JP2003346301A - Drawn-in amount of tape measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawn-in amount of tape measuring device that allows evaluation of the contact condition of a magnetic tape with respect to a magnetic head. <P>SOLUTION: In a helical-scan magnetic tape drive, having the magnetic head 808 mounted in an aperture 820 formed in the concave on the peripheral surface of a rotating cylinder 807, this device is a drawn-in amount of tape measuring device for measuring the drawn-in amount of the magnetic tape 817 resulting from being drawn in gaps A and B formed between the magnetic head 808 and side walls of the aperture 820. Further, the device comprises a laser-irradiating means 1a to have laser irradiated on the surface of the magnetic tape 817, a laser light receiving means 1b to receive the laser reflected from the surface, and a drawn-in amount of tape calculation section to calculate the drawn-in amount of the magnetic tape 817 drawn in the gaps A and B from the displacement of focus points of the laser received by the laser light receiving means 1b. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retracted amount measuring apparatus capable of evaluating a contact state of a magnetic tape with a magnetic head in a helical scan type magnetic tape drive.

[0002]

2. Description of the Related Art A helical scan type magnetic tape drive is, for example, a VHS type video tape recorder (V
DAT (digital audio) used for computer data backup, including TR)
(Tape) drive device.

This type of helical scan type magnetic tape drive is provided with a rotating cylinder which rotates obliquely in contact with the magnetic tape, and a pair of magnetic heads are disposed at the counter electrode position on the peripheral surface thereof. Has been. The pair of magnetic heads alternately and obliquely cross in the width direction of the magnetic tape, whereby information is recorded on and reproduced from the magnetic tape.

A helical scan type magnetic tape drive used in a VTR or the like has a rotating cylinder coaxially with a fixed cylinder, and records and reproduces signals on the magnetic tape using a magnetic head provided on the surface of the rotating cylinder. ing.

FIG. 5 shows a general configuration of a helical scan type magnetic tape drive. The helical scan type magnetic tape drive has a supply reel 801,
A take-up reel 802, a fixed guide 803 provided for restricting the travel of the magnetic tape, a guide 804 for controlling the tape tension, and a guide roller 8 arranged in pairs on the left and right.
05, an inclination guide 806, a rotating cylinder 807 that restricts the magnetic tape 817 to be stably wound without twisting, and a magnetic head 808 that is attached to the rotating cylinder 807 and records and reproduces signals on the magnetic tape 817, The magnetic tape 817 is pressed toward the take-up reel 802 by being pressed against the lead groove 809 provided on the side surface of the rotating cylinder 807 for traveling along the magnetic tape 817, the all erasing head 810, the cue head 811 and the capstan 812. A pinch roller 813, a guide roller 805, and an inclination guide 80 that play a role of feeding at a speed.
6 or the like is fixed to a movable portion 814, a guide groove 815,
A tape counter 816 or the like interlocked with the supply reel 801 or the take-up reel 802 is included.

FIG. 6 shows a magnetic head 8 during recording / reproduction.
An enlarged view of the vicinity of 08 is shown. The magnetic head 808 is attached to a window 820 formed in a concave shape on the peripheral surface of the rotating cylinder 807, and slightly (about approximately) than the surface of the rotating cylinder 807 in order to maintain good contact with the magnetic tape 817. 20 to 30 μm) are provided so as to protrude. Also,
Since the width of the magnetic head 808 is smaller than the width of the window 820, gaps A and B are formed between the magnetic head 808 and the side wall of the window 820. The magnetic head 808 rotates in the direction of the arrow in the drawing while being in contact with the magnetic tape 817.

[0007]

By the way, when the magnetic tape 817 runs, it is known that the magnetic tape 817 is drawn into the gaps A and B due to the tension and dynamic pressure of the magnetic tape 817. ing.

When the magnetic tape 817 is drawn into the gaps A and B, the friction between the magnetic tape 817 and the rotary cylinder 807 increases in the gaps A and B. Therefore, the magnetic tape 817 is generated by the friction between the magnetic tape 817 and the rotary cylinder 807. The wear powder adheres to the surface of the magnetic head 808 and causes noise during recording and reproduction.

However, conventionally, since there is no measuring device, it has been impossible to measure the amount of magnetic tape 817 drawn into the gaps A and B (the amount drawn). That is, the contact state of the magnetic tape with the magnetic head could not be evaluated.

Here, there is a technical problem to be solved by the present invention, and the present invention has an object to provide a retracted amount measuring apparatus capable of evaluating the contact state of the magnetic tape with the magnetic head. And

[0011]

In order to solve the above-mentioned problems, the present invention is configured as follows. According to a first aspect of the present invention, there is provided a helical scan type magnetic tape drive in which a magnetic head is installed in a window formed in a concave shape on a peripheral surface of a rotating cylinder, wherein the magnetic tape is drawn into a gap between the magnetic head and the side wall of the window. An apparatus for measuring a drawn amount of a magnetic tape for measuring an amount to be measured, a laser irradiation means for irradiating a laser to a surface of the magnetic tape, a laser receiving means for receiving a laser reflected from the surface, A magnetic tape is drawn, comprising: a drawn amount calculating unit that calculates an amount by which the magnetic tape is drawn into the gap from a displacement of a laser convergence point received by a laser receiving means. It is a quantity measuring device.

According to the first invention, it is possible to quantitatively know the amount of the magnetic tape drawn into the gap.

Thus, the product of the magnetic tape can be developed in consideration of the contact state with the magnetic head, so that the magnetic tape having an improved S / N ratio at the time of recording / reproducing can be developed.

The second aspect of the invention is such that the laser irradiation means and the laser light receiving means are configured to scan in the width direction of the rotary cylinder. It is a quantity measuring device.

According to the second invention, by scanning the laser displacement meter in the width direction of the rotary cylinder, not only the amount of the magnetic tape drawn into the gap of the rotary cylinder,
It became possible to quantitatively evaluate the displacement of the magnetic tape in the width direction of the rotating cylinder.

This makes it possible to develop a magnetic tape product in consideration of the contact state with the magnetic head, so that it is possible to develop a magnetic tape having an improved S / N ratio during recording and reproduction.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings as appropriate. FIG. 1 is a schematic diagram showing a first embodiment of a retracted amount measuring apparatus of the present invention. still,
1, parts similar to those in FIG. 6 are denoted by the same reference numerals, and description thereof is omitted.

Intake amount measuring apparatus 1 of the first embodiment
Corresponds to the invention described in claim 1. The drawn amount measuring apparatus 1 includes a light source 1a for irradiating the measurement laser beam 2a and a light receiving unit 1b for receiving the reflected laser beam 2b reflected on the surface of the magnetic tape 817 and measuring the displacement of the magnetic tape 817. Consists of.

As shown in FIG. 1, the measurement laser beam 2a irradiated from the light source 1a is reflected by a magnetic tape 817 wound around a rotary cylinder 807, and becomes a reflected laser beam 2b to the light receiving portion 1b. Finally, the amount of drawing into the gaps A and B of the magnetic tape 817 is measured by a drawing amount calculation unit (not shown) from the position change of the convergence point of the reflected laser beam 2b.

Here, it is preferable to use a laser displacement meter that can measure the displacement of the magnetic tape 817 in a non-contact manner as the pulled-in amount measuring device 1. The laser displacement meter receives a reflected laser beam from a laser beam spot formed on the surface of the measurement object when the laser beam irradiation unit irradiates the laser beam narrowly focused on the measurement object, and reflects the reflected laser beam. The displacement of the measurement object is evaluated based on the triangulation method from the displacement amount of the convergence point.
As the laser displacement meter used here, a known one can be used as long as the spot diameter is sufficiently small.
For example, “KL625 optical micro” manufactured by Anritsu Corporation can be used.

The amount of the magnetic tape 817 drawn is different between the two gaps A and B, and the rotating cylinder 807
The gap A at the front in the rotational direction of the rotary cylinder 8
Magnetic tape 8 rather than the gap B in the rearward direction of 07
It became clear that the amount of 17 was drawn large. Although the cause is not certain, in the gap A, the traveling magnetic tape 817 collides with the magnetic head 808 protruding from the surface of the rotating cylinder 807, so that the amount of bending of the magnetic tape 817 increases. It is guessed.

Thus, according to the retracted amount measuring apparatus 1 of the present invention, the retracted amount with respect to the gaps A and B of the magnetic tape 817 in the vicinity of the magnetic head 808 can be measured. If the measurement results obtained in this way are used for product development, the product development of the magnetic tape 817 can be performed in consideration of the contact state with the magnetic head 808, so the S / N ratio during recording and reproduction is improved. The developed magnetic tape 817 can be developed.

FIG. 2 shows a retracted amount measuring apparatus 1 according to the present invention.
It is a schematic diagram which shows 2nd Embodiment of this. In the second embodiment, the retracted amount measuring device 1 measures the retracted amount with respect to the gaps A and B of the magnetic tape 817 while scanning in the width direction of the rotating cylinder 807, and corresponds to the second invention. To do.

Here, the scanning with respect to the width direction of the rotary cylinder 807 of the retracted amount measuring device 1 is performed by the rotary cylinder 8.
This is performed by moving up and down the amount measuring device 1 in a predetermined step (width) with the rotation of 07. here,
As the pulled-in amount measuring device 1, it is preferable to use a laser displacement meter as in the first embodiment.

As a result, not only the amount of the magnetic tape 817 drawn into the gaps A and B of the rotary cylinder 807 but also the displacement of the magnetic tape 817 in the width direction of the rotary cylinder 807 can be clarified. Also,
By converting the variation data of the magnetic tape 817 into a three-dimensional stereoscopic image, the state of displacement of the magnetic tape 817 near the magnetic head 808 can be captured more intuitively.

Thus, according to the retracted amount measuring apparatus 1 of the present invention, the retracted amount with respect to the gaps A and B of the magnetic tape 817 in the vicinity of the magnetic head 808 and the displacement in the width direction of the rotating cylinder 807 are measured. Can do. By applying the present invention to product development, the magnetic tape 81 is considered in consideration of the contact state with the magnetic head 808.
7 product development can be performed, S during recording and playback
It becomes possible to develop a magnetic tape 817 with an improved / N ratio.

The embodiment of the present invention has been described above.
The present invention is not limited to this embodiment, and various modifications that embody the technical idea of the present invention are possible.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The results of measuring the amount of magnetic tape drawn obtained by the drawn amount measuring apparatus 1 of the present invention are shown. In this experiment, an 8.5 μm thick polyethylene terephthalate tape was used as the magnetic tape 817, the running speed of the magnetic tape 817 was 3.385 cm / s, and the rotating cylinder 807 was 10.2 m relative to the magnetic tape 817.
Rotating at a speed of / s. The diameter of the rotating cylinder is 21.7 mm, and the width of the magnetic tape 817 is 6.3.
5 mm, and the tension of the magnetic tape is 0.06 ± 0.01.
N. Further, the laser displacement meter used for the pulled-in amount measuring apparatus 1 is an optical micro KL625CH manufactured by Anritsu Corporation.

The laser displacement meter is installed at a position 1.6 mm from the surface of the rotary cylinder 807, and the magnetic tape is run while rotating the magnetic tape 817 while irradiating a fixed point on the rotary cylinder 807 with a laser beam. The cylinder 807 was rotated and the amount of the magnetic tape 817 drawn into the gaps A and B was measured.

The results are shown in FIGS. In FIG. 3, the vertical axis indicates the amount (μm) of the magnetic tape 817 drawn into the gaps A and B, and a positive value indicates that the magnetic tape 817 is not drawn into the gaps A and B.
A negative value indicates that the magnetic tape 817 is drawn into the gaps A and B. The horizontal axis indicates the time (ms) from the start of measurement, and is an amount corresponding to the distance between the laser irradiation site of the laser displacement meter and the magnetic head 808. 4A shows the state of measurement at about 0.8 ms in FIG. 3, and FIG. 4B shows about 0. 0 in FIG.
FIG. 4C shows a state of measurement at 9 ms, and FIG. 4C shows a state of measurement at about 1 ms in FIG.

According to FIG. 3, the magnetic tape is approximately 0.8 m.
It can be seen that it is drawn into the gap A by about 5 μm at s. According to FIG. 4 (a), the retracted amount measuring device 1
The more irradiated laser beam is incident on the magnetic tape 817 existing in the gap A. From the measurement result, it can be seen that the magnetic tape 817 is drawn into the gap A.

Thereafter, as the rotating cylinder 807 rotates, the magnetic tape 817 is moved to approximately 1 at approximately 0.9 ms.
It can be seen that the surface protrudes beyond the surface of the 7 μm rotation cylinder 807 (not drawn). According to FIG. 4B, the laser beam that is drawn and irradiated from the amount measuring device 1 is a magnetic tape 817 existing on the magnetic head 808.
Is incident. From the measurement results, the magnetic tape 817 is
It can be seen that the magnetic head 808 is lifted up.

Thereafter, as the rotary cylinder 807 rotates, the magnetic tape 817 is moved to about 3 at about 1 ms.
It can be seen that μm is drawn into the gap B. FIG.
According to (c), the laser beam drawn and irradiated from the amount measuring device 1 is magnetic tape 817 existing in the gap B.
Is incident. From the measurement results, the magnetic tape 817 is
It can be seen that it is drawn into the gap B.

As described above, by using the pull-in amount measuring apparatus 1 of the present invention, it becomes possible to quantitatively know the pull-in amount of the magnetic tape with respect to the gaps A and B. Further, by using the retracted amount measuring device of the present invention, it has become clear for the first time that the retracted amount of the magnetic tape in the gap in the forward direction of the rotating cylinder is larger than the gap in the forward direction of the rotating cylinder. .

[0035]

The present invention has the following remarkable effects. By using the pulled-in amount measuring device of the present invention, it is possible to quantitatively know the pulled-in amount into the gap of the magnetic tape. By applying the present invention to product development, magnetic tape products can be developed in consideration of the contact state with the magnetic head, so that magnetic tapes with improved S / N ratio during recording and reproduction can be developed. It becomes.

By using the retracted amount measuring apparatus of the present invention, it is possible to quantitatively evaluate not only the retracted amount of the magnetic tape with respect to the gap of the rotating cylinder but also the displacement of the magnetic tape in the width direction of the rotating cylinder. It became. Thereby, the product development of the magnetic tape can be performed in consideration of the contact state with the magnetic head, so that the magnetic tape having an improved S / N ratio at the time of recording and reproduction can be developed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a first embodiment of a retracted amount measuring apparatus of the present invention.

FIG. 2 is a schematic view showing a second embodiment of the drawn-in amount measuring apparatus of the present invention.

FIG. 3 is a graph showing a contact state of a magnetic tape to a magnetic head.

4A and 4B are schematic views showing a contact state between a magnetic tape and a magnetic head. FIG. 4A is about 0.8 ms, and FIG.
9 ms is shown, and (c) is about 1 ms.

FIG. 5 is a diagram showing a general configuration of a helical scan type magnetic tape drive.

FIG. 6 is an enlarged view of the vicinity of the magnetic head during recording and reproduction.

[Explanation of symbols]

1 Pull-in amount measuring device 1a Light source 1b Light receiver 2a Laser beam for measurement 2b Reflected laser beam

Claims (1)

[Claims] 1. In a helical scan type magnetic tape drive in which a magnetic head is installed in a window formed in a concave shape on the peripheral surface of a rotary cylinder, the magnetic tape is drawn into a gap between the magnetic head and the side wall of the window. An apparatus for measuring the amount of magnetic tape drawn to measure the amount, a laser irradiating means for irradiating a surface of the magnetic tape with a laser, a laser receiving means for receiving a laser reflected from the surface, and the laser A pull-in amount calculating unit for calculating an amount by which the magnetic tape is pulled into the gap from a displacement of a convergence point of a laser beam received by the light-receiving means; and a pull-in amount of the magnetic tape, comprising: measuring device.