JP3369789B2 - Magnetic recording / reproducing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to tape feeding in a magnetic recording / reproducing apparatus such as a video tape recorder (hereinafter referred to as VTR), and more particularly to ultra-low speed tape feeding.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus such as a VTR, in addition to the normal recording / reproducing mode, high-speed tape feeding,
A special playback mode such as low speed feeding is an indispensable function, and generally several kinds of tape feeding speeds are provided. At the time of normal recording / reproduction in a VTR, a magnetic tape is sandwiched between capstans and a pinch roller is pressed against them.
It is a general method to drive the tape by running a direct drive motor directly connected to the capstan at a predetermined rotation speed.

For high-speed tape feeding such as "fast tape feeding" and "tape rewinding", the reel stand on the take-up side or the supply side is rotated at high speed without passing through the capstan, and the tape is moved at high speed. A winding mechanism is often provided. The tape speed in “CUE”, “REVIEW”, etc. is about several times the normal playback speed, and it is necessary to send the tape at a constant speed due to the noise on the screen.
A method is adopted in which the capstan is rotated at a predetermined speed, the tape is held between the capstan and the pinch roller, and the tape is run.

On the other hand, for low speed feeding such as "slow reproduction", the tape is sandwiched between the capstan and the pinch roller is brought into pressure contact with the capstan, and the capstan is 1 / N (N) of the normal reproduction speed, as in the normal recording / reproduction. Is an integer) and is rotated at a low rotation speed, and the tape is fed at a low speed.

[0005]

Apart from the above-mentioned "fast-forward tape" and "rewind tape", "CUE", "R"
In modes such as "VIEW" and "slow playback", the tape speed needs to be constant, and for that purpose, the capstan motor is required to be controlled accurately. The general characteristics of the motor are "CUE" and "RE".
It is relatively easy to control the number of revolutions during high-speed tape feeding such as "VIEW", but it is difficult to control the number of revolutions at an ultra-low speed such as "slow reproduction". Further, in order to obtain a certain torque or more required for tape feeding, the number of rotations of the direct drive motor is limited, and it is not possible to satisfy the demand for rotating the direct drive motor infinitely slow.

As described above, in a VTR equipped with a general tape feeding mechanism for rotating a capstan with a direct drive motor, the tape speed at the time of low-speed tape feeding is naturally limited, so that a low-speed feeding such as "slow reproduction" is performed. It is difficult to add uniqueness to the special playback function. In particular, digital VTRs, which are expected to grow in the future, are expected to have various possibilities in signal processing because they are digital, but if the tape feed speed is limited,
This is a major obstacle to the development of special playback functions.

[0007]

Therefore, in the present invention, in a magnetic recording / reproducing apparatus for feeding a tape by a capstan and a pinch roller, a direct drive type first motor having a capstan attached to a rotor and a deceleration The second motor is provided with a driving force transmission means that comes into contact with and separates from the rotor via a mechanism, and the capstan is selectively driven by the first or second motor according to the tape running mode. To make the configuration.

Further, the first motor is provided with a rotation speed detection means, and the rotation signal of the rotation speed detection means is used to control the rotation of the second motor. Also, as the driving force transmission means,
It is composed of a transmission gear that meshes with a gear portion provided on the rotor. Or, it is composed of an idler that is pressed against the rotor.

[0009]

With the above structure, in the normal recording / reproducing mode, the tape is sandwiched between the capstans and the pinch rollers are brought into pressure contact with each other, and the direct drive type first motor having the capstans is driven to drive the tapes. Run at a constant speed. Further, during slow reproduction, when the second motor is driven while the tape is sandwiched between the capstan and the pinch roller in pressure contact, the transmission gear as the driving force transmission means meshes with the rotor gear portion of the first motor. The driving force of the second motor causes the capstan to rotate at a predetermined number of rotations via the speed reduction mechanism, so that the tape runs at an extremely low speed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a mechanism showing a tape running system, FIG. 2 is a side sectional view of a main part, and FIG. 3 is a circuit block diagram. In FIG. 1, 1 is a cassette having a supply-side reel 2 and a winding-side reel 3, 4 is a supply-side tape pull-out guide, 5 is a take-up-side tape pull-out guide, 6 is a back tension post, and 7 is a vertical guide 8 and an inclination. A leading guide block on the supply side for drawing out the tape T from the cassette 1 equipped with a guide 9 is an inclined guide 1
1 is a direct drive motor having a winding guide guide block for pulling out the tape T from the cassette 1 and a vertical guide 12, 13 is a cylinder, 14 is a fixed guide, and 15 is a rotor 17 to which a capstan 16 is integrally fixed. Motor 18), 18 is a pinch roller, and 19 is a rotation detecting sensor composed of a magnetoresistive element which is arranged on the outer periphery of the rotor 17 so as to face a magnet (not shown) having S and N poles alternately magnetized.

Referring to FIG. 2, reference numeral 20 is a sub motor (second motor) having a motor gear (or pulley) 21 integrally fixed thereto, and 22 is a reduction mechanism. The speed reduction mechanism 22 is composed of two-stage gears 24, 25, 26 rotatably supported by shafts 23a, 23b, 23c on a chassis 23, and a transmission gear (may be a pulley) 27. The transmission gear 27 is a lever 2 rotatably supported by a shaft 23c.
8 is rotatably supported by a shaft 28a and is in constant mesh with the small gear 26a of the two-stage gear 26.

Next, the operation of the present invention will be described. When the button of the keyboard 31 (see FIG. 3) is operated (for example, the play button is pressed), the tape T is first pulled out of the cassette 1 by the guides 4 and 5. After that, the leading guide blocks 7 and 10 further pull out the tape T, and the predetermined angle tape T is wound around the linder 13. Along with this, the back tension post 6 comes into contact with the tape T to be in a tape tension detection position, and the pinch roller 18 presses the capstan 16 while sandwiching the tape T to form the tape running path shown in FIG.

In a normal recording or reproducing mode, a system control microcomputer (hereinafter referred to as "syscon") 32 is operated by a servo circuit 33 by a command from a keyboard 31.
The capstan motor drive circuit 34 and the cylinder motor drive circuit 35 are operated via the to rotate the first motor 15 and the cylinder 13 at a predetermined rotation speed. At the same time, the rotation phase of the cylinder 13 is detected by the PG (pulse generator) detection head 36, and the output and the FG (Frequency Generator) pulse picked up by the rotation detection sensor 19 of the first motor 15, The control pulses detected from the control tracks of the tape T by the control head 37 are respectively input to the servo circuit 33, which are compared and adjusted with a reference signal (not shown) to perform phase / speed control, and the capstan motor drive circuit 34. By being fed back, the tape is run at a constant tape running speed.

In the modes such as "CUE" and "REVIEW", the direct drive motor 15 as the first motor is driven at a constant rotation speed according to the mode, and the rotation speed of the capstan is maintained at a constant rotation speed. Hold on to a number.
In the normal recording / playback mode described above, the second motor 20
Does not rotate, so the transmission gear 27 is
Is separated from the rotor 17. The configuration described above is no different from that of the known VTR.

Next, the "slow reproduction" which is a feature of the present invention
A description will be given of tape feeding at an extremely low speed such as. When slow playback operation is performed, the keyboard
2 and a signal from the syscon 32 drives a mode switching cam gear (not shown), and a mode switching member (not shown) interlocked with the cam gear causes the protrusion 28b of the lever 28 to move in the B direction (see FIG. 1) to engage the transmission gear 27 with the gear portion 17a of the rotor 17 of the first motor 15.

A signal from the syscon 32 activates the sub motor drive circuit 38 via the servo circuit 33 to rotate the second motor 20. The rotational driving force of the second motor 15 is transmitted to the rotor 17 via the speed reduction mechanism 22. The rotation detection sensor 19 detects the rotation frequency of the rotor 17, and the detection signal is input to the servo circuit 33, whereby the rotation speed of the capstan 16 is controlled. Even in the slow reproduction mode, the cylinder 13 is rotationally driven at a predetermined rotational speed via the cylinder motor drive circuit 35, the rotational phase of the cylinder 13 is detected by the PG detection head 36, and the rotational phase control of the cylinder motor is performed. Is made.

In order to realize an ultra-low speed tape feed such as the slow reproduction mode described above, the sub motor 2 is used as in the present invention.
When 0 is adopted, when the same low speed rotation speed is realized for the capstan 16 as compared with the case where the direct drive motor itself performs ultra-low speed tape feeding, the sub motor 20
The number of rotations of the sub motor 20 can be set to be large in proportion to the rotation reduction ratio. That is, if the reduction ratio is set large, the number of rotations of the sub motor 20 can be set large for the reduction ratio. As a result, a large torque is transmitted to the capstan 16, and it becomes possible to easily feed the tape at an extremely low speed. Further, since it is possible to further reduce the rotation speed of the sub motor 20, it is possible to easily obtain a tape feeding speed that is significantly slower than the minimum tape feeding speed obtained by the direct drive motor 15 itself. Therefore, it becomes possible to feed the tape at an extremely low speed, which is not possible with the conventional mechanism, and is a very effective means for adding the special reproduction function.

Further, as described above, in the slow playback mode,
Since the rotation detection sensor 19 of the direct drive motor 15 is also used as the speed control means of the sub motor 20, the rotation speed of the capstan 16 can be precisely controlled to a value that is directly required, so that the “slow reproduction” with high precision can be performed.
Will be possible. Furthermore, even in "intermittent slow playback" such as frame-by-frame playback, since the speed reduction mechanism is provided, the speed control of the sub motor 20 is facilitated, and the pad-type capstan brake required for the direct drive motor is unnecessary. Become.

The sub motor 20 in the configuration of the present invention is
Since durability is not required from the viewpoint of the frequency of user's usage called special reproduction, an inexpensive small brush motor is sufficient, and the reduction mechanism can be composed of an inexpensive gear.
When implementing the constitution of the invention, the cost does not increase significantly. In the configuration of the present invention, the gear portion 17a is provided on the outer circumference of the rotor 17 and the method of using the gear mechanism as the driving force transmission means of the sub motor 20 is described as an example. like,
It is also possible to use rotation transmission means other than gears.

[0020]

With the above structure, by providing a sub motor and a speed reduction mechanism in addition to the direct drive motor, ultra-low speed tape feeding can be realized with a simple structure and high accuracy. Since the VTR equipped with only the tape feeding mechanism having the known structure can achieve the extremely low speed tape feeding which cannot be realized, it is useful for developing the special reproduction function.

[Brief description of drawings]

FIG. 1 is a plan view of a mechanism showing a tape running system.

FIG. 2 is a side sectional view of a main part.

FIG. 3 is a circuit block diagram.

[Explanation of symbols] 15 Direct drive motor (first motor) 16 capstan 17 rotor 19 Rotation detection sensor 20 second motor 22 Reduction mechanism 27 transmission gear

Claims (4)

(57) [Claims] 1. A magnetic recording / reproducing apparatus for feeding a tape with a capstan and a pinch roller, wherein a direct drive type first motor having the capstan attached to a rotor and a rotor of the first motor are provided. A magnetic motor characterized by comprising a second motor for transmitting a driving force via a speed reducing mechanism that abuts / separates, wherein the capstan is selectively driven by the first motor or the second motor. Recording / playback device. 2. The magnetic recording according to claim 1, wherein the first motor is provided with detection means for detecting a rotation frequency detection, and the second motor is rotationally controlled by a detection signal of the detection means. Playback device. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the driving force transmission means is a transmission gear that meshes with a gear portion provided on a rotor of the first motor. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein the driving force transmitting means is an idler that is in pressure contact with the rotor of the first motor.