JPS6213245Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tape running device equipped with a tape tension regulator.
When applied to a VTR (recording and reproducing device), it is possible to improve so-called tape noise, jitter, wow and flutter, etc.

Generally, the amount of tape wound on the supply reel changes from moment to moment (that is, the diameter of the tape wound on the supply reel changes from moment to moment), so the load on the supply reel portion changes constantly. Furthermore, the frictional force of the rotating drum, rotating guide, etc. against the tape is constantly changing. These changes are factors that change the tape tension, so-called tape tension.

However, when the tape tension changes due to these factors, the relative speed of the tape to the rotating head changes, resulting in skew distortion where the top of the playback screen curves, and so-called jitter where the screen swings unstably in the horizontal direction. This will cause the image quality to deteriorate.

Conventionally, as shown in FIG. 1, a tension regulator has been proposed which controls the tape so that a constant tape tension is always applied even if the load on the supply reel changes.

In this FIG.
It is freely rotatable around a. Also, 2
is the tension post, 3 is the return spring,
4 is a band brake, 5 is a supply reel, 6 is a rotating head drum, 7 is a capstan, 8 is a pinch roller, and 9 is a take-up reel. Here, the tape 10 runs in the order of supply reel 5 → tension post 2 → rotary drum 6 → capstan 7 → take-up reel 9.

In this case, for example, when the load on the supply reel 5 increases and the tape tension becomes stronger, the tension arm 1 is pulled in the direction in which the band brake 4 wound around the supply reel 5 loosens (direction a in Figure 1). As it is stretched, the tape tension is weakened. Conversely, for example, when the load on the supply reel 5 becomes smaller and the tape tension becomes weaker, the tension arm 1 moves in the direction in which the band brake 4 is tightened (see Fig. 1b).
direction), the tape tension is strengthened.

Therefore, the tape tension is controlled to be constant at all times by this tension regulator.

However, since this tension regulator is mechanically controlled, if the tape tension changes rapidly, for example if it changes periodically with a short cycle, it may There is an inconvenience that you will not be able to follow.

By the way, since the tape 10 runs through the tension post 2 which is set up at the free end of the tension arm 1, the tension post 2 is constantly rubbed by the tape 10. The fine fluctuations in this frictional force cause high frequency vibrations in the tension arm 1 itself.
This vibration is, for example, moving the tension post 2 in the directions of arrows a and b in FIG. 1, or moving it up and down in the front and back directions of the paper in FIG. here,
This vibration frequency is close to the elastic natural vibration frequency of the tension arm 1 and is a relatively high frequency, for example, about 180 Hz or 800 Hz. Furthermore, the tape with a tape surface having poorer smoothness has a larger coefficient of friction μ, so the vibration amplitude becomes larger.

At this time, the tape tension of the tape 10 changes in synchronization with the vibration frequency, and the larger the vibration amplitude is, the greater the change occurs.

However, as mentioned above, such conventional tension regulators were unable to follow this rapid change in tape tension. Therefore, the relative speed of tape 10 to the rotating head varied in response to changes in tape tension. As a result, skew distortion and jitter occur on the playback screen, resulting in deterioration of image quality, such as so-called water distortion.
This causes a flow phenomenon (screen fluctuation) and increases wow and flutter in the reproduced sound, and furthermore, the tension post 2 and the tape 10 ripple,
This caused so-called tape squeal.

The present invention has been developed in view of this point, and suppresses vibrations of the tension arm 1 and tension post 2 caused by friction of the tension post 2 with the tape 10, thereby reducing skew distortion and It is an object of the present invention to provide a tape running device capable of reducing jitter, wow/flutter, and tape squeal.

Hereinafter, one embodiment of the tape running device of the present invention will be described with reference to FIGS. 2 to 5. In these FIGS. 2 to 5, parts corresponding to those in FIG. 1 are given the same reference numerals, and respective explanations will be omitted.

In this example, as shown in FIG. 2, one end of a rectangular presser plate 11 made of an elastic body such as vinyl chloride resin is fixed to the upper part of the upper fixed drum 6a constituting the rotating head drum 6 with screws 12, for example. ing. Then, when the tension post 2 is moved to the tape loading position, the other end, that is, the free end of the presser plate 11 is brought into contact with the head of the tension post 2. Specifically, as shown in FIG. 3A, a tapered surface 2a is formed on the head of the tension post 2, so that this tapered surface 2a and the free end of the presser plate 11 are at the same height position. Eggplant. That is, when the tension arm 1 swings from the initial position shown by the dashed line in FIG. 4 to the tape loading position shown by the solid line, the tapered surface 2a of the head of the tension post 2 moves to the position shown in FIG. As shown, it abuts against the end face of the presser plate 11 and is pushed up, so that the head of the tension post 2 is finally positioned below the presser plate 11 as shown in FIG. 3C.

Note that 6a is an upper fixed drum of the rotary head drum 6. Also, attach the presser plate 11 to the tension post 2.
When the tension regulator is brought into contact with the head of the tension regulator, it is important that the pressing force caused by such contact be such that the function of the tension regulator itself is not impaired.

According to such a configuration, vibrations of the tension arm 1 and the tension post 2 can be suppressed. That is, the presser plate 1 is attached to the head of the tension post 2.
By bringing tension arm 1 into contact with
A vibration system consisting of the holding plate 11 in addition to the tension post 2 has been newly constructed, and the mechanical impedance of the vibration system has become sufficiently large at the conventional natural frequencies (resonance points) of about 180 Hz and 800 Hz. As a result, vibrations of the tension arm 1 and tension post 2 are suppressed, and skew distortion, tape sound, jitter, and wow/flutter caused by such vibrations can be reduced.

Specifically, when the tension post 2 vibrates in the vertical direction in the figure as shown in FIG. It is thought that the vibration of the tension post 2 is suppressed as a result.

Further, even when the tension post 2 is vibrating from side to side in the figure, for example within the range shown by the dashed line as shown in FIG. 5, the free end of the presser plate 11 is also vibrating in the vertical direction in the figure. This is because when the tension post 2 is tilted from the solid line position in FIG. 1
This is because when the tension post 1 is pushed up and the tension post 2 returns to the solid line position, the presser plate 11 is displaced downward by the return force. It is thought that such vibrations are also in opposite phase and have the same period as the vibrations of the tension post 2, so that the vibrations of the tension post 2 can be suppressed. Furthermore, in this case, the head of the tension post 2 slides on the lower surface of the presser plate 11, and the mechanical impedance increases further due to the frictional resistance accompanying this sliding, thereby preventing vibration of the tension post 2. it is conceivable that.

As described above, according to the tape running device of the present invention, the head of the tension post 2 is held down by the presser plate 11, thereby sufficiently increasing the mechanical impedance at the previous resonance point, so that the tension arm 1 and the tension Since the vibration of the shock absorber 2 is suppressed, tape squeal, jitter, wow/flatter, and skew distortion caused by such vibration can be reduced. Moreover, this advantage can be achieved by an extremely simple configuration of simply adding the presser plate 11.

The vibration of the tension arm 1 itself is caused by the friction of the tape 10 against the tension post 2, so it is especially important to avoid using so-called bad tapes that have poor tape surface smoothness and a large coefficient of friction μ. The effect becomes noticeable when used.

Incidentally, according to this example tape running device, the conventional tape running device is 0.46
% wow/fluttering value could be reduced to 0.23%. Also, tape squeal no longer occurs.
Furthermore, the vibration component of the tension regulator mechanism has been improved by 15 to 20 dB.

In the above embodiment, a sheet made of vinyl chloride resin is used as the presser plate 11 and is attached to the upper fixed drum 6a of the rotating head drum 6, but other elastic bodies may be used as the presser plate 11. Also, the mounting position is the upper fixed drum 6.
In addition to a, any other location may be used as long as the vibrations of the vibration system of the tension regulator, such as the chassis, are not transmitted.

Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments, and can be modified in various ways without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a conventional tape running device, FIG. 2 is a perspective view showing essential parts of an embodiment of the tape running device of the present invention, and FIGS. 3 to 5 are each an embodiment of the above-described embodiment. FIG. 1 is a tension arm, 2 is a tension post, and 11 is a presser plate.

Claims (1)

[Scope of utility model registration request] Guide means for guiding the tape-shaped body or support for this guide means so that the head of the tension post provided on the tension arm constituting the tape tension regulator faces the position where the tape is running. 1. A tape running device characterized in that a holding plate having a predetermined elasticity is provided on a supporting body, and the head of the tension post is pressed by the holding plate when the tape is running.