JPS58147862A - 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 feeding a motor in the opposite direction temporarily when the head moves to a desired position, and then stopping feeding the motor and braking the motor excellently. CONSTITUTION:When a play switch PLAY is turned on, a signal is sent from a switch circuit 13 to a control circuit 12. Consequently, outputs of output lines 21 and 22 are held at L and H respectively and the motor 1 rotates normally through a driving circuit 20 to rotate a rotary disk, thereby allowing the head to start moving. In this case, a reflecting plate 17 is rotated and the photodetecting element of a photoreflector 18 receives light from the reflecting plate 17 right behind a stop position STOP to generate an output H and generates an output L on arrival at a play position PLAY. The control circuit 12 once detecting the arrival at the position PLAY changes the outputs of the output lines 21 and 22 to H and L respectively and through the driving circuit 20, the motor 1 is fed with a reverse current. Then, the output of the output line 22 also goes up to H and the feeding to the motor 1 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on a head position control method for a magnetic reproducing apparatus such as a tape recorder.

For erasing in magnetic playback devices such as tail recorders,
Recording and playback heads are driven by motors. In FIG. 1, there is a motor L, a gear attached to the single rotation shaft 3 of the motor L, 4 a gear that meshes with the gear 2, 5 a rotating plate that meshes with the L gear 4, and 6 one side of the rotor 5. A cam 7Fi is attached to the surface of the head 8, and a head base 9 is movably supported, and 9 is a spring for opening the helad base 7. The guide pin 11 that engages with is the cassette tube. Here, when the motor 1 is powered, the rotating plate 5 rotates via the gear 2.4. Since the head base 7/fi is engaged with the cam 6 via the guide pin lO, the head base 7 moves along the shape of the cam 6 by the rotation of the rotating plate 50, and the head 8 moves to the PLAY position.
, PAU SE , FF/REW and 5TOP positions. Figure 2 shows the rotation angle of the rotating plate 50 and the spatula 18.
The relationship with the 0 position is shown based on the 5TOP position.
P position 11 color FF/R1 (moves sequentially to W position, PAUSE position and PLAY position, returns to 5TOP position.

The motor 1 can be rotated in forward and reverse directions, and 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, by effectively braking the motor when moving the head, thereby shortening the time for positioning the head and improving operability. The purpose of this invention is to provide a head position control method that can

Hereinafter, nine examples of the present invention will be explained with reference to the drawings.

In FIG. 3, 12 is a control path consisting of a microcomputer, 13 is a switch circuit having each operation switch, 14 is an anzo section movement and display circuit to which the output of the control circuit 12 is applied, 15 is a Schmitt circuit, Reference numeral 16 denotes a reflecting plate 17 attached to the external force surface of the rotary plate 5, a photoreflector 18 consisting of a light emitting element and a light receiving element, and a PLA.
PLAY position switch 19 mechanically turned on in Y position
The head height is 1 m [detection path, 20 is the output line 21.
A forward/reverse drive circuit for the motor 1 connected to the control circuit 12 via 22, 23 a power supply terminal, 24 a constant voltage circuit, 25
#-L, discrimination circuit;

explain. Figure 4 shows head 8 in PLA with about 5 TOP.
A time chart is shown when moving to Y position k. When the PLAY switch is turned on at time point (3), a signal is sent from the switch circuit 13 to the control circuit 12. As a result, the multi-control circuit 12 outputs the output lines 21 and 22 (LJ, rH) at time point (3), and outputs the motor l via the drive circuit 20.
rotates in the normal direction, the rotary plate 5 also rotates, and the head 8II'i begins to move. At this time, the reflection plate 17 also rotates, and since the light receiving element of the Fi7 o-reflector 18 receives the light from the reflection plate 17, the output becomes "H" after passing the 5TOP position.

The output of the photoreflector 18 then becomes "L" and F.
When it passes the F/REW position, it becomes HJ again)
, after that, when it becomes "L" and passes the PAUSE position, rl (J, when it reaches the PLAY position, tir
Becomes LJ. This output is applied to control 1 path 12 via Schmitt circuit 15 and counted. This control 1
The circuit 12 detects that the PLAY position has been reached, switches the outputs of the output lines 21 and 22 to rHJ and rLJ, and causes a reverse current to flow through the motor l via the drive circuit 20. At this point, the output of the output -22 also becomes rHJ, and the motor l is stopped energized via the drive circuit 20. Time point■,■
For example, the time between PLAY
The position switch 19 is turned on between times ■ and ■.

In this way, in the above device, when the head 8 moves to the desired position, a reverse current is temporarily applied to the motor 1, so the motor 1 attempts to reverse the direction, and the inertia of the & movement mechanism of the head 8 is removed. 1 is braked. Therefore, the motor 1 is subjected to critical braking (braking coefficient ζ=1
), the control is stopped, the head 8 is also stopped,
The time required to position the head 8 is shortened. Direction, B in Figure 5
When fliI&l is ζ>1, the C curve shows the case when ζ is low, and the braking time becomes longer in either case.

Incidentally, it is preferable that the idle direction energization time of the motor 1 can be varied depending on the time for positioning the spatula 180 or in accordance with the pressure angle characteristics of the cam 6.

As described above, in the magnetic reproducing apparatus of the present invention, when the head is moved by the motor, the VC temporarily energizes the motor in the opposite direction when the head moves to a desired position,
After that, the motor is de-energized. Because of this, the motor poetically tries to rotate backwards, driving the head 4! l
! The inertia of the structure is effectively eliminated. Therefore, the braking of the motor and head is close to critical braking, the time for positioning the head can be shortened, and the operability is improved.

[Brief explanation of drawings]

1 is a perspective view of a head drive mechanism of a magnetic reproducing device according to the conventional art and the present invention; FIG. FIG. 4 is a block diagram of a head position control device of a magnetic reproducing device according to the present invention, a time chart of head position control of the magnetic reproducing device according to the present invention, and a braking curve diagram of tJIJ5. 1... Motor, 2, 4... Gear, 5... Rotating plate,
6...Cam, 7...Head base, 8...Head, 12...Control circuit, 13...Switch circuit, 16
...Head position, detection oil path, 17...Reflector, 1
8... Photoreflector, 20... Motor forward/reverse drive circuit, 21.22... Output line. Note that the same reference numerals indicate the same or equivalent parts. Agent Shin Kuzuno −

Claims (2)

[Claims] (1) In a magnetic reproducing device in which the head position is moved by motor drive, when the head moves to a desired position, the motor is temporarily overcharged in the opposite direction, and then the motor is no longer energized. A head position control method for a magnetic reproducing device characterized in that the head position is stopped. (2) The reverse direction energization time of the motor is ``head position i''.
The head position l of the magnetic reproducing apparatus according to claim 1, characterized in that the head position l is determined according to the t output time.
111tllllI method.