JPS61196455A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To allow a tape to travel smoothly at a high speed without causing any damage by applying a driving circuit with a control voltage which varies continuously and slowly at the time of switching from a stop mode to a high- speed mode and increasing the rotating speed of a driving motor. CONSTITUTION:When the stop mode is changed over to the FF mode, a switch 25 is closed to the side of a contact (m) and a switch 21 is closed to the side of a contact (d), so the output (a) of a speed control circuit 11 is supplied to the driving circuit 12 through a resistance 29, the switch 25, and the switch 21. The voltage applied in this case is the voltage charged in a capacitor 26 right after the stop mode is changed to the FF mode, i.e. the voltage of the output (h) of a tension control circuit 19 and then rises with time according to the curve (charging characteristics) determined by the relation between the resistance 29 and capacitor 29. When the speed of the tape approximates the normal speed in the FF mode, a switch 27 is turned off with the output signal thetaof a speed detecting circuit 28.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to magnetic recording and reproducing devices such as video tape recorders.

2. Prior Art FIG. 2 is a schematic diagram of a control circuit for a reel drive motor of a conventional magnetic recording device. 1 is a magnetic tape, 2 is a supply reel, 3 is a take-up reel, 8 is a reel motor that drives the supply reel 2, and 7 is a reel motor that drives the take-up reel 3. The tension sensor 15 electrically detects the amount of movement of the tension lever 14 in proportion to the magnitude of the tension of the magnetic tape (hereinafter simply referred to as tape) at the outlet of the supply reel 2 using a photointerrupter and a light barrier plate attached to the tension lever 14. It is used to convert signals into signals. This electric signal is applied to the tension control circuit 16, and the control signal @C is applied to the drive circuit 13 via a switch 20 (the switch 20 closes to the contact side except in the REW mode where the tape is run at high speed in the reverse direction). The reel motor 8 is controlled to keep the tape tension constant at the outlet of the supply reel 2.The tension sensor 18 controls the amount of movement of the tension lever 17 in proportion to the tape tension at the inlet of the take-up reel. It is converted into an electric signal j by a photointerrupter and a light shield plate attached to the tension lever.This electric signal j is applied to the tension control circuit 19, and its Ill
The ill signal is supplied to the drive circuit 12 via the switch 21 (the switch 21 is closed to the e side except in the FF mode in which the tape is run at high speed in the forward direction), and the take-up reel 3
The reel motor 7 is controlled to keep the tape tension at the entrance constant.

When switching from stop mode to FF mode, switch 21
is closed to the contact d side, and the output a of the speed control circuit 11 is supplied to the drive circuit 12 via the switch 21.

Reference numeral 4 denotes a tape speed detection roller having an extremely small inertial force that rotates in response to the running force of the tape 1; 5 is attached to the rotating shaft of the tape speed detection roller 4; notches or shading are provided at equal intervals on its circumference; The O-tary encoder 6 is a photointerrupter for obtaining pulse signals from the rotating rotary encoder 5. Tape 1 in FF mode
The tape is wound from the supply reel 2 through a head device (not shown), a cylinder 9, a tape speed detection roller 4, and a take-up reel 3. At this time, the running speed of the tape 1 is a pulse signal obtained from a photointerrupter 6 consisting of a light emitting element and a light receiving element by the rotation of a rotary encoder 5 attached to a tape speed detection roller 4 whose rotational speed changes in proportion to the speed. detected as the frequency of

The pulse signal passes through the waveform shaping circuit 10 and is applied to the speed control circuit 11 as the speed control signal l. The output a of the speed control circuit 11 is sent to the drive circuit 12 via the switch 21.
The reel motor 7 is controlled so that the tape speed is constant. The output a of the speed control circuit 11 increases when the tape speed is slower than the normal speed in the FF mode, and decreases when the tape speed is faster, thereby controlling the reel motor 7 so that the tape speed is constant.

Problems to be Solved by the Invention In such a conventional configuration, immediately after the stop mode is switched to the FF mode, the tape is not running yet, so the output a of the speed control circuit 11 is at its maximum.

Since this output is supplied to the drive circuit 12 via the switch 21, the torque of the reel motor 7 becomes abnormally large, causing abnormal tension to be applied to the tape as the tape is rapidly wound by the take-up reel 3, causing damage to the tape. It had an rIam point that it was the cause of. When switching from stop mode to REW mode, the operation is the opposite of the above.
There are similar problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording/reproducing device that allows a stopped tape to run smoothly at high speed without being subjected to impact.

Means for Solving the Problems The magnetic recording and reproducing apparatus of the present invention includes at least one reel motor that rotates a tape reel, a drive circuit that drives the reel motor, and a drive circuit that controls the tension of the tape in a stop mode that stops the tape. a power storage circuit that holds a tension control signal in the drive circuit so as to keep the tension constant; and a speed control circuit that supplies a speed control signal to the drive circuit so as to keep the tape speed constant in a high speed mode in which the tape runs at high speed. , an integrating circuit including the storage circuit inserted between the speed l1IJ- circuit and the drive circuit so as to continuously and slowly change the voltage supplied to the drive circuit when switching from stop mode to high speed mode; and tape speed. The present invention is characterized in that a separation timing determination circuit is provided which detects the speed and separates the integrating circuit when the speed exceeds a certain certain value.

Effect: With this configuration, when switching from stop mode to high-speed mode, a continuously and slowly changing control voltage is applied to the drive circuit to gradually increase the rotation speed of the drive motor, so the switch can be made smoothly without damaging the tape. It is capable of running at high speed.

EXAMPLE An example of the present invention will be described below with reference to FIG. Components having the same functions as those in FIG. 2 are given the same reference numerals and their explanations will be omitted.

In the stop mode, the reel motor 7 serves to keep the tape tension at the entrance of the take-up reel constant. At this time, the output of the tension control circuit 19 is transferred to the buffer amplifier 23.
is converted to low impedance by switch 25 (
In other than the FF mode, the switch 25 is connected to the + side terminal of the capacitor 26 via a contact (closed to the n side). One terminal of the capacitor 26 is connected to ground via a switch 27 (which is ON in the stop mode). The buffer amplifier 23 converts the impedance so that the output of the tension control circuit 19 is not affected by the capacitor 26, and the voltage values of the input and output of the buffer amplifier 23 do not change. Therefore, the capacitor 26 is charged to the voltage at the output of the tensicon control circuit 19.

Similarly, the capacitor 30 is connected to the buffer amplifier 22 and the switch 24.
(The switch 24 is closed to the contact side in modes other than the REW mode) and is charged to the voltage of the output C of the tension control circuit 1G.

When switching from the stop mode to the FF mode, the switch 25 closes to the contact ■ side and the switch 21 closes to the contact d side, so the output a of the speed ma circuit 11 is connected to the resistor 29 and the switch 25.
, are supplied to the drive circuit 12 via the switch 21. However, at that time, the supplied voltage is the voltage charged in the capacitor 26, that is, the voltage at the output of the tension control circuit 19 immediately after switching from the stop mode to the FF mode, and then as time passes, the voltage supplied to the resistor 26 , the curve (charging characteristics) determined by the relationship of the capacitor 26 is drawn and becomes larger. When the running speed of the tape approaches the normal speed in the FF mode, the switch 27 is turned off by the output signal θ of the speed detection circuit 28.

When switching from stop mode to REW mode, press switch 2.
4 is tilted to the contact A side, and switch 2G is tilted to the contact G side, so the drive circuit 13 has a tension of 141 immediately after switching.
The voltage of the output C of the 9@ path 16 is supplied, and then increases as time passes, drawing a curve (charging characteristic) determined by the resistor 29 and capacitor 30. The timing for turning off the switch 21 is the same as when switching from stop mode to FF mode.

As described above, according to this embodiment, when switching from the stop mode to the FF mode, the drive circuit 1 receives a voltage that gradually becomes larger than the output voltage of the tension control circuit 19.
2, the tape will not be suddenly wound onto the take-up reel 3 and cause damage to the tape. The same thing can be said when switching from stop mode to REW mode.

As described in the detailed description of the invention, the magnetic recording and reproducing apparatus of the present invention includes at least one single motor that rotates a tape reel, a drive circuit that drives the reel motor, and a drive circuit that controls the tension of the tape in a stop mode that stops the tape. a tensicon control circuit that supplies a tension control signal to the drive circuit so as to keep it constant; a power storage circuit that holds the tension control signal; A speed control circuit that supplies a speed control signal to the circuit and a voltage that is supplied to the drive circuit when switching from stop mode to high speed mode is inserted between the speed control circuit and the drive circuit so that the voltage that is supplied to the drive circuit is continuously and gradually changed. It is composed of an integrating circuit including the electricity storage circuit and a separation timing judgment circuit that detects the tape speed and separates the integrating circuit when the speed exceeds a certain level, so that a stopped tape can be smoothly run at high speed without damage. The excellent effect of being able to transition to . This effect provides the effect of preventing damage to the tape due to tape damage.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a control circuit for a reel motor of a magnetic recording/reproducing apparatus according to the present invention, and FIG. 2 is a block diagram of a control circuit for a reel motor of a conventional magnetic recording/reproducing apparatus. DESCRIPTION OF SYMBOLS 1... Magnetic tape, 2... Supply reel, 3... Take-up reel, 4... Tape speed detection roller, 5-way rotary encoder, 6... Photo interrupter, 7...
・Reel motor, 8... Reel motor, 9... Cylinder, 10... Waveform shaping circuit, 11... Speed 1t
ljl11 circuit, 12... drive circuit, 13... motor drive circuit, 14... tension lever, 15...
Tension sensor, 16...Tension control circuit, 1
7... Tension lever, 18... Tension sensor, 19... Tension control circuit, 2o... Switch, 21... Switch, 22... Buffer amplifier, 23
...svi amplifier, 24...switch, 25...
Switch, 26... Capacitor, 27... Switch, 28... Speed detection circuit, 29... Resistor, 3°...
・Capacitor

Claims (1)

[Claims] 1. At least one reel motor that rotates a tape reel, a drive circuit that drives the reel motor, and a tension control signal that supplies a tension control signal to the drive circuit so as to keep the tension of the tape constant in a stop mode that stops the tape. a tension control circuit, a power storage circuit that holds the tension control signal, a speed control circuit that supplies a speed control signal to the drive circuit so as to keep the tape speed constant in a high speed mode in which the tape runs at high speed, and a stop mode. the speed control circuit, an integrator circuit including the power storage circuit inserted between the drive circuit, and a tape speed detecting circuit so as to continuously and slowly change the voltage supplied to the drive circuit when switching from to high-speed mode; A magnetic recording/reproducing device comprising a separation timing determination circuit that separates the integrating circuit when the speed exceeds a certain certain value.