JPS58147863A - Control system for head position of magnetic reproducing device - Google Patents

Abstract

PURPOSE:To shorten the positioning time of a head and to improve operability, by driving a motor at a high voltage up to before a target position of the head and driving the motor at a low voltage thereafter, and thus braking the motor excellently. CONSTITUTION:When a play switch PLAY is turned on, outputs of output lines 21 and 22 are held at L and H respectively and the motor rotates normally through a driving circuit 20 to allow the head to start moving. The output of an output line 27 is at L and a transistor (TR) 26 is also turned off, so the motor 1 rotates at a high speed at a 11.3V high voltage. In this case, a reflecting plate 17 also rotates and right after a position STOP, the photodetecting element of a photoreflector 18 receives light from the reflecting plate 17 to generate an output H. The reflecting plate 17 is rugged, so a control circuit 12 detects arrival at a position PAUSE to hold the output of the output line 27 at H. Then, the TR26 turns on and the output of a fixed voltage circuit 24 drops to 7V and the motor 1 rotates while having inertia reduced by low-voltage drive.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a head position control system for a magnetic reproducing apparatus such as a IIIjFi tape recorder.

For erasing magnetic playback devices such as tail recorders,
Recording and playback heads are driven by motors. In figure 1, 1 is a motor, 2 is a gear attached to the rotating shaft 3 of motor 1, and 4Fi gear 2
a rotating plate meshing with the gear 4; a cam 6 attached to one side of the rotating plate 5; 7 a head base to which the head 8 is attached and supported movably as appropriate; , 9 is a spring for pulling the head base 7, 10 is a sulkite pin attached to the head base 7 and engaged with the cam 6, l
l is the number of cassettes. In this head drive mechanism, when the motor 1 is driven, the rotating plate 5 is rotated via the gear 2.4. Head base 7Fi guide bin 10 to 9
Since it is engaged with the cam 6 through the rotation plate 50, the head plate 7 moves in the left-right direction in the figure along the shape of the cam 6, and the head 81a plays, PAUSE, FF/
Take the REW and STOP positions. Figure 2 shows the relationship between the rotation angle of the rotating plate 50 and the position of the head 8 based on the 5TOP position.Due to the rotation of the rotating plate 5, the head 8 moves from the 5TOP position to the FF/REW position and RAUSE.
It sequentially moves to the 5TOP position and the PLAY position, and returns to the 5TOP position. Incidentally, by reversing the motor 1, the head 8 can also be moved in the opposite direction.

The present invention provides a magnetic reproducing device in which the head is moved by a motor as described above, and by effectively braking the motor when moving the head, the time for positioning the head is shortened and operability is improved. The object of the present invention is to provide a head position control method that can perform the following functions.

Embodiments of the present invention will be described below with reference to the drawings.

In 11B311, 12 is a control circuit consisting of a microcomputer, 13 is a switch circuit for each operation switch, 14 is an apricot drive and display circuit to which the output of the control circuit 12 is applied, 15 is a Schmitt circuit, and 16 is a rotating plate 5. A reflecting plate 17 attached to the other surface of the PL, a photoreflector 18 consisting of a light emitting element and a light receiving element, and a PL
PLAY position switch 1 that is mechanically turned on in the AY position
Herad position detection circuit with 9, 20Fi output line 21.
22 is a control circuit 12Km & a forward/reverse drive circuit for the motor 1, 23 is a 11.3V power supply terminal of the forward/reverse drive circuit 20, a 24-wire constant voltage circuit, and a constant voltage circuit 24 is a 7V
The base of the transistor 26 is connected to the control circuit 12 via an output line 27.

Further, 28 is a discrimination circuit.

Next, the operation of the above device is as follows: PL the head 8 from about 5TOP.
The case of moving to the AY position will be explained with reference to FIG. 4. FIG. 4 is a time chart of input and output in the control circuit 12. At this point, when the PLAY switch is turned on, a signal is sent from the switch circuit 13 to the control circuit 12. As a result, the outputs of the outputs 121 and 22 become "L" and "H" at time point (3) of the control circuit 12Fi, the motor 1 rotates in the normal direction via the drive circuit 2o, the rotating plate 5 also rotates, and the head 8 moves. Start. Output line “L” of output-27
Since the transistor 26 is off, the motor 1 is 11.
Rotates at high speed with a high voltage of 3V. At this time, the reflector 17 also
At the time (3) when the light receiving element of the photoreflector 18 has passed through the 5TOP position, the light receiving element of the photoreflector 18 receives light from the reflection plate 17, and the output of the photoreflector 18 becomes rHJ. Since the reflector 17 has unevenness, the output of the 7-o-reflector 18 is then r
When it passes the FF/REV position, it turns to rHJ again, and when it reaches the PAUSE position, it turns to rL.
It becomes J. The output of the photoreflector 18 is applied to the control circuit 12 via the Schmitt circuit 15 and counted.

As a result, the control circuit 12 detects that the PAUSE position has been reached, and sets the output of the output line 27 to "H". Therefore, the transistors 2 and 6 are turned on, the output of the constant voltage circuit 24 becomes 7V, and the motor 1 rotates while reducing its inertia due to low voltage drive.

At the time (2) when passing the PAUSE position, the output of the photoreflector 18 becomes fi i (J, and at the time (2) when the PLAY position is reached, the output becomes U[LJ. At this time, the output line 21.
The output of 22 is switched to fHJ and rLJ, and the motor 1 is energized in the reverse direction through the main body circuit 20, and the output of the output line 27 also becomes rLJ, so the motor 1 is driven at a high voltage. At time point (3), the outputs of the line force lines 21 and 22 both become rHJ, so the motor l is de-energized via the drive circuit 20. still,
The PLAY position switch 19 is turned on between times ■ and ■.

In this manner, in the above device, the motor 1 is driven at low pressure to reduce its inertia during the period from when the head 8 reaches the PAUSE position to when it reaches the PLAY position, that is, during period D in FIG. Since the motor 1 is energized in the reverse direction and then stopped for a certain period of time after reaching , the motor 1 is braked in the reverse direction, and braking -11A shown in FIG. 5 is close to critical braking. In addition, B is the motor l as before.
C shows a case in which the brake is driven at low pressure from beginning to end, and C shows a case in which braking is performed while driving at a high pressure. In both cases, the braking time becomes longer.

Moreover, FIG. 6 shows the relationship between the applied voltage of the motor 1 and the reverse current energization time, in which A is the conventional case (without pressure cutting group), B is the case at high voltage in this embodiment, and B is the case in this embodiment at high voltage. Indicates low voltage. In this embodiment, since the voltage is set to a low voltage before the target position, as shown in the figure, the reverse direction energization time width during which the stroke position can be stopped can be increased, and the reliability of the target position stop is improved.

Although the voltage of the motor 1 during reverse direction energization is set to a high voltage in the above embodiment, it may be a low voltage.

As described above, in the present invention, since the motor is driven at high voltage and high speed until it reaches a position just before the target position of the head, the head can be positioned at high speed, and after that, the motor is driven at low voltage. Since the motor is reversely braked when the target position is reached, the motor can be braked in a short time, reducing the head positioning time and improving operability. I can do it. Further, since the motor is operated at a low voltage before the monthly salary position, the time period for which the motor is energized in the reverse direction can be increased, and the reliability of accurately stopping the head at the target position is improved.

[Brief explanation of drawings]

Figure J1!1 is a perspective view of the head drive mechanism of the magnetic reproducing apparatus according to the conventional art and the present invention, No. 21 is a diagram of the relationship between the rotation angle of the rotating plate and the head position in the magnetic reproducing apparatus according to the conventional art and the present invention, and No. 3 Fig. 4 is a time chart of the head position control device of the magnetic reproducing apparatus according to the present invention, Fig. 5 is a braking curve diagram, and Fig. 6 is a diagram of the motor. FIG. 4 is a diagram showing the relationship between applied voltage and reverse energization time. 1... Motor, 5... Rotating plate, 6... Cam, 7...
... Head base, 8... Head, 12... Control circuit, 13... Switch circuit, 16... Head position detection circuit, 17... Reflector, 18... Photo reflector, 20...・Forward/reverse drive circuit, 21, 22, 27...
- Output line, 23...Power terminal, 25...Zener diode, 26...Transistor. In addition, the same symbol indicates the same or equivalent part. Agent Nobu Tsutano −

Claims (3)

[Claims] (1) The head position is moved by motor drive.In the magnetic reproducing device, the motor is driven at high voltage until it reaches the position 11 before the target position of the head, and after that, the drive motor is driven at low voltage. , a head position control method for a magnetic reproducing device characterized by temporarily energizing the IIKa motor in the opposite direction when the head reaches the target position, and then stopping energizing the motor. (2) A head position control system for a magnetic reproducing apparatus according to claim 1, wherein the temporary reverse current supply to the motor is performed using a high voltage. (3) A bond position control method for a magnetic reproducing device according to claim 1, wherein the temporary reverse current supply to the motor is performed using a low voltage.