JPS59157868A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To stabilize the output of a rotaty head by controlling the tape tension distribution of the tape width direction on a cylinder to keep an approximately fixed level of tape tension in the direction of the tracing length during the forward/reverse traveling of a magnetic tape. CONSTITUTION:In a normal reproduction mode when a magnetic tape 1 travels toward a solid line arrow mark, the tape 1 is guided to a cylinder 2 with the intensive tension set at the lower edge of the tape 1. When a revese motion image is reproduced as shown by a broken line arrow, an arm 16 is driven so that a tension pin 12 touches the tape 1. Then the tape 1 is guided to the cylinder 2 with the tension set at the upper edge of the tape. As a result, the rather intensive tape tension can be set for the lower edge side where a rotary head touches the tape 1 at the cylinder input side 8 where the tape tension is not intensive. Thus the tension of the tape 1 can be set nearly even when the tape is traced by the rotary head, and therefore a stable output is secured for the rotary head.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] This invention involves pulling out a tape from a tape cassette, winding the tape at a predetermined angle around a cylinder having a built-in rotating head, and using the rotating head to rotate the tape in the longitudinal direction of the tape. The present invention relates to a helical scan type magnetic recording and reproducing device that records and reproduces video signals obliquely.

[Prior art]

As is well known, in a helical scan type VTR, during playback, the tape is run at a tape speed different from the tape speed during recording, and a high-speed playback image or a reverse motion image is played back. FIGS. 1 and 2 show the state of tape running on a cylinder in which magnetic recording and reproduction are performed using a rotating head. During normal playback when the tape 1 runs in the direction of the arrow shown by the solid line, the tape 1 is lower than the tape tension at the cylinder entry side 8 where the tape 1 starts winding onto the cylinder '2.
The tape tension on the cylinder exit side 9 where the tape moves away from the cylinder 2 is thicker by the amount of friction loss on the cylinder 2. On the other hand, when reproducing a reverse motion image in which the tape 1 runs in the direction indicated by the dashed arrow, the tape tension on the cylinder exit side 9 becomes smaller than the tape tension on the cylinder entrance side 8. FIG. 2 shows a head tracing locus on the tape 1 by the rotating head. The rotating head traces the tape 1 diagonally, and contacts the tape 1 at the lower end 10 of the tape on the cylinder entry side 8, and on the cylinder exit side 9.
Then, the upper end side 11 of the tape comes into contact with the tape 1.

This conventional magnetic recording/reproducing device has the following problems.

In order to obtain a sufficient output from the rotary head during magnetic recording and reproduction, it is necessary to maintain stable contact between the rotary head and the tape 1. For this purpose, the tape 1 in contact with the rotating head is
It is necessary to increase the tension to a minimum value. but,
If the tape tension is made thicker, the amount of wear on the rotating head due to contact with the tape 1 will increase, friction loss due to tape running will increase, and tape edge damage will occur due to interference between the tape guide member and the edge of the tape 1. Problems such as increased damage to the Therefore, it is necessary to set the tape tension within an appropriate value range. However, as mentioned above, in a conventional magnetic recording/reproducing device in which there is a tape tension distribution in the tape length direction on the tape during the period when the rotating head is in contact with the tape 1, the rotating head and the tape 1 are In order to always maintain a good contact condition on the tape, the tape tension on the side with the smaller tape tension on the cylinder is set above a certain value, so the tape tension on the side with the larger tape tension on the cylinder is This results in the problem that the size becomes larger than necessary.

[Purpose of the invention]

The purpose of the present invention is to maintain good contact between the tape and the rotating head at all times when the tape is running forward or backward, to obtain stable output from the rotating head, to reduce friction loss during tape running, and to reduce the tape edge by a guide. The aim is to prevent damage to the

[Summary of the invention]

The feature of the present invention is that by adjusting the tape tension distribution in the tape width direction on the cylinder when the tape runs in the forward and reverse directions, the tape tension on the tape traced by the rotating head is adjusted in the length direction of the trace. The goal is to keep it almost constant. As a result, the output of the rotary head can be stably obtained without applying excessive tape tension, and at the same time, it is possible to reduce friction loss due to tape running and prevent damage to the tape edges.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIG.

In FIG. 3, numeral 3 is a tape cassette in which the tape 1 is stored. 12 is a tension pin, and as shown in FIG. 4, the tension pin 12 is installed on a rotating arm 13 that rotates about a shaft 14. The bottle 15 is mounted on the rotating arm 13 and engages with the arm 16 to move together.

The arm 16 is changed in position by another drive means (not shown) and operates according to the forward and backward running modes of the tape.

The arm 1 is moved so that the tension pin 12 is in contact with the tape 1 when the tape runs in the direction of the arrow shown by the broken line in FIG.
6 is driven. At this time, the tension pin 12 is implanted in the rotating arm 13 so as to strongly abut on the upper end side of the tape 1. When the tape runs in the direction of the solid arrow in FIG. 3, the tension bin 12 moves away from the tape 1. Guide rollers 4 and 6 have a structure that allows the height of the tape 1 to be adjusted. Reference numerals 5 and 7 indicate inclined gainers, which have a structure in which the tape tension in the width direction of the tape can be adjusted, and are set to increase the tape tension on the lower end side of the tape.

A cylinder 9 is inclined at a predetermined angle with respect to the length direction of the tape 1. A capstan 17 drives the tape to run in forward and reverse directions.

The operation of an example of the device of the present invention described above will be explained.

During normal playback in which the tape 1 runs in the direction indicated by the solid arrow in FIG. 3, the tape 1 is guided to the cylinder 2 with the tape tension at the lower end set strong. When reproducing a reverse motion image in which the tape 1 runs in the direction of the arrow shown by the broken line in FIG. 3, the tape 1 is guided to the cylinder 2 with the tape tension at the upper end set strong. As a result, during normal playback, the tape tension can be set to be strong at the lower end of the tape where the rotary head contacts the tape 1 on the cylinder entrance side 8 where the tape tension is weak. Therefore, the tape tension on the tape 1 traced by the rotary head is set to be almost uniform, and the output of the rotary head can be stably obtained. Furthermore, since the overall tape tension can be set while the tape tension of the cylinder/inlet side 8 is weak, friction loss due to tape running can be reduced, and damage to the tape edge caused by the guide can be prevented. On the other hand, when reproducing a reverse motion image, the tape tension can be set to be strong on the upper end side of the tape where the rotary head contacts the tape 1 on the cylinder exit side 9 where the tape tension is weak. Because of this, does it have the same effect as the normal playback mentioned above? Obtainable.

In addition, the tape tension is shifted from the optimum value by periodic changes in tape tension due to the influence of the tape running drive system. .

FIG. 5 shows another embodiment of the tension pin used in the present invention, and this embodiment has a tension pin 18 having 17 spring portions on the shaft 14. Fix with screws and tighten spring part 1
The tension pin 18 is pressed against the tape IK by the spring force of 7, thereby preventing the tape tension from decreasing.

Does this configuration have the same effect as the above-mentioned embodiment? able to demonstrate.

〔Effect of the invention〕

According to the present invention, in a helical scan type magnetic recording and reproducing device, the tape tension on the trace traced by the rotating head can be set almost uniformly, and magnetic recording and reproducing by the rotating head can be performed stably. In addition, since the tape tension of the entire device can be set to the lowest level, friction loss due to tape running can be completely reduced, and the tape edge may be damaged due to the tape guide. It is preventable.

[Brief explanation of drawings]

FIG. 1 is a front view of a conventional magnetic recording/reproducing device, FIG. 2 is a diagram showing a trace pattern of a rotary head drawn on a tape, and FIG. 3 is a front view of an embodiment of the device of the present invention. FIG. 4 is a perspective view showing one embodiment of the structure of the tension bin used in the present invention, and FIG. 5 is a perspective view showing another embodiment of the tension bin used in the present invention. DESCRIPTION OF SYMBOLS 1... Tape, 2... Cylinder, 3... Tape cassette, 4, 6... Guide roller, 5.7... Inclined guide, 8... Ninder side, 9... Cylinder exit side, 1°...Tape lower end side where the rotating head and tape contact on the cylinder entry side, 11...Tape upper end side where the rotating head and tape contact on the cylinder exit side, 12...Tension bin; 13...Rotating arm. Figure 1 Figure 2 Figure 3 Figure 4- Figure 1.3 l Day 5

Claims (1)

[Claims] 1. A magnetic tape is pulled out from inside the tape cassette by a tape pull-out means, the magnetic tape is wound at a predetermined angle around a cylinder containing a rotating head, and the rotating head moves the υ tape in the longitudinal direction. In a magnetic recording and reproducing device that performs magnetic recording and reproducing obliquely to the tape and selectively runs the tape in the forward and reverse directions, when the tape is running in the forward and reverse directions, in either case, or in both cases. 1. A magnetic recording and reproducing device characterized in that at least one tension pin is brought into contact with the tape for adjusting the tape width direction 77737 distribution of the tape on the cylinder. 2. The tension bin is installed on a rotatable rotating arm, and by rotation of the rotating arm, the tension bin is brought into contact with the tape at an angle to the tape running surface at a position outside the cylinder. A magnetic recording and reproducing apparatus according to claim 1.