JPH0115938B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating head type magnetic recording/playback device (VTR), in which the tape speed is increased from the normal playback state and when the tape is shifted to high-speed playback, the tape is not damaged. It is designed to allow for a smooth transition.

As is well known, in magnetic recording and playback devices such as VTRs, in order to compensate for the difference in tape tension due to the difference in reel winding diameter between the start and end of the reel and to stabilize tape running, the supply side is adjusted according to the strength of the tape tension. Usually, the reel is provided with a tension control mechanism for adjusting and applying the brake by means such as a band brake. By the way, in recent years, tapes have been fast-forwarded at several times to several tens of times the normal playback speed.
Alternatively, a technology has been put into practical use in which the tape is allowed to rewind and then played back in that state.

However, operating the tape tension control mechanism during high-speed playback would result in too large an increase in tape tension due to the brake sliding on the supply reel. Inside, it is necessary to release the tension control mechanism. However,
When switching from normal playback operation to high-speed playback, if the tension control mechanism is released at the same time as the rotation of the capstan and take-up reel changes to high speed, problems will occur in terms of stable tape running and tape damage. has been confirmed. That is, if the tension control mechanism is released at the same time as the tape changes from normal playback to high-speed playback, the back tension of the tape will momentarily become zero or extremely small. Touching the tape head on the input side may become unstable, causing noise at the top of the reproduced television image, resulting in an unsightly screen. Another problem is that the tension just before reaching the capstan is relatively small compared to the tension immediately after it is sent from the capstan by the pinch roller, making the tape running unstable and causing the tape to run from the regulation post just before the capstan. Damage to the tape may occur due to it coming off or becoming wrinkled.

Experiments have shown that if the release of the tension control mechanism is delayed and the tape is maintained at a predetermined tension for a short period of time (approximately 0.5 seconds) immediately after switching from normal playback to high-speed playback, the above problems can occur. It has been confirmed that it enables beautiful high-speed playback images and stable driving without looking at the screen. Note that this phenomenon is effective for fast-winding playback, and is not necessary for fast-rewind playback.

Also, during high-speed playback, it is effective for stable tape running to apply a very light brake load (there is no need to consider the load amount for the difference in winding diameter) instead of not operating the tape tension control mechanism. It is recognized that Therefore, in the embodiment, a soft brake dedicated to early winding is also used.

Next, one embodiment of the present invention will be described in detail below.

FIG. 1 shows a tape running system according to an embodiment of the present invention, and also shows a state in which the tape has completed loading into a normal playback running state.

1 is a cassette, and tape from reels (not shown) mounted on reel stands 3 and 4 is passed from a guide post 2 in the cassette to an impedance roller 1.
2, erase head 13, rotation regulating roller 1
5. Through the inclined fixed guide post 16, head cylinder 18, inclined guide post 16', rotation regulating roller 15', impedance roller 12', audio and control signal head 20, fixed regulating post 21, capstan 23, and pinch roller 22. leading to. 5 is a band brake of a tension control mechanism, one end of which is fixed to a fixed end 6, and the other end rotatably engaged with a tension lever 8 by an engagement member 7. The tension lever 8 is configured to be rotatable about a fulcrum 9, and is urged to rotate counterclockwise by a spring 10. Further, a tension post 11 is fixed to the tip thereof. During normal playback, the tension post 11
As shown in the figure, it is interposed between the guide post 2 of the cassette and the impedance roller 12.

14, 14' are guided by guide grooves 19, 19' provided on the substrate at the base of the guide post, and are moved, and are correctly positioned by stoppers 17, 17' when tape loading is completed. Also, 5
0 is a soft brake for fast-forward playback (described later in FIGS. 7 and 8).

FIG. 2 shows the tape loading mechanism related to activation and release of the tension control mechanism, and
Indicates the state at the time of unloading.

Reference numeral 25 is a loading motor, and its rotation is controlled by belts 30, 31 and pulleys 26, 27, 2.
It is transmitted to the pulley 32 via 8 and 29. The rotation transmitted to this pulley 32 is further transferred from a small gear 33 integrated with this pulley 32 to a gear 3.
4 and 35, groove cams 37 and 4 are formed on both sides, respectively.
8 and is transmitted to a cam disk 36 having a gear formed on its outer periphery. A pin 40 fixed to a sector gear 38 rotating around a fulcrum 39 engages with a cam 37 on the lower surface of the cam disc 36, and the cam disc 37
As the sector gear 6 rotates, the gear 41 engaged with the sector gear 38 rotates, and the gear 42 integrated with the gear 41 causes the gears 43 and 43' to rotate in opposite directions. Levers 44, 44' are fixed to the gears 43, 43', respectively.
44' is attached to levers 45, 45';
45' is engaged with the guide post bases 14, 14' by hinges, so the gears 43, 4
3', the guide post base 14,
14' is guided by guide grooves 19, 19' to the loading position (see FIG. 1).

FIG. 3 is a side view of FIG. 2 showing the loading drive relationship.

Next, FIGS. 4 and 5 show the operating state of the tension post. That is, FIG. 4 shows the state at the time of unloading. The main lever 46 has a fixed pin 49 that engages with the cam groove 48 on the top surface of the cam disk 36. During unloading, it is moved to the left and stopped, and the pin 47 fixed to the tip of the main lever 46 is fixed to the tension lever 8. Tension lever 8
is housed against the spring 10 so that the tension post 11 is located in the space 1-a of the cassette 1. The main lever 46 has the function of timing and driving the brake attachment/detachment and other mechanical operations by its movement, but the details will be omitted here.

Next, when loading is completed, the main lever 46 is moved to the right by the rotation of the cam disk 36 as shown in FIG. 5, and the tension lever 8 is rotated around the fulcrum 9 by the spring 10. It acts to add tension to the tape. Note that the guide post bases 14, 14' are positioned as shown in FIG. The purpose is to form a cam curve so that the main lever, that is, the tension lever 8, starts operating after the movement is almost completed.

Next, when switching from normal playback to high-speed fast-forward playback, a slight delay (approximately 0.5 seconds) is given after the tape is running at high speed, and a reverse rotation operation signal is sent to the loading motor. As a result, the cam disk 36 rotates in the opposite direction to that during normal playback, and as shown in FIG. 6, the main lever 46 is rotated to the left until the tension post 11 leaves contact with the tape. Move to. At this time, the amount of rotation of the loading motor, that is, the cam disk 36 may be controlled within the range until the guide post base starts the unloading operation. In this embodiment, control is performed using a rotary type position switch that is linked to the cam disk 36 and generates a control signal according to a preset amount of rotation.

It should be noted that the actuation or release action of the tension lever 8 can, of course, be achieved by using a dedicated electromagnetic solenoid, motor, or other drive source, but it is determined based on economic efficiency, space, etc. It is a good thing to do.

Next, the operating state of the soft brake for high-speed regeneration will be explained with reference to FIGS. 7 and 8.

During normal playback, as shown in FIG. 7, when the electromagnetic solenoid 63 is not energized, the slide lever 5
8 remains to the right, and the brake shoe 50' of the brake lever 50 is not in contact with the supply reel 3. However, when a high-speed regeneration signal is input, the solenoid 63 operates as shown in FIG. 58
is engaged with a solenoid 63 and a hinge 62, and 61
is slid to the left by a pin 59 fixed to the tip of an arm 60 that rotates with
The slide lever 53 is further moved in the arrow direction against the return spring 53a via the lever 55 which rotates about the lever 56 as a fulcrum. Since the pin 52 fixed to the tip of the lever 53 comes off from the brake lever 50, the brake lever 50 is rotated by the spring 51 around the fulcrum 50a, and the brake shoe 5
0' contacts the reel 3 and applies a light load as shown in FIG. When switching from high speed regeneration to normal regeneration, the electromagnetic solenoid is de-energized as described above, resulting in the state shown in FIG. 7, and the soft brake for high speed regeneration does not operate. Note that the slide lever 58 also has functions such as operating and releasing the main brake, but the details will be omitted here.

Next, FIG. 9 shows a control block diagram of this embodiment. 65 is a pinch roller actuation signal circuit, 66
67 is a delay circuit consisting of a monomulti, 68 is an inhibition circuit, and 69 is an electromagnetic solenoid drive circuit for operating the pinch roller. That is, when a fast forward playback signal is input from normal playback, the actuation signal is input from the pinch roller actuation signal circuit 65 to the inhibition circuit 68, but the fast forward playback signal circuit 6
The activation signal from 6 is delayed for a certain period of time by a delay circuit 67 and is input to an inhibition circuit 68. Therefore, after a certain period of time has elapsed, the pinch roller actuating electromagnetic solenoid drive circuit 69 is operated to press the pinch roller against the capstan. Therefore, after the pinch roller is once turned off, the pinch roller is turned on again after a while. 70 is an AND circuit, 71 is a delay circuit consisting of a monomulti, 72 is a drive circuit for the electromagnetic solenoid 63 for fast forward regeneration brake, 73 is a flip-flop circuit, 74 is a reverse drive circuit for the loading motor, and 75 is the already mentioned cam board 36. This is a position switch circuit that controls the amount of rotation.

While the pinch roller is pressed, an activation signal from the fast-forward regeneration signal circuit 66 is input to the AND circuit 70, turning on the drive circuit 72 of the electromagnetic solenoid 63 for fast-forward regeneration brake. Then, the brake lever 50 changes from the state shown in FIG. 7 to the state shown in FIG. 8, contacts the reel 3, and applies a load to the rotation of the reel 3. Then, the signal is transmitted to the delay circuit 71
After a certain period of time has passed, the flip-flop circuit 7
3 is input. Here, a position switch circuit 75 for controlling the amount of rotation of the cam disk 36 is connected to the other input terminal of the flip-flop circuit 73, and the tension lever 8 is kept in a low position until it moves to the position shown in FIG. The reverse rotation drive circuit 74 of the turning motor is operated. In other words, the tension control mechanism during normal playback is released.

As described above, during normal playback, a tension control mechanism such as a band brake operates to adjust the load on the supply reel according to the strength of tape tension so as to cover the difference in tape tension due to the difference in tape winding diameter. However, all of these operations are controlled by a rotating cam disk driven by the loading motor.

On the other hand, during high-speed (fast-forward) playback, the high-speed playback soft brake, which is controlled by a slide lever operated using an electromagnetic solenoid as a drive source, applies a load to the supply reel, and the tension control mechanism during normal playback is released. However, there is a slight delay when switching from normal playback to high-speed playback.
A rotation signal is given to the loading motor in the opposite direction to that during normal playback, and the tension control mechanism is released by rotating the cam disc.

Since the cam disk also functions as a drive source for tape loading and unloading operations, the amount of reverse rotation to release the tension control mechanism during high-speed playback described above is regulated within the range until the tape starts unloading. However, these controls are performed by a rotary position switch linked to a cam disk. This position switch also has the function of controlling other tape playback modes such as tape loading and unloading, but the details will be omitted.

With the above-described configuration, the present invention applies the soft brake for high-speed playback to the supply reel when transitioning from the normal playback state to high-speed playback, and also shifts the tape tension control mechanism during normal playback to high-speed playback. Since it is released later, stable and smooth transition can be performed without damaging the tape, and stable reproduced images can be obtained.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the tape running system of an embodiment of the present invention, Fig. 2 is a plan view showing the drive system of the loading mechanism, Fig. 3 is a side view of the same, and Fig. 4 is the tension during unloading. An explanatory diagram of the operation of the control mechanism, Figure 5 is an explanatory diagram of the operation when loading is completed,
Fig. 6 is an explanatory diagram of the operation during high speed regeneration, Fig. 7 is an explanatory diagram of the operation of the soft brake for high speed regeneration during normal regeneration, Fig. 8 is an explanatory diagram of the operation during high speed regeneration, and Fig. 9 is a control diagram. It is a block diagram. 3... Supply reel stand, 4... Take-up reel stand, 5
...Band brake, 8...Tension lever,
11... Tension post, 16, 16'... Inclined fixed guide post, 46... Main lever, 5
0...Brake lever.

Claims (1)

[Claims] 1. A tape tension control mechanism that adjusts and applies a load to the supply reel using a band brake according to the strength of tape tension due to the difference in reel winding diameter during normal playback, and operation of the tape tension control mechanism;
A tape tension control mechanism control circuit that controls release, a brake mechanism for high-speed travel regeneration that applies a load to the supply reel with a brake during high-speed travel regeneration, and a high-speed travel regeneration brake mechanism that controls activation and release of the brake mechanism for high-speed travel regeneration. a regeneration brake mechanism control circuit, and when switching from normal regeneration to high speed regeneration, supplies a signal to the high speed regeneration brake mechanism control circuit to operate the high speed regeneration brake mechanism and transmits the signal. A magnetic recording and reproducing apparatus characterized in that the tape tension control mechanism is supplied to the tape tension control mechanism control circuit through a delay circuit to release the tape tension control mechanism.