JPH05258506A - Magnetic tape cassette - Google Patents

Abstract

PURPOSE:To improve traveling stability of a magnetic tape at the time of recurrent traveling, to prevent corrosion caused from the edge face of magnetic tape at the same time, to improve reliability of long term preservation and to provide a compact magnetic tape cassette having superior performance, by incorporating a non-ionic surfactant in sliding sheets. CONSTITUTION:In the tape cassette constitute in such a manner that the sliding sheets 7 are arranged on each internal surface of upper/lower cassette halves 1 and made so as to slide in contact with the edge face of magnetic tape 3 wound around a pair of left/right reel hubs 2, the non-ionic surfactant is incorporated in the sliding sheets 7. Thus, a traveling property of magnetic tape is improved, and a deterioration from the edge face of magnetic tape is prevented, and dropout and clogging are also suppressed by increasing a corrosion resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cassette used for housing a metal thin film vapor deposition type magnetic tape suitable for high density porcelain recording.

[0002]

2. Description of the Related Art In the field of porcelain recording, high performance such as digitalization, miniaturization and long time has been advanced in recent years, and along with this, a ferromagnetic metal thin film which is advantageous for short wavelength recording and which can be thinned has been developed. Magnetic tapes used as magnetic layers are being actively studied. Development of video decks with high image quality, high performance, and ultra-miniaturization is underway. At the same time, in order to support such a deck, it is necessary to make the magnetic tape cassette even more compact, and as one of the means, a cassette without the upper and lower flanges in the reel hub around which the magnetic tape is wound is popular for implementation. Is being considered.

[0003]

However, in the magnetic tape cassette in which the flangeless reel hub is arranged as described above, the reel hub vibrates up and down when the magnetic tape is running, which makes it very unstable. Therefore, in order to ensure running stability, a means is provided in which the slippery sheet is arranged so as to be in sliding contact with both end surfaces of the magnetic tape wound around the pair of left and right reel hubs. Furthermore, in order to prevent running defects due to electrification during running of the magnetic tape, the running stability of the magnetic tape may be improved by applying an antistatic agent to the surface of the slip sheet or impregnating the slip sheet. I am trying. However, the antistatic agent is unstable and is exposed to an environment such as high temperature and high humidity, and is removed due to friction with the magnetic tape, etc., which deteriorates the running stability of the magnetic tape, and is further removed by running. An antistatic agent is attached to both end surfaces of a magnetic tape that makes sliding contact with a slippery sheet, and a magnetic tape having a ferromagnetic metal thin film as a magnetic layer is different from a so-called coating type magnetic tape in which magnetic particles are dispersed in a binder resin. Corrosion of the magnetic layer occurs from both end surfaces that are in sliding contact with the conductive sheet, and during recording / reproduction, corrosion products adhere to the head surface, which causes deterioration of image quality and noise due to reduction of reproduction output, or increase of dropout, and further magnetic There are problems such as fatal defects such as peeling of layers, and improvement in long-term storage reliability is desired. Various proposals have been made as measures for improving the above problems. For example, a protective film such as an anticorrosive agent may be formed on the magnetic layer (JP-A-58).
No. 189833), a back coat layer provided on the back side contains an anticorrosive agent (Japanese Patent Laid-Open No. 58-122621).
There is such a method. However, these methods have a problem that they do not show sufficient running stability and storage reliability, and only short-term running stability and storage reliability can be obtained, especially in a high temperature and high humidity environment.

The present invention is intended to solve the above-mentioned problems, in which the antistatic effect of the slippery sheet is prolonged, the running stability of the magnetic tape is improved, and the corrosion of the magnetic tape using the ferromagnetic metal thin film as the magnetic layer is achieved. In particular, the present invention provides a compact magnetic tape cassette that prevents corrosion from both end surfaces, improves long-term storage reliability.

[0005]

In order to solve the above problems, in the magnetic tape cassette of the present invention, a slippery sheet is arranged on the inner surface side of each of the upper and lower cassette halves and wound around a pair of left and right reel hubs. A tape cassette configured to be in sliding contact with an end surface of a magnetic tape is provided with a structure in which a slippery sheet containing a nonionic surfactant is used.

Examples of the nonionic surfactant include fatty acid higher alcohol ethylene oxide adduct, fatty acid higher alcohol propylene oxide adduct, fatty acid ester of glycerin or pentaerythritol, and fatty acid ester of sorbit and sorbitan.

Examples of the material of the slip sheet of the present invention include polyethylene, polyethylene terephthalate, and Teflon, but the material is not particularly limited.

[0008]

According to the present invention, by incorporating the nonionic surfactant into the slip sheet, the anti-static effect of the slip sheet can be maintained, the running stability of the magnetic tape can be improved, and the high temperature and high temperature can be improved. Even when placed in a moist environment, unlike conventional antistatic agents, since it does not contain an ionic component, the ionic component does not elute in water and promotes corrosion. Corrosion from both end surfaces of the magnetic tape used as the magnetic layer is prevented, and the long-term storage reliability of the magnetic tape is sufficiently improved.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged sectional view of a magnetic tape cassette according to an embodiment of the present invention. In FIG. 1, 1 is an upper and lower cassette half, 2 is a reel hub, 3 is a wound magnetic tape, 4 is a front lid, 5 is a back lid, 6 is a magnetic tape pulled out to a lid portion, and 7 is a slippery sheet. is there.

The magnetic tape cassette used was designed based on the 8 mm video standard, and the material used was ABS resin. However, the reel hub is flangeless without the upper and lower flanges. The test magnetic tape has a thickness of 10
Diameter 1 on μm polyethylene terephthalate film
15 pieces of Al ₂ O ₃ fine particles of 00 Å / (μm) ^{2 are} arranged, and further Co-Ni (Co: 80 wt%) 3 is provided along the cylindrical can having a diameter of 1 m in the incident angle range of 90 degrees to 40 degrees. × 1
A magnetic layer obtained by vapor deposition of 0.15 μm in oxygen of 0 ⁻⁵ (Torr) was placed, and a perfluoropolyether (K
RYTOX-157, FS-M (manufactured by DuPont) 5
8 mm tape arranged in nm.

The slippery sheets of the examples of the present invention are obtained by kneading polyethylene with a nonionic surfactant containing polyethylene glycol monolaurate as a main component (Examples 1 to 4), and polyethylene with sorbitan stearin. The thing which kneaded the nonionic surfactant which has acid monoester as a main component (Examples 4-7) was used. The slippery sheets of Comparative Examples (Comparative Examples 8 to 10) were made of polyethylene impregnated with an antistatic agent containing oleyl alcohol phosphate Na salt as a main component, and had a size that could be stored in an 8 mm cassette. It was cut into pieces and used.

Environmental tests were carried out using the tape cassettes of Examples and Comparative Examples. In the environmental test, the obtained magnetic tape cassette was left in an atmosphere of a temperature of 40 ° C. and a relative humidity of 90% for 30 days, then taken out, and a commercially available 8 mm video tape recorder (EV-A30 manufactured by Sony Corporation).
Reproduction was performed at 0), and dropout and clogging were evaluated.

1 with an 8 mm video tape recorder
After repeating the reproduction of 00 times, 3 times in the atmosphere again.
It was left for 0 days, taken out, and subjected to the same evaluation with an 8 mm video tape recorder.

In the dropout evaluation, when the output signal at the time of reproduction decreases by 16 dB or more in a time of 15 μsec or more, it is counted as one, and the number of occurrences in one minute is measured, and the initial value before the test is set. The increase rate with respect to each other was expressed as a multiple. Further, the clogging is the number of cloggings occurring in 60 minutes for 1 second or more.

Regarding the evaluation of running stability, the test piece was left in the above atmosphere for 30 days and then measured with an 8 mm video tape recorder.
After repeating the reproduction of 00 times, the winding state of the magnetic tape on the reel was visually evaluated.

The measurement results are shown in (Table 1).

[0018]

[Table 1]

As is clear from (Table 1), in Comparative Examples 8, 9 and 10 in which the slippery sheet containing the antistatic agent was used, dropouts and clogging occurred more frequently, especially after 100 times of reproduction. The end surface of the magnetic tape was damaged by running,
Due to the high temperature and high humidity atmosphere, the deterioration from the end face was great and the dropout and clogging were remarkable. Further, in Comparative Examples 8, 9 and 10, it was found that the magnetic tape was poorly wound after 100 times of reproduction and the running property was unstable. On the other hand, the magnetic tape cassette using the slippery sheet of the embodiment of the present invention was left in a high temperature and high humidity atmosphere, or after repeated running, there was no significant change in the increase of dropout, and the occurrence of clogging. It was found that extremely high long-term storage reliability was obtained, and stability due to repeated running was good.

[0020]

As described above, in the magnetic tape cassette of the present invention, by containing the nonionic surfactant in the slippery sheet, the running stability of the magnetic tape is improved, and at the same time, the magnetic tape is removed from the end surface of the magnetic tape. It is possible to prevent deterioration and improve corrosion resistance. Further, excellent effects such as the occurrence of dropout, head clogging, and output reduction can be obtained.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a magnetic tape cassette according to an embodiment of the present invention.

[Explanation of symbols]

 1 Upper and lower cassette halves 2 Reel hub 3 Winded magnetic tape 4 Front lid 5 Back lid 6 Magnetic tape pulled out to the lid 7 Sliding sheet

Claims (1)

[Claims] 1. A slippery sheet is arranged on the inner surface side of each of the upper and lower cassette halves, wound around a pair of left and right hubs, and is in sliding contact with the end surface of a magnetic tape having a ferromagnetic metal thin film as a magnetic layer. A magnetic tape cassette, wherein the non-ionic surfactant is contained in the slippery sheet.