JPS62150514A - Magnetic recording device - Google Patents

Abstract

PURPOSE:To prevent generation of the crosstalk by displacing other magnetic head from the normal position in applying recording or reproduction of a channel by using one optional head among multi-channel magnetic heads. CONSTITUTION:While a switch 9A is turned on and the channel A is reproduced, an input level of an inverter 27 goes to a low level in an A channel bimorph drive circuit 18A, a voltage impressed to an A channel bimorph plate 12A is zero and the magnetic head 2A is held at a normal position. During this time, the input of an inverter 27 goes to a high level in a B channel bimorph drive circuit 18B, transistors 23, 24 are both turned off and the voltage impressed to the B-channel bimorph plate 12B is expressed as E1B=-E2Bnot equal to 0 and the magnetic head 2B is deviated from the normal position. Conversely, the switch 5B is turned on and the B channel is reproduced, then the magnetic head 2A is deviated from the normal position. Thus, no crosstalk is caused even at time of recording and reproduction.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application> The present invention relates to a magnetic recording device having a multi-channel magnetic head, and is intended to prevent crosstalk.

<Prior art> In a conventional multi-channel magnetic head, the multiple magnetic heads that make up the head are not able to contact the magnetic recording medium independently, and the whole magnetic head is always connected to the magnetic recording medium together. It has a contact structure.

<Problems to be Solved by the Invention> As described above, when a plurality of magnetic heads come into contact with a magnetic recording medium together, crosstalk problems occur for the following reasons.

Now, let us consider a two-channel magnetic recording/reproducing apparatus such as an electronic still camera using a disk-shaped magnetic sheet as shown in FIG. In the figure, 101 is a two-channel magnetic head, which has an A-channel magnetic head 102A and a B-channel magnetic head 102B, and these two magnetic heads 102A and 102B are fixed to a common base 103. . 104 is a magnetic recording medium, 104A is an A channel track, and 104B is a B channel track. 105A is the A channel recording selection switch,
105B is the B channel recording selection switch, 106A
1. Recording amplifier for the channel, 106B is the recording amplifier for the B channel, 107A is the recording/playback switch for the A channel, 107B is the recording/playback switch for the B channel, 108A is the playback amplifier for the A channel,
109A is the A channel playback selection switch, 109B
l: tB channel playback selection switch.

For example, when recording on track 104A of channel A, switch 1 (+5A) is turned on, switches 107A and 107B are both turned on to the recording side (black circle side), and other switches 105B, 109A and 109
B is turned off. As a result, the signal from the input terminal 110 is transmitted to the recording amplifier 106Aii! The signal is supplied to the A-channel magnetic head 102A, and recorded on the track 104A. However, the two magnetic heads 102A, 102
Since there is a slight magnetic coupling between the B channels, magnetic flux leaks from the A channel magnetic head 102A that is about to record to the adjacent B channel magnetic head 102B. In any case, since the magnetic head 102B is also in contact with the magnetic recording medium 104, B
Recording is also performed on the track 104B of the channel. That is, crosstalk occurs.

On the other hand, when reproducing from track 104B of the B channel, for example, switch 109B is turned on, and both switches 107A and 107B are turned to the reproduction side (white circle side). The other switches 105A, 105B and 109A are turned off. As a result, the signal from the B channel magnetic head 102B is amplified by the reproduction amplifier 108B,
It is output to terminal 111. However, since the magnetic head 102A of the A channel is also in contact with the magnetic recording medium 104, the signal of the track 104A of the A channel is induced in this magnetic head 102A, and the resulting magnetic flux is
It leaks from the magnetic head 102A of the channel to the magnetic head 102B of the adjacent B channel. Therefore, the A channel signal, which is not intended for reproduction, mixes into the B channel signal. That is, crosstalk occurs.

It is an object of the present invention to prevent the above-mentioned crosstalk from occurring in a magnetic recording device having a multi-channel ventilation head.

Means for Solving the Problems> A magnetic recording device according to the present invention that achieves the above-mentioned objects includes: (a) a plurality of magnetic heads, a common base for the plurality of magnetic heads, and a base on each of the bases; a multi-channel magnetic head having a plurality of piezoelectric elements each having an end attached thereto and the magnetic head attached to each tip thereof, the plurality of piezoelectric elements holding each magnetic head in a normal position; (b) A drive circuit that applies voltage to a piezoelectric element holding another magnetic head while a certain magnetic head is used for recording or reproduction, and displaces the other magnetic head from its normal position by deforming the piezoelectric element. It is equipped with the following.

Here, the piezoelectric element may be used to displace the magnetic head so that the gap is separated from the magnetic recording medium, or it may be displaced so that the azimuth changes while keeping the gap in contact with the magnetic recording medium. good.

With the above-mentioned configuration, only the desired magnetic head to be used for recording or reproduction can be held at the normal position by the action of the piezoelectric element, and all other magnetic heads can be displaced from their normal positions. can. Since a magnetic head displaced from its normal position has a large spacing loss or azimuth loss, no crosstalk occurs during recording or reproduction.

<Example> The present invention will be described in detail below with reference to FIGS. 1 to 13.

FIG. 1 is a perspective view of a two-channel magnetic head that utilizes spacing loss in an embodiment of the present invention. FIG. 11 is a circuit diagram of an example of a two-channel magnetic recording/reproducing device, and FIGS. 12 and 13 are diagrams illustrating its operation.

First, in FIG. 1, the A channel magnetic head 2A
Bimorph and B channel magnetic heads 2B are attached to a common base 3 by bimorph plates 12A and 12B, respectively.

The two bimorph plates 12A and 12B are fixed to the base 3 so that the two bimorph plates 12A and 12B face each other parallel to each other, have their tips facing the magnetic recording medium 4, and are deformed in a plane perpendicular to the longitudinal direction of the track. has been done. Further, magnetic heads 2A, 2 are provided at the tips of each bimorph plate 12A, 12B.
B is fixed one by one so that the gap faces the magnetic recording medium 4. In FIG. 1, 12A-1, 12A-2 and 12A-3 are lead wires of the bimorph plate 12A,
12B-1, 12B-2 and 12B-3 are lead wires of the pymorph board 12B. Bimorph board 1 of this example
2A and 12B, as illustrated in FIG. 2, are two piezoelectric elements 13, 14 and three electrodes 15, 16, 17 stacked alternately. A piezoelectric element expands or contracts by applying a voltage. Therefore, the bimorph plate 12A in FIG.
(12B) if, f[Depending on how voltage is applied between the electrodes, the shape changes as shown in Figure 3 (al, (bl, (el). Figure 3 (al is E, A=E2A=O( E,
,=E2. =O), same figure (bl is EIA = ”
2A〉0(E18=-E28〉0, the same figure (c) shows E,
Shape examples in the case where A=-E2A<0 (E, , =-E2.<0) are shown.

Here, it is assumed that EIA and E4 are the voltages of one outer Ti electrode 15 with the center common electrode 16 as a reference, and E2A and E2b are the voltages of the common electrode 16 with the other outer electrode 17 as a reference. By selecting the magnitude and polarity of the voltage applied to the bimorph plates 12A and 12B, the two-channel magnetic head 1 shown in FIG. 1 can be configured as shown in FIG. 4(a).
.

(bl, two magnetic heads 2A as shown in (c+).

The position of 2B can be changed freely. However, Fig. 4 (al, bl, (cl) is a front view of the magnetic/\rad viewed from the longitudinal direction of the track.
This is a case where E1A=E2A=0 and E16=E2+5='', and the two magnetic heads 2A, 2B are both at the normal position ``t'' where the gap contacts each track 4A, 4B of A, B of the magnetic recording medium 4. Figure 4 (b)
) is a case where EIA=E2A=0 and E,B=-E2B~0, and only the A channel magnetic head 2A is held at the normal position with respect to the track 4A, and the B channel magnetic head 2B is The gap is slightly separated from track 4B due to the curvature of bimorph plate 12B. Figure 4 f
In case b), when a recording current is applied to the A channel magnetic head 2A to perform recording on the trunk 4A, even if magnetic flux leaks to the B channel magnetic head 2B, there will be no magnetic flux between the magnetic head 2B and the track 4B. Since a large spacing loss has occurred, no recording is performed on track 4B. Also, when the magnetic head 2A of the A channel reproduces the signal from the track 4A as shown in FIG. 4(b), the magnetic head 2B of the B channel does not reproduce the signal of the track 4B due to spacing loss. The signal is A
It does not mix into the output of the magnetic head 2A of the channel. FIG. 4 1cl is E, A=-E2A="w.

In addition, this is the case when E16=E211-0, as shown in FIG. 4(b).
Contrary to the case, only the B channel magnetic head 2B is held at the normal position with respect to the track 4B, and the gap between the A channel magnetic head 2A is the same as the bimorph plate 12A.
It is slightly away from track 4A due to the curvature of. Therefore, when a recording current is applied to the B channel magnetic head 2B to record on the track 4B, a large spacing loss occurs between the A channel magnetic head 2A and the track 4A. Even if the magnetic flux leaks, recording to the l-rack 4A is not performed. Also, when the B channel magnetic head 2B reproduces the signal from track 4B, the A channel magnetic head 2AI does not reproduce the signal from track 4A due to spacing loss, so the signal from track 4A is output from the B channel magnetic head 2B. There is no chance of contamination. Note that if the gap of the magnetic head is separated from the track by 1 μm or more, a sufficient spacing loss can be obtained to prevent crosstalk.

Next, an example using 7-zimas loss will be described with reference to FIGS. 5 and 6. In the two-channel magnetic head 1 of this embodiment, the two bimorph plates 12A and 12B face each other parallel to each other, have their tips oriented parallel to the magnetic recording medium 4, and are deformed in a plane parallel to the magnetic recording medium 4. As shown, each base end portion is fixed to the base 3. Each bimorph plate 12A.

One magnetic head 2A and one magnetic head 2B are fixed to the tip of the magnetic head 12B so that the gap faces the magnetic recording medium 4. Bimorph board 12A.

12B is the one explained with reference to FIGS. 2 and 3. In the two-channel magnetic head 1 shown in FIG. 5, the two-channel magnetic head 1 shown in FIG.
a), (b), (As shown in cl, the positions of the two magnetic heads 2A and 2B can be changed freely. However, in FIG. 6 (al, +b).

(El is a plan view of the magnetic head. FIG. 6 fa) is
This is the case where E, A=E2A=0 and E16=E2a=O, and the two magnetic heads 2A and 2B are both held at regular positions with a predetermined azimuth. In the figure, G indicates a gap. FIG. 6(b) shows the case where E = E = 0 and EIIs = "'21.' MAO, and only the A channel magnetic head 2A is held at the normal azimuth with respect to the track 4A, and the B channel magnetic head 2
In B, the azimuth is deviated from the normal direction due to the curvature of the bimorph plate 12B. Figure 6 (In the case of BL, when recording on track 4A by flowing a recording current to the magnetic head 2A of the A channel, even if magnetic flux leaks to the magnetic head 2B of the B channel, the magnetic head 2B and track 4B Since there is an azimuth difference between the 618th (b
), the A channel magnetic head 2A is used to record track 4.
When reproducing the signal from A, the B channel magnetic head 2
Since B does not reproduce the signal of track 4B due to azimuth loss, the signal of track 4B will not be mixed into the output of the A-channel magnetic head 2A. Figure 6 (el is E
, A=-E2A+o and E, ,=E2. = 0, and in contrast to the case shown in FIG. The azimuth is deviated from the normal direction due to the curvature of 12A. Therefore, when recording or reproducing track 4B with the B channel magnetic head 2B, crosstalk occurs due to the azimuth loss of the A channel magnetic head 2A. do not have.

Next, Fig. 7 shows another example using spacing loss.
This will be explained with reference to FIG. In the two-channel magnetic head 1 of this embodiment, as shown in FIG. 7, there are two bimorph plates 12A.

The base end portion of each magnetic recording medium 12B is fixed to the base 3 so that the magnetic recording medium 12B is deformed in a direction perpendicular to the longitudinal direction of the track and in a plane perpendicular to the magnetic recording medium 4. Each bimorph plate 12
One magnetic head 2A and one 2B are fixed to the tips of the magnetic heads A and 12B so that the gap faces the magnetic recording medium 4. In the two-channel magnetic head 1 shown in FIG. 7, when the bimorph plate 12B, for example, is bent, the gap of the magnetic head 2B is pulled out from the magnetic recording medium 4 as shown in FIG.

Still another example utilizing spacing loss is shown in Fig. 9.
This will be explained with reference to FIG. In the 2-channel magnetic/lid 1 of this embodiment, as shown in FIG. 9, there are two bimorph plates 12A.

The magnetic recording media 12B are arranged horizontally parallel to the magnetic recording medium 4, and their base ends are fixed to the base 3 so as to be deformed along the track longitudinal direction and in a plane perpendicular to the magnetic recording medium 4. One magnetic head 2A, 2B is fixed to the tip of each bimorph plate 12A, 12B with the gap facing the magnetic recording medium 4.

In the two-channel magnetic head 1 shown in FIG. 9, when the bimorph plate 12A, for example, is bent, the gap of the magnetic head 2A separates from the magnetic recording medium 4 as shown in FIG.

Naturally, the control of the bimorph plates 12A and 12B in the two-channel magnetic head 1 of each of the embodiments described above must be performed in synchronization with channel switching in the magnetic recording or reproducing apparatus. A specific example of this will be explained with reference to FIGS. 11 to 13, in which a video signal for one frame is recorded and reproduced in a so-called electronic still camera using a disk-shaped magnetic sheet. In Figure 11,
1 is a 2-channel magnetic head, 2A is an A channel magnetic head, 28IfB channel magnetic head, 5A is a switch for A channel recording selection, 5B is a B channel recording selection switch, 6A is a recording amplifier for A channel, 6B is B Recording amplifier for channel, 7A is recording/playback switch for A channel, 7B is recording/playback switch for B channel, 8A is playback amplifier for A channel, 8B is playback amplifier for B channel, 9A is for A channel playback selection. switch, 9B is a B channel playback selection switch, 10 is a terminal for inputting the signal from the video camera, 11 is an output terminal, 12A1. tA bimorph plate holding the A channel magnetic head 2A, 12B a bimorph plate holding the B channel magnetic head 2B, 18A
Drive circuit for bimorph board 12A for lfA channel, 1
8B is a drive circuit for the B channel bimorph board 12B,
19A is a control switch for the A channel bimorph drive circuit 18A, 19Blf is a control switch for the B channel bimorph drive circuit 18B, 20 is an input terminal for recording command pulses, 21 is an input terminal for recording track switching pulses,
22 is an input terminal for a reproduction track switching pulse.

In the bimorph drive circuit, the emitter of the NPN type transistor 23 and the emitter of the PN1 type transistor 24 are connected and grounded together, and the collector of the transistor 23 is connected to the positive terminal (G) of the DC power supply through the resistor 25.
The collector of the transistor 24 is connected through a resistor 26 to the negative terminal H of the DC power supply. The base of the transistor 23 is supplied with a control pulse 30 which is inverted from the inverter 27 by an inverter 29 . 31 is a pace bias resistance. Furthermore, the common electrode 16 at the center of the bimorph plate is grounded, one of the outer electrodes 15 is connected to the collector of the +- transistor 23 and the sliding terminal of a potentiometer 32 connected to the ground, and the other outer electrode 17
is connected to a sliding terminal of a potentiometer 33 connected between the collector of transistor 24 and ground. The potentiometers 32 and 33 are for voltage adjustment, with a positive voltage applied to one outer electrode 15 and the other outer electrode 17.
A negative voltage is applied to both, but the absolute values of the voltages are made equal.

Next, the operation of the circuit shown in FIG. 11 will be explained with reference to FIGS. 12 and 13. First, in the case of recording, the first
A recording command pulse 34 is inputted as shown in FIG. 2fa), and a track switching pulse 35 is inputted to the input terminal 21 as shown in FIG. 12fb). Pulse 34 is the vertical scan period (IV
), i.e., remains at a high level for a period of 2■, and from this I
After a delay of V, the pulse 35 goes high for a period of IV. These pulses 34.35 are input to the logic operation circuit 36, and the output pulses 37.35 shown in FIG.
38 and two recording track selection switches 5A.

5B is turned on alternately for one period at a time, as shown in tel and (fl) in the figure. Also, while the recording command pulse 34 is high, the two recording/reproduction selector switches 7A and 7B and the two bimorph drives are turned on. Circuit control switch 19A, 19
Both B are input to the recording side (black circle side in FIG. 11) as shown in FIG. 12(g). As a result, while the switch 5A is turned on and the A channel is being recorded, the
In the channel bimorph drive circuit 18A, the input of the inverter 27 becomes low level, both transistors 23 and 24 are turned on, and the voltage applied to the A channel bimorph board 12A is as shown in FIG.
The magnetic head 2A is held at the normal position as shown in FIG. 23, 24
are both turned off, and the B channel bimorph plate 12
The voltage applied to B becomes EI+, -E2B''O, and the magnetic head 2B is shifted from its normal position.

On the other hand, while the switch 5B is turned on and recording of the B channel is performed, the voltage applied to the bimorph plate 12B of the B channel is Ete as shown in FIG.
l''E2.=0, and the magnetic head 2B is held at the normal position, and the voltage applied to the A channel bimorph plate 12A becomes EIA=-E2A'-O, and the magnetic head 2A is held at the normal position. be shifted from

Next, in the case of reproduction, a track switching pulse 39 is input to the input terminal 22 as shown in FIG. 13(a). This pulse 3
9 becomes high level and low level as many times as necessary per 1■ period. This pulse 39 is input to the logic circuit 40,
FIG. 13 (bl, (C1) shows its output pulse 41.4
2, the two playback track selection switches 9A,
9B repeats on/off alternately in 1v periods as shown in the figure (dl, tel).While the track switching pulse 39 for reproduction is applied,
Two recording/playback selector switches 7A, 7B and: control switch 1 for the bimorph drive circuit! Both IA and 19B are input to the reproduction side (E in FIG. 11).

As a result, while the switch 9A is on and the A channel is being reproduced, the input of the inverter 27 is at the 1+- level in the A channel bimorph drive circuit 18A, and the voltage applied to the A channel pymorphono board 12A is is Fig. 13 fgl, (Ill like < E, A
-E=O, and the magnetic head 2A is held at the normal position. During this time, in the B channel bimorph drive circuit 18B, the input of the inverter 27 becomes high level, one transistor 23 and 24 are both turned off, and the voltage applied to the B channel bimorph board 12B is E -1. -0, and the magnetic head 2B is shifted from its normal position. Conversely, while the switch 5B is turned on and the B channel is being reproduced, the voltage applied to the bimorph plate 12B of the 1B channel is as shown in FIG.
p IJ) as <E18=E2. =O, the magnetic head 2B is held at the normal position, and the voltage applied to the A channel bimorph plate 12A becomes E, A=-E2.
A is now 0, and the magnetic head 2A is displaced from its normal position.

Although each of the above embodiments concerns a two-channel magnetic head, a general multi-channel magnetic head may have the same structure as the embodiments. Furthermore, although the above embodiments relate to an electronic still camera using a magnetic disk, it can be used regardless of the shape of the recording medium (tape, sheet, etc.) or the type of recorded or reproduced signal (audio signal, data signal, etc.). ), the present invention can be applied.

<Effects of the Invention> According to the present invention, when recording or reproducing a certain channel using any one of the multi-channel magnetic heads, other magnetic heads can be shifted from their normal positions. , problems such as giving crosstalk to other channels or receiving crosstalk from other channels are eliminated.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a two-channel magnetic head according to an embodiment of the present invention, FIG. 2 is a perspective view of a bimorph plate, FIG. FIG. 9 is an explanatory diagram showing the operation of the two-channel magnetic head shown in FIG. 9 when viewed from the X direction in FIG. FIG. 7 is a perspective view of a two-channel magnetic head according to another embodiment, and FIG. 8 is an explanatory diagram showing its operation as seen from the X direction in FIG. 9. , FIG. 9 is a perspective view of a two-channel magnetic rad according to still another embodiment, FIG. 10 is an explanatory diagram showing its operation as seen from the X direction in FIG. 9, and FIG. 2 according to one embodiment of
FIG. 12 is a timing chart of the operation in recording, FIG. 13 is a timing chart of the operation in reproduction, and FIG. 14 is an explanatory diagram of the prior art. In the drawing, 1 is a two-channel magnetic head, 2A and 2B are individual magnetic heads, 3 is a base, 4 is a magnetic disk, 4A and 4B are trunks, 5A and 581 are switches for switching recording tracks, and 6A and 6B are recording units. Amplifier, 7A and 7B are recording/playback switching switches, 8A and 8B are playback amplifiers, 9A and 9B are playback track switching switches, 10 is a recording signal input terminal, 11 is a playback signal output terminal, 12A and 12B
1 is a bimorph board, 18A and 18B are bimorph drive circuits, 19A and 19B are their control switches, 20 is an input terminal for a recording command, 21 is an input terminal for a recording track switching command, and 22 is an input terminal for a reproduction track switching command. . Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 1Q Figure 12 (k) E□6 − ° “

Claims (1)

[Scope of Claims] A magnetic recording device equipped with a multi-channel magnetic head, comprising a plurality of magnetic heads, a common base for the plurality of magnetic heads, a base end attached to the base, and a tip end of each of the magnetic heads. A multi-channel magnetic head having a plurality of piezoelectric elements to which the above-mentioned magnetic head is attached, the plurality of piezoelectric elements holding each magnetic head in a regular position, and a certain magnetic head used for recording or reproduction. A magnetic recording device comprising: a drive circuit that applies a voltage to a piezoelectric element that holds another magnetic head during the deformation of the other magnetic head, and displaces the other magnetic head from its normal position by deforming the piezoelectric element.