JPH0248946B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital magnetic recording method, and particularly to a static digital magnetic recording method.

In recent years, the spread of digital magnetic recording media has been remarkable.
Cash cards, magnetic passbooks, magnetic commuter passes, and magnetic tickets are relatively large devices, while magnetic cards for external memory of home appliances that use microcomputers are relatively small devices. Recording on these magnetic recording media is carried out by providing a relative speed between the magnetic head and the recording medium using a medium conveying method or a magnetic head driving method, and by passing a recording current through the magnetic head. In this method, a recording current obtained by modulating a binary data signal using a certain modulation method is applied to the magnetic head so as to have a certain recording density. However, this method requires a mechanism for feeding the magnetic head or the recording medium in order to provide a relative speed between the magnetic head and the recording medium. Furthermore, the feed rate requires precision and stability to prevent jitter. This makes the device complex and
Become larger. Further, since the recording medium and the magnetic head slide during recording and reproduction, it is necessary to constantly maintain the magnetic head to prevent wear and stains, and the durability of the recording medium also becomes a problem due to abrasion.

As a means to solve these problems, there is a method of recording and reproducing data while keeping the magnetic head and magnetic recording medium stationary. Conventionally known static magnetic recording methods include magnetic transfer methods such as contact magnetic transfer and thermomagnetic transcription, and thermomagnetic writing methods using lasers and the like.

In the magnetic transfer method, the magnetic transfer itself can be said to be static magnetic recording, but since the master is recorded using the conventional method, that is, with a relative velocity between the magnetic head and the magnetic medium, it cannot be said to be completely static magnetic recording.

In addition, in the contact magnetic transfer method, the coercive force of the master must be at least 2.5 times that of the slave, which is not only limited by the magnetic material, but also poses a problem of saturation of the magnetic head when recording on the master.

The thermomagnetic transfer method is currently limited to chromium dioxide (CrO ₂ ) as the magnetic material for the slave, and is not common.

The method and materials for the thermomagnetic writing method are still in the research stage, and the technology has not been sufficiently established. Moreover, since the method is significantly different from conventional methods, it requires a huge amount of cost to introduce it.

Therefore, we will now consider static magnetic recording by maintaining the same correspondence between data and magnetization as in conventional recording methods. The conventional magnetization method is one in which the magnetic layer is saturated magnetized in either the positive or negative direction in response to the modulation waveform of binary data.

FIG. 1 of the accompanying drawings schematically shows a conventional example in which a magnetic head and a magnetic recording medium are held stationary relative to each other to perform digital recording using such a magnetization method. This magnetic head array 1 is made up of a plurality of minute magnetic heads arranged at minimum bit intervals, and in FIG. 1, only magnetic heads 2, 3, 4, and 5 are shown completely. It is only shown in its current state. magnetic head 2, 3,
4 and 5 are of the same construction, each consisting of cores 2A, 3A, 4A and 5A with gaps and write windings 2B, 3B, 4B and 5B wound around the cores. Such a magnetic head array 1
To explain the case of performing static digital magnetic recording using the NRZI method (Non Return to
To record on a magnetic recording medium (Zero Change for One), as shown in FIG. A write current corresponding to the modulation waveform of the digital data as shown in FIG. B may be caused to flow through each write winding of the magnetic head. That is, a current is applied to the write windings 2B and 4B in a direction such that the magnetization is in the direction shown by the arrow A in FIG. A current is passed in a direction that produces magnetization in the direction shown in . The state of magnetization in the magnetic layer 6 in this case is schematically shown in FIG. 2C. When the magnetic recording made in this way is read using a normal magnetic flux differential type magnetic head, a read voltage as shown in Fig. 2D is generated, and if this is combined with a synchronization signal as shown in Fig. 2E, , as shown in FIG. 2F, the recorded digital data "1111" can be read out. However, the magnetic recording method using such a magnetic head array has the following disadvantages. That is, for example,
In the NRZI method, when the digital data to be recorded is continuous binary data 0 such as "0000" as shown in Figure 4A, the write current corresponding to the modulation waveform of this digital data is as shown in Figure 4B. Correspondingly, magnetic recording must be performed such that the magnetization state of the magnetic layer is as shown in Figure 4C, but the magnetic head arrangement as shown in Figure 1 is required. If the coil body 1 is used, as shown in FIG. 3, there is no choice but to flow current in the same direction to each of the write windings 2B, 3B, 4B and 5B in correspondence with the write current shown in FIG. 4B. In this case, the magnetization of the magnetic layer 6 is as shown by arrow B in FIG.
As shown in Figure D, this does not result in unidirectional saturation magnetization with no magnetic flux reversal as shown in Figure 4C, but instead creates a number of magnetic poles in between. Even if the data is played back, the recorded data "0000" cannot be read out accurately.

An object of the present invention is to provide a static digital magnetic recording method that can solve the above-mentioned problems.

In the conventional recording method, the entire magnetic layer is always saturated magnetized in either the positive or negative direction in accordance with the modulation waveform corresponding to the digital data to be recorded, whereas the static digital magnetic recording method according to the present invention For example, magnetic recording is performed by magnetizing the magnetic recording medium by exciting only the magnetic head corresponding to the position where the polarity of the modulated waveform of the digital data to be recorded is reversed.

Next, the present invention will be described in detail regarding embodiments of the present invention based on FIGS. 5, 6, and 7 of the accompanying drawings.

FIG. 5 schematically illustrates one example of a magnetic head for use in implementing the digital magnetic recording method of the present invention. The magnetic head 7 shown in FIG. 5 includes a core 8 having a gap 10 with a gap length of 30 microns, and a write winding 9 wound around the core 8. The shape of the gap 10 is formed between a thin core end 8A and a thick core end 8B for reasons described later. The magnetic head 7 in FIG.
Multiple pieces (six pieces in this example) as shown in Figure 6.
When arranged side by side, a magnetic head array 11 for carrying out the magnetic recording method of the present invention is constructed. In the magnetic head array 11 of this embodiment, the magnetic heads 7 are arranged at 1 cm intervals. Using this magnetic head array 11, for example, digital data "101011" as shown in FIG. 7A is written onto the magnetic layer 12 of a magnetic recording medium.
A case of static recording according to the present invention using the NRZI method will be explained. The modulation waveform of the digital data to be recorded according to the NRZI method is as shown in FIG. 7B, and according to the method of the present invention,
Only the magnetic head corresponding to the position where the polarity of the modulation waveform is reversed is excited. Therefore, with the magnetic head array 11 pressed and fixed to the magnetic layer 12 of the magnetic recording medium as shown in FIG. 6, only the magnetic heads 7A, 7C, 7E, and 7F are turned in the direction in which their polarities are reversed. It is sufficient to excite it with a write current in the corresponding direction. At this time, the magnetization state of the magnetic layer 12 obtained is as shown in FIG. 7C, and diagrammatically shown in FIG. 7D. When the magnetic layer recorded in this way is reproduced using a normal magnetic flux differential type magnetic head, an output voltage as shown in FIG. 7E is obtained, and this output voltage waveform is as follows.
If the output waveform obtained by the conventional recording method is sufficiently compatible and is used together with a synchronization signal as shown in FIG. 7F, as shown in FIG. 7G,
The recorded digital data "101011" can be read out accurately. When the magnetic properties of the magnetic layer 12 are a coercive force of 310 Oe, a residual magnetic flux of 1.3 Maxwell/cm, and a squareness ratio of 0.80, the write current is a DC current of 30 mA, and the feeding speed of the magnetic layer 12 during reproduction is 19 cm/sec. The playback output as shown in Figure 7E is 8V.
It was hot.

Since the gap 10 of the magnetic head 7 of the magnetic head array 11 in the above-described embodiment is formed by the core end portions 8A and 8B having mutually different thicknesses, the magnetization of the magnetic layer 12 is as follows. As shown in Figure 7C, it is asymmetrical, with one side of the maximum magnetization attenuating steeply and the other side attenuating slowly, and this is different from the output waveform obtained by the conventional recording method. This is preferable in terms of obtaining compatible playback output.

As is clear from the foregoing, according to the recording method of the present invention, only the magnetic head corresponding to the position where the polarity of the modulated waveform of the digital data to be recorded is reversed is magnetized.
Even when the digital data to be recorded is a series of binary coded data 0 such as "0000", the above-mentioned inconvenience does not occur at all.

In the above example, the minimum bit interval is 1 cm, but the minimum bit interval for ordinary magnetic cards and magnetic passbooks is 1 cm.
60μ or more, and magnetic commuter passes are used at about 1mm. For this level of recording density, the magnetic recording method of the present invention can be fully implemented using a finely machined magnetic head or a thin film magnetic head. Further, as long as the correspondence between data and magnetization is according to the method of the present invention, the magnetization method does not need to be a magnetic head having a gap as described above, and can be carried out using any suitable means.

According to the magnetic recording method of the present invention, there is no need for a drive mechanism for the magnetic head or the recording medium, and it is sufficient to simply stamp a block in which the magnetic head or components having a magnetization function are integrated onto the recording medium. Furthermore, if a magnetic flux response type magnetic head is used as the reproduction head,
Stationary magnetic recording and reproducing becomes possible for both recording and reproducing.
Therefore, the device can be made smaller, and the wear resistance of the magnetic head and the durability of the magnetic recording medium are dramatically improved.

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings is a schematic diagram showing an example of recording certain digital data by a conventional static magnetic recording method, FIG. 2 is a diagram for explaining the recording and reproducing state of FIG. 1, and FIG. FIG. 3 is a schematic diagram showing an example of recording digital data different from that shown in FIG. 1 by a conventional static magnetic recording method, and FIG. 4 is a diagram for explaining the recording and reproducing state of FIG. 3. , FIG. 5 is a schematic diagram showing an example of a magnetic head used to carry out the magnetic recording and reproducing method of the present invention, and FIG. FIG. 7 is a schematic diagram showing an example of implementing the magnetic recording method of the invention, and is a diagram for explaining the recording and reproducing state of FIG. 6. 7... Magnetic head, 8... Core, 8A, 8B...
... core end, 9 ... write winding, 10 ... gap, 11 ... magnetic head array, 12 ... magnetic layer of magnetic recording medium.

Claims (1)

[Claims] 1. A magnetic head array formed by arranging a plurality of minute magnetic heads at a minimum bit interval and a magnetic recording medium in a state where they are relatively stationary and facing each other, and A digital magnetic recording method for recording digital data, wherein the polarity of the modulation waveform of the digital data to be recorded is reversed in the minute magnetic heads of the magnetic head array when recording the digital data. A digital magnetic recording method characterized by magnetizing an opposing position of the magnetic recording medium by exciting only a minute magnetic head corresponding to the position. 2. The minute magnetic head of the magnetic head array has a head gap in which core end portions having different thicknesses face each other, so that the magnetization is centered on the maximum magnetization portion on one side. Claim 1: The first side is asymmetrical so that the other side attenuates slowly.
Digital magnetic recording method described in Section 1.