1. Field of the Invention
The present invention relates to a short wave magnetic recording and reproducing system which can remarkably improve the recording density by arranging a magnetic head such that the direction of magnetization is of a perpendicular or slant direction to the direction of movement of a magnetic recording medium.
2. Description of the Prior Art
FIGS. 1 - 3 illustrate the principles of a conventional magnetic recording and reproducing system.
In FIGS. 1 - 3 a magnetic layer surface of a magnetic reproducing medium 1 is prepared by coating a magnetic layer 3 on a base 2. The magnetic layer surface 3 is positioned to face a magnetic head 4 which is prepared by winding a coil 6 on a core 5 such that the direction of magnetization generated by the coil 6 in a head gap 7 of the magnetic head 4 is arranged in the direction of movement (arrow line) of the magnetic recording medium 1.
In order to record a high frequency signal in the direction of movement of the magnetic recording medium with a high density, it is necessary to decrease the width g of the head gap 7 of the magnetic head 4 or to increase the relative velocity of the recording medium 1 to the magnetic head 4, that is the recording velocity.
In the magnetic head 4, the width g of the head gap 7 can be decreased only to a certain limit. Because of a mechanical work processing, the minimum width g of the head gap 7 may in practice be about 0.6 - 1.0 .mu.m.
The ratio of a/b [a = length of magnetization on the recording medium 1 that is the width of the gap g (a = g) and b = width of a track that is the width w of the core 5 (b = w)] is decreased upon the decreasing of the width of the gap g that is the length of magnetization on the recording medium. However, by decreasing the width of the gap g, the self-demagnetization caused by a diamagnetic field is increased to disadvantageously and remarkably attenuate the reproducing output.
With regard to other losses possible in a short wave recording system, it should be noted that the ratio of a/l(a = length of magnetization and l = distance between the reproducing head 4 and the recording medium 1) is decreased upon the decreasing of the length of magnetization as shown in FIG. 2, whereby the magnetic flux leakage is small and the magnetic flux crossed to the reproducing head 4 is small and the reproducing output is decreased as a spacing loss. Accordingly, in order to record with high density, the recording velocity should be increased. However, it is not easy to move a recording medium such as a magnetic tape having flexibility and elasticity at a high velocity without fluctuation.