JPS601604A - Rotary head magnetic recorder - Google Patents

Abstract

PURPOSE:To improve the quality of the direct read-after-write signal with a simple and inexpensive structure by providing a circularly arcuate magnetic material of high permeability at the outer circumference of a rotary head rotor along the nonmagnetic side of a magnetic tape. CONSTITUTION:A circularly accurate magnetic material 11 of high permeability is provided at the outer circumference of a rotary head rotor 2 along the nonmagnetic side of a magnetic tape. At first, the tape 1 and the rotor 2 are driven and then a reproduction amplifier circuit 15 is actuated while the record signal is impressed from a record signal input terminal 13 via a record amplifier circuit 14. Thus the information is recorded on the tape 1 and at the same time the direct read-after-write signal is obtained at a reproduction signal output terminal 16. This signal has an extremely reduced level of cross feed noises and an extremely small time delay to the record signal. Thus the quality is improved for the direct read-after-write signal with a simple and inexpensive structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a rotary head magnetic recording device used in video tape recorders and the like, in which a recording and reproducing magnetic head is fixed to a rotating rotor.

[Prior art]

A conventional device of this kind, as typified by a 1-inch video tape recorder (hereinafter abbreviated as VTR) shown in FIG. The magnetic heads of the recording head 3 and the reproducing head 4, which are fixed to the rotor, are placed at positions as much as 120 degrees apart on the rotating rotor in order to avoid electromagnetic coupling. Therefore, the reproduction signal obtained by reproduction immediately after recording, that is, by direct read-after-write, has a significant delay compared to the recorded signal. For example, in the 3600 rpm single recording head rotary head shown in the figure, the reproduction signal during simultaneous reproduction during recording operation (hereinafter referred to as direct read-after-write) is approximately 5.5 ms shorter than the recording signal. This will cause a time delay. This approximately 5.5ms
This time is rarely a problem when a VTR is used mainly for camera input, such as in broadcasting. However, in computer graphics, where one image is created one after another on a computer and recorded on a VTR, there is a delay of approximately 5.5 ml per head scan in confirming that there are no errors. Become. ? :,in the case of,
Immediately after confirmation, the recording head has already traveled to the center of the data track, so recording cannot be started.
You have to wait one rotation. Therefore, two rotations are required to record one track, and it takes two hours to create a one-hour program.

These problems are due to the fact that it is difficult to bring the recording/playback image head close to the rotating rotor in order to prevent a type of crosstalk noise called crossfeed or feedthrough (hereinafter referred to as crossfeed noise). Therefore, an effective solution was desired. In the figure, 5 is a guide post, 6 is a fixed mandrel, 7 is a rotor motor, 8 is a capstan, and 9 is a capstan motor.

On the other hand, in the recording operation of a magnetic tape storage device for information processing, the recorded information is generated within 1 ma immediately after the information is recorded, the "no error - 1" confirmation is performed, and the next recording is started without waiting one revolution. Performing an action is a normal action.

This operation moves the recording head and playback head on the rotor for 10 minutes.
It is concentrated by bringing it close to each other. In this case, in order to reduce cross-feed noise caused by the magnetic flux of the recording head mixed into the rad core for reproduction, the
b) Side magnetic shielding material 10 made of ferrite etc.
Adopts a composite head with a high level of performance.

However, the use of composite heads of this type in rotary head recording devices has the drawback of making the device extremely expensive, and an inexpensive solution is desired.

[Object and structure of the invention]

The present invention was made in view of these circumstances, and its purpose is to provide a rotating head that can reduce cross-feed noise and improve direct read-after-write signal quality with a simple and inexpensive structure. An object of the present invention is to provide a magnetic recording device.

In order to achieve this objective, the present invention provides an arc-shaped high magnetic permeability material arranged around the outer periphery of a rotating rotor. Hereinafter, the present invention will be explained in detail using Examples.

〔Example〕

FIG. 2 is a structural diagram showing an embodiment of the present invention.

This embodiment is intended to ensure that the playback head 4 can operate not only when the recording head 3 is not recording, but also during its operation. This effect can be achieved by installing the arc-shaped high magnetic permeability material 11 in the area. That is, in this example, the arc-shaped high magnetic permeability material has a relative magnetic permeability of about 1000.
ferrite is used. Although the distance d between the inner periphery of the arc-shaped high magnetic permeability material and the running path of the magnetic head is exaggerated in the diagram, it is approximately 1/20th of the distance l between the recording head gap and the reproducing head gap. choose. The optimal distance l for obtaining the maximum effect can be found through experiments or electromagnetic analysis, but it is generally determined by taking into account the tape insertion mechanism into the magnetic tape running path, tape running guide mechanism, etc. stipulate. Further, 12 is a rotating transformer.

To operate this, first the magnetic tape 1 and the rotor motor 2 are each driven by a known method. Next, while applying a recording signal from the recording signal input terminal 13 via the recording amplifier circuit 14, the reproduction amplifier circuit 15 is operated. As a result, information is recorded on the magnetic tape, and a direct read/write signal with extremely low cross-feed noise and extremely low time delay relative to the recorded signal is obtained at the playback signal output terminal 16. It will be done. Therefore, by comparing the recorded data that has passed through the delay circuit 17 equal to the time delay of the direct read after write signal with the direct read after write data obtained from the terminal 16 in the comparison circuit 18) , it is possible to obtain at the terminal 19 whether the recorded data is correct or not. It is well known that the results of this determination can be used to supply various tape winding command signals necessary for each re-recording or new recording operation. That is, 20 is a capstan control circuit, and 21 is a cab drive circuit.

When the signals recorded in this way are to be reproduced exclusively later, the rotational phase of the rotor is adjusted to the running speed and rotation of the magnetic tape in a known manner so that the reproduction head 4 travels along the recorded data track. The effect of providing the skewer 11 on the reproduced signal output terminal 16 through control will be explained in comparison with the conventional example shown in FIG. In Figure 83, (a) shows the case of this example, and (b)
shows the case of a conventional example that does not have a circular arc-shaped high permeability material. First, the operation of the recording head 3 will be explained with reference to FIG. 3(a).A high-frequency recording current flows through the winding 22, generating magnetic flux shown by the arrow. According to electromagnetism, when a magnetic flux is absorbed into a high permeability material from air, which is approximately equal to free space, the magnetic flux is approximately perpendicular to its interface. That is,
Most of the leakage magnetic flux that does not contribute to the recording operation enters and leaves the inner periphery of the arc-shaped high magnetic permeability material 11, and is short-circuited by the high magnetic permeability material. Therefore, the magnetic field far from the recording head gap is extremely small compared to the conventional example shown in FIG. 3(b) without the arc-shaped high permeability material 11. This means that the recording head magnetic field near the reproducing head can be made extremely small. On the other hand, this circular arc-shaped high permeability material 11 is located at a distance d which is sufficiently large compared to the recording gap dimension, that is, the gap 2g between the recording rad gap and the magnetic surface of the magnetic tape, so that it cannot be used for the recording operation itself. No problem at all.

Next, to explain the operation of the reproducing head 4 shown in FIG. 3(a), a reproducing signal voltage is generated in the winding 23 due to the magnetic tape magnetic flux near the reproducing rad gap.

Here again, focusing on the magnetic field produced by the recording head 3, the leakage magnetic field during recording is weakened in the case of the circular arc-shaped high permeability material 11 due to the electromagnetic theory described above.

In other words, even if there is a leakage magnetic field, the magnetic flux is attracted toward the inner circumference of the circular arc-shaped high permeability material 11, so it is absorbed by the reproducing field 4 and interlinks with the winding 23. Magnetic flux is extremely low. Furthermore, since the arc-shaped high magnetic permeability material 11 is located sufficiently far away as in the case of the recording head, the reproducing operation itself has no effect on K. Therefore, the playback head winding 2
3, only the data signal on the magnetic tape near the read head gap is raised.

Note that arrow A indicates the rotation direction.

FIG. 4 shows another embodiment of the invention. The figure shows only the main parts around the rotating rotor.
b) is a partially sectional side view. This example is an example applied to a width scanning rotary head method, but in this method, recording and
When four magnetic heads are used for reproduction, the winding angle of the magnetic tape is approximately 90 degrees, so the arc-shaped high magnetic permeability material may also cover the outer periphery of the rotating head rotor 2 by approximately 90 degrees. . Therefore, in this embodiment, by embedding a ferrite material in the inner peripheral surface of the movable concave guide 24 for supporting the magnetic tape in a saddle shape, the movable circular arc-shaped high magnetic permeability material 1
1 is formed. In this case, since the movable concave guide 24 is made of metal (conductor), such a guide 2
4, the noise suppression effect is several dB higher than in the case of not having it. This is because magnetic flux cannot pass through the conductors on both sides of the arc-shaped high-permeability material 110, so most of the leakage magnetic flux is concentrated in the arc-shaped high-permeability material, and the magnetic flux is short-circuited. By not reaching the other head.

In this example, the recording frequency is 6.5 MHz, the distance between the head gaps is 11 m, the distance d between the circular arc-shaped high magnetic permeability material and the head is 0.51 m, and the cross-sectional area of the circular arc-shaped high magnetic permeability material 11 is In 2X3im2, the playback signal delay time is 290
The cross-feed noise was kept at μS, and the cross-feed noise was improved by -28 dB compared to the case without the arc-shaped high permeability tti1.

It should be noted that the structure in which the arc-shaped high magnetic permeability material 11 is provided with the arc-shaped conductor in close contact with surfaces other than its inner and outer peripheral surfaces, that is, both side surfaces in this embodiment, is as shown in FIG. Needless to say, the invention can also be applied to the diagonal scanning rotary head mechanism shown in FIG.

Furthermore, the movable concave guide 24 is rotatable around the shaft 24a in the direction of arrow B. In this regard, although the embodiment shown in FIG. 2 has not been described, it is possible to provide some kind of movable mechanism for rotating the arc-shaped high-permeability material 11 and separating it from the rotor. For those who design such things, it is easy to draw an analogy.

〔Effect of the invention〕

As explained above, according to the present invention, by providing the arc-shaped high magnetic permeability material along the outer periphery of the rotating rotor and the non-magnetic surface of the magnetic tape, playback is possible even when the recording head is in operation. Since the recording and reproducing heads can be installed close to each other without impairing the conditions for the heads to operate satisfactorily, there is an advantage that direct read-after-write can be performed at high speed. In addition, in the rotary head recording device according to the present invention, as is clear from the operating principle of the arc-shaped high-permeability material, not only cross-feed noise but also drive motor magnetic field, power transformer magnetic field, electromagnetic field of high-power broadcasting facility, etc. This has the advantage that it can also reduce general external noise.

Therefore, when the present invention is applied to a VTR,
By being able to install the recording and playback heads in close proximity, it not only has the advantage of being able to confirm the signal quality of recorded images reliably and quickly, but also eliminates interference caused by external radio waves near high-power transmitting stations. There are advantages.

In addition, when the present invention is applied to a file storage device for information processing, the recording head and the playback head can each have the same function as shown in FIG. There is an advantage that a simple and inexpensive head as shown in FIG. 3 can be used instead of the complicated and expensive head as shown in FIG. 3(b).

Furthermore, an inexpensive, large-capacity rough aisle device for OA is essential for an information processing device for office automation (hereinafter referred to as OA), and this is configured with a magnetic tape recording device having a rotary head recording mechanism to which the present invention is applied. This has the following advantages.

First, as with file storage devices for information processing, even if a magnetic head with a simple structure as shown in FIG.
Footer write operation is possible. There is no need to use a complicated and expensive magnetic head as shown in FIG. 1(b). second .

Furthermore, since a high-speed confirmation operation is always possible, even if an error occurs during recording, a re-recording operation can be performed immediately, and high-density recording with a relatively low error rate can be used. As a result, the cost per pit can be reduced. Third, the rotary head recording mechanism according to the present invention eliminates not only cross-feed noise but also drive motor magnetic field and
Since it is possible to reduce general external noise such as the magnetic field of a power transformer and the electromagnetic field of a high-power broadcasting facility, the high noise resistance required for an OA file device can be obtained.

[Brief explanation of the drawing]

FIG. 1(a) is a structural diagram of a conventional rotary head magnetic recording device for a VTR, FIG. 1(b) is a partially cutaway perspective view showing a conventional rotary head chip for information processing, and FIG. A structural diagram showing one embodiment, FIGS. 3(a) and 3(b) are diagrams for explaining the effects of the present invention in comparison with a conventional example, and FIG. 4(&) is another embodiment of the present invention. A plan view showing the same figure (b)
is a partial side view. 1... Magnetic tape, 2... Rotating head rotor,
3... Recording head, 4... Playback spatula F'', 8
” @ Fist/capstan, 9 pots φ... Capstan motor, 11-=... Arc-shaped high permeability material, 24...
Movable concave guide (circular conductor). Patent applicant Masaki Yamakawa, agent of Nippon Telegraph and Telephone Public Corporation

Claims (2)

[Claims] (1) A magnetic tape running means, a rotating rotor that rotates in contact with or floating on the magnetic tape, and a recording magnet that is fixed to the rotating rotor and performs recording while contacting or floating on the magnetic surface of the magnetic tape. In a rotary head magnetic recording device comprising a head and a reproducing magnetic head fixed to a rotating rotor and in contact with or floating on a magnetic surface of a magnetic tape, the magnetic surface is located along the scanning trajectory of the recording and reproducing magnetic head. 1. A rotary head magnetic recording device characterized in that a circular arc-shaped high permeability material is provided on a non-magnetic surface of a magnetic tape scanned by the magnetic head. (2) The rotary head magnetic recording device according to claim 1, wherein the arcuate high magnetic permeability material is provided with an arcuate conductor in close contact with the side surface.