JPS60202515A - Preventing device for video recording mistake - Google Patents

Abstract

PURPOSE:To prevent a video recording mistake due to a clogging fault by controlling the output of a video head. CONSTITUTION:A video head 2 has no clogging fault when the output of the head 2 is set at a sufficiently high level. Thus it is possible to proceed to the next video recording process directly. In case the output level of the head 2 is reduced, the head 2 is cleaned to solve the clogging problem. This can prevent the subsequent video recording mistakes. While the recording process is set back to the recorded mistake area after the head 2 is cleaned in case the output of the head 2 is reduced down to such a level to produce a video recording mistake. Thus the video recording/reproduction is possible with no mistake.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an error recording prevention device for preventing chair recording due to excessive clogging of a video head, and a device for preventing unrecorded portions when recording onto a magnetic medium. This is useful when applied to devices that can be so-called connected and manipulated.

<Prior Art> When recording video captured by a video camera onto a magnetic tape, multiple shots are recorded. In normal shooting mode, unrecorded portions occur between consecutively recorded shots due to the mechanism of the recording device.

Therefore, an apparatus that can perform so-called linage photography has been proposed.

FIG. 1 is an explanatory diagram conceptually showing this continuous shooting. In the figure, REC is recording mode, REV is reverse or reverse playback mode, PB is playback mode, E is recording end section,
P is a pause state (only the video head rotates and the video tape is stopped). S shown in Figure 2 is a stop of the video head (this stop S means a stop command, followed by an inertial rotation period; below "same") and owl indicate the overlapping parts, respectively.

As shown in Fig. 1, when one shot of recording RIC is performed on a magnetic tape, the video head is not stopped at the recording end point E and a series of operations are performed for a certain period of time (approximately 15 hours) from the recording end point E. ) After performing reverse or reverse playback REV, wait in the pause state and play for a certain period of time from the pause state PBt- and then record the subsequent shot RE
C, the time of the playback PR accompanying the start of recording is slightly shorter than the time of reverse or reverse playback REV, and the last part of the recording of the shot that has already been recorded and the beginning of the recording of the new shot that follows. Please overwrite the o in the figure.
vAt), this is a method to ensure that there are no unrecorded portions on the magnetic tape.

However, in magnetic recording and reproducing devices, clogging of the video head usually occurs easily. This clogging of the video head is caused by dust in the atmosphere, or magnetic powder generated when the magnetic head scans the magnetic tape, adhering to the periphery of the video head. Since it causes a lot of damage, it is necessary to take precautions.

Conventionally, only a technology has been disclosed that detects clogging during the reverse playback period and lights up a warning lamp. There is a need for a device that can detect unrecorded portions of a magnetic tape and enable re-recording.

<Object of the Invention> In view of the above-mentioned prior art, the present invention actively removes clogging in the video head, prevents the occurrence of recording gaps such as deterioration of image quality, and enables re-recording of already existing recording errors. The purpose of this invention is to provide a device for preventing chair recording.

Structure of the Invention> The structure of the present invention that achieves the above object is that in a device that rewinds a videotape for a certain period of time after the end of recording and performs splicing operation, the output level of the videotape is controlled via the video head during the rewinding period. a detection means for detecting the output level, a comparison means for determining whether the output level is high or low, and a cleaning means for cleaning the video head when the output level is lower than the first reference level. Further, another configuration of the present invention is
In an apparatus that rewinds a videotape for a certain period of time after recording is completed and performs continuous shooting), a detection means detects the output level of the videotape via a video head during the rewinding period, and detects the height of the output level. 11Wr+
A cleaning means for cleaning the video head when the output level is lower than the reference level of the bell station 1, and a second reference whose output level is lower than the first reference level. The present invention is characterized in that it has a reverse playback means for rewinding the erroneously recorded portion on the videotape when the level is further low.

<Effects of the Invention> With the above-described configuration, when the output level of the video head is sufficiently high, the video head is not clogged, and the next recording can be started without any change, and the output level of the video head is increased. If the level drops this much, perform head cleaning to clean the clogged holes.
It is possible to prevent future image errors. In addition, if the output level of the video head is low enough to cause a recording error, the head cleaning can be performed to return only the erroneously recorded portion that is formed in the post-read, allowing re-recording without recording waste. Become.

<Example> Here, an example of the present invention will be described with reference to FIGS. 2 to 4. FIG. 2 is a conceptual explanatory diagram of the continuous shooting method, and the same states as in FIG. 1 are given the same reference numerals and redundant explanations will be omitted. Here, REV indicates a reverse playback mode, and indicates a state in which the envelope of the signal recorded on the tape from the video head is detected.

Modes (1) to (I) in FIG. 2 mean the following.

Bad card (I) The video head is in good condition with no clogging. This means that the output level of the video head is the first reference value RF□(
(see Figure 3).

Bad (1)> The video head is about to become clogged, but it is not in a condition that would lead to recording errors.

This means that the output level of the video head is the first reference value RF,
(See FIG. 3), but this applies if it exceeds a second standard 1i1RF, which is separately determined.

<Sord (I)> When the video head becomes clogged and recording errors will occur if left unchecked. This corresponds to the case where the output level of the video head is equal to or less than the second reference value RF.

! ! As shown in Fig. 42, during the time of reverse playback REV from the recording end point E to Bose P in one shot recording REC, the output level of the video head is detected and the first
is compared with the reference value RF. As a result of this comparison, if the output level of the reverse playback RIM is equal to or higher than the standard value RF, there is no clogging tb in the video head, so mode (1)
), the process immediately moves to tPB and new recording RFC.

A second reference value RF, which is separately determined by lower than the reference value RF1 when the output level of the video head is in the mode ω),
When the video head exceeds the limit, it is assumed that the video head is about to become clogged, and head cleaning Cj is performed during the inertial rotation period when the video head is stopped SO in accordance with the cleaning command and command signal after the boy P. After head cleaning C1, there will be no recording scrapes due to clogging, so switch to mode (II).
PB and a new recording REC as shown in . In this case, since it is predicted that the image quality of the already recorded portion is not too bad, the recorded portion is left as it is.

The output level of the video head is the second reference value RF described above.
In the following cases, since the clogging tp of the video head has progressed steadily, head cleaning C is performed during the inertial rotation period when the video head is stopped S by the cleaning command after the pause P.
1 to remove any clogging. My wife in this clogged 9 state,
Since recording errors in the part that has already been recorded cannot be ignored, the tape position is further reversed and the recording error part (the part to the right of the part indicated by the arrow DEF in Fig. 2) is rewound, and then Dli' Perform fresh recording from position F. In this case, as shown by the concentrated line in mode (2) in Figure 2, it is possible to rewind only the portion of the recording error and perform the splicing operation at that position, but as shown in the dashed line in mode (2) in Figure 2 After rewinding all 17 stitches, the data may be played back to the DIF position and a new recording may be performed from that position.

In any case, it is possible to re-record the erroneously recorded portion, and at the same time, the normal recording of the portion leading to the successful image is saved.

FIG. 3 is a block diagram showing an actual example of the mistake recording device of the present invention. In the figure, 1 is a magnetic tape.

2 is a video head, 3 is a regenerative amplifier, 4 is a rectifier circuit, 5
．． 6 is a comparison circuit, 7 is a cleaning circuit, 8 is a continuous shooting circuit, 9 is an R-8 flip-flop circuit, 10 is a rewind playback circuit, and 11 is a hysteresis inverter. Here, an example of a two-head system is shown. The rectifier circuit 4 detects the video signal from the video head 2, extracts the envelope, and integrates it with an appropriate time constant to obtain a DC level output. Here, the envelope during reverse playback becomes condensed and there is a risk that it may be mistaken as clogging at a low level (less than the reference value RF1), so in order to equalize this envelope, the number of hours is determined, and for example, one field It is best to set the period to 1760 seconds. The comparator circuit 5 compares the output level of the rectifier circuit 4 with the reference value (reference voltage) RF of the Odate 1 described above, and outputs a signal to the linagi sensor circuit 8 when the output level of the rectifier circuit 4 is higher. do. This state is the mode (1) shown in FIG. 2 mentioned above. When the output level of the rectifier circuit 4 is smaller than the first reference value RF□, this level is inputted to the comparator circuit 6 until t.

The comparator circuit 6 compares the above level with the aforementioned second reference value RF.
, and when the output level is higher, a signal is outputted to the cleaning circuit 7 which performs the six-handed cleaning described above, and a signal is further outputted from the cleaning circuit 7 to the connecting circuit 8. This state is mode ω) shown in FIG. 2 mentioned above. Further, the output level of the rectifier circuit 4 is set to the second reference value RF.
.

In the following cases, this output level is output to the cleaning circuit 7 to perform the head cleaning described above.

Then, the R-87 rip 70 tube circuit 9 is placed in the set state and a signal is output to the rewind playback circuit 10. in this case,
The reset of the R-87 lip-flop IIM9 is performed by the rectifier circuit 4 via the inverter 11 having hysteresis characteristics.
This occurs when the output level of That is, it is reset when the recording chair area of the magnetic tape is rewound to a normal portion. After this, it becomes possible to re-record the portion where the recording error occurred. When rewinding by one shot as shown by the broken line in mode (1) in FIG. 2, it is necessary to provide a one-shot cue detection circuit in place of the hysteresis inverter 11. The above-mentioned state is established at node 7 (2) shown in FIG.

The head cleaning line, which is performed when a signal is input to the cleaning circuit 7 shown in FIG. 3, can be performed by the apparatus shown in FIG. 4, for example. In Fig. 4, 14 is a cylinder, and the cylinder 1 is attached to the cylinder on the side that rotates two times.
A video head protrudes by about 30 to 60 μm from the outer circumferential surface of 4, a magnetic tape 1 is wound around the cylinder 14tC by about 180 degrees to 220 degrees and runs at a constant speed, and 15 is a cleaning mechanism. The video head 2, which rotates together with the cylinder 14 in a loading state, is provided at a position where the magnetic tape 1 is not wound, that is, in a loaded state. The cleaning mechanism 15 includes a pad 16 that comes into contact with the rotating video head 2 to clean it.

A rotatable lever 17 that holds the pad 16, and a spring 18 that biases the lever 17 away from the cylinder 14 so that the pad 16 does not come into contact with the video head 2.

Holds a plunger 19 for rotating the lever 17 toward the cylinder 14 during the inertial rotation period of the video head 2, that is, the period when the video head 2 is rotating due to inertia after the video head 2 is driven, and these mechanisms. It is constituted by a substrate 20 for Therefore, in such a mechanism, when the plunger 19 is not operated, the lever 17 is separated from the cylinder 14 by the bias of the spring 18, so that the pad 16 does not come into contact with the rotating video head 2.

On the other hand, by actuating plunger 19.

Press the lever 17 against the bias of the spring 18.

The pad 16 is brought into contact with the rotating video head 2.

The pad 16 is made of a material that does not abrade the video head 2 and can sufficiently clean the video head 2. Such a material is preferably one that has close fibers (fiber mesh is sufficiently dense) so that it does not lint and is capable of adsorbing powder sufficiently. Examples include items such as Japanese cloth or high-quality Japanese paper. Furthermore, if necessary, a cleaning liquid for the head may be stored therein.

The operation of such a cleaning mechanism is as follows.

The cleaning circuit 7 (see FIG. 3) detects any output from the comparison circuit 6 and outputs it after reverse regeneration RIV.
The plunger 19 is actuated during the inertial rotation period of the video head 2 for a certain period of time after the video head stops S, and the pad 16
is brought into contact with the video head 2 to perform cleaning. After cleaning, a signal is output from the cleaning circuit 7 to the continuous shooting 9 circuit 8 or the R-S flip 70 tube circuit 9.

In the embodiment described above, the first reference value R is determined by the comparator circuit 5.6.
F1. Two stages of second reference value RFI, three modes,
(1) (n) (Although it is set to 1B, if the film is finer and has three or more layers, it will be possible to prevent the recording chair more accurately.

[Brief explanation of drawings]

FIG. 1 is a conceptual explanatory diagram of 9 methods for continuous shooting, FIGS. 2 to 4 are examples of chopsticks of the chair recording prevention device according to the present invention, and FIG. 2 is a conceptual explanatory diagram of nine continuous shooting methods. 3 is a circuit block diagram, and FIG. 4 is a perspective view of the cleaning mechanism. In the drawing, 2 is the video head. 4 is a rectifier circuit. 5.6 is a comparison circuit, 7 is a cleaning circuit. 8 is 9 circuits for continuous shooting and 1011 return playback circuits. 15 is a cleaning mechanism. REC is recording. E is the record i1uM completion point. REV is reverse playback. P is for pose. S is stopped. C1 is head cleaning. Patent applicant: Fuji Photo Film Co., Ltd. Patent attorney: Shibu Mitsuishi (and 1 other person) Figure 1 EC1 Figure 2 Mo'(I'Pa REC Figure 3-4)

Claims (2)

[Claims] (1) In a device that performs continuous shooting by rewinding a videotape for a certain period of time after the end of recording, there is a detection means for detecting the output level of the videotape via a video head during the rewinding period, and the level of the output level. What is claimed is: 1. A mistake recording prevention device comprising: a comparing means for determining the output level; and a cleaning means for cleaning the video head when the output level is lower than the first reference level. (2) In a device that rewinds the videotape for a certain period of time after the end of recording to perform splicing operations, a detection means for detecting the output level of the videotape via the video head during the rewinding period, and a detecting means for detecting the output level of the videotape through the video head during the rewinding period. a comparison means for determining, a cleaning means for cleaning the video head when the output level is lower than the first reference level, and a second reference level whose output level is lower than the first reference level. A mistake recording prevention device, characterized in that it has a reverse playback means for rewinding the skip-recorded portion on the videotape when the level is still low;