JPH03273551A - Tape tension controller for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the sag, etc., of a tape and to decrease the defect of recording and reproduced image quality by strongly driving a reel motor if a tension value is below the prescribed threshold lower than an adequate value, thereby rapidly controlling the tension value is below the prescribed threshold lower than an adequate value, thereby rapidly controlling the tension value to the adequate value. CONSTITUTION:A tension detecting lever 15 and a photointerruptor 20 detect the tension value by the displacement of a tension arm and the output of the photodetecting light quantity of the photointerruptor 20 is applied via an amplifier 21 to a comparator 22 and a 1st motor driving section 23. The comparator 22 discriminates the tension value by the threshold value Vref to a prescribed level. The discrimination output is applied to the 1st motor driving section 23 and a 2nd motor driving section 24. The 1st motor driving section 23 drives the reel motor 25 until the adequate value is attained when the tension value exceeding the threshold is detected. The 2nd motor driving section 24 drives the reel motor 25 and sharply increases the tension value when the tension value is between the threshold value. The generation of the defect of the recorded image quality by the sag of the tape is lessened in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing device, and particularly to a tape tension control device used in a magnetic recording and reproducing device such as a camera-integrated tape recorder.

[Conventional technology]

In conventional magnetic recording and reproducing devices, a tension arm that moves according to the tape tension is used as a control device to keep the tape tension constant.The position of the arm is detected by a photo-ink rubber, and the tension is adjusted when the tape tension changes from the appropriate value. A control device that controls the rotational torque of the motor that rotates the reel stand by detecting the displacement of the arm with a photo ink rubber, and maintains the tension value at an appropriate value by returning the tension arm to a predetermined position. is used.

[Problem to be solved by the invention]

However, although such a control device is effective when the fluctuations in tape tension are small, when the fluctuations in tape tension are large and especially when the tension becomes extremely low as shown in Fig. 4(a), the tension cannot be controlled. In other words, the tension arm is biased against the tape until it can rotate, but after the rotation range is exceeded, the tape separates from the tension arm and loosens, causing the tape tension to exceed its proper value. It will be lower than that. Therefore, an appropriate contact pressure to the head cannot be obtained, resulting in poor recording and reproduction image quality. Although these drawbacks can be improved by widening the rotational range of the tension arm, this has not been a fundamental solution. In particular, camera-integrated VTRs and separate-type portable video tape recorders are likely to be subjected to vibrations and shocks during recording, and the drawback is that the vibrations and shocks can cause a drop in tension or loosening of tension, resulting in poor recorded image quality. was there.

The present invention has been made in view of the problems of conventional magnetic recording and reproducing devices, and is designed to prevent the tension value from decreasing excessively even when the tape tension decreases, and to prevent the recorded image quality from deteriorating. The technical challenge is to do so.

[Means to solve the problem]

The present invention has a supply reel stand that supports a supply reel that supplies magnetic tape, a reel motor connected to the supply reel stand, and a tension post that tensions the magnetic tape at one end, and is rotatable with respect to the base. a freely supported tension arm; a biasing spring that biases the tension arm so that the tension post of the tension arm contacts the magnetic tape; and a tension value detection means that detects a tension value based on displacement of the tension arm; a comparison means for discriminating the tension value obtained from the tension value detection means, in which a predetermined threshold level is set lower than the tension value of the tension value; A first motor drive unit that drives the reel motor by the output; and a second motor drive unit that drives the rotational torque of the reel motor in a direction in which the tension increases when a tension value that is equal to or less than a threshold level is detected by the comparison means. It is characterized by having the following.

[Effect]

According to the present invention having such characteristics, the tension value is controlled by a reel motor that rotates a supply reel stand that supplies the magnetic tape.

Then, a tension value is detected by detecting the displacement of the tension arm, and the values are compared by a comparing means, and when a predetermined threshold value is exceeded, the reel motor is driven by the first motor drive unit to set the tension value to an appropriate value. It is controlled as follows. Then, when the tension arm is largely displaced and becomes below a threshold value set at a level lower than the appropriate tension value, the second motor drive section drives the reel motor to rapidly increase the tension value. . If the tension value exceeds the threshold value, the first motor drive unit again controls the tape tension value to a proper value.

〔Example〕

FIG. 2 is a schematic diagram showing a tape running path of a tape tension control device of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. In the figure, a magnetic tape 3 is supplied from a supply reel stand 2 in a tape cassette 1 during recording or reproduction. The magnetic tape 3 is stretched on a tension post 6 via cassette posts 4 and 5 in the tape cassette 1.

Then, along the running path of the magnetic tape 3, the P1 post 7° full-width erase head 8. P2 post 9 and entry side inclined post 1
0 is arranged and travels in the direction of the arrow X via the cylinder 11.

FIG. 1 is a diagram showing the detailed configuration of the tape tension control device according to this embodiment. In this figure, the tension post 7 is provided at one end of the tension arm 12.

The tension arm 12 has a fixed shaft 13 attached to the base.
A tension arm spring 14 is provided between the hook 12a at one end and the base, and biases the tension arm and the tension post 7 at its tip in the direction of arrow A. There is. Further, a tension detection lever 15 is integrally attached to the tension arm 12. As shown in FIG. 1, the tension detection lever 15 has a protrusion 1 whose lower end is bent and whose tip is notched at an acute angle.
5a. The protruding piece 15a is the photo interrupter 2
The tension detection lever 15 is arranged between the light emitting and receiving parts of the
is configured to be able to detect the angle of Here, the tension detection lever 15 and the photo ink club 20 constitute a tension value detection means that detects the tension value based on the displacement of the tension arm.

Now, as shown in FIG.
is applied to the motor drive section 23 of.

The comparator 22 has a threshold value Vref at a predetermined level lower than the appropriate value of the tape tension, and discriminates the tape tension value based on the threshold value. The signal is applied to the drive section 24 . The first motor drive section 23 drives the reel motor 25 so that the tension value becomes an appropriate value based on the tape tension value obtained from the photo ink printer 20 when the comparator 22 detects a tension value exceeding the threshold value. It is what drives the. Also, the second motor drive section 24
When the comparator 22 detects a tape tension value below a threshold value, the reel motor 25 is driven in a predetermined direction to rapidly increase the tape tension value.

Next, the operation of this embodiment will be explained with reference to time charts. FIG. 4(b) is a diagram showing the change over time in the tension value of the tension control device according to this embodiment. Now, if the tape tension value is close to the appropriate value, comparator 2
A comparison output is given from 2, and the reel motor 25 is driven by the first motor drive section 23, and the tension value is set within an appropriate range by controlling the pack tension value. In this way, the leftward moment applied to the tension post 7 and the rightward moment of the magnetic tee 13 are balanced by the tension spring 14, and the tension value is maintained at an appropriate value.

Now, if the magnetic recording/reproducing device is subjected to vibrations, shocks, etc. at time tl, and the tension value suddenly decreases as shown in FIG. , a comparison output is given to the second motor drive section 24. In this case, the reel motor 25 is strongly driven in the direction of arrow B by the motor drive section 24. This causes the tension arm 1 to rotate clockwise due to the back tension of the magnetic tape 3, and the tension value returns to near the proper value. If the threshold value Vref is exceeded, the first motor drive section 23 will once again perform control corresponding to the tension value.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the tension value is discriminated based on a predetermined threshold value that is lower than the appropriate value, and if the tension value is below the threshold value, the tension value is quickly changed to the appropriate value by strongly driving the reel motor. It is controlled so that Therefore, even if vibrations or shocks are applied to the VTR, it is possible to prevent the tension of the magnetic tape from extremely decreasing or the tape from sagging, and it is possible to stabilize the tension of the tape entering the cylinder. Therefore, an appropriate contact pressure to the head can be obtained, and it is possible to reduce defects in recording and reproduction image quality.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing the configuration of the main parts of a tape tension control device in one embodiment of the present invention, FIG. 2 is a schematic configuration diagram of the same embodiment, and FIG. 3 is an electrical configuration of the same embodiment. The block diagram and FIG. 4 are time charts showing temporal changes in tape tension values. 1--Tape cassette 2--Supply reel stand 3--Magnetic tape 6--Tension post 12--Tension arm 14--
...Tension spring 15--Tension detection lever 20--Photo interrupter 22-
- Comparator 23 - - First motor drive section 24 -
-------Second motor drive section 25・〜----
・Reel motor.

Claims (1)

[Claims] (1) A supply reel stand that supports a supply reel that supplies magnetic tape, a reel motor connected to the supply reel stand, and a tension post that stretches the magnetic tape at one end, and is rotated with respect to the base. a tension arm movably supported; a biasing spring that biases the tension arm so that a tension post of the tension arm contacts the magnetic tape; and a tension value that detects a tension value based on displacement of the tension arm. a detection means; a comparison means for discriminating a tension value obtained from the tension value detection means, wherein a predetermined threshold level lower than a proper tension value is set; and a comparison means for discriminating a tension value obtained from the tension value detection means; a first motor drive unit that drives the reel motor based on the output from the tension value detection means; and when the comparison means detects a tension value below a threshold level, the tension increases the rotational torque of the reel motor. a second motor drive unit that drives in the direction;
1. A tape tension control device for a magnetic recording and reproducing device, comprising: