JPH03185657A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable the smooth traveling of a magnetic tape by forming plural specific shaped recessed parts on a tape traveling surface of a lower drum for guiding the tape. CONSTITUTION:An opening part 2a for exposing a magnetic head is formed on an upper drum 2 of the device for recording and reproducing a signal by winding the magnetic tape around a rotary drum, while a lead 1a for regulating a tape traveling position is formed on the lower drum 1 for guiding the tape. Plural cylindrical shaped recessed parts 1b are formed on the surface of the lower drum 1. By this method, the contact area between the surface of the lower drum 1 and the tape 3 is reduced, and the tape can be prevented from sticking to the surface of the lower drum 1 due to their surface contact, thus enabling the smooth traveling of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improving tape running characteristics, particularly in a magnetic recording/reproducing device equipped with a rotating magnetic head device.

[Prior Art] In recent years, devices such as VTRs (video tape recorders) have been rapidly miniaturized, and as a result, rotating drum units have also been inevitably miniaturized, making it possible to transfer tape to the rotating drum in a small space. The tape running path (tape bus) has become complicated as winding has to be performed.

FIG. 4 C5 An example of a downsized tape bus for, for example, an 8 mm VTR, is shown in FIG. 5 as an enlarged view of the vicinity of the tape separation area of the drum unit indicated by 4 in FIG. 4.

In FIG. 4, 4 is a rotating drum unit having magnetic heads arranged at predetermined intervals around its outer periphery, and is composed of a rotating upper drum and a fixed lower drum.

5 is a capstan for transporting the tape 3 at a predetermined speed; 6;
7 is a supply reel, and 8 is a pick-up reel.

The tape bath shown in the figure is formed by guide posts 9 to 17, in particular a movable supply guide post consisting of guide post 12.13, a movable take-up guide post consisting of guide post 14.15, and the tape 3 is drawn from a cassette (not shown) and wound around a rotating drum unit at a predetermined angle.

Reference numeral 9 is a tension regulator for detecting tape tension. Pins 10, 11, 16, and 17 are guide posts that form the tape path together with the above-mentioned guide posts 12 to 15, respectively.

In such a configuration, considering the tape running characteristics, during normal recording and playback, the tape is pulled out from the supply reel 7 with a certain tension, and then supported by each guide post, and the tape as shown in the figure is pulled out from the supply reel 7 with a certain tension. It is wrapped around the drum unit 4 with its position regulated by the running path, and then the capstan 5 is wrapped around the drum unit 4.
It is conveyed by the pinch roller 6 and wound onto the pick-up reel 8.

At this time, the tape tension gradually increases from the supply reel 7 to the capstan 5, which is the drive source for tape running.

When the tape is running in reverse, the tape is conveyed by the capstan 5 and the pinch roller 6 as soon as it is pulled out from the pick-up reel 8.

Thereafter, it is wound onto the supply reel 7 via the drum 41 and each guide post. At this time, since the tape is wound onto the supply reel 7 with a constant torque, the tension gradually decreases from the supply reel 7 to the capstan 5.

Therefore, near the tape separation point near the capstan 5 on the drum, the tension of the tape varies greatly depending on the running direction.

Therefore, when the tape is running in the normal recording or playback direction, it is stretched linearly with respect to the guide post as shown by the broken line in Figure 5, but when the tape is running in the opposite direction, the tape tension decreases as shown by the solid line. In addition, the rigidity of the tape itself also plays a role, and it has the property of running in a state where it swells and separates from the guide post, etc.

This situation becomes more apparent as the diameter of the rotating drum decreases and the angle of the tape winding increases as the device becomes smaller.

[Problem to be Solved by the Invention 1] In the above-described tape bus, when the tape runs in reverse, the tape swells away from the guide post, so the wrapping angle around the drum unit 4 increases, and the drum unit 4 and tape 3 separate. At this point, the area of contact with the drum unit increases as the tape swells, increasing the running load, making tape running unstable, putting unnecessary load on the drive system, and in the worst case scenario. There was a danger that the tape would come loose.

Generally, the lower drum of an 8mm VTR is made of Si8 to 1
2% A2 alloy or the like is used, and the surface roughness of the tape running surface is approximately 0.05 pitch of Is. However, in recent years, with the trend toward higher bands, the surface roughness of tapes has become smoother, and the running characteristics of the tapes themselves have deteriorated significantly.

Coatings are applied to reduce the coefficient of friction between the tape and drum, but they do not have good environmental resistance.

[Means for Solving the Problems] The present invention has been made for the purpose of solving the above-mentioned problems, and is a magnetic recording and reproducing device that records and reproduces signals by winding a magnetic tape around a rotating drum unit. By forming a plurality of recesses of a predetermined shape on the tape running surface of the lower guiding drum, smooth tape running is made possible.

[Embodiment] Hereinafter, one embodiment of the magnetic recording/reproducing apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an enlarged perspective view of a rotating drum unit, in which 1 is a lower drum that guides the tape, and 2 is a rotating upper drum. An opening 2a for exposing the magnetic head is formed in the upper drum, and a glue 11a for regulating the tape running position is formed in the lower drum. FIG. 2 is an enlarged view of the surface of the lower drum 1 to which the present invention is applied. Fig. 3 shows the results of testing the lower drum material with the surface treatment of the present invention and the conventional lower drum material in a high temperature environment (temperature 45°C, humidity 60%), where A shows the surface treatment of the present invention. The treated lower drum material B is the conventional lower drum material.

As shown in FIG. 1, a plurality of cylindrical recesses 1b, as shown in the enlarged view of FIG. 2, are formed on the surface of the lower drum l by, for example, laser machining.

An example of the shape of the recess is that the diameter of the recess is approximately O,
Inm, the depth is approximately 2 μm, and the pitch is approximately 0.2 mm.

Thereby, the contact area between the surface of the lower drum 1 and the tape 3 can be reduced, and sticking due to surface contact between the tape 3 and the surface of the lower drum 1 can be prevented. As shown in Fig. 3B, the Aj2 material used for the fixed lower drum, which has not been surface-treated as in the conventional invention, is exposed to a high temperature (45°C, 60%) environment at point C in Fig. 3. During this process, a phenomenon occurred in which the tape stuck to the surface of the material, making it virtually impossible for the tape to run smoothly. On the other hand, with the lower drum material subjected to the surface treatment of the present invention, the tape does not stick to the surface of the lower drum material even in high temperature environments, as shown in Figure 3A, and the coefficient of friction is lower than that of conventional materials. Since it is relatively small, smooth and highly accurate tape running is possible. As described above, when the surface of the lower drum is subjected to the surface treatment of the present invention, it is possible to prevent the tape 3 from sticking to the lower drum 1, and smooth tape running becomes possible.

Further, since the recessed portion 1b can be formed by laser processing or the like, complicated drum processing is not necessary, and the present invention can be realized without increasing costs.

[Effects of the Invention] As described above, according to the present invention, by providing minute recesses on the surface of the lower drum, the contact area with the tape can be reduced, and inconveniences such as tape sticking can be eliminated. Further, there is no need to significantly increase costs due to complicated processing, etc., and there is an effect of realizing a stable tape running state regardless of the tape running direction.

Incidentally, it is effective whether the depressions on the surface of the lower drum are in the form of spots or irregular ellipses. Moreover, it is effective even if it is applied over the entire tape running surface of the lower drum or only in the vicinity of the tape separation point.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the drum unit including the lower drum and upper drum. Fig. 2 is an enlarged view of the surface of the lower drum. Fig. 3 is the coefficient of friction between the drum material subjected to the surface treatment of the present invention and the conventional drum material. Comparison Fig. 4 is an example of a downsized tape bus for an 8mm VTR. Fig. 5 is an enlarged view of a drum unit near the tape output side. 1...Fixed lower drum 2...Upper drum 3...Tape 4... Drum unit 5...Capstan 6...Pinch roller 7...Supply reel 8...Tick-up reel 9...Tension regulator 10-17...Guide post

Claims (2)

[Claims] (1) A magnetic recording and reproducing device that records and reproduces signals by winding a magnetic tape around a rotating drum unit, characterized in that a plurality of recesses of a predetermined shape are formed on the tape running surface of a lower drum that guides the magnetic tape. A magnetic recording and reproducing device. (2) A magnetic recording/reproducing device according to claim (1), wherein the recessed portion is formed by laser processing.