Abstract:
The present invention provides a cartridge accommodating a disk therein which is inserted into a cartridge holder, the cartridge holder being provided with a mis-insertion protection member. The mis-insertion protection member is located within an insertion path along which the cartridge is inserted into the cartridge holder. The cartridge has a substantially rectangular shape. The cartridge has a corner portion at each of four corners of the substantially rectangular shape, the corner portion being shaped so as to abut on the mis-insertion protection member to move the mis-insertion protection member out of the insertion path. The cartridge has at least two mis-insertion protection mechanisms for engaging with the mis-insertion protection member so as to prevent the cartridge from being mis-inserted. The cartridge has two side surfaces which are substantially perpendicular to a surface of the disk and extend along a direction substantially parallel to a direction in which the cartridge is inserted into the cartridge holder. A mis-insertion protection mechanism of the at least two mis-insertion protection mechanisms is provided on each of the side surfaces.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a mis-insertion protection mechanism in a magnetic or optical disk cartridge for preventing the cartridge from being inserted into a disk drive in a wrong direction.  
           [0003]    2. Description of the Related Art  
           [0004]    A magnetic or optical disk cartridge is generally in a rectangular shape and has a window opened for receiving an optical pickup and a shutter for opening/closing the window. There are two types of such cartridges: a single-sided cartridge (for use with a single-sided disk) and a double-sided cartridge (for use with a double-sided disk). A single-sided cartridge can be inserted into a disk drive only in one direction. A double-sided cartridge can be inserted into a disk drive in either one of two directions (i.e., it can be inserted with either one of the front side and the reverse side facing up). When a cartridge is inserted in a direction other than the right direction(s), a mis-insertion protection mechanism in the cartridge hits a stopper provided in the disk drive so that the cartridge cannot be inserted any further.  
           [0005]    A conventional single-sided cartridge has a mis-insertion protection mechanism provided by differently shaping one of the four corners from the other corners. For example, as shown in FIG. 12, a 3.5″ floppy disk cartridge  101  includes a corner  102  on the front edge thereof, which is chamfered. The other three corners  103 ,  104  and  105  of the cartridge  101  are rounded for easy insertion and easy handling of the cartridge  101 , as well as for an aesthetic design.  
           [0006]    [0006]FIG. 13 illustrates an exemplary cartridge holder  106  for use in a disk drive receiving the cartridge  101 . The cartridge holder  106  is provided with a mis-insertion protection pin  107  made of a torsion spring. One end of the mis-insertion protection pin  107  is bent at about 90°, thereby forming a stopper  108 , and the other end  107 A is secured on an outer surface of the cartridge holder  106 .  
           [0007]    The stopper  108  extends through a guide hole  109  of the cartridge holder  106  to be within the insertion path of the cartridge  101  (i.e., a path along which the cartridge  101  is inserted). The stopper  108  abuts a tab portion  110  of the cartridge holder  106  and is urged away from a side  111  thereof by virtue of the bias of the torsion spring.  
           [0008]    Referring to FIGS. 14, 15 and  16 , a mis-insertion protection function provided when the cartridge  101  is inserted into the cartridge holder  106  will be described. First, a case where the cartridge  101  is inserted correctly (in the right direction) will be described. As the cartridge  101  is inserted into the cartridge holder  106  in the right direction as illustrated in FIG. 14, the chamfered corner  102  hits the stopper  108 .  
           [0009]    Since the corner  102  is chamfered, the insertion of the cartridge  101  forces the stopper  108  out of the insertion path of the cartridge  101  by overcoming the bias of the torsion spring (in the direction indicated by arrow A in FIG. 14), thereby resulting in a state as illustrated in FIG. 15. Thus, the cartridge  101  is allowed to be inserted further into the cartridge holder  106 .  
           [0010]    Next, a case where the cartridge  101  is inserted in a wrong direction will be described referring to FIG. 16. As the cartridge  101  is inserted into the cartridge holder  106  in the wrong direction as illustrated in FIG. 16, the corner  103  hits the stopper  108 . Since the corner  103  is not chamfered, the insertion of the cartridge  101  does not force the stopper  108  in the direction indicated by arrow A.  
           [0011]    Therefore, the cartridge  101  cannot be inserted further into the cartridge holder  106 , thus providing the mis-insertion protection function. The mis-insertion protection function is similarly provided when the cartridge  101  is inserted from the corner  104  (or  105 ) (FIG. 12).  
           [0012]    Japanese Laid-Open Publication No. 57-113466 describes an exemplary mis-insertion protection mechanism for a double-sided cartridge as illustrated in FIG. 17. Both of the insertion-side corners  172 A and  172 B are chamfered, so that the cartridge exhibits the same profile whether it is faced up or faced down. Thus, the cartridge can be inserted into the cartridge holder whether it is faced up or faced down.  
           [0013]    Regarding the optical disk, there are one-sided optical disks (having a recording surface only on one side) and double-sided optical disks (having a recording surface on both sides). Recently, there is a need in the art to accommodate a single-sided disk in a single-sided cartridge and a double-sided disk in a double-sided cartridge, respectively, so that they can be used in the same disk drive. Along with the increase in the recording density of an optical disk, there is also a demand in the art for a cartridge accommodating a small-diameter optical disk.  
           [0014]    Since a pickup for optical disks is larger than a magnetic recording pickup, an optical disk cartridge has a larger window and also requires a larger area for the motion of the shutter (“shutter motion area”). Therefore, in a cartridge accommodating a small-diameter optical disk, the shutter motion area comes close to the side edges, and thus the corners, of the cartridge.  
           [0015]    In such an optical disk cartridge desired in the art, it is difficult to provide a mis-insertion protection mechanism by differentiating the shape of one or two corner(s) from that of the other corners as in the prior art. This is because it is difficult to provide a large enough chamfer at the corner(s) to differentiate the corner(s) from the other rounded corners such that a mis-insertion protection function can be provided.  
         SUMMARY OF THE INVENTION  
         [0016]    According to one aspect of this invention, there is provided a cartridge accommodating a disk therein which is inserted into a cartridge holder, the cartridge holder being provided with a mis-insertion protection member. The mis-insertion protection member is located within an insertion path along which the cartridge is inserted into the cartridge holder. The cartridge has a substantially rectangular shape. The cartridge has a corner portion at each of four corners of the substantially rectangular shape, the corner portion being shaped so as to abut on the mis-insertion protection member to move the mis-insertion protection member out of the insertion path. The cartridge has at least two mis-insertion protection mechanisms for engaging with the mis-insertion protection member so as to prevent the cartridge from being mis-inserted. The cartridge has two side surfaces which are substantially perpendicular to a surface of the disk and extend along a direction substantially parallel to a direction in which the cartridge is inserted into the cartridge holder. A mis-insertion protection mechanism of the at least two mis-insertion protection mechanisms is provided on each of the side surfaces.  
           [0017]    In one embodiment of the invention, the mis-insertion protection mechanism includes a slot formed in at least one of the side surfaces.  
           [0018]    In one embodiment of the invention, the slot includes: an inclined guide section comprising a surface inclined with respect to the side surfaces for guiding the mis-insertion protection member; and a stopper arranged substantially perpendicular to the side surfaces for contacting the mis-insertion protection member to prevent the cartridge from being mis-inserted.  
           [0019]    In one embodiment of the invention, the two side surfaces comprise a first side surface and a second side surface. The corner portions comprise first corner portions along the first side surface and second corner portions along the second side surface. The at least two mis-insertion protection mechanisms comprise a first mis-insertion protection mechanism provided in the first side surface and a second mis-insertion protection mechanism provided in the second side surface. A distance between the first mis-insertion protection mechanism and one of the first corner portions is substantially equal to a distance between the second mis-insertion protection mechanism and a corresponding one of the second corner portions.  
           [0020]    In one embodiment of the invention, the cartridge comprises a double-sided cartridge.  
           [0021]    In one embodiment of the invention, the cartridge comprises a single-sided cartridge.  
           [0022]    In one embodiment of the invention, the two side surfaces comprise a first side surface and a second side surface. The at least two mis-insertion protection mechanisms comprise a first mis-insertion protection mechanism provided in the first side surface, a second mis-insertion protection mechanism provided in the second side surface, and a third mis-insertion protection mechanism provided either in the first side surface or in the second side surface.  
           [0023]    In one embodiment of the invention, the corner portions comprise first corner portions along the first side surface and second corner portions along the second side surface. The distance between the first mis-insertion protection mechanism and one of the first corner portions is substantially equal to a distance between the second mis-insertion protection mechanism and a corresponding one of the second corner portions.  
           [0024]    In one embodiment of the invention, the distance between the first mis-insertion protection mechanism and the one of the first corner portions is substantially equal to a distance between the third mis-insertion protection mechanism and a corresponding one of the first or second corner portions.  
           [0025]    In one embodiment of the invention, the cartridge comprises a single-sided cartridge.  
           [0026]    In one embodiment of the invention, the cartridge further comprises a concave-shaped auto-loading slot provided in at least one of the side surfaces. The auto-loading slot is located such that the mis-insertion protection member engages with the third mis-insertion protection mechanism after the mis-insertion protection member passes over the auto-loading slot.  
           [0027]    In one embodiment of the invention, the cartridge comprises a single-sided cartridge.  
           [0028]    In one embodiment of the invention, the cartridge further comprises an opening and a shutter for opening/closing the opening. The mis-insertion protection mechanism is provided outside of a motion area of the shutter.  
           [0029]    In one embodiment of the invention, the shutter is movable toward either side of the opening.  
           [0030]    In one embodiment of the invention, the cartridge comprises a double-sided cartridge.  
           [0031]    In one embodiment of the invention, the shutter is movable toward only one side of the opening.  
           [0032]    In one embodiment of the invention, the cartridge comprises a single-sided cartridge.  
           [0033]    According to another aspect of this invention, there is provided an auto-loading device for loading a cartridge of the present invention. The auto-loading device comprises: a cartridge holder for holding the cartridge; and an auto-loading mechanism for loading the cartridge. The cartridge holder includes a mis-insertion protection member for engaging with the mis-insertion protection mechanism so as to prevent the cartridge from being mis-inserted. The auto-loading mechanism includes an engagement protrusion for engaging with the auto-loading slot.  
           [0034]    In one embodiment of the invention, the auto-loading mechanism further includes a detector for detecting the cartridge.  
           [0035]    In one embodiment of the invention, the auto-loading mechanism further comprises a movable plate coupled with the engagement protrusion. The movable plate starts moving along with the cartridge in response to the detector detecting the cartridge.  
           [0036]    Thus, the invention described herein makes possible the advantage of providing a mis-insertion protection mechanism in a magnetic or optical disk cartridge for reliably preventing mis-insertion of the cartridge, which can suitably be used in a cartridge with a large shutter motion area, and which can be used either in a single-sided cartridge or in a double-sided cartridge.  
           [0037]    This and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]    [0038]FIG. 1 is a schematic diagram illustrating a double-sided cartridge according to Example 1 of the present invention;  
         [0039]    [0039]FIG. 2 is a schematic diagram illustrating a cartridge holder provided in an optical disk apparatus which receives the double-sided cartridge of Example 1;  
         [0040]    [0040]FIG. 3A is a perspective view illustrating how the double-sided cartridge of Example 1 is inserted into the cartridge holder;  
         [0041]    [0041]FIG. 3B is a plan view illustrating how the double-sided cartridge of Example 1 is inserted into the cartridge holder;  
         [0042]    [0042]FIG. 4A is a perspective view illustrating how the double-sided cartridge of Example 1 is inserted into the cartridge holder;  
         [0043]    [0043]FIG. 4B is a plan view illustrating how the double-sided cartridge of Example 1 is inserted into the cartridge holder;  
         [0044]    [0044]FIG. 5A is a perspective view illustrating how the double-sided cartridge of Example 1 is inserted into the cartridge holder;  
         [0045]    [0045]FIG. 5B is a plan view illustrating how the double-sided cartridge of Example 1 is inserted into the cartridge holder;  
         [0046]    [0046]FIG. 6 is a schematic diagram illustrating a single-sided cartridge according to Example 2 of the present invention;  
         [0047]    [0047]FIG. 7 is a perspective view illustrating a mis-insertion of the single-sided cartridge of Example 2;  
         [0048]    [0048]FIG. 8 is a schematic diagram illustrating a single-sided cartridge according to Example 3 of the present invention;  
         [0049]    [0049]FIG. 9 is an exploded perspective view illustrating a cartridge holder provided in an optical disk apparatus which receives the single-sided cartridge of Example 3;  
         [0050]    [0050]FIG. 10 is a perspective view illustrating how the single-sided cartridge of Example 3 is inserted into the cartridge holder;  
         [0051]    [0051]FIG. 11 is a perspective view illustrating how the single-sided cartridge of Example 3 is inserted into the cartridge holder;  
         [0052]    [0052]FIG. 12 is a schematic diagram illustrating a conventional single-sided cartridge;  
         [0053]    [0053]FIG. 13 is a schematic diagram illustrating a cartridge holder provided in an optical disk apparatus which receives the conventional single-sided cartridge;  
         [0054]    [0054]FIG. 14 is a plan view illustrating how the conventional single-sided cartridge is inserted into the cartridge holder;  
         [0055]    [0055]FIG. 15 is a plan view illustrating how the conventional single-sided cartridge is inserted into the cartridge holder;  
         [0056]    [0056]FIG. 16 is a plan view illustrating how the conventional single-sided cartridge is inserted into the cartridge holder; and  
         [0057]    [0057]FIG. 17 is a schematic diagram illustrating a conventional double-sided cartridge. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0058]    Hereinafter, the present invention will be described in more detail by way of illustrative examples with reference to the accompanying drawings.  
       Example 1  
       [0059]    [0059]FIG. 1 is a schematic diagram illustrating a double-sided cartridge  1  according to Example 1 of the present invention. FIG. 2 is a schematic diagram illustrating a cartridge holder  10  provided in an optical disk apparatus which receives the double-sided cartridge  1 . FIGS. 3A, 3B,  4 A,  4 B,  5 A and  5 B are diagrams illustrating how the double-sided cartridge  1  is inserted into the cartridge holder  10 .  
         [0060]    Referring to FIG. 1, the double-sided cartridge  1  accommodating an optical disk therein has a window  2  on both sides thereof for receiving a pickup of the disk drive, and a U-shaped slidable shutter  3  for opening/closing the window.  
         [0061]    The shutter  3  is movable toward either side of the window  2 , and is biased by a shutter spring (not shown) to close the window  2 . As the cartridge  1  is inserted into the disk drive, the shutter  3  hits a shutter opener (not shown) provided in the disk drive, which then moves the shutter  3  to open the window  2 . The same shutter opener can move the shutter  3  to open the window  2  also when the cartridge  1  is inserted with its reverse side facing up, because the shutter  3  is movable toward either side of the window  2 .  
         [0062]    All of the four corners  4  of the cartridge  1  have the same rounded shape. A mis-insertion protection slot  5  is provided along both side edges of the cartridge  1  near the rear edge (opposite to the shutter  3 ) thereof. The slot  5  comprises an inclined guide section  6  for guiding a mis-insertion protection pin  11  (further described later) and a stopper section  7 .  
         [0063]    Now, an operation of inserting the cartridge  1  into the cartridge holder  10  will be described. As illustrated in FIG. 2, the cartridge holder  10  is provided with the mis-insertion protection pin  11  made of a torsion spring. One end of the mis-insertion protection pin  11  is bent at about 90°, thereby forming a stopper  12 , and the other end  11 A is secured on an outer surface of the cartridge holder  10 .  
         [0064]    The stopper  12  extends through a guide hole  13  of the cartridge holder  10  to be present within the insertion path of the cartridge  1 . The stopper  12  abuts a tab portion  14  of the cartridge holder  10  and is urged away from a side thereof by virtue of the bias of the torsion spring. In this state, the stopper  12  is designed to meet the rounded portion of the corner  4  of the cartridge  1 .  
         [0065]    First, a case where the cartridge  1  is inserted correctly (in the right direction) will be described. As the cartridge  1  is inserted into the cartridge holder  10  in the right direction as illustrated in FIGS. 3A and 3B, the rounded portion of the corner  4  hits the stopper  12 . Since the corner  4  has a rounded shape, the insertion of the cartridge  1  forces the stopper  12  out of the insertion path of the cartridge  1  (in the direction indicated by arrow B in FIGS. 3A and 3B), thereby resulting in a state as illustrated in FIGS. 4A and 4B, thus allowing the cartridge  1  to be inserted further into the cartridge holder  10 .  
         [0066]    Since the cartridge  1  is a double-sided cartridge, it exhibits the same profile whether it is faced up or faced down. Therefore, the cartridge  1  can of course be inserted into the cartridge holder  10  as illustrated in FIGS. 3A, 3B,  4 A and  4 B with the reverse side thereof facing up.  
         [0067]    Next, a case where the cartridge  1  is inserted in a wrong direction, i.e., from the rear edge thereof, will be described referring to FIGS. 5A and 5B. Since the corners  4  on the rear edge of the cartridge  1  have the same rounded shape as that of the corners  4  on the front edge thereof, the cartridge  1  can be inserted to a certain depth into the cartridge holder  10  as illustrated in FIGS. 3A and 3B.  
         [0068]    As the cartridge  1  is further inserted, the stopper  12  is urged into the slot  5  by virtue of the bias of the torsion spring and guided along the inclined guide section  6  of the slot  5  so as to hit the stopper section  7 , as illustrated in FIGS. 5A and 5B. Since the stopper section  7  is generally perpendicular to a side surface  10 A of the cartridge  1 , there is no force to move the stopper  12  in the direction indicated by arrow B.  
         [0069]    Thus, the cartridge  1  cannot be inserted further into the cartridge holder  10 , thereby providing the mis-insertion protection function. Still, the cartridge  1  can be pulled out from the cartridge holder  10  as the stopper  12  is guided along the guide section  6  out of the slot  5 .  
         [0070]    The mis-insertion protection function is similarly provided when the cartridge  1  is inserted into the cartridge holder  10  from the rear edge thereof with the reverse side facing up. In this way, the mis-insertion protection mechanism can be provided separately from the corner  4  and outside the motion area of the shutter  3 . Thus, desirable freedom is provided in designing the shutter  3 , thereby allowing the shutter  3  motion area to be as large as that in Example 1 (see FIG. 1).  
       Example 2  
       [0071]    [0071]FIG. 6 is a schematic diagram illustrating a first single-sided cartridge  20  according to Example 2 of the present invention. FIG. 7 is a diagram illustrating a mis-insertion of the first single-sided cartridge  20 . In FIGS. 6 and 7, like reference numerals to those in the previously discussed figures denote like elements, will not further be described below.  
         [0072]    The first single-sided cartridge  20  is generally the same as the double-sided cartridge  1  according to Example 1 except for the following points. First, the shutter  3  is movable toward only one side of the window  2  because the cartridge  20  is a single-sided cartridge. Moreover, a second slot  21 , having a similar shape to that of the mis-insertion protection slot  5 , is provided along one side edge of the cartridge  20  near the front edge thereof. The side on which the second slot  21  is provided is opposite to the side toward which the shutter is moved to open the window  2 . The second slot  21  is different from the slot  5  in that the second slot  21  does not extend through the thickness of the cartridge  20 . The distance S 1  between the second slot  21  and the front edge of the cartridge  20  is generally the same as the distance S 2  between the slot  5  and the rear edge of the cartridge  20 .  
         [0073]    Referring to FIG. 7, a mis-insertion protection function will be described, which is provided when the single-sided cartridge  20  is inserted into the cartridge holder  10  from the front edge, but with the reverse (wrong) side thereof facing up. The cartridge  20  is inserted to a certain depth into the cartridge holder  10  as illustrated in FIGS. 3A and 3B. As the cartridge  20  is further inserted, the stopper  12  is urged into the second slot  21  by virtue of the bias of the torsion spring and guided along the inclined guide section  6  of the second slot  21  so as to hit the stopper section  7 , as illustrated in FIG. 7. Since the stopper section  7  is generally perpendicular to a side surface  20 A of the cartridge  20 , there is no force to move the stopper  12  in the direction indicated by arrow B.  
         [0074]    Therefore, the cartridge  20  cannot be inserted any further, thereby providing the mis-insertion protection function.  
         [0075]    In other directions, the single-sided cartridge  20  is inserted into the cartridge holder  10  as described above with respect to the double-sided cartridge  1  in Example 1.  
         [0076]    By such a structure, the single-sided cartridge  20  is prevented from being inserted into the cartridge holder  10  with the reverse side thereof facing up. As described above, the slots  5  and  21  are located at generally the same distance (S 1  and S 2 ) respectively from the front edge and the rear edge of the cartridge  20 , thereby stopping the mis-inserted cartridge  20  at generally the same depth in the cartridge holder  10 . Thus, a user can easily recognize the mis-insertion.  
         [0077]    Moreover, as in Example 1, the slots  5  and  21  can be provided separately from the corner  4  and outside the motion area of the shutter  3 , thereby facilitating the cartridge design.  
         [0078]    Furthermore, in Example 2, the second slot  21  does not extend to the front or upper surface of the cartridge  20 , so that the single-sided cartridge  20 , as viewed from the front side, exhibits the same profile as that of a double-sided cartridge, thereby adding an aesthetic advantage to the cartridge  20 . Functionally, however, the second slot  21  may of course extend through the thickness of the cartridge  20 .  
         [0079]    While all of the four corners of the cartridge  20  are rounded in Example 2, the corners may have any other shape as long as the mis-insertion protection pin in the disk drive can be appropriately guided around the corners.  
       Example 3  
       [0080]    [0080]FIG. 8 is a schematic diagram illustrating a second single-sided cartridge  22  according to Example 3 of the present invention. FIG. 9 is a schematic diagram illustrating a cartridge holder  10 A of an optical disk apparatus which receives the second single-sided cartridge  22 . FIGS. 10 and 11 are diagrams illustrating how the second single-sided cartridge  22  is inserted into the cartridge holder  10 A. In FIGS.  8  to  11 , like reference numerals to those in the previously discussed figures denote like elements, will not further be described below.  
         [0081]    The second single-sided cartridge  22  is generally the same as the first single-sided cartridge  20  according to Example 2 except for the following points. The single-sided cartridge  22  has a concave auto-loading slot  24  provided along both side edges of the cartridge  22  near the front edge thereof, with a second slot  23  being provided on the rear side of the auto-loading slot  24  (The second slot  23  is generally the same in shape as the second slot  21  of Example  2 ). The auto-loading slot  24  engages with an auto-loading mechanism (further described later) provided in the optical disk apparatus to automatically load the cartridge  22  into the apparatus.  
         [0082]    Next, the cartridge holder  10 A having the auto-loading mechanism will be described below. Referring to FIG. 9, the cartridge holder  10 A includes a window  25  on both side surfaces thereof and a plurality of pins  26  provided integrally on the upper surface. The cartridge holder  10 A further includes a movable plate  27 , which is provided with a plurality of elongated guide grooves  28  respectively engaging with the pins  26 . The movable plate  27  also includes a bent portion  36 . A plate spring  29 , having an engagement protrusion  29 A at the tip thereof, is provided at both ends of the bent portion  36 .  
         [0083]    A rack  30  is provided on the rear side of the movable plate  27 . The rack  30  meshes with a pinion gear  32  fit around a shaft of a motor  31  which is fixed in the apparatus. The movable plate  27  further includes a detection section  33 . A first sensor  34  and a second sensor  35 , both of which are light emitting-receiving devices, are fixed on the detection section  33 . Such a light emitting-receiving device can emit light downwardly so as to detect if the cartridge  22  is present under the light emitting-receiving device by detecting light reflected by the cartridge  22 .  
         [0084]    The auto-loading operation will now be described. When the cartridge  22  is inserted into the cartridge holder  10 A in a predetermined (right) direction, the corner  4  of the cartridge  22  hits the stopper  12 , as described above in Example 1, thereby moving the stopper  12  out of the insertion path of the cartridge  22 . The cartridge  22  is inserted further into the cartridge holder  10 A while one side surface abuts the stopper  12 . Since the auto-loading slot  24  is in a concave shape which does not extend to the upper surface of the cartridge  22 , the stopper  12  passes over, and is not urged into, the auto-loading slot  24 .  
         [0085]    As the cartridge  22  is inserted further into the cartridge holder  10 A, the presence of the cartridge  22  is detected by the first sensor  34  and then by the second sensor  35  of the detection section  33 . Meanwhile, the engagement protrusion  29 A of the plate spring  29  is pushed by the corner  4  of the cartridge  22  out of the insertion path of the cartridge  22  through the window  25 , and then slides against the side surface of the cartridge  22 . As the cartridge  22  is inserted further into the cartridge holder  10 A, the engagement protrusion  29 A engages into the auto-loading slot  24  of the cartridge  22  by virtue of the resilient force of the plate spring  29 , thereby holding the cartridge  22 .  
         [0086]    [0086]FIG. 10 illustrates the cartridge  22  upon completion of the manual loading of the cartridge  22  into the cartridge holder  10 A. The first sensor  34  and the second sensor  35  of the detection section  33  successively detect the cartridge  22  with a predetermined time lag therebetween. Thus, the motor  31  is activated and starts rotating the pinion gear  32 . The rotary force is transferred to the rack  30 , thereby moving the movable plate  27  rearwardly (in the direction indicated by arrow R 1 ) along with the cartridge  22  being held by the movable plate  27 .  
         [0087]    After moving the movable plate  27  for a certain distance, the motor  31  stops, thereby completing the auto-loading operation. FIG. 11 illustrates the cartridge  22  upon completion of the auto-loading operation. By employing such an auto-loading operation, it is possible to improve the user&#39;s operational feeling.  
         [0088]    When the cartridge  22  is inserted with the reverse side thereof facing up, the stopper  12  (FIG. 9) passes over the auto-loading slot  24  (FIG. 8) and then hits the stopper section  7  of the second slot  23  (FIG. 8), thereby providing the mis-insertion protection function.  
         [0089]    As described above, the second single-sided cartridge  22  has the auto-loading slot  24  shaped in a concave shape, so that the cartridge  22  provided with the mis-insertion protection slot  23  along the side surface thereof can be automatically loaded.  
         [0090]    According to the present invention, a mis-insertion protection mechanism as described above is provided along one or both of the side edges of the cartridge, thereby successfully providing a reliable mis-insertion protection function to a disk cartridge, in which it is difficult to differentiate the respective shapes of the corners from one another.  
         [0091]    Various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the scope and spirit of this invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description as set forth herein, but rather that the claims be broadly construed.