JPH064938U - Tape running device - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress the tape resonance amplitude generated in the tape running system. A yoke 15 is provided on the lower surface of a roller 14 that comes into contact with the tape and rotates following the tape, and a magnet 16 that faces the yoke 15 is provided on the chassis 12. The magnetic attraction between the magnet 16 and the yoke 15 makes it possible to exert a damper effect on the magnetic tape running system and suppress the amplitude due to resonance of the magnetic tape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tape running device used in a video tape player, an audio tape player, etc., and more particularly to a tape running device having improved efficiency of suppressing longitudinal vibration of a tape in a tape running system.

[0002]

[Prior art]

 A conventional example will be described with reference to the drawings. FIG. 6 is a schematic plan view showing a tape running device used in a video tape player. In the tape running device shown in FIG. 6, a tape T drawn from a tape reel 8 loaded on a supply-side reel stand 10a passes through a post P, an impedance roller 1, a loading roller 2a, and a rotary head having a magnetic head H. The tape is wound around the apparatus S, further held between the capstan 4 and the pinch roller 3 via the loading roller 2b and the post P, and wound around the tape reel 9 loaded on the winding side reel stand 10b.

The tape running speed is determined by the rotational force of the capstan 4, and the tape T running at this predetermined speed is wound on the tape reel 9. The tape running system is provided with a full-width erasing head 5, a voice erasing head 6 and a voice / control head 7 as fixed heads.

[0004]

[Problems to be solved by the device]

 In the above tape running device, the elasticity of the magnetic tape T is increased between the position A where the magnetic tape T is ejected from the tape reel 8 on the supply side and the point B where it is sandwiched between the capstan 4 and the pinch roller 3. A vibration system based on the coefficient is formed, and when the tape is running, there is a problem that resonance frequency of the vibration system causes the magnetic tape T to expand and contract in the tape length direction. The vibration in the expansion / contraction direction of the magnetic tape affects the read signal as jitter in the magnetic head H that reads the video signal and the like by rotating together with the rotating drum of the rotating head device S. The impedance roller 1 is provided as a countermeasure against this resonance. As shown in FIG. 7, the impedance roller 1 is provided so as to be freely rotatable with a predetermined mass, and comes into contact with the magnetic tape T to follow the running of the magnetic tape T and freely rotate.

FIG. 8 shows an equivalent model of the vibration system of the magnetic tape T. The elastic coefficient K in this model mainly relates to the elastic coefficient of the magnetic tape T. Although a load such as tension is applied to the magnetic tape T, the load mass M in the vibration system is increased by providing the impedance roller 1. By increasing the load mass M, the resonance frequency in the vibration system is lowered. That is, the jitter of reading by the magnetic head H of the rotary head device becomes a problem at a high reproduction frequency, and is increased by providing the impedance roller 1 and reducing the resonance frequency of the vibration system of the magnetic tape T. The influence of jitter on the playback frequency is minimized.

However, since the rotating mass of the impedance roller 1 has a limit, even if the impedance roller 1 is provided, the resonance of the tape itself cannot be suppressed, and there is a limit in improving the reproduction accuracy. In order to further improve the problem of the jitter, not only is the load mass M of the impedance roller 1 increased in the vibration system from the position A to the position B of the magnetic tape T, but the equivalent of FIG. If the vibration viscosity coefficient C shown by the broken line in the model is given, the amplitude of resonance itself can be attenuated. As a means for giving this viscosity coefficient C, for example, an oil damper or the like may be provided between the impedance roller 1 and its supporting shaft 1a, but the damper which gives a viscous resistance in the rotating direction of the roller has a structure. It becomes complicated and large, and problems such as temperature characteristics and oil leakage will occur.

The present invention solves the above-mentioned conventional problems, and a viscous coefficient can be given to the vibration system in the magnetic tape traveling path with a simple structure, and the amplitude of resonance in the expansion / contraction direction of the magnetic tape can be suppressed. It is an object of the present invention to provide a tape running device as described above.

[0008]

[Means for Solving the Problems]

 In the tape running device according to the present invention, a rotating body that rotates following the running of the tape is provided in the running path of the magnetic tape, and a damping force of vibration due to magnetism is applied to this rotating body. It is a feature.

Further, there is provided a rotary mass coaxial with the axis of the rotary body and capable of rotating independently of the rotary body, and the rotary body and the rotary mass are magnetically attracted to each other. .

[0010]

[Action]

 According to the above means, a load due to magnetic attraction is applied to a rotating body such as an impedance roller provided on the tape running path. The magnetic load on a moving object is proportional to the traveling speed due to the Lorentz force. Therefore, the load resistance due to this magnetic force is the same as that when the viscous coefficient C is given in the equivalent model of the vibration system in FIG. Given this, it is possible to suppress the amplitude of the expansion and contraction direction of the tape at the time of resonance, and to suppress the occurrence of the reproduction signal jitter itself due to the magnetic head.

In the second means, a rotary mass that rotates coaxially with the rotating body is provided. When the rotating body rotates following the running of the magnetic tape, the rotating body and the magnetically attracted rotating mass also rotate together. This rotating mass tries to rotate at a constant speed due to the moment of inertia. Therefore, when vibration is generated on the magnetic tape T and uneven rotation of the rotating body is about to occur, a resistance force similar to the above-mentioned viscosity is applied to the rotating body by the moment of inertia of the rotating mass, and the rotating unevenness of the rotating body is caused. Is suppressed, and the resonance amplitude of the tape is suppressed.

[0012]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings. 1 to 5 are cross-sectional views showing an impedance roller of the present invention according to each embodiment. The impedance roller shown in each of these embodiments comes into contact with the magnetic tape T and rotates following the magnetic tape T in the tape traveling path of the rotary head type shown in FIG. 6, for example. The impedance roller 11 of the first embodiment shown in FIG. 1 includes a roller (rotating body) 14 that comes into contact with the tape T, and a yoke 15 made of a magnetic material that is integrally fixed to the lower surface of the roller 14. A shaft 13 fixed to the chassis 12 is rotatably supported. A magnet 16 is provided on the chassis 12 so as to face the yoke 15 with a minute gap G therebetween.

In the tape running device provided with the impedance roller 11, in the vibration system from the position A to the position B in FIG. 6, the rotational mass of the roller 14 and the yoke 15 is the vibration equivalent model shown in FIG. Exerts the function of increasing the mass M of. Further, the rotating yoke 15 is always attracted by the magnetic force by the magnet 16 which is fixed. Since this magnetic resistance force is proportional to the rotation speed of the yoke 15, it is equivalent to giving the viscosity coefficient indicated by C in FIG. 8, and this magnetic force changes from position A to position B in FIG. Amplitude is suppressed in the vibration system up to the position.

In the impedance roller 21 of the second embodiment shown in FIG. 2, a yoke 25 made of a magnetic material and having a diameter larger than the outer peripheral portion of the roller 14 is fixed to the lower surface of the roller 14. A magnet 26 is provided on the chassis 12 side so as to sandwich the outer peripheral portion of the yoke 25 from above and below. The magnet 26 may have a U-shaped cross section as shown in FIG. 2, or the yoke 25 may be formed on one or both of the upper and lower inner surfaces of the U-shaped fixed yoke. You may provide the magnet which sandwiches.

In the impedance roller 31 of the third embodiment shown in FIG. 3, the magnet 16 is integrally fixed to the lower surface of the roller 14 with a yoke 25a made of a magnetic material interposed therebetween. Further, a ring-shaped yoke 25 having a U-shaped cross section is provided on the chassis 12 side so as to surround the magnet 16. The yoke 25 may be a flat surface facing the magnet 16. In this embodiment, the stationary side is the yoke and the rotating side is the magnet, but the vibration suppressing function is the same as that shown in FIG. A magnet 16 is provided below the roller 14 that contacts the magnetic tape, but the magnetic flux extending upward from the magnet 16 is collected by the yoke 25a, so that it does not affect the magnetic information on the magnetic tape. ..

The impedance roller 51 of the fourth embodiment shown in FIG. 4 is provided with a shaft 53 having a male screw portion 53 a at the lower end portion, and the shaft 53 is fixed to the roller 14 and the lower surface of the roller 14. A magnetic yoke 15a and a magnet 16 are rotatably supported. A yoke 15 is fixed to the chassis 12. The male screw portion 53a at the lower end of the shaft 53 is screwed to a female screw member 52a fixed to the chassis 12, and is further prevented from coming off by a nut 52b. In this embodiment, by loosening the nut 52b and rotating the head portion of the shaft 53, the gap G between the yoke 15 and the magnet 16 can be adjusted, and adjustment can be performed so that the optimum amplitude suppressing force acts. It has become. The fact that the resistance force can be adjusted by adjusting the facing gap G in this way is one of the characteristics of the damping device that uses magnetic force. In FIG. 4, the same applies to the yoke on the rotating side and the magnet on the chassis side.

In the impedance roller 41 of the fifth embodiment shown in FIG. 5, a yoke 15 made of a magnetic material is fixed to the upper surface of a roller 14 rotatably provided on a shaft 43. A bush 44 is screwed onto the upper portion of the shaft 43, and the magnet 16 serving as a rotating mass is rotatably mounted on the bush 44. A facing gap between the magnet 16 and the yoke 15 is set by a spacer 47. In this embodiment, the roller 14 and the magnet 16 rotate independently. When the roller 14 and the yoke 15 rotate as the tape runs, the magnet 16 magnetically attracted to the yoke 15 follows and rotates. Here, when the roller 14 has uneven rotation due to vibration in the expansion / contraction direction of the magnetic tape, the same action as the viscosity coefficient C shown in FIG. 8 is exerted between the magnet 16 and the yoke 15 which are used for rotation due to inertial force. A force for restraining the relative rotation works, and the roller 14 tries to rotate at a constant speed, so that the resonance of the tape is suppressed. On the contrary, a magnet 16 may be provided on the roller 14 side so that the yoke 15 can be independently rotated as a rotating mass. In order to improve the vibration suppressing function in this embodiment, it is preferable to make the mass of the magnet 16 or the yoke 15 rotating independently of the roller 14 as large as possible.

In each of the above embodiments, the resistance force is applied to the impedance roller 21 and the like by the magnetic force, but the magnetic resistance force may be applied to another rotating body such as the supply reel stand 10a. Further, in the illustrated embodiment, the tape running device using the rotary head device S is shown, but the present invention can also be applied to a tape running device using a fixed magnetic head, for example.

[0019]

[Effect of device]

 As described above, according to the present invention, magnetic resistance is applied to the rotating body located in the tape running system such as the impedance roller, so that the resonance amplitude of the vibration system due to the elastic coefficient of the magnetic tape is suppressed and jitter It becomes possible to prevent the deterioration of.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an impedance roller according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an impedance roller according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing an impedance roller according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing an impedance roller according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing an impedance roller according to a fifth embodiment of the present invention.

FIG. 6 is a plan view showing a conventional tape running device used in a video tape player.

FIG. 7 is a perspective view showing a conventional impedance roller.

FIG. 8 is an equivalent model explanatory diagram of a vibration system formed in a tape running portion.

[Explanation of symbols]

1, 11, 21, 31, 41, 51 Impedance roller 3 Pinch roller 4 Capstan 12 Chassis 13 Shaft 14 Roller 15 Yoke 16 Magnet G Gap S Rotating head device T Magnetic tape

Claims (2)

[Scope of utility model registration request] 1. A tape running characterized in that a rotating body which rotates following the running of the tape is provided in a running path of the magnetic tape, and a damping force of vibration due to magnetism acts on the rotating body. apparatus. 2. A rotating mass coaxial with an axis of the rotating body and capable of rotating independently of the rotating body is provided, and the rotating body and the rotating mass are magnetically attracted to each other. Tape drive device.