JPH10241230A - Video cassette deck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a slow reproducing picture. SOLUTION: A magnetic tape 11 is traveled in both forward and reverse directions by a tape traveling system 20. Tension is applied to the magnetic system 11, and also the tension is changed whenever the magnetic tape 11 is changed in its travel in the forward direction or in the reverse direction by a tension changeover mechanism 30. When the traveling direction of the magnetic tape 11 is changed under a slow reproducing mode, an instruction of a high speed frame feed of more than one frame is given to the tape traveling system 20 by a traveling control part 40. By preventing the slack in the magnetic tape 11 due to a sudden change in tape tension at the time of changing the traveling directions of the magnetic tape 11 under the slow reproducing mode, deterioration of the picture quality is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type video cassette deck for reproducing, recording and reproducing video signals using a rotary magnetic head, and more particularly, to a magnetic tape in a loaded cassette. And a tension switching mechanism for switching the tape tension between when the magnetic tape runs in the forward direction and when the magnetic tape runs in the reverse direction. Video cassette deck.

[0002]

2. Description of the Related Art A helical scan type video cassette deck for reproducing, recording and reproducing video signals by using a rotary magnetic head usually uses a magnetic tape in a cassette loaded in the deck at a speed different from a normal speed. It has a slow playback mode for running at low speed for playback. In this slow playback mode, playback can be performed not only when the magnetic tape is traveling in the forward direction, but also when the magnetic tape is traveling in the reverse direction. Switching of tape tension is often performed.

The purpose of switching the tape tension is to add an appropriate back tension at the time of slow forward rotation and to reduce the load of the back tension at the time of slow reverse rotation as compared with the forward rotation. The tape tension is added on the side, and the tension is increased for forward running and reduced for reverse running.

[0004]

However, in a video cassette deck provided with such a tape tension switching mechanism, if the tape running direction is switched during slow playback, the tape tension changes rapidly with the switching. , There is a problem that the slow reproduction image is largely disturbed.

That is, when the tape running direction is switched in the slow reproduction mode, the tape tension changes suddenly with the switching operation. Specifically, when adding tape tension at the entry side of the cylinder,
When the running direction of the magnetic tape is switched from the forward direction to the reverse direction, the tension on the entry side rapidly changes from large to small.
Due to the sudden decrease in tension at the entry side, the magnetic tape temporarily slackened.As a result, the magnetic tape was lifted from the cylinder surface, and the envelope was lost. It becomes.

The present invention has been made in view of such circumstances, and in spite of switching the tape tension depending on the tape running direction in the slow playback mode, it is possible to suppress the disturbance of the image due to the switching of the tension and to reduce the speed of the tape. An object of the present invention is to provide a video cassette deck for stabilizing reproduced images.

[0007]

SUMMARY OF THE INVENTION A video cassette deck according to the present invention is a video cassette deck provided with a slow playback mode in which a magnetic tape in a loaded cassette runs at a low speed different from a normal speed and is played back. A tape running system for running the magnetic tape in both forward and reverse directions, and a tension switch for applying a tension to the magnetic tape and switching the tape tension between when the magnetic tape runs in the normal direction and when the magnetic tape runs in the reverse direction. And a traveling control unit for instructing the tape traveling system to feed two or more frames at a high speed when the tape traveling direction is switched in the slow reproduction mode.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a tape running path showing a schematic configuration of a video cassette deck according to an embodiment of the present invention, and FIG. 2 is a flowchart showing a control operation of the video cassette deck according to the embodiment of the present invention.

The video cassette deck according to the embodiment of the present invention has a slow reproduction mode in which the magnetic tape 11 in the loaded cassette 10 is run at a low speed different from the normal speed and reproduced. As hardware, a tape running system 20 for running the magnetic tape 11 in both forward and reverse directions, and a tape running system for applying tension to the magnetic tape 11 and running the magnetic tape 11 in the forward direction and in the reverse direction. A tension switching mechanism 30 for switching the tension, and a traveling control unit 4 for instructing the tape traveling system 20 to feed two or more frames at a high speed when the tape traveling direction is switched in the slow playback mode.
0.

The tape running system 20 includes a pair of roller units 22, 22 arranged on both sides of a cylinder 21 having a magnetic head on the outer peripheral surface thereof to bring the magnetic tape 11 into contact with the outer peripheral surface of the cylinder 21. , 22 and a capstan 23 and a pinch roller 24 for running the magnetic tape 11 in both forward and reverse directions, and the magnetic tape 11
It has driven gears 25 and 25 and an active gear 26 for driving the reels in the cassette 10 to take up in the zero.

When the cassette 10 is loaded at a predetermined position, the pair of roller units 22 and 22 move from the initial position to the operating position to move the magnetic tape 11 to the cylinder 21.
Is brought into contact with the outer peripheral surface in an Ω shape. Also, capstan 23
And the pinch roller 24, the magnetic tape 11 is sandwiched.
When the capstan 23 rotates forward in this state, the magnetic tape 11 travels in the forward direction. In synchronization with this, the active gear 26 meshes with and drives the driven gear 25 on the take-up side, so that the magnetic tape 11 is wound on the take-up side reel.

When running the magnetic tape 11 in the reverse direction, the capstan 23 is reversed. The active gear 26
Meshes with and drives the driven gear 25 on the supply side.

In the slow reproduction mode, the magnetic tape 11 runs in both the forward and reverse directions at a speed lower than the normal speed.

The tension switching mechanism 30 has a first lever 31 disposed on the entry side of the cylinder 21. The first lever 31 has a post 32 at the distal end, and the base is pulled by the spring 33 to elastically press the post 32 against the magnetic tape 11 from the inside to the outside to add tension to the magnetic tape 11. I do. The spring 33
Is connected to one end of the second lever 34.
The other end of the second lever 34 is connected to a third
It is connected to a lever 36.

When the running direction of the magnetic tape 11 is switched from the forward direction to the reverse direction, the third lever 36 rotates in a direction in which the tip of the third lever 36 moves downward in the figure. Thereby, the pulling force by the spring 33 is weakened, and the tension applied to the magnetic tape 11 is reduced. At this time, the post 32 moves inward, which causes the magnetic tape 11 to be loosened as indicated by the broken line in the figure, as described above.

When the running direction of the magnetic tape 11 is switched from the reverse direction to the forward direction, the third lever 36 rotates in the reverse direction and the pulling force of the spring 33 increases, so that the magnetic tape 11 is added to the magnetic tape 11. The tension applied is increased.

The traveling control unit 40 is configured in a system computer of the video cassette deck. The operation will be described based on the flowchart of FIG.

In step S1, it is determined whether or not the current mode is the slow reproduction mode. If the mode is not the slow reproduction mode, the process proceeds to step S4, and the tape traveling system 20 is instructed to feed one frame forward. If the current mode is the slow playback mode, it is determined in step S2 whether or not a forward / reverse switching instruction of the tape running direction has been issued. If the forward / reverse switching instruction of the tape running direction has not been issued, the process proceeds to step S4, and the tape running system 20 is instructed to feed one frame. When the forward / reverse switching instruction of the tape running direction is issued, at step S3, 2
High-speed frame advance of frames or more is instructed to the tape traveling system 20.

As a result, at the moment when the tape running direction is switched from the forward direction to the reverse direction in the slow reproduction mode, high-speed frame feeding of two or more frames is executed. As previously mentioned,
At this moment, the pulling force by the spring 33 decreases,
The post 32 moves inward due to a sudden decrease in the tension applied to the magnetic tape 11, but the high-speed frame feed of two or more frames is executed in accordance with this timing, and the magnetic tape 11 becomes slack. Is prevented. Therefore, at the time of this switching, the phenomenon that the magnetic tape 11 rises from the cylinder 21 is avoided, and a stable slow reproduction image is obtained. Specifically, the number of frames to be transferred in the high-speed frame feeding is appropriately selected so that the slack of the magnetic tape 11 caused by the tension switching is absorbed.

When the tape running direction is switched from the reverse direction to the forward direction in the slow reproduction mode, high-speed frame feeding of two or more frames is executed.
Since no slack occurs, a stable slow reproduction image can be obtained regardless of the presence or absence of this high-speed frame feed. This high-speed frame feed temporarily increases the tape tension, which is absorbed by the movement of the post 32 in the tension switching mechanism 30.

As in the present embodiment, only when the tape running direction is switched from the forward direction to the reverse direction, the magnetic tape 1
If 1 is loose, high-speed frame advance of two or more frames may be executed only at the time of this switching. Similarly, when the magnetic tape 11 is loosened by the reverse switching, high-speed frame feeding of two or more frames may be executed only at the time of this switching.

[0022]

As described above, the video cassette deck according to the present invention is provided with the slow playback mode in which the magnetic tape in the loaded cassette is run at a low speed different from the normal speed and played back. In a video cassette deck equipped with a tension switching mechanism that switches the tape tension between when the tape runs in the forward direction and when the tape runs in the reverse direction, when the tape running direction is switched in the slow playback mode, two frames or more In this configuration, the slack of the magnetic tape caused by the change in the tape tension due to the switching of the tape running direction can be absorbed. Therefore, although the tape tension is switched according to the tape running direction in the slow playback mode, the disturbance of the image due to the switching of the tension can be suppressed, and the slow playback image can be stabilized.

[Brief description of the drawings]

FIG. 1 is a plan view of a tape running path showing a schematic configuration of a video cassette deck according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control operation of the video cassette deck according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 cassette 11 magnetic tape 20 tape running system 21 cylinder 22 roller unit 23 capstan 24 pinch roller 30 tension switching mechanism 31 first lever 32 post 33, 35 spring 34 second lever 36 third lever

Claims (1)

[Claims] 1. A tape running system for running a magnetic tape in a forward / reverse direction in a video cassette deck provided with a slow playback mode in which a magnetic tape in a loaded cassette is run at a low speed different from a normal speed and played. And a tension switching mechanism for switching the tape tension between when the magnetic tape is tensioned and when the magnetic tape is run in the forward direction and when the magnetic tape is run in the reverse direction, and the tape running direction is switched in the slow playback mode. And a running control unit for instructing the tape running system to feed two or more frames at a high speed.