JPS6266409A - Magnetic recording and reproducing head device - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording and reproducing head device capable of miniaturization and high density by providing a coil for generating DC magnetic flux to the 1st side core and making a DC current flow so as to cancel the leakage magnetic flux based on an erasure coil through the 1st side core. CONSTITUTION:A value from a magnetic flux quantity flowing to the 1st side core 1a from an erasure head 2 by the definite element method is nearly 11.5%. Then the DC current being 11.5% of the signal recording current flows to a DC magnetic flux generating coil 22 to obtain the recording magnetic field distribution of a center position of a medium by the computer simulation. The asymmetricity of the recording magnetic field is reduced remarkably by the effect flowing a DC current to the coil 22 in this way and it is possible to make the degree of the asymmetricity nearly zero by selecting an optimum DC current flowing to the coil 22. Thus, the magnetic recording and reproducing head device possible for miniaturization and high density with high reliability is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic recording/reproducing head device.

In particular, the present invention relates to a head device suitable for a flexible disk device.

[Conventional technology]

The following will explain the head device of a flexible disk device as an example. @ Fig. 7 is a cross-sectional view showing a conventional head device for a flexible disk. 1 center core (1b
) are opposed to each other with a first magnetic gap (1c) interposed therebetween.

(2) is an erasing head with a second side core (2a) and a second side core (2a).
The center core (2b) faces each other with a second magnetic gap (2c) interposed therebetween. (3) is a non-magnetic material for magnetically separating both heads [11, +21. A recording/reproducing coil (6) through which a signal recording current flows is wound around the first side core (1a), and an erasing coil (7) through which an erasing DC current flows around the second side core (2&). Tei name.

The magnetization (5) recorded on the medium (4) by the recording/reproducing head 111 in a width wider than the track width is erased by the erasing head (2).
The tunnel is erased and the recording remains with the original track width. At this time, the recording/playback head (1) and the erasing head (
2) Both coils (6) and (7) are energized at the same time.

Therefore, the recording/reproducing head 11+ and the erasing head (2
) is required to magnetically separate the non-magnetic material +3). However, as the density of recording continues to increase, the distance between the recording gap and the erase gap is required to be small due to the recording format on the medium, and on the other hand, the size of the head is becoming smaller.
Productivity.

Needless to say, in consideration of cost reduction, it is desirable to eliminate such separation and integrate both heads.

[Problems to be solved by the invention] However, both center cores (1b) (2b) remain the same as before.
If the non-magnetic material (3) between the two is removed, the following problem will occur.

As shown in FIG. 8, an alternating current signal recording current flows through the recording/reproducing head (1), and the magnitude of the signal magnetic field changes depending on the relative direction of the current. In other words, Fig. 8 (
In a), the direction of the direct current flowing through the erasing coil (7) of the erasing head (2) and the direction of the alternating current flowing through the recording/reproducing coil (6) of the recording/reproducing head (1) are reversed. ing. In this case, the leakage magnetic flux (8) leaking from the erasing head (2) based on the DC current to the recording/reproducing head port 1 and the magnetic flux of the recording/reproducing head (1)
They are oriented in the same direction in the first side core (1a) of the reproducing head (reading head opening), and the signal writing magnetic field becomes large. On the other hand, as shown in FIG. 8(b), the erasing coil (7) of the erasing head (2)
) and the direction of the direct current flowing through the recording/reproducing head 11.
When the directions of the alternating currents flowing through the recording/reproducing coil (6) of No. 1 are the same, the erasing head (
2) to the recording/reproducing head (1).
8) and the magnetic flux (9) of the recording/reproducing head +11 are in opposite directions in the first side core (1a) of the recording/reproducing head (1), and the signal writing magnetic field becomes smaller.

FIG. 9 shows the strength and distribution of the recording magnetic field at the center position of the medium in the cases of FIGS. 8(a) and 8(b) obtained by computer simulation using the finite element method.

As is clear from this figure, the distribution and strength of the recording magnetic field are very different in each case. Further, FIG. 10 shows the generated sensitive field of the recording head (1), which was also obtained by finite element method computer simulation.9For example, suppose that the coercive force of the medium is 630 Oersted and the magnetization is reversed at that value.

Figure 11 (1st interval for aJ signal recording current interval of 41
Magnetization as shown in Figure 1(b) remains, and Figure 111(c)
As shown in FIG. 3, an asymmetry occurs in the interval P2 of the reproduced signals corresponding to the interval 41, respectively. This phenomenon will hereinafter be referred to as asymmetry. Such asymmetry of the reproduced signal causes a reading error of recorded information, which is undesirable from the viewpoint of high-density recording and reliability.

This invention was made to solve the above-mentioned problems, and it is possible to eliminate the magnetic separation of the center core, and also to significantly reduce the asymmetry of the signal spacing when the magnetic separation is removed. The object of the present invention is to obtain a magnetic recording/reproducing head device that can be downsized and increased in density.

[Means for solving problems]

A magnetic recording/reproducing head device according to the present invention.

A coil for generating DC magnetic flux is installed in the first side core.

By passing a direct current through this, leakage magnetic flux caused by the erasing coil passing through the first side core is canceled out.

[Function] In this invention, a coil for generating DC magnetic flux is provided in the first side core, and by passing a DC current through the coil, the first
Since leakage magnetic flux caused by the erasing coil passing through the side core is canceled, fluctuations in the recording magnetic field are reduced, and asymmetry in signal intervals is reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a cross-sectional configuration diagram explaining one embodiment of the present invention. In figure 1, Qυ is a center core shared by the recording/reproducing core and the erasing core, and (c) is the erasing coil passing through the first side core. This is a DC magnetic flux generating coil that supplies DC current to cancel the leakage magnetic flux caused by

FIG. 2 is a simple equivalent magnetic circuit for calculating the value of the DC current flowing through the DC magnetic flux generating coil (A). i1
9 is the magnetic resistance R of the center core, (12 is the magnetic resistance "R/V" of the first side core (1a), and 12 is the magnetic resistance Rg of the first magnetic gap of the recording/reproducing head 111.

Here, the amount of magnetic flux flowing into the first side core (1a) from the erasing head (2) is about R3 of the magnetic flux generated from the erasing coil (7). - For example, parameters as shown in FIG. 3, i.e. l-6a, m-6174, n-Q, 8t
When calculated with m, R-5,92X10 /,,o(1
/H).

RI, /v+ Rg+ Rc-6,87X 10ro. (
1/Il), and the first side core (
1) The leakage magnetic flux of the erasing coil passing through can be canceled. The value determined by the finite element method is also about 11.5%. Therefore, a DC current of 11.5% of the signal recording current is passed through the DC magnetic flux generation coil (2), and the recording magnetic field distribution at the center position of the medium is calculated by computer simulation for both the states shown in Figure 8 (eL) and (b). Figures 4 and 5 are the results obtained by this method. As described above, by the effect of flowing a DC current through the DC magnetic flux generating coil 4, the asymmetry of the recording magnetic field can be significantly reduced. -For example, if the coercive force exceeds 6300o, the magnetization is reversed, and the degree of asymmetry is determined.

The inner circumference of the 3.5-inch flexible disk (
r-23,188m+) and 8700 bpi (bit
per 1 nch) recording density N RZ
(none return zero) ototo
The calculated values for the t signal are shown in Table 1.

Table 1 Furthermore, by optimally selecting the value of the DC current flowing through the DC magnetic flux generating coil (2), it is possible to reduce the degree of asymmetry to almost zero.

Next, Fig. 6 shows the results of actual measurement of the effect of the DC current applied to the DC magnetic flux generating coil (2).

In this example, if there is no DC magnetic flux generating coil, 16
The asymmetry, which was longer than 0+1 seconds (stage shift), could be reduced to about 25+1 seconds by passing a DC current of about 14 inches of the signal recording current through the DC magnetic flux generation coil. In addition,
It is clear from this example that it is effective to flow a direct current of 5 to 25% of the signal recording current through the direct current magnetic flux generating coil.

〔Effect of the invention〕

As described above, according to the present invention, the first side core is provided with a coil for generating DC magnetic flux, and by passing a DC current through the coil, leakage magnetic flux caused by the erasing coil passing through the first side core is canceled out. , since the asymmetry of the signal spacing when the magnetic separation of the center core is removed can be greatly reduced, the magnetic separation can be removed.
In addition to being able to obtain an inexpensive magnetic recording/reproducing head device.

This has the effect of providing a highly reliable magnetic recording/reproducing head device that can be made smaller and more dense.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram of a magnetic recording/reproducing head device according to an embodiment of the invention, FIG. 2 is an equivalent magnetic circuit diagram according to an embodiment of the invention, and FIG. 3 is an embodiment of the invention. FIG. 4 is a cross-sectional configuration diagram of a magnetic recording/reproducing head device used for analysis according to an embodiment, and FIG. 4 is a magnetic field distribution diagram according to an embodiment of the present invention.
FIG. 5 is a magnetic field distribution diagram according to an embodiment of the invention, and FIG. 6 is a measurement diagram showing the relationship between direct current and asymmetry in an embodiment of the invention. FIG. 7 is a cross-sectional configuration diagram showing a conventional magnetic recording/reproducing head device. Figure 8 is a diagram explaining the flow of magnetic flux when the non-magnetic material between the center cores is removed in a conventional magnetic recording/reproducing head device, and Figures 9 and 10 are magnetic field distribution diagrams in the conventional head device. , Figure 11 (a), (b),
(C) relates to a conventional head device, (a) is a current waveform diagram of a signal recording current, (b) is a diagram explaining recording magnetization of a recording medium, and (C) is a diagram explaining a reproduction signal. . (1)...recording/reproducing head, (Ia)...first side core, (IC)...th [magnetic gap, (
2) Erasing head I (2a) Second side core, (2c) Second magnetic gap, (6)...
Recording/reproducing coil, (7) Erasing coil, Qυ
. . . Center core, (2) . . . DC magnetic flux generation coil. In Figure 9, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A recording/reproducing head in which a center core and a first side core face each other via a first magnetic gap, and a recording/reproducing coil through which a signal recording current flows is wound around the first side core;
And the above center core is shared and the above center core and the second
The side cores have an erasing head that faces each other through a second magnetic gap and has an erasing coil wound around the second side core through which an erasing DC current flows, and leakage magnetic flux based on the DC current of the erasing coil causes the recording and erasing. In a magnetic recording/reproduction head device that passes through the first side core of the reproduction head, a coil for generating DC magnetic flux is provided in the first side core, and by passing a DC current through this, leakage due to the erasing coil passing through the first side core is eliminated. A magnetic recording/reproducing head device characterized by canceling magnetic flux. (2) The value of the DC current flowing through the coil for generating DC magnetic flux is
The magnetic recording/reproducing head device according to claim 1, wherein the magnetic recording/reproducing head device has a magnitude of 5 to 25% of the signal recording current.