JPH043379A - Floppy disk - Google Patents

Abstract

PURPOSE:To obtain a floppy disk superior in weather resistance by joining a flexible magnetic disk and a center core not at a normal temperature but at a high temperature in a proof circumstance range. CONSTITUTION:A 25% ketone solution of an adhesive 3 essentially consisting of a nitrile rubber is dropped to the outside edge of a center code 2, which is preheated to 60 deg.C on a hot plate 1 whose surface temperature is kept at about 60 deg.C, in an annular form having about 1mm width and about 0.1mm thickness, and a flexible magnetic disk 4 where a magnetic coating film is formed on both faces of a doughnut polyester film having 33mum thickness is adhered with 1kg/cm<2> pressure for 0.5 seconds by a pressing jig 5 held at about 60 deg.C to obtain a magnetic disk with core, and it is stored in a hard case to produce a small-sized floppy disk. The temperature range is 45 to 115 deg.C and is preferably 55 to 85 deg.C, and at least 100g/cm<2> pressure is necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a floppy disk in which a cored magnetic disk consisting of a flexible magnetic disk and a center core is rotatably housed in a hard case made of hard plastic or the like. It is inserted between the discs.

Conventional technology Small floppy disks of 3.5 inches or less have a high recording density, so it is necessary to increase the accuracy of chucking.
It uses a center core. For this purpose, the annular portion along the inner edge of the flexible magnetic disk and the annular portion along the outer edge of the center core are bonded together.

The most common method of bonding has been to bond at room temperature using a sheet coated with or impregnated with an adhesive, or an adhesive ring made by punching out a ring-shaped sheet of the adhesive itself.

Problems to be Solved by the Invention A floppy disk is chunked by a center core, and data is recorded concentrically on a flexible magnetic disk. At the adhesive part between the center core and the magnetic disk,
If this occurs, the recorded concentric data will be eccentric and will be partially off-trunk. This amount of eccentricity, that is, the "misalignment" of the bonded portion, deteriorates the modulation and eventually makes it impossible to read the data, so it must be suppressed as much as possible.

However, when bonding a flexible magnetic disk and a center core using the above-mentioned method, the thermal/humidity expansion coefficients and residual thermal strain of these components are slightly different, so it is difficult to bond the flexible magnetic disk and the center core in various temperature/humidity environments such as in weather resistance tests. It was occasionally observed that "slippage" occurred at the adhesive part when the adhesive was removed.

The present invention is intended to solve these problems, and aims to provide a floppy disk using a method in which the above-mentioned "misalignment" is less likely to occur.

Means for Solving the Problems In order to solve the above-mentioned problems, we carefully observed the relationship between the method of bonding the flexible magnetic disk and the center core and the state in which "slippage" occurs.

As a result, we found that a method of bonding the center core and the flexible magnetic disk under pressure at least at the maximum temperature within the guaranteed environmental range is extremely effective.

That is, to give an example of a method of bonding a magnetic disk and a center core suitable for the floppy disk of the present invention, a center core heated to at least the maximum temperature within the guaranteed environment range and an annular portion (flange) along the outer edge of the center core are bonded together. ), a magnetic disk with a core was press-bonded to a donut-shaped flexible magnetic disk using a pressing jig heated to at least the maximum temperature within the guaranteed environment range, and the cored magnetic disk was rotatably housed in a hard case. It is something.

The above temperature range is 45-115"C2, preferably 55-85"C2, and the pressure is at least 100"C2.
g/chill.

Temperatures below 45° C. will not cover the guaranteed range, and temperatures that are too high may cause deterioration of the magnetic layer or deformation of the heath film, which is not preferable.

Examples of the above adhesive include nitrile rubber.

There are various types such as chloroprene rubber type and others.

Note that the above bonding method is an example of the present invention, and it is important that the heat and pressure described above be applied at the bonded portion.
Various methods can be considered.

Function: When the adhesive part between the flexible magnetic disk and the center core receives heat exceeding the maximum temperature within the guaranteed environment range, distortion, etc. is removed, so even if it is subjected to environmental changes such as weather resistance tests, no unbalanced force will be applied. Therefore, the occurrence of "slippage" at the adhesive part is suppressed, and a floppy disk with excellent weather resistance can be obtained.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG. As shown in the figure, first apply a 25% ketone solution (viscosity: 35 poise) at a convergence of approximately 1m
Dropped in an annular shape with a thickness of about 0.2 am, and then a drop with a thickness of 33 μm.
A flexible magnetic disk 4 with a magnetic coating film formed on both sides of a donut-shaped polyester film of M is bonded under pressure at 1 kg/cd for 0.5 seconds using a pressing jig 5 kept at about 60°C, and a core is attached. As a magnetic disk, this was stored in a hard case to create a small floppy disk.

This small floppy disk is JIS, X6223
A weather test was conducted based on the conditions described in , and the average modulation of all tracks was compared. The results are shown in Table 1.

Comparative Example Assembly and testing were carried out in the same manner as in the example except that the hot plate, center core, and pressing jig were not heated and were kept at room temperature.The results are shown in Table 1.

Looking at the results in Table 1, the modulation values before the test are not much different between the example and the comparative example, but after the weather resistance test, the example shows little change and is stable, while the comparative example shows a large change. You can see that it is happening. This indicates that in the example, the above-mentioned "slippage" at the bonded portion was suppressed.

(Margins below) Table 1 Unit: 2% Number of samples - 10 Effects of the Invention As is clear from the above embodiments, according to the present invention, when joining a flexible magnetic disk and a center core, it is possible to bond the flexible magnetic disk and the center core at a guaranteed temperature, rather than at room temperature. By performing bonding in the high temperature range of the environmental range, stable adhesion is achieved that does not shift even under changes in temperature and humidity environments, and a floppy disk with excellent weather resistance can be provided.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a bonding method according to an embodiment of the present invention. ■・・・Hot plate, 2・・・Center core, 3・・・Adhesive, -4・・・Flexible magnetic disk, 5・・・Press jig. 3-Tsubaki Care (-~Flexi 7) Shifuni No. J〆7z Fu 5---↑Ko Manj Addition

Claims (2)

[Claims] (1) A donut-shaped flexible magnetic disk,
A magnetic disk with a core is rotatably housed in a hard case, the magnetic disk having a core attached to the center core with an adhesive and pressurized while the bonded portion is heated to at least the highest temperature within the guaranteed temperature range. floppy disk. (2) The above adhesive part is 45-115℃, preferably 55℃
The floppy disk according to claim 1, wherein the floppy disk is pressurized to 100 g/cm^2 or more at ~85°C.