JPH0413220A - Magnetic transferring method - Google Patents

Abstract

PURPOSE:To allow the magnetic transfer to make full use of the capacity of a master recording medium formed with a ferromagnetic metallic thin film as a magnetic layer by using a magnetic recording medium formed with the ferromagnetic metallic thin film as the magnetic layer as the master recording medium. CONSTITUTION:The master recording medium formed with the ferromagnetic metallic thin film having >= 1300 oersted coercive force at ordinary temp. as the magnetic layer is heated to 40 to 150 deg.C and is recorded with signals; thereafter, the signals recorded on the master recording medium are magnetically transferred onto a slave recording medium at ordinary temp. Namely, the coercive force HC decreases when the master recording medium formed with the ferromagnetic metallic thin film as the magnetic layer is heated. Sufficient writing is executed and an output is improved when the signals are recorded in this state on the master recording medium. The high potential possessed by the master recording medium is exhibited when the recording signals are magnetically transferred to the slave recording medium by using he master recording medium in such a manner. The high-quality magnetic transfer is thus executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic transfer method for transferring signals recorded on a master recording medium to a slave recording medium while applying a bias magnetic field.

[Summary of the invention]

The present invention uses a magnetic recording medium having a ferromagnetic metal thin film as a magnetic layer as a master recording medium when performing magnetic transfer, and heats the master recording medium during signal recording to reduce the coercive force of the master recording medium. This makes it possible to perform magnetic transfer that makes full use of the capabilities of a master recording medium whose magnetic layer is a ferromagnetic metal thin film.

[Conventional technology]

A method of duplicating a magnetic recording medium on which video signals, audio signals, etc. have been recorded is to stack a slave recording medium on a pre-recorded master recording medium so that the magnetic layers are in close contact with each other, and to ensure good contact. A bias magnetic field is applied to the master recording medium to transfer the magnetic recording on the master recording medium to the slave recording medium. A so-called magnetic transfer method is known.

On the other hand, increasing recording density in the field of magnetic recording.

In order to cope with shorter wavelength recording signals, a ferromagnetic metal thin film is used as the magnetic layer. The development of so-called vapor-deposited tapes is progressing and has already been put into practical use. In this vapor deposition tape, the magnetic properties can be controlled to some extent by introducing oxygen into the vapor deposition atmosphere. For example, when the amount of oxygen increases, the residual magnetic flux density Br decreases slightly, but the coercive force Hc increases and C/ N tends to improve.

Therefore, it is conceivable to utilize this high coercive force Hc to use the vapor-deposited tape as a master recording medium in the above-mentioned magnetic transfer.

However, if the coercive force Hc of the vapor-deposited tape, which is the master recording medium, is set to a sufficiently high value (usually more than twice the coercive force Hc of the slave recording medium. Therefore, about 1300 oerstiff 1: or more), the master recording medium - I've found it difficult to write to. For example, while it is expected that the reproduction output will increase in proportion to the coercive force Hc of the master recording medium, it was actually measured to be approximately 13
It turned out that it would hit a plateau around 00 El Steno 1-.

[Problem to be solved by the invention]

As described above, when a vapor-deposited tape is used as a master recording medium in magnetic transfer, the actual situation is that the high potential of the master recording medium cannot be utilized because signals are insufficiently written to the master recording medium.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and is intended to sufficiently write signals to a master recording medium having a ferromagnetic metal thin film as a magnetic layer.
It is an object of the present invention to provide a magnetic transfer method that enables good magnetic transfer by fully utilizing the ability of a master recording medium having a ferromagnetic metal thin film as a magnetic layer.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a master recording medium whose magnetic layer is a ferromagnetic metal thin film having a coercive force of 1300 oerste nod or more at room temperature. The device is characterized in that after recording a signal by heating it to 150° C., the signal recorded on the master recording medium is magnetically transferred to a slave recording medium at room temperature.

That is, in a magnetic recording medium in which the magnetic layer is generally a ferromagnetic metal thin film, the coercive force Hc decreases as the temperature rises, as shown in FIG. Taking advantage of the fact that the coercive force Hc of a magnetic recording medium serving as a magnetic layer decreases as the temperature increases, signals are recorded while the master recording medium is heated.

At this time, the heating temperature of the master recording medium may be set so that the coercive force Hc of the master recording medium becomes a value that allows sufficient signal recording.

In order to perform sufficient signal recording, it is preferable that the coercive force Hc of the master recording medium is 700 to 1500 Oersted, and therefore the heating temperature of the master recording medium is 40
It is preferable to set the temperature to ~150°C. Heating temperature is 4
If the heating temperature is less than 0°C, the effect of reducing the coercive force will be small; on the other hand, if the heating temperature exceeds 150°C, the skew (track linearity) will deteriorate, causing problems such as deterioration of characteristics due to heating noise of the magnetic head. There is a risk.

In the present invention, since signals are recorded while heating the master recording medium as described above, there is a possibility that deterioration of the shape of the master recording medium due to heating may become a problem.

For example, in a magnetic recording medium whose magnetic layer is a ferromagnetic metal thin film, if the tape becomes deformed (stretched) due to repeated use, it may cause cracks and a noticeable increase in dropouts due to peeling or falling off of the magnetic layer. Therefore, in the master recording medium used in the present invention, a non-magnetic support (on which a ferromagnetic metal thin film is deposited) is used.
It is preferable that the glass transition point Tg of the base film) is 150°C or higher. Specifically, polysulfone (glass transition point Tg 190°C), polyethersulfone (
Glass transition point Tg 223°C), polyetherimide (
Glass transition point Tg 216°C), polyamide (glass transition point Tg 250°C), polyimide (glass transition point Tg 3
50°C) etc. are suitable.

Furthermore, in order to suppress deformation of the master recording medium, it is also effective to increase the mechanical properties of the base film of the master recording medium, specifically, the Young's modulus. In particular, by setting the Young's modulus of the base film to 1000 kg/ms'' or more, it is possible to prevent deterioration of the initial characteristics such as an increase in dropouts caused by shape deterioration and deterioration of the hit waveform.

In the present invention, a ferromagnetic metal thin film is used as a magnetic layer as a master recording medium. Although it is a so-called vapor-deposited tape, it has the above-mentioned characteristics (coercive force Hc i 3 at room temperature
The material of the ferromagnetic metal thin film may be any material as long as it satisfies (1 O Oerstend or more). For example, metals such as Fe, Co, Ni, Fe-Co, Fe-N
i, Co-Ni.

Fe-Co-Ni, Fe-Ca, Co-(, a.

Co-PL, Mn-BiMn--A1. Fe-CrCo
-Cr, N1-CrFe--t-, a-CrCo-Ni
-Cr, ferromagnetic alloys such as Fe-Cc-Ni-Cr, etc.

The slave recording medium is also optional.
Adhesive - Those whose magnetic powder is made of iron oxide, N-boron oxide powder such as FpzOz, and those whose magnetic powder is made of metal magnetic powder made of Fe, Co, Ni, or alloys mainly composed of these (
A so-called metal tape), a magnetic powder made of hexagonal barium magnetic powder, etc. can be used. Among them, a magnetic recording medium using hexagonal barium magnetic powder as the magnetic powder exhibits excellent characteristics as a slave recording medium.

[Effect]

When a master recording medium whose magnetic layer is a ferromagnetic metal thin film is heated, the coercive force Hc decreases. When a signal is recorded on the master recording medium Q in this state, sufficient writing is performed and the output is improved.

When a recording signal is magnetically transferred to a slave recording medium using such a master recording medium, the high efficiency of the master recording medium is fully utilized, and high quality magnetic transfer is performed.

〔Example〕

The present invention will be explained below based on specific experimental results.

We prepared multiple types of master recording media with different coercive forces Hc at room temperature using a Co-Ni based ferromagnetic metal thin film as an eS layer, and investigated changes in playback output by varying the temperature during signal recording. . The frequency of the signal recorded on each master recording medium is 7M1
(z, and the playback output is the measured value at room temperature (25℃
(relative value based on the value when ). The results are shown in Table 1.

Table 1 For a master recording medium with a coercive force Hc of 1050 oersted at room temperature, there is almost no difference in output even if the temperature during signal recording increases, but the coercive force Hc at room temperature
The output of the master medium with a value of 1,500 oersted and 1,700 oersted is increased by heating.

Therefore, for these master media, both when signals are recorded at room temperature and when they are recorded while being heated (70°C), we use a magnetic recording medium that uses barium ferrite powder as the magnetic powder as a slave recording medium. When the transfer was performed and the transfer characteristics were compared, it was confirmed that good transfer characteristics were obtained when signals were recorded while being heated.

In this example, the influence of the glass transition point Tg of the base film was investigated.

The master recording medium used has a magnetic layer made of a ferromagnetic metal thin film with a thickness of 0.2 μm, and its coercive force Hc is 180
0 Oersted, residual magnetic flux density Br is 4500 Gauss,
The thickness of the base film was 10 μm, the thickness of the back coat layer was 0.8 μm, and the tape width was 3.8 μm. The slave recording medium is a coated magnetic tape using barium ferrite as magnetic powder.

Changes in the shape of the master recording medium, changes in the hit waveform, and drop per minute at the initial stage and after the transfer test after changing the material of the base film of the master recording medium having the above configuration and performing the transfer test 1000 times. Changes in out were measured.

The results are shown in Table 2.

Table 2 When polyethylene terephthalate, which has a low glass transition point TH, is used as a base film, shape deterioration and impact waveform changes are significant, and dropout increases significantly. On the other hand, when a material with a high glass transition point Tg such as polyimide or polyamide is used for the base film,
The shape deterioration and hit waveform deterioration were within acceptable ranges, and the increase in dropout was also small.

Example 11''1 The same test as in Example 2 was conducted by changing the Young's modulus by selecting the material and stretching state of the base film.

The results are shown in Table 3.

(The following is a margin.) The writing in Table 3 can be made sufficient, and good magnetic transfer can be performed by making full use of the ability of the master recording medium whose magnetic layer is a ferromagnetic metal thin film.

[Brief explanation of drawings]

Figure 1 shows the ferromagnetic metal IWl! FIG. 2 is a characteristic diagram showing the temperature dependence of coercive force of a master recording medium having a magnetic layer of . As is clear from Table 3, as the Young's modulus of the base film increases, shape deterioration and hit waveform deterioration are improved, and an increase in dropouts is also suppressed.

Claims (1)

[Claims] A master recording medium whose magnetic layer is a ferromagnetic metal thin film having a coercive force of 1,300 Oe or more at room temperature from 40°C to
A magnetic transfer method comprising: recording a signal by heating the master recording medium to 150° C., and then magnetically transferring the signal recorded on the master recording medium to a slave recording medium at room temperature.