JPS6043571B2 - magnetic tape device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape device such as a video tape recorder.

Conventionally, in magnetic tape devices that record and reproduce video signals by forming diagonal tracks on a magnetic tape, a method has been known in which the magnetic tape is run intermittently to obtain slow-motion images with less noise during reproduction. There is.

At this time, it is necessary to rotate the capstan that runs the magnetic tape in steps, and if slow motion playback continues for a long time, the drive motor that drives the capstan will rotate and stop repeatedly, and a large current will flow when the drive motor starts. Due to this, the temperature of the motor windings increases, and this temperature increase increases the electrical resistance of the windings and reduces the magnetic force of the motor's rotor magnet, reducing the motor torque and preventing normal slow motion. There were times when images could not be obtained. For this reason, a timer has been developed that automatically switches to steady-speed playback when slow motion playback is performed continuously for a certain period of time, but this method does not allow long-term playback. If you perform slow motion regeneration again immediately after time skirmish regeneration and automatically switch to steady speed, slow motion regeneration is possible, and the temperature of the capstan drive motor increases and the motor torque decreases. Not only will normal slow motion reproduction not be possible, but there is also a risk that the insulation of the motor windings will deteriorate.Furthermore, if the drive motor and capstan are integrated, the heat generated by the drive motor will be transferred to the capstan. There were problems in that the magnetic tape in contact with the capstan would be deformed and the signals recorded on the magnetic tape would be demagnetized due to the temperature rise of the capstan. The present invention can solve the above-mentioned conventional problems by incorporating a temperature detection element in the drive motor to detect a temperature rise in the motor and prohibiting slow motion regeneration when the motor temperature is high. The present invention provides a magnetic tape device.

Hereinafter, the present invention will be explained based on illustrated embodiments.

The drawing is a configuration diagram of main parts of an embodiment of the present invention. In the drawing, by operating a playback operation button 1, a magnetic tape 2 is pulled out from a tape cassette (not shown) by a well-known tape loading mechanism, and is wound in an Ω shape around a rotating head cylinder 3. Rotating head cylinder 3
The video signal recorded on the magnetic tape 2 can be reproduced by at least one rotating magnetic head 4 built into the magnetic tape 2. Reference numeral 5 denotes a regeneration switch, which operates in conjunction with the regeneration operation button 1 and is connected to the capstan motor control circuit 6.

7 is a slow motion switch linked to the slow motion operation button 8.

Reference numeral 9 is an AND circuit to which the playback switch 5 and slow motion switch 7 are connected to the input side, and a signal is supplied to the timer circuit 10 when a slow motion operation is performed during playback.

The timer circuit 10 supplies a return signal to the capstan motor control circuit 6 to return to steady playback when the slow motion operation is performed for a certain period of time (for example, one minute) or more during playback. Furthermore, if the slow motion operation is canceled within a certain period of time (for example, one minute), a return signal for returning to steady playback is output, but the system is configured such that the playback signal does not return to normal playback.
11 is a capstan motor drive circuit, which is controlled by a control signal from the capstan motor control circuit 6;
The capstan motor 12, which is a drive motor, is driven.

Note that during slow motion reproduction, the capstan 5 motor drive circuit 11 supplies a pulsed voltage to the capstan motor 12, so that a slow motion image with less noise can be obtained. In the capstan motor 12 shown in a partially cutaway perspective view, a stator core 14 is fixed inside a motor housing 13, and a stator winding 15, for example, is attached to a large number of protrusions radially provided on the outer periphery of the stator core 14. It is wound in three-phase form.

Note that a temperature detection element 16 such as a thermistor 4 is bonded to a part of the stator winding 15 with an adhesive or the like in a manner that allows thermal connection. Further, a ring-shaped rotor magnet 17 whose inner circumferential surface is magnetized with multiple poles is arranged at a position facing the outer circumference of the stator core 14, and the rotor magnet 17 is placed inside a fly hole 18 provided rotatably. It has been incorporated. A capstan 19 is installed in the center of the fly hole 18.
is rotatably supported by a bearing 20 provided in the motor housing 13, and the pinch roller 21 is connected to the magnetic tape 2.
The magnetic tape 2 is configured to be able to travel by being pressed against the capstan 19 via the magnetic tape 2. The temperature detection element 16 is connected to a temperature detection circuit 22, and when the ambient temperature of the stator winding 15 rises above a predetermined temperature (for example, 100°C), a temperature rise signal is output to the capstan motor control circuit 6, and the capstan motor control circuit 6 outputs a temperature rise signal to the capstan motor control circuit 6. The control system of the stun motor control circuit 6 is configured such that when the temperature of the stator winding 15 exceeds a predetermined temperature (for example, 100° C.), slow motion regeneration is not performed even if the slow motion operation button 8 is operated. has been done.

Next, the operation and operation of this embodiment will be explained.

First, when the playback operation button 1 is operated, a tape loading mechanism (not shown) pulls out the magnetic tape 2 stored in the tape cassette in a loop shape to the outside of the tape cassette, around the rotating head cylinder 3. is wound around. At the same time, the rotary head cylinder 3 also starts rotating, and the pinch roller 21 comes into pressure contact with the capstan 19 via the magnetic tape 2. Simultaneously with the operation of the regeneration operation button 1, the regeneration switch 5 is also turned on, and the capstan motor control circuit 6 supplies a rotation control signal at a steady speed to the capstan motor drive motor drive circuit 11. The capstan motor 12 rotates at a steady speed, and the rotation of the capstan motor 12 causes the magnetic tape 2 to run at a steady speed. The signal is played back at a steady rate.

Next, when the slow motion operation button 8 is operated, the slow motion switch 7 is turned on, and a signal is supplied to the capstan motor control circuit 6 via the AND circuit 9 and the timer circuit 10, and the capstan motor drive circuit A pulsed voltage is supplied to the capstan motor 12 by the capstan motor 11 . As a result, the capstan motor 12
rotates intermittently to perform slow motion playback with little noise, and is configured such that the slow motion speed can be arbitrarily varied by means of a volume control 23. Also, if slow motion playback is performed continuously for more than a certain period of time (for example, 1 gin),
The timer circuit 10 automatically switches to normal speed regeneration to prevent the capstan motor 12 from overheating.

Immediately after switching to the steady speed, operate the slow motion operation button 8 again to perform slow motion playback, and if you repeat this, the capstan motor 12 will be rotating intermittently, so the startup at the time of motor startup will be delayed. Due to the current, the temperature of the stator winding 15 of the capstan motor 12 increases.

. The temperature of the stator winding 15 is detected by the temperature detection element 16 and the temperature detection circuit 22, and the temperature is set to a predetermined temperature (for example, 1
When it is detected that the temperature has risen above 00'C, the capstan motor control circuit 6 operates the slow motion operation button 8 until the temperature of the stator winding 15 falls below a predetermined temperature (for example, 80°C). Control is made so that slow-motion playback is not performed even if the In this case, this can be indicated by lighting the indicator lamp 24 connected to the capstan control circuit 6. As is clear from the above description, the present invention detects the temperature rise of the drive motor using a temperature detection element during intermittent running of a magnetic tape when the drive motor for rotating the capstan generates particularly intense heat, Since the magnetic tape is configured so that the magnetic tape cannot be run intermittently by the running control means in the event that It is also possible to prevent deterioration of motor performance due to deterioration of the insulation of the motor windings.

Furthermore, since the capstan is shared with the rotating shaft of the drive motor, it is easy to control the running of the magnetic tape, and even if the capstan and drive motor are integrated, the temperature of the drive motor does not rise above a specified temperature, so the capstan It is possible to prevent deformation of the magnetic tape and demagnetization of signals recorded on the magnetic tape caused by temperature rise, and it is possible to realize an excellent magnetic tape device with a simple configuration.

In the above-described embodiment of the present invention, the case of a cassette type video tape recorder was explained, but the case of an open reel type video tape recorder is essentially the same, and it goes without saying that it is included in the present invention. do not have.

[Brief explanation of the drawing]

The drawing shows the main part of an embodiment of the present invention. 6... Capstan motor control circuit, 12... Capstan motor, 16... Temperature detection element, 19...
Capstan, 22...Temperature detection circuit.

Claims (1)

[Scope of Claims] 1. A capstan for running a magnetic tape while holding it between a pinch roller, a drive motor for rotationally driving the capstan, and a drive motor for rotating the magnetic tape at a constant speed or intermittently. A running control means for controlling the magnetic tape to run at a constant speed or intermittently, and a temperature detection element for detecting a temperature due to heat generated by the drive motor, the temperature detecting element detecting the temperature during the intermittent running of the magnetic tape. A magnetic tape device, characterized in that a detection element detects a temperature rise of the drive motor, and when the temperature exceeds a predetermined temperature, the running control means prevents the magnetic tape from being intermittently run. 2. The magnetic tape device according to claim 1, wherein the temperature detection element is provided close to a winding of the drive motor. 3. The magnetic tape device according to claim 1 or 2, wherein the capstan is also used as a rotating shaft of the drive motor.