JPH09185858A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stable tape running by providing a couple of flanges guiding one edge of a magnetic tape and a couple of movable flanges depressing other edge of the magnetic tape so as to restrict the position of the magnetic tape in the broadwise direction. SOLUTION: A movable flange 69 whose one end is fitted to other end of a leaf spring 70 fixed to a guide 40 is energized in a direction of a flange 68 by the leaf spring 70. Thus, the flange 69 acts like pressing the magnetic tape 1 in a direction of the flange 68. A guide wall 41a, a flange 72 and a movable flange 73 fitted to a leaf spring 74 acting similarly to above are provided to a position nearly symmetrical with respect to the (z) axis. Thus, the movable flanges 69, 73 surely act on other edge 1b of the magnetic tape 1 to press the magnetic tape 1 toward the flanges 68, 72.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention attaches a magnetic head to a rotating body having a rotation axis in a direction substantially orthogonal to the surface of a magnetic tape, and the magnetic head is slidably contacted with the magnetic tape to form an arc-shaped recording track. And a magnetic recording / reproducing device for recording and / or reproducing.

[0002]

2. Description of the Related Art With reference to FIG.
The magnetic recording / reproducing method disclosed in Japanese Patent No. 2 will be described. In the figure, 1 is a magnetic tape, 2 is a rotating body having a rotation axis substantially orthogonal to the surface of the magnetic tape, and 3 is a motor for rotationally driving the rotating body 2. The magnetic head 4a,
4b are attached to these magnetic heads 4a, 4
.. are recorded or reproduced by slidingly contacting the magnetic tape 1. The arrow 5 indicates the running direction of the magnetic tape 1, and 6 and 7 indicate tape guides. The recorded track pattern has an arc shape as indicated by reference numeral 8 (see FIG. 2). Hereinafter, such a magnetic recording / reproducing method will be referred to as an “arc recording / reproducing method”, and the apparatus will be referred to as an “arc recording / reproducing apparatus”. This arc recording / reproducing apparatus is characterized in that it does not have a so-called lead (described later) for guiding the inclined pole or the edge of the magnetic tape when compared with a so-called helical scan type VTR apparatus. The regulation in the direction (width direction) depends on the guides 6 and 7.

FIG. 2 shows an example of a recording pattern on the magnetic tape surface recorded by the arc recording / reproducing apparatus as shown in FIG. As shown in the figure, the recording track is formed in an arc shape. The recording track form at this time is determined by the track width of the magnetic head, the number of magnetic heads attached to the rotating body 2, the number of rotations of the rotating body 2, the transfer speed of the magnetic tape 1, and the like. In the example of FIG. 2, a magnetic track pattern having a track width TRw ₁ is formed on the magnetic tape 1. In this example, a guard band that does not record a signal is formed between each track.
It is also possible to eliminate the guard band depending on the traveling speed, the rotation speed of the rotating body 2, the track width TRw _{1 of} the head, the number of mounted heads, and the like. In such a case, it is also effective to make adjacent tracks different azimuth angles in order to reduce crosstalk between adjacent tracks. The central angle θ ₁ of the arc formed by the magnetic heads 4a, 4b, ... Contacting the magnetic tape 1 is called the contact angle. Further, FIG. 2 shows a recording pattern of the principle model, in which the track width is displayed in an enlarged manner compared to the actual one.

FIG. 3 shows a so-called helical scan type apparatus which is generally used in a home VTR or the like. As is well known, the magnetic tape 31 is a magnetic head (not shown).
Is recorded and reproduced by being obliquely wound around the side surface of the rotating upper drum 32 by about 180 degrees. At this time, the magnetic tape 31 records a predetermined track pattern by running while the one edge 31a of the magnetic tape 31 is regulated by a shelf-shaped lead 34 formed on a fixed drum 33 provided below the upper drum 32. It has a structure that allows it. Tracking when reproducing a recording pattern according to this method is performed by controlling the running speed and position in the longitudinal direction of the magnetic tape. FIG. 4 shows a track pattern on the magnetic tape 31 by this helical scan type apparatus. The inclination angle θ _{2 of the} track recorded on the magnetic tape 31 is, for example, about 6 degrees in the VHS (registered trademark) system, and the VHS system EP mode (the magnetic tape is run at a speed of 1/3 of the standard mode). The track width TRw _{2 in the} long time mode) is 19 μm.

[0005]

In the arc recording / reproducing method as shown in FIG. 1, the recording pattern has an arc-shaped track centered on an axis substantially perpendicular to the magnetic tape 1 as shown in FIG. Since it is a mode in which the tape is sequentially formed in the direction, it is not sufficient to control the running speed and the position in the tape longitudinal direction for tracking during reproduction, and the position control in the width direction of the tape is more difficult than the helical scan method. More precise is required. Further, in the apparatus of FIG. 1, the leads 3 for regulating the magnetic tape width direction as shown in FIG.
It is difficult to install 4.

Now, let us consider a case of reproducing an arc pattern having a track width TRw ₁ as shown in FIG. The amount of track deviation ΔTRw ₁ when the magnetic tape 1 deviates from the original position with respect to the center of rotation of the rotating body 2 in the tape width direction is ΔTRw ₁ = d when the contact angle is θ _1. - represented by sin (θ _1/2). Where θ ₁ = 90 degrees, TRw ₁ = 19 μm
And d = 10 μm, ΔTRw ₁ = 7 μm,
The effective track width is greatly reduced to 12 μm. In order to reduce the decrease in the track width, a method of moving the rotating body 2 by this amount of displacement or a correction by moving the entire cartridge (not shown) accommodating the magnetic tape 1 may be considered, but it is mechanically complicated and expensive. I have no choice. On the other hand, in reproducing the recording pattern of the VTR of the helical scan system as shown in FIG. 4, the track tilt angle θ ₂ is about 6
10 μ in the width direction of the magnetic tape 31
The deviation of m can be said to be almost no problem because the position of the magnetic tape in the running direction can be controlled by moving it by about 100 μm as a reduction of the reproduction track width. As described above, the arc recording / reproducing method is mechanically inexpensive and simple, but
More precise tape running performance in the tape width direction is required.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the invention according to claim 1 is "magnetic in a rotating body having a rotating shaft in a direction substantially perpendicular to the magnetic tape surface. In a magnetic recording / reproducing apparatus in which a head is attached, and the magnetic head is slidably contacted with the magnetic tape to form an arc-shaped recording track for recording / reproducing, a surface of the magnetic tape is guided near both sides of the rotating body. A pair of surface guide members, a pair of edge guide members that guide one edge of the magnetic tape, and a pair of biasing members that press and bias the other edge of the magnetic tape. A magnetic recording / reproducing device that

According to a second aspect of the present invention, "A magnetic head is attached to a rotating body having a rotation axis in a direction substantially orthogonal to the magnetic tape surface, and the magnetic head is slidably contacted with the magnetic tape to form an arc-shaped recording track. In a magnetic recording / reproducing apparatus for forming and recording, a pair of surface guide members for guiding the surface of the magnetic tape near both sides of the rotating body, and the rotating body at a position substantially symmetrical to the rotation axis of the rotating body. The magnetic recording / reproducing apparatus is provided with a pair of edge guide means for guiding both edges of the magnetic tape against the couple generated by the rotation of the body. " And

According to a third aspect of the present invention, "a pair of biasing members that face the pair of edge guide means and press and bias the edge of the magnetic tape are further provided. The magnetic recording / reproducing apparatus according to claim 2. "

According to a fourth aspect of the present invention, "the gap between the pair of edge guide means in the width direction of the magnetic tape is set to be smaller than the width of the magnetic tape by a predetermined amount. Magnetic recording / reproducing apparatus. "

According to a fifth aspect of the invention, "the gap between the pair of edge guide means in the width direction of the magnetic tape is set so that the shear deformation applied to the magnetic tape is 0.2% or less. The magnetic recording / reproducing apparatus according to claim 4, "

According to the sixth aspect of the present invention, "the magnetic tape is disposed at a position spaced apart from the width of the magnetic tape by a predetermined distance from each of the pair of edge guides so as to face the pair of edge guides. 6. A magnetic recording / reproducing apparatus according to claim 4 or 5, further comprising: a restricting unit that restricts fluctuation of the edge portion of the magnetic recording / reproducing apparatus.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a rotary recording section 38 of a magnetic recording / reproducing apparatus of the present invention will be described with reference to FIGS. The rotation recording unit 38 is roughly composed of a rotating body 42, a motor 39 for driving the rotating body 42, and guides 40 and 41 provided on both sides of the rotating body 42. As shown in FIG. 6, the rotating body 42 has a surface whose cross-sectional shape is a substantially conical shape, and the magnetic head is attached to the windows 44 a and 44 b provided on the conical surface that contacts the magnetic tape 1. 45a and 45b are attached. Then, an arc recording pattern is formed on the magnetic tape by this magnetic head. In FIG. 5, the center of the tape width direction and the guide wall 40 of the guide 40
a and the central portion of the guide wall 41a of the guide 41 as an O point,
Passing point O, the x-axis is set in the tape running direction, the y-axis is set in the vertical direction on the tape surface, and the z-axis is set in the width direction. The tape running direction is indicated by an arrow 50, and the rotating direction of the rotating body 42 is indicated by an arrow 51. In the example of FIG. 5, two magnetic heads are shown.

In such a recording method, the rotating body 42 is usually rotated at a high speed to increase the relative linear velocity and increase the recording density. As a result, a phenomenon occurs in which the magnetic tape 1 is attracted to the conical surface 47 of the rotating body 42 between the conical surface 47 of the rotating body 42 and the magnetic tape 1 by Bernoulli's theorem. From this phenomenon, a couple M is generated on the magnetic tape 1 around the rotation axis of the rotating body 42. In order for the magnetic tape to travel stably in the x-axis direction due to mechanical equilibrium, a reaction force against this couple M is necessary. FIG. 6 shows a state in which the rotation recording section 38 of FIG. 5 is viewed from the z-axis direction. The rotary shaft 43 of the rotary body 42 is slightly tilted with respect to the y-axis which is a direction perpendicular to the magnetic tape surface, and this tilt angle is θ ₃ . The rotating body 42 includes a conical surface 47 that contacts the magnetic tape 1 and magnetic heads 45a and 45b.
Assuming that the apex angle of the conical surface 47 is θ ₄ , it is configured to have a relationship of approximately θ ₄ + 2 · θ ₃ = 180 °. In this state, the conical surface 47 contacts the magnetic tape 1 substantially parallel to the x-axis. The magnetic head 45 a, which is arranged so as to protrude by a predetermined dimension from the windows 44 a and 44 b provided on the surface 47, contacts the magnetic tape 1. At this time, the magnetic head 45b, which is located 180 degrees opposite to the magnetic head 45a, does not come into contact with the magnetic tape 1.

An embodiment of the present invention will be described below with reference to FIGS. 7 to 13. (First Embodiment) FIG. 7 is a perspective view showing a configuration around a rotary recording portion of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention. In the figure, 40a is a guide wall that slides on the surface of the magnetic tape 1 to guide the magnetic tape 1, and 68 is a flange that regulates the position of one edge 1a of the magnetic tape 1 and is integrally formed with the guide 40. There is. 69 is a guide 40 at one end
It is a movable flange attached to the other end of the leaf spring 70 fixed to, and is biased by the leaf spring 70 toward the flange 68. Therefore, the movable flange 69 has a function of pressing the magnetic tape 1 toward the flange 68. A guide wall 41 having a similar function is provided at a position substantially symmetrical with respect to the z axis.
a, a flange 72, and a movable flange 73 attached to the leaf spring 74 are provided. The guide wall 40a,
Although 41a is a fixed type in the drawing, it may be configured by using a roller.

The height of the guide wall 40a sandwiched between the flange 68 and the movable flange 69 and the height of the guide wall 41a sandwiched between the flange 72 and the movable flange 73 are the same as those of the magnetic tape 1.
Set it to be slightly smaller than the allowable minimum dimension value (minimum value of the variation range defined by the standard) for the width dimension of. Thereby, the movable flanges 69 and 73 reliably act on the other edge 1b of the magnetic tape 1 to press the magnetic tape 1 toward the flanges 68 and 72. As a result, even if the width of the magnetic tape 1 varies, the edge portion 1a of the magnetic tape 1 does not change.
The (lower end) is always used as a reference for guiding, and the tape running performance is satisfied. At this time, magnetic tape 1
The tape is given the required tension so that it does not buckle due to the forces acting on the edges of the tape.

(Second Embodiment) FIG. 8 is a perspective view showing a structure around a rotary recording portion of a magnetic recording / reproducing apparatus according to a second embodiment of the present invention. As described above, a couple is generated in the magnetic tape 1 by the rotation of the rotating body 42. This couple is applied to the running performance of the tape in this embodiment. Four
0a and 41a are guide walls formed on the guides 40 and 41, and 76 and 78 are flanges.
The y-z axis relationship is the same as above. Now, the rotating body 42
Is rotated, a couple M is generated on the magnetic tape 1 around the y-axis. In equilibrium, the reaction forces F ₁ and F ₂ are generated on the flanges 76 and 78. These forces F ₁ and F ₂ act as forces for pressing the magnetic tape 1 against the respective flanges 76 and 78. This indicates that the flanges 76 and 78 determine the positional relationship of the magnetic tape. However, at this time, it is assumed that the magnetic tape 1 is provided with an appropriate tension T so that buckling does not occur. Flange 7
The positional relationship between 6 and 78 is preferably symmetrical with respect to the y axis.

In this state, it can be understood that the magnetic tape 1 is sheared. At this time, both flanges 7
It can be seen that the center of the magnetic tape 1 regulated by 6, 78 always coincides with the point O even if a dimensional error occurs in the width direction of the tape. In this way, precise tape running performance in the tape width direction can be satisfied regardless of the tape width dimensional variation. In FIG. 8, the rotation direction of the rotating body 42 is set to the direction shown by the arrow 51, but in the opposite direction, the couple generated is also in the opposite direction, and the flange 7
The positions of 6 and 78 also need to be symmetrically related to the y-axis. The guide walls 40a and 41a are fixed types in the drawing, but may be configured by using rollers.
This is the same as in the embodiment.

(Third Embodiment) FIG. 9 is a perspective view showing a structure around a rotary recording portion of a magnetic recording / reproducing apparatus according to a third embodiment of the present invention. In the present embodiment, the couple acting on the magnetic tape 1 described with reference to FIG. 8 in the second embodiment is used, and the magnetic tape 1 with the leaf spring described with reference to FIG. 7 in the first embodiment is used. This is an example of applying the method for urging the. The structures of the guides 40 and 41 in this embodiment are substantially the same as those of the second embodiment. In this embodiment, the movable flange 91 is arranged so as to face the flange 76 of the guide 40. That is, the movable flange 91 has one end fixed to the other end of the leaf spring 92 fixed to the guide 40, and is biased toward the flange 76. Similarly, the movable flange 95 is arranged so as to face the flange 78 of the guide 41. That is, the movable flange 95 has one end fixed to the other end of the leaf spring 96 fixed to the guide 41, and is biased toward the flange 78.

The height of the guide wall 40a sandwiched between the flange 76 and the movable flange 91 and the height of the guide wall 41a sandwiched between the flange 78 and the movable flange 95 are the minimum permissible dimension value (about the width dimension of the magnetic tape 1). Set a little smaller than the minimum value of the variation range specified in the standard. As a result, the movable flange 91 is on the edge 1b of the magnetic tape 1, and the movable flange 95 is on the edge 1a of the magnetic tape 1.
The magnetic tape 1 and the flange 7
Press on 6,78. Here, the reaction forces F ₃ and F ₄ generated on the flanges 76 and 78 are the reaction forces against the force of pressing the magnetic tape 1 against the flanges 76 and 78 by the leaf springs 92 and 96 and the couple M generated by the rotation of the rotating body 42. It is possible to more reliably satisfy the precise tape running performance.

At this time, however, it is assumed that the magnetic tape 1 is provided with an appropriate tension T so that buckling does not occur. In the first embodiment described with reference to FIG. 7, the biasing force applied to the magnetic tape 1 from the leaf spring 74 needs to be larger than the couple M generated by the rotation of the rotating body 42. On the other hand, in the present embodiment, by utilizing the couple M acting on the magnetic tape 1, the magnetic tape 1 can be more reliably regulated even if the biasing force of the leaf springs 92 and 96 is set small. Further, the spring constants of both leaf springs 92 and 96 may be the same.

(Fourth Embodiment) Next, with reference to FIGS. 10 and 11, the structure around the rotary recording portion of the magnetic recording / reproducing apparatus in the fourth embodiment of the present invention will be explained. In the second embodiment described with reference to FIG. 8, it can be understood that the magnetic tape 1 is sheared. In the present embodiment, this phenomenon is more positively introduced, and the relationship between the generation of the couple M and the force generated by the flange is applied to more reliably regulate the running of the magnetic tape. Guides 40 and 41 in this embodiment
The configuration is similar to that of the second embodiment. In FIG. 10, 76 and 78 are flanges, 40a and 41a are guide walls formed on the guides 40 and 41, respectively.
The position is substantially symmetrical with respect to the point. The relationship of the x-y-z axes is the same as above.

Now, the distance between the flange 76 and the flange 78 in the z-axis direction is Tw _1, and the width of the magnetic tape 1 running this guide in the x-axis direction is Tw _0. Tw ₀ = Tw ₁ + ΔTw ₁ ( ΔTw ₁ > 0). FIG. 11 shows this from the front for easy understanding. Shear strain γ on magnetic tape 1
Occurs, and its size is the distance between the flanges 76 and 78
_When it is set to _1, it is represented by γ = ΔTw ₁ / L ₁ . At this time, the shearing force F is applied to the flanges 76 and 78.
₅ and F ₆ occur. Although F ₅ and F ₆ is inherently distributed load convenience, also the point at concentrated load was placed in the position of FIG. Due to the mechanical equilibrium, a couple M about the y-axis is generated on the magnetic tape 1. Here, the tension T is given a proper value so that the magnetic tape 1 does not buckle. It is desirable that the shear strain γ be smaller than the elastic limit range.

Generally, the widthwise dimension of the magnetic tape 1 is several 1
It has an error of 0 μm. As an example, the standard of VHS tape is 12.65 ± 0.01 mm. Where VH
Consider a guide as in FIG. 12 using S magnetic tape. At this time, L ₁ = 20 mm, Tw ₁ = 12.63 mm
From the standard, the width of the magnetic tape 1 is Tw _max = 12.66 mm and Tw _min = 12.64 mm. At this time,
The shear strain is γ _max = (Tw _max −Tw ₁ ) / L ₁ γ _min = (Tw _min −Tw ₁ ) / L ₁ and γ _max = 0.1% and γ _min = 0.05%. Generally, in a plastic member, a shear strain of 0.2% or less is within the elastic limit and has almost no effect on the magnetic tape 1. Here, it is understood that the center of the magnetic tape 1 and the axis O point of the rotating body are always coincident with each other, and are not affected by the error in the width dimension of the tape. This means that the use of this guide does not affect the tape width direction error, especially in the arc recording / reproducing method.

(Fifth Embodiment) Next, with reference to FIGS. 12 and 13, the structure around the rotary recording portion of a magnetic recording / reproducing apparatus according to a fifth embodiment of the present invention will be briefly described. In this embodiment,
This is a modification of the fourth embodiment described with reference to FIGS. 10 and 11, and the flanges 76 and 78 perform the same function. The distance between the flange 120 and the flange 76 is set larger than the maximum allowable dimension value of the width of the magnetic tape 1 (the maximum value of the variation range defined by the standard). Similarly, the distance between the flange 122 and the flange 78 is larger than the maximum allowable dimension value of the width of the magnetic tape 1. FIG. 13 is a view of this state viewed from the y-axis direction. Assuming that the maximum width of the magnetic tape 1 is Tw _max and the distance between the flange 76 and the flange 120 in the z-axis direction is Tw ₂ , there is a relationship of Tw ₂ ≧ Tw _max . Here, the distance between the flanges 78 and 122 in the z-axis direction is also equal to Tw ₃ . By adopting the structure shown in FIGS. 12 and 13, it is possible to minimize the deviation of the magnetic tape 1 due to the impact in the z-axis direction. Tw ₂
-Tw _max is preferably in the range of 0 to 50 μm.

As described above, by using the leaf spring, applying the generation of the couple M, and utilizing the shear strain, it is possible to regulate the magnetic tape suitable for the arc recording / reproducing method. .

[0027]

As described above, the arc recording / reproducing method has a drawback that the tracking characteristic is deteriorated due to the influence of the dimension error in the magnetic tape width direction. However, according to the present invention, the dimension error of the magnetic tape width is caused. It is possible to obtain a stable running of the magnetic tape by utilizing the rotation direction of the rotating body with little influence of the above, and at the same time, to obtain a simple and inexpensive magnetic recording / reproducing apparatus without having a complicated tracking control mechanism. You can

[Brief description of the drawings]

FIG. 1 is a perspective view of an arc recording / reproducing apparatus according to Japanese Patent Laid-Open No. 6-139662.

FIG. 2 is a magnetic recording pattern by an arc recording / reproducing method.

FIG. 3 is a perspective view of a main part of a helical scan type VTR.

FIG. 4 is a magnetic recording pattern of a helical scan type VTR.

FIG. 5 is a perspective view of a rotary recording unit of the magnetic recording / reproducing apparatus used in the present invention.

FIG. 6 is a top view of a magnetic recording / reproducing apparatus used in the present invention.

FIG. 7 is a perspective view of the first embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 8 is a perspective view of a second embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 9 is a perspective view of a third embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 10 is a perspective view of a magnetic recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 11 is a front view of the fourth embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 12 is a perspective view of a fifth embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 13 is a front view of a fifth embodiment of the magnetic recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 1 ... Magnetic tape 2, 42 ... Rotating body 3 ... Motor 4, 45a, 45b ... Magnetic head 6, 7 ... Tape guide 38 ... Rotation recording part 40, 41 ... Tape guide 40a, 41a ... Guide wall 68, 72, 76, 78 ... Flange 69, 73, 91, 95 ... Movable flange 70, 74, 92, 96 ... Leaf spring

Claims (6)

[Claims] 1. A magnetic head is attached to a rotating body having a rotation axis in a direction substantially orthogonal to a magnetic tape surface, and the magnetic head is slidably contacted with the magnetic tape to form an arc-shaped recording track for recording and reproduction. In a magnetic recording / reproducing apparatus, a pair of surface guide members that guide the surface of the magnetic tape near both sides of the rotating body, a pair of edge guide members that guide one edge of the magnetic tape, and the magnetic tape. A magnetic recording / reproducing apparatus comprising: a pair of biasing members for biasing the other edge portion. 2. A magnetic head is attached to a rotating body having a rotation axis in a direction substantially perpendicular to the surface of the magnetic tape, and the magnetic head is slidably contacted with the magnetic tape to form an arc-shaped recording track for recording and reproduction. In a magnetic recording / reproducing apparatus, a pair of surface guide members for guiding the surface of the magnetic tape near both sides of the rotating body and the magnetic tape by rotating the rotating body at a position substantially symmetrical to the rotation axis of the rotating body. A magnetic recording / reproducing apparatus comprising a pair of edge guide means for guiding both edges of the magnetic tape against couples generated in the magnetic tape. 3. A magnetic recording system according to claim 2, further comprising a pair of biasing members facing said pair of edge guide means for biasing the edge of said magnetic tape. Playback device. 4. The magnetic recording / reproducing apparatus according to claim 2, wherein the distance between the pair of edge guide means in the width direction of the magnetic tape is set to be smaller than the width of the magnetic tape by a predetermined amount. 5. The gap between the pair of edge guides in the width direction of the magnetic tape is 0.2% due to shear deformation applied to the magnetic tape.
The magnetic recording / reproducing apparatus according to claim 4, wherein the following settings are made. 6. A variation in the edge portion of the magnetic tape is regulated at a position spaced apart from the magnetic tape width by a predetermined distance from each of the pair of edge guide means, facing the pair of edge guide means. 6. The magnetic recording / reproducing apparatus according to claim 4 or 5, further comprising a regulating means for controlling the magnetic recording / reproducing apparatus.