JPH02128321A - Method and device for producing magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent an attachment at the time of forming a protective layer from being transferred to the back coating surface and from adhering to a head and to reduce an output fluctuation and loading of the head by forming a metallic thin film of a magnetic recording medium, and thereafter, forming a lubricant layer immediately after forming a protective layer on a ferromagnetic metallic thin film. CONSTITUTION:Immediately after forming a protective layer 4 on a magnetic recording medium by a plasma CVD method, a lubricant layer 5 is formed by vacuum deposition. Accordingly, before the magnetic recording medium is wound, the protective layer 4 is covered with the lubricant layer 5, and molecules of the protective layer 4 are wrapped up in the lubricant and hold a stable state. In such a way, an attachment generated at the time of forming the protective layer is scarcely transferred to the back coating surface 3 at the time of winding, and it does not adhere to a head either, therefore, an output variation and loading of the head are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a ferromagnetic metal thin film type magnetic recording medium, and in particular, to greatly reduce defects in a protective layer and a top coat layer provided after forming a magnetic layer to improve practical performance. The present invention relates to a method and apparatus for manufacturing a magnetic recording medium.

Conventional technology Go, Ni, Fe or alloys containing these as main components,
A ferromagnetic metal thin film magnetic recording medium is formed on a substrate made of a polymer film such as a polyimide film or a non-magnetic metal by a vacuum deposition method such as a vacuum evaporation method, a sputtering method, or an ion blating method. It is possible to dramatically improve recording density compared to conventional coated magnetic recording media.

By the way, as a condition for achieving this high recording density, it is important to reduce recording/reproduction defects as much as possible, as well as to reduce spacing loss between the magnetic head and the magnetic recording medium as much as possible. It is also necessary to have durability. Conventionally, in order to satisfy these conditions, it has been known to form a protective layer after forming the magnetic layer and further provide a lubricant layer as a top coat layer.

Figure 4 shows a cross section of a magnetic recording medium on which a protective film is formed using a conventional plasma CVD method and a lubricant layer is formed using a wet coating method, where 1 is a substrate and 2 is a ferromagnetic metal thin film layer formed using a vacuum film forming method. , 3 is a back coating layer, 4 is a protective layer formed by a plasma CVD method, and 6 is a lubricant layer formed by a wet coating method.

An example of the above-mentioned conventional magnetic recording medium manufacturing method and manufacturing apparatus will be described below with reference to FIGS. 4 and 6.

First, an apparatus for applying the protective layer 4 using the conventional plasma CVD method will be explained based on FIG. 6. 10a is a magnetic recording medium before the formation of the protective layer 4, and the feeding roller 1
It is wrapped around 1. Reference numeral 12 and 14 denote pass rollers, which rotate in contact with the ferromagnetic thin film layer 2 of the magnetic recording medium 1o. Reference numeral 13 denotes a main roller insulated from the main body of the apparatus, which applies a voltage between the ferromagnetic metal thin film layer 2 and conveys it while keeping it in close contact with the ferromagnetic metal thin film layer 2. A winding roller 16 continuously winds up the magnetic recording medium 1ob on which the protective layer 4 has been formed. 16 is a nozzle for plasma generation, 17 is an electrode, 1
8 is a gas inlet, 19 is a plasma power source, and these various components 16 to 19 form a processing unit for forming the protective layer 4.

A bias power source 40 applies a voltage between the main roller 13 and the ferromagnetic metal thin film layer 2 of the magnetic recording medium 10, and is provided outside the vacuum chamber together with the plasma power source 19.

Next, a method of manufacturing a magnetic recording medium by a conventional plasma CVD method using the apparatus configured as described above will be explained.

The magnetic recording medium 101L, which has not been formed with the protective layer 4 and is fed out from the feeding roller 11, passes through the pass roller 12, and then
With a voltage applied between the main roller 13 and the ferromagnetic metal thin film layer 2, it is continuously fed in close contact with the main roller 13. On the other hand, the ion current of the plasma for forming the protective layer 4 is connected to the reaction gas from the gas inlet 18 and the plasma power source 19.
The plasma generated by the applied voltage is sent from the plasma nozzle 16 and reaches the ferromagnetic metal thin film layer 2 of the magnetic recording medium 10a, forming the protective layer 4. The magnetic recording medium 10b on which the protective layer 4 is formed passes through the winding roller 14 and is then wound onto the winding roller 16.

The magnetic recording medium on which the protective layer 4 has been formed by the plasma CVD method is once removed from the plasma CVD apparatus, and a lubricant layer is formed in a wet coating apparatus.

Problems to be Solved by the Invention However, in the above-mentioned conventional method, active species, ions, etc. leaked from the plasma nozzle during the formation of the protective layer 4 weakly adhere to the ferromagnetic metal thin film layer 2 of the magnetic recording medium 10a, and are difficult to wind up. The back coating will adhere to the surface when exposed. Also, active species leaked from the nozzle.

Ions and the like are scattered throughout the vacuum chamber and adhere to the magnetic recording medium. These deposits have weak adhesion to the magnetic recording medium, and may be transferred or dropped during winding after the lubricant layer is formed or when running on a VTR. In particular, during playback on a VTR, this deposit also adheres to the head. However, this not only causes output fluctuations but also causes head clogging, resulting in serious defects as a magnetic recording medium.

In view of the above-mentioned problems, the present invention reduces deposits with weak bonding strength due to leakage of active species and ions when forming a protective layer, and in particular, reduces transfer to the back coating surface during winding.
Reduces head adhesion during playback on VTRs, reduces output fluctuations,
The present invention aims to provide a method and apparatus for manufacturing a magnetic recording medium in which head clogging is significantly reduced.

Means for Solving the Problems In order to solve the above problems, the method for manufacturing a magnetic recording medium of the present invention is to run a magnetic recording medium in which a ferromagnetic metal thin film layer is formed on a non-magnetic substrate in a fixed direction, plasma CV
Particularly, the apparatus for producing a magnetic recording medium of the present invention is characterized in that a protective layer is formed by the D method, and immediately thereafter a lubricant layer as a top coat layer is continuously formed by a vacuum evaporation method. a transport device for forming a ferromagnetic metal thin film layer on a substrate and transporting the magnetic recording medium in a fixed direction; and a plasma forming a protective layer on the ferromagnetic metal thin film layer on the transport path of the magnetic recording medium. The present invention is characterized in that a CVD device and a vacuum evaporation device that continuously forms a lubricant layer as a top coat layer immediately after forming the protective layer are arranged behind the plasma CVD device on the transfer path.

According to the present invention, by forming a lubricant layer by vacuum deposition immediately after forming a protective layer on a magnetic recording medium by plasma CVD, the protective layer is covered with the lubricant layer before the magnetic recording medium is wound. Since the molecules of the protective layer are wrapped in the lubricant and kept in a stable state, the deposits generated during the formation of the protective layer are
Since it is hardly transferred to the back coating surface during winding and does not adhere to the head, output fluctuations and head clogging are prevented.

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 20 manufactured in this example is the same as the conventional one shown in FIG.
] The ET film is used as the substrate 1, and the surface has a thickness of 0.1 to 0.2μ.
The magnetic recording medium 20 has a ferromagnetic metal thin film layer formed by oblique evaporation of a Go-Ni alloy of m and a back coating layer 3 made of a mixture of resin and carbon on the back surface to improve running properties. A protective layer 4 and a lubricant layer 5 are formed on the ferromagnetic metal thin film layer 2 .

In FIG. 1, 20& is a magnetic recording medium before the formation of the protective layer 4 and the lubricant layer 6, and it is wound around the feeding roller 21, and from this feeding roller 21, the tension is 60°.
It is controlled and sent out at O, S to 20Kof in terms of 0H width. 22.24 is a pass roller and magnetic recording medium 2
Rotates in close contact with 0. 23 is a main roller, and a dielectric film is provided on the surface thereof. The roller 23 also has a bias power source 30 connected to its main body.
While a voltage of 3 KV is applied, the rotation is controlled so that the magnetic recording medium 2o is transported at a constant speed (0.1 to 2 oom/min). 26 is a roller that continuously winds up the magnetic recording medium 20b after the protective layer 4 and lubricant layer 6 have been formed, and the tension is controlled to 0.5 to 20 to f in terms of 500ff width, and taper tension can also be controlled. be. 26 is a plasma nozzle for forming the protective layer 4, and 27 is a plasma generation electrode connected to a plasma generation power source 29. This plasma generation power source 29 can apply a voltage with an effective value of 0.06 to 7 KV using DC, MuCRF, or a combination thereof.

28 is a gas inlet port that injects reactive gas such as H2Mr, 0M system, etc. or vaporized gas such as ketone system, alcohol system, etc.
．． It is introduced at a partial pressure of 5 to 0.001 Torr. Further, numeral 31 is an evaporation source and is filled with a fatty acid, a fatty acid ester, a fatty acid amide, etc. as a lubricant. 32 is the evaporation source 31
This is an evaporation source heating device for melting and vaporizing lubricant, and its heating intensity is controlled by detecting the temperature of the evaporation source. Reference numeral 33 denotes an adhesion prevention plate, which prevents evaporated lubricant particles from contaminating the magnetic recording medium in the vacuum chamber or the component parts that convey it. An evaporation rate monitor 34 detects the amount of evaporation of lubricant particles and controls the temperature of the evaporation source. A shutter 36 is opened after a predetermined evaporation rate is reached, and the lubricant starts to be deposited on the protective layer of the magnetic recording medium.

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

The magnetic recording medium 201L before the formation of the protective layer and the lubricant layer is as follows:
Main roller 2 to which voltage is applied from bias power supply 30
3 on the back side of the ferromagnetic metal thin film layer 2, and is continuously conveyed from the feeding roller 21 toward the winding roller 26. The ionic current of the plasma for forming the protective layer 4 is generated by the reactive gas from the gas inlet 28 and the voltage applied from the plasma power supply 29, and the plasma ion current for forming the protective layer 4 is
The protective layer 4 is deposited upon reaching the ferromagnetic metal thin film layer 2 of the magnetic recording medium 20 & located opposite the forming plasma nozzle 26 . A lubricant layer 6 is formed immediately after the main roller 23 on which the protective layer 4 is formed.

This lubricant for forming the lubricant layer 5 is filled in an evaporation source 31, heated and melted by a heating device 32, and when a prescribed evaporation rate is reached by an evaporation rate monitor 34, a shutter 36 is released and the ferromagnetic metal thin film is Immediately after forming the protective layer 4 on the layer 2, the lubricant layer 5 is formed. By forming the lubricant layer immediately after forming the protective layer as described above, the protective layer 4 is covered with the lubricant layer 6 before the magnetic recording medium 20 is wound around the take-up roller 25. The protective layer 4 and the lubricant layer 6 can be formed without almost any deposits caused by leakage of active species or ions being transferred to the surface of the back coating layer 3.

Next, the effects of the above-described embodiment will be explained using FIGS. 2 and 3.

In both FIG. 2 and FIG. 3, a diamond-like carbon film with a thickness of about 100 mm is formed as the protective layer 4 by the method of the present invention and the conventional example at a gas introduction pressure of o and an applied voltage of 1 Torr, which is IKV in total with the bias. This figure shows the head clogging and the degree of head contamination when recording and reproducing using a video tape recorder was performed on a magnetic recording medium 10.20 in which stearic acid was provided as a lubricant layer to a thickness of about 30 mm.

As a specific condition, magnetic recording media 1o and 20 with a width of 8 mm were run at a speed of about 14 H/sec for a period of about 90 minutes at a relative speed of 3. The video signal was recorded with a rotating cylinder type video tape recorder at am/sec and a track pitch of approximately 20 μm.
This shows data after approximately 200 hours of playback.

FIG. 2 shows the integrated value of head clogging time, and FIG. 3 shows the degree of contamination of the head. The head clogging time is the time during which the output drops by more than edB, and the degree of head contamination is an index of the amount of lubricant layer 6, back coating layer 3, etc. that is missing from the magnetic recording medium and remains on the head surface or around the head. It has become.

From FIG. 2, it was confirmed that the head clogging after 100 hours or more was significantly reduced (less than 1/1 o) and that the practical limit could be cleared with a margin. Furthermore, in magnetic recording media manufactured by the conventional method, output fluctuations appear around the time when head clogging occurs and increases, and the amplitude increases as the number of runs increases.

From FIG. 3, head contamination is saturated after a few runs of 1o and is extremely stable thereafter. However, in the case of the conventional method, the number of runs increased to about 100 times and has been increasing and decreasing repeatedly since then.

As is clear from the above experimental results, according to the present invention,
The deposits that adhered to the protective layer 4 during the film formation are transferred to the back coating surface during winding, and when running on a video tape recorder, this gradually breaks off and adheres to the head, eventually leading to head clogging. Since this phenomenon is prevented, large output fluctuations do not occur within practical limits.

In this case, the reason why the deposits on the protective layer are prevented from being transferred or missing is that the deposits are thought to have a very small number of molecules, so they are wrapped in the lubricant during the formation of the lubricant layer.
This is thought to be because it remains in a stable state.

Effects of the Invention As described above, according to the present invention, after forming a metal thin film of a magnetic recording medium, a lubricant layer is formed on a ferromagnetic metal thin film immediately after the protective layer is formed, thereby reducing the backing of deposits during the formation of the protective layer. It can prevent transfer to the coating surface and adhesion to the head, and as a result, during recording and playback in video tape recorders, head clogging is greatly reduced, and problematic output fluctuations are eliminated, resulting in good recording and playback characteristics. can be obtained over a longer period of time.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an overview of the device configuration in an embodiment of the present invention, Fig. 2 is a comparison diagram between the conventional example and the embodiment of the present invention regarding the number of runs and head clogging, and Fig. 3 is the number of runs. FIG. 4 is a cross-sectional view showing the structure of a magnetic recording medium, and FIG. 6 is a schematic diagram showing an apparatus for manufacturing a magnetic recording medium using a conventional protective layer forming method. DESCRIPTION OF SYMBOLS 1...Nonmagnetic substrate, 2...Ferromagnetic metal thin film layer, 4...Protective layer, 6...Lubricant layer, 2o...・Magnetic recording medium, 21...Feeding roller, 22.24...Pass roller, 2
3...Main roller, 26...Take-up roller, 27...Plasma generation electrode, 28
・・・・・・Gas inlet, 29°old°“Plasma power supply, 31・・・Evaporation source, 32・・・Heating device. Name of agent: Patent attorney Shigetaka Awano et al. 1 Famous confectionery diagram O book fullness awakening?

Claims (2)

[Claims] (1) A magnetic recording medium with a ferromagnetic metal thin film layer formed on a nonmagnetic substrate is run in a fixed direction, and a plasma CV
A method for manufacturing a magnetic recording medium, which comprises forming a protective layer by method D, and immediately thereafter continuously forming a lubricant layer as a top coat layer by vacuum evaporation. (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 non-magnetic substrate, and a protection device on the ferromagnetic metal thin film layer on the transport path of the magnetic recording medium. A plasma CVD device that forms a layer and a vacuum evaporation device that continuously forms a lubricant layer as a top coat layer immediately after forming this protective layer are arranged behind the plasma CVD device on the transfer route. A magnetic recording medium manufacturing apparatus characterized by: