JPS60182042A - Rotary magnetic head drum - Google Patents

Abstract

PURPOSE:To prevent the wear of a magnetic head and damage to a tape at acceleration or deceleration by providing a recessed part where a negative pressure is generated during turning and sucking the wound tape to a rotary drum outer circumferential wall to the surrounding of outer circumference of a window for magnetic head projection so as to decrease the floating air gap. CONSTITUTION:In a drum comprising a rotary drum 1, a fixed lower drum 2, a tape 5, input/output guides 41, 42 and a magnetic head, a recessed part 12 is provided to the surrounding of a projected window 13 of the magnetic head 11 of the rotary drum 1. When the rotary drum 1 is driven, a relative air flow 11 is caused as shown in Fig. (a) and a negative pressure part 113 is caused. Furthermore, a pressure line 114 of a line 112 is a positive pressure part. Thus, the wound tape 5 is sucked onto the rotary drum 1 as shown in Fig. (b). The magnetic head 11 is placed to a position lower by several hundred microns than the outer circumference of the rotary drum 1 at the part causing the adsorption as shown in Fig. (c).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to the reduction of flying air gaps in a magnetic recording/reproducing apparatus (1) to a rotating magnetic head drum (2).

[Technical background of the invention and its problems]

Conventionally, a plurality of V-shaped grooves have been installed on the outer periphery of a rotating magnetic head drum to reduce the thickness of the air film generated between the drum and the tape wound during rotation to an optimum value that matches the equipment conditions. That is, the V-shaped groove is a major factor in setting the flying gap between the magnetic head and the tape during recording and reproduction.

Therefore, if the air film C2 generated between the rotating drum and the tape is guided and exhausted by the excess amount from the V-shaped groove (2), the outer circumference of the rotating drum C2 can be seen from C2 by an arbitrary amount of protrusion. An appropriate flying gap for the magnetic head and the wound tape is obtained.

Recently, the recording density of magnetic recording and reproducing devices has been increasing (as a result, the relative speed between the C1 rotating drum and the tape, V, has tended to increase. Therefore, the equipment conditions (2) to obtain an optimal flying air gap between the magnetic head and the tape that match (= indicates the direction in which the V-shaped groove also increases (it has to be binary.If it does not depend on the V-shaped groove, one way is to increase the tape tension, but due to the mechanical properties of the tape This is not at all desirable since it has its limitations and also requires powering up the device.

On the other hand, during the acceleration and deceleration period of the rotating drum, there is a period when the floating air gap between the magnetic head and tape disappears, and at this time, the surface pressure between the magnetic head and tape increases abnormally (2), causing wear of the magnetic head and damage to the tape. In order to prevent this, it is necessary to partially reduce the tape tension.

To summarize the above, as the density of magnetic recording and reproducing devices increases, the relative speed between the magnetic head and the tape also increases, but as the relative speed increases, the flying gap between the magnetic head and the tape also increases. Therefore, the V-shaped groove is increased to reduce the floating air gap, but during the acceleration and deceleration period of the rotating drum, an abnormal surface pressure increase between the magnetic head and the tape (due to wear of the magnetic head and damage to the tape) In order to prevent this, it is necessary to manipulate the tape tension.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a rotating drum that can secure an optimum floating gap without increasing the V-shaped groove on the outer periphery of the rotating drum or changing the tape tension operation C in high-speed, high-density recording and reproducing.

[Summary of the invention]

The present invention eliminates the V-shaped groove from the outer circumference of the rotating drum.

Instead, during one rotation, negative pressure is generated around the outer periphery of the magnetic head protrusion window, which is installed facing the outer periphery of the drum in order to obtain the optimum flying gap between the magnetic head and the tape. 5. [Effects of the Invention] According to the present invention, the magnetic head and tape that occur during the edge deceleration period of the rotating drum are The problems of magnetic head wear and tape damage when the floating air gap disappears can all be solved, and there is no need to intentionally manipulate tape tension during acceleration and deceleration periods. Of course, due to the generation of negative pressure by the concavity C2 of the one-rotation drum, the flying gap between the magnetic head and the tape during recording and reproduction is maintained at an optimum level according to the rotating drum speed of the device (- As described above, the present invention focuses on the fact that the negative pressure due to the depressions provided on the outer periphery of the rotating drum changes depending on the rotational speed, The wound tape is attracted to the recess by generating negative pressure, and a magnetic head is installed at the attraction point, so that the magnetic head and tape have an optimal flying gap that matches the device. It is intended to provide sliding contact, and even if high-speed recording and reproduction progresses further, it will be possible to cope with this by using negative pressure without relying on increasing the V-shaped groove or manipulating the tape tension.

[Embodiments of the invention]

FIGS. 1(a) and 1(b) are schematic diagrams of a rotating magnetic head drum showing an embodiment of the present invention. In the figure, 1 is a rotating drum, 2 is a fixed lower drum, 5 is a tape, and 4].

42 is an input/output guide, and 11 is a magnetic head. In the present invention, the drum 1 having such a structure (two-C two-rotating drum 1) is provided with a recess 12 around the protruding window 13 of the magnetic head 11.
A relative airflow 111 occurs as shown in a), and a negative pressure section 113 is generated. Note that 112 Fi is the approximate pressure line 114 positive pressure section. Therefore, the wound tape 5 is attracted to the drum 1 for one revolution as shown in FIG. 3(b). A magnetic head 11 shown in FIG. 3C is installed at a position several ff microns lower than the outer periphery of the rotating drum 1 at a location where attraction occurs. In this embodiment, a negative pressure generating recess 12 having the same shape as that shown in FIG. 4(a) is employed. 51 to 54 in FIG. 4(b) are the rotary drum 1. The rotation speed is 12m/sec.

It shows the approximate relationship between the degree of adsorption of the tape 5 when changing the speed to 30 m/sec, 4Qm/sec, and 60 m/sec. It is shown that the faster the rotation speed increases, the more the suction increases. Figs. 2(b) and 2(C) show other embodiments of the negative pressure generating recess 12. , rotating drum 1°
It is unique in that only part of the width (2) is provided.

Therefore, as described above (2) According to the present invention (2), the flying gap between the magnetic head and the tape during high-speed recording and reproducing can be reduced as the relative speed increases; It becomes possible to provide an extremely good rotating drum that prevents wear and damage to the tape.

Note that the present invention is not only applicable to a rotating magnetic head drum equipped with a fixed upper drum 3 as shown in FIGS. 1(C) and 2, but is not limited to the illustrated embodiment. It goes without saying that various button shapes and applications are possible without departing from the gist of the present invention.

Claims (1)

[Scope of Claims] A rotating device consisting of one or more stationary drums that are tilted while winding a tape at a predetermined angle, and a rotating drum that rotates with one or more magnetic heads mounted coaxially on the drums. A magnetic head drum (positioned at -. A rotating drum characterized by the fact that the area around the head protrusion window of the rotating drum is a "kupomi" that generates negative pressure to attract the tape to the outer wall of the rotating drum while the drum is rotating. magnetic head drum.