JPS59201230A - Manufacture of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a wrinkleless vertical magnetic recording medium by providing a potential difference between a cylindrical can and a conductor film, and running around an auxiliary heat roller of prescribed temperature before the substrate contacts the cylindrical can and pressing it with a nip roller. CONSTITUTION:The auxiliary heat roller 11 has its peripheral surface held at temperature >=1/2 and <=1/1 as high as the temperature of the peripheral surface of the cylindrical can 2. The substrate 8 made of high polymer material having the conductor film on the surface is sent from the auxiliary heat roller 11 and runs along the nip roller 3' immediately to be processed by the cylindrical can 2. Thus, the deformation of the substrate due to abrupt temperature variation which occurs when the substrate 8 contacts the cylindrical can 2 is reduced to obtain excellent wrinkleless vertical magnetic recording media.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a perpendicular magnetic recording medium with excellent high-altitude recording characteristics.
Regarding the i-blue method.

A perpendicular magnetic recording system has been known as a conventional magnetic recording system with a single-tari structure and excellent short wavelength recording capability. This makes full use of the residual reduction in the perpendicular direction on the magnetic surface of the magnetic recording medium. Therefore, in this method, it is safe to use a perpendicularly magnetized film in which residual magnetization remains in a direction substantially perpendicular to the film surface. As a perpendicular magnetization film,
So-called co-O whose main components are Co and L-Or
The r-perpendicular magnetization film has excellent characteristics. Go-Or perpendicularly magnetized films can be fabricated by sputtering or vacuum evaporation (including methods such as ion blating, which ionizes some of the evaporated atoms to deposit the film), but the latter method is particularly difficult to fabricate. Accordingly, very low film deposition rates can be achieved and the method is widely used. However, as will be explained below, when a Go-Or perpendicular magnetization film was actually fabricated by a vacuum evaporation method, various wrinkles occurred. If wrinkles occur, it is impossible to use the material as a magnetic recording medium, and some kind of solution is required.

As a method for producing a Go--Cr perpendicularly magnetized film by a vacuum evaporation method, a method in which the evaporation is performed while the substrate is moved along the circumferential surface of a cylindrical can is excellent. 1st
This method will be explained using (2). A tape-shaped substrate 1 made of a polymeric material runs along the circumferential surface of a cylindrical can 2. 3 is a substrate roller 11111, 4 is a substrate exit roller, c6 is an evaporation source that guides and runs the tape-shaped substrate 1, and 6 is a stiffening plate. The operation of the conventional vacuum evaporation mold constructed as described above will be described below. The substrate 1 made of a polymeric material guided by the substrate insertion roller 3 travels along the circumferential surface of the cylindrical can 2 as the cylindrical can 2 rotates, and is guided to the winding side by the substrate exit roller 4. Note that the cylindrical can can have a circumferential surface temperature set to any temperature up to around 350°C. Evaporation #j5 heats and evaporates the Go-Cr alloy innit. Only the evaporated atoms having a component close to normal incidence stick to the substrate 1 made of a polymer material by the shielding plate 6, thereby forming a Go--Cr perpendicularly magnetized film.

However, when a Go--Cr perpendicular magnetization film is manufactured with the above structure, the following problems occur. When one word is recorded and reproduced in a Go--Cr perpendicularly magnetized film, the larger the film has a coercive force Hc in the direction perpendicular to the film surface, the higher the reproduction output can be obtained. H.O.
The temperature increases as the substrate temperature Tsub during vapor deposition increases. In order to put the Cjo-Cr perpendicular magnetization film into practical use,
A Ha↓ of at least 4000e is required, but the experimental results show that Tsub must be set to 12σC or more for this purpose.More preferably, a film with a Ha value of 80000 or more is required. However, in this case, Tsub must be set to 200°C or higher. Note that the substrate temperature Tsub during vapor deposition refers to the temperature of the circumferential surface of the cylindrical can. Further, as the substrate made of a polymeric material, a polyethylene terephthalate film or a haphoryamide film is suitable from the viewpoint of surface properties, stability, mass productivity, etc. However, when these films are evaporated by the method shown in FIG. 1 at a temperature of 120° C. or more on the circumferential surface of a cylindrical can, step-like wrinkles occur in the evaporated portion. FIG. 2 shows this state. 7 is a wavy wrinkle. It has been found that such wavy wrinkles occur in the deposition area when the cylindrical can 2 and the substrate 1 are not sufficiently contacted.

Therefore, one idea to prevent this is to form a conductive film on the substrate 1 made of a polymeric material, create a potential difference between the conductive film and the cylindrical can 2, and bring them into close contact using electrostatic attraction. It will be done.

Note that when permalloy or T1 is used as this conductive film, the recording/reproducing characteristics and orientation of the perpendicular magnetic recording medium are improved. FIG. 3 is a three-dimensional diagram showing a state in which a Go-Or film is deposited by providing a potential difference between the conductor film and the cylindrical can 2, as described above. 8 is a substrate made of polymer material,
A conductor film is formed on the surface (the surface not in contact with the cylindrical can 2).

The voltage applied between the conductor film and the cylindrical can 2 may be a DC voltage or an AC voltage.

According to the above method, the wavy wrinkles disappear as shown in FIG. 3, but when the substrate 8 comes into contact with the cylindrical can 2,
Random wrinkles 9 occur. This random wrinkle 9
The reason for the occurrence of G' can be considered as follows. When the substrate 8 comes into contact with the cylindrical can 2, since the cylindrical can 2 is at a high temperature, the substrate 8 is rapidly heated and deformed. Since the substrate 8 is brought into close contact with the cylindrical can 2 due to the potential difference in a state where the deformation is not corrected, random wrinkles occur in the substrate 8.

FIG. 4 is a three-dimensional view of a device that attempts to improve the random wrinkles in FIG. 3. Although it is almost the same as FIG. 3, in FIG. 4, the substrate entrance roller 3 is replaced with a nip roller 3'. The surface of the nip roller is generally made of rubber. A substrate 8 made of a polymer material and having a conductive film formed on its surface is pressed against the cylindrical can 2 by a nip roller 3' when it starts to come into contact with the cylindrical can 2. However, even with this configuration, by increasing the temperature of the cylindrical can 2 and applying a voltage between the substrate 8 and the cylindrical can 2,
When a Go-Cr perpendicularly magnetized film is fabricated, when the substrate 8 comes into contact with the cylindrical can 2, deformation occurs due to rapid heating, and before this deformation can be corrected, it is pressed down by the nip roller 3', resulting in folding. Wrinkles 10 occur.

As described above, the conventional configuration has the problem that wrinkles occur in the substrate made of a polymer material when the Go-1r perpendicular magnetization film is deposited, making it unusable as a magnetic recording medium.

Purpose of the Invention 'Rise above C? A perpendicularly magnetized film containing Cjo and Or as main components is vacuum-deposited on a substrate made of a polymeric material with a conductive film formed on its surface, which is running smoothly around the circumferential surface of the cylindrical can. When forming the cylindrical can by the method, a potential difference is provided between the cylindrical can and the conductive film, and the temperature of the circumferential surface of the cylindrical can is set to T (°C) before the substrate is brought into contact with the cylindrical can. When /2
The substrate is heated by passing it along a preheating roller whose peripheral surface temperature is set within the range of −T (°C), and when the substrate starts to come into contact with the cylindrical can, it is pressed down with a nip roller. 1. By using the method of the present invention, a wrinkle-free perpendicular magnetic recording medium can be obtained. DESCRIPTION OF EMBODIMENTS The invention will be explained with reference to FIG. FIG. 5 is a front view of the inside of the vacuum evaporation apparatus, showing an example of the central spasm of the invention. 1
1 is a preheating roller whose circumferential surface is a cylindrical can 2
The temperature is set to be above A and below A of the temperature of the peripheral surface of. A conductive film is formed on the surface after leaving the preheating roller.
c The substrate 8 made of a polymeric material is immediately moved to the nip roller 3.
', and is pressed down by the cylindrical can 2.

Note that it is better to keep the length of the path where the substrate 8 leaves the preheating roller and enters the nip roller as short as possible (-but in a vacuum, less heat escapes from the heated substrate 8, There is no problem even if this length is a little long. - Since the nip roller 37 is still in contact with the cylindrical can 2, the temperature is close to the temperature of the surface of the cylindrical can. This is a metal roller connected to a power source 13 in order to create a potential difference with the shaped can 2. 14 is a free roller.

In FIG. 5, the substrate 8 is heated by a preheating roller 11 to raise its temperature. As a result, deformation of the board due to rapid temperature changes that conventionally occurred when the board 8 came into contact with the cylindrical can 2 is reduced, and when the board 8 is pressed against the cylindrical can 2 by the nip roller 3' in a heated state, Experiments have shown that it is possible to prevent the appearance of wrinkles.

Note that wrinkles occurred when the temperature of the circumferential surface of the preheating roller was less than the temperature of the circumferential surface of the cylindrical can.

Furthermore, if the temperature of the circumferential surface of the preheating roller is lower than the temperature of the horse surface of the cylindrical can, even if wrinkles appear when it comes into contact with the former, those wrinkles disappear when it comes into contact with the latter. When the temperature exceeded the temperature of the circumferential surface of the cylindrical can, the wrinkles that appeared when contacting the former remained even after vapor deposition.

Next, a first specific embodiment of the invention will be described.

Thickness: 18 μm using vacuum evaporation equipment as shown in Figure 6.
Film thickness: 500 mm on polyethylene terephthalate film
A titanium film was deposited, and a perpendicularly magnetized co-cr film having a thickness of 2,000 yen was deposited thereon. During the T1 film deposition, the temperature of the circumferential surface of the cylindrical can 2 was set to room temperature, so
There were no wrinkles. Further, a Go-Cr perpendicular magnetization film is vaporized on top of the T1 film. The temperature was set at 80° C., and a voltage of -200 V was applied to the metal roller 12 using @, #13.When vapor deposition was performed in this manner, no wrinkles were generated.

In addition, the HCL of the Go-Cr perpendicular magnetization film (7) is 5100e, and compared to 8 or more which showed excellent short wavelength recording and reproducing characteristics, the temperature of the circumferential surface of the heat roller 11 was adjusted by When the Go-Cax film was deposited at 26° C. vi, creases as shown in FIG. 4 were generated.

Next, a second specific embodiment of the invention will be described.

A 1-permalloy film with a thickness of 2000 μm was deposited on a polyamide film with a thickness of 9 μm using a vacuum deposition apparatus as shown in FIG.
A perpendicularly magnetized film was deposited. During permalloy film deposition,
Since the temperature of the circumferential surface of the cylindrical can 2 was set to room temperature, no wrinkles were formed. Further Go − on top of the permalloy film
When depositing the Cr vertically magnetized film, the temperature of the circumferential surface of the cylindrical can 2 is set to 230°C, the temperature of the circumferential surface of the preheating roller 11 is set to 150°C, and the power source 13
A voltage of 00V was applied. There were no wrinkles in the obtained perpendicular magnetic recording medium. In addition, the Co--Cr vertically magnetized film 17) HCL was 84008, and exhibited excellent short-length recording and reproducing characteristics.

Effects of the Invention According to the method of the present invention, the problems that conventionally occurred when depositing a Go-Cr perpendicular magnetization film on a substrate made of a polymer material, can be avoided.
It is possible to completely remove wrinkles, and a wrinkle-free perpendicular magnetic recording medium can be provided.

[Brief explanation of drawings]

FIG. 1 is a front view of the interior of a conventional vacuum evaporation apparatus for producing a Co--Cr perpendicular magnetization film, and FIGS. 2, 3, and 41 are three-dimensional views. FIG. 5 is a front view of the inside of a vacuum evaporation apparatus for explaining the present invention in detail. 1...Substrate made of polymeric material, 2...
Cylindrical can, 3'...Nig roller, 5...
. . . Evaporation source, 8 . . . A substrate made of a polymeric material on which a conductive film is formed, 11 . . . Preheating roller. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] On a substrate made of a polymeric material with a conductive film formed on the surface, which is running along the circumferential surface of a cylindrical can heated to 120° C. or higher, GO and Or are mainly deposited. When forming the perpendicularly magnetized film as a component by vacuum evaporation, a potential difference is provided between the cylindrical can and the conductive film, and the substrate is
Before contacting the inner oily can, there is a vortex on the circumferential surface of the cylindrical can, where T degree is T (°C), the crystallinity of the surface C is /2~T('0
A method for manufacturing a perpendicular magnetic recording medium, characterized in that the substrate is heated by heating it with a preheating roller set within a range of 1, and is pressed down with a nip roller when the substrate starts to come into contact with the cylindrical can.