JPH087854B2 - Magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording / reproducing apparatus including a rotary head assembly such as a video tape recorder and a digital video tape recorder. The present invention relates to an improvement of a head drive unit.

[Conventional technology]

FIG. 5 is a sectional view showing a main part of a conventional magnetic recording / reproducing apparatus, and FIG. 6 is a view taken along the line VI-VI in FIG.

In FIGS. 5 and 6, 1 is a fixed drum, 2 is a bearing mounted on the fixed drum 1, 3 is a rotating shaft supported by the bearing 2 and rotating, and 4 is fitted to one end of the rotating shaft 3. The mounted pedestal 5 is a rotary drum attached to the pedestal 4 with screws 6. 7 is a screw on the rotary drum 5
A magnetic head driving device mounted by using the above, 9 is a lower transformer mounted on the fixed drum 1, 10 is an upper transformer mounted on the pedestal 4, 11 is a wiring board mounted on the rotating drum 5, and 12 is It is a non-rotating contactor for supplying a control current to the magnetic head driving device 7.

Further, 13 is a rotating electrode provided on a part of the pedestal 4 so as to be in sliding contact with the contact 12, and 14 is a contact portion 15 from the electrode 13.
And a connecting portion that makes electrical contact with the magnetic head driving device 7 via the wiring board 11, 16 is a magnetic head attached to the magnetic head driving portion 7, and the connecting portion 17, the wiring board 11, and the connecting portion
It is electrically connected to the upper transformer 10 via 15. Reference numeral 18 denotes a recess provided in a part of the rotary drum 5 for accommodating the magnetic head drive device 7, and is formed larger than the magnetic head drive portion 7 so that the position of the magnetic head 16 can be adjusted. Reference numeral 19 is a position adjusting hole for adjusting the position of the magnetic head 16, and 20 is a magnetic tape which is in sliding contact with the magnetic head 16.

Further, FIGS. 7, 8 and 9 show the magnetic head driving device 7 in more detail.
Reference numeral 21 denotes a first yoke made of a magnetic material, 22 denotes a columnar first permanent magnet fixed to the first yoke 21, and 23 has a convex portion 23b on a part of the inner circumference. A second yoke made of a magnetic material is attached to the first yoke 21, and a third yoke 24 made of a magnetic material is attached to the second yoke 23.

Reference numeral 25 denotes a columnar second permanent magnet fixed to the third yoke 24 with the same magnetic poles as the first permanent magnet 22 facing each other, and 26 denotes the second permanent magnet 25 and the first permanent magnet. A pole piece made of a magnetic material, which is located between the two and fixed to either one.

Reference numeral 27 is a leaf spring made of a thin non-magnetic material, which is sandwiched between the first yoke 21 and the second yoke 23, and its extending portion 27a is formed on the first yoke 21 and the second yoke 23. It projects outward through the windows 21a and 23a provided, and the magnetic head 16 is attached to the tip thereof. Reference numeral 28 is a leaf spring made of a thin non-magnetic material, and is used for the second yoke 23.
It is sandwiched by the third yoke 24. 29 is a fixing member held by the leaf springs 27 and 28, and 30 is a position where the inner circumference has a gap between the first permanent magnet 22, the second permanent magnet 25 and the outer circumference of the pole piece 26. The bobbin 31 is fixed to the fixing member 29 with the adhesive 32 in FIG.
The coil is composed of an electric wire having a coating material wound around the second yoke 23 and has an annular gap G over the entire circumference with the convex portion 23b of the second yoke 23.

Next, the operation of the above configuration will be described with reference to FIG.

First, the first permanent magnet 22 causes the magnetic flux D due to the closed magnetic circuit formed by the pole piece 26, the second yoke 23, and the first yoke 21.
Occurs.

Similarly, the second permanent magnet 25 generates a magnetic flux E in the opposite direction to the magnetic flux D due to the closed magnetic circuit formed by the pole piece 26, the second yoke 23 and the third yoke 24.

Both the magnetic flux D and the magnetic flux E thus generated cross the annular gaps F and G in the same direction, and the total magnetic flux of the first permanent magnet 22 and the second permanent magnet 25 crosses the coil 31.

In this state, from the contact 12 to the electrode 13,
When a current is passed through 15 and 14, the coil 31, the bobbin 30, and the magnetic head 16 integrally move linearly in the vertical direction.

As a result, the magnetic head 16 is displaced in the width direction of the magnetic tape 20 and traces the magnetic recording trace with high accuracy.

FIG. 10 shows the hysteresis characteristic between the drive current and the displacement of the magnetic head driving device 7, and FIG. 11 shows the magnetic tape 20 on the magnetic tape 20 when recording is performed by the magnetic head driving section 7 having such a hysteresis characteristic. The recording track T is shown.

As is clear from FIGS. 10 and 11, when only adjusting the magnetic head drive unit 7 in the initial stage, the reference position of the magnetic head 16 changes due to the hysteresis characteristic as shown in FIG. Recording track T for recording
Overlap as indicated by d.

[Problems to be Solved by the Invention]

The conventional magnetic recording / reproducing apparatus is configured as described above, and since there is hysteresis between the drive current and the displacement, when performing recording after performing special reproduction or normal reproduction, the magnetic recording / reproduction is performed at a predetermined fixed location. Head does not move, 18
A step is created in the height between two magnetic heads facing each other by 0 °,
As a result, the recording tracks are overlapped with each other, and good recording tracks cannot be obtained, which causes a problem that image quality is deteriorated.

The present invention has been made to solve the above problems, and it is possible to adjust the height between head channels at the time of recording, obtain a good track, and improve the image quality. It is an object of the present invention to provide a magnetic recording / reproducing device that can be used.

[Means for solving problems]

A magnetic recording / reproducing apparatus according to the present invention is a hollow cylindrical first magnetic cylinder formed on the inner circumference of a cylindrical coil bobbin.
The yoke and the cylindrical coil bobbin are attached to the outer circumference of the cylindrical coil bobbin so as to face the cylindrical coil and form the same gap over the entire circumference, and are also magnetized in the radial direction and the outer circumference of the permanent magnet. A second yoke,
A magnetic head having a third yoke fixed to the second yoke and fixing the first yoke therein, and an optical sensor disposed inside the hollow cylindrical first yoke. A reflector is installed inside the cylindrical coil bobbin that moves with the leaf spring attached to the extension, and the light generated by the optical sensor is reflected by this reflector, and the position of the magnetic head is controlled by the detection information. It is characterized by being configured.

[Action]

According to the present invention, the position of the magnetic head is detected by the optical sensor, and the position of the magnetic head is controlled based on the detection information, so that the height when the magnetic head rushes into the magnetic tape is always constant, which is good. It is possible to obtain various recording tracks.

〔Example〕

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

FIG. 1 is a sectional view showing a magnetic head driving section of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is an operation of a drive system of the magnetic recording / reproducing apparatus of the magnetic recording / reproducing apparatus according to the embodiment of the present invention. 3 is a diagram for explaining the operation of the optical sensor of FIG. 1, and FIG. 4 is a diagram for explaining the operation of controlling the magnetic head by the optical sensor of FIG. is there.

In FIG. 1, reference numeral 33 is a hollow cylindrical first yoke formed of a magnetic material and formed on the inner peripheral portion of the cylindrical coil bobbin 30,
34 is a radially magnetized permanent magnet that is attached to the outer circumference of the cylindrical coil bobbin 30 so as to face the cylindrical coil 31 and form the same gap over the entire circumference, and 35 is fixed to the outer circumference of the permanent magnet 34. The second yoke 36 is fixed to the second yoke 35 and the third yoke 37 is fixed to the inside of the first yoke 33, and 37 is a hollow portion of the first yoke 33 and is attached to the third yoke 36. The fixed optical sensor 38 is a reflector that reflects the light generated by the optical sensor 37. The reflector 38 is arranged so as not to contact the first yoke 33 during operation, and is formed on the cylindrical coil bobbin 30.

As shown in FIG. 3, the optical sensor 37 includes a light emitting portion 37a that emits light and a light receiving portion 37b that receives light.
The light emitting portion 37a uses a light generating element such as an LED or a semiconductor laser, and the light receiving portion 37b includes a position detecting element.

It should be noted that in the above embodiment, the reflecting plate 38 is replaced by the cylindrical coil bobbin 30.
However, the reflector 38 may be provided on the leaf spring 27 to which the magnetic head 16 is attached by providing an extension on the extension.

 Next, the operation will be described.

In FIG. 2, a permanent magnet 34, which is a hollow cylinder and is magnetized in the radial direction, includes a first yoke 33, a second yoke 35,
The magnetic flux H is generated by the closed magnetic circuit formed by the third yoke 36 and the third yoke 36. The magnetic flux H traverses the annular gap I, and the subsequent operation is the same as in the conventional case.
When a current is passed from the electrode 13 through the electrodes 13 and the connection parts 15 and 14, the coil 3
1, 1, the bobbin 30, and the magnetic head 16 integrally move linearly in parallel vertically. And the magnetic head 16 is a magnetic tape
It is displaced in the width direction of 20, and traces the magnetic recording trace with high accuracy.

On the other hand, as shown in FIG. 3, when an electric current is applied to the coil 31, the cylindrical coil bobbin 30 is supported at its upper and lower ends by the leaf springs 27.
Moves in the J direction. This direction is aligned with the axial direction in which the drum rotates. The light emitted from the light emitting portion 37a of the optical sensor 37 is reflected by the reflecting plate 38 and enters the light receiving portion 37b, and the incident light is detected by the position detection element of the light receiving portion 37b.

The operation of controlling the magnetic head 16 by the optical sensor 37 will be described below with reference to FIG.

The voltage output of light detected by the position detection element of the light receiving portion 37b of the optical sensor 37 is amplified by the sensor amplifier 37c. Here, a certain reference height at which the magnetic head 16 is to be moved is H1, and the voltage obtained by the optical sensor 37 at that position is the specified voltage 40. For example, at the time of recording, the height at which the magnetic head 16 plunges into the magnetic tape 20 according to the standard is set as the reference height, and the voltage at that time is set as the specified voltage 40. Then, the specified voltage 40 and the optical sensor 37, that is, the voltage output from the sensor amplifier 37c are subtracted by the subtractor 37d, and the difference is taken. The magnetic head 16 is displaced. If the positional relationship between the magnetic head 16 and an external component such as a drum is measured in advance, the absolute position of the cylindrical coil bobbin 30 can be grasped.

As described above, in this embodiment, the position of the magnetic head 16 is detected by the optical sensor 37, the absolute position of the cylindrical coil bobbin 30 is grasped by the detection information, and the position of the magnetic head 16 is controlled. The height when the magnetic head rushes into the magnetic tape can be made constant at all times, and in each magnetic head driving device 7, it is possible to eliminate the step difference between the channels at the time of recording, and the step position with the Hif audio head. Relationships can also be maintained according to standards.

Further, by using the position information of the cylindrical coil bobbin 30 to form a closed-loop position servo, it is possible to electrically increase the rigidity against disturbance.

Further, an observer or the like is configured with respect to the magnetic head drive device, the speed of the coil bobbin is estimated from the drive current of the magnetic head drive device and the position information of the cylindrical coil bobbin, and the estimated speed is negatively fed back to perform electrical damping.

〔The invention's effect〕

As described above, according to the present invention, the hollow cylindrical first
A gap is formed by the magnetism of the yoke and the hollow cylinder magnetized in the radial direction.
The optical sensor is arranged inside the yoke of, and the reflecting plate is provided inside the cylindrical coil bobbin that moves together with the leaf spring with the magnetic head attached to the extending portion, and the light generated by the above-mentioned optical sensor is reflected by this reflecting plate, Since the position of the magnetic head is controlled by the detected information, the magnetic head can be moved to a fixed position to eliminate the step between the magnetic heads of each channel, and the step position with the Hifi audio head. The relationship can be maintained according to the standard, a good recording track can be obtained, and the image quality can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a magnetic head driving device of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is an operation of a drive system of the magnetic head driving device of the magnetic recording / reproducing apparatus according to the embodiment of the present invention. 3 is a diagram for explaining the operation of the optical sensor of the magnetic recording / reproducing apparatus according to one embodiment of the present invention, and FIG. 4 is a diagram for explaining the operation of the optical sensor of the magnetic recording / reproducing apparatus according to one embodiment of the present invention. FIG. 5 is a cross-sectional view showing the main part of a conventional magnetic recording / reproducing apparatus, FIG. 6 is a view for explaining the operation of controlling the head, FIG. 6 is a view taken along the line VI-VI in FIG.
FIG. 8 is an enlarged plan view of an essential part showing details of a conventional magnetic head driving device, FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7,
FIG. 9 is a side view of FIG. 8, FIG. 10 is a diagram showing a hysteresis characteristic between a magnetic head drive current and displacement of a conventional magnetic recording / reproducing apparatus, and FIG. 11 is a diagram showing recording by the conventional magnetic recording / reproducing apparatus. It is a figure showing the track when it went. 7 is a magnetic head driving device, 16 is a magnetic head, 27 is a leaf spring, 30 is a cylindrical coil bobbin, 33 is a first yoke, 34 is a permanent magnet, 35 is a second yoke, 36 is a third yoke, and 37 is An optical sensor, 37a is a light emitting unit, 37b is a light receiving unit, 37c is a sensor amplifier, 37d is a subtractor, 38 is a reflecting unit, 39 is a driver, and 40 is a specified voltage. The same reference numerals in the drawings indicate the same or corresponding parts.

Front page continuation (72) Inventor Eiji Yokoyama 1 Baba-Zou, Nagaokakyo-shi, Kyoto Inside Electronic Product Development Laboratory, Mitsubishi Electric Corporation (56) Reference JP-A-59-104722 (JP, A) JP-A-2- 230508 (JP, A)

Claims (1)

[Claims] 1. A cylindrical coil bobbin having a cylindrical coil fixed to the outer periphery thereof, a pair of leaf springs made of a non-magnetic material for supporting the cylindrical coil bobbin by a trampoline operation, and an extension of one of the pair of leaf springs. In a magnetic recording / reproducing apparatus equipped with a magnetic head attached to an existing portion, a magnetic head driving unit for driving the magnetic head is a hollow cylindrical first magnetic cylinder formed on the inner circumference of the cylindrical coil bobbin. The yoke is attached to the outer circumference of the cylindrical coil bobbin so as to face the cylindrical coil so as to form the same gap over the entire circumference, and is fixed to the outer circumference of the permanent magnet and the permanent magnet magnetized in the radial direction. A second yoke, a third yoke fixed to the second yoke, and a first yoke fixed to the inside of the third yoke, A light emitting surface and a light receiving portion of the light emitting portion, which has a reflecting portion formed inside the tubular coil and which operates on a trampoline integrally with a leaf spring having the magnetic head attached to the extending portion, and a light emitting portion and a light receiving portion. And a light sensor fixed to a third yoke inside the hollow of the first yoke so that the light receiving surface of the light source faces the reflection surface of the reflecting portion. The magnetic recording / reproducing apparatus is characterized in that the position of the cylindrical coil bobbin is detected by reflecting the light at the light receiving section and receiving the light by the light receiving section.