JP2847764B2 - Apparatus for measuring electromagnetic conversion characteristics of magnetic tape - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic conversion characteristic measuring device for a magnetic tape, and more particularly, to a magnetic tape measuring device for accurately measuring an electromagnetic conversion characteristic without damaging a magnetic layer. The present invention relates to an electromagnetic conversion characteristic measuring device.

[Conventional technology]

In general, as a device for measuring electromagnetic conversion characteristics such as an output level and a noise level of a magnetic tape, the magnetic tape is wound around a rotating cylinder that rotates through an interlocking mechanism as appropriate.
A magnetic tape is used for recording and reproducing by bringing a magnetic head into sliding contact with the surface of the magnetic layer of the magnetic tape from the outside or inside of the rotary cylinder. (Problems to be Solved by the Invention) However, in these conventional electromagnetic conversion characteristic measuring devices, in each case, a magnetic coil wound around a cylinder is used. Since the same position on the surface of the magnetic layer of the tape is repeatedly slid in contact with the magnetic head throughout the measurement, the magnetic layer is easily damaged during the measurement, and the electromagnetic conversion characteristics cannot be measured accurately.

[Means for solving the problem]

The present invention has been made as a result of various studies in view of the current situation, and fine adjustment for finely moving the magnetic head in a direction parallel to the axis of the rotary cylinder is added to the magnetic head sliding mechanism of the conventional electromagnetic conversion characteristic measuring device. With a mechanism attached,
A rotation speed measuring device of the rotation cylinder is connected to the interlocking mechanism of the rotation cylinder, and each time the magnetic head slides on the surface of the magnetic layer of the magnetic tape a predetermined number of times, the magnetic head is finely adjusted in a direction parallel to the axis of the rotation cylinder. This allows the position of the magnetic head to slide in contact with the magnetic tape to be moved by the track width every predetermined number of times of sliding, so that the electromagnetic conversion characteristics such as the output level and noise level can be accurately determined without damaging the magnetic layer of the magnetic tape. It is one that can be measured.

〔Example〕

Hereinafter, an embodiment of an apparatus for measuring electromagnetic conversion characteristics of a magnetic tape according to the present invention will be described with reference to FIG.

FIG. 1 is a schematic explanatory view of an electromagnetic conversion characteristic measuring device for a magnetic tape according to the present invention, wherein 1 is a cylindrical rotary cylinder,
A slit 2 is provided in the peripheral wall, and a tape end holding portion 3 is provided on the inner peripheral surface of the peripheral wall end sandwiching the slit 2. Numeral 4 denotes a magnetic tape, both ends of which are fixedly held by the tape end holding portion 3 and wound around the peripheral surface of the rotary cylinder 1.

Numeral 5 is a magnetic head disposed so as to be in sliding contact with the surface of the magnetic layer of the magnetic tape 4 wound around the rotary cylinder 1.
It is mounted on a magnetic head fixing base 6 via a piezoelectric element 7 so as to be finely movable in a direction parallel to the axis of the rotary cylinder 1. The magnetic head fixing base 6 is fixed to a magnetic head supporting base 9 slidable left and right via a supporting member 8. Thus, the sliding state of the magnetic head 5 on the surface of the magnetic layer of the magnetic tape 4 is adjusted by the sliding of the magnetic head support 9, and the sliding position on the surface of the magnetic layer is adjusted to the track width by the operation of the piezoelectric element 7. Fine adjustment is made accordingly.

Reference numeral 10 denotes a motor for rotatingly driving the rotary cylinder 1 via a rotary shaft 11, which is connected to a rotary pulse counter 12 and further connected to a piezoelectric element 7 via a piezoelectric element drive circuit 13. Thus, the rotation cylinder 1
When the number of rotations of the rotating cylinder 1 is measured and reaches a predetermined number of rotations, the piezoelectric element 7 is actuated via the piezoelectric element driving circuit 13, and the magnetic head 5 moves slightly in the direction parallel to the axis of the rotary cylinder 1 in accordance with the track width. Adjusted.

14 is a changeover switch connected to the magnetic head 5,
The recording circuit 15 and the reproducing circuit 16 are switched and connected as needed.

[Action]

When measuring the electromagnetic conversion characteristics of the magnetic tape electromagnetic conversion characteristic measuring apparatus of the present invention thus configured, first, the magnetic tape is wound around the outer peripheral surface of the rotary cylinder 1 so that the magnetic layer is on the outside, Both ends are held and fixed to the tape end holding portion 3 of the rotary cylinder 1, and the sliding state of the magnetic head 5 on the surface of the magnetic layer of the magnetic tape 4 is adjusted by sliding the magnetic head support 9.

Thereafter, the motor 10 is driven to rotate the rotary cylinder 1 at a predetermined speed, and the changeover switch 14 connects the magnetic head 5 to the recording circuit 15 so that the magnetic head 5 slides on the surface of the magnetic layer of the magnetic tape 4. Then, magnetic recording is performed. After the end of the predetermined magnetic recording, the connection between the magnetic head 5 and the recording circuit 15 is switched to the connection between the magnetic head 5 and the reproducing circuit 16 by the changeover switch 14, and the electromagnetic conversion characteristics such as the output level and the noise level are changed. Is measured, and the operation is repeated.

In this way, the measurement operation of the electromagnetic conversion characteristics is repeatedly performed, and the rotation pulse counter 12 connected to the motor 10
When a predetermined number of rotations of the rotary cylinder 1 is measured, the piezoelectric element 7 is actuated, and the magnetic head 5 is finely adjusted in a direction parallel to the rotation axis of the rotary cylinder 1 so that the magnetic head 5 slides on the magnetic layer surface. The contact position is moved according to the track width. Then, the measurement operation of the same electromagnetic conversion characteristic is repeatedly performed on the adjacent track.

Thus, each time the magnetic head 5 slides on the surface of the magnetic layer of the magnetic tape 4 a predetermined number of times, the sliding position of the magnetic tape 4 is moved according to the track width, and the magnetic tape 4 repeatedly slides on the same position throughout. Therefore, the electromagnetic conversion characteristics such as the output level and the noise level can be accurately measured without damaging the magnetic tape 4 because the magnetic tapes 4 are sequentially moved to adjacent track positions.

The electromagnetic conversion characteristic measuring device of the magnetic tape of the present invention is configured as described above. Hereinafter, the electromagnetic conversion characteristic of the magnetic tape was measured using the magnetic tape electromagnetic conversion characteristic measuring device of the present invention shown in FIG. A test example will be described.

As the magnetic tape, Hitachi Maxell S-VHS video tape ST-120 was used.

In the apparatus for measuring the electromagnetic conversion characteristics of a magnetic tape shown in FIG. 1, an Al-Cu alloy cylinder having a diameter of 60 mm and a length of 10 mm has a surface roughness of 0.
1s or less, the roundness is processed to within 2 μm, and a 4 mm wide slit 2 and a tape end holding portion 3 are attached to the peripheral wall. Then, both ends of the video tape 4 are fixed by the tape end holding unit 3, and the magnetic head support 9 is slid and adjusted, and the magnetic head 5 fixed on the magnetic head fixing base 6 via the piezoelectric element 5 rotates. The contact pressure at the time of sliding contact with the magnetic layer surface of the video tape 4 wound around the cylinder 1 was adjusted.

Next, the motor 10 is driven to rotate the rotary cylinder 1 so that the relative speed between the magnetic head 5 and the video tape 4 becomes 5.6 m / sec.
And the recording circuit 15, and connect the magnetic head 5 to the video tape 4
The magnetic recording was performed at a recording frequency of 8 MHz by sliding on the surface of the magnetic layer. After the end of the predetermined magnetic recording, the connection between the magnetic head 5 and the recording circuit 15 was switched to the connection between the magnetic head 5 and the reproducing circuit 16 by the changeover switch 14, and the reproduced output was measured. By repeating this operation, the rotation number of the rotary cylinder 1 measured by the rotation pulse counter 12 becomes 1000
At this time, the piezoelectric element 7 is actuated to finely adjust the magnetic head 5 in the direction parallel to the rotation axis of the rotary cylinder 1 by 30 μm in accordance with the track width of the video tape 4, and on the adjacent track, as described above. Recording and reproduction were performed. The fine movement adjustment of the magnetic head 5 and the recording and reproduction on the adjacent track were repeated for 5 minutes, and the reproduction output was measured.

FIG. 2 is a graph showing the relationship between the reproduction output measured in this way and the measurement time as a test example.
As a conventional example, a graph is shown in which the reproduction output is measured under the same conditions with the magnetic head 5 slidably in contact with the same position on the video tape 4 without performing movement adjustment according to the track width of the video tape 4. .

As is apparent from these graphs, according to the conventional measurement method, the magnetic head slides on the same position of the magnetic tape from beginning to end, and as a result, the magnetic layer of the magnetic tape is damaged and the reproduction output appears as a temporal change. However, according to the electromagnetic conversion characteristic measuring apparatus for magnetic tape of the present invention, there is no change in the reproduction output with time. Therefore, according to the measuring apparatus of the present invention, the magnetic layer of the magnetic tape may be damaged. It can be seen that the reproduction output can be accurately measured without any problem.

〔The invention's effect〕

As described above, in the electromagnetic conversion characteristic measuring apparatus of the present invention, the magnetic head sliding mechanism is provided with the fine movement adjusting mechanism for finely moving the magnetic head in the direction parallel to the axis of the rotary cylinder, and the rotary cylinder When the magnetic head slides on the surface of the magnetic layer of the magnetic tape a predetermined number of times, the magnetic head is finely adjusted in a direction parallel to the axis of the rotary cylinder. The position of sliding contact with the surface of the magnetic layer of the tape can be moved according to the track width, and the characteristics of the electromagnetic conversion can be measured. Therefore, without damaging the magnetic layer of the magnetic tape, noise level, output level, etc. Can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the electromagnetic conversion characteristic measuring device for a magnetic tape of the present invention, and FIG. 2 is a diagram showing the relationship between the reproduction output measured by the electromagnetic conversion characteristic measuring device of the present invention and the measurement time. is there. 1 ... rotary cylinder, 4 ... magnetic tape, 5 ... magnetic head, 6 ... magnetic head fixing base, 7 ... piezoelectric element, 9 ...
... Magnetic head support, 10 ... Motor, 12 ... Rotary pulse counter, 15 ... Recording circuit, 16 ... Reproduction circuit

Claims (1)

(57) [Claims] 1. A rotary cylinder 1 driven to rotate by a motor 10.
And a magnetic head 5 slidably in contact with the surface of the magnetic layer of the magnetic tape 4 wound on the peripheral surface of the rotary cylinder 1. The magnetic head 5 measures the electromagnetic conversion characteristics of the magnetic tape 4. A magnetic head support 9 for supporting the head 5 is provided. The magnetic head support 9 is used to adjust the state of sliding of the magnetic head 5 on the surface of the magnetic layer of the magnetic tape 4 on the rotary cylinder 1. The magnetic head 5 is supported on the magnetic head support base 9 so as to be slidable in the direction of contacting and separating from the rotating cylinder 1.
A piezoelectric element 7 for finely moving in the direction parallel to the axis of the motor is mounted, and a rotational speed measuring device for measuring the rotational speed of the rotary cylinder 1 by the motor 10 is provided. By detecting that the rotation cylinder 1 has reached a predetermined rotation speed by the rotation speed measuring device, the piezoelectric element 7 is activated every time the magnetic head 5 slides on the surface of the magnetic layer of the magnetic tape 4 a predetermined number of times. An electromagnetic conversion characteristic measuring device for a magnetic tape, which is connected via a piezoelectric element drive circuit 13 so that a sliding position of the magnetic head 5 with respect to the magnetic tape 4 slightly moves according to a track width.