JPS6215930B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head used in a magnetic disk storage device such as a floppy disk.

Conventionally, this type of magnetic head was disclosed in Japanese Patent Application Laid-Open No. 55-42302.
The structure shown in the publication is adopted. That is, as shown in FIGS. 1 to 3, it is composed of a recording/reproducing head 1 and an erasing head 2. The recording/reproducing head 1 is composed of a recording/reproducing winding 3 and a recording/reproducing magnetic path 4, and is used for recording/reproducing. A recording/reproducing gap 5 is provided in a part of the magnetic path 4. When current flows through the recording/reproducing winding 3 during recording, most of the magnetic flux passes through the recording/reproducing magnetic path 4, but a portion becomes recording leakage magnetic flux 6.
It passes through the magnetic layer 8 on the surface of the recording medium 7, reverses the magnetization of the magnetic substance, and forms a track 9. On the other hand, the erase head 2 consists of an erase winding 10, a first erase magnetic path 11A, and a second erase magnetic path 11B, and erase gaps 12A, 12B are provided in a part of each erase magnetic path 11A, 11B. When an erase current flows through the erase winding 10 during recording, most of the erase magnetic flux passes through the magnetic paths 11A and 11B, but a portion becomes the erase magnetic flux 13 and passes through the magnetic layer 8, but the erase current is a direct current. Therefore, DC cancellation will be performed. Since the two magnetic paths 11A and 11B of the erasing head 2 are arranged on both sides of the recording/reproducing magnetic path 4, it is the track 9 that is erased with direct current.
As a result, a track 15 narrower than the track 9 remains. Since both sides 14A and 14B of the track 15 are DC-cancelled, no noise is generated during reproduction.

By the way, in a simple device such as a floppy disk, due to the feeding system, expansion and contraction of the medium, expansion and contraction of the main body, etc., as shown in Figure 4, the
Off-track, where the relative position shifts by about 130 μm, may occur. With this off-track,
The recording/reproducing head 1 rides on the Nth track _15N that it attempts to read, but the erasing magnetic path 11 of the erasing head 2
On the A side, track 15 _{N +1} is adjacent to track 15 N.
I will be riding on. In this case, the erase head 2 is also the same in principle as the recording/reproducing head 1, so if the erase head 2 rides on the track 15 _N+1 , it picks up the magnetic flux of this track 15 _N+1 , and the erase head Attempt to pass magnetic flux through 2. However,
Since the erase head 2 has an open magnetic path, the picked up magnetic flux enters the recording/reproducing magnetic path 4 of the recording/reproducing head 1 as leakage flux, as shown in FIG. As a result, the erase magnetic path 1 for the track _15N shown in FIG.
1B output and track 15 _N+1 shown in Figure 6c.
The output of the erasing magnetic path 11A is superimposed on the output, resulting in waveform distortion as shown by the dotted line in FIG.
A read error will occur.

The present invention was made in view of the above points, and an object of the present invention is to obtain a magnetic head that does not cause waveform distortion even when off-track occurs and can prevent reading errors. .

A technique for achieving the object of the present invention will be explained based on FIG. 7. Components that are the same as those shown in FIGS. 1 to 6 are designated by the same reference numerals, and description thereof will be omitted.
The first technology consists of a recording/reproducing head 1 and an erasing head 2.
A distance d is provided between the cursor and the cursor, which is not affected by the leakage flux caused by the erasing head 2.
This distance d varies depending on the material, processing conditions, shape, etc., and is preferably determined experimentally in each case.
If the interval d is about 20 to 25 times the width gH of 2B,
No leakage flux effects occur.

Therefore, in the off-track case where the recording/reproducing head 1 and the recording track position are relatively shifted, even if the erasing head 2 is located on an adjacent track and picks up the magnetic flux, the recording/reproducing head 1 and the erasing head 2 Due to the interval d between them, the influence of leakage flux is eliminated, and the leakage flux does not enter the recording/reproducing magnetic path 4 of the recording/reproducing head 1, so that the output waveform of the recording/reproducing head 1 is not distorted and reading errors are prevented. be done.

In this case, if the area around the core material of the erase head 2 is plated with copper to convert the loss into eddy current loss, the influence of leakage flux can be greatly prevented.

Furthermore, as a second technique, the influence of leakage flux can be further reduced by making the magnetic permeability of the core material of the recording/reproducing head 1 different from the magnetic permeability of the core material of the erasing head 2. That is, by reducing the magnetic permeability of the core material of the erase head 2 within a range that does not interfere with the erase action, the erase head 2 will be less likely to pick up magnetic flux from the track, and leakage will be prevented.

In the present invention, the recording/reproducing head and the erasing head are configured to have different magnetic permeabilities, and the magnetic permeability of the erasing head is lowered, so that even when off-track occurs, distortion does not occur in the output waveform of the recording/reproducing head. Therefore, it is possible to prevent reading errors with a simple structure.

[Brief explanation of the drawing]

Figure 1 is a plan view showing a conventional magnetic head, Figure 2 is a plan view showing a conventional magnetic head;
The figure is a side view, Figure 3 is an explanatory diagram showing the recording track, Figure 4 is an explanatory diagram showing off-track, and Figure 5 is an explanatory diagram showing the off-track.
The figure is a side view showing the magnetic flux distribution, FIG. 6 is a waveform diagram thereof, and FIG. 7 is a diagram for explaining a technique for preventing reading errors. 1...recording/reproducing head, 2...erasing head, 4
...recording/reproducing magnetic path, 11A...first erasing magnetic path,
11B...second erase magnetic path, d...interval.

Claims (1)

[Claims] 1 consisting of a recording/reproducing head and an erasing head, the erasing head having a first erasing magnetic path and a second erasing magnetic path, the first erasing magnetic path and the second erasing magnetic path being In the magnetic heads disposed on both sides of the magnetic path of the recording/reproducing head, the magnetic permeability of the core material of the erasing head is made different from the magnetic permeability of the core material of the recording/reproducing head, and the magnetic permeability of the core material of the erasing head is made different. A magnetic head characterized by a low magnetic head.