JPH04143982A - Disk cartridge - Google Patents

Abstract

PURPOSE:To easily and surely perform adhering work and to attain stability for quality by adhering a wear-resistance sheet on the inside surface of an upper half of a cartridge by adhesive of specific hardness. CONSTITUTION:The wear-resistance sheet 20 is adhered on the inside surface 1a of the upper half 1 of a disk cartridge consisting of the upper half and lower half by hot metal, adhesive 21. Assuming the adhesive 21 as the one of >=20 Short A hardness, direct adhesion can be performed, and the adhering work can be easily and surely performed without generating run or leakage, and also, the contact area of the sheet 20 with a spindle 10 can be prevented from increasing by the adhesive of prescribed hardness, which heightens the stability for the quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disk cartridge most suitable for use with a micro-floppy disk made of a magnetic sheet having a diameter of 3.5 inches, for example.

[Summary of the invention]

The present invention has a disk-shaped recording medium rotatably housed in a cartridge consisting of an upper half and a lower half, and a wear-resistant material that is bonded to the inner surface of the upper half at the tip of a spindle on which a center core of the disk-shaped recording medium is chucked. In a disc cartridge configured to be pressed against a wear-resistant sheet, durability can be improved, costs can be reduced, etc. by adhering the wear-resistant sheet to the inner surface of the upper half with an adhesive having a hardness higher than a certain level. This is how it was done.

[Conventional technology]

Regarding a disk cartridge using a micro-floppy disk, for example, Japanese Patent Application Laid-Open No. 57-36473 is known, and a conventional disk cartridge of this type was constructed as shown in FIGS. 7 and 8.

That is, a cartridge 3 is formed by the upper and lower halves 1.2 molded from synthetic resin, and within this cartridge 3 is a micro-floppy disk (hereinafter simply referred to as disk) made of a magnetic sheet with a diameter of 3.5 inches, which is a disk-shaped recording medium. 4) is rotatably housed. A center core 5 of the disk 4 made of a metal plate such as stainless steel is loosely fitted into a spindle insertion hole 6 formed approximately at the center of the lower half 2. In addition, at a position directly above the center of the spindle insertion hole 6, the inner surface 1a of the upper half 1 is provided with a wear-resistant sheet (called a center plate) formed of an ultra-high molecular weight polyethylene sheet, etc.
7 is double-sided adhesive tape (thickness is 130 μm)
μm)8.

When this disk cartridge is installed in a recording/reproducing apparatus, the spindle IO of the spindle motor 9 is inserted into the spindle insertion hole 6 relatively vertically from below, and the spindle 10 is inserted into the center hole 5a of the center core 5. The center core 5 is inserted into the eccentric hole 5b of the center core 5, and the center core 5 is magnetically chucked onto the turntable II fixed to the outer periphery of the spindle 10.
is inserted relatively from below.

At the same time, the tip lOa of the spindle IO is relatively pressed against the wear-resistant sheet 7 from below, and the upper half 1 is pushed upward by the spindle 10 in the direction of arrow a against elasticity, and A designed gap G is formed between the halves 1 and 2.

In this chucking state, the center core 5 is rotationally driven by the driving pin 2 which is rotationally driven together with the spindle 10 and the turntable 11, and the disk 4
A pair of upper and lower liner sheets 13 and 14 for cleaning are adhered to the inner surfaces Ia and 2a of the upper and lower halves L and 2.
The disk 4 is rotated while in contact with the disk 4, and recording and reproduction are performed on and from the disk 4 by a magnetic head (not shown).

At this time, the center core 5 is positioned relative to the spindle 10 by the friction torque of the disk 4 against the pair of upper and lower liner sheets 13,14. Since the friction torque changes depending on the gap G between the upper and lower halves 1.2, the accuracy of the gap G is very important.

Further, the wear-resistant sheet 7 is attached to the tip 10 of the spindle 10.
Rotation friction (rotational resistance) of the spindle 10 due to rotation of the spindle 10 by being directly pressed against the upper half 1 is reduced, and generation of abrasion powder due to abrasion of the upper half 1 is prevented.

Conventionally, in order to adhere the wear-resistant sheet 7 to the inner surface 1a of the upper half L, double-sided adhesive tape 8 and release paper 15 were pasted on the back side of the wear-resistant sheet 7, as shown in FIG. A circular shape is punched out from the hoop material 16, the release paper 15 is peeled off, and the wear-resistant sheet 7 is attached with double-sided adhesive tape 8.
was adhered to the inner surface 1a of the upper half 1.

[Problem to be solved by the invention]

However, in the conventional method of adhering the wear-resistant sheet 7, it takes many man-hours to punch out a circular shape from the hoop material 16, peel off the release paper 15 one by one, and adhere the wear-resistant sheet 7 to the upper half 1 with the double-sided adhesive tape 8. There are many cases where the adhesive work is very troublesome. Hoop material 16 with expensive double-sided adhesive tape 8 and release paper 15 pasted on the back side of wear-resistant sheet 7
is very expensive. The double-sided adhesive tape 8 has problems such as a short usage period (working life) and low durability.

Here, as shown in FIG. 10, it is possible to consider a method in which the wear-resistant sheet 7 is directly adhered to the inner surface 1a of the upper half 1 using an adhesive 1°7.

The following adhesives can be used as the adhesive 17.

(A) In the case of a type in which SBR rubber or the like is soaked in a solvent, it is difficult to control the thickness T of the adhesive, and the solid content is small, making it difficult to control the thickness T.

(B) Two-component adhesives such as epoxy and acrylic adhesives are difficult to handle and require a long curing time after bonding. Not suitable.

(C) The cyano-based bond, which is typical as an instant adhesive, has a small thickness T and is weak against shock, and the wear-resistant sheet 7 is damaged by the shock when the disk cartridge is attached and detached from the recording/reproducing device many times. Easy to peel off.

CD>, in particular, as shown in FIG. 10, when the adhesive 17 does not exceed a certain hardness,
When a is pressed against the wear-resistant sheet 7, the wear-resistant sheet 7 digs into the adhesive 17, and the tip 10a of the spindle 10 cannot push up the upper half 1 in the direction of the arrow a. In addition, it becomes impossible to form the designed gap G between the upper and lower halves 1.2 as shown in FIG. In addition, the contact area between the tip 10a of the spindle 10 and the wear-resistant sheet 7 increases extremely, causing the wear-resistant sheet 7 to easily wear out (not only that, but also the frictional resistance (rotational resistance) of the spindle 10 increases. This creates new problems such as

An object of the present invention is to provide a disk cartridge that can improve durability and reduce costs.

[Means to solve the problem]

In order to achieve the above object, the disk cartridge of the present invention has a wear-resistant sheet against which the tip of the spindle is pressed, adhered to the inner surface of the upper half with an adhesive such as a hot melt adhesive having a Shore A hardness of 20 or more. It is something.

[Effect]

In the disk cartridge configured as described above, the wear-resistant sheet can be directly adhered to the inner surface of the upper half with an adhesive without using a double-sided adhesive tape with release paper. Moreover, since the Shore A hardness of the adhesive is selected to be 20 or higher, when the tip of the spindle is pressed against the wear-resistant sheet, the amount of the adhesive biting into the inside of the wear-resistant sheet is extremely small. can.

〔Example〕

An embodiment in which the present invention is applied to a disk cartridge using a micro-floppy disk is shown in FIGS.
This will be explained with reference to FIG. Note that the same reference numerals are given to the same structural parts as in the conventional example shown in FIGS. 7 to 10, and redundant explanation will be omitted.

First, as shown in FIGS. 1 and 2, a wear-resistant sheet 20 with both a wire width and a width The wear-resistant sheet 20 is cut into a square shape W without wasting any waste, and the wear-resistant sheet 20 is placed approximately at the center of the inner surface 2a of the upper half 1 (right above the center of the spindle insertion hole 6 of the lower half 2) with Shore A hardness. They are directly bonded using a hot melt adhesive 21 having an adhesive of 20 or more.

The thickness T of the wear-resistant sheet 20 is 130 μm, and the thickness T2 of the true melt adhesive 21 is also 130 μm.
etc. with high precision. In addition, Shore A hardness refers to a hardness value obtained by the hardness measurement method specified by the Japan Adhesive Industry Association according to 7) Melt Adhesive Test Method. Moreover, the Shore A hardness is the value not immediately after adhesion of the wear-resistant sheet 20, but after 5 seconds of adhesion.

Next, the actual bonding method is to apply hot melt adhesive 21 (approximately 6 mg) onto the inner surface Ia of the upper half 1 placed upside down on the base 22, as shown in FIG. 3A, for example. The abrasion resistant sheet 20 is placed on top of the coating. Then, as shown in FIG. 3B, the wear-resistant sheet 20 is pressed from above for several seconds using the adhesive jig 23 to bond it. At this time, the height reference jig 24 of the adhesive jig 23 is set to the inner surface la of the upper half I.
The thickness T2 of the hot melt adhesive 21 is set to a predetermined thickness (130 μm).

At this time, as shown in the modified example of FIG. It is also possible to set the thickness T2.

Next, in FIG. 5, the spindle 10 is placed on the wear-resistant sheet 20.
hot melt adhesive 21 when pressing the tip 10a of
This is a graph showing the amount of bite of the spindle 10 relative to the amount of penetration. In this experiment, as shown in FIG. 6, the Shore A hardness of the hot melt adhesive 21 was 10,
For 20.30.52.65, the amount of bite of the spindle 10 into the hot melt adhesive 21 is measured using an electronic micrometer when the load Wl applied to the spindle 10 is sequentially changed from 150 g to 300 g. Qm is set at 150g load. As shown in FIG. 1, when the disk cassette is installed in the recording/reproducing apparatus, the load when the tip 10a of the spindle 10 is pressed against the wear-resistant sheet 20 from below is approximately 2400 g. .

As shown in the graph of FIG. 5, when the Shore A hardness of the hot melt adhesive 21 becomes 20 or less, the amount of biting becomes 250 tt m (0.25a) or more. In this case, as shown in FIG. 1, the amount by which the spindle 10 pushes up the upper half 1 in the direction of the arrow a is insufficient by 0.25+n, and the gap between the upper and lower halves 1.2 is insufficient. G becomes smaller by 0.25 mm. It has also been found that the frictional torque during the rotational drive of the disk 4 mentioned above becomes a value below the limit. In addition, the above-mentioned biting amount is 250 μm
(0.25 fl) or more, the contact area between the tip 10a of the spindle 10 and the wear-resistant sheet 20 increases,
It has been found that not only the wear-resistant sheet 20 becomes easily worn, but also the frictional resistance (rotational resistance) of the spindle 10 increases.

In addition, the high value of the Shore A hardness of the hot melt adhesive 21 is determined by the ease of adhesion of the ultra high molecular weight polyethylene sheet that is the abrasion resistant sheet 20, but if it is too high, the hardness will be affected by impact at low temperatures. Although the abrasion-resistant sheet 20 tends to peel off and the adhesion becomes less reliable, no inconvenience in use was observed when the Shore A hardness was about 65.

From the above viewpoint, the Shore A hardness of the hot melt adhesive 21 was preferably in the range of 20 to 65.

Further, since the hot melt adhesive 21 having a Shore A hardness of 20 to 65 has low fluidity, there was little sagging or leakage during adhesion of the wear-resistant sheet 20, and the adhesion work could be easily and reliably performed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various effective changes can be made based on the technical idea of the invention.

For example, the adhesive is not limited to hot melt adhesive 21.

Furthermore, the present invention is not limited to disc cartridges using micro-Frombie discs (it is applicable to various disc cartridges that record and reproduce data in various ways using sheet-like recording media).

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

The abrasion-resistant sheet can be directly attached to the inner surface of the upper half with adhesive without using double-sided adhesive tape with release paper, making it easy and quick to attach the abrasion-resistant sheet, increasing productivity. In addition, since expensive double-sided adhesive tape and release paper are not used, the cost can be reduced to about 1/8. Since the Shore A hardness of the adhesive is selected to be 20 or higher, when the tip of the spindle is pressed against the wear-resistant sheet, the amount of adhesive biting into the inside of the wear-resistant sheet can be minimized. , the upper half can be reliably pushed up depending on the spindle number, and a predetermined gap can be reliably formed between the upper and lower halves.

Since it is possible to prevent an increase in the contact area between the tip of the spindle and the wear-resistant sheet, it is possible to prevent wear of the wear-resistant sheet and improve durability, as well as increase the frictional resistance (rotational resistance) of the spindle. It can be prevented.

Adhesives have a much longer working life than double-sided adhesive tapes, resulting in significantly improved durability.

Adhesives with a Shore A hardness of 20 or more have low fluidity and cause less sagging or leakage when adhering the wear-resistant sheet, so the adhesion work can be performed easily and reliably, and quality stability can be achieved.

[Brief explanation of drawings]

1 to 6 show one embodiment of the present invention, in which FIG. 1 is an enlarged sectional view of the main part, FIG. 2 is a perspective view showing the bonding method, and FIGS. 3A to 4. The figure is a cross-sectional view showing the bonding jig.
FIG. 5 is a graph showing the amount of penetration of the spindle into the true melt adhesive, and FIG. 6 is a sectional view showing a method for measuring the amount of penetration. Fig. 7 is a sectional view showing a conventional disk cartridge, Fig. 8 is an enlarged sectional view showing the main parts of the conventional disk cartridge, Fig. 9 is a perspective view showing the conventional adhesion method, and Fig. 10 is the problem of conventional direct adhesion. It is an enlarged sectional view explaining a point. In addition, in the symbols used in the drawings, 1-1----------------Upper half 1a-
−−−−−−−−−1 inner surface 2−−−−−−−1・−−−−−1−lower half 3−−−
−−−−・−・−Cartridge 4 −−−−−−−−−
--Micro floppy disk (disc-shaped recording medium) 5-------------Center core 10--
−−1−−−−−Spindle 20−−−−−−−−−
-1 Wear-resistant sheet 21-----------
---Hot melt adhesive (adhesive).

Claims (1)

[Scope of Claims] A disk-shaped recording medium is rotatably housed in a cartridge consisting of an upper and lower half, and the tip of a spindle on which the center core of the disk-shaped recording medium is chucked is glued to the inner surface of the upper half. A disc cartridge configured to be pressed against a wear-resistant sheet, characterized in that the wear-resistant sheet is adhered to the inner surface of the upper half with an adhesive having a Shore A hardness of 20 or more.