JPH01182964A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the durability of a system and to simultaneously improve the stability of a recording and reproducing characteristic by arranging a regulation pad in the vicinity of an abutting point to the disk of a magnetic head and effectively controlling a disk surface deflection at the abutting point. CONSTITUTION:A magnetic head 23 and supporting pads 32 and 33 are arranged at the both sides of a disk 10 so that the supporting pad can support the surrounding of the abutting point to the disk 10 of the magnetic head 23 and a recording and reproducing is executed by pressing the magnetic head 23 against the disk 10. Regulation pads 24 and 25 of which tip steps back than the magnetic head regulating the surface deflection width of the disk 10 with the supporting pad tip are provided at a position closer to the magnetic head than the supporting pads 32 and 33 of the front and the rear of the rotation direction of the magnetic head 23. Thus, a head assembly excellent in the durability and the stability per head can be provided.

Description

[Detailed Description of the Invention] [Field of Application] The present invention relates to a magnetic disk device that uses a disk body made of a flexible thin-film magnetic recording medium, and more specifically, to a magnetic disk device that uses a disk body made of a flexible thin-film magnetic recording medium, and more specifically, a magnetic disk device that performs recording and reproduction by bringing a magnetic head into contact with the disk body. Related to magnetic disk devices.

[Prior Art] Magnetic disk devices using flexible magnetic recording media are well known as floppy disks and microdisks.
It is widely used as an auxiliary storage device for computers.

In recent years, the demand for high-density recording has become higher and higher.
Instead of the conventional coated magnetic recording media that uses a binder in the disk body, there are those that use a ferromagnetic metal thin film for the magnetic recording layer, as well as Japanese Patent Publications No. 1981-91 and Japanese Patent Application Laid-open No. 1981-5.
It has been proposed to use a thin film type magnetic recording medium with a recording layer made of a metal thin film, such as one using a cobalt alloy thin film having perpendicular magnetic anisotropy, as disclosed in Japanese Patent No. 404. However, when such a metal thin film is used as the magnetic recording layer,
Since the frictional resistance with the magnetic head is large, it is susceptible to wear and damage and lacks durability.

On the other hand, the present inventors have previously proposed
In Japanese Patent No. 58, a magnetic disk device was proposed in which the area around the contact point of a magnetic head to a disk is supported by a pad.

Although this magnetic disk device overcomes the above-mentioned difficulties and realizes stable recording/reproducing characteristics and durability close to the level of practical use, further improvement in durability is required for practical use.

[Object of the invention] The present invention was made in view of the current situation, and is disclosed in Japanese Patent Application Laid-open No. 6
Regarding the improvement of the magnetic disk device disclosed in Japanese Patent No. 2-279558, the object of the present invention is to provide a magnetic disk device equipped with a head assembly having excellent durability and stability per head.

[Structure and operation of the invention] The above objects are achieved by the invention as follows.

That is, in the present invention, a magnetic head and support pads are arranged on both sides of a disk made of a flexible thin-film magnetic recording medium such that the support pads support the area around the point of contact of the magnetic head with the disk. In a magnetic disk device in which a magnetic head is pressed against a disk for recording and reproduction, the disk is placed between the tip of the support pad and the magnetic head at a position closer to the magnetic head than the support pads at the front and back of the magnetic head in the direction of rotation of the disk. This magnetic disk device is characterized in that it is provided with a regulating pad whose tip is set back from the tip of the magnetic head, which regulates the surface runout width of the magnetic head.

The present invention uses a metal thin film in the recording layer, specifically Co-C as described below.
While investigating various thin-film flexible disks and head assemblies using perpendicular magnetization films, it was discovered that the disk itself exhibits a kind of spring-like property, and as a result of various studies to take advantage of this property, it was found that scratches on the medium and head could be prevented. This was accomplished by coming up with the above-mentioned new head assembly that is less likely to cause this and has good head contact.

As mentioned above, the basic configuration of the present invention differs from the conventional device in which the disk is held between a head and a pad that are arranged opposite to each other, and the disk is regarded as a leaf spring, and the disk is supported at both ends by support pads. Since the disk is configured to record and play while supporting the magnetic head, the contact between the magnetic head and the disk is flexible and extremely stable. At the same time, there are regulating pads on the inside of the support pad at the front and back of the head to regulate the surface fluctuation of the disk, that is, vertical fluctuations, so even if there is surface runout of the disk, these regulating pads placed near the head can prevent the surface from moving. Since vibration can be reduced, fluctuations in impact force when the head and disk slide can be reduced, making it possible to further improve durability and reliability. Furthermore, as is clear from the above configuration, since the disk is not sandwiched between the magnetic head and the pad from both sides, but only touches one side of the disk at a different position, this is advantageous in terms of heat, foreign matter, and abrasion. Durability is further improved. Moreover, the entire head section is also compact. That is,
Through these synergistic effects, a disk device with practical levels of reliability and durability, which was previously impossible, can be realized.

From the above point, any thin film magnetic recording medium of the present invention can be used as long as it has flexibility to act as a leaf spring. Such thin-film magnetic recording media include Fe as a recording layer on a flexible substrate such as an organic polymer film such as polyethylene terephthalate, polyethylene naphthalate, or polyimide.

Examples include a thin film of a ferromagnetic metal such as Co or Ni, and a protective layer provided thereon. Among them, NiFe is used on the flexible substrate, which is attracting attention from the viewpoint of high-density recording surfaces.

CoTa, Co1r, CoZrNb, CoZrT
CoCr, CoCrTa, CoV, C directly with or without a high magnetic permeability layer made of alloy thin film such as a.
It can be advantageously applied to a perpendicular magnetic recording medium provided with a perpendicular magnetic layer made of an alloy thin film such as oQ.

Particularly from the viewpoint of wear resistance, a protective layer made of a non-magnetic metal oxide with high hardness and good wear resistance, such as cobalt oxide, silicon oxide, or copper oxide, is applied on the recording layer at a thickness of 50 to 500%.
A thin-film magnetic recording medium provided with a film thickness of about 100 ml is preferable.

Further, the magnetic head of the present invention is not particularly limited, and all known types such as a ring head and a perpendicular head can be applied. The shape may be any structure as long as it does not concentrate impact force during sliding, and it is preferable that at least the side cross section of the sliding surface with the disk in the rotational direction of the disk is circular. Examples of such heads include the known button type with a spherical sliding surface, and the known VTR (video tape recorder) head type with a cylindrical sliding surface, among others, those with a spherical sliding surface. is preferred. The radius of curvature of the sliding surface must be determined experimentally depending on the disc, but it is usually several mm.
It is in the range of several 100 mm.

Especially 50 kfrpi (flux reversal
per 1 inch (number of magnetic flux reversals per inch), the radius of curvature of the head is 1.
0mm or less and the tip end surface of the head, that is, the sliding movement is 1m
It is preferable that the size is as small as m to several mm square because stable recording and reproduction can be performed.

Furthermore, the material of the sliding movement, that is, the head slider, should be selected depending on the disk, but it is usually ferrite type, glass type, or alumina type ceramic.

Known head slider materials such as potassium titanate, barium titanate, and zirconium oxide are used, but those with good thermal conductivity and high hardness are preferably used in terms of durability.

Both the support pad and the regulation pad of the present invention can support the disk with good sliding characteristics and have strength to withstand sliding.
It is fine as long as it can reliably control the disc surface image.
Therefore, a rigid pad, for example, a configuration similar to one of the moving parts of the magnetic head described above, can be preferably applied. In other words, the shape of the sliding surface may be such that the impact force during sliding does not concentrate. Therefore, it is possible to use a disk whose side cross section in the disk rotation direction is circular or has a flat surface with chamfered edges. The material is preferably a hard material such as a wear-resistant material that has the strength necessary for support, such as the aforementioned head materials such as crystallized glass, alumina ceramics, carbon, etc., or those whose surface has been hardened with titanium nitride, etc. Applicable. Among these hard pads, those with good thermal conductivity and high hardness are more preferably used.

By the way, among the above-mentioned pads, the support pads are discretely arranged so as to support the periphery of the contact point of the magnetic head to the disk at appropriate intervals.

This support pad is provided at least on both sides of the rotational direction of the contact point so that the contact between the magnetic head and the disk is stable.
It is preferable to support it at a point. The spacing between the supporting points is selected depending on the characteristics of the disk used, such as its rigidity. Here, the pad may be independent for each support point as shown in the embodiments described below, or it may be an integral body with predetermined support points formed thereon.

In addition, the regulating pad regulates the surface runout of the disk moving in and out of the magnetic head contact area between it and the tip of the support pad. They are placed inside before and after the magnetic head. In addition, the configuration of the head section is such that the magnetic head can follow the disk surface independently of the regulating pad via a plate spring, etc., as in the embodiment, in order to suppress surface runout and stabilize the head contact. Preferably, the spacing can be set mechanically.

It is preferable to install the above-mentioned support pad and regulation pad together with the magnetic head on a common carriage mechanism in terms of compactness of the head section and stability of recording and reproduction. On the other hand, from the viewpoint of quick response of the head, it is preferable to provide the pad on a fixed part such as the machine stand or the jacket of the disk to reduce the weight of the head part that is moved by the carriage. At this time, it is preferable from the viewpoint of recording/reproducing stability to provide only the regulating pad on the fixed part and to provide the head and support pad on the carriage mechanism. Note that the regulating pads at this time are arranged across the radial direction of the disk in front and behind the head so as to cover the head movement range, that is, the recording area of the disk. Specifically, this configuration may be one in which the above-mentioned flat pads are arranged at appropriate intervals, but it is also possible to arrange pads in the shape of a kamaboko or a button continuously in the radial direction over at least the entire recording area. It is preferable from the viewpoint of stability of head movement.

In the present invention described above, a thin film magnetic recording medium is used in which the disk is provided with a highly hard protective layer such as the aforementioned metal oxide, and the sliding surfaces of the magnetic head and pads are made of a similarly hard material. A system with excellent durability, especially wear resistance, can be realized. In the present invention, since the disk is not held between a magnetic head and a pad as in the conventional device, such a combination of hard surfaces can be realized without any problems. From this point of view, it is preferable that the above-mentioned support pad and regulation pad are high-hardness pads whose sliding movement has a hardness of 500 or more on the Vickers scale.

In the present invention, as described above, the magnetic head and the above-mentioned pad are mounted on a common Herad carriage mechanism and used in the same manner as in conventional floppy disk devices. In this case, the magnetic head and at least one of these pads is supported by a spring, or a shock absorbing material such as rubber or a spring is placed between the arms of the carriage so that the magnetic head is pressed against the disk by the spring, and Preferably, the distance between the tips of the support pad and the regulation pad is maintained at a set distance. This configuration compensates for the difference in the elasticity of each disk to ensure stable disk exchange, and also suppresses surface scratching of the disk at the head contact point and its vicinity to a predetermined value or less, reducing impact with the head. Effects can be obtained.

Further, when recording and reproducing data on both sides of the disk, a configuration may be adopted in which a magnetic head and the above-mentioned pads are arranged on both sides of the disk. In this case, either a method in which the magnetic heads are separated from each other in the direction of rotation of the disk, or a method in which the magnetic heads are separated in the radial direction of the disk as employed in current floppy disk drives can be applied.

As described above, in the present invention, since the regulating pad is arranged near the contact point of the magnetic head to the disk, the disk surface runout at the contact point is effectively suppressed, and an impact load on the magnetic head is prevented. This not only improves the durability of the system including the disk, but also improves the stability of recording and reproducing characteristics. Furthermore, since the regulating pad and the magnetic head are close to each other, the entire head can be constructed compactly, which is advantageous in terms of miniaturization and improved followability.

As described above, the present invention provides a magnetic disk device that has practical level recording and reproducing characteristics and durability using thin-film magnetic recording media, especially perpendicular magnetic recording media whose practical use is long-awaited due to its high-density recording surface. It will be done.

The details of the present invention will be explained below using a perpendicular magnetic recording type magnetic disk device as an example.

Example 1 FIG. 1 is an explanatory diagram of the head portion of the embodiment, and FIG.

FIG. 3 shows the first section that constitutes the head section. FIG. 3 is a plan view of the second carriage part. In the figure, 10 is a disk.

20 indicates a first carriage section, and 30 indicates a second carriage section.

The disk 10 has the same shape as a commercially available 3.5-inch flexible disk, and is made of a perpendicular magnetic recording medium shown in FIG. That is, the surface roughness of the flexible film 11 is 20 in center line average roughness Ra (JIS BO610).
A (measured with phaStep 200 manufactured by TENCORIN5TRUHENTS, USA), film thickness 50μ
A polyethylene terephthalate (PET) film with a thickness of 0.5 μm and a coercive force of approximately 3 Oe was used as high magnetic permeability layers 12A and 12B on both sides of the film.
i A FeHo alloy layer was used as the recording layer 13A, 13B, a CoCr alloy layer with a thickness of 0615 μm, a perpendicular coercive force of 6000 e, and a saturation magnetization of 500 emu/cc was used as the recording layer 13A, 13B, and a CO3 layer with a thickness of 0.02 μm was used as the protective layer 14A, 14B.
04 was formed by a known facing target sputtering method as disclosed in Japanese Patent Application Laid-open No. 57-100627 and Japanese Patent Application Laid-Open No. 57-158380.

The first carriage part 20 is connected to the head 23 via a plate spring 22 on a recess 2ia provided in the center of the head support seat 21.
Roughly speaking, regulating pads 24.25 are provided so as to be located inside the support pads described below before and after the head 23 of the head support seat 21 in the disk rotation direction, and the head 23 is independent of the regulating pads 24.25. It is configured to follow the surface of the disk 10, and is attached to an arm 41 of a carriage mechanism (not shown).

The second carriage part 30 has two support pads 32 and 33 placed on the pad support seat 31 at positions corresponding to the front and rear of the head in the disk rotation direction so as to support the periphery of the contact point of the head 23 with the disk 10. With this configuration, it is attached to the other arm 42 of the carriage mechanism, and is opposed to the first carriage part 20 with the disk 10 interposed therebetween.

The parallelism of the first and second carriage parts 20 and 30 is set at two intervals by the arm 41.
It can be set by an adjustment mechanism (not shown) provided at 42, so that the surface of the disk 10 can be adjusted, the contact of the head 23 with the disk surface can be adjusted, and the distance between the ends of the regulating pads 24.25 and the support pads 32.33 can be adjusted. It has become. The tip of the head 23 provided on the leaf spring 22 is usually provided to protrude by 10 to 100 μm from the tips of the regulating pads 24 and 25. The size of this protrusion is disk 1
It is determined by the balance of the impact forces between the head 23, the support pads 32 and 33, and the disk 10 that come into contact with each other, and the stability of the recording/reproduction signal.

The head 23 is as shown in FIG. 5. A groove 233 is provided at the tip of a ferrite block 231 in which a recording/reproducing coil 232 is provided, and a head slider portion 234 provided with a main magnetic pole 235 is in close contact with the ferrite block 231. A known main pole excitation type perpendicular head with a structure of
As shown in the figure, the sliding movement is 1.9mmWx1.3mm l
(W: track width) rectangle with radius of curvature iom
It is a spherical surface of m. Potassium titanate was used for the slider portion 234.

The support pads 32, 33 and the regulating pads 24, 25 are made of high homogeneous glassy carbon (manufactured by Kao (ltiJ), and are squares of 2 mm x 2 mm and 1.5 mm in height, as shown in Fig. 6.
The ridge of the columnar body P of L) is chamfered, and a flat pad is formed with two grooves of approximately 0.2 mm in diameter to capture wear particles in a direction perpendicular to the direction of rotation of the disk. be.

The regulating pads 24 and 25 were placed 2 mm apart from the head 23 at the front and back of the head 23 on the circumference where the head 23 slides on the disk surface. The support pads 32.33 are
A position on the opposite side to the head 23 and the disk 10, which corresponds to a position on the outside of the regulation pad 4.5 mm apart from the head 23 before and after the head 23 on the serial line between the regulation pad 24 and 25 and the head 23. It was placed in

The disc 10 was originally developed by the inventors in a patent application filed in 1986-1.
75981, the disc regulating material such as a non-woven fabric liner is removed from a commercially available 3.5-inch disc jacket, and a carbon-based sliding plate ( Specifically, we created two regulating ring plates made of Metaloplast (manufactured by Two-Tone), and attached them to a modified jacket in which the regulating ring plates were fixed in such a way that the outer peripheral edge of the disk was sandwiched between a 100 μm gap to prevent disc surface wobbling. I put it away and set it up.

FIG. 7 shows the disk surface runout in this example. The spacing between the tips of the regulating pads 24 and 25 with respect to the support pads 32 and 33 was adjusted so that the maximum amplitude of surface runout was 23 μm at 60 rpm with the head 23 removed, and in this state the wear resistance We conducted a durability test.

Even after 13 million passes, there was no damage to either the pads or the disk surface that slid against them, and it was confirmed that they were at a sufficiently practical level.

Furthermore, a head 23 was installed, and the head 23 was brought into contact with the disk, and the tip of the head 23 and the disk surface were adjusted so that the reproduction envelope signal was uniform, and the durability of the recording and reproduction characteristics was examined. Saturation recording/reproduction was performed at 70 kfrpi, and the signal durability was examined by continuously sliding 4 million buses on the recording track, exceeding the 3 million passes specified by the JIS standard for floppy disks. 40
In a test of 00,000 paths, the signal level drop was within 1 dB, which was good. It was confirmed that it was able to sufficiently clear the JIS standards and was at a sufficiently practical level in this respect as well.

As a comparative example, FIG. 8 shows the surface runout when the same disk under the same conditions was inserted into a commercially available 3.5-inch disk jacket and rotated without a head. The maximum value of the width of the surface image is 10 due to the surface vibration control by the soft liner.
It was 5 μm. When I checked the durability in this state, I found that it was 3.
After 1,000,000 passes, dirt appeared on the disk surface, and after 5,000,000 passes, many scratches appeared on the disk surface.

Embodiment 2 In FIG. 1, the support pads 32, 33 are spaced 9.
5 mm, and the regulating pads 24 and 25 were placed at a spacing of 5 mm, and the rest was the same as in Example 1. The surface of the disk 10 was measured using a photonic sensor KO-3 manufactured by MT1 (USA).
40 type was installed in the insertion part of the head 23 instead of the head 23, and measurements were taken. The disks 10 are 50 μm and 42 μm.

A two-layer medium with a protective layer produced by the same facing target sputtering method as in Example 1 was spun onto both sides of the base of a PET film having a thickness of 36 μm to a diameter of 3.5°.

The disk 10 was attached to the same modified jacket with a regulating ring plate as in Example 1, and the effect of suppressing disk surface runout was tested. The following tests were conducted at a rotational speed of 600 rl) m, and each data was measured at a position with a disk radius of 31 mm.

Under free conditions without both pads, the disk surface area was 58 μm for a 50 μm base and 42 μm for a 142 μm base.

Next, the vibration of the disc was measured with both pads placed in the above-described arrangement. FIG. 9 shows an example of the periodic fluctuation of vibration in the case of a 50 μm base. The maximum image width is 12 μm. FIG. 10 shows the results of analyzing this periodic fluctuation using Fourier transform. The high frequency component is 2001
12 (fundamental wave 10H2), the attenuation is almost 40 dB or more. From this, the regulation pad 24.25
It was found that when the disk 10 rotates, the surface (edge) is easily controlled. The measurement results for the 42 μm and 34 μm bases are almost the same as the measurement results for the 50 μm base shown in FIGS. 9 and 10. Ta.

Next, instead of the photonic sensor, a dummy having a similar shape to the head was inserted, and the force acting on the dummy was measured with a strain gauge, thereby measuring the relationship between the head pushing amount d and the head load W applied to the head.

The results are shown in FIG. Disc surface depth is 20μm
Since it can be regulated as follows, the head push md is 40
By setting the thickness to about .mu.m, the sliding movement between the head and the disk surface becomes uniform around the circumference of the disk.

From Figure 11, when d=40μm, the head load W is 50
Depending on the base thickness of μm, 42 μm, and 36 μm, 5
mN (millinewton), 4 mN, 2.5 mN.

This difference in head load W is caused mainly by fixing the spacing between the support pads 32 and 33 with respect to the bending rigidity of the disk 10. By changing the spacing between the support pads 32 and 33, the head load W can be adjusted.

Since the regulating pads 24, 25 are narrower than the spacing between the supporting pads 32, 33 and are provided near the head 23, the sliding stress between the regulating pads and the disk surface is reduced when the disc slides when the head 23 is pressed. This can be easily seen from the configuration shown in FIG.

The head load W is approximately 2.5 using a 36 μm base medium.
When the recording/reproducing characteristics at mN and 70 kfrpi were investigated, the signal level around the disk became almost flat as shown in FIG. 12, confirming the shake suppressing effect.

It was also confirmed that there were almost no whisker-like instantaneous fluctuations in the signal, and that impact loads on the head were also prevented.

From the above embodiments, the present invention can control disk surface runout, reduce the head load, and achieve stable sliding with the disk, so it is possible to improve signal stability and durability at the same time. I understand.

[Brief explanation of the drawing]

FIG. 1 is a partial side sectional view of an embodiment of the present invention, FIG. 2 is a plan view of the head mounting side, FIG. 3 is a plan view of the pad mounting side, and FIG. 4 is the configuration of the disk used in the embodiment. 5 is a side sectional view showing the structure of the head used in the example, FIG. 6 is a perspective view of the pad of the example, and FIG. 7 is a graph of the surface runout measurement results of Example 1. , FIG. 8 is a graph of the surface runout measurement results of the comparative example, FIG. 9 is a graph of the surface runout measurement results of Example 20, FIG. 10 is a graph of the results of the Fourier analysis of FIG. 9, and FIG. 11 is the graph of the example. FIG. 12 is a graph of the measurement results of the head load W against the pushing amount d in Example 2, and FIG. 12 is a graph of the reproduced signal in Example 2. 10: disk, 23: head. 24.25: Regulation pad, 31.32: Support pad Z
35- No. 71 Old Tea Figure 3 Time (Second) 0 ZO406080+0O(n-'5ec)L
i 〒 Doorshi 1 (unseko) 2nd child 1no, Jino 5th also @'r (Hmi) Oro Ioo IrOoshimutaman, 1 self (mon゛) wealth jfu 72 muyo

Claims (1)

[Claims] 1. A magnetic head and support pads are arranged on both sides of a disk made of a flexible thin-film magnetic recording medium such that the support pads support the periphery of the contact point of the magnetic head with the disk. In a magnetic disk device in which a magnetic head is pressed against a disk for recording/reproduction, a magnetic head is placed between the tip of the support pad at a position closer to the magnetic head than the support pads at the front and rear of the magnetic head in the direction of rotation of the disk. A magnetic disk device comprising a regulating pad whose tip is set back from the tip of a magnetic head for regulating the surface runout width of the disk. 2. The magnetic disk device according to claim 1, wherein the magnetic head, the support pad, and the regulating pad are mounted on a common carriage mechanism. 3. The magnetic head and the regulating pad are arranged on the same carriage arm, the magnetic head is attached to the carriage arm via a spring, and the tip of the sliding surface of the magnetic head is 5 to 100 μm from the tip of the sliding surface of the regulating pad. 3. The magnetic disk device according to claim 2, wherein the magnetic disk device is protruding.