JPS6117553Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording and reproducing apparatus that effectively prevents problems with the apparatus and the tape that occur when the tape becomes slack.

In a VTR (video tape recorder), in addition to causes of the tape drive system such as breakage of the tape winding drive belt, sticking of the magnetic tape due to dew on the drum surface, and changes over time, there are also The magnetic tape may sag due to causes such as instantaneous sagging of the magnetic tape at the time of rising. In the latter case, the slack in the tape is instantaneous in most cases, so there is often no need to set it to stop mode, but in the former case, it may lead to trouble with the device or the tape, so recording or playback is not necessary. In many cases, it is preferable to cancel the mode in which the tape runs, change it to stop mode, and then set it to the same mode again.

Therefore, it is preferable to detect whether the slack in the tape is instantaneous or to continue for a certain period of time, and to switch to the stop mode only when the slack in the tape continues for a certain period of time. Furthermore, if the tape slack occurs not only once but twice or more times, it is predicted that some serious trouble has occurred, so it is especially necessary to maintain the stop mode. expensive.

The present invention has been devised in consideration of the above-mentioned points, and includes a detection means for detecting that the tape has slackened for a certain period of time, and a detection means for counting the number of times that the tape has slackened for a certain period of time. and a control circuit that prohibits the operation of the tape running mode by detecting that the count value of the counter has reached a predetermined value. This relates to a recording/reproducing device. With this configuration, it is possible to efficiently detect that a serious trouble has occurred inside the recording/reproducing apparatus, and to effectively prevent damage to the apparatus and the tape.

An embodiment in which the present invention is applied to a VTR will be described below with reference to the drawings.

As shown in FIG. 1, the outputs of switch 1 which operates in conjunction with the fast forward button and switch 2 which operates in conjunction with the rewind button are supplied to an OR circuit 3, respectively. And the output of OR circuit 3 is AND gate 4
is supplied to one input terminal of the . The other input terminal of the AND gate 4 is supplied with the output of a flip-flop 6, which is set by the output of a switch 5 which is operated in conjunction with the playback button. Therefore, flip-flop 6
When the output is "1", the output pulse of the OR circuit 3 is supplied to the counter 7, and this counter 7 counts the output pulses of the switches 1 and 2. The output of the counter 7 is also supplied to a stop control circuit 8, which inhibits operations in modes in which the tape runs, such as recording and playback, and brings the VTR into a stopped state. ing. That is, the flip-flop 6 and counter 7 are reset by the output of the stop control circuit 8.

The output of yet another counter 9 is supplied to the stop control circuit 8 . The counter 9 is supplied with the output of a switch 10 of a magnetic tape slack detection sensor via a pulse width detection circuit 11. Note that the counter 9 is configured to be reset by a switching pulse from a switch 12 that operates in conjunction with the eject button.

Next, the protection operation by detecting queue and review operations achieved by the above configuration will be explained.
Queue or review operations are accomplished by pressing the fast forward or rewind button in playback mode. When the mode is switched to the playback mode, the flip-flop 6 is set by the output pulse of the switch 5, and its output becomes "1".
It is becoming. For this reason, gate 4 is open, and the switching pulses of switches 1 and 2 are OR
Counter 7 through circuit 3 and AND gate 4
It is in a state where it can be supplied to That is, when the fast forward button or the rewind button is pressed and switches 1 and 2 are closed during the playback mode, the number of times this operation is performed is counted by the counter 7.
It is counted by. The counter 7 is configured to count the number of operations of the fast forward button or the rewind button during a predetermined period of time, for example, 8 seconds.
A clock pulse as shown in FIG. 1 is supplied to the reset terminal via an OR circuit 13.
And this counter 7 counts, for example, 15 times in 8 seconds.
When the pulses from the AND gate 4 (see Figure 2B) are counted, the output of the counter 7 (see Figure 2C) changes from "0" to "1", the stop control circuit 8 is activated, and this output ( (see FIG. 2D) resets the flip-flop 6. Therefore, not only the inhibition of the queue or review mode but also the reproduction mode is canceled and the VTR is switched to the stop mode as shown in FIG. 2E.

Therefore, if the operation button to switch to queue or review mode is operated 15 times or more in a row over a certain period of time, this VTR will be switched to stop mode, and the drive plunger for queue or review will be switched to stop mode. No continuous load is applied,
Further, the driving power source does not generate heat and cause a malfunction. Furthermore, there is no delay in response speed during normal queue or review operations. In the above case, if the cue or review operation is performed a predetermined number of times, not only will the cue or review mode be prohibited, but the playback mode will also be canceled. It is also possible to only prohibit the operation.
Further, in the above case, the counter 7 counts the switching pulses of switches 1 and 2 during one period of the clock pulse (see Fig. 2A). The start point of the counting operation is arbitrarily changed based on the phase of the switching pulse, and when the counter 7 counts 15 pulses in the switching pulse count period starting from this start point, this output becomes "1". You can also do this.

Next, a protection operation based on detecting slack in the magnetic tape will be explained. When slack occurs in the magnetic tape, the switch 10 of the slack detection sensor closes and generates a pulse. If the width of this pulse is longer than the fixed period set by the pulse width detection circuit 11, the output of this pulse width detection circuit 11 is directly supplied to the stop control circuit 8, thereby
The mode in which the tape runs, such as recording or playback, is canceled and the VTR is switched to stop mode. Sag in the magnetic tape can occur not only due to the tape winding drive belt being cut, the magnetic tape sticking due to dew on the drum surface, changes over time in the running drive system, but also when switching to queue or review mode. Alternatively, the switch 10 may be closed due to a momentary slack of the magnetic tape at the time of these rises. Even in the latter case, it would be a problem if the stop control circuit 8 were activated, so a pulse width detection circuit 11 is provided so that the protection operation by detecting the slack of the magnetic tape is not performed during such normal operation. The pulse width detection circuit 11 is configured not to generate an output in response to instantaneous slack in the magnetic tape that is shorter than the set period.

Furthermore, the output of the pulse width detection circuit 11 is also supplied to a counter 9, where it is counted. Then, when the playback button is pressed again and the tape is in a mode such as recording or playback, the above-mentioned operation can be repeated again. produces output again. Therefore, as in the case described above, the VTR is again switched to the stop mode, and the output of the pulse width detection circuit 11 is again supplied to the counter 9, where it is counted. Note that when such an operation is repeated, for example, three times, and the counter 9 counts the output pulse of the pulse width detection circuit 11 three times, the output of the counter 9 changes to "1", and this state is maintained and stopped. The control circuit 8 is activated, thereby switching the VTR to the stop mode and maintaining that state. Note that counter 9
is configured such that it cannot be reset unless the eject button is pressed and the switch 12 is closed, or the power is turned off. Therefore, even if the playback button is pressed immediately, the VTR will not be switched to a mode in which the tape runs, such as recording or playback, and will remain in a stopped state regardless of whether or not the pulse width detection circuit 11 outputs. , VTRs are prohibited from operating in tape running modes such as recording and playback. In this way, the counter 9 is prevented from being reset unless the eject button is pressed or the power is turned off, and operations in the tape running mode such as recording and playback are prohibited three times from the pulse width detection circuit 11. When a pulse is emitted, it means that there is a serious problem, and in such a case it is necessary to remove the tape cassette and inspect the VTR.

Since the present invention is as described above, it is possible to efficiently detect the occurrence of a serious trouble inside the recording/reproducing device and effectively prevent damage to the device and the tape.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention applied to a VTR, and FIG. 1 is a circuit diagram of this embodiment.
FIG. 2 is a waveform diagram showing the operation of the circuit shown in FIG. 1, and the waveforms A to E each represent the waveform at the point with the corresponding symbol in FIG. 1. In addition, in the symbols used in the drawings, 1,
2, 5, 10, 12...switch, 7, 9... counter, 8... stop control circuit, 11... pulse width detection circuit.

Claims (1)

[Scope of utility model registration request] a detection means for detecting that the tape has slackened for a certain period of time; and a detection means for detecting that a count value of a counter to which the output of the detection means is added has reached a predetermined value in order to count the number of times the tape has slackened for a certain period of time. Accordingly, a recording/reproducing apparatus is characterized in that it is equipped with a control circuit that prohibits operation in a mode in which the tape runs.