JPH0192986A - Servo signal writer for magnetic disk device - Google Patents

Abstract

PURPOSE:To obtain a system with less write error and high productivity by reducing an enclosed package with a servo signal writer stored therein in writing position information by a prescribed pressure. CONSTITUTION:A servo signal writer consists of a write head 1 writing a position signal to a servo disk 8 of a magnetic disk device 7, a carriage 2 supporting the head 1, a position detection section 3, and a base 4 supporting the carriage 2 and the magnetic disk device 7. Moreover, the device is stored in an enclosed package 5, the pressure is reduced by a vacuum pump 6 to keep a prescribed pressure. Since the write head 1 is not susceptible to the effect of air flow by the reduction in air molecules due to the pressure reduction, the vibration is less. Since the magnetic disk device 7 is driven at a real operating number of revolutions, the position deviation attended with the difference from the number of revolutions is not caused. Thus, the position information is written with less write error, the system is effective to improve the position accuracy and the recording density.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a servo signal writing device for recording positional information on a specific disk surface in a magnetic disk drive, and particularly to the production of a magnetic disk drive with little positioning error. Regarding the method.

[Conventional Technology] ゛In current magnetic disk drives, position information is recorded in advance on a specific disk surface as a servo surface, and during positioning, it is recorded on the servo surface using a read-only servo head. A common method is to read out the location information and use it for positioning. Therefore, in the production of magnetic disk drives, after a magnetic disk is installed in a spindle, position information is recorded on this specific servo surface before a magnetic head is installed. A servo signal writing device performs this work.

Since all positioning in a magnetic disk drive is performed based on position information written on the servo surface, positioning errors that occur when writing position information directly appear as positioning errors in the magnetic disk drive. Therefore, the mechanism W6 of the servo signal writing device is all made with precision on the order of microns, and is designed to write position signals at predetermined positions. However, since the part that writes signals uses a floating head, which is the same as in general magnetic disk drives, the support spring for the write head vibrates due to the air flow accompanying the rotation of the disk.

Furthermore, since a magnetic disk rotating at high speed performs a so-called oscillating motion, although minute, the trajectory of the head on the surface of the magnetic disk is not a perfect circle, but is circular.

Such head and disk vibrations cause positional deviation during writing, so it is recommended to lower the disk rotation speed to weaken the air flow and disk vibration accompanying rotation.
As shown in Publication No. 09, measures have been taken to reduce this by providing a rectifying plate or the like.

[Problem that the invention seeks to solve]

The above conventional technology has the following problems. Generally, disk vibration changes with the disk rotation speed. Therefore, in the case of the method of lowering the disk rotational speed when writing positional information, the disc vibration at the actual rotational speed, that is, the amount of positional deviation under the disk device usage conditions, and the disk vibration at low rotational speed, that is, when writing positional information. Due to different amounts,
Even if the write head does not vibrate, misalignment can occur. In particular, as the recording density further increases and the density in the track direction becomes narrower, the amount of positional deviation cannot be ignored. In addition, in the case of the method of providing a rectifying plate as in the above publication, it is effective for application to magnetic disk drives, but in the case of the servo signal writing device, productivity decreases and the structure is deteriorated because installation is done by removal. There were problems such as complexity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a servo signal writing device with less writing errors and high productivity.

[Means for solving problems]

The above object is achieved by reducing the pressure of the sealed container containing the servo signal writing device to a constant pressure when writing position information.

[Effect]

By reducing the pressure inside the closed container, the amount of air molecules existing at the interface between the magnetic disk and the write head for writing servo signals is reduced, so the air flow rate per unit time, that is, the wind speed is reduced.

Therefore, as in the case where the disk rotation speed is lowered, the air flow hitting the support spring of the write head is weakened compared to the case under normal pressure, and writing errors due to vibration of the write head are reduced. Furthermore, since the disk rotation speed is set to be the same as when the magnetic disk device is actually used, no positional deviation occurs due to a difference in the rotation speed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The servo signal writing device includes a write head 1 that writes position signals to the servo disk 8 of the magnetic disk device 7. A carriage 2° that holds the light head 1; a position detection unit 3 that positions the carriage 2 at a preset position; and a carriage 2. It consists of a base 4 that holds a magnetic disk device 7. In addition, the above device has an airtight container 5
The pressure is reduced by a vacuum pump 6 to maintain a constant pressure. The pressure is monitored by a pressure gauge 9 and maintained at a constant low pressure.

Writing of the position signal is performed by the following procedure.

First, the magnetic disk device 7 is held at a predetermined position on the base 4. Next, the magnetic disk device 7 is driven by a drive unit (not shown) at the actual rotation speed, and after the magnetic disk reaches steady rotation, the write head 1 is loaded.

After that, the vacuum pump 6 is operated to reduce the pressure inside the closed container 5 and maintain it at a constant pressure, and then the write heads 1 are sequentially positioned at predetermined positions and position information is written on the servo disk surface 8.

The light head 1 is less susceptible to the influence of airflow due to the reduction in air molecules due to reduced pressure, so vibrations are small.

Furthermore, since the magnetic disk device 7 is driven at the actual rotation speed, positional deviations due to differences in rotation speed do not occur. Therefore, positional information can be written with little writing error.

〔Effect of the invention〕

According to the present invention, since positional information can be written with little writing error, it is effective in improving positioning accuracy and recording density in magnetic disk drives.

[Brief explanation of the drawing]

The figure is a sectional view showing one embodiment of the present invention. 1...Light head, 2...Carriage, 3
...Position detection unit, 4...Base, 5...Airtight container, 6...Vacuum pump, 7...Magnetic disk device, 8...Servo disk, 9...Pressure gauge.

Claims (1)

[Claims] 1. A write head for writing a position signal on a magnetic disk, a carriage and a position detection section for positioning the write head at a predetermined position, and a base for holding the carriage, the position detection section, and a magnetic disk device for writing the position signal. 1. A servo signal writing device for a magnetic disk device comprising a servo signal writing device for a magnetic disk device, wherein the device is housed in an airtight container and the pressure inside the container is reduced when writing a position signal.