JPS59142729A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To optimize the position and azimuth angle of a magnetic head perpendicular to a track direction on the basis of a position detection signal by adding a function which detects the position of the magnetic head over a recording medium in addition to a function which controls the position of the magnetic head arranged in opposition to the recording medium. CONSTITUTION:Reference tracks t1 and t2 are provided on both side edges of a magnetic tape 5 and reproducing heads S1 and S2 are arranged in opposition to the tracks at distance. A voltage proportional to the phase difference deltaT between playback output signals of the reproducing heads S1 and S2 is added to or subtracted from the amplitude difference (VW-1-VW2) between the playback output signals and voltages are applied to piezoelectric bodies 3a and 3b differentially. Thus, the piezoelectric bodies 3a and 3b are driven to position magnetic heads 4a and 4b. When the magnetic heads 4a and 4b are located at optimum positions, this state is detected as the amplitude difference and phase difference between the playback output signals of the reproducing heads S1 and S2 and the magnetic heads 4a and 4b are held in said state.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magnetic recording/reproducing device, and more particularly to a multi-track tape recorder having track servo and azimuth servo functions of a reproducing head.

<Prior Art> In a magnetic recording and reproducing apparatus that records and reproduces information via a magnetic recording medium, it is necessary to accurately trace recording tracks when reproducing stored information. In particular, when recording and playback are performed by different mechanical systems, such as in a multi-track digital tape recorder, errors tend to occur in the track position accuracy and azimuth in the width direction of the tape, which is a magnetic recording medium. In some cases, maintaining strict accuracy is required. However, when recording and reproducing information using a conventional recording head and reproducing head that are fixedly arranged opposite to the tape running surface, it is difficult to maintain track position accuracy and azimuth angle with high precision.
There are problems with the reliability of information processing.

<Object of the Invention> In view of the above-mentioned problems, the present invention provides a head servo mechanism that performs closed-loop control based on a reference track recorded on a recording medium such as a magnetic tape. The object of the present invention is to provide a new and useful magnetic recording/reproducing device that can control the positioning of corners and the like with high precision.

<Embodiment> FIGS. 1(6), 1(B), and 1(C) are configuration diagrams of main parts of a magnetic recording/reproducing apparatus illustrating an embodiment of the present invention.

In the plan view of FIG. 1(A)b, both ends 1a of the flexible plate 1 formed in a serpentine shape are fixed to the base 2, and the central part is fixed to the base 2.
The book band portion is configured to have flexibility in bending. In addition, the three strips in the center have piezoelectric bodies 3a and 3b attached to their lower surfaces, and the middle strip 1b has a recording head 4a and a reproducing head 4b on its upper surface. Two types of magnetic heads are installed together. Recording head 4
a and the reproducing head 4b are in contact with the recording track of the magnetic tape 5. Note that 6 is a part of a cassette half that accommodates the magnetic tape 5.

When voltages of the same polarity and the same potential are applied to the piezoelectric bodies 3a and 3b, the magnetic heads 4a and 4b are displaced by a displacement amount G in the Z direction (vertical direction) as shown in the front view of FIG. 1(6). That is,
The strip portion of the flexible plate 1 to which the piezoelectric material 3a is attached bends and moves up and down from the open end side opposite to the fixed end, and the strip portion to which the piezoelectric material 3b is attached also moves up and down from the open end side. do. The open ends of the band portions on both sides are in opposite positions, and the middle band portion 1b interconnects these open ends, so that the middle band portion 1b is also moved to the position defined by both open ends. Displace. Therefore, the movement of the magnetic heads 4a and 4b placed on the band member lb is controlled in the Z direction.

If voltages of the same polarity and different potentials are applied to the piezoelectric bodies 3a and 3b, or voltages of different polarities are applied, the amount of deformation will be different between the piezoelectric bodies 8a and 3b, and this will cause the band portion of the flexible plate 1 to In order to make the open end displacement amount different, the middle band portion 1b is displaced while tilting, and the magnetic heads 4a and 4b are moved at an angle θ.
only tilt.

FIGS. 2(A) and 2(B) show the servo reference track recorded on the recording surface of the magnetic tape 5 shown in FIG. 1 and the reproducing head 4b.
FIG. 2 is an explanatory diagram showing a reproduced output waveform from.

・A continuous servo reference track t is formed in a part of the recording surface of the magnetic chip 5, and this reference track t
. A signal section 7 with a constant pitch is recorded. Further, the playback head 4b is moved 81.
Two pieces of S2 are arranged. This playback head S (
! : Each of S2 is a reference track t. The lengths Wl and W2 in the direction perpendicular to the tape running direction in contact with the tape are the amplitudes of the reproduction output vw1. It appears as Vw2. Also, the azimuth angle φ
This deviation appears as a time delay ΔT in the reproduction output between the reproduction heads S1 and 82. Therefore, by detecting the amplitude difference (Vwl''-vW2) and the time delay ΔT of the reproduction output signal, the deviation in the Z direction and the deviation in the azimuth angle φ of the reproduction head 4b can be determined. The delay ΔT is the inclination angle of the signal section 7 within the reference track t with respect to the alignment direction line of the reproducing heads S1 and 82, and W and W2.
Determined by

FIG. 3 is an explanatory diagram showing another embodiment of the servo reference track recorded on the recording surface of the magnetic tape 5 shown in FIG. 1.

In this embodiment, reference tracks 1. , 12 are provided, and correspondingly, the reproducing head 4b is also arranged with S and S2 separated from each other. Determining the deviation in the Z direction and the deviation in the azimuth angle φ based on the amplitude difference and time delay between the reproduction outputs of the reproduction head S and 82 is the same as in FIG. Because of the divided arrangement, the time delay ΔT of the reproduced output appears larger and the accuracy of detecting the deviation of the azimuth angle φ is improved.

Amplitude adjustment time of playback output between playback head S and 82
The positions of the magnetic heads 4a, 4'b are converted to optimal positions by detecting the target delay (phase difference) ΔT and controlling the current supply to the piezoelectric bodies 8a, 8b in response to these detection signals. When the piezoelectric bodies 3a and 8b are energized, the piezoelectric bodies 3a and 3b are bent and deformed as shown in FIG. 4 in accordance with the amount of energization. For example, when a positive potential is applied, the piezoelectric body 3a is deformed into a convex shape under the piezoelectric body 3a, and the flexible plate 1 to which the piezoelectric body 3a is attached is also deformed in the same way. Conversely, when a negative potential is applied, these are bent and deformed in the opposite direction. As explained in FIG. 1, one end of the flexible plate 1 to which the piezoelectric bodies 3a and 3b are attached is a fixed end and the other is an open end, and the open end is actually displaced in the vertical direction. will be done. Therefore, one flexible plate installed at the open end is moved, and the reproducing head S3. S2 is also position-transformed.

FIG. 5 is a block diagram showing one embodiment of the signal processing circuit. The phase difference Δ of the reproduction output signal is added to the amplitude difference ('Wl-VW2') of the reproduction output signal of the reproduction head SI+52.
After adjusting the voltage proportional to T, the voltage is differentially applied to the piezoelectric bodies 8a and 8b. A magnetic head 4a is generated by driving the piezoelectric bodies 3a and 3b.

4b. When the magnetic heads 4a and 4b are placed at the optimal position, this state is the read head S l +82
The amplitude difference and phase difference of the reproduced output are detected, and the magnetic heads 4a and 4b are controlled to maintain this state.

<Effects of the Invention> As explained in detail above, the present invention adds a position control function for a magnetic head disposed facing a recording medium as well as a position detection function for the magnetic head with respect to the recording medium. The head position and the azimuth angle of the magnetic head can be optimally controlled based on the position detection signal. Furthermore, since the position of the magnetic head can be electrically controlled, the operation is easy and the position can be set with high precision. The present invention is particularly effective when recording and reproducing are performed using different mechanical systems, and it is possible to improve the track arrangement density and the recording density in the track running direction, which was not possible with conventional fixed tape guide types.

Although the above embodiment describes the case where a so-called bimorph in which a piezoelectric body and a flexible plate are bonded is used, the present invention is not limited to this. Means can also be used.

[Brief explanation of the drawing]

FIGS. 1(A), 1(B), and 1(C) are main part configuration diagrams of a magnetic recording/reproducing apparatus illustrating an embodiment of the present invention. FIGS. 2A and 2B are explanatory diagrams showing the reference track of the magnetic tape shown in FIG. 1 and the reproduced output signal waveform. FIG. 3 is an explanatory diagram showing another embodiment of the reference track of the magnetic tape shown in FIG. 1. FIG. 4 is an explanatory diagram illustrating the operation of the piezoelectric body. FIG. 5 is a block diagram showing one embodiment of the signal processing circuit. l... Flexible plate, 8a, 8b... Piezoelectric body, 4a...
...Recording head, 4b...Reproducing head, 5...Magnetic tape, 7...Signal section, to...Reference track,
S,, S2... Playback head.

Claims (1)

[Claims] 1. A mounting plate on which an information processing head is mounted is connected to a position conversion system that is displaced in response to an electric signal, and the head position is detected by the information processing head from a position detection track provided on a recording medium. 1. A magnetic recording and reproducing apparatus, characterized in that a detection signal is formed and the position conversion system is operated in accordance with the detection signal.