Abstract:
The present invention provides a recording tape cartridge including: a rectangular case having, at a corner portion, an opening for pulling-out of one end of a recording tape, and accommodating the recording tape; a cover member opening and closing the opening; and an opening opening/closing mechanism holding the cover member at the case, and selectively moving the cover member between a position of opening the opening and a position of closing the opening.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a recording tape cartridge which rotatably accommodates a single reel on which is wound a recording tape such as a magnetic tape or the like.  
           [0003]    2. Description of the Related Art  
           [0004]    Recording tapes, such as magnetic tapes or the like, are used as external recording media for computers and the like. A recording tape cartridge, which requires little space for storage, and in which a large amount of information can be recorded, and which accommodates a single reel on which the recording tape is wound, is used for the recording tape.  
           [0005]    An opening is formed in a case of the recording tape cartridge. The recording tape is pulled out from the opening, and is taken-up onto a take-up reel of a drive device. Conventionally, various measures have been devised in order for dust and the like to not enter in from the opening and adhere to the recording tape.  
           [0006]    In a recording tape cartridge  100  shown in FIG. 13, an opening  104  is formed in a side wall  102 A (a side wall running along a case loading direction A) of a case  102 . The opening  104  is opened and closed by a door  106  which slides along the loading direction.  
           [0007]    However, at the position of the opening  104 , an operation member of the drive device, which pulls-out a leader member (i.e., a leader pin  108 ) which is attached to an end portion of a magnetic tape T which is the recording tape, must move around from the lateral direction of the case  102  and pull-out the leader pin  108 . Thus, space for the operation member to move around (i.e., move non-rectilinearly) must be ensured in the drive device. Moreover, the mechanism for moving the operation member around becomes complex, and the drive device becomes large. In addition, the path along which the magnetic tape T is pulled out becomes long with respect to a take-up reel  110 .  
           [0008]    In a recording tape cartridge  112  shown in FIG. 14, an opening  116  is formed in a front wall  114 A (a front wall facing the case loading direction A) of a case  114 . The opening  116  is opened and closed by a pivoting-type door  118  which opens and closes around a shaft.  
           [0009]    In this recording tape cartridge  112 , because the opening  116  is formed at the front wall  114 A, there is no need for the operation member of the drive device to pull-out the magnetic tape T by moving around from the lateral direction. However, because the door  118  outwardly opens widely, space must be ensured in the drive device such that nothing interferes with the opening and closing operations of the door  118 . Therefore, the drive device becomes large.  
           [0010]    In a recording tape cartridge  120  shown in FIG. 15, an opening  124  is formed by cutting off a corner portion of a case  122 . The opening  124  is opened and closed directly by a leader block  126  which is a leader member connected to the end portion of the magnetic tape T.  
           [0011]    If the leader block  126  only functions as a door for closing the opening  124 , no problems arise even if scratches are formed in or dust adheres to the leader block  126 . However, the leader block  126  is pulled out by an operation member of the drive device, and is fit-together with a hub  130  of a take-up reel  128  of the drive device. Thus, if scratches are formed in or dirt adheres to the leader block  126 , the leader block  126  cannot fit-together well with the hub  130 , and there is the concern that the conveying of the magnetic tape T may be adversely affected. Moreover, because the leader block  126  forms a portion of a take-up surface which takes-up the magnetic tape T, there is the risk that the data recorded on the magnetic tape T will be damaged or that regions which cannot be recorded will arise due to scratches formed in or dirt adhering to the leader block  126 .  
           [0012]    Further, the leader block  126  is merely anchored at the edge of the opening  126 . Thus, there is the concern that, if the case  122  is dropped, the leader block  126  will come apart from the opening  124 . Moreover, because the leader block  126  is larger than a leader pin, the number of constraints on the configuration of the case  122  increases.  
         SUMMARY OF THE INVENTION  
         [0013]    In view of the aforementioned, an object of the present invention is to provide a recording tape cartridge having an opening which enables an operating mechanism of a drive device to pull-out a recording tape along the shortest path, and in which a door for closing the opening and a leader member for the pulling-out of the recording tape are formed as separate members, and which enables a drive device to have a compact design.  
           [0014]    A first aspect of the invention is a recording tape cartridge comprising: a rectangular case having, at a corner portion, an opening for pulling-out of one end of a recording tape, and accommodating the recording tape; a cover member opening and closing the opening; and an opening opening/closing mechanism holding the cover member at the case, and selectively moving the cover member between a position of opening the opening and a position of closing the opening.  
           [0015]    In the above-described structure, when the recording tape cartridge is to be used, the recording tape cartridge is loaded into a drive device. The leader member is pulled-out from the opening by the operating mechanism, and the recording tape is pulled-out from the case. The leader member is accommodated at the hub of the drive device as the recording tape is being pulled-out. In this state, the hub is driven to rotate, and the recording tape is successively pulled-out from the case while being taken-up onto the outer peripheral surface of the hub. Information is recorded on or played back from the recording tape by a recording/playback head or the like disposed along a predetermined tape path.  
           [0016]    Here, the opening is formed by cutting off a corner portion of the rectangular case in the direction of loading the case into a drive device. Therefore, the plane of opening of the opening is directed in the direction of loading the case into the drive device and in a direction orthogonal to the direction of loading and to the thickness direction of the case. Namely, the operation mechanism can access the leader member from the loading direction side, from the direction orthogonal to the loading direction and to the thickness direction of the case, or from the direction of the corner portion.  
           [0017]    Thus, it is possible to design a drive device in which the path for the pulling-out of the recording tape is the shortest, and there is no need for a drive mechanism in which the operation mechanism moves around and chucks the leader member. Thus, a compact and inexpensive drive device can be designed. Simultaneously, the entire path along which the magnetic tape travels also becomes shorter as a matter of course, and thus, the wear due to contact between the magnetic tape and a tape guide can be reduced.  
           [0018]    Further, due to the operating mechanism of the drive device operating the opening opening/closing mechanism, the cover member is moved between a position of closing the opening and a position of opening the opening, and the opening is closed or opened. Namely, the opening is closed and opened by the cover member which is provided as a member separate from the leader member. Thus, it is difficult for the leader member to be scratched or become dirtied. Therefore, the pulling-out of the recording tape and the conveying of the recording tape within the drive device are not affected.  
           [0019]    Even if the case is dropped, because the cover member is held at the case by the opening opening/closing mechanism, the cover member does not come apart from the case, and dust and the like do not inadvertently enter in from the opening. Note that “cover member” is a comprehensive term encompassing members which can close the opening, such as a door, a lid, a shutter, and the like.  
           [0020]    As one example of the opening opening/closing mechanism, the opening opening/closing mechanism can operate the cover member to open and close in the minimum space by sliding the cover member so as to open or close the opening. The drive device can thereby be made compact.  
           [0021]    Further, the cover member may be disposed at the inner side of the opening, and when opening or closing the opening, may move along a locus which is defined such that the cover member does not jut out further than the region defined by the outer configuration of the case. In this way, it is difficult for a user to intentionally open and close the cover member. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    [0022]FIG. 1 is an exploded perspective view showing the overall structure of a recording tape cartridge relating to an embodiment of the present invention.  
         [0023]    [0023]FIG. 2 is a perspective view showing the relationship between an opening and a door of the recording tape cartridge relating to the embodiment of the present invention.  
         [0024]    [0024]FIG. 3 is a perspective view showing the relationship between the opening and the door of the recording tape cartridge relating to the embodiment of the present invention.  
         [0025]    [0025]FIG. 4 is a perspective view showing the relationship between the opening and the door of the recording tape cartridge relating to the embodiment of the present invention.  
         [0026]    [0026]FIG. 5 is a plan view showing the operation of opening and closing the door of the recording tape cartridge relating to the embodiment of the present invention.  
         [0027]    [0027]FIG. 6 is a plan view showing the operation of opening and closing the door of the recording tape cartridge relating to the embodiment of the present invention.  
         [0028]    [0028]FIG. 7 is a plan view showing the operation of opening and closing the door of the recording tape cartridge relating to the embodiment of the present invention.  
         [0029]    [0029]FIG. 8 is a perspective view showing a state in which the door of the recording tape cartridge relating to the embodiment of the present invention is opened by a door opening/closing arm.  
         [0030]    [0030]FIG. 9 is a plan view showing a state in which the door of the recording tape cartridge relating to the embodiment of the present invention is opened by the door opening/closing arm.  
         [0031]    [0031]FIG. 10 is a plan view showing the state in which the door of the recording tape cartridge relating to the embodiment of the present invention is opened by the door opening/closing arm.  
         [0032]    [0032]FIG. 11 is a plan view showing the state in which the door of the recording tape cartridge relating to the embodiment of the present invention is opened by the door opening/closing arm.  
         [0033]    [0033]FIG. 12A is a view, as seen with the upper case removed, showing a modified example of a second guide groove which forms the recording tape cartridge relating to the embodiment of the present invention, and is a plan view showing a state in which the opening is closed.  
         [0034]    [0034]FIG. 12B is a view, as seen with the upper case removed, showing the modified example of the second guide groove which forms the recording tape cartridge relating to the embodiment of the present invention, and is a plan view showing a state in the midst of opening or closing the opening.  
         [0035]    [0035]FIG. 12C is a view, as seen with the upper case removed, showing the modified example of the second guide groove which forms the recording tape cartridge relating to the embodiment of the present invention, and is a plan view showing a state in which the opening is opened.  
         [0036]    [0036]FIG. 13 is a perspective view showing the overall structure of a conventional recording tape cartridge.  
         [0037]    [0037]FIG. 14 is a perspective view showing the overall structure of a conventional recording tape cartridge.  
         [0038]    [0038]FIG. 15 is a perspective view showing the overall structure of a conventional recording tape cartridge. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0039]    A recording tape cartridge  10  relating to an embodiment of the present invention will now be described. Note that, for convenience of explanation, the direction of loading the recording tape cartridge  10  into a drive device is denoted by arrow A, and a direction orthogonal to the direction of arrow A is denoted by arrow B.  
         [0040]    As shown in FIG. 1, at the recording tape cartridge  10 , a single reel  15 , on which is wound a magnetic tape T serving as a recording tape which is an information recording/playback medium, is rotatably accommodated within a case  12  which is substantially rectangular as seen in plan view.  
         [0041]    The case  12  is formed by superposing together a pair of cells  14 ,  16  at each of which a loading direction corner portion has been cut off. An accommodating space for the magnetic tape T is formed at the interior of the case  12 . The cut-off corner portions of peripheral walls  18  of the cells  14 ,  16  form an opening  20  for the pulling-out of the magnetic tape T.  
         [0042]    In this way, by forming the opening  20  at the corner portion of the case  12 , the plane of opening of the opening  20  is directed in direction A and in direction B. Therefore, a chucking mechanism  22  (see FIG. 4) can access and chuck a leader pin  24  from direction A, or from direction B, or from between direction A and direction B.  
         [0043]    The area over which the pin stands  26 , which hold the leader pin  24 , can be set, can thereby be broadened. Namely, because the region over which the chucking mechanism  22  can chuck the leader pin  24  is wide, the position at which the pin stands  26  are to be set can be determined in accordance with the specifications of the drive device which is chucking from the direction of arrow A or from the direction of arrow B. Therefore, the degrees of freedom in designing the drive device can be increased.  
         [0044]    Screw bosses  28  are formed at the edges of the opening  20 , i.e., at the final end portions of the peripheral wall  18  of the cell  14 . Screws  48  are screwed in and fixed into the screw bosses  28  from the upper side cell  16 . In this way, even if the case  12  is dropped, the opening  20 , which is disadvantageous in terms of strength, does not deform or buckle and the position thereof does not shift, due to the weight of the entire recording tape cartridge  10 .  
         [0045]    In the same way as at the cell  14 , the peripheral wall  18  and the screw bosses  28  (see FIG. 2) are formed at the cell  16 . Note that, in order to avoid repetitive description, description will be given hereinafter by using the cell  14  as an example, but it is to be understood that the cell  16  has a similar structure.  
         [0046]    The diameter of the thread of the screw  48  is, for example, φ2.0 mm, and the outer diameter of the screw boss  28  is φ4.0 mm. Further, instead of screws, projections may be made to project from the cell  16  at positions corresponding to the screw bosses  28 , and fit-together holes which fit together with these projections may be provided at the cell  14 , and the projections and fit-together holes may be fit-together. However, in this case, it is preferable that the cell  16  and the cell  14  be fastened together by screws at places within a radius of 30 mm from these regions of fitting-together. Moreover, the surfaces of the peripheral walls  18  of the cells  14  and  16  which oppose one another may be fixed by welding.  
         [0047]    At the area where the pin stands  26  are set (i.e., in a vicinity of the opening), the plate thickness of each of the upper cell  16  and the lower cell  14  is 2 mm, which is thicker than the other areas. Moreover, the cells are formed from a polycarbonate (PC) material.  
         [0048]    This is in order to improve the strength in vicinities of the pin stands  26  which are the holding (positioning) positions of the leader pin  24  which is most important in the functions of the recording tape cartridge  10  (i.e., which should be correctly anchored by the chucking mechanism  22  at the time when the magnetic tape T is to be pulled-out), and is in order to prevent positional offset from arising due to the impact caused by dropping or the like.  
         [0049]    The pin stands  26  are formed in the shapes of semicircular tubes, and the end portions of the leader pin  24  which stands erect are held in recess portions  26 A of the pin stands  26 . The sides of the outer peripheral walls of the pin stands  26 , at which sides the magnetic tape T is pulled-out, are open, and form entrances/exits for the leader pin  24  to enter therein and exit therefrom.  
         [0050]    Annular grooves  24 A are formed at both end portions of the leader pin  24 . The annular grooves  24 A are anchored by hooks  30  of a chucking mechanism  22 . Further, the annular grooves  24 A are positioned at the outer sides of the transverse direction end portions of the magnetic tape T, such that the hooks  30  of the chucking mechanism  22  do not contact and scratch the magnetic tape T.  
         [0051]    Second guide grooves  32 , which are inclined at a predetermined angle with respect to the plane of opening of the opening  20 , are formed in vicinities of the pin stands  26 . The second guide grooves  32  are formed such that, when the inner surfaces of the upper cell  16  and the lower cell  14  are brought face-to-face to each other, the second guide grooves  32  are at the same positions. Guide pins  36 , which project in the transverse direction from one end side of a rectangular door  34  which opens and closes the opening  20 , are slidably inserted into the second guide grooves  32 .  
         [0052]    The plate width (the height) of the door  34  and the opening height of the opening  20  are substantially the same, and the plate length of the door  34  is longer than the opening width of the opening  20 . Namely, the slidability of the door  34  is maintained, and the door  34  blocks dust and the like from entering in from the opening  20 .  
         [0053]    Guide pins  38  project in the transverse direction from the other end side of the door  34 . The guide pins  38  are inserted into first guide grooves  40  which are formed parallel to the peripheral walls  18  which run along direction A. The first guide grooves  40  also are formed such that, when the inner surfaces of the upper cell  16  and the lower cell  14  are brought face-to-face to each other, the first guide grooves  40  are at the same positions.  
         [0054]    The guide pins  38  are inserted into the first guide grooves  40 , the guide pins  36  are inserted into the second guide grooves  32 , and the door  34  is disposed so as to span between the second guide grooves  32  and the first guide grooves  40 . In this way, as shown in FIGS. 5 through 7, while pivoting, with the guide pins  38  serving as the axis of pivoting, the door  34  slides at the inner side of the peripheral walls  18  so as to open the opening  20 . Further, at the time of closing the opening  20 , conversely, the door  34  is slid so as to be pushed toward the opening  20 , and is set substantially parallel to the plane of opening of the opening  20  so as to close the opening  20 .  
         [0055]    Moreover, bent portions  32 A, which are bent outwardly, are formed at the front ends (the end portions at the side in the loading direction A) of the second guide grooves  32 . The bent portions  32 A are parallel to the first guide grooves  40 . Accordingly, as shown in FIG. 5, when the guide pins  38  are positioned at the front ends (the opening side end portions) of the first guide grooves  40  and the guide pins  36  are positioned in the bent portions  32 A and the door  34  is closing the opening  20 , even if a user pushes the door  34  in the direction of opening the door  34 , the guide pins  36  catch on the bent portions  32 A, and the door  34  cannot be easily opened.  
         [0056]    Note that, in the present embodiment, the bent portions  32 A are formed along the direction of arrow A. However, the angle of inclination of the bent portions  32 A with respect to the longitudinal direction of the second guide grooves  32  can be set to an arbitrary value between  50 ° and 150°, and the bent portions  32 A can also be formed so as to bend in a curved shape.  
         [0057]    A triangular rib  42  extends along the transverse direction at the outer surface of the one end side of the door  34 . The rib  42  anchors on a picking portion  46  of a door opening/closing arm  44  provided at a drive device which will be described later, such that, when the case  12  is inserted into the drive device, sliding force along the bent portions  32 A is applied to the door  34 . Thus, the guide pins  36  move away from the bent portions  32 A and move along the second guide grooves  32 , and the door  34  is opened.  
         [0058]    Further, an anchor hole  52 , at which one end of a torsion spring  50  is anchored, is formed in the central portion of the door  34 . A cylindrical supporting column  54  is inserted into the coil portion of the torsion spring  50  which is anchored on the anchor hole  52 . The other end of the torsion spring  50  is anchored on an anchor pin  55 . Force in the closing direction is always applied to the door  34  by the torsion spring  50 .  
         [0059]    A gear opening  58  for exposing a reel gear to the exterior, is provided in the central portion of the lower cell  14 . A reel  15  is driven to rotate within the case  12  by the reel gear meshing with a drive gear of the drive device. The reel  15  is held, such that it does not joggle, by peripheral walls  60  which partially project from the inner surfaces of the cells  14 ,  16  and which are on a circular locus. Note that the anchor pin  55  is provided at the outer side of the peripheral wall  60  and does not contact the reel  15 .  
         [0060]    Next, description will be given of the basic structure of the chucking mechanism  22 , the door opening/closing arm  44  which opens and closes the door  34 , and a take-up reel (not shown) of the drive device into which the recording tape cartridge  10  of the present embodiment is loaded.  
         [0061]    As shown in FIG. 4, the chucking mechanism  22  has the hooks  30  which chuck the leader pin  24 , and a pivoting arm  62  which makes the hooks  30  carry out their chucking operation. When the door  34  is opened by the door opening/closing arm  44  and the case  12  is stopped at a predetermined position within the drive device, the pivoting arm  62  pivots, anchors on the leader pin  24  held at the pin stands  26 , pulls-out the magnetic tape T from the opening  20 , and moves the magnetic tape T to the hub of a take-up reel (not illustrated). An attaching groove, which the leader pin  24  fits into, is formed in the hub. When the pivoting arm  62  makes the leader pin  24  be accommodated in the attaching groove, the hub is rotated, and the magnetic tape T is taken-up onto the reel along a predetermined path.  
         [0062]    Next, the door opening/closing arm will be described.  
         [0063]    As shown in FIG. 8, the door opening/closing arm  44  is pivotably provided above the loading portion of the recording tape cartridge  10 . At the position shown in FIG. 9, pivoting of the door opening/closing arm  44  in the counterclockwise direction is restrained, and the door opening/closing arm  44  is positioned. The picking portion  46 , which is bent toward the center of pivoting of the door opening/closing arm  44 , is formed at the distal end portion of the door opening/closing arm  44 . When the recording tape cartridge  10  is loaded into the drive device, the distal end of the picking portion  46  enters into a gap formed between the surfaces of the rib  42  of the door  34  and the screw boss  28 , which surfaces face one another.  
         [0064]    Guide grooves  64  are formed along the loading direction in the base surface of the loading portion of the recording tape cartridge  10 . Ribs  66  formed at the case  12  engage with the guide grooves  64 , such that the recording tape cartridge  10  can be loaded into the drive device without tending to the left or the right. Moreover, a stopper  68  stands erect at the far back side of the base surface. The stopper  68  is formed in a configuration which follows along the shape of the corner portion of the case  12 , and functions as a member for positioning the case  12  in the horizontal direction.  
         [0065]    The opening  20  of the case  12  is formed by cutting-off a loading direction corner portion. Therefore, merely by changing the cut-off shape of the corner portion, the corner portion can be made to function also as a portion for identifying the recording tape cartridge in a recording tape cartridge library (which is equipped with a plurality of shelves in which recording tape cartridges are stocked, and which has the functions of removing a recording tape cartridge in accordance with a request therefor and loading the recording tape cartridge into a drive device). In this way, there is no need to form a separate identifying portion at the case. Therefore, it is possible to prevent the structure of a metal mold for the case from becoming complex, and to prevent the strength of the case from being insufficient and the dust-proof ability of the case from deteriorating.  
         [0066]    Next, operation of the present embodiment will be described.  
         [0067]    As shown in FIG. 8 and FIG. 9, when the recording tape cartridge  10  is loaded into the drive device along the direction of arrow A, the rib  42  of the door  34  anchors on the picking portion  46  of the door opening/closing arm  44 .  
         [0068]    When the recording tape cartridge  10  is pushed in, as shown in FIG. 10, by utilizing the force of insertion, the door opening/closing arm  44 , while pivoting clockwise, slides the door  34  in the direction of opening. Then, as shown in FIG. 11, when the recording tape cartridge  10  is pushed in until the corner portion (the opening portion) of the case  12  abuts the stopper  68 , the door  34  slides to the inner side of the case  12  such that the opening  20  is completely opened.  
         [0069]    Here, as shown in FIG. 4, the hooks  30  of the chucking mechanism  22  pull-out the leader pin  24  which is held at the pin stands  26 , and guide the leader pin  24  to the hub of the reel. Because the hooks  30  can access the leader pin  24  from direction A (the loading direction), the path for pulling-out the magnetic tape T is the shortest, and the entire path along which the magnetic tape T travels becomes shorter as a matter of course. Accordingly, the wear due to contact of the magnetic tape T and a tape guide or the like can be reduced.  
         [0070]    Further, because there is no need for a drive mechanism in which the hooks  30  move around and chuck the leader pin  24 , it is possible to design a drive device which is compact and has a low manufacturing cost.  
         [0071]    Next, when the recording tape cartridge  10  is to be removed, the case is pushed back in the direction opposite to direction A by an unillustrated ejecting mechanism. Thus, the door  34  is pushed in the closing direction by the torsion spring  50 . Due to the spring force, the picking portion  46  is pushed by the rib  42  of the door  34 , and, as shown in FIG. 10, the door opening/closing arm  44  returns to its original position while pivoting counterclockwise.  
         [0072]    In accordance with the above-described operations, the opening  20  is opened and closed, and the leader pin  24  is protected by the door  34  which closes the opening  20 . Therefore, it is difficult for the leader pin  24  to be scratched or dirtied. Thus, the pulling-out and the conveying of the magnetic tape within the drive device are not affected.  
         [0073]    Further, even if the case  12  is dropped, the door  34  is held in the case  12  by the second guide grooves  32 , the first guide grooves  40 , and the guide pins  36 ,  38 . Therefore, the door  34  does not come apart from the case  12 , and dust and the like do not inadvertently enter in from the opening  20 .  
         [0074]    Moreover, because the door  34  opens and closes by sliding, the door  34  can be operated to open and close in a minimum amount of space. The drive device can thereby be made compact. Further, the door  34  slides toward the inner side so as to not jut out from the region defined by the outer configuration of the case  12  (the door  34  is positioned further inwardly than the screw bosses at the both sides of the opening). Therefore, it is difficult for a user to intentionally open and close the door  34 , and it is difficult for the door  34  to break.  
         [0075]    The door may have a configuration which covers the guide grooves when the door is slid, such that dust and the like can be prevented from accumulating in the guide grooves, and the sliding operation of the door is not hindered.  
         [0076]    In the above-described embodiment, the second guide grooves (cam grooves)  32 , which are for regulating rotation of the door  34  around the guide pins  38 , are formed to be rectilinear. However, the present invention is not limited to the same. For example, in place of the second guide grooves  32 , second guide grooves  160  such as shown in FIGS. 12A, 12B and  12 C may be provided. (The torsion spring  50  is not shown in FIGS. 12A, 12B and  12 C.)  
         [0077]    The second guide groove  160  is formed in a substantial V shape, as seen in plan view, in which an angle of inclination θ 1 , with respect to the direction of arrow A of a first inclined portion  162  provided at the rear of the bent portion  144 , is smaller than an angle of inclination θ 2 , with respect to the direction of arrow A of a second inclined portion  164  provided at the rear of the first inclined portion  162 .  
         [0078]    In this structure, the pressure angle of the guide pin  36  with respect to the second guide groove  160  can be made to be smaller than that in the previously-described embodiment. Namely, a pressure angle α is defined as the angle formed by an imaginary line connecting the contact point at which the guide pin  36  abuts the second guide groove  160  and the axial center of the guide pin  38  which is the center of rotation of the guide pin  36 , and a normal line of the second guide groove  160  at this contact point. Generally, the pressure angle or is preferably from 15° to 60°. However, in the present embodiment, by keeping the maximum value of the pressure angle α to 55°, the door  34  can be operated even more smoothly.  
         [0079]    Note that the both transverse direction groove walls of the second inclined portion  164  of the second guide groove  160  may be formed in circular arc shapes such that the corresponding groove walls of the first inclined portion  162  are lines tangential thereto.  
         [0080]    Further, in the above-described embodiment, the first guide groove  40  and the second guide groove  32  ( 160 ) are provided independent of one another. However, the present invention is not limited to the same, and the first guide groove  40  and the second guide groove  32  ( 160 ) may be formed continuously with one another.  
         [0081]    Moreover, in the above-described embodiment, a magnetic tape T is used as the recording tape. However, the present invention is not limited to the same. The recording tape is to be interpreted as being an elongated tape-shaped information recording/playback medium on which information can be recorded and from which recorded information can be played back. The recording tape cartridge relating to the present invention can be applied to recording tapes of any recording/playback system.  
         [0082]    Because the present invention has the above-described structure, the operation member of the drive device can pull the recording tape out from the opening of the recording tape cartridge along the shortest path, and the drive device can be designed to be compact. Further, because the door which closes the opening and the leader member for the pulling-out of the recording tape are separate members, it is difficult for the leader member to be scratched. Moreover, because the opening is provided at the corner portion of the recording tape cartridge, the range of positions at which the leader member can be set is broadened, and the degrees of freedom in designing the drive device are increased.