JPH0782623B2 - Tracking control device for magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to recording / reproducing of information along a plurality of tracks parallel to the running direction of the magnetic tape while sequentially moving the magnetic head in the width direction of the magnetic tape. The present invention relates to a tracking control device in a magnetic recording / reproducing device for performing the above.

[Prior Art] Conventionally, a magnetic recording / reproducing apparatus used as an audio apparatus is usually configured such that the number of tracks is equal to the number of heads, except for those having a rotary head. The above-mentioned number of tracks refers to the total number of data tracks formed in parallel to the tape running direction, and the number of heads is included in a combination head that integrally has a magnetic head such as a recording head, a reproducing head or a recording / reproducing head. Refers to the number of magnetic heads, and so on. The magnetic recording / reproducing apparatus as described above is provided with a tape / head relative position regulating means for regulating the relative position of the magnetic tape and the magnetic head. Most commonly, a guide post having a flange is provided in the tape running path.

However, the tape head relative position regulation means described above
Since the vertical movement of the magnetic tape is prevented by contacting the upper and lower ends of the magnetic tape with the flange, when the magnetic tape with a width wider than the distance between the upper and lower flanges runs, the upper and lower ends of the magnetic tape There is a risk that mechanical stress will be applied to and damage the upper and lower ends. Therefore, in the above-mentioned regulation means, the regulation width of several tens of μm is the limit because damage to the end of the magnetic tape must be avoided. Therefore, in a high-density magnetic recording / reproducing apparatus having an allowable off-track amount of about several tens to several tens of μm, it is not enough to restrict the variation of the magnetic tape by the above flanges.

Further, in recent years, with the development of thin-film magnetic heads, combination heads having a large number of heads have been developed, and the multi-track magnetic recording / reproducing apparatus can have a higher density. With such a device, recording with a narrow track width can be performed, but the allowable off-track amount is accordingly reduced. Therefore, as the tape / head relative position restricting means, in addition to the restricting structure by the above-mentioned flange, a relative position detecting means between the magnetic head and the magnetic tape or track, and a head driving means for moving the magnetic head in the tape width direction. Accordingly, a configuration is adopted in which the magnetic head is controlled following the waving of the magnetic tape.

An example of such a device is a fixed head digital audio tape recorder having the same number of heads and tracks. In the same device, for example, as disclosed in SIK Technical Report EA83-56, SIK Technical Report EA81-64 and Sharp Technical Report 1984-28, servo-dedicated tracks recorded on a magnetic tape are recorded in the tape width direction. The two reproducing heads that are installed side by side are traced, and the reproduction outputs thereof are compared and follow-up control is performed to regulate the relative position between the magnetic head and the magnetic tape.

As another example of the tape head relative position regulation means, in a magnetic recording / reproducing apparatus in which the number of heads and the number of tracks are equal, a tracking signal is recorded at one widthwise end of the magnetic tape, and this is used as a servo reproducing head. Playback with to compare the signal level with the reference level, or record the information for tracking on both widthwise ends of the magnetic tape,
A configuration has been proposed in which these are reproduced by a pair of servo reproducing heads and the signal levels are compared to perform tracking (see Japanese Patent Publication No. 63-64811).

By the way, in the multi-track magnetic recording / reproducing apparatus such as the fixed head digital audio tape recorder,
Since the track pitch was about several hundreds of μm, it was possible to construct a combination head integrated with a recording / reproducing head corresponding to a plurality of tracks of a magnetic tape by adopting a thin film head.

However, in the case of further increasing the recording density, it is possible to narrow the track width by narrowing the gap width of the magnetic head, but there is a limit to the integration of the thin film head. It cannot be made smaller. In addition, increasing the number of heads leads to an increase in the circuit scale, resulting in an increase in cost. Therefore, the track pitch is tens of μm and the number of tracks is tens to
Hundreds of high-density magnetic recording / reproducing devices are difficult to achieve with a configuration having the same number of heads and tracks.

Therefore, in recent years, in a multi-track magnetic recording / reproducing apparatus which is a backup storage device of an information processing system and is generally called a cassette streamer, a recording method called a serpentine method having a number of heads smaller than the number of recording tracks is used. Has been taken.

This serpentine system will be described with reference to FIG. 4. A magnetic tape whose running direction is X and width direction is Y.
It is assumed that 21 has a track group 22 composed of ₁₆ tracks T _{1 to} T ₁₆ formed at an equal pitch a in the Y direction, for example. In this case, a combination head 23 including, for example, four recording heads W _{1 to} W ₄ and four reproducing heads R _{1 to} R ₄ is arranged for the track group 22.

The recording heads W _{1 to} W ₄ have Y pitches of equal pitch b (b = 4a).
The reproducing heads R _{1 to} R ₄ are arranged in parallel with each other in the X direction or the −X direction in pairs with the corresponding recording heads W _{1 to} W ₄ . The pair of recording heads W _{1 to} W ₄ and the reproducing heads R _{1 to} R ₄ are alternately arranged in such a manner that they are interchanged at each arrangement position in the Y direction.

In the recording or reproducing operation, the combination head 23 is first driven to the position shown in FIG. That is,
The centers of the recording head W ₁ and the reproducing head R ₁ coincide with the center of the track T ₁ , and similarly, the centers of the recording head W ₂ and the reproducing head R _{2 and} the center of the track T ₅ , the recording head W ₃ and the reproducing head.
It is a position where the center of R _{3 and} the center of the track T _{9, and} the centers of the recording head W ₄ and the reproducing head R ₄ and the track T ₁₃ coincide with each other.

Next, while recording this relative position, in the case of recording,
The magnetic tape 21 is run in the X direction, and the recording heads W ₁ and W ₃
Are recorded simultaneously on tracks T ₁ and T ₉ .

After recording up to one longitudinal end of the magnetic tape 21,
Next, run the magnetic tape 21 in the -X direction, and
Recording on tracks T ₅ and T ₁₃ simultaneously by W ₂ and W ₄ . Then, after recording to the other end in the longitudinal direction of the magnetic tape 21, the combination head 23 is moved in the −Y direction by the track pitch a, and the centers of the recording head W ₁ and the reproducing head R ₁ are the centers of the tracks T ₂ . Place it to match. Thereafter, while maintaining the relative position, performs recording on the track _{T 2 · T 6 · T 10} · T 14 with one back and forth the magnetic tape 21 in the X and -X directions as above, below, in the same manner Information is recorded on all the tracks T _{1 to} T ₁₆ by a total of 4 reciprocations while moving the combination head 23 by a in the −Y direction each time the magnetic tape 21 reciprocates once.

In the above-mentioned serpentine type multi-track magnetic recording / reproducing apparatus, since a small number of magnetic heads are moved in the tape width direction to perform recording and reproduction on a large number of tracks, the track pitch becomes smaller and the number of tracks increases. However, it is possible to deal with this by moving the magnetic head many times. Therefore, there is no obstacle to the integration of the thin film head.

By the way, as a head / tape relative position regulating means when recording on a magnetic tape by the above-mentioned serpentine system, for example, as disclosed in Japanese Patent Laid-Open No. 62-183019, there is a regulation by the above-mentioned flanges. In addition, a head positioning technique by open loop control using a stepping motor is known.

[Problems to be Solved by the Invention]

However, by adopting the serpentine method, for example, when the track pitch becomes several tens of μm,
Naturally, the track width is several tens of μm, and the allowable off-track amount is about ten to several μm. When this happens,
The above-mentioned tape / head relative position regulating means by open loop control cannot cope with the allowable off-track amount.

If the total stroke of track switching by the serpentine method is about 1 mm and the residual error of tracking in each track switching is about 1 μm, the servo reproducing head requires a large dynamic range of about 60 dB.

However, in the method of tracing the servo track used in the fixed head digital audio tape recorder with two servo heads, the S / N (SN ratio) nominal linearity is guaranteed for such a large dynamic range. Therefore, there is a problem that it is difficult to obtain sufficient tracking accuracy at each track switching position.

[Means for Solving the Problems]

In order to solve the above problems, a tracking control device of a magnetic recording / reproducing apparatus according to the present invention includes a head unit (eg, a head unit) including a predetermined number (one or more) of magnetic heads.
A combination head composed of thin film heads) is sequentially moved in the width direction of the magnetic tape to perform track switching, and recording or reproduction is performed by each magnetic head along a plurality of data tracks parallel to the running direction of the magnetic tape. In the tracking control device in the magnetic recording / reproducing device, a plurality of servo tracks equal to or less than the track switching number are parallel to the data tracks on the magnetic tape.
Also, while the servo signals for tracking are respectively recorded at a pitch that is an integer multiple of the track pitch of the data tracks, a plurality of servo reproducing heads for reproducing the servo tracks respectively have an interval substantially equal to the pitch of the data tracks. And a reproducing portion for servo which is arranged along the width direction of the magnetic tape is integrally provided with the head unit, and further, drive means for moving the head unit in the width direction of the magnetic tape and each track switching position. At the servo track corresponding to the track switching position, the reproducing servo signals from two adjacent servo reproducing heads corresponding to the track switching position are compared with each other, and the head unit is moved by the driving means in the magnetic tape width direction. Characterized by being provided with control means for controlling the quantity A.

When the number of track switching is n, the number of servo tracks is l, and the number of servo reproducing heads is m (n, l, m is an integer), the relationship of n = 1 × (m−1) is satisfied. Is preferred.

[Action]

In the above configuration, for example, when the same number of servo tracks as the number of track switching is provided and two servo reproducing heads are provided, at each track switching position, the servo track corresponding to the track switching position is the above-mentioned two servo tracks. Playback with the servo playback head and compare the playback servo signals,
Tracking is performed by moving the head unit in the width direction of the magnetic tape by the driving means so that the magnetic head is located at the center of the data track for recording or reproducing at the track switching position.

In this case, since tracking at each track switching position is performed based on an individual servo track, tracking at each track switching position in the serpentine system can be accurately performed. In the above, the same number of servo tracks as the number of track switching are provided. Although the case has been described, the number of servo tracks (plurality) smaller than the number of track switching is provided at intervals of an integer multiple of twice the pitch of the data tracks.
The same tracking as above is performed by setting the number of servo reproducing heads to three or more and reproducing each servo track by two or more pairs of servo reproducing heads each including two adjacent servo reproducing heads. You can take action.

[Embodiment 1] The following will describe one embodiment of the present invention with reference to FIG. 1 and FIG.

The magnetic recording / reproducing apparatus according to the present embodiment is used as a backup recording apparatus such as a hard disk drive, and the magnetic heads of which the number is smaller than the number of tracks of the magnetic tape are sequentially moved in the width direction of the magnetic tape. The serpentine system is used for recording and reproducing on tracks.

As shown in FIG. 1 (a), the magnetic recording / reproducing apparatus includes a pair of substrates 2a and 2b that extend in the Y direction, which is the width direction of the magnetic tape 1, and are bonded to each other. The recording heads W1 to W8 and the reproducing heads R1 to R8 (only a part of which are shown) formed as thin film heads constitute a combination head 3 as a head unit.
The combination head 3 is moved in the Y or -Y direction by driving means such as a voice coil type linear motor 17 (see FIG. 2).

As the magnetic tape 1, for example, one having a width of 1/4 inch is used, and each of the magnetic tapes 1 extends in parallel with the running direction (X direction) and has a predetermined track pitch c (for example,
120 μm) 48 data tracks T arranged in Y direction
Information recording / playback is performed along 1 to T48.

One of the above-mentioned substrates 2a has an odd number of recording heads W1 and W2.
-W3, W5, W7 and even-numbered reproduction heads R2, R4, R6, R8 are alternately arranged, and the gap position of each head on the substrate 2a is set on the straight line indicated by the dotted line A.

Also, on the other substrate 2b, odd-numbered read heads R1, R3,
R5 / R7 and even-numbered recording heads W2 / W4 / W6 / W8 are arranged alternately, and the gap position of each head on the substrate 2b is a dotted line B.
It is set on the straight line indicated by.

Corresponding recording heads W1 to W8 and reproducing heads R1 to R8 are arranged side by side in the X direction, which is the running direction of the magnetic tape 1, to form magnetic head pairs H1 to H8. The position of the reproducing head in the X direction is exchanged. Note that the print head W1
.. to W8 and the reproducing heads R1 to R8 are shown to have the same size in the Y direction, but in actuality, the recording width of each recording head W1 to W8 is taken into consideration in consideration of the waving (shake in the width direction) of the magnetic tape 1. Is set to be slightly larger than the reproduction width of each reproduction head R1 to R8.

The distance between the adjacent magnetic head pairs in the Y direction is set to d = 6c (for example, 720 μm), and the combination head 3 is moved 6 times in the Y direction by the track pitch c by the driving means such as the voice coil type linear motor 17. , By switching the track 6 times, all data tracks T1 to T48
Recording or reproduction is performed.

A substrate 7 is provided in a fixed state at a predetermined distance in the X direction from the substrate 2b. A servo signal recording unit 8 is provided near one end of the substrate 7. The servo recording unit 8 is formed by arranging six servo signal recording heads WS1 to WS6 as many as the track switching number "6" in the Y direction, and the widths of the servo signal recording heads WS1 to WS6 in the Y direction and adjacent to each other. The intervals between servo signal recording heads are both data track T1 ~
It is set equal to the pitch c of T48.

Each of the servo signal recording heads WS1 to WS6 has six servo tracks SV1 to SV6 near the end of the magnetic tape 1 in the S direction.
Tracking servo signals are recorded at different frequencies (indicated by hatching for convenience). In that case, the frequencies of the servo signals to be recorded on the respective servo tracks SV1 to SV6 should be set, for example, as shown in Table 1, in particular, so that the difference in frequency between two adjacent servo tracks is sufficiently large. It is set.

A servo reproducing section 5 is provided near one end of the one substrate 2a in the Y direction. The servo reproducing section 5 includes two servo reproducing heads RS1 and RS2 arranged in the Y direction at equal intervals to the track pitch c. The size e of the servo reproducing heads RS1 and RS2 in the Y direction is set to a value slightly smaller than the track pitch c, for example, 100 μm.

The servo reproducing heads RS1 and RS2 are shown in FIG. 1 (a).
At the reference position shown in FIG. 5, that is, at the position where the magnetic head pair H1 faces the data track T1, the lower and upper portions of the servo track SV1 located at the end in the Y direction are covered by substantially the same width, and the servo reproducing heads RS1 and RS2 are used. Servo track
It is positioned so that the amount of reproduced signals from SV1 is equal. The gap between the servo reproducing heads RS1 and RS2 is also set to be located on the straight line indicated by the dotted line A.

As shown in FIG. 2, the servo reproducing heads RS1 and RS2 are connected to a comparator 14 via bandpass filters (BPF) 10 and 11 and amplitude detectors 12 and 13, respectively. above
The BPFs 10 and 11 have passage characteristics for each servo track SV1 to SV6 so that only the vicinity of the frequency of the servo signal recorded on the servo tracks SV1 to SV6 to be reproduced by the servo reproducing heads RS1 and RS2 is passed. Will be changed,
Or, the servo track for each servo track SV1 to SV6
Band pass filters 10 and 11 corresponding to SV1 to SV6 are selectively used.

The output of the comparator 14 is connected to the servo controller 15, and the output of the servo controller 15 is connected to the voice coil type linear motor 17 via the motor driver 16. The voice coil type linear motor 17 drives the servo reproducing section 5 and the combination head 3 integrated with the reproducing section 5 in the Y or -Y direction. The BPFs 10/11, the amplitude detectors 12/13, the comparator 14 and the servo controller 15, especially the servo controller 15 constitutes a control means, and the motor driver 16 and the voice coil type linear motor 17, especially,
The voice coil type linear motor 17 constitutes a driving means.

Further, although not shown, a flange member for suppressing the waving of the magnetic tape 1 in the Y direction to, for example, about ± 20 μm can be provided by regulating both widthwise end portions of the magnetic tape 1.

In the above configuration, when recording on the magnetic tape 1, first, the magnetic tape 1 is run in the X direction, and the servo signal recording heads WS1 to WS6 are used to drive the servo tracks SV1 to SV.
While recording servo signals at the frequencies shown in Table 1 on X6, or after recording, the number of odd-numbered recording heads
W1 ・ W3 ・ W5 ・ W7 for every 12 data tracks T1 ・ T1
Record information on 3 ・ T25 ・ T37. At this time, the odd-numbered reproducing heads R1, R3, R5, and R7 are used to immediately reproduce the recorded information to check if there is any error in recording, and if there is an error, record again. I do.

At this time, the servo signals of the servo track SV1 located at the end in the Y direction are reproduced by the two servo reproducing heads RS1 and RS2, and only the vicinity of 100 KHz which is the frequency of the servo signal of the servo track SV1 is passed. Bandpass filter
The comparator 14 compares the amplitudes of the reproduced signals of the servo reproducing heads RS1 and RS2 with each other through the 10 and 11 and the amplitude detectors 12 and 13. Then, based on the output of the comparator 14, the servo controller 15 drives the voice coil type linear motor 17 via the motor driver 16 so that the amplitudes of the reproduction signals RS1 and RS25 for both servos are equal to each other, and the combination is performed. The head 3 is moved in the Y or -Y direction so that the odd-numbered recording heads W1, W3, W5, and W7 correspond to the corresponding data tracks T1.
-Tracking will follow T13 / T25 / T37.

When recording is completed along the data tracks T1, T13, T25, T37 up to the end in the X direction, this time, while moving the magnetic tape 1 in the -X direction, even-numbered recording heads W2, W4, W6
・ Data track T1, T13, T25 recorded on the outward path by W8
-Recording is performed on 12 data tracks T7, T19, T31, and T43 that are offset by 6 tracks from T37, and at this time, there is no error in the recorded information by the even-numbered reproducing heads R2, R4, R6, and R8. Check immediately whether or not. At this time as well, the servo reproducing heads RS1 and RS2 reproduce the servo signal of the servo track SV1 to perform tracking in the same manner as above. In addition, each servo track SV1 to SV including servo track SV1
Since the recording of the servo signal to 6 is performed on the outward path,
It is not necessary thereafter.

When recording is completed up to the end portion in the −X direction, the combination head 3 is moved by the track pitch c in the −Y direction by the voice coil type linear motor 17 as shown in FIG. While running in the direction
Information is recorded on the data tracks T2, T14, T26, T38 by the odd-numbered recording heads W1, W3, W5, W7. At this time,
The servo playback heads RS2 and RS3 reproduce the servo signal of the servo track SV2, which is shifted in the Y direction by one from the first round trip.
Tracking is performed by moving the combination head 3 in the Y or -Y direction by the voice coil type linear motor 14 so that the reproduction signals of the servo reproducing heads RS2 and RS3 become equal to each other. At this time, the bandpass filters 10 and 11 are set to have a characteristic of passing only around 10 KHz which is the frequency of the servo signal of the servo track SV2.
Alternatively, the BPF10 / 11 provided exclusively for the servo track SV2 is used.

When recording is completed up to the end in the X direction, this time the magnetic tape 1 is moved in the -X direction and the servo reproducing heads RS2 and RS3 are moved.
While performing tracking based on the output of the data track T8, the even numbered recording heads W2, W4, W6, W8
Record on T20 / T32 / T44, and at this time also servo track S
Track with V2.

Thereafter, in the same manner, each time the magnetic tape 1 reciprocates, the combination head 3 is moved by the track pitch c in the -Y direction, and the servo tracks to be used are sequentially moved one by one.
While changing to each one in the −Y direction, by combining the recording heads W1 to W8 and the data tracks T1 to T48 as shown in Table 2, a total of 6 times of track switching is performed, and information is recorded on all the data tracks T1 to T48. Record. At each track switching position, the bandpass filters 10 and 11 pass near the frequency of the servo signal recorded on each servo track SV1 to SV6. Switch to the desired characteristics, or change to each servo track SV1 to SV6
Selectively use the dedicated BPF10 / 11.

Also during reproduction, as in the case of recording, the combination head 3 is moved in the -Y direction by the track pitch c each time the magnetic tape 1 reciprocates, and the servo tracks to be used are sequentially arranged in the -Y direction. The information of each data track T1 to T48 is sequentially reproduced while changing to.

In this embodiment, the same number of servo tracks SV1 to SV6 as the track switching number "6" are provided, and tracking is performed based on the servo signals of the corresponding servo tracks SV1 to SV6 at each track switching position. Accurate tracking can be performed in the serpentine system.

Also, the combination head 3 and the servo reproducing head
Since the thin film heads are used as RS1 and RS2, the dimensional accuracy of each head is improved, and thus the track switching accuracy can be improved.

In the above embodiment, the servo signal recording head WS for recording servo signals on the servo tracks SV1 to SV6 is used.
Although 1 to SW6 are provided, if the servo signals are previously recorded on the servo tracks SV1 to SV6 when the magnetic tape 1 is manufactured, the servo signal recording heads WS1 to SW6 are unnecessary.

Further, in the above embodiment, the number of track switching is set to "6", but the number of track switching can be arbitrarily set to other than "6". In that case, if the number of servo tracks is changed according to the number of track switching. good.

Second Embodiment Next, a second embodiment will be described based on FIG.

In the second embodiment, the number of track switching is set to "6" as in the first embodiment, while the three servo signal recording heads WS1 to WS3 are provided in the servo signal recording unit 8 at the track pitches of the data tracks T1 to T48. They are provided at a pitch twice as large as c (for example, a pitch of 240 μm). On the other hand, the servo reproducing section 5 is provided with three servo reproducing heads RS1 to RS3 for reproducing the servo tracks SV1 to SV3, respectively, at a pitch equal to the track pitch c of the data tracks T1 to T48 (for example, 120 μm), When the head pair H1 faces the data track T1, the two servo reproducing heads RS1 and RS2 are moved to the servo track SV.
It is positioned so as to cover the lower portion and the upper portion in FIG. The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the above-mentioned configuration, the recording procedure by the serpentine method is the same as that in the first embodiment. Therefore, here, only the tracking procedure will be described.
At the track switching position where the recording head W1 and the reproducing head R1 are opposed to the data track T1, the servo reproducing heads RS1 and RS2 reproduce the servo signal of the servo track SV1 and compare the reproducing signals of the both to perform tracking. To do.

Next, the second round trip, that is, the recording head W1 and the reproducing head
At the track switching position where R1 faces the data track T2, as shown in FIG. 3 (b), the servo reproducing head is used.
Tracking is performed by reproducing the servo track SV1 with RS2 and RS3 and comparing the reproduced signals of both.

As shown in Table 3, the servo tracks and the servo reproducing heads to be sequentially used are switched at the third reciprocal shift, and tracking is performed at each track switching position.

〔The invention's effect〕

As described above, the tracking control device of the magnetic recording / reproducing apparatus according to the present invention has a plurality of servo tracks, which are equal to or less than the track switching number, on the magnetic tape in parallel with the data track, and is an integral multiple of the track pitch of the data track. While the servo signals for tracking are recorded at the pitches of, the plurality of servo reproducing heads for reproducing the servo tracks are arranged along the width direction of the magnetic tape at intervals substantially equal to the pitch of the data tracks. A servo reproducing section formed integrally with the head unit, further comprising drive means for moving the head unit in the width direction of the magnetic tape, and a servo track corresponding to the track switching position at each track switching position. Adjacent two servo reproducing heads corresponding to their track switching positions Comparing the reproduced servo signal together with a configuration in which a control means for controlling the movement of the magnetic tape width direction of the head unit is provided by the drive means.

In the above configuration, for example, when the same number of servo tracks as the number of track switching is provided and two servo reproducing heads are provided, at each track switching position, the servo track corresponding to the track switching position is the above-mentioned two servo tracks. Playback with the servo playback head and compare the playback servo signals,
Tracking is performed by moving the head unit in the width direction of the magnetic tape by the driving means so that the magnetic head is located at the center of the data track for recording or reproducing at the track switching position. In this case, since tracking at each track switching position is performed based on a separate servo track, it is possible to accurately perform tracking at each track switching position in the serpentine system.

Although the case where the same number of servo tracks as the number of track switching is provided has been described above, the number of servo tracks (plurality) smaller than the number of track switching is provided at intervals of an integral multiple of twice the pitch of the data tracks. ,
The number of servo reproducing heads is three or more, and each servo track is reproduced by two or more pairs of servo reproducing heads, each pair including two adjacent servo reproducing heads. It is something that can be operated.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1A is a schematic front view of the tracking control device. FIG. 6B is a schematic front view showing the track switching operation. FIG. 2 is a block diagram showing a part of the tracking control device. FIG. 3 is a schematic front view showing the tracking control device of the second embodiment. FIG. 4 is a schematic front view showing a magnetic recording / reproducing apparatus adopting the serpentine system. 3 is a combination head (head unit), 5 is a reproducing section for servo, 15 is a servo controller (control means), 17 is a voice coil type linear motor (driving means),
SV1 to SV6 are servo tracks, RS1 to RS3 are servo reproducing heads, T1 to T48 are data tracks, and H1 to H8 are magnetic head pairs.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-260218 (JP, A) JP-A-2-260216 (JP, A) JP-A-2-260217 (JP, A)

Claims (1)

[Claims] 1. A head unit provided with a predetermined number of magnetic heads is sequentially moved in the width direction of a magnetic tape to perform track switching, and each magnetic head runs along a plurality of data tracks parallel to the running direction of the magnetic tape. In a tracking control device in a magnetic recording / reproducing device adapted to perform recording or reproducing by a plurality of servo tracks, a plurality of servo tracks whose number is equal to or less than the track switching number are parallel to the data track on the magnetic tape, and are substantially integral multiples of the pitch of the data track. While the servo signals for tracking are recorded at the pitches of, the plurality of servo reproducing heads for reproducing the servo tracks are arranged along the width direction of the magnetic tape at intervals substantially equal to the pitch of the data tracks. The servo reproducing section is provided integrally with the head unit, Further, driving means for moving the head unit in the width direction of the magnetic tape, and two adjacent servo reproducing heads corresponding to the track switching position from the servo track corresponding to the track switching position at each track switching position. And a control means for controlling the amount of movement of the head unit in the width direction of the magnetic tape by the driving means by comparing the reproduction servo signals by the tracking control apparatus of the magnetic recording / reproducing apparatus.