JPH02141984A - Magnetic disk cartridge - Google Patents

Abstract

PURPOSE:To improve durability and to suppress an error by setting the content rate of a reinforcing powder in a magnetic disk within a specific range, and setting the disk side surface layer of a cleaning sheet to a specific fiber. CONSTITUTION:A cleaning sheet 10 is equipped with a disk side nonwoven fabric layer placed opposite to a magnetic disk 2 and a case side nonwoven fabric layer placed opposite to a cartridge case 1. The disk side nonwoven fabric layer is composed simply of a polyamide fiber. For the case side nonwoven fabric layer, it is appropriate to use a mixed fiber composed of polyamide and rayon in consideration of the thermal welding characteristic between the case side nonwoven fabric layer and the case 1. For the magnetic layer of a disk 7, the content rate of the reinforcing powder of oxidized aluminum, etc., is set to 5-40 weight %. Thus, the abrasion of the cleaning sheet can be suppressed, and the durability of the disk can be also made into satisfactory one by using the polyamide fiber for the disk side of the cleaning sheet and setting the content rate of the reinforcing powder in the magnetic layer of the disk to 5-40 weight %.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic disk cartridge in which a magnetic disk is rotatably housed in a cartridge case molded of hard synthetic resin or a flexible cartridge case. In particular, it relates to its magnetic layer and the cleaning sheet that is in sliding contact with it.

[Prior Art] A magnetic disk cartridge includes a cartridge case having a magnetic head insertion slot, a rotation drive opening, etc.
A flexible magnetic disk rotatably housed inside the cartridge case.

The cleaning sheet is supported on the inner surface of the cartridge case.

[Problem to be solved by the invention]

By the way, conventional cleaning sheets for magnetic disk cartridges are made of polyethylene terephthalate fiber, for example.
Alternatively, the cleaning sheet is made of a nonwoven fabric of thermoplastic fibers such as acrylic fibers, and this cleaning sheet is fixed to the inner surface of the cartridge case by, for example, ultrasonic welding or adhesive.

On the other hand, for high-density recording, in recent years, for example, iron.

A magnetic layer containing ferromagnetic metal powder such as cobalt, cobalt-nickel, and cobalt-phosphorus is used. However, these metal magnetic powders are, for example, γ-F ez O3
Because the hardness is lower than magnetic powder made of metal oxides such as The hardness of the layer is increased.

Since the above-mentioned fibers are used as the cleaning sheet and the magnetic layer contains hard reinforcing powder, the rotation of the magnetic disk causes it to come into sliding contact with the cleaning sheet for a long period of time. The aforementioned fibers that make up the tote wear out, and the generated abrasion particles adhere to the magnetic head via the magnetic disk.
This may cause errors during recording or playback.

The purpose of the present invention is to eliminate such drawbacks of the prior art,
To provide a magnetic disk cartridge with excellent durability and less error.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention comprises: (1) a cartridge case made of, for example, a molded body of hard synthetic resin or a flexible sheet material; and a flexible magnetic disk rotatably housed within the cartridge case. ,
The present invention is directed to a magnetic disk cartridge including a cleaning sheet supported on the inner surface of the cartridge case.

In the present invention, the magnetic disk has a magnetic layer containing ferromagnetic metal powder, such as iron, and reinforcing powder, such as aluminum oxide, whose content is regulated in the range of 5 to 40% by weight, The cleaning sheet is characterized in that almost all of the surface layer on the disk side, which is in direct sliding contact with the magnetic layer, is made of polyamide fibers.

[Embodiments of the invention]

Next, examples of the present invention will be described.

The thermoplastic synthetic resin used for the cartridge case in the present invention includes, for example, ABS resin.

Polyacetal resin, polystyrene resin, etc. are used, and a cartridge case of a desired shape is formed by injection molding.

The magnetic disk housed in the cartridge case is made of a base film made of, for example, polyester or polyimide, with a magnetic layer coated on one or both sides, and has appropriate flexibility.

1 to 6 are for explaining a magnetic disk cartridge according to an embodiment of the present invention.

Figure 1 is an exploded perspective view of the disk cartridge, Figure 2 is an exploded perspective view of the disk cartridge.
The figure is a bottom view showing the cleaning sheet attached to the upper case, Figure 3 is a plan view showing the cleaning sheet attached to the lower case, and Figure 4 is the magnetic disk cartridge showing how it is used. FIG. 5 is an enlarged sectional view of the vicinity of the head insertion port, FIG. 5 is an enlarged sectional view of the vicinity of the elastic piece of this magnetic disk cartridge, and FIG. 6 is an enlarged sectional view of the cleaning sheet.

The magnetic disk cartridge includes a cartridge case 1, a magnetic disk 2 rotatably housed in the cartridge case 1, and a shutter 3 slidably supported by the cartridge case 1.
It is mainly composed of.

The cartridge case 1 is composed of an upper case 1a and a lower case 1b, which are injection molded from a hard synthetic resin such as ABS resin.

Approximately in the center of the lower case 1b is an opening 4 for inserting the rotational drive shaft.
is formed, and a rectangular head insertion opening 5 is provided near it, and a head insertion opening 5 is similarly provided in the upper case 1a. Near the front surfaces of the upper case 1a and the lower case lb, as shown in FIG. The magnetic head insertion port 5 is opened at .

As shown in FIG. 3, counterbore-shaped recesses 7.7 are formed on the inner surface of the upper case 1a and on both left and right sides of the magnetic head insertion port 5, respectively. The vertical width W1 of the recess 7 is approximately equal to the width W2 in the longitudinal direction of the magnetic head insertion port 5, and the horizontal width W3 of the four portions 7 is the width (width) in the direction perpendicular to the longitudinal direction of the magnetic head insertion port 5. It is restricted to 0.3 times or more of W4, preferably in the range of 0.5 to 1.5 times.

A large number of linearly extending protrusions 8 are provided on the upstream side of the magnetic head insertion slot 5 in the disk rotation direction in the upper case 1a, and two of the protrusions 8 on both sides are slightly higher than the protrusions 8 on the inner side.

An arcuate regulating rib 9 for regulating the storage position of the magnetic disk 2 is protruded from the inner surface of the upper case 1a, a part of which passes through the end of the recess 7, and the regulating rib 9 is connected to the reinforcing body around the recess 7. It is also useful.

A C-shaped cleaning sheet 10 is inserted inside the regulating rib 9. The width W5 of the opening 11 provided in the cleaning sheet 10 at a position corresponding to the magnetic head insertion opening 5 is designed to be slightly larger than the width W4 of the magnetic head insertion opening 5. By placing the cleaning sheet IO on the inner surface of the upper case 1a, the recess 7 and the protrusion 8 are also covered, and the peripheral portion of the cleaning sheet 10 is ultrasonically welded to the upper case 1a. As mentioned above, since the recess 7 of the upper case 1a has a sufficient width, the fourth
As shown in the figure, an opening 11 in the cleaning sheet 10
The edges can be ultrasonically welded 12 in the recess 7.

As shown in FIGS. 3 and 5, a protruding support portion 13 and a protruding strip 14 for preventing sticking are provided on the inner surface of the lower case 1b at a position substantially facing the protrusion 8 of the upper case la. There is. As shown in FIGS. 3 and 5, the base 1 of the elastic piece 15 is formed by bending a plastic sheet.
6 is the inner surface of the lower case 1b and is fixed to the vicinity of the support portion 13 by appropriate means such as adhesive or heat fusion.The free end 17 of the elastic piece 15 is supported by the support portion 13 and is in an inclined state. is retained.

A regulating rib 9 is also provided protruding from the inner surface of the lower case 1b, and a cleaning sheet 10 is disposed inside the regulating rib 9. The width W5 of the opening 11 provided in the cleaning sheet 10 at a position corresponding to the magnetic head insertion opening 5 is designed to be slightly larger than the width W4 of the magnetic head insertion opening 5. Third
As shown in the figure, insert the cleaning sheet 10 into the lower case 1b.
By placing it inside the elastic piece 15, the elastic piece 15 is covered, and the peripheral part of the cleaning sheet 1O is ultrasonically welded 12 to the lower case 1b, but the ultrasonic welding 12 is omitted in the vicinity of the elastic piece 15. There is.

When a magnetic disk cartridge is assembled by combining the upper case 1a and the lower case 1b, the cleaning sheet 10 is partially lifted from the lower case 1b by the elastic piece 15 as shown in FIG. The raised protrusion 8 pushes up the magnetic disk 2 elastically between the upper and lower cleaning sheets 10 and 10. As the magnetic disk 2 rotates, the disk surface is cleaned by the cleaning sheet 10.

FIG. 4 is a diagram showing the state in which the magnetic disk cartridge is used, and numeral 18 in FIG. 1 is a magnetic head.

The cleaning sheet 10 has two parts as shown in FIG.
It has a layered structure. That is, the disk-side nonwoven fabric layer 19 facing the magnetic disk 2 and the cartridge case 1
and a case-side nonwoven fabric layer 20 facing each other.

The disc-side nonwoven fabric layer 19 is composed of polyamide fibers alone, and the fibers include, for example, 6
Low nylon, 6-nylon.

Aliphatic polyamides such as 64-nylon, aromatic polyamides having an aromatic ring structure in the main chain, such as those obtained by condensation polymerization of m-phenyl diamine and isophthalic acid chloride, or bis p-amine cyclohexyl Alicyclic polyamide obtained by polycondensation of methane and dodecanedioic acid (Cxz) is used. The aliphatic polyamide fiber (stable) made from a polycondensate of adipic acid and hexamethylene diamine as a raw material monomer has a tensile strength of about 4.5 to 7.5, an elongation rate of about 25 to 60%, and an elongation. Elastic modulus (at 3% elongation) is approximately 95-100%, specific gravity is approximately 1
．． It is 14.

The case-side nonwoven fabric layer 20 is composed of a mixed fiber layer of rayon fibers and polyamide fibers.

Mixing ratio of rayon fiber and polyamide fiber (rayon/
Polyamide) is suitably selected in the range of about 1/9 to 9/1, particularly preferably in the range of 7/3 to 515. The tensile strength of rayon fiber (stable) is about 2.5 to 3.
1g/D, elongation rate is approximately 16-22%, elongation modulus (3%
When stretched) is approximately 55-80%, specific gravity is approximately 1.50-1.5
It is 2.

Although the cleaning sheet 10 can be made of polyamide fiber alone, by providing the disk side nonwoven fabric layer 19 and the case side nonwoven fabric layer 20 as in this embodiment,
It can be thermally bonded well to the cartridge case 1.

Further, as shown in FIG. 7, an intermediate nonwoven fabric layer 21 may be provided between the disk side indestructible fabric 19 and the case side nonwoven fabric layer 20. By providing the intermediate nonwoven fabric layer 21 in this way, it is possible to cope with cutting properties during processing and changes in elongation due to temperature and humidity.

For this intermediate nonwoven fabric layer 21, in addition to a mixture of rayon fibers and polyamide fibers, various thermoplastic fibers such as polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, and acrylic resin can be used.

The basis weight of this cleaning sheet 10 is not particularly limited, but is suitably about 20 to 50 g/rrr. Note that the basis weight here is a value obtained by measuring the weight of five 50×50 cm samples and taking the average value thereof.

The thickness of the cleaning sheet 10 is 150 to 300 μm
is appropriate. The specific physical properties of the cleaning sheet 10 according to the example are as follows.

As mentioned above, the cleaning sheet 1o has a two-layer structure, but when a magnetic disk suite is actually assembled using this cleaning sheet 10, all of the fibers that come into sliding contact with the magnetic disk 2 may not be polyamide fibers, and the case A very small portion of the rayon fibers in the side nonwoven fabric layer 20 are intertwined with each other to form the cleaning sheet 1.
0 and may come into contact with the magnetic disk 2.

However, even in such a case, the proportion of polyamide fibers that come into sliding contact with the magnetic disk 2 is approximately 10% or less, and substantially 100% of the fibers are in contact with the magnetic disk 2.
is polyamide fiber.

Next, the composition of the magnetic layer will be explained.

Examples of ferromagnetic metal powder include iron, cobalt, and cobalt.
Nickel, cobalt phosphorus, etc. are used, and this example shows an example using iron powder.

The physical properties of the iron powder used in the examples are shown in Table 2 below.

Table 2 Table 3 Examples of reinforcing powders include aluminum oxide, chromium,
Silicon carbide, silicon nitride, etc. are used, and this example shows an example using aluminum oxide. The particle size of the reinforcing powder is 0.4 to 0.5 μm.

The preferred composition ratio of the magnetic layer is shown in Table 3 below.

The magnetic properties of this magnetic disk are shown in Table 4 below.

Table 4 Next, reinforcing powder in the magnetic layer (aluminum oxide, particle size 0.4
Table 5 below shows the results of a study on the relationship between the content (up to 0.5 μm) and the material of the cleaning sheet.

Table 5 The constituent fibers in the table refer to the constituent fibers of the surface layer of the cleaning sheet that comes into sliding contact with the magnetic disk. P.E.
T represents polyethylene terephthalate, and PP represents polypropylene.

Acceleration durability is the degree of abrasion when tested for 24 hours under the conditions of a head load of 40g and a circumferential speed of 30 rn/sec, and the evaluation is divided into 5 grades from 1 to 5, with 1 being the worst and increasing the number. 5 is the best rating. Scratch A indicates a scratch on the disk, and scratch B indicates a scratch on the cleaning sheet. Further, the number of error sheets indicates the number of sheets in which errors occur during 24-hour seek using 10 samples each.

As is clear from Table 5, the magnetic disk of Example 1 of the present invention has excellent durability and no errors occur.

If the content of the reinforcing powder (aluminum oxide) in the magnetic layer is low, for example 1 to 3% by weight, the magnetic disk will not have sufficient durability because the metal magnetic powder used is relatively soft. On the other hand, when the content of reinforcing powder in the magnetic layer is 5% by weight or more, preferably 10% by weight or more, the durability of the magnetic disk is significantly improved.

On the other hand, if the content of reinforcing powder becomes too large, the content of other components such as metal magnetic powder and binder will inevitably be limited, making it impossible to obtain desired properties.

Therefore, the upper limit of the reinforcing powder content must be kept at 40% by weight, and the preferred reinforcing powder content is 10 to 30% by weight. By regulating the content of reinforcing powder within the range of 5 to 40% by weight in this way, the durability of the magnetic disk can be improved.

Next, the relationship between the surface roughness of the magnetic disk and the wear of the cleaning sheet will be explained. In order to reduce the wear of the cleaning sheet as much as possible, it is necessary to consider the surface roughness of the magnetic disk.

Conventionally, the surface roughness of a magnetic disk is, for example, 0.0.
If the thickness is relatively rough, such as from 20 to 0.025 μm, the cleaning sheet is inevitably prone to wear.

On the other hand, the surface roughness Ra of the magnetic disk is 0.01μ
It has been found that wear of the cleaning sheet can be minimized over a long period of time by setting the thickness to less than m, preferably less than 0.005 μm.

The surface roughness of the magnetic layer was as follows: stylus diameter 2 μm, stylus load 25 mg, cutoff 0.08 mm, and scanning speed 0.0.
Measurement was performed using a stylus type surface roughness meter under the condition of 3 mm/sec. Furthermore, the surface roughness of the magnetic layer can be maintained at a desired level by changing its surface treatment conditions (temperature, pressure, and number of stages of calender rolls in a calendering device).

〔Effect of the invention〕

This is because the present invention has the configuration described above.

It is possible to provide a highly reliable magnetic disk cartridge with excellent magnetic disk durability and no error occurrence.

[Brief explanation of the drawing]

The figures are all for explaining a magnetic disk cartridge according to an embodiment of the present invention, and FIG. 1 is an exploded perspective view of the magnetic disk cartridge, and FIG. 2 shows a state in which a cleaning sheet is attached to the upper case. The bottom view, Figure 3 is a plan view showing the cleaning sheet attached to the lower case, Figure 4 is an enlarged sectional view of the vicinity of the magnetic head insertion slot showing how this magnetic disk cartridge is used, and Figure 5 is this. FIG. 6 is an enlarged sectional view of the vicinity of the elastic piece of the magnetic disk cartridge, FIG. 6 is an enlarged sectional view of the cleaning sheet, and FIG. 7 is an enlarged sectional view showing a modified example of the cleaning sheet. 1...Cartridge case, 1a...Upper case, 1b...Lower case, 2...Magnetic disk, 0...Cleaning sheet, 2... Ultrasonic welding, 9... Disk side nonwoven fabric layer, 0... Case side nonwoven fabric layer, 1... Intermediate nonwoven fabric layer. Figure 2, Figure 4, B, Figure 3, Figure t. Diagram

Claims (6)

[Claims] (1) A magnetic disk cartridge comprising a cartridge case, a magnetic disk rotatably housed in the cartridge case, and a cleaning sheet supported on an inner surface of the cartridge case, wherein the magnetic disk is made of a ferromagnetic metal. The cleaning sheet has a magnetic layer containing reinforcing powder whose content is regulated in the range of 5 to 40% by weight, and almost all of the surface layer on the disk side that is in direct sliding contact with at least the magnetic layer of the cleaning sheet is made of polyamide fibers. A magnetic disk cartridge comprising: (2) A magnetic disk cartridge according to claim (1), wherein the ferromagnetic metal powder is iron. (3) A magnetic disk cartridge according to claim (1) or claim (2), wherein the reinforcing powder is aluminum oxide. (4), claim (1), claim (2) or claim (3)
3.) The magnetic disk cartridge according to claim 1, wherein the cleaning sheet is composed of two layers, the surface layer of which is made of polyamide fiber alone, and the back layer of which is made of a mixture of rayon fiber and thermoplastic fiber. (5), claim (1), claim (2) or claim (3)
), the surface roughness (Ra) of the magnetic disk
1. A magnetic disk cartridge characterized in that the diameter is 0.01 μm or less. (6), claim (1), claim (2) or claim (3)
), wherein the magnetic layer contains a urethane resin as a binder.