JPS59129908A - Magnetic recording device - Google Patents

Abstract

PURPOSE:To prevent an excessive erasion and an unerased part of a track edge by setting a delay time of an operation start and an operation stop of an erase head to a read/write head to the time when the outermost circumferential and the innermost circumferential tracks pass through both heads, respectively. CONSTITUTION:On the recording surface side of a magnetic disk, a delay time of an operation start of an erase head 11b to an operation start of a read/write head 11a is set to the time when the outermost circumferential track on its recording surface passes through between both heads 11a, 11b, and also a delay time of an operation stop of the head 11b to an operation stop of the head 11a is set to the time when the innermost circumferential track on its recording surface passes through between both heads 11a, 11b. Also, on the recording rear side, too, a delay time of an operation start and an operation stop of an erase head 13b to a read/write head 13a is set in the same way. In this way, with regard to all the tracks on both face side recording surfaces, it becomes possible to prevent leaving an unerazed part or causing an excessive erasion of a track edge.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a magnetic recording system that magnetically records information by arranging a pair of tunnel erase head mechanisms consisting of a read/write head and an erase head to face each other on both sides of a magnetic recording medium. Regarding equipment.

[Technical background of the invention and its problems]

A magnetic recording device using a tunnel erase head mechanism consisting of a read/write head and an erase head, as shown in FIG. A write head 2 and an erase head 3 are provided with a predetermined interval and the read/write head 2 is placed in front.The read/write head 2 records information on the recording track 4, and the erase head 3 performs a track nip. I try to clean up the tracks by erasing them. However, since the read/write head 2 and the erase head 3 are separated from each other in this way, in order to match the recording position of information with the erase position of the track nip, it is necessary to move the erase head 3 when the read/write head 2 starts and stops operating. It is necessary to slightly delay the start and stop timing of the operation. By the way, although the distance between the read/write head 2 and the erase head 3 is fixed, the circumferential speeds of the outermost track and the innermost track of the magnetic disk 1 are different. The time it takes for the head to pass between the two heads 2 and 3 is different. That is, the outermost track has the shortest passing time, and the innermost track has the longest passing time. Therefore, in order to eliminate the unerased track nip by the erase head 3, the delay time for starting the operation of the erase head 3 should be adjusted to the passing time of the outermost track.
It is necessary to adjust the delay time for stopping the operation of the erase head 3 to the passage time of the innermost track. However, in this method, the start of the erase operation by the erase head 3 is synchronized with the passage time of the outermost track, and the end of the erase operation is synchronized with the passage time of the innermost track. Although there is no problem of unerased data on tracks that are inner than the track, or on tracks that are outer than the innermost track when the erasing operation is stopped, there is a problem of overerasing. Particularly when the centers of both heads 2 and 3 are aligned with the center of the track, it is good. When the centers of both heads 2 and 3 are shifted from the center of the track, so-called off-track, a part of the recorded area may be erased. There are 15 inherent problems.

By the way, a double-sided recording type magnetic recording device has been developed in which both sides of a magnetic disk are used as recording surfaces, and the above-mentioned tunnel erase head mechanism is arranged facing each other on each recording surface. Head portions 5a and 6a of the front side head mechanism 5 and the back side head mechanism 6 of the magnetic disk 1 are disposed facing each other and are offset in the radial direction of the magnetic disk 1. For example, the head portion 5a of the front side head mechanism 5 is disposed a few tracks more toward the outer circumferential side of the magnetic disk 1 than the head portion 6fL of the rear side head mechanism 6. This is because it is necessary to support the opposing positions of each head section 5a, 6a with a pad, and each head mechanism 5, 6 is formed with a pad section 5b, 6b.

Further, the number of tracks on both sides of the magnetic disk 1 is configured to be the same. Therefore, on the outer circumferential side of the magnetic disk 1, the outermost track is formed with the front side shifted several tracks further outward than the back side, and conversely, on the inner circumferential side, the back side is shifted outward by several tracks. The innermost track is formed by being shifted inward by several tracks.

Conventionally, in such a double-sided recording type magnetic recording device, the erase operation start by the erase head 3 is delayed according to the passing time of the outermost track on the front side, and the erase operation is stopped at the innermost track on the back side. It is known that the delay time is set according to the passing time of the erase head to avoid leaving unerased tracks. In this case, there is a risk that there will be more over-erasing than in the case of the single-sided recording method described above, and that part of the track will be erased so much during off-track that it will become impossible to read the information.

[Purpose of the invention]

This invention was made in view of these points, and it is a single device in which the read/write head and the erase head are separated.
In a device that performs double-sided recording by arranging a pair of tunnel erase head mechanisms on both sides of a magnetic recording medium to face each other,
Excessive erasing by the head can be suppressed as much as possible.
It is an object of the present invention to provide a magnetic recording device that does not have the possibility of becoming unable to read information.

[Summary of the invention]

In this invention, a pair of tunnel erase head mechanisms in which a read/write head and an erase head are separated from each other are disposed facing each other on the image recording surface of a disc-shaped magnetic recording medium so as to be offset from each other in the radial direction. In a magnetic recording device that magnetically records information over multiple tracks, the operation of the erase head relative to the read/write head is started for each tunnel erase head mechanism on each recording surface when the outermost track on each recording surface passes between the two heads. In addition, the completion of the operation of the erase head relative to the read/write head is set to be delayed by the time required for the innermost track on each recording surface to pass between the two heads.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 3, one end of the read/write head 11a of the front head 11 and one end of the erase head 11b are connected to the common terminal C of the first head driver 12, and the read/write head 13a of the rear head 13 is connected to the common terminal C of the first head driver 12. One end and one end of the erase head 13b are connected to a common terminal C of the second head driver 14.

The front side head 11 and the rear side head 13 are arranged opposite to each other with respect to a magnetic disk (not shown) in the same manner as shown in FIG. For example, the side select signal SS is directly inputted to the first head driver 12, and the side select signal SS is directly inputted to the front Be second head driver 14. A select signal SS is inputted via the inverter 15.The side select signal sS becomes a high level signal when information is written to or read from the front side recording surface of the magnetic disk, and conversely, when information is written to or read from the front side recording surface of the magnetic disk. When reading, the signal becomes a low level signal.The head drivers 12 and 14 each receive a high level signal υ,
The common terminal C is controlled to the ground potential. The side select signal SS is also a two-manufactured first AND gate 1.
It is input to one input terminal of the second AND gate 17 of the two-manpower type via the inverter 15 at □. Said both andcoot 16
．． A write signal WS serving as a command to perform information consolidation is inputted to the other input terminals of the input terminals 17, respectively. This write signal WS is transmitted to the front head 11 by a circuit (not shown).
and the read/write head lla, 13 of the back side head 13.
It acts as a trigger to supply a voltage signal to the other end of a. The write signal WS is also input to the D input terminal of the D-type flip-flop 18. The output of the first AND gate 16 is input to the B input terminal of the first monostable circuit 19, and is also input to the input terminal which is the negative input terminal of the second monostable circuit 20. The output of the second AND gate 17 is input to the third monostable circuit 210B input terminal, and the negative input terminal of the fourth monostable circuit 22 is input to the A input terminal. Note that the first and third single constant circuits 19.21
The A input terminal, which is the negative input terminal of
The B input terminal of the monostable circuit 20°22 is connected to the +V terminal.

The first and third monostable circuits 19 and 21 invert the Q output terminal output from low level to high level in response to the rise of the B input terminal input changing from low level to NO level, and when a set time has elapsed. The Q output terminal output is later returned to a low level, and the setting time of the first monostable circuit 19 is such that the outermost track on the front side recording surface of the magnetic disk is the read/write head l of the front side head 11.
The set time of the third monostable circuit 21 is set to the time required for the outermost track on the back side recording surface of the magnetic disk to pass between the read/write head of the back side head 13. 13m and the erase head 13b.

The second and fourth monostable circuits 20 and 22 invert the Q output terminal output from low level to high level in response to the falling edge 9 when the A input terminal input changes from high level to low level, The Q output terminal output is returned to a low level after a set time has elapsed, and the set time of the second monostable circuit 2o is such that the innermost track on the front side recording surface of the magnetic disk is located at the top of the front side head 11. Dry 1 head Il
The setting time of the fourth monostable circuit 22 is set to the time required for the innermost track on the back side recording surface of the magnetic disk to pass between the read/write head 13a of the back side head 13. and erase head 1
31).

The outputs of the Q output terminals of the monostable circuits 19, 20, 21, and 22 are inputted to the T input terminal of the flip-flop 18 via the Nordart 23. The flip-flop 18 sets the input level to the D input terminal in response to the rise of the input to the T input terminal, and its output terminal is connected to the base of a PNPN upper type resistor 25 via a resistor 24. . The transistor 25 has its emitter connected to the +V terminal, and its collector connected to the other end of the erase head llb via a resistor 26 and a diode 27, and also to the other end of the erase head 13b via the resistor 26 and diode 28. connected to the end. A resistor 2 is connected between the base and emitter of the transistor 25.
9 is connected. The flip-flop 18 and the monostable circuits 19 to 22 are reset by an initial reset circuit 3θ when the power is turned on.

In the embodiment of the present invention having such a configuration, a high level side select signal SS specifying the front side of the magnetic disk is used.
When input, the common terminal C of the first head driver 12 becomes the ground level. When the write signal ws is input in this state, the output of the first AND gate 16 becomes high level. As a result, the Q output terminal output of the first monostable circuit 19 becomes high level. On the other hand, at the input timing of the write signal WS, the read/write head-1 of the front side head 11
1m starts operation immediately.

Then, at the timing when the outermost track on the front side recording surface of the magnetic disk moves from the read/write head lla position to the erase head llb position, the Q output terminal output of the first monostable circuit 19 is inverted to a low level. The output of the Sinoadat 23 rises to a high level, and the D-type frizzo flop 18 sets the input state of the write signal ws, that is, the high level state. As a result, the output from the same output terminal of the flip-flop 18 becomes low level, and 9) the transistor 25 is turned on.

As a result, erase head llb starts operating after a set time delay. After that, when the input of the write signal WS disappears, the first AND 16 output becomes low level υ
, the Q output terminal output of the second monostable circuit 20 becomes high level. On the other hand, when the input of the write signal WS is stopped, the read/write head 11a immediately stops operating. Then, at the timing when the innermost track on the front side recording surface of the magnetic disk moves from the read/write head lla position to the erase head llb position, the output from the Q output terminal of the second monostable circuit 2θ is inverted to low level. The output of the NOR route 23 rises to a high level, and the D-type flip-flop 18 sets the input stop state of the write signal WS, that is, the low level state. As a result, the output from the same output terminal of the flip-flop 18 becomes the NO level, and the transistor 25 is turned off. As a result, the erase head llb stops operating after a set time delay.

In this way, on the front side recording surface of the magnetic disk, the erase head ll responds to the start of operation of the read/write head 11a.
The delay time for the start of the operation of b is set to the time for the outermost track on the front and side recording surfaces to pass through the dots lla and 11brlJ1, and the delay time for the start of the operation of the erase head llb in response to the cessation of the operation of the read/write head lla is set. Since the delay time is set to the time it takes for the innermost track on the front side recording surface to pass between both heads lla and Ilb, no track nip remains unerased for all tracks on the front side recording surface. Also, the number of over-erased areas can be minimized.

Further, when a low-level side select signal SS specifying the back side of the magnetic disk is input, the common terminal C of the second head driver 14 becomes the ground level. When the write signal WS is input in this state, the second AND gate 1
7 output becomes high level. As a result, the Q output terminal output of the third monostable circuit 21 becomes high level. On the other hand, the read/write head 13a of the back side head 13 immediately starts operating at the input timing of the write signal WS. Then, the outermost track on the back side recording surface of the magnetic disk is moved from the read/write head 13a position to the erase head 13.
At the timing of moving to position b, the Q output terminal output of the third monostable circuit 21 is inverted to low level, and as a result, the output of the dino gate 23 rises to high level, and the D-type Noritsubu flop 18 inputs the write signal WS. state, ie, a high level state. As a result, the output from the same output terminal of the flip-flop 18 becomes low level, and the transistor 25 is turned on. As a result, the erase head 13b starts operating after a set time delay. Thereafter, when the input of the write signal WS disappears, the output of the second AND/DART 17 becomes a low level, and the output of the Q output terminal of the fourth monostable circuit 22 becomes a NO level.

On the other hand, when the input of the write signal WS is stopped, the read/write head 13a immediately stops operating. Then, at the timing when the innermost track on the back side recording surface of the magnetic disk moves from the read/write head 13h position to the erase head 13b position, the output of the Q output terminal of the fourth monostable circuit 22 is inverted to low level. The output of the NOR gate 23 rises to a high level, and the D-type flip-flop 18 sets the write signal WS input halt state, that is, a low level state. As a result, the output from the same output terminal of the flip-flop 18 goes to the NO level, and the transistor 25 is turned off. As a result, the erase head 13b stops operating after a set time delay.

In this way, on the back side recording surface of the magnetic disk, the erase head 13 responds to the start of operation of the read/write head 13h.
The delay time for the start of the operation of the erase head 1.9 b is set to the time required for the outermost track on the back side recording surface to pass between both heads 13a and 13b, and the operation of the erase head 1.9 b is stopped when the read/write head 13a stops operating. Since the delay time is set to the time it takes for the innermost track on the back side recording surface to pass between both heads 13a and 13b, there will be no unerased track nip for all tracks on the back side recording surface. In addition, over-erased areas can be minimized as much as possible.

In this way, it is possible to prevent unerased track nips on all tracks of both recording areas of the magnetic disk, and to suppress overerasing as much as possible, thereby preventing information from becoming impossible to read due to overerasing.

〔Effect of the invention〕

As described in detail above, according to the present invention, a pair of tunnel erase head mechanisms in which a read/write head and an erase head are spaced apart are disposed facing each other on both sides of a magnetic recording medium to perform double-sided recording. Therefore, it is possible to provide a magnetic recording device that can suppress "over-erasing" due to data as much as possible, and is free from the risk of becoming unable to read information.

[Brief explanation of the drawing]

FIG. 1 is a partial diagram showing the arrangement of the tunnel erase head mechanism with respect to the magnetic disk, FIG. 2 is a partial diagram showing the arrangement of the tunnel erase head mechanism with respect to the magnetic disk in a double-sided recording system, and FIG. FIG. 2 is a circuit diagram showing an example. 11...Front side-\rad, 13...Front side head,
18...D type frizzo flop, 19, 20, 21
゜22... Monostable circuit, 25... PNP type transistor.

Claims (1)

[Claims] A pair of tunnel erase head mechanisms, in which a read/write head and an erase head are spaced apart along the rotational direction of the magnetic recording medium, are installed on each recording surface of a disc-shaped magnetic recording medium with recording surfaces on both sides. In a magnetic recording device that magnetically records information over a plurality of tracks on both sides of the magnetic recording medium, which are arranged facing each other while being shifted in the radial direction of the recording medium, erasing is performed on the read/write head for each tunnel erase head mechanism on each recording surface. The start of head operation is delayed by the time it takes for the outermost track on each recording surface to pass between the two heads, and the end of operation of the erase head for the read/write head is set until the innermost track on each recording surface passes between the two heads. A magnetic recording device characterized in that a delay is set by the time required to pass between P.