JP3009947U - Magnetic tape cassette - Google Patents

Abstract

(57) [Abstract] [Purpose] In a magnetic tape cassette, to prevent disorder of the winding of the tape and to make the inclination angle of the outer peripheral surface of the hub with respect to the rotation axis of the tape reel as small as possible. [Constitution] Outer peripheral surface 12a of the hub 12 around which the tape 20 is wound
Is formed such that its central axis C ′ is inclined with respect to the rotation axis C of the tape reel 10 by an extremely slight angle θ (0.05 ≦ θ ≦ 0.5 degrees). When the tape 20 is wound around the outer peripheral surface 12a of the hub 12, the lower edge 20a of the tape 20 comes into contact with the inner surface 11a of the lower flange 11, and the tape 20 follows the surface shape of the inner surface 11a so that the tape 20 is disturbed. Will not occur.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic tape cassette, and more particularly to an improvement of a flanged tape reel included in this magnetic tape cassette.

[0002]

[Prior art]

 Conventionally, a tape reel provided in a magnetic tape cassette such as a video tape cassette has a hub around which a magnetic tape is wound around the outer peripheral surface as it rotates, and two flanges fixed to both end surfaces of the hub. In general, the outer peripheral surface of the hub is formed into a cylindrical surface centering on the rotation axis of the tape reel.

The two flanges are substantially parallel to each other and are formed substantially perpendicular to the rotation axis of the tape reel. Further, the inner surfaces of the two flanges facing each other are formed in a substantially flat shape, or have a slight inclination (about 0.4 degree) so that the inner surface interval becomes wider from the inner peripheral portion toward the outer peripheral portion. It is known that it has been formed.

By the way, since the distance between both flanges of the tape reel is set to be slightly larger than the tape width, a slight change in the tape position when the tape is wound causes the tape to move between the flanges. It was unavoidable that the winding position of the wrap around the rotating shaft varied and the winding disorder occurred.

The tape reel in which the winding disorder has occurred not only impairs the aesthetic appearance, but when the tape is unwound as it is, the position in the width direction (rotational axis direction) of the tape fluctuates, and the reading head of the playback device and the tape are The relative position of the tape fluctuates to cause a reading error of information recorded on the tape, a decrease in S / N, or the like, or the edge of the tape may be bent.

Further, if the tape cassette is stored for a long time in a state where the winding is disturbed, the tape is stretched (distorted) due to the winding tightening phenomenon, and the tape may be wound around the device at the time of use or the recorded information may not be recorded. It may cause various failures such as loss.

Therefore, various devices have been devised to prevent the winding disorder. For example, in the tape cassette disclosed in Japanese Utility Model Laid-Open No. Sho 58-18 7083, the outer peripheral surface of the hub is inclined at a certain angle with respect to the rotation axis. And the inner surface of the flange is formed so as to be substantially perpendicular to the outer peripheral surface of the hub, and the tape wound around the outer peripheral surface of the hub is wound around the inclined outer peripheral surface of the hub in a substantially right angle direction. Since the tape is attached to the inner surface of the tape, the edge of the tape contacts the inner surface of the flange on the intersection of the plane including the center axis and the rotation axis of the hub outer surface with the inner surface of the flange. From the edge to the outer edge, the tape follows the shape of the inner surface of the flange, and its edges are arranged neatly without any irregularity or step.

According to the description of Japanese Utility Model Laid-Open No. 58-187083, if the inclination angle of the outer peripheral surface of the hub is not within the range of 0.5 to 10 degrees, the effect of preventing winding disorder can be obtained. It is said that they cannot do it.

[0009]

[Problems to be solved by the device]

 However, in the tape reel of the tape cassette disclosed by the above utility model registration application, since the tape is wound in a direction substantially perpendicular to the outer peripheral surface of the hub and the winding diameter becomes large, rotation of the central axis of the outer peripheral surface of the hub occurs. As the angle of inclination with respect to the axis increases, the height of the tape in the rotation axis direction of the tape reel near the outermost circumference of the wound tape (rolled ball) increases, and the tape increases from the inner circumference to the outer circumference. The occupying height (width) of the tape over the part increases.

When the occupied width of the tape becomes large, it is necessary to widen the flange interval of the tape reel, and the width of the magnetic tape cassette as a whole becomes large, which is not preferable in practice. Further, if the outer peripheral surface of the hub is largely tilted with respect to the center axis of rotation, the moment of rotation becomes non-uniform during one rotation period, so it is desirable to make this tilt angle as small as possible.

The present invention has been made in view of the above circumstances, and has a magnetic tape provided with a tape reel that prevents the tape from being disturbed while keeping the inclination angle of the outer peripheral surface of the hub small with respect to the rotation axis of the tape reel. It is intended to provide a tape cassette.

[0012]

[Means for Solving the Problems]

 In the magnetic tape cassette of the present invention, by tilting the center axis of the outer peripheral surface of the hub of the tape reel slightly to the rotation axis of the entire tape reel, each time the tape is wound around the hub once, A force is generated that causes the tape edge to contact the flange on the slanted side of the hub, and this force positively contacts the tape edge with the inner flange surface, so that the tape edge generally follows the inner flange surface. It was designed to be arranged in order.

That is, the magnetic tape cassette of the present invention is a tape reel including a hub around which a magnetic tape is wound around an outer peripheral surface as it rotates, and two flanges fixed to both end surfaces of the hub. The hub outer peripheral surface is equipped with a tape reel that is formed into a cylindrical surface centered on an axis inclined at an angle within the range of 0.05 degrees to 0.5 degrees with respect to its rotation axis. It is what

Here, when the magnetic tape is wound around the outer peripheral surface of the hub, the inner surface of either one of the two flanges is formed into a substantially fan-shaped region of 1 degree or more and 60 degrees or less around the rotation axis. The inclination angle of the central axis with respect to the rotation axis can be set so as to come into contact with the edge of the magnetic tape.

In addition, the substantially fan-shaped region is more than 0 degrees around the rotation axis from a line of intersection of the plane including the rotation axis and the central axis and the inner surface of the flange on the side where the hub is inclined. It may be formed by the surface of a radially extending projection formed in an area on the inner surface of the flange within a range of degrees. In this case, it is desirable that the protrusions are formed to have a height of 50 μm or more and 300 μm or less based on the average height of the inner surface of the flange on which the protrusions are formed. It is desirable that the angle around the axis of rotation in the height region is formed to be more than 0 degree and within 60 degrees.

The substantially fan-shaped contact area is not formed by the surface of the protrusion as described above, but is formed as a relative protrusion by forming a concave shape around the contact area. It may be one.

That is, the above-mentioned substantially fan-shaped region is more than 0 degrees around the rotation axis from the intersection line on the side where the hub is inclined among the intersection lines of the plane including the rotation axis and the central axis and the inner surface of the flange. It may be a region of 60 degrees or less on the inner surface of the flange and formed (remaining) between two recesses formed on the inner surface of the flange and spaced from each other.

The recess may be formed so that the depth thereof becomes shallower as the distance around the rotation axis from the substantially fan-shaped region increases, or the recess becomes closer to the hub. It may be formed to have a shallow depth.

Further, in the magnetic tape cassette according to the present invention, it is more preferable that the inclination angle of the central axis of the outer peripheral surface of the hub with respect to the rotation axis is within the range of 0.05 degrees to 0.15 degrees.

The magnetic tape cassette of the present invention is not limited to the one in which the hub is inclined, but may have a configuration in which the flange is inclined. That is, by tapering the flange of the tape reel so that its axis substantially perpendicular to the inner surface is slightly inclined with respect to the rotation axis of the entire tape reel, the inner surface of the flange is inclined relative to the hub, and the tape Each time it is wound one turn, the force that causes the edge of the tape to contact the flange is generated, and this force positively contacts the edge of the tape with the inner surface of the flange, so that the edge of the tape as a whole contacts the inner surface of the flange. It may be arranged along the lines.

For example, from a hub that winds a magnetic tape around its outer peripheral surface as it rotates, and two flanges that are fixedly mounted on both end surfaces of the hub and that have inner surfaces facing each other that are substantially planar. And a tape reel in which the inner surfaces of the two flanges are formed such that the axis perpendicular to the inner surface is inclined at an angle within the range of 0.05 degrees to 0.5 degrees with respect to the rotation axis. It may be configured.

The inclination angle at this time is more preferably set to an angle within the range of 0.05 degrees or more and 0.15 degrees or less, as in the magnetic tape cassette according to the present invention.

Further, the hub and the flange, which are the constituent elements of the tape reel provided in the magnetic tape cassette of the present invention, may be made of resin, or may be a light metal such as duralumin. The shape of the flange is not limited to the generally used disk shape, and other shapes may be adopted.

[0024]

[Effect of action and device]

 According to the magnetic tape cassette of the present invention, the rotation of the tape reel causes the tape to be wound around the outer peripheral surface of the hub having a central axis inclined with respect to the rotation axis, and the outer peripheral surface is inclined to prevent the tape from being wound. At this time, the edge of the tape contacts the lower flange. Therefore, the edge of the tape is supported along the inner surface of this flange.

Therefore, according to the surface shape of the inner surface of the flange formed in a flat shape, the upper edge of the tape does not have a step, and the tape is neatly aligned without winding disorder.

The same effect can be obtained in a tape reel whose flange is inclined with respect to the rotation axis.

In the magnetic tape cassette of the present invention, the outer peripheral surface of the hub is inclined with respect to the rotation axis at an angle of 0.05 degrees or more and 0.5 degrees or less, preferably 0.05 degrees or more and 0.15 degrees or less. Therefore, even if the diameter of the tape wound around the outer peripheral surface of the hub is large, the tape occupying width (height) in the tape reel rotation axis direction can be small. There is no need to widen the space.

As described above, according to the magnetic tape cassette of the present invention, the winding angle of the tape can be prevented while reducing the inclination angle of the outer peripheral surface of the hub or the inner surface of the flange with respect to the rotation axis of the tape reel. it can.

[0029]

【Example】

 A magnetic tape cassette according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a magnetic tape cassette according to a first embodiment of the present invention, and FIG. 2A is a plan view showing a tape reel 10 provided in the magnetic tape cassette 1 shown in FIG. 2B is a sectional view showing a cross section taken along line II of the tape reel 10 shown in FIG. 3A, and FIG. 3 is the same as FIG. 2B for explaining the operation of the tape reel 10 shown in FIG. It is a sectional view.

The magnetic tape cassette 1 of this embodiment is for a video, and two tape reels 10 are rotatably provided in the tape cassette body, and each tape reel 10 has a long tape reel. One of the two ends of the magnetic tape 20 is fixed and wound with rotation.

As shown in FIG. 2B, the tape reel 10 has a resin hub 12 around which the magnetic tape 20 is wound around the outer peripheral surface 12 a by rotating around the rotation axis C, and the hub 12. A lower flange 11 made of resin, which is formed in a disk shape on the lower end surface of the rotary shaft C about the rotation axis C and is integrally formed with the hub 12, and is substantially parallel to the lower flange 11. And an upper flange 16 made of a resin plate and fixed to the upper end surface of the hub 12, and the outer peripheral surface 12a of the hub 12 is formed into a cylindrical surface centered on the central axis C '. There is. The central axis C ′ is formed so as to be inclined with respect to the rotation axis C by an extremely small angle θ (0.05 ≦ θ ≦ 0.5 degrees), and the intersection O between the rotation axis C and the extension surface of the lower surface of the lower flange 11 is O. And the intersection O'of the central axis C'and the extension surface of the lower surface of the lower flange 11 coincides with each other. Therefore, the outer peripheral surface 12 a of the hub 12 is not perpendicular to the inner surfaces of the lower flange 11 and the upper flange 16.

The symbol K in the figure indicates the direction of inclination of the central axis C ′ with respect to the rotation axis C.

The tape 20 whose one end is fixed to the hub 12 of the tape reel 10 configured as described above has a direction perpendicular to the rotation axis C when the tape reel 10 is driven to rotate about the rotation axis C. In the direction of the arrow Y, and is successively wound around the outer peripheral surface 12a of the hub 12. In the winding process, the hub peripheral surface on the side inclined to the inner surface 11a side of the lower flange 11 (right side from the rotation axis C in FIG. 3; referred to as region I for ease of explanation) When the tape 20 is wound around the tape 12a, a component of the tension acting on the tape 20 along the hub peripheral surface 12a of the region I produces a force acting on the tape 20 in the arrow Z direction.

Therefore, the illustrated lower edge 20a of the tape 20 wound in the region I contacts the inner surface 11a of the lower flange 11, and the tape 20 is supported along the surface shape of the inner surface 11a of the flange 11. As a result, the tape 20 is wound in an orderly manner along the inner surface 11a of the lower flange 11 without causing winding irregularity, and the step of the upper edge 20b is not generated.

On the other hand, when the tape 20 is wound around the hub peripheral surface 12a on the side inclined to the side of the inner surface 11a of the lower flange 11 (left side from the rotation axis C in FIG. 3; referred to as area II). In view of the relationship with the tape 20 wound around the hub peripheral surface 12a in the region I, the tape 20 is stacked in an orderly manner perpendicularly to the hub peripheral surface 12a without any step.

As described above, according to the magnetic tape cassette of this embodiment, the lower edge of the tape wound around the tape reel is positively brought into contact with the inner surface of the lower flange, so that the tape is disturbed. It is possible to prevent the edge of the tape from being broken, the tape from being partially stretched due to tightening of the winding during storage of the tape, or the vertical movement when the tape is running.

If the inclination angle θ of the hub peripheral surface 12a is smaller than 0.05 degrees, the tape 20 will be affected by the lower edge of the tape 20 due to the positional fluctuation during the feeding of the tape 20 and the runout of the inner surface of the lower flange 11. The divergence angle α (see FIG. 1) of the substantially fan-shaped contact area with the inner surface 11a of the lower flange 11 is out of the range of the angle required to obtain the desired effect of preventing winding disorder, and the desired effect is obtained. I can't.

Here, the desired winding disorder prevention effect means that the winding disorder amount S is the same as the lower edge of the tape in the graph showing the relationship between the spread angle of the tape edge contact area and the winding disorder amount in FIG. The maximum winding turbulence amount S'max (= the maximum winding turbulence amount S ₀ when the tape winding disorder amount S ₀ is used as a reference in the state of point contact with the inner surface of the lower flange (ideal state where the spread angle of the contact area is as close to 0 degrees as possible) shall mean that the Smax -S ₀₎ within _{50% (S 0 ≦ S ≦} S'max / 2), practical problem as long as uneven winding within this range rather than, the condition The satisfying spread angle of the contact area is within the range of more than 0 degree and less than 60 degree from FIG.

Therefore, the tilt angle θ needs to be set to 0.05 degrees or more in order to suppress the winding disorder amount within a desired range.

When the inclination angle θ of the hub peripheral surface 12a is larger than 0.5 degrees, the occupied width h of the tape 20 on the area II side becomes large. This increases as the winding diameter of the tape 20 around the rotation axis C increases. As a result, it is necessary to widen the gap between the upper and lower flanges so that the upper edge 20b of the outer peripheral edge of the wound tape 20 on the region II side does not contact the upper flange 16. However, if this space is infinitely extended, it becomes impossible to accommodate the tape reel 10 in the magnetic tape cassette body, or the tape reel 10 interferes with the inside of the magnetic tape cassette body and cannot freely rotate. There is a risk.

Therefore, the inventor of the present application does not change the distance between the flanges 11 and 16 so that the occupied width h of the tape 20 on the area II side falls within the range of the distance between the flanges 11 and 16 in the conventional tape reel. The inclination angle θ was determined experimentally. As a result, it was found that if the inclination angle θ exceeds 0.5 degrees, it is necessary to widen the space between the upper and lower flanges, which is not preferable in practice. Further, considering the running variation of the tape 20, it is more preferable to set it to 0.15 degrees or less.

As described above, the magnetic tape cassette according to the present embodiment has the magnetic tape cassette 20 under the magnetic tape 20 wound around the outer peripheral surface 12a of the hub 12 within a range in which the flange spacing of the tape reel is practically no problem. By positively contacting the side edge 20a with the inner surface 11a of the lower flange 11 at an occupying angle of 60 degrees or less in the abutting range, it is possible to prevent winding disorder of the magnetic tape.

In the tape reel 10 of the above-described embodiment, as shown in FIG. 4, concave portions 11a ₂ and 11a are formed on both outer side adjacent portions in the rotation direction from the desired spread angle of the contact area of the inner surface 11a of the lower flange 11. By forming ₃ , the spread angle α of the contact region 11a ₁ can be easily set to a desired angle of 60 degrees or less.

The recesses 11a ₂ and 11a ₃ are not limited to those having a rectangular cross section as shown in FIG. 4, and are shown, for example, in FIG. 5 from the viewpoint of easiness of manufacturing and securing of strength. As shown, it may be formed in a shape such that its depth becomes shallower as the circumferential distance around the rotation axis C increases from the contact area 11a ₁ , or as shown in FIG. It may be formed in a shape such that its depth becomes shallower as it gets closer to the hub 12.

The inner surface 11a of the lower flange 11 has a contact area 11a with the lower edge 20a of the tape 20. ₁ As shown in FIG. 7, among the lines of intersection between the virtual plane including the rotation axis C and the central axis C ′ and the inner surface 11a of the lower flange 11, the intersection line portion L ( Hereinafter, it is not always necessary to include the intersection line L), and it may be formed within the range of the angle γ within ± 60 degrees around the rotation axis C with the intersection line L as a reference. For convenience of explanation, ± 60 degrees means that the rotation direction of the tape reel 10 is set to (+) and the opposite direction is set to (-), and within a range of 120 degrees about the intersection line L. It is meant.

The angles β ₁ and β ₂ around the rotation axis C where the recesses 11a ₂ and 11a ₃ are formed are both within 90 degrees.

Further, the contact region between the inner surface 11a of the lower flange 11 and the lower edge 20a of the tape 20 is formed as a region which is relatively projected with respect to the recess by forming the recess in the periphery as described above. However, the inner surface 11a of the lower flange 11 may be formed by providing a protrusion protruding or protruding toward the upper flange 16. In this case, the protrusion, that is, the portion higher than the average height of the inner surface 11a of the lower flange 11 is an angle within ± 60 degrees around the rotation axis C with reference to the intersection line L as shown in FIG. It is necessary to be formed within the range of γ. Further, it is necessary to set the angle around the rotation axis C (the angle corresponding to the angle α in FIG. 7) in the area that is 1/2 or more of the maximum height of the protrusion within 60 degrees.

At this time, it is preferable that the height of the protrusion is a value within the range of 50 μm or more and 300 μm or less based on the average height of the inner surface 11 a of the lower flange 11.

FIG. 9 is a sectional view similar to FIG. 3, showing a tape reel capable of obtaining the same effect as the magnetic tape cassette in which the outer peripheral surface of the hub is inclined. This tape reel 10 'has a resin hub 12' around which the magnetic tape 20 is wound around the outer peripheral surface 12a 'by rotating around the rotation axis C1 and a rotation axis C1 on the lower end surface of the hub 12'. On the other hand, a lower flange 11 'made of a disc-shaped resin which is perpendicular to the axis C2 inclined by an angle θ'and centered on the axis C2 and a hub 12 which is substantially parallel to the lower flange 11'. And an upper flange 16 'made of a disc-shaped resin fixed to the upper end surface of the ′, and the inclination angle θ ′ is set in the range of 0.05 degrees to 0.5 degrees.

The tape 20 whose one end is fixed to the hub 12 'of the tape reel 10' having the above-described structure is rotated with respect to the rotation axis C1 by rotating the tape reel 10 'around the rotation axis C1. In the vertical direction of the arrow Y ', and is successively wound around the outer peripheral surface 12a' of the hub 12 '. During this winding process, the hub peripheral surface on the side inclined to the inner surface 11a 'of the lower flange 11' so as to approach the outer peripheral surface 12a 'of the hub 12' (right side of the rotation axis C1 in FIG. 9). When the tape 20 is wound around the tape 12a ', the tape 20 is moved in the Z direction by the component of the tension acting on the tape 20 along the hub peripheral surface 12a'.

Therefore, the illustrated lower edge 20a of the wound tape 20 contacts the inner surface 11a 'of the lower flange 11', and as a result, the tape 20 does not cause winding disturbance and the inner surface 11a of the lower flange 11 '. It is wound in order along the line ', and no step is formed on the upper edge 20b.

On the other hand, the tape 20 is attached to the hub peripheral surface 12a 'on the side inclined to the inner surface 11a' of the lower flange 11 'away from the outer peripheral surface 12a' of the hub 12 '(left side from the rotation axis C in FIG. 3). As the tape 20 is wound, the tape 20 is layered in an orderly manner without forming a step vertically on the hub peripheral surface 12a '.

In the magnetic tape cassette of each of the above-described embodiments, the inner surface of the flange of the tape reel is formed in a substantially flat shape as shown in FIG. 10 (A) to simplify the description of the operation. However, as shown in FIG. 10 (B), the inner surface interval becomes wider as it goes from the inner peripheral portion to the outer peripheral portion. It may be formed with a gradient within a degree).

Hereinafter, specific experimental examples of the present invention will be described.

(Experimental Example 1) A tape is wound around the magnetic tape cassette of the present invention and the conventional magnetic tape cassette, and the relative height of the upper edge in the region I shown in FIG. 3 is measured from the inner circumference of the tape winding ball. FIG. 11 shows the result of measurement over the outer peripheral portion. FIG. 11A shows the case of the magnetic tape cassette according to the present invention, and FIG. 11B shows the case of the conventional magnetic tape cassette.

The experimental conditions are as follows.

(1) Equipment used-Magnetic tape cassette; D2 format compliant 3/4 inch width metal tape-VTR used; Sony D2 format compliant DVR-2 (2) Condition-VTR 20x speed FF / REW tape Winding ・ The magnetic tape cassette of the present invention has an inclination angle of 0.1 degree with respect to the center of rotation of the central axis of the outer peripheral surface of the hub 12, and a widening angle of 30 degrees in the contact area with the lower flange of the tape as shown in FIG. It was also confirmed that the magnetic tape cassette of the present invention reduces the amount of winding disorder to 2/3 to 1/2 compared to the conventional one.

(Experimental Example 2) A part of the inner surface of the lower flange of the magnetic tape cassette in which the inclination angle of the hub is set to 0.1 degree (divergence angle p degree) extends from the inner peripheral portion to the outer peripheral portion. The contact area with the tape of the protrusion of 100 μm was formed, and the sum of the winding surface fluctuation amounts when the angle p was changed was measured.

FIG. 12A is a schematic view of a tape reel having this protrusion, and the protrusion is provided so that its center line in the width direction and the maximum inclination direction K of the hub coincide with each other. .

As shown in FIG. 12 (B), the sum of the winding surface fluctuation amounts means that when the height difference between the adjacent tapes exceeds 20 μm in the measurement of the height of the upper edge. , Is the value obtained by adding the difference in height. Therefore, when the difference in height between adjacent tapes is less than 20 μm, the difference in height is not added. Therefore, the larger the variation in edge height, the larger the sum of the winding surface variation.

(1) Equipment used: VTR used: Sony D2 format compliant DVR-2. Magnetic tape cassette used: (reel) cassette size M (tape) D2 format compliant 3/4 inch width metal tape (2) Conditions: VTR 20x speed FF / REW is used to wind the tape, and the winding surface of the supply side reel of the tape cassette is measured. ・ Inclination angle of the hub; 0.1 degree The tape is wound with respect to the spread angle of the contact area with the tape measured in Experimental Example 2 above. Figure 13 shows the measurement results of the sum of the surface fluctuations.

As can be seen from FIG. 13, it was confirmed that as the spread angle of the contact area with the tape increases, the sum of the winding surface fluctuation amounts increases, and the winding disorder increases.

(Experimental Example 3) A part (width 10 mm) in the circumferential direction of the inner surface of the lower flange of the magnetic tape cassette whose hub inclination angle is set to 0.08 degrees has a height of 200 μm from the inner peripheral portion to the outer peripheral portion. A contact area with the tape was formed on the protrusion of, and the amount of roll surface deflection when the position (angle γ around the rotation center axis with respect to the maximum inclination direction K of the hub) was changed was measured.

FIG. 14 is a schematic view of a tape reel having this protrusion.

The above-mentioned amount of roll surface deviation means the entire tilt angle (amount of surface deviation) from the inner peripheral portion to the outer peripheral portion of the wound ball of the tape wound on the tape reel. .

(1) Equipment used-VTR used; Sony D2 format compliant DVR-2-Magnetic tape cassette used (reel) cassette size M (tape) D2 format compliant 3/4 inch width metal tape (2) Conditions- VTR 20x speed FF / REW is used to wind the tape, and the tape winding side of the supply side reel of the tape cassette is measured by an optical displacement sensor. ・ Hub tilt angle: 0.08 degrees ・ Position with protrusions: -180 degrees to +180 degrees 30 degree interval Note that when the maximum tilt direction K of the hub and the center line of the protrusion in the width direction are aligned with each other as a reference (0 degree), the case where the protrusion is located on the left side of the maximum tilt direction K is correct. (+), When it is located to the right and when it is negative (-).

FIG. 15 shows the measurement results of the rolling surface deviation, that is, the inclination angle of the winding ball, with respect to the position of the protrusion measured in Experimental Example 3, that is, the position where the contact region with the tape is formed.

As can be seen from FIG. 15, when the position of the protrusion coincides with the maximum inclination direction K of the hub, the rolling surface deviation is minimized, and the protrusion distance is set to be away from the maximum inclination direction K of the hub. As a result, it was confirmed that the amount of roll surface deflection increased.

The rolling surface deviation of 0 μm corresponds to an inclination angle of 0 degrees, the surface deviation amount of 100 μm corresponds to an inclination angle of 0.05 degrees, and the surface deviation amount of 200 μm corresponds to an inclination angle of 0.10 degrees.

Experimental Example 4 As shown in FIG. 16, the inclination angle of the hub with respect to the rotation axis was changed while keeping the lower flange perpendicular to the rotation axis. In this case, in the range where the angle of inclination of the hub is small (about 5 degrees or less), due to the play between the shaft hole of the hub and the drive shaft of the drive unit, the tape reel as a whole will not tilt even if the hub is tilted. Therefore, it is possible to obtain the same state as in FIG. 3 in which only the outer peripheral surface of the hub is inclined.

FIG. 17 is a graph showing the sum of the tape winding surface variation with respect to the inclination angle of the outer peripheral surface of the hub.

As can be seen from FIG. 17, it was confirmed that when the inclination angle of the outer peripheral surface of the hub exceeds 0.04 degrees, the sum of the tape winding surface variation amounts sharply decreases.

Experimental Example 5 As shown in FIG. 18, the lower flange was inclined with respect to the entire tape reel, and the inclination angle of this lower flange was changed. In this case, since the entire tape reel does not tilt with respect to the rotation axis, it is possible to obtain the same state as in FIG. 9 in which only the lower flange is tilted.

FIG. 19 is a graph showing the sum of the tape winding surface variation with respect to the inclination angle of the lower flange.

As can be understood from FIG. 19, when the inclination angle of the lower flange exceeds 0.06 degrees, it was confirmed that the value of the sum of the amount of tape surface variation of the tape sharply decreases.

[Brief description of drawings]

FIG. 1 is an exploded plan view showing a magnetic tape cassette according to a first embodiment of the present invention.

2A is a plan view showing a tape reel 10 provided in the magnetic tape cassette 1 shown in FIG. 1, and FIG. 2B is a sectional view showing a cross section taken along line II of the tape reel 10 shown in FIG.

FIG. 3 is a sectional view for explaining the operation of the tape reel 10 shown in FIG.

FIG. 4 is a schematic perspective view showing a part of a tape reel in which a contact area is formed by two concave portions having a rectangular cross section.

FIG. 5 is a schematic perspective view showing a part of a tape reel showing an example in which the shape of a recess is different.

FIG. 6 is a schematic perspective view showing a part of a tape reel showing an example in which the shape of a recess is different.

FIG. 7 is a plan view of a tape reel showing a range of a contact area 11a ₁ with a tape edge.

FIG. 8 is a graph showing the relationship between the spread angle of the contact area and the winding disorder amount.

FIG. 9 is a sectional view showing an example of a tape reel having the same effect as the magnetic tape cassette of the present invention.

FIG. 10 is a front view showing the state of the inner surface of the flange of the tape reel in the magnetic tape cassette of each embodiment of the present invention.

FIG. 11 is a graph showing the results of measuring the relative height of the upper edge, where (A) is the magnetic tape cassette according to the present invention,
(B) shows a conventional magnetic tape cassette

FIG. 12A is a schematic diagram of a tape reel having a protrusion, and FIG. 12B is a diagram illustrating the sum of winding surface fluctuation amounts.

FIG. 13 is a graph showing the measurement result of the sum of winding surface fluctuation amounts

FIG. 14 is a schematic view of a tape reel having a protrusion.

FIG. 15 is a graph showing the measurement results of the rolling surface deviation of the roll surface with respect to the position of the protrusion.

FIG. 16 is a schematic view showing a state where the hub is inclined with respect to the entire tape reel.

FIG. 17 is a graph showing the measurement result of the sum of the tape winding surface variation with respect to the hub inclination.

FIG. 18 is a schematic view showing a state in which the lower flange is inclined with respect to the entire tape reel.

FIG. 19 is a graph showing the measurement result of the sum of the amount of tape surface variation with respect to the inclination of the lower flange.

[Explanation of symbols]

 10 Tape reel 11 Lower flange 11a Inner surface of lower flange 12 Hub 12a Outer surface of hub 20 Tape 20a Lower edge of tape

Claims (9)

[Scope of utility model registration request] 1. A tape reel comprising a hub around which a magnetic tape is wound around an outer peripheral surface as it rotates, and two flanges fixed to both end surfaces of the hub, wherein the outer peripheral surface of the hub is , 0.05 degree or more with respect to the axis of rotation 0.5
A magnetic tape cassette comprising a tape reel formed in a cylindrical surface having an axis inclined at an angle within a range of less than or equal to a central axis. 2. When the magnetic tape is wound around the outer peripheral surface of the hub, the inner surface of one of the two flanges is rotated once or more around the rotating shaft.
2. The magnetic tape cassette according to claim 1, wherein the magnetic tape cassette is in contact with the edge of the magnetic tape over a substantially fan-shaped area within 60 degrees. 3. The rotation of the substantially fan-shaped region from a line of intersection of the plane including the rotation axis and the central axis and an inner surface of the flange on the side where the hub is inclined, around the rotation axis. 3. The magnetic tape cassette according to claim 2, wherein the magnetic tape cassette is formed by a surface of a radially extending projection formed in an area on the inner surface of the flange within 60 degrees. 4. The magnetic tape according to claim 3, wherein the protrusion is formed to have a height of 50 μm or more and 300 μm or less based on the average height of the inner surface of the flange on which the protrusion is formed. cassette. 5. The protrusion has a height of 1 / max of the maximum height of the protrusion.
4. The magnetic tape cassette according to claim 3, wherein an angle about the rotation axis in a region having two or more heights is formed within 60 degrees. 6. The rotation of the rotation axis from a line of intersection of the plane that includes the rotation axis and the central axis and an inner surface of the flange on the side where the hub is inclined, the line having a substantially fan-shaped shape. 3. A magnetic field according to claim 2, which is an area on the inner surface of the flange within 60 degrees, and is a portion formed between two recesses formed on the inner surface of the flange and spaced apart from each other. Tape cassette. 7. The recess is formed so that its depth becomes shallower as the distance around the rotation axis from the substantially fan-shaped region increases. The magnetic tape cassette described. 8. The magnetic tape cassette according to claim 6, wherein the recess is formed so that the depth thereof becomes shallower as the hub approaches the hub. 9. A tape reel comprising a hub around which a magnetic tape is wound around an outer peripheral surface as it rotates, and two flanges fixed to both end surfaces of the hub, wherein the outer peripheral surface of the hub is , 0.05 degree or more with respect to the axis of rotation 0.15
A magnetic tape cassette comprising a tape reel formed in a cylindrical surface having an axis inclined at an angle within a range of less than or equal to a central axis.