JP2605839B2 - Method and apparatus for manufacturing magnetic recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a ferromagnetic metal thin film type magnetic recording medium, and particularly to a lubricant layer as a top coat layer after forming a metal thin film layer for improving practical performance. Provides a means for forming a homogeneous lubricant layer by a vacuum evaporation method.

Conventional technology Co, Ni, Fe or alloys containing them as the main components are polymer films such as polyester films and polyimide films, non-magnetic metal substrates, etc. by vacuum deposition, sputtering, ion plating, etc. The ferromagnetic metal thin film type magnetic recording medium formed on a substrate made of is capable of dramatically improving the recording density as compared with a conventional coating type magnetic recording medium. As conditions for this high recording density, it is important to reduce recording / reproducing defects as much as possible and to reduce spacing loss between a magnetic head and a recording medium as much as possible. It is necessary to be. In order to solve these problems, there is a method of forming a lubricant layer as a top coat after forming a metal thin film layer by forming a lubricant such as a fatty acid, a fatty acid ester, or a fatty acid amide by a vacuum evaporation method.

Hereinafter, an example of a method for manufacturing the above-described magnetic recording medium will be described with reference to the drawings.

FIG. 4 shows the structure of a magnetic recording medium, and FIG. 5 shows a conventional method and apparatus for manufacturing a magnetic recording medium.

In FIG. 4, 1 is a substrate, 2 is a ferromagnetic metal thin film layer formed by a film forming method in a vacuum, 3 is a back coating layer, and 4 is a lubricant layer as a top coat layer.

In FIG. 5, reference numeral 11 denotes a magnetic recording medium before forming a top coat, which is wound in a roll. 12 and 14 are pass rolls and 13 is a main roll, which closely transports the magnetic recording medium. Reference numeral 15 denotes a magnetic recording medium on which a top coat has been formed, and is continuously wound. Reference numeral 16 denotes an evaporation source filled with a lubricant, and 17 denotes a heat medium tank that indirectly heats and melts and evaporates the lubricant of the evaporation source 16. Reference numeral 18 denotes a heat medium circulating device, which controls the temperature of the heat medium, supplies the heat medium to the heat medium tank 17, and is provided outside the vacuum tank. Reference numeral 19 denotes an anti-adhesion plate, which is provided to prevent the evaporated particles of the lubricant from contaminating the magnetic recording medium in the vacuum chamber or the component parts that convey it. Reference numeral 20 denotes an evaporation rate monitor for detecting the amount of evaporation and adjusting the temperature of the heat medium of the heat medium circulation device 18.

The operation of the conventional method for manufacturing a magnetic recording medium configured as described above will be described below.

When the lubricant layer 4 is formed on the non-magnetic substrate 1 on which the ferromagnetic metal thin film layer 2 is formed by a vacuum deposition method, the lubricant is first melted by the thermal evaporation source 16 and when the evaporation amount reaches a specified amount. The substrate 1 is transported to form a lubricant layer 4 as a top coat.

Problems to be Solved by the Invention However, when a lubricant layer is formed as a top coat by a conventional vacuum deposition method, when the evaporation rate of the lubricant is increased to increase the film formation rate, the lubricant is aggregated, and the A lubricant layer cannot be formed. In addition, a part of the aggregated lubricant adheres to rollers and the like in the apparatus, which not only promotes contamination of the apparatus, but also causes a magnetic head, a rotating cylinder, a tape running post, and the like to be used in recording and reproduction with a video tape recorder. As shown in FIG. 3, contamination is increased and dropout as a recording / reproducing defect is increased as the film formation speed is increased. Therefore, there is a problem that it is difficult to increase the film formation speed.

The present invention has been made in view of the above problems, and provides a method of manufacturing a magnetic recording medium by a vacuum evaporation method and an apparatus for manufacturing the magnetic recording medium, in which the agglomeration of a lubricant is reduced while improving the film forming rate.

Means for Solving the Problems In order to solve the above problems, a method for manufacturing a magnetic recording medium of the present invention is to run a magnetic recording medium having a ferromagnetic metal thin film formed on a non-magnetic substrate in a certain direction, In a method of continuously forming a lubricant layer as a top coat by a vacuum evaporation method, at least both ends of a top coat formation area on the magnetic recording medium are supported by pass rollers, and the ferromagnetic metal thin film layer is passed through the pass rollers. Power density of 0.05
It is characterized by energizing at ~ 0.2 W / cm ² .

Further, the apparatus for manufacturing a magnetic recording medium of the present invention includes a transfer device for transferring a magnetic recording medium having a ferromagnetic metal thin film layer formed on a non-magnetic substrate in a fixed direction, and a transfer device for transferring the magnetic recording medium on a transfer path of the magnetic recording medium. And a vapor deposition device for forming a lubricant layer as a top coat layer on the ferromagnetic metal thin film layer by a vacuum vapor deposition method, the top coat on the magnetic recording medium at least on the transfer path. A pass roller supporting both ends of a formation area; and a power supply for supplying power to the contact portion of the transfer device with the magnetic recording medium from before and after the vapor deposition device through the pass roller to supply current to the ferromagnetic metal thin film layer. A device is provided.

According to the present invention, the temperature rises when electricity is supplied to the metal thin film layer, and the radiant heat prevents aggregation of the lubricant particles. Further, when the metal thin film layer arrives at the substrate, the lubricant is easily diffused due to the temperature rise of the metal thin film layer itself, and a uniform lubricant layer can be formed. As a result, the agglomerated lubricant does not adhere to the rollers or the like to promote contamination of the apparatus, and dropout as a recording / reproducing defect can be greatly reduced.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of a device configuration in one embodiment of the present invention. The basic structure of the magnetic recording medium manufactured in this embodiment is the same as that shown in FIG.
A non-magnetic substrate 1 is made of a PET film having a thickness of 0.1 to 0.2 μm.
A ferromagnetic metal thin film layer 2 is formed by oblique vapor deposition of Co-Ni having a thickness of μm, and a mixture of a resin and carbon is applied as a back coating layer 3 on the back surface to a thickness of about 0.3 to 1 μm to improve running properties.

In FIG. 1, reference numeral 21 denotes a magnetic recording medium before the lubricant layer 4 is formed, which is sent to the lubricant layer 4 formation area and its tension is controlled to 0.5 to 20 kgf corresponding to a width of 500 mm. Reference numerals 22 and 24 denote pass rollers which rotate in close contact with the magnetic recording medium. Reference numeral 23 denotes a main roller which controls and conveys the magnetic recording medium at a constant speed (0.1 to 200 m / min). Reference numeral 25 denotes a magnetic recording medium on which the lubricant layer 4 has been formed.
It is continuously wound with a tension of 0.5 to 20 kgf corresponding to a width of 0 mm, and the taper tension can be controlled. 26 is an evaporation source, in which fatty acids, fatty acid esters,
It is filled with fatty acid amide or the like, and is melted and deposited.
Reference numeral 27 denotes a heat medium tank, which heats and melts the lubricant. 28 is a heat medium circulation device provided outside the vacuum chamber,
Thus, the temperature of the heat medium is controlled and the heat medium is supplied to the heat medium tank 27. Numeral 29 denotes an anti-adhesion plate, which prevents the evaporated particles of the lubricant from contaminating the magnetic recording medium in the vacuum chamber or the component parts for transporting the same. Produced by things. The amount of evaporation of the lubricant particles is detected by the evaporation rate monitor 30 to control the temperature of the heat medium of the heat medium circulation device 28. Reference numeral 31 denotes a shutter, which is opened after reaching a predetermined evaporation rate, and starts vapor deposition on the substrate. Reference numeral 32 denotes an energizing power supply provided outside the vacuum chamber, which energizes the metal thin film layer via a pass roller and has a capacity of 5 KW.

The operation of the method and apparatus for manufacturing a magnetic recording medium of the present invention configured as described above will be described with reference to FIG.

Before the lubricant layer 4 is formed, the magnetic recording medium is a ferromagnetic metal thin film layer 2.
In order to form the lubricant layer 4 as a top coat, the sheet is continuously and closely fed to the main roller 23 while being energized by pass rollers or unwinding. Further, the lubricant is heated and melted by the heat medium from the heat medium circulating device 28 and starts to evaporate. When the evaporation rate reaches a specified rate, the shutter 31 is opened, the lubricant particles reach the substrate, and a lubricant layer is formed. At this time, since the ferromagnetic metal thin film layer 2 of the non-magnetic substrate 1 is energized, the radiant heat heats the lubricant layer, thereby preventing the aggregation of the lubricant particles and simultaneously dispersing the lubricant particles into the metal thin film layer. A uniform lubricant layer can be formed.

FIG. 2 shows that the nonmagnetic substrate 1
Dropout when changing the current flowing through the metal thin film layer when the width of the ferromagnetic metal thin film layer is 500 mm, the thickness of the ferromagnetic metal thin film layer is 0.15 μm, the main roller diameter is 1 m, the energizing interval is about 2 m, and the forming speed is 30 m / min Shows the change in number.

It should be noted that W / cm ² is used as a unit of the conducting current on the horizontal axis of the graph of FIG.

The number of dropouts is 15 μs or more when a video signal is recorded and reproduced for 10 minutes using a rotating cylinder type video tape recorder at a tape width of 8 mm, a relative speed of 3.8 m / s, a tape speed of 1.4 cm / s, and a track pitch of about 20 μm. It is the average value per minute of the signal loss of 16 dB or more during the period.

From the graph of FIG. 2, it can be seen that the conduction current is 0.05 W / cm ^{2 to} 0.2 W / cm.
A remarkable reduction in the number of dropouts was observed in the range of ² ,
It is understood that practical use is sufficiently possible in this range.

Effects of the Invention As described above, according to the present invention, a magnetic recording medium in which a ferromagnetic metal thin film layer is formed on a non-magnetic substrate, a lubricant layer is applied as a top coat layer to the ferromagnetic metal thin film layer by applying a vacuum deposition method to the ferromagnetic metal thin film layer. By forming the film, it is possible to reduce the aggregation of the lubricant while improving the film forming speed, and as a result, there is a specific effect that the dropout as a recording / reproducing defect is greatly reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a method of forming a lubricant layer by vacuum evaporation while energizing a metal thin film layer in one embodiment of the present invention;
FIG. 2 is a diagram showing the relationship between the number of dropouts and the current density when the film forming speed is constant, FIG. 3 is a diagram showing the relationship between the number of dropouts and the film forming speed in the conventional method, and FIG. FIG. 5 is a cross-sectional view showing the structure of a magnetic recording medium, and FIG. 5 is a view showing a method of manufacturing a conventional magnetic recording medium. DESCRIPTION OF SYMBOLS 1 ... Non-magnetic substrate, 2 ... Ferromagnetic metal thin film layer, 4 ... Lubricant layer, 21, 25 ... Magnetic recording medium, 22, 24 ... Pass roller,
23: a main roller; 25: a magnetic recording medium having a lubricant layer formed thereon; 26, an evaporation source; 27, a heating medium tank; 28, a heating medium circulating device;

Claims (2)

(57) [Claims] A method in which a magnetic recording medium having a ferromagnetic metal thin film layer formed on a non-magnetic substrate is run in a fixed direction, and a lubricant layer is continuously formed thereon as a top coat by a vacuum deposition method. Both ends of the top coat formation area on the magnetic recording medium are supported by pass rollers, and the power density is applied to the ferromagnetic metal thin film layer via the pass rollers.
A method for producing a magnetic recording medium, comprising applying a current at 0.05 to 0.2 W / cm ² . 2. A transfer device for transferring a magnetic recording medium having a ferromagnetic metal thin film layer formed on a nonmagnetic substrate in a fixed direction, and a transfer device for transferring the magnetic recording medium on the ferromagnetic metal thin film layer on a transfer path of the magnetic recording medium. In a magnetic recording medium manufacturing apparatus having a vapor deposition device for forming a lubricant layer as a top coat layer by a vacuum vapor deposition method, at least both ends of a top coat formation area on the magnetic recording medium are supported on the transfer path. A pass roller, and a power supply device for supplying power to the contact portion of the transfer device with the magnetic recording medium from before and after the vapor deposition device to supply electricity to the ferromagnetic metal thin film layer via the pass roller. For manufacturing a magnetic recording medium.