incorporation of such a metal thin film type magnetic tape into a tape cassette is under consideration.

[0005]

By the way, the magnetic tape generally stored in the tape cassette is stored in a state of being wound around a reel hub. Therefore, the leading end and the end of the magnetic tape are clamped to the reel hub. It is in a state. Further, the winding state of the magnetic tape is irregular in this clamp portion, and this tends to deform the magnetic tape wound around this portion.

Deformation of the magnetic tape causes almost no problem in the coating type magnetic tape, but is greatly affected in the metal thin film type magnetic tape. For example, since the magnetic layer is a metal film, the magnetic tape is deformed by shape transfer. Deformation becomes remarkable, and the reproduction waveform is deteriorated due to a bad contact with the magnetic head.

Particularly, in a very thin metal thin film type magnetic tape having a thickness of about 10 μm or less, the shape-transferred area is almost unusable. This is extremely disadvantageous in promoting long-term recording of the tape cassette and improvement of manufacturing yield.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and aims to reduce the shape transfer area of the magnetic tape, and it is possible to secure a recording time and also in terms of manufacturing yield. An object is to provide an advantageous tape cassette.

[0009]

In order to achieve the above object, the tape cassette of the present invention comprises a magnetic tape having a magnetic layer of a metal magnetic thin film wound around a reel hub and housed in a cassette body. Diameter of the reel hub is 10m
It is characterized by being m or less.

[0010]

When the magnetic tape having the magnetic metal thin film as the magnetic layer is wound around the reel hub, the clamp portion of the magnetic tape is deformed by the shape transfer. The length L of the region where the shape transfer occurs is expressed by the following formula, where R is the diameter of the reel hub, where L = n (πR) [where n is the number of windings where the shape transfer occurs].

Therefore, by reducing the diameter R of the reel hub, the length L of the region where shape transfer occurs can be suppressed,
In particular, by setting the diameter R of the reel hub to 10 mm or less as in the present invention, the length of the unusable region due to a hitting failure or the like falls within a practically permissible range.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tape cassette to which the present invention is applied will be described below with reference to the drawings and experimental results. As shown in FIGS. 1 and 2, the tape cassette of the present embodiment is a metal thin film type magnetic tape wound around a pair of reel hubs 4 and 5 in a cassette body 1 composed of an upper half 2 and a lower half 3. 6 is stored.

The magnetic tape 6 is a so-called vapor deposition tape, and is made of a ferromagnetic metal material such as Co, Co-Ni, Co.
The magnetic layer is formed by vapor-depositing —Fe—Ni or the like directly on the base film.

The pair of reel hubs 4 and 5 are rotatably supported by the upper half 2 and the lower half 3, and the magnetic tape 6 is attached to the upper half 2 and the lower half 3.
Arc-shaped rising wall 3 according to the outer shape of the wound body
a and 3b are provided. Therefore, the magnetic tape 6 wound around the reel hubs 4 and 5 is rotatably and stably stored in the space surrounded by the rising walls 3a and 3b.

The reel hubs 4 and 5 are composed of inner hubs 4a and 5a and outer hubs 4b and 5b, respectively.
It is a so-called dual structure hub.

Both ends of the magnetic tape 6 are clamped by the clamp portions 41 and 51 provided on the reel hubs 4 and 5, respectively. The clamp part 41
[The same applies to the clamp portion 51. 3A and 3B, the reel hub 4 is provided in a divided form, and is integrally formed with the reel hub main body 42 such that one end 41a of the reel hub 4 is connected. It is a thing.

The reel hub main body 42 is provided with a recess 43 having a substantially circular cross section so that the inlet is narrow and the back is wide, and the clamp part 41 is provided with a substantially columnar projection 44 fitted in the recess 43. Has been.

Therefore, as shown in FIG. 3A, after inserting the magnetic tape 6 between the clamp portion 41 and the reel hub main body 42 with the clamp portion 41 opened, as shown in FIG. 3B. By pressing the convex portion 44 of the clamp portion 41 into the concave portion 43 of the reel hub main body 42, the outer peripheral surface 44 a of the convex portion 44 and the inner peripheral surface 4 of the concave portion 43 are pressed.
The tape end of the magnetic tape 6 is fixedly attached to the tape 3a.

Here, the convex portion 44 and the concave portion 43, for example, by making the outer diameter of the convex portion 44 slightly larger than the inner diameter of the concave portion 43, the binding force is considerably strengthened, and the tape end is strongly attached. I'm trying to fix it. This is an accident where the tape end is inadvertently pulled out from the reel hub when a large amount of tension is applied to the tape at the tape end during high speed running such as fast-forwarding and rewinding when the tape end has insufficient clinging force. This is to prevent However,
If the coupling force between the convex portion 44 and the concave portion 43 is increased in this way,
The magnetic tape 6 may be cut by the shearing force during press fitting.

Therefore, in the tape cassette of this embodiment,
A notch 45 is provided in the vicinity of the recess 43 provided in the reel hub body 42, one end of the recess 43 on the open end side serves as an elastic protrusion 46, and an inner peripheral surface 43a of the recess 43 is formed. Partly elastically displaceable.

Therefore, when the clamp portion 41 is press-fitted, the overhanging portion 46 in the vicinity of the concave portion 43 is pushed by the outer peripheral surface 44a of the convex portion 44 and bends, so that the shearing force acting on the tape end is greatly relaxed. Further, when the convex portion 44 completely enters the concave portion 43, the projecting portion 46 returns to its original state due to its elastic force, and the influence of the elastic deformation of the projecting portion 46 is:
It does not appear at all on the outer peripheral shape of the reel hub 4.

The notches 45 may be formed at positions near both sides of the recess 43 provided in the reel hub main body 42 as shown in FIG. 4, or as shown in FIG. You may form in the substantially central position of the convex part 44 provided in. In the latter case, the locking pieces 44b and 44c divided by the notches 45 play the role of the projecting portion 46, and at the time of press fitting, the locking pieces 44b and 44c are elastically displaced to reduce the resistance.

Alternatively, the clamp portion 41 may be formed separately from the reel hub body 42. Figure 6
6A and 6B, the clamp portion 41 is completely separated from the reel hub body 42, and the convex portion 44 provided on the clamp portion 41 is press-fitted into the concave portion 43 provided on the reel hub body 42 during clamping. It shows an example of being integrated only by.

To attach the magnetic tape 6 as shown in FIG.
After removing the clamp portion 41 and inserting the tape end as shown in FIG.
Press into.

Also in this case, the notches 45 are formed at positions near both sides of the recess 43, and the vicinity of the recess 43 is extended.
6, or the engaging piece 44 divided by forming a notch 45 at a substantially central position of the convex portion 44 provided on the clamp portion 41.
By setting b and 44c, the resistance at the time of press-fitting is remarkably alleviated as in the previous examples.

On the other hand, the cassette body 1 is provided with guide rolls 7 and 8 and guide pins 9 and 10, and the magnetic tape 6 is guided by these guide rolls 7 and 8 and guide pins 9 and 10. It is exposed to the outside of the cassette body 1 on the front surface of the cassette body 1 and comes into contact with a magnetic head of a recording / reproducing apparatus (not shown) when recording or reproducing.

A lid 11 also made of synthetic resin is rotatably attached to the front surface of the cassette body 1 by locking the rotating shaft 11a to the upper half 2, and when not in use, the cassette body 1 is provided. The magnetic tape 6 exposed to the outside of 1 is protected so that it is not inadvertently touched by fingers and the like.

The tape cassette of this embodiment is compatible with a recording / reproducing system using a rotary magnetic head mounted on a rotary drum. The front side of the cassette body 1 has an arc shape corresponding to the outer shape of the drum. The guide members 12 and 13 having the facing surfaces are attached. And, in the space formed by these guide members 12 and 13,
A rotary drum is inserted so as to press the magnetic tape 6 at the time of recording / reproducing, and a signal is recorded or reproduced on the magnetic tape 6.

In the tape cassette of this embodiment, the magnetic tape 6 to be housed has a tape width of 25 mm and a thickness of about 10 μm or less, and is very compact.

In the tape cassette having the above structure, the thickness of the magnetic tape 6 was set to 5 μm, and the allowable range of shape transfer depending on the reel hub diameter was examined. Shape transfer tolerance is 3
A signal with a constant level of MHz was recorded, the maximum output in the hit waveform was A, and the minimum output was B, and the distance from the reel hub clamp portion until 20 lgB / A was within 1 dB. The results are shown in Fig. 8.

As shown in FIG. 8, the distance in the shape transfer allowable range is reduced in proportion to the reel hub diameter. By setting the reel hub diameter to be 10 mm or less, the distance is 20 cm.
It can be seen that it can be suppressed to the following. Of course, this value may vary slightly depending on the thickness and material of the magnetic tape 6, but even if the magnetic tape has a thickness of 10 μm or less, if the reel hub diameter is 10 mm or less, the last part of the magnetic tape 6 will be used. It is considered that the margin of (this part is affected by storage etc.) can be estimated to be small and the yield can be improved.

[0032]

As is clear from the above description, in the present invention, the diameter of the reel hub around which the metal thin film type magnetic tape is wound is set to 10 mm or less, which results from the deformation in the tape clamp portion. The shape transfer area can be minimized, the magnetic tape can be effectively used, and the yield can be improved.

Also, when viewed from a tape cassette, the recording time can be extended, which is advantageous for downsizing.

Further, since the magnetic tape to be housed is a metal thin film type magnetic tape, it can be used for high-density recording and high-quality recording, and can therefore be compact and record for a long time.
Moreover, it is possible to provide a high performance tape cassette.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a configuration example of a tape cassette to which the present invention is applied.

FIG. 2 is a schematic plan view with an upper half removed.

FIG. 3 shows an example of a clamp portion of a reel hub,
FIG. 6A is a schematic plan view showing a state in which the clamp portion is opened, and FIG. 6B is a schematic plan view showing a state in which the clamp portion is press-fitted into the recess.

FIG. 4 is a schematic plan view showing another example of the clamp portion of the reel hub.

FIG. 5 is a schematic plan view showing still another example of the clamp portion of the reel hub.

FIG. 6 is a schematic plan view showing an example of a clamp portion formed separately from the reel hub body, in which (a) is a state in which the clamp portion is separated from the reel hub body;
FIG. 4 is a schematic plan view showing a state in which the clamp part is press-fitted into a recess of the reel hub body.

FIG. 7 is a schematic plan view showing another example of the clamp portion formed separately from the reel hub body.

FIG. 8 is a characteristic diagram showing a shape transfer allowable range depending on a reel hub diameter.

[Explanation of symbols]

 1 ... Cassette body 4, 5 ... Reel hub 6 ... Magnetic tape

Claims (1)

[Claims] 1. A tape cassette in which a magnetic tape having a metal magnetic thin film as a magnetic layer is wound around a reel hub and accommodated in a cassette body, and the reel hub has a diameter of 10 mm or less.