JPS6117281A - Magnetic recording use magnetic disk jacket having electromagnetic wave noise shielding property - Google Patents

Abstract

PURPOSE:To shield a magnetic disk jacket from an electromagnetic wave noise generated from other apparatus by providing a conductive material to the magnetic disk jacket by making it contain, etc. as a layer, a film, or in a shape of particles which can contact to each other. CONSTITUTION:An effect of a shielding property of an electromagnetic wave noise is different in accordance with a strength of an electromagnetic wave noise generating source and a distance to a magnetic recording use magnetic disk, but the shielding property of >=10 decibels is required at least. An electromagnetic wave shielding material 5 having a conductivity is provided to a magnetic disk jacket 2 constituted of a vinyl chloride resin or other thermoplastic resin material 4, in a shape of a film or a layer 6 by means of applying it, sticking it by plating, or by mixing it in a synthetic resin of a jacket forming material, and a jacket is formed. In this way, the electromagnetic wave noise from the outside is attenuated, and the shielding effect can be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic disk jacket for magnetic recording, which has electromagnetic noise shielding properties and is used in electronic computers, peripheral terminal equipment, and the like.

Prior Art Conventionally, as an example of this kind of magnetic disk jacket, the seventh
There was something shown in the figure. In the figure, (1) is the main body that records data on a magnetic disk.

(2) is a jacket that protects the magnetic disk; (3)
is a fibrous tissue body provided on the inner surface of the magnetic disk (magnetic disk jacket c2) to wipe the surface of the magnetic disk (1) and keep it clean, and to reduce friction and friction caused by the rotation of the magnetic disk (1).

Typically, a magnetic disk <1) is coated on one or both sides of a 7j micron thick polyester film with coercive force/Sθ~! θ
θθ Orsted magnetic iron oxide, cobalt-treated magnetic iron oxide, or magnetic chromium oxide with a uniform thickness of 1~
The entire surface is coated to 5 microns.

On the other hand, although the magnetic disk jacket is made of vinyl chloride resin or other thermoplastic resin in the form of a sheet (4) with a thickness of 209 to 250 microns, it does not have electromagnetic noise shielding properties.

Problems to be Solved by the Invention In recent years, electronic computers, peripheral terminal devices, etc. have become widespread in society due to their usefulness. On magnetic recording disks used in these devices, information signals to be recorded are stored in a continuous array of fine magnets (magnetic particles) in a magnetic film via a recording head. Therefore, if a magnetic disk on which data has already been recorded is inadvertently exposed to electromagnetic noise generated by other electrical equipment or equipment that generates magnetism, the data recorded on the magnetic disk will disappear.
or suffer serious injury.

The present invention aims to provide a magnetic recording magnetic disk jacket having electromagnetic noise shielding properties in order to avoid data loss or serious damage recorded on such magnetic recording magnetic disks.

Means for Solving the Problems The present invention provides a magnetic disk jacket (4) made of vinyl chloride resin or other thermoplastic resin material (4) for magnetic recording magnetic disks used in electronic computers, peripheral terminal equipment, etc.
2), applying a conductive electromagnetic wave shielding material (5),
By applying it as a film or layer (6) by plating or mixing it into the synthetic resin of the jacket molding material to form the jacket, the electromagnetic noise of the external cam is attenuated and a shielding effect is achieved. It is something that will be done.

The effectiveness of electromagnetic noise shielding varies depending on the strength of the electromagnetic noise source and the distance from the magnetic recording disk, but shielding of at least lθ decibels or more is required. Usually, the shielding effect is expressed by equation (1).

The present invention will be explained below with reference to examples.

Example 1 It is preferable to use a conductive paint as an electromagnetic wave shielding material that has conductivity. It is uniformly coated on one or both sides of a vinyl chloride resin used for recording magnetic disk jackets by a conventional method and dried. When the solvent evaporates and a coating film (6) is formed, the nickel particles come into contact with each other and develop conductivity. A magnetic disk jacket having an electromagnetic wave attenuation characteristic of 3θ to 60 decibels was obtained by applying a coating material containing nickel particles in an amount such that the resistivity jX'Or'L-on was expressed.

Example 2 A magnetic disk jacket is made of conductive plastic. In this case, the vinyl chloride resin (4) used for the magnetic disk jacket is mixed in advance with metal foil, metal fibers, metal particles (7), or carbon black, or a certain combination, and then formed into a sheet. Mold and form a jacket from this. The vinyl chloride resin mixed with aluminum foil exhibited a specific resistance lθ°Q--, and a magnetic disk jacket with a damping characteristic of 30 to Sθ decibels was obtained.

Example 3 As an example of applying an electromagnetic wave shielding material by metal spraying, wire-shaped zinc was melted with gas or electric arc on a sheet of vinyl chloride resin for a magnetic disk jacket, and compressed air was injected into it. After the particles are made into fine particles, they are sprayed uniformly to a thickness of lθθ to /3θ microns. In this way, a magnetic disk jacket with a damping characteristic of 6.theta. to .theta. decibels was obtained.

Example When applying an electromagnetic wave shielding material to a magnetic disk jacket by dry plating, dry plating is a method of creating metal particles in a vacuum and slamming them onto a plastic substrate. As an example of the present invention, a method using vacuum evaporation is described. Aluminum, which has good conductivity, is used to coat vinyl chloride resin molded into a sheet for a magnetic disk jacket, using a normal evaporation device. Deposit. In the case of a deposited film thickness of 2 microns, a specific resistance of 3j×10 Ω·m was obtained, and a magnetic disk jacket with an attenuation characteristic of θ to θ decibels was obtained.

Example 5 In contrast to Example 2, when wet plating is used, the surface of a vinyl chloride resin formed into a sheet for a magnetic disk jacket is activated by a commonly used method and immersed in a reducing bath containing nickel salt. Nickel is deposited on the surface of vinyl chloride resin. What is the specific resistance of the surface? ;x10
A magnetic disk jacket with a damping characteristic of 30 to θ decibels can be obtained at Ω·偲.

Example: A metal paper containing 3θ% or more of aluminum foil of 1 micron or 20 micron, 23 mx length aluminum fiber in production ratio, which was prepared in advance by another method, was formed into a sheet for a magnetic disk jacket. Adhere it evenly to one side of the vinyl chloride resin using adhesive. The specific resistance of the magnetic disk jacket thus obtained is /X/On
Attenuation characteristics of 30 to θ decibels were obtained at −cm.

As explained above, according to the present invention, the conductive material is applied to the magnetic disk jacket for magnetic recording by including it in the form of a layer, film, or mutually contactable particles. Even if you are exposed to electromagnetic wave noise generated by electricity, electronic equipment, or equipment that generates magnetism, the electromagnetic waves will be attenuated as they pass through the conductor, causing data recorded on the internal magnetic recording disk to disappear. Or, it is a useful invention that can prevent major problems and provide even safer protection.

[Brief explanation of drawings]

FIG. 1 is a front view, partially cut away, showing an example of a magnetic disk jacket for magnetic recording according to the present invention, FIG. FIG. 7 is a partially cut away surface view showing an example of a conventional magnetic disk jacket of this type. (, magnetic disk for magnetic recording, (2)... magnetic disc jacket, (4)... synthetic resin sheet for jacket molding + +53... magnetic wave shielding material, (6)... electromagnetic wave shielding film or Layer, (7)...Metal particles. Fig. 1 Fig. 1 Fig. 3 Fig. 7... Metal particles Fig. 4

Claims (1)

[Claims] 1. A magnetic material having electromagnetic noise shielding properties, characterized in that a conductive electromagnetic wave shielding material is applied to the jacket of a magnetic disk for magnetic recording used in computers, peripheral terminal equipment, etc. Magnetic disc jacket for recording. 2. The magnetic disk jacket for magnetic recording according to claim 1, characterized in that a conductive paint is used as the electromagnetic wave shielding material. 3. Claim 1, characterized in that the jacket body is made of conductive plastic as an electromagnetic wave shielding material.
A magnetic disk jacket for magnetic recording as described in Section 1. 4. The magnetic disk jacket for magnetic recording according to claim 1, characterized in that a metal spray coating is used as the electromagnetic wave shielding material. 5. The magnetic disk jacket for magnetic recording according to claim 1, characterized in that dry plating is used as the electromagnetic wave shielding material. 6. The magnetic disk jacket for magnetic recording according to claim 1, characterized in that wet plating is used as the electromagnetic wave shielding material. 7. The magnetic disk jacket for magnetic recording according to claim 1, characterized in that metal foil is used as the electromagnetic wave shielding material. 8. A magnetic disk jacket for magnetic recording according to claim 1, characterized in that metal paper is used as the electromagnetic wave shielding material. 9. A magnetic disk jacket for magnetic recording according to claim 1, characterized in that a vacuum-deposited metal is used as the electromagnetic wave shielding material.