JPH01311481A - Magnetic head device - Google Patents

Abstract

PURPOSE:To always obtain the optimum contact state of a head by setting contact pressure on a head chip in a seek mode for a recording medium less than that in a recording and reproducing mode. CONSTITUTION:The title device is controlled in such a way that a driving voltage Vc in the recording and reproducing mode is set higher than a driving voltage Vb in the seek mode, and the quantity of displacement of a bimorph plate 8 in the recording and reproducing mode is set larger than that in the seek mode, and the height of the head 1 in the recording and reproducing mode is set less than that in the seek mode. And control is applied so that the contact pressure on the surface SF of the recording medium MD of the head 1 in the seek mode is set less than that in the recording and reproducing mode. Therefore, it is possible to prevent damage due to the movement of the head in the diameter direction of a disk in the seek mode from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a magnetic head device, and particularly to a magnetic head device for recording and reproducing data on and from hard disks, flexible disks, and the like.

B1 Summary of the Invention The present invention provides a magnetic head device capable of controlling the height position from the medium recording surface of a head chip that moves relative to a magnetic recording medium such as a hard disk. Depending on the mode switching between the reproduction mode and the so-called seek mode for searching the recorded contents of the magnetic recording medium, the height position control of the head chip is changed to vary the contact pressure against the magnetic recording medium, and the seek By controlling the contact pressure in mode to be smaller than the contact pressure in recording/reproducing mode, the head chip can be moved in the same direction as the recording/reproducing direction on the magnetic recording medium and in a direction different from the recording/reproducing direction. The purpose is to obtain the optimum contact condition when moving the object and when moving the object.

C2 Prior Art For example, when a contact type magnetic head is used for a flexible disk such as a so-called stretched sheet disk, the head is constantly in contact with the disk, which causes problems such as the service life of the magnetic head. In addition, in hard disks, etc., the head height in a steady state when the disk is rotating at high speed, the so-called flying high (FH), is stable, but the head slides against the disk at the start and end of rotation. Therefore, there is a problem.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 60-83280, when a magnetic disk such as a hard disk is stopped, the head (slider) is held away from the magnetic disk surface, and the magnetic disk is rotated. A method has been proposed in which the head (slider) is then controlled to be displaced in a direction so as to come into contact with the disk. In this case, the head is placed at a height where there is no risk of contacting the disk when the disk starts or stops rotating, and after the disk reaches steady rotation, the head is moved in the direction of contact with the disk. At this time, the so-called air film effect or the like causes the head (slider) to float at a predetermined height above the disk surface, thereby preventing problems such as damage to the magnetic disk or the magnetic head, or shortened lifespan.

D0 Problems to be Solved by the Invention Incidentally, in magnetic recording media such as hard disks and the above-mentioned flexible disks, a so-called seek operation for searching a recording trunk, etc. occurs along with signal recording and reproducing operations in a -S manner. is required, and in this case the magnetic head is
It moves in a direction substantially perpendicular to the track direction, which is the recording/reproducing direction, that is, in the radial direction of the disk.

However, during such a seek operation, if the head remains in the same state of contact as during the above-mentioned recording and playback operations,
The head may become unstable due to the disturbance of the air film, and the head may slide against the disk surface, causing damage.

The present invention has been made in view of the above circumstances, and provides a magnetic head device that can prevent damage caused by head movement during seek operation mode and achieve optimal head contact state during any operation mode. The purpose is to provide.

Means for Solving Problem E1 In order to solve the above problems, the magnetic head device according to the present invention uses a magnetic head chip that magnetically records or reproduces signals while moving relative to a magnetic recording medium. and,
height position control means for controlling the height position of the magnetic head chip in a direction perpendicular to the recording surface of the magnetic recording medium; and at least a mode for recording or reproducing signals on the magnetic recording medium; a switching circuit that switches and controls the height position control means in a seek mode for searching recorded content, and controls the contact pressure of the magnetic head chip against the magnetic recording medium in the seek mode to
It is characterized by less control than in playback mode.

21 Effect By reducing the contact pressure of the magnetic head chip against the magnetic recording medium during the recording/reproducing mode, the contact pressure of the head chip during the seek mode is reduced, so that the head chip moves on the magnetic recording medium in the same direction as the recording/reproducing direction. When moving to
Optimum head contact conditions can be obtained when moving in a direction different from the recording/reproducing direction.

G. Example Hereinafter, an example of a magnetic head device according to the present invention will be described with reference to the drawings.

In FIG. 1, a magnetic head chip 1 for magnetically recording or reproducing signals is attached to protrude from the tip of a head support plate 2, and this support plate 2 supports the head via parallel plate springs 3.4. It is attached to the head mounting base 5 so as to be movable in the direction of arrow A, which is the protruding direction. The direction of arrow A is perpendicular to the recording surface SF of the magnetic recording medium MD, such as a so-called hard disk. A mounting hole 6 is bored in the head mounting base 5, and the mounting hole 6 can be used to attach to a head drive mechanism or a so-called hesodoboshitanner (not shown). In FIG. 1, the moving direction (recording and reproducing direction) of the magnetic recording medium MD such as a hard disk is in the direction of arrow B, and recording tracks are formed along this direction of arrow B.

Further, the head drive mechanism and the like move in a direction substantially perpendicular to the direction of the arrow B on the recording surface SF of the magnetic recording medium MD.
That is, in the direction perpendicular to the paper surface of Figure 1 (in the direction of arrow C, which will be described later).
The head is moved to perform a so-called seek operation and tracking operation such as recording track search.

Next, a proximal end portion of a bimorph plate 8, which is an electro-mechanical conversion element, is fitted and fixed in the notch portion 7 of the head mounting base 5 on the side facing the head support plate 2. The tip of the bimorph plate 8 is guided and inserted into a notch 9 provided on the side of the head support plate 2 with an appropriate gap.

Here, the parallel plate spring 3.4 has a plate thickness of about 20 to 4
0 μm, and about 600 μm for the bimorph plate 8.
I use each of them. Therefore, when the spring restoring force of the bimorph plate 8 is sufficiently larger than the spring restoring force of the parallel plate springs 3.4 and no driving voltage is applied to the bimorph plate 8, the bimorph plate 8
The head support plate 2 is pushed upward in the figure only by the restoring force of the spring, and the magnetic head chip 1 is moved onto the magnetic recording medium M such as a disk.
It is placed at a height position of a predetermined path Md from the surface SF of D.

The head height d at this time is set to such a height that there is no risk that the magnetic head chip 1 will come into contact with the recording surface SF when the rotation of the magnetic recording medium MD such as a hard disk starts or stops.

Furthermore, the bimorph plate 8 is configured so that at least two different drive voltages can be applied to it, in addition to the state in which no drive voltage is applied.

As a basic configuration for this purpose, a three-position switching switch 11 and two drive voltage sources 12 and 13 are provided, one of the electrodes on both surfaces of the bimorph plate 8 is grounded, and the other is connected to the changeover switch 11. connected to the common terminal of Of the three selected terminals a, b, and c of the changeover switch 11, terminal a is open (or grounded), and the drive voltage source 12 is connected to the terminal, and the drive voltage source 13 is connected to the terminal C, respectively. are connected to the surface electrodes of the bimorph plate 8 to receive a voltage Vb from these drive voltage sources 12, l"3.
, Vc can be supplied. Changeover switch 1
1 is a terminal a when starting or stopping the rotational drive of a hard disk, etc., which is a magnetic recording medium MD.
In addition, the head height control state in the seek mode is connected to the terminal C in the so-called seek mode, and to the terminal C in the normal signal recording/reproducing mode. The head height control state in the recording/reproducing mode is shown by the imaginary line in FIG. 1 and in FIG. 3, respectively.

In this case, by setting the driving voltage Vc during the recording/reproducing mode higher than the driving voltage Vb during the seek mode, as shown in FIGS. The amount of displacement of the bimorph plate 8 in the mode is increased, and the height of the recording head is higher than that in the seek mode.
The head height during playback mode is controlled to be low. However, in both of these modes, the tip of the magnetic head chip 1 comes into contact with the medium MD at a head height that is equal to or lower than the surface SF of the magnetic recording medium MD. There is. When the medium MD is a hard disk, the magnetic head chip 1 is slightly elevated above the surface SF of the medium MD due to so-called dynamic pressure or the action of an air film accompanying the rotation of the medium MD. In this way, the contact pressure (or head load) of the magnetic head chip 1 against the surface SF of the magnetic recording medium MD in the seek mode is controlled to be lower than that in the recording/reproducing mode, and This prevents damage caused by head movement in the disk radial direction. This is because reliability of signal reproduction is not required during seek mode and during recording/playback mode, so a small head load is sufficient. This is taken into consideration.

By the way, the drive control method of the bimorph plate 8° for controlling the head height in the above-described embodiment is a so-called open-loop control, which detects the head load and the amount of displacement of the bimorph plate 8, and So-called closed loop control may be performed in which the head height is controlled according to the detection result.

FIG. 4 shows an example of a circuit configuration for such closed loop control. Here, the bimorph plate 8 in FIG. 4 is used for controlling the head height position, for example, like the bimorph plate 8 in the configuration shown in FIG. 1.

In FIG. 4, at least one of the electrodes on both sides of the bimorph plate 8 is divided into a drive electrode 8a and a displacement detection electrode 8b. A lead wire led out from the displacement detection electrode 8b is connected to, for example, a non-inverting input terminal of the differential amplifier 14. A reference voltage from a reference voltage supply circuit 15 is supplied to an inverting input terminal of the differential amplifier 14 . The reference voltage supply circuit 15 outputs, for example, three different reference voltages in response to the mode switching control signal. In other words, the start/stop mode of a medium such as a disk, the seek mode, and the signal recording/playback mode.
Output different reference voltages. The signal from the differential amplifier 14, the so-called control error signal, is passed through a low-pass filter (LP
F) 16 to a bimorph drive circuit 17, and the output from this bimorph drive circuit 17 is supplied to the drive electrode 8a of the bimorph plate 8, thereby forming a closed loop.

In this closed-loop head height position control, the head load or the displacement of the bimorph plate 8 is detected as a voltage signal by the displacement detection electrode 8b, and an error of the detected voltage with respect to the reference voltage from the reference voltage supply circuit 15 is detected. is taken out by the differential amplifier 14 and sent to the bimorph Fi8 via the LPF 16 and the bimorph drive circuit 17.
Drive control is performed so that the amount of displacement of the bimorph plate 8 corresponds to the reference voltage. This reference voltage is switched according to each of the operation modes described above, and when the configuration is similar to that shown in FIG. Each reference voltage may be set in advance so that the amount of displacement increases during the signal recording/reproducing mode.

If such closed-loop control is adopted, not only will it be possible to achieve the effects of the embodiments shown in FIGS. Even in such a case, a specified head height corresponding to each mode can be stably maintained, and a good head contact state can be obtained.

Next, FIG. 5 shows, as still another embodiment of the present invention, an example in which the magnetic head chip 1 is configured to be able to control displacement in the trunk width direction (direction of arrow C).

In FIG. 5, the magnetic head chip 1, parallel plate spring 3.4, and head mounting base 5 correspond to the respective parts 1.3.4.5 of the configuration shown in FIGS. 1 to 3, respectively. , the mounting hole 6, the notch 7, and the notch 9 are also connected to the first
This corresponds to each part 6.7.9 in FIGS. 3 to 3. Although not shown here, the proximal end of a bimorph plate 8 as shown in FIGS. This is to insert a guide. Further, the parallel leaf spring 3.4 shown in FIG. 5 is integrally formed with the connecting plate 21 on the head mounting base 5 and the mounting plate 22 of the bimorph plate 25 serving as the head support plate.
A magnetic head chip 1 is attached and fixed to the tip of a bimorph plate 30 for supporting the head. The bimorph board 25 is
The magnetic head chip 1 is inserted in the length direction of the gap of the magnetic head chip 1, that is, in the width direction of the recording track (direction of arrow C).
This system enables so-called tracking control by controlling the displacement of the head, and in addition to the control in the head height direction perpendicular to the recording surface of the medium (in the direction of arrow A) in the configuration shown in FIG. It is possible. Note that the rotational movement direction of the magnetic recording medium, such as a hard disk, is the direction of arrow B in the figure, as described above.

According to the embodiment shown in FIG. 5, the magnetic head chip 1 can be controlled in two axes with a simple configuration with a small number of parts. , the rigidity of the overlapped part is increased, and the parallel plate spring 3.4 does not cause track deviation, is jitterless, and has high response only in the head pressure direction.
The bimorph plate 25 allows tracking servo to be applied.

Note that the present invention is not limited to the above-mentioned embodiments; for example, as a configuration for controlling the head height,
The head pressing force downward (in the direction of media contact) is obtained by a parallel plate spring, and this pressing force is regulated by the displacement of the bimorph plate, but the downward head pressing force is generated only by the bimorph plate. In addition to the piezoelectric plate such as a bimorph plate, various electro-mechanical conversion elements can be used as the height control driving means.

Further, in the illustrated example, the head chip is directly supported by a head support plate, etc., but it goes without saying that the present invention can be easily applied to so-called hard disk slider structure heads, T-shaped heads, button-shaped heads, etc. be.

H0 Effects of the Invention According to the magnetic head device of the present invention, since the head contact pressure in the seek mode is suppressed to be lower than that in the signal recording/reproducing mode, when the head moves in the direction across the recording track, the required signal is To the extent that playback is possible, damage can be prevented from occurring, the durability and reliability of the head and media can be improved, and signal recording/playback characteristics and electrical and mechanical characteristics can be satisfied. be able to.

[Brief explanation of the drawing]

FIG. 1 is a front view schematically showing the main structure of an embodiment of the present invention, FIGS. 2 and 3 are schematic front views for explaining head height control, and FIG. 4 is a front view schematically showing the main configuration of an embodiment of the present invention. A block diagram showing an example of a circuit configuration for head height control used in another embodiment, and FIG. 5 is a perspective view schematically showing a main part of still another embodiment of the present invention. 1... Magnetic head chip 2... Head support plate 3.4... Parallel leaf spring 5... Head mounting base 8.25... Bimorph plate 11... Changeover switch 12.13...・Drive voltage source MD...Magnetic recording medium □ ゞMD Fig. 1 Seawamo Fff's △ - Shoulder 1 = Crowded Suzuda Fig. 2 Fig. 4

Claims (1)

[Claims] A magnetic head chip that magnetically records or reproduces signals while moving relative to a magnetic recording medium, and a height position of the magnetic head chip in a direction perpendicular to a recording surface of the magnetic recording medium. a height position control means for controlling, and switching control of the height position control means at least between a mode for recording or reproducing signals on the magnetic recording medium and a seek mode for searching recorded contents of the magnetic recording medium; 1. A magnetic head device comprising a switching circuit for controlling a contact pressure of a magnetic head chip against the magnetic recording medium in the seek mode to be lower than that in the recording/reproducing mode.