JP3334367B2 - Magnetic tape roll evaluation apparatus and evaluation method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape raw roll evaluation apparatus for measuring the shape of a magnetic tape raw roll serving as a magnetic recording medium and judging whether or not the roll is defective, and an evaluation method using the same.

[0002]

2. Description of the Related Art In general, a magnetic tape as a magnetic recording medium is formed by cutting a magnetic tape raw roll called a jumbo roll into each tape width and producing a magnetic tape raw material called a so-called pancake. It is manufactured from the state. In other words, using the material roll, the peripheral surface of the material is equally divided and cut from one side edge to the other side for each tape width, and a tape winder is used from the equally divided material. Wind up the magnetic tape for each tape cassette.

[0003] Incidentally, the produced magnetic tape necessarily has a slight shape. This shape is such that the magnetic tape is bent rightward or leftward in the tape width direction as shown in FIG. If this shape is defined as a bending amount (maximum value) T to the right or left side of the magnetic tape with respect to the illustrated reference plane S, the bending amount T is approximately 1 as a product condition.
It needs to be 6 mm or less.

The above-mentioned shape is caused by the curvature of the peripheral surface of the magnetic tape raw material. Currently, as a method for determining the shape of the magnetic tape raw material, a roll-shaped raw material is cut into a tape width. Then, the degree of curvature is inspected for each web after each web has been set as a web.

[0005]

However, since the shape is determined after cutting for each tape width as described above, there is a great problem in terms of product yield. Because it is extremely difficult to ensure thoroughness every time, products with poor curvature become chronic,
There is a problem such as continuous defective products. Such a defective curvature is a main cause of a hitting waveform defect and a defective output of a product, and there is a possibility that the reliability of the product is significantly reduced.

[0006] Then, when the relationship between the amount of bending T and the hit waveform distortion was examined, as shown in FIG.
It can be seen that as the value increases, the hit waveform distortion increases substantially monotonically (its absolute value). Therefore, the present invention has been proposed in view of such a conventional situation, and the shape of a magnetic tape is extremely easily and reliably determined in the state of a roll-shaped raw material, and this shape is smaller than a specified value. It is an object of the present invention to provide a magnetic tape raw roll evaluation apparatus and an evaluation method using the same, which enable only a magnetic tape to be used as a product and can greatly improve the yield and reliability of the product.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to evaluate the shape of a magnetic tape raw roll, which is a magnetic recording medium, and to judge whether or not the magnetic tape is badly curved. This is an evaluation method using this. The evaluation device of the present invention is arranged to face the peripheral surface from one side edge to the other side edge of the raw magnetic tape roll, and scans from the one side edge to the other side edge to scan the peripheral surface. It has a measuring means for detecting the shape of the surface. That is, the evaluation device detects the peripheral surface shape in the state of the raw roll before cutting the raw roll into a tape width by the measuring device.

At this time, specifically, it is desirable to use a contact type shape sensor which detects the shape by sliding the measuring means on the output surface of the raw magnetic tape roll.
Further, in the present invention, when evaluating the peripheral shape of the roll-shaped raw material using the evaluation device, the measuring unit scans from one side edge to another side edge along the peripheral surface of the raw material. A first process of measuring the shape of the tape and calculating the shape change of the peripheral surface for each tape width (each channel) based on the result of the first process, and determining whether or not each satisfies a specified value. And a second step.

In this case, in the second step, the change in the shape of the peripheral surface of each tape width is represented by the difference Δt between the maximum value and the minimum value of the height within each tape width. Then, information on the peripheral surface shape measured by the measuring means is output as a voltage change from the measuring means, and the output signal is converted into an A / A signal.
After being converted into a digital signal by D conversion, the digital signal is taken into a computer, and various calculations are performed to obtain the roll shape of the raw material,
The difference Δt for each tape width, the average value of the difference Δt,
And a variance value σ are calculated to determine whether or not a specified value is satisfied for each tape width.

[0010]

In the magnetic tape roll evaluation apparatus of the present invention, the measuring means provided on the roll so as to cover from one side edge to the other side edge on the peripheral surface of the roll-shaped magnetic tape roll. Then, scanning is performed from one side edge to the other side along the peripheral surface of the raw material to detect the peripheral surface shape of the raw material. That is, since the magnetic tape is measured in the state of the material roll before being cut into the magnetic tape material (tape width material) for each tape width from the material roll, the peripheral surface of the material is easily and accurately measured. The shape is determined. Therefore, when each tape width raw material is cut, as a result of the above-described determination, a product that does not satisfy the specified value is removed and only a product that satisfies the specified value is used as a product. Inconveniences such as a decrease in output and distortion of the RF waveform due to a hit failure can be easily and reliably prevented.

In the present invention, the peripheral surface is equally divided for each tape width based on the peripheral surface shape of the raw roll measured in the first step, and the peripheral surface shape is determined for each tape width. The change is calculated and it is determined whether or not each satisfies a specified value. That is, since the judgment is automatically made for each tape width material in the material roll, when the material roll is cut from the material roll for each tape width to produce a material having a tape width, the specified value is surely set. It is possible to eliminate the unsatisfactory tape width material and to use only the material satisfying the specified value as a product.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, the shape of a magnetic tape as a magnetic recording medium is measured by using an evaluation device described later, and it is determined whether or not the tape is badly curved. Normally, a magnetic tape as a magnetic recording medium has a rotation axis L as shown in FIG.
It is manufactured from the state of the original roll 1 of a magnetic tape called a jumbo roll, which is installed rotatably around the center.
That is, using the material roll 1, the material roll 1
From the side edge portion 2a to the side edge portion 2b for each tape width and cut, and a tape winder is used from each of these equal width so-called pancake webs 3 having a tape width. And take up the magnetic tape for each tape cassette.

Incidentally, it is considered that the slight shape of the manufactured magnetic tape is caused by the curvature of the peripheral surface of the raw material tape 3, that is, the curvature of the peripheral surface 2 of the raw material roll 1. Therefore, the curvature (shape change) of the peripheral surface of each tape width is represented by a difference Δt between the maximum value and the minimum value of the height within each tape width,
The relationship between the amount of bending T shown in FIG. 8 and the difference Δt was examined.

As a result, as shown in FIG. 2, it can be seen that the bending amount T has a strong correlation with the difference Δt, and that they are substantially in a proportional relationship. Therefore, in order to know the bending amount T of the manufactured magnetic tape, the difference Δt may be measured. Therefore, as shown in FIG. 3, the magnetic tape material roll evaluation apparatus according to the present embodiment uses the peripheral surface 2 of the material roll 1.
Has a measuring means 11 installed on the material roll 1 so as to cover from the side edge 2a to the side edge 2b, and the measuring means 11 is provided along the peripheral surface 2 of the material 1 2a
To the other side edge 2b to measure the shape of the peripheral surface 2 of the material 1. That is, the evaluation apparatus measures the shape of the peripheral surface 2 in the state of the raw roll 1 before cutting the raw roll 1 into the respective tape width raw cloths 3 by the measuring apparatus 11.

At this time, when measuring the curvature of the peripheral surface 2 of the raw material roll 1 using the measuring means 11, the measurement is performed from the side edge 2 a to the side edge 2 b along the peripheral surface 2 of the raw material roll 1. The peripheral surface 2 is equally divided into n channels (n is a natural number) for each tape width, and the shape change of the peripheral surface 2 is measured for each channel to determine whether or not each satisfies a specified value. The measuring means 11 has a substantially rectangular shape, and a lower portion thereof is provided with a concave portion 14 excluding the end portions 12 and 13, and the concave portion 14 engages the raw roll 1 with the peripheral surface 2 at the time of measurement. Are combined. The concave portion 14 is provided with a contact-type shape sensor 21 as shown in FIG. The shape sensor 21 includes a main body 22 and a protruding sensor 23. One end of the sensor 23 is rotatably engaged with the main body 22. At the other end of the sensor section 23, a substantially spherical sensor 24 that is in direct contact with the peripheral surface 2 of the raw roll 1 during measurement is provided. Sensor unit 23
Is rotated and the sensor 24 scans from the side edge 2a to the side edge 2b along the peripheral surface 2 of the material roll 1 to measure the curvature of the peripheral surface 2 from channel 1 to channel n. I do.

As shown in FIG. 5, a relay board 31 for controlling the operation of the measuring means 11 is provided in the evaluation device.
A system control amplifier 32 into which an output signal of information on the shape of the peripheral surface 2 measured by the measuring means 11 is taken in;
A / D board 33 for A / D converting the output signal from
And a computer 34 for performing various calculations such as the difference Δt after the A / D conversion into a digital signal.
And a printer 35 for outputting calculation results.
Here, the pen recorder 26 is a device for recording only the shape of the peripheral surface 2 of the material roll 1 and outputting it to the system control amplifier 32.

FIG. 6 shows a flowchart for measuring the curvature of the peripheral surface 2 of the material roll 1 using the above-described evaluation apparatus, calculating the difference Δt, and making various determinations. That is, first, the measurement program is started and the type and lot No. of the raw roll 1 are determined. , Roll No. Is entered and confirmation is made. Thereafter, the measurement of the curvature of the peripheral surface 2 is started by controlling the measuring means 11 by the relay board 31.

Then, the output voltage from the measuring means 11 is read, taken into the system control amplifier 32, converted into a digital signal by the A / D board 33, and the measured value is displayed on the display 37, confirming the end of the measurement. Done. Thereafter, predetermined tape widths (channel widths) are calculated, and the difference Δt for each channel, a variation value of all channels (peak-to-peak, PP).
Value), the average value of the difference Δt, and the variance value σ are calculated.
Then, after storing and printing the measured data, it is determined whether or not the difference Δt for each channel satisfies a predetermined specified value, printed, and the entire process ends.

Based on the above determination result, when the raw material roll 1 is cut into tape width reductions 3 for each tape width, the tape width reductions 3 of the channels that do not satisfy the above-mentioned specified value are removed. Each tape cassette is manufactured using only the tape width reduction 3 satisfying the value. Here, an experimental example in which the raw roll 1 is actually determined using the above-described evaluation apparatus will be described. In this experiment, the peripheral surface 2 of the material roll 1 was divided into 47 channels for each tape width, and the measurement was made for determination. Shape (curved) of the peripheral surface 2
FIG. 7 shows the measurement results.

At this time, the average value of the difference Δt is 32.
1 μm, the overall PP value of the peripheral surface 2 was 532 μm, and the dispersion value was 23.6. Assuming that the specified value of the difference Δt, that is, the specification is 60 μm, the results for each channel are as shown in Table 1 below.

[0021]

[Table 1]

In Table 1, a circle indicates a judgment that satisfies a specified value, and a cross indicates a judgment that does not. In this experiment, channels 18, 19, 23, and 42 were evaluated as x (NG). Thus, in the evaluation device of the present embodiment, the side edge 2
a from the side edge 2a to the side edge 2b along the peripheral surface 2 of the web 1 by the measuring means 11 installed on the web 1 so as to cover from the a to the side edge 2b. The shape of the peripheral surface 2 of 1 is measured. That is, before the raw material roll 1 is cut into the magnetic tape raw material (tape width raw material) 3 for each tape width, it is measured in the state of the raw material roll 1, so that the raw material roll can be easily and accurately obtained. The shape of the peripheral surface 2 is determined. Therefore, when each tape width material 3 is cut,
As a result of the above determination, by removing those that do not satisfy the specified value and using only those that satisfy the specified value as products,
Inconveniences such as distortion of the RF waveform due to a bad contact of the magnetic head due to the shape of the magnetic tape can be easily and reliably prevented.

Further, in the present invention, when measuring the shape of the peripheral surface 2 of the raw material roll 1 using the above-described evaluation apparatus, the side edge 2a extends from the side edge 2a along the peripheral surface 2 of the raw material roll 1. The peripheral surface 2 is equally divided for each tape width up to 2b, the shape change of the peripheral surface 2 is measured for each tape width, and it is determined whether or not each satisfies a specified value. That is, since the determination is automatically made for each tape width material 3 in the material roll 1, when the roll shape material 1 is cut for each tape width to produce the tape width material 3, It is possible to reliably remove the tape width raw material 3 that does not satisfy the specified value and to use only the raw material 3 that meets the specified value as a product.

[0024]

As is clear from the above description, according to the present invention, the shape of a magnetic tape can be determined very easily and reliably, and only a magnetic tape whose shape is smaller than a specified value can be used as a product. , It is possible to greatly improve the yield and reliability of the product.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing an original roll.

FIG. 2 is a characteristic diagram showing a relationship between a difference Δt and a bending amount T of a magnetic tape.

FIG. 3 is a perspective view schematically illustrating a measuring unit that is a component of the evaluation device of the present embodiment.

FIG. 4 is a side view schematically showing a shape sensor which is a component of the measuring means.

FIG. 5 is a block diagram schematically showing the evaluation device.

FIG. 6 is a flowchart illustrating a state in which shape measurement and determination are performed using an evaluation device.

FIG. 7 is a characteristic diagram showing a difference Δt for each channel.

FIG. 8 is a schematic view showing a shape generated in a manufactured magnetic tape.

FIG. 9 is a characteristic diagram showing a relationship between a bending amount T of a magnetic tape and a hit waveform distortion.

[Description of Signs] 1 Material roll 2 Peripheral surface 2a, 2b Side edge 3 Tape width material 11 Measurement means 21 Shape sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-241127 (JP, A) JP-A-58-33155 (JP, A) JP-A-5-303742 (JP, A) JP-A 57-241 120193 (JP, A) JP-A-59-73717 (JP, A) JP-A-55-77117 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/84

Claims (4)

(57) [Claims] 1. A magnetic tape raw roll is disposed to face a peripheral surface from one side edge to another side edge, and scans from the one side edge to the other side edge to scan the peripheral surface. An apparatus for evaluating a raw roll of magnetic tape, comprising a measuring means for detecting a shape. 2. A magnetic tape raw roll evaluation apparatus according to claim 1, wherein the measuring means is a contact type shape sensor for detecting the shape by sliding the magnetic tape raw sheet into an output surface. . 3. A magnetic tape material roll evaluation apparatus according to claim 1, wherein said magnetic tape material roll evaluation device evaluates the peripheral shape of the roll material of the magnetic tape by measuring means on one side along the material peripheral surface. A first step of measuring the shape by scanning from the edge to the other side edge, and calculating a shape change of the peripheral surface for each tape width based on the result of the first step, and determining whether or not each of the specified values is satisfied. And a second step of determining whether or not the evaluation is performed. 4. The evaluation method according to claim 3, wherein in the second step, the change in the shape of the peripheral surface of each tape width is represented by a difference between the maximum value and the minimum value of the height within each tape width. .