Patent Publication Number: US-2003231427-A1

Title: Magnetic disk cartridge

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a magnetic disk cartridge in which a discoid magnetic disk medium is contained in a case.  
       [0003] 2. Description of the Related Art  
       [0004] Conventionally, a flexible disk has been provided as a type of magnetic disk media. The flexible disk is capable of magnetically recording a signal on magnetic layers thereof which are formed on both sides of a discoid base made of a flexible polyester sheet and the like, by use of a magnetic head.  
       [0005] This flexible disk typically has a hard center core mounted in a center portion of the disk. The flexible disk has been provided as a magnetic disk cartridge of which the entirety thereof is contained in either a plastic or metal shell. Since the flexible disk has advantages in that it is inexpensive to produce and easy to handle, the flexible disk has been mainly used as a recording medium for computers.  
       [0006] Incidentally, an increase in a recording capacity has been constantly demanded for the magnetic disk cartridge.  
       [0007] Improvements in track density and density of recording lines (increases in the numbers of TPI and BPI) are examples of means for increasing the recording capacity of the magnetic disk cartridge. However, if the numbers of TPI and BPI were excessively increased for the magnetic disk media, the magnetic disk media would be easily affected by a change in a floating state of a magnetic head when recording and reproducing data. Consequently, there is a risk that reliability of the data will be lost, and there would inevitably be a limitation on the degree of increases in the number of TPI and BPI.  
       [0008] In addition, enlargement of a recording area of the magnetic disk media is another effective means for increasing the recording capacity. Since members such as the center core are mounted inside an inner circle area in a discoid magnetic disk, it is hard to enlarge the recording area in the inner circle area. The recording area hardly increases in accordance with an increase in the radius of the inner circle area. Thus, for enlargement of the recording area, it is effective to increase the radius of the outer circle area of the recording area by increasing the outer circumference of the magnetic disk. However, due to the increase in the outer circumference of the magnetic disk, it is required to enlarge an area of a flat surface of a cartridge which incorporates this magnetic disk. Accordingly, there is a problem of losing portability and utility of the cartridge if the area of the flat surface is extremely enlarged.  
       SUMMARY OF THE INVENTION  
       [0009] The present invention has been developed in consideration of the above-described problems. It is an object of the present invention to provide a magnetic disk cartridge of which recording capacity has been increased without enlarging the area of a flat surface thereof.  
       [0010] The magnetic disk cartridge of the present invention includes a rotatable magnetic disk medium, a housing and a shutter member. The housing contains the magnetic disk medium and is provided with an opening portion for a recording/reproducing head of a recording/reproducing device to access the magnetic disk medium. The shutter member is movable so as to open/close the opening portion. The shutter member is moved by a shutter opening/closing member of the recording/reproducing device to a position where the opening portion is opened upon insertion of the magnetic disk cartridge into the recording/reproducing device. A plurality of magnetic disk media -are contained in the housing.  
       [0011] According to the magnetic disk cartridge of the present invention, by having the plurality of magnetic disk media contained in the housing, it is possible to increase the recording capacity of the magnetic disk cartridge in proportion to the number of the disks without enlarging the area of the flat surface of the cartridge. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0012]FIG. 1 is a schematic diagram of a magnetic disk cartridge according to an embodiment of the present invention.  
     [0013]FIG. 2 is a schematic diagram of when the above magnetic disk cartridge is at a shutter opening position.  
     [0014]FIG. 3 is a structural diagram of the above magnetic disk cartridge.  
     [0015]FIG. 4 is a sectional view of the above magnetic disk cartridge.  
     [0016]FIG. 5 is a front view of a magnetic disk drive which is compatible with the above magnetic disk cartridge.  
     [0017]FIG. 6 is a sectional view of the above magnetic disk drive. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0018] The present invention will be detailed below based on an embodiment illustrated in figures. FIG. 1 is a schematic diagram of a magnetic disk cartridge according to an embodiment of the present invention. FIG. 2 is a schematic diagram of when the magnetic disk cartridge is at a shutter opening position. FIG. 3 is a structural diagram of the magnetic disk cartridge. FIG. 4 is a sectional view of the magnetic disk cartridge.  
     [0019] The magnetic disk cartridge  10  comprises a flat housing composed of first and second half shells  11  and  12 . The flat housing contains magnetic disk media  14  and  15 , a first shutter member, a second shutter member, a spring  24  and the like. The magnetic disk media  14  and  15  are fixedly attached to and held by a center core  13 . The first shutter member includes components  16 ,  17 ,  18  and  19 . The second shutter member includes components  20 ,  21 ,  22  and  23 . The spring  24  urges the first and second shutter members to the direction of a closed position.  
     [0020] The first shutter member is structured such that the magnetic disk medium  14  is sandwiched between the components  16  and  17  and the magnetic disk medium  15  is sandwiched between the components  18  and  19 . A shutter knob  16   a  is fixedly attached to the component  16 .  
     [0021] Similar to the first shutter member, the second shutter member is structured such that the magnetic disk medium  14  is sandwiched between the components  20  and  21  and the magnetic disk medium  15  is sandwiched between the components  22  and  23 . A shutter knob  23   a  is fixedly attached to the component  23 .  
     [0022] When the first and second shutter members are at the closed position, the first shutter member partially overlaps with the second shutter member, thereby preventing dust from entering the magnetic disk cartridge upon conveyance of the cartridge.  
     [0023] The first half shell  11  is provided with a magnetic head insertion portion  11   a,  an opening portion  11   b  and an opening portion  11   c.  The magnetic head insertion portion  11   a  enables a magnetic head of a recording/reproducing section, which is included in the magnetic disk drive described later, to access the magnetic disk media  14  and  15  by partially exposing the magnetic disk media  14  and  15 . The opening portion  11   b  is for inserting a spindle shaft and the like provided in a drive. The opening portion  11   c  enables the shutter knob  16   a  to be movable.  
     [0024] Similar to the first half shell  11 , the second half shell  12  is provided with a magnetic head insertion portion  12   a,  an opening portion  12   b  and an opening portion  12   c.  The magnetic head insertion portion  12   a  enables the magnetic head of the recording/reproducing portion, which is included in the magnetic disk drive described later, to access the magnetic disk media  14  and  15  by partially exposing the magnetic disk media  14  and  15 . The opening portion  12   b  is for inserting the spindle shaft and the like provided in the drive. The opening portion  12   c  enables the shutter knob  23   a  to be movable.  
     [0025] Opening/closing of the first and second shutter members are automatically performed as described below when the magnetic disk cartridge  10  is inserted into/removed from the drive.  
     [0026] Accompanied by insertion of the magnetic disk cartridge  10  into the drive, the shutter knobs  16   a  and  23   a  respectively fixedly attached to the first and second shutter members are engaged by engaging members in the drive. Further insertion of the magnetic disk cartridge  10  causes the shutter knobs  16   a  and  23   a  to move downward in FIG. 1, relative to the housing. Accordingly, the first and second shutter members are respectively moved by rotation to the open position shown in FIG. 2. Consequently, the magnetic disk media  14  and  15  will be in an exposed state.  
     [0027] When removing the magnetic disk cartridge  10  from the drive, since the first and second shutter members are urged to the direction of the closed position by the spring  24 , the first and second members are moved to the closed position with the steps in reverse order of steps described above.  
     [0028] The magnetic disk cartridge  10  constituted as described above is structured such that either of the first and second half shells  11  and  12  can be on the upper side to have the same configuration. Therefore, the magnetic disk cartridge  10  can be inserted into the magnetic disk drive which is compatible with this magnetic disk cartridge  10  with either of the first and the second half shell  11  and  12  on the upper side.  
     [0029] Next, the magnetic disk drive which is compatible with the magnetic disk cartridge  10  will be described. FIG. 5 is a front view of the magnetic disk drive which is compatible with the magnetic disk cartridge  10 . FIG. 6 is a sectional view of the magnetic disk drive.  
     [0030] The magnetic disk drive  30  is provided with a recording/reproducing section which records and reproduces a signal on either the magnetic disk medium  14  or  15  incorporated into the magnetic disk cartridge  10  and a magnetic disk driving section for driving the rotations of the magnetic disk media  14  and  15 . Moreover, cutouts  31   a  are provided at a magnetic disk cartridge insertion entrance  31  of this magnetic disk drive  30  so that the shutter knobs  16   a  and  23   a  provided on the magnetic disk cartridge  10  do not interfere with the magnetic disk cartridge insertion entrance  31  during insertion, when the shutter is in the closed position.  
     [0031] The recording/reproducing section is provided with a pair of suspension members  33  and magnetic heads  32 . The pair of suspension members  33  are provided for the upper and lower surfaces of the magnetic disk medium, which is on the lower side of the magnetic disk cartridge  10  inserted into the drive. The magnetic heads  32  are attached to the tip of the suspension members  33 .  
     [0032] The magnetic heads  32  are each provided with a slider, and the slider is structured such that a thin film magnetic head having a recording/reproducing head gap and the like are fixedly attached to a part of the slider. According to its design, the above slider produces pressure that causes it to float from the surface of the magnetic disk medium or pressure causing it to be attracted to the surface of the magnetic disk medium by an air stream generated by the rotation of the magnetic disk media. The slider approaches and moves away from the surfaces of the magnetic disk medium in accordance with the high-speed rotation of the magnetic disk medium. Thereafter, contact load of the magnetic head  32  is set at a predetermined value based on the relationship between the design of the slider and the spring forces of the suspension members  33 .  
     [0033] The upper and lower suspension members  33  are held by a suspension supporting portion  34 . The suspension supporting portion  34  rotates in both directions such that the magnetic heads  32 , which are held by the suspension members  33 , are movable from the center portion, excluding the region of the center core  13 , to the outer circumference of the magnetic disk medium.  
     [0034] The magnetic disk driving section holds the magnetic disk cartridge  10  at a predetermined position and chucks the center core  13  which is holding the magnetic disk media  14  and  15  by the spindle shaft  35  and a hub chuck  36 . A drive motor  37  drives the spindle shaft  35  and the hub chuck  36  to rotate the magnetic disk media  14  and  15  at a predetermined rotational speed.  
     [0035] When recording/reproducing signals on the magnetic disk medium, the magnetic disk medium is rotated at the predetermined rotation speed by the magnetic disk driving section. The magnetic heads  32  are inserted into the magnetic head insertion portion of the magnetic disk cartridge  10 . The magnetic heads  32  are made to approach the magnetic disk medium which is on the lower side in the magnetic disk cartridge  10  inserted into the drive  30  to magnetically record or reproduce signals.  
     [0036] In the case where recording/reproducing signals on the magnetic disk medium which is on the upper side in the magnetic disk cartridge  10  inserted into the drive  30 , the magnetic disk cartridge  10  is once removed from the drive  30  and flipped. Thereafter, the magnetic disk cartridge  10  is re-inserted into the drive  30  to record/reproduce signals on the magnetic disk medium which had been on the upper side before removal.  
     [0037] As described above, by containing two magnetic disk media in a housing, it is possible to double the recording capacity of a magnetic disk cartridge compared with a normal magnetic disk cartridge which contains only one magnetic disk medium, without enlarging an area of a flat surface of the cartridge.  
     [0038] Note that the manner in which two magnetic disk media are contained in a housing is not limited to the aspect of the embodiment described above. Moreover, the number of the magnetic disk media contained in the housing is not limited to that of the above description, and the housing may contain three or more magnetic disk media.