JPH10241328A - Tape cassette device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tape cassette device reducing the possibility to scratch the surface of a magnetic tape by making two procedures compatible such as to fine the surface roughness of a guide roller and to reduce the slip with the magnetic tape. SOLUTION: By forming the surface roughness of a cylindrical surface of the guide roller 21 to be about 0.8μm, the surface roughness is made drastically finer as compared with the conventional practice hard to be lower than about 2μm. Thus, the possibility to scratch the surface of the magnetic tape 65 is remarkably reduce. Also, by forming an annular recessed part 21a on the cylindrical surface of the guide roller 21, the air of an air film F is escaped from this annular recessed part 21a even though the air film F is coming to generate between the guide roller 21 and the magnetic tape 65. The slip with the magnetic tape 65 is thereby reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, a VTR (V
The present invention relates to a tape cassette device which is used in a recording / reproducing apparatus for recording images and sounds such as an image tape recorder and stores the recording tape on which the images and sounds are recorded in a rotatable manner. And a guide roller that rotates.

[0002]

2. Description of the Related Art As a conventional tape cassette device, there is, for example, a tape cassette device 50 as shown in FIG.
In the figure, reference numeral 51 denotes an upper half case portion which forms substantially the upper half of the case portion of the tape cassette device 50 and has a large opening in the mating portion 51a. Symbol 53 is
The lower half case portion, which forms substantially the lower half of the case portion of the tape cassette device 50 and has a large opening in the mating portion 53a.

In FIG. 1, reference numeral 57 denotes a cylindrical reel hub, and 59 denotes a lower half case portion 5 of the reel hub 57.
A lower reel plate 61 integrally formed at the end on the third side, and 61 is an upper reel plate assembled to the end on the upper half case portion 51 side of the reel hub 57. The reel hub 57 and the lower reel plate 59 form a lower reel 64.
4 and the upper reel plate 61 form a tape reel 63 as a whole. Then, two such tape reels 63 are housed side by side in the tape cassette device 50.

A magnetic tape (recording tape) 65 is wound between the two tape reels 63, and the magnetic tape 65 is rotatable during recording and reproduction.
In the same figure, reference numeral 67 denotes a tape guide, 69 denotes a guide pin, 71 denotes a guide roller, 73 denotes a reel lock, and 76 denotes a lid lock.

FIG. 7 is a plan view of the lower half case portion 53 as viewed from the mating portion 53a. A part thereof is formed concentrically outside the reel base insertion hole 55 formed on the bottom 80 of the lower half case portion 53 along a virtual cylindrical surface 82 having a diameter larger than that of the lower reel plate 59 of the reel 63. Do
An inner wall 84 of the reel insertion portion is provided upright.

The lower half case 53 has a guide roller pedestal 74 on which the lower end of the guide roller 71 is mounted and supported, and a lower end of a guide pin 69 formed at the center of the guide roller pedestal 74. A guide pin mounting hole 72 is formed integrally.

Reference numeral 75 denotes a tape guide holding hole for pressing the lower end of the tape guide 67, and 77 denotes a reel lock 7.
3 is a reel lock mounting pin for mounting the same. The lower half case portion 53 is formed by integral molding using ABS resin.

FIG. 8 is a plan view of the upper half case portion 51. The upper half case portion 51 includes a guide roller 7.
1, a guide roller seat 86 opposed to the upper end, and a guide pin mounting hole 88 formed at the center of the guide roller seat 86 to which the upper end of the guide pin 69 is mounted.
Are integrally formed.

Reference numeral 90 denotes a tape guide pressing pin for pressing the lower end of the tape guide 67, and reference numeral 92 denotes a reel lock mounting hole for mounting a reel lock 73. Such an upper half case portion 51 is also formed by integral molding using ABS resin.

Referring to FIGS. 7 and 8, the lower half case 5
3 and the upper half case portion 51 are each provided with four screw holes B. The screw portion B of the lower half case portion 53 and the matching portion 51a of the upper half case portion 51 are joined together. By inserting and screwing a total of four screws into the hole B, the entire case portion of the tape cassette device 50 is formed.

FIG. 9 is a view showing a guide roller 71. The peripheral surface of the guide roller 71 is formed as a simple cylindrical surface. As shown in FIG. 10, the guide roller 71 is a magnetic tape 65 pulled out from the tape reel 63.
, And rotates while guiding the running direction of the magnetic tape 65. The upper end of the magnetic tape 65 in the drawing is drawn out (or drawn in) in the direction of the arrow in FIG.

[0012]

The above guide roller 7
1 indicates that the theoretically, the larger the surface roughness of the peripheral surface and the larger the contact angle (embrace angle) with the magnetic tape 65, the larger the frictional resistance and the higher the followability to the magnetic tape 65. Become. However, when the running speed of the magnetic tape 65 is low, this is the case. However, when the running speed is high (high speed), that is, when the rotation speed of the tape reel 63 increases, as shown in FIG. A thin film of air (air film F) enters between the roller 71 and the magnetic tape 65, and a phenomenon that hinders contact between the guide roller 71 and the magnetic tape 65 occurs.

For this reason, the air film F causes the magnetic tape 65 to float up from the peripheral surface of the guide roller 71, so that the frictional resistance is reduced and the ability to follow the magnetic tape 65 is reduced. The number is smaller. For this reason, the speed difference between the magnetic tape 65 and the magnetic tape 65 increases, and when slippage occurs, the magnetic powder applied to the magnetic tape 65 drops off, deteriorating the recording / reproducing performance of the magnetic tape 65. .

In order to prevent slippage between the guide roller 71 and the magnetic tape 65, it is conceivable to increase the surface roughness of the guide roller 71. 65, the guide roller 71 and the magnetic tape 65
It is conceivable to reduce the slip between

However, if the surface roughness of the guide roller 71 is increased for the purpose of reducing the slip in this way, the slip does not become completely zero.
There is a problem that the degree of damage to the surface of No. 5 is promoted more than before.

From such a background, conventionally, the guide roller 71 has a surface roughness of at least about 2 μm, but in this case, the phenomenon of the air film occurs and the number of rotations of the guide roller is reduced. The speed difference with the magnetic tape 65 increases. So still
The problem that the performance at the time of recording / reproduction of the magnetic tape 65 is deteriorated due to the slip is not solved.

In view of the above problems, the present invention can reduce the surface roughness of the guide roller and reduce the slip between the guide roller and the surface of the magnetic tape, thereby making it possible to damage the surface of the magnetic tape. It is an object of the present invention to provide a tape cassette device with reduced performance.

[0018]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a case where a tape drive comprises a case section comprising an upper half case section and a lower half case section, and two tape reels housed side by side in the case section. A recording tape wound around the tape, and a guide roller rotatably provided between the upper and lower half case portions and having a cylindrical surface that rotates in contact with the running recording tape. In the cassette device, the surface roughness of the cylindrical surface of the guide roller is around Rz = 0.8 μm, and an annular concave portion is formed in the cylindrical surface of the guide roller.

According to the tape cassette device having such a configuration, the surface roughness of the cylindrical surface of the guide roller is set to Rz = 0.
By setting the thickness to around 8 μm, the surface roughness is greatly reduced as compared with the conventional case where it is difficult to reduce the thickness to around 2 μm, and thereby the possibility of damaging the surface of the magnetic tape can be significantly reduced. .

Further, by forming an annular concave portion on the cylindrical surface of the guide roller, even if an air film is generated between the guide roller and the magnetic tape, air can escape from the annular concave portion. For this reason, preventing the magnetic tape from floating from the cylindrical surface of the guide roller, increasing the adhesion between them and increasing the frictional resistance,
The followability of the guide roller to the magnetic tape can be enhanced to reduce slip.

As described above, even if the surface roughness of the cylindrical surface of the guide roller is set to around Rz = 0.8 μm, slip between the guide roller and the magnetic tape can be reduced, so that the surface of the magnetic tape may be damaged. Can be significantly reduced.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be specifically described below with reference to the attached drawings. 1 to 4 are views showing a first embodiment of a tape cassette device according to the present invention. The description of the same components as those of the conventional tape cassette device will be omitted, and the same components as those of the conventional tape cassette device will be described using the same reference numerals, and only the embodiments relating to the characteristic portions of the present invention will be mainly described.

FIG. 1 is a view showing the guide roller 21. The surface roughness of the outer peripheral surface (cylindrical surface) of the guide roller 21 other than a concave portion 21a described later is Rz = 0.
The roughness is around 8 μm, that is, Rz = 0.8 ± 0.2 μm = 0.6 to 1.0 μm.

Although the outer peripheral surface of the guide roller 21 is basically formed in a cylindrical surface, it is not a simple cylindrical surface like the conventional guide roller 71. That is, an annular concave portion 21a is formed at the longitudinal center of the cylindrical surface of the guide roller 21, and annular concave portions 21a are also formed at both ends of the cylindrical surface.

The recess 21a is formed by machining, and has a width W of 1 to 2 mm and a depth d of 40 to 50 μm. In this manner, by setting the width W and the depth d of the concave portion 21a, the side edge of the width W of the concave portion 21a does not become an annular edge, and the surface of the magnetic tape 65 is brought into contact with the concave portion 21a. Damage can be prevented. Further, a shaft hole 21 b through which the guide pin 69 is inserted is formed in an axis portion of the guide roller 21.

As described above, by setting the surface roughness of the cylindrical surface of the guide roller 21 near Rz = 0.8 μm,
The surface roughness is greatly reduced as compared to the case where it was conventionally difficult to reduce the thickness to around 2.0 μm, and thus the possibility of damaging the surface of the magnetic tape 65 can be significantly reduced.

Further, by forming annular concave portions 21a on the cylindrical surface of the guide roller 21 at a total of three places at a central portion in a longitudinal direction and both end portions thereof, as shown in FIG. 65, an air film F is generated between the annular concave portions 2.
1a.

Therefore, the magnetic tape 65 can be prevented from floating from the cylindrical surface of the guide roller 21, and the adhesion between them can be increased to increase the frictional resistance. As a result, the friction contact area based on the holding angle can be used effectively, and the ability of the guide roller 21 to follow the magnetic tape 65 can be increased to reduce slip.

As described above, the surface roughness of the cylindrical surface of the guide roller 21 does not need to be so large, and the surface roughness of the cylindrical surface of the guide roller 21 is set to Rz = 0.8 μm.
Even in the vicinity of m, the slip with the magnetic tape 65 can be reduced, so that the possibility of damaging the surface of the magnetic tape 65 can be significantly reduced.

The surface roughness Rz is determined by the so-called ten-point average roughness method, that is, the average value of the highest to fifth peaks in the cross-sectional curve of the roughness measurement result and the lowest to fifth peak. A method is used in which the difference from the average value of the valley heights is expressed in μm.

The conditions for measuring the surface roughness are all based on the following conditions. That is, cutoff = 0.25 mm Measurement length = 0.8 mm Magnification ratio = 10,000 times Diameter of probe = 2 μm Tracing speed = 0.03 mm / s Chart speed = 1.5 mm / s

The number of revolutions of the guide roller during recording / reproduction is usually 400 to 500 rpm. p. m, but F
The number of rotations during F (fast feed) and REW (rewind) is usually
14,000 to 15,000 r. p. m.
In order to prevent the surface of the magnetic tape from being damaged during such FF or REW, the rotation speed of the guide roller should be at least 2,000 rpm. p. m or more.

However, conventionally, when the surface roughness of the cylindrical surface of the guide roller is Rz = 2 μm, the rotation speed during FF or REW is 0 to 10,000 rpm. p. m (see FIG. 12), and when the surface roughness is Rz = 5 μm, the rotation speed during FF or REW is 800 to 12,000 r.p.m. p. m
(See FIG. 13), and especially their minimum rotation speed is 2,000 r.p.m. p. m, and the surface of the magnetic tape is still likely to be damaged.

However, according to the first embodiment of the present invention, as described above, the surface roughness of the cylindrical surface is set to Rz = 0.8 μm.
m, and the guide roller 21 having the annular concave portion 21a formed in the cylindrical surface is used, so that the rotation speed at the time of FF or REW is 2,300 to 12,000 rpm as shown in FIG. p.
m, and the minimum rotation speed is 2,000 r. p. m or more, the possibility that the surface of the magnetic tape 65 is damaged can be significantly reduced.

Incidentally, in FIGS.
As the number of revolutions at the time of REW approaches the end of the winding time, the number of the tapes on the tape reel 63 at the beginning and end of the winding of the magnetic tape 65 is remarkably larger than before. Is changed. For example, as shown in FIG. 10, even if the diameter of the magnetic tape 65 initially wound on the tape reel 63 is large (FIG. 10 (a)), the magnetic tape 65 is rapidly wound on an adjacent tape reel (not shown). At the end, the diameter of the magnetic tape 65 becomes smaller (FIG. 10B).

As a result, the contact angle (holding angle) of the magnetic tape 65 with the guide rollers 21 and 71 corresponding to the tape reel 63 is reduced, and the guide rollers 21 and 7 are reduced.
1 and the magnetic tape 65, the contact area thereof is reduced, and the magnetic tape 65 almost passes on the tangent to the cylindrical surface of the guide rollers 21 and 71.
The air between 71 and the magnetic tape 65 escapes easily.

For this reason, by preventing the magnetic tape 65 from floating from the cylindrical surface of the guide rollers 21 and 71 and increasing the adhesion between them, the guide rollers 21 and 71 are improved.
Since the followability of the magnetic tape 65 to the magnetic tape 65 can be improved, the number of rotations of the guide rollers 21 and 71 at the end of the winding of the magnetic tape 65 is significantly higher than before.

FIG. 4 is a graph showing the relationship between the surface roughness and the minimum number of revolutions of the guide roller 21 according to the first embodiment of the present invention. From the figure, it can be seen that the minimum rotation speed is 2,000 r. p. It can be seen that in order to achieve m, the surface roughness must be at least Rz = 0.5 μm or more. From this, in the first embodiment of the present invention, the surface roughness of the guide roller 21 is set to Rz = 0.6 to
It is set to 1.0 μm.

FIG. 5 is a view showing a second embodiment of the present invention. FIG. 5 shows a guide roller 31 which is a molded product using a plastic material such as polyacetal resin. In the case where the guide roller 31 is formed by die molding as described above, cooling is performed in the die after injection molding of the molten plastic material into the die. Due to the mold structure, cooling is performed from both the outer peripheral surface side and the end surface side of the cylindrical shape.
The cooling is performed faster than the other portion at the center of the longer length, and as a result, the amount of shrinkage at the corners C at both ends is smaller than at the other portion. For this reason, the corners C at both ends are larger in diameter than the other portions, and the cross section between the other portions is formed in an arc shape.

In the case of forming by the above-mentioned mold molding, the shrinking position and the shrinkage amount of the mold molded product are determined by the molding conditions such as the temperature of the mold and the molten plastic material, the injection pressure of the plastic material, or the cooling time. Some control. In the second embodiment, the arc-shaped length L from the end face of the guide roller 31 is set to 2 to 3 mm, and the difference S in diameter on one side is set to 40 to 50 μm.

As shown in FIG. 5, the thickness of the central portion in the length direction of the guide roller 31 is made larger than the thickness of the adjacent portions thereof, and the thick portion is formed in an annular shape. Since the cooling rate of the thick part in the mold is lower than that of the adjacent parts, the shrinkage is larger than that of the adjacent parts.

For this reason, an annular concave portion 31a is formed on the outer peripheral surface at the central portion in the length direction of the guide roller 31 so as to be recessed from its adjacent portions. The depth d of the recess 31a is also
It is possible to control to some extent by adjusting the wall thickness and other conditions, and by setting the depth d to several tens of μm, the same effect as in the first embodiment can be obtained.

In the first embodiment,
The case where the annular concave portions 21a are formed at three places in the length direction of the cylindrical surface of the guide roller 21 has been described. However, only one annular concave portion 21a may be provided at the central portion in the longitudinal direction. Alternatively, it may be two or four or more.
Further, a large number of the annular concave portions 21a may be provided in detail, but they must be kept within a range that does not damage the surface of the magnetic tape.

In the second embodiment, the guide roller 31 is made of a polyacetal resin having excellent heat resistance and abrasion resistance. However, the guide rollers 21 and 31 may be made of other plastic materials. Alternatively, any other material, such as metal, may be used.

[0045]

As described above, according to the tape cassette apparatus of the present invention, by setting the surface roughness of the cylindrical surface of the guide roller near Rz = 0.8 .mu.m, the conventional structure is improved.
The surface roughness is greatly reduced as compared with the case where it is difficult to reduce the thickness from around μm, and thus the possibility of damaging the surface of the magnetic tape can be significantly reduced.

Further, by forming an annular concave portion on the cylindrical surface of the guide roller, even if an air film is generated between the guide roller and the magnetic tape, the air of the air film is allowed to escape from the annular concave portion. Can be.

For this reason, the magnetic tape is prevented from rising from the cylindrical surface of the guide roller, the adhesion between the two is increased, the frictional resistance is increased, and the guide roller follows the magnetic tape, so that the slip is reduced. Can be done.

As described above, even if the surface roughness of the cylindrical surface of the guide roller is around Rz = 0.8 μm, the slip between the guide roller and the magnetic tape can be reduced, so that the surface of the magnetic tape may be damaged. Can be significantly reduced.

Further, according to the first embodiment, the surface roughness of the cylindrical surface is set to around Rz = 0.8 μm, and
By using the guide roller 21 having two annular concave portions 21a, the minimum number of rotations at the time of FF or REW is 2,
000r. p. m or more, the possibility that the surface of the magnetic tape 65 is damaged can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a guide roller 21 according to a first embodiment of a tape cassette device according to the present invention.
(A) is a lateral side view and a partially enlarged sectional view thereof, FIG.
FIG. 2B is a right front view of the guide roller 21 in FIG.

FIG. 2 is a partial cross-sectional longitudinal side view showing a positional relationship between a guide roller 21 and a magnetic tape 65 in FIG. 1 and a partially enlarged cross-sectional view thereof.

FIG. 3 shows the rotation speed, FF and REW of the guide roller 21.
It is a graph which shows the relationship with the winding time at the time.

FIG. 4 is a graph showing a relationship between a minimum rotation number of a guide roller 21 and a surface roughness of a cylindrical surface thereof.

FIG. 5 is a vertical side view of a guide roller 31 showing a second embodiment of the present invention and a partially enlarged sectional view thereof.

FIG. 6 is an exploded perspective view of a conventional tape cassette device.

FIG. 7 is a top view of a conventional lower half case portion 53.

FIG. 8 is a plan view of a conventional upper half case portion 51.

9A and 9B are views showing a conventional guide roller 71, FIG. 9A is a lateral side view thereof, and FIG. 9B is a right front view of the guide roller 71 in FIG. 9A.

FIG. 10 shows a conventional tape reel 63, a magnetic tape 65,
FIG. 10A is a top view showing a positional relationship between the magnetic tape 65 and the guide roller 71. FIG.
10B is a diagram showing a state where a large amount of magnetic tape 65 is wound around a tape reel 63. FIG.

FIG. 11 shows a conventional guide roller 71 and a magnetic tape 65.
1 is a partial cross-sectional vertical side view and a partially enlarged cross-sectional view thereof.

FIG. 12 shows that the surface roughness of a conventional guide roller 71 is Rz.
6 is a graph showing the relationship between the number of rotations when = 2.0 μm and the winding time during FF and REW.

FIG. 13 shows that the surface roughness of a conventional guide roller 71 is Rz.
7 is a graph showing the relationship between the number of rotations when = 5.0 μm and the winding time during FF and REW.

[Explanation of symbols]

21, 31, 71 ... guide rollers, 21a, 31a ...
Recess, 21b: shaft hole, 50: tape cassette device, 51
... Upper half case part, 51a ... mating part, 53 ... lower half case part, 53a ... mating part, 55 ... reel stand insertion hole, 57 ... reel hub, 59 ... lower reel plate, 61 ... upper reel plate, 63 ... tape reel , 65 ... magnetic tape, 67
... tape guide, 69 ... guide pin, 71 ... guide roller, 73 ... reel lock, 76 ... lid lock, 80
... bottom part, 82 ... virtual cylindrical surface, 84 ... reel insertion part inner wall,

Claims (5)

[Claims] 1. A case part comprising an upper half case part and a lower half case part; one recording tape wound between two tape reels housed side by side in the case part; A guide roller having a cylindrical surface rotatably provided between the lower half case portions and rotating in contact with the running recording tape; anda tape cassette device comprising: a surface roughness of the cylindrical surface of the guide roller. Rz = 0.8
A tape cassette device having a diameter of about μm and an annular recess formed in a cylindrical surface of the guide roller. 2. The tape cassette device according to claim 1, wherein said guide roller is formed of polyacetal resin. 3. The tape cassette apparatus according to claim 1, wherein the annular concave portion is formed so that an annular edge is not formed on a cylindrical surface of the guide roller. 4. The tape cassette device according to claim 1, wherein the annular concave portion is formed on a cylindrical surface of the guide roller by machining. 5. The tape cassette device according to claim 1, wherein the annular concave portion is formed in a cylindrical surface of the guide roller by die injection molding.