JPS5944685B2 - magnetic recording and reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing device using a magnetic recording medium having a plurality of magnetic layers.

2. Description of the Related Art Signal recording and reproduction using magnetic tape has been widely used in the fields of audio, images, electronic computers, and the like.

This is considered to be due to various advantages such as easy recording and erasing, especially easy rewriting, and high-density recording. Therefore, with the development of audio equipment, image equipment, electronic computers, etc., its uses are expected to expand further, and even higher density is expected in the future. The present invention has been made in view of such demands, and uses a multilayer recording medium, that is, a magnetic recording medium consisting of multiple magnetic layers, as a recording medium, and efficiently records different information signals in each of the multilayer magnetic layers. death,
It is an object of the present invention to provide a magnetic recording/reproducing device that can perform reproduction separation and simultaneously check whether or not the recording medium itself is a regular one.

A major feature of the present invention is that a multilayer magnetic recording medium is used as described above, and when recording different information on each of the multilayer magnetic layers, at least one magnetic layer has multiple recording surfaces. For example, signals of different polarities are recorded on the plurality of recording tracks.

This makes it possible to perform high-density recording, and at the time of reproduction, information in each layer can be efficiently reproduced and separated. Another feature of the present invention is that by comparing recorded information and reproduced information and checking for differences between the two, it is possible to determine whether or not the recording medium is genuine. be. This makes it possible to immediately discover a recording medium that has been forged by, for example, transcription, and can significantly increase the reliability of personal identification cards and the like. Hereinafter, details of the present invention will be clarified with reference to embodiments shown in the drawings.

First, the schematic structure of the present invention will be explained with reference to FIG. The recording information given to the terminal 1 is recorded in the recording information memory 3 via the OR gate 2. The information recorded in this memory 3 is supplied to a recording head 5 by a special recording circuit 4 and recorded on a magnetic recording medium 6. The medium 6 is made up of a plurality of laminated magnetic layers, as will be explained in detail later.
As will be described later, different information is recorded on a plurality of recording tracks in each magnetic layer by a recording means comprising the special recording circuit 4 and recording head 5. Note that this recording medium 6 is transported as indicated by an arrow in the figure by a transport mechanism (not shown). Thus, the information recorded on the recording medium 6 is reproduced and separated and extracted by a reproduction separation means comprising a reproduction head 7 and a special reproduction circuit 8, as will be described later. The reproduction information signal sent from the reproduction circuit 8 is transferred to a signal processing circuit 10 or a comparison circuit 1 by a switching circuit 9.
1 is given. The switching circuit 9 is initially switched to the signal processing circuit 10 side by a switching signal applied to the terminal 12. The reproduced information signal supplied to the signal processing circuit 10 is subjected to processing such as addition or subtraction in accordance with the designated signal applied to the terminal 13 in this circuit, and is then sent to the recording information memory via the OR gate 2. recorded in At this point, the switching circuit 9 is connected to the terminal 12.
It is switched to the comparison circuit 11 side by a switching signal given to the comparison circuit 11 side. Information newly written from the signal processing circuit 10 in the recorded information memory 3 is recorded on the recording medium 6 in the same manner as in the above case. The information recorded again on this recording medium 6 is also reproduced in the same manner as in the above case. This reproduced information signal is then applied to one input terminal of the comparison circuit 11 via the switching circuit 9. The above comparison circuit 11
Since the recorded information signal from the recorded information memory 3 is applied to the other input terminal of the comparator circuit, both information signals are compared, and if they match, this comparator circuit 11 A confirmation information signal is sent from the output end. Since this confirmation information signal is applied to one input terminal of the AND gate 14, the designation signal applied to the other side of the AND gate 14 is supplied to the response mechanism 15 through this AND gate 14. Thus, the response mechanism 15 performs a predetermined operation in response to the designated signal applied to the terminal 13. Now, a specific usage example of the magnetic recording/reproducing apparatus shown in FIG. 1 will be described as follows.

For example, a case where the present invention is applied to an automatic deposit withdrawal device will be explained. To record the deposit amount on the recording medium, use terminal 1.
give numerical information corresponding to the deposit amount. Then, this numerical information is stored in the recording information memory 3 and recorded on the recording medium 6 by the recording circuit 4 and the recording head 5. The numerical information recorded on the recording medium 6 is reproduced by a reproduction head 7 and a reproduction circuit 8 and input to a signal processing circuit 10. However, at this time, since no designation signal is applied to the terminal 13, the signal processing circuit 10 performs no processing. Therefore, numerical information exactly the same as the numerical information given to the terminal 1 is written into the recording information memory 3. This newly written numerical information is recorded on the recording medium 6 again, and then reproduced and given to the comparator circuit 11.
Since the newly written numerical information (=first numerical information) is given to the other input terminal of the comparator circuit 11, a match is naturally achieved, and a confirmation information signal is added to one input terminal of the AND gate 14. . However, since no designation signal is given to the terminal 13, the response mechanism 15 does not operate and no deposit is withdrawn. Now, in order to withdraw a deposit, it is assumed that the recording medium 6 on which the deposit amount is recorded is inserted and a designation signal corresponding to the withdrawal amount is given to the terminal 13.

Then, the numerical information recorded on the recording medium 6 becomes
The signal reproduced by the reproduction head 7 and the reproduction circuit 8 enters the signal processing circuit 10. Now, if the reproduced numerical information signal is a 5-unit signal and the designated signal applied to the terminal 13 is a 3-unit signal, the signal processing circuit 10 performs subtraction to calculate the difference of 2 units. The signal is sent to the recording information memory 3. Thus, the memory 3 stores two units of signals and records them on the recording medium 6. The recorded two units of signal are reproduced and applied to one input terminal of the comparator circuit 11. The other input terminal of the comparison circuit 11 is connected to the memory 3.
Since 2 units of signal stored in are added,
A confirmation information signal is sent from the output end of the comparator 11,
This is applied to one input terminal of AND gate 14. Therefore, the designated signal applied to the other input terminal of the AND gate 14, that is, the signal of three units, is supplied to the response mechanism 15. Thus, the response mechanism 15 automatically withdraws three units of deposit. In this way, this device always compares the recorded information recorded by the recording means and the information reproduced by the reproducing means to check whether the two pieces of information are different, so even if the recording medium 6 is Even if the medium is a manufactured one, it is possible to determine whether or not a legitimate recording medium was used during the recording and reproducing process using special recording means and reproducing means.

Therefore, the configuration of the recording medium 6, the recording means, the reproducing means, etc. will be explained in order below. FIG. 2 is a sectional view of the recording medium 6 explained in FIG. 1. As shown in the figure, this recording medium 6 is constructed by sequentially laminating on a substrate 21 an internal magnetic layer 22 having a coercive force HC2, an intermediate layer 23 made of a non-magnetic material, a surface magnetic layer 24 having a coercive force HCl, and a surface protective layer 25. be done. In addition, regarding the above-mentioned holding force, the materials are selected so that the relationship becomes HCl - HC2. FIG. 3 is a diagram showing a specific example of the recording means explained in FIG. 1.

As shown in this figure, two sets of recording heads 31, 32 and 33, 34 are placed on the first and second recording tracks 3, respectively, with respect to the recording surface of the recording medium 6 that is transported in the direction of the arrow.
5 and 36 are arranged correspondingly. That is, one set of recording heads 31 and 32 are arranged so that they face the first recording tracks 35 and 36, respectively, and the positions of the gaps of both heads 31 and 32 are on a straight line in the width direction of the recording medium 6. is set up. Another set of recording heads 33 and 34 is located at a position a predetermined distance apart from the heads 31 and 32 in the longitudinal direction of the recording medium 6.
Similar to Nos. 1 and 32, they are installed opposite recording tracks 35 and 36. The pair of recording heads 31 and 32 are both magnetic heads for recording signals on the internal magnetic layer 22 of the recording medium 6, and both have a gap G2 wide enough to sufficiently magnetize up to the internal magnetic layer 22. are doing.

Thus, the recording head 31 is supplied with a recording signal B, which is a digital signal, for example, which is applied to a terminal 37, and the recording head 32 is supplied with a signal -B, which is obtained by making the above-mentioned recording signal B reverse polarity by a reverse phase circuit 38. are supplied respectively. On the other hand, the other pair of recording heads 33 and 34 are magnetic heads for recording different signals on the surface magnetic layer 24 of the recording medium 6, and both of them are magnetic heads that are capable of magnetizing only the surface magnetic layer 24. It has a relatively narrow gap width G1 so as to generate a magnetic field, that is, a magnetic field that does not affect the inner magnetic layer 22.

Thus, the recording signal A, which is a digital signal, for example, applied to the terminal 39 is supplied to the recording heads 33 and 34 after being delayed by a predetermined time by the delay circuit 40. The delay circuit 40 causes the recording position on the recording medium 6 by the recording heads 31 and 32 to coincide with the recording position by the recording heads 33 and 34 when the recording signal A is applied simultaneously with the recording signal B. It is provided so that the running speed of the recording medium 6 and the recording heads 31, 32 and 33, 3 can be controlled.
A time delay determined by the distance between the two is performed.
Therefore, when the recording medium 6 travels in the direction of the arrow, the magnetic layer 22 is first applied to the recording medium 6 by the recording heads 31 and 32.
, 24 are recorded.

At this time, the recording signal B is recorded on the first recording track 35, and the reverse polarity recording signal -B is recorded on the second recording track 36, respectively. Then, when this recorded portion passes through the installation location of recording heads 33 and 34, this recording head 3
The signals B and -B respectively recorded on the first recording track 35 and the second recording track 36 of the surface magnetic layer 14 by the signals B and 34 are both rewritten by another recording signal A. As a result, as shown in Figure 4a,
Regarding the surface magnetic layer 24, the signal A is recorded on both the first recording track 35 and the second recording track 36. In other words, the recorded content 35A recorded on the first recording track 35 and the recorded content 36A recorded on the second recorded track 36 are exactly the same in both content and polarity. In addition, as shown in FIG. 3b, the internal magnetic layer 2
2, the signal B is recorded on the first recording track 35, and the signal -B is recorded on the second recording track 36, respectively. In other words, the recorded content 35B recorded on the first recording track 35 and the recorded content 36B recorded on the second recording track 36 have the same content but opposite polarities. In the above description, the case where the signal B is recorded on the first recording track 35 of the internal magnetic layer 22 and the signal -B is recorded on the second recording track 36 is described. The signal -B may be recorded on one recording track 35 and the signal B may be recorded on the second recording track 36. Also, signals A and -A of opposite polarity are recorded on the first and second recording tracks of the surface magnetic layer 24,
The signal B of the same polarity may be recorded on both the first and second recording tracks of the internal magnetic layer 22. Further, when recording the same signal of the same polarity over two tracks as in the surface magnetic layer 24 of the embodiment described above, recording is performed simultaneously using one recording head having a track width corresponding to the width of the recording medium 6. It's okay. Furthermore, the recording heads 31 and 32 for the surface magnetic layer 24 and the recording heads 33 and 34 for the inner magnetic layer 22 may be integrated as shown in FIG. That is, in the one shown in FIG. 5, a gap G1 for recording on the surface magnetic layer 24 and a gap G2 for recording on the internal magnetic layer 22 are attached to a central leg 50 and both sides of this central leg 50. A pair of side legs 51 and 52 are provided. FIG. 6 is a diagram showing a specific example of the reproduction means explained in FIG. 1.

As shown in FIG. 6, reproducing heads 61 and 62, which are provided opposite to the recording surface of the recording medium 6, are arranged side by side so that their gears are on a straight line in the width direction of the recording medium 6. . The reproduction head 61 is a magnetic head for reproducing the signal recorded on the first recording track 35, and the reproduction head 62 is for reproducing the signal recorded on the second recording track 36. It is a magnetic head. Note that the recording heads 33 and 34 for the surface magnetic layer 24 described above can also be used as the reproduction heads 61 and 62. Now, when the recording medium 6 travels as shown by the arrow, the signals B and A recorded in each of the first recording tracks 35 of the internal magnetic layer 22 and the surface magnetic layer 24 of the recording medium 6 are transferred to the reproduction head 61. and are played simultaneously. Further, the signals -B and A recorded in the second recording track 36 of the inner magnetic layer 22 and the surface magnetic layer 24 are simultaneously reproduced by the reproducing head 62. As a result, the following reproduction signals X are sent to the reproduction heads 61 and 62.
and Y are obtained. The reproduced signals X and Y are then supplied to an addition circuit 63 and a subtraction circuit 64, respectively.

The circuits 63 and 64 convert the reproduction signals X and Y into the recording signal A.
, B signals, and the adder circuit 6
3 (X+Y), and in the subtraction circuit 64 (
The calculation (X-Y) is performed. As a result, from the output terminal 65 of the adder circuit 63, a signal 2 having a magnitude twice that of the recording signal A is output.
From the output terminal 66 of the subtraction circuit 64, a signal 2B, which is twice as large as the recording signal B, is separated and taken out. Note that there are some differences in the above arithmetic processing depending on the recording mode of the reverse polarity signal, so these are summarized in the following table. As is clear from the above table, the reproduced signal output after the calculation processing is the first and second recording track 35.
, 36, i.e. 2A or 2B respectively.

These signal magnitudes are obtained when signal A or B is recorded on a normal single-layer recording medium with one magnetic head having the total track width of the first and second recording tracks 35 and 36. It is almost the same size as the reproduced signal, but
In the means of the present invention, one recording surface (first
, the total track width of the second recorded track).
It has an unprecedentedly great effect in that it is possible to efficiently record and reproduce the types of signals A and B in a separable manner. This is a result of effectively utilizing the thickness direction of the recording medium 6. Furthermore, since the two signals A and B can be easily separated by adding and subtracting the reproduced signals X and Y, signal processing is extremely efficient. Furthermore, this method is not only effective for high-density recording and reproduction, but also effective for protecting the confidentiality of recorded signals. That is, if the normal reproducing operation is performed over the first and second tracks, the internal magnetic layer 22,
The signals recorded on the surface magnetic layer 24 interfere with each other in a complicated manner, making it impossible to distinguish between normal signals, and it is also difficult to detect the recording on the inner magnetic layer 22 by means of transfer or the like. After all, since the recording medium has two layers, and the recording surface of one of the layers is divided into two tracks, on which the same signals with mutually different polarities are recorded, the recording means and reproducing means of the present invention It is not possible to obtain a legitimate signal without knowing the reality of the signal. Also, if we pay attention to the surface magnetic layer 24 of Aspects 1 and 2 in the previous table, since the signals of the surface magnetic layer 24 can be recorded and reproduced in the same manner as before, when used in a personal identification card, it is possible to use the conventional personal identification card. If another signal such as a code is recorded in the internal magnetic layer 22, counterfeiting can be made difficult. However, as far as the reproducing means is concerned in the above-mentioned recording and reproducing means, basically the magnetic flux appearing on the surface of the recording medium is detected by a magnetic head and the signal is reproduced, so the above-mentioned two-layer special recording medium is used. Instead, for example, it is not impossible to use a single-layer recording medium and perform recording so that the magnetic flux on its surface appears equivalent to that of a regular two-layer recording medium. Therefore, it is conceivable that a personal identification card may be forged using an unauthorized recording medium, for example, by means of contact transfer, reproduction using a magnetic head, copying by recording, or the like. However, regarding the forged item, the record on this device again,
When reproducing, the recorded information is determined depending on the special characteristics of the recording medium whose thickness dimensions of the magnetic layer and the intermediate layer are specified, and the recording means and reproducing means compatible with this recording medium, as well as their mutual relationships. There is bound to be a discrepancy between the information and the reproduced information, which is different from when a regular recording medium is used. Thus, according to the device of the present invention, which has the configuration shown in FIG. 1 and which compares recorded information and reproduced information to check whether the two pieces of information are different, fraud caused by forgery can be immediately discovered. It is something.

Note that the present invention is not limited to the embodiments described above. For example, in the above embodiment, the recording medium 6 is provided with two magnetic layers, the inner magnetic layer 22 and the surface magnetic layer 24, but the number is not limited to two layers, and three or more magnetic layers may be provided. You can do it like this. Furthermore, the number of recording tracks does not necessarily need to be limited to two; in short, a plurality of tracks may be provided. However, when the number of magnetic layers and the number of tracks is increased to two or more, it is necessary to increase the number of recording heads and reproduction heads, and to change the configuration of the circuit for separating and extracting reproduction information signals. Further, in the above embodiment, the switching circuit 9, the signal processing circuit 10, the and game port 4
, a response mechanism 15, an OR gate 2, etc. have been described, but the point is that it is sufficient that the configuration is such that recorded information and reproduced information are compared in a comparison circuit, and the surrounding circuits can be changed depending on the purpose of use. It may be changed as appropriate. Furthermore, although the above embodiments have been explained on the assumption that the recording current value is always constant, the recording current value may be changed to a range in which normal recording is possible for each layer of magnetic material in a regular recording medium, a range in which normal recording is not possible, etc. It may be possible to select and record.
It goes without saying that various other modifications can be made without departing from the gist of the present invention. As explained above, according to the present invention, different information can be efficiently recorded and read and separated in each magnetic layer of a magnetic recording medium formed by stacking a plurality of magnetic layers. It is possible to provide a magnetic recording/reproducing device that can simultaneously check whether the medium itself is genuine or not.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, FIG. 2 is a sectional view of a magnetic recording medium in the same embodiment,
3 is a diagram showing the recording means in the same embodiment, FIG. 4 is a diagram of the recording pattern of each magnetic layer in the embodiment, FIG. 5 is a perspective view showing a modification of the recording head in the same embodiment, and FIG.
The figure is a diagram showing a reproduction means in the same embodiment. 3...recording information memory, 4...special recording circuit, 5...recording head, 6...magnetic recording medium, 7... Playback head, 8...
・Special reproduction circuit 11... Comparison circuit, 22...
...Inner magnetic layer, 24...Surface magnetic layer, 3
1-34... Recording head, 35, 36...
...First and second recording tracks, 38...Reverse phase circuit, 40...Delay circuit, 50...Central magnetic leg, 51, 52... ...Side legs, 61, 62...
...Regeneration head, 63... Addition circuit, 64
・・・・・・Subtraction circuit.

Claims (1)

[Claims] 1. A magnetic recording medium formed by laminating a plurality of magnetic layers, a recording means for recording different information on each of the plurality of recording tracks in each magnetic layer of the medium, and a recording means for recording different information on each recording track in each magnetic layer of the medium. a means of reproducing each
and means for comparing each piece of information reproduced by the means with the information recorded by the recording means to check whether they are different from each other and to determine whether or not the magnetic recording medium is a regular one. A magnetic recording/reproducing device characterized by: