JP2003162876A - Magnetic disk cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized and low-priced magnetic disk cartridge having a large record capacity that can perform easy centering in the chucking structure of the cartridge and eliminate prying when attaching and detaching the cartridge. <P>SOLUTION: A circular disk-like magnetic disk 14 is rotably arranged in the housing 10 of a magnetic disk cartridge 8. A center core 18 including the projection part of an extremely small truncated core magnetic substance is installed coaxially with a magnetic disk 14 at the center part of the magnetic disk 14. On the other hand, a bearing part 24 bearing the center core 18 complementary to the center core 18 is formed coaxially with a spindle 22 at the top end of the spindle rotation-driven by a motor. A permanent magnet 30 magnetically absorbing the center core 18 when chucking is arranged at the hollow 32 of the bottom part of this bearing part 24. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is replaceable with a card-type disk drive that can be loaded into a card slot of an electronic device such as a digital still camera, a digital video camera, or a laptop computer. The present invention relates to a small magnetic disk cartridge that can be loaded. 2. Description of the Related Art Conventionally, various recording media are removably loaded in a card slot of an electronic device such as a digital still camera, a digital video camera, a notebook personal computer, and the like for recording and reproduction. . As such a recording medium, a semiconductor memory type, a hard disk type, an optical disk type, a small magnetic disk such as a floppy (registered trademark) disk, etc.
Various things are in practical use. Among them, the semiconductor memory is easy to handle and the recording capacity is suitably large, so it is the most popular but relatively expensive. Therefore, in a digital camera or the like using these memories, it is common to transfer the captured image data to a personal computer or the like, and then delete the data and use the recording medium repeatedly. As a hard disk type, 340
Those having a capacity of MB or 1 GB are known, but this is also expensive, and the data is transferred and stored elsewhere, and the recording medium is repeatedly used. The optical disk type has a large recording capacity for its size. For example, 256 MB of data can be recorded in a size of 35 mm × 41 mm × 11 mm.
A device with a recording capacity of 512 MB is also being realized. However, since the optical disk takes time to write, there is a drawback that the recording speed is slow. On the other hand, a magnetic disk such as a floppy (registered trademark) disk can be made as small as about 50 mm × 55 mm × 2 mm and can be exchanged into a disk drive of a size that can be inserted into a card slot of a personal computer or the like. Is also known, but this has a capacity of 40
It's as small as MB, and it has insufficient capacity in terms of recording camera images, and its size is not suitable for digital cameras. In recent years, digital cameras have been in conflict with the social background in which personal computers have become popular, such as ease of recording, improved image quality through the development of image sensors, possibility of data deletion and transfer, and large recording capacity. Thus, although it is rapidly widespread, recording media (hereinafter referred to as media) are limited in terms of price and capacity as described above, and thus there are limitations on the manner of use. For example, because the media is expensive,
As mentioned above, it is normal to use a single piece of media repeatedly, such as moving to a computer and deleting it when the data is full. Street. For this reason, there may be a shortage of recording media on the road, and it is not possible to store the media containing the data as it is or upload it to a person. Therefore, it is desired to realize a large-capacity and inexpensive small medium so that data taken with a digital camera can be stored as it is or can be easily uploaded to a person. In addition, in a personal computer, it is desired to realize a large-capacity and inexpensive small medium capable of storing data and passing it to a person. [0009] In response to such a demand, a personal computer or a small-sized, low-capacity medium that can store data taken with a digital camera or personal computer data as it is, or can be easily uploaded to a person. A medium comprising a card type disk drive that can be loaded into an electronic device such as a digital camera and a magnetic disk cartridge that can be loaded into the disk drive is conceivable. That is, as such a magnetic disk cartridge, a flexible magnetic disk capable of high-density magnetic recording is rotatably accommodated in a housing having an open / close shutter,
For example, a magnetic disk cartridge having a recording capacity of 200 MB or more can be considered. As a high recording density magnetic recording medium for that purpose, a metal thin film formed by vapor deposition, a metal thin film formed by sputtering, or a barium ferrite powder or a ferromagnetic metal powder can be used. As an example of using barium ferrite powder, Japanese Patent Application No. 200 filed by the present applicant
There is 1-312864. “High recording density magnetic recording medium using barium ferrite powder” is a magnetic disk containing barium ferrite powder in the magnetic layer, and using a material capable of realizing high recording density. For example, Japanese Patent Application No. 20
A nonmagnetic layer containing nonmagnetic powder and a binder on at least one surface of a nonmagnetic support disclosed in 01-205290, and a magnetic layer containing a ferromagnetic powder and a binder that are hexagonal ferrite powders, In this order, wherein the nonmagnetic layer has an average particle size of 10 to 30 nm of carbon black with respect to 100 parts by mass of the nonmagnetic powder.
0 parts by mass, the thickness of the magnetic layer is 0.2 μm or less, and the standard deviation b of the strength relative to the average strength a of the element caused by the ferromagnetic powder by electron microanalysis is 0.00.
03 ≦ b / a ≦ 0.4, and the center plane average roughness Ra of the magnetic layer is 5 nm or less, and the 10-point average roughness Rz is 40 n.
It is a magnetic recording medium that is m or less. For magnetic disks using this material, for example, MR with high recording density is possible.
Information is recorded and reproduced using a magnetic head such as a head. According to the above media, the recording capacity is 200M.
A medium having a high recording density of B or more, preferably 500 MB or more can be realized. As a result, for example, a still image can be recorded at about 1M and 500 sheets can be recorded, and a moving image can be recorded for 30 minutes. About video content can be recorded. Accordingly, it is possible to record a moving image shot by a digital camera, a moving image distributed by a mobile phone, and the like, and it is possible to improve user convenience when using content. Of course, it can be conveniently used as an inexpensive large-capacity data storage medium in a personal computer, and its convenience is great. In general, a card-type disk drive that can be loaded into an electronic device is an electric power source connected to a socket 4 of a receiving portion of a card 2 inserted into a card slot of a PC card in the case of a personal computer as shown in FIG. In the case of a small electronic device such as a digital camera 3, the disk drive 6 is electrically connected to the socket of the receiving portion 5 on the electronic device side and loaded.
It is. Therefore, this disk drive 6 is extremely small, for example, a length of 38 mm to 55 mm and 35 m.
The magnetic disk cartridge 8 has a width of m to 51 mm and a thickness of 3 mm to 5 mm, for example, 25 mm to 36 mm.
And a thickness of 1 mm to 3 mm. In order to put such media into practical use as a specific product, as described above, the capacity is as large as possible.
In addition, it is necessary to be inexpensive. That is, it is desired that the recording capacity be larger even with the same small-sized media as in the past. In response to such a demand, if an attempt is made to make a magnetic disk cartridge with a large recording capacity and an inexpensive size, it becomes difficult to adopt the conventional structure as it is for rotating the disk. That is, when a method of driving by inserting the spindle of the drive unit into the hole of the center core as in a conventional floppy (registered trademark) disk, the disk and the center core are small, so that the spindle is twisted when inserted and removed. There is a fear. In view of such problems, an object of the present invention is to provide a magnetic disk cartridge that can be easily centered and attached and that does not cause twisting during removal. A magnetic disk cartridge according to the present invention comprises a housing and a magnetic disk having a center core rotatably accommodated in the housing. It is characterized by including a frustoconical protrusion having a truncated cone shape. The chucking structure of the magnetic disk cartridge is a chucking structure for driving the magnetic disk cartridge according to claim 1 and has a spindle rotated by a motor. While having a receiving part complementary to the protruding part of the center core, a magnet for magnetically attracting the protruding part to the bottom of the receiving part can be provided. In the magnetic disk cartridge according to the present invention, the center core of the magnetic disk is configured to include a frustoconical magnetic protrusion with a narrowed tip.
The chucking structure is such that the tip of the spindle rotated by the motor has a frustoconical protrusion on the center core of the magnetic disk cartridge and a receiving part complementary to the magnet, and magnetically attracts the protrusion to the bottom of the receiving part Since the magnetic disk is always positioned coaxially with respect to the spindle, the spindle can be easily centered. Further, since the shape of the center core is reduced, an inexpensive magnetic disk can be obtained, and the recorded magnetic disk cartridge can be stored as it is or can be used for raising to a person. Specifically, according to the present invention, it is possible to give a recording capacity of, for example, 500 MB to a disk having a size of about 28 mm. Can be recorded, and can be realized at a price of several hundred yen. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a magnetic disk cartridge according to the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view showing a magnetic disk cartridge according to an embodiment of the present invention. The magnetic disk cartridge 8 according to this embodiment includes a personal computer, a digital camera,
It is used for an electronic device such as a mobile phone, and is particularly used by being inserted into the disk drive 6 of the digital camera 3 described above. Here, when recording / reproducing information with a medium, the magnetic disk cartridge 8 is first inserted into the disk drive 6. Then, in a state where the disk drive 6 and the magnetic disk cartridge 8 are integrated, for example, the disk drive 6 and the magnetic disk cartridge 8 are inserted into a card slot (receiving portion) 5 provided in an electronic device such as the digital camera 3. And
Information is recorded on and reproduced from the magnetic disk 14 (FIG. 2) of the magnetic disk cartridge 8 by an electronic device such as the digital camera 3 via the disk drive 6. The disk drive 6 includes a drive mechanism for rotating the magnetic disk 14 of the magnetic disk cartridge 8 loaded from the magnetic disk insertion slot 7, a magnetic head for magnetically recording and reproducing information on the magnetic disk 14, and a drive. An electrical connection unit for electrically connecting the mechanism and the magnetic head to an electronic circuit in the electronic device is provided. When recording / reproducing information on the magnetic disk cartridge 8, information is recorded / reproduced on the magnetic disk 14 rotated by the rotation mechanism of the disk drive 6 using a magnetic head. Information to be recorded at this time is input from the electrical connection unit, and information reproduced from the magnetic disk 14 is output from the electrical connection unit. Next, the structure of the magnetic disk cartridge 8 of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view of the magnetic disk cartridge 8 shown in FIG. 3A and 3B are cross-sectional views of the magnetic disk cartridge 8 shown in FIG. 2, wherein FIG. 3A is a cross-sectional view of the chucked magnetic disk cartridge 8, and FIG. A cross-sectional view is shown. First, a description will be given with reference to FIG. A magnetic disk cartridge 8 includes a rectangular resin housing 10.
And an opening / closing shutter 12, a magnetic disk 14, and the like. A hollow portion 16 (FIG. 3) is formed in the housing 10, and the magnetic disk 14 is rotatably accommodated in the hollow portion 16. A shutter 12 is attached to the housing 10 so as to be openable and closable. When the magnetic disk cartridge 8 is loaded in the disk drive 6 and information is recorded / reproduced, the shutter 1
2 is opened so that the magnetic disk 14 is exposed. The detailed specifications of the magnetic disk cartridge 8 are described in detail in the above-mentioned “magnetic recording medium” (Japanese Patent Application No. 2001-31864) filed by the applicant of the present invention. To do. Next, the structure of the magnetic disk cartridge 8 will be further described with reference to FIG. An extremely small center core 18 is attached coaxially to the magnetic disk 14 at the center of the disk-shaped magnetic disk 14 disposed in the hollow portion 16 in the housing 10. The center core 18 is formed as a projecting portion of a magnetic material such as stainless steel. Specifically, in FIG. 3, the center core 18 is formed in a truncated cone shape in which the portion away from the magnetic disk 14, that is, the tip is narrowed, and is tapered around the periphery. It has a surface 26. In the present embodiment, the diameter of the magnetic disk 14 is set in the range of about 25 mm to 35 mm, and the diameter of the base of the center core 18, that is, the surface attached to the magnetic disk 14 is 4 m.
m or less. Since the center core 18 is very small as described above, recording can be performed up to the inner peripheral portion of the magnetic disk 14, and the recording capacity can be increased. A circular opening 2 is formed in the lower part of the housing 10 corresponding to the center core 18.
0 is formed, and the center core 18 is exposed to the outside through the opening 20. As a result, the center core 1
8 can be chucked to an external spindle 22 serving as a driving unit. The spindle 22 is a metal cylindrical shaft and is driven to rotate by a motor (not shown). At the upper end of the spindle 22 is a receiving portion 24 that receives the center core 18.
Is formed coaxially with the spindle 22. Receiver 24
Is formed in a concave portion complementary to the center core 18,
A tapered surface 28 having the same inclination as the tapered surface 26 around the center core 18 is provided. A permanent magnet 30 is disposed in the recess 32 at the bottom of the receiving portion 24. When chucking, the center core 18 and the spindle 22 are fixed to each other by attracting the center core 18 magnetically by the permanent magnet 30. Yes. When chucking, the taper surface 26 of the center core 18 and the taper surface 28 of the spindle 22 cooperate with each other, and the taper surface 28 becomes a leading surface, so that the center core 18 can be easily coaxial with the spindle 22. Position. In this way, the magnetic disk 14 can be easily centered without play on the spindle 22. The recess 32 has a circular shape, and the magnet 30 has a cylindrical shape that fits into the recess 32. The magnet 30 is fixed to the recess 32 by an appropriate method such as adhesion or press fitting. In order to remove the magnetic disk cartridge 8 from the spindle 22, it is only necessary to pull it away, and there is no possibility of causing a problem of twisting as in the prior art. The above chucking structure is not a method of inserting a spindle into the hole of the center core as in the prior art.
There is no risk of twisting because the receiving part on the spindle side receives the protruding part of the center core. In addition, since the center core is configured by a truncated cone-shaped protrusion,
The center core can be made small, and the area of the center core in the magnetic disk can be made very small. That is, since the recordable area can be expanded to the inner periphery of the magnetic disk, a magnetic disk having a larger capacity than a conventional magnetic disk of the same size can be obtained. The magnetic disk cartridge 8 of the present invention has been described above.
However, the present invention is not limited to the above embodiment. That is, the present invention is particularly suitable for the ultra-small magnetic disk cartridge 8. However, the present invention is not limited to this and can be applied to a relatively large size magnetic recording medium.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a magnetic disk cartridge according to an embodiment of the present invention. FIG. 2 is a perspective view of the magnetic disk cartridge shown in FIG. 1A is a cross-sectional view of a magnetic disk cartridge that has been chucked, and FIG. 2B is an enlarged cross-sectional view of a main part that shows a magnetic disk and a spindle separated from each other. Housing 14 Magnetic disk 18 Center core 22 Spindle 24 Receiving portion 30 Magnet

Claims (1)

What is claimed is: 1. A magnetic disk cartridge comprising a housing and a magnetic disk having a center core rotatably accommodated in the housing, wherein the center core has a truncated cone shape with a narrowed tip. A magnetic disk cartridge comprising a protrusion of a magnetic material.