JPH02128323A - Method and device for producing magnetic recording medium - Google Patents

Abstract

PURPOSE:To decrease the coagulation of a lubricant, while improving a film forming speed by providing an electrode plate so as to be opposed to a magnetic recording medium which runs, and impressing the voltage between this electrode plate and a ferromagnetic metallic thin film layer. CONSTITUTION:On a magnetic recording medium obtained by forming a ferromagnetic metallic thin film layer 2 on a non-magnetic substrate 1, a lubricant layer 4 being a top coat layer is formed by a vacuum deposition method, while impressing a voltage between an electrode plate 32 and the metallic thin film layer 2. In this case, when a voltage is impressed between the metallic thin film layer 2 and the electrode plate 32, energy of vapor deposition on the ferromagnetic metallic thin film layer 2 becomes high, and as a result, the coagulation of lubricant grains is prevented. Also, when the lubricant grains reach the ferromagnetic metallic thin film layer 2, they are coupled firmly, and also, by an action of electrostatic force, the lubricant is diffused easily, and a homogeneous lubricant layer 4 is formed. In such a way, while improving a film forming speed, the coagulation of the lubricant is decreased, and as a result, the drop-out being a recording and reproducing defect is decreased remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method and apparatus for manufacturing a ferromagnetic metal thin film type magnetic recording medium, and in particular, to improve practical performance, a lubricant layer is vacuum-deposited as a top coat layer after forming a metal thin film layer. The present invention relates to a method for manufacturing a magnetic blade recording medium in which a homogeneous lubricant layer is formed by a method and a manufacturing apparatus.

Conventional technology Co, Ni, Fe, or alloys containing these as main components are formed into polyester films, polymer films such as polyimide films, non-magnetic metal substrates, etc. using vacuum film forming methods such as vacuum evaporation, sputtering, and ion grating. A ferromagnetic metal thin film magnetic recording medium formed on a substrate can dramatically improve the recording density compared to conventional coated magnetic recording media, but there are certain prerequisites for achieving this high recording density. Therefore, it is important to reduce recording and reproducing defects as much as possible, as well as to reduce spacing loss between the magnetic head and the recording medium as much as possible, and the recording medium must also have durability. To solve these problems, one method of forming a lubricant layer as a top coat after forming a metal thin film layer is to form a lubricant such as fatty acid, fatty acid ester, fatty acid amide, etc. by vacuum deposition.

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

FIG. 4 shows a cross-sectional structure of a magnetic recording medium, and FIG. 6 shows an outline of an apparatus configuration used in a conventional method of manufacturing a magnetic recording medium.

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

In FIG. 6, reference numeral 11 denotes a magnetic recording medium before the formation of a top coat, which is wound into a roll.

12.14 is a pass roller, 13 is a main roller,
The magnetic recording medium is conveyed closely. 16 is a magnetic recording medium on which a top coat has been formed and is continuously wound. 16 is an evaporation source filled with a lubricant, and 17 is a heat medium tank that indirectly heats and melts the lubricant in the evaporation source 16 to evaporate it. 1
8 is a heat medium circulation device, which controls the temperature of the heat medium and supplies the heat medium to the heat medium tank 17, and is provided outside the vacuum tank. Reference numeral 19 denotes an adhesion prevention plate, which is provided to prevent evaporated lubricant particles from contaminating the magnetic recording medium in the vacuum chamber or the component parts that convey it. 2
0 is an evaporation rate monitor, which is used to detect the amount of evaporation and adjust the temperature of the heat medium in the heat medium circulation device 18.

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

When forming the ferromagnetic metal thin film layer 2 and forming the lubricant layer 4 on the non-magnetic substrate by vacuum evaporation, first, the lubricant is applied to the evaporation source 1.
The lubricant layer 4 is melted in step 6, and when a specified amount of evaporation is reached, the substrate is transported and a lubricant layer 4 is formed as a top coat.

Problems to be Solved by the Invention However, when forming a lubricant layer as a top coat using the conventional vacuum evaporation method described above, if the evaporation rate of the lubricant is increased in order to improve the film formation rate, the lubricant will coagulate and become homogeneous. It becomes impossible to form a lubricant layer. In addition, some of the aggregated lubricant adheres to the rollers, etc. inside the device, which not only promotes contamination of the device, but also contaminates the magnetic head, rotating cylinder, tape running post, etc. during recording and playback with a video tape recorder. However, since dropouts increase as recording/reproducing defects, there is a problem in that it becomes difficult to increase the film formation rate.

In view of the above-mentioned problems, the present invention provides a method and apparatus for manufacturing a magnetic recording medium using a vacuum evaporation method, which improves the film formation rate and reduces aggregation of lubricant.

Means for Solving the Problems In order to solve the above problems, the method for manufacturing a magnetic recording medium of the present invention consists of running a magnetic recording medium in which a ferromagnetic metal thin film is formed on a non-magnetic substrate in a fixed direction, and placing a top layer on top of the magnetic recording medium. In a method of continuously forming a lubricant layer as a coating by vacuum evaporation, an electrode plate is provided opposite the running magnetic recording medium, and a potential is applied between the electrode plate and the ferromagnetic metal thin film layer. It is characterized by

The apparatus for manufacturing a magnetic recording medium of the present invention further includes a transport device for transporting a magnetic recording medium in which a ferromagnetic metal thin film layer is formed on a non-magnetic substrate in a fixed direction, and a A manufacturing apparatus for a magnetic recording medium, which includes a vapor deposition device for forming a lubricant layer as a top coat layer on a ferromagnetic metal thin film layer by vacuum vapor deposition, wherein the transfer device is configured such that the back surface of the magnetic recording medium is in close contact with the magnetic recording medium. It consists of a 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.An electrode plate is provided opposite the outer periphery of the main roller, and a voltage is applied between the electrode plate and the outer periphery of the bus roller. According to the present invention, the energy of vapor deposition on the ferromagnetic metal thin film layer is increased by applying a voltage between the ferromagnetic metal thin film layer and the electrode plate. As a result, agglomeration of lubricant particles is prevented. Further, when the lubricant particles reach the ferromagnetic metal thin film layer, they are firmly bonded, and the lubricant particles are easily diffused by the action of electrostatic force, forming a homogeneous lubricant layer.

Therefore, the aggregated lubricant does not adhere to the rollers or the like and promote contamination of the apparatus, and dropouts as recording/reproducing defects can be significantly reduced.

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

FIG. 1 shows an outline of the device configuration in an embodiment of the present invention. The basic structure of the magnetic recording medium manufactured in this example is the same as that of the conventional one shown in FIG.
．． A ferromagnetic metal thin film layer 2 is formed by oblique evaporation of Go-Ni with a thickness of 1 to 0.2 μm, and a mixture of resin and carbon is coated on the back side with a thickness of approximately 0.3 to 1 μm as a back coating layer 3 to improve running properties. It is being applied.

In FIG. 1, 21 is a magnetic recording medium before the formation of the lubricant layer 4, and is sent to the area where the lubricant layer 4 is formed, and its tension is 600.
It is controlled to be 0.5-20-f corresponding to fl radiation. 22
．． A pass roller 24 rotates in close contact with the magnetic recording medium.

23 is a main roller that moves the magnetic recording medium at a constant speed (0, 1 to 2
00m/min). 26 is a magnetic recording medium on which a lubricant layer 4 has been formed, and the width is 0.6 equivalent to 5 oots width.
It is continuously wound with a tension of ~20 Kgf, and the Taber tension can also be controlled. Reference numeral 26 denotes an evaporation source, which is filled with a fatty acid, a fatty acid ester, a fatty acid amide, etc. as a lubricant, and is melted and vapor deposited. A heating medium tank 27 heats and melts the lubricant. 28 is a heat medium circulation device provided outside the vacuum chamber, which controls the temperature of the heat medium and supplies the heat medium to the heat medium tank 27. Reference numeral 29 denotes an anti-adhesion plate, which prevents evaporated lubricant particles from contaminating the magnetic recording medium in the vacuum chamber or the component parts that convey it. It is made of material. An evaporation rate monitor 30 detects the amount of evaporation of lubricant particles and controls the temperature of the heat medium in the heat medium circulation device 28.

A shutter 31 is opened after a predetermined evaporation rate is reached, and evaporation begins on the substrate. 32 is an electrode plate, 33 is a power supply provided outside the vacuum chamber, which applies voltage between the ferromagnetic metal thin film layer 2 and the electrode plate 32 via pass rollers 22, 24, and has a capacity of 3000V. . - The operation of the magnetic recording medium δ production and production apparatus of the present invention constructed as described above will be explained with reference to FIG.

In order to form the lubricant layer 4 as a top coat on the ferromagnetic metal thin film layer 2, the magnetic recording medium before the lubricant layer 4 is formed is continuously brought into close contact with the main roller while being energized from the pass roller or the unwinding or winding shaft. being sent. The lubricant is heated and melted by the heat medium from the heat medium circulation device 28 and starts to evaporate.
is released, and the lubricant particles reach the magnetic recording medium and form the lubricant layer 4.
is formed. At this time, since a voltage is applied between the ferromagnetic metal thin film layer 2 and the electrode plate 32, the deposition energy is improved, preventing agglomeration of lubricant particles and firmly bonding with the ferromagnetic metal thin film layer 2. Further, the lubricant particles are uniformly diffused into the metal thin film layer by electrostatic force, and a homogeneous lubricant layer can be formed.

FIG. 2 shows the conditions for forming the lubricant layer 4: the width of the nonmagnetic substrate 1 is 5ootar, and the thickness of the ferromagnetic metal thin film layer 2 is 0.16μ.
Figure 3 shows the change in the number of dropouts when the voltage applied between the ferromagnetic metal thin film layer 2 and the electrode plate 32 is changed in the case where the main roller diameter is 1 m and the forming speed is 30 m/min.

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

The number of dropouts was determined using a rotating cylinder type video tape recorder with a tape width of 8 ff and a relative speed of 3.8.
m/S, tape speed 1.4 cIn/s, tape speed 1.4 cIn/s) When a video signal is recorded and reproduced for 10 minutes at a rack pitch of about 20 InI, it is the average value per minute of the number of times the signal is deleted for 1 sdB or more for 15 μs or more.

As can be seen from the graph in Figure 2, the applied voltage is 300~
A remarkable reduction in the number of dropouts was observed in the range of 1200V, indicating that practical use is possible within this range.

Effects of the Invention As described above, according to the present invention, a lubricant layer as a top coat layer is applied to a magnetic recording medium in which a ferromagnetic metal thin film layer is formed on a nonmagnetic substrate by a vacuum evaporation method. By forming the film while applying a voltage between the two, it is possible to increase the film formation speed and reduce the aggregation of the lubricant.
As a result, it has the unique effect of significantly reducing dropouts as recording/reproduction defects.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an overview of the equipment configuration in an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the number of dropouts and the applied voltage when the deposition rate is constant, and Fig. 3 is a diagram showing the conventional method. FIG. 4 is a cross-sectional view showing the structure of a magnetic recording medium, and FIG. 5 is a diagram showing a conventional magnetic recording medium product. 1...Nonmagnetic substrate, 2...Ferromagnetic metal thin film layer, 4...Lubricant layer, 21...Magnetic recording medium, 22°24°゛°°°Pass roller, 23...
... Main roller, 26 ... Magnetic recording medium with lubricant layer formed, 26 ... Evaporation source, 27 ...
... Heat medium layer, 28 ... Heat medium circulation device, 321.
101. Electrode plate, 33. Old power source for applying potential. Agent's name: Patent attorney Shigetaka Awano and one other person. r

Claims (2)

[Claims] (1) In 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 as a top coat thereon by a vacuum evaporation method, the running magnetic 1. A method of manufacturing a magnetic recording medium, comprising: providing an electrode plate facing the recording medium; and applying a potential between the electrode plate and the ferromagnetic metal thin film layer. (2) A transport device for transporting a magnetic recording medium in a fixed direction, in which a ferromagnetic metal thin film layer is formed on a nonmagnetic substrate, and a vacuum vapor deposition device on the ferromagnetic metal thin film layer on the transport path of the magnetic recording medium. and a vapor deposition device for forming a lubricant layer as a top coat layer by a method, the transfer device includes a main roller that runs with the back side of the magnetic recording medium in close contact with the magnetic recording medium, It consists of a pass roller that runs in close contact with the ferromagnetic metal thin film layer side of the medium, an electrode plate is provided opposite to the outer periphery of the main roller, and a power source is further provided to apply voltage to the electrode plate and the outer periphery of the pass roller. Features: Magnetic recording media manufacturing equipment.