JPS5941669Y2 - Automatic stop device in magnetic recording or reproducing equipment - Google Patents

Description

[Detailed description of the invention] The invention is placed in a device for recording video signals on a recording medium,
By detecting that the input video signal has disappeared, even momentarily, and interrupting the operation of the device and continuing the stopped state thereafter, it is possible to prevent the occurrence of unrecorded portions of the video signal on the recording medium. An object of the present invention is to provide an automatic stop device for preventing a video signal from being continuously recorded.

In businesses that use recording devices to produce recording tapes, various measures are taken to ensure that recording tapes with non-recorded portions do not become finished products.

As a first method, a recording signal is applied to the recording apparatus and also to a monitoring monitor receiver, and the monitor screen is monitored during recording.

According to this method, it is possible to confirm that the recording input signal has disappeared temporarily or continuously, but there is a problem that it is not possible to sufficiently detect a very short interruption of one second or less.

In order to solve this problem, it is necessary to reproduce the data after recording is completed and check whether there is any unrecorded portion.

This test requires running the tape at the same speed or slower than that during recording.

For this reason, there is a drawback that the inspection cost occupies a large proportion of the production cost of the recording tape.

Here, the reasons for the interruption of the recording signal are (1)
When recording the playback signal from the parent playback device, a.
(It may recover after a few seconds) (b) If an abnormality occurs in the power supply or circuit of the main player, (C) If an abnormality occurs in the connector or cable between the main player and the recorder, (2) TV receiver. If the signal source is: a. If there is an abnormality in the TV broadcasting station and broadcast waves are no longer being sent, b. If an abnormality occurs in the power supply or circuit inside the TV receiver, c. If an abnormality occurs in the connection to the TV receiver recorder. If so, etc.

The present invention is configured to detect momentary interruptions in the recording signal to the recording device due to the various abnormalities mentioned above, and to stop the recording operation of the recording device, so that a recording tape having no recorded portion is not created. An embodiment thereof will be described below with reference to the drawings.

First, let's talk about the configuration and operation of one example of a magnetic recording device.
This will be explained with figures.

When the recording device 1 is in the stop mode, when a recording push button (not shown) is pressed, the romeding motor 2 and the main motor 3 are started, and a loading operation is performed.

In the loading operation, first, the arms 4 and 5 rotate clockwise to the position shown in the figure, and the guide ball 6 loads the magnetic tape γ.
is pulled out from the cassette 81A so as to form a substantially triangular tape loop γa, and then the rotary ring 9 arranged in an inclined manner rotates clockwise to the position shown in the figure, and the leading guide pin 10 pulls out the tape loop γa. When the tape γ is inserted into the guide drum 11 and removed, the tape γ is locked and the guide drum 11 is removed.
This is done by routing the wire around the

When the ring 9 rotates to the position shown, the pinch roller 12
The capstan 134 is crimped, and the apparatus 1 is converted to the recording mode shown.

The tape path in the recording mode is as shown by the solid line in the figure, and the magnetic tape T pulled out from the supply side tape winding body 14a in the cassette 8 attaches its magnetic surface to the erasing magnetic head 15. The image is then erased over its entire width by a rotating magnetic head (not shown) attached spirally to the circumferential surface of the guide drum 11 over a predetermined angular range and rotated at high speed by the main motor 3. The signal is recorded.

Next, the magnetic tape T is attached to an audio control magnetic head 16 to record audio and control signals, and then a capstan 13 driven by the main motor 3
It is pinched and driven by the pinch roller 12.

The tape T sent out by the clamping part is almost reversed in its traveling direction by the guide pin 10, and guided to guide balls 17a and 1rb-17c which are set up on the rotating ring 9.
After passing through the further guide ball 6, the tape is wound onto a winding-side tape winding body 14b to which a rotational force is applied in the tape winding direction.

Next, an embodiment of the automatic stop device of the present invention incorporated in the recording apparatus 1 will be described with reference to the circuit diagram shown in FIG.

In the stop mode mode, the commercial voltage is converted to a DC voltage of a predetermined voltage via a rectifier circuit consisting of transformer T1 and diodes D1 to D4, and is then converted to a DC voltage of a predetermined voltage via a smoothing capacitor C1 and a power supply stabilizing circuit 20 shown enclosed by a broken line. The signal is supplied to a circuit 21 for detecting the disappearance of an input signal, which is a main part of the device, and each circuit becomes operational.

In the power supply stabilizing circuit 20, the control transistor Tr
, J and error amplification transistor Tr1 are connected in a Turlington manner.

The reference voltage Zener diode D is the transistor Tr□
It is connected to the base.

R1 is a bias resistor, and C2 is a bypass capacitor.

The control transistor Tr3 has its collector side connected to the resistor R2.
The base of the transistor Tr1 is connected to the collector side of the transistor Tr4 of the detection circuit 21 through a diode D6 whose base side is connected in the opposite direction.

Further, the detection circuit 21 is supplied with the above-mentioned DC voltage and is in an operating mode.

The video signal that enters the input terminal 22 is controlled by automatic gain control (AG).
C) The signal is applied to the circuit 23, the signal level of which is controlled to be constant, and is applied to the recording device 1 via the output terminal 24, as well as to the synchronizing signal separation circuit 25.

The horizontal or vertical synchronizing signal separated by the circuit 25 is amplified by the synchronizing signal amplifying circuit 26 and then connected to the capacitor C3.
is clamped by diode D and capacitor C4, and the voltage drop across resistor R3 is applied to transistor T.
applied to the base of transistor T r 4
is turned on.

Therefore, when a video signal is input to the terminal 22, the terminal 2γ
The +12V voltage applied to resistor R6, transistor T
r4 and grounded via resistor R6.

Therefore, the collector potential of the transistor Tr becomes low, and the base potential of the transistor Tr3 of the circuit 20 is also made low, and since the transistor Tr3 is turned off, the base of the transistor Tr4 is connected to the ground. will be released.

As a result, in circuit 20#, the DC current supplied from the rectifier side passes through the bias resistor R1 to the transistor T.
It is applied as a bias voltage to the base of r 1 to turn on transistor Tr □ and similarly turn on transistor Tr 2 .

Therefore, the circuit 20 operates and a high potential current is output to the output line A.

In the above embodiment, when the recording leg button (not shown) is pressed, switches SW1 and SW2 are closed in conjunction with each other, and recording mode relay Re and plunger 30 are activated.

When the relay Re is activated, the switch SW
2 is closed and the main motor 3 is driven by the commercial power source.

The switches SW1 and SW2 are held in a closed state by the plunger 30 (as desired).

Moreover, the braking force on the supply side reel disk is released by the operation of the plunger 30.

Further, the loading motor 2 is activated by the push button f, and the loading operation is performed as described above, and the recording operation is started in the manner shown in FIG.

Next, a description will be given of an operation for aborting and stopping the recording operation of the apparatus when the input video signal is interrupted for some reason during the recording operation.

Here, when detecting that the input of the video signal to be recorded has ceased, it is sufficient to detect one component included in the composite video signal.

However, when this negative component is used as a video signal, the average level value varies greatly depending on the content of the screen. For example, if the entire screen is dark, the level value will be low, and this will cause the detection device to operate and There are cases where the loss of the signal is mistakenly recognized.

For this reason, in the device of the present invention, a horizontal or vertical synchronization signal unrelated to the screen content is employed as the above-mentioned component.

When the input video signal disappears, the output signal from the synchronization signal separation circuit 25, that is, the synchronization signal amplification circuit 26 disappears.
The voltage across resistor R8 drops.

Therefore, the base voltage of transistor Tr4 drops,
Correspondingly, this collector voltage increases.

This increased collector voltage is applied to the base of the transistor Tr3 via the diode D6, making the transistor Tr5 conductive.

When the transistor Tr3 turns on, the transistor Tr3 turns on.
The base voltage of the output line A is grounded through the resistor R2 and the collector-emitter of the transistor Tr3, the transistor Tr1 and the transistor Tr2 are both turned off, the circuit 20 is in a non-operating state, and the potential of the output line A is The voltage becomes zero, and the relay Re and the plunger 30 are de-energized and are both in a non-operating state.

When the relay Re becomes inactive, the switch SW is activated and the rotation of the main motor 3 is stopped.

Furthermore, when the plunger 30 is demagnetized, a braking force is applied to the supply reel disk, and the pinch roller 12 is released from being pressed against the capstan 13.

Therefore, the magnetic tape immediately stops running while being loaded in a tape path similar to the tape path shown in FIG. Stop.

The above operation is performed instantaneously. Further, when the plunger 30 is demagnetized, the switches SW1 and SW2, which have been closed by the push button operation, are opened in conjunction with each other.

Therefore, even if the input video signal enters again after it has disappeared and the circuit 20 is placed in the operating mode, both the relay Re and the plunger 30 remain in the non-operating mode.

This completely prevents video signals from being recorded leaving unrecorded portions on the magnetic tape.

It is also possible to configure a relay to be activated and open the commercial AC power supply circuit by the operation in response to the disappearance of the input signal of the detection circuit 21.

As mentioned above, according to the automatic stop device for the magnetic recording device according to the present invention, when the input video signal disappears even instantaneously during the operation of recording the video signal on the recording medium, the operation of the recording device is stopped. Since the structure is configured so that the stopped state continues even when the signal is interrupted and the signal is recovered thereafter, there is no unrecorded part on the recording tape, there is no need to use a monitor for monitoring during recording, and furthermore, the recording operation is The process of inspecting the recording medium for the presence or absence of non-recorded portions after completion of the process is no longer necessary, and the inspection cost can be almost eliminated.Furthermore, it is possible to detect interruptions in the input video signal by detecting the disappearance of a separate synchronization signal of the video signal. Since it is configured to perform detection, it has the advantage that the above-mentioned interruption can be detected stably without being affected by fluctuations in the video signal level.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the recording operation mode of an example of a magnetic recording device to which the automatic stop device of the present invention is applied, and FIG. 2 is a circuit diagram of one embodiment of the automatic stop device of the present invention. . 1... Recording device, 2... Loading motor, 3... Main motor, T...
・Magnetic tape, 8...Cassette, 11...
... Guide drum, 12 ... Pinter roller, 1
3...capstan, 15...magnetic head for erasure, 16...magnetic head for audio control, 20...power stabilization circuit, 21
...detection circuit, 25 ... synchronization signal separation circuit, 26 ... synchronization signal amplification circuit, 30 ...
... Plunger, Re... Recording mode relay.

Claims (1)

[Scope of utility model registration request] A device for recording a video signal on a recording medium (herein, a switch that puts the device in a recording mode when closed and puts the device in a stop mode when opened, and a synchronization signal separation circuit that separates a synchronization signal from an input video signal; The switch control circuit detects the disappearance of the synchronization signal from the synchronization signal separation circuit, opens the previously closed switch, and does not operate even if the input signal is restored, thereby interrupting the input video signal. An automatic stop device for a magnetic recording device, wherein the device is placed in a stop mode, and the device remains in the stop mode even if the video signal is input again.