JPH0224888A - Magnetic disk cartridge - Google Patents

Abstract

PURPOSE:To obtain a magnetic disk cartridge which is high in durability and low in error occurrence by mixing a specific amount of reinforcing powder to the magnetic layer of a magnetic disk which is rotatable inside the case of the cartridge and, at the same time, constituting the surface layer of the cleaning sheet of the cartridge which is brought into contact with and directly slid on the magnetic layer of specific fibers. CONSTITUTION:Ferromagnetic metal power of iron, etc., and 5-40wt.% of reinforcing powder of aluminum oxide are mixed into the magnetic layer of a magnetic disk housed in a cartridge case in a rotatable state and, at the same time, almost all of the surface layer of the cleaning sheet of the case on the disk side which is brought into contact with and directly slid on the magnetic layer is constituted of non-thermoplastic fibers. As a result, the durability of the magnetic disk can be improved and occurrence of errors due to the powder of thermoplastic fibers produced when the fibers wear by frictional heat can be prevented. Thus a magnetic disk cartridge which hardly produces errors can be obtained.

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. 3 [Prior Art] A magnetic disk cartridge includes a cartridge case having a magnetic head insertion port and a rotation drive opening, and
A flexible magnetic disk is housed in a rotary opening inside the cartridge case.

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

(AM to be solved by the invention) By the way, conventional cleaning sheets for magnetic disk cartridges are made of a non-woven fabric of thermoplastic fibers such as polyethylene terephthalate fibers or acrylic fibers. It was fixed to the inner surface of the cartridge case using sonic welding or adhesive.

On the other hand, for high-density recording, in recent years 1, for example, iron.

A magnetic layer containing ferromagnetic metal powder such as cobalt, cobalt-nickel, or cobalt-phosphorus is used.6 However, the ijt class magnetic layer of J3 is, for example, γ-F' e
x Since the hardness is lower compared to magnetic powder made of metal oxides such as O3, the magnetic layer is subject to severe wear due to sliding contact with the UI head.6 Therefore, reinforcing powder such as aluminum oxide is mixed in the magnetic layer. This increases the hardness of the magnetic layer.

As mentioned above, since thermoplastic fibers are used as the cleaning sheet and the magnetic layer contains hard reinforcing powder, it is likely that it will be in sliding contact with the cleaning sheet for a long period of time as the magnetic disk rotates. As a result, the thermoplastic fibers that make up the cleaning tote are softened and worn by the WI friction heat, and the generated abrasion particles adhere to the magnetic head via the magnetic disk, causing errors during recording and playback. Become.

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 for Solving the Eight Problems] In order to achieve the above-mentioned objects, the present invention provides a cartridge case made of, for example, a molded body of hard synthetic resin or a flexible sheet material, and a rotary rotor inside the cartridge case. A flexible magnetic disk that can be stored in
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 coverage is regulated within the range of 5 to 40% by weight. , 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 non-thermoplastic fibers such as rayon fibers.

[Embodiments of the invention] Next, examples of the present invention will be described.

In the present invention, examples of the thermoplastic synthetic resin used for the cartridge case include 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 polyester or polyimide, for example, and coated with a magnetic layer on one or both sides, and has a certain degree of flexibility.

11A to 6 are for explaining a magnetic disk cartridge according to an embodiment of the present invention, and FIG. 1 is an exploded perspective view of the disk cartridge.

Figure 2 is a bottom view showing the cleaning sheet attached to the upper case, Figure 3 is a plan view showing the cleaning sheet being attached to the lower case, and Figure 4 is the usage state of this magnetic disk cartridge. 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 l is composed of an upper case la and a lower case tb, 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 la. Near the front surfaces of the upper case la and the lower case tb, as shown in FIG. The magnetic head insertion port 5 is opened at .

As shown in FIG. 3, four counterbore-shaped portions 7.7 are formed on the inner surface of the upper case la and on both left and right sides of the magnetic head insertion opening 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 width W3 of the recess 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 la, and two of the protrusions 8 on both sides are slightly wider 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 la, 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 la. As mentioned above, since the fourth part 7 of the upper case la has sufficient width, the fourth part 7
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 ib and at a position substantially opposite to the protrusion 8 of the upper case la. ing. As shown in FIGS. 3 and 5, the base 1 of the elastic piece 15 is formed by bending a plastic sheet.
6 is fixed to the inner surface of the lower case 1b in the vicinity of the support portion 13 by an appropriate semi-immersion method such as adhesive or heat fusion. The free end F of the elastic piece 15 is supported by the support portion 13 to maintain its inclined state.

A regulating rib 9 is also provided protruding from the inner surface of the lower case 1b.

A cleaning sheet 10 is arranged inside it. 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. As shown in FIG. 3, the elastic piece 15 is covered by placing the cleaning sheet IO inside the lower case lb.

The peripheral part of the cleaning sheet IO is ultrasonically welded 12 to the lower case lb, but the vicinity of the first elastic piece 15 is ultrasonically welded fi.
12 is omitted.

When a magnetic disk cartridge is assembled by combining the upper case la and the lower case lb, 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 it up a little.

Cleaning sheet 10.1 with magnetic disk 2 on top and bottom
It is elastically clamped by 0. and magnetic disk 2
As the disc rotates, the cleaning sheet 10 performs tfIm on the disc surface.

41st! ! 1 is a diagram showing the usage status of a magnetic disk cartridge, and 18 in FIG. 1 is a magnetic head.

The cleaning sheet 1O has three 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
A case side nonwoven fabric layer 20 facing the disc side nonwoven fabric layer 20 and an intermediate nonwoven fabric layer 21 for connecting the disk side nonwoven fabric layer 19 and the case side nonwoven fabric layer 20 are provided.

The disc-side nonwoven fabric layer 19 and the case-side nonwoven fabric layer 20 are both made of rayon fiber alone, and are made so that there is no distinction between the front side and the back side. As the rayon fiber, viscose rayon, copper ammonia rayon, acetate rayon, etc. are used. The tensile strength of rayon fiber (stable) is approximately 2.5 to 3.1 g/D
, elongation rate is approximately 16-22%, elongation elastic modulus (at 3% elongation)
is about 55-80%, and the specific gravity is about 1.50-1.52.

The intermediate nonwoven fabric layer 21 is composed of a mixed fiber layer of rayon fibers and polyamide fibers. The mixing ratio of rayon fiber and polyamide fiber (rayon/polyamide) is approximately 1
/9 to 9/1, particularly 37
A range of 7 to 7/3 is suitable.

Polyamide fiber is a fiber whose raw material monomer is a polycondensate of adipic acid and hexamethylene diamine. The tensile strength of polyamide fibers is approximately 4.5 to 7.5. The elongated skewer is approximately 25 to 60%, and the elongation modulus (at 3% elongation) is approximately 95 to 1.
00%, and the specific gravity is approximately 1.14.

The cleaning sheet IO can be made of rayon fiber alone, but as in this embodiment, an intermediate nonwoven fabric layer 21 made of a nonwoven fabric containing thermoplastic fibers is provided between the disk side nonwoven fabric layer 19 and the case side nonwoven fabric layer 20. By providing this, it is possible to achieve good thermal fusion with the cartridge case 1.

The intermediate nonwoven fabric layer 21 is made of a mixture of rayon fibers and polyamide fibers as described above, as well as other materials such as polyethylene terephthalate, bolier, tyrene, polypropylene, polystyrene, and polyvinyl chloride.

Various thermoplastic fibers such as acrylic resin can be suitably used. In particular, since rayon fibers are used in the disc side nonwoven fabric layer 19 and the case side nonwoven fabric layer 20 as mentioned above, in consideration of compatibility with these two layers 19 and 20, the intermediate nonwoven fabric layer 21 contains rayon fibers. It is preferable to use a layer of mixed fibers.

The basis weight of this cleaning sheet IO is not particularly limited, but is suitably about 20 to 50 g/rrl'. The basis weight here refers to the weight of five 50 x 50 cm samples.

This is the average value of those values.

The cleaning sheet lO has a thickness of 150 to 300μ.
m is appropriate. Cleaning sheet 10 according to the example
The specific physical properties of are as follows.

As mentioned above, the cleaning sheet 1O has a three-layer structure, but when actually assembling a magnetic disk suite using this cleaning sheet 1O, there are cases where all of the fibers in sliding contact with the magnetic disk 2 are not carrayon fibers, and the intermediate A very small portion of the thermoplastic fibers (polyamide fibers) in the nonwoven fabric layer 21 may come out onto the surface side of the cleaning sheet 10 and come into contact with the magnetic disk 2 due to the entanglement of the WaS. However, even in such a case, the ratio of the thermoplastic fibers making sliding contact with the magnetic disk 2 is about 10
% or less, and substantially 100% of the fibers that come into contact with the magnetic disk 2 are rayon fibers.

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

Examples of the ferromagnetic metal powder include iron, copal 1-. Cobalt-nickel, cobalt-phosphorus, etc. are used, and in this example, an example using iron powder is shown.

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

Kuro l1. Silicon carbide, silicon nitride, etc. are used.

In this embodiment, an example using 1-hyaluminum acid is shown. 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.

Table 3 Table 2 The reinforcing powder is, for example, aluminum oxide, and the magnetic properties of this magnetic disk are as shown in Table 4 below.

Table 4 Next, the hardening effect in the magnetic layer (aluminum oxide: particle size 0.4
Table 5 below shows the results of examining the relationship between the content (up to 0.5 ttm) and the material of the cleaning sheet.
.

Note that 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. Mixed paper 1 indicates a mixed paper of rayon (50%) and polyethylene terephthalate 1- (50%). Mixed paper 2 shows a mixed paper of rayon (50%) and acrylic (50%). Mixed paper 3 is made of rayon (50%) and polyamide (50%)
) is shown.

Acceleration durability: head load 140 g, circumferential speed 30 m/se
This is the durability when tested under the conditions of e.

The error occurrence indicates the occurrence of an error in 24-hour seek.

As is clear from Table 5, when the content of reinforcing material (aluminum oxide) in the magnetic layer is small, for example, 1 to 3% by weight, because relatively soft metal magnetic powder is used, The durability of the magnetic disk is insufficient, whereas the content of reinforcing powder in the magnetic layer is 5% by weight or more,
Preferably, when the amount is 10% or more, the durability of the magnetic disk is significantly improved.

On the other hand 1. If the content of Ura strong powder increases, the content of other components such as metal magnetic powder and binder will inevitably be limited, making it difficult to obtain the desired characteristics. The upper limit of the reinforcing powder must be kept at 40 #1% by weight, and the preferred reinforcing powder content is $110 to 30% by weight.

By regulating the content of the reinforcing powder within the range of 5 to 40%, it is possible to improve the durability of the magnetic disk. However, the constituent fibers of the cleaning sheet were polyethylene terephthalate fiber alone (Comparative Examples 5 to 11), a mixture of rayon fiber and polyethylene terephthalate fiber (Comparative Example 12), and a mixture of rayon fiber and acrylic fiber (Comparative (N13)). In addition, heat-treated paper such as mixed paper of rayon fiber and polyamide fiber (Comparative Example 14)
When plastic fibers are contained, the thermoplastic fibers are worn out by frictional heat with the magnetic disk, and errors may occur due to the abrasion powder.

On the other hand, in Examples 1 to 7 of the present invention, the magnetic disks have excellent durability and do not cause errors. It has been confirmed through experiments that such an effect can be similarly exhibited even when using 5ike no ura flour.

Next, the relationship between the surface roughness of the magnetic disk and the wear of the cleaning sheet will be explained. To minimize wear on the cleaning sheet.

It is also necessary to consider the surface roughness of the magnetic disk.

As in the past, the surface roughness of the magnetic disk was 1, for example 0.0.
If it is relatively coarse, such as 20-0.025 μm.

Inevitably, the cleaning sheet tends to wear out.

On the other hand, the surface roughness Ra of the magnetic disk was set to 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.

Note that the surface roughness of the magnetic layer is 2 μm, about the same as that of a stylus.

Stylus #j car 25mg, cutoff 0.08mm
Measurements were made using a stylus second surface rf1sl meter under conditions of a scanning speed of 0.03 mm/sec. In addition, the surface roughness of the magnetic layer can be determined by adjusting its surface treatment conditions (temperature, pressure, and number of stages of the calender roll in the calendering processing device).
By doing so, the desired surface roughness can be maintained.

As shown in Table 3 above, when a urethane resin or one binder is contained in the magnetic layer, abrasion powder is generated from the cellulose yarn fibers of the magnetic layer.
Because there is no affinity for magnetic disks, there is no abrasion powder on the magnetic disk. There is less wear and tear, which can help prevent errors from occurring.

In the actual JIM example described above, rayon m fabric was used as the Jl'-hot fiber, but the present invention is not limited thereto, and other cellulose yarns such as cotton fiber may be used. Similar effects can be obtained using fibers.

t#4 light effect J The present invention has been described above and has an independent configuration.

The magnetic device has excellent durability and is error-free and reliable.

4. A small explanatory diagram of fI#l of turning is shown in 4 according to the embodiment of the present invention! This is to explain the magnetic disk cartridge; Fig. 1 is an exploded perspective view of the magnetic disk cartridge, and Fig. 2 is an exploded perspective view of the magnetic disk cartridge. U is a bottom view showing the state in which the cleaning sheet is attached to the upper case, FIG. 3 is a top view showing the state in which the cleaning sheet is attached to the lower case, and FIG. 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.

l...Cartridge case.

la... Upper case, lb...
lower case.

2...magnetic disk, f disk.

0...Cleaning sheet.

2... Ultrasonic welding.

9... Disk side nonwoven fabric.

0...Case side nonwoven fabric.

l...Intermediate nonwoven fabric.

Claims (1)

[Claims] (1) A magnetic disk cartridge comprising a cartridge case, a magnetic disk rotatably housed within the cartridge case, and a cleaning sheet supported on the inner surface of the cartridge case. The magnetic disk has a magnetic layer containing ferromagnetic metal powder and reinforcing powder whose content is regulated in a range of 5 to 40% by weight, and the disk is in direct sliding contact with at least the magnetic layer of the cleaning sheet. A magnetic disk cartridge characterized in that almost all of the side surface layer is composed of non-thermoplastic fibers. (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)
), wherein the non-thermoplastic fiber is rayon. (5), claim (1), claim (2) or claim (3)
2.) The magnetic disk cartridge according to claim 1, wherein the cleaning sheet is composed of three layers, the front layer and the back layer being made of rayon fiber alone, and the middle layer being made of a mixture of rayon fiber and thermoplastic fiber. (6), Claim (1), Claim (2), Claim (3), Claim (4)
) or the magnetic disk cartridge according to claim (5), wherein the magnetic disk has a surface roughness (Ra) of 0.01 μm or less. (7), Claim (1), Claim (2), Claim (3),
Or a magnetic disk cartridge according to claim 4, wherein the magnetic layer contains urethane resin as a binder.