JPH0850774A - Tape cassette - Google Patents

Abstract

PURPOSE:To reduce generation of tape damage and to stably run a tape by rapidly self-aligning with a guide roller. CONSTITUTION:A contacting part 11a protruding on the inner surface of a center hole 11A where a roller shaft 9 is inserted of a guide roller 10 is formed to have an arcuate section, thus mounting to a shaft so that the guide roller 10 can rotate freely while it is in nearly line contact with the roller shaft 9. With the contacting part 11a, an upper circular surface and a lower circular surface are asymmetrical for axial direction for a top part.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a tape cassette,
Particularly, the present invention relates to a tape cassette provided with a guide roller having an automatic centering function for automatically centering a running tape.

[0002]

2. Description of the Related Art For example, a tape cassette for PCM signal recording has a width, depth and thickness of about 30 m.
It is provided with a so-called postage-stamp size cassette housing having a size of m × 21.5 mm × 5 mm. The cassette housing has an opening on the front side, and the opening is opened and closed by the lid. Both ends of the lid are rotatably supported on the side surfaces of the cassette housing, and when the tape cassette is loaded in the tape deck, the lid is rotated up and down to open the opening.

A pair of left and right hubs around which tapes (magnetic tapes) are wound are rotatably housed in the cassette housing so as to correspond to the pair of left and right hub drive shaft insertion holes formed on the upper and lower surfaces. In addition, roller shafts are provided upright on the left and right sides of the opening in the cassette housing, and guide rollers (pinch rollers) are rotatably mounted on these roller shafts. The tape is drawn out from one hub and hung on one guide roller, extended to the back side of the lid, hung across the opening and hung on the other guide roller, and then wound around the other hub. .

The tape cassette thus constructed is
An information signal is recorded on the tape or a reproduction of the information signal recorded on the tape is performed by the helical scan method by the rotary head drum device on the tape deck side. The rotary head drum device is configured such that the rotary head (magnetic head) is rotated at a required angle with respect to the head drum 32.

When the tape cassette is loaded in the tape deck, the head drum of the rotary head drum device enters from the opened opening, and the tape traversing the opening is slidably contacted so as to wind around the outer peripheral surface, A helical scan is performed by the rotary head to record and reproduce an upper signal. The tape has a margin to move up and down to some extent inside the cassette housing, and the tension in the width direction also changes momentarily due to the influence of one-sided extension of the edge portion due to running.

In the above-mentioned tape cassette, as a means for stably running the tape in the above-described state to the center (regulated center) of the cassette housing, for example, Japanese Patent Application No.
An automatic centering mechanism for the guide roller disclosed in Japanese Patent No. 285266 is provided. In this guide roller self-centering mechanism, as shown in FIG. 8, a roller shaft 9 for rotatably supporting the guide roller 10 has a shaft main body 9a and the shaft main body 9a.
It is composed of pedestals 9b and 9c on the upper half 2 and lower half 3 sides that are formed to have a larger diameter. The guide roller 10 is composed of a cylindrical holder 11 that is rotatably mounted on a roller shaft 9 that is inserted through a center hole 11A, and a rubber body 12 that is fixed to the outer periphery of the holder 11.

The holder 11 is made of synthetic resin as a material and is formed into a cylindrical shape. The holder 11 is provided at the center of the inner peripheral surface of the center hole 11A.
A receiving portion 11a that receives the shaft main body portion 9a of the roller shaft 9 is formed to continuously project in the circumferential direction. This receiving portion 11a
Is formed to have an inner diameter slightly larger than the diameter of the shaft body 9a of the roller shaft 9, so that a slight gap is formed between the roller shaft 9 and the shaft body 9a. Therefore, as shown in FIG. 9A, the guide roller 10 can be slightly swung with respect to the roller shaft 9 around the receiving portion 11a.

When the tape cassette is loaded in the tape deck, and the capstan 40 on the tape deck side is pressed against the guide roller 10 as shown in FIG. The guide roller 10 swings around the receiving portion 11a by the pressing force of the capstan, so that the tape T is automatically aligned. As a result, the tape T is stably run while being centered on the defined center of the cassette housing 1.

[0009]

The guide roller 10 having the self-centering function described above has a portion of the holder 11 that abuts on the roller shaft 9, that is, the outer peripheral surface of the shaft body 9a of the roller shaft 9. The receiving portion 11a on the inner peripheral surface and the upper and lower receiving portions 11b and 11c of the holder 11 that come into contact with the pedestal portions 9b and 9c formed above and below the roller shaft 9 are configured to be in surface contact with each other.

By the way, the guide roller 10 sufficiently exhibits the above-mentioned self-aligning function (pivoting function) in response to a change in tension of the traveling tape T or a pressing force of the capstan on the tape deck side. The roller shaft 9
It is preferable that the abutting portion with and is formed in a shape that makes the guide roller 10 itself easy to move. However,
In the above-mentioned prior application guide roller 10, the receiving portion 11
Since a and the receiving portions 11b and 11c are brought into contact with the roller shaft 9 in a surface contact state, there is a problem that a sufficient self-aligning action cannot be achieved.

Therefore, the present invention has been proposed for the purpose of providing a tape cassette configured so that the guide roller can quickly perform the self-aligning action to reduce the occurrence of tape damage and to run in a stable state. It is a thing.

[0012]

A tape cassette according to the present invention which achieves this object is a roller shaft provided in a cassette housing, and a cylindrical guide roller rotatably mounted on the roller shaft. And a tape guide mechanism for automatically aligning the running tape.
The guide roller is integrally formed with an abutting portion having an arcuate cross-section that abuts the outer peripheral surface of the roller shaft on the inner peripheral surface.

[0013]

According to the tape cassette of the present invention configured as described above, the guide roller having the roller shaft inserted therein has the contact portion integrally projecting on the inner peripheral surface with the outer peripheral surface of the roller shaft. It comes into line contact with and is rotatably supported. The guide roller has a small frictional resistance at the abutting portion with respect to the roller shaft, so that the swinging operation is smoothly performed and more effective self-centering property is obtained, and the tape is centered quickly.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. Example P shown in FIGS. 5 to 7
The tape cassette for recording a CM signal includes a so-called stamp size cassette housing 1 like the conventional tape cassette described above. As shown in FIG. 5, the cassette housing 1 is configured by integrally assembling an upper half 2 and a lower half 3 by tightening a set screw 4. The cassette housing 1 has an opening 5 on the front side thereof, and the opening 5 is opened and closed by a lid 6. Both ends of the lid 6 are rotatably supported by the side surfaces of the cassette housing 1 so that the lid 6 can be rotated up and down, and normally the opening 5 is closed.

The cassette housing 1 has a pair of left and right hub drive shaft insertion holes 7, 7 into which the hub drive shafts on the tape deck side enter, on the upper and lower surfaces. Inside the cassette housing 1, a pair of left and right hubs 8, 8 around which the tape T is wound are rotatably accommodated in correspondence with the hub drive shaft insertion holes 7, 7.

In the cassette housing 1, as shown in FIG.
Roller shafts 9 and 9 are provided upright on both left and right sides of the opening 5, and guide rollers 10 and 10 are rotatably mounted on the roller shafts 9 and 9, respectively. Tape T
Is pulled out from one hub 8 and is engaged with one guide roller 10. The tape T is extended to the back side of the lid 6 and traverses the opening 5 to guide the other guide roller 1.
After being multiplied by 0, it is wound around the other hub 8.

The cassette housing 1 is internally provided with a brake mechanism 14 for restricting the rotation of the left and right hubs 8, 8 to prevent the tape from loosening when the tape cassette is not used. The cassette housing 1 has erroneous erasure prevention members 15 exposed on the upper and lower surfaces thereof, a positioning reference hole 16 and various detection holes 17, and grips 18 on the left and right side surfaces. ing. Lid 6
An engaging tooth portion 20 for an automatic changer is formed along the guide groove 19 in the construction direction.

The tape cassette thus constructed is
An information signal is recorded on the tape T or the information signal recorded on the tape T is reproduced by the helical scan method by the rotary head drum device 30. As shown in FIG. 6, the rotary head drum device 30 is configured so that a rotary head (magnetic head) 31 is rotated while being inclined at a required angle with respect to the head drum 32.

When the tape cassette is loaded on the tape deck, the lid 6 is rotated upward or downward by the lid opening means on the tape deck side, and the closed opening 5 is opened. The head drum 32 of the rotary head drum device 30 enters the opened opening 5. The tape T traversing the opening 5 is slidably contacted with the head drum 32 so as to wind around the outer peripheral surface. The tape T is helically scanned by the rotary head 31 that rotates when a recording operation or a reproducing operation is performed.

In order to ensure that the tape T is slidably contacted with the outer peripheral surface of the head drum 32, the cassette housing 1 has an arcuate portion corresponding to the head drum 32 at the back of the opening 5 as shown in FIG. A pair of left and right self-alignment guides 21, 21 are attached swingably. These self-alignment guides 21 and 21 are in a state of receiving the outer peripheral portion of the head drum 32 that has entered the opening 5, and guide the tape T between the outer peripheral surface of the head drum 32 and the peripheral surface of the drum reliably. It has the effect of causing it.

On the other hand, as shown in FIG. 6, the rotary head drum device 30 is provided with wing guides 33, 33 projecting to both left and right sides of the head drum 32. Rollers 33a and 33a are attached to the tip ends of these wing guides 33 and 33, respectively. At the same time when the head drum 32 enters the opening 5 of the tape cassette, the wing guides 33 and 33 relatively engage with the self-alignment guides 21 and 21 to fix and hold the self-alignment guides 21 and 21, and at the tips of the wing guides 33 and 33. The provided rollers 33a and 33a guide the tape T between the self-alignment guides 21 and 21.

When the tape cassette is loaded in the tape deck, the hub drive shaft on the tape deck side enters into the insertion hole 7 and relatively engages with the hub 8, and the capstan is inserted from the front of the cassette housing 1. Are pressed against the outer peripheral surface of the guide roller 10 with the tape T in between. The tape T is driven by rotating the hub drive shaft and the capstan. The tape T has a margin to move up and down within the cassette housing 1 to some extent, and the tension in the width direction also changes momentarily due to the one-sided extension of the edge portion due to running.

In the tape cassette, the tape guide mechanism exerts an automatic centering action for preventing the tape T from running in an unstable state due to a change in tension of the tape T in the width direction. The tape guide mechanism is
The roller shaft 9 is provided on both sides of the opening 5 and stands upright on the lower half 3, and the guide roller 10 is rotatably mounted on the roller shaft 9.

As shown in FIG. 1, the roller shaft 9 includes a shaft main body 9a having an outer peripheral surface formed into a smooth surface, and the shaft main body 9a.
Upper half 2 that is made a little larger than a and is integrally formed
And the pedestals 9b and 9c on the lower half 3 side. The roller shaft 9 has a length substantially equal to the height of the cassette housing 1, and is supported between the upper half 2 and the lower half 3.

The guide roller 10 is made of synthetic resin and has a cylindrical holder 11 having a central hole 11A.
And a rubber body 12 fixed to the outer peripheral portion of the holder 11. As shown in FIG. 1, the holder 11 has an axial length that is slightly smaller than the entire axial length of the roller shaft 9, and is also slightly larger than the shaft body 9a. Further, in the holder 11 mounted on the roller shaft 9 as will be described later, the inner diameters of the upper and lower portions of the central hole 11A corresponding to the pedestal portions 9b and 9c are larger than the outer diameters of the pedestal portions 9b and 9c, respectively. The diameter of the shaft body is slightly larger, and the central portion corresponding to the shaft body 9a is formed as a stepped hole slightly larger than the outer diameter of the shaft body 9a.

Further, in the holder 11, an abutting portion 11a is integrally provided on the inner surface of the central hole 11A at a substantially central portion in the axial direction so as to circumferentially surround the holder 11a. The contact ribs 11b and 11c are integrally formed. The holder 11 has locking flanges 11d on the outer peripheral edges of both ends,
11e is integrally provided around the circumference. Contact part 11a
The contact ribs 11b and 11c are each formed to have an arc-shaped cross section.

The contact portion 11a and the contact rib 11b,
Reference numeral 11c denotes an inner surface of the center hole 11A of the holder 11, an outer peripheral surface of the shaft main body portion 9a of the roller shaft 9, a step portion, and base portions 9b and 9c.
Although the height dimension can be arbitrarily set within the range of the facing distance between the tape cassette and the tape cassette, the height of the cassette housing 1 is formed to be too large due to the size restriction of the embodiment tape cassette configured as a stamp size. Of course, there are things that cannot be done.

In the tape cassette of the embodiment, the contact portion 11a has a height dimension H ₁ from the inner surface of the center hole 11A to the apex portion of 0.05 mm to 0.2 mm. Further, the contact ribs 11b and 11c are set such that the height dimension H ₂ from the main surface of the stepped portion to the apex portion is in the range of 0.01 mm to 0.1 mm.

The holder 11 constructed as described above includes
Both ends are locked by the locking flange portions 11d and 11e, and the rubber body 12 is fixed to the outer peripheral portion, whereby the guide roller 10 is configured. The holder 11 is rotatably mounted on the roller shaft 9 by penetrating the roller shaft 9 through the center hole 11A.

When the guide roller 10 is mounted on the roller shaft 9, the contact portion 11a of the holder 11 contacts the outer peripheral surface of the shaft body 9a, and the contact rib 11 has a contact rib 11a.
b and 11c contact the pedestals 9b and 9c. The contact portion 11a and the contact ribs 11b and 11c are rotatably supported in line contact with the roller shaft 9 because the contact portions 11a and the contact ribs 11b and 11c have an arc-shaped cross section as described above.

Therefore, the tape guide mechanism has a structure in which the frictional resistance between the roller shaft 9 and the guide roller 10 is reduced, so that the guide roller 10 rolls in accordance with the change in the tension of the tape T in the width direction. The tape T is swiftly centered by oscillating the shaft 9 with good responsiveness.

In the tape cassette of the embodiment, since the tape guide mechanism quickly centers the tape T in this way, the edge of the tape T shortens the time of the contact resistance received inside the cassette housing 1 to reduce the edge damage. Is reduced, and for example, the occurrence of powder falling phenomenon that hinders the reproduction characteristic is reduced. Further, in the tape cassette, since the tape T is run in a stable state by the tape guide mechanism, the tape T is evenly rubbed against the head drum 32, so that the information signal is accurately recorded or reproduced.

The holder 11 which constitutes the guide roller 10 of the above-described tape guide mechanism has, for example, a molten resin in a pair of upper and lower molds 50 and 51 in which a cavity having the same shape as the holder 11 is formed as shown in FIG. Is molded by injection. The upper die 50 forms an upper portion of the holder 11, and the lower die 51 abutted on the upper die 50 forms a lower portion of the holder 11. The upper mold 50 and the lower mold 51 are the holder 1
In the outer peripheral portion of No. 1, the inner peripheral edge of the upper locking flange portion 11d is butted.

Therefore, the holder 11 is forcibly removed from the lower die 51 at the lower engagement flange portion 11e. The holder 11 includes an upper mold 50 and a lower mold 51 at the time of molding.
As described above, the height dimension H ₂ of the contact ribs 11b and 11c is 0.
It is set to 01 mm to 0.1 mm.

In the upper mold 50 and the lower mold 51, in the central hole 11A portion of the holder 11, it is preferable that the apex of the abutting portion 11a be the abutting position (parting line) PL. In the molding process, generally, a step or a burr is likely to occur on the parting line PL between the upper mold 50 and the lower mold 51. Since the contact portion 11a is a portion that contacts the shaft main body portion 9a of the roller shaft 9 as described above, it needs to be configured as a highly accurate smooth surface.
Is manufactured with high precision.

In order to obtain the contact portion 11a having a high surface accuracy, a contact portion cavity is formed on either side of the upper die 50 or the lower die 51 so that the upper die 50 and the lower die 51 are separated from each other. A molding die in which the parting line PL is shifted in the axial direction may be adopted. However, in such a molding die, the contact portion 11a is forcibly removed when the holder 11 after the molding process is removed. The contact portion 11a is deformed by forcible removal, which causes a problem that predetermined accuracy cannot be obtained.

The holder 11 is basically arranged so that the parting line PL of the upper die 50 and the lower die 51 is located at the apex C of the abutting portion 11a, but as shown in FIG. Up to a position shifted by Δx. In other words, in the holder 11, the position of the parting line PL between the upper die 50 and the lower die 51 is such that the contact portion 1
The height ΔH is allowed up to a position in the range of ΔH = 0 to 0.05 mm from the apex of 1a. Holder 11
In the range of the deviation height ΔH of the parting line PL, even if the contact portion 11a is forcibly removed after molding, the contact portion 11a is not deformed and the surface accuracy is improved. Holding is performed and molding is performed.

Therefore, the holder 11 has the abutting portion 11a which is held with high accuracy without causing the disadvantage that the molding burr is generated or deformed on the surface by the upper mold 50 and the lower mold 51. Is molded. Contact part 11a
Is formed by having the arcuate surface asymmetric with respect to the axial direction by shifting the position of the parting line PL of the molds 50, 51 from the apex portion in the axial direction.

By the way, in the upper mold 50 and the lower mold 51, a concave part having a semi-circular cross section for forming a contact part cavity is formed at the tip of the axial convex part forming the center hole cavity of the holder 11. It is formed around each. These shaft-shaped protrusions are holders 1 provided in a microminiature tape cassette.
Since it is a member that forms one central hole 11A, it has an extremely small diameter as a whole. Therefore, the processing of the highly accurate semi-circular concave portion provided on the tip portion of the axial convex portion is
It will be extremely difficult. In the process of forming the semi-circular concave portion at the tip of the shaft-shaped convex portion, it is generally difficult to obtain a uniform curvature as a whole, and the curvature on the proximal side becomes smaller than the curvature on the distal side. I will end up.

Due to such machining characteristics, the holder 11 is formed such that the contact portion 11a is formed such that the curvature RS at the top and bottom portions is RL> RS with respect to the curvature RL at the apex portion. Become.

The present invention is not limited to the above-mentioned ultra-compact tape cassette for PCM recording, but it is needless to say that it can be widely applied to tape cassettes having a built-in guide roller. Further, it goes without saying that the present invention is not limited to the structures shown in the embodiments, and can be appropriately modified based on the technical idea of the present invention.

[0042]

As described above, according to the tape cassette of the present invention, the tape guide mechanism having the self-centering function is provided in the cassette housing, and the center hole of the guide roller constituting the tape guide mechanism is provided. Since the abutting portion projecting on the inner surface of the roller and abutting on the outer peripheral surface of the roller shaft has an arc-shaped cross section, this guide roller is rotatably supported on the roller shaft in a line contact state, and friction resistance is reduced. In response to changes in the running tension of the tape, the swinging motion of the guide roller is quickly performed to perform self-centering action and center the tape. Therefore, in the tape cassette, the contact resistance time that the edge portion of the tape receives inside the cassette housing is shortened, so that the edge damage is reduced, the magnetic powder falls, and the reproduction characteristics are impaired. Is reduced. Further, in the tape cassette, the tape tension is adjusted by the tape guide mechanism over the entire width of the tape and the tape cassette is run in a stable state. Therefore, the tape is evenly rubbed against the head drum to record or reproduce the information signal. To do exactly. Further, according to the tape cassette of the present invention, the abutting portion projecting on the inner surface of the central hole of the guide roller constituting the tape guide mechanism is formed by a precise arc surface without forming burrs or the like on the surface. By being formed, the self-centering action for the tape is more efficiently achieved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part for explaining the configuration of a tape guide mechanism provided in an embodiment of a tape cassette according to the present invention.

FIG. 2 is a semi-longitudinal sectional view of a guide roller that constitutes the same tape guide mechanism.

FIG. 3 is a longitudinal sectional view of an essential part for explaining the configurations of a holder and a molding die that form the tape guide.

FIG. 4 is a longitudinal sectional view of a main part showing another embodiment of the holder.

FIG. 5 is a perspective view of an example tape cassette.

FIG. 6 is a perspective view illustrating the relationship between the tape cassette and the head drum.

FIG. 7 is a plan view showing a state where the upper half of the tape cassette is removed.

FIG. 8 is a longitudinal sectional view of an essential part for explaining the configuration of a tape guide mechanism provided in a conventional tape cassette.

9A and 9B are explanatory views of the automatic centering operation of the tape by the tape guide mechanism. FIG. 9A shows a state before the tape guide and the tape and the capstan are in contact with each other, and FIG. Shows a state in which the automatic centering operation of the tape is performed.

[Explanation of symbols]

 T tape 1 cassette housing 9 roller shaft 9a shaft body 9b, 9c pedestal 10 guide roller 11 holder 11A center hole 11a abutment 11b, 11c abutment rib 12 rubber body 50 upper die 51 lower die

Claims (3)

[Claims] 1. A tape guide mechanism comprising a roller shaft provided in a cassette housing and a guide roller rotatably mounted on the roller shaft, wherein the guide roller has a roller on its inner peripheral surface. An abutting portion having an arcuate cross-section that abuts the outer peripheral surface of the shaft is integrally formed so as to project, and the abutting portion rotatably mounts the roller shaft in a substantially linear contact state. Tape cassette. 2. The abutting portion is formed by having an arcuate surface in which an upper arcuate surface and a lower arcuate surface are asymmetrical with respect to the axial direction with respect to the apex portion. Item 2. The tape cassette according to Item 1. 3. The guide roller is formed of a synthetic resin material, and the abutting position of a die forming a central hole through which the roller shaft is inserted is within a range of 0 mm to 0.05 mm with respect to the apex of the abutting portion. The tape cassette according to claim 1 or 2, wherein the tape cassette is set.