JPS63291248A - Method and device for driving tape - Google Patents

Abstract

PURPOSE:To prevent the generation of the twist and elongation of a thin tape by transferring a tape by touching to the tape with a face contact on the whole by the surface wave of a vibration body. CONSTITUTION:Tape transfer parts 1, 2, i.e., tape driving device is composed by arranging a set of piezoelectric elements 11, 12 on which the alternate voltage of different phase is impressed by alternate power sources Ea, Eb on a supporting body 10 by adjoining each other a lot. And a progressing wave (surface wave) is generated on the surface of the piezoelectric element groups 11, 12 and by bringing a tape 4 into pressurized contact with this surface it is transferred by giving to the tape 4 a vibration in the reverse direction to the progressing direction of the surface wave. The twist and meandering of the tape is thus prevented to enable a stable traveling even in the case of a thin tape by driving the tape with vibration.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a novel method and device for driving a tape in a tape running system such as a magnetic tape. The present invention provides a tape driving method and apparatus which generates a surface wave by ultrasonic vibration and uses the surface wave to drive the tape, which is particularly suitable for thin tape.

(Prior art and problems to be solved by the invention) VT
Capstans and pinch rollers that are rotated at a constant speed by a motor are conventionally used to run magnetic tape in R and tape recorders.
If the tape is thin, the tape may become kinked or meander, which may impede stable running. In addition, there have been cases where the tape has been stretched by the tensioner, but if the tape is stretched, the position of the head cylinder that records and plays back signals is far from the position of the capstan that drives the tape, so there is a risk that precise tracking will not be possible. This was an inconvenience.

In view of the drawbacks of the conventional tape drive system using capstans and pinch rollers, the present invention aims to provide a completely new drive method and device that eliminates the above drawbacks by driving the tape with vibration. This is the purpose.

(Means and effects for solving the problems) The present invention generates a unidirectional traveling surface wave by ultrasonic vibration on the surface of a vibrating body, and presses this surface against the surface of the tape in the tape running system. It is characterized by transporting the tape in the direction opposite to the traveling direction of the surface waves, and uses an electrostrictive element or a magnetostrictive element as the vibrating body.

Surface waves (
Ultrasonic motors are known as devices that generate bending vibrations (for example, Applied Physics Vol. 54, No. 6, pp. 65-66, published in 1985, Nikkei Mechanical 1986, 3,
No. 24, p. 40, Nikkei Electronics 1986゜3.2
No. 4, pages 90-92, same magazine 1987.3.9 No. 86-87
The present invention applies the principle of this ultrasonic motor.

According to this WL theory, the vertices of a large number of surface waves generated on the surface of a vibrating body vibrate ultrasonically in an elliptical trajectory, come into contact with a moving body placed on the surface, and I! J-rubbing allows a moving object to move in the opposite direction to the direction of travel of the wave.

The present invention drives a tape by bringing a vibrating body having such surface waves into surface contact with the tape.

A tape drive device that applies the principle of this ultrasonic motor is
A unidirectional traveling wave is generated on the surface of an elastic body by applying vibrations using multiple vibrators to which high-frequency voltages with a phase shift of 90° or 120° are applied to a vibrating body in contact with the tape, but in direct contact with the tape. The vibrating body is not an elastic body separate from the vibrator, but is composed of a large number of piezoelectric elements arranged adjacent to each other, and by alternately applying alternating voltages with different phases to the piezoelectric element group, the piezoelectric element A traveling wave may be generated on the surface of the group.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 schematically shows an application example of the tape driving method and apparatus according to the present invention, in which a pair of tape transport sections 1.2 are
They are arranged on both front and rear sides of the rotating drum unit 3 equipped with a TR magnetic head, and the VTR tape 4 is accurately fed by a tape transfer i51 on the downstream side of the rotating drum, and a tape transfer s2 on the upstream side of the rotating drum. It gives puck tension to the tape. The pair of reels 5 and 6 are provided with a driving force such that the tape downstream reel 5 winds up the tape 4, and the upstream reel 6 applies a light pack tension to the tape 4, similar to ordinary reels.

The tape transport unit 1.2, that is, the tape drive device according to the present invention, is connected to an alternating power supply Ea as shown in FIGS. 2A and 28, for example.
, Eb, a plurality of piezoelectric element groups 11, 12 to which alternating voltages of different phases are applied are alternately adjacent to the support 1.
0, which generates traveling waves (surface waves) on the surfaces of the piezoelectric element groups 11 and 12.
By bringing the tape 4 into pressure contact with this surface, the tape 4 moves in the direction of movement at the top position of each apex on the surface, which is vibrating elliptically in the opposite direction to the traveling direction of the surface wave due to the above-mentioned principle. be transported.

FIG. 3 shows another version of the tape drive device according to the present invention, which has a piezoelectric element 21 on the back side of one elastic body 20.
is fixed, the tape 4 is pressed against the surface of the elastic body 20, and the piezoelectric element 21 applies high frequency vibration to the elastic body 20, thereby generating a unilateral traveling surface wave on the surface of the elastic body 20 and transferring the tape 4. .

FIG. 4 shows yet another embodiment, in which a pair of vibrators 31 and 32 for applying high frequency vibrations with a phase difference of 90° are arranged at both ends of a 1M elastic body 30.
A vibration absorber 33 is connected to one end of the vibration absorber 33 to prevent a reflected wave from being generated at one end and becoming a standing wave as a whole.

FIG. 5 shows an example in which these tape transport sections are provided directly on the cylinder 7.8 of the rotating drum section of the VTR tape 4 running system. A rotary head 9 is provided to rotate between the pair of cylinders 7 and 8, but the rotary head 9 is attached to a part of one cylinder 7 and the other cylinder 8 is fixed. A piezoelectric element group as described above is provided on at least a portion of the tape transfer surface of the fixed cylinder 8. In addition, as shown in FIG. 6, in a case where both of the pair of cylinders 7' and 8' are fixed and a rotary head section 9 is interposed between them, both cylinders 7' and 8' have piezoelectric element groups 40.
1 will be provided. The piezoelectric element groups 40 and 41 are composed of a large number of piezoelectric elements arranged alternately in the traveling direction of the tape 4, but each of them is not shown. What is shown in the figure as being arranged in large numbers in parallel are different piezoelectric element groups, each of which generates a surface wave that propagates in the length direction.

FIG. 7 shows an example in which the tape drive *@rfl of the present invention is employed in an audio cassette 50, in which a pair of tape transport sections 51 and 52 are disposed with the portion that corresponds to the magnetic head sandwiched therebetween.

Needless to say, the driving force for the tape is changed between the transfer section 51 that drives the tape and the transfer section 52 that applies pack tension to the tape, and this function is similar to that of conventional rollers etc. .

In each of the above embodiments, piezoelectric elements are typically used, but the present invention applies the principle of an ultrasonic motor to tape transport, and mechanically converts electricity from electrostrictive elements, magnetostrictive elements, etc. Needless to say, any device can be used with any modifications made to the details as long as it generates a traveling surface wave using an element that converts into vibration.

(Effects of the Invention) According to the tape driving method and device of the present invention, since the tape is transported by contacting the tape as a whole in a surface-contact manner using the surface waves of the vibrating body, the tape is locally strong. No tensile force is applied, and even if the tape is thin, it can be prevented from twisting or stretching, and stable tape feeding can be achieved.

In addition, since the motor that is conventionally used to drive the capstan is not used, space is saved, the position of the tape drive unit can be freely selected, and the entire tape drive system is made smaller and lighter. It will also be possible to realize this.

Furthermore, by driving with ultrasonic vibration using a piezoelectric element or the like, the tape can be transported with high precision of less than 1 μm J:X, and the responsiveness is also good.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing an embodiment of a tape running system of a VTR using the tape drive system of the present invention, and FIG. 2A is a side view of an example of a tape drive device used in the embodiment. 2B is a plan view thereof, FIG. 3 is a perspective view showing another example, FIG. 4 is a plan view showing a further different example, and FIG. FIG. 6 is a side view showing another embodiment, and FIG. 7 is a schematic plan view showing an example of a tape drive system of an audio cassette employing the tape drive device of the present invention. 1.2.51.52... Tape transfer section 3... Rotating drum section 4... Magnetic tape 5.6... Reel 7.8... Cylinder 9... Rotating magnetic head 11.12 ...Piezoelectric element Figure 1
Figure 2A Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1) A tape driving method characterized in that a unidirectional traveling surface wave is generated by ultrasonic vibration on the surface of a vibrating body, and the tape is transferred by bringing this surface into pressure contact with the tape. 2) A tape comprising a vibrating body disposed in pressure contact with the surface of the tape in a tape running system, and means for generating a surface wave that propagates in the length direction of the tape in contact with the tape contacting surface of the vibrating body. Drive device.