JPH0546961A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the tracking accuracy of a serpentine recording and reproducing system by arranging a plurality of servo signal recording and reproducing head pairs on a combination head at prescribed intervals. CONSTITUTION:Servo signal recording and reproducing head pairs S1a-S1b to S4a-S4b are arranged zigzag on a combination head 3 at every track pitch (a). At the time of reproducing servo tracks ST1 and ST2 with the head pair S1a-S1b, the head S1a is used for dynamic tracking when the displacement of a magnetic tape 1 is in the +Y direction or the other head S1b is used when the displacement is in the -Y direction. Therefore, the heads can be used for dynamic tracking irrespective of the position of the tape 1, because a maximum tape displacement margin of a little smaller than 1.5a can be secured in both (+) and (-) directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to improvement of a magnetic recording / reproducing apparatus suitable for a serpentine recording / reproducing system.

[0002]

2. Description of the Related Art Various techniques have been developed as a mainstream technique for promoting high recording density and high transfer rate in a magnetic recording / reproducing apparatus for the purpose of increasing the recording density on the surface of a magnetic tape. .. The areal recording density is generally a linear recording density (BPI: number of bits per inch), which is a recording density in a length direction in which a magnetic tape moves, and a recording track, which is a recording density in a width direction orthogonal to the length direction. Density (TP
I: number of tracks per inch).

Except for those equipped with a rotary magnetic head such as a VTR or DAT, if only the track density is taken into consideration, a magnetic recording / reproducing apparatus equipped with a fixed magnetic head will be described. Generally, the number of tracks recorded on a tape is equal to the number of magnetic heads. In order to increase the track density, a method of increasing the number of tracks per unit width of the tape by narrowing the track width is adopted. Here, the number of tracks refers to the total number of data tracks (also referred to as information tracks) formed in parallel along the tape running direction. Further, the number of magnetic heads means the number of pairs of recording heads and reproducing heads included in one combination magnetic head, or the number of recording / reproducing shared heads.

For convenience of description, the number of tracks per unit width is expressed by the size of the track pitch. In the prior art, a bulk type in which a magnetic material such as ferrite is machined to form a head structure. In the head, the track pitch of about several hundred μm was the limit. On the other hand, there is a possibility that a track pitch of several tens of μm to hundreds of tens of μm can be realized by using a thin film magnetic head which has been remarkably developed in recent years. There is an example.

Although it is possible to increase the number of tracks by using the thin film head as described above, there is a problem that the scale of the track information parallel processing circuit becomes large. Further, it is possible to sequentially switch the tracks to be processed in order to limit the scale of the track information parallel processing circuit. In this case, however, a separate track information processing switching circuit is required, and the required circuit scale is There is an unavoidable tendency to increase.

In view of the above problems, a magnetic recording / reproducing apparatus for multi-track storage represented by a backup storage device of an information processing system employs a serpentine recording / reproducing system. In this method, the number of heads is smaller than the number of tracks on the tape (it is necessary to switch the relative positions of the tracks and heads sequentially), and when processing a data signal, read immediately after writing to ensure reliability. In order to further shorten the processing time, recording / reproducing is performed in the reciprocation of the tape.

Referring to FIG. 6, serpentine recording / reproducing
The method will be briefly described. In this figure, the tape runs
The direction is indicated by X and the width direction is indicated by Y. tape
1 is 16 formed at an equal pitch in the Y direction, for example.
Book truck T₁~ T₁₆With a group of tracks 2 consisting of
There is. Then, for track group 2, for example, four
Recording head W₁~ W_FourAnd 4 playback heads R₁~ R
_FourThe combination head 3 provided with is applied. Record
Recording head W₁~ W_FourWith the same pitch b = 4a in the Y direction
It is provided and the reproducing head R₁~ R_FourIs the corresponding record
Head W₁~ W _FourPaired with + X direction or -X direction
It is provided in. That is, the recording head and the reproducing head
Odd-numbered pair W of₁-R₁And W₃-R₃
In, the recording head is located to the left of the playback head,
On the other hand, even-numbered pairs W₂-R₂And W_Four-R_Foursmell
For example, the recording head is arranged on the right side of the reproducing head.

When recording or reproducing, a combinator
The head 3 is first driven to the position shown in FIG. You
That is, recording head W₁And playback head R₁The center of
Truck T₁Coincides with the center of the recording head W₂
And playback head R₂Center and track T_FiveCenter of
Recording head W₃And playback head R₃Center and track T
₉Center of the head and the recording head W_FourAnd playback head R
_FourCenter and track T ₁₃So that the centers of each match
It is in a state. Relative between such tape and magnetic head
Tape 1 in the + X direction while maintaining the target position,
In case of recording, recording head W₁And W₃By truck
T₁And T₉To record at the same time.

In this case, whether the data was recorded correctly
Track T to determine if ₁In the record
Head W₁Immediately after the data is recorded by
De R ₁To reproduce the data by reading immediately after writing and
Check the quality. At the same time, track T₉At
Is the recording head W₃And the playhead R₃Similar confirmation using
Do. In the unlikely event of a truck T₁Or T₉At
If recording failure occurs, tape 1 to the front of the defective point.
Rewind the recording head W₁Or W₃By the data
Recording is performed by rewriting. Read immediately after such writing
And the rewriting operation is the same for all tracks.
Is.

When the recording is completed up to the end portion of the tape 1 in the -X direction, the tape 1 is then moved in the -X direction and the recording heads W ₂ and W ₄ simultaneously record on the tracks T ₅ and T ₁₃ . Then, after the recording is completed up to the end of the tape 1 in the + X direction, the combination head 3 is moved in the -Y direction by a distance corresponding to the track pitch a, and the centers of the recording head W ₁ and the reproducing head R ₁ are at the track T _1. Place it so that it coincides with the center of ₂ . After that, while keeping the relative position between the tape and the magnetic head, the tape 1
+1 while reciprocating in the X direction and the -X direction, the track T _2, T _6, T ₁₀ and T ₁₄ performs recording. Similarly, while moving the combination head 3 in the -Y direction by the pitch a each time the tape 1 reciprocates once,
Information is recorded on all the tracks T _{1 to} T ₁₆ by a total of four round trips.

In the recording / reproducing apparatus for recording on a large number of tracks by the serpentine recording / reproducing system as described above, a large number of combination heads including pairs of recording heads and reproducing heads smaller than the number of tracks are moved in the width direction of the tape. Since recording and reproduction are performed on the tracks, even when the track pitch is reduced and the number of tracks is increased, it is possible to cope with the increase by increasing the number of times the combination head is moved. An example of such a prior art is disclosed in, for example, JP-A-62-1573.
Japanese Patent Laid-Open No. 05-2005 discloses a positioning technique based on open loop control using a stepping motor as an actuator in the movement of the combination head in the tape width direction. Also, JP-A-62-1830
Japanese Patent Laid-Open No. 18 and Japanese Patent Laid-Open No. 62-183019 disclose the head positioning technique of open loop control using a stepping motor in more detail. More specifically, the head reference position can be determined with a simple configuration. The positioning mechanism that can be determined and its adjustment method are reported.

On the other hand, the magnetic recording / reproducing apparatus of the serpentine recording / reproducing system as described above is provided with a tape position regulating means for regulating the variation of the relative position of the tape with respect to the magnetic head, and its constitution is the width direction of the tape. In general, a guide post having a pair of flanges for guiding both ends of the tape is provided in the running path of the tape.
However, in such a tape position regulating means, mechanical stress is applied to both side ends of the tape width, which may damage the both side ends. Therefore, because it is necessary to avoid damage to both side edges of the tape, several tens of μm
In the high-density recording / reproducing apparatus in which the regulation accuracy of fluctuations is limited, and the allowable off-track amount is limited to about a dozen μm to a few tens of μm, the tape meandering regulation by the flanges is not sufficient. .. Further, in a magnetic recording / reproducing apparatus for multi-track recording, which is equipped with a combination head including a large number of thin-film magnetic heads, it is possible to record with a narrow track width, but the permissible off-track amount also decreases accordingly.

From the above, in addition to the above-mentioned regulation structure by the flange, the relative position detecting means for the tape and the head is moved in the tape width direction and the relative position detecting means for the head and the tape or the head and the track. The head driving means is used to control the head so that the head follows the meandering (also called waving) in the width direction of the tape. As an example of such a technique, there is a digital audio tape recorder which employs a fixed head including a number of magnetic heads equal to the number of tracks. In such a device, for example, Technical Report EA83-56, pp. 51-58, IEICE Technical Report EA81
-64, pp. 33-38, and Sharp Technical Report 198
4, 28, pp. As disclosed in 12-13, two servo-dedicated tracks recorded on the tape are traced by two reproducing heads arranged side by side in the tape width direction, and their reproduction outputs are compared to perform follow-up control. By doing so, the relative position between the head and the tape is regulated.

As another example of the relative position regulating means for the tape and the head, in a magnetic recording / reproducing apparatus in which the number of magnetic heads and the number of tracks are equal, a tracking signal is recorded at one end in the tape width direction, Is reproduced by a servo reproducing head and the signal level is compared with a reference level, or tracking information is recorded at both end portions in the width direction of the tape, and these signals are reproduced by a pair of servo reproducing heads. A configuration has been proposed in which tracking is performed by comparing levels (Japanese Patent Publication No. 63-648).
No. 11). However, if an attempt is made to increase the track density (TPI), the number of magnetic heads increases, and the track information parallel processing circuit scale increases or a track information processing switching circuit is required, and the circuit scale cannot be increased. There wasn't.

[0015]

As described above, the magnetic recording / reproducing apparatus of the serpentine recording / reproducing system is suitable for high recording density and high-speed processing, but in order to further increase the recording density, the recording track width must be increased. With the miniaturization, it is necessary to improve the tracking accuracy of the magnetic head.

Therefore, an object of the present invention is to provide a magnetic recording / reproducing apparatus capable of higher recording density and high-speed processing by improving the tracking accuracy in the serpentine recording type magnetic recording / reproducing apparatus.

[0017]

A magnetic recording / reproducing apparatus according to an aspect of the present invention adapted to a serpentine recording / reproducing system has a plurality of recording and reproducing information on a plurality of information tracks on a magnetic tape. A combination magnetic head including a plurality of information recording gaps and a plurality of servo magnetic gaps for recording and reproducing servo signals on one or more servo tracks, and a combination of the information tracks and the information magnetic gaps. In order to change the combination magnetic head, an actuator for relatively displacing the combination magnetic head in the width direction of the tape is provided, and a plurality of servo magnetic gaps are provided regardless of how the combination of the information track and the information magnetic gap is changed. , So that at least one traces at least part of one of the servo tracks The actuator means is disposed in the combination magnetic head, and further includes position deviation detecting means for detecting a position deviation between the information track and the information magnetic gap based on the servo signal reproduced by the servo magnetic gap. It is characterized in that it also works to control the relative position between the combination magnetic head and the width direction of the magnetic tape so as to minimize the amount of positional deviation detected by the positional deviation detecting means.

A magnetic recording / reproducing apparatus according to another aspect of the present invention adapted to a serpentine recording / reproducing system has a plurality of information recording gaps for recording and reproducing information on a plurality of information tracks on a magnetic tape. And a combination magnetic head including a plurality of servo signal reproducing magnetic gaps for reproducing servo signals on one or more servo tracks, and one or more servo signal recording magnetic gaps for recording servo signals on the servo tracks. A plurality of servo signal reproducing magnetic gaps, and a fixed magnetic head including a plurality of servo signal reproducing magnetic gaps, and an actuator for relatively displacing the combination magnetic head in the width direction of the tape to change the combination of the information track and the information magnetic gap. What is the combination of the information track and the magnetic gap for information? Be changed, they are arranged in a combination magnetic head as at least one tracing at least a portion of one of the servo tracks,
Further, a position deviation detecting means for detecting a position deviation between the information track and the information magnetic gap based on the servo signal reproduced by the servo signal reproducing magnetic gap is provided, and the actuator means is detected by the position deviation detecting means. It is characterized in that it also works to control the relative position between the combination magnetic head and the width direction of the magnetic tape so as to minimize the amount of positional deviation.

[0019]

In the magnetic recording / reproducing apparatus according to the present invention, no matter how the combination of the information track and the information magnetic gap is changed, at least one servo magnetic gap traces at least a part of the servo track. Since it is arranged in the combination magnetic head, the actuator can work to minimize the amount of positional deviation detected by the positional deviation detecting means in any combination of the information track and the information magnetic gap. it can. Therefore, by improving the tracking accuracy, it is possible to provide a magnetic recording / reproducing apparatus of the serpentine recording / reproducing system with improved recording density and processing speed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail with reference to FIGS. In the first embodiment, a magnetic recording / reproducing apparatus adapted to the serpentine recording / reproducing system is shown. In this device, the number of information heads is smaller than the number of information (also referred to as data) tracks on the tape, and information is recorded / reproduced by reciprocating the tape while sequentially switching the combination of information tracks and information heads.

As shown in FIG. 1, the magnet of the present embodiment is
The magnetic recording / reproducing apparatus extends in the Y direction, which is the width direction of the tape 1.
A pair of substrates 3a and 3b that are spread and attached to each other
I have it. A thin film head is formed on these substrates 3a and 3b.
Formed data signal recording head W₁~ W_Four， Day
Signal playback head R₁~ R_Four, And servo signal recording
By the raw head pairs S1a to S4a and S1b to S4b,
Combination head 3 as a head unit
Is made. The combination head 3 is shown in FIG.
By means of the head moving actuator 8 shown in FIG.
Can be moved in the + Y direction or the −Y direction. tape
1 may have a width of 3.8 mm, for example.
It This tape 1 has a flat surface in the running direction (X direction).
The rows extend in rows and are arranged at a predetermined track pitch a in the Y direction.
16 data tracks DT ₁~ DT₁₆along,
Data signals are recorded and reproduced. Furthermore, in the Y direction
Data track DT₁~ DT₁₆Two on both sides of
Servo tracks ST1 and ST2 are arranged. this
The servo tracks ST1 and ST2 are the outermost data.
Tatrac DT₁, DT₁₆From each pitch 2a
They are placed away from each other for recording and reproducing servo signals.
Used for.

In the combination head 3, the odd numbered data signal recording heads W ₁ and W ₃ and the even numbered data signal reproducing heads R ₂ and R are provided on one substrate 3a.
₄ and odd-numbered servo signal recording / reproducing head pair S1
a, S1b, S3a, and S3b are arranged, and the magnetic gap position of each head on the substrate 3a is set on the straight line 3c at the center on the substrate 3a. In the on the other substrate 3b, the even-numbered data signal recording head W _2, W ₄ and the odd-numbered data signal reproducing heads R _1, R ₃ and even-numbered servo signal reproducing heads S2a, S2b, S4
a and S4b are arranged, and the magnetic gap position of each head on the substrate 3b is set on the central straight line 3b.

A data signal recording head W ₁ and a data signal reproducing head R ₁ for tracing the same track, and W
₂ and R ₂ , W ₃ and R ₃ , and W ₄ and R ₄ are arranged side by side in the X direction, which is the running direction of the tape 1, and the first to fourth head pairs for recording / reproducing the data signal are arranged. I am configuring. The positions of the recording heads and the reproducing heads in the odd-numbered head pairs are opposite to those in the even-numbered head pairs. The width of the Y direction of the data signal recording head W ₁ to _W-4, considering the like of the way Bing tape 1, the data signal reproducing heads R ₁ to R ₄
It is set to be slightly larger than the width of. The distance between the pair of data signal recording / reproducing heads in the Y direction is set to b = 4a, and the combination moving head 3 is moved four times in the Y direction by the distance a corresponding to the track pitch by the head moving actuator 8. All the tracks DT _{1 to} DT
_{At 16} , data signals are recorded or reproduced.

Next, the odd-numbered servo signal recording / reproducing heads S1a and S1b and S3a and S3b arranged on one substrate 3a are paired with each other. In the positional relationship in the Y direction, there is a center of servo signal reproducing heads S3a to the fourth position away in the -Y direction by a distance 2.5a from the center of the data signal reproducing heads R ₄ in. Further, a servo signal recording / reproducing head S is provided at a lower position separated by a distance 2a
There is a center of 1a. The upper position apart first 1.5a from the center of the data signal recording head W ₁ in the + Y direction is the center of the servo signal reproducing heads S 1 b. Further, a servo signal recording / reproducing head S3b is provided upwardly at a distance 2a.
The center of is set to be located. The other substrate 3
Even-numbered servo signal recording / reproducing heads S2a and S2b and S4a and S4b arranged on b are also paired. In the positional relationship in the Y direction, the distance from the center of the fourth data signal recording head W _{4 in} the −Y direction is 1.5a.
The center of the servo signal recording head S4a is located at a lower position spaced apart by. Further, the center of the servo signal recording / reproducing head S2a is located below the distance 2a. An upper position at a distance 2.5a from the first center of the data signal reproducing heads R ₁ in the + Y direction is the center of the servo signal write head S2b. Further, the center of the servo signal recording / reproducing head S4b is set to be located above the distance 2a.

That is, the servo signal recording / reproducing head pair S2a forming a second pair above the first pair of servo signal recording / reproducing head pairs S1a-S1b in the + Y direction by a distance a (= data track pitch). -S2b is arranged. Similarly, a servo signal recording / reproducing head pair S3a-S3b forming a third pair is arranged further above the distance a, and a servo signal recording / reproducing head pair S4a- forming a fourth pair is further located above the distance a. S4b is arranged.

Regarding the X direction, as described above, odd-numbered servo signal recording / reproducing head pairs S1a-S1b, S3a.
The center of -S3b is on the straight line 3c, and the even-numbered servo signal recording / reproducing head pairs S2a-S2b, S4a-S4b.
Is located on the straight line 3d. Therefore, when the X and Y directions are aligned, the servo signal recording / reproducing head pairs are arranged in a staggered pattern at each track pitch a as shown in FIG.

The layout of such a servo signal recording / reproducing head pair has the following advantages.

First, in order to increase the amount of recordable information in the tape width direction, the data track area for recording the data signal must be set as wide as possible. In other words, it is desirable that the area such as a servo track used for recording data signals is small. In order to meet this requirement, only two servo tracks are provided on the tape in this embodiment.

Secondly, it is desirable that the servo track width is wide in order to obtain a wide dynamic range, but for the above-mentioned reason, the servo track width is set to be equal to the data track width in this embodiment. The value of this width is such that even if the tape 1 is displaced considerably to one side in the tape width direction (for example, when the running direction is reversed), it can be pulled in to dynamic tracking (control of the magnetic head to follow the waving of the tape). I wish I had it.

More specifically, for example, the lower servo track ST2 and the servo signal recording / reproducing head S1a shown in FIG.
When the tape 1 is displaced in the + Y direction with respect to the ideal position shown in the figure, the servo track S
The distance until T2 and the servo signal recording / reproducing head S1a are separated in the Y direction is 1.5a. Conversely, when the tape 1 is displaced in the -Y direction, the servo track ST
The distance until 2 and the servo signal recording / reproducing head S1a separate from each other in the Y direction is 0.5a. On the other hand, focusing on the servo track ST1 and the servo signal recording / reproducing head S1b, when the tape 1 is displaced in the + Y direction, 0.
It can be said that there is a displacement margin of a distance of 5a, and there is a displacement margin of a distance of 1.5a when displaced in the -Y direction. Since the servo tracks ST1 and ST2 and the servo signal recording / reproducing head pair S1a and S1b are paired, when the tape 1 is displaced in the + Y direction, the servo signal recording / reproducing head pair S1a is used and the tape 1 is -Y.
Servo signal recording / reproducing head pair S
If 1b is used to pull in the dynamic tracking, a maximum tape displacement margin of a little less than 1.5a can be secured in each of the ± Y directions (if the displacement reaches 1.5a, the reproduction output of the servo signal recording / reproducing head pair becomes 0). , Cannot be drawn into dynamic tracking). Here, assuming that the displacement amount of the tape 1 includes the one-sided displacement when the tape is stopped, and D is set as D <1.
If it is 5a, it becomes possible to pull in the dynamic tracking regardless of the position of the tape 1. Generally, the displacement amount D of the tape 1 can be suppressed to within several tens of μm by providing a tape position regulating means such as a tape guide. Therefore, if D = 30 μm, a> 20.
μm, which is a track width that is sufficiently valid for the width of 50 to 120 μm, which is the width of a thin film magnetic head that is generally used at the present time, and at the same time, sufficiently supports high recording density in the tape width direction. I know that I can do it.

Thirdly, if the track pitch on the tape is made small in order to increase the recording density, the pitch between adjacent heads is generally considered (especially, the pitch between adjacent servo signal recording / reproducing heads is focused here). Must also be small. However, when arranging the adjacent heads on the same magnetic gap line, there are restrictions such as a space required for forming a head structure such as a coil winding. Track pitch = head pitch = track width (here Then, it is difficult to set so that the servo track width = servo signal recording / reproducing head pitch).
To solve such a problem, in the present invention, as described above, four pairs of servo signal recording / reproducing head pairs S1a-S1b,
Since S2a-S2b, S3a-S3b, S4a-S4b are arranged in a zigzag pattern, adjacent servo signal recording / reproducing heads on the same magnetic gap line should have substantially double the head pitch 2a. Thus, it is possible to realize a track and head pattern in which track pitch = head pitch = track width.
This can be said to be a great advantage in reducing the track width. Here, if the servo track width is 20 μm, the pitch between adjacent servo signal recording / reproducing heads on the same magnetic gap line is 40 μm, which is within the range that can be supported even with the current technical level. Recognize.

Next, recording on the servo tracks ST1 and ST2 will be described. FIG. 2 shows a state in which the combination head 3 is moved by the head moving actuator 8 from the state shown in FIG. 1 in the −Y direction by a distance a / 2. In this state, the center of the first servo track ST1 coincides with the center of the servo signal recording / reproducing head S2b, and the center of the second servo track ST2 coincides with the center of the servo signal recording / reproducing head S1a. The centers of the servo tracks ST1 and ST2 in this case indicate ideal positions where the centers of both tracks should originally exist, and it is considered that no servo signal is recorded on the tape 1 in this state. Then, in this state, the tape 1 is run in the + X direction, and the servo signal is reproduced by using the servo signal recording / reproducing heads S1a and S2b.
Record at T2. While the tape 1 is running, waving occurs in the tape 1 due to fluctuations in the tape tension, sway of a rotating body such as a reel, or inclination of a structure (a member that the tape contacts) such as a tape guide. When viewed with the edge of 1 as a reference, the two recorded servo tracks meander in the ± Y directions. However, since the pair of servo signal recording / reproducing heads (S1a and S2b in FIG. 2) used when recording the servo signals are fixed during the servo signal recording, the relative positional relationship between both servo tracks is constant. (The center-to-center distance between the two servo tracks is 19a). Since dynamic tracking is performed while reproducing the servo signals of both servo tracks ST1 and ST2 during recording / reproduction of the data signal (details will be described later), waving that occurs during recording of the servo tracks ST1 and ST2 is substantially related to the data track. Canceled.

The servo tracks ST1 and ST2 are recorded on the other servo signal recording / reproducing head pairs S2a-S.
3b and S3a-S4b are also possible. In that case, the center of the servo signal recording / reproducing head S3b or S4b is aligned with the center of the first servo track ST1, and the servo signal recording / reproducing head S2a is aligned with the center of the second servo track ST2. Alternatively, the head moving actuator 8 is arranged so that the centers of S3b coincide with each other.
The combination head 3 may be moved by. The selection of the servo signal recording / reproducing head pair at the time of recording the servo track is not particularly limited, and any servo signal recording / reproducing head pair may be used.

Next, reproduction of the servo track will be described. As described above, the combination head 3 moves four times in the Y direction for track transfer, but each of them is considered as a static head position, and the state shown in FIG. The state where the combination head is moved in the -Y direction is defined as the second to fourth positions, respectively. In the first position, the servo signal recording / reproducing head pair S1a-S1
b takes the position shown in FIG. That is, with respect to the center of the second servo track ST2,
The center of the servo signal recording / reproducing head S1a is a distance 1 / 2a
Only in the + Y direction. The center of the servo signal recording / reproducing head S1b is apart from the center of the first servo track ST1 by a distance 1 / 2a in the −Y direction.

In this state, the servo track S is recorded by using the first servo signal recording / reproducing head pair S1a-S1b.
When T1 and ST2 are reproduced, respective servo signal reproduction output voltages V are obtained from the servo signal recording / reproducing head pair S1a and S1b. This voltage V corresponds to 1/2 of the reproduction output voltage obtained when the servo signal is reproduced in a state where the center of the arbitrary servo signal recording / reproducing head matches the center of the arbitrary servo track. Similarly, in the second position, the second servo signal recording / reproducing head pair S2a-S2b is used, and in the third position, the third servo signal recording / reproducing head pair S3a-S3b is used.
Thus, at the fourth position, the servo signal reproduction output voltage V is obtained by the fourth servo signal recording / reproducing head pair S4a-S4b.

In summary, the combination head 3 is positioned at static first to fourth positions for track transfer. At each position, with respect to the two servo tracks ST1 and ST2, each head in the corresponding servo signal recording / reproducing head pair has a half pitch (= 1 / 2a: 1 / the width of the servo signal recording / reproducing head). (Corresponding to 2), and the positions are shifted. Here, the track and head used at each position are collectively shown in Table 1 when the tape 1 travels in the + X direction as the forward path and the -X direction as the return path.

[0037]

[Table 1] In Table 1, at any position of the combination head 3, both or one of the servo tracks ST1 and ST2 (which will be described later) is used.

The arrangement of the track and the magnetic head in the track transfer accompanying the serpentine recording / reproducing system has been described above. Next, the dynamic tracking operation will be described. The basic operation of the dynamic tracking is that when the waving occurs on the tape 1 at the head position and the tape 1 moves from the ideal position in the Y direction, the servo track ST1,
The head moving actuator 8 based on the change in the reproduction output voltage of the servo signal recording / reproducing head pair corresponding to ST2.
Is used to move the combination head 3 in the Y direction, thereby guiding the first to fourth data signal recording / reproducing head pairs onto the corresponding data tracks.

This guidance is performed by the actuator control means shown in FIGS. 3 and 4. First, the actuator control means shown in FIG. 3 sets the switch 4 for selecting the reproduction output voltage of either one of the pair of servo signal recording / reproducing heads and the reference voltage V ₀ . Generated reference voltage generator 6 and switch 4
A comparator 5 for comparing the outputs of the servo signal recording / reproducing head selected by the reference voltage generator 6 with each other to generate an error signal, and a head moving actuator 8 based on the error signal obtained from the comparator 5. And an actuator drive circuit 7 for inputting a drive signal to the. The head moving actuator 8 moves the combination head 3 in the Y direction based on a driving signal from the actuator driving circuit 7 so as to follow predetermined data tracks DT1 to DT16. Here, the reference voltage V ₀ is
Servo signal reproduction obtained from the servo signal recording / reproducing head in a state where the center of the servo signal recording / reproducing head corresponding to an arbitrary servo track is displaced by a half pitch (= 1 / 2a) from the center of the servo track. Equal to output.

The actuator control means shown in FIG.
A comparator 5 which compares two outputs obtained from a pair of servo signal recording / reproducing heads to generate an error signal, and a drive signal to a head moving actuator 8 based on the error signal obtained from the comparator 5. And an actuator drive circuit 7 for inputting. Head moving actuator 8
On the basis of a drive signal from the actuator drive circuit 7, the combination head 3 is moved in the Y direction so as to follow the predetermined data tracks DT _{1 to} DT ₁₆ .

In the configuration of the above-mentioned two types of actuator control means, when recording a data signal on the tape 1, first, the combination head 3 is moved to the first position by the head moving actuator 8. Was then traveling tape 1 in the + X direction, while operating the dynamic tracking using servo signal reproducing head pair S1a-S 1 b, the data tracks DT _1, DT ₉ using the data signal recording head W _1, W ₃ Data signal (information) is recorded. At this time, the recorded data signal is immediately reproduced by the data signal reproducing heads R ₁ and R ₃ to check whether or not there is an error in recording, and if there is an error, recording is performed again. Tape 1 is -X in this state
When the end of the direction is reached, the tape running direction is switched to the -X direction, the first head position remains the same, and the data signal recording heads W ₂ and W ₄ and the data signal reproducing head R
₂ and R ₄ are used to simultaneously record and reproduce data signals on the data tracks DT ₅ and DT ₁₃ .

At this time, the servo signal recording / reproducing head pair S
Servo tracks ST1 and ST2 are reproduced using 1a-S1b, and the combination head 3 is adjusted in the Y direction by the actuator control means shown in FIG. 3 or 4. That is, the position adjustment (tracking) of the combination head 3 is performed in a closed loop so that the data tracks DT ₅ and DT ₁₃ are recorded at the positions where they should be originally recorded with respect to the servo tracks ST1 and ST2. When the tape 1 reaches the end in the + X direction, the head 8 is moved by the head moving actuator 8.
To the second position. Next, tape 1 + X
The servo signal recording / reproducing head pair S2a-
The servo tracks ST1 and ST2 are reproduced using S2b, and the position of the combination head 3 in the Y direction is adjusted in a closed loop by the actuator control means, and thereafter, the data is sequentially changed to the data tracks by the combination of the track and the head shown in Table 1. The data signal is recorded as described above. In the above first embodiment, the case where the data signal is not recorded or the data signal is recorded on the tape from which the data signal is erased has been described. However, when the data signal is already recorded (in this case, the servo signal is used). Is also recorded), or when only the servo signal has already been recorded, after moving the combination head 3 to the first position, the tape 1 is moved in the + X direction while the servo signal recording / reproducing head pair S1a, The servo tracks ST1 and ST2 are reproduced using S1b, the position of the combination head 3 is adjusted by the actuator control means, and when the data signal is already recorded, the data signal reproduction heads R ₁ and R ₃ are used to generate the data signal. Can be reproduced. When only the servo signal is already recorded, the data signal recording / reproducing head pair W ₁ -R ₁ and W ₃ -R ₃ can be used to record and reproduce the data signal. Hereinafter, while the combination control unit 3 adjusts the position of the combination head 3 to the proper position in the Y direction by the closed loop by the actuator control means, the data signal is sequentially recorded on the data tracks by the combination of the track and the head shown in Table 1 (already recorded). (Including the case of overwriting the data signal on the data track), or the data signal of the already recorded data track can be reproduced.

Referring to FIG. 5, a second embodiment of the present invention is illustrated. The second embodiment shown in FIG. 5 is similar to the first embodiment shown in FIG. 1, but four sets of servo signal recording / reproducing head pairs S1a-S1b.about.
S4a-S4b are four pairs of servo signal reproducing heads SR1
a-SR1b to SR4a-SR4b,
At the same time, the servo signal recording head pair SW1-SW2
The fixed magnetic head 10 including is newly provided. The magnetic gap between the first and second servo signal recording heads SW1 and SW2 is set along the center line 10a of the fixed head 10. Then, the fixed head 10 is preliminarily positioned and fixed using optical means or the like so that the first and second servo signal recording heads SW1 and SW2 trace the first and second servo tracks ST1 and ST2, respectively. Has been done. Although the fixed head 10 is arranged on the right side of the combination head 3 in FIG. 5, it goes without saying that it may be arranged on the left side thereof.

In the magnetic recording / reproducing apparatus according to the second embodiment, the servo signal recording heads SW1 and SW2 on the fixed head 10 are always on the respective servo tracks ST1 and ST2 regardless of the position of the combination head 3. It will be understood that the servo signals can be recorded at any time regardless of the position of the combination head 3 since they are positioned so as to trace the.

In the above embodiment, the data signal recording heads W _{1 to} W ₄ , the data signal reproducing heads R _{1 to} R ₄ , the servo signal recording / reproducing head pairs S1a-S1b to S4a-S.
4b, servo signal recording head pair SW1-SW2, and servo signal reproducing head pair SR1a-SR1b to SR4a.
Although -SR4b has been described as a thin film head, it will be apparent that the invention can be practiced with a bulk magnetic head.

[0046]

As described above, according to the present invention, no matter how the combination of the information track and the information magnetic gap is changed, at least one servo magnetic gap is at least one servo track. Since it is arranged in the combination head so as to trace a part, the combination head actuator minimizes the amount of positional deviation detected by the positional deviation detecting means in any combination of the information track and the information magnetic gap. Can work to do. Therefore, by improving the tracking accuracy, it is possible to provide a magnetic recording / reproducing apparatus of the serpentine recording / reproducing system with improved recording density and processing speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a combination head and a recording track in a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a combination head and a servo track during recording of the servo track according to the first embodiment of the present invention.

3 is a block diagram showing an actuator control means for realizing dynamic tracking of the combination head of FIG.

FIG. 4 is a block diagram showing another actuator control means for realizing dynamic tracking of the combination head of FIG.

FIG. 5 is a diagram showing a relationship between a recording head and a combination head / fixed head in a magnetic recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a relationship between a combination head and a data track according to a prior art used in a serpentine recording / reproducing system.

[Explanation of symbols]

1 the magnetic tape 2 data track group 3 combination head 4 switches 5 comparator 6 the reference voltage generator 7 actuator driver 8 the head moving actuator DT ₁ to DT ₁₆ data tracks ST1, ST2 servo track W ₁ to _W-4 data signal recording head R ₁ to R ₄ data signal reproducing head S1a-S1b~S4a-S4b servo signal reproducing head pair 10 fixed head SW1, SW2 servo signal recording head SR1a-SR1b~SR4a-SR4b servo signal reproducing head pair

Claims (2)

[Claims] 1. A magnetic recording / reproducing apparatus adapted to a serpentine recording / reproducing system, comprising a plurality of information magnetic gaps for recording and reproducing information on a plurality of information tracks on a magnetic tape, and one or more magnetic gaps. A combination magnetic head including a plurality of servo magnetic gaps for recording and reproducing a servo signal on a servo track; and the combination magnetic head for changing a combination of the information track and the information magnetic gap. Actuator means for relatively displacing in the width direction of the tape, wherein the plurality of servo magnetic gaps are at least irrespective of how the combination of the information track and the information magnetic gap is changed. So that one traces at least part of one of the servo tracks It is arranged in the combination magnetic head, and further comprises a positional deviation detecting means for detecting a positional deviation between the information track and the information magnetic gap based on a servo signal reproduced by the servo magnetic gap. The actuator means also works to adjust the relative positions of the combination magnetic head and the width direction of the magnetic tape so as to minimize the amount of positional deviation detected by the positional deviation detecting means. Characteristic magnetic recording / reproducing device. 2. A magnetic recording / reproducing apparatus adapted to a serpentine recording / reproducing system, comprising a plurality of information magnetic gaps for recording and reproducing information on a plurality of information tracks on a magnetic tape, and one or more magnetic gaps. A combination magnetic head including a plurality of servo signal reproducing magnetic gaps for reproducing a servo signal on a servo track; and 1 for recording a servo signal on the servo track.
A fixed magnetic head including the above servo signal recording magnetic gap; and a relative displacement of the combination magnetic head in the width direction of the tape for changing the combination of the information track and the information magnetic gap. Actuator means, wherein at least one of the plurality of servo signal reproducing magnetic gaps is at least a part of one of the servo tracks, no matter how the combination of the information track and the information magnetic gap is changed. Is arranged in the combination magnetic head so as to trace the position of the information track. Further, the positional deviation between the information track and the information magnetic gap is detected based on the servo signal reproduced by the servo signal reproducing magnetic gap. A position deviation detecting means, The step also functions to adjust the relative position between the combination magnetic head and the width direction of the magnetic tape so as to minimize the amount of positional deviation detected by the positional deviation detecting means. Magnetic recording / reproducing device.