JPH10112026A - Production of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and adequately adjust a bead condition, etc., without depending on the operator's degree of skill. SOLUTION: In the process for producing a magnetic recording medium by holding a traveling nonmagnetic base 4 by means of a gravure roll 16 adhered with a magnetic coating material and a back roll 18 facing this gravure roll 16 and applying this magnetic coating material on the base 4, paper P is arranged near the contact part of the gravure roll 16 and the base 4 and the splashed magnetic coating material is adhered to the paper P. The supply rate of the magnetic coating material to the gravure roll 16 is adjusted in accordance with the amt. of the magnetic coating material adhered to the paper P.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium, and more particularly to a method for managing dropout of a magnetic material.

[0002]

2. Description of the Related Art A conventional method for manufacturing a magnetic recording medium will be described with reference to the drawings. FIG. 3 is a schematic diagram showing a step of applying a magnetic paint in the manufacture of a magnetic recording medium, and FIG. 4 is a configuration diagram of a coating apparatus used in the coating step of FIG. In general, magnetic recording media such as audio tapes and video tapes are obtained by dispersing and kneading a ferromagnetic material, a binder, a lubricant and the like in an organic solvent on the surface of a long support having a fixed width such as a polyester film. It is manufactured by forming a magnetic layer by applying a magnetic paint.

In applying the magnetic coating material to the support, as shown in FIG. 3, a raw support 4 wound in a roll shape around a supply roll 2 is passed through a roller such as a pinch roller 6 to a predetermined height. The support 4 is guided to a coating device 8, and a magnetic paint is applied to one surface of the support 4 over substantially the entire width except for both ends slightly by the coating device 8. Drying the support 4
0, the applied magnetic paint is dried, and the dried support 12 with a magnetic layer is taken up by a take-up roll 14 via various rollers such as a guide roller to obtain a desired magnetic recording medium. It has gained.

The manner in which the coating material is applied to the support 4 by the coating device 8 will be described in detail with reference to FIG. The coating device 8 includes a gravure roll 16 and a back roll 18. A guide roll 20 is provided upstream of the coating device 8, and a guide roll 22 is also provided downstream. A groove 24 is provided on the entire outer peripheral surface of the gravure roll 16.
Are formed at a predetermined pitch, and the magnetic paint is filled in these grooves 24. The amount of the magnetic paint applied to the support 4 is determined by the pressing force of the back roll 18, the amount of the magnetic paint supplied from the upstream side of the contact portion between the gravure roll 16 and the support 4 (bead condition), or It is adjusted by the traveling speed of the support 4.

When the magnetic coating material is applied to one surface of the support 4 by the coating device 8, the support 4 is guided and supported by the guide rolls 20 and 22 in the vicinity of the coating device 8, and the pressing force is reduced. The vehicle is run at the above-mentioned predetermined speed while being sandwiched between the adjusted gravure roll 16 and the back roll 18. As a result, the gravure roll 16
Thereby, a magnetic paint is applied, and a layer of the magnetic paint having a predetermined thickness can be formed.

[0006]

When the adjustment of the bead condition or the like is not properly performed, the magnetic paint once adhered to the surface of the support 4 is
A part thereof becomes the scattered paint 26 shown in FIG. 4 and scatters on the downstream side of the coating device 8, so that the magnetic paint may drop out on the support 4. Such paint dropout greatly changes depending on the bead condition, the pressing force of the back roll, or the running speed of the support 4, that is, the coating speed. FIG. 5 is a graph showing the distribution of dropouts at different application speeds. The horizontal axis of this graph shows the coating speed (m / min), and the vertical axis shows the production of a pancake from a magnetic recording medium manufactured by applying a magnetic paint to the surface of the support 4 by a coating device 8. 1
Shown is the number of dropouts generated over a two minute period per pancake. However, the dropout detection level was -17 dB / 11 μsec.

[0007] From this measurement result, the coating speed is low
In the case of 80 m, as shown by the distribution curve A, the number of dropouts remains at about 3.5 at the center, and the distribution range in which the dropout occurs is narrow.
As the coating speed increases to 5 m, 320 m / min, and 366 m / min, the number of occurrences of dropouts increases to about 8.0 as shown by the distribution curves B, C, and D, and dropouts occur. It can be seen that the distribution also spreads.
As described above, the frequency of occurrence of dropout varies depending on the application speed, and also varies depending on the pressing force of the back roll 18 and the supply amount of the magnetic paint to the gravure roll 16, so that the quality of the magnetic recording medium is kept stable. In order to always ensure high quality, it is necessary to adjust these conditions appropriately. However, this adjustment is subtle and requires a great deal of skill to make an accurate adjustment. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a magnetic recording medium that enables easy and appropriate adjustment of bead conditions and the like without depending on the skill of an operator.

[0008]

In order to achieve the above object, the present invention achieves the above object by using a first roll having a magnetic coating applied thereon and a second roll opposing the first roll. In a method for manufacturing a magnetic recording medium in which the magnetic paint is applied to the support, the paper is disposed downstream for a predetermined time near the contact portion between the first roll and the support, It is determined whether the magnetic paint has adhered to the paper by visually observing the paper, or the amount of the magnetic paint adhered to the paper is determined.Based on the result of the determination, the second value of the magnetic paint is determined. At least one of a supply amount to one roll, a pressing force of one of the first and second rolls to a counter roll, and a traveling speed of the support is adjusted.

In the method of manufacturing a magnetic recording medium according to the present invention, paper is arranged in the vicinity of the contact portion between the first roll and the support for a certain period of time, and based on the presence or absence of the magnetic paint adhered to the paper, At least one of the supply amount of the magnetic paint to the first roll, the pressing force of one of the first and second rolls to the other roll, and the traveling speed of the support is adjusted. Therefore, the presence or absence of the magnetic paint that causes dropout can be easily determined by visually observing the paper, and based on the result of the determination, the bead condition and the pressure of the roll are adjusted so that the magnetic paint does not scatter. The force or the running speed of the support can be adjusted. Therefore, even an operator with relatively low skill can easily and appropriately perform these adjustments, and can maintain a high quality magnetic recording medium by reducing dropout without depending on the skill of the operator. Becomes

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. The method of manufacturing a magnetic recording medium according to the present invention described here is performed in the step of applying a magnetic paint in the manufacture of a magnetic recording medium as shown in FIG. It is carried out in places. FIG. 1 is an explanatory diagram showing one step in carrying out the present invention. In the figure, a coating device 8 is the coating device shown in FIG. 4, and the same components are denoted by the same reference numerals. Description of each component is omitted here. This coating device 8
When the magnetic paint is applied to one surface of the support 4 by the method, the support 4 is guided and supported by the guide rolls 20 and 22 in the vicinity of the coating device 8 and the support 4 is supported by the gravure roll 16 (the present invention). Is run between the back roll 18 (the second roll according to the present invention) and the back roll 18 (the second roll according to the present invention).

The grooves 24 are formed at a predetermined pitch on the entire outer peripheral surface of the gravure roll 16 as described above, and the magnetic paint is filled in these grooves 24. Then, by pressing the back roll 18 against the gravure roll 16 with an appropriate pressing force, the magnetic paint filled in the groove 24 of the gravure roll 16 is applied to the support 4, and the magnetic paint is coated on one surface of the support 4. Is formed.

In this embodiment, in the state where the support 4 is running, as shown in FIG. 1, a strip-shaped white paper P is applied to the contact portion between the gravure roll 16 and the support 4. On the downstream side in the vicinity, the surface is arranged substantially parallel to the gravure roll 16 with the surface facing the contact portion, and the state is changed from 30 seconds to 60
Hold for seconds.

Accordingly, when the scattered paint 26 is generated, the scattered paint 26 adheres to the surface of the paper P. After the elapse of the predetermined time, the surface of the paper P is visually observed. FIG. 2 is an explanatory diagram showing the surface of the paper P at this time. As shown in FIG. 2, when the paint is scattered, it adheres to the surface of the paper P, and the surface of the paper P becomes dirty. State.

When the scattered paint 26 adheres to the surface of the paper P, the operator determines that the bead condition is inappropriate, and adjusts the supply amount of the magnetic paint to the gravure roll 16. Thereafter, the paper P is placed again under the above-described conditions, and if the scattered paint 26 adheres to the paper P even after the adjustment, the adjustment is performed again, and on the other hand, the scattered paint 26 no longer adheres. In this case, the adjustment is completed.

As described above, in the present embodiment, the presence or absence of the magnetic paint causing dropout can be easily determined by visually observing the paper, and based on the determination result, the magnetic paint is prevented from scattering. The bead condition, the pressing force of the roll, or the running speed of the support can be adjusted so as not to cause this. Therefore, even an operator with relatively low skill can easily and appropriately perform these adjustments, and can maintain a high quality magnetic recording medium by reducing dropout without depending on the skill of the operator. Becomes

The support 4 is made of, for example, a polyester film, and the magnetic recording medium manufactured as described above can be used for an audio tape or a video tape. In the above embodiment, the supply amount of the magnetic paint to the gravure roll 16 is adjusted in order to eliminate the scattering of the paint. However, in addition to adjusting the supply amount of the magnetic paint, the back roll 18 is pressed against the gravure roll 16. The scattering of the paint can also be eliminated by adjusting the force and the traveling speed of the support 4. Further, instead of adjusting the pressing force of the back roll 18 to the gravure roll 16, the same result can be obtained by adjusting the pressing force of the gravure roll 16 to the back roll 18.

It is not impossible to use a synthetic resin film or the like in place of the paper P. However, such a material is easily charged, and there is a possibility that unnecessary scattered paint from the surroundings may be absorbed by static electricity. is there. Therefore, paper is superior in that paint scattering can be accurately evaluated. The color of the paper P is most desirably white in that the attached scattered paint 26 can be easily identified. However, it is not impossible to identify the scattered paint 26 even with other colors, and therefore, it is not always limited to white.

[0018]

As described above, in the method of manufacturing a magnetic recording medium according to the present invention, paper is disposed near the contact portion between the first roll and the support for a certain period of time, and the magnetic paint adhered to the paper is removed. At least one of the supply amount of the magnetic paint to the first roll, the pressure contact force of one of the first and second rolls to the counter roll, and the traveling speed of the support is adjusted based on the presence or absence and the amount of the paint. I do. Therefore, the presence or absence of the magnetic paint that causes dropout can be easily determined by visually observing the paper, and based on the result of the determination, the bead condition and the pressure of the roll are adjusted so that the magnetic paint does not scatter. The force or the running speed of the support can be adjusted. Therefore, even an operator with relatively low skill can easily and appropriately perform these adjustments, and can maintain a high quality magnetic recording medium by reducing dropout without depending on the skill of the operator. Becomes

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one step in carrying out the present invention.

FIG. 2 is an explanatory diagram illustrating a front surface of a paper P.

FIG. 3 is a schematic view showing a step of applying a magnetic paint in the manufacture of a magnetic recording medium.

FIG. 4 is a configuration diagram of a coating apparatus used in the coating step of FIG. 3;

FIG. 5 is a graph showing the distribution of dropouts at different application speeds.

[Explanation of symbols]

2 ... supply roll, 4 ... support, 6 ... pinch roll, 8 ... coating device, 10 ... drying device, 12 ... support with magnetic layer, 14 ... take-up roll, 16 ... gravure Rolls, 18 Back rolls, 20 Guide rolls, 22 Guide rolls, 24 Grooves, 26 Spatter paint.

Claims (6)

[Claims] 1. A first roll to which a magnetic paint is adhered,
In the method for manufacturing a magnetic recording medium, wherein the magnetic paint is applied to the support with a running support sandwiched by a second roll opposed to the first roll, the first roll is fixed for a predetermined time. And disposing paper on the downstream side in the vicinity of the contact portion with the support, and then visually checking the paper to determine whether the magnetic paint has adhered to the paper, or whether the magnetic paint has adhered to the paper. And the supply amount of the magnetic paint to the first roll, the pressing force of one of the first and second rolls to a counterpart roll, and A method for manufacturing a magnetic recording medium, wherein at least one of the traveling speeds is adjusted. 2. The method according to claim 1, wherein the predetermined time is 30 seconds to 60 seconds. 3. The method according to claim 1, wherein the paper is white. 4. The magnetic recording medium according to claim 1, wherein grooves are formed on the outer peripheral surface of the first roll at a predetermined pitch, and the magnetic paint fills the grooves. Production method. 5. An audio tape or a video tape is manufactured from a magnetic recording medium.
The manufacturing method of the magnetic recording medium according to the above. 6. The method according to claim 1, wherein the support is a polyester film.