JPH0426946A - Still reproducing system for video signal reproducing device - Google Patents

Abstract

PURPOSE:To excellently reproduce a still by making a tape travel a little after the traveling of the tape is stopped, locking a reel on a supply side thereafter, returning the tape to a regular stop position and relaxing the tension of the tape. CONSTITUTION:When the stop position of the tape is decided, a system controller 20 makes a capstan driving circuit 22 output a pulse-like driving voltage, for example, to a capstan motor 23 for a very short time. Then, a capstan 9 is turned a little and the magnetic tape 2 is moved forward (in a proceeding direction at the time of reproducing). When it is moved as long as prescribed length, a reel brake is turned on and a supply reel 3 is locked. Then, by reversely rotating the capstan 9, the tape 2 is moved backward (in the proceeding direction at the time of rewinding). Thus, the tension of the tape is lowered and an accident that the tape is damaged hardly occurs even when the still is continuously reproduced for a long time under such a state.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a still playback method for a video signal playback device. After stopping the tape running, drive the capstan without locking the rotation of the supply reel to run the tape slightly forward (running direction during playback), and then stop the rotation of the supply reel. By locking the tape and rotating the capstan in the opposite direction to return the tape to its original stop position and stop it, it is possible to reduce the tape tension during still operation without any control over the tension regulator. It has been made possible.

[Prior Art] In a video signal reproducing device (hereinafter referred to as a VTR) that uses magnetic tape as a video signal recording medium, when a pause operation is performed during playback, the tape running is usually stopped and the scanning by the rotating head drum is stopped. By continuing,
Continuous playback (so-called still playback) of recorded video signals on the same track is performed.

Incidentally, it is known that a VTR uses a mechanical tension regulator (hereinafter referred to as a tension arm) to provide a constant tape tension while the tape is running. It is not preferable to apply the same tape tension as when the tape is running. This is because during a still operation, the rotary head drum rotates at the same position on the magnetic tape, so if the still operation continues for a long time, the magnetic tape is likely to be damaged.

Therefore, during still operation, it is necessary to lower the tape tension so that the magnetic tape can withstand still operation for a long time.

Conventionally, there has been a technique in which a tension arm mechanism is provided with an opening mechanism using a plunger or the like to reduce the tension applied to the magnetic tape by the tension arm during still operation.

[Problems to be solved by the invention] However, in order to realize such a tape tension control mechanism, it is inevitable that the tension arm mechanism becomes complicated, and power consumption increases to drive the plunger. There was a problem. Furthermore, if the tape tension applied by the tension arm is loosened during still playback, the magnetic tape will move slightly toward the tension arm (usually closer to the supply reel than the head drum) and the tape stop position will change, causing still playback. There are also problems such as noise on the screen and inconveniences when step playback (frame-by-frame playback) or slow playback is performed after a still image.

[Means for Solving the Problems] The present invention has been made in view of the above problems, and it is possible to reduce the tape tension without changing the tape stop position during still playback without making the mechanism complicated. (The aim is to achieve this very easily.)

In other words, in a VTR, a mechanical tension regulator is used to always give a constant tape tension, and when performing still playback, the capstan is stopped to stop tape running, and then the supply reel is turned off. The capstan is driven without locking the rotation to cause the magnetic tape to travel slightly in the forward direction, and then the rotation of the supply reel is locked and the capstan is reversed to return the magnetic tape to its original stop position. This is to stop the engine.

[Operation] After stopping tape running with a still command, the tape is allowed to run slightly, and then the supply reel is locked and returned to the original stop position. It becomes loose and the stopping position does not change.

[Example] Figure 1(a) shows a V in which the still reproduction method of the present invention is adopted.
It shows the tape running mechanism (loading state) of the TR.

In the figure, 1 is a tape cassette, 2 is a magnetic tape, 3 is a supply reel, and 4 is a take-up reel. Further, 5 is a loading ring that rotates during loading operation, 6 is a leading guide provided on the loading ring, 7 is a rotating head drum, 8 is a tension arm, 9 is a capstan, 1
0 is a pinch roller.

Further, a control system circuit block of these tape running mechanisms is shown in FIG. 1(b).

20 is a system controller for tape running control;
It is formed by a microcomputer consisting of a CPU, ROM, RAM, and interface. This system controller 20 receives user operations (panel button or remote commander operations) from an operation signal generation section 21.
Based on this, operation command information such as "playback", "record, !lli' fast forward", "stop at -", etc. is supplied.

Further, the system controller 20 is supplied with various information necessary for tape running operation control, such as a cassette detection signal, reel FG, capstan FG, etc., from each sensor means.

A capstan drive circuit 22 supplies a drive voltage to the capstan motor 23 under the control of the system controller 20 to rotate the capstan 9. During recording and reproduction, a servo loop is formed by supplying a capstan FG (rotation detection signal) to the system controller 20, and constant speed rotation is controlled.

A reel drive circuit 24 supplies a drive voltage to the reel motor 25. The supplied drive voltage is controlled by the system controller 20 so as to change the reel rotational speed during playback, variable speed playback, fast forwarding, etc.

26 is a brake plunger drive circuit, which outputs a stop command,
- When a stop command is supplied to the system controller 20, the reel brake 27 is turned on to brake the reel rotation.

A drum drive circuit 28 drives the drum motor 29 at a constant speed to rotate the rotary head drum 7 during recording, playback, variable speed playback, and the like.

3o is a loading drive circuit, which drives the loading motor 31 when the tape cassette 1 is loaded in the VTR and the cassette detection signal is supplied to the system controller 20, thereby driving the loading ring 6.
rotates, the magnetic tape 2 is pulled out from the tape cassette 1 by the leading guide 7, and the pulled out magnetic tape 2 is held between the pinch roller 10 and the capstan 9, as shown in FIG. 1(a). It is said to be in a driveable condition.

Note that due to this loading operation, the tension arm 8 is simultaneously rotated downward around the shaft 8a, and the bin 8 is
By tensioning the magnetic tape 2 by the magnetic tape 2, a constant tape tension suitable for recording/reproducing operations is generated.

The still playback method of this embodiment is achieved by configuring software means for the system controller 20 to perform the operations shown in the flowchart of FIG. 2 in the VTR with the tape running mechanism configured in this manner.

First, when a pause command is supplied from the operation signal generator 21 to the system controller 20 by the user's operation during the regeneration operation, the system controller 20 controls the capstan drive circuit 22 to stop the rotation of the capstan 9. At the same time, the reel drive circuit 24 and brake plunger drive circuit are controlled to stop the reel rotation operation, thereby stopping tape running. On the other hand, the rotary head drum 7 is driven as it is. That is, magnetic tape 2
A still operation is started in which the above specific tracks are continuously reproduced (Floo, FIOI). Note that at the start of the still operation, noise removal processing is executed as shown in step F102. This noise removal process is a process in which the capstan is slightly driven back and forth to search for a tape position on the still screen where there is no noise, and to set that position as the tape stop position.

When the noise removal process is completed and the tape stop position is determined, the system controller 20 causes the capstan drive circuit 22 to output, for example, a pulsed drive voltage to the capstan motor 23 for a very short time, causing the capstan 9 to move slightly. to move the magnetic tape 2 forward (in the direction of movement during playback) (F2O3). For example, the amount of movement is 2
It is set to a very small amount within the track width. At this time, the reel brake 27 is turned off, and the supply is stopped.
The magnetic tape 3 is in a free rotation state (a state in which the magnetic tape can be pulled out).

When the supply reel 3 is moved by a predetermined length, the reel brake is turned on to lock the supply reel 3 (F2O3). Then, by rotating the capstan 9 in the reverse direction, the magnetic tape 2 is moved backward (in the direction of movement during rewinding). The amount of movement is set to be the same as the amount of movement in step F103, and therefore, the magnetic tape 2 is restored to the tape position determined at the beginning of still playback (the tape position at the end of the noise removal process) (F2O3). At this time, since the supply reel 3 is locked and the tape movement is not wound onto the supply reel 3, the magnetic tape 2 is slightly loosened around the rotating head drum 7. Therefore, the tape tension is lowered, and even if still playback is continued for a long time in this state, accidents such as damage to the tape hardly occur.

After that, the still operation continues in this state, but the still operation ends based on other operation commands, etc. (F2O3)
.

By being controlled as described above by the system controller 20 as a still playback method, there is no need to provide a special tension control mechanism for the tension arm 8.
Since the tape tension during still playback can be lowered, long-time still playback is possible without complicating the mechanism. Furthermore, the tape position does not change during still playback, and there is no problem even when step playback or slow playback is performed after still playback.

For VTRs that have a built-in digital video memory, when the camera enters the still playback mode (after the noise removal process is finished), the playback video signal is imported into the video memory,
If the output of the still reproduced image is read out continuously from the video memory, it is possible to almost completely prevent noise from occurring on the still screen.

[Effects of the Invention] As explained above, the still playback method of the video signal playback device of the present invention stops the tape running, runs the tape slightly, and then locks the supply reel to restore the original state. Since the tape tension is loosened by returning it to the stop position, it is possible to control the tension during stills without installing a complicated tension control mechanism, and since the tape position does not change, good still playback operation can be achieved. There is an effect.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are diagrams of a tape running mechanism and a block diagram of a tape running control circuit of a VTR that can employ the still playback method of the present invention, and FIG. 2 is a flowchart showing an embodiment of the operation of the present invention. It is. 1 is a tape cassette, 2 is a magnetic tape, 3 is a supply reel, 7 is a rotating head drum, 8 is a tension arm, 9 is a capstan, IO is a pinch roller, 20 is a system controller, 22 is a capstan drive circuit, 24 is a reel The drive circuit 26 indicates a brake plunger drive circuit. Diagram

Claims (1)

[Claims] In a video signal playback device that uses a mechanical tension regulator to apply tape tension, when performing still playback during playback, the capstan is stopped to stop tape running, and then the supply reel is The capstan is driven without locking the rotation to cause the tape to travel slightly in the forward direction, and then the rotation of the supply reel is locked and the capstan is reversed to return the tape to its original stop position. A still playback method for a video signal playback device, characterized in that the video signal playback device returns to a point where it stops.