JPH01192012A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent sticking of fine suspended particles to a magnetic layer and to prevent deterioration in magnetic characteristics by curving a magnetic recording medium to a recessed shape toward the magnetic layer side, thereby forming said medium. CONSTITUTION:The magnetic recording medium 20 is formed with the magnetic layer 22 on one face of a nonmagnetic substrate 21 and is formed with a protective layer 23 on the other face. The recording medium 20 is formed by curving the entire part thereof to the magnetic layer 22 side. The recording medium 20 exists between a front cap 2 and a rear cap 3 while the medium is held housed in a tape cartridge. Harmful material sin the air, for example, the fine suspended particles contg. sulfur, chlorine, etc., advance into a joint part 36 when a slight spacing is formed in said part by some cause. The adhesion of the fine particles to the magnetic layer 22 and the corrosion of said layer are obviated if the medium 20 is curved to recess to the magnetic layer side. The deterioration in the magnetic characteristics is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape-shaped magnetic recording medium, and particularly to a magnetic recording medium loaded into a magnetic tape cartridge or the like.

[Conventional technology]

On non-magnetic substrates such as plastic films.

For example, magnetic recording media formed with magnetic layers made of metal materials such as iron, cobalt, cobalt-nickel, and cobalt-phosphorus have excellent high-density interconnection characteristics, so they can record and reproduce videos, audio, etc. Widely used in magnetic tape cartridges.

FIG. 4 is an overall perspective view of a conventional 8m video magnetic tape cartridge of this type, FIG. 5 is a partially sectional plan view of the tape cartridge, and FIG. 6 is a front cover of the tape cartridge. Enlarged cross-sectional view of main parts near the rear lid,
FIG. 7 is an enlarged exploded perspective view of the tape support portion and its vicinity in the tape cartridge.

Cartridge case C consists of upper case 1 & lower case lb
It is composed of a case body 1, a front lid 2, and a rear lid 3. Two tape reels 4, 4 are rotatably housed within the case body 1.
A magnetic tape 5 is wound around the case body l, and a part of the magnetic tape 5 is led out to the front side from a tape outlet formed on the front surface of the case body l. As shown in FIG. 6, when the magnetic tape cartridge is not in use, the front side of the lead-out portion of the magnetic tape 5 is protected by the front cover 2, and the rear side is protected by the rear cover 3.

On the other hand, although the magnetic tape 5 is not shown, a magnetic layer made of a metal magnetic material is formed on a non-magnetic substrate such as a plastic film, and as shown in FIG. It faces the wall 10. It is arranged like this.

As shown in FIG. 6, the rear cover 3 has an inclined wall 6 that covers the rear side of the magnetic tape 5, and an upper wall 7 provided horizontally at the upper end of the inclined wall 6. Pins 8 are installed on the left and right sides of the inclined wall 6.
is integrally provided, and its tip is slidably inserted into a substantially S-shaped guide groove 9 formed in the case body 1.

As shown in FIG. 7, this S-shaped guide line 9 connects to an S-shaped edge 31 of a hanging wall 30 sunk at the front of the upper case 18 and a vertical wall 32 provided at the front of the lower case 1b. The S-shaped edges 33 of the two are opposed to each other at a predetermined distance.

On the outside of the vertical wall 32 of the front Iid lower case 1b, a tape support part 34 with a straight cylindrical shape is integrally provided.
As shown in FIG. 5, tape outlet ports 35 are formed between the tape support portion 34 and the vertical wall 10 of the front lid 2 on both sides of the case body 10. When the tape cartridge is not in use, a portion of the magnetic tape 5 drawn out from the tape outlet 35 is supported at both ends by the left and right tape supports 34, 34 described above, and is attached to the front cover 2 as shown in FIG. The vertical wall 10 of the vertical wall 10 is spaced apart from the vertical wall 10 of the vertical wall 10.

A conventional magnetic tape cartridge has the above-mentioned configuration, and as shown in FIG. 6, the magnetic tape 5 is vertically disposed behind the lower end joint 36 of the front cover 2 and rear cover 3. Finally, the recording layer (magnetic layer) formed on the front surface of the magnetic tape 5 faces the joining portion 36.

[Problem that the invention seeks to solve]

However, in conventional magnetic recording media, there is a problem in that the magnetic layer is easily corroded, which deteriorates the magnetic properties.

In this regard, various proposals have been made to perform anti-corrosion treatment, such as by incorporating various anti-rust agents into magnetic recording media.

However, simply applying anti-rust treatment is still insufficient to prevent corrosion. This is because suspended particles (corrosive components) in the atmosphere that are harmful to the magnetic recording medium enter the case through gaps and openings provided in the cartridge case and adhere to the magnetic recording layer.

Taking the above conventional configuration as an example, the joint part 3 between the front cover 2 and the rear cover 3
There is no problem if the parts 6 are always in tight contact with each other, but if there are dimensional variations in each part or if the front cover 2 and the rear cover 3 are not sufficiently closed, minute gaps may be formed in the joint part 36. There are many things that happen. If a gap is formed in the joint 36 in this way, harmful suspended particles in the atmosphere will be entrained in the air and enter the space formed by the front cover 2 and rear cover 3 during storage of the tape cartridge. The recording layer of the magnetic tape 5 (
(magnetic layer) and causes corrosion.

The intrusion of these suspended particles occurs at the joint 3 between the front lid 2 and the rear lid 3.
6, and it has been confirmed that this is noticeable in the vicinity of the tape support portion 34 where the front cover 2 and the lower case lb are joined together and there is a high possibility that a gap will be formed.

Specific examples of such harmful substances in the atmosphere include suspended particles of sulfur, chlorine, and various compounds containing these, and mist-like substances such as sulfur and nitric acid.

In the specification of the present invention, these particles are referred to as floating particles in the atmosphere that corrode the recording medium.

One feature of the present invention is to effectively prevent the recording medium from corroding due to the intrusion of harmful substances in the atmosphere or from increasing dropouts and deteriorating the recording characteristics when installed in a cartridge case or the like. The objective is to provide a magnetic recording medium that can.

[Means for solving problems]

In order to achieve the above object, the present invention provides a magnetic recording medium in which a magnetic layer containing a metallic material is formed on a non-magnetic substrate, which is curved concavely in the direction of the magnetic layer when left standing. This is a characteristic feature.

[For production]

Since the magnetic recording medium with the above configuration has a curved structure, even if it is loaded into a cartridge whose lid on the head facing surface opens and closes, floating particles that enter through the gap in the lid will flow to the back side of the curve, that is, the non-magnetic substrate surface side. Since it can flow out and prevent adhesion to the surface of the magnetic layer, corrosion and dropout of the magnetic layer will not occur.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a cross-sectional view of a magnetic recording medium according to the present invention, and FIG. 2 is an enlarged cross-sectional view of a lid showing an example of the use of the magnetic recording medium according to the present invention in an 8 mm video magnetic tape cartridge.

In FIG. 1, a magnetic recording medium 20 includes a nonmagnetic substrate 21
A magnetic layer 22 made of a metal magnetic material is formed on one surface of the
A protective layer 23 is formed on the other surface of the nonmagnetic substrate 21, and the entire structure is curved concavely toward the magnetic layer 22.

The magnetic recording medium 20 is flat when wound on the reel 4 of the cartridge, and has a restoring force that causes it to curve as shown in FIG. 1 when exposed to the tape drawer.

As the non-magnetic substrate 21, for example, a polyethylene terephthalate film, a polyimide film, a polysulfone film, etc. are used.

Examples of the metal magnetic material include simple metals such as Fe and Go, Co-Ni, Co-CrCo-P,
Co-N1-P, Co-Ni-Fe.

Co-Ni-Cr, Co-Fe, C
o -F e -Cr, Go-Fe-Ni, Co-Ti
, Co-Cu and other alloys are used. Examples of methods for forming the magnetic layer 22 include vapor deposition, sputtering, and CVD.
The present invention is particularly effective in forming a magnetic layer without using a binder. Note that a protective layer can also be formed on the magnetic layer 1-22 using a lubricant or a rust preventive agent.

As the material for forming the protective layer 23, for example, an aliphatic compound, a fluorine compound, a silicone compound, or a hydrocarbon compound is suitably used.

As the aliphatic lubricant, for example, fatty acids, metal salts of fatty acids, fatty acid esters, fatty acid amides, fatty acid alcohols, etc. are used.

As the fluorine-based lubricant, for example, trichlorofluoroethylene, perfluoropolyether, perfluoroalkyl polyether, perfluoroalkyl carboxylic acid, etc. are used.

As the silicone lubricant, for example, silicone oil, modified silicone oil, etc. are used.

As the hydrocarbon lubricant, paraffin, squalane, wax, etc. are used, for example.

Moreover, a rust preventive agent can be added to the protective layer 23 together with a lubricant.

Next, an example in which the magnetic recording medium 2o of FIG. 2 is employed in a magnetic tape cartridge having the structure of FIG. 4 will be described with reference to the partially enlarged view of FIG. 2.

In FIG. 2, the overall structure of the magnetic tape cartridge is the same as that shown in FIG. It is composed of a rear lid 3. Two tape reels 4.4 are rotatably housed in the case body 1, and a recording medium 20 (
A magnetic recording medium 2o is wound thereon, and a part of the magnetic recording medium 2o is led out to the front side from a tape outlet formed on the front side of the case body 1. As shown in FIG. 2, when the magnetic tape cartridge is not in use, the front side of the lead-out portion of the magnetic recording medium 20 is protected by the front cover 2, and the rear side is protected by the rear cover 3.

The magnetic recording medium 20 is loaded so that the magnetic layer 22 is on the front lid 2 side. Therefore, the concave surface of the magnetic recording medium 20 is located on the front lid 2 side.

As shown in FIG. 3, Kl! between the lower part of the front cover 2 and the lower part of the inclined wall 6! 1, the suspended particles will enter the cartridge through the route A shown in the figure. However, since the magnetic recording medium 20 is curved and the lower edge protrudes toward the lid 2, the flow of suspended particles is directed toward the protective layer 23 side. Therefore, floating particles do not flow into the magnetic layer 22 side, and floating particles do not adhere to the surface of the magnetic layer 22, thereby preventing corrosion of the magnetic layer 22 or causing dropouts.

As an example, a magnetic recording medium 20 was prepared by forming an obliquely vapor-deposited magnetic layer with a thickness of xoooA on a polyester film with a thickness of 1Qpm, and further coating and drying a 5Vc protective layer on the back side to a thickness of 7000λ. .

On the other hand, as a comparative example (conventional example), an obliquely deposited magnetic layer with a thickness of 1000λ was formed on a polyester film with a thickness of lQ#m, and a protective layer (
A magnetic recording medium 5, which is always flat and has no restoring force, was prepared by applying and drying a back coat.

The Examples and Comparative Examples prepared above were wrapped in an 8 mm VTR cassette having the shape shown in Fig. 4 and left outdoors for one month, and changes in saturation magnetization σB and dropout were measured. The results shown in Table 1 are encouraging.

Table 1 As is clear from Table 1, according to the present invention, floating particles etc. that have entered through the gap in the lid can flow out to the protective layer side where they do not affect the characteristics of the recording medium, and as a result, the magnetization characteristics And there was almost no decrease in dropout. Therefore, the corrosion resistance and alignment reproduction characteristics of the magnetic recording medium are improved.

In addition, various experiments were conducted regarding the depth of the curved portion of the magnetic recording medium 20, and the best results were obtained when the maximum distance from the flat plate to the tape magnetic surface when left still was between 0.2 and 3 nm. It was done.

[Embodiments of the invention]

As explained above, according to the present invention, a concave curve is formed in the direction of the magnetic layer, so even if a tape cartridge or the like is wound with a tapered part, floating particulates that enter from the outside can can be prevented from adhering to the magnetic layer, and the corrosion resistance and alignment/reproduction characteristics of the magnetic recording medium can be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the magnetic recording medium according to the present invention, FIG. 2 is an enlarged cross-sectional view of the vicinity of the lid of a magnetic tape cartridge using the magnetic recording medium according to the present invention, and FIG. 4 to 7 are cross-sectional views illustrating the intrusion route of suspended particles when there is a gap in the lid, and FIGS.
The figure is an overall perspective view of the magnetic tape cartridge, Figure 5 is a partially sectional plan view, Figure 6 is an enlarged sectional view of the front and rear lids, and Figure 7 is an enlarged exploded view of the tape support area. FIG. 20...Magnetic recording medium, 21...Nonmagnetic substrate, 22...Magnetic layer, 23...Protective layer. 1st ward 21!1 5b65e3W t
. 3rd Ward 4th! ! I No. 5-1! f 61st! i

Claims (2)

[Claims] (1) A magnetic recording medium comprising a magnetic layer containing a metal magnetic material formed on a non-magnetic substrate, characterized in that the magnetic layer is curved concavely in the direction of the magnetic layer. (2) The magnetic recording medium according to claim (1), wherein the depth of the concave portion during the bending is set to 0.2 mm to 3 mm.