JPH03110442A - Method and device for testing durability of flexible magnetic disk - Google Patents

Abstract

PURPOSE:To know the durability of the flexible disk with high accuracy from a measured value of the rotary torque of the spindle motor of a flexible magnetic disk device and its variation. CONSTITUTION:The driving torque of the spindle motor which drives the device where the flexible disk is loaded is found from the driving current value when the motor rotating speed is constant. At this time, the device equipped with the motor whose rotating speed becomes constant within a 2 - 150 g.cm rotary torque range of the spindle motor is used. When the durability of the FD is tested by using an actual FDD, not only information on a head gap part such as a reproduction output, but variation of a medium surface over the entire area of the contact surface between a head and the medium including a slide surface can be detected and the accurate durability can be evaluated. Therefore, the FD with high reliability is obtained. Further, abrasion powder of medium sticks on the head in the medium contact surface of the head including the slide surface to vary the rotary torque.

Description

DETAILED DESCRIPTION OF THE INVENTION A.Objective of the Invention [Industrial Application Field] The present invention is a method for testing the durability of a flexible magnetic disk, which tests the durability of a magnetic recording medium surface on which a magnetic head of a flexible magnetic disk slides. This article relates to test methods and test equipment.

[Conventional technology]

With the rapid spread of personal computers, the use of flexible magnetic disks (hereinafter referred to as FDs) as external storage devices has become widespread. One of the most important reliability requirements for this FD is running durability during repeated use.

Conventionally, the durability of this FD has usually been tested using an actual flexible magnetic disk drive (hereinafter referred to as FDD), and as a means of evaluation, a signal is recorded in advance on a specific track for one round, and then the FDD is driven. However, a commonly used method was to observe changes in the playback output of the same track.

However, the magnetic head (hereinafter referred to as the head) of an FDD consists of a head cavity that actually reads and writes magnetic recording signals, and a slider that is provided to support the head gap and ensure running stability. Because there are
The area where the head actually comes into contact with the FD medium surface spans several tracks.

Therefore, wear and scratches on the magnetic recording medium (hereinafter referred to as the medium) do not necessarily occur in the tracks above the head gap, and it may not be possible to accurately evaluate durability by observing the playback output. .

Furthermore, due to continuous running during a durability test, fluctuations in the playback output often occur due to off-track caused by minute deformation of the test medium or slight positional deviation of the head attached to the FDD. This has been a problem as it can sometimes make it difficult to make decisions.

[Problem to be solved by the invention]

The present invention has been made in view of the current situation. That is, the purpose of the present invention is to
A durability test method for providing reliable and accurate flexible magnetic disks by detecting changes not only in the head gap but also in the entire area where the head contacts the FD medium surface in the D durability test. and to provide testing equipment.

1. Structure of the Invention [Means for Solving the Problem] In order to achieve the above object, the present inventors investigated the factors that fluctuate FDD due to changes in the contact state between the medium and the head during continuous running. discovered that, when the rotational speed of the FDD spindle motor is constant, the rotational torque of the spindle motor when the head is in contact with the surface of the recording medium is closely related to changes in the surface condition of the medium, resulting in the present invention. It's arrived.

That is, on the medium contact surface of the head, including the slider surface, media abrasion particles generated due to abrasion or scratches on the medium surface adhere to the head, and this creates resistance in the medium running system.
It was found that the rotational torque of the spindle motor fluctuated as a result.

In the method of testing the durability of an FD using an actual FDD machine, the present invention measures the rotational torque of the spindle motor of the FDD from the above viewpoint, and uses the obtained values and changes thereof to determine the durability of the flexible magnetic disk. A durability test method for flexible magnetic disks, characterized by examining changes in durability, and a test device thereof, the test FD
A method for testing the durability of a flexible magnetic disk, characterized by having a spindle motor with a constant rotational speed in the range of 2g"C11 to 1505pc, and being able to measure the rotational torque of the spindle motor. This is the test equipment.

That is, the present invention provides the following features: 1. In a flexible magnetic disk durability test method for testing the durability of a flexible magnetic disk under the actual usage conditions of a flexible magnetic disk device, the rotational torque of a spindle motor of the flexible magnetic disk device is A durability test method for a flexible magnetic disk, characterized in that the durability of the flexible magnetic disk is determined from the value of a current flowing through a spindle motor while keeping the number of revolutions constant, and the durability of the flexible magnetic disk is determined from the obtained value and the value of its change.

2. Determine the driving torque of the spindle motor that drives the flexible magnetic disk device equipped with the flexible magnetic disk to be subjected to the durability test from the driving current value of the spindle motor when the rotational speed of the spindle motor is constant. In the durability test equipment, the rotational torque of the spindle motor was 2 g-c! This is a durability test for a flexible magnetic disk, which is characterized by using a flexible magnetic disk device equipped with a spindle motor that rotates at a constant speed in the range of 1 to 150 g-am.

[Effect]

According to the present invention, when testing the durability of an FD using an actual FDD machine, not only information on the head gap such as playback output but also information on the entire contact surface between the head and the medium including the slider surface is collected. Since surface changes can be detected and durability can be accurately evaluated, it is possible to provide highly reliable flexible magnetic disks.

Also, the rotational torque of the test FDD is usually about 50g-cm when the magnetic head contacts the FD surface, so when the FD surface is rough, the rotational torque of the FDD is 100g-cm.
The maximum weight was set at 150 g-cm. Also, when testing is carried out with the head lightly touching the FD surface, the minimum pressure is 2g'.
cm.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail using the drawings. FIG. 1 shows a schematic diagram of the FD durability testing apparatus of the present invention.

The FD durability test apparatus shown in FIG. Ru. At this time, the F
In order to measure fluctuations in the rotational torque of the DD spindle motor, the voltage across the resistive element 4 inserted between the FDD and the constant voltage power supply 2 is converted to X (measured value) (time) via the differential amplifier 3. Record on recorder 5. After converting the value recorded by the recorder into the rotational current of the spindle motor, the rotational torque is determined from the calibrated value of the torque-current characteristic.

The flexible magnetic disk durability test device according to this embodiment uses a method of detecting fluctuations in rotational torque by changes in the current value of the spindle motor. You may also install a motor torque detector and measure its output.

The FDD shown in FIG. 1 uses a commercially available 3.5" micro floppy disk drive, but normally the rotational torque when sliding on the medium surface during head compression is about 51 g-cm. The FDD may be an FDD having a spindle motor that rotates at a constant rotational torque within the range of 28'' CI to 150 g-cm.

Example 1 The composition of the magnetic layer differs depending on the flexible magnetic disk durability test apparatus configured as shown in FIG.

Continuous durability tests were conducted using two types of 3.5" 2HD micro floppy disks, A and B, as samples, and 10
Head N movement traces on the medium surface after 1,000,000 baths were observed.

At this time, a test FDD with a rotational speed of 30 rpm was used, and the number of test tracks was 12. The results are shown in FIG. 2 and Table 1.

Example 2 A durability test of a flexible magnetic disk was conducted in the same manner as in Example 1, except that a test FDD with a rotational speed of 600 rpm was used. The results are shown in FIG. 3 and Table 1.

Comparative Example 1 Test FDD with the same rotation speed as Example 1 at 300 rpm
A continuous durability test was conducted using a conventional method in which a 2F signal was previously recorded over one round on 12 test tracks, and then the change in the reproduction output of the same track was measured using a magnetic recording medium with different compositions. , and 3 of B.
A 5" 2HD microfloppy disk was used as a sample, and head sliding marks on the medium surface after 10 million baths were observed in the same manner as in Example 1. The results are shown in FIG. 4 and Table 1.

Comparative Example 2 An FD durability test was conducted in the same manner as Comparative Example 1, except that a test FDD with a rotational speed of 60 rpm was used. The results are shown in FIG. 5 and Table 1.

As is clear from Figures 2 and 3 and Table 1, 1000
For sample B, which had scratches when observed on the media surface after 10,000 baths, fluctuations in rotational torque and an upward trend were observed.
Regarding sample A, which had no change in surface condition, no variation in rotational torque was observed during the test.

In addition, when the head surface was observed after the test, in the test of Sample B where scratches occurred, media abrasion powder was observed to adhere to the head gap in Example 1 and to the slider edge in Example 2. On the surface, scratches were observed on tracks corresponding to the positions of these head deposits.

In contrast to these results, in Comparative Examples 1 and 2, as shown in Table 1, similar to Examples 1 and 2, scratches were observed on the media surface of Sample B after 10 million baths. However, as can be seen from FIGS. 4 and 5, the state of change in reproduction output was the same in all cases, and no major changes were observed.

In addition, when the head surface was observed after the test, it was found that Example 1
In the test of Sample B, which had scratches as in Example 2, media abrasion powder was observed on the slider edge in both Comparative Examples 1 and 2, and the positions of these head deposits were observed on the media surface. A scratch was observed on the corresponding track.

As is clear from the above results, by measuring the rotational torque of the FDD spindle motor during the FD durability test, it is possible to detect changes in the media surface over the entire head media contact surface, including the slider surface. Become.

Although the present invention has been described with respect to a 3.5" microfloppy disk, the effects of the present invention are not limited to only a 3.5" microfloppy disk;
It is natural that this effect is recognized in various types of flexible magnetic disks such as ``floppy disks'', 5.25'' mini floppy disks, 3'' compact floppy disks, 2# metal floppy disks, etc. It is not limited.

Margin Table 1 below C1 Effects of the Invention [Effects of the Invention] As described above, according to the present invention, when testing the durability of an FD using an actual FDD machine, the head gap can be measured by measuring playback output, etc. In addition to information, the method according to the present invention can detect changes in the medium surface over the entire head-medium contact surface, including the slider surface, making it possible to accurately evaluate durability. This makes it possible to provide a flexible magnetic disk with excellent properties.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a flexible magnetic disk durability testing apparatus according to the present invention. FIG. 2 shows different compositions of the medium according to Example 1 of the present invention.
A%B is a characteristic diagram showing changes in rotational torque with respect to the number of running passes when the rotational speed of the FDD of two flexible magnetic disks is 300 rpm. Figure 3 shows that the rotation speed of the FDD according to the second embodiment of the present invention is 60.
FIG. 3 is a characteristic diagram showing changes in rotational torque with respect to the number of travel passes when the rpm is 0. FIG. 4 is a characteristic diagram showing changes in reproduction output with respect to the number of running passes when the FDD rotation speed was 30 Orpm in the durability test according to Comparative Example 1. Fig. 5 is a characteristic diagram showing changes in reproduction output with respect to the number of running passes when the rotational speed of the FDD in the durability test according to Comparative Example 2 was 600 rpm.6 1...Flexible magnetic disk device (FDD), 2
...constant voltage power supply, 3...differential amplifier, 4...resistance element, 5...X-T recorder

Claims (1)

[Claims] 1. In a flexible magnetic disk durability test method for testing the durability of a flexible magnetic disk under actual use conditions of a flexible magnetic disk device, the rotational torque of a spindle motor of the flexible magnetic disk device is A method for testing the durability of a flexible magnetic disk, characterized in that the durability of the flexible magnetic disk is determined from the value of a current flowing through a spindle motor while keeping the rotational speed of the motor constant, and from the obtained value and the value of its change. 2. Determine the driving torque of the spindle motor that drives the flexible magnetic disk device equipped with the flexible magnetic disk to be subjected to the durability test from the driving current value of the spindle motor when the rotational speed of the spindle motor is constant. Durability of a flexible magnetic disk characterized by using a flexible magnetic disk device equipped with a spindle motor in which the rotational torque of the spindle motor reaches a constant number of rotations in the range of 2 g.cm to 150 g.cm in a durability testing device. Sex testing device.