JP2001266519A - Servo track writer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakages owing to the lowering of the pressure of pressurized air supplied to an air bearing part of a spindle in writing of a servo signal. SOLUTION: A flexible disk 21 is held by the spindle 31 of a rotating means 3 and rotated at a prescribed rotational speed to write in the servo signal. A control means 100 is provided to stop the driving of the rotating means 3 when the supply pressure lowers below the prescribed value by the detection of a pressure detection means 81 provided in an air passage 8 for supplying pressurized air to the air bearing part of the spindle 31. It is desirable to secure the supply of the air until the means 3 actually stops by interposing an air tank 83 for backup in the air passage 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a servo track writer for writing a servo signal for accurately positioning a magnetic head of a disk drive on a flexible disk.

[0002]

2. Description of the Related Art Conventionally, a magnetic layer is formed on both sides of a disk-shaped base made of a flexible polyester sheet or the like, and a flexible disk on which signals can be magnetically recorded using a magnetic head is used as a magnetic disk medium. It is offered as a kind.

[0003] This flexible disk is usually provided as a disk cartridge in which a hard hub (center core) is mounted at the center of a disk and the whole is housed in a plastic cartridge case. It is mainly used as a recording medium for a computer because of its advantages such as low cost. Among such disk cartridges, in a high-density disk cartridge, it is necessary to position the magnetic head by closed loop control. For this control, it is necessary to prerecord servo signals concentrically on a flexible disk. Is done.

[0004] As a method of recording a servo signal on a flexible disk, a hub of the flexible disk is held by a spindle for rotational drive with setting a disk cartridge on a servo track writer, and a magnetic head is mounted on the flexible disk. Then, a method of writing a servo signal while moving the magnetic head in the radial direction of the flexible disk while rotating the flexible disk by the spindle is generally performed (for example, Japanese Patent Laid-Open No. 9-180).
No. 418).

In writing servo signals to a large-capacity flexible disk, the flexible disk is rotated at a high speed of, for example, 2400 rpm or 3600 rpm to shorten the processing time. that time,
The write start position of the servo signal is determined based on the clock signal, a clock disk is installed coaxially with the spindle that drives the flexible disk, and the clock signal is recorded and reproduced on this clock disk by a clock head. A device that detects a reference position of an angle is known.

An air bearing spindle motor is used to stably obtain high-speed rotation of the spindle. That is, the spindle is supported in a low friction state by the pressurized air supplied to the air bearing portion, and is rotated at a high speed by driving the motor.

[0007]

However, in the above-described air bearing spindle motor, the gap between the bearing portions becomes unstable unless a prescribed air pressure is constantly applied to the air bearing portions. If the air pressure is significantly reduced, the gap cannot be partially maintained, and the metal of the spindle and the bearing may collide with each other, resulting in wear and damage.

[0008] By the way, it is necessary to supply pressurized air from an air source (compressor) through a clean air unit in addition to a power source to a servo track writer. It is not preferable because it affects the quality, and clean air is sent from an air source installed at a distant position through a pipe. If the supplied air is cut off or the pressure drops for some reason, the gap in the air bearing portion of the spindle cannot be maintained as described above, resulting in damage to the spindle.

In particular, the air bearing spindle motor is expensive, and it is advantageous in terms of cost to have a long life so that it can be used for a long time. In addition, the maintenance time accompanying the replacement of the spindle is the operation time for writing the servo signal. And the occurrence of troubles due to the decrease in the pressure of the supply air is a serious problem.

In view of the above, the present invention has been made in view of the above points, and does not provide a servo track writer which prevents breakage due to a decrease in pressure of air supplied to an air bearing portion of a spindle in writing a servo signal. It is assumed that.

[0011]

A servo track writer according to the present invention, which has solved the above-mentioned problems, holds a flexible disk on a spindle of a rotary drive means and rotates the disk at a predetermined rotational speed. In a servo track writer that writes a servo signal, the spindle is supported by pressurized air supplied to an air bearing unit, and a pressure detecting unit that detects supply pressure is provided in an air passage that supplies pressurized air to the air bearing unit. Provided, based on the detection of the pressure detecting means,
Control means for stopping the driving of the rotary driving means when the supply pressure falls below a predetermined value is provided.

The pressure detecting means is constituted by an air pressure switch or the like, and the control means is constituted by a cutoff circuit or the like.

It is desirable that a backup air tank be interposed in the air passage. The capacity of this air tank must be at least an amount capable of supplying pressurized air of a specified pressure or more to the air bearing portion with respect to the time from the drive stop operation of the rotary drive means to the actual stop of the spindle, and preferably at least twice as much. With a capacity of The air tank configuration is such that clean and dry air can be supplied.
Further, a check valve or a shutoff valve is provided in the air passage on the upstream side of the air tank.

[0014]

According to the present invention as described above, the servo signal is written by holding the flexible disk on the spindle of the rotary drive means and rotating it at a predetermined rotation speed.
By providing control means for stopping the driving of the rotary drive means when the supply pressure falls below a predetermined value by detection of pressure detection means provided in the air passage for supplying pressurized air to the air bearing part of the spindle, Even if the supply of air is cut off due to a failure of the air source, breakage of the piping, etc., the rotation of the spindle is immediately stopped to prevent damage to the spindle, preventing serious damage and reducing cost. In addition, the maintenance time can be reduced and the processing efficiency can be improved.

If a backup air tank is provided, the supply of pressurized air at a pressure equal to or higher than a specified pressure to the air bearing portion until the rotation is stopped can be secured, and damage can be prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is a schematic diagram showing a servo track writer according to one embodiment of the present invention.

The servo track writer 1 is provided with a flexible disk 2
1 is provided with a spindle 31 which is driven to rotate by a rotation driving means 3 having a motor or the like. The spindle 31 protrudes from the upper end of an air spindle device 30 (air bearing spindle motor) installed on the surface plate 9, and the upper end thereof has a hub 22 ( A center pin 33 protruding into a center hole of the center core is provided, and an upper end surface thereof is formed as a receiving surface (reference surface) of the hub 22, and a hub chuck 32 for chucking by a magnetic attraction force or the like is provided. Spindle 3
With the rotation of 1, the hub 22 and the flexible disk 21 chucked by the hub chuck 32 are kept at a predetermined high-speed rotation (for example, 3600 rpm).

In the disk cartridge 2, the flexible disk 21 is rotatably housed in a cartridge case 23 indicated by a chain line, and although not shown, windows for inserting a magnetic head are provided on the upper and lower surfaces of the cartridge case 23. The magnetic heads 6, 7, which will be described later, pass through the windows, and the lower surface (0 surface) and the upper surface (1
Surface), and a shutter member for opening and closing the window is slidably installed. A liner made of nonwoven fabric or the like is provided on the inner surface of the cartridge case 23 so as to face the upper and lower surfaces of the flexible disk 21.

A clock disk 41 of a hard disk is installed on the spindle 31 coaxially with the flexible disk 21. A clock signal (reference pulse) is recorded and reproduced on the clock disk 41 by a clock head 42, and the rotation angle of the flexible disk 21 is determined. The timing detecting means 4 for detecting the reference position is constituted.
Clock disk 41 and clock head 42
A known hard disk drive can be used, and the clock head 42 is attached to a support member 43 installed on the base 9. An upper cover 45 surrounding the outer periphery of the timing detecting means 4 is provided above the surface plate 9, and the spindle 31 projects through an opening on the upper surface of the upper cover 45.

The air spindle device 30 for rotating the spindle 31 includes an air bearing portion (not shown) for supporting the spindle 31 and a motor for rotating the spindle 31. An air introduction portion 35 is provided at the bottom located below the surface plate 9, and an air passage 8 (air pipe) from an air source (clean air unit) (not shown) is connected to the air introduction portion 35 so that clean air is supplied. Pressurized air is supplied to the air gap of the air bearing part, and pressurized air of a specified pressure or more is supplied. The compressed air holds the air gap and rotatably supports the spindle 31 with the bearing in a low friction state. It is supposed to.

The air passage 8 is provided with a pressure detecting means 81 such as an air pressure switch for detecting a supply pressure at an upstream portion, and a detection signal of the detecting means 81 is sent to the control means 100. The control means 100 includes a shutoff circuit and the like, and stops the motor drive of the rotation drive means 3 when the supply pressure falls below a predetermined value based on the detection of the pressure detection means 81.

The air passage 8 has a pressure detecting means 8
An air tank 83 for backup is provided downstream of 1 through a check valve 82. The air tank 83 accumulates pressurized air, and when the supply air is shut off or the pressure drops,
This is for ensuring the supply of air to the air bearing portion. The tank capacity must be at least an amount capable of supplying pressurized air of a specified pressure or more to the air bearing portion with respect to the time from the drive stop operation of the rotary drive means 3 to the actual stop of the spindle 31, and preferably twice that amount. It has the above capacity. The configuration of the air tank 83 is such that clean and dry air can be supplied. The check valve 82 closes when the pressure on the upstream side drops, and prevents the air in the air tank 83 from flowing out to the upstream side. Note that this check valve 82 is
A shut-off valve that closes based on the detection of the pressure detecting means 81, a shut-off valve that closes in response to a decrease in pilot pressure, or the like may be used.

A discharge air passage 8 for discharging air passing through the air bearing portion of the spindle 31 is connected to a side surface of the air spindle device 30 located below the platen 9. The other end of the discharge air passage 36 is connected to an air supply port formed through the platen 9, and clean air is supplied into the upper cover 45. As a result, the storage space for the clock disk 41 and the clock head 42 in the upper cover 45 has a clean air environment, and the inside is pressurized by the supply of pressurized air to maintain a clean environment. Excess air is discharged from the outer peripheral portion of the upper spindle 31 and the like.

The clean air supplied to the air spindle device 30 is, for example, 100 pieces / size of 0.3 μm or more in cleanness / (30.48 cm) ³ or less, and the flow rate is 1.6 L / mi.
n (0.583 Nm ³ / h).

A signal writing means 5 for writing a servo signal is provided on the surface plate 9 (anti-vibration table). Signal writing means 5
Is provided with an upper (one surface side) magnetic head 6 and a lower (0 surface side) magnetic head 7 which are arranged so as to sandwich the flexible disk 21 and are vertically opposed to each other. It is attached to the base 53. The head base 53 is supported by a linear guide 52 on a base 51 installed on the surface plate 9 so as to be able to reciprocate toward the center of the spindle 31, and is driven along with the linear guide 52 by driving a VCM (voice coil motor) 54. In addition to the moving operation, the stop positions of the magnetic heads 6 and 7 are accurately controlled by the position control using the laser length measuring device 10.

The laser length measuring device 10 is provided with a reflector 11 on the head base 53 for detecting the positions of the magnetic heads 6 and 7 from the position of the head base 53. The reflector 11 is provided from the laser transducer 12 via the half mirror 13. Is irradiated with laser light, the reflected light is incident on the receiver 14 via the half mirror 13, the position is detected by the length measurement, and sent to the control means 100. Loads, unloads, seek operations, and the like of the magnetic heads 6 and 7 are performed by control according to the length measurement.

The magnetic heads 6 and 7 on both sides are opened and closed by a known load mechanism (not shown) such as dynamic loading in response to driving of the VCM 54, and the flexible disk 21 in the disk cartridge 2 set on the spindle 31. And is unloaded to the retracted position retracted from this position. The upper magnetic head 6 and the lower magnetic head 7 include head portions 6b, 7b each having a head core having a head gap at the tip of suspensions 6a, 7a.
(Slider) is fixed. The heads 6b, 7
b is urged by a spring urging force of the suspensions 6a and 7a toward the surface of the flexible disk 21 with a weak force,
The air bearing portion floats due to the airflow generated by the flexible disk 21 rotating at a high speed, so that a predetermined gap is maintained between the head gap and the surface of the flexible disk 21.

The disk cartridge 2 is loaded and set into the spindle 31 from above by a supply mechanism such as a robot. The magnetic heads 6, 7 are inserted into a magnetic head insertion window opened by a shutter opening / closing mechanism.
Is loaded / unloaded.

The control unit 100 controls the rotation of the spindle 31, that is, the flexible disk 21, by the rotation driving unit 3, generates a servo signal to be written by the signal writing unit 5, and controls the writing of the servo signal. The control means 100 also controls the drive of the VCM 54 in accordance with the detection of the clock signal. The control means 100 includes a clock signal for detecting the rotational position of the flexible disk 21 by the clock head 42 of the timing detection means 4, a signal of the laser length measuring device 10, Other detection signals are input.

Next, the writing operation of the servo signal of the servo track writer 1 will be described. First, the disk cartridge 2 is supplied by a robot or the like, and the hub 22 of the flexible disk 21 is held by the hub chuck 32 of the spindle 31. Further, the shutter member is opened by the opening / closing mechanism, and the signal writing means 5 is loaded into the magnetic head insertion window opened on the upper and lower surfaces of the cartridge case 23.

The spindle 31 is rotationally driven at a predetermined rotational speed, for example, 3600 rpm by the operation of the rotary driving means 3 based on a command from the control means 100.
The flexible disk 21 set in is rotated. The loading operation of the magnetic heads 6 and 7 is controlled by the control unit 100.
The drive signal is output to the VCM 54 based on the command of the above, and the head base 53 is moved in the forward direction. Accordingly, the upper and lower suspensions 6a and 7a are operated to open outward by the operation of the load mechanism. In this state, the head base 53 moves forward, and the head portions 6b and 7b at the leading ends pass over the front end of the cartridge case 23. When it comes to the position facing the window,
The magnetic heads 6 and 7 are operated so that the surfaces of the heads 6 b and 7 b approach the flexible disk 21. The magnetic heads 6 and 7 in the loaded state are head parts 6b and 7
b is urged toward the flexible disk 21 by the uniform urging force of the upper and lower suspensions 6a and 7a, but floats by an air current generated by the rotation of the flexible disk 21 to maintain a predetermined gap. As a result, the servo signal can be written.

Next, a servo signal is written. First, the head gap between the upper and lower magnetic heads 6 and 7 is changed by controlling the position of the VCM 54 to the flexible disk 2.
1 at a predetermined radial position (a track position where a servo signal is first written), and a servo signal is written to the servo track one round from a predetermined reference point receiving a clock signal from the clock head 42. After the writing of the servo signal to this servo track is completed, the seek operation of the magnetic heads 6 and 7 to the next servo track is performed, and upon receiving the next clock signal, the servo signal is transferred to the next servo track by one.
Write around. In this manner, while synchronizing with the clock signal, the seek operation and the write operation of sequentially sending the magnetic heads 6 and 7 from the outer periphery to the inner periphery (or from the inner periphery to the outer periphery) of the flexible disk 21 by a predetermined distance corresponding to the servo track pitch are repeated. Perform servo write.

When the servo writing of all the predetermined servo tracks and other processes are completed, the magnetic heads 6 and 7 are unloaded to be evacuated from the disk cartridge 2. In the unloading operation, the magnetic heads 6 and 7 are opened by the operation of the load mechanism accompanying the head base 53 moving backward by driving the VCM 54. In this state, the head base 53 further moves backward and the head part 6b at the tip end is opened. , 7
b moves to the outer position beyond the front end of the cartridge case 23 and retreats to the retracted position. After the rotation of the spindle 31 is stopped, the processed disk cartridge 2 is held and removed by a robot or the like, and a new disk cartridge 2 is set on the spindle 31 to perform servo writing in the same manner.

In the above-described servo write, if the pressure of the pressurized air supplied to the air bearing device 30 drops below a specified value during the servo write, control is performed based on a signal from the pressure detecting means 81 which detects this. The means 100 interrupts the supply of power to the motor of the rotation driving means 3 and immediately performs a stop operation to stop the rotation of the spindle 31.
In this pressure drop state, the check valve 82 closes and the pressurized air stored in the air tank 83 is sent to the air spindle section, and the spindle 31 and the bearing section rotate while maintaining the air gap. Prevents contact and prevents failure. Thereby, the service life of the air spindle device 30 is prolonged and the operation efficiency is improved, which is advantageous in cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a servo track writer according to one embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Servo track writer 2 Disk cartridge 3 Rotation drive means 4 Timing detection means 5 Signal writing means 6, 7 Magnetic head 8 Air passage 9 Surface plate 10 Laser length measuring device 21 Flexible disk 22 Hub 30 Air spindle device 31 Spindle 32 Hub chuck 35 Air inlet 36 Discharge air passage 41 Clock disk 42 Clock head 81 Pressure detecting means 82 Check valve 83 Air tank

Claims (2)

[Claims] 1. A servo track writer for holding a flexible disk on a spindle of a rotary drive means and rotating the flexible disk at a predetermined rotation speed, and writing a servo signal to the rotating flexible disk by a magnetic head, wherein the spindle supplies the air bearing. Pressure detecting means for detecting a supply pressure is provided in an air passage which is supported by the pressurized air to be supplied and supplies the pressurized air to the air bearing portion. A servo track writer comprising control means for stopping the driving of the rotary driving means when the rotation speed has decreased. 2. The servo track writer according to claim 1, wherein a backup air tank is interposed in the air passage.