JP2809542B2 - Magnetic head device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to a 3.5 inch FDD.
The present invention relates to a magnetic head device mounted on a (floppy disk drive).

[0002]

2. Description of the Related Art FIG. 3 is a perspective view showing a conventional magnetic head device for FDD disclosed in, for example, JP-A-2-31312. In FIG. 3, reference numeral 1 denotes a first magnetic core having gaps on both sides thereof. A forming joint surface is formed. Reference numerals 2 and 3 denote second and third magnetic cores forming an erase gap and a recording / reproducing gap with the first magnetic core 1 interposed therebetween.
4 is a recording / reproducing gap, 5 is an erasing gap, 6 is a mold glass, 7 is a recording / reproducing coil wound around the third magnetic core 3, and 8 is an erasing coil wound around the second magnetic core.

Next, the operation will be described. When recording data on a floppy disk (hereinafter referred to as FD) is passed through the recording current to the recording coil 7, to concentrate the magnetic field in which the current is generated in the recording reproducing gap 4 generates a leakage magnetic field, the magnetization of the FD Then, the magnetization pattern is recorded as data. When reproducing data recorded on the FD, the recording / reproducing gap 4 is set to the relative speed v with respect to the FD.
The reproducing output is obtained by moving the magnetization reversal region of the magnetization pattern recorded on the FD in the step (1). The recording / reproducing gap of a magnetic head device mounted on a 3.5-inch floppy disk drive (hereinafter abbreviated as FDD) allows two operations to be performed in the same gap without using separate gaps for recording and reproducing data. I do. In order to increase the reproduction output, from the viewpoint of the recording operation with respect to the recording / reproducing gap 4, a recording / reproducing gap length and a magnetomotive force for obtaining a recording magnetic field for magnetizing the FD to the saturation magnetization region are necessary. The recording / reproducing gap length is required so that the transition length of the recording magnetization reversal becomes small and the recording demagnetization effect becomes small.

From the viewpoint of the reproducing operation, when the wavelength of the magnetization pattern recorded on the FD is λ, the output loss at the time of reproduction is expressed by the equation (1). The smaller the value, the higher the reproduction output.

[0005]

(Equation 1)

The maximum recording wavelength of the conventional 4 MB FDD is 1
9.84 μm, and the minimum recording wavelength is 1.46 λm. The length of the recording / reproducing gap 4 of the conventional magnetic head device equipped with the 4MBFDD is set in a range of 0.35λm or more and 0.45λm or less. The purpose of setting the gap length is to mainly obtain a sufficient reproduction output when recording and reproducing the minimum wavelength of 1.46 λm.

Therefore, when recording the maximum recording wavelength of 19.84 μm, it is difficult to sufficiently saturate the FD due to the magnetic characteristics of the FD for recording this wavelength with the recording / reproducing gap length of the conventional magnetic head. there were. That is, when the recording / reproducing gap length is reduced, the recording magnetic field is limited by the gap length even when the magnetomotive force is increased to 19.8.
It was difficult to sufficiently magnetize the deep portion of the magnetic layer of the FD for recording a wavelength of 4 μm.

[0008] a feature called the 4MBFDD have backward compatibility, which is dedicated floppy for recording and reproducing a storage capacity of Ann format 1 megabyte 1MBF D (MFM recording method recorded data by 4MBFDD - Disk ) Is reproduced by 1MB FDD (hereinafter, dedicated FDD for recording and reproducing unformatted 1 megabyte storage capacity by M recording method), a function to guarantee that the soft error rate is 10 ^-9 or less, and 4MB
1MBFD with data recorded by FDD is 2MB
FDD (FD for recording and reproducing unformatted 1MB and 2MB recording capacity by MFM recording method)
D) a function that satisfies the above guarantees when played back,
2MBFD recorded data by 4MBFDD
(Exclusive floppy disk for recording / reproducing unformatted 2MB storage capacity by MFM recording method)
In these cases, the data recording is performed by the recording magnetic field generated from the gap length of the conventional magnetic head.

[0009]

For example, the recording / reproducing gap length of a magnetic head device mounted on 1 MBFDD is about 1.2 μm, and 1 MBFD recorded with this gap length is used.
And 4MBFDD of the conventional magnetic head equipped with.
Compared to the case where 1 MBFD recorded with a gap length of 35 μm to 0.45 μm is reproduced by 1 MBFDD,
There is a problem that the output for reproducing the 1 MBFD recorded by the 4 MBFDD is small, the resolution is high, and it is difficult to satisfy the soft error rate of 10 ^-9 or less at this time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and satisfies the backward compatibility,
It is an object of the present invention to provide a magnetic head device capable of recording and reproducing 4 megabytes of unformatted data by the M recording method.

[0011]

The magnetic head device according to the present invention has a recording / reproducing gap length of 0.45 .mu.m or more.
This is enlarged to 55 μm or less.

[0012]

According to the present invention, the recording / reproducing gap length can be increased by increasing the magnetization region of the magnetic layer of the FD in the depth direction when data is recorded on the 1MBFD using the 4MBFDD. This FD is 1MB FDD or 2MB
The output during FDD reproduction can be increased and the resolution at the time of reproduction can be lowered at the same time. The soft error rate of 10 ^-9 or less in backward compatibility can be satisfied, and the same level of soft error can be achieved in recording and reproduction of 4 megabytes. Satisfy the rate.

[0013]

【Example】

Embodiment 1 FIG. In FIG. 1, reference numeral 1 denotes a first magnetic core;
A gap-forming joining surface is formed on both surfaces without a magnetic separation layer. Reference numeral 2 denotes a second magnetic core, which forms an erase gap 5 with the first magnetic core 1 interposed therebetween. Reference numeral 3 denotes a third magnetic core, which forms a recording / reproducing gap 4 with the first magnetic core 1 interposed therebetween. Reference numerals 6a and 6b denote back cores, which are a first magnetic core 1 and a third magnetic core 3, respectively.
And a magnetic member attached for the purpose of closing a magnetic path formed by the first magnetic core 1 and the second magnetic core 2. Reference numeral 7 denotes a recording / reproducing coil wound around the third magnetic core 3, and reference numeral 8 denotes an erasing coil wound around the second magnetic core 2.

FIG. 2 is an enlarged plan view of the first recording / reproducing gap portion. The gap shown by b in the figure is the recording / reproducing gap length, and this length is related to determining the performance of the magnetic head device. Dominant. In the present invention, the gap length is set to 0.45 μm or more and 0.55 μm or less.

When data is recorded on the FD, the FDD
In the magnetic head device, the recording / reproducing gap 4 is slid in contact with the FD at a relative speed v, and the recording magnetic field generated from the recording / reproducing gap 4 is reversed at predetermined time intervals to form a magnetization reversal pattern on the FD. And record the data. At this time, the magnetic material magnetizes the FD applied with a predetermined magnetic pole and thickness, and the thickness of the magnetized magnetic material changes depending on the recording magnetic field generated from the recording / reproducing gap 4. The magnetic material can be deeply magnetized, and the magnetic material can be saturated. For this purpose, a method of increasing the recording / reproducing gap length is employed.

There are three types of FDs on which data is recorded by the 4 MB FDD magnetic head device, and 1 MB FD (5.84 μm to 19.84 μm) according to the wavelength range for recording and reproduction.
m), 2MBFD (2.92 μm to 9.92 μm), 4
MBFD (1.46 μm to 4.96 μm) is present. The 4MB FDD magnetic head records and reproduces all these wavelengths in one recording / reproducing gap, and corresponding to each FD, unformats 1MB by MFM recording method.
Data having a storage capacity of 2 MB or 4 MB is recorded and reproduced at a soft error rate of 10 ^-9 or less. At the same time, 1MBFD recorded by the 4MBFDD magnetic head is reproduced by 1MBFDD, 2MBFDD and other 4MBFDDs that do not record the data, and 2MBFD recorded by the 4MBFDD magnetic head device does not record 2MBFDD and other data. 4MB FDD reproduced by 4MB FDD and recorded by 4MB FDD magnetic head
D is reproduced on another 4 MB FDD in which the data is not recorded, and satisfies the soft error rate of 10 ^-9 or less.

The combination example in which the error rate is most difficult to secure is 1 MBFD recorded by 4 MBFDD to 1 MBFD.
D is the time to play. In order to ensure a soft error rate of 10 ^-9 , it is necessary that the reproduction output at this time be above a certain limit value and the reproduction resolution be within a certain range. At this time, 1 MBFD recorded by a magnetic head having a recording / reproducing gap length of 0.45 μm or more and 0.55 μm or less is reproduced by a 1 MBFDD magnetic head having a recording / reproducing gap length of about 1.2 μm. The relationship among the reproduction output e, the recording / reproducing gap length g, the relative speed v between the FD and the magnetic head, and the magnetization amount φ recorded on the FD is expressed by equation (2).

[0018]

(Equation 2)

In order to increase the reproduction output e in the equation (2), the recording / reproducing gap length of the magnetic head to be reproduced may be reduced. However, the gap length of the magnetic head for 1MBFDD has already been commercialized and shipped. It cannot be changed. v cannot be changed because it is standardized in the 3.5-inch FDD. In the remaining, e can be increased by increasing φ. This can be realized by increasing the recording / reproducing gap length.

In the MFM recording method, the reproduction output ratio between the data patterns “FF” (h) and “AA” (h) is called resolution, and the magnetization amount φ _FF and “A
It is good to increase φ _FF in the magnetization amount φ _AA at the time of the A ″ pattern recording, but if the value of φ _FF / φ _AA does not exist within a certain range, it becomes difficult to secure the soft error rate 10 ^−9. In this case, it is difficult to suppress the upper limit of the value of φ _FF / φ _AA , which can also be realized by enlarging the recording / reproducing gap length. .46 μm
Since a short wavelength of up to 4.96 μm must be recorded and reproduced and a 4 MB storage capacity must be recorded and reproduced at a soft error rate of 10 ⁻⁹ or less, the gap length g is determined by the expression (2) along with the condition of the expression (1). It is desirable that the gap be as small as possible, and the optimum range for the read / write gap length of the magnetic head for 4 MB FDD is 0.45 μm.
m and 0.55 μm or less. This optimum range is shown in FIG.

In order to obtain the recording / reproducing gap length, it is difficult to increase the gap length unless the reproducing efficiency of the magnetic head is excellent when recording and reproducing data in the 4 MB mode, that is, 4 MBFDD. By increasing the recording / reproducing gap length, 1.46 μm to 4.9
This is because φ _FF / φ _AA sharply decreases in recording / reproducing a short wavelength of 6 μm. This is because φ _FF decreases and the reproduction output e itself when reproducing the magnetization amount of φ _FF decreases due to the increase in the gap length g. In the magnetic head device according to the present invention, the reproduction efficiency of the entire magnetic head is increased by the structure in which the first magnetic core 1 is not provided with the magnetic separation layer.

Embodiment 2 FIG. In the above embodiment, the magnetic separation layer is not provided on the first magnetic core 1, but may be provided. However, in this case, the range of the optimum gap length is smaller than that of the magnetic head having no separation layer. Get caught. Further, the present invention can be applied to a structure in which a magnetic material having a higher saturation efficiency density than the magnetic core is interposed on the mating surface between the first magnetic core and the second magnetic core.

[0023]

As described above, according to the present invention, backward compatibility can be satisfied by limiting the range of the gap length to 0.45 μm or more and 0.55 μm or less, and 4 MB can be satisfied.
There is an effect that the performance of the magnetic head device mounted on the FDD is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a magnetic head device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of a recording / reproducing gap portion of the magnetic head device according to one embodiment of the present invention.

FIG. 3 is a perspective view showing an example of a conventional magnetic head device.

FIG. 4 is a diagram showing a range of a recording / reproducing gap length of a magnetic head device according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first magnetic core 2 second magnetic core 3 third magnetic core 4 recording / reproducing gap 5 erasing gap 6 recording / reproducing gap length 7 recording / reproducing coil 8 erasing coil

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 5/23 G11B 5/127 G11B 5/187 G11B 5/265

Claims (3)

(57) [Claims] 1. A storage capacity of at least 4 megabytes can be recorded and reproduced by an MFM recording method.
2 megabytes, the magnetic head device mounted 1.6 megabytes or 1 megabyte 3.5-inch floppy disk drive capable of recording and reproducing the storage capacity of the read-write gap length required for recording and reproducing data 0 . A magnetic head device characterized by being formed in a range of 45 μm or more and 0.55 μm or less. 2. A first method for forming a read / write gap.
2. The magnetic head device according to claim 1, wherein a magnetic material having a higher saturation magnetic flux density than the magnetic core is interposed on the abutting surface between the magnetic core and the second magnetic core. 3. A magnetic circuit having two gaps of recording / reproducing and erasing, a magnetic circuit being closed by a magnetic circuit by a back core, and a magnetic core sandwiched between the two gaps having an integrated structure without a magnetic separation layer. 3. The magnetic head device according to claim 1 or claim 2.