JPH08124349A - Tape cartridge - Google Patents

Abstract

PURPOSE: To improve the surface characteristic of a tape guide and the assemblability of a tape cartridge by forming a butting recessed part generated owing to the plastic deformation on a part of peripheral surface of the tape guide. CONSTITUTION: A stainless material is drawn out by a specified dimension and pressurized with a jig for forming a cylinder after punched by using a punching jig, then the tape guide 11 provided with the recessed part 13 generated by the plastic deformation is formed. Next, the surface of the tape guide 11 is polished. When the tape guide 11 is engaged with a boss 12 provided on a lower case 1b, the positional control of a joint is unrequired on account of the presence of the recessed part 13, and the running of tape is not adversely affected even though the difference in level is generated on the joint part, since the end surface part of the joint is housed in the recessed part 13. Meanwhile, the thickness of the butting end surface of the tape guide 11 is nearly a half of the thickness of other parts, and the surface roughness smaller than 0.3μm in the average roughness of ten points is preferable for the cylinder surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cartridge applied to a recording / reproducing apparatus such as a video tape recorder, and more particularly to a cylindrical tape guide for guiding tape running. is there.

[0002]

2. Description of the Related Art The tape cartridge shown in FIG.
-It is a so-called C-cassette, which is miniaturized to be suitable for outdoor users. This tape cartridge is made of a plastic upper case 1a and a lower case 1b.
The tape casings 3 and 4 around which the tape 2 is wound are rotatably arranged on the left and right sides of the inside of the main body case 1 in which the tapes are butted and integrally coupled, and the tape 2 is attached to one reel 3 Kara lower case 1b
A tape guide 11 is attached to a boss 12 that is integrally provided upright from the bottom wall of the front side of the, and the cable is inserted through the tape guide 11.
The other tape guide 1 that is extended to the tape-producing pocket 5 on the front side of the shoe and is mounted on the boss 12 similar to the above.
It is designed to be wound around reel 4 via 1.

In recent years, there has been a strong demand from the market for a longer video time, and in order to meet those demands as a video tape, the tape thickness tends to be thinner than the conventional one. .

On the other hand, in this type of tape cartridge, price competition is intensifying, and in order to survive the market competition, the cost of the component parts is infinitely reduced while maintaining the conventional quality. The need to do so is also being cried.

Under such circumstances, the conventional technique
Because of the need for a highly accurate tape guide to cope with thinner tape, there have been few attempts to reduce the cost like other components of the tape cassette.

However, with the recent progress of processing technology, stable tape running can be obtained even when the tape is thinned, and the processing cost of the tape guide is reduced as compared with the conventional one. A tape guide as shown in FIGS. 3 (a) and 3 (b) has been proposed. These things are
Since the tape guide material is processed into a cylindrical shape by a predetermined method, the processing process is less complicated than that of drawing the tape guide material, and the material is better than that of drawing. The material cost of the tape guide material can be reduced, for example, the thickness of the tape guide is not required to a great extent.

More specifically, the tape guide 11 shown in FIG. 3 (a) is formed by processing a stainless steel plate material having an appropriate length into a cylindrical shape, welding the butt end faces, and then cutting the tape guide into a required length dimension. Then, as the surface finish, centerless polishing, super finish polishing, etc. are used to finish the surface property to a ten-point average roughness of 0.2 to 0.3 μm, and if necessary, chrome plating etc. On the other hand, in the tape guide shown in FIG. 3 (b), a stainless plate material is cut into a predetermined size and formed into a cylindrical shape by a forming die, and thereafter,
Surface property by barrel polishing is 0.7 to 1 μm in ten-point average roughness
Is finished.

In FIG. 3A, the surface property of the sliding contact surface of the tape is as good as 0.2 to 0.3 μm as described above,
Even if a back coat layer is provided on the back surface of the tape, the back coat layer is less likely to be scraped due to the accuracy of the abutting end faces, and stable tape running can be expected. There was a problem that the unit price was very high due to the process damage.

Further, in the case of FIG. 3 (b), the end face welding step can be omitted as compared with the case of FIG. 3 (a), so that the tape guide can be manufactured at low cost, but as shown in FIG. 3 (b). A seam 11b is generated due to the end faces abutting each other. Further close inspection reveals that there is a step at this joint that seems to be an error when abutting both end faces, and if a tape slides on this joint, it will be on the back of the tape. When the backcoat layer is provided, there is a problem that the backcoat layer is scraped off by the edge of the end face.

Therefore, as shown in FIG. 3 (b), a pair of notches 11a are provided on the upper and lower sides of the tape guide 11, while the base portion of the boss 12 for mounting the tape guide 11 of the lower case 1b. A rib 12a is provided to restrict the position of the seam position 11b of the tape guide. When mounting the tape guide 11 on the main body case 1, the position of the notch portion 11a of the tape guide 11 is regulated so as to fit with the rib 12a, and the joint portion 11b is slidably contacted with the tape. I try not to come to the surface. For this reason, not only the assembling device becomes complicated at the time of assembling the tape cartridge, but also when performing centerless polishing for improving the surface property, the step difference of the seam may hinder the supply of parts. ,or,
There was a problem that the rotary whetstone for polishing was caught on the step and the butt end face portion was opened.

From the above circumstances, it is possible to perform barrel polishing instead of centerless polishing, but in this case,
The surface property of the tape guide is 0.7 to 1.0 in ten-point average roughness.
Only those having a roughness of .mu.m can be polished, and the surface properties cannot be improved as much as the tape guide shown in FIG.

[0012]

The present invention basically relates to an improvement of the tape guide shown in FIG. 3 (b),
An object of the present invention is to provide a tape cartridge having improved surface properties of the tape guide and assembling property of the tape cartridge.

[0013]

According to the present invention, as a result of extensive studies on the tape guide 11 shown in FIG.
It has been found that as the guide 11, it is effective to form a butt recess 13 formed on a part of the peripheral surface by plastic deformation extending between the upper and lower end surfaces. This recess 13
Considering the edge shift when butting, when punching out the tape guide material, punch out so that the thickness of both ends of the butt is approximately half of the thickness of other parts, and improve the surface property. The surface roughness at this time is 0.3 μm or less in terms of ten-point average roughness, preferably 0.2 to 10 μm.
The thickness is set to 0.3 μm so that the same surface property as that of FIG.

[0014]

With the presence of the recess 13, it is not necessary to regulate the position of the seam when assembling the tape guide 11 to the main body case 1, and the tape guide 11 can be used in the conventional assembling apparatus.
Further, even if there is a step in the seam portion, the presence of the recessed portion 13 makes it possible to accommodate the end face portion of the seam in the recessed portion 13, so that the problem of adversely affecting the tape running can be eliminated.

As a means for forming the concave portion 13 in the present invention, a stainless material is drawn to a predetermined size and punched using a punching jig. After that, a jig is pressed so that the concave portions 13 are formed by plastic deformation on both end surfaces, and then a cylindrical shape is formed by using a predetermined jig, followed by centerless polishing and smoothing.
The surface finish of the tape guide is improved by polishing the finish.

As the tape guide material used in the present invention, brass material can be preferably used in addition to stainless steel material. In short, any material can be preferably used as long as it is plastically deformed during punching and is suitable for polishing to improve the surface property. Further, the depth of the recess 13 may be adjusted by arbitrarily adjusting the pressing force depending on the difference in punching material. For example, in the case of a stainless steel material, a pressurizing force of about 3 tons is required in order to make the thickness of both end faces of the butt approximately equal to the thickness of the other portions.

[0017]

EXAMPLES Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to only those examples.

The basic structure of the target tape cartridge is the same as that of the conventional example shown in FIG. In the tape guide 11 of the present invention, a stainless steel thin plate having a wall thickness of about 0.3 to 0.7 mm is pulled out by a predetermined dimension and cut, and both end portions which are the abutting end faces of the cut material are pressed. Press with a jig. At this time, both ends are plastically deformed, and the end face wall pressure after the deformation is processed into a shape having an inclined portion such that the wall pressure is approximately half of the wall pressure of the other part.

Next, this material is processed into a cylindrical shape by a cylindrical forming jig. In this process, the end faces are butted with each other to finally form the tape guide 11 having the recess 13 as shown in FIG. Further, the surface property of the tape guide was polished by centerless polishing so that the ten-point average roughness was 0.3 μm.

In the end face abutting process, a butt displacement may occur as in the conventional case, but even if the end face displacement occurs, the end face protrudes toward the tape sliding contact surface due to the presence of the recess. Since there is no fear, it does not hinder tape running and surface polishing. Moreover, FIG.
It is not necessary to form the notches 11a formed at both ends of the tape guide in (b), and there is no influence on the assembling of the tape cartridge.

Needless to say, the target tape cartridge is not limited to the illustrated example, but can be widely applied to other tape cartridges such as VHS tape cartridge.

[0022]

According to the present invention, due to the presence of the concave portion 13 formed by plastic deformation in the process of forming the tape guide 11, when the tape guide 11 is assembled to the main body case 1, a joint is formed. It is not necessary to regulate the position, the conventional assembling device can be used, and even if there is a step in the seam, the presence of the recess 13 causes the end face of the seam to be accommodated in the recess. Therefore, the problem of adversely affecting the tape running can be eliminated. In addition, the seam does not hinder the polishing work.

[Brief description of drawings]

FIG. 1 is a main part drawing showing a tape guide according to the present invention.

FIG. 2 is a plan view of a tape cartridge to which the present invention is applied.

FIG. 3 is a main part drawing showing a conventional tape guide.

Claims (4)

[Claims] 1. An upper and lower case 1a formed by butting each other.
.The reels 3 and 4 in which the tape 2 is wound are housed in the main body case 1 made of 1b, and the tape is fed in front of the main body case 1 from one reel. -Shaped tape guide 1 for restricting tape running so that the tape is wound on the other reel
In a tape cartridge having 1.11, the tape guide 1 is provided on a part of the peripheral surface as the tape guide 11.
1. A tape cartridge having a butted concavity 13 formed by plastic deformation extending between the upper and lower end surfaces of No. 1. 2. The tape cartridge according to claim 1, wherein the abutting end faces of the tape guides 11 and 11 have a wall thickness that is substantially half the wall thickness of other portions. 3. The tape cartridge according to claim 1 or 2, wherein the surface roughness of the cylindrical surface of the tape guides 11 and 11 is 0.3 μm or less in terms of ten-point average roughness. 4. The tape carriage of claim 3, wherein the surface roughness of the cylindrical surface of the tape guide 11 is 0.2 to 0.3 μm in terms of ten-point average roughness.