JP3235003B2 - Magnetic recording method and magnetic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method and a magnetic recording apparatus, and more particularly to a magnetic recording method and a magnetic recording apparatus capable of improving a reproduction output / medium noise ratio.

[0002]

2. Description of the Related Art In recent years, the demand for higher density in the field of magnetic recording has increased remarkably. In order to achieve this high density, perpendicular recording using a perpendicular magnetic recording medium having an easy axis of magnetization in a direction perpendicular to the recording layer surface, or using an oblique magnetic recording medium having an easy axis of magnetization in a direction oblique to the recording layer surface is used. Oblique recording has been put to practical use.

On the other hand, a recording current whose polarity is inverted every time binary data “1” is generated is supplied to the ring head,
Various methods for recording value data on a magnetic recording medium (for example, NRZI method) are known.

[0004]

The conventional magnetic recording method has a problem that the reproduction output / medium noise ratio is not sufficient. Therefore, an object of the present invention is to provide a magnetic recording method and a magnetic recording apparatus that can improve the reproduction output / medium noise ratio.

According to the magnetic recording method of the present invention, a magnetic recording medium having an easy axis of magnetization in an oblique direction and a ring head having a gap length g1 are relatively moved at a speed v, and binary data "1" is obtained.
In the magnetic recording method of supplying a recording current of which polarity is reversed every time a magnetic field is generated to the ring head and magnetically recording binary data on the magnetic recording medium, the neutralization of reducing the recording current without reversing the polarity is performed. inverting the polarity of the recording current across the level time T, the effective value of the recording current between the neutral level period T, 1 / √ effective value of the recording current other than between the neutral level time T {3} Or 1 / {2} or less and the gap transit time τ = g1 / v
The neutral level time T ≒ τ / 2, for example, T = 0.6
The feature of the configuration is that it is 25τ .

In the magnetic recording apparatus of the present invention, a magnetic recording medium having an easy axis of magnetization in an oblique direction and a ring head having a gap length g1 are relatively moved at a speed v, and binary data "1" is obtained.
In a magnetic recording apparatus that supplies a recording current of which polarity is inverted to the ring head each time a magnetic field is generated and magnetically records binary data on the magnetic recording medium, the neutralization of reducing the recording current without inverting the polarity is performed. Neutral level time control means for inverting the polarity of the recording current with the level time T interposed therebetween;
The neutral level time control means controls the neutral level time T
Is less than or equal to 1 / {3} or 1 / √ of the effective value of the recording current other than during the neutral level time.
{2} or less, and the gap passage time τ = g1 /
v, the neutral level time T ≒ τ / 2, for example,
The feature of the configuration is that T = 0.625τ .

[0007]

According to the magnetic recording method and the magnetic recording apparatus of the present invention, a magnetic recording medium having an easy axis of magnetization in an oblique direction and a magnetic recording medium are provided.
Relative movement at a speed v with a ring head having a tip length g1,
The polarity is inverted each time binary data “1” is generated.
The recording current is supplied to the ring head, and the binary data is
When magnetically recording on a magnetic recording medium , the polarity of the recording current is reversed with a neutral level time T interposed between the neutral level time T for reducing the recording current without reversing the polarity. Is less than 1 / {3} or 1 of the effective value of the recording current other than during the neutral level time T.
/ {2} or less, and the gap transit time τ = g
1 / v, the neutral level time T ≒ τ / 2, eg
For example, T = 0.625τ . As a result of the study by the inventors of the present invention, it has been found that the reproduction output / medium noise ratio can be improved as shown in FIG.

The reason why the reproduction output / medium noise ratio can be improved is not clear, but is estimated as follows. FIG. 1 is a schematic diagram of a magnetic field distribution generated from the ring head 1. When a DC current is applied to the ring head 1, a semi-arc-shaped magnetic field is formed between the magnetic poles R and T with a gap therebetween. The polarity and strength of the magnetic field acting on the magnetic recording medium correspond to longitudinal recording, perpendicular recording, and oblique recording, respectively, as shown in FIGS.
(B) and (c) are obtained. That is, in the longitudinal recording, as shown in FIG. 2A, the polarity of the magnetic field becomes the same near the magnetic pole R and the magnetic pole L, and the strength of the magnetic field is ideally symmetric with respect to the gap center line. (Actually, it becomes asymmetric due to manufacturing variations). On the other hand, in perpendicular recording, as shown in FIG. 2B, the polarity of the magnetic field is reversed between the vicinity of the magnetic pole R and the vicinity of the magnetic pole L, and the strength of the magnetic field is ideally symmetric with respect to the gap center line. (Actually, it becomes asymmetric due to manufacturing variations). In the oblique recording, as shown in FIG. 2C, the polarity of the magnetic field is reversed between the vicinity of the magnetic pole R and the vicinity of the magnetic pole L, and the strength of the magnetic field becomes asymmetric with respect to the center line of the gap.

FIG. 3 is a waveform diagram of a known NRZI recording current. The polarity is inverted each time binary data "1" is generated. FIG. 4 is a waveform diagram of a recording current when the present invention is applied to the NRZI method. The polarity is inverted every time the binary data "1" is generated. However, the polarity is inverted after the recording current is reduced after a neutral level time T. In FIG. 4, the recording current during the neutral level time T is set to the current value 0.

FIG. 5 shows a state immediately before the occurrence of binary data "1". An asymmetric recording magnetic field is formed below the magnetic pole of the ring head. This recording magnetic field is a schematic representation of FIG. 2C. The magnetic recording medium is
It has an axis of easy magnetization in an oblique direction, and is strongly magnetized to the positive electrode under the leading magnetic pole R, and is only slightly magnetized to the negative electrode under the trailing magnetic pole T. Therefore, the magnetic recording medium is magnetized as a positive electrode as a whole, but when passing under the trailing-side magnetic pole T, the intensity of magnetization decreases.

FIG. 6 shows a state immediately after the occurrence of the binary data "1". Immediately after the neutral level time T, the recording current is set to the current value 0. Therefore, no recording magnetic field is formed below the magnetic pole of the ring head, and the magnetization state of the magnetic recording medium maintains the state immediately before.

FIG. 7 shows a state immediately after the end of the neutral level time T. Since the polarity of the recording current is reversed, an asymmetric recording magnetic field having a polarity opposite to that of FIG. 5 is formed below the magnetic pole of the ring head. The magnetic recording medium is strongly magnetized to the negative electrode under the leading magnetic pole R, and is only slightly magnetized to the positive electrode under the trailing magnetic pole T. However, due to the neutral level time T, the magnetized positive electrode in the state shown in FIG. 5 is relatively reduced without being reduced, so that under the trailing magnetic pole T,
Magnetization is strengthened. In addition, the vicinity is an area where the magnetization intensity has not decreased.

FIG. 8 shows a state slightly after the end of the neutral level time T. At the reversal portion of the magnetization polarity where the binary data "1" is recorded, a region having a width WT1 where the magnetization intensity is not reduced is formed, and a region having a width WT2 where the magnetization is enhanced is formed. ing. The width WT1,
It is estimated that the wider the WT2, the better the reproduction output / medium noise ratio.

FIG. 9 shows a state in which the polarity of the recording current is immediately reversed without the neutral level time T immediately after the generation of the binary data "1" (this is a conventional magnetic recording method). ). Since the polarity of the recording current is reversed, an asymmetric recording magnetic field having a polarity opposite to that of FIG. 5 is formed below the magnetic pole of the ring head. The magnetic recording medium has a leading magnetic pole R
Below, the negative pole is strongly magnetized and the trailing side magnetic pole T
Below, only the surface is slightly magnetized by the positive electrode. However, under the trailing-side magnetic pole T, only the surface is magnetized by the negative electrode in the state of FIG. 5 so that it returns to its original state, and is a region where the magnetization intensity is not reduced.

FIG. 10 shows the occurrence (==) of binary data "1".
(Reversal of the polarity of the recording current) (this is a conventional magnetic recording method). A region having a width Wo1 in which the magnetization intensity is not reduced is formed in a portion where the magnetization polarity is inverted where the binary data "1" is recorded. Further, a region having a width Wo2 in which magnetization is enhanced is formed (this is because
This corresponds to the portion between the gap center and the trailing-side magnetic pole T in FIG. 9). The widths Wo1 and Wo2 of these areas are
Compared to FIG. 8, it is narrower.

Accordingly, the widths WT1, W2 of FIG.
It is presumed that T2 is larger than the widths Wo1 and Wo2 in FIG. 10 according to the related art, which is a reason why the reproduction output / medium noise ratio can be improved.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In addition, this does not limit the present invention. FIG. 11 is a main part configuration diagram showing a magnetic recording apparatus according to one embodiment of the present invention. In the magnetic recording apparatus 1000, the rotary cylinder 101 slidingly contacting the magnetic tape 100 is used.
Has a ring head for an 8 mm VTR. A signal processing circuit 102 is connected to the ring head. The signal processing circuit 102 has a neutral level time control unit 103. The neutral level time control unit 103
Supplies a recording current for inverting the polarity at a neutral level time T as shown in FIG. 4 to the ring head, that records binary data on the magnetic tape 100.

[0018] before Symbol neutral level time control unit 103, phosphorus
The gap length of the recording head is g1,
The relative speed of the head is v, the gap passage time τ = g1 /
v, the neutral level time T ≒ τ / 2 , for example,
It shall be the T = 0.625τ. Further, the neutral level time control unit 103 sets the effective value of the recording current during the neutral level time T to 1 / {3} or less of the effective value of the recording current other than during the neutral level time T. or, you below 1 / √ {2}.

[Embodiment 1] A positive / negative rectangular pulse having an amplitude of about ± 10 mA and a pulse width of 2 μs is alternately repeated. It was supplied to a millimeter VTR ring head and recorded on a magnetic tape produced using a vapor deposition device 90 shown in FIG. The neutral level time T is 0.05 μ
s, 0.1μs, 0.2μs, 0.3μs, 0.4μ
s, 0.6 μs and 0.8 μs. The gap length g1 of the ring head is 0.2 μm. The magnetic tape is a vapor deposition tape containing cobalt and cobalt oxide as main components. The axis of easy magnetization of the magnetic layer was inclined by 45 ° with respect to the direction perpendicular to the tape film surface. The relative speed v between the ring head and the tape is 2.5 m / s. Accordingly, the gap transit time τ = gl / v = 0.08 μs, and the neutral level time T = 0.625τ-10τ. For comparison, recording was performed under the same conditions as above except that the neutral level time T was set to 0 μs.

Neutral level time T = 0.05 μs to 0.8
μs and neutral level time T = 0
FIG. 13 shows the result of measuring the reproduction output / medium noise ratio at the recording current value at which the reproduction output is maximum for the magnetic tape recorded in μs. The horizontal axis in FIG. 13 is the neutral level time. The vertical axis is a numerical value based on the case where recording is performed at the neutral level time T = 0 μs. The vertical axis of FIG. 13 shows the reproduction output / medium noise ratio as a numerical value based on the case where recording was performed at the neutral level time T = 0 μs. The medium noise is an integrated noise measured in a band from 0.3 MHz to 10 MHz. From the results of FIG. 13, 0 <T ≦
It has been found that by setting 8τ, the reproduction output / medium noise ratio can be improved. It is presumed that the reason why the neutral level time T has an upper limit is that if the neutral level time T is increased, a non-magnetized area appears and the reproduction output / medium noise ratio is reduced.

Further, from the results of FIG. 13, when the time interval t from when the binary data "1" is generated to when it is generated again is longer than 5τ, 2τ ≦ T ≦ 5τ is set, and the reproduction output is set. It has been found that the improvement of the medium noise ratio can be maximized.

When the time interval t is shorter than 5τ, it is necessary to satisfy 0 <T ≦ t in order to prevent the neutral level time T from being longer than the time interval t. Here, the time interval t is generally because longer than tau / 2, the present invention
In, T ≒ τ / 2, for example, fixed to the T = 0.625τ
I have. Thereby, the complexity of the control for changing the neutral level time T in accordance with the time interval t can be avoided.

[Embodiment 2] Positive and negative rectangular pulses having an amplitude Io of about 10 mA and a pulse width of 0.2 μs are alternately repeated.
Neutral level time T = reducing current from Io to 0
A recording current of 0.05 μs was supplied to an 8 mm VTR ring head, and recording was performed on a magnetic tape manufactured using a vapor deposition device 90 shown in FIG. The current reduction pattern was changed as shown by the curves a, b, c, and d shown in FIG. 14, and the effective value | IT | of the current IT during the neutral level time was changed. The gap length g1 of the ring head is 0.2 μm
It is. The magnetic tape is a vapor deposition tape containing cobalt and cobalt oxide as main components. The axis of easy magnetization of the magnetic layer was inclined by 45 ° with respect to the direction perpendicular to the tape film surface. The relative speed v between the ring head and the tape is 2.5 m / s. Therefore, the gap transit time τ = gl / v = 0.0
8 μs, and the neutral level time T = 0.625τ. For comparison, recording was performed under the same conditions as above except that the neutral level time T was set to 0 μs.

FIG. 15 shows the result of measurement of the reproduction output / medium noise ratio at the recording current value at which the reproduction output is maximized for each magnetic tape recorded by changing the effective value | IT |. The horizontal axis in FIG. 15 is represented by a value | IT | / | Io | obtained by standardizing the effective value | IT | with the effective value | Io | of the current Io in the rectangular pulse portion. The vertical axis represents numerical values based on the case where the recording is performed at the neutral level time T = 0 μs. The medium noise is 0.3 to 10 MHz.
Is the integrated noise measured in the band of. From FIG. 15, | I
It was found that as T | / | Io | is smaller, the reproduction output / medium noise ratio can be improved. Also, | IT | / | Io |
It was found that when ≤1 / {3}, the reproduction output / medium noise ratio could be improved most. Further, | IT | / | Io |
Even when ≤1 / {2}, it was found that the reproduction output / medium noise ratio could be improved sufficiently high.

[Third Embodiment] A positive / negative rectangular pulse having an amplitude of about ± 10 mA and a pulse width of 0.2 μs is alternately repeated, and a neutral level time T of 0.05 mA or less is provided between the two.
A recording current of μs was supplied to a ring head for an 8 mm VTR and recorded on a commercially available high-eight VTR tape.
The gap length g1 of the ring head is 0.2 μm. The high-eight VTR tape is a vapor deposition tape whose main component is a Co-Ni alloy. The axis of easy magnetization of the magnetic layer is inclined by 60 ° to 70 ° with respect to the direction perpendicular to the tape film surface. The relative speed v between the ring head and the tape is 2.
5 m / s. Therefore, the gap transit time τ = gl /
v = 0.08 μs, and the neutral level time T = 0.62
5τ. For comparison, the neutral level time T = 0
Recording was performed under the same conditions as above except that the time was set to μs.

With respect to the magnetic tape recorded at the neutral level time T = 0.05 μs and the magnetic tape recorded at the neutral level time T = 0 μs, the reproduction output at the recording current value at which the reproduction output becomes the maximum, the medium noise, and Playback output /
FIG. 16 shows the result of measuring the medium noise ratio. The results were expressed as numerical values based on the case where the recording was performed at the neutral level time T = 0 μs. The medium noise is an integrated noise measured in a band from 0.3 MHz to 10 MHz. FIG.
As a result, the reproduction output increases by 0.6 dB, the medium noise decreases by 0.6 dB, and the reproduction output / medium noise ratio becomes 1.1.
dB could be improved.

[Embodiment 4] Positive / negative rectangular pulses having an amplitude of about ± 10 mA and a pulse width of 0.2 μs are alternately repeated, and a neutral level time T = 0.05 mA or less between them is 2 mA or less.
The recording current of μs was supplied to a ring head for an 8 mm VTR and recorded on a magnetic tape manufactured using a vapor deposition device 90 shown in FIG. The gap length g1 of the ring head is 0.2 μm. The magnetic tape is a vapor deposition tape containing cobalt and cobalt oxide as main components. The axis of easy magnetization of the magnetic layer was inclined by 45 ° with respect to the direction perpendicular to the tape film surface. The relative speed v of the ring head and the tape
Is 2.5 m / s. Therefore, the gap transit time τ
= Gl / v = 0.08 μs, and the neutral level time T =
0.625τ. For comparison, recording was performed under the same conditions as above except that the neutral level time T was set to 0 μs.

With respect to the magnetic tape recorded at the neutral level time T = 0.05 μs and the magnetic tape recorded at the neutral level time T = 0 μs, the reproduction output at the recording current value at which the reproduction output becomes the maximum, the medium noise, and Playback output /
FIG. 17 shows the result of measuring the medium noise ratio. The results were expressed as numerical values based on the case where the recording was performed at the neutral level time T = 0 μs. The medium noise is an integrated noise measured in a band from 0.3 MHz to 10 MHz. FIG.
As a result, the reproduction output increases by 1.4 dB, the medium noise decreases by 0.7 dB, and the reproduction output / medium noise ratio becomes 1.9.
dB could be improved.

[Embodiment 5] Positive and negative rectangular pulses having an amplitude of about ± 10 mA and a pulse width of 0.2 μs are alternately repeated, and a neutral level time T = 0.05 mA or less between them is equal to or less than 2 mA.
The recording current of μs was supplied to a ring head for an 8 mm VTR and recorded on a magnetic tape manufactured using a vapor deposition device 90 shown in FIG. The gap length g1 of the ring head is 0.2 μm. The magnetic tape is a vapor deposition tape containing cobalt and cobalt oxide as main components. The axis of easy magnetization of the magnetic layer was inclined by 30 ° with respect to the direction perpendicular to the tape film surface. The relative speed v of the ring head and the tape
Is 2.5 m / s. Therefore, the gap transit time τ
= Gl / v = 0.08 μs, and the neutral level time T =
0.625τ. For comparison, recording was performed under the same conditions as above except that the neutral level time T was set to 0 μs.

Regarding the magnetic tape recorded at the neutral level time T = 0.05 μs and the magnetic tape recorded at the neutral level time T = 0 μs, the reproduction output at the recording current value at which the reproduction output becomes the maximum, the medium noise, and Playback output /
FIG. 18 shows the result of measuring the medium noise ratio. The results were expressed as numerical values based on the case where the recording was performed at the neutral level time T = 0 μs. The medium noise is an integrated noise measured in a band from 0.3 MHz to 10 MHz. FIG.
As a result, the reproduction output increases by 1.7 dB, the medium noise decreases by 1.2 dB, and the reproduction output / medium noise ratio becomes 3.0.
dB could be improved.

[Embodiment 6] Positive and negative rectangular pulses having an amplitude of about ± 10 mA and a pulse width of 0.2 μs are alternately repeated, and a neutral level time T = 0.05 mA or less between them is equal to or less than 2 mA.
The recording current with an interval of μs is supplied to a ring head for an 8 mm VTR, and the magnetron sputtering apparatus 14 shown in FIG.
0 was recorded on a perpendicular magnetic recording medium produced. The gap length g1 of the ring head is 0.2 μm.
The perpendicular magnetic recording medium is a magnetic recording medium containing a Co-Cr alloy as a main component. The relative speed v between the ring head and the tape is 2.5 m / s. Therefore, the gap transit time τ = gl / v = 0.08 μs, and the neutral level time T = 0.625τ. For comparison, recording was performed under the same conditions as above except that the neutral level time T was set to 0 μs.

With respect to the perpendicular magnetic recording medium recorded at the neutral level time T = 0.05 μs and the perpendicular magnetic recording medium recorded at the neutral level time T = 0 μs, the reproduction output at the recording current value at which the reproduction output becomes maximum is obtained. FIG. 20 shows the measurement results of the measurement result, the medium noise, and the reproduction output / medium noise ratio. The results were expressed as numerical values based on the case where the recording was performed at the neutral level time T = 0 μs. The medium noise is
This is the integrated noise measured in the band from 0.3 MHz to 10 MHz. As shown in FIG. 20, the reproduction output increased by 2.3 dB, the medium noise decreased by 0.2 dB, and the reproduction output / medium noise ratio could be improved by 2.5 dB.

COMPARATIVE EXAMPLE 1 Positive and negative rectangular pulses having an amplitude of about ± 10 mA and a pulse width of 0.2 μs are alternately repeated, and a neutral level time T = 0.05 mA or less between the two is equal to or less than 2 mA.
The recording current of μs was supplied to a ring head for an 8 mm VTR and recorded on a coating type magnetic tape. The gap length g1 of the ring head is 0.2 μm. The coating type magnetic tape is a magnetic tape in which iron acicular magnetic powder is applied and the easy axis of magnetization is oriented in the longitudinal direction. The relative speed v between the ring head and the tape is 2.5 m / s. Therefore, the gap transit time τ = gl / v = 0.0
8 μs, and the neutral level time T = 0.625τ. For comparison, recording was performed under the same conditions as above except that the neutral level time T was set to 0 μs.

With respect to the coating type magnetic tape recorded at the neutral level time T = 0.05 μs and the coating type magnetic tape recorded at the neutral level time T = 0 μs, the recording current value at which the reproduction output becomes maximum is obtained. FIG. 2 shows the results of measuring the reproduction output, the medium noise, and the reproduction output / medium noise ratio.
It is shown in FIG. The results were expressed as numerical values based on the case where the recording was performed at the neutral level time T = 0 μs. The medium noise is an integrated noise measured in a band from 0.3 MHz to 10 MHz. From the results in FIG. 21, the reproduction output decreased by 0.2 dB, the medium noise increased by 0.3 dB, and the reproduction output / medium noise ratio deteriorated by 0.5 dB. That is, it was found that the reproduction output / medium noise ratio could not be improved with respect to the magnetic tape in which the axis of easy magnetization was oriented in the longitudinal direction even if the neutral level time was provided.

[0035]

According to the magnetic recording method and the magnetic recording apparatus of the present invention, the reproduction output / medium noise ratio can be improved even with the conventional magnetic recording medium and magnetic head. Also,
In oblique Me recording, possible to improve reproduction output / medium noise ratio, it is particularly useful for high density recording.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a magnetic field distribution generated from a ring head.

FIG. 2 is a distribution diagram of polarities and strengths of a longitudinal component, a vertical component, and an oblique component of a magnetic field generated from the ring head of FIG.

FIG. 3 is a waveform diagram of a known recording current of the NRZI method.

FIG. 4 is a waveform diagram of a recording current when the present invention is applied to the NRZI method.

FIG. 5 is an explanatory diagram showing a magnetization state of a magnetic recording medium immediately before generation of binary data “1”;

FIG. 6 is an explanatory diagram showing a magnetization state of a magnetic recording medium at the start of a neutral level time.

FIG. 7 is an explanatory diagram showing a magnetization state of the magnetic recording medium immediately after the end of the neutral level time.

FIG. 8 is an explanatory diagram showing a magnetization state of the magnetic recording medium slightly after the state of FIG. 7;

FIG. 9 is an explanatory diagram showing a magnetization state of a magnetic recording medium when the polarity of a recording current is reversed immediately after the occurrence of binary data “1”.

FIG. 10 is an explanatory diagram showing a magnetization state of the magnetic recording medium slightly after the state of FIG. 9;

FIG. 11 is a main part configuration diagram showing a magnetic recording apparatus according to an embodiment of the present invention.

FIG. 12 is a schematic view of a vapor deposition device used for producing a vapor deposition tape.

FIG. 13 is a characteristic diagram showing a neutral level time T and a degree of improvement in a reproduction output / medium noise ratio.

FIG. 14 is a waveform diagram of a recording current.

FIG. 15 shows the current effective value during the neutral level time and the reproduction output /
FIG. 4 is a characteristic diagram illustrating a degree of improvement of a medium noise ratio.

FIG. 16 is a comparison chart showing measurement results according to Example 3.

FIG. 17 is a comparison chart showing measurement results according to Example 4.

FIG. 18 is a comparison chart showing measurement results according to Example 5.

FIG. 19 is a schematic view of an example of a magnetron sputtering apparatus used for manufacturing a perpendicular magnetic recording medium.

FIG. 20 is a comparative chart showing measurement results according to Example 6.

FIG. 21 is a comparative chart showing measurement results according to Comparative Example 1.

[Explanation of symbols]

 Reference Signs List 1 ring head 100 magnetic tape 101 rotating cylinder 102 signal processing circuit 103 neutral level time control unit 1000 magnetic recording device

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mikio Suzuki 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Hitachi Central Research Laboratory, Inc. (72) Inventor Yasuhiro Kato 1-1280 Higashi-Koikekubo, Kokubunji-shi, Tokyo Hitachi, Ltd. Central Research Laboratory (72) Inventor Naoki Kitagaki 1-1-88 Ushitora, Ibaraki-shi, Osaka Hitachi Maxell Co., Ltd. (72) Inventor Ryo Yano 1-188 Ushitora, Ibaraki-shi, Osaka Hitachi Maxell Co., Ltd. ( 72) Inventor Yoichi Ogawa 1-88 Ushitora, Ibaraki City, Osaka Prefecture, Hitachi Maxell Co., Ltd. (72) Inventor Osamu 1-88 Ushitora 1-Chome, Ibaraki City, Osaka Prefecture, Hitachi Maxell Co., Ltd. (56) Reference Document JP-A-1-269207 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/02 G11B 5/09 311

Claims (4)

(57) [Claims] 1. A recording method in which a magnetic recording medium having an easy axis of magnetization in an oblique direction and a ring head having a gap length g1 are relatively moved at a speed v, and the polarity is inverted each time binary data "1" is generated. In a magnetic recording method in which a current is supplied to the ring head and binary data is magnetically recorded on the magnetic recording medium, the polarity of the recording current is sandwiched by a neutral level time T for reducing the recording current without reversing the polarity. inverting the said neutral level the effective value of the recording current during the time T, 1 / √ effective value of the recording current other than between the neutral level time T
{3} or less, or 1 / √ {2} together to below, gears
When the transit time τ = g1 / v, the neutral level
A magnetic recording method, wherein a time T ≒ τ / 2 . 2. The magnetic recording method according to claim 1, wherein
And the neutral level time T = 0.625τ . 3. A recording method in which a magnetic recording medium having an easy axis of magnetization in an oblique direction and a ring head having a gap length g1 are relatively moved at a speed v, and the polarity is inverted each time binary data "1" is generated. In a magnetic recording apparatus for supplying a current to the ring head and magnetically recording binary data on the magnetic recording medium, the polarity of the recording current is interposed at a neutral level time T for reducing the recording current without reversing the polarity. comprises a neutral level time control means for inverting the neutral level time control means, the effective value of the recording current between the neutral level time T, the effective value of the recording current other than between the neutral level time T 1 / √ {3} or less, or 1 / √ {2} co If below
When the gap passage time τ = g1 / v,
A magnetic recording apparatus wherein a standing level time T 時間 τ / 2 . 4. The magnetic recording apparatus according to claim 3, wherein
And the neutral level time T = 0.625τ .