JPH0658733B2 - Metal thin film type magnetic tape - Google Patents

Description

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

Configuration of Conventional Example and Problems Thereof In recent years, a metal thin film type magnetic tape has been attracting attention as a high density magnetic recording medium and is gradually being put into practical use. It is known that the electromagnetic conversion characteristics of the metal thin film type magnetic tape exhibit extremely excellent characteristics at the time of high density recording as compared with the electromagnetic conversion characteristics of the coating type magnetic tape which has been used conventionally. Generally, in order to obtain excellent electromagnetic conversion characteristics during high-density recording, recording loss and recording loss due to spacing loss occur, and reducing spacing loss is a very important issue. Therefore, it is required to have a smoother surface property than the surface property of the conventional coating type magnetic tape which makes use of the excellent electromagnetic conversion characteristics of the metal thin film type magnetic tape. When a recording wavelength of about 1 μm is used, it is considered desirable that the surface roughness is 500 Å or less in average roughness. When the average roughness of the magnetic layer surface of the metal thin film type magnetic tape is set to 500Å, the surface has a high reflectance because it is a metal material, and it has a metal selection like a polished metal surface, and the surface reflection peculiar to metal. Becomes noticeable. On the other hand, when the magnetic tape is used in a magnetic recording / reproducing apparatus, it is general to detect the end by transmitted light. However, when the surface of the magnetic layer has a metal selection, especially when the running state is unstable. ,
The reflection on the surface of the magnetic layer may cause a malfunction of the end detection. That is, when the magnetic tape is present and the transmitted light should be blocked, the light emitted from the light emitting portion may be reflected by the magnetic layer surface and the surrounding metal object, and may be detected by the light receiving portion to cause a malfunction. is there. As described above, the conventional metal thin film magnetic tape has a high reflectance on the surface, and thus has a problem that it causes a malfunction of the end detection due to the transmitted light.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a metal thin film type magnetic tape which reduces malfunction of end detection due to transmitted light.

Structure of the Invention The present invention is a metal thin film type magnetic tape having a reflectance of 20% or less on the magnetic layer surface side in vertical light reception by diffused illumination with a wavelength of 600 nm, and it is possible to reduce erroneous operation of terminal detection due to transmitted light. It is a thing.

Description of Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the basic structure of a metal thin film type magnetic tape in an embodiment of the present invention. In FIG. 1, 1 is a substrate,
Reference numeral 2 is a metal thin film magnetic layer, and 3 is a surface treatment layer.

Here, as the substrate 1, polyethylene, polypropylene,
The metal thin film magnetic layer 2 is appropriately selected from materials such as polyamide and polyimide, and the metal thin film magnetic layer 2 is CoCr, CoNi, Co, FeCoCr, Ni, Ni-P,
The metal thin film magnetic layer 2 is made of a metal magnetic material such as Co-P or CoNi-P.
It is appropriately selected from conventionally known thin film manufacturing methods such as ion plating and plating. The surface treatment layer 3 is made of a material having a low surface reflectance such as a nitride, an oxide, a carbide, a chloride, a sulfide, and a resin, and is formed by a sputtering method, a vacuum deposition method, a coating method, a CVD method, an ion method. It is appropriately selected from various conventionally known thin film manufacturing methods such as an injection method. As a method of forming the surface treatment layer 3, a part of the metal thin film layer 2 is chemically reacted in an atmosphere gas or a solution,
It can be changed. FIG. 1 shows the most basic constitution. In the present invention, in addition to this constitution, a back coat layer, a lubricant layer, a formation giving layer for controlling the surface shape of the magnetic layer side, a metal thin film layer. It also includes a metal thin film type magnetic tape having various configurations such as other magnetic layers accompanied with the above, an underlayer of the magnetic layer and the like to improve characteristics as a magnetic recording medium.

The surface roughness of the magnetic layer, that is, the surface property of the surface treatment layer 3 is preferably 500 Å or less in average roughness in order to reduce spacing loss and obtain good electromagnetic conversion characteristics. The metal thin film magnetic layer 2 is also 500Å to 300 in order to obtain good electromagnetic conversion characteristics.
A film thickness of 0Å is appropriate. The film thickness of the surface treatment layer 3 is 50 to
500 Å is suitable. If it is 50 Å or less, the surface reflectance cannot be lowered, and if it is 500 Å or more, the electromagnetic conversion characteristics are severely deteriorated due to spacing loss.

The metal thin film type magnetic tape configured as described above has a low reflectance on the surface of the magnetic layer due to the effect of the surface treatment layer 3, and the end detection light may be erroneously received by reflecting the end detection light. Less.

Hereinafter, more specific examples of the present invention will be described.

(Example 1) Using a water-cooled can having a diameter of 500 mm, CoNi (20 w
vacuum deposition of the alloy. Polyethylene terephthalate with a width of 150 mm and a thickness of 15 μm is used as the substrate, and vapor deposition is started from the tangential direction and the running speed is 2 up to a minimum incident angle of 40 °.
It was vapor-deposited at a film thickness of 1500 Å at 0 m / min. After evacuation of the vacuum chamber to 1 × 10 ^-5 Torr using a zirconia crucible as the evaporation source, 150 cc / min of oxygen and 0, 10,
Magnetic tape samples A, B, C, D and E were obtained by introducing sulfur dioxide gas at 20, 30 and 40 cc / min and vapor deposition. Sample A,
A wavelength of 600 nm corresponding to the end detection of a commercially available VHS system or a commercially available 8 mm system VTR on the magnetic layer side surface of B, C, D, E
Diffuse illumination was performed, and the reflected light in the vertical direction was received and measured.
It was 46%, 31%, 22% and 16%. Sample B,
When the surfaces of C, D and E were analyzed, cobalt and nickel sulfides were present on the surface, and the film thickness of the sulfides was 60Å, 100Å, 13 by Auger spectroscopy analysis, respectively.
It was found to be 0Å and 150Å. Samples A to E
The output difference due to recording / reproduction at a recording wavelength of 1 μm was within 1 dB, and showed the same electromagnetic conversion characteristics.

Next, the malfunction test of the end detection was performed using the samples A, B, C, D, and E. The condition for blocking 80% of the light emitted by the light emitting diode was set as the photometric condition, the magnetic layer side was set as the light emitting source side, and the distance between the sample and the light emitting part was 20 mm. . The running speed of the sample tape was 50 cm / min, and the malfunction rate at the time of sudden stop was measured. Each measurement was performed 3000 times, and samples A, B,
The number of malfunctions of C, D and E is 42, 14, 4, 1, 0 respectively.
It was once. These results are summarized in Table 1 and FIG. As is clear from Table 1 and FIG. 2, the malfunction of the end detection is greatly reduced when the reflectance at 600 nm is 50% or less, and is preferably almost 30% or less, more preferably 20% or less.

As described above, according to this embodiment, the malfunction of the end detection of the magnetic tape is prevented by setting the reflectance to 20% or less in the vertical light reception by the diffused illumination of the wavelength of 600 nm on the magnetic layer side surface of the metal thin film magnetic tape. , Can be prevented.

Example 2 An aromatic polyamide having a thickness of 30 μm and an average roughness of 200Å was used as a substrate, and a film thickness of 2000 was obtained by a high frequency sputtering method.
Å Permalloy thin film is formed, and 0.05 on it
Sample F was obtained by forming a CoCr (20 wt%) thin film in an Ar atmosphere of Torr. Sample F was run in a dilute nitric acid aqueous solution having a concentration of 2% to obtain samples G, H, I, J, K, and L. Table 2 shows the dipping time in each dilute nitric acid aqueous solution. Sample G
The reflectance obtained for the standard white plate is summarized in Table 2 by irradiating diffused light having a wavelength of 600 nm on the surface of the magnetic layer of ~ L to receive the reflected light in the vertical direction.

When the surfaces of Samples G to L were analyzed, oxide layers of Co and Cr were observed, and the thickness of the oxide layers was as shown in Table 2.

Further, the number of malfunctions in which the termination detection is performed under the same measurement conditions as in Example 1 is also summarized in Table 2 and FIG. As is clear from Table 2 and FIG. 3, when the reflectance at 600 nm is 50% or less, the malfunction of the end detection is reduced, and preferably 30%, more preferably 20% or less, the malfunction almost disappears.

As described above, according to this embodiment, the reflectance is set to 20% or less in the vertical light reception by the diffused illumination with the wavelength of 600 nm on the magnetic layer side surface of the metal thin film magnetic tape.
It is possible to prevent a malfunction in detecting the end of the magnetic tape.

In this example, the specific effect was shown for the combination of the two types of samples, but it was confirmed that the same effect can be obtained even with the combination of the other materials described above that constitute the present invention. For example, in Example 1, sulfides are produced from sulfurous acid gas, but as reactive gases, in addition to sulfurous acid gas, nitric oxide, nitrogen dioxide, nitrogen, chlorine, silane,
Oxides, nitrides, sulfides, chlorides, and carbides can be produced using conventionally known reactive gases such as ozone, oxygen, and carbon monoxide. In Example 2, the oxide was prepared using dilute nitric acid, but instead of nitric acid, concentrated nitric acid, dilute hydrochloric acid,
Oxides can be made with other oxidizing agents such as concentrated hydrochloric acid, diluted sulfuric acid, concentrated sulfuric acid, hydrogen peroxide solution, potassium dichromate, and the like.
Although the reactive vapor deposition method was used in Example 1 and the immersion in the aqueous solution was used in Example 2, as other methods, reactive sputtering, plasma spraying, atmospheric gas treatment, atmospheric gas heat treatment, CVD method, ion Conventionally known thin film forming methods such as injection method, resin coating, and plasma polymerization can be used. The surface treatment layer can be formed simultaneously with the formation of the metal thin film magnetic layer, or a part of the metal thin film magnetic layer can be modified to form a trace of the metal thin film magnetic layer. It can also be formed on.

EFFECTS OF THE INVENTION As described above, according to the present invention, the malfunction of the end detection of the magnetic tape is prevented by setting the reflectance in the vertical light reception by the diffused illumination of the wavelength of 600 nm on the magnetic layer side surface of the metal thin film magnetic tape to 20% or less. Can be done, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a metal thin film type magnetic tape in an embodiment of the present invention, and FIGS. 2 and 3 are views showing reduction in malfunction of end detection according to the present invention. 1 ... Substrate, 2 ... Metal thin film magnetic layer, 3 ... Surface treatment layer.

Claims (1)

[Claims] 1. A metal thin film magnetic tape having a reflectance of 20% or less on the surface side of a magnetic layer in vertical light reception by diffuse illumination having a wavelength of 600 nm.