JPH0714264A - Rotary head-drum - Google Patents

Abstract

PURPOSE: To obtain a rotary head drum by which a phenomenon is prevented from occurring in which a tape is raised from the head drum and separated from the head on account of the air drawn into a face between the tape and the head drum by the rotation of the rotary drum. CONSTITUTION: A rotary head drum for a helical scanning recorder using a DAT medium is provided with plural grooves extending in the circumferential direction of the drum. The parameter of these grooves is such that the groove on the drum face is 100μm±10μm and that the pitch of the groove is 285μm±28.5μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head drum for a helical scan recorder, and more particularly to a rotary head drum for a helical scan recorder using a DAT medium.

[0002]

BACKGROUND OF THE INVENTION It is well known to utilize helical scanning techniques to store audio signals, computer data, and other information on magnetic tape. Thus, for example, I
It is known to store computer data using DAT (Digital Audio Tape) technology based on the DDS (Digital Data Storage) format defined in SO / IEC standard 10777: 1991E.

A data storage device using the DAT technology is
A rotating head drum with a head for writing / reading data to / from a magnetic tape and with rotation for controlling / adjusting the operation of the device by processing the written / read signals. It consists of a tape deck. The head drum rotates at high speed (typically 2000 rpm) as the tape is pulled across it along the helical path, thus allowing the head to scan along a slanted track extending across the tape. . The maximum rate at which data can be transferred to and from the tape is limited, in part, by the speed at which the head scans along the track. As the total data storage capacity of DAT tapes increases as technology improves, there is a corresponding need for higher data transfer rates.

[0004]

One way to meet this need is to increase the rotational speed of the head drum, and thus the speed of movement of the head across the tape. But,
Increasing the rotational speed (eg, up to 5700 rpm) tends to increase the degree to which air is drawn between the tape and the head drum. The air that is drawn acts to lift the tape and pull it away from the drum and the head that it is equipped with, which prevents writing and reading of data.

It is an object of the present invention to provide a rotary head drum that at least alleviates this problem. British Patent Specification No. 1425479, recording a magnetic tape comprising a rotatably mounted tape guide drum having at least one groove formed on the peripheral surface of the drum, and / or
Alternatively, a playback device is described. However, the purpose and sizing of this groove is specified to ensure that a layer of air is always formed between the tape and the drum. It is not disclosed how to handle excess air or how to prevent it.

[0006]

According to one aspect of the present invention, there is provided a rotary head drum for a helical scan recorder using a DAT medium, the drum comprising a circumferential direction of the drum. There are provided a plurality of grooves extending to, and the parameters of the grooves are as follows: grooves on the drum surface: 100 μm ± 10 μm groove pitch: 285 μm ± 28.5 μm Angle: 90 ° ± 10 ° Drum data to top groove: 9.95 mm ± 0.1 mm Typically, the drum is equipped with a total of six grooves. There is.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The drum described below is intended for use in a helical scan recorder incorporating DAT technology. Helical scan recorders in general, DA in particular
The design of the T-recording mechanism is well known to those skilled in the art and therefore will not be discussed here.

Referring to FIG. 1, a rotary head drum 1
0 is attached to the fixed lower drum 12 as shown. The rotating drum 10 has a low cylindrical shape with a diameter of 30 mm and a height of just over 4 mm.
Magnetic tape 16 in compliance with the Conference Standard
A number of holes 14 are provided at the lower edge thereof for receiving magnetic write and read heads for transferring data to and from the magnetic tape 16 (shown in phantom). The tape has a width of 3.81 mm, and is pulled by a recording mechanism along a path wound around a part of the circumference of the rotary drum 10.

The bottom surface (not shown) of stationary drum 12 forms a reference surface known as the "drum datum", which is referenced to the dimensions of the drum assembly. This bottom surface is fixed to a bracket (not shown) which is a part of the recording mechanism, and is 6 ° 2 with respect to the center line of the tape 16.
The 2 ′ rotary drum 10 is configured to be tilted. Thus, as the rotating drum 10 is rotated by the recording mechanism, the drum head in the hole 14 sweeps across the tape along a path inclined by this angle with respect to the tape centerline. The height of the rotating drum 10 above the drum datum is typically
7.29 mm, this dimension is
The head is selected to be flush with the centerline of the tape 16 when it is in an intermediate position along the portion of the tape wound on the drum 10. As is well known in the art, the lower portion of the drum 10 is only slightly tapered, reducing the likelihood of damaging the tape 16.

The peripheral surface of the drum 10 is smooth to reduce friction and wear of the tape 16 and incorporates six circumferentially extending grooves 18. The parameters of these grooves with respect to position and size are selected to control the air drawn between the tape 16 and the spinning drum 10. These parameters are identified by the reference symbols in FIG. 2 and are as follows: Groove width on drum surface: A 100 μm ± 10 μm Groove pitch: B 285 μm ± 28.5 μm Groove wall angle: α 90 ° ± 10 ° Drum Datum to Top Groove Distance: C 9.95 mm ± 0.1 mm Grooves 18 can be formed during machining used to finish the drum surface. This finish typically forms shallow recesses with a depth of 0.3 μm ± 0.15 μm and a width of 55 μm ± 5 μm on the peripheral surface.

[Brief description of drawings]

FIG. 1 is a side view of a drum.

FIG. 2 is a partially enlarged view of the periphery of a drum.

[Explanation of symbols]

 10 Rotary Drum 12 Fixed Drum 14 Hole 16 Tape 18 Groove A Groove Width on Drum Surface B Groove Pitch C Distance between Drum Datum and Top Groove α Angle of Groove Wall

Front page continued (72) Inventor Albert H Jeans United States California 94043 Mountain View, San Lucas Avenue 820 (72) Inventor Tadashi Nakai 2-2 Higashinaruse, Isehara City, Kanagawa Prefecture

Claims (4)

[Claims] 1. A drum having a plurality of grooves extending in the circumferential direction, wherein the parameters of the groove are: groove width on drum surface: 100 μm ± 10 μm groove pitch: 285 μm ± 28.5 μm Rotary head drum for helical scanning recorder using DAT media. 2. The rotary head according to claim 1, wherein the additional parameter of the groove is an angle formed by a wall surface of the groove: 90 ° ± 10 °.
drum. 3. The additional parameter of the groove is the distance between the upper part of the drum datum and the top groove: 9.95 mm.
The rotary head drum according to claim 1 or 2, wherein the rotary head drum has a diameter of ± 0.1 mm. 4. The rotary head drum according to claim 1, wherein the drum has six grooves.