JPS587479Y2 - Tape recorder timer recording circuit - Google Patents

Description

[Detailed explanation of the invention] This invention is based on the timer recording of a tape recorder.
To provide a timer recording circuit having a simple configuration, in which the solenoid of an auto-stop device is immediately energized when power is turned on from a timer, the pause mechanism is first unlocked, and the recording operation is automatically started. purpose.

To perform so-called timer recording on a cassette tape recorder, the tape recorder must be set in recording mode in advance and then peeled off.A pause mechanism is also provided to prevent the pinch roller from remaining pressed against the capstan for a long time. need to be set.

When the power is turned on by the timer in this way,
First, the pause state is released and recording begins, and when the recording ends and the end of the cassette tape is reached, the auto-stop device operates and the tape recorder returns to the stopped state.

Therefore, an auto-stop device is essential for this timer recording, and this device consists of a rotation detection means for detecting the stoppage of tape running, a drive circuit operated by the rotation detection means, and a solenoid energized by the drive circuit. The operation button is unlocked by a solenoid when the tape stops running.

Figure 1 is a circuit diagram of a conventional auto-stop circuit. Transistors Tr and Tr2 constitute a drive circuit for solenoid L, and the rotation detection signal passes through a rectifier circuit and a smoothing circuit to give ten potentials to point A. When there is no rotation detection signal, the drive circuit is turned off (non-conductive state), and when the rotation detection signal disappears, it is turned on (conductive state) and energizes the solenoid L.

When a power supply voltage is applied to such a circuit, a charging current instantly flows through capacitors C1 and C2 and brings point A to ten potentials, so a rotation detection signal is not yet generated immediately after the power is turned on. This prevents the auto-stop circuit from working while the device is not in use.

SL is a play switch, which is turned on only during recording or playback operations, and S2 is a pause switch, which is turned on when a pause operation is performed.

Therefore, if a pause operation is performed during recording or playback, the drive circuit will not be turned on because the switches S1 and 82 apply the dowel potential to point A through the resistor R1.

Further, since the play switch S1 is turned off during fast forwarding and rewinding, even if a pause operation is performed by mistake, no potential is applied to point A, so that the auto-stop circuit will not become inoperable.

The operation buttons of a cassette tape recorder, such as recording, playback, fast forward, and rewind, are usually locked by the same locking plate, but only the pause button uses a separate locking mechanism. In order to selectively release the pose locking mechanism in addition to the locking plate using the same solenoid, a solenoid operation switching mechanism is required.

As mentioned above, in order to perform timer recording on a cassette tape recorder, the recording and playback operation buttons are set in advance, as well as the pause button.When the timer is powered on, the pause button is first released using the solenoid. However, in the conventional circuit shown in the figure, when the power is turned on, ten potentials are immediately applied to point A, so the drive circuit is turned off, so solenoid L does not operate, and timer recording is disabled. It is impossible to do so.

FIG. 2 is a circuit diagram showing an embodiment of this invention, which allows timer recording to be performed with a simple configuration.

S3 is a pause switch, and in the recording or playback state, it is pushed to the contact side and the play switch S1 is also turned on, so when the power supply voltage is applied, the first capacitor C1 and the second capacitor Since a charging current instantaneously flows through the capacitor C2 and the point A becomes 10 potential, the drive circuit is kept on even before the rotation detection signal is generated.

The charge of capacitor C2 is transferred to resistor R2 and transistor Tr1.
is gradually discharged (forming a time constant circuit) through the base of and the resistor R3, but instead, the rectified output of the rotation detection signal is applied to point A, so the drive circuit continues to be in the off state.

Next, in the case of timer recording, since a pause button is also set in addition to the record and playback buttons, the pause switch S3 is switched to the contact a side, and when the power is turned on by the timer, a voltage of 10B is applied. Then, at point A, contact a1 of switch S3 resistor R1, play switch S1
Ten potentials are applied through the capacitor C.
Since the charge at point 2 is zero, charging of capacitor C2 is completed and the potential at point A reaches a value that turns off the drive circuit. ) will be required.

Therefore, during 1, the drive circuit is in a conductive state, energizes the solenoid, and unlocks the pause button, so that a predetermined recording operation is started.

Next, if you press the pause button during normal recording or playback, the pause switch S3 switches to contact a rather than the contact point, so the pause switch S3, resistor R□, and switch S0 are connected to point A. Since ten potentials are applied and the drive circuit is turned off, the tape recorder will not automatically stop.

As described above, this invention only adds one circuit switch to the conventional auto-stop circuit, and prevents the auto-stop circuit from operating even if a pause operation is performed during recording or playback, and also allows timer recording. In such a case, the switch has the advantage that the pause operation can be canceled and the recording operation can be started by immediately turning on the drive circuit and energizing the solenoid by turning on the power from the timer.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional auto-stop circuit, and FIG. 2 is a circuit diagram showing an embodiment of a timer recording circuit for a tape recorder according to the present invention. Trl) Tr2...Transistor constituting the solenoid drive circuit, Sl...Play switch, S3...Pause switch, R1, R2, R3
...Resistor, C1, C2...Capacitor, L...Solenoid.

Claims (1)

[Scope of utility model registration request] The tape recorder is equipped with a rotation detecting means for detecting the stoppage of tape running, a drive circuit operated by the rotation detecting means, and a solenoid energized by the drive circuit, and when the tape running stops, the tape recorder is placed in the stop E state. For the auto-stop circuit that is designed to return to normal state, a resistor is connected between the power supply and the input terminal of the drive circuit in the pause state, and a capacitor is connected in the non-pause state using a switch. A tape recorder characterized in that when power is applied, the drive circuit is kept in a conductive state for a certain period of time, and when the power is applied in a state other than pause, the drive circuit is instantly brought into a non-conductive state. Timer recording circuit.