JPH01122019A - Signaled magnetic tape - Google Patents

Abstract

PURPOSE:To increase the magnetic transferral efficiency at high density record ing time and to increase a reproducing output by impressing a transferal bias magnetic field from the vertical direction on the magnetic tape whose residual magnetic flux density in the thickness direction is specified. CONSTITUTION:The tape contg. the magnetic powder with a hexagonal ferrite (example: Ba ferrite) particle as the main body and having the magnetic layer whose residual magnetic flux density in the tape thickness direction is >=750G is used as a soft tape. This tape is then superposed on a master tape, the bias magnetic field for transfer is impressed, the signal of the master tape is recorded by transferring it and the title tape is manufactured. Now, the transfer bias magnetic field transfers by impressing in the direction within + or -15 deg. for the vertical direction of the soft tape. The residual magnetic flux density in the longitudinal face inner direction of the title tape is preferably at <=750G.

Description

DETAILED DESCRIPTION OF THE INVENTION [1. Field of Industrial Application] The present invention relates to a signal-containing magnetic tape, and more particularly to a signal-containing magnetic tape recorded at high recording density.

[Conventional technology]

The magnetic transfer method is a method that allows signal-input magnetic tape to be manufactured at low cost. Magnetic transfer is most efficiently carried out when the coercive force of the magnetic tape (hereinafter referred to as soft tape) to which signals are to be transferred is about 1/3 that of the master tape. With conventional soft tape.

7-Fe20s powder etc. were used as the magnetic material.

As the density of magnetic tapes has increased in recent years, soft tapes using hexagonal ferrite particles, which enable high-density recording with relatively low coercive force, have been considered. However, in the conventional magnetic transfer method, the transfer bias magnetic field is mainly applied in the longitudinal direction of the tape, resulting in large demagnetization of the master tape and a small perpendicular magnetization component of the soft tape.

In recording and reproducing short wavelength signals, there has been a problem in that the necessary output cannot be obtained.

[Problem that the invention seeks to solve]

This invention is possessed by the above-mentioned conventional signal type magnetic tape. The object of the present invention is to solve the problem of low output in recording and reproducing short wavelength signals, and to provide a signal type magnetic tape with high recording density characteristics.

[Means to solve the problem]

In the magnetic transfer method, a magnetic recording medium in which magnetic powder with high coercive force is oriented in-plane is used as a master tape. Therefore, in order to reduce demagnetization caused by magnetic transfer of the master tape, it is preferable to apply a transfer bias magnetic field in the direction perpendicular to the tape surface, which is the direction in which erasing of the master tape is difficult. We investigated a signal type magnetic tape that can provide sufficient recording and reproducing output even when a transfer bias magnetic field is applied perpendicularly to such a tape. As a result, hexagonal ferrite particles were used. This soft tape has a perpendicular magnetization component and an in-plane magnetization component, and uses magnetic powder with a higher plate-like ratio than the hexagonal ferrite particles conventionally used, and is dispersed with a high-viscosity binder to achieve high speed. By taking advantage of the fact that the residual magnetic flux density of the soft tape coated with the tape increases in the vertical direction, and by applying a transfer bias magnetic field to the tape from the perpendicular direction, demagnetization of the master tape is small and it can be used during high-density recording. It was discovered that a signal-containing magnetic tape with a large recording and reproducing output can be obtained.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

Soft tapes with different residual magnetic flux densities in the vertical direction were prepared in the manner of primary strips.

A magnetic paint was prepared using barium ferrite particles having a plate ratio different from 3.5.8 according to a conventionally known composition, and the viscosity of the powder was adjusted to a desired residual magnetic flux density in the straight direction. Adjusted from 3 cp to 10 epK. Furthermore, since the speed at which the magnetic paint is applied to the non-magnetic support also affects the residual magnetic flux density in the vertical direction, the application speed is also 20 m/mi.
A soft tape having a desired residual magnetic flux density in the vertical direction was obtained by adjusting it in the range of n to 60 m/mia. The coercive force of the obtained soft tape was 7000e.

Soft tape 1 obtained in this way: coercive force 2
Using a 0000et metal tape as a master tape, the reproduction output of the signal type magnetic tape was determined when a transfer bias magnetic field was applied to the tape surface in the perpendicular and longitudinal directions. This is illustrated in FIG. 1.

Next, two types of soft tapes with a coercive force of 7000e and a vertical residual magnetic flux density of 800G and 700G were used as the soft tapes, a metal tape with a coercive force of 20000e was used as the master tape, and a transfer bias magnetic field was applied. Figure 2 shows the reproduction output of the signal type magnetic tape when the direction was changed.

In addition, the output of a signal-type magnetic tape was transferred by applying a transfer bias magnetic field in the longitudinal direction of the tape using a magnetic tape oriented in the longitudinal direction of the tape using magnetic powder of Co-r-FesOs with a coercive cuff of 000 s. Also shown in Figure 2.

Each of the above magnetic transfer methods uses a metal tape on which a 76 kfcl signal is recorded using a magnetic head made of amorphous magnetic metal as a master tape, and the magnetic surfaces of this master tape and soft tape are aligned.

Press both tapes together using an acrylic jig.

An alternating current magnetic field was applied to this crimped portion.

The conditions for applying the alternating magnetic field were such that the magnetic field was gradually increased to the maximum magnetic field and then gradually decreased until the magnetic field reached 00e.

Soft tape with vertical residual magnetic flux density of 750G,
Magnetic tape is manufactured using magnetic paint with varying magnetic powder content. When the content of magnetic powder increases.

The residual magnetic flux density in the in-plane direction of the tape increases.

Table 1 shows the results of investigating the stealth characteristics of signal type magnetic tapes with different in-plane residual magnetic flux densities.

Still characteristics are the playback time expressed in minutes until the playback output drops 6 dB from the initial output when a signal is recorded on an 811II video deck and the same location on the tape is played back continuously.

〔Effect of the invention〕

As is clear from Figure 1, the residual magnetic flux density in the vertical direction is 7
A signal-input magnetic tape using a barium ferrite magnetic tape of 50 G or more and applying a transfer bias magnetic field from a direction perpendicular to the tape surface has good magnetic transfer efficiency and a large reproduction output.

Figure 2 shows that when using a barium ferrite magnetic tape with a residual magnetic flux density in the vertical direction of 750 G or more, the transfer efficiency is good if the transfer bias magnetic field is applied at an angle of ±15° from the perpendicular direction to the tape surface. There is.

Also, from the table, the residual magnetic flux density in the tape in-plane direction is 750G.
barium ferrite magnetic tape.

It is known to have good durability.

(as explained above) obtained by the present invention. Signal magnetic tapes with a residual magnetic flux density in the vertical direction of 750G or higher and produced by applying a transfer bias magnetic field within an angle of ±15° from the perpendicular direction of the tape surface have good magnetic transfer efficiency even in high-density recording. , it is clear that it has a large playback output.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the relationship between the residual magnetic flux density in the vertical direction of a signal input magnetic tape and the reproduction output when transferring by applying a transfer bias magnetic field vertically and horizontally to the tape surface. FIG. 2 is a characteristic diagram showing the relationship between the direction of application of a transfer bias magnetic field of a signal-containing magnetic tape and the reproduction output of the signal-containing magnetic tape with a constant residual magnetic flux density in the vertical direction. Patent applicant Hitachi Maxell, Ltd. Representative Atsushi Nagai Figure 1: Residual magnetic flux density in the vertical direction Figure 2: Direction of transfer bias magnetic field θ (°)

Claims (2)

[Claims] (1) In a signal-containing magnetic tape produced by overlapping a master tape and applying a transfer bias magnetic field to transfer and record the signals of the master tape,
A magnetic tape comprising a magnetic layer containing magnetic powder mainly composed of hexagonal ferrite particles and having a residual magnetic flux density of 750 G or more in the thickness direction of the tape, and in which a transfer bias magnetic field is applied in the perpendicular direction of the tape. A signal-containing magnetic tape characterized in that it is transferred by applying voltage in a direction within ±15° relative to the magnetic tape. (2) A signal-containing magnetic tape according to claim (1), characterized in that the signal-containing magnetic tape has a residual magnetic flux density of 750 G or less in the longitudinal direction of the tape.