JPH05266471A - Surface treating device for producing magnetic recording medium - Google Patents

Abstract

PURPOSE:To satisfactorily remove unfavorable foreign matter on the surface of a magnetic layer by effective lapping and to obtain a magnetic tape nearly free from defects such as dropout and having high reliability. CONSTITUTION:A lapping device used has a lapping tape 2 for lapping the surface of the magnetic layer 1a of a magnetic tape 1 and a backup roll 3 for bringing the lapping tape 2 into sliding contact with the surface of the magnetic layer 1a while in contact with the tape 2. A circular body 11 with a large number of linear surface protrusions and grooves has been fixed on the peripheral surface of the backup roll 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus for manufacturing a magnetic recording medium.

[0002]

2. Description of the Related Art In the manufacturing process of a magnetic recording medium such as a magnetic tape, dust adheres to the surface of the magnetic layer, or minute projections on the surface of the magnetic layer which cannot be smoothed by calendering (for example, agglomerates in magnetic paint). Microscopic projections, etc.) may remain, and these foreign matters such as dust and microscopic projections may cause dropouts, leading to a reduction in S / N ratio.

In order to remove the above deposits and minute protrusions,
A wiping method using a blade or cleaning paper and a wiping method in which a lapping tape called a vanisher is brought into sliding contact with the magnetic layer are generally adopted.

In the wiping operation using this wrapping tape, the magnetic tape material after calendering is run along the peripheral surface of a cylindrical roller having a smooth surface, and the winding roll is wound on the surface of the magnetic layer of this magnetic tape material. A surface treatment device is used which is configured to press-contact a wrapping tape traveling over a winding roll.

In the wiping method using the blade or the cleaning paper, the above-mentioned deposits and minute projections are not sufficiently removed.

Further, in the wiping method using the wrapping tape, when the sliding contact speed between the wrapping tape and the magnetic tape material becomes high, air is entrained in the sliding contact surface between the two and the air film layer is thereby formed. There is a problem that the wiping effect is reduced due to the intervention.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a surface treatment for producing a magnetic recording medium, in which deposits and minute projections on the surface of the magnetic layer of the magnetic recording medium material are effectively removed. The purpose is to provide a device.

[0008]

That is, the present invention relates to a lapping member for lapping the magnetic layer surface of a magnetic recording medium material, and a sliding contact means for slidingly contacting the lapping member with the magnetic layer surface while contacting the lapping member. And a surface treatment apparatus for manufacturing a magnetic recording medium in which unevenness is formed on a contact surface of the sliding contact means with the lapping member.

The "concavo-convex" means, for example, the widths w ₁ and w _{2 of the} rubber annular body 11 shown in FIG. 4 described later are 0.1 mm to 150 m.
It refers to unevenness with a depth of 0.1 mm or more at m. However, width w ₁ ,
It is preferable to set w ₂ to an appropriate size depending on the diameter of the annular body 11, and when the diameter is 60 mm or less, it is preferably 0.1 to 1.8 mm. Further, the convex and concave portions may be semicircular, and in this case, the radius is 0.05 to 75 mm. The diameter of the annular body 11 is 60 mm
In the following cases, the radius is preferably 0.05 to 1.8 mm.

[0010]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a perspective view showing a main part of a magnetic tape material lapping device, and FIG. 2 is a partial front view of FIG.

The magnetic tape material 1 has one end wound around a payout hub 5 and the other end wound around a takeup hub 6, and is guided by guide rollers 4 and 4 as the takeup hub 6 rotates. Run like.

The wrapping tape 2 has one end side wound around the payout hub 8 and the other end side wound around the takeup hub 9, and the rotation of the takeup hub 9 causes the guide rollers 7, 7 to move between the guide rollers 7, 7. The vehicle is guided by the backup roller 3 located above and travels as indicated by arrow B.

The upper end position of the backup roller 3 is higher than the lower end positions of the guide rollers 4 and 4, and the magnetic tape material 1 is lapped with a contact pressure P by the positional relationship between these and the tension of the magnetic tape material 1. The tape 2 is slidably contacted. That is, the backup roller 3
Functions as a backup roller for the wrapping tape 2.

The above sliding contact is caused by the surface of the magnetic layer 1a of the magnetic tape material 1 and the abrasive grain surface (Cr) of the wrapping tape 2.
₂ O ₃ , SiC, Al ₂ O ₃ or the like coated surface 2 a are in sliding contact with each other.

Even if the sliding contact speed between the magnetic tape material 1 and the wrapping tape 2 becomes high, in order to prevent air from being entrapped in the contact surface between the two, the magnetic tape is made magnetic to the extent that an air film is not formed. It is necessary to increase the contact pressure P of the tape material 1 to the wrapping tape 2.

In order to increase the contact pressure P, the tension of the magnetic tape material 1 is increased, and the diameter of the backup roller 3 is decreased to reduce the contact area between the magnetic tape material 1 and the wrapping tape 2. There are two possibilities.

In the former method, the magnetic tape material 1 may be permanently deformed. Therefore, the latter method is preferable.

However, it is well known that the lapping amount is influenced by both the contact pressure and the contact length, and the contact length becomes small and the lapping is sufficient by simply reducing the diameter of the backup roller 3. Will not be done.

Therefore, it becomes necessary to arrange a large number of small-diameter backup rollers to increase the total contact length. However,
In this case, it is inconvenient to design the contact pressure to be equal at the position of each backup roller, and the device becomes complicated and large.

What should be noted in this example is that a large-diameter backup roller is provided with irregularities on its outer peripheral surface so that each of a large number of convex portions formed thereby functions similarly to a small-diameter backup roller. That is.

That is, as shown in FIGS. 1 and 2, the outermost peripheral layer of the backup roller 3 is uneven (11a) parallel to the central axis.
Is a hard rubber annular body 11 provided with a convex line and a concave line 11b. As a result, in the contact area between the magnetic tape material 1 and the wrapping tape 2, the pressure contact between the magnetic tape material 1 and the wrapping tape 2 is made by the five ridges 11a, and a contact pressure similar to that when five backup rollers of small diameter are arranged can be obtained.

The backup roller 3 is III-II in FIG.
As shown in FIG. 3 which is an enlarged sectional view taken along the line I, the annular body 11 is externally fitted and fixed to the peripheral surface of the cylindrical iron base body 12, and the base body 12 is a bearing.
It is supported by a fixed shaft 14 via 13. As the wrapping tape 2 travels, the backup roller 3 rotates following this. The annular body 11 is made of an elastic body such as silicone rubber, and is formed by a method of forming by drawing, a method of adhering a sheet-shaped material, or a cutting process.

In this example, as shown in FIG. 4 which is an enlarged sectional view taken along line IV-IV of FIG.
The width w ₁ of the upper end of a is ₁ mm, the width w ₂ of the bottom of the groove 11b is 1.8 mm,
The depth d of the unevenness is 1.5 mm. The outer diameter of the backup roller 3 including the ridge 11a is 6 mm (Example 1) or 30 mm.
This is (Example 2).

By constructing the backup roller 3 as described above, even if the contact pressure P becomes sufficiently large and the sliding contact speed between the magnetic tape material and the wrapping tape becomes high, this is almost the same as in the case of low speed. A degree of wrapping effect can be achieved.

Next, an experiment in which the magnetic tape material is lapped and the number of dropout occurrences per unit time is measured will be described.

Magnetic tape material: VHS tape (regular grade), 1/2 inch width; Lapping tape: SiC abrasive grains with a grain size of 5 μm applied to a polyester film together with a binder and dried; magnetic tape material and lapping film Sliding speed of: 3
00 m / min, 500 m / min, 700 m / min; Lapping conditions are as shown in Table 1 below.

[0028]

Under the above conditions, -20 dB or more and 15 μsec
We measured the number of times that output down (dropout) more than 10 hours occurred in 10 minutes. In this experiment, the number of occurrences of dropout was measured over 15 minutes.

The experimental results are shown in FIGS. 5 and 6 and Table 2 below. 5 and 6 also show the results of measurement for output down of -16 dB or more and 3 μsec or more. For comparison, a backup roller having a smooth surface (diameter 30 mm) was used and the lap angle was 180 degrees (comparative example). The results are shown in FIG. 10, and the results are also shown in Table 2. ..

[0031]

The apparatus of the comparative example comprises the guide roller 4 shown in FIG.
4 is positioned directly above the guide rollers 7, 7, both guide rollers have the same diameter, and the wrap angle θ is 180 degrees.

The following can be understood from FIGS. 5, 6, 10 and Table 2.

In the comparative example, the lapping effect decreases as the sliding contact speed increases (dropouts increase). On the other hand, in Example 1, substantially the same lapping effect is recognized regardless of the sliding contact speed.

In the second embodiment, when the sliding contact speed is as high as 700 m / min, the lapping effect is slightly reduced.
It is considered that this is because the wrapping tape was slightly clogged from the observation of the wrapping tape after lapping described below. Therefore, it is considered that the backup roller 3 should not be made too small in diameter.

In the comparative example, it was observed that the contamination of the wrapping tape after lapping was reduced in the central portion in the width direction as the sliding contact speed was increased. this is,
It is considered that the air film was formed in the central portion in the width direction and was not discharged to the outside.

On the other hand, in the lapping tapes after the lapping of Examples 1 and 2, substantially uniform band-like stains were observed in the width direction, and it was recognized that the air film was not formed. It is considered to be remarkable.

The magnetic tape material that has been lapped as described above is wound on another predetermined hub and cut into a predetermined length to form a completed magnetic tape.

FIG. 7A shows the annular body 11 of the backup roller.
It is an expansion development view of the surface. The annular body 11 is provided with a large number of convex strips 11a and concave strips 11b formed in the width direction alternately and in parallel with each other. In addition, for example, FIGS. 7 (b) to 7 (d)
As shown in a similar developed view, the convex portion and the concave portion of the annular body may have other appropriate shapes.

In the annular body 21A of FIG. 7 (b), the concave stripes 23A are formed in a grid pattern, and the rectangular convex portions 22A are provided between them.

In the annular body 21B shown in FIG. 7 (c), a rectangular convex portion
22B are provided in a zigzag manner, and recesses 23B are formed between them.

In the annular body 21C of FIG. 7 (d), a rectangular recess
Providing a large number of 23C in a zigzag pattern and surrounding them
It forms 22C.

Further, as shown in FIG. 8, the width of the groove 11b in FIG. 2 is set to zero, and the groove 11a in FIG.
You may use the annular body 31 made into 31a.

Further, instead of the backup roller 3 shown in FIG. 2, a pulley 33 having a smooth surface can be used as shown in FIG. Then, an endless belt 35 having a large number of convex strips 35a and concave strips 35b alternately provided in the width direction is hung on the pulley 33 and the pulley 34, and the wrapping tape 2 and the magnetic tape material 1 are attached to the belt 35 in this order. Make contact. In this example, the belt 35 is formed by running the wrapping tape 2.
Is driven and goes around, and the pulleys 33 and 34 rotate.

Although the embodiments of the present invention have been described above, various modifications can be made to the above embodiments based on the technical idea of the present invention.

For example, the present invention can be similarly applied to manufacture of VHS magnetic tapes, as well as manufacture of other magnetic recording media such as magnetic tapes and floppy disks having different width dimensions.

Further, the surface treatment apparatus according to the present invention can be applied to a wide range from a wide roll to a pancake cut into a predetermined width after applying the magnetic paint in the magnetic tape manufacturing process.

[0048]

According to the present invention, since the sliding contact surface of the sliding contact means for slidingly contacting the lapping member with the magnetic layer of the magnetic recording medium material is formed with unevenness, the lapping member and the magnetic recording medium material are Sliding contact is performed with sufficient contact pressure and sufficient total contact length.

As a result, a reliable lapping effect that undesired dust and foreign matter such as minute projections existing on the surface of the magnetic layer is sufficiently removed is produced, and the magnetic recording medium to be manufactured has a dropout or the like. It will be defect-free and highly reliable.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts of a magnetic tape material wrapping device according to an embodiment.

FIG. 2 is a partial front view of FIG.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged partial sectional view taken along line IV-IV of FIG.

5 is a graph showing experimental results of Example 1. FIG.

FIG. 6 is a graph showing the experimental results of Example 2.

FIG. 7 is an enlarged development view of the surfaces of a plurality of types of backup roller annular bodies according to the embodiment.

FIG. 8 is a front view of essential parts of a magnetic tape material wrapping device according to another embodiment.

FIG. 9 is a front view of a main part of a magnetic tape material lapping device according to still another embodiment.

FIG. 10 is a graph showing an experimental result of a comparative example.

[Explanation of symbols]

 1 magnetic tape material 1a magnetic layer 2 lapping tape 2a abrasive grain surface 3 backup roller 4, 7 guide roller 11, 31 annular body 11a, 31a annular convex ridge 11b annular concave 33, 34 pulley 35 belt 35a belt Convex line 35b Concave line of belt

Claims (1)

[Claims] 1. A lapping member for lapping the surface of a magnetic layer of a magnetic recording medium material, and a sliding contact means for slidingly contacting the lapping member with the surface of the magnetic layer while contacting the lapping member. A surface treatment apparatus for manufacturing a magnetic recording medium, wherein unevenness is formed on a contact surface of the sliding contact means with the lapping member.