JPH0364956B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to magnetic storage devices such as magnetic disks or magnetic drums. The surface of a continuous thin film magnetic memory is finished to be extremely smooth in order to allow the magnetic head to move as close as possible to recording and reproducing information in order to perform high-density recording. Using such a magnetic memory, the magnetic head and the surface of the magnetic memory are set in contact at the start of operation, and by applying the required rotation to the magnetic memory, the distance between the magnetic head and the surface of the magnetic memory is created. It has become clear that the following problems occur when operating the so-called contact start-stop method, in which an air space is created in this state and recording and playback are performed in this state. When the magnetic storage body is stopped, the magnetic head is in contact with the surface of the magnetic storage body, but at this time, the close contact between the magnetic head and the magnetic storage body is strong, and an excessive force is applied to the magnetic head when the operation starts. Accidents may occur, such as the magnetic head being destroyed by the magnetic head, or the magnetic head bouncing on the surface of the magnetic storage medium, causing damage to the magnetic storage medium. Also, during operation, the magnetic head may collide with the magnetic storage body, or the flying becomes unstable, especially immediately after the start of rotation or just before stopping when the levitation force of the magnetic head becomes weak, causing the magnetic head to collide with the magnetic storage body. Accidents may occur. Furthermore, during operation, discharge may occur between the magnetic head and the magnetic storage body, which may generate noise and cause malfunctions during recording and reproduction. This phenomenon is noticeable in continuous thin-film magnetic storage materials that use magnetic metals or ferrite as storage media, but is less of a problem in so-called coated disks, in which magnetic powder is dispersed and coated in a binder. . This is thought to be due to the fact that in the former case, the surface of the magnetic storage body is extremely smooth and the distance between the magnetic head and the magnetic storage body is small. The present invention aims to solve such problems in magnetic storage devices using continuous thin-film magnetic storage bodies, and is directed to a magnetic storage body attached to a rotating shaft and its rotating magnetic field. A magnetic storage device characterized in that a static eliminator is further housed in a container housing a magnetic head that is provided close to the surface of the magnetic storage body and records and reproduces information on the magnetic storage body. It is. The static electricity eliminator used in the present invention includes a type that blows ionized air and a self-discharge type. As a specific example of the former, US Scientific
Enterprises' products include ``air guns,'' ``ionized air blowers,'' and ``ultrasonic ionized cleaners.''
One example is one sold by Huyuguru Electronics Co., Ltd. When using this type of static electricity remover, the static electricity remover 3 may be installed in the container 1 facing the magnetic memory 2 as shown in FIG. In FIG. 1, 4 is a rotating shaft to which the magnetic storage body 2 is attached and rotated;
is the magnetic head, and the wavy arrow is ionized air. Examples of the latter type of static eliminator, that is, a self-discharge type static eliminator, are "ES Cleaner", a product of Nippon Kayaku Co., Ltd. and sold by Nakatani Co., Ltd., and a product of Shishido Shokai Co., Ltd. Examples include "eliminostat". The principle of this type of static electricity removal is that high-voltage alternating current is passed through the electrodes to cause ionization by corona discharge, which neutralizes and removes the charged charges, and also removes the charged charges by causing direct leakage by bringing the electrodes into contact. This is considered to be the case. When using this type of static electricity remover, as shown in FIG. 2, a brush-like electrode 6 with soft bristles made of metal fibers or carbon fibers is provided so that the bristles are in contact with the surface of the magnetic memory 2. . Although the number of electrodes 6 is one in FIG. 2, it is possible to provide as many electrodes as necessary depending on the number of magnetic storage bodies accommodated. Continuous thin film magnetic storage bodies used in the present invention include those that use a metal magnetic thin film as a storage medium and those that use a ferrite thin film as a storage medium. In the former case, an underlayer with a thickness of several tens of μm is provided on the substrate, a metal magnetic medium layer with a thickness of 0.03 to 0.1 μm is coated on top of the base layer, and a layer with a thickness of
A structure coated with a protective film of 0.01 to 0.3 μm, or an additional thickness between the metal magnetic layer and the protective film of the structure
It has a structure in which a nonmagnetic alloy layer of about 0.02 μm is provided. As the substrate, a titanium alloy or a lightweight aluminum alloy with good workability is used for machining by lathe processing and thermal straightening so that the surface roughness is 50 μm or less in the circumferential direction and 100 μm or less in the radial direction. The base layer is provided to obtain a smooth surface, and is coated with Ni-P alloy or the like by plating.
The surface is mechanically polished to a maximum surface roughness of about 0.03 μm. The metal magnetic media layer is Co,
Typical alloys containing Ni or Fe include
Co-Ni-P, Co-Mn-P, Co-W-P, Co-
There are Cr, etc., and these are formed by a plating method, a vapor deposition method, a sputtering method, or an ion plating method. As a protective film, silicic acid polymer (polysilicic acid),
Silicon compounds such as glass and other silicon oxides or silicon nitrides, highly hard and corrosion-resistant non-magnetic metals such as Rh or Cr, or their alloys, or Al, Co, Ni, Cr, Ti, Zr or Ce or their A cured alloy formed by a coating method, a vapor deposition method, or a sputtering method is used. Further, the nonmagnetic alloy layer is provided to improve the adhesion between the metal magnetic medium layer and the protective film thereon, and is preferably Ni-P. The latter of continuous thin film magnetic storage bodies, that is, those that use a ferrite thin film as a storage medium,
Some have a structure in which a ferrite film is coated on an aluminum alloy substrate having an alumite coating. The alumite coating has a thickness of several μm and has a rough surface.
It is mirror polished to about 0.02μm.
Ferrite films are formed using known manufacturing techniques such as reactive sputtering, reactive vapor deposition, and chemical precipitation. This ferrite film is basically Fe ₃ O ₄ , but it may be mixed with Co to improve its magnetic properties or oxidized to an intermediate state with γ-Fe ₂ O ₃ . be. The appropriate thickness of the ferrite film is 0.1 to 0.25 μm. Some recording media using ferrite have a structure in which a mirror-polished glass substrate is coated with a ferrite film. These recording media using ferrite do not require a protective film because ferrite has high mechanical strength. The magnetic head used in the present invention is a floating type head, and a typical magnetic head is embedded in a slider with a floating surface formed in an inclined plane shape or a cylindrical shape using a glass adhesive. The slider is gimbally supported by a thin leaf spring so as to be able to swing back and forth and left and right, and is attached to a head arm via this, and is pressed toward the surface of the magnetic storage body by a leaf spring at the base of the head arm. In the present invention configured in this way, the static electricity eliminator removes the electrical charge generated on the magnetic head and the magnetic storage body due to their relative movement during operation of the storage device, thereby preventing collision between them. It acts to prevent the generation of noise due to discharge between the two. Furthermore, by preventing charging, the adhesion strength between the magnetic head and the magnetic storage body is weakened when the rotation of the magnetic storage body is stopped, thereby reducing the occurrence of accidents at the start of operation. Next, the present invention will be explained in more detail with reference to Examples. The table shows the measurement results of the tangential friction force at a humidity of 30% and a temperature of 25° C. when a static electricity eliminator was installed (example) and when it was not installed (comparative example). Tangential friction force refers to the force of tangential friction when a magnetic head is placed in close contact with the surface of a magnetic disk attached to an air spindle with radius r, at a distance of R from the center, and a string wound around the air spindle is pulled. Letting f be the force exerted on the thread when it is rotated to break off its close contact with the magnetic head, the tangential frictional force F is determined as F=r/Rf. In the table, self-discharge type in the static electricity eliminator column refers to the case where the above-mentioned self-discharge type static electricity eliminator is installed, and ionization refers to the case where the above-mentioned static electricity eliminator that blows ionized air is installed. It shows. The magnetic disks of Example 1 and Comparative Example 1 were constructed using a Ni-P alloy as a base layer on a disk-shaped substrate made of an aluminum alloy processed to have a surface roughness of 50 μm or less in the circumferential direction and 10 μm or less in the radial direction. is plated to a thickness of approximately 50 μm, and the maximum surface roughness is
Co is coated as a metal magnetic medium layer on top of a mirror-polished material with a thickness of 30 μm and a thickness of 0.02 μm.
Ni-P alloy was plated to a thickness of 0.05 μm, and then an isopropyl alcohol solution containing 2% by weight of tetrahydroxysilane was applied by spin coating. After drying,
It is coated with a polysilicate protective film by baking for a period of time. In the magnetic disks of Example 2 and Comparative Example 2, the protective film of Example 1 was replaced with a sputtered SiO ₂ film. The magnetic disks of Example 3 and Comparative Example 3 were
Instead of coating the metal magnetic media layer with a separate protective film as in the example, the surface of the metal magnetic media layer in Example 1 was oxidized to form Co-Ni oxide, which was used as the protective film. It is something. The magnetic disks of Example 4 and Comparative Example 4 were mirror-polished to a surface roughness of approximately 0.02 μm.
A thin ferrite film with a thickness of 0.2 μm was coated on an aluminum alloy substrate having an alumite coating with a thickness of 0.2 μm using a reactive sputtering method.

【table】

[Table] The table shows that the tangential friction force is around 10g when a static electricity eliminator is not used, which is compared to Comparative Example 1.
Although there is no significant change even if a lubricating layer is formed as shown in the figure, when a static electricity eliminator is used, the static electricity decreases to around 1 g. It has been shown to be extremely effective. Further, the incidence of collision between the magnetic head and the surface of the magnetic storage body was approximately 1% in the comparative example, but almost no collision occurred in the example. Further, while the variation in reproduction output value was 5 to 10% in the comparative example, it was reduced to 2 to 3% in the example. In addition, the frictional noise at the start and end of device operation was reduced, and the discharge noise during recording and playback was also eliminated.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are schematic diagrams each showing an embodiment of the present invention. 1... Container, 2... Magnetic memory, 3... Static eliminator that blows ionized air, 4... Rotating shaft, 5... Magnetic head, 6... Electrode of self-discharge type static eliminator.

Claims (1)

[Scope of Claims] 1. A magnetic storage body attached to a rotating shaft, which contacts the surface of the magnetic storage body when the magnetic storage body is stopped, and which moves away from the surface and transfers information to the magnetic storage body when the magnetic storage body is in a rotating state. In a magnetic storage device in which a magnetic head for recording and reproducing is housed in a sealed container, a static electricity remover is further housed in the container, and the static electricity remover removes the magnetic head from the magnetic storage body. Preventing collision between the magnetic head and the magnetic storage body by removing electrical charges generated therein due to relative motion, and preventing noise caused by discharge between them, Furthermore, the magnetic storage device is characterized in that the adhesion strength between the magnetic head and the magnetic storage body is weakened when the rotation of the magnetic storage body is stopped. 2. The magnetic storage device according to claim 1, wherein the static electricity eliminator is capable of supplying ionized air. 3. The magnetic storage device according to claim 1, wherein the static electricity remover is a self-discharge type static electricity remover.