JPH0746449B2 - Magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording device such as a video tape recorder (VTR).

Conventional configuration and its problems In recent years, household VTRs have become extremely popular, and many models are being developed one after another. The VTR pulls out the magnetic tape from inside the tape cassette and runs it on the rotating head cylinder to record / reproduce signals, which lengthens the tape traveling path and increases the traveling load of the tape traveling guide element. If the tape drive force is not sufficient, the tape will not run under adverse environment, which is an important problem.

Hereinafter, a conventional VTR will be described with reference to the drawings.

FIG. 1 is a plan view of a main portion of a conventional so-called VHS type VTR when the tape is running at a constant speed. Here, tape cassette (1)
Tape (3) wound around the supply reel (2) inside
Is the tension post (4), erase head (5), first
Limiter roller (6), first tilt post (7), rotating head cylinder (8), second tilt post (9), second limiter roller (10), audio control head (1)
1) Guided by the capstan (12) and pinch roller (1)
It runs at a constant speed by 3) and is wound up by the take-up reel (14). Reference numerals (15) and (16) denote a supply reel stand and a take-up reel stand provided on the substrate (17), which engage with the supply reel (2) and the take-up reel (14) and rotate integrally. It is becoming like this.

The tension post (4) is planted on a lever (19) which is rotatably arranged around a shaft (18) on the substrate (17), and the lever (19) is attached to the substrate ( 17) It is urged counterclockwise in FIG. 1 by the action of the tension spring (21) hung between the pin (20) and the pin (20).
Reference numeral (23) is a tension band having one end connected to a pin (22) erected on a substrate (17) and the other end connected to the lever (19), which is curved and formed. A friction member (24) such as a felt, which is in contact with the supply reel base (15), is attached to the inside of the curved portion.

That is, the tension post (4) is a magnetic tape (3).
When the tension of the magnetic tape (3) is weakened, the lever (19) is pulled counterclockwise in FIG. 1 by the tension spring (21) and one end of which is connected to the pin (22). Since the other end of (23) moves to the left in FIG. 1, the pressing force applied by the friction member (24) to the supply reel stand (15), that is, the braking torque applied to the supply reel stand (15), increases. , The tension of the magnetic tape (3) increases. On the contrary, when the tension of the magnetic tape (3) in the tension post (4) becomes strong, the lever (19) rotates clockwise in FIG. 1 against the biasing force of the tension spring (21). The operation opposite to the above-described operation occurs, so that the brake torque to the supply reel base (15) becomes small and the tension of the magnetic tape (3) decreases. In this way, the tension control of the magnetic tape (3) is performed.

However, in the above configuration, there are many traveling guide elements between the tension post (4) and the capstan (12), and the friction force in each element causes the tension guide post (4). Even if the tension of the magnetic tape (3) is properly controlled in the portion (), the tension in the portion of the capstan (12) increases, and there is a problem that the effect of tension control cannot be fully exerted. That is, for example, as shown in the upper column of Table 1, the tension at the portions A to H in FIG. 1 gradually increases due to the frictional force at each traveling guide element, that is, the traveling load.

In particular, the rate of increase in tension by the second tilted post (9) of the first tilted post (7) that is fixed and has a large wrap angle is large. Further, the coefficient of friction between the magnetic tape (3) and the traveling guide element increases for some reason, and for example, as shown in the lower column of Table 1, the tension of the magnetic tape (3) is 50% in the H part. Will also increase. Therefore, it is necessary to set the tape drive force between the capstan (12) and the pinch roller (13) so that there is a sufficient margin even at this time.
As a result, the pressing force of the pinch roller (13) must be made sufficiently large, which causes a problem that the bearing loss of the capstan (12) becomes large.

An object of the present invention is to make it possible to properly control the tension of the magnetic tape even when the tape driving force by the capstan and the pinch roller is reduced, and reduce the pressing force of the pinch roller to reduce the bearing loss of the capstan. It is an object of the present invention to provide a magnetic recording / reproducing apparatus having a small size.

The magnetic recording / reproducing apparatus according to the present invention is a recording / reproducing method in which the magnetic tape is pulled out of the cassette from the inside of a tape cassette containing a reel capable of winding a magnetic tape, and the magnetic tape is run in contact with a rotary head cylinder. In a reproducing apparatus, an inclined post provided on the downstream side of the rotating head cylinder for applying the magnetic tape to the lead of the rotating head cylinder, and a pinch roller on the downstream side of the inclined post in cooperation with each other. A capstan for driving the magnetic tape to run at a constant speed, a unique tension detecting means for detecting the tension of the magnetic tape between the inclined post and the capstan, and an integral unit engaged with a supply reel in the tape cassette. It is possible to apply a brake torque to the supply reel base that rotates dynamically, and the applied torque can be applied in accordance with the output of the tension detecting means. The applied torque varying means is variably configured. According to this, since the tension of the magnetic tape can be detected just before the capstan, even if the coefficient of friction between the magnetic tape and the traveling guide element changes, the tape tension is always irrelevant. Can be set appropriately, stable tape running can be made possible, and the pressing force of the pinch roller can be reduced to reduce the bearing loss of the capstan.

Description of Embodiments An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a plan view of an essential part in one embodiment of the present invention,
The same members as those in FIG. 1 are designated by the same reference numerals. The magnetic tape (3) wound around the supply reel (2) in the tape cassette (1) includes a guide post (4), an erasing head (5), a first limiter roller (6), and a first inclined post (7). , Rotating head cylinder (8), second tilt post (9), second limiter roller (10), tension post (30) (details will be described later), audio control head (11), and capstan (12). The pinch roller (13) runs at a constant speed, and the winding reel (14) winds it. The supply reel stand (15) and the take-up reel stand (16) are adapted to engage with the supply reel (2) and the take-up reel (14) and rotate integrally.

(30) is a tension post, which is a shaft (31) on the substrate (17).
It is planted at one end of a lever (32) which is rotatably arranged around. The lever (32) is urged to rotate in the clockwise direction in FIG. 2 by a tension spring (33). A light-shielding plate (34) in the tangential direction is attached to the other end of the lever (32), and this light-shielding plate (34) includes a light-emitting element (35) and a light-receiving element (3).
6) It's getting in between. Tension post (30)
Is in contact with the magnetic tape (3), and the magnetic tape (3)
When the tension of the lever increases, the lever (32) rotates counterclockwise in FIG. 2 and the amount of light to the light receiving element (36) decreases.
On the contrary, when the tension of the magnetic tape (3) decreases, the lever (32) rotates clockwise, and the amount of light to the light receiving element (36) increases. These constitute the book strength detecting means (37).

Next, the applied torque varying means (38) will be described. (23) is a tension band formed in a curved shape as in FIG. 1. Inside the curved portion, a friction member (24) such as a felt which is in contact with the supply reel base (15) is provided. It is attached. One end of the tension band (23) is connected to the pin (22), and the other end is connected to a rotating lever (40) of an actuator (39) that is rotationally displaced according to a voltage such as a galvanometer.

As the tension of the magnetic tape (3) increases, the light receiving element (36)
When the amount of light to be decreased, the rotating lever (40) slightly rotates clockwise in FIG. 2 to loosen the tension band (23). Then, the supply reel base (15) of the friction member (24)
The braking torque on the magnetic tape (3) is reduced and the tension of the magnetic tape (3) is reduced. On the contrary, when the tension of the magnetic tape (3) is reduced and the amount of light to the light receiving element (36) is increased, the rotation lever (40) is rotated slightly counterclockwise in FIG.
The tension band (23) is tense and the supply reel stand (15)
The braking torque to the magnetic tape (3) is increased and the tension of the magnetic tape (3) is increased.

When the friction coefficient between the magnetic tape (3) and the running guide element in the tape running system as described above is 0.25 and 0.4, A to H
The tape tension in each section is shown in Table 2.

As is clear from Table 2, even if the friction coefficient changes, the tape tension in the H part hardly changes, and the tape driving force by the capstan (12) and the pinch roller (13) is small when the friction coefficient is small. It should be set according to. Further, the tape tension itself in the H portion can be reduced, and for example, when the friction coefficient is 0.4, it can be reduced by about 15% as compared with Table 1. As a result, pinch rollers (13)
It is also possible to reduce the pressing force of, and the bearing load on the capstan (12) can also be reduced. This result increases as the change in the friction coefficient increases.

Although the VHS type magnetic recording / reproducing apparatus has been described in the above embodiment, it is obvious that the present invention is not limited to this. Further, although the light intensity detection type is used for the detection of the tape tension, the same effect can be expected as long as an electric output corresponding to the tape tension can be obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, 1
It is possible to run the magnetic tape with almost the same tape driving force regardless of the size of the friction coefficient between the tape and the running guide element by using two tape tension detectors. Since the device can be obtained and the pressing force of the pinch roller can be reduced,
The capstan rotation energy is small and the capstan bearing can have a long life, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a plan view of relevant parts of a conventional magnetic recording / reproducing apparatus, and FIG. 2 is a plan view of relevant parts of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. (1) …… Tape cassette, (2) …… Supply reel,
(3) ... magnetic tape, (8) ... rotating head cylinder, (9) ... second inclined post, (12) ... capstan, (13) ... pinch roller, (14) ... take-up reel , (23) …… tension band, (24) …… friction member, (30) …… tension post, (32) …… lever,
(34) ... light shield, (36) ... light receiving element, (37) ... tension detecting means, (38) ... applied torque varying means, (39) ...
… Actuator, (40) …… Rotary lever

Claims (1)

[Claims] 1. A recording / reproducing apparatus for recording / reproducing by pulling out the magnetic tape to the outside of the cassette from a tape cassette containing a reel capable of winding a magnetic tape, and recording / reproducing the recording tape by running it on a rotary head cylinder. An inclined post provided on the downstream side of the rotary head cylinder for accommodating the magnetic tape to the lead of the head cylinder, and a pinch roller on the downstream side of the inclined post to cooperate with the magnetic tape at a constant speed. A capstan that is driven to run, a unique tension detection unit that detects the tension of the magnetic tape between the inclined post and the capstan, and a supply that rotates integrally with a supply reel in the tape cassette. A brake torque can be applied to the reel base, and the applied torque is variable according to the output of the tension detecting means. A magnetic recording / reproducing apparatus comprising: