JPH05205361A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To set the inclined angle of a rotary drum to the adequate value, to prevent a magnetic tape from being damaged by reducing the change of a height when the magnetic tape is wound to the rotary drum, and to reduce a running resistance of magnetic tape by making the winding angle to fixed posts small. CONSTITUTION:The guide posts 10, 19 near the rotary drum 5 are arranged perpendicular to the magnetic tape 1, and also inclined guides to change the tape running surface to an inclined surface for helically winding to the rotary drum 5 from the plane whereon tape reels 2, 3 are placed, are provided by fixing one each only to the supply side and take-up side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type magnetic recording / reproducing apparatus such as a VTR.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG. In FIG. 4, a magnetic tape 1 is helically wound around an inclined rotary drum 5 by approximately 180 °, and guide posts 12, 13 for guiding the magnetic tape 1 from the supply-side tape reel 2 to the rotary drum 5 are provided. 14, 8 and the tension pins 27 and the fixed head 24 are arranged perpendicularly to the magnetic tape 1, and the magnetic tape 1 runs on the same running surface as the tape reel. Similarly, guide posts 17, 21, 22, 2 for guiding the magnetic tape 1 from the rotary drum 5 to the take-up side tape reel 3
3, the capstan 31 and the fixed heads 25 and 26 are arranged perpendicularly to the magnetic tape 1, and the magnetic tape 1 runs on the same running surface as the tape reel. In order to helically wind the magnetic tape 1 running on the same plane around the rotary drum 5, the rotary drum 5 is tilted and the guide posts 10 and 19 closest to the rotary drum 5 are attached to the magnetic tape 1. It is a slanted post. The relationship between the rotary drum 5, the magnetic tape 1, and the inclined posts 10 and 19 at this time will be described with reference to FIGS. 5 and 6.

FIG. 5 is a rear view of FIG. 4 seen from the direction a, and FIG.
[Fig. 6] is a side view seen from the direction B. In FIG. 5, the magnetic tape 1 extending from the supply-side tape reel 2 to the inclined post 10
Must be equal to the height B of the magnetic tape 1 from the inclined post 19 to the take-up side tape reel 3. The inclination angle and the inclination direction of the rotary drum 5 and the inclination posts 10 and 19 are set so as to satisfy this condition. Such an arrangement is, for example, the rotary drum 5
The lead angle of wrapping the magnetic tape 1 with respect to
Then, it can be realized by setting the inclination angle θ of the rotary drum 5 to about 10 °. At this time, the displacement δ1 in the height direction of the magnetic tape 1 is about 2.5 mm. In such an arrangement, the height of the magnetic tape 1 does not change except for the peripheral portion of the rotating drum 5, so that the magnetic tape 1 is pulled out from the tape cassette 4 and wound around the rotating drum 5 during the loading operation. It is widely used for a VTR having a wrap angle of the magnetic tape 1 with respect to the rotary drum 5 of about 180 ° because it only needs to be pulled out horizontally and the operation and mechanism structure are simple.

Next, referring to FIGS. 7 and 8, the winding angle of the magnetic tape 1 on the rotary drum 5 is 270 ° to 3 °.
An example in which the same arrangement is applied to the case of 00 ° will be described. In FIG. 7, the height A of the magnetic tape 1 from the supply tape reel 2 to the inclined post 10 and the height B of the magnetic tape 1 from the inclination post 19 to the winding tape reel 3 are shown in FIG. The inclination angle θ2 of the rotary drum 5 that satisfies the condition of being equal to each other is larger than θ1,
It is necessary to incline from 15 ° to 20 °. In this way, the inclination angle of the rotary drum 5 increases and the displacement δ2 in the height direction of the magnetic tape 1 also becomes larger than δ1. Therefore, it is possible to rotate the magnetic tape 1 by simply pulling it out horizontally during the loading operation. The magnetic tape 1 cannot be properly and helically wound around the drum 5. This becomes more remarkable as the winding angle of the magnetic tape 1 with respect to the rotary drum 5 increases. That is, when the wrapping angle of the magnetic tape 1 with respect to the rotary drum 5 is 270 ° to 300 °, it is difficult to realize with the arrangement described here (Japanese Patent Laid-Open No. 58-153261).

[0005]

A magnetic tape is helically attached to a rotary drum arranged at an angle of 270 ° to 300 °.
In the winding method, the tape guide closest to the rotating drum is used as an inclination guide, and when the rotating drum is inclined so that the height of the magnetic tape entering and leaving the rotating drum matches the reference plane defined by the tape cassette, the inclination The angle increases from about 15 ° to 20 °, which is difficult to realize.

When the inclination angle of the rotating drum is set to a value that can be realized, for example, about 10 ° or less, the heights of the magnetic tapes entering and leaving the rotating drum are not equal to each other. An additional pair of tilt guides are needed to correct until they match. Since the tilt guide cannot be a rotating roller, the total winding angle of the magnetic tape with respect to the tilt guide increases, and the frictional load during running of the magnetic tape increases.
Further, although the inclination accuracy of the inclination guide is important for the stable running of the magnetic tape, it is difficult to secure the accuracy because the inclination guide is two pairs, which causes an increase in the production process.

[0007]

In order to solve the above problems, in the magnetic recording / reproducing apparatus of the present invention, a tape cassette having a supply side on which a magnetic tape is wound and a pair of tape reels on the winding side is incorporated. A rotary drum having a magnetic head and inclined with respect to a reference plane formed by the tape cassette,
A pair of first tape pull-out means on the supply side and a wind-up side that rotates around the rotary drum so as to pull out the magnetic tape from the tape cassette and wind the magnetic tape around the rotary drum at a predetermined angle; and the first tape pull-out means. More on the tape reel side, a pair of supply side and take-up side second tape pull-out means for pulling out the magnetic tape, and between the second tape pull-out means and the tape reel,
The magnetic tape is provided between the supply side and take-up side of the third tape pull-out means for pulling out the magnetic tape, and between the second tape pull-out means and the third tape pull-out means in contact with the magnetic tape at an inclination. A magnetic recording / reproducing apparatus provided with a pair of tilt guides on the supply side and the winding side for changing the running surface of the tape from the flat surface on which the tape reel is placed to the flat surface of the tangent portion helically wound around the rotary drum. In the above configuration, there is only one tilt guide that is inclined with respect to the magnetic tape between the supply-side tape reel and the rotating drum, and one between the rotating drum and the winding-side tape reel. is there.

[0008]

According to the present invention, with the above-described structure, the inclined post has two
Since there is only a book, the total winding angle of the magnetic tape with respect to the inclined post is small, and the running load of the magnetic tape can be reduced. Further, since the inclination angle of the rotary drum can be reduced to about the lead angle, the displacement of the magnetic tape running path in the height direction and the inclination angle from the tape cassette surface can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic recording / reproducing apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of a magnetic recording / reproducing apparatus of the present invention, FIG. 2 is a rear view of the drum peripheral portion, and FIG.
Is a side view.

In FIG. 1, 1 is a magnetic tape, 2 is a supply-side tape reel on which the magnetic tape 1 is wound, 3 is a winding-side tape reel on which the magnetic tape 1 is wound, and 4 is a supply-side tape reel 2. A tape cassette having a take-in tape reel 3 built therein, 5 a rotary drum having a head (not shown) for performing magnetic recording and reproduction on the magnetic tape 1, 6 a chassis, 7 a fixed guide post, 8, 9, 12 , 13, 14
Is a guide roller, 10 is an inclined post that inclines and contacts the magnetic tape 1, 11 and 16 are fixed guide posts, 1
7, 18, 21, 22, and 23 are guide rollers, 19 is an inclined post that inclines and contacts the magnetic tape 1, 20 is a fixed guide post, and 24, 25 and 26 are fixed heads, 2
7 is a tension pin for detecting the tension of the magnetic tape 1, 28 is a tension arm on which the tension pin 27 is mounted, 15 is the center of rotation of the tension arm 28, 29 is a spring, 30 is a bracket on the fixed end side of the spring 29, 31 is a capstan, 32 is a pinch roller, 33
Is a pressure applying portion of the pinch roller 32, 34 is a rotation center of the pinch roller pressing applying portion 33, 35 is a solenoid for driving the pinch roller pressure applying portion 33, and 36 is a supply in which the fixed guide post 7 and the guide roller 8 are mounted. Side first tape pull-out means, 37 is a supply-side second tape pull-out means on which the guide roller 9 is mounted, and 38 is a winding-side first tape pull-out means on which the fixed guide post 16 and the guide roller 17 are mounted. 39 is a second tape pull-out means on the take-up side on which the guide roller 18 is mounted, 40 is a stopper for positioning the first tape pull-out means 36 on the supply side, 41
Is a stopper for positioning the second tape pull-out means 37 on the supply side, and 42 is the first tape pull-out means 3 on the winding side.
8 is a stopper for positioning, 43 is a stopper for positioning the winding-side second tape pull-out means 39, and 44 is a supply-side first tape pull-out means 36 and a supply-side second tape pull-out means 37. A guide plate for guiding the loading locus, 45 is a guide plate for guiding the loading locus of the first tape pull-out means 38 on the winding side and the second tape pull-out means 39 on the winding side, and 46 and 47 are guide plates 44, respectively. And a groove provided in the guide plate 45.

Next, the operation will be described. The magnetic tape 1 wound around the supply-side tape reel 2 is pulled out from the tape cassette 4, and the guide roller 14, the tension pin 27, the guide rollers 13 and 12, the fixed head 24,
It is incident on the rotary drum 5 via the fixed post 11, the inclined post 10, the guide rollers 9 and 8, and the fixed post 7, and is wound at a predetermined angle. The magnetic tape 1 separated from the rotating drum 5 has a fixed post 16, guide rollers 17 and 1
8, tilted post 19, fixed post 20, fixed head 25
And 26, the guide roller 21, the capstan 31, and the guide rollers 22 and 23 to be wound up on the winding-side tape reel 3. Here, the guide roller 14, the tension pin 27, the guide rollers 13 and 12, the fixed head 24, the fixed post 11, the guide rollers 9 and 8,
Fixed post 7, fixed post 16, guide rollers 17 and 18, fixed post 20, fixed heads 25 and 26,
Guide roller 21, capstan 31, guide roller 2
2, 23 are arranged perpendicular to the magnetic tape 1.

The tension pin 27 can rotate around the tension arm rotation center 15, and its one end is given a rotation moment by a spring 29 fixed to the bracket 30, so that the tension pin 27 receives the rotation moment from the magnetic tape 1. The tension of the magnetic tape 1 can be measured as an electric signal by providing a rotary encoder (not shown) that is in balance and converts the angular displacement into an electric signal at the position of the rotation center 15.

The operation of the solenoid 35 causes the pinch roller pressing portion 33 to rotate around the rotation center 34, and the pinch roller 32 is pressed against the capstan 31 with the magnetic tape 1 sandwiched therebetween. Where the capstan 31
The magnetic tape 1 can be run at a predetermined speed by rotating the magnetic tape 1 at a predetermined speed.

The guide roller 9 is provided on the second tape pull-out means 37 on the supply side and can move along the groove 46 provided in the guide plate 44. The guide roller 8 and the fixed post 7 are provided on the first tape pull-out means 36 on the supply side, and like the second tape pull-out means 37, can move along the groove 46 provided in the guide plate 44. You can Similarly, on the winding side of the magnetic tape 1, the guide roller 18 is provided on the second tape pulling-out means 39 on the winding side, and can move along the groove 47 provided in the guide plate 45. it can. The guide roller 17 and the fixed post 16 are provided on the first tape pull-out means 38 on the winding side and move along the groove 47 provided in the guide plate 45 similarly to the second tape pull-out means 39. be able to. By moving these tape pull-out means 36, 37, 38, 39 along the grooves 46, 47, the magnetic tape 1 can be pulled out from the tape cassette 4 and wound around the rotary drum 5 by a predetermined angle.

The tilt posts 10 and 19 are mounted on the chassis 6
It is mounted on the top and its position and angle are fixed.

Now, the running surface of the magnetic tape 1 will be described. Now passing through the longitudinal centerline of the magnetic tape 1,
A plane perpendicular to the magnetic tape 1 is defined as a tape running surface.
Further, the tape running surfaces on which the supply-side tape reel 2 and the take-up-side tape reel 3 are placed are referred to as reference planes. Then, the inclined post 10 is fed from the supply-side tape reel 2 via the guide roller 14, the tension pin 27, the guide rollers 13 and 12, the fixed head 24, and the fixed post 11.
The running surface of the magnetic tape 1 does not change and remains the reference plane, and the running direction of the magnetic tape 1 only changes. However, since the inclined post 10 is in contact with the magnetic tape 1 in an inclined manner, the running surface of the magnetic tape 1 changes before and after the inclined post 10. That is, the tape running surface of the magnetic tape 1 from the inclined post 10 through the guide rollers 9 and 8 and the fixed post 7 to the rotary drum 5 is inclined with respect to the reference plane. By selecting this inclined surface so as to include a tangent line on which the magnetic tape 1 is incident on the rotating drum 5, it is possible to contact the rotating drum 5 from the fixed post 7 without twisting the magnetic tape 1.

Similarly, the magnetic tape 1 is replaced by the rotating drum 5.
The fixed post 16 and the guide rollers 17 and 18 are arranged so that the inclined surface including the tangent line that separates from is the tape running surface. The inclined post 19 is in contact with the magnetic tape 1 in an inclined manner, and the running surface of the magnetic tape 1 changes before and after the inclined post 19. Here, the position and inclination of the inclined post 19 are selected so that the running surface of the magnetic tape 1 wound around the inclined post 19 coincides with the reference plane, and the fixed post 20, the fixed heads 25 and 26, the guide roller 21,
If the capstan 31 and the guide rollers 22 and 23 are arranged vertically on the reference plane, they can be arranged on the take-up side tape reel 3
The same surface as the magnetic tape 1 and the tape reel 3 on the winding side
Can be rolled up.

2 and 3, the portion of the running path of the magnetic tape 1 from the supply-side inclined post 10 to the winding-side inclined post 19 via the rotary drum 5 will be described. ..

FIG. 2 is a view of FIG. 1 viewed from the direction a.
FIG. 3 is a view as seen from the direction B. In FIG. 2, the rotary drum 5 is inclined by θ3, but this angle can be set to any angle as long as it is an angle of θ2 or less shown in FIG. 7. That is, in FIG. 3, the magnetic tape 1 that has come out of the tape cassette 4 and is wound around the inclined post 10 is wound around the guide roller 9 while changing its running direction upward, but the distance between the inclined post 10 and the guide roller 9 is increased. For example, when it is relatively close to 10 mm,
The amount of rise is small, and the height of the guide roller 9 is substantially equal to the height of the reference plane of the magnetic tape 1 determined by the tape cassette 4. Here, the guide roller 9 is arranged so as to be inclined so as to wind around the magnetic tape 1 which has already run on the inclined surface after being wound around the inclined post 10. In this embodiment, the magnetic tape 1 wound around the guide roller 9 runs downward. This magnetic tape 1
The traveling direction is changed by the guide roller 8 and the guide post 7 in order to wind around the rotating drum 5, but since the guide roller 8 is arranged in the vicinity of the rotating drum 5, the height of the guide roller 8 is the magnetic tape 1. Is close to the height of the incident point on the rotating drum 5. Therefore, if the distance between the guide roller 9 and the guide roller 8 is increased, the height of the guide roller 8 is decreased, and the inclination angle θ of the rotary drum 5 is increased.
3 becomes smaller. Conversely, if these distances are made smaller, the height of the guide roller 8 becomes higher and the inclination angle θ of the rotary drum 5 becomes larger.
3 becomes larger. These relationships are on the opposite side of the rotary drum 5, that is, on the side of the detachment point of the magnetic tape 1 from the rotary drum 5, on the guide roller 17 and the guide roller 1.
The relationship of 8 holds similarly.

Therefore, the inclination angle of the rotary drum 5 can be set to an appropriate value by the distance between the guide rollers 9 and 8 and the distance between the guide rollers 17 and 18, and the magnetic tape 1 is rotated. Drum 5
The change in height when wrapped around can be reduced. here,
When the magnetic tape 1 is pulled out from the tape cassette 4 and wound around the rotary drum 5, the flanged guide rollers 8, 9, 17, 18 on the pulling means 36, 37, 38, 39 of the magnetic tape 1 are used. The magnetic tape 1 is pulled out while supporting the magnetic tape 1 at the flange portion so as not to shift from the guide roller. Therefore, if the height change of the magnetic tape 1 is large, the end surface of the magnetic tape 1 receives a large force from the flange, and the magnetic tape 1 may be damaged.

Here, the case where the inclination angle of the rotary drum 5 is made to correspond to the lead angle on the rotary drum 5 will be described. This angle is about 4 ° when the width of the magnetic tape 1 is 19 mm and the wrap angle with respect to the rotary drum is about 270 °.
In this case, the amount of change δ3 in the height direction with respect to the reference plane of the magnetic tape 1 is about 6 mm, which is about 60% compared to the example shown in FIG. Further, by tilting the winding lead angle exactly, the lead on the rotary drum 5 becomes horizontal at the point C closest to the tape cassette 4 of the rotary drum 5.
The point C is a point at which the magnetic tape 1 starts to come into contact when the magnetic tape 1 is pulled out from the tape cassette 4 and wound around the rotary drum 5. At this point, the magnetic tape 1 comes into contact with the leads in parallel, so that the magnetic tape 1 leads. It is possible to prevent damage to the magnetic tape 1 that occurs when the magnetic tape 1 runs diagonally on the magnetic tape.

Further, in the prior art shown in FIGS. 5 to 8, the guide post closest to the rotary drum 5 is an inclined post inclined with respect to the magnetic tape 1. In this embodiment, the guide post closest to the rotary drum 5 is located. The guide posts 7 and 16 are perpendicular to the running surface of the magnetic tape 1. Since the magnetic tape 1 wound around the inclined post receives a force that shifts in the width direction when running, the magnetic tape 1 is displaced from its original running position or is deformed by being strongly pressed against the lead portion on the rotary drum 5. Occurs. On the other hand, in this embodiment, since the guide post is perpendicular to the magnetic tape 1, such a force in the width direction of the magnetic tape 1 does not occur. Therefore, the magnetic tape 1 can be stably run.

Further, in the prior art, since the inclined posts 10 and 19 which are the guide posts closest to the rotary drum 5 are mounted on the first magnetic tape pulling-out means 36 and 38, the position and the inclination angle accuracy are improved. Hard to secure. Nevertheless, these tilt posts 10 and 1
Since 9 is located closest to the rotating drum 5, the inclination angle error has a great influence on the running performance of the magnetic tape 1, and a problem arises in that high accuracy is required. According to the present embodiment, since the inclined posts 10 and 19 are mounted on the fixed portion, it is easy to ensure accuracy in position and angle, and
Since it is separated from the rotating drum 5, the influence of the position / angle error on the running performance is small.

Next, the frictional load during running of the magnetic tape 1 will be considered. In order to run the magnetic tape 1 stably with high accuracy, it is necessary to reduce the frictional load during running so that slippage does not occur between the capstan 31 and the magnetic tape 1. In order to reduce the frictional load, it is effective to use guide posts as a rotating roller to reduce the number of fixed posts and to reduce the winding angle of the magnetic tape 1 around the fixed posts. In order to use the guide posts as rotating rollers, it is necessary to contact them at right angles to the magnetic tape 1. In this embodiment, all the guide posts except the inclined posts 10 and 19 can be rotating rollers. is there. The wrap angle of the magnetic tape 1 around the tilt post is related to the size of the tilt angle of the tilt post. The wrap angle may be small if the tilt angle is large, and conversely, if the tilt angle is small, the wrap angle is small. Needs to be increased. Therefore, both the tilt angle and the wrapping angle can be selected so as to have appropriate values. In this embodiment, the tilt angle is 14 ° and the wrapping angle is 30 °. In this way, the total winding angle of the magnetic tape 1 with respect to the fixed post can be reduced, and the running resistance of the magnetic tape 1 can be reduced.

Further, according to the present embodiment, as shown in FIG. 1, since the traveling paths of the magnetic tape 1 on the entrance side and the exit side of the magnetic tape 1 with respect to the rotary drum 5 are made substantially symmetrical, The running characteristics of the magnetic tape 1 at the time of the recording / reproducing operation and at the time of the reverse operation can be made substantially the same. Therefore, there is an effect that the tape running characteristic at the time of special reproduction such as reverse reproduction is improved.

[0027]

According to the present invention, by setting the inclination angle of the rotary drum to an appropriate value, it is possible to reduce the fluctuation of the tape height when winding the magnetic tape around the rotary drum.
It is effective in reducing the stress generated in the magnetic tape and preventing damage to the magnetic tape. In particular, when the inclination angle of the rotary drum is set to correspond to the winding lead angle on the rotary drum, the magnetic tape contacts the lead in parallel, so that the magnetic tape can be prevented from being damaged when the magnetic tape obliquely contacts the lead.

Since the guide post in the vicinity of the rotary drum can be arranged at a right angle to the running surface of the magnetic tape, there is no generation of a force to shift in the width direction due to the running of the magnetic tape, and the inclined post is mounted on the fixed portion. Therefore, it is easy to ensure accuracy in both position and angle, and the magnetic tape can be stably run.

Since all the guide posts except the pair of inclined posts can be used as the rotating rollers, the total winding angle of the magnetic tape with respect to the fixed posts can be reduced,
The running resistance of the magnetic tape can be reduced and the running characteristics can be improved.

Since the running paths of the magnetic tape on the entrance side and the exit side of the magnetic tape with respect to the rotary drum can be made substantially symmetrical, the running of the magnetic tape during normal recording / reproducing operation and during reverse operation. The characteristics can be made almost the same.

[Brief description of drawings]

FIG. 1 is a plan view of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a rear view of the magnetic recording / reproducing apparatus according to the present invention.

FIG. 3 is a side view of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 4 is a plan view of a conventional magnetic recording / reproducing apparatus.

FIG. 5 is a rear view of the rotating drum portion when wound around 180 °.

FIG. 6 is a side view of the rotating drum portion when wound around 180 °.

FIG. 7 is a rear view of the rotating drum portion when wound around 270 °.

FIG. 8 is a side view of the rotating drum portion when wound around 270 °.

[Explanation of symbols]

1 ... Magnetic tape, 2 and 3 ... Tape reel, 5 ... Rotating drum, 10, 19 ... Inclined post, 7, 8, 9, 11,
12, 13, 14, 16, 17, 18, 20, 21, 21,
2, 23 ... Guide roller, 31 ... Capstan, 32 ...
Pinch roller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokuhisa Yanagihara 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture Inside the Ritsuryo Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A tape cassette containing a pair of tape reels on which a magnetic tape is wound and a winding side, and a rotary drum which has a magnetic head and is inclined with respect to a reference plane formed by the tape cassette. A pair of first tape pull-out means on the supply side and on the winding side for pulling out the magnetic tape from the tape cassette and winding the magnetic tape around the rotary drum at a predetermined angle, and the first tape pull-out means. On the tape reel side of the means,
A pair of second tape pulling-out means for feeding the magnetic tape and a winding side, and the second tape pulling-out means and the tape reel are in contact with the magnetic tape in a slanted manner. It is characterized in that each of the supply side and the winding side is provided with an inclination guide for changing a traveling surface from an installation surface of the tape reel to an inclination surface for helically winding the rotary drum. Magnetic recording / reproducing device. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the tilt guide is fixed at a predetermined position and angle. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the winding angle of the magnetic tape with respect to the rotary drum is between 270 ° and 300 °. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein an inclination angle of the rotary drum is equal to a winding lead angle at which the magnetic tape is helically wound around the rotary drum. 5. The traveling path of the magnetic tape from the supply-side tape reel to the rotating drum, and the traveling path of the magnetic tape from the rotating drum to the tape reel on the winding side according to claim 1. Is a magnetic recording and reproducing device that is substantially symmetrical.