JPH07205033A - Magnetic tape polishing finish polishing wheel - Google Patents

Abstract

PURPOSE:To improve a surface so as to make it difficult for polishing dusts to be stuck thereto and to prevent sudden drop outs due to resticking of polishing dusts to the surface of a magnetic layer in a grinding wheel for giving polishing finish to the magnetic layer surface of a magnetic tape. CONSTITUTION:A grinding material layer 2 is formed of grinding particles 4 made of diamond powders and a bond material 5 made of bronze powders. A sticking prevention layer 3 is provided on the outer surface of the grinding material layer 2, thereby sticking of polishing dusts is prevented and incursion of polishing dusts into the air hole 6 and the recessed part of the grinding material layer 2 is prevented. The sticking prevention layer 3 is formed on a nonelectrolytic nickel plated layer by being coated by impregnation of fluorocarbon resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the manufacturing process of a magnetic tape, there is a step of polishing and finishing the surface of a magnetic layer with a polishing grindstone. The present invention relates to a polishing whetstone applied to the polishing and finishing of such a magnetic tape, and is to modify the surface of the whetstone to a physical property in which polishing dust is unlikely to adhere.

[0002]

2. Description of the Related Art FIG. 2 shows a principle diagram of a conventional apparatus used for polishing and finishing a magnetic tape. There, the polishing grindstone G is rotationally driven in a fixed direction, and the magnetic tape T wound around the peripheral surface thereof is fed in the direction opposite to the rotating direction of the polishing grindstone G to scrape off minute projections on the surface of the magnetic layer, or Foreign matter adhering to the surface is captured and removed. The polishing debris and foreign matter captured by the polishing grindstone G are collected and removed by the suction nozzle 11 arranged on the lower surface side to renew the surface state of the polishing grindstone G.
The suction nozzle 11 is connected to an intake source such as a vacuum pump or a blower. The grinding wheel G is a metal wheel body 1
On the circumferential surface, an abrasive material having high hardness abrasive particles such as diamond abrasive particles dispersed in a bond material such as bronze powder is sintered. Reference numeral 2 indicates the sintered abrasive material layer.

[0003]

In the above polishing finish mode, it is not possible to reliably collect and remove the polishing dust and the foreign matter captured by the polishing grindstone G. Moreover, the polishing scraps that could not be collected enter the gaps and pores between the abrasive grains and the bond material and accumulate,
When the amount of stagnant amount reached a certain value, the stagnant lumps fell off the surface of the grindstone, collapsed, and reattached to the magnetic layer. The reattached polishing dust or foreign matter induces a sudden dropout, which significantly impairs the recording characteristics of the magnetic tape. As a result of investigating the reason why polishing dust and foreign substances cannot be sufficiently removed by the suction nozzle, the present inventor has a strong affinity for the bonding material and the polishing dust, and therefore the polishing dust adheres to the surface of the grindstone and causes a suction air flow of the suction nozzle. I noticed that it was hard to come off even if exposed.

An object of the present invention is to provide a polishing grindstone for a magnetic tape, which can surely collect and remove polishing debris and foreign matters and prevent them from reattaching to the surface of the magnetic layer during polishing. . An object of the present invention is to provide a polishing grindstone suitable for polishing finishing of a magnetic tape, which does not cause reattachment of polishing dust or foreign matter, and therefore prevents occurrence of sudden dropout, and can exhibit good recording / reproducing characteristics. There is. An object of the present invention is to provide a polishing grindstone for a magnetic tape having a surface property that does not have an affinity for polishing dust and is unlikely to adhere to the polishing dust. Another object of the present invention is to provide a polishing grindstone for a magnetic tape, which can reliably prevent polishing debris from entering the abrasive layer.

[0005]

The polishing whetstone of the present invention is circumscribed on the surface of the magnetic layer 10 of the magnetic tape T fed in one direction, and the surface of the magnetic layer 10 is polished and finished while rotating in a predetermined direction. . The polishing grindstone includes a wheel body 1 made of metal and an abrasive layer 2 fixed to the peripheral surface of the wheel body 1. On the outer surface of the abrasive layer 2, there is an adhesion prevention layer 3 for preventing adhesion and retention of polishing dust. The anti-adhesion layer 3 is composed of a composite material of a metal having no affinity for polishing dust and a plastic material for preventing the adhesion of polishing dust. Specifically, the adhesion preventing layer 3 is formed by impregnating and coating a fluororesin on an electroless nickel plating layer. The abrasive layer 2 is formed by sintering and fixing a mixture of abrasive grains 4 made of diamond powder and a bond material 5 made of metal powder on the peripheral surface of the wheel body 1. Alternatively,
It is composed of abrasive grains 4 made of diamond powder, a bond material 5 made of metal powder, and chromium oxide 9 filling the pores 6.

The polishing whetstone of the present invention according to claim 5 circumscribes the surface of the magnetic layer 10 of the magnetic tape T fed in one direction, and polishes the surface of the magnetic layer 10 while revising in a predetermined direction. The grinding wheel is a metal wheel body 1,
The abrasive material layer 2 fixed to the peripheral surface of the wheel body 1 is included. The abrasive layer 2 is composed of abrasive grains 4 made of diamond powder, a bond material 5 made of metal powder, and chromium oxide 9 filling the pores 6. Then, a fluororesin is baked and fixed on the outer surface of the abrasive layer 2 to form an adhesion prevention layer 3 for preventing adhesion and retention of polishing dust.

[0007]

The function of the adhesion prevention layer 3 formed on the outer surface of the abrasive layer 2 is
The surface of the abrasive material layer 2 is covered and the pores 6 and the recesses exposed on the surface are closed to physically prevent polishing dust from entering the pores 6 and the recesses of the abrasive material layer 2. Forming the anti-adhesion layer 3 with a metal that has no affinity for polishing dust and a plastic material that prevents the attachment of polishing dust prevents the polishing dust from adhering to and staying on the surface of the adhesion preventing layer 3. This is to ensure removal of polishing dust and foreign matter by the suction nozzle 11 and obtain a good surface condition of the grindstone without adhesion of polishing dust and foreign matter. Due to the conductive action of the metal, the electrostatic attraction action due to the friction between the polishing grindstone and the magnetic tape T can be prevented.

In the anti-adhesion layer 3 formed by impregnating and coating the electroless nickel plating layer with the fluororesin, the nickel and the fluororesin are evenly dispersed, so that a smooth but hard and non-adhesive surface state is obtained. To be In the polishing grindstone according to the fourth aspect, since the pores 6 generated during the sintering of the abrasive layer 2 are filled with the chromium oxide 9, it is possible to reliably prevent polishing debris from entering the abrasive layer 2. Abrasive layer 2
In the polishing grindstone in which the anti-adhesion layer 3 formed by baking and fixing fluororesin on the outer surface is formed, the anti-adhesion layer 3 can physically prevent polishing debris from entering the abrasive layer 2, and the surface of the anti-adhesion layer 3 is polished. It is possible to prevent dust from adhering and staying. Further, the pores 6 of the abrasive layer 2 are filled with chromium oxide 9, and even if the adhesion preventing layer 3 is worn away, it is possible to reliably prevent the polishing dust from entering the abrasive layer 2.

[0009]

According to the polishing grindstone of the present invention, it is possible to prevent the polishing dust and the foreign matter from coming into direct contact with the abrasive layer 2 by the adhesion preventing layer 3, and further, the polishing dust and the foreign matter are formed on the surface of the adhesion preventing layer 3. Can be prevented from adhering and staying. This makes it possible to reliably separate and collect polishing debris and foreign matter that have been polished and removed from the surface of the magnetic layer 10 from the surface of the adhesion preventing layer 3 while the surface of the polishing grindstone G passes through the suction region of the suction nozzle 11. Magnetic layer 10
Will not redeposit on the surface. Therefore, the magnetic tape T
It is possible to obtain a magnetic tape that can always perform a proper polishing finish and that does not cause sudden dropout due to redeposition of polishing dust and the like and can always exhibit good recording / reproducing characteristics.

[0010]

【Example】

(Embodiment 1) FIG. 1 shows a polishing grindstone according to Embodiment 1 of the present invention. An abrasive material layer 2 is provided on the peripheral surface of a wheel body 1 made of a turned product such as steel or aluminum alloy. An anti-adhesion layer 3 is provided on the outer surface of the layer 2 to prevent the accumulation and retention of polishing debris.

The abrasive layer 2 is formed by mixing abrasive grains 4 made of diamond powder and a bond material 5 made of bronze powder. After sintering, pores 6 are formed between the abrasive grains 4 and the bond material 5, and between the bond material 5 and the bond material 5, respectively.
Are formed, and a recess is formed on the surface of the abrasive layer 2. The shape type of the wheel body 1 is AD-3-A (1AI), and when the diameter dimension is 100 mm, the thickness of the abrasive layer 2 is 0.5-0.5.
3.5 mm, specifically 2 mm, with composition such as D3000
N150M3.0.

The anti-adhesion layer 3 is composed of a composite material of a metal having no affinity for polishing dust and a plastic material for preventing the adhesion of polishing dust. More specifically, fluorocarbon resin is impregnated and coated while forming an electroless nickel plating layer on the outer surface of the abrasive layer 2. As this composite technology, for example, the technical product name “Technophos” manufactured by Asahi Techno Produce Co., Ltd. can be used. In the obtained anti-adhesion layer 3, nickel and fluororesin are uniformly dispersed, the hardness of the nickel film and the smoothness of fluororesin are simultaneously exhibited, and the adhesion resistance and peeling resistance are excellent. , It was possible to prevent electrostatic charge due to friction. The non-adhesiveness can be improved as compared with the case of performing electroless nickel plating or hard chrome plating.

(Embodiment 2) FIG. 3 shows an embodiment 2 of the present invention, in which an abrasive grain 4 made of diamond powder is used.
The bonding material 5 made of bronze powder and the chromium oxide 9 filling the pores 6 and the recesses (dotted portion in FIG. 3) constitute the abrasive material layer 2, and the others were the same as in Example 1. As the impregnation technique for the chromium oxide 9, the ceramic coating technique "K-ramic" by Usui Kokusai Sangyo Co., Ltd. was used.

There, a chromic acid aqueous solution is added to the mixture of the abrasive grains 4 and the bond material 5 to form a slurry, which is applied to the peripheral surface of the wheel body 1 and fired. Next, the surface of the fired abrasive material layer 2 is polished with an abrasive material to adjust its outer diameter dimension.
Further, the abrasive layer 2 is impregnated with a chromic acid solution and fired again. This impregnation and firing are repeated according to the densification grade. Finally, the peripheral surface was polished with an abrasive to adjust its surface roughness. Then, after completing the abrasive layer 2, Example 1
In the same manner as above, the adhesion prevention layer 3 was formed.

(Embodiment 3) FIG. 4 shows an embodiment 4 according to the present invention.
After the abrasive material layer 2 was formed in the same manner as in Example 2, the fluororesin was baked and fixed on the outer surface of the abrasive material layer 2 to form the adhesion prevention layer 3. Specifically, after the fluororesin is spray-coated on the outer surface of the abrasive layer 2, the abrasive layer 2 is coated with 135 to 25
By heating to 0 ° C. and maintaining this heating state for 10 minutes to 24 hours, the fluororesin layer was baked and cured.

In order to evaluate the degree of improvement of the above grinding wheel, a static evaluation test and an actual evaluation test were conducted. In the static evaluation test, the magnetic layer powder (including the binder) of the VTR magnetic tape having a particle size adjusted to 1 to 10 μm was attached to a swab, and the swab of 200 gf was cut on the surface of the sample piece cut out from the grinding wheel. The particles were rubbed 20 times in the reciprocating direction with pressure, and the magnetic layer powder scattered at the rubbed portions was scattered and removed by the jet air flow. 500 g / cm ^{2 of} adhesive tape with a rubber roller on the rubbing point of the above sample piece.
Then, the pressure-sensitive adhesive tape was pasted and the adhesive tape was immediately peeled off to obtain a sample for evaluation. The adhesive tape was repeatedly attached to the sample piece under the same conditions, and an evaluation sample was obtained until no adhered matter was observed on the adhesive tape. After obtaining the final evaluation sample, the state of residence of the magnetic layer powder on the surface of the sample piece was confirmed. In addition, as a polishing grindstone of a comparative example, a grindstone (# 3000) having an abrasive material layer composed of a ceramic bond material and fluorine-coated diamond abrasive grains.
It was used. The sample piece of the present invention was cut from the polishing grindstone of Example 1.

FIG. 5 shows the state of the evaluation sample obtained by the static evaluation test. In the comparative example, the magnetic layer powder adhered to the adhesive tape up to the eighth time. This means that the magnetic layer powder is difficult to separate from the sample piece. Further, it can be seen that the amount of magnetic layer powder adhered and dislocated to the adhesive tape is extremely large as compared with Example 1 of the present invention. On the other hand, it was confirmed that the magnetic layer powder had entered the pores and recesses of the sample piece even after the dislocation of adhesion to the adhesive tape was not observed. In the sample piece of the present invention, the adhesion of the magnetic layer powder to the adhesive tape was recognized only up to the third time, and the adhesion amount was also sparse. 3rd time or less,
No magnetic layer powder adhering to the surface of the sample piece was observed. Similar results were obtained with the rotating grindstones of Examples 2 and 3.

In the actual evaluation test, the VHS type magnetic tape T was ground and polished under the same conditions using the conventional grinding wheel and the grinding wheel of Example 2, respectively, and then provided with a multi-channel fixed head. The evaluator was used to confirm the presence or absence of sudden dropout of each magnetic tape. As the conventional grinding wheel, the same product as the comparative example of the static evaluation test was used.

As is apparent from FIG. 6 showing the test results, the average dropout of the magnetic tape polished by the conventional polishing grindstone was 15 pieces, which is normally at a good level, but sudden drop during the tape length of 3200 m. There are 7 to 8 outs, and the maximum level is 229. on the other hand,
In the magnetic tape polished by the polishing grindstone of the present invention, no sudden dropout was observed during the tape length of 5000 m, and the average dropout level was 7
The number was less than half that of the conventional example. Similar results were obtained with the magnetic tapes polished with the polishing grindstones of Examples 1 and 3.

Each magnetic tape used in the actual evaluation test was assembled into a tape cartridge of equal length, each tape cartridge was loaded into a VTR and recorded / reproduced under the same conditions, and the degree of occurrence of dropout was confirmed. The result is shown in FIG. 7. As is clear from the chart of FIG. 7, the average number of dropouts (-18 dB or more, 15 μS or more) generated per minute is 20 to 30 in the magnetic tape treated with the conventional grinding wheel. In each of Examples 1, 2 and 3, the number could be reduced to 5 to 10.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a polishing grindstone according to a first embodiment.

FIG. 2 is a diagram illustrating the principle of a magnetic tape polishing and finishing device.

FIG. 3 is a partial cross-sectional view of a polishing grindstone according to a second embodiment.

FIG. 4 is a partial cross-sectional view of a polishing grindstone according to a third embodiment.

FIG. 5 is a plan view of an evaluation sample group showing the results of a static evaluation test.

FIG. 6 is a chart showing the results of a production evaluation test.

FIG. 7 is a chart showing the results of another production evaluation test.

[Explanation of symbols]

 1 Wheel Main Body 2 Abrasive Layer 3 Adhesion Prevention Layer 4 Abrasive Grain 5 Bond Material 6 Porosity 9 Chromium Oxide 10 Magnetic Layer T Magnetic Tape

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 5/84 A 7303-5D

Claims (5)

[Claims] 1. A polishing grindstone that circumscribes the surface of a magnetic layer 10 of a magnetic tape T sent in one direction and polishes the surface of the magnetic layer 10 while rotating in a predetermined direction. Wheel body 1 and wheel body 1
And an abrasive material layer 2 fixed to the peripheral surface of the abrasive material layer, and an adhesion preventive layer 3 for preventing the adhesion and retention of abrasive particles is formed on the outer surface of the abrasive material layer 2. And a metal with no affinity,
A polishing whetstone for polishing and finishing magnetic tapes, which is made of a composite material with a plastic material that blocks the attachment of polishing dust. 2. The polishing whetstone for polishing and finishing a magnetic tape according to claim 1, wherein the adhesion preventing layer 3 is formed by impregnating and coating a fluororesin on an electroless nickel plating layer. 3. The abrasive layer 2 is formed by sintering and fixing a mixture of abrasive grains 4 made of diamond powder and a bond material 5 made of metal powder on the peripheral surface of the wheel body 1. A polishing whetstone for polishing finishing of the magnetic tape according to 1 or 2. 4. The magnetic material according to claim 1 or 2, wherein the abrasive layer 2 comprises abrasive grains 4 made of diamond powder, a bond material 5 made of metal powder, and chromium oxide 9 filling the pores 6. Abrasive whetstone for tape polishing. 5. A polishing grindstone that circumscribes the surface of the magnetic layer 10 of the magnetic tape T sent in one direction and polishes the surface of the magnetic layer 10 while rotating in a predetermined direction. The polishing grindstone is made of metal. Wheel body 1 and wheel body 1
The abrasive material layer 2 fixed to the peripheral surface of the abrasive material layer 2. The abrasive material layer 2 includes the abrasive grains 4 made of diamond powder, the bond material 5 made of metal powder, and the chromium oxide 9 filling the pores 6.
A polishing whetstone for polishing and finishing a magnetic tape, in which a fluorine resin is baked and fixed on the outer surface of the abrasive layer 2 to form an adhesion preventive layer 3 for preventing adhesion and retention of polishing debris.