JPH0479024A - Method and device for manufacturing magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium with the satisfactory surface smoothness of a magnetic coating film and the high electromagnetic converting characteristic by bringing a smoothing device to obliquely contact the surface of the magnetic coating film having fluidity obliquely to the travelling direction of a base body film. CONSTITUTION:A magnetic coating film 7 is formed by applying the prescribed quantity of magnetic coating 3 onto a polyester film 5 travelling while being crimped to a gravure roll 1 by the pressure of an impression cylinder roll 6. After the magnetic coating film 7 is formed, a plate-shaped smoothing device 8 executes a smooth processing by being crossed and brought into contact with the surface of the magnetic coating film 7 obliquely to the travelling direction while the magnetic coating film 7 has fluidity. Therefore, when there is flaw or stripes, etc., caused by the engagement of a foreign material on the gravure roll 1 or a doctor blade 4, even in the case of generating the flaw or stripes, etc., similarly on the magnetic coating film 7 coated by the gravure roll 1, it can be recovered by moving the magnetic coating film 7 with fluidity in the oblique direction. Thus, the magnetic recording medium can be obtained with the satisfactory surface smoothness and the high electromagnetic converting characteristic.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium and an apparatus thereof, and more particularly, to a magnetic recording medium having a magnetic coating film with good surface smoothness and excellent electromagnetic conversion characteristics. The present invention relates to a method for manufacturing a medium and an apparatus for manufacturing the same.

[Conventional technology]

In general, magnetic recording media such as magnetic tape are produced by dipping the lower part of the gravure roll 1 into a magnetic paint 3 placed in a magnetic paint tank 2 in the direction shown by arrow A, as shown in FIGS. 3 and 4. After scraping off the excess magnetic paint with a doctor blade 4, it is placed on a base film 5, such as a polyester film, which is sandwiched between the gravure roll 1 and an impression roll 6 rotating in the direction of arrow B. While the magnetic coating film 7 formed by this coating is in an undried state, a plate-shaped smoothing device 81 installed perpendicularly to the running direction of the base film 5 is used to smooth the magnetic coating film 7. It is brought into contact with the surface and smoothed.

[Problem to be solved by the invention]

However, in the conventional method of smoothing the magnetic coating film 7 using the plate-shaped smoothing device 81 installed perpendicularly to the running direction of the base film 5, the gravure roll 1 or the doctor blade 4. If scratches or streaks occur due to foreign objects being bitten, the same scratches or streaks will occur on the magnetic coating 7, making it impossible to perform a complete smoothing process, and the surface smoothness of the magnetic coating will deteriorate. However, it is not possible to obtain a magnetic recording medium with good electromagnetic conversion characteristics.

[Means to solve the problem]

This invention was made as a result of various studies in view of the current situation, and by bringing a smoothing device into cross-contact with the surface of a fluid magnetic coating film obliquely to the running direction of the base film, magnetic The coating film is completely smoothed, and a magnetic recording medium with good surface smoothness of the magnetic coating film and excellent electromagnetic conversion characteristics can be obtained.

An embodiment of the magnetic recording medium manufacturing apparatus of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 schematically shows a magnetic recording medium manufacturing apparatus according to the present invention. Reference numeral 1 denotes a gravure roll, the lower part of which is immersed in a magnetic paint 3 in a magnetic paint tank 2, and rotated in the direction of arrow A.

Reference numeral 4 denotes a doctor blade, the tip of which touches the circumferential surface of the gravure roll 1, and rotates the gravure roll 1.
This is to scrape off the excess magnetic paint 3 that has adhered to the surface and been pulled up.

5 is a continuously running polyester film; 6 is an impression roll that presses the running polyester film 5 against the gravure roll 1 and rotates in the direction of arrow B; A predetermined amount of magnetic paint 3 is applied onto the polyester film 5 which is sandwiched between the two and runs, thereby forming a magnetic paint film 7.

8 is a plate-shaped smoothing device for smoothing the magnetic coating film 7 formed on the polyester film 5 in this way, and after the magnetic coating film 7 is formed, it runs between guide rolls 9 and 10. The polyester film 50 is disposed diagonally across the running direction, and the magnetic coating film 7
While the magnetic coating film 70 has fluidity, it is brought into contact with the surface of the magnetic coating film 70 diagonally to the running direction to smoothen the surface.

However, in Gravure Roll 1 and Doctor Blade 4,
If there are scratches or streaks due to biting of foreign matter, etc., the same scratches or streaks will occur on the magnetic coating 7 applied by the gravure roll 1, resulting in uneven thickness, but A plate-shaped smoothing device 8 disposed diagonally across the surface moves the fluid magnetic coating 7 in the diagonal width direction and smooths it, so even if scratches or streaks occur, it is smoothed. , it is repaired by moving the fluid magnetic coating film 7 in the diagonal width direction. Therefore,
Complete smoothing treatment is performed to obtain a magnetic recording medium with good surface smoothness and excellent electromagnetic conversion characteristics.

Here, in order to ensure that the smoothing process of the magnetic coating film 7 is sufficiently performed, the plate-shaped smoothing device 8 is installed on the surface of the magnetic coating film 7 perpendicular to the running direction, as shown in FIG. It is preferable that the angle α at which the contact crosses diagonally from the direction is in the range of more than 0° and less than 60°, and more preferably in the range of more than 0° and less than 30'.

Further, the material of this plate-shaped smoothing device 8 is not particularly limited, and for example, in addition to being made of ceramic, cermet, glass, hard steel, cemented carbide, etc., the main body may be made of metal or plastic material, The surface is preferably plated with hard chrome, or coated with ceramic such as titanium carbide, titanium nitride, or alumina.

〔Example〕 Next, embodiments of the invention will be described.

Examples 1 to 4 Acicular γ-Fe2Q, powder 80 parts by weight (coercive force 650 oersted) Vinyl chloride-vinyl acetate-vinyl 9 Alcohol copolymer polyurethane resin 9 Trifunctional low molecular weight isocyanate 2 Knot compound methyl isobutyl ketone 60〃Toluene
60 This composition was mixed and dispersed in a ball mill for 16 hours to prepare a magnetic paint. This magnetic paint is applied using the magnetic recording medium manufacturing apparatus shown in FIG.
It is coated on a polyester film 5 with a thickness of 12 μm, and the angle α at which the smoothing device 8 crosses diagonally from the direction perpendicular to the running direction of the polyester film and makes contact is set at various angles as shown in Table 1 below. Each was brought into contact with the magnetic coating surface and smoothed to a dry thickness of 6 μm.
A magnetic coating film of m was formed. After that, it was cut to a specified width to make magnetic tape.

Comparative Example 1 In the smoothing treatment of the magnetic coating film in Example 1, the first
The magnetic recording medium manufacturing apparatus shown in FIG. 2 is used instead of the magnetic recording medium manufacturing apparatus shown in the figure, and the smoothing device 81 is brought into contact with the surface of the magnetic coating film in a direction perpendicular to the traveling polyester film 5 to smooth it. A magnetic tape was produced in the same manner as in Example 1 except for the treatment.

Regarding the magnetic tapes obtained in each example and comparative example,
The number of unevenness due to streaks etc. on the magnetic coating film was visually inspected, and the number of unevenness was measured by dividing the size of the unevenness into large, medium and small.

Table 1 below shows the results.

It can be seen that a magnetic recording medium with no Table 1, good surface smoothness, and excellent electromagnetic conversion characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing a magnetic recording medium manufacturing apparatus of the present invention, FIG. 2 is a front view thereof, FIG. 3 is a side view schematically showing a conventional magnetic recording medium manufacturing apparatus, and FIG. 4 is a side view schematically showing the same. It is a front view. 3...Magnetic paint, 5...Polyester film (substrate film), 7...Magnetic coating film, 8...Smoothing device [Effects of the invention] As is clear from Table 1 above, the present invention has the following advantages: The magnetic tapes obtained by the manufacturing method and apparatus (Examples 1 to 4) had the following characteristics compared to the magnetic tape obtained by the conventional method (Comparative Example 1):
In both cases, the number of irregularities due to streaks, etc. is small, and therefore, according to the manufacturing method and apparatus of the present invention, thickness unevenness due to scratches, streaks, etc. Patent Applicant: Hitachi Maxell, Ltd.

Claims (1)

[Claims] 1. Applying a magnetic paint onto a traveling base film, and then, while the magnetic paint film on the base film has fluidity,
A method 2 for manufacturing a magnetic recording medium characterized by smoothing the surface of the magnetic coating film by bringing a smoothing device into contact with the surface diagonally with respect to the running direction of the base film. In the process of applying the paint and smoothing the magnetic coating film while it has fluidity, a smoothing device is placed diagonally across the running direction of the base film and in contact with the surface of the magnetic coating film. A manufacturing apparatus 3 for a magnetic recording medium, characterized in that the smoothing device, which is disposed diagonally across the running direction of the base film, contacts the surface of the magnetic coating film at an angle perpendicular to the running direction of the magnetic coating film. 3. The apparatus for manufacturing a magnetic recording medium according to claim 2, wherein the magnetic recording medium is within a range of more than 0° and 60° or less from the direction in which the magnetic recording medium is produced.