JPH03278356A - Tape feed control system and tape guide for recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent step winding from occurring by detecting tape feed height in the neighborhood of a reel, and varying relative height difference between the tape feed height and the setting height of the reel. CONSTITUTION:Detecting means 71, 72 which detect the tape feed height in the neighborhood of the reel, and a control means which controls the change quantity of a varying means 81 to vary the relative height difference between the tape feed height and the setting height of the reels 40, 41 are provided. The control means sends driving signals to correct the change quantity of the tape feed height to the varying means 81, for example, of laminate ceramic, etc., corresponding to a signal from the detecting means. In such a way, it is possible to keep the tape feed height in the neighborhood of a supply side reel constant, and to prevent the influence of the step winding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording/reproducing device using a tape. This article relates to a model number of "step winding" and a tape running control method Vc suitable for preventing its occurrence.

[Conventional technology]

In a so-called tape recorder, tape is wound around two reels. And, for example, 8 mi IJ V
For TR cassette tapes, the reel is provided with 91 pairs of seven lunges corresponding to both edges of the tape. In addition, compact cassettes and D
In the AT, instead of having the seven lunges described above, two sheets are installed in the cassette with the tape sandwiched in the width direction of the cassette.

These flanges and sheets are provided to prevent the tape from coming off the reel when being wound onto the reel, or from shifting in the width direction, resulting in so-called "step winding." If the distance between the pair of 7 lunges and the two sheets matches the width of the tape, the step winding will not occur at all, but on the other hand, the tape edge may slide against the 7 lunge or This causes problems such as fluctuations in the running speed of the tape and damage to the tape edges. Therefore, although the distance between the pair of 7-lunges and the two 7-toes was set close to that of the 7-toe, it was necessary to set it slightly larger.

According to the standard of f'J v TR, for tape @aO-, the reel 7 lunge interval is &5~a9■
is set.

[Al to be Solved by the Invention] As a result, 1c. In the above-mentioned prior art, it was inevitable that step winding would occur by the amount of the above-mentioned relatively large interval.

However, if there is a step winding on the reel on which the tape is wound, the next time the tape is unwound from this reel, the running height of the tape will be equal to the height of the step in the step winding. There has been a problem in that track trace performance during recording and reproduction due to fluctuations is degraded.

In addition, the tape edge begins to strongly slide on the 7 flange portion of the tape guide installed near the reel, and furthermore, the tape causes out-of-plane deformation, so-called buckling, near the sliding contact portion with the flange portion. There was a misunderstanding that tape loss may occur.

The purpose of the present invention is to eliminate the drawbacks of the prior art described above,
It is an object of the present invention to provide a tape running control method that prevents the influence of multi-stage winding and the occurrence of multi-stage winding.

[Means to solve bladder problems]

In order to achieve the above object, the present invention provides the following (a) to
The method (d) was adopted.

(a) a detection means for detecting a tape running height in the vicinity; an ffr changing means for changing a relative height difference between the tape running height near the reel and a set height of the reel; and information from the detection means. and control means for controlling the amount of change in the relative height difference in the variable means.

(b) The detection means is installed in the tape guide section or built into the tape guide.

(c) An elevating mechanism for the reel stand is provided as the R variable means.

(d) Change the setting angle of the tape guide as the variable means! ! 11″ 4f throw (do.

[Effect]

The following (1) to (4) are added to each of the means (a) to (d) above.
).

(1) The operation of the means (a) will be described. First, we will explain the effect of preventing the effect of multi-stage winding.The effect of 9 is obtained on the reel on the tape supply side.In other words, the tape running height in the vicinity of the reel on the supply side is constantly determined by the detection means. A signal corresponding to the tape running height is input to the control means to increase N%. now,
When the supply reel approaches a stage winding section that is deviated from the reference tape winding height, the tape running height changes and the signal from the detection means also changes. The control means corresponds to this amount of change and sends one excitation signal to the variable means for correcting the change in the tape running height. As a result, the tape running height near the supply reel is kept constant at the base value, and the influence of step winding can be prevented.

Kyu/C% step winding! To explain the amount of cloth to be prevented, two effects are obtained at the reel on the tape winding side. Nine signals corresponding to the tape running height are input to the control means. Now, if the running height of the tape entering the winding-side sensing means deviates from the basic height, the signal from the sensing means also changes in accordance with the amount of deviation.

The control means responds to this amount of change and sends a drive signal to the variable means for correcting the change in tape running height. The winding height line base value of the tape at the 7th lunge of the 1st take-up reel is kept constant, and the occurrence of step winding can be prevented.

(2) With the means (b), the tape edge height can be detected in a state where the tape is not deformed in the width direction such as curling, so that a high detection n degree can be obtained.

(3) Since the height on the reel side can be changed by means (c), the difference in height between the tape running height and the set height of the reel can be measured by hand.

(4) Said means; d) /C can be placed in the tape guide section of 18 FJ to cause the tape to rise and fall, and the tape running height can be changed, so that the tape running height and the reel can be changed. The height difference between the set height and the set height can be changed.

[Actual example]

An actual MfA model in which the present invention is applied to a video tape recorder ("/TR) will be explained below with reference to FIGS. 1 to S.

First, an overview of the entire recording/reproducing apparatus of the present invention will be explained.

FIG. 1 is a plan view showing one example 71 of a tape loading mechanism for a VTR according to the present invention, in which 1.2 is a guide roller as a width regulating guide, 3 and 4 are guide rollers, and 5.
7 ring, 6 magnetic tape, 7.8 inclined guide, 9
．． 10 is an impedance roller, 11 is an iAC (voice/control) head, 12 is a pinch roller, 13 is a cab stun, 14 is a tension bin, 15, 161': m
Guide plate, 17~ZJc brown'? 3 grooves, 2 (22 is the loading link, 23-26ζ catch, 27 is the loading motor, 28 is the cab stan motor, 29-32
Guide base, 33d tension lever, 34ζ pinch roller arm, 35q bin, 36ζ worm wheel% 37 is pinch roller drive motor, 38 is tape cassette% 39μ scooping section, 401': Supply reel 41
is the take-up reel, 42 is the supply reel stand, 45 is the take-up reel stand, 44 is the shear %, 45 is the tension play)
, 46i pin.

In FIG. 1, a cylinder 5 is provided on the chassis 44 so as to be inclined at a predetermined angle.
A guide plate 15 is provided on one side, and a guide plate 16 is provided on the other side. These guide plates 16, 17 are mounted with one end thereof and partially located in the opening 39 of the nine-tape cassette 38, and are arranged so as to go around the cylinder 5 from this position. The other end is slightly wider than the end on the tape cassette 38 side. This other end of the guide plate 17 is the side where the magnetic tape is inserted into the cylinder 5'/c.
The cylinder 5f:) is on the upstream side, and the above other a of the guide plate 16 is
Similarly, the i section is the side where the magnetic tape 6 is away from the seventh cylinder 5, that is, the upstream side of the seventh cylinder 5.

Two guides 17 and 18 are placed on the guide plate 15 and extend from the end of the tape cassette 38 on the opening 39 side to the upstream end of the cylinder 5, with the guide #18 extending from the guide groove 17. is also arranged on the cylinder 5 side, and -4 is located near the cylinder 5. The upstream ends 1c of the cylinders 5 in the guide grooves 17.18 each have a catcher 23.2.
5 is provided. Guide base 29 equipped with guide rollers 1 each serving as a guide roller 5% width regulation guide
#1117 and #18 are movably attached to the guide plate 15 along guide grooves 17 and 18 respectively.
are located within the opening 39 of the tape cassette 38 at one end and the catcher 25.25K" at the other end, respectively.
Therefore, the position is determined.

Also, apply one tape to the guide plate 16 in the same way.
- Two guide grooves 19 and 20 extending from the 2M1 part on the opening side of the cylinder 5 to the lower i side end of the cylinder 5 are thrown into the 1
The bar guide groove 19 is disposed closer to the cylinder 5 than the guide groove 20 and is placed upright near the cylinder 5 at one end thereof. Catchers 26 and 24 are provided at the downstream end of the cylinder 5 in the guide $1920, respectively. Guide rollers each serve as a width regulating guide 2. Guide rollers 4 are mounted on the guide bases 31 and 32, which are attached to the guide plate 16 so as to be movable along guide grooves 19 and 20, respectively. Opening 3? a catcher 26 at the other end;
．． 24.

In Figure @1, guide bases 29, 30. ! 1 (32 shows the state at the Iil!lii end of the guide $17.18 and $19.20, respectively.

FIG. 2 is a perspective view showing these guide plates 15, 16 and parts related thereto, where 47 is a tape lead, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the same figure, the plan of the guide plate 15 is parallel to the sea-744 (1st ≦)' IC in the part where the guide #17 is provided, but ζ is above the cylinder 5 in the part where the guide #18 is provided. 15 on the side, a sloped portion 15a that slopes upward with respect to the chassis 744 from a portion parallel to the chassis 44 to the upstream side.
is provided. Therefore, the guide groove 17 extends 1,000 degrees to the chassis 44, but the guide groove 18 extends parallel to the chassis 44 from the tape cassette 38 (FIG. 1) side end, and rises at the inclined part 15a from the middle. Superior R, lateral distraction.

Regarding the guide plate 16, the part where the guide groove 20 is provided is parallel to the chassis 44, but the part where the guide groove 19 is provided is located downstream of the cylinder 5 from the part parallel to the chassis 44 to this downstream side. A nine inclined portion 16a is provided at the bottom of the chassis 44 to be inclined downwardly with respect to the chassis 44. therefore,
The guide groove 20 has an extension knife parallel to the chassis 44, and the guide groove 1
9 extends parallel to the chassis 44 from the end on the tape cassette 58 side, descending from the middle at an inclination gA16a and extending below the cylinder 5.7).

Since the guides s17 to 20 are formed in this way, when the guide bases 29 to 32 are moved from the tape cutter nose 38 side, the guide grooves 17 and 17 are formed in the guide bases 29 and 32, respectively.
20 in parallel to the chassis 44, and then descends;
fg and jlK are determined by catchers 25 and 26 near cylinder 5, respectively.

FIG. 2 shows a state in which guide bases 29, 30, 3 (32) are positioned by catchers 23, 25, 26, 24, respectively;
．． □ so that it is located between the guide rollers 3 and 1 on the top of the
An inclined guide 7° impedance roller 9 is provided on the guide plate 15 from the guide roller 5 side, and is positioned between the guide rollers 2 and 4 on the guide base 5 (32).
Impedance roller 10 from the guide roller 2 side. A.C.
A head 11 and an inclined guide 8 are provided on a guide plate 16.

Returning to FIG. 1, on the chassis 45 there are two loading rings 2 (2
2 is placed. These loading rings 2 j
+ 22 two upper and lower/C arranged r-1 here, C guide plate 1
It's ¥4 below 5.16. These are connected to the coding motor 27 mounted on the upper z/Ca of the coding ring 2 (22q shear 744) via a gear section, and are rotated in opposite directions by the loading motor 27, and guided by the rotation of the loading ring 210. As the base 29°60 rotates, the guide bases 3j and 32 move respectively.Here, the rotation angle fi10 of the loading ring 21 with respect to the center of rotation is
8 degrees, and the rotation angle of the loading ring 220 is 120 degrees. For this reason, the rotational speed of the loading ring 2 (22) is different.A small magnet is provided on the lower surface of the loading ring 22, and a sensor such as a Hall element is provided on the shear 44. When the sensor detects the small magnet, the loading ring 2 (22 stop timings are obtained.

On the side of the supply reel 40 of the tape cassette 38, a tension lever 35 is engaged, centered around a bin 46 on a tension plate 45.
The tip m<the tension bin 14 is installed.

Further, a worm wheel 36 is provided on the take-up reel 41 side of the tape cassette 38 and is rotatably driven by a pinch roller drive motor 37.
A pinch roller arm 34 is provided on the pin 35 on the shaft to which the pin 6 is mounted. This pinch roller arm 34
A Kfl via f roller 12 is provided at the tip of the Kfl via f roller 12, and the pinch roller arm 54 is rotated clockwise around the bin 35 by the pinch roller drive motor 57. It can come into contact with the rotating capstan 15.

Next, the operation of this embodiment will be explained.

Tape cassette now! It is assumed that the +8 is still attached and is in an unloading state. At this time, the supply side reel stand 42 rotatably provided on the yarn 44
When the supply reel 40 of the tape cassette 38 is
- The winding reel 41 is mounted on the loop 543, and the magnetic team 1
5, the tape is stretched between a supply reel 40 and a take-up/knoll 41 within a tape curved 38. Mano, Ni no Tosa, guide base 29°3o, 3 (32! im t guide rollers 3, 1, 2°4, tension bin on the tension lever 33, pinch roller 12 of the pinch roller arm 34, etc.) , is located further back than the magnetic tape 6 in the opening 39 of the tape cassette 38.

When the loading operation starts offshore in such a state, the loading motor 27 rotates the loadin f IJ song 1 clockwise, the guide bases 29 and 30 move along the guide grooves 17 and 18, and the loading ring 22
rotates counterclockwise, and the guide base 3 (32) rotates along the guide grooves 19, 20.

In addition, as the loading ring 22 rotates counterclockwise, the tension lever 33 rotates counterclockwise with play with respect to the loading ring 22, and the pinch roller drive motor 37 rotates to rotate the pinch roller arm. 34 rotates like a clock.

Due to the movement of the guide bases 29, 30, 31, 32 (the force of the guide rollers 3, 1, 2.4 mounted on these), the magnetic tape 6 in the tape cassette 68 is hooked and pulled out from the tape cassette 3B. At this time, the magnetic tape 6 is brought into contact with the magnetic tape 6 being pulled out by the T/7-J bin 14 and the pinch roller 12, but these do not contribute to pulling out the magnetic tape 6 from the tape cassette 38.

Thereafter, the guide bases 29, 30, 3 (32) are carried to the catchers 23, 25, 26, and 24 and positioned.

The magnetic tape 6 is wrapped around the outer periphery of the cylinder 5 in a predetermined corner recess and is wound along the spiral tape lead portion 47 to complete the loading operation.

FIG. 5 is a plan view showing the tape running path in the loading state obtained in this way, in which 48°49 is a tensile guide roller, 50 is a full-width erasing head, and 5 (52r
j guide roller, and parts corresponding to those in FIG. 1 are given the same reference numerals.

3. After applying the magnetic tape 6ζ, the supply Lee, ν40 to the tension roller 48, the tension roller 48, the tension roller 49, and the tension roller 49, the entire head is removed. 50, and the traveling direction is changed to 10,000 of the cylinder 5 by the guide roller 3.

The magnetic tape 6 whose direction has been changed has its surface aligned with the spider guide 7.
It is tilted according to the inclination of the cylinder 5, and after contacting the impedance roller 9, it is brought into contact with the cylinder 5 by the guide roller 1, which is a guide.

9. On the downstream side of the cylinder 5, the magnetic tape 6 from the cylinder 5 contacts the guide roller 2, which is a width regulating guide, contacts the impedance roller 10 and the AC head 11, and then the tape surface is sheared by the inclined guide 8. 744 (Figure 1)
The guide roller 4 changes the tape running direction toward the tape cassette 58. Direction changed
After contacting the guide roller 51, the tape 6 passes between the pinch roller 12 and the capstan 13, and further contacts the guide roller 52 to take up the tape cassette 31) and the take-up reel 41/c. It will be done.

When the above-mentioned tape running path collapses and the magnetic tape moves between the pinch roller 12 and the capstan 33a, and the middle thread member 13 is rotated by the carbstan motor 2, the magnetic tape 6 runs along this running path. . This place,
The tape tension is detected by the tension bin 1, and a load is applied to the supply reel 40K in response to the detection, so that the tape tension l/ is kept constant.

Next, the tape running control method according to the present invention will be explained in detail.

In this embodiment, the detection means includes tape guides (hereinafter referred to as sensor guides) 7 (72) each having seven sensors installed near the reel 441, and the variable means includes tape widths of the reels 40 and 41. The elevating mechanism and control means in the direction are the control #direct path described later.

First, the detection means will be described. In Figure 3, 7(
Reference numeral 72 is a sensor guide, and the tape 6 is held at a small angle so as not to cause tape running load.

As shown in FIG. 4, there is a reflective photo-inser 71p on the side facing the upper end of the tape. The spot is located in the corner of the tape winding, and is fixedly supported at a height that covers approximately half of the sensor 71p when the tape is at the basic tape running height. The photosensor 71p shown in FIG. 5, Internal structure 1 of the iC sensor guide, is placed inside the exterior body and is protected and dust-proof. Of the exterior body, the sliding part 719 with the tape 6 is made of a transparent material (glass, plastic, etc.).
Light can pass through it. Now, photo sensor 71
The light emitted from P passes through the transparent material 719 and hits the tape 6, and then enters the cell as shown in Figure y84.
Tape portion 6p facing 71p (diagonal line N in Figure 4)
) is reflected only by the light corresponding to the transparent material 7.
19 and is received by the sensor 71p, and a signal output corresponding to this light receiving leaf is obtained. With this, the reel J, l, which is a variable means of the shift 6, such as ji, step winding, etc.
JM) Side section of the lifting mechanism ■Full figure shown, No. 69, 4
7 palms on 4, 80ζ reel motor, 42.43 is the reel stand.

40.41 is a reel, 6 ka: tape. The reels 40 and 41 on which the tape 6 is completely wound are placed on reel stands 42 and 43 at a height of 7C. Reel stand 42.43
is connected to the reel motor 80 via the motor 7to 5ob2. Further, the reel motor 80 has seven flange portions 80ai at the bottom in the figure. A cylindrical laminated ceramic 8 is located between this 7 flange portion 8G& and 7 palm 44.
1 is connected to C. Laminated ceramic is a material that expands and contracts in the stacking direction depending on the applied voltage value.In the case of this embodiment, the stacking direction is taken in the vertical direction in FIG. 6.9. The reels 40 and 41 can be expanded and contracted in the vertical direction depending on the applied voltage value, that is, the reels 40 and 41 can be moved up and down.

Next, the external use of this embodiment as a whole and the control means will be described.

First, the operation on the tape supply side will be explained.

The No. 1 output from the sensor 71P also changes according to the amount of change in height at which the running phase changes. Here, in the actual M, the phase between the tape running high weir and the signal output is determined in advance.
By monitoring the signal output,
It is possible to constantly detect the change f in the tape running height.

Here, since this detection means detects the height of the tape edge using the shape of the tape wrapped around the tape guide, it is possible to prevent the tape from causing out-of-plane deformation in the tape width direction such as curling. It is possible to detect the tape edge height-gt with high accuracy.

Further, although the present detection means detects the height of the upper end of the tape, it may also be a method of detecting the height of the lower end of the tape.

For Takura, if you install Sen f on both the top and bottom ends of the tape,
The width of the tape can also be detected at the same time9, for example, the height t of the center of the tape width can be determined by taking into account variations in the width of the tape.
It also becomes possible to perform highly accurate detection.

Next, the first variable means of this embodiment will be described.

In FIG. 3'/c'J6, when the tape is rotated in the normal direction, the ζ reel 40 is on the tape supply side, and the reel 41 is on the tape winding side, and when the tape is reversed, the two are reversed. Now consider the supply side during normal rotation, that is, reel 40@gold.

The running height of the tape 6 fed out from the reel 40 is constantly detected by a sensor guide 71 near the reel 40. The seventh factor (a) shows a block diagram of the operation on the tape supply side in this embodiment. A reference signal corresponding to the reference tape running height is input, and a signal from the sensor guide 71, which is a detection means, is input. The output is compared with the output, and if there is an error due to step winding or the like, the error signal is inputted to the control means, and an equal drive voltage is applied to the reel lifting mechanism which is the variable means. As a result, even if the tape running height changes due to step winding, etc., the height of the reel 40 is displaced in the direction to correct the tape running height gt reference value, and the subsequent tape running height is detected again. and provide feedback to the comparison department.
By using one or more functions, which is a so-called closed loop servo, the tape running height in the vicinity of the tape supply reel can be maintained constant, and the influence of one stage winding can be prevented.

In addition, this supply side j') This month's c1 tape is reversed.

The reel 411IIC operates in the same manner and provides similar effects.

Next, the operation on the tape winding side will be explained.

In the fifth case, the reel 41 becomes the take-up side at 7C when the tape rotates normally. The running height of the tape entering the reel 41 is constantly detected by a sensor guide 72 near the reel 41. FIG. 7(b) shows a block diagram of the operation in the tape winding INK of K actual examples. A reference signal in charge of the base tape running height is input, and the signal is detected from the sensor guide 72 which is a detection means. If there is an error due to the change in tape running height, the error signal t f! I
ll to the N means, and apply an equal drive voltage to the reel lifting mechanism, which is the variable means. And reel 4
The height of 1 is determined by the action of 5 or more, which is a so-called open loop servo that moves up and down so that the tape winding height between the flanges of the reel 41 remains constant even if the tape running height changes. , Tape winding side knoll/(;o
'Tape winding height 1-constant/C': This will prevent the occurrence of double winding. f: Oh, this winding side f)
Is it the same 7ic on the ζ reel 40 side when the tape is reversed?
'! : You can get the same effect by using it.

In this embodiment, we will briefly describe the second variable means.
The sensor guide 7 (72) has a configuration in which the inclination angle of the sensor guide 7 (72) is different from 5r.
is fixedly supported on a support base 85 which is located in front of the slit flsa5at. A laminated ceramic 86 is inserted into the open end of the slit portion 85a. The laminated ceramic is stacked vertically in the figure, and similarly expands and contracts in the vertical direction depending on the applied voltage. For this, support stand 8
As a result, the inclination angle of the sensor guide 7 (72) becomes variable in the directions of arrows 87 and 88 in Figure (a).
When the tape 2 is tilted in the direction of the arrow 87, the tape 6 receives an upward force and the tape running height can be corrected in the vertical direction. Also, in the 1st amendment at this time, the Ikkyūki tomb threat 1 Ubatsuku seal - 1 Den-ō and Rin are in charge of the evening. Also, when the senna guide 7 (72) is tilted in the direction of the arrow 88, the tape 6 receives the downward movement and corrects the tape running height downward. Although there is a concern that the height of the photosensor 71p will change due to this, the angle at which the sensor guide 7 (72) is tilted is minute and the height positional deviation of the photosensor 71p can be ignored.

The above-mentioned second variable means operates in the same manner as the first variable means on the tape supply side reel, so that the tape running height is kept constant and the influence of step winding can be prevented.

In addition, on the winding side, the reel height in the first variable means remains unchanged, but the tape running height is changed by the second variable means, resulting in poor control and, as a result, the winding height on the reel is changed. It is held constant and the step winding is prevented from collapsing.

Although the second variable means changes the inclination angle of the sensor guide itself, the same effect can be obtained by using Type 7 in which the sensor guide and another tape guide ζ are brought into contact and tilted.

Finally, regarding the entire A row, this practical example takes into consideration tape running in both forward and reverse directions, but since this is a device that runs only in one direction, the influence of step winding or the occurrence of tape winding may occur in either direction. If the device requires only one reel to be prevented from collapsing, it is only necessary to take measures against one reel.

〔Effect of the invention〕

According to the present invention, it is possible to control the tape running height itself and the winding height on the reel in accordance with fluctuations in the tape running height, so it is possible to prevent the influence of step winding and its occurrence.

Furthermore, it is possible to detect the height of the engine with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a recording/reproducing apparatus ft in one embodiment of the present invention, FIG. 2 is a perspective view showing its tape path, and FIG.
The figure is a plan view of the tape bus, Figure 4 is a front view showing the sensor guide, Figure 5 is a sectional view showing the structure of the sensor guide, Figure 6 is a sectional view showing the reel lifting mechanism, and Figure 7 is the servo system. FIG. 8 is a side view and a front view showing the second variable means. 6...Tape 40.41...Reel 7 (72...Sensor guide 42.43...Reel stand 81...Laminated ceramic.

Claims (1)

[Claims] 1. Recording information on a tape (6), or recording information on a tape (6)
A head (80) that reproduces more information, and a tape (6) stretched between two reels (40, 41).
) and a tape guide means for forming a running path of the tape (6) so as to be recordable and playable by the head (80), the tape running height in the vicinity of the reel being detected. a detecting means for changing the relative height difference between the tape running height near the reel and a set height of the reel; and a variable means for changing the relative height difference in the variable means based on information from the detecting means. A second tape running control method for a recording/reproducing apparatus characterized by comprising a control means for controlling the amount of change, wherein the detection means is installed in a tape guide section or built in the tape guide. 3. The tape running control method for a recording and reproducing apparatus according to claim 1, wherein the variable means is a reel stand elevating mechanism. 4. The tape running control system for a recording/reproducing apparatus according to claim 1, wherein the variable means changes the set angle of the tape guide. 5. A tape guide characterized by having a built-in or attached sensor for detecting tape edge height.