JPH02236848A - Magnetic recording part control method - Google Patents

Abstract

PURPOSE:To decrease tape damage and rotary head wearing by inverting a capstan by a prescribed angle in a rewinding direction in the vicinity of the consecutive recording starting position of a magnetic tape. CONSTITUTION:In a tension releasing mode, a capstan 6 is inverted by the prescribed angle while a magnetic tape 1 is being pressured by the capstan 6 and a pinch roller 7. Further an idler 9 is slightly separated from a take up reel 8, and it is set so as not to start the driving of a supply reel 3. Next, the magnetic tape 1 pinching pressure of the capstan 6 and the pinch roller 7 is decreased. In addition, a tension poll 4 is held at the intermediate position between a backward reproducing mode and a forward reproducing mode. Thus before the tape is made into a waiting state, the capstan is inverted by the prescribed angle, the tension of the magnetic tape is released, and the tape damage and rotary head wearing can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a magnetic recording section of a video camera or the like.

[Conventional technology]

When recording in a video table recorder or a video camera, it is required not only to simply record continuously on a magnetic tape, but also to temporarily stop the recording operation and then continue recording. In this case, if the track that was recorded just before and the track that will be newly recorded after the restart overlap or are significantly separated from each other, the recorded image will be distorted in that part.

Therefore, in the past, various efforts have been made to effectively perform such so-called continuous shooting.

FIG. 8 is an explanatory diagram of a conventional magnetic tape running state for performing such continuous shooting.

In FIG. 1A, on a magnetic tape 1, images and the like are magnetically recorded on tracks 2 formed diagonally in parallel. Note that track 2 shown by a solid line is a track that has already been recorded, and track 2' shown by a broken line is a track on which recording is subsequently performed by continuous shooting.

The magnetic tape 1 is conveyed in the direction of the arrow 1a, but in order to perform continuous shooting well, new recording should be started from the continuous shooting starting position A point on the magnetic tape 1 in the figure. In order to find this point A, for a certain period immediately before point A,
Recording is performed on the control track 2'' of the magnetic tape 1 by changing the duty ratio of the control pulse for the tape running servo.Therefore, after the magnetic tape 1 is temporarily stopped from the conveyance state during recording, continuous recording is performed. Extra length L
It is rewound by L, stops at a position where the duty ratio change point of the control pulse can be detected, and is held in a continuous shooting standby state.

In FIG. 8(b), the running state of the magnetic tape is indicated by arrows.

In other words, when recording is performed on the magnetic tape up to point A and the conveyance is stopped at point B, it is rewound by the splicing remaining length LL and then recorded at point C.
Stop at a point. The continuous shooting surplus length LL is set to a position slightly rewound from the position where the duty ratio change point of the control pulse can be detected. In other words, the duty ratio changing part of the control pulse is applied to the recorded track 2.
In order to accurately detect the boundary between the track 2' and the unrecorded track 2' and to synchronize with the next recording start operation, recording is performed immediately before recording stops, for example, for about 0.1 seconds. Therefore, the splicing surplus length LL is set to a length for rewinding the tape for approximately 1 second, and after the tape is restarted, the control pulses are read from the beginning and synchronization is performed.

Incidentally, as shown in FIG. 8(b), in reality, point D, which is slightly further along the magnetic tape transport than point C, is set as the position in the splicing standby state.

Specifically, the magnetic tape is conveyed from point C to point D for approximately 0.1 seconds, and is placed in a splicing standby state.

Then, when the magnetic tape transport is restarted from point D,
After about 0.9 seconds of transportation to point E, determination of the duty ratio of the control pulse is started.

The reason for performing such control is as follows.

FIG. 9 shows an explanatory diagram of a conventional method of controlling a magnetic recording section.

FIG. 9(a) shows a recording mode, that is, a state in which recording is in progress on a magnetic tape. The magnetic table l extends from the supply reel 3 through the tension ball 4 and along the rotary head 5 about 1
It is conveyed 80 degrees, sandwiched between a capstan 6 and a pinch roller 7, and wound onto a take-up reel 8.

In the figure, the supply reel 3 rotates in the direction of the arrow 3a in the recording mode, and in the reverse playback mode [FIG.
], it is rotated in the direction opposite to the arrow 3a in FIG. 3(a). Further, the tension ball 4 can take a position between the solid line and the broken line, and in FIG.
(b). In (c), the same figure (a)
It is configured to return in the opposite direction to the arrow 4a.

The rotary head 5 always rotates at a constant rotation in the direction of the arrow 5a, and the magnetic tape 1 is conveyed by guide rollers 10.11 so as to contact the side surface of the rotary head 5 by about 180 degrees. An arrow 1a indicates the transport direction of the magnetic tape 1 in this recording mode.

Further, as the capstan rotates, the pinch roller 7 rotates in the direction of the arrow 7a in the recording mode shown in FIG. )
In the reverse playback mode, it rotates in the opposite direction to the arrow 7a in FIG. Take-up reel 8 is shown in the same figure (
In the recording mode shown in a) and the forward playback mode shown in FIG. Rotate in the direction.

Note that the idler 9 rotates the take-up reel 8 and the supply reel 3 in directions corresponding to the respective modes through a transmission mechanism such as a gear (not shown).

Now, in the recording mode shown in FIG. 9(a), the magnetic tape 1 is supplied from the supply reel 3, a certain reverse tension is applied by the tension ball 4, recording is performed by the rotary head 5, and then the pinch roller 7 and a capstan 6, and is conveyed at a constant speed and wound onto a take-up reel 8.

Here, when the conveyance is stopped for continuous shooting, the 9th
As shown in Figure (b), the mode is switched to reverse playback mode and rewinding is performed. That is, the magnetic tape 1 is pulled out from the take-up reel 8 at a constant speed by the rotation of the capstan 6 and the pinch roller 7, is conveyed in the direction of the arrow 1a, passes in front of the rotary head 5, and is pulled out by the tension ball 4. It passes through the side and is wound onto the supply reel 3. In this case, in order to smoothly wind up the supply reel 3, the tension ball 4 is moved in the direction indicated by the arrow 4a to loosen the reverse tension.
moving in the direction. Further, the idler 9 is set to drive the sub reel 3.

In this way, the tape is rewound by the extra splicing length explained in Fig. 8, and once the tape shifts to normal playback mode as shown in Fig. 9 (C), it then enters the standby state as shown in Fig. 9 (d). .

That is, in the normal rotation reproduction mode, the magnetic tape 1 is driven for a very short time in the same state as in the recording mode shown in FIG. 9(a). Thereafter, the apparatus enters a standby state as shown in FIG. 2D, in which the pinching force on the magnetic tape 1 by the capstan 6 and the pinch roller is reduced. Further, the idler 9 is maintained in a state in which it does not transmit driving force to the take-up reel 8.

In this way, the forward rotation reproduction mode shown in FIG. 9(C) is sandwiched between the reverse reproduction mode shown in FIG. 9(b) and the standby state shown in FIG. 9(d) because the tape tension is relaxed. This is for the sake of That is, if the rewinding of the magnetic table 1 is stopped in the state shown in FIG. 9(b) and then immediately entered into a standby state, the tension applied to the magnetic tape 1 during rewinding is maintained as it is. .

Here, since the rotating head 5 is always rotating in the direction of the arrow 5a at a constant speed even in the standby state, if the tension of the magnetic tape 1 is high, the frictional force with the rotating head 5 increases, and the magnetic tape 1 This will damage the rotary head 5 and wear out the rotary head 5. Therefore, in the standby state, it is desirable to reduce the tension of the magnetic tape 1 as much as possible. For this,
Once the playback mode is returned to the normal rotation playback mode shown in FIG. 4C, the tension applied to the magnetic table 1, especially between the guide roll 10 and the take-up reel 8, is relaxed.

[Problem to be Solved by the Invention 1] As described above, in the continuous shooting standby state, it is preferable to weaken the tension of the magnetic tape 1 as much as possible to prevent damage to the magnetic tape 1 and wear of the rotary head 5. However, the same tension as during the normal rotation reproduction operation is applied to the magnetic tape 1 after passing through the normal rotation reproduction mode 5 shown in FIG. 9(C).
Shifts to standby state while joining almost as is, and furthermore,
Reverse tension etc. due to the tension ball 4 are also added. Although this tension is lower than the tension applied immediately after the reverse reproduction mode ends, it has not yet reached a negligible level, and further relaxation of the tension is required.

The present invention has been made with attention to the above points, and it alleviates the tension applied to the magnetic tape in the splicing standby state.
The object of the present invention is to provide a method of controlling a magnetic recording section that prevents tape damage and rotary head wear.

[Means to solve the problem]

A method for controlling a magnetic recording unit according to the present invention includes: after temporarily stopping a magnetic tape during recording from a conveying state, rewinding the magnetic tape by an amount of splicing surplus length, and then conveying the magnetic tape again after the rewinding is completed. The tape tension is relaxed by reversing the capstan at a predetermined angle in the direction of rewinding the magnetic tape. The present invention is characterized in that the pinching force of a pinch roller that pinches the magnetic tape is lowered to hold it in a continuous shooting standby state.

[Operation] According to the above method, the magnetic tape is stopped near the splicing start position as in the past, and before entering the splicing standby state, the capstan is reversed by a predetermined angle in the direction of rewinding the magnetic tape. Relieve tape tension. by this,
In particular, the tension applied to the magnetic tape can be significantly reduced in the area from the rotating head to the take-up reel. Furthermore, when the cab squeak is reversed by a predetermined angle, if both the supply reel and the take-up reel are kept in a non-driving state, the tape tension can be smoothly relaxed. Furthermore, by relaxing the reverse tension by the reverse tension applying means in the splicing standby state, the tension can be sufficiently relieved over the entire length of the magnetic tape.

[Example] Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

FIG. 1 is an explanatory diagram showing a method of controlling a magnetic recording section according to the present invention.

Before explaining FIG. 1, the differences between the method of the present invention and the conventional technique shown in FIG. 8 will be explained using FIG.

FIG. 2 is an explanatory diagram showing the running state of the magnetic tape according to the present invention, drawn in the same manner as FIG. 8(b).

First, the magnetic tape is conveyed to point B in recording mode and stopped there. Then, the mode shifts to the reverse playback mode, and rewinding is performed by the continuous shooting remaining length LL. When the rewinding is completed and the sheet stops at point C, the sheet shifts to normal rotation playback mode again and is conveyed to point D. Up to this point, the 8th
This is exactly the same operation as shown in Figure (b).

Here, in the method of the present invention, the apparatus further shifts to the tension relaxation mode, reverses the capstan by a predetermined angle in the direction of rewinding the magnetic tape, rewinds the tape by L, and enters a standby state. That is, when the standby state is entered at point F and the recording mode is instructed again, the tape is conveyed to point E, at which point detection of the change point in the duty ratio of the control pulse explained with reference to FIG. 8 is started.

Specifically, the reverse play mode is approximately 1.6 seconds. The normal rotation regeneration mode is executed for about 0.6 seconds, and the tension relaxation mode is executed for about 0.1 seconds, and after entering the regeneration mode from point F, it reaches point E about 1 second later, and detection of the point where the duty ratio of the control pulse changes starts. be done. When a change in duty ratio is detected for a predetermined period of time, the camera enters recording mode and performs accurate continuous shooting.

Returning again to FIG. 1, the method of the present invention will be explained in more detail.

1(a) to 1(f) illustrate a magnetic recording section having the same configuration as that shown in FIGS. 9(a) to 9(d).

That is, the magnetic tape 1 passes from the supply reel 3 through the tension ball 4, the rotating head 5, the capstan 6, and the pinch roller 7, and is wound onto the take-up reel 8. The supply reel 3 and take-up reel 8 are driven by an idler 9. Further, the tension ball 4 moves between the position indicated by the broken line and the position indicated by the solid line to apply reverse tension to the magnetic tape 1. Furthermore, magnetic tape 1
Along the guide roll 10 and the guide roll 11,
It is conveyed approximately 180 degrees along the side of the rotating head.

The reference numerals given in the drawings are all the same as in FIGS. 9(a) to 9(d), and redundant explanation will be omitted.

First, the recording section described above is operated in the recording mode as shown in FIG.
As shown in a), the magnetic tape 1 is transported in exactly the same manner as in FIG. 9(a). Then, in FIG. 1(b), when the reverse playback mode is entered, the magnetic table l is moved to the supply reel 3 in the same manner as shown in FIG. 9(b).
will be rewound. Thereafter, in the forward rotation reproduction mode shown in FIG. 1(C), the magnetic tape 1 is wound onto the pick-up reel 8 in the same manner as described in FIG. 9(C).

Next, in the method of the present invention, the mode shifts to the tension relaxation mode shown in FIG. 1(d). In this tension relieving mode, it is preferable that the idler 9 separates from the pick-up reel 8 and that both the supply reel 3 and the pick-up reel 8 are in a non-driven state. Then, while the capstan 6 and the pinch roller 7 continue to pinch the magnetic tape 1, the capstan 6 rotates in reverse so that it pushes the magnetic tape 1 back by a predetermined angle in the direction of the arrow 1a. As explained earlier, this reversal angle is
For example, the rotation angle is set to be approximately 0.1 seconds. Normally, the rotation of the capstan 6, the movement of the idler 9, the movement of the tension ball 4, etc. are synchronized with each other, and if the capstan 6 is reversed for more than a certain period of time, the idler 9
moves to a state in which the supply reel 3 is driven.

However, in this tension relaxation mode, the idler 9 is
The reel should be selected within a time such that it is slightly away from the take-up reel 8 and does not yet start driving the supply reel 3. Specifically, for example, the capstan 6 is driven several rotations or several tens of rotations. As a result, the magnetic tape 1 is rewound from the take-up reel 8, and since the supply reel 3 is not driven, the magnetic tape 1 is
The tension is further relaxed than in the state shown in Figure (C). If the standby state shown in FIG. 1(e) is entered from now on, it is possible to shift to the standby state with sufficiently lower tension than before.

The standby state shown in FIG. 1(e) is exactly the same as the standby state shown in FIG. 9(d), in which the capstan 6 and the pinch roller 7
The clamping force of the magnetic tape 1 is reduced.

By the way, when the state transitions from the state shown in FIG. 1(d) to the state shown in FIG. 1(e) and enters the standby state, the tension ball 4 shifts to a state similar to the normal rotation reproduction mode and applies reverse tension to the magnetic tape 1. I will add it. Therefore, even if the tension on the magnetic tape 1 is relaxed, the tension ball 4 causes the magnetic tape 1 to enter a standby state with the tension slightly increased.

Therefore, in the method of the present invention, as shown in FIG. 1(f), in this standby state, the tension ball 4 is held at an intermediate position between the reverse playback mode and the forward playback mode. You may. This state is called a reverse tension relaxation standby state. That is, in Fig. 1(f), ■
When the tension ball 4 is in the position , the reverse tension is at its maximum and this is the position in the normal rotation regeneration mode, and when it is in the position . In the reverse tension relaxation standby state, the tension ball 4 is held at the position 2 which is between 2 and 3.

The other states of the idler 9 and the states of the capstan 6 and the vinyl roller 7 are exactly the same as the standby state shown in FIG. 1(e).

In order to carry out the method of the present invention as explained above, the mechanism of the magnetic recording section is configured as follows.

FIG. 3 shows a block diagram of essential parts of a magnetic recording section suitable for carrying out the present invention.

In the figure, a control circuit 21 composed of a microprocessor or the like drives a capstan motor 23 via a capstan motor driver 22, and the rotation angle of this capstan motor 23 is detected by a rotation angle sensor 24. It is fed back to the control circuit 21. The control circuit 21 also controls the cam motor 2 via the cam driver 25.
6 is driven, and the rotation of the cam motor 26 is detected by the cam position sensor 27 to perform feedback control.

Here, the capstan motor 23 connects the capstan 6 to
The cam motor 26 is a motor that drives the cam 28. This cam 26 is configured to control the movements of the tension ball 4, pinch roller 7, and idler 9 shown in FIG. 1 by its rotation.

FIG. 4 shows a block diagram of essential parts explaining the operation of the cam.

In FIG. 4, the cam 28 is rotated by the arrow 26 by the rotation of the cam motor 26 and a gear 26a connected to its drive shaft.
Rotationally driven in direction b. The cam 28 is provided with a large number of through holes 28b for detecting the rotation angle, and the cam position sensor 27 detects the rotation angle of the cam 28 using a photocoupler 27a.

This cam 28 has, for example, three cam grooves 28a.
are formed, one cam groove 28a1 controls the operation of the pinch roller 7, and the other cam groove 2882 controls the operation of the idler 9.
The remaining cam groove 2883 controls the operation of the tension ball 4. The shape of each cam groove 28 and the movements of the pinch roller 7, idler 9, and tension ball 4 are shown in FIG.

FIG. 5(a) shows the movement of the pinch roller 7,
The cam groove 28a1 moves from the solid line position (■) to the positions (2) and (2) as the cam 28 rotates as shown in FIG.

Accordingly, the link mechanism 28c tracing the cam groove 2881 changes the position of the pinch roller 7 from ■ to ■. ■
Move it like this.

Similarly, FIG. 5(b) shows the movement of the idler 9. This idler 9 also moves due to the action of the link mechanism 28c as the cam groove 2882 moves in the order of ■, ■, ■.
Move the position of the idler 9 as ■, ■, ■. As a result, the state in which the idler 9 drives the take-up reel or the supply reel is selected.

FIG. 5(C) shows the operation of the tension ball 4. As the cam groove 2883 moves from ■ to ■ to ■, the tension ball 4 moves from ■ to ■ due to the action of the link mechanism 28c. ■
, ■, and the reverse tension is adjusted.

Incidentally, each of the link mechanisms 28c is actually connected to the cam groove 28.
It consists of a tracing part and several arms, cranks, etc. connected to it, but here, to simplify the explanation of its operation, it is represented as a single stick.

FIG. 6 shows a list of the states of the pinch roller 7, idler 9, and tension ball 4 in each mode.

That is, the recording mode of FIG. 1(a) and the first
In the normal rotation playback mode shown in Figure (C), the pinch roller 7
is in the position ■, where the clamping force is at its maximum. Further, the idler 9 is in the state (3) and is driving the take-up reel. Further, the tension ball 4 is in the state (■), and the reverse tension is medium.

In addition, in the reverse playback mode shown in FIG. 1(b), the pinch roller 7 is in the position ■ and the pinching force is large, and the idler 9 is in the position ■ to drive the supply reel and the tension ball 4 is in the position ■, but because the tape tension of the supply reel is high, the reverse tension is large.

Next, in the tension relaxation mode shown in FIG. 1(d), the pinch roller 7 is in the position ■ to increase the pinching pressure, the idler 9 is in the position ■ and is in a non-driving state, and the tension ball 4 is in the position ■, where the reverse tension is small.

Finally, in the reverse tension relaxation standby state shown in FIG. 5(f), the pinch roller 7 is at the position ■ and the pinching force is small, and the idler 9 is at the position ■ and is not driven. The tension ball 4 is in the position ■, where the reverse tension is minimal or zero.

In reality, in order to achieve such a state, the cam groove of the cam 28 shown in FIG. The cam 28 may be stopped at this position. FIG. 7 shows a block diagram of the capstan motor 23. As shown in FIG.

In FIG. 7, a rotary encoder 29 is connected to the rotation shaft of the capstan motor 23, and the rotation angle sensor 24 detects the rotation angle of the rotary encoder 29 using a photocoupler 24a. The rotary encoder 29 is provided with a large number of radial slits 29a, which are detected by the photocoupler 24a. This principle and rotation angle control method are well known in the past, and although a more specific explanation will be omitted, the rotation angle control shown in FIG. 1(d) is performed with the above configuration.

By configuring the magnetic recording section as described above, the method of the present invention explained in FIG. 1 can be carried out.

In addition, according to the conventional method shown in FIG. 8, as shown in FIG. 8(b), rewinding is performed by the splicing surplus length LL, the rewinding is stopped at point C, and the conveyance is continued to point D. If this occurs and the device enters a standby state, it is actually difficult to stop the device at the optimal position in front of the control pulse detection start position E due to the inertia of the motor drive. For this reason, conventionally, when the error due to the inertia is calculated and the conveyance of the magnetic tape is restarted from point D, it has been necessary to control the magnetic tape to be sent back and forth so as to correct the error ±X.

However, in the present invention, as shown in FIG.
Even if a stop position error of ±X occurs due to the inertia at a point, the magnetic tape is rewound by an amount greater than this X in the tension relaxation mode, and the magnetic tape shifts to a standby state.

Therefore, at point F, it is necessary to perform error correction only in ten directions, making control easier than in the case of correcting in + or one direction as in the past.

In addition, in the present invention, the drive and control of the tension ball 4, idler 9, capstan 6, pinch roller 7, etc. may be replaced with various conventionally well-known drive methods, and may not necessarily be performed all at once using a cam. There is no need to configure the control.

[Effect of the Invention 1] According to the method of the present invention explained above, the tension on the magnetic tape is relaxed by reversing the cab scan by a predetermined angle before entering the standby state, so the tension on the magnetic tape in the standby state is reduced compared to the conventional method. This can reduce damage to the magnetic tape and wear on the rotating head. Further, in the tension relaxation mode, by holding both the supply reel and the take-up reel in a non-driven state, tension relaxation can be achieved more effectively. Furthermore, by relaxing the reverse tension applied to the reverse tension applying means, the tension on the magnetic tape can be further reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the method for controlling the magnetic recording section of the present invention, FIG. 2 is an explanatory diagram of the magnetic tape running state according to the present invention, and FIGS. 3 and 4 are respectively diagrams of the present invention. A block diagram of the main parts of the magnetic recording section in which the method was implemented, FIG. 5(a) is an explanatory diagram of the operation of the pinch roller and cam, and FIG. 5(b) is an explanatory diagram of the operation of the idler and cam. Fig. 5 (C) is an explanatory diagram of the operation of the tension ball and cam, Fig. 6 is a list explaining the operation of the pinch roller, idler, and tension ball in each mode, and Fig. 7 is a magnetic FIG. 8 is a block diagram of the main part of the recording section, FIG. 8 is an explanatory diagram of the state of magnetic tape running in the conventional control method, and FIG. 9 is an explanatory diagram of the conventional control method of the magnetic recording section. 1... Magnetic tape, 3... Supply reel, 4...
- Tension ball, 5... Rotating head, 6... Capstan, 7... Pinch roller, 8... Take-up reel, 9... Idler. Figure R Figure Figure Figure Figure Figure Figure (a) Recording mode (b) Reverse playback mode (c) Forward playback mode (d) Standby state

Claims (1)

[Scope of Claims] 1. After temporarily stopping the magnetic tape during recording from the conveying state, rewinding the magnetic tape by the splicing surplus length, and returning the magnetic tape to the conveying state again after the completion of the rewinding. The capstan is reversed at a predetermined angle in the direction of rewinding the magnetic tape to relieve the tape tension, and after the tape tension is relieved, the capstan cooperates with the capstan to A control method for a magnetic recording unit, characterized in that the pinching force of a pinch roller that pinches the magnetic recording unit is reduced to maintain the continuous shooting standby state. 2. The magnetic reel according to claim 1, wherein both a supply reel and a take-up reel of the magnetic tape are held in a non-driven state when the capstan is reversed by a predetermined angle in a direction in which the magnetic tape is rewound. How to control the recording section. 3. The method of controlling a magnetic recording unit according to claim 1, further comprising relaxing the reverse tension applied to the magnetic tape by a reverse tension applying means in the splicing standby state.