JPH0585974B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a tape guiding device for a magnetic recording/reproducing device, and more particularly to a tape guiding device for a magnetic recording/reproducing device suitable for reducing tape tension fluctuations of a magnetic tape. It is something.

[Background of the Invention] In a magnetic recording and reproducing device that records and reproduces information using a magnetic tape as a medium, the magnetic tape wound around a supply reel and a take-up reel in a cassette is generally pulled out onto a required running path, and the magnetic tape is magnetically recorded and reproduced. A plurality of tape guide posts guide the magnetic tape so that it can be wound around a rotating cylinder and run.

FIG. 2 is an enlarged view of the tape guide post.

The magnetic tape runs between the upper and lower flanges a and c of the tape guide post, and the roller member b
rotates smoothly around the axis as the tape runs. Further, in order to run the magnetic tape stably in the magnetic head portion, the tape edge is pressed against the upper and lower flanges a and c and regulated in the height direction.

However, due to limitations such as the accuracy of the individual roller member b, the assembly of the tape guide post, and the assembly accuracy,
The rotating direction of roller member b and the traveling direction of the magnetic tape do not match, and the force that presses the tape edge of the magnetic tape against flanges a and c varies with each rotation of roller member b, and the force between flanges a and c and the magnetic tape changes. ,
Since the frictional force between the magnetic tape and the roller member b varies, magnetic tape tension variation, that is, tape tension variation occurs. This tape tension fluctuation disturbs the stable running of the magnetic tape in the magnetic head section and causes deterioration of the information signal such as jitter, wow, and flutter.

Suppression of this tape tension variation is an important issue in improving playback image quality.

In the past, in addition to improving the precision of the tape guide device, for example, as described in Japanese Patent Publication No. 51-49401, a roller member with a special shape that has a larger diameter at the center was used. An attempt was made to avoid tape tension fluctuations by improving the performance of the post itself.

However, there are limitations in accuracy, manufacturing, and cost, and it has not been possible to completely eliminate tape tension fluctuations.

A plurality of tape guide posts are usually used in one magnetic recording/reproducing device, and consideration has not been given to the effect of amplifying tape tension fluctuations between the tape guide posts. That is,
With respect to the tape feeding direction, tape tension fluctuations occurring at the tape guide post on the upstream side result in pressure fluctuations on the tape edge at the tape guide post on the downstream side. If the cycle of the pressure fluctuations coincides with that of the tape tension fluctuations, the tape tension fluctuations will be amplified, leading to a problem of accelerated deterioration of reproduced image quality.

[Object of the Invention] The present invention has been made in order to solve the problems of the prior art described above, and provides a tape guide device for a magnetic recording/reproducing device that is capable of obtaining stable tape running with little variation in tape tension. Its purpose is to provide.

[Summary of the Invention] The configuration of the tape guide device of the magnetic recording/reproducing apparatus according to the present invention is such that the magnetic tape wound on the supply reel and take-up reel in the cassette is guided by a plurality of tape guide posts to guide the magnetic tape for the required travel. In a tape guiding device of a magnetic recording and reproducing apparatus, the magnetic tape is pulled out onto a path, wound around a rotating cylinder equipped with a magnetic head for recording and reproducing, and driven while the magnetic tape is pressed into contact between a pin roller and a capstan. The outer diameter of the roller members of the plurality of tape guide posts that guide the magnetic tape up to the cylinder is configured to increase in order from the supply reel side to the rotary cylinder side, and , the ratio of the outer diameters of any two roller members is 1:2, 1:3,
The outer diameter dimension is set to be different from each value of 1:4, 2:3, and 3:4.

Additionally, the idea behind developing the present invention is as follows:
It is as follows.

The amplification effect of tape tension fluctuations between tape guide posts is caused by the coincidence of the cycles of tape tension fluctuations, so it can be prevented by making the outer diameters of the roller members different and by shifting the rotation periods of the rollers. We focused on what is possible.

On the other hand, human visual perception is such that the lower the frequency of jitter, the more difficult it is to detect it, so it is desirable to keep the tape tension fluctuation period as low as possible due to the tape guide post near the magnetic head, which has a large effect on image quality.

Therefore, it was decided that the outer diameters of the plurality of tape guide posts arranged upstream of the magnetic head increase in the order of increasing distance toward the magnetic head.

Further, the problem of influence on image quality due to overlapping cycles of tape tension fluctuations occurs when the harmonics of each other are within the fourth order. In that case, the ratio of the outer diameters of the two roller members is 1:2, 1:3, 1:
There are five possible options: 4, 2:3, and 3:4.

Therefore, it is preferable to avoid these ratios for the outer diameter of the roller member, which increases in order toward the rotating cylinder.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a plan view showing a magnetic tape running path of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing tape tension fluctuations occurring in a tape guide post and their frequencies. be.

First, the overall configuration of the magnetic recording/reproducing device is explained in the first section.
This will be explained with reference to the figures.

What is shown in FIG. 1 shows a state in which the magnetic tape 3 is pulled out from the cassette 1 to a desired running path.

The magnetic tape 3 pulled out from the supply reel 2 in the cassette 1 is transferred to a pin 4, a pin 5 upright on the tension arm, a pull-out roller 6, an inclined pin 7, a full-width erasing head 8, an impedance roller 9, and an entry guide roller. 10, entry side inclined pin 11,
A rotating cylinder 12 containing a magnetic head, an output inclined pin 13, an output guide roller 14, an audio erasing head 15, an audio head 16, a capstan 17,
A running path is formed that passes through the pinch roller 18 and the guide pin 19 and reaches the take-up reel 20 inside the cassette 1.

The magnetic tape 3 travels in the direction of arrow V while being pinched and pressed by a capstan 17 driven by a capstan motor 21 and a pinch roller 18 that is in contact with the capstan 17.

Here, the tape guide post refers to the pull-out roller 6, the inlet guide roller 10, and the outlet guide roller 14.

These multiple tape guide posts are connected to the second tape guide post first.
As explained with reference to the figures, it is composed of a rotatable roller member b and upper and lower flanges a and c.

In this embodiment, there are a plurality of tape guide posts that guide the magnetic tape 3 from the supply reel 2 in the cassette 1, which is the upstream side of the magnetic head, to the rotating cylinder 12, which is the magnetic head section. The outer diameter of the roller member of the side guide roller 10 is set so that it becomes larger in order from the supply reel 2 side toward the rotating cylinder 12 side, that is, the outer diameter of the input side guide roller 1 is larger than the outer diameter of the pull-out roller 6.
The outer diameter of 0 is increased.

Next, regarding tape tension fluctuations occurring in the tape guide post, the state of overlap between harmonics will be explained with reference to FIG.

In each figure from a1 to e in FIG. 3, the horizontal axis is the frequency (Hz), and the vertical axis is the tape tension fluctuation level T (dB).

The outer diameters of the roller members of both the tape guide posts of the pull-out roller 6 and the entry-side guide roller 10 in FIG. 1 are assumed to be D ₆ and D ₁₀ . In this example, D ₁₀ is assumed to be larger than D ₆ . Also, each rotation period is
₆ and ₁₀ , and the tape speed is V (mm/sec), it is expressed by the following equations: ₆ = V/D ₆ π, ₁₀ = V/D ₁₀ π.

As in the conventional case, when the outer diameters of both the roller members of the pull-out roller 6 and the entry-side guide roller 10 are equal,
That is, when D ₆ = D ₁₀ , the tape tension fluctuations due to both roller members are as shown in Fig. 3a.
1 and a2, and when these overlap, all harmonics will be amplified as shown in FIG. 3 a3.

FIG. 3b shows a case where the third harmonic of the pull-out roller 6 and the fourth harmonic of the inlet guide roller 10 overlap.

At this time, since 3 ₆ =4 ₁₀ , 3×V/πD ₆ =4×V/πD ₁₀ ∴ D ₆ /D ₁₀ =3/4. That is, the ratio of the outer diameter of the roller member is 3:
4, a situation as shown in FIG. 3b occurs.

It is in this way that amplification that may affect image quality occurs due to harmonic overlap.
Or it is an overlap between lower harmonics up to the fourth order. FIGS. 3c, d, and e show all cases in which there is overlap between harmonics within the fourth order of each other regarding the tape tension fluctuation level caused by the roller members of both the tape guide posts of the pull-out roller 6 and the input guide roller 10. The figures show cases in which the ratio of D ₆ :D ₁₀ is 2:3, 1:3, and 1:2 in the order shown.

So, for example, if D ₆ = 4.5 and D ₁₀ = 6,
Since this tends to lead to amplification of tape tension fluctuations as shown in Figure 3b, the outer diameters of both roller members should be
If the values are set as D ₆ = 4.5 and D ₁₀ = 5.5, the first overlap will be the 9th and 11th harmonics,
Large amplification effects can be avoided.

In other words, in order to prevent harmonics of magnetic tape tension fluctuations caused by the rotation of each roller member of a plurality of tape guide posts from overlapping within the fourth harmonic, any two of these roller members are The ratio of the outer diameters of the two roller members is also 1:2, 1:
The outer diameter size may be set to be different from each value of 3, 1:4, 2:3, and 3:4.

According to this embodiment, it is possible to suppress tape tension fluctuations due to pressure on the magnetic tape edge, thereby reducing damage to the tape edge and achieving stable recording and reproduction.

In the above embodiment, the roller members of the plurality of tape guide posts are composed of two rollers, the pull-out roller 6 and the entry-side guide roller 10, but even if the number increases, the same settings can be made. Needless to say.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a tape guide device for a magnetic recording/reproducing device that can obtain stable tape running with little variation in tape tension.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a running path of a magnetic tape of a magnetic recording/reproducing apparatus according to an embodiment of the present invention;
The figure is an enlarged view of the tape guide post, and FIG. 3 is a diagram showing tape tension fluctuations occurring in the tape guide post and their frequencies. DESCRIPTION OF SYMBOLS 1... Cassette, 2... Supply reel, 3... Magnetic tape, 6... Pull-out roller, 10... Entry side guide roller, 12... Rotating cylinder, 14...
Exit guide roller, 17...Capstan, 18
... Pinch roller, 20 ... Take-up reel, 21
... Capstan motor, b ... Roller member.

Claims (1)

[Claims] 1. A magnetic tape wound on a supply reel and a take-up reel in a cassette is guided by a plurality of tape guide posts, pulled out to a required running path, and wound around a rotating cylinder equipped with a magnetic head and to be used for recording and reproduction. In a tape guide device of a magnetic recording/reproducing apparatus that drives the magnetic tape while being pressed between a pinch roller and a capstan, roller members of a plurality of tape guide posts guide the magnetic tape between the supply reel and the rotating cylinder. The outer diameter is configured to increase in order from the supply reel side to the rotating cylinder side, and the ratio of the outer diameters of any two of these roller members is 1:2, 1. :3,1:4,
1. A tape guide device for a magnetic recording/reproducing device, characterized in that an outer diameter dimension is set to be different from each value of 2:3 and 3:4.