JPS59223928A - Rotary magnetic head device - Google Patents

Abstract

PURPOSE:To improve the recording and reproducing characteristics with an easy method by projecting a part of an arc-shaped surface of a magnetic head from the outside circumferential face of a rotary drum and allowing the position, where an air film is thinnest, and the position of the aperture part of a gap to coincide with each other and setting these positions in parallel with the center line of a core. CONSTITUTION:A part of the arc-shaped face of a magnetic head 10 is projected from the circumferential face of a rotary cylinder 3, and a center line C of this arc-shaped face and a gap line G passing a gap 8 of the magnetic head are parallel with each other, and the gap line G is behind the center line C in a direction opposite to the rotation direction of the cylinder, and this magnetic head 10 is so set onto the rotary cylinder 3 that this center line C and a diametral line D of the rotary cylinder coincide with each other. In this case, the gap 8 is formed in the position, which is shifted right from the center line C by a length (l), in parallel with the center line C. This length (l) is set to a value equal to the length between the point of the head outside circumference, where the gap line G is placed, and the point where the air film interposed between a tape and the arc-shaped face of the core is thinnest.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating head type magnetic recording/reproducing device, and particularly to a rotating magnetic head device.

FIG. 1 is a perspective view showing a rotary magnetic head Mffi portion of a conventional rotary two-head magnetic recording/reproducing device, and FIG. 2 is a plan view thereof. In both figures, the magnetic tape 1 is brought close by a guide post 2.5 to a rotary cylinder 3 equipped with a magnetic head 6.7 and rotating in the direction of the arrow, and a guide cylinder 4 that guides the running of the tape. Drive in direction B. At this time, the magnetic heads 6 and 7 each cover a half circle of the rotating cylinder 3 or more than half a circumference of the magnetic tape 1.
It is set to be in contact with The above magnetic head is
Conventionally, a magnetic head 6 has been attached to a rotating cylinder 3, as exemplified by a magnetic head 6 in FIG.

That is, the center a c it which bisects the circumferential angle of the arcuate surface of the magnetic head 6 coincides with the gear line G passing through the gap 8 of the magnetic head, and the coincident straight line passes through the center of rotation of the rotating cylinder. It was set to .

In this case, when the recording current shown in FIG. 11 is applied to the magnetic head 6 and the recorded data is reproduced, the envelope of the reproduction output of the magnetic head obtained should ideally be as shown in FIG. 5. , as shown in Figure 6, the level of the front and rear ends may be deteriorated, or as shown in Figure 7, the ideal level indicated by the broken line; I was able to obtain only a small level of output, which was a considerable loss of the ability I had. In FIGS. 4 to 7, 1°Eh and t respectively indicate a recording current, a novel, and a reproduction output level of 9 hours.

The causes of the above problems will be discussed below. First, if we look in detail at the state in which the magnetic tape 1 and the magnetic head 6 are in contact with each other, it is as shown in the rgB diagram. That is, the rotating cylinder 3 rotates in the direction of the arrow, and the magnet 9 and head 6 installed on the rotating cylinder rotate in the direction of the arrow together with the rotating cylinder. On the other hand, the 1M magnetic tape is traveling in the direction of arrow B at a speed that is safe (1/100 or less) compared to the circumferential speed of the rotating cylinder. This doki, the air is △, there is 'Iμm between the tube and the tape.
D1 This thin empty chain film 9 is formed. The thickness of this air film is not uniform on the arcuate surface of the head, and is smallest at the position M on the rear side, which is a minute amount (less than several 100 μm) in the opposite rotational direction from the position of the conventional gap IIIG. It has a distribution with values. That is, as shown in Fig. 9, which is a further enlargement of the area near the l\\rad arc-shaped surface in Fig. 8,
Air 1lII thickness H8 at the head outer circumference point S where the gap l1ilG is located Air IIIW thickness H at the head example circumference fIT at the position M which is a distance Q opposite to the rotational direction
T is smaller and is the smallest on the arcuate circumferential surface of the head. However, since even H6 is a minute amount of 1 Atm or less,
Conventionally, the difference between H3 and H-type was not a problem. However, as storage densities have increased, this difference has become a problem. That is, generally the level Eh of the reproduced signal is equal to the above air 1t! ! ! The evaluation formula ``spacing loss -54, 68, /λ (dB)'' is a guideline for indicating the amount of reduction in reproduction output. is the spacing [1 (gap between the magnetic tape and the magnetic head at the gap position), and λ is the wavelength of the signal. In the F formula, assume that λ-2μm and the difference between Hs and HT is about 0.1μ+!1.・But about 3 dB
This appears as a difference in degree, and this amount is a large value that cannot be ignored. In particular, the positions where the magnetic head 6 and the magnetic tape 1 start and end contact are closer to the edge of the width of the tape (and the contact force between the magnetic tape and the magnetic head decreases, so the position is closer to the edge of the width of the tape than the center in the width direction). The amount of spacing loss further increases, resulting in a reproduction output level as shown in FIG.

Therefore, if the gap position of the magnetic head 6 is arranged to match the lower position in FIG. 9, the spacing loss l will be minimized, and the reproduction output level will be in the ideal form as shown in FIG. 5- It will be possible.

In order to realize this, a method as shown in FIG. 10 can be considered. In other words, in order to simply change the opening position of the gap 8 on the arcuate surface, the angle θ formed with the diameter line of the rotating cylinder is tilted by the gap IG (in this case, it coincides with the center line C). The magnetic head 6 may be mounted on a rotating cylinder. However, this method! This would be a problem because the wear of the magnetic heads would cause the frontage position of the gap 8 on the arcuate surface to shift and deviate from the minimum spacing position, and the angular protrusion between the two heads would also be disturbed.

The object of the present invention is to improve the above-mentioned problems in the recording and reproducing characteristics of a rotating magnetic head, and to guarantee good image quality with a magnetic recording and reproducing I! An object of the present invention is to provide a rotary magnetic head device for ill.

The feature of this invention is that a part of the arc-shaped surface of the magnetic head protrudes from the outer circumferential surface of the rotating drum, and that the center line that bisects the circumferential angle of the arc-shaped surface corresponds to the rotation of the rotating cylinder. Install the magnetic tape so that it passes through the center, and also check the position where the air suction between the running magnetic tape and the partially protruding arcuate surface of the core is the thinnest, and the circle of the core. The gap was displaced from the center line of the core and set parallel to the center line so that the position of the opening of the gap on the circumferential surface coincided with the position of the gap opening.

The most preferred embodiment of the present invention will be explained below using FIGS. 11 and 12! F. That is, a part of the arcuate surface of the magnetic head protrudes from the circumferential surface of the rotating cylinder, and the center line C of the arcuate surface and the gap line G passing through the gap 8 of the magnetic head are parallel; The magnetic head 10 is made so as to be opposite to the direction of rotation and behind the center line C, and placed on the rotating cylinder 3 so that the center taC of the arcuate surface of the magnetic head and the diameter line of the rotating cylinder coincide. Just set it up. In this case, as shown in FIG. 11, the gap 8 is a distance of 1 from the center line C of the arc-shaped surface.
! It is formed to be parallel to the center line C at a position shifted to the right by tfl. This distance l1Iil is set equal to the distance 1a9 between point S and point 1 shown in FIG.

In the above description, one of the two magnetic heads 6 and 7 has been described, but the same applies to the other head 7. In addition, although the rotary two-head type magnetic recording and reproducing device has been described here,
The same work can be done with multiple heads such as 4 heads, 6 heads, or just 1 head. Further, in the above description, the case where the rotational direction of the cylinder and the running direction of the tape are the same direction is described, but the same applies to the case where the direction of rotation of the cylinder and the running direction of the tape are opposite.

According to the present invention, it is possible to improve the recording and reproducing characteristics of a rotary magnetic head device using a simple and inexpensive method, and thereby it is possible to provide a magnetic recording and reproducing device with good image quality.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional rotary magnetic head device. 2 is a plan view of the rotating magnetic head device of FIG. 1. FIG. FIG. 3 is a schematic diagram showing the installation of a conventional magnetic head. FIG. 4 is a recording current characteristic diagram. FIG. 5 is an ideal reproduction output characteristic diagram. FIG. 6 shows an example of conventional reproduction output characteristics. FIG. 7 shows another example of conventional reproduction output characteristics. FIG. 8 shows the distribution of gaps between the magnetic tape and the magnetic head. FIG. 9 is a partially enlarged view of FIG. 8. FIG. 10 shows an example designed to solve the problems of the prior art. FIG. 11 shows the most preferred embodiment of the invention. FIG. 12 shows the core of the magnetic head used in FIG. 11. In the figure, 1 is a magnetic tape, 3 is a rotating cylinder, 6.
7 is a magnetic head, 8 is a gap, 9 is an air film, and 10 is a core of the magnetic head. Note that in each figure, the same reference numerals indicate the same parts or the same contents. 10- Figure 1, Figure 2, Figure 11) 1 Denko Figure 12 Procedural Amendment (Voluntary) Commissioner of the Japan Patent Office 1, Indication of the case Patent Application No. 1981-08 2,
Title of the invention Rotating magnetic head device 3, Person making the amendment 5, Claims of the specification subject to amendment - and Detailed description of the invention column 6, Contents of the amendment (1) Correct accordingly. (2) [Slight amount (
A very small amount (less than several 100 μ-) is changed to a small amount (100 μ-
(a very small amount). (3) "It would be a problem." on page 6, line 12 of the specification is corrected to "It is a problem." (4) "Parallel" in lines 6, 12, and 19 of page 7 of the specification is corrected to "cough parallel." Above 2-2, Claims Consisting of a rotating cylinder that is equipped with a magnetic head consisting of a core and a coil and that rotates supported by a rotating shaft, and a guide cylinder that guides the running of the magnetic tape, on the outer circumferential surface of both cylinders. In a magnetic head device in which the magnetic tape is caused to run close to each other through a thin air film, the core has an arcuate surface and a gap opening in the arcuate surface, and the core has a part of the arcuate surface. The magnetic head is installed so that it protrudes from the outer peripheral surface of the rotary cylinder, and so that a center line dividing the circumferential angle of the arc-shaped surface into two equal parts passes through the center of rotation of the rotary cylinder, and the magnetic head is traveling. The point where the air film sandwiched between the magnetic tape and the partially protruding arcuate surface of the core is thinnest, and the position of the opening of the gap on the arcuate surface of the core are determined. A rotary magnetic head device characterized in that the gap is displaced from the center line of the core so as to coincide with each other, and is set parallel to the center line. 3-

Claims (1)

[Claims] Consisting of a rotating cylinder that is equipped with a magnetic head consisting of a core and a coil and rotates supported by a rotating shaft, and a guide cylinder that guides the running of the magnetic tape, the outer peripheral surfaces of both cylinders are provided with the magnetic head. In a magnetic head device in which a tape is caused to run in close proximity through a thin air film, the core has an arcuate surface and a gap opening in the arcuate surface, and a portion of the arcuate surface is caused by the rotation. The magnetic head is positioned llf so as to protrude from the outer peripheral surface of the cylinder and such that a center line dividing the circumferential angle of the arc-shaped surface into two equal parts passes through the center of rotation of the rotary cylinder, and The magnetic tape and the part that protrudes above? The gap is formed so that the position where the air film sandwiched between the arcuate surfaces of the core is thinnest coincides with the position of the opening of the gap that goes down to the arcuate surface of the core. A rotating magnetic head device characterized by being displaced from a center line and set parallel to the center line.