JPS6239494B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing device, and relates to a magnetic recording and reproducing device such as a video tape recorder (hereinafter referred to as VTR), in which a temporary stop is applied to temporarily stop tape running while playing back a magnetic tape. Regarding circuit improvement.

FIG. 1 is a schematic illustration of a VTR which is the background of this invention.

First, the overall configuration of the VTR will be explained.
A supply reel 2, a take-up reel 3, and a tape 4 are stored in the cassette storage section 1. The supply reel 2 is rotated by a motor 5, and the take-up reel 3 is rotated by a motor 6. The tape 4 can be moved upward by the movement of the guides 7 and 8. This is called loading. By loading, the tape wraps around the cylinder 9 by approximately 180 degrees. motor 10
is this loading and guide 7 and guide 8
This is a motor that provides power for the "unloading" operation that returns the robot to its original position. The motor 11 is a motor that rotates the cylinder 9. The capstan 12 is rotated by a motor 13, and the tape 4 is fed by pressing the pinch roller 14 against the capstan 12. The tape is fed by the capstan 12 mainly during recording and playback. In this case, the reel 3 and the capstan 12 are rotated clockwise by the motor 6 and the motor 13, respectively, with loading completed. Further, the reel 2 is pulled by the tape 4 and rotates clockwise. Also, when performing fast forwarding, make sure that the unloading is completed and the pinch roller 14 is
The pressure contact is released, and the reel 3 is rotated clockwise at high speed by the motor 6 to feed the tape 4. At this time, the reel 2 is pulled by the tape 4 and rotates clockwise. When rewinding, the unloading is completed and the pinch roller 14 is released from pressure, and the reel 2 is rotated counterclockwise at high speed by the motor 5 to feed the tape 4. At this time, the reel 3 is pulled by the tape 4 and rotates counterclockwise. In the above explanation, the pinch roller 14 is pressed against the plunger 1.
This is done by temporarily energizing 5. This pressure contact is maintained by continuously energizing the plunger 16.
The pressure contact is released by stopping the power supply to the plunger 16.

Next, control of the rotation speed will be explained. The control circuit 17 rotates the motor 11 when a signal 19 indicating the playback state or a signal 20 indicating the recording state is present from the mode control circuit 18.
7 is a constant rotation of the cylinder 9 (for example, per second
30 rotations). Furthermore, the vertical synchronization signal 2 is sent from the video circuit 22.
1, the rotation of the motor 11 is controlled so that the image heads 23 are aligned in the horizontal direction. When both the signal 19 and the signal 20 are not present, the rotation of the motor 11 is stopped.

Similarly to the control circuit 17, the control circuit 24 rotates the motor 14 when a signal 19 indicating the playback state or a signal 20 indicating the recording state is present from the mode control circuit 18, and when both the signal 19 and the signal 20 are received. When it does not exist, it acts to stop the rotation of the motor 14. The control circuit 24 controls the rotation of the motor 13 so that the speed of the tape 4 is constant (for example, 33.35 mm per second) during recording or playback. Furthermore, the rotation of the motor 13 is controlled so that the control pulse output 26 from the head 25 and the vertical synchronization signal 21 are synchronized.

Next, recording and reproducing of signals will be explained. During recording, the video signal applied to the video signal input terminal 27 is converted into an FM signal by the action of the video circuit 22, supplied to the video head 23, and recorded on the tape 4. At this time, the vertical synchronization signal 21 is supplied to the control circuit 17 and the control circuit 24. A video signal is then supplied from the video circuit 22 to the video signal output terminal 28. During playback, the output of the video head 23 is supplied to the video circuit 22, demodulated into a video signal and supplied to the video signal output terminal 28, and the vertical synchronization signal 21 is supplied to the control circuit 17.
and 24.

During recording, the audio signal applied to the audio signal input terminal 29 is supplied to the head 25 with a high frequency bias applied by the audio circuit 30.
recorded on tape 4. At this time, audio output terminal 3
1 is supplied with an audio signal, and a full-width erase head 32
A high frequency bias is applied from the audio circuit 30 to erase the previous recording. During reproduction, the output of the head 25 is supplied to the audio circuit 30, and an audio signal is supplied to the output terminal 31. The operations of the video circuit 22 and the audio circuit 30 are switched to recording or reproduction depending on the presence or absence of the signals 19 and 20.

Next, the mode control circuit 18 will be explained. The mode control circuit 18 has a mode switching output signal line 40.
45 and 70 are connected. Further, these output signal lines 40 to 42 and 70 are connected to a fast forward switch 33, a rewind switch 34,
A stop switch 35, a recording switch 36, a playback switch 37, and a pause switch 38 are connected. Switches 33 to 37 temporarily
When turned ON, the mode control circuit 18 cancels the previous mode and maintains the switch mode, and controls the control signals 19, 20, 46, etc. so that the operation of the motor and solenoid is adapted to that mode.
48, 50, 52 and 54 are issued. Also,
When the pause switch 38 is temporarily turned on during recording or playback, the mode control circuit 18 is operated to temporarily stop energizing the plunger 16 and release the pinch roller 14 from pressure. When the pause switch 38 is temporarily turned on again, the normal playback and recording state resumes. A rotation control signal 46 for the motor 5 is sent via a drive circuit 47 to rotate the motor 5 during rewinding and unloading to rotate the tape 4.
wind it up. Rotation control signal 48 for motor 6
The drive circuit 49 rotates the motor 6 to wind the tape 4 during fast forwarding, playback, and recording. A rotation control signal 50 for the motor 10 is transmitted through a drive circuit 51 to rotate the motor 10 during loading and unloading.

The control signal 52 for the plunger 15 is provided by a drive circuit 53.
The plunger 15 is driven through. A control signal 54 for the plunger 16 drives the plunger 16 via a drive circuit 53. The mode control circuit 18 that operates in this manner can be constructed using hardwired logic, but these days it can also be implemented using a microcomputer.

Next, a supplementary operation of the mode control circuit 18 will be explained. At the end of the tape 4, there is a non-magnetic part that allows light to pass through. When the tape 4 reaches the end during playback, recording, and fast forwarding, the light from the lamp 56 passes through and energizes the phototransistor 57. do. At this time, the drive circuit 57
is set to stop mode via the mode control circuit 18 in response to the control signal 58. Also, tape 4
At the beginning of the tape, there is a non-magnetic part that allows light to pass through, and when rewinding, the tape 4
At the beginning of , the phototransistor 59 becomes energized. At this time, the drive circuit 60 is operated and the control signal 61
As a result, the mode control circuit 18 causes the stop mode to be set. Furthermore, the rotating magnet 62 is coupled to the reel 3 by a belt 63, and as the reel 3 rotates, the rotating magnet 62 also rotates. The Hall element 64 detects a change in magnetic flux due to the rotation of the reel magnet 63, activates the drive circuit 65, and supplies a control signal 66 to the mode control circuit 18. Mode control circuit 18
When the control signal 66 is absent during recording, playback, fast forwarding, and rewinding, the system enters the stop mode. This is to prevent the risk of the tape 4 accumulating in the deck and damaging the tape 4 and the head 23 if the reel 2 continues to rotate even after the reel 3 stops rotating. Also, 67 is a humidity detector, and when the humidity exceeds 90%, the resistance value increases rapidly.
The drive circuit 68 supplies a control signal 69 to the mode control circuit 18 in response to this resistance value increase. At this time, the mode control circuit 18 operates to enter the stop mode. This prevents the tape 4 from wrapping around the cylinder and damaging the tape if there is dew condensation on the cylinder 9 in a high humidity condition.

Next, special playback will be explained. When the capstan 12 is stopped during playback, the video head 23 of the cylinder 9 passes through the same location on the tape, so
Still images can be obtained. This is achieved by turning on the pause switch during playback to stop the rotation of the capstan 12 while the pinch roller 14 is in pressure contact.

Furthermore, if the rotation speed of the capstan 12 is made faster than normal reproduction, an image that moves at a speed proportional to the rotation speed can be obtained. This will hereinafter be referred to as high-speed normal rotation playback. Furthermore, when the capstan 12 is rotated at high speed in the direction opposite to that of normal reproduction, it is possible to obtain an image that moves in the opposite direction at a speed proportional to the normal playback direction. This will hereinafter be referred to as high-speed reverse playback. This high-speed playback only works in playback mode.

A high-speed normal rotation regeneration switch 71 is provided to command the above-mentioned high-speed forward rotation regeneration, and a high-speed reverse rotation regeneration switch 72 is also provided to command high-speed reverse rotation regeneration. Furthermore, a special regeneration circuit 7 for controlling the motor 13 during special regeneration.
5 is provided. A control signal is given from the special reproduction control circuit 75 to the control circuit 24 during special reproduction. This special playback control circuit 75 includes:
A special reproduction instruction signal 77 is applied from the mode control circuit. Furthermore, a supply reel control signal for driving the first motor 5 that rotates the supply reel 2 is supplied from the special reproduction control circuit 75 to the drive circuit 47 .

FIG. 2 is a block diagram more specifically illustrating the capstan control system shown in FIG. 1, and FIG. 3 is an illustrative diagram showing temporal changes in the rotational speed of the capstan in a conventional VTR.

In the figure, a control circuit 24 for the motor 13 that drives the capstan 12 is composed of a rotation speed control circuit 24a that controls the rotation speed of the motor 13, and a transistor for inverting the output signal of the rotation speed control circuit 24a. Inverting amplifier 24b
, a resistor 24c connected to the collector of the transistor 24b, and a drive circuit 24d similarly connected to the collector of the inverting amplifier 24b.

The special regeneration control circuit 75 also includes a switching circuit 75a for switching between forward and reverse modes of the driving direction of the capstan.
and a capstan drive stop command circuit 75b which gives a drive stop command signal to the drive circuit 24d based on the stop command signal given from the mode control circuit 18.
, a switching circuit 75d that switches the stop command signal from the capstan drive stop command circuit 75b, and an OR gate 75j that receives the high-speed regeneration command signal output from the mode control circuit 18.
, a switching circuit 75e made of a transistor that switches the output signal of the OR gate 75j, and a resistor 75g connected between the collector of the transistor 75e and the collector of the inverting amplifier 24b.

In the conventional VTR configured as described above, when performing high-speed forward playback or high-speed reverse playback, the OR gate 75j,
A command signal is applied to the drive circuit 24d via the switching transistor 75e. On the other hand, the forward/reverse mode switching circuit 75a for the capstan driving direction is
The rotation direction of the motor 13 by the drive circuit 24d is determined according to the forward rotation command signal or the reverse rotation command signal. As a result, the capstan motor 13 rotates forward or reverse at high speed. If a temporary stop command is given in this state, mode control circuit 1
8, a command signal is given to the capstan drive stop command circuit 75b. The capstan drive stop command circuit 75b includes a switching transistor 75b.
is switched to turn off the control voltage applied to the drive circuit 24d. By that,
The voltage applied to the capstan motor 13 is turned off.

However, when the voltage applied to the capstan motor 13 is turned off by a temporary stop command in this way, the time it takes for the capstan 12 to stop becomes extremely long as shown in FIG. When the capstan 12 is stopped, the capstan 12 rotates in the opposite direction and reaches a stopped state, so that tape loosening is likely to occur between the supply reel 3 and the capstan 12. Therefore, there is a problem in that the video head 23 contacts the tape poorly and the image becomes distorted.

Therefore, the main object of the present invention is to ensure that the capstan is stopped from the forward rotation state even when performing reverse playback, and to stop the rotating force of the capstan at a predetermined speed or less to quickly and reliably stop the capstan. An object of the present invention is to provide a magnetic recording/reproducing device capable of temporarily stopping a magnetic tape.

In summary, the present invention includes means for rotating a capstan in the forward direction based on a temporary stop command, and means for stopping a motor that drives the capstan if the rotational speed of the capstan is equal to or less than a predetermined number,
This device is configured to play back images recorded on a recorded tape while the capstan is stopped.

The above objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

FIG. 4 is a schematic block diagram of one embodiment of the present invention. This FIG. 4 is the same as described above except that a rotation direction detector 73 is provided to detect the rotation direction of the motor 13 that drives the capstan 12, and a detection signal from this rotation direction detector 73 is provided to the motor control circuit 75. Same as Figure 1.

FIG. 5 is a concrete block diagram of a capstan control system according to an embodiment of the present invention. This FIG. 5 is the same as the above-mentioned FIG. 2 except for the following points. That is, a determination circuit 75h that determines the rotational direction of the motor 13 based on the detection signal of the rotational direction detector 73 shown in FIG. A rotation speed detection circuit 75i is newly included in the motor control circuit 75.

FIG. 6 is an illustrative diagram showing temporal changes in the rotational speed of the capstan for explaining the operations shown in FIGS. 4 and 5. FIG.

Next, the specific operation of one embodiment of the present invention will be described with reference to FIGS. 4 to 6. During normal playback, when a pause command signal is given from the mode control circuit 18 to the special playback control circuit 75,
Capstan drive direction forward/reverse mode switching circuit 75a
gives a reversal command signal to the capstan motor drive circuit 24d. At the same time, a temporary stop command signal is applied to brake command circuit 75c, and a brake control signal is applied to inverting amplifier 24b via OR gate 75j and switching transistor 75f, making it non-conductive. Therefore, the speed control signal is no longer given from the rotational speed control circuit 24a to the drive circuit 24d, and the capstan motor 13
A strong braking force is applied to rapidly reduce the rotational speed of the capstan 12. Then, the rotation direction detector 73 detects the rotation direction of the capstan motor 13, and a detection signal 74 is given to the rotation speed detection circuit 75i. When the rotation speed becomes less than or equal to a predetermined number, the rotation speed detection circuit 75i provides a detection signal to the capstan drive stop command circuit 75b. The capstan drive stop command circuit 75b is connected to the rotational speed detection circuit 7.
When the detection signal is given from 5i, the temporary stop command signal given from the mode control circuit 18 is
It is applied to the drive circuit 24d via the switching transistor 75d. The drive circuit 24d stops the capstan motor 13 based on the temporary stop command signal. Therefore, the capstan 12 quickly changes from the low speed normal rotation mode to the stopped state.

Note that if the rotational direction detector 73 generates two continuous pulses with a phase shift of, for example, 90 degrees as its output, the signal will not only have information on the rotational direction but also information on the rotational speed. Since the above-mentioned speed detection is also necessarily included, the speed detection described above can be easily achieved. Further, it is clear that the detection signal of the rotational direction detector 73 can be obtained by any configuration as long as it has such two pieces of information.

Next, a case will be described in which the state of high-speed forward rotation is shifted to a temporary stop mode. When the high-speed normal rotation command is released, the brake command circuit 75c
A brake control signal is given to the drive circuit 24d from the forward/reverse mode switching circuit 75a for the capstan drive direction, and a capstan drive direction reversal command signal is given to the drive circuit 24 from the capstan drive direction forward/reverse mode switching circuit 75a. As a result, a strong braking force is applied to the capstan motor 13, and the rotational speed of the capstan 12 is rapidly reduced. The subsequent operation is exactly the same as when changing from the normal playback mode to the pause mode described above.

Next, the operation when moving from the high-speed reverse mode to the temporary stop mode will be explained. In this case, in the same way as when changing from high-speed forward rotation mode to temporary stop mode, a brake control signal and a capstan drive direction reversal command signal are given to the motor control circuit 24 as the high-speed reverse rotation command is released, and the capstan 12 The rotation speed of the engine suddenly decreases. However, in this case, since the capstan 12 is rotating in the opposite direction, it goes without saying that the reverse command has the opposite polarity as in the case of normal reproduction and stopping from high-speed normal rotation. When the rotational speed of the capstan 12 becomes lower than a predetermined speed in the reverse mode, the rotational speed detection circuit 75i detects this. However, since the direction determination circuit 75h detects the reverse rotation of the capstan 12, the capstan drive stop command circuit 75
d does not issue a drive stop command signal. Therefore,
The brake command signal and reversal command signal are maintained as they are. Then, the capstan 12 passes through the stopped state and reverses in the forward direction. Then, the rotation direction determining circuit 75h detects this. At this time,
Since the rotational speed of the capstan 12 is still sufficiently low, the rotational speed detection circuit 75i continues to detect that the rotational speed is below the predetermined speed. Therefore, the output signal of the capstan drive stop command circuit 75b immediately makes the switching transistor 75d conductive. The drive circuit 24 stops the capstan motor 13. Therefore, capstan 1
As shown in FIG. 6a, the motor 2 quickly changes from a very low speed normal rotation mode to a stopped state.

As described above, according to this embodiment, the rotational speed of the capstan 12 is detected, and when the rotational speed falls below a predetermined number, the motor 13 is stopped, and moreover, when moving to the stopped state, the motor 13 is always stopped from the forward rotation state. Therefore, the problem that the tape 4 becomes loose between the supply reel 3 and the capstan 12 can be solved. Therefore, the contact between the video head 23 and the tape is good, and image distortion does not occur.

In the above embodiment, the rotational speed is detected based on the detection signal of the rotational direction detector 73, but the same effect as described above can be obtained without detecting the rotational speed. That is, the method shown in FIGS. 5b and 5c. That is, in the direction shown in FIG. 5b, when the capstan motor 13 reverses in the opposite direction when the normal regeneration and high-speed normal rotation regeneration are brought to a stop state, the brake command is released. And a capstan drive direction forward/reverse mode switching circuit 7
When 5a gives a reversal command signal to the capstan motor drive circuit 24d, the capstan 12 is further reversed in the forward direction. The direction discrimination circuit 75h detects this, and in combination with the temporary stop command signal and the information that the brake has already been released, the capstan drive stop command circuit 75b conducts the switching transistor 75d to switch the capstan. Stop the motor 13. This also applies when stopping from high-speed normal rotation playback and high-speed reverse rotation playback. In other words, when the two pieces of information "the brake has been released" and "the capstan 12 has reversed in the forward rotation direction" are satisfied, the capstan motor 13 immediately stops, thereby quickly and reliably achieving the paused state. can be realized.

Furthermore, since the rotational speed of the capstan 12 during normal playback is regulated, if the strength and application time of the braking force are set in advance, the braking force will first cause the capstan 12 to rotate as shown in Figure 5c. By rapidly reducing the speed to a predetermined value and then stopping the capstan motor 13, it is possible to quickly stop the normal rotation mode.

In this way, according to the method shown in FIGS. 5b and 5c, the detection signal 74 of the rotational direction detector 73 does not require the capstan rotational speed detection circuit 75i and does not include speed information. The same effect as shown in a can be obtained.

As described above, according to the present invention, by detecting the rotating direction of the capstan, it is possible to apply braking force to the motor that drives the capstan, thereby shortening the time it takes for the capstan to stop. Moreover, since the magnetic tape is always stopped from the normal rotation state, it is possible to prevent the magnetic tape from sagging between the supply reel and the capstan, thereby preventing image distortion. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing the overall structure of a VTR, which is the background of the present invention. FIG. 2 is a concrete block diagram showing a capstan control system for achieving a temporary stop in a conventional VTR. FIG. 3 is an illustrative diagram showing temporal changes in the rotational speed of a capstan in a conventional VTR. FIG. 4 is a schematic block diagram showing the overall structure of an embodiment of the present invention. FIG. 5 is a specific block diagram showing the capstan control system. 6th
The figure is an illustrative diagram showing temporal changes in the rotational speed of a capstan according to an embodiment of the present invention. In the figure, 12 is a capstan, 13 is a capstan motor, 24 is a control circuit, 24b is an inverting amplifier, 24d is a capstan motor drive circuit,
73 is a rotation direction detector, 75 is a special regeneration control circuit, 75a is a capstan drive direction forward/reverse mode switching circuit, 75b is a capstan drive stop command circuit, 75c is a brake command circuit, 75d, 75
e, 75f is a switching transistor, 75h
75i is a rotational speed detection circuit, and 18 is a mode control circuit.

Claims (1)

[Scope of Claims] 1. A magnetic recording tape that includes a capstan and a motor that rotates the capstan in a forward or reverse direction, and that reproduces a magnetic recording tape by running it in the forward or reverse direction according to the rotation of the capstan. The recording/reproducing device comprises: a pause command means for giving a pause command; and when the motor is rotating in a reverse direction, in response to a pause command being given from the pause command means. , a motor drive means for rotating the motor in the forward direction; and a motor stop means for stopping the motor when the rotation direction of the capstan is the forward direction and the rotation speed reaches a predetermined rotation speed. A magnetic recording and reproducing device. 2. The motor stopping means further includes rotational direction detection means for detecting a rotational direction of the capstan, and the motor stopping means detects that the capstan is rotating in the forward direction and stops the rotation of the capstan. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the motor is stopped when the speed reaches a predetermined number of rotations. 3. The motor stopping means further includes rotational speed detection means for detecting the rotational speed of the capstan, and the motor stopping means detects that the rotational direction detection means detects that the capstan is rotating in the forward direction and detects the rotational speed. 3. The magnetic recording and reproducing apparatus according to claim 2, wherein the means stops the motor in response to detecting the predetermined number of rotations. 4 Further, a braking force is applied to the capstan in response to a temporary stop command being given from the temporary stop command means, and a braking force is applied based on the motor being rotated in the forward direction by the motor driving means. The motor stopping means is configured to stop the motor based on the fact that the rotational direction detecting means detects the forward direction and the braking force is released by the braking force. A magnetic recording/reproducing device according to claim 2.