JPH0833981B2 - Head cleaning method - Google Patents

Description

DETAILED DESCRIPTION [Overview] In a magnetic disk device including a sensor that detects contact between a head and a magnetic disk medium, it is recognized that dust is attached to the head based on a signal from the sensor,
Regarding a head cleaning method for cleaning a head in a cleaning area provided on a magnetic disk medium, for the purpose of improving the reliability of a magnetic disk device, a magnetic device equipped with a detection means for detecting contact between the head and the magnetic disk medium In the disk device, the head is provided on the magnetic disk medium when the detecting means detects that the head comes into contact with the magnetic disk medium while the magnetic disk medium is rotating at a predetermined speed. Control for positioning in the cleaning area, control for slightly vibrating the head in the inner and outer peripheral directions of the magnetic disk medium within the cleaning area, and setting the rotational speed of the magnetic disk medium to a predetermined speed. When a control unit is provided for controlling to lower the head, and the head arrives at the cleaning area of the magnetic disk medium,
By reducing the rotation speed of the magnetic disk medium, the head is brought into contact with the cleaning area, and then the head is vibrated slightly.

[Industrial applications]

The present invention relates to a magnetic disk device provided with a sensor for detecting contact between a head and a magnetic disk medium, and in particular, based on a signal from the sensor, recognizes that dust is attached to the head, and provides the magnetic disk medium with the dust. The present invention relates to a head cleaning method for cleaning a head in a cleaning area.

The head of the magnetic disk device is in contact with the surface of the magnetic disk medium when the power is off, and when the magnetic disk device is powered on and the magnetic disk medium starts rotating, it floats.

Some magnetic disk devices include a sensor for detecting contact between the magnetic disk medium and the head. Until the head floats, a signal for notifying that the head is in contact is sent.

That is, when the head is in contact with the magnetic disk medium, it vibrates, but this vibration is detected and converted into an electrical signal.
A circuit using an (Acoutic Emission) element (for example, Japanese Patent Laid-Open No. 61-227220) is known.

By the way, although dust may adhere to the head, when dust adheres to the head, even if the head is flying, the flying gap is small, so that not only the characteristics of the head deteriorate but also the surface of the magnetic disk medium May cause damage. When the surface of the magnetic disk medium is damaged, the dust generated due to this enters the flying gap between the head and the magnetic disk medium one after another, causing a so-called head crash, so the dust attached to the head is quickly detected and cleaned. It is necessary.

[Conventional technology]

There is a strong demand for miniaturization and large capacity of the magnetic disk device, and as the recording density improves, the flying height of the head decreases, and along with this, the head and the magnetic disk medium are sealed to prevent dust from entering. Is manufactured in a clean environment to prevent dust from adhering to the head. Therefore, there is no means for detecting that dust is attached to the head and cleaning the head.

[Problems to be Solved by the Invention]

As described above, conventionally, there is no means for cleaning the head by detecting that dust has adhered to the head, so once dust adheres to the head, it is used as it is, so the characteristics of the head only deteriorate. Finally, there is a problem that a head crash finally occurs and it becomes unusable.

In view of such problems, the present invention uses a sensor that detects that the head is in contact with the magnetic disk medium,
An object of the present invention is to detect the adhesion of dust to the head and clean the head in a cleaning area provided on the magnetic disk medium to improve the reliability of the magnetic disk device.

[Means for solving the problem]

 FIG. 1 is a block diagram of the principle of the present invention.

When the power supply is turned on, the control means 1 controls the motor drive circuit 7 to drive the spindle motor 8 and rotate the magnetic disk medium 9. A signal notifying the rotation speed is sent from the spindle motor 8 to the motor drive circuit 7, and the motor drive circuit 7 sends this signal to the control means 1. Therefore, the control means 1 causes the magnetic disk medium 9 to reach the specified rotation speed. Recognize what you have done.

The control means 1 monitors the signals sent from the detection means, that is, the sensors 10 to 12, and after the magnetic disk medium 9 reaches the specified rotation speed, the data head 13 or the servo head 14 of the sensors 10 to 12 is detected. When any one of them sends a signal in contact with the magnetic disk medium 9, it is determined that dust is attached to the head equipped with the sensor that sent the signal.

That is, the data head 13 and the servo head 14 float as the air pressure rises as the magnetic disk medium 9 starts to rotate and the rotation speed increases. The heads vibrate, and the sensors 10 to 12 detect the vibration.

However, if the head floats, the vibration stops and the sensor 10
No signal is sent from ~ 12 to notify the contact. Therefore, when the magnetic disk medium 9 is rotating at the specified rotation speed and any one of the sensors 10 to 12 notifies the contact, dust enters the floating gap of the corresponding head, As if the head is in contact with the magnetic disk medium 9,
This is to show that it is vibrating.

When the magnetic disk medium 9 reaches a specified rotational speed and then sends a contact signal from the sensors 10 to 12 when the control means 1 is connected to a higher-level device, the control means 1 releases the connection and then the servo. The control circuit 2 is instructed to position the head in the cleaning area provided on the magnetic disk medium 9.

The servo control circuit 2 drives the motor 5 via the amplifier circuit 3 in order to position the head in the cleaning area based on the servo information of the servo surface of the magnetic disk medium 9 read by the servo head 14 input via the demodulation circuit 4, Carriage 6
To move.

In the magnetic disk medium 9, for example, a cleaning area is provided on the outer peripheral side, and if the area indicated by is the cleaning area and the area indicated by is the data area, the cleaning area is provided at the boundary between the data area on the servo surface and the cleaning area. The information shown is recorded.

The servo control circuit 2 recognizes from the servo information read from the servo surface that the servo head 14 is in the data area, and controls the motor 5 to move the carriage 6 to the outer peripheral side of the magnetic disk medium 9. When the arrival of the cleaning area is recognized from the cleaning area information, the servo head 14 is further moved by a predetermined distance from the recording position of the cleaning area information, and then the driving of the motor 5 is stopped. That is, the servo head 14 is positioned near the center of the cleaning area.

When the positioning of the head with respect to the cleaning area is completed, the control means 1 controls the motor drive circuit 7 to reduce the rotation speed of the spindle motor 8 to a predetermined speed. That is, the head is lowered so as to rotate at a low speed so as not to fly.

When the control means 1 recognizes that the rotation speed of the magnetic disk medium 9 has become a low speed rotation via the motor drive circuit 7,
In order for the carriage 6 to slightly vibrate with respect to the servo control circuit 2, for example, an AC signal is passed through the amplifier circuit 3 and the motor 5
To send.

Therefore, since the data head 13 and the servo head 14 contact the magnetic disk medium 9 in the cleaning area of the magnetic disk medium 9 and are shaken in the outer peripheral direction and the inner peripheral direction of the magnetic disk medium 9, dust is generated. To be cleaned.

[Action]

With the configuration as described above, the control means 1 is a sensor.
When you receive a signal from 10 to 12 that dust is attached to the head,
The head is positioned in the cleaning area of the magnetic disk medium 9, the spindle motor 8 is controlled to reduce the rotational speed of the magnetic disk medium 9 so that the head does not fly, and then the carriage 6 is slightly vibrated.
13 and the servo head 14 are cleaned in the cleaning area of the magnetic disk medium 9.

Therefore, the characteristics of the head are prevented from deteriorating and the surface of the magnetic disk medium 9 is prevented from being damaged, so that it is possible to prevent the magnetic disk device from becoming unusable due to the head crash.

〔Example〕

FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. 3 is a flow chart for explaining the operation of FIG.

The same reference numerals as those in FIG. 1 denote the same functions. When the power is turned on, the processor 15 reads the program stored in the ROM 16 and operates, controls the motor drive circuit 7 through the input / output port 17, and drives the spindle motor 8 as shown in FIG. The magnetic disk medium 9 is rotated, and it is checked whether the rotation speed has reached a specified rotation speed.

The processor 15 waits for the rotation speed of the magnetic disk medium 9 to reach the specified rotation speed, and as shown in FIG. 3, the head contacts the magnetic disk medium 9 via the input / output port 17 from the sensors 10-12. Check that the signal is being sent.

If no contact signal is sent, move to another process,
When this processing is completed, the routine returns to the routine for monitoring the transmission of the contact signal, but if the contact signal is transmitted, the third
As shown in the figure, it is checked through the input / output port 17 whether the host device is connected. If it is coupled with the host device, the coupling with the host device is released, and if it is not coupled with the host device, the head movement is started immediately.

That is, as described with reference to FIG. 1, the processor 15 causes the servo control circuit 2 via the input / output port 17 to move the servo head 14 from the data area of the magnetic disk medium 9 to the cleaning area and position it in the cleaning area. Give instructions.

As shown in FIG. 3, the processor 15 waits for notification from the servo control circuit 2 that the servo head 14 has been positioned in the cleaning area via the input / output port 17, and the servo head 14 is positioned in the cleaning area. Then, as shown in FIG. 3, the rotation speed of the spindle motor 8 is reduced.

When the processor 15 recognizes that the rotation speed of the spindle motor 8 has become a predetermined low speed rotation via the input / output port 17, it causes the carriage 6 to vibrate slightly as described with reference to FIG. Then, as shown in FIG. 3, after a lapse of a predetermined time, the rotation speed of the spindle motor 8 is again increased to a specified speed, and then the servo head 14 is positioned in the data area.

Then, the process returns to the routine for checking whether the sensors 10 to 12 have transmitted the contact signal.

〔The invention's effect〕

As described above, according to the present invention, when dust adheres to the head, the adhered dust can be immediately cleaned, so that the characteristic deterioration of the head and the occurrence of head crash can be prevented, and the reliability of the magnetic disk device can be improved. Can be done.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. 3 is a flow chart for explaining the operation of FIG. In the figure, 1 is a control means, 2 is a servo control circuit, 3 is an amplifier circuit, 4
Is a demodulation circuit, 5 is a motor, 6 is a carriage, 7 is a motor drive circuit, 8 is a spindle motor, 9 is a magnetic disk medium, 10 to 12 are sensors, 13 is a data head, 14 is a servo head, 15 is a processor, 16 Is a ROM and 17 is an input / output port.

Claims (1)

[Claims] 1. Detecting means (10) (11) (12) for detecting contact between a head (13) (14) and a magnetic disk medium (9).
In a magnetic disk device equipped with, when the magnetic disk medium (9) rotates at a predetermined speed, the heads (13) (14) cause the magnetic disk medium (9) to move.
Control for positioning the heads (13) (14) in a cleaning area provided on the magnetic disk medium (9) when the detection means (10) (11) (12) detect contact with In the cleaning area, the heads (13) (14) are slightly vibrated in the inner peripheral direction and the outer peripheral direction of the magnetic disk medium (9), and the rotational speed of the magnetic disk medium (9) is preset. The head (13) is provided in the cleaning area of the magnetic disk medium (9) by providing a control means (1) for controlling the speed to a predetermined speed.
When the magnetic recording medium (9) arrives, the rotational speed of the magnetic disk medium (9) is reduced to bring the heads (13) and (14) into contact with the cleaning area, and then the heads (13) and (14). A head cleaning method characterized by micro-vibration.