JPH0973628A - Method for evaluating magnetic tape and evaluating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily and quantitatively evaluate the chipping resistance of a magnetic tape. SOLUTION: An operation button 34 is operated to revolve a revolving shaft 6 by a motor and a magnetic tape 32 is taken up and is made to travel by a reel 10. As a result, the surface on the base film side of this magnetic tape 32 slides relative to the lapping tape 28 at the point of a pin 14 and consequently, the surface of the base film is chipped and flaws are formed. At this time, the greater part of the powder formed by chipping of the surface of the base film is adhered to the sliding part of a lapping tape 28 to form a band region without splashing by electrostatic electricity. The number of the flaws generated in such a manner is observed by a microscope and the depth of the flaws is measured. Further, the width of the band region formed by adhesion of the powder on the lapping tape 28 is measured and is used as the index to indicate the amt. of the powder. The number of the flaws is large, the depth of the flaws is deep and the width of the band region is wide if the chipping resistance of the magnetic tape 32 is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for evaluating the abrasion resistance of magnetic tape.

[0002]

2. Description of the Related Art A magnetic tape such as a video tape cannot have sufficient performance as a magnetic recording medium unless its magnetic surface is uniform and smooth. In particular, if there are fine scratches on the magnetic surface, it becomes impossible to record a signal at that portion, and the corresponding signal is lost during reproduction, making it difficult to reproduce a complete image. Such a phenomenon is generally called dropout.

The fine scratches on the magnetic surface, which are the cause of the dropout, are often formed by powders produced by scraping a polymer compound film (for example, a polyester film) forming the base of the magnetic tape. That is,
Although various guide pins and guide rollers are used in a video tape recorder in order to run a magnetic tape on a predetermined path, when the magnetic tape travels through these guide members, the above-mentioned magnetic tape is formed. The base film is slightly scraped by the guide member, resulting in powder of the base film. Then, the generated powder scatters and adheres to the magnetic surface of the magnetic tape, and when the magnetic surface slides on the surface of the guide member or the magnetic head in that state, the magnetic surface is scratched by the adhered powder and scratched. Occurs.

Therefore, in order to prevent such scratches from occurring as much as possible, it is necessary to improve the base film so as to improve the abrasion resistance and suppress the generation of powder. In order to make such an improvement, the base film must first be evaluated, but conventionally, this evaluation was carried out by investigating how often the phenomenon of dropout occurs.

[0005]

However, in order to observe the dropout, for example, in the case of a video tape, it is necessary to complete the final product form, that is, a video cassette tape. That is, it is necessary to put a video cassette tape on a video tape recorder and perform recording / playback to check whether dropout occurs or how often it occurs.

Therefore, when a video cassette tape is manufactured, even if the base film has a problem related to dropout, it is discovered that it is not until the stage immediately before the manufacture and production of the video cassette tape. It is not possible. Further, even when the base film is improved and evaluated, the evaluation based on the observation of dropout is insufficient in terms of quantitativeness. Furthermore, there is a problem that a lot of time and labor are required for evaluation because it is necessary to record and reproduce by recording a video cassette recorder with hundreds of video cassette tapes such as several hundreds. Therefore, an object of the present invention is to provide a magnetic tape evaluation method and a magnetic tape evaluation apparatus that enable easy and quantitative evaluation of the abrasion resistance of a magnetic tape.

[0007]

In order to achieve the above-mentioned object, the present invention achieves the above object by a tape running step of running a magnetic tape at a predetermined speed, and pressing the surface of the wrapping tape against the surface of the running magnetic tape. Tape pressing step, a scratch counting step for counting the number of scratches formed on the surface of the magnetic tape, and an evaluation for evaluating the abrasion resistance of the magnetic tape by the number of scratches counted in the scratch counting step And a step. The present invention is also characterized in that, in the flaw counting step, the number of the flaws is counted by visually observing the surface of the magnetic tape with a microscope.

According to the present invention, after the tape pressing step, a flaw measuring step for measuring the depth of the flaw formed on the surface of the magnetic tape, and a depth of the flaw measured in the flaw measuring step are used. A second evaluation step of evaluating the abrasion resistance of the magnetic tape is further included. The present invention is also characterized in that, in the flaw measuring step, the depth of the flaw is measured by visually observing the surface of the magnetic tape with a microscope.

According to the present invention, after the tape pressing step, the amount of powder of the magnetic tape adhered to the surface of the wrapping tape produced by scraping the magnetic tape with the wrapping tape in the tape pressing step. And a third evaluation step of evaluating the abrasion resistance of the magnetic tape based on the amount of the powder of the magnetic tape measured in the powder quantity measurement step. Characterize. The present invention is also characterized in that, in the powder amount measuring step, the amount of the powder of the magnetic tape is measured by an area of a region where the powder of the magnetic tape adheres to the surface of the wrapping tape. And According to the present invention, in the powder amount measuring step, the powder of the magnetic tape is determined by the width of the region of the magnetic tape where the powder adheres to the surface of the wrapping tape in the running direction of the magnetic tape. It is characterized by measuring the amount of.

The present invention also suppresses the rotation of the first rotating shaft, the first reel around which the magnetic tape is wound and mounted on the first rotating shaft, and the first rotating shaft. A load means for applying a predetermined load to the first rotating shaft, a second rotating shaft, a second reel mounted on the second rotating shaft and winding the magnetic tape, and the second rotating shaft. A motor for rotating a rotating shaft, a pin on which a wrapping tape is applied, a first guide means for guiding the magnetic tape from the first reel to the pin on which the wrapping tape is applied, and the wrapping tape. And second guide means for guiding the magnetic tape from the pin to the second reel.

The present invention further includes a third reel around which the wrapping tape is wound, a fourth reel around which the wrapping tape is wound, and a supporting member for the third and fourth reels. It is characterized by The invention is also characterized in that the first and second guide means are pins or rollers.

In the magnetic tape evaluation method of the present invention, first, the magnetic tape is run at a predetermined speed in the tape running step, and in that state, the surface of the wrapping tape is pressed against the surface of the magnetic tape in the tape pressing step. , Sliding the surface of the magnetic tape against the surface of the wrapping tape. Then, in the scratch counting step, the number of scratches formed on the surface of the magnetic tape is counted, and in the evaluation step, the abrasion resistance of the magnetic tape is evaluated by the number of scratches counted in the scratch counting step. Further, in another magnetic tape evaluation method of the present invention, the scratch resistance of the magnetic tape is evaluated by measuring the depth of scratches formed on the surface of the magnetic tape, and the evaluation of yet another magnetic tape of the present invention. In the method, a magnetic tape is produced by shaving with a wrapping tape, and the amount of powder of the magnetic tape attached to the surface of the wrapping tape is measured to evaluate the abrasion resistance of the magnetic tape.

Further, in the magnetic tape evaluation apparatus of the present invention, the magnetic tape is wound from the first reel to the second reel and run by rotating the second rotating shaft by the motor. At this time, the magnetic tape is guided by the first guide means to the pin on which the wrapping tape is hung, and further from the pin to the second reel by the second guide means. Then, at the location of the pin, the surface of the magnetic tape slides on the surface of the wrapping tape, and the surface of the magnetic tape is scraped by the wrapping tape. Count the number of scratches that occurred as a result,
The abrasion resistance of magnetic tape can be evaluated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described. FIG. 1 is a plan view showing an example of a magnetic tape evaluation apparatus according to the present invention. On the top panel 12 of the magnetic tape evaluation device 2, two rotary shafts 4 and 6 are provided in parallel with each other at a predetermined interval. A reel 8 on the magnetic tape supply side is mounted on the rotary shaft 4, and a magnetic tape to be evaluated by the magnetic tape evaluation device 2 is wound around the reel 8. On the other hand, a reel 10 on the winding side is mounted on the rotary shaft 6.

A motor (not shown) is provided under the upper panel 12 near the rotary shaft 6, and the rotary shaft 6 is connected to the rotary shaft of the motor through a predetermined rotation transmission mechanism. On the other hand, with respect to the rotating shaft 4, a predetermined pad is pressed under the upper surface panel 12 via a spring, and an appropriate load for suppressing the rotation of the rotating shaft 4 is applied to the rotating shaft 4. These pads and springs constitute the load means according to the present invention.

A pin 14 is erected on the upper panel 12 at an intermediate position between the rotary shafts 4 and 6, and a guide pin 1 is provided at an oblique upper left position and an oblique upper right position close to the pin 14.
6 and 18 are erected. Two rotary shafts 2 are provided above the pin 14 and near the upper end of the top panel 12.
0 and 22 are erected at a relatively narrow predetermined interval. A reel 24 for supplying the wrapping tape is mounted on the rotary shaft 20, and a reel 26 for winding the wrapping tape is mounted on the rotary shaft 22. Wrapping tape 28 supplied from reel 24
Is hung on the pin 14 and wound on the reel 26.

Under the top panel 12, the rotary shafts 20 and 22 are pressed by springs with predetermined pads that prevent their rotation. These pads are on the top panel 12
When the lever 30 is in the left end position (state shown in the figure), the pad engages with the rotating shafts 20 and 22, and when the lever 30 is in the right end position, , The pad separates from the rotary shafts 20 and 22. Therefore, when the lever 30 is at the left end position, the reels 24, 2
6 is fixed and the wrapping tape 28 does not move.

The magnetic tape 32 to be evaluated wound on the reel 8 is the pin 14 on which the wrapping tape 28 is hung.
2 is guided by the guide pin 16, is hung on the guide pin 14 via the wrapping tape 28, and is guided by the guide pin 18 to the reel 10 on the winding side, as shown in FIG.

The operation button 34 is used to rotate and stop the motor for rotating the rotary shaft 6.
The running speed of the magnetic tape 32 when the motor is rotated is, for example, 500 m / min in the present embodiment. This value is a typical running speed for rewinding or fast-forwarding the video cassette recorder.

Further, as described above, the rotation of the rotating shaft 4 is suppressed by the pad, so that the magnetic tape 32 is used.
Is applied with a back tension, the strength of the present embodiment is, for example, 50 to 300 g for a 1/2 inch width magnetic tape.

The wrapping tape 28 is originally used for polishing, and is manufactured by 3M Company, Nippon Micro Company, FUJI.
They are manufactured by Tape Co., etc., and are commercially available, and they can be used. By the way, in this type of lapping tape, the polishing layer has silicon carbide and a metal oxide as main components and is formed by adding a binder, and the total thickness of the tape is about 25 μm to 100 μm. The roughness of the wrapping tape 28 used is, for example, the magnetic tape 32.
If the tape is for a video cassette tape, the surface roughness of the guide roller or guide pin incorporated in the video cassette is approximately the same.

Next, such a magnetic tape evaluation device 2
Along with the action of, the method of evaluating the magnetic tape according to the present invention will be described. The lever 30 is set to the left end position as shown in FIG. 1 so that the rotating shafts 20, 22 and hence the reels 24, 26 around which the wrapping tape 28 is wound do not rotate and the wrapping tape 28 does not move. In this state, as shown in FIG. 1, the reel 8 around which the magnetic tape 32 to be evaluated is wound is mounted on the rotating shaft 4, and the magnetic tape 32 is pulled out from the reel 8. Then, the wrapping tape 28 is hooked on the pin 14 through the guide pin 16 and further mounted on the winding side reel 10 through the guide pin 18.
Here, the length of the magnetic tape 32 wound around the reel 8 is, eg, 100 m or more. Also, the magnetic tape 32
It is assumed that the film is wound so that the surface on the base film side is outside.

Next, the operation button 34 is operated to rotate the rotary shaft 6 by the above motor, and the magnetic tape 32 is wound up by the reel 10 and run. As a result, the surface of the magnetic tape 32 on the side of the base film slides on the wrapping tape 28 at the position of the pin 14, and as a result, the surface of the base film is scraped and scratched. At this time, most of the powder generated by scraping the surface of the base film is attached to the sliding portion of the wrapping tape 28 without scattering due to static electricity.

Such running of the magnetic tape 32 is performed until the running distance reaches, for example, 150 m, and at that time, the operation button 34 is operated to stop the motor,
The running of the magnetic tape 32 is stopped.

Next, the magnetic tape 32 is removed from the apparatus together with the reels 8 and 10, and the surface of the base film of the magnetic tape 32 is observed with a microscope. By sliding on the wrapping tape 28 on the surface of the base film,
For example, a scratch 36 as shown in FIG. 3 is formed, the number of scratches is counted, and the depth of each scratch is measured.

It is necessary to measure the number of scratches and the depth of scratches at a fixed position on the magnetic tape. That is, by continuing the running of the magnetic tape 32,
As described above, the powder of the base film adheres to the location of the wrapping tape 28 on which the magnetic tape 32 slides, and the roughness of the location of the wrapping tape 28 also changes. Therefore, the number and depth of the scratches formed on the magnetic tape 32 also change, and therefore the magnetic tape 3
It is necessary to fix the counting and measuring positions such as observing a scratch at a position of 10 m from the tip of 2.
By doing so, it becomes possible to compare a plurality of magnetic tapes with each other.

Next, the wrapping tape 28 is attached to the reel 2
4, and 26 are removed from the apparatus, and the portion engaged with the pin 14 is observed with a microscope. At this point, the base film of the magnetic tape 32 is scraped by sliding of the magnetic tape 32, and the powder thereof is attached, and the attached powder forms a vertical strip 38 as shown in FIG. There is. This band 38 is observed with a microscope, and its width W is measured. This width W corresponds to the area of the band 38 because the width of the wrapping tape 28 is constant, and thus corresponds to the amount of powder scraped from the base film of the magnetic tape 32. That is, the width W becomes wider as the amount of scraped powder increases, and conversely, the width W becomes narrower as the amount thereof decreases.

When the base film of the magnetic tape 32 has high abrasion resistance, the number of scratches 36 formed on the film is small and the depth of the scratches 36 is shallow. And
Since the amount of powder generated by scraping the base film also decreases, the width W becomes narrow. On the contrary, when the base film of the magnetic tape 32 has a low abrasion resistance, the number of the scratches 36 formed on the film increases and the depth of the scratches 36 also increases. Then, the amount of powder generated by scraping the base film also increases, so that the width W becomes wide.

Therefore, the abrasion resistance of the magnetic tape 32 is quantitatively evaluated by the number and depth of the scratches 36 obtained as described above and the width W of the powder band 38 formed on the wrapping tape 28. Therefore, the abrasion resistance of the magnetic tapes can be compared with each other.

Further, such an evaluation can be performed without incorporating the magnetic tape 32 into a cassette as in the conventional case. Therefore, for example, when a video cassette tape is manufactured, the magnetic tape is relatively early in the manufacturing process. The abrasion resistance of can be evaluated. Since it is not necessary to record a signal on a magnetic tape and reproduce it to check for dropout as in the conventional case, the magnetic tape can be evaluated in a short time and without any trouble.

Needless to say, the magnetic tape evaluation method and the magnetic tape evaluation apparatus according to the present invention are not only video tapes to be incorporated in cassettes, but also open reel type video tapes, audio tapes, and computer. It can be used to evaluate the abrasion resistance of various magnetic tapes such as the magnetic tape used in the information storage device.

In the above-described embodiment, the abrasion resistance of the magnetic tape 32 is evaluated by the number and depth of the scratches formed on the magnetic tape 32 and the width W of the powder adhering to the lapping tape 28. However, in some cases, for example, the abrasion resistance can be evaluated only by the number of scratches formed on the magnetic tape 32, or only by the number and depth of the scratches.

The magnetic tape evaluation apparatus 2 described above
Has basically the same type of structure as, for example, an open reel type video tape recorder, and therefore, it is possible to improve the existing video tape recorder and the like.

Further, in this embodiment, the abrasion resistance of the base film of the magnetic tape 32 was evaluated. However, when a back layer is formed on the base film, the back layer is applied to the wrapping tape 28. Sliding, and therefore the abrasion resistance of the back layer can be evaluated. In addition, the magnetic tape 32 is turned inside out and the reel 8 is used.
It is also possible to evaluate the abrasion resistance of the magnetic layer by winding it on the magnetic surface side of the magnetic tape 32, that is, sliding the magnetic layer against the wrapping tape 28.

[0035]

As described above, in the magnetic tape evaluation method of the present invention, first, the magnetic tape is run at a predetermined speed in the tape running step, and in that state, on the surface of the magnetic tape in the tape pressing step, The surface of the wrapping tape is pressed to slide the surface of the magnetic tape against the surface of the wrapping tape. Then, in the scratch counting step, the number of scratches generated on the surface of the magnetic tape is counted,
Then, in the evaluation step, the abrasion resistance of the magnetic tape is evaluated by the number of scratches counted in the scratch counting step. Also,
In another magnetic tape evaluation method of the present invention, the scratch resistance formed on the surface of the magnetic tape is measured to evaluate the abrasion resistance of the magnetic tape. The abrasion resistance of the magnetic tape is evaluated by measuring the amount of powder of the magnetic tape attached to the surface of the wrapping tape, which is generated by shaving the magnetic tape with the wrapping tape.

Further, in the magnetic tape evaluation apparatus of the present invention, the magnetic tape is wound from the first reel to the second reel and run by rotating the second rotating shaft by the motor. At this time, the magnetic tape is guided by the first guide means to the pin on which the wrapping tape is hung, and further from the pin to the second reel by the second guide means. Then, at the location of the pin, the surface of the magnetic tape slides on the surface of the wrapping tape, and the surface of the magnetic tape is scraped by the wrapping tape. Count the number of scratches that occurred as a result,
The abrasion resistance of magnetic tape can be evaluated. Therefore, in the present invention, the abrasion resistance of the magnetic tape is quantitatively determined by the number of scratches formed on the magnetic tape, the depth of the scratches, and the amount of powder produced by scraping the magnetic tape. The abrasion resistance of magnetic tapes can be compared with each other. Moreover, such an evaluation can be performed without incorporating the magnetic tape into a cassette as in the conventional case, and therefore, the abrasion resistance of the magnetic tape is relatively early in the manufacturing process, for example, when manufacturing a video cassette tape. Sex can be evaluated. And
Since it is not necessary to record a signal on a magnetic tape and play it back to check for dropout as in the past, in a short time,
Moreover, the magnetic tape can be evaluated without much effort.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a magnetic tape evaluation apparatus according to the present invention.

FIG. 2 is an enlarged plan view showing in detail a part of the magnetic tape evaluation apparatus of FIG.

3 is a plan view showing a base film surface of a magnetic tape evaluated by the magnetic tape evaluation apparatus of FIG. 1. FIG.

FIG. 4 is a plan view showing a magnetic tape sliding portion of a wrapping tape which constitutes the magnetic tape evaluation apparatus of FIG.

[Explanation of symbols]

 2 Evaluation device 4, 6, 20, 22 Rotating shaft 8, 10, 24, 26 Reel 12 Top panel 14, 16, 18 Guide pin 28 Lapping tape 30 Lever 32 Magnetic tape 34 Operation button

Claims (10)

[Claims] 1. A tape running step of running a magnetic tape at a predetermined speed; a tape pressing step of pressing a surface of a wrapping tape against the surface of the running magnetic tape; and a step of forming on the surface of the magnetic tape. A scratch counting step of counting the number of scratches formed, and an evaluation step of evaluating the abrasion resistance of the magnetic tape based on the number of scratches counted in the scratch counting step, and an evaluation of the magnetic tape, comprising: Method. 2. The magnetic tape evaluation method according to claim 1, wherein in the scratch counting step, the number of scratches is counted by visually observing the surface of the magnetic tape with a microscope. 3. The magnetic tape according to the flaw measuring step of measuring the depth of the flaw formed on the surface of the magnetic tape after the tape pressing step, and the depth of the flaw measured in the flaw measuring step. The magnetic tape evaluation method according to claim 1, further comprising a second evaluation step of evaluating the abrasion resistance of the magnetic tape. 4. The magnetic tape evaluation method according to claim 3, wherein in the scratch measuring step, the depth of the scratch is measured by visually observing the surface of the magnetic tape with a microscope. 5. The amount of powder of the magnetic tape adhered to the surface of the wrapping tape is measured after the magnetic tape is scraped and produced by the wrapping tape in the tape pressing step after the tape pressing step. The powder amount measuring step, and a third evaluation step for evaluating the abrasion resistance of the magnetic tape based on the amount of the powder of the magnetic tape measured in the powder amount measuring step. 3. The magnetic tape evaluation method described in 3. 6. The amount of the powder of the magnetic tape is measured by the area of a region where the powder of the magnetic tape adheres to the surface of the wrapping tape in the powder amount measuring step. Evaluation method of the described magnetic tape. 7. In the powder amount measuring step, the powder of the magnetic tape is determined by the width in the running direction of the magnetic tape in the region where the powder of the magnetic tape adheres to the surface of the wrapping tape. 6. The method for evaluating a magnetic tape according to claim 5, wherein the amount of is measured. 8. A first rotating shaft, a first reel around which a magnetic tape is wound and mounted on the first rotating shaft, and the first reel for suppressing rotation of the first rotating shaft. A load means for applying a predetermined load to the first rotating shaft; a second rotating shaft; a second reel mounted on the second rotating shaft for winding the magnetic tape; and a second rotating shaft. A motor for rotating, a pin on which a wrapping tape is applied, a first guide means for guiding the magnetic tape from the first reel to the pin on which the wrapping tape is applied, and the pin on which the wrapping tape is applied. And a second guide means for guiding the magnetic tape to the second reel from the magnetic tape evaluation device. 9. A third part around which the wrapping tape is wound.
9. The magnetic tape evaluation apparatus according to claim 8, further comprising: a reel; a fourth reel that winds the wrapping tape; and support members for the third and fourth reels. 10. The magnetic tape evaluation apparatus according to claim 8, wherein the first and second guide means are pins or rollers.