JPH06119616A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate the adverse effect of an erase head against the signal-to- noise ratio of reproduced data by making the switching means, which is con nected to the erase head coil in parallel, closed during a data reading and making the means open during a data writing. CONSTITUTION:When a disk shaped magnetic recording medium 9 such as a floppy disk is moved in the direction shown by an arrow 9A during a reading of recorded data, a magnetic path (shown by a solid line) is generated in a reading and writing head 8 and an induced voltage is generated in a coil 81 by the changes in magnetic flux in the magnetic. By detecting this voltage, the data are read. During a reading, a switch 74 is in an open condition, a switch 75 is in a closed condition, no current flows in an erase head 7 and a coil 71 is short circuited by the closure of the switch 75. Since the coil 71 is short circuited by the switch 75, a reverse magnetomotive force is generated, the changes in magnetic flux is almost made to zero and no induced voltage is generated in a coil 81 as a noise signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reading data from a disk-shaped magnetic recording medium such as a floppy disk.
The present invention relates to a magnetic recording / reproducing device for writing.

[0002]

2. Description of the Related Art FIG. 2A is a configuration diagram showing an example of a head configuration of a conventional magnetic recording / reproducing apparatus, and shows a case where a tunnel erase head is used as an erase head.
As shown in FIG. 2A, the read / write head 1 and the erase head 2 have coils 11 and 21, cores 12 and 22, and gaps 13 and 23 to 24. Also, heads 1 and 2
And a separate part SEP made of glass, for example.
Are provided to increase the magnetic resistance between the heads.

In the head structure shown in FIG. 2A, at the time of reading, a disk-shaped magnetic recording medium 3 such as a floppy disk.
Moves in the direction indicated by arrow 3A, the read / write head 1
A magnetic path as shown by the solid line is generated in the coil, and an induced voltage is generated in the coil 11 due to a change in magnetic flux in this magnetic path. Data can be read by detecting this induced voltage. No current flows through the erase head 2 during reading.

In the head structure of FIG. 2A, during writing, a magnetic path shown by a solid line is generated in the core 12 based on the write current flowing through the coil 11. This magnetic path is also generated in the magnetic recording medium 3 as shown in the figure, and the medium 3 is magnetized based on the magnetic flux in the magnetic path and data is recorded. At the time of writing, a current flows through the erase head 2, and as shown in FIG. 2B, the old write data 31 and the new write data 32 on the track are partially erased as indicated by erased portions 33 and 34. The erased portions 33 and 34 are provided in order to keep the distance from the adjacent track and to prevent the signal-to-noise ratio from being deteriorated by detecting the old write data 31.

FIG. 3A is a structural view showing another example of the head structure of a conventional magnetic recording / reproducing apparatus, and shows a case where a preceding erase head is used as an erase head. Figure 3
As shown in (a), the positional relationship between the erase head and the read / write head is opposite to that shown in FIG. 2 (a), and the erase head 4 and the read / write head 5 have coils 41, 51 and cores. 42 and 52 and gaps 43 and 53. Further, a separate part SEP made of, for example, glass is provided between the heads 4 and 5 to increase the magnetic resistance between the heads.

In the head structure shown in FIG. 3A, at the time of reading, a disk-shaped magnetic recording medium 6 such as a floppy disk.
Moves in the direction indicated by arrow 6A, the read / write head 5
A magnetic path shown by a solid line is generated in the coil, and an induced voltage is generated in the coil 51 due to a change in magnetic flux in this magnetic path. Data can be read by detecting this induced voltage. No current flows through the erase head 2 during reading.

In the head structure of FIG. 3A, during writing, a magnetic path shown by a solid line is generated in the core 52 based on the write current flowing through the coil 51. This magnetic path also occurs in the magnetic recording medium 6 as shown in the same figure, and the medium 6 is magnetized based on the magnetic flux in the magnetic path, and data is recorded. At the time of writing, a current flows through the erase head 4, and the old write data 61 on the track is erased as shown in FIG. 3B.
As shown by, the data is erased, and new data 63 is written in the erased portion. In this way, when the preceding erase head 4 is used, the old write data 61 is completely erased, so that the signal-to-noise ratio based on the data 61 does not deteriorate.

[0008]

However, in the above-described conventional head configuration, the gaps 23 to 24 of the erase heads 2 and 4 are generated based on the magnetomotive force on the medium 3 or 6 at the time of reading data, that is, at the time of reproducing. 43
Also reads the data, core 22, 12 or core 42,
At 52, a magnetic flux change occurs as shown by the dotted line in FIG. 2 (a) or FIG. 3 (a). Due to this change in magnetic flux, the coil 11
Alternatively, an induced voltage is generated as a noise signal at 51, which deteriorates the signal-to-noise ratio of read data. In particular, the preceding erase head has a large gap 43, so that the generated noise signal level is also high and has a great influence on the signal-to-noise ratio.

The present invention has been made in consideration of the above circumstances, and an object thereof is to make it possible to make the noise signal level due to the erase head at the time of reproduction not affect the signal-to-noise ratio. It is to provide a magnetic recording / reproducing apparatus.

[0010]

In order to solve the above problems, the present invention provides a magnetic recording / reproducing device in which a read / write head and an erase head are arranged close to each other in the longitudinal direction of a track so as to scan a single track. The apparatus is provided with a switch means connected in parallel to the coil of the erase head, and the switch means is closed when reading data and opened when writing data.

[0011]

In the magnetic recording / reproducing apparatus according to the present invention, the switch means 75 is connected in parallel to the coil 71 of the erase head 7 as shown in FIG. Switch means 7 during playback
5 is closed and the coil 71 is short-circuited. Therefore, even if the magnetic recording medium 9 moves to cause a magnetic flux change in the cores 72 and 82 via the gap 73, a counter electromotive force, that is, a counter electromotive force is generated in the coil 71, and the magnetic flux change is suppressed. As a result, the change in magnetic flux generated in the cores 72 and 82 becomes very small, and the noise signal level on the coil 81 due to the gap 73 becomes extremely low.
It hardly affects the signal-to-noise ratio of read data.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic recording / reproducing apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, showing a case where a preceding erase head is used as an erase head. Erase head 7, read / write head 8
Is the coil 71, 81, the core 72, 82 and the gap 7
3 and 83. Also, between the heads 7 and 8,
For example, a separate part SEP made of glass is provided,
The magnetic resistance between the heads is increased.

In the head configuration of FIG. 1, when the disk-shaped magnetic recording medium 9 such as a floppy disk moves in the direction shown by an arrow 9A when reading recorded data, the read / write head 8 has a magnetic path indicated by a solid line. Occurs, and an induced voltage is generated in the coil 81 due to the change in the magnetic flux in this magnetic path. Data can be read by detecting this induced voltage. At the time of reading, the switch 74 is in the open state and the switch 75 is in the closed state, so that no current flows through the erase head 7, but the coil 71 is in the short-circuit state due to the switch 75 being closed.

When recording data is read by the read / write head 8, the data is also read by the gap 73 of the erase head 7 based on the magnetomotive force on the magnetic recording medium 9, and the core 72,
Although a magnetic flux change is about to occur as indicated by a dotted line at 82,
Since the coil 71 is short-circuited by the switch 75 as described above, a counter electromotive force, that is, a counter electromotive force is generated, and the change in magnetic flux becomes almost zero. As a result, the induced voltage does not occur in the coil 81 as a noise signal, and the deterioration of the signal-to-noise ratio of the data detected by the coil 81 can be prevented.

When writing data, the switch 74 is closed and the switch 75 is opened, the erase current i is supplied to the coil 71 from the power supply terminal T, and the old write data 61 is erased as shown in FIG. 3B. The erase current i is determined by the supply voltage to the power supply terminal T and the resistance value of the resistor 76.

Although the above embodiment has been described with respect to the preceding erase head, the present invention is not limited to this, and can be similarly applied to a tunnel erase head and has the same effect.

[0018]

As described above, the magnetic recording / reproducing apparatus according to the present invention can eliminate the signal detection at the time of reproduction by the erase head, so that the signal-to-noise ratio of the reproduced data detected by the read / write head can be eliminated. This has the effect of eliminating the adverse effects of the erase head.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional magnetic recording / reproducing apparatus and a magnetic recording erasing pattern diagram in the example.

FIG. 3 is a configuration diagram showing another example of a conventional magnetic recording / reproducing apparatus and a magnetic recording erasing pattern diagram in the example.

[Explanation of symbols]

 7 Erase Head 8 Read / Write Head 9 Magnetic Recording Medium 71, 81 Coil 72, 82 Core 73, 83 Gap 74, 75 Switch 76 Resistor SEP Separate Section

Claims (1)

[Claims] 1. A magnetic recording / reproducing apparatus in which a read / write head and an erase head are arranged close to each other in the track longitudinal direction so as to scan on a single track, and a switch means connected in parallel to a coil of the erase head. The magnetic recording / reproducing apparatus is characterized in that the switch means is closed when reading data and opened when writing data.