KR920001157B1 - Hybrid Magnetic Head - Google Patents

Abstract

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Description

Hybrid Magnetic Head

1 is a schematic longitudinal sectional view showing the structure of a hybrid magnetic head according to the present invention.

FIG. 2 and FIG. 3 are graphs showing the comparison between the ashimmetry for the recording and reproduction current and the ashimmetry characteristics for the erasing current in the present invention and the prior art.

4 is a schematic longitudinal sectional view showing the structure of a conventional hybrid magnetic head.

FIG. 5 is a plan view of the sliding contact surface side of the magnetic recording medium of the magnetic head of FIG.

* Explanation of symbols for main parts of the drawings

10: recording and playback core 11,21: center core

12,22: side core 13: recording and playback gap

14: recording and reproducing coil 20: erasing core

23: erase gap 24: erase coil

30,31: nonmagnetic material 15,25,40: back core

The present invention relates to a composite magnetic head for digital recording and reproduction, and more particularly to an improvement in asymmetry of this kind of magnetic head.

This type of magnetic head integrates a recording / reproducing core and an erasing core, and erases both sides of a recording track recorded by the recording / reproducing core with a pair of erasing tracks to form an inorganic rock band. The form of the dog was known. One of them has a common center core, and both sides of the recording and reproducing and erasing cores are joined to each other, and the other is made of a separate recording and reproducing core and a non-magnetic material interposed therebetween. It is of the form to join. The former has the advantage of being easy to manufacture, but has a problem of large leakage flux (cross feed or cross torque) between the erasing core and the recording / reproducing core. On the other hand, the latter is more difficult to manufacture than the former, but since the magnetic material is interposed between the recording / reproducing core and the erasing core, the crossfeed or crosstalk is small.

In addition, the former has a large asymmetry, and the latter has a small structure. Asymmetry is caused by flowing a DC current through a coil for erasing and an AC current through a coil for recording and reproducing, and the leakage magnetic flux by the DC current for erasing is the same as the direction of the magnetic flux by the AC current for recording. At this moment, the quantum fluxes overlap and the recording magnetic field becomes larger, and when the directions of both magnetic fluxes are different, the quantum fluxes cancel each other and the recording magnetic field becomes smaller. When the recording signal is reproduced in this manner, asymmetry called as asymmetry occurs in the interval between the reproduction signals in places where the recording magnetic field is large and small. Asymmetry is represented by the size of the asymmetrical time ns, and the smaller this value or the smaller the fluctuation range of the operation range, the fewer errors in the recording information can be read, and the higher density recording becomes possible, resulting in higher reliability.

Here, in the former form, in order to reduce the asymmetry, a coil for applying a bias current is separately provided in advance on the recording / reproducing core side, and a bias current is applied to the coil to erase the leakage magnetic flux on the erasing core side. A magnetic head was proposed (Japanese Patent Laid-Open No. 62-65220). However, the provision of a separate bias coil in this way obviously leads to a complicated manufacturing process and an increase in price.

In the latter form, that is, in the case where the recording / reproducing side and the erasing side are magnetically blocked in the form of joining a non-magnetic material through the recording / reproducing core and the erasing core separately, the asymmetry is compared with the former form. It is hard to occur. However, as high-density recording progresses, asymmetry becomes a problem in this format as well.

FIG. 4 shows a conventional composite magnetic head of this magnetic material interposing type, and FIG. 5 is a plan view of the sliding contact surface side of the magnetic recording medium of the magnetic head of FIG. The erasing cores 20 of the recording / reproducing core 10 all have center cores 11 and 21 and side cores 12 and 22, and the center cores 11 and side cores 12 and center cores 21 thereof. ) And a magnetic gap formed between the abutting surfaces of the side cores 22 via a gap forming material constitute a recording / playback gap 13 and a pair of erasing gaps 23, respectively. An inorganic rock band is made on both sides of the recording track recorded by the reproduction gap 13. The recording and reproducing coil 14 and the erasing coil 24 are wound around the side core 12 and the side core 22, respectively, and the center core 11, the side core 12, the center core 21 and the side core are wound. In the opening portion on the side opposite to the magnetic recording medium M of (22), it is closed by the back cores 15 and 25 to form magnetic closing circuits on the recording / reproducing side and the erasing side, respectively.

The recording / reproducing core 10 and the erasing core 20 (the center core 11 and the center core 21 are joined via a nonmagnetic material 30, and the back core 15 and the back core 25 are joined together. Is bonded through the same nonmagnetic material 31.

As described above, it has been conventionally believed that the magnetic shielding between the recording / reproducing core 10 and the erasing core 20 via the nonmagnetic material 30.31 is indispensable for reducing the crossfeed, crosstalk, or asymmetry. .

The present invention aims to reduce the asymmetry in particular in a hybrid magnetic head of the type in which a nonmagnetic material is bonded to a recording / playback core and an erasing core as described above.

In the present invention, it is necessary to magnetically block the cores of the recording / reproducing side and the erasing side in order to reduce crossfeed, crosstalk, or asymmetry. If a series of back cores which are common to the side and the erase side, i.e., having no magnetic material interposed between the recording and reproducing cores and the erasing cores, the asymmetry is improved, and the adverse effects on the cross feed and cross torque are reduced. It is based on the discovery that it does not occur.

That is, the present invention is characterized in that the back cores of the recording / reproducing core and the erasing core are made common to both cores, and provided on the opposite side of the magnetic gap between the recording / reproducing core and the erasing core. Hereinafter, the present invention will be described with reference to the illustrated examples and experimental examples.

1 shows an embodiment of a hybrid magnetic head according to the present invention. This embodiment differs from the conventional example in FIG. 4 only by using the common back core 40 for the recording / reproducing core 10 and the erasing core 20 as the back core. That is, the back core 40 does not have a magnetic material (shield) in the middle part. In Fig. 1, the same elements as in the prior art are denoted by the same reference numerals to simplify the description of the drawings.

In this way, if the back core 40 is made common between the recording and reproducing cores 10 and the erasing cores 20, the reason for the improvement of the sample geometry is not clear. However, the erase flows in the erasing coil 24 anyway. It is understood that part of the magnetic flux generated by the electric current leaks to the recording / reproducing core 10 side via the back core 40, and this leakage magnetic flux affects the improvement of the asymmetry.

In this way, if the back cores were made common, the cross feed and the cross torque were increased. However, as a result, the cross feed and the cross torque were not deteriorated. At least the back cores were used to improve the asymmetry. The advantages for were not offset at all.

2 and 3 respectively show the magnetic head structure (solid line) of the present invention shown in FIG. 1 and the conventional example shown in FIG. Is a characteristic diagram comparing and displaying a magnetic head structure (broken line). From this characteristic diagram, it will be clearly understood that the composite magnetic head according to the present invention has a smaller absolute value of the asymmetry and a smaller variation in the operating range than that of the conventional one.

As described above, the present invention is extremely simple by using a common term for both the recording and reproducing core and the erasing core in the complex term magnetic head in which the recording and reproducing core and the erasing core are interposed with nonmagnetic materials. As a result, the improvement of the asymmetry can be achieved. Therefore, an excellent effect of reducing the asymmetry can be obtained while simplifying the manufacturing process.

Claims (1)

A recording magnetic core having a recording / playback gap having a recording / playing gap, and an erasing core having an erasing core for erasing both ends of a track recorded by the recording / playing-gap through a nonmagnetic material interposed therein, wherein the recording is performed. A hybrid magnetic head comprising a back core of a regenerating core and an erasing core common to both cores, and disposed on opposite sides of the gaps.

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