JPH03154215A - Erasure head - Google Patents

Abstract

PURPOSE:To realize an erasure head with an excellent erasure rate, an excellent distortion rate and less stop noise and erasure noise by providing a magnetization part of the same pole as a final pole at a front face magnetizing part to a part close to a slide circular arc face on a side face of tape retracting side. CONSTITUTION:A multi-pole magnetization part 2 magnetizing plural sets of both N and S poles alternately is provided to a position of a tape slide circular- arc face 1 opposite to a track of a magnetic tape to be erased. Moreover, a retracting side magnetization part 4 is formed to a side face 3 of the tape winding side to a part close to a tape sliding circular-arc face at the same pole as the final pole in the front face magnetization part 2 in a way that the magnetic tape runs in the magnetic field of magnetization. The erasure rate is increased by passing the magnetic tape in the magnetic field of the front face magnetization part 2 and in the magnetic field of the retracting side magnetization part 4 and the distortion rate is improved by passing the tape through a retracting side displacement part 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a permanent magnet erase head for erasing content recorded on magnetic tape.

[Conventional technology]

Conventionally, this type of erasing head has been of the type with a single pole on the front side and no side magnetization, in which only a single pole magnetization is applied to the entire tape sliding arcuate surface corresponding to the track to be erased on the magnetic tape; It is known that there are multi-pole front and non-magnetized side surfaces that are magnetized with only multiple sets of NS bipoles; When comparing the non-magnetized type, the distortion rate is bad for the former, good for the latter,
The S/N and erasure noise are poor in the former and moderately good in the latter, and the stop noise during recording is moderate in the former and poor in the latter.

In addition, as shown in Fig. 4, as a conventional magnet, the tape sliding arcuate surface of an isotropic ferrite magnet is magnetized so that it gradually attenuates in the running direction of the magnetic tape, and then a metal is applied to the same surface. Coated models with multiple poles on the front and non-magnetized sides are also known, but this is convenient because it has a good erasure rate and low erasure noise, but it is difficult to stop or stop during recording.
There were undesirable defects such as large noise.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new erasing head with low stop noise and erasing noise during recording, a good erasing rate, and a good distortion rate.

[Means to solve the problem]

In order to achieve the above object, the erasing head of the present invention has a multi-pole front magnetized part magnetized to a plurality of pairs of NS poles and a plurality of pairs of NS poles on the tape sliding arcuate surface at a position facing the track to be erased on the magnetic tape. , by providing magnetization with the same polarity as the final pole of the front magnetization section at a location near the tape sliding arcuate surface on the side surface on the tape exit side, with the magnetic tape running in the magnetic field of the magnetization. The magnetic tape has a magnetic exit side magnetized portion formed thereon, and the magnetic tape is magnetized with a polarity different from the initial pole in the front magnetized portion at a location close to the tape sliding arcuate surface on the side surface on the tape entry side. A magnet with an entry-side magnetized part formed by running in a magnetized magnetic field.
”ch.ru.

〔Example〕

In the first embodiment of the present invention shown in FIGS. 1 and 2, a plurality of sets of NS and NS poles are alternately magnetized at positions facing the tracks to be erased on the magnetic tape on the tape sliding arc surface (1). The multi-pole front magnetized part (2) and the tape exit side (3)
), a magnetization with the same polarity as the final pole in the front magnetization section (2) is provided at a location close to the tape sliding arcuate surface (1) in a state in which the magnetic tape runs in the magnetic field of the magnetization. The side magnetized portions (4) are formed respectively, and
The second embodiment of the present application shown in FIG. 3 has a tape sliding arcuate surface (
1) is provided with a front magnetized portion (2) similar to the first embodiment, and a side surface (3) on the tape exit side is provided with an exit side magnetized portion (4) similar to the first embodiment. By providing magnetization with a polarity different from the initial pole in the front magnetization section at a location close to the tape sliding arcuate surface on the side surface in such a manner that the magnetic pole tape runs in the magnetic field of the magnetization, the entrance side A magnetized portion (5) is formed therein.

The present invention may be implemented by providing a high magnetic permeability soft magnetic material on the tape entry side of at least one of the magnetic poles on the tape sliding arcuate surface.

[Effect]

As is clear from comparing the Gaussian curve (6) of the conventional example shown in FIG. 4 and the Gaussian curve (7) of the first example of the present application shown in FIG. 7) has an exit side transition part (with magnetic force strengthened by the exit side magnetized part)
8) is observed in the final pole part of the front magnetized part, and the Gaussian curve (6) of the conventional example shown in FIG. 4 and the Gaussian curve M (9) of the second embodiment of the present application shown in FIG. As is clear from the comparison, the Gaussian curve (9
), the exit side transition part (8) and the entrance side transition part li1, whose magnetic force is strengthened by the exit side magnetized part (4) and the entrance side magnetized part (5), are the final pole part of the front magnetized part. recognized in some parts.

The erasure rate is increased by the magnetic tape passing through the magnetic field of the front magnetized part and the magnetic field of the exit side magnetized part, and the distortion rate is improved by passing through the exit side transition part (8), and the distortion rate is improved by passing through the exit side transition part (8). Transition part α1. Stop noise during recording by passing through the
Erasing noise is small (and S/N characteristics are improved).

〔Effect of the invention〕

Since the present invention has the above-mentioned configuration, as is clear from the above-mentioned operation, it has an excellent effect of completely achieving the intended purpose.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the erasing head of the present invention;
FIG. 2 is a Gaussian curve diagram similarly shown in correspondence with the magnetized portion, FIG. 3 is a glass curve diagram showing the second embodiment, and FIG. 4 is a Gaussian curve diagram showing the conventional example. (1)...Tape sliding arcuate surface, (2)...Front side magnetized part, (3)...Side side, (4)...Exit side magnetized part, (
5)...Magnetized part on the entrance side, (7)(9)...Gaussian curve, (8)...Transition part on the exit side, Kanji...Exit part on the entrance side

Claims (1)

[Scope of Claims] 1. A multi-pole front magnetized part magnetized to a plurality of sets of NS poles on the tape sliding arcuate surface at a position facing the track to be erased on the magnetic tape, and a multi-pole front magnetized part on the tape exit side. An exit side attachment formed by providing a magnetization with the same polarity as the final pole of the front magnetization part on the side surface near the tape sliding arc surface with the magnetic tape running in the magnetic field of the magnetization. An erasing head characterized by having a magnetic part. 2. By providing magnetization with a polarity different from the initial pole in the front magnetization section at a location close to the tape sliding arcuate surface on the side surface on the tape entry side, with the magnetic tape running in the magnetic field of the magnetization. The erasing head according to claim 1, further comprising an entrance side magnetized portion formed therein.