JPS61145729A - Orientation device of magnetic field for hard disk - Google Patents

Abstract

PURPOSE:To attain the orientation properties equivalent to that of a magnetic field orientation device aiming at a high degree of orientation with a more complicated structure, by securing such a structure that can move independently a magnetic field generator having a gap for production of a leakage magnetic flux, away from an orientation working position. CONSTITUTION:When an orientation magnet 3 is set close to an orientation working position (close to a substrate), an intensive magnetic field vertical to the substrate surface is produced between the N pole of an orientation magnet 2 and the S pole of the magnet 3. This intensive magnetic field sets the needle-shaped magnetic powder 12 contained in a film 11 on the substrate 1 in the direction vertical to the substrate surface. When the magnet 3 is set apart from the substrate 1, just a weak magnetic field is produced between the N pole of the magnet 2 and the S pole of the magnet 3 since the distance is large between both counter poles. While an intensive magnetic field is produced between gaps of the magnet 2. Thus a magnetic field which is horizontal to the substrate surface and parallel to the revolving direction is produced on the substrate 1. The magnetic field powder 12 in the film on the substrate is orientated in parallel to the substrate surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic field orientation device for a hard disk that magnetically orients magnetic powder in a magnetic coating film applied to a magnetic disk.

2. Description of the Related Art A magnetic disk used as a recording medium in a magnetic disk drive is made by coating an ultra-smooth substrate made of aluminum or the like with a paint containing magnetic powder by a spin code method. Acicular r -Fe2O3 is often used as magnetic powder, but it is well known that output, noise, etc. vary depending on the particle shape and orientation of this magnetic powder. Generally, the coating film is passed through a magnetic field before drying to align the directions of the easy magnetization axes of the magnetic powder.

An example of a conventional hard disk magnetic field orientation device will be described below with reference to the drawings.

Figure 3 (A), (B) and Figure 4 (A), (
Bl is an example of a conventional orientation device. The device shown in Figure 3 is
Applying a horizontal magnetic field to the coating surface 7 using an orientation magnet 41,
This magnetic field causes the magnetic powder in the coating film to be oriented in the circumferential direction. The apparatus shown in Fig. 4 uses a magnetic field that is perpendicular to the coating surface 7 from 42 vertical orientation magnets and a horizontal magnetic field to the coating surface 7 from 41 horizontal orientation magnets to be applied alternately. The idea is to orient it to

Problems to be Solved by the Invention However, in the case of the configuration of the conventional example as described above, the third problem
The device shown in the figure has the problem that sufficient orientation cannot be obtained, and the device shown in FIG. 4 has problems such as being complicated and expensive, and making it difficult to adjust the magnet spacing.

In view of the above-mentioned problems, the present invention provides a hard disk that can realize high orientation while having a simple device structure. a magnetic field generating device having a gap capable of generating leakage magnetic flux parallel to the substrate rotation direction; and a magnetic field generating device having one pole facing one of the poles of the magnetic field generating device across the substrate. of the two magnetic field generating devices, the magnetic field generating device has a gap capable of generating at least leakage magnetic flux, and is located opposite to one pole of the magnetic field generating device with a substrate in between, and has a polarity different from the magnetic pole. The structure is such that a magnetic field generating device having one pole facing each other can be independently moved away from the alignment operating position.

Effect of the present invention With the above-described configuration, one of the magnetic field generators can be gradually moved away from the substrate during the magnetic field alignment process, and before the magnetic field generator is moved away, the magnetic field is applied perpendicular to the substrate surface, and then moved away from the substrate. After that, a magnetic field parallel to the substrate surface can be generated. This allows the horizontal magnetic field and the vertical magnetic field to be switched arbitrarily, making it possible to improve the orientation of the coating film. Furthermore, since the magnetic field generator is located at one location, the structure is simple, and the magnetic pole gap can be easily adjusted.

Embodiment Hereinafter, a hard disk magnetic field orientation device according to an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1(M) and 1(B) are simplified diagrams of a magnetic field orientation device for a hard disk according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a substrate coated with a coating film, which rotates around a rotating shaft 6. As shown in FIG. 2 is a fixed orientation magnet having a gap capable of generating leakage magnetic flux, and 3 is an orientation magnet with one pole facing the substrate and movable up and down.

The operation of the hard disk magnetic field orientation device configured as described above will be described below with reference to FIGS. 2(M) and 2(B).

First, FIG. 2(m) shows the state when the orientation magnet 3 is installed at the orientation operation position (near the substrate). In this case, a strong magnetic field perpendicular to the substrate surface appears between Nli of the orientation magnet 2 and SFM of the orientation magnet 3.

This magnetic field directs the acicular magnetic powder 12 in the coating film 11 on the substrate 1 perpendicularly to the substrate surface. FIG. 2(B) shows a state in which the redistribution inner magnet 3 is separated from the substrate. At this time, since the opposite poles are far apart, only a weak magnetic field is generated between the N pole of orientation magnet 2 and the S pole of orientation magnet 3, and the magnetic field generated between the gap between magnets 2 This causes a magnetic field on the substrate 1 that is horizontal to the substrate surface and parallel to the rotation direction. Due to this magnetic field, the acicular magnetic powder 12 in the coating film 11 on the substrate 1 is oriented parallel to the substrate surface as shown in FIG. 2(B) from the oriented state shown in FIG. 2(A). Ru.

Once the magnetic powder is oriented in the vertical direction, its direction is aligned to some extent, so when it is oriented in the horizontal direction, it is easily oriented and the orientation can be improved.

Table 1 shows a comparison of the magnetic properties of samples produced using the magnetic field orientation apparatus of the present invention with comparative samples produced using a conventional apparatus. The same magnetic paint was used, and the applied parallel magnetic field was 2000 mL at the coating area in both orientation devices.
0e, and the substrate rotation speed was 12Or, p, m, and the sample was prepared.

As can be seen from Table 1, the sample obtained by the apparatus of the present invention was
Comparative Example 1 using the conventional apparatus shown in FIG. 3 also shows a high squareness ratio, and shows a squareness ratio equivalent to Comparative Example 2 using the conventional apparatus shown in FIG.

That is, by using the apparatus of the present invention, it is possible to obtain magnetic orientation equivalent to that of the orientation apparatus shown in FIG. 4, which aims at a high degree of orientation.

As described in detail in Table 1, the hard disk magnetic field alignment device of the present invention includes a magnetic field generating device that faces the substrate and has a gap capable of generating leakage magnetic flux parallel to the direction of rotation of the substrate; and a magnetic field generating device with one pole facing one of the poles of the magnetic field generating device at a position opposite to one of the poles of the magnetic field generating device, and of the two magnetic field generating devices, at least a gap that generates leakage magnetic flux is provided. A magnetic field generating device having a structure in which a magnetic field generating device having one pole opposite to the magnetic pole with a substrate sandwiched therebetween and having one pole opposite to the magnetic pole facing the magnetic field generator can be independently moved away from the alignment operation position. Although it has a simple structure, it can achieve the same orientation as a magnetic field orientation device that aims for a high degree of orientation with a more complicated structure. This makes it possible to realize the following.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram of an embodiment of the hard disk magnetic field orientation device of the present invention, FIG. 2 is a diagram of the operating principle of the device in FIG. 1, and FIG.
The figure is a simplified diagram of a first example of a conventional magnetic field orientation device for a hard disk, and FIG. 4 is a simplified diagram of a second example of a conventional magnetic field orientation device for a hard disk. 1...Substrate, 2,3...Orienting magnet,
6...Rotation axis, 7...Coating surface, 11.
... Coating film, 12 ... Magnetic powder, 13 ...
... Magnetic field, 41 ... Horizontal orientation magnet, 42
...Magnet for vertical alignment. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 (8)

Claims (1)

[Claims] A magnetic field generating device facing the substrate and having a gap capable of generating leakage magnetic flux parallel to the direction of rotation of the substrate, and one pole facing the substrate at a position opposite to one of the poles of the magnetic field generating device. and a magnetic field generating device, which is located at a position opposite to one pole of the magnetic field generating device having a gap capable of generating at least leakage magnetic flux among the two magnetic field generating devices, with the substrate sandwiched therebetween. 1. A magnetic field orientation device for a hard disk drive, characterized in that a magnetic field generation device in which two poles having different polarities are opposed to each other can be independently moved away from an orientation operation position.