JP2003123409A - Medium for measuring height of head carriage, its manufacturing method, and method for measuring height of head carriage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medium for easily measuring height dimensions of a head carriage, a method for manufacturing the medium, and a measuring method using the medium. SOLUTION: The manufacturing method uses a magnetic recording medium 2, a core bar 1 which is provided in the inner peripheral part of the magnetic recording medium and displaces the magnetic recording medium in the perpendicular direction in accordance with rotation, and a spindle motor 5 having a constitution for offsetting displacement caused by the core bar and records divided magnetization inverting groups 20 and 20a on the magnetic recording medium in accordance with the extent of displacement to manufacture the measuring medium, and height dimensions of the head carriage are easily measured by a reproduced output waveform from the magnetic recording medium of the measuring medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium for measuring the dimension in the height direction of a head carriage in a flexible disk device (also called FDD or floppy (registered trademark) disk device) used for an external storage device such as a personal computer. The present invention also relates to a method for manufacturing a head carriage height measuring medium and a head carriage height measuring method.

[0002]

2. Description of the Related Art Conventionally, the dimension measurement in the height direction of a head carriage of this type has been performed by measuring the mechanical dimension of the height of the head carriage with respect to the surface of the spindle motor, which serves as a reference, for receiving the core metal. .

[0003]

However, in the conventional dimension measurement of the head carriage in the height direction, a measuring means such as a pick tester for measuring the mechanical dimension relating to the height is inserted in the flexible disk device. It was necessary to remove the surrounding parts. For this reason, there is a problem that the dimension of the head carriage in the height direction cannot be measured in the state of the flexible disk device.
Furthermore, since a shim or the like is sandwiched between the spindle motor and the reference plane in the height direction of the head carriage and the output characteristics are measured by changing the height direction, the workability is very poor. The present invention solves such conventional problems,
An object of the present invention is to provide a measuring medium for easily measuring the dimension in the height direction of a head carriage in the state of a flexible disk device, a manufacturing method therefor, and a dimension measuring method in the height direction using the medium.

[0004]

In order to achieve the above-mentioned object, the present invention uses a measurement medium which is constructed so that the magnetic recording medium is displaced in the thickness direction along with rotation, and A plurality of divided magnetization reversal groups corresponding to the amount of displacement in the thickness direction are recorded on a magnetic recording medium on a predetermined track of the magnetic recording medium having a cored bar, and the magnetic recording medium is used as a spindle motor for measurement. The head carriage is reproduced, and the height of the head carriage is measured based on the amplitude of the reproduction output signal. With this configuration, the dimension in the height direction of the head carriage can be measured from the displacement corresponding to the height dimension of the magnetization reversal group divided so that the reproduction output signal amplitude decreases.

Further, according to the present invention, the amount of displacement of the core metal in the thickness direction of the magnetic recording medium is uniquely set with respect to the rotation direction. With this configuration, it is possible to measure the position where the reproduction output signal amplitude decreases by measuring the time or rotation angle, which increases the degree of freedom of the measurement system and also improves the workability because it is effective for automation. Can be made.

Further, according to the present invention, the reference of the rotating direction of the core metal is
This is based on the index pulse output once per rotation. With this configuration, the reproduction output signal amplitude can be measured in synchronization with the index pulse, which facilitates the measurement. Furthermore, since it is related to the case of recording a plurality of divided magnetization reversal groups on the magnetic recording medium, the management can be easily performed when used in a process or the like.

Further, according to the present invention, the wavelengths of the plurality of divided magnetization reversal groups are made shorter than the recording wavelength used for recording and reproduction. With this configuration, a large space loss can be obtained, so that the height dimension can be measured more easily.

Further, according to the present invention, a magnetic recording medium having a cored bar on the inner peripheral portion and displaced in the thickness direction with rotation, a spindle motor having an opposite displacement for canceling this displacement, and a head carriage are used to divide the magnetic recording medium. By the procedure of recording the plurality of magnetization reversal groups on the magnetic recording medium, the procedure of reproducing the magnetic recording medium by the spindle motor and the head carriage to be measured, and the procedure of measuring the amplitude of the reproduction output signal,
The height of the head carriage is measured. By this procedure, the height dimension of the head carriage can be measured from the displacement corresponding to the height dimension of the magnetization reversal group divided so that the reproduction output signal amplitude decreases, and the head carriage can be easily measured in the state of the flexible disk drive. It is possible to measure the dimension in the height direction. Further, it is possible to easily measure the dimensions even in the process.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a head carriage height measuring medium (hereinafter abbreviated as measuring medium) and a measuring method according to the present invention will be described below. FIG. 1 is a cross-sectional view of a main part for explaining writing to a measurement medium according to a preferred embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part for explaining measurement by a head carriage to be measured.
Is a perspective view of the measurement medium in the present invention, and FIG.
FIG. 5 is a cross-sectional view of a measuring medium according to the present invention, FIG. 5 is a cross-sectional view of an essential part including a partially enlarged view for explaining the relationship between the head and the medium in the height direction, and FIG. FIG. 7 is a diagram showing a state of a reproduction output waveform from the measurement medium in the preferred embodiment of the present invention, FIG. 8 is a plan view of a main part of the flexible disk device, and FIG. 9 is a diagram showing the present invention. It is a flow figure showing a procedure of creation of a medium for measurement, and height measurement of a head carriage. In each drawing showing the measurement medium, the exterior of the measurement medium is omitted.

In FIG. 1, a core metal 1 is arranged on an inner peripheral portion of a magnetic recording medium 2 and is rotationally driven by a spindle motor 5. The core metal 1 is made of magnetic stainless steel (such as SUS430). The magnetic recording medium 2 is fixed to the flange portion 1 a provided on the outer periphery of the core metal 1 by adhesion or the like. For characteristics of magnetic recording media, see JIS X 6223.
It is equivalent to the one specified in. The magnetic heads 3 and 4 arranged on the lower side and the upper side are respectively provided with soft magnetic material magnetic head cores 3a and 4a having R / W gaps (not shown) for recording or reproducing data. . On the upper surface of the spindle motor 5, a hub 6 on which the core metal 1 is mounted and a hub magnet 7 for magnetically attracting the core metal 1 are provided. The spindle shaft 8 and the drive pin 9 have positioning holes 30 provided in the core metal 1.
The magnetic recording medium 2 is positioned and rotated in cooperation with the drive hole 31.

FIG. 2 is a sectional view of an essential part for explaining the measurement of the head carriage to be measured. 1 that are the same as those in FIG. The magnetic heads 13 and 14 arranged on the lower side and the upper side are respectively provided with soft magnetic material magnetic head cores 13a and 14a having R / W gaps (not shown) for recording or reproducing data. . You may use the thing of the same characteristic as what is shown in FIG. On the upper surface of the spindle motor 15, the core metal 1
A hub 16 that does not change in the vertical direction (having a constant thickness) and a hub magnet 7 that magnetically attracts the core metal 1 are provided. When the measuring medium of the FDD to be measured is mounted, the measuring medium is
It rotates while changing its position in the height direction.

Next, the measuring medium in the present invention shown in FIGS. 3 and 4 will be described. In FIGS. 3 and 4, the core metal 1 is arranged on the inner peripheral portion of the magnetic recording medium 2 and is rotationally driven by the spindle motor 5. A center hole of the core metal 1 is provided with a positioning hole 30 having a substantially square shape and a driving hole 31 having a substantially rectangular shape at a position deviated from the center. The plurality of magnetization reversal groups 20 are concentrically divided with the positioning hole 30 at substantially equal intervals, and are divided by an unrecorded gap 21 having no magnetization reversal. The magnetization reversal group 20 is recorded in synchronization with an index pulse described later.
Further, among the magnetization reversal groups 20, the magnetization reversal groups 20a near the position where the index pulse is generated are the other magnetization reversal groups 2
It is made shorter than 0 to improve the discriminating property. The distance between the lower surface of the core metal 1 and the flange portion 1a is such that the side of the driving hole 31 is increased by L. (To be more precise, the length is increased by L at the distance corresponding to the hub 6.) In the present embodiment, the diameter of the contact portion where the core metal 1 and the hub 6 are mounted and the magnetic recording medium 2 Based on the diameter of the innermost track, the length L is about 0.2 mm. This value can be appropriately selected. Here, the magnetization reversal group 20 is provided on the innermost track because the rigidity of the magnetic recording medium 2 is inversely proportional to the fourth power of the radius of the track position, and thus becomes higher toward the inner peripheral side. The media keeps a stable contact with the head.

On the other hand, in the hub 6 provided in the spindle motor 5, the height direction is formed in a phase relationship opposite to that of the core metal 1. Therefore, as shown in FIG. 1, the magnetic recording medium 2 is adapted to rotate without displacement in the vertical direction. In the present embodiment, the distance between the lower surface of the cored bar 1 and the flange portion 1a is changed, but it is obvious that the same can be achieved by inclining the lower surface of the cored bar 1.

Next, the relationship between the reproduction output and the height of the head carriage with respect to the magnetic recording medium will be described with reference to FIGS. First, in FIG. 5, the flange portion 1 a of the core metal 1
When the distance in the height direction between the center line of the magnetic recording medium 2 in the thickness direction and the upper surface of the lower magnetic head 13 (hereinafter, also referred to as penetration Lp) is changed, the reproduction output signal from the magnetic head 13 is changed. The amplitude shows the characteristic as shown in FIG. In FIG. 6, the horizontal axis indicates the penetration Lp. Lp is 0 when the height of the upper surface of the lower magnetic head 13 and the height of the center line of the magnetic recording medium 2 in the thickness direction are the same, and the height of the upper surface of the lower magnetic head 13 is Lp. The direction higher than the center line in the thickness direction of is the positive sign. The vertical axis shows the normalized reproduction output signal amplitude. The solid and broken lines show the characteristics of the lower magnetic head 13 (referred to as side 0 S-0) and the upper magnetic head 14 (referred to as side 1 S-1), respectively. As the recording wavelength becomes shorter, the space loss also becomes larger and the absolute value of the slope in the characteristic of the output decrease as shown in FIG. 6 becomes larger. In FIG. 6, the innermost track 7
9 has a characteristic in which the magnetization is reversed at 300 kHz.

The reproduction output signal amplitude is stable in a certain range with respect to Lp, and decreases beyond this range. It is known that the characteristics are slightly different between the side 0 and the side 1, but this is different depending on the shape of the head, the support system, the head load, and the like. The decrease in output is mainly due to a loss (usually called spacing loss) due to a slight gap between the magnetic recording medium and the magnetic head.

FIG. 7 shows the waveform of the reproduction output waveform at S-0 from the measuring medium in one preferred embodiment of the present invention in almost one cycle. In the present embodiment, in the index pulse portion, the magnetization reversal group is shorter (that is, less) in the horizontal axis direction of FIG. 7 as compared with the other portions as described above, and the discriminating property is increased. .
Further, since the dimensional displacement amount in the height direction of the measuring medium is uniquely determined from the index pulse generation position, it is possible to perform time observation in synchronization with the index pulse. That is, it is possible to automatically measure the height of the head carriage by performing peak hold of the reproduction output and measuring the time from the index pulse.

In the present embodiment, the spindle motor rotates at a constant angular velocity (CAV) at 300 revolutions per minute (5 revolutions per second). Therefore, the index pulse generated for each rotation of the spindle motor 5 is
It is output every 200 ms cycle. In the present embodiment, the short magnetization reversal group 20a before and after the index pulse is 4.25 ms, and the other magnetization reversal groups 20 are 10.5 ms. An unrecorded gap 21 without magnetization reversal is set to about 2 ms. The wavelength of the magnetization reversal is the wavelength actually used in FDD (the track radius at the innermost circumference of S-1 is 23.18).
Approximately 1.46 μm at a recording frequency of 250 kHz at 75 mm
It becomes shorter than. Specifically, the recording frequency is 300 kHz (wavelength is about 1.21 μm). This is easier to measure because a larger space loss is obtained compared to the wavelength actually used in FDD. The space loss (Ls) is λ at the recording wavelength and Ls = −20Log between the gap d between the head and the recording medium.
The relationship of e ^{−2πd / λ} ≈ 54.6 * d / λdB is known. Since the recording wavelength is shorter, a larger space loss can be obtained, which facilitates the measurement.

In this embodiment, the magnetization reversal groups 20, 20 are
a is formed as a plurality of sectors along a predetermined annular track as shown in FIG. 3 (17 in the example shown).
sector). An unrecorded gap 21 having no magnetization reversal is provided between each sector. The magnetization reversal groups 20 and 20a as these sectors are provided corresponding to the penetration Lp with the position of the index pulse as a reference. That is, in the present embodiment, Lp is set to 0 at the position of the index pulse, and when the displacement in the height direction changes by 0.1 mm as the magnetic recording medium 2 rotates, the next sector Each sector is arranged along an annular track so that More specifically, the arrangement of the four sectors of the magnetization reversal group 20 following the index pulse causes the magnetic recording medium 2 to rotate with rotation.
Corresponding to the decrease of 0.1 mm, and the following four magnetization reversal groups 20 correspond to the increase of 0.1 mm so that the magnetic recording medium 2 returns to the original height. Lp is set to 0 in the sector of the inversion group 20.
Further, next, the magnetic recording medium 2 is similarly elevated from the sector of the eighth magnetization reversal group 20. In this way, with respect to Lp of 0, in the range of +0.4 mm to -0.4 mm,
The magnetic recording medium 2 is adapted to change in the height direction.
When the measuring medium is attached to the FDD to be measured, the measuring medium is located at the innermost circumference (track 7) with respect to the magnetic head.
In 9), the height direction rotates while changing in the range of +0.4 mm to -0.4 mm.

In the case where the reproduction output of a certain measured head carriage is as shown in FIG. 7, the reproduction output is the smallest in the fourth magnetization reversal group and is about 60% of the maximum output. Compared with the characteristics of FIG. 6, just Lp = −0.
It can be seen that this corresponds to outputs of 4 mm and 0.6 mm. This magnetic recording medium 2 has a height of +0.4 mm
Since it is made to change in the range of −0.4 mm, it can be seen that it corresponds to Lp = −0.4 mm. In other words, it can be understood that the height of this head carriage is a regular height. If the height of another head carriage to be measured is lower than the normal height, the reduction in reproduction output is further increased. For example, assuming that the height of the head carriage to be measured is about 0.2 mm lower than the normal height, the reproduction output in FIG. It can be understood that the maximum output is about 60%. On the contrary, the height of the measured head carriage is 0.2mm from the normal height.
When it is higher, the reproduction output is the smallest in the 12th magnetization reversal group, which is about 60% of the maximum output.

That is, it can be understood that the height of the head carriage can be easily measured based on the amount of change in the height direction of the measuring medium and the reproduction output waveform. The number of these magnetization reversal groups, the amount of change in height, and the like can be appropriately changed according to the system under measurement.

The side 0 has been described above, but it is clear that the side 1 can be measured in the same manner. In other words, it is obvious that both sides of the head can be measured with one sheet of measuring medium, and it goes without saying that the work efficiency is improved.

Now, FIG. 8 shows a plan view of a main part of the flexible disk device. In FIG. 8, the base plate 36 includes a spindle motor 15, a magnetic head carriage 39 having the magnetic head 14 mounted thereon, a guide rod 40 for guiding the magnetic head carriage 39 in the track direction, and a step motor 37 for moving the magnetic head carriage 39 in the track direction. The lead screw 38 and an electric circuit (not shown) are assembled. Further, a mechanism for attaching and detaching a recording medium such as a holder and an eject lever, which is not shown, is assembled above the drawing. Spindle motor 1 at a position having a fixed relationship with drive pin 9 (in this case, the side opposite to the magnetic head)
5 is provided with an index generator 35 for generating an index pulse for each rotation. Similar components are provided for writing to the measurement medium shown in FIG. As a result, the index pulse can be used as a reference for measurement. By using the time axis and the reproduction output that has been peak-held, it becomes possible to use it in the height direction of the magnetic head carriage in the FDD state in the process and as an index for process control. Even better, it is possible to easily perform measurement including a spindle motor and other mechanical dimensional variations.

Now, the procedure for producing the measuring medium and measuring the height of the head carriage in the present invention will be described with reference to FIG. First, a flow of creating the measurement medium will be described with reference to FIG. In advance, as shown in FIG. 1, a main part of an unrecorded medium having a cored bar whose height direction changes in its inner circumference is set in a writer (step S1). The spindle motor used for the writer is provided with a hub 6 having a shape such that the position in the height direction of the medium changes in antiphase with respect to the index generating portion (that is, to offset the displacement of the height position of the medium). It is provided and the core metal 1 is mounted on the hub 6. Next, the magnetization reversal group divided based on the index pulse obtained from the index generator is written to the unrecorded medium (step S2). The writing is confirmed (write verify) (step S3), the recording medium with the core metal 1 is taken out from the writer (step S4), the writing is completed, and the measurement medium is completed. in this case,
If write protection is performed to prevent writing, unnecessary erroneous writing in the process can be prevented, which improves usability.

Next, the flow of height measurement will be described with reference to FIG. Measuring medium is F for measurement
Set to DD (step S11). Next, the amplitude of the reproduction output signal is measured based on the index pulse (step S12). Next, the divided magnetization reversal group having the minimum reproduction output signal amplitude is measured based on the index pulse (step S13). Next, the amount of displacement in the height direction corresponding to the divided magnetization reversal group is obtained (step S14). The height dimension is calculated from the reference height dimension and the amount of displacement (step S1
5), the measurement is completed. With this flow, the head height can be measured in the FDD state in the process. Based on this data, it is possible to easily manage process capability and parts. Furthermore, other characteristic test items such as AM modulation (modulation) of the reproduced output signal amplitude can be substituted based on the measurement of the height dimension. According to the present embodiment,
When the measurement was carried out, it took about 1 hour per unit to measure the height of the head carriage in about 2 minutes per unit while still in the FDD state, which is a dramatic improvement. did it. According to this, in-line measurement is possible in the process. As can be understood from the above-described embodiments, the number of divided magnetization reversal groups and the displacement amount in the height direction can be appropriately changed.

[0025]

As is apparent from the above-described embodiment, the present invention is a magnetic recording medium having a cored bar on the inner peripheral portion which is displaced in the thickness direction of the magnetic recording medium with rotation, and a magnetic recording medium which is displaced in the thickness direction. A plurality of divided magnetization reversal groups corresponding to the quantity are recorded on the magnetic recording medium to manufacture a measurement medium, and the measurement medium thus manufactured is used to measure the magnetic recording medium. Reproduction is performed by the spindle motor and the head carriage, and the height of the head carriage is measured based on the amplitude of the reproduction output signal. With this configuration, the dimension in the height direction of the head carriage can be measured from the displacement corresponding to the height dimension of the divided magnetization reversal group in which the reproduction output signal amplitude decreases. Can be easily measured even in the state of the flexible disk device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part for explaining writing to a measurement medium according to a preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part for explaining measurement with a measured head carriage according to a preferred embodiment of the present invention.

FIG. 3 is a perspective view of a measuring medium according to a preferred embodiment of the present invention.

4 is a cross-sectional view of the measurement medium of FIG.

FIG. 5 is a cross-sectional view of an essential part including a partially enlarged view for explaining a relationship between a head and a medium in a height direction in a preferred embodiment of the present invention

FIG. 6 is a characteristic diagram showing the relationship between the height of the head and the medium and the reproduction output in the preferred embodiment of the present invention.

FIG. 7 is a diagram showing a state of a reproduction output waveform from the measurement medium according to the preferred embodiment of the present invention.

FIG. 8 is a plan view of a main part of a flexible disk device using a measuring medium according to a preferred embodiment of the present invention.

FIG. 9A is a flowchart showing a procedure for creating a measurement medium according to a preferred embodiment of the present invention, and FIG. 9B shows a procedure for measuring the height of a head carriage using the measurement medium according to a preferred embodiment of the present invention. Flow chart showing

[Explanation of symbols]

1 core 1a Flange part 2 magnetic recording media 3, 4, 13, 14 Magnetic head 3a, 4a, 13a, 14a Magnetic head core 5, 15 Spindle motor 6 hubs 7 Hub magnet 8 spindle shaft 9 drive pin 16 hubs 20, 20a Magnetization reversal group 21 Gap 30 Positioning hole 31 Drive hole 35 Index Generator 36 Base plate 37 step motor 38 Lead screw 39 Magnetic head carriage 40 Guide rod

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiji Takahashi             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             Matsushita Communication Industry Co., Ltd. F-term (reference) 5D068 AA01 BB03 CC03 EE05 EE13                       GG03                 5D091 AA09 FF01 FF05 FF07 GG33

Claims (8)

[Claims] 1. A magnetic recording medium, in which a plurality of magnetization reversal groups are recorded on a predetermined track, and a cored bar which is connected to an inner peripheral portion of the magnetic recording medium and is mounted on a hub of a spindle motor. However, the surface of the magnetic recording medium and the contact surface of the cored bar with the hub have an angle that forms an arbitrary inclination, and the reproduction output when the signal recorded by the plurality of magnetization reversal groups is reproduced. A head carriage height measurement medium for measuring the height dimension of the head carriage based on the amplitude. 2. The head carriage height measuring device according to claim 1, wherein a displacement amount in a thickness direction of the magnetic recording medium is uniquely set with respect to a reference position of the core metal. media. 3. The magnetization reversal group is configured such that, as a reference position of the core metal, an index pulse synchronized with a physical position of the reference position is output once per rotation. Item 3. The head carriage height measurement medium according to Item 1 or 2. 4. The head carriage height measuring medium according to claim 1, wherein a wavelength of the magnetization reversal group is shorter than a recording wavelength used for recording and reproduction. 5. When recording the plurality of magnetization reversal groups on the recording medium, the upper and lower surfaces of the hub cancel the angle between the contact surface of the cored bar mounted on the hub and the magnetic recording medium. 5. The head carriage according to claim 1, wherein the plurality of magnetization reversal groups are recorded at an angle, and thus when the recording medium rotates, the position in the thickness direction is constant. Height measuring media. 6. A core metal mounted on a hub of a spindle motor on an inner peripheral portion of a substantially annular magnetic recording medium, and a portion of the core metal mounted on the hub and the magnetic recording medium have a predetermined inclination angle. A step of connecting the core magnetic head to a hub having an inclination angle such that the inclination angle is offset; a step of rotating the magnetic recording medium by the spindle motor; And a step of supplying a signal to record a plurality of magnetization reversal groups on a predetermined track, the method for manufacturing a head carriage height measuring medium. 7. A magnetic recording medium in which a plurality of magnetization reversal groups are recorded on a predetermined track, and a cored bar which is connected to an inner peripheral portion of the magnetic recording medium and is mounted on a hub of a spindle motor. Head for height measurement of a head carriage, wherein the magnetic recording medium is attached to the core metal such that its position in the thickness direction changes with rotation when the hub has no inclination. A method for measuring the height of a head carriage of a magnetic recording / reproducing apparatus to be measured by applying a medium for measuring the height of a carriage to a magnetic recording / reproducing apparatus to be measured, comprising: Placing gold on a hub of a spindle motor of the magnetic recording and reproducing apparatus to be measured; rotating the magnetic recording medium by the spindle motor; A head carriage height measuring method, comprising: a step of reading a signal from the plurality of magnetization reversal groups with a battery; and a step of measuring an amplitude of the read signal. 8. The head carriage height measuring method according to claim 7, further comprising the step of determining whether or not the height of the head carriage conforms to a standard from the magnitude of the measured amplitude.