JPH0721951B2 - Tape cassette and sliding sheet manufacturing method therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is used for a tape cassette around which a digital audio tape (DAT), a magnetic tape, a thermal transfer tape for a computer printout, and the like are wound.

The present invention relates to a tape cassette provided with a sliding sheet that smoothens the rotation of a tape and prevents noise and irregular winding of the tape, and a method for manufacturing the same. In particular, it relates to a hub type tape cassette and a method for manufacturing the sliding sheet thereof.

〔Overview〕

INDUSTRIAL APPLICABILITY The present invention relates to a tape cassette equipped with a sliding sheet for smoothing the rotation of the tape and preventing noise and irregular winding of the tape, in which a carbon thin film is formed on the base film of the sliding sheet by sputtering or other vapor phase process. By forming the, the coefficient of friction against the tape is reduced, the chargeability is reduced,
It is intended to improve various characteristics such as running characteristics and reproduction characteristics.

[Conventional technology]

Printing devices and recording / reproducing devices that use tape cassettes are always required to be faster and smaller. Along with this, the tape main body is being made faster and more durable and thinner, and there is a demand for the tape to be more precise and to run stably, and various improvements have been made for that purpose. For example, regarding the factors that influence the tape running system, the shape of the guide pin in the cassette and the shape in the tape running direction has been devised, and the sliding contact part with the tape edge related to the present invention has also been devised considerably. Has been done.

There are tape cassettes with or without a flange on the tape winding core member. Since the tape with a flange exists in the reel, the tape itself does not come into direct contact with the cassette case (shell) and there is no hindrance to the running even if there is some winding disorder.

However, without flange (commonly called hub type)
The tape is apt to be wound disorderly, the edge side of the tape comes into contact with the cassette case to damage the tape, or the running torque is increased due to the disordered winding to cause various troubles. This occurs because the hub itself has no flange and the vertical movement of the tape cannot be regulated during winding. Therefore, a method of preventing winding disorder by interposing two sliding sheets called friction sheets in the cassette and sandwiching the tape in a sandwich shape from above and below is adopted.
Further, various embossed shapes have been devised in order to further improve the prevention of winding disorder. Thus, the sliding sheet has been widely used for the purpose of preventing the running torque from being increased by the tape edge surface directly touching the cassette case.

On the other hand, as a material for the sliding sheet, a conductive material such as carbon black or graphite powder, a solid lubricant such as molybdenum disulfide, or a material obtained by mixing or coating a base film with silicone, a fluororesin, or the like has been conventionally used. It was However, in the case of mixing, the effect of lubrication is not remarkable due to the presence of the binder, and in the case of coating, there is a problem in the sustainability of the effect. In addition, they are opaque in nature and the inconvenience that the amount of tape wound cannot be observed from the outside with a cassette equipped with them.

On the other hand, in recent years, the one in which the amount of tape wound in the cassette can be observed from the outside has become mainstream, and a product using a highly transparent sliding sheet has been developed because of its merits in use. As such highly transparent sheets, those coated with silicone resin or fluororesin and those with antistatic properties are used, but these have poorer conductivity than sheets containing conductive materials. There is a problem of noise due to charging and charging and smooth running of the tape.

In addition, there is a device for forming a lubricating film on a sheet by using a thin film forming method, but the lubricating property, antistatic property and adhesion strength are insufficient.

As described above, although various studies have been made on the sliding sheet for improving the tape running property of the hub type cassette, a film having lubricity, antistatic property, durability, transparency and the like has been found. Not because
The reality is that a tape cassette that satisfies various characteristics such as smooth running of tape, durability, and low noise has not yet been obtained.

[Problems to be solved by the invention]

As described above, the conventional tape cassette still has problems in improving the running property and durability of the tape and reducing the noise generation. Further, since the rotation speed of the digital audio tape (DAT) is not constant, winding disorder is likely to occur.

The present invention provides a tape cassette with excellent performance by incorporating a sliding sheet that satisfies the above-mentioned various characteristics. In other words, the friction coefficient for the tape is low, the charging property is low to prevent dust and dirt from adhering, and it has rigidity that does not cause plastic deformation even in a temperature environment of about 90 ° C, and it has an excellent visual appearance. An object of the present invention is to provide a tape cassette that can improve various characteristics such as running characteristics and reproducing characteristics by providing a sheet.

[Means for solving problems]

A first aspect of the present invention is a tape cassette including a sliding sheet that slidably contacts an edge of a tape wound in a cassette case, wherein at least a part of the sliding sheet has a structure in which a carbon thin film is formed on a base film. Is characterized by.

A second invention is a method of manufacturing a sliding sheet that slides in contact with an edge of a tape wound in a cassette case, in which a carbon thin film is formed on a base film by a physical thin film forming method in which a carbon material passes through a vapor phase process. It is characterized by doing.

The physical thin film forming method is a method by sputtering,
It is preferable to use a glassy carbon material for the target.

[Action]

By forming a carbon thin film targeting a carbon material by a physical thin film forming method in a sliding contact portion in contact with the tape of the sliding sheet, the appearance is improved, and the friction coefficient at the time of sliding contact with the tape is reduced, The electrification becomes small, and plastic deformation does not occur even in a temperature environment of about 90 ° C, improving various characteristics such as tape running characteristics and reproducing characteristics.

Here, the "physical thin film forming method" means a thin film forming method via a gas phase process, and includes a vacuum vapor deposition method, a sputtering method,
It utilizes a vapor deposition mechanism or a sputtering phenomenon such as an ion beam sputtering method and an ion plating method. Among these physical thin film forming methods, in the present invention, the sputtering method, the ion beam sputtering method, and the ion plating method using a carbon material as a target are particularly preferable from the viewpoint of the implantation energy and the thin film structure described later.

The "carbon material" used in the present invention includes glassy carbon in addition to general graphite materials such as pyrolytic graphite, high-density graphite, and isotropic graphite. Is not particularly limited. Among these carbon materials, glassy carbon is preferable in terms of forming a more durable film. Further, among the physical thin film forming methods, the thin film forming method by the sputtering method is preferable in order to provide a carbon film having higher amorphousness.

According to the research conducted by the present inventors, the structure of the carbon thin film formed by the sputtering method reflects the structure of the target material, and therefore, the thin film obtained when glassy carbon is used as the target is: It is substantially amorphous and homogeneous, and has excellent durability.

The glassy carbon used for such a purpose can be obtained by curing and firing a thermosetting resin such as a phenol resin, a furan resin or an epoxy resin.

Furthermore, when glassy carbon with very few surface pores is used as a target, the time required to reach the background pressure of 1 × 10 −7 Torr for sputtering can be shortened, and the impure gas before and after sputtering can be shortened. It is also preferable in that the generation of carbon powder can be suppressed. As the glassy carbon raw material, any thermosetting resin capable of solid-phase carbonization can be used.
The materials described in 59-169915, JP-A-60-171208, JP-A-60-171209, JP-A-60-171210, and JP-A-60-171211 are more desirable because they are practically nonporous.

Furthermore, if the present invention is applied to, for example, a base film having high transparency and the thickness of a thin film to be formed is controlled, the transparency of the sliding sheet itself can be secured. The cassette using such a sliding sheet has a great advantage that the amount of tape winding can be easily observed from the outside. For this purpose, the carbon thin film needs to have a thickness of 1500 Å or less.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples, but the following Examples are merely examples of the present invention, and do not limit the technical scope of the present invention.

FIG. 1 is a front view of a sliding sheet of a tape cassette of an embodiment of the present invention, FIG. 2 is an enlarged sectional view thereof, and FIG. 3 is an exploded perspective view of a tape cassette equipped with a sliding sheet of an embodiment of the present invention. The sliding sheet 1 of the present invention has a carbon thin film 3 formed on the surface of a sliding sheet body 2, and a tape cassette has two sliding sheets 1 in cassettes 4 and 5 on the edge side of a tape 6. The carbon thin film 3 is formed so as to be in contact with the carbon thin film 3.

(Example 1) Glassy carbon (Grahard, manufactured by Kao Corporation) having a thickness of 3 m
It was processed into a disk shape of m, metal bonding was applied to a backing plate for oxygen-free copper sputtering, and the target was attached to the cathode of the device. A transparent polyethylene terephthalate film having a thickness of 50 μm was mounted on the counter electrode as a substrate to be coated, and this substrate was previously subjected to sputter etching treatment under water cooling, and then a carbon thin film was formed by sputtering. Using NPF Anelva's SPF430H as a sputtering device, a background pressure was set to a vacuum of 10-7 Torr as in the case of normal sputtering, and then argon gas was introduced up to 5 × 10-3 Torr as a discharge gas and a high frequency power of 400 W was applied. RF sputtering was performed. Obtained film thickness 30
The 0, 400 and 500Å carbon coated sheets have a brown color and are glossier and more aesthetically pleasing than the substrate polyethylene terephthalate film.

In order to understand the performance of the sliding sheet thus obtained, the friction coefficient with respect to the magnetic tape stock was measured using a friction coefficient test jig of ASTM D-1894 and Tensilon. The relative speed to the tape was 200 mm / min. The sheet was punched out into the shape shown in Fig. 1, and was inserted so that the carbon layer sputtered on the tape side was in contact between the cassette tape and the inner wall of the cassette, the audio cassette was assembled, and constant speed running and high speed unwinding The state of winding disorder of the tape after repeating 20 times was visually determined. The results are shown in the table. The winding torque is JIS-S8604.
The results are shown below, which are measured according to the measuring method of "winding torque and durability of cassette tape".

(Example 2) As in Example 1, using a high-density graphite material as a target,
Similarly, carbon films of 300, 400 and 500Å were formed on the PET film. Various characteristics of this sliding sheet were measured in the same manner as in Example 1, and using this, an audio cassette was assembled in the same manner as in Example 1 and its running characteristics were measured.

(Example 3) Glass-like carbon and a high-density graphite material were vapor-deposited at 2 × 10 -5 Torr under water cooling of a substrate PET film using an arc discharge type experimental ion plating apparatus. Various characteristics of this sliding sheet were measured in the same manner as in Example 1, an audio cassette was assembled using the same in the same manner as in Example 1, and its running characteristics were measured. Various characteristics were measured in the same manner as in Example 1.

Comparative Example 1 The PET film of the substrate used in the examples and the cassette using the same were used as a comparative example of the sheet and the cassette.

Comparative Example 2 With respect to the sliding sheet of the graphite filler / Teflon type commercially available cassette, various characteristics were measured in the same manner as in Example 1, and an audio cassette was assembled in the same manner, and its running characteristics were measured. This sheet was opaque and did not show any particular advantage in appearance.

(Comparative Example 3) Various characteristics were measured in the same manner as in Example 1 with respect to a sliding sheet of a commercially available cassette in which a silicon-based lubricating oil was applied on a PET film. This sliding sheet was embossed in three radial directions with respect to the winding of the tape.

The tape cassette of the present invention shown in Example 1-3 reflects the excellent surface smoothness, antistatic property, and durability of the sliding sheet incorporated therein, and is extremely excellent in running property.
Moreover, there was no problem such as adhesion of dust to the tape.
In addition, when the base film is made of a highly transparent material such as PET as in Examples 2 and 3, the film is transparent even after the carbon thin film is formed, and the winding amount in the cassette case is observed through this. It was possible.

[Advantages of the Invention] As described above, according to the present invention, surface smoothness in sliding contact with a tape, excellent antistatic property, excellent durability, various characteristics such as running characteristics and reproduction characteristics of the tape are improved, Due to the transparency, the amount of tape wound in the cassette case can be observed, and the appearance can be improved.

[Brief description of drawings]

FIG. 1 is a front view of a sliding sheet of a tape cassette according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view of the sliding sheet of the tape cassette according to the embodiment of the present invention. FIG. 3 is an exploded perspective view of a tape cassette provided with a sliding sheet according to an embodiment of the present invention. 1 ... Sliding sheet, 2 ... Sliding sheet body, 3 ... Carbon thin film, 4, 5 ... Cassette, 6 ... Tape.

Claims (3)

[Claims] 1. A tape cassette provided with a sliding sheet slidingly contacting an edge of a tape wound in a cassette case, wherein at least a part of the sliding sheet has a structure in which a carbon thin film is formed on a base film. Characteristic tape cassette. 2. A method for manufacturing a sliding sheet which is in sliding contact with the edge of a tape wound in a cassette case, wherein a carbon thin film is formed on a base film by a physical thin film forming method in which a carbon material passes through a vapor phase process. A method for manufacturing a sliding sheet, comprising: 3. The method for producing a sliding sheet according to claim (2), wherein the physical thin film forming method is a method by sputtering, and a glassy carbon material is used as a target thereof.