JPH01128231A - Device for orienting magnetic recording medium - Google Patents

Abstract

PURPOSE:To parallel the longitudinal direction of magnetic particles in the circumferential direction of a disk substrate by flattening and broadening the end face including a gap part and providing drying nozzles at the center of the gap part. CONSTITUTION:The disk substrate 3 on which a magnetic coating compd. is spin-coated is rotated at a low speed and the magnetic particles are arranged in the circumferential direction of the substrate 3 over the width nearly equal to the width of the gap part 4. The opposed parts of magnet yokes 1 are formed to an L shape and one end face including the gap 4 is flattened and broadened; therefore, the magnetic fields in reverse directions in the position apart from the gap 4 are decreased and the leakage of the magnetic fluxes in the part parallel with the substrate 3 is eliminated. Drying air is directly blown from the nozzle 5 to the coated film through the gap 4 to dry the magnetic particles in the arranged state. The magnetic particles are thereby arranged in the circumferential direction of the substrate 3 and the magnetic disk having no disturbance in the arrangement by the leakage of the magnetic fluxes is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus for manufacturing a magnetic disk used for longitudinal magnetic recording, and particularly relates to a magnetic disk manufacturing apparatus for use in longitudinal magnetic recording. The present invention relates to an apparatus for orienting magnetic fine particles of a magnetic recording medium, which is used to orient and dry body fine particles in the longitudinal direction.

[Conventional technology]

Conventionally, as an apparatus for performing this type of orientation drying, there is an apparatus that performs natural drying while applying an orientation magnetic field in a small area along the circumferential direction of the disk base.

Devices that perform forced dry air blowing out from the entire inner circumference of the disk base, or external forced blow devices that have dry air blowing ports on the outside of the magnet yoke, have been used.

FIG. 2(a) is a plan view showing the use of the above-mentioned external strong blowing type device as an example of a conventional device. In FIG. 2(a), an electromagnetic magnet formed by a magnet yoke 11 having a gap portion 14 and two coil windings 12 moves (rotates) circumferentially at a predetermined interval. It has become.

In order to orient and dry the magnetic particles, after spin-coding magnetic paint on the disk base 13, the disk base 13 is rotated at low speed and a current is applied to the coil winding 12 to create a strong leakage magnetic field in the gap 14 of the magnet yoke 11. , magnetic yoke] 1, magnetic particles are arranged in the circumferential direction of the disk base 13 over a width approximately equal to the width of the gap portion 14 of the magnetic yoke]1. At that time, dry air is supplied to the magnet yoke 11.
The magnetic fine particles in the magnetic paint are oriented while being blown out from a drying air nozzle 15 provided on the outside of the magnetic paint to dry it.

[Problems to be solved by the invention]

The magnetic disks obtained as described above have already been widely used and can be used for general purposes.

However, it was not particularly suitable for applications where noise was a problem. The same thing can be said for both natural drying type devices and devices for blowing forced drying air from the inner circumference of the disk substrate.

FIG. 2(b) is a diagram showing the magnetic field distribution when using the apparatus shown in FIG. 2(a). There is no problem with the magnetic field strength at the center, but there are areas B and B' that are far from the center. It can be seen that at the position (where the magnet yoke 11 rises apart from the disk base 13), a relatively large magnetic field in the opposite direction exists. On the other hand, when the surface of the magnetic disk was observed using a scanning electron microscope, it was found that the amount of magnetic particles that were not parallel to the disk substrate was about 30 to 35 factors. The above means that at least the main cause of the increase in the magnetic field in the opposite direction that causes noise, that is, the cause of the incomplete orientation of the magnetic particles, has become large enough to cause the magnetic yoke 11 to rise. I know it's there. This can be understood if we consider that at the rising portion of the magnetic yoke, the leakage magnetic field is considerably removed from the circumferential direction of the magnetic disk (as long as it does not deviate from the straight line).

Therefore, the object of the present invention is to generate a magnetic field in the opposite direction over a relatively long range on the surface of the electromagnetic disk passing between the gap between the two magnetic yokes, and while passing through that range. The object of the present invention is to provide an orientation device for a magnetic recording medium that can dry as quickly as possible so as to obtain the drying necessary to fix the orientation of magnetic fine particles.

[Means for solving problems]

In order to achieve the above object, the present invention has two magnetic yokes facing each other over as wide an area as possible.

Moreover, it is designed to accelerate drying in areas where the leakage magnetic field is particularly strong.

That is, according to the present invention, two electromagnetic magnets each consisting of a magnet yoke and a coil winding having a gap are arranged such that at least the gap is opposed to each other with a predetermined distance therebetween, and In an orienting device for a magnetic recording medium equipped with a drying nozzle used to dry applied magnetic paint, the opposing portions of the magnet yoke are L-shaped, and one end surface including the gap portion is flat and wide. Further, the opening of the drying nozzle is oriented such that the drying gas passes through the gap and directly impinges on the applied magnetic paint. A device for orienting a magnetic recording medium is obtained.

〔Example〕

Next, two aspects of the present invention will be explained with reference to the drawings.

FIGS. 1(a) and 1(b) are a front view showing this embodiment and its usage situation, and a graph showing the magnetic field distribution.

The difference between FIG. 1(a) and FIG. 2(a) is the shape of the magnet yoke 1 and the position of the dry air nozzle 5.

In order to orient and dry the magnetic particles, after spin-coding magnetic paint on the disk base 3, the disk base 3 is rotated at low speed, and a current is applied to the coil winding 2 to coat the magnetic yoke 1.
When a strong leakage magnetic field is created in the gap 4 of the magnetic yoke 1, magnetic particles are arranged in the circumferential direction of the disk base 3 over a width approximately equal to the width of the gap 4 of the magnet yoke 1. At this time.

The magnet yoke 1 of this embodiment is made of pure iron material with high magnetic permeability, and has two constituent parts arranged opposite each other in an abbreviated shape to form a gap part 4 that causes leakage of magnetic flux. The entire lower surface group including the gap portion 4 is formed flat and wide.

The magnetic field in the opposite direction at the locations indicated by A and A' that are away from the gap portion 4 is smaller than that at B and B' in FIG. 2(a).

The magnetic field distribution between A, A' and the center is shown in Figure 1(b).
They are as shown in C and C'.

This magnetic field distribution is because there is no leakage of the magnetic field in the portion parallel to the disk base 3, compared to the magnetic field distribution of the conventional electromagnetic magnet shown in FIG. 2(b).

When dry air is blown out from the nozzle 5 at the same time as the current is applied to the coil winding 2 or after a slight delay, the nozzle passes through the gap 4 and hits the magnetic paint directly. Since the magnetic paint dries immediately after being arranged in the circumferential direction of the disk substrate 3, the magnetic particles are optimally arranged in the circumferential direction of the disk substrate 3 even when the disk substrate 3 is rotating, and A state is obtained in which the arrangement of the magnetic particles is not disturbed due to leakage of magnetic flux in the portion parallel to the base body 3.

Note that the area of the flat and wide portions indicated by C and C' of the magnet yoke 1 in FIG. 1(a) is preferably one-eighth or more of the surface area of the disk base 30 to be manufactured. Further, in the case of the conventional device shown in FIG. 2(b), there are no flat portions as shown by c and c'.

Furthermore, the electromagnetic magnet of the conventional example and the electromagnetic magnet of this example were used with magnetic paints having the same composition.

When the surface of a magnetic disk manufactured using each of the above-mentioned drying methods at the same magnetic field strength was observed using a scanning electron microscope, it was found that the amount of magnetic particles that were not parallel to the disk base 3 was different from that in the case of the conventional inner periphery drying method using a magnet. Whereas the ratio reached 35 to 40 ratios, in the case of the second invention, it was reduced to about 20 ratios, about half.

〔Effect of the invention〕

As explained above, the present invention provides two
Magnetic yoke of pieces with abbreviated shape.

By using an electromagnetic magnet whose one end face including the gap part is flat and wide, and a drying nozzle provided at the center of the gear part, the longitudinal direction of the magnetic fine particles applied to the surface of the disk base is aligned with the circumference of the disk base. This has the effect of being able to match the directions parallel to each other.

[Brief explanation of the drawing]

Figure 1 ”= ・,, ==,(,
) and (b) are a front view showing this example and its usage situation, a graph showing the magnetic field distribution, and FIGS. 1(a) and (b).
) is a front view showing an example of a conventional electromagnetic magnet and its usage status, and a graph showing the magnetic field distribution. Symbol explanation: 1, 11...Magnetic yoke, 2゜1
2... Coil winding, 3.13... Disk base (non-magnetic magnetic disk base), 4. , 14... gap part. 5.15...Dry air nozzle, A, A,',
B, B'...Position showing wet dog of reverse direction magnetic field, c
, c'...Magnetic field component in the circumferential direction of the nonmagnetic magnetic disk base. Agent (7783) Patent Attorney Noriyasu Ikeda Figure 2 (b) Stone string field strength (b) Magnetic field reached

Claims (1)

[Claims] 1. Two electromagnetic magnets each having a coil winding attached to a magnetic yoke having a gap portion are arranged so that at least the gap portion faces each other with a predetermined interval, and the electromagnets are coated on the surface of the sample to be treated. In a magnetic recording medium orientation apparatus equipped with a drying nozzle used for drying magnetic paint, the opposing portions of the magnetic yoke are L.
The drying nozzle is shaped like a letter and one end surface including the gap part is flat and wide, and the opening of the drying nozzle directs the drying gas through the gap part so as to directly hit the applied magnetic paint. An apparatus for orienting a magnetic recording medium, characterized in that: