JPS6158883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording device, and relates to the timing at which the tape stops when the head separates from the tape during the process from recording to stopping, the timing at which the bias supplied to the head stops, and the timing at which recording/playback is switched. By clearly configuring the timing at which the switch changes, it is possible to eliminate the occurrence of clicking sounds, magnetization of the head, and unerased data during the process from recording to stopping.

In general, in magnetic recording/reproducing devices, a mechanical mechanism is involved between the time when a stop command is issued and the tape is completely stopped, resulting in a time delay. On the other hand, since the stop command and the bias signal stop command are issued at the same time, when the recording operation is stopped, the tape may continue to run for a while even after the bias signal has stopped, resulting in the problem of unerased data. Ta.

The present invention has been made to eliminate such conventional drawbacks, and one embodiment thereof will be described below with reference to the drawings.

The storage circuit 1 is controlled by a recording command switch _S1 , a playback command switch _S2 , and a stop command switch _S3 .
When the motor is in a stopped state, its outputs a and b maintain a high level, ie, H.

Now, when the recording command switch _S1 is momentarily closed, the a output of the memory circuit 1 changes to a level lower than H, so-called L, the recording plunger drive circuit 2 operates, the recording plunger 3 is driven, and the recording/playback selector switch S is turned on. ₄ is switched from the playback state to the recording state.

Next, when the playback command switch _S2 is momentarily closed, the b output of the storage circuit 1 changes from H to L, the head plunger drive circuit 4 operates, the head plunger 5 is driven, and the tape and head are brought into contact. At the same time, the base current of the transistor Q ₁ supplied from the b output of the memory circuit 1 through the resistor R ₁ is cut off, and the transistor Q ₁ becomes non-conductive. At this time, press the recording/playback switch.
If _S4 is switched to the recording state, the voltage is applied from the power terminal +B supplied to the recording bias oscillation circuit 6 to the collector of the transistor _Q2 through the recording/playback switch _S4 , and is divided by the resistors _R2 and _R3 . A voltage is supplied from the emitter of the transistor _Q2 to the bias oscillation circuit 6, and the bias oscillation circuit 6 starts oscillating. Therefore, due to the contact between the tape and the head and the operation of the bias oscillation circuit 6, a state is reached in which recording can be performed on the tape. become.

Note that when the output b of the memory circuit 1 is H, the resistor R ₁
Since the base current flows through the transistor Q 1 through the transistor Q ₁ , this transistor Q ₁ is in a conducting state, and the base of the transistor Q ₂ is at ground potential, so the transistor Q ₂ is in a non-conducting state, and bias oscillation occurs. Circuit 6 has stopped oscillating.

Next, when the tape and the head are in contact, the bias oscillation circuit 6 is in operation, and the tape is ready to record, when the stop command switch _S3 is momentarily closed, the outputs a and b of the memory circuit 1 go from L to H at the same time. The head plunger 5 connected to the head plunger drive circuit 4 is released, and the tape and head are released simultaneously with the stop command, and a mechanical brake is applied to stop the tape. However, at this time, the tape stops after t ₀ from the stop command until the mechanical brake is applied. Also, since the output b of the memory circuit 1 becomes H, the transistor Q ₁ is connected to the resistor R ₁ ,
Due to the time constant of the capacitor _C1 , it becomes conductive at _t1 after the stop command, causing the transistor _Q2 to become non-conductive, thereby stopping the oscillation operation of the bias oscillation circuit 6.
Next, the a output of the memory circuit changes to H at the same time as the stop command, but it is released by the recording plunger drive circuit 2 after _t2 from the stop command, and the recording/playback selector switch is turned off.
The S ₄ is configured to switch from the recording state to the playback state.

FIG. 2 shows a specific circuit example of the recording plunger circuit 2. To explain this, the output a of the memory circuit 1 is connected to the other end of the resistor _R4 connected to the base of the transistor _Q3 . Ori,
When the output a of the memory circuit 1 is L, the transistor Q ₃
is made non-conductive and a base current is supplied to the base of the transistor _Q4 through the resistor _R5 to make this transistor _Q4 conductive.The power supply voltage +B is applied to the recording plunger 3 to attract it and the recording/playback selector switch S is turned on. Switch ₄ to the recording side. When the output a of the memory circuit 1 changes from L to H, the time constant of the resistor R ₄ and the capacitor C ₂ causes the transistor Q ₃ to conduct after t ₂ after the stop command, and lowers the base potential of the transistor Q ₄ to the ground potential. As a result, this transistor _Q4 becomes non-conductive, the recording plunger 3 is deactivated, and the recording/playback changeover switch _S4 is switched from the recording state to the playback state.

To explain these operations collectively using the timing chart shown in Fig. 3, at the same time as the stop command signal shown in Fig. 3 A is signaled, the a and b outputs of the recording circuit shown in Fig. 3 A and C rise from L to H. In synchronization with this, the head plunger 5 is deactivated as shown in Fig. 4(D), the tape and head are separated, and a mechanical brake is applied, so that the tape stops after t0 as shown in Fig. ₃ (E). In addition, as shown in FIG. 6F, the bias oscillation circuit 6 stops oscillating after a delay of time _t1 , so that even if the tape does not stop at the same time as the stop command, the erasing operation is sufficiently performed and no erasure is missed. Furthermore, as shown in FIG. 3G, the timing at which the recording/reproduction changeover switch _4S4 is switched to the reproduction side is delayed by a time _t2 - _t1 from the time when the bias oscillation is stopped, so that the head is not magnetized.

As explained above, in the process from the recording state to the stop state, the magnetic recording/reproducing apparatus of the present invention records data at a later time than the point at which the constant speed tape running means is stopped, the tape and the head are separated from each other, and the running of the tape is stopped. The bias oscillation circuit is stopped and the recording/playback switch is switched from the recording side to the playback side later than the time when the recording bias oscillation circuit stops operating, so that it is possible to reliably prevent the generation of click or shock sounds and the head's failure. It can eliminate magnetization and unerased tape, and the effect is great.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a magnetic recording/reproducing device according to an embodiment of the present invention, Fig. 2 is a circuit diagram of a head plunger drive circuit of the same device, and Fig. 3 A to G are timings for explaining the operation of the device. It's a chat. 1... Memory circuit, 2... Recording plunger drive circuit, 3... Recording plunger, 4... Head plunger drive circuit, 5... Head plunger, 6... Recording bias oscillation circuit, S ₁ ... Recording command. Switch, S ₂ ... Playback command switch, S ₃ ... Stop command switch, S ₄ ... Recording and playback selection switch,
R ₁ ~ _{R 5} ... Resistor, C ₁ , C ₂ ... Capacitor, Q ₁
~Q ₄ ...transistor.

Claims (1)

[Claims] 1. A constant speed tape running means for causing the magnetic tape to run at a constant speed by bringing the magnetic head and the magnetic tape into contact with each other, a control means for switching and controlling a recording/playback switching switch, and said recording/playback switching switch being switched to the recording side. a recording bias oscillator circuit that is operated by the magnetic head and supplies a magnetic head recording bias signal; a first delay circuit that delays the stop of the recording bias oscillator circuit by a certain period of time from the stop of the tape running;
A second delay circuit delays the switching of the recording/playback switch from the recording side to the playback side by the control means for a fixed period of time longer than the delay time of the first delay circuit, and when a stop operation is performed from the recording state, the tape runs at a constant speed. The recording bias oscillation circuit is deactivated later than the time when the recording bias oscillation circuit is stopped, the tape and head are separated from each other, and the tape stops running. A magnetic recording/reproducing device configured to be switched to the reproduction side.