JP3232541B2 - Method and apparatus for manufacturing magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for manufacturing a magnetic recording medium.

[0002]

2. Description of the Related Art A magnetic tape is most widely used as a magnetic recording medium, and has a structure in which a magnetic layer is provided on one surface of a base film. The magnetic layer is a layer in which magnetic particles are dispersed in a binder resin, and is formed by applying a magnetic paint on a base film and drying it.

[0003] The application of the magnetic paint is carried out by supplying the magnetic paint to the base film surface by, for example, a gravure roll in the course of the transport while transporting the base film.

On the other hand, a magnetic recording medium such as a magnetic tape records a large amount of information in a narrow area. Therefore, if dust adheres to a base film before applying a magnetic paint, the following problem occurs.

[0005] (1) The electromagnetic conversion characteristics are deteriorated at the portion where the dust adheres, and dropout is caused extremely. Also, the spacing loss during recording / reproduction increases.

(2) Adhered dust extremely wears the magnetic head, changes the size of the extremely small magnetic gap, and deteriorates the electromagnetic conversion characteristics.

(3) The life of a recording / reproducing apparatus (deck) may be shortened due to the wear described above.

(4) In the case of a magnetic tape, friction at the tape guide portion becomes large, and the tape running speed may not be uniform.

(5) The S / N ratio decreases.

As means for preventing the adhesion of dust, freon washing, an adhesive roller, and a web cleaner (a device for blowing ionized air, brushing and removing under reduced pressure) are employed. Among these, the method using an adhesive roller can be performed at low cost, and in the printing industry, in particular, the adhesive roller is used for removing paper dust.

Therefore, it is conceivable to remove the adhered dust by bringing an adhesive roller into contact with the base film before applying the magnetic paint. However, in recent high-density magnetic tapes, the surface of the base film is extremely smoothed by reducing the compounding amount of the filler, and is easily charged. Therefore, the magnetic tape is charged by the contact with the adhesive roller, and the amount of static electricity due to the charging is increased, which causes a secondary dust adhesion, which is a very troublesome situation. Furthermore, the stability of high-speed running deteriorates due to the static electricity.

The above problems exist not only when forming the magnetic layer but also when forming the back coat layer and the intermediate layer.

If the coating operation is performed in a clean room, the above-mentioned problem can be solved. However, this requires an enormous amount of equipment cost, resulting in a significant cost increase. To date, no effective means for solving the above problem economically has been found yet.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a high quality and highly reliable magnetic recording medium which effectively and economically prevents dust from adhering. It is an object of the present invention to provide a manufacturing method, an apparatus therefor, and a conductive adhesive roller used for these.

[0015]

In order to achieve the above object, the present invention has the following arrangement.

According to a first aspect of the present invention, when manufacturing a magnetic recording medium having a magnetic layer provided on a substrate, the method includes a step of applying a magnetic recording medium constituent layer. The present invention relates to a method for manufacturing a magnetic recording medium, wherein a conductive adhesive roller having an adhesive layer laminated on a core material is brought into contact with the substrate side at a predetermined angle alone.

A second invention is an apparatus for manufacturing a magnetic recording medium having a magnetic layer provided on a substrate, comprising a substrate transporting means and a coating material for forming a magnetic recording medium constituent layer on the substrate. A conductive adhesive roller formed by laminating a plurality of conductive adhesive layers on a core material alone at a predetermined angle on the substrate side. The present invention relates to a magnetic recording medium manufacturing apparatus which is brought into contact with a magnetic recording medium.

In the manufacturing apparatus of the present invention, it is preferable that the charge removing means for removing charge from the substrate is provided just before the coating means.

Further, it is preferable that the conductive adhesive roller is disposed on the upstream side of the charge removing means.

In the manufacturing method of the present invention, it is preferable that the angle of each tangent at the entrance point and the exit side contact point of the base with respect to the conductive adhesive roller is 90 to 160 degrees.

The conductive pressure-sensitive adhesive roller used in the present invention is preferably formed by laminating a plurality of pressure-sensitive adhesive layers in which conductive particles are dispersed in a pressure-sensitive adhesive material around a core material.

[0022]

Embodiments of the present invention will be described below.

FIG. 8 is an enlarged sectional view showing an example of the magnetic recording medium.

That is, the magnetic tape has a magnetic recording layer (magnetic layer) 32 containing a magnetic powder, a binder and the like on one surface of a non-magnetic base film 31. Further, a back coat layer 33 mainly composed of a non-magnetic powder and a binder may be provided on the other surface as indicated by a dashed line. Further, the undercoat layer 34 of the magnetic layer 32 may be provided as shown by a two-dot chain line. Such a layer configuration is a layer configuration common to various magnetic tapes such as for video, audio, and digital audio tape recorder (DAT).

FIG. 1 is a schematic front view showing the procedure for providing a magnetic layer on a base film.

The base film 1A before the magnetic layer is provided is wound around the payout shaft 11, and the magnetic tape 1 on which the magnetic layer is adhered.
B is wound around a winding shaft 12. A guide roller 2 and a conductive adhesive roller 1 are provided between the feeding shaft 11 and the winding shaft 12.
3, a guide roller 2, 2, a gravure roll 5 pressed by the backup roll 3, a guide roller 2, 2, a drying unit 8, and a calendar processing unit 9 including a five-stage roll are arranged in this order.

When the take-up shaft 12 is rotated by a driving device (not shown), the pay-out shaft 11 follows, and the coated base film 1A wound therearound is guided and conveyed by each guide roller 2 to be conveyed. The dust adhering to the adhesive roller 13 and adhering thereto adheres to the conductive adhesive roller 13 and is removed from the base film 1A. The structure of the conductive adhesive roller 13 will be described later in detail with reference to FIGS.

The magnetic paint 4 accommodated in the container 7 is supplied to one side of the base film 1A which is guided between the two rolls 3 and 5 by the gravure roll 5 which rotates while being pressed by the backup roll 3, and is applied thereto. Applied.

Immediately before the backup roll 3, a static eliminator (for example, Achilles Non-Spark or Celmec) 18 is disposed in a non-contact manner in opposition to the base film 1A. It is designed to eliminate static electricity.

The gravure roll 5 is provided with a layer-thickness regulating blade 6 opposed to the gravure roll 5, so that the thickness of the magnetic paint supplied by the gravure roll 5 is kept constant and the thickness of the coating film is uniform. It is made to become. The backup roll 3 is preferably made of a conductive elastic body (for example, conductive rubber) to release static electricity.

The base film 1B having one surface coated with the magnetic paint is sent to the drying unit 8 via the guide rollers 2 and 2, and a magnetic layer formed by drying the magnetic paint is formed on one surface. For drying, for example, a steam heating method can be adopted.

Base film 1B on which magnetic layer is formed
Is guided to a calendar processing section 9, passes sequentially through rolls 10 provided in five stages, smoothes the surface of the magnetic layer, and is wound around a winding shaft 12.

Each guide roller 2 is made of aluminum alloy or steel.

FIG. 2 is a perspective view showing the relationship between the conductive adhesive roller and the base film, FIG. 3 is a front view of the conductive adhesive roller, and FIG. 4 is an enlarged partial sectional view of FIG.

About 10 layers of a conductive adhesive layer 15 having a thickness of 1 to 2 mm are laminated around an iron round bar core material 14, and a conductive adhesive roller
13 are configured. The conductive adhesive layer 15 is made of an ethylene-propylene (EP) -based or isobutylene (IIR) -based rubber 16.
Is blended with carbon black 17 (Ketjen black (trade name) manufactured by Columbia Carbon Co., Ltd. in this example) as a rubber black, and has a resistance value of 10 ⁴ while retaining adhesiveness.
A semiconductivity is given as ~ 10 ⁷ Ω.

The shaft 14a of the core shaft 14 is supported by a bearing (not shown) so that the conductive adhesive roller 13 is rotated by friction as the base film 1A runs. The shaft 14a is connected to a ground circuit.

The following experiment was conducted using the conductive adhesive roller having the above structure.

As shown by imaginary lines in FIG. 3, the angles formed by the tangents of the base film 1A to the conductive adhesive roller 13 at the entry-side contact point and the discharge-side contact point of the base film 1A (that is, immediately before and after the conductive adhesive roller 13). Is an angle formed by the extension of the surface of the base film 1A, and this angle is hereinafter referred to as an included angle.)
Set to 20 degrees. As the base film 1A, a polyester base film having a thickness of 14 μm used for a magnetic tape for video was used, and the running speed was set to 250 m / min. The diameter of the conductive adhesive roller 13 is 100 mm, and the peripheral speed is about 250 m /
Minutes.

With respect to the base film passed through the conductive adhesive roller, the amount of charge and the impression of the impression due to the adhesion of dust (300 mm ×
The number of visual impressions in the area of 300mm)
A sample that did not cause vibration, a sample with a small amount of charge, and a sample with a small amount of the above-mentioned impression were evaluated as ○, a sample with a large amount was evaluated as x, and a sample intermediate between the two was evaluated as Δ.

The measurement of the charge amount was performed using a static electricity meter KS-533 manufactured by Kasuga Electric Co., Ltd. at a position immediately after the base film was separated from the conductive adhesive roller.

The hardness of the conductive pressure-sensitive adhesive layer, the electric resistance between the conductive adhesive layer and the core material, and the experimental results are as shown in Table 1 below.
Table 1 also shows, for comparison, similar results obtained by using an adhesive roller that has not been subjected to a treatment for imparting conductivity (compounding carbon black).

[0042]

From Table 1, it can be seen that the embodiment using the conductive adhesive roller is different from the comparative example using a mere adhesive roller.
It can be seen that when the electric resistance value is less than 10 ⁶ order, the charge amount is reduced to 以上 or more, and the properties as a base film for a magnetic tape are greatly improved.

In the magnetic tapes manufactured in the above-described Examples 1 and 2 and Comparative Examples 1 to 3 by the apparatus shown in FIG.
RF power and magnetic head wear were examined. The outline of the measurement in this survey is as follows.

<Dropout (15 μsec)> A 100% white level signal is recorded, and the video head-up output attenuation during reproduction is 20 dB, the duration is 5 μsec. (VH01CZ, manufactured by Counter Shiba Sokusha Co., Ltd.) and determined as an average value per minute.

<RF Output> The RF output at 7 MHz was measured using a VHS standard deck of PAL specification (AG-6200 manufactured by Sony Corporation). Example 1 was set to 0 dB and shown as a relative value.
The higher the number, the better.

The measurement results are as shown in Table 2 below.

[0048]

From Table 2, it can be seen that according to the invention, the quality of the magnetic tape is significantly improved.

Next, a description will be given of an experiment in which the conductive adhesive roller used in Example 2 was used and the angle of inclination θ was changed to 度 °. The experiment conditions other than changing the angle of inclination θ are the same as those in the above experiment.

The experimental results are as shown in FIGS. From FIG. 5 and FIG. 6, it can be seen that good results can be obtained by setting the angle of inclination θ to 160 degrees or less.

In general, it is considered that the smaller the angle of inclination θ, the larger the area of contact of the base film with the conductive adhesive roller and the more the dust removal effect is obtained. However, the angle of inclination θ
When the angle is less than 90 degrees, the vibration at the time of separation of the base film and the adhesive roller becomes large, the amount of charge and the impression are increased, the dropout is increased, and the dust removing effect tends to be reduced. On the other hand, if it exceeds 160 degrees, the same tendency as that of less than 90 degrees was observed because the contact area width becomes narrow. Therefore, the angle of inclination θ is preferably set to an angle within the range of 90 to 160 degrees.

In FIG. 1, the static eliminator 18 is connected to the base film 1.
A is provided facing the surface on the application side of A, but may be provided facing the surface opposite to the application side since it is non-contact. Further, as shown by the imaginary line in FIG. 1, it may be provided immediately downstream of the conductive adhesive roller 13. However, by sufficiently lowering the electric resistance value of the conductive adhesive roller 13, the static eliminator immediately downstream thereof can be omitted.

Instead of the static eliminator shown by a virtual line in FIG. 1,
The conductive adhesive roller can have the structure shown in FIG.

The conductive adhesive roller 23 has a structure in which a core material 24 having a conductive adhesive layer 25 laminated on the peripheral surface is hollow, and a needle electrode 26 is disposed in a space inside the core material 24. To the needle electrode 26 and the base film 1A. In this way, a spark is generated between the needle electrode 26 and the base film 1A, dust adhering to the base film 1A is adhered to the conductive adhesive layer 25, and the base film 1A
To remove the static electricity generated.

In place of the carbon black 17 shown in FIG. 4, finely pulverized (particle diameter: about 0.1 μm) titanium oxide may be dispersed in the rubber 16.

The dust removal by the conductive adhesive roller is performed before the application of the magnetic paint and the back coat layer 33 shown in FIG.
Needless to say, it is similarly effective to perform before forming the undercoat layer 34.

Although the embodiments of the present invention have been described with reference to the manufacture of a magnetic tape for video as an example, the present invention is also applicable to the manufacture of various magnetic tapes for audio and the manufacture of floppy disks. It goes without saying that it can be played.

Further, the conductive adhesive roller according to the present invention comprises:
In addition to the manufacture of magnetic recording media, the present invention is effective in removing dust from electronic components such as printed boards, flexible printed circuits, capacitors, IC boards, etc., which do not like the attachment of dust.

[0060]

According to the present invention, a conductive adhesive roller having a plurality of conductive adhesive layers laminated on a core material alone is applied to the substrate side before the magnetic recording medium constituting layer is applied to the substrate. The contact angle is adjusted so that foreign substances such as dust adhering to the substrate can be effectively removed, and the static electricity generated by the above-mentioned contact is removed from the substrate by the conductivity of the roller. This prevents secondary adhesion of foreign matter due to the static electricity, and also prevents unstable running of the substrate due to the static electricity.

As a result, the obtained magnetic recording medium does not contain undesired foreign substances such as dust, does not cause dropouts or other inconveniences due to the foreign substances, and is of high quality and high reliability.

Further, the wear of the magnetic head due to the inclusion of foreign matter and the deterioration of the electromagnetic conversion characteristics due to the wear are prevented, and the recording / reproducing apparatus has a long life and high reliability.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a magnetic layer forming step of an example.

FIG. 2 is a perspective view showing the relationship between a conductive adhesive roller and a base film.

FIG. 3 is an enlarged front view of the conductive adhesive roller.

FIG. 4 is an enlarged partial cross-sectional view of the conductive adhesive roller.

FIG. 5 is a graph showing the relationship between the angle of inclination and the properties of the base film.

FIG. 6 is a graph showing the relationship between the angle of inclination and the properties of the magnetic tape.

FIG. 7 is an enlarged sectional view of a conductive adhesive roller according to another embodiment.

FIG. 8 is an enlarged sectional view showing the structure of a magnetic tape.

[Explanation of symbols]

1A Base film before application of magnetic paint 1B Base film applied with magnetic paint 2 Guide roller 3, 23 Backup roll 4 Magnetic paint 5 Gravure roll 11 Feeding roll 12 Winding roll 14, 24 Core material 15, 25 Conductive adhesive layer 16 Rubber 17 Carbon black particles 18 Static eliminator 26 Needle electrode 31 Base film 32 Magnetic layer 33 Back coat layer 34 Underlayer

Claims (5)

(57) [Claims] In producing a magnetic recording medium having a magnetic layer provided on a substrate, the method includes a step of applying a magnetic recording medium constituting layer, and before performing the coating, a plurality of conductive adhesive layers are attached to a core. A method for producing a magnetic recording medium, wherein a conductive adhesive roller laminated on a material is brought into contact with the substrate side at a predetermined angle by itself. 2. The magnetic recording medium according to claim 1, wherein an angle formed by each tangent between the entrance side contact point and the exit side contact point of the substrate with respect to the conductive adhesive roller is 90 to 160 degrees. Manufacturing method. 3. An apparatus for producing a magnetic recording medium in which a magnetic layer is provided on a substrate, comprising: substrate transport means;
Coating means for applying a coating material for forming a magnetic recording medium constituent layer on the base, and a conductive material comprising a plurality of conductive adhesive layers laminated on a core material, on the upstream side of the base means for transporting the coating. An apparatus for manufacturing a magnetic recording medium, wherein a non-stick adhesive roller is brought into contact with the substrate side at a predetermined angle by itself. 4. The apparatus for manufacturing a magnetic recording medium according to claim 3, wherein a static elimination means for neutralizing the substrate is provided only immediately before the coating means. 5. The apparatus for manufacturing a magnetic recording medium according to claim 4, wherein the conductive adhesive roller is disposed upstream of the static elimination means.