JPS5849935B2 - magnetic tape recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape recording device that is compact and capable of high-speed random access. In a magnetic recording device that electronically selects one or more of the magnetic heads for recording/reproduction, the magnetic tape is levitated with a uniform flying height relative to the head drum surface, and the magnetic head portion relates to a head drum structure that enables rotational scanning while maintaining a small and constant gap.

Conventionally, in this type of magnetic tape recording device, highly reliable scanning of the head drum against the magnetic tape has been an essential condition, and the method to achieve this is usually to use dynamic pressure generated by the rotation of the head drum surface. Two methods have been adopted: one is to levitate the magnetic tape from the head drum surface using an air film, and the other is to provide a large number of evenly distributed air supply holes on the head drum surface and utilize a static air film created by pressurized air supplied from the outside. ing.

The former method, which uses a hydrodynamic air film, has the advantage that the head rotor structure is simple and uniform tape floating can be achieved over a wide wrapping area, but the floating amount is essentially small at the outflow end. There are disadvantages in that it is difficult to achieve highly reliable non-contact scanning because there is a region where the pressure decreases, there is no pressure to support the tape when starting and stopping, and floating pressure is difficult to generate near the magnetic head. Ta.

On the other hand, the latter method of using a hydrostatic air film eliminates the above disadvantages and has the great advantage of being easy to realize non-contact scanning, but it requires air supply holes to be distributed discretely on the head drum surface. This structure allows the pressurized air to be engulfed in the central region of the magnetic tape, increasing the flying height of the central region of the magnetic tape compared to both edges and the inflow/outflow ends. This had the disadvantage that the flying height was uneven.

Further, as a cylindrical static pressure air bearing structure that uniformly supports a magnetic tape, a structure in which air supply holes are arranged in a rectangular shape along the boundary of the tape winding area is conventionally known.

However, when a head drum is used, the position of the entrance and exit of the tape winding area changes due to rotation, so even though air supply holes can be placed near both edges of the tape along the tape edge, the position of the entrance and exit of the tape winding area changes. It was not possible to apply this design concept to the inflow and outflow ends.

The present invention was made in order to solve the above-mentioned problems. Two air supply hole rows are provided along both edges of the tape on both sides of the outer peripheral surface of the drum head, and the pressurized air flowing out from the air supply holes is By providing a narrow groove that connects the two corresponding air supply holes to guide the air to the center of the head drum, the wide tape can be stably floated with a uniform flying height, and the magnetic head can be held high with a small and constant gap. The present invention provides a magnetic tape recording device that enables reliable rotational scanning.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic perspective view of a head drum used in a magnetic tape recording device according to the present invention.

In the figure, reference numeral 1 denotes a head drum, 2 a wide magnetic tape wound around the outer peripheral surface of the head drum 1 at an angle of 180 degrees or more, 5 and 6 tape guides for guiding the magnetic tape 2, and 7a , 7b are recording head stacks installed on the outer peripheral surface of the head drum 1 at axially symmetrical positions, that is, positions shifted by 180 degrees from each other, and 8a and 8b are installed close to the rear of these recording head stacks 8a and 8b. This is a playback head stack.

The recording head stack 7 a t 7 b and the reproducing head stacks 8 a and 8 b are composed of a large number of magnetic heads 12 arranged in parallel in the axial direction of the head drum 1.
Its surface is shaped like a cylindrical surface.

In addition, by providing head grooves 13 of appropriate width between these magnetic heads 12, adjacent magnetic heads 12 are separated from each other.

Further, on the outer circumferential surface of the head drum 1, a large number of narrow grooves 10 are arranged in parallel at appropriate intervals in the circumferential direction, extending long along the drum axis direction, and having both ends extending to the vicinity of both edges of the tape. At the same time, air supply holes 11a and 1lb are bored near both ends of each of these narrow grooves 10.

In such a configuration, during operation, the head drum 1 is driven in the direction of arrow A, that is, clockwise in the figure, by a motor (not shown), and pressurization is supplied into the rotating head drum 1 from a pressurized air source (not shown). Air flows out from the air supply holes 11a and 1lb and flows into the gap between the magnetic tape 2 and the head drum 1.

Each of the narrow grooves 10 has a width of, for example, lmrrt or less,
Further, the depth is set to be several times larger than the flying height of the magnetic tape 2.

Therefore, in the tape wrapping area, the air supply hole 11a
, IIb first fills the entire narrow groove 10 extending in the axial direction of the drum, and then fills the groove end 10 of each narrow groove 10.
a and 10b towards the tape edge.

In the tape winding area except near the tape entrance/exit, 2
Since there is no supply or outflow of pressurized air between the two air supply holes 11a and 1lb, a constant pressure is maintained at least over an area of the length of the narrow groove 10.

Therefore, uniform tape floating is achieved in this area.

On the other hand, in the vicinity of the tape entrance/exit, the pressurized air filled in each narrow groove 10 flows out from both ends 10a and 10b of the narrow groove 10 toward the tape edge, and flows from the entire narrow groove toward the widening gap of the tape entrance/exit. It also leaks out.

However, if the pitch of the narrow grooves 10 including the two air supply holes 11atllb is set sufficiently small, the air flowing out in the circumferential direction at the center of the head drum at the tape entrance/exit can be guided from several narrow grooves 10 near the tape entrance/exit. Can be supplemented with pressurized air.

At the tape entrance/exit portion, due to the flow in the circumferential direction, the air film pressure between the magnetic tape 2 and the head drum 1 is lower than in the tape winding center region.

However, while the radius of curvature of the magnetic tape 2 in the tape winding area is equal to the radius of the head drum 1, the radius of curvature of the magnetic tape in the widening gap area of the tape entrance and exit is close to infinity. Since the pressure exerted on the air film from 2 becomes considerably small, even if the air film pressure decreases considerably, the floating amount of the tape at the tape entrance/exit portion does not become smaller than that at the tape winding central region.

In this way, the magnetic tape 2 wound around the head drum 1 of the present invention is supported by an air film with a uniform flying height over the entire winding area, and the tape flying height does not decrease at the tape winding entrance/exit. do not have.

Next, regarding the gap in the magnetic head section, the recording/reproducing head stacks 7a, 7b, 8a, 8b mounted on the outer peripheral surface of the head drum 1 are pushed into the magnetic tape 2 by several tens to hundreds of μm. head drum 1
protrudes from the outer circumferential surface of the

Moreover, these head stacks 7a, 7b, 8a, 8b
Since the surface of the head drum 1 has a cylindrical surface with a smaller radius of curvature than the head drum 1, dynamic pressure is generated in the wedge-shaped gap between the head drum 1 and the magnetic tape 2, pushing the magnetic tape 1 towards the head i-ram. It floats from the outer peripheral surface of 1 with a minute gap.

The tape floating gap in the recording/reproducing gap section 9 of the magnetic head 12 is maintained at a minute and constant gap of submicrons by the head groove 13 of appropriate width and depth provided between adjacent magnetic heads 12. .

FIG. 2 is a schematic diagram of the magnetic tape recording apparatus of the present invention using the above-mentioned head drum.

In the figure, 3 is an unwinding reel, 4 is a take-up reel, and since the other components are the same as in FIG. 1, they are designated by the same reference numerals and their explanations will be omitted.

Record and playback head stack? a, 7b, 8a, Bb
each has several dozen magnetic heads 12 (see FIG. 1), and each magnetic head in the recording head stacks 7a and 7b and each magnetic head in the reproducing head stacks 8a>8b are arranged in a staggered manner. At least 100 tracks or more of data can be recorded on the wide magnetic tape 2.

Each magnetic head is selected by a head selection circuit mounted in a head rotor (not shown), and the head selection signal and recording/playback signals necessary for this are transmitted to the head drum via a rotary transformer (not shown). and the fixed side.

In this way, such a magnetic tape recording device has the characteristics of both the large capacity of a magnetic tape device and the high reliability and high-speed random access properties of a magnetic drum device. A file device can be realized.

As explained above, according to the magnetic tape recording device according to the present invention, a large number of narrow grooves are arranged in parallel in the circumferential direction on the outer circumferential surface of the head drum, and each groove Since minute air supply holes are provided near both ends of the narrow groove, a wide magnetic tape can be stably floated with a uniform flying height, and a large number of magnetic heads can be rotated reliably with a constant submicron gap. A head drum structure that can be scanned can be realized.

Therefore, in combination with the existing technology required for magnetic tape recording devices, it is possible to use magnetic tape media to provide random access files that are smaller, cheaper, and have higher performance than magnetic disk devices, and the effectiveness is extremely high. .

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the head drum used in the magnetic tape recording device of the present invention, and FIG. 2 is a schematic configuration diagram of the magnetic tape recording device using the head drum shown in FIG. be. 1... Head drum, 2... Magnetic tape, 3... Unwinding reel, 4... Winding reel, 5, 6...・Tape guide, 7a, 7b・
... Recording head stack, 8a, 8b...
・Reproducing head stack, 10... Thin groove, 11a
, 1lb... Air supply hole, 12... Magnetic head, 13... Head groove.

Claims (1)

[Claims] 1. A wide magnetic tape, a head drum that wraps the magnetic tape over a range of 180 degrees or more, and is equipped with a number of magnetic heads that rotate and scan the inner magnetic surface in the longitudinal direction of the tape. a tape guide for guiding and positioning on both sides of the head drum; an unwinding reel and a take-up reel for feeding and winding the magnetic tape;
In a magnetic tape recording device that is driven by a drive motor or the like, a large number of thin grooves are circularly formed on the outer circumferential surface of the head drum, the grooves being long in the drum axis direction and having both ends extending close to both ends of the magnetic tape. A magnetic tape recording device characterized in that air supply holes are arranged in parallel in the circumferential direction and near both ends of each of these narrow grooves.