JPH0140411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to protection of the tape and rotary head of a rotary head type magnetic recording and reproducing device, such as a video tape recorder (hereinafter abbreviated as VTR).

Conventional structure and its problems When recording and reproducing information on a magnetic tape using a rotating head, especially when the magnetic tape is stored in a cassette, the magnetic tape is pulled out from the cassette, wound around a rotating cylinder, and then attached to the head on the tape. A method is used to bring them into contact with each other. That is, in FIG. 1, a tape 3 is pulled out from a cassette 1 by a loading mechanism (not shown) and wound around a rotating cylinder 2. Normally, the rotary cylinder 2 is rotating, and an air film is formed between the cylinder 2 and the tape 3, so that the tape 3 runs smoothly. However, since the tape 3 and the rotating head 6 are in contact with each other, the following problem occurs. That is, when the tape is not running, the rotary head 6 always draws the same trajectory on the tape 3, and if this state continues for a long time, the recording medium on the tape will peel off. There was a risk of damaging the tape.

Conventionally, this problem has been dealt with as follows. The first possibility is to stop the rotating cylinder 2 when the vehicle is stopped for a long time. This solves the problem of peeling of the recording medium. However, this method causes the following problem.
In other words, an air film will no longer be formed between the tape 3 and the rotating cylinder 2, and if left unused for a long time, the tape will adhere to the cylinder, making it impossible to restart the rotating cylinder 2, or causing damage to the rotating cylinder 2. It can wrap around itself two or three times.

Also, if we consider the case of recording scenery or a story with a TV camera and VTR, it is necessary to change the scene or set the scene.
Since the tape is often left in a stopped state for a relatively long period of time, conventional methods cannot cope with this problem.

Next, as a second method, there is a method of unloading the tape 3 into the cassette 1, but in this case,
There is the following problem. That is, when loading and unloading tape 3, tape 3
However, it is necessary to perform feeding or winding using either reel 4 or reel 5. For example, the reel 5 feeds the tape during loading and winds the tape during unloading, and the reel 4 is completely fixed during loading and unloading. If you do this,
Even if loading and unloading are repeated, the tape can always be in the same position during loading, but by keeping one reel completely fixed, loading and unloading can be done without damaging the tape 3. The problem is that it is difficult. Furthermore, loading and unloading operations take time, and as a VCR, it lacks maneuverability.

Purpose of the Invention The present invention overcomes these drawbacks of the conventional art, and provides a magnetic recording and reproducing device that does not damage the tape even if the tape position remains unchanged when the tape is stopped running for a long time. The purpose is to

Structure of the Invention In order to achieve the above object, the present invention provides means for winding a cylinder including a rotary head, a recording/reproducing circuit, a control circuit for rotating the rotary head at a constant speed, and an output of the speed control circuit. It has a cylinder motor drive circuit that amplifies and drives the cylinder motor on/off control, and a sequential control circuit that controls the mode of the device. By issuing motor on/off commands from the sequential control circuit to the motor drive circuit, the rotation of the rotating head is intermittently controlled on and off, thereby extending the life of the tape and preventing tape from sticking to the rotating head cylinder. This has the effect of making it possible to reduce the power consumption of the device.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings. FIG. 2 is a circuit block diagram. When the microcomputer 11 issues an ON command to the motor drive circuit 12, the rotary cylinder motor 13 starts.
The rotary cylinder motor rotates at a constant speed and with a constant phase through a loop composed of the rotation detector 14, the control circuit 15, the motor drive circuit 12, and the rotary cylinder motor 13. and microcomputer 1
1 issues an off command to the motor drive circuit 12,
Since the motor drive circuit 12 ceases to operate, the rotary cylinder motor 13 stops.

Next, the operation of the microcomputer 11 will be explained based on FIG. 3, which is a flowchart showing the processing of the microcomputer. When the VTR enters the stop mode, it starts an m-minute timer, stops the cylinder motor for m minutes, and waits for the next input. Inputs include tape running (recording, playback, fast forwarding, rewinding, etc.) or tape ejection. If there is any input, it will return to normal driving mode. If there is no input for m minutes, a l second timer is started, an ON command is issued to the cylinder motor, and an input is waited for. If there is no input for l seconds, add 1 to the loop counter. If the loop counter is smaller than the constant value a, m again
Start the minute timer, stop the cylinder motor, wait for input, and repeat the same operation. That is, the command to the cylinder motor has a waveform as shown in FIG. When the loop counter reaches the value a, it is determined that the device has forgotten to turn off the power, the tape is unloaded, and after the unloading is completed, the device is turned off.

For example, if the peeling life of the recording medium on the tape by the rotating head is 10 minutes and the time the tape starts to adhere to the rotating cylinder is 20 minutes, then the constants for each variable are set as follows.

m = 10 minutes, l = 3 seconds, a = 50 If you set it like this, the cylinder motor will last approximately 10 minutes.
Since it is turned on for 3 seconds every minute, it is possible to prevent the tape from sticking to the cylinder. In other words, the time a(m+l) that can be left with the tape stopped is 502 minutes 30
Although there are seconds, the rotation time of the cylinder motor is 2 minutes and 20 seconds, which is not the time at which the recording medium on the tape starts to peel off. Moreover, the short rotation time of the motor has the effect of extending the life of the motor and reducing power consumption, especially in the case of a brushed motor.

Furthermore, even if you forget to turn off the power while the tape is stopped, the power can be turned off automatically, which can be said to have a sufficient effect on the safety of the apparatus.

We also assume that a TV camera and VTR are used to photograph landscapes and stories outdoors. Particularly when using a battery as a power source, the camera is turned off in a power-down mode to reduce battery consumption while setting a scene or landscape, etc. At this time, the power consumption of the VTR is reduced. It is clear that this is desirable. However, as described in the conventional example, if the power down mode continues for a long time with the tape wrapped around the cylinder, problems will occur between the tape and the rotating cylinder. However, even in this power down mode, the problem between the tape and the rotating cylinder can be solved by using the present invention. Furthermore, in the present invention, since the cylinder motor is almost stopped, the current of the motor is negligible, making it practical as a power down mode.

The second embodiment will be explained with reference to the flowchart shown in FIG. 5 which shows the processing of the microcomputer. When the VTR is in stop mode, it starts the n minute timer and
Leave the cylinder motor rotating for a minute and wait for the next input. If there is an input, the VTR shifts to normal running mode or tape ejection. If there is no input for n minutes, the loop counter is set to zero, the cylinder motor is turned off for m minutes, and the cylinder motor is turned on for l seconds, the same mode as in the previous embodiment. The subsequent operations are exactly the same as those in the previous embodiment, so the explanation will be omitted. In this embodiment, the cylinder motor continues to rotate for n minutes after entering the stop mode, so if a recording or playback input is received within n minutes, it is extremely easy to transition to the recording or playback state. It has the advantage of being

For example, assuming the same tape and cylinder conditions as in the previous example, and assuming n = 5 minutes and other constants remaining at exactly the same values, the time n+a (m+l) that can be left in the tape stopped state is 507 minutes30 The rotation time of the cylinder motor is 7 minutes and 30 seconds, indicating that no problem will occur.

FIG. 6 shows a third embodiment, which is an improvement on the second embodiment. If an input occurs during the m-minute timer, that is, while the cylinder motor is stopped,
A P second timer is started, during which the rotation of the cylinder motor is increased, and after the P second timer has elapsed, the mode is moved to the next mode. By doing this, even when moving from a state where the rotation is stopped to the next mode, the tape will run only after the rotation has increased sufficiently.

In this embodiment, a case has been described in which the upper cylinder part of the head cylinder and the head tip rotate as one unit, but a method in which the upper cylinder part and the head are separate, that is, the upper cylinder part is fixed, is also possible. It is clear that the present invention has similar effects even when only the head rotates.

Effects of the Invention As is clear from what has been described above, although the present invention has a simple configuration, it does not cause the recording medium of the tape to peel off, and the tape and the rotating cylinder section do not adhere to each other. In addition, the tape position does not shift, ensuring continuity of recording, and since the cylinder motor is almost stopped, power consumption can be reduced, and the life of the motor is not compromised. It has the following.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the mechanical structure of the tape and rotating head cylinder in the present invention, Fig. 2 is a block diagram showing the configuration of an embodiment of the invention, and Fig. 3 uses the embodiment of Fig. 2. Flowchart showing the processing procedure of the microcomputer, FIG. 4 is a waveform diagram of the motor command, FIG. 5 is a flowchart showing the processing procedure in the second embodiment, and FIG. 6 is the processing procedure in the third embodiment. FIG. 1...cassette, 2...rotating cylinder, 3...
Magnetic tape, 6... Rotating head, 11... Microcomputer, 12... Motor drive circuit, 13
...Cylinder motor, 15...Control circuit.

Claims (1)

[Scope of Claims] 1. A means for winding a tape from a cassette onto a cylinder including a rotating head, a circuit for recording and reproducing information on the magnetic tape by the rotating head, and a speed control circuit for rotating the rotating head at a constant speed. and,
It has a cylinder motor drive circuit that amplifies the output of the speed control circuit to control and drive the cylinder motor on and off, and a sequential control circuit that controls the mode of the apparatus. A magnetic recording/reproducing device characterized by instructing a cylinder motor to be intermittently turned on and off while a tape is wound around the cylinder. 2 The sequential control circuit intermittently controls the cylinder motor on and off when the tape stops running.After a certain period of time has elapsed, the tape is unwound from the cylinder and stored in the cassette, and then the device's power is turned on. 2. The magnetic recording and reproducing device according to claim 1, wherein the magnetic recording and reproducing device is configured to cut . 3 The sequential control circuit has a first mode in which the cylinder motor is continuously rotated when the tape is stopped, and a second mode in which the cylinder motor is intermittently controlled on and off. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording/reproducing apparatus is in the first mode and shifts to the second mode after a certain period of time has elapsed. 4. In the second mode in which the cylinder motor is rotated intermittently, when a tape running instruction is received, the sequential control circuit shifts to the first continuous rotation mode and then starts tape running after a certain period of time has elapsed. A magnetic recording and reproducing apparatus according to claim 3 characterized in that the magnetic recording and reproducing apparatus is characterized in that: