JP2563534B2 - Method and apparatus for manufacturing magnetic recording medium - Google Patents

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 magnetic recording medium, and in particular, a lubricant layer is vacuum-deposited as a top coat layer after forming a metal thin film layer for improving practical performance. The present invention relates to a method and an apparatus for manufacturing a magnetic recording medium for forming a uniform lubricant layer by the method.

Conventional technology Co, Ni, Fe or alloys containing them as the main component are polymer films such as polyester film and polyimide film and non-magnetic metal substrate by vacuum deposition method such as vacuum deposition method, sputtering method and ion plating method. The ferromagnetic metal thin film type magnetic recording medium formed on the substrate made of can significantly improve the recording density as compared with the conventional coating type magnetic recording medium. As a condition, it is important to reduce recording / reproduction defects as much as possible and also reduce spacing loss between the magnetic head and the recording medium as much as possible, and it is also necessary that the recording medium also has durability. To solve them,
As one of methods for forming a lubricant layer as a top coat after forming a metal thin film layer, there is a method for forming a lubricant such as fatty acid, fatty acid ester, and fatty acid amide by a vacuum deposition method.

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

FIG. 4 shows a cross-sectional structure of the magnetic recording medium, and FIG. 5 shows an outline of an apparatus configuration used in a conventional method of manufacturing a magnetic recording medium.

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

In FIG. 5, 11 is a magnetic recording medium before the formation of the top coat, which is wound in a roll. Reference numerals 12 and 14 are pass rollers, and 13 is a main roller, which closely conveys the magnetic recording medium. Reference numeral 15 is a magnetic recording medium on which a top coat has been formed, which 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 in order to prevent the evaporated particles of the lubricant from contaminating the magnetic recording medium in the vacuum chamber or the component parts carrying the same. Reference numeral 20 denotes an evaporation rate monitor for adjusting the temperature of the heat medium of the heat medium circulation device 18 by detecting the amount of evaporation.

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

When the lubricant layer 4 is formed on the non-magnetic substrate on which the ferromagnetic metal thin film layer 2 is formed by the vacuum evaporation method, first the lubricant is evaporated from the evaporation source 16
And the substrate is transported to form the lubricant layer 4 as a top coat when the amount of evaporation reaches a prescribed amount.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, when a lubricant layer is formed as a top coat by the conventional vacuum deposition method described above, when the evaporation rate of the lubricant is increased to improve the film formation rate, the lubricant causes agglomeration and a uniform The lubricant layer cannot be formed. Also, some of the agglomerated lubricant adheres to the rollers inside the device, which not only promotes the contamination of the device, but also contaminates the magnetic head, rotary cylinder, tape running post, etc. during recording and reproduction with a video tape recorder. As a recording / reproducing defect, dropout increases, which makes it difficult to increase the film formation rate.

In view of the above problems, the present invention provides a method for manufacturing a magnetic recording medium by a vacuum vapor deposition method and an apparatus therefor, in which aggregation of a lubricant is reduced while improving a film forming rate.

Means for Solving the Problems In order to solve the above problems, a method of manufacturing a magnetic recording medium according to the present invention is directed to running a magnetic recording medium having a ferromagnetic metal thin film formed on a non-magnetic substrate in a certain direction, and then top In a method of continuously forming a lubricant layer as a coat by a vacuum deposition method, an electrode plate is provided facing the running magnetic recording medium, and an electric potential is applied between the electrode plate and the ferromagnetic thin film layer. Is characterized by.

The magnetic recording medium manufacturing apparatus of the present invention comprises a transfer device for transferring a magnetic recording medium having a ferromagnetic metal thin film layer formed on a non-magnetic substrate in a certain direction, and a transfer device for transferring the magnetic recording medium on the transfer path of the magnetic recording medium. In a magnetic recording medium manufacturing apparatus provided with a vapor deposition device for forming a lubricant layer as a top coat layer on a ferromagnetic metal thin film layer by a vacuum vapor deposition method, the transfer device is such that the back surface of the magnetic recording medium is in close contact. The main roller that runs on the magnetic recording medium and a pass roller that runs in close contact with the ferromagnetic metal thin film layer side of the magnetic recording medium are provided with an electrode plate facing the outer circumference of the main roller. It is characterized in that a power supply for applying is provided.

Effect According to the present invention, by applying a voltage between the ferromagnetic metal thin film layer and the electrode plate, the energy of vapor deposition on the ferromagnetic metal thin film layer is increased, and as a result, aggregation of the lubricant particles is prevented. Further, when the lubricant particles reach the ferromagnetic metal thin film layer, they are firmly bonded to each other, and the lubricant is easily diffused by the action of the electrostatic force, so that a uniform lubricant layer can be formed. Therefore, the aggregated lubricant does not adhere to the roller or the like to promote the contamination of the apparatus, and the dropout as a recording / reproducing defect can be significantly reduced.

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

FIG. 1 shows an outline of a device configuration in an embodiment of the present invention. The basic structure of the magnetic recording medium manufactured in this embodiment is the same as that of the conventional one shown in FIG. 4, and in this embodiment, a PET film of 3 to 20 μm is used as the non-magnetic substrate 1, and 0.1 to
Ferromagnetic metal thin film layer 2 by oblique deposition of 0.2 μm Co-Ni
And a mixture of resin and carbon as a back coating layer 3 on the back surface for improving the running property of about 0.3 to 1 μm.
Applying.

In FIG. 1, reference numeral 21 is a magnetic recording medium before the formation of the lubricant layer 4, which is sent out to the area where the lubricant layer 4 is formed and has a tension of 500 mm.
It is controlled to 0.5 to 20 Kg by radiation. Reference numerals 22 and 24 denote pass rollers which rotate in close contact with the magnetic recording medium. Reference numeral 23 is 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 has a width of 500 mm and is continuously wound with a tension of 0.5 to 20 kg, and the taper tension can be controlled. Reference numeral 26 is an evaporation source, in which fatty acids, fatty acid esters, fatty acid amides, etc. are filled as lubricants, which are melted and vapor-deposited. Reference numeral 27 denotes a heat medium tank, which heats and melts the lubricant. Reference numeral 28 denotes a heat medium circulating device provided outside the vacuum tank, which controls the temperature of the heat medium and supplies the heat medium 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. At 30 an evaporation rate monitor detects the amount of evaporation of the lubricant particles and controls 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 is an electrode plate, and 33 is a power source provided outside the vacuum chamber, which applies a voltage between the ferromagnetic metal thin film layer 2 and the electrode plate 32 via the pass rollers 22 and 24, and has a capacity of 3000V. .

The operation of the method and apparatus for manufacturing the 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 while being energized from a pass roller or an unwinding or winding shaft. Further, the lubricant is heated and melted by the heat medium from the heat medium circulation device 28 to start evaporation, but the shutter 31 is opened at the time when the specified evaporation rate is reached, the lubricant particles reach the magnetic recording medium, and the lubricant layer 4 is formed. To be done. At this time, the ferromagnetic metal thin film layer 2 and the electrode plate 32
Since a voltage is applied between and, the vapor deposition and energy are improved, the aggregation of the lubricant particles is prevented, and the lubricant metal particles are firmly bonded to the ferromagnetic metal thin film layer 2, and the lubricant particles are uniformly distributed by the electrostatic force. And can form a homogeneous lubricant layer.

FIG. 2 shows that the nonmagnetic substrate 1
When the applied voltage is changed between the ferromagnetic metal thin film layer 2 and the electrode plate 32 when the width of the ferromagnetic metal thin film layer 2 is 500 mm, the thickness of the ferromagnetic metal thin film layer 2 is 0.15 μm, the main roller diameter is 1 m, and the forming speed is 30 m / min. Shows the change in the number of dropouts.

Note that V is used as a unit of the applied voltage on the horizontal axis of the graph of FIG.

The dropout number is 15 μs or more when a video signal is recorded and reproduced for 10 minutes 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 mm using a rotating cylinder type video tape recorder. It is the average value per minute of the number of times that the signal of 16 dB or more is omitted during the period.

As can be seen from the graph in Fig. 2, the applied voltage is 300 to 1
A remarkable reduction in the number of dropouts in the range of 200V was observed, and it is clear that practical use is possible in this range.

As described above, according to the present invention, a lubricant layer as a top coat layer is formed on a magnetic recording medium having a ferromagnetic metal thin film layer formed on a non-magnetic substrate by a vacuum deposition method to form an electrode plate and a metal thin film layer. By forming while applying a voltage in between, it is possible to reduce the aggregation of the lubricant while improving the film formation rate, and as a result, there is a particular effect that dropout as a recording / reproducing defect is significantly reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of the apparatus configuration in one embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the number of dropouts and an applied voltage in the case of a constant film formation rate, and FIG. 3 is a conventional method. FIG. 4 is a diagram showing the relationship between the number of dropouts and the film formation rate in FIG. 4, FIG. 4 is a sectional view showing the structure of a magnetic recording medium, and FIG. 5 is a diagram showing a method of manufacturing a conventional magnetic recording medium. 1 ... Non-magnetic substrate, 2 ... Ferromagnetic metal thin film layer, 4 ... Lubricant layer, 21 ... Magnetic recording medium, 22, 24 ... Pass roller, 23
...... Main roller, 25 ...... Magnetic recording medium with lubricant layer formed,
26 ... Evaporation source, 27 ... Heat medium layer, 28 ... Heat medium circulation device, 32
…… Electrode plate, 33 …… Power supply for applying potential.

Claims (2)

(57) [Claims] 1. A method in which a magnetic recording medium having a ferromagnetic metal thin film 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. An electrode plate is provided so as to face the magnetic recording medium, and a potential is applied between the electrode plate and the ferromagnetic thin film layer. 2. A transfer device for transferring a magnetic recording medium having a ferromagnetic metal thin film formed on a non-magnetic substrate in a predetermined direction,
A manufacturing apparatus of a magnetic recording medium, comprising: a vapor deposition apparatus for forming a lubricant layer as a top coat layer on the ferromagnetic metal thin film layer by a vacuum vapor deposition method on a transport path of the magnetic recording medium. A back surface of the magnetic recording medium is in close contact with the main roller and a ferromagnetic metal thin film layer side of the magnetic recording medium is in close contact with a pass roller, and an electrode plate is provided facing the outer periphery of the main roller. Further, a magnetic recording medium manufacturing apparatus is provided with a power source for applying a voltage to the electrode plate and the outer periphery of the pass roller.