JPH02113461A - Reel driving device for tape recorder - Google Patents

Abstract

PURPOSE:To reduce the power consumption of the title recorder without giving any trouble to the speed control of a motor by turning on a light projecting element for detecting rotational speed only when the motor is rotated and timely turning off the element when the motor is stopped. CONSTITUTION:When a switch 1 is turned on, a tape reproducing command is inputted to a CPU 3 and transistors 8 and 9 are turned on by means of the output signal of the CPU 3. Then an LED 10 is caused to light. After the lapse of fixed time, the output of the CPU 3 is given to a transistor 14 and a motor 13 is driven. When a switch 2 is turned on thereafter, a tape stopping command is inputted to the CPU 3 and the output of a terminal 16 is stopped after fixed time elapses. The transistor 14 is turned off and the motor 13 is stopped. After the lapse of prescribed time, the transistor 9 is turned off and the LED 10 is lit out. Therefore, turning off of the LED is performed timely and the power consumption can be reduced without giving any troubles to the revolution of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a reel drive device for tape recorders that have recently become popular, such as portable VTRs (video tape recorders) and DATs (digital audio tape recorders). It is.

2. Description of the Related Art A device shown in FIG. 3 is currently mainly used as a drive device for controlling a reel shaft for rotating the tape itself and applying servo in a rotary head type tape recorder. In this figure, the tape is attached to the reel shaft 10.
1 rotates, a rotating plate 102 attached to the reel shaft 101 rotates. On this rotating plate 102, for example, a black radial striped pattern as shown in the figure is lined up at equal angular widths, and a light emitting element 103 such as an LED is brought close to this to generate light, and the reflected light is transferred to a phototransistor. The light is extracted by a light receiving element 104 such as the above.

In this way, the black and white stripes of the rotary plate 102 create a strength of the reflected light, and since a signal is extracted by the light receiving element 104 only when it is strong, a square wave pulse train is output from the waveform shaping circuit 105 as the plate rotates.

As the rotation speed becomes faster, this pulse width becomes shorter; as the rotation speed becomes slower, the width becomes longer, and the rotation speed of the reel is thereby detected.

Problems to be Solved by the Invention Recently, video tape recorders and digital audio tape recorders that can record or record outdoors have become popular in the market, but these devices use batteries as a power source. Therefore, a major challenge is how to extend the recording time by minimizing battery consumption. On the other hand, these devices used outdoors require the stability of the mechanism that drives the tape in order to ensure the image and sound quality recorded on the tape.
Particular attention has been paid to the stability of the motor rotation that the tape drive receiver has. For this reason, accurate rotation of the motor is the most important issue.

Now, regarding the light-emitting elements such as LEDs (or lamps) and the light-receiving elements to detect the above-mentioned reel rotational speed, current equipment performs operations such as tape playback and fast forwarding any time after the power is turned on. Therefore, the light emitting element 103 is lit continuously. For this reason, a current of 10 to 20 mA flows through the LED, etc. (or lamp current) at all times. Furthermore, in high-end equipment, in order to apply servo to both the supply reel and take-up reel, both reels are often provided with light-emitting elements for speed detection.

In such a case, the current of the LED is 20 to 40 mA, which is a considerable amount of current, and there is a problem in that it is a heavy burden on the battery.

To deal with this, of course, increasing the capacity of the battery will lengthen the time it takes for the battery to run out, but the larger the battery, the more space it will take to store it and the weight of the device. As the number of batteries increases, it becomes unsuitable for portable devices.Therefore, in order to miniaturize the device, it is a big challenge to make the battery smaller and to save power so that the battery life can be extended.

The present invention provides a technology to reduce power consumption while realizing motor speed control by energizing a light emitting element for detecting the rotational speed of a reel drive motor of a tape recorder only when necessary. This will be a major issue.

Means for Solving the Problems The present invention provides a reel driving motor for running a tape, a rotary plate connected to the motor and having a predetermined pattern,
A light projecting element that illuminates the rotating plate; a light receiving element that detects a light signal according to a pattern obtained from the rotating plate; and a speed control of the motor based on a cycle of the detection signal obtained from the light receiving element. a motor drive circuit; a light emitting element drive circuit that controls energization to the light emitting element; and after driving the light emitting element via the light emitting element driving circuit based on a drive signal of the motor, driving the motor. The control means is characterized in that it has a control means that gives an operation start signal to the circuit, and gives a stop signal to the motor drive circuit when the motor is stopped, and then gives a stop signal to the light projecting element drive circuit after a predetermined time. .

Embodiment Next, a first explanation of a reel driving device according to an embodiment of the present invention will be described.
This will be explained with reference to the figures.

Reference numeral 1 designates a switch for inputting, for example, a tape play command, and 2 a switch for inputting a tape stop command. These input signals are respectively applied to input terminals 17 and 18 of a control means, for example, a microcomputer 3. 4. 5.
8. 7 is a resistor, 8 is a transistor for LED power supply, 9
1 is a transistor for turning on and off the transistor 8, 10 is a light emitting element, for example, an LED, and 11 is an LED.
10 is a phototransistor that receives light; 12 is an amplifier; 13 is a motor for driving the reel; 14 is a transistor for driving the reel motor; 15 is a power supply circuit for the reel motor; the power supply voltage is determined by the speed detection pulse 27 taken out by the phototransistor. is now under control.

Next, the operation of this embodiment will be explained with reference to the time chart of FIG. 2.

First, when the switch 1 is turned on, the command pulse 19 for tape playback is sent to the microcomputer 3 as shown in FIG. 2(a).
is applied to the input terminal 17 of. Then, Figure 2(c)
As shown in the figure, the output signal 21 from the output terminal 15 of the CPU 3
is output and applied to the base of transistor 9 via resistor 6, turning on transistor 9. Therefore, the transistor 8 is turned on, and the power supply voltage of 10B is applied to the resistor 4.
applied to LEDlo through transistor 8;
o lights up. Furthermore, as shown in FIG. 2(d), an output signal 22 is output from the output terminal 16 of the microcomputer 3 after 12 hours. This signal is applied to transistor 14 via resistor 7, and motor 13 is driven. Then, as shown in FIG. 3, a pulse train corresponding to the rotational speed is obtained from the phototransistor 11 by the reflected light from the rotating plate, and is applied to the power supply circuit 15 via the amplifier 12. Since the power supply circuit 15 outputs a power supply voltage according to the pulse width of this pulse train, the rotational speed of the reel motor 13, that is, the rotational speed of the reel, is controlled.

Thereafter, when the switch 2 is turned on as shown in FIG. 2(b), the tape stop command 20 is sent to the microcomputer 18.
is applied to Then, after time T3, the output from the output terminal 16 of the microcomputer 3 is stopped, the transistor 14 is turned off, and the motor 13 is stopped. then 14
After a few seconds, the output 15 of the microcomputer 3 changes from H to L, and the transistor 9 connected through the resistor 6 turns off, and the power supply voltage is no longer supplied to the LEDlo, causing it to go out. The time difference between T and T4 is set because the LEDIO is always lit when the motor 13 is rotating.
Even when the motor 13 is in transition between ON and OFF, the LEDIO is completely turned on to prevent any abnormality from occurring in the operation of the motor.

Effects of the Invention As can be seen from the above embodiments, the light emitting element for rotation detection is turned on only when the motor is rotating, and the light emitting element is turned off when the motor is stopped, and the light is turned off in a timely manner. As a result, it is possible to prevent the motor from rotating without any trouble and to prevent the battery from consuming excess current, which is very effective in extending the battery life.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of a reel drive device for a tape recorder according to an embodiment of the present invention, FIG. 2 is a time chart showing its operation, and FIG. 3 is a diagram showing the main parts of a conventional reel drive device. It is. 1.2...Switch, 3...Microcomputer, 8,9.14...Transistor, 10...LED, 11...
・Photodiode, 12...Amplifier, 1
3...Motor, 15...Power circuit. Name of agent: Patent attorney Shigetaka Awano and 1 other person! &1
figure

Claims (1)

[Claims] (1) A reel driving motor that runs the tape, a rotary plate connected to the motor and having a predetermined pattern, a light projecting element that illuminates the rotary plate, and an optical signal according to the pattern obtained from the rotary plate. a motor drive circuit that controls the speed of the motor based on the cycle of a detection signal obtained from the light receiving element; a light emitting element drive circuit that controls energization of the light emitting element; After driving the light emitter through the light emitter drive circuit based on the motor drive signal, an operation start signal is given to the motor drive circuit, and when the motor is stopped, a stop signal is given to the motor drive circuit, and then a predetermined operation is performed. A reel drive device for a tape recorder, comprising: control means for giving a stop signal to the light projecting element drive circuit after a time period of .