Disc cartridge with a shutter

Abstract: A disc cartridge includes a cartridge main body (4) which accommodates an optical recording medium (5), such as an optical disc or a magneto-optical disc, and which includes an aperture (8) to expose the optical recording medium (5) at least partially to outside, a shutter (12) to open or close the aperture (8), a shutter resetting spring to bias the shutter towards a side closing the aperture and a shutter locking member (24) to maintain the shutter (12) at a position closing the aperture (8). A shutter opening/closing member introducing groove (16) having its open end on a side (9) of the cartridge main body normal to the shutter sliding direction, is formed along the front side (11) of the cartridge main body (4) parallel to the shutter sliding direction and has the free end of the shutter locking member (24) exposed partially to the groove (16) to enable the disc cartridge to be loaded to a cartridge loading section of recording/reproducing apparatus with the shutter sliding direction as the introducing or loading direction.

Description: The invention relates to a disc cartridge accommodating a disc-shaped recording medium and having a shutter mounted thereon to open or close an aperture formed in a cartridge main body. As an optical recording medium for musical sound, picture or other information signals, there has hitherto been employed a read-only optical disc on which desired information signals, such as musical sound information signals, which have been previously recorded can be reproduced after loading the disc on a reproducing apparatus by the user. As an optical recording medium in which pre-recorded signals may be erased and re-recorded, there has also been proposed a magneto-optical disc in which a magnetic thin film is used as a recording layer. With the optical recording media, such as the optical or magneto-optical discs, recording and/or reproduction of information signals of an extremely high density is possible because a laser beam is employed for recording and/or reproduction of information signals. For example, with an optical disc devoted to reading of pre-recorded information signals, reproduction of musical sound signals continuing for about 74 minutes is possible with a disc which is 12 cm in diameter. There has also been proposed an optical disc or a magneto-optical disc with which a higher recording density may be achieved. For example, there is proposed a method of recording information signals after signal compression for improving the recording density. With a higher recording density, it becomes possible to record the same volume of information signals as that recorded on a conventional optical recording medium on an optical recording medium of a smaller diameter. On the other hand, with the optical or magneto-optical disc, with which a higher recording density may be realised, the slightest scores or deposition of the smallest amount of foreign matter on the signal recording surface results in marked deterioration in recording and/or reproducing characteristics. For this reason, this type of optical recording medium needs to be accommodated in a sealable cartridge to prevent scoring or deposition of foreign matter during recording, handling or during storage when the recording medium is not loaded on the recording and/or reproducing apparatus. The optical recording medium needs to be accommodated reliably in and protected by the cartridge during storage. On the other hand, it is required of the recording/reproducing apparatus, having the optical recording medium, thus reduced in size on account of the improved recording density, as a recording medium, to be similarly reduced in size in order to keep up with the reduction in size of the optical recording medium. European Patent Specification No. 0391588 discloses a disk cartridge having a pair of identifying devices formed in a major surface thereof. One of the identifying devices indicates whether or not recording is permitted and the other indicating device - not user adjustable - indicates the type of the disk. European Patent Specification No. 0195535 discloses a shutter opening and closing device for a disk cartridge, and a recording/reproducing device for use therewith. The shutter of the cartridge is openable by means of a pin moving through a groove in the cartridge to open the shutter. According to the invention there is provided a magneto-optical disc cartridge comprising a cartridge main body accommodating a disc-shaped magneto-optical recording medium therein and having apertures radially to expose a portion of either side of the magneto-optical recording medium to outside thereby to allow signals to be recorded onto or reproduced from said medium; a shutter slidably mounted on the cartridge main body to open and close the apertures; a resilient flexible shutter locking member to maintain the shutter in a position closing the apertures; a shutter opening/closure member introducing groove having an opening end on a side of the cartridge main body normal to a sliding direction of the shutter, the groove being formed on a front side of the cartridge main body extending parallel to the sliding direction of the shutter; indicating means provided in a major surface of the cartridge main body to indicate the storage capacity of the magneto-optical recording medium; mistaken recording inhibiting/detecting means provided in the major surface of the cartridge main body to indicate recordability or non-recordability of information signals on the magneto-optical recording medium; and a notch for indicating that said disc cartridge is a magneto-optical disc cartridge, said notch being formed on the side of said cartridge in proximity to the front side of the cartridge main body. In such a disc cartridge an optical recording medium accommodated in a cartridge main body may be protected positively and safeguarded against scoring or deposition of foreign matter such as during storage. Simplification of recording and/or reproducing apparatus to be used with such a disc cartridge may contribute to reduction in size of the apparatus When the disc cartridge is not loaded on the recording and/or reproducing apparatus, the shutter can be biased by a shutter resetting spring to a position of closing the aperture which can expose at least a portion of the optical recording medium to outside along its radius, and can be locked by the shutter locking member. When the disc cartridge is to be loaded on the recording/ reproducing apparatus, the shutter opening/closure member provided on the apparatus is intruded into the groove from the opening end situated on the side of the cartridge main body extending in a direction normal to the sliding direction of the shutter, and is moved therein along the introducing direction of the cartridge main body to deflect the shutter locking member resiliently to unlock and slide the shutter against the bias of the shutter resetting spring to open the aperture. The invention is illustrated by way of example in the accompanying drawings, in which: Figure 1 is a perspective view showing an illustrative disc cartridge as viewed from its upper side that is outside of the scope of the invention; Figure 2 is a perspective view of the disc cartridge shown in Figure 1, as viewed from its lower side; Figure 3 is a partial perspective view showing an opening end of a shutter opening/closure member inserting groove provided in the disc cartridge shown in Figure 1; Figure 4 is a plan view showing the state in which the shutter opening/closure member is introduced at the opening end of the shutter opening/closure member inserting groove; Figure 5 is a plan view similar to Figure 4 and showing the state in which a shutter locking member is thrust and flexed by the shutter opening/closure member to unlock the shutter; Figure 6 is a plan view similar to Figure 4 and showing the state in which the shutter has been moved to a position of opening the aperture; Figure 7 is a perspective view similar to Figure 1 and showing a disc cartridge according to the invention, as viewed from the upper side; Figure 8 is a perspective view, similar to Figure 2, showing the disc cartridge of Figure 7 from its lower side; Figure 9 is a perspective view showing the lower surface of the disc cartridge, as viewed from the rear side; Figure 10 is a partial plan view showing a mistaken recording inhibiting member provided in the lower half, with a mistaken recording detection opening being closed; Figure 11 is a partial plan view of the lower half showing the state in which the mistaken recording inhibiting member has been moved to a position of opening the mistaken recording detection opening; Figure 12 is a perspective view showing a modification of the mistaken recording detection means, as viewed from the lower side of the disc cartridge; Figure 13 is a partial perspective view of a disc cartridge in which a rupturable piece has been removed to open the mistaken recording detection opening; Figure 14 is a perspective view of a disc cartridge according to the invention, as viewed from the upper side; and Figure 15 is a perspective view of the disc cartridge of Figure 14 from its lower side. The illustrative disc cartridge 1 is outside of the scope of the invention and accommodates a reproduce-only optical disc with which high density recording of information signals is achieved and on which are recorded musical sound signals continuing for at least 60 and more specifically for 74 minutes. The disc cartridge 1 comprises a rectangular cartridge main body 4 comprising an upper half 2 and a lower half 3 abutted and connected to each other, and a read- or reproduce-only optical disc 5 rotatably accommodated in the cartridge main body. The optical disc 5 has a diameter R 1 about 64 mm and has a centring hole 6. Referring to Figure 2, the mid portion of the lower half 3 constituting the cartridge main body 3 is formed with a disc table introducing opening 7 which can expose the rim of the centring hole of the optical disc 5 to outside and into which is introduced a disc table of a disc driving device for the optical disc 5 when the disc cartridge 1 is loaded into the recording/reproducing apparatus. The lower half 3 is also formed with a signal readout aperture 8 radially to expose a portion of the signal recording surface of the optical disc 5 to outside. The aperture 8 is provided between a front side 11 of the cartridge main body 4 and the disc table introducing opening 7 at a mid position between the sides 9 and 10 of the cartridge main body 4, and is in the form of a rectangle of a size large enough to expose a portion of the signal recording surface of the optical disc 5 to outside between the inner and outer peripheries of the disc. A shutter 12 to close the aperture 8 of the signal reading aperture 8 is slidably mounted on the cartridge main body 4. The shutter 12 is fabricated by bending a thin metal plate or a plate of synthetic resin, and is constituted by a connecting section 13 slidable along the front side of the cartridge main body 4, a shutter section 14 having its proximal end connected to the connection section 13 and to close the aperture 8, and an engaging section 15 to engage with the upper half 2. The connecting section 13 is formed with a spring retention lug 17 to engage with a shutter opening/closure member introducing groove 16 on the front side 12 of the cartridge main body 4 and to retain the other end of a torsion coil spring 23, as later described, and a locking lug 18 to engage with a shutter locking member 24. In the vicinity of a connection area to the connecting section 13, the shutter section 14 is formed with engaging lugs 21, 22 to engaging with a groove 19 formed in the lower half 3 of the cartridge main body 4. The shutter 12 is attached to the cartridge main body 4 with the shutter section 14 extending over the aperture 8 and clamping the area of the front side 11 of the cartridge main body 4 in cooperation with the connecting section 13 and the engaging section 15. The shutter 12 is mounted on the cartridge main body 4 with the spring retention lug 17 and the locking 18 of the connecting section 13 engaging in the introducing groove 16 and with the engaging lugs 21, 22 of the shutter section 14 engaging in the groove 19. Thus the shutter 12, mounted on the cartridge main body 4, is inhibited from accidental extraction and controlled in its sliding movement by the engaging lugs 21, 22 engaging in the groove 19. The shutter 12, mounted on the cartridge main body 4, is slidable between a position closing the aperture 8 in the cartridge main body 4 and a position opening the aperture 8 as shown by arrows A and B in Figure 2. The area of the cartridge main body 4 in which the shutter 12 is moved is recessed as at 20 to permit flush mounting of the shutter 12 with respect to the surface of the cartridge main body 4. At a corner on the front side 11 of the cartridge main body 4, there is provided the torsion coil spring 23 as biasing means normally to bias the shutter 12 in a direction of closing the aperture 8. The torsion coil spring 23 is mounted within the cartridge main body 4, with its one end retained at the corner of the front side 11 of the cartridge main body 4 and its other end retained by a spring retention recess in the spring retention lug 17 of the shutter 12, to bias the shutter 12 in the direction of closing the aperture 8, as shown by arrow A in Figure 2. At the other corner on the front side 11 of the cartridge main body 4, there is provided the shutter locking member 24 to lock the shutter 12 in a position in which it closes the aperture 8. The shutter locking member 24 comprises an attachment section 25 for attachment to the cartridge main body 4, a resilient flexible section 26 extending from the section 25 and a locking section 28 provided at the distal end of the flexible section 26 and having a recess 27 engaged by the locking lug 18 of the shutter 12. The shutter locking member 24 is mounted within the interior of the cartridge main body 4 by means of the attachment section 25 so that the locking section 28 at the distal end of the flexible section 26 projects into the introducing groove 16. The shutter opening/closure member introducing groove 16 is formed on the front side 11 of the cartridge main body 4 over a sliding range of the shutter 12, beginning at the vicinity of the side 9 of the cartridge main body 4 extending normal to the sliding direction of the shutter 12. Referring to Figure 3, the groove 16 has its end in the vicinity of the side 9 of the cartridge main body 4 as an opening end 16 a into which a shutter opening/closure member of a recording/ reproducing apparatus can be introduced. Referring to Figure 3, the comer towards the side 9 of the cartridge main body 4 provided with the opening end 16 a is formed as an inclined surface 29, while the opposite inner sides towards the opening end 16 a of the groove 16 are formed as inclined guide surfaces 30 a , 30 b to ensure and facilitate insertion and engagement of the shutter opening/closure member into the shutter opening/closure member introducing opening 16. The lower half 3 of the cartridge main body 4 is provided with openings 31, 32 engaged by positioning pins to fix the horizontal loading position of the disc cartridge 1 on loading the disc cartridge 1 into the recording/reproducing apparatus. The openings 31, 32 are provided on both sides in the vicinity of the front side 11 of the cartridge main body 4, as shown in Figure 2. It should be noted that the opening 31 is circular, while the opening 32 is formed as an oblong hole having its longer axis extending in the sliding direction of the shutter 12 to accommodate positioning deviations with respect to the positioning pins. The lower half 3 is also formed with disc type discriminating openings 33, 34 to discriminate the types etc. of the optical disc 5 of the disc cartridge 1. As shown in Figure 2, the openings 33, 34 are formed in the vicinity of the rear side of the cartridge main body 4. With the disc cartridge 1 accommodating the read-only optical disc 5, the signal readout aperture 8 is provided only in the lower half 3. For this reason, the shutter 12 is not extended over the upper half 2 to close an aperture, such that the upper half 2 is exposed to the outside in its entirety. Thus the outer surface of the upper half 2, over which the shutter 12 does not extend, can be utilised as a label surface 35 on which is affixed a label etc. indicating the record contents of the optical disc 5 of the disc cartridge 1. The label surface 35 is formed as a slightly recessed flat surface so that the label bonded thereto does not protrude from the surface of the cartridge main body 4. It suffices if the cartridge main body 4 of the disc cartridge 1 is of a size just large enough to accommodate the optical disc 5 having a diameter R 1 equal to about 64 mm. Thus the cartridge main body 4 has a width W 1 in the sliding direction of the shutter 12 equal to 68 mm, a width W 2 in a direction normal to the sliding direction of the shutter 12 equal to 72 mm, and a thickness D equal to 5 mm. It is noted that the width W 2 is set so as to be larger than the width W 1 in order to reserve a space for accommodating the shutter locking member 24 and the torsion coil spring 23 on the front side 11 of the cartridge main body 4. The recording/reproducing apparatus, employing the above described disc cartridge 1 as a recording medium, may be so constructed as to enable it to be loaded while the shutter closing the aperture 8 with the sliding direction of the shutter 12 as the inserting direction is actuated so as to be opened. That is, by providing a pin-shaped shutter opening/closure member 40 to project on the front side 11 of the cartridge main body 4, which is loaded with the sliding direction of the shutter 12 as the introducing direction, the apparatus may be designed to enable the loading while the shutter 12 is being opened. The operation of loading the disc cartridge into apparatus provided with such shutter opening/closure member 40 is hereinafter explained. The load the disc cartridge to the above mentioned recording/reproducing apparatus, the disc cartridge 1 is inserted with the sliding direction of the shutter 12 as the inserting direction and with the side 9 of the cartridge main body 4 as the inserting side. If the disc cartridge 1 is inserted in this manner, the shutter opening/closure member 40 is engaged in the shutter opening/closure member introducing groove 16 having its opening end 16 a on the side 9 of the cartridge main body 4. If the disc cartridge 1 is inserted further in the direction shown by an arrow C in Figure 4, the shutter opening/ closure member 40 rides on and thrusts the locking section 28 of the locking member 24 protruding into the groove 16 to deflect the resilient section 26 towards the inner side of the cartridge main body 4, disengage the locking lug 18 of the shutter 12 from the engaging recess 27 and unlock the shutter 12. If the disc cartridge 1 is further introduced in the direction shown by arrow C in Figure 5, the shutter opening/closure member 40 engaged in the groove 16 thrusts one side of the shutter 12 to slide the shutter 12 in the direction shown by arrow B in Figure 5 against the bias of the torsion coil spring 23 to open the aperture 8 formed in the cartridge main body 4. When the disc cartridge has been inserted as far as the predetermined loading position in the recording/reproducing apparatus, the shutter 12 has been shifted to a position of fully opening the aperture 8. With the recording/reproducing apparatus employing the above described disc cartridge, having the shutter sliding direction as the inserting direction, as a recording medium, the shutter opening mechanism may be constructed by simply providing the pin-shaped shutter opening/closure member 40 protruding on the front side 11 of the cartridge main body 4 along which slides the shutter 12. Although the above described disc cartridge accommodates a read- or reproduce-only optical disc, the invention is applied to a disc cartridge provided with a magneto-optical disc 50 in which a magnetic thin film is used as a recording layer to enable recorded signals to be erased and re-recorded. Similarly to the optical disc 5, the magneto-optical disc is 64 mm in diameter and able to record musical sound signals for 74 minutes. The magneto-optical disc 50 has its major surface facing an optical pickup device which can irradiate a laser beam on a signal recording layer, and its other major surface facing a magnetic head to supply a magnetic field to the signal recording layer to record desired information signals. Referring to Figures 7 and 8, the cartridge main body 4 of a disc cartridge 100 accommodating the magneto-optical disc 50 is provided not only with an aperture 8 into which the optical pickup device of the illustrative disc cartridge 1 is introduced, but also with an aperture 51 on the upper half 2 into which an above mentioned magnetic head can be introduced. Similarly to the aperture 8, the aperture 51 is rectangular and large enough partially to expose the signal recording surface of the magneto-optical disc 50 to outside between its inner and outer peripheries, and is formed at a position in register with the aperture 8. Since the disc cartridge 100 is provided with apertures 8 and 51 on the opposite sides of the cartridge main body 4, shutter sections 14, 55 for closing the apertures 8, 51, respectively, are provided in a shutter 52, which, for this reason, is in the form of a letter U in which the web is a connecting section 13 and the shutter sections 14, 55 are connected thereto and extend in a facing relation to each other. The shutter 52 is slidably mounted on the cartridge main body 4 to clamp the front side 11 of the cartridge main body 4 with the shutter sections 14, 55 extending over the apertures 8, 51, respectively. With the disc cartridge 100, the area of sliding of the shutter 55 on the upper half 2 to close the aperture 51 is recessed as at 56 to permit flush mounting of the shutter member 55 with respect to the surface of the cartridge main body 4. The engaging lugs 20, 21 engaging in the groove 19 in the cartridge main body 4 slidably to support the shutter 52 in an extraction-free manner on the cartridge main body 4, the spring retention lugs 17 and the locking lug 18 are similar in construction to those of the disc cartridge 1 of the preceding embodiment and therefore are not specifically described herein for simplicity. Similarly, the torsion coil spring 23 normally to bias the shutter 12 in the direction of closing the apertures 8, 51 and the shutter locking member 24 to lock the shutter 12 in the closure position, are similar in construction to those of the preceding cartridge, and hence are not specifically described for simplicity. The cartridge main body 4 of the disc cartridge 100 is of the same size as that of the preceding cartridge and can selectively be loaded into the recording/reproducing apparatus into which the preceding disc cartridge 1 is loaded. Meanwhile, the disc cartridge 100 has a function different from that of the preceding disc cartridge 1, because the magneto-optical disc 50 accommodated therein is designed for re-writing the recorded signals. That is, when the disc cartridge 100 has been loaded in position, the magnetic head needs to be intruded into the cartridge main body 4 by means of the aperture 51. Thus the cartridge main body 4 of the disc cartridge 100 is provided with a notch 57 indicating that the disc accommodated therein is the magneto-optical disc 50 capable of re-writing the signals and enabling intrusion of the magnetic head into the cartridge main body 4. As shown in Figures 7 and 8, the notch 57 is formed on the side 9 in proximity to the front side of the cartridge main body 4. Since the magneto-optical disc 50 for re-recording of information signals is accommodated in the disc cartridge 100, the cartridge main body 4 is provided with a mistaken recording inhibiting member 58. Meanwhile, turning to Figure 9, the mistaken recording inhibiting member 58 is provided outside an area of the cartridge proper 4 occupied by the magneto-optical disc 50, more specifically, at a comer towards the lateral side 10 of the rear side 41 opposite to the front side 11 of the cartridge main body along which is provided the shutter 52. That is, the mistaken recording inhibiting member 58 is provided at a position facing the shutter locking member 24 with the magneto-optical disc 50 in-between. The mistaken recording inhibiting member 58 is moved along the rear side 41 of the cartridge proper 4 to open or close a mistaken recording detecting hole 60 provided at a corner of the rear side of the lower half 3 constituting the major surface of the cartridge proper 4 to indicate whether information signals may or may not be recorded on the magneto-optical disc 50. The mistaken recording inhibiting member 58 is formed from synthetic resin and, as shown in Figure 10 and 11, has a main body 61 to open or close the detecting hole 60 so as to indicate whether recording may or may not be made on the magneto-optical disc 50. An operating lug 62 is formed integrally with the main body 61 so that at least a part of the lug 62 is exposed to outside via an operating window 2 formed by segmenting a part of the rear side 41 of the cartridge main body 4 which is at right angles to the surface of the main body 61 opening or closing the mistaken recording detecting hole 60 and which runs parallel to the direction of opening or closing of the hole 60. Resiliently flexible arms 63, 64 extend from the main body 61 parallel to each other and to the direction of movement of the main member 61 to open or close the hole 60. On the outer sides of the distal ends of the arms 63, 64 are formed engaging means 67, 68 which can selectively engage first mating engaging means 65 a , 65 b and second mating engaging means 66 a , 66 b provided within the cartridge main body 4. Turning again to Figure 4, the cartridge main body 4 is provided with the mistaken recording detecting hole 60 and a guide 70 to guide the mistaken recording inhibiting member 58 parallel to the rear side 41 between a first position of opening the detecting hole 60 and a second position of closing the hole 60 by means of the main body 61. The guide 70 is constituted by a part 41 a of the rear side 41 and a guide wall 71 provided upright on the lower half 3 and extending parallel to the rear side 41. Figures 10 and 11 show that the mistaken recording inhibiting member 58 is mounted so as to be fitted between the part 41 a of the rear side 41 and the guide wall 71, with the operating lug 62 disposed within the operating window 42 formed by segmenting a part of the rear side 41 and with the arms 63, 64 resiliently flexed in a direction away from each other. The mistaken recording inhibiting member 58, thus mounted within the cartridge main body 4, is guided by the guide 70 and can be moved parallel to the rear side 41 in a direction shown by an arrow X in Figure 10 or in a direction shown by an arrow Y in Figure 11, such as by manually thrusting or nipping the lug 62 exposed to outside of the cartridge main body 4 via the operating window 42. On the facing sides of the part 41 a of the rear side 41 and the guide wall 71, there are formed the first mating engaging means 65 a , 65 b as grooves and the second mating engaging means 66 a , 66 b , similarly as grooves, into which the engaging means 67, 68 provided on the mistaken recording inhibiting member 58 are selectively engageable, respectively. As shown in Figure 10, the first mating engaging means 65 a , 65 b are provided at positions engaged by the engaging means 67, 68 at the distal ends of the arms 63, 64 when the mistaken recording inhibiting member 58 is moved to the first position of opening the hole 60 by the main body 61. Similarly, as shown in Figure 11, the second mating engaging means 66 a , 66 b are provided at positions engaged by the engaging means 67, 68 at the distal ends of the arms 63, 64 when the mistaken recording inhibiting member 58 is moved to the second position of closing the hole 60 by the main body 61. By providing the first mating engaging means 65 a , 65 b and the second mating engaging means 66 a , 66 b , selectively engaged by the engaging means 67, 68, the mistaken recording inhibiting member 58 is controlled in its movement, that is, it is moved between and maintained at the first position of opening the hole 60 and the second position of closing the hole 60, so as positively to maintain the opened or closed state of the hole 60. Thus the arms 63, 64, provided with the engaging means 67, 68, engaged with the first mating engaging means 65 a , 65 b or with the second mating engaging means 66 a , 66 b provided at the guide 70, make up controlling means to control the positions of the movement of the mistaken recording inhibiting member 58. Thus, by nipping the operating lug 62 exposed to outside via the operating window 42 formed in the rear side 41 of the cartridge main body 4 facing the front side 12 for shifting the lug in the direction shown by arrow X in Figure 10 or in the direction shown by arrow Y in Figure 11, the hole 60 provided in the major surface of the lower half 3 normal to the rear side 41 is opened or closed by the mistaken recording inhibiting member 58 provided in the cartridge main body 4. With the mistaken recording inhibiting member 58 thus shifted to the first position of opening the hole 60 as shown in Figure 11, recording of information signals on the magneto-optical disc 50 accommodated within the cartridge main body 4 is inhibited. With the member 58 shifted to the second position in which the hole 60 is closed by the main body 62 as shown in figure 10, recording on the magneto-optical disc 50 accommodated in the cartridge main body 4 is enabled. The disc cartridge 100 is also provided with the disc discriminating holes 33, 34 constituting discriminating means to discriminate the types or sorts of the magneto-optical disc 50 accommodated within the cartridge main body 4. The discriminating means are provided to discriminate between the magneto-optical discs of different storage capacities occasionally accommodated within the disc cartridge 100. Referring to Figure 9, the discriminating holes 33, 34 are provided adjacent to the hole 60 along the lateral side 10 of the lower half 3 constituting the lower major surface of the cartridge main body 4. With the above described disc cartridge 100, since the mistaken recording detecting hole 60 and the disc discriminating holes 33, 34 are provided within the lower major surface of the cartridge main body 4, mistaken recording inhibiting means and disc discriminating means may be provided within the major surface of the disc cartridge 100 to contribute to size reduction of the recording and/or reproducing apparatus into which is loaded the disc cartridge 100. Since the mistaken recording inhibiting member 58 can open or close the hole 60 formed in the lower major surface of the cartridge main body 4 by engaging the operating lug 61 disposed in the rear side 41 of the cartridge main body 4, the inhibiting member 58 may be designed as a small-sized member and housed in a small housing space in the small-sized cartridge main body 4. In addition, since the mistaken recording inhibiting member 58 can be moved within the cartridge main body 4 to open or close the hole 60, the recording or non-recording state on the magneto-optical disc 50 may be selected optionally. Although the mistaken recording inhibiting member 58 is arranged in the cartridge main body 4 with the operating lug 62 disposed at the rear side 41 of the cartridge main body 4, it may also be arranged with the operating lug 62 disposed at the lateral side 10 of the cartridge main body 4, in which case the mistaken recording detection hole 60 and the disc discriminating holes 33, 34 are provided side by side along the rear side 41 of the cartridge main body 4. Since only the disposition of the mistaken recording inhibiting member 58 is changed and the arrangement is otherwise the same as that of the preceding disc cartridge 10, detailed description is omitted for simplicity. As shown in Figures 12 and 13, in a disc cartridge 200, the mistaken recording inhibiting means may be constituted by a rectangular mistaken recording detecting hole 160 formed in the lower half 3 constituting the lower major surface of the cartridge main body 4 and a rupturable piece 162 connected to the lower half 3 by a weakened connecting portion 161 and closing the detecting hole 160. When the rupturable piece 162 has not been severed from the lower half 3 but closes the hole 160, recording on the magneto-optical disc 50 is enabled. On the contrary, with the piece 162 being ruptured along the weakened connecting portion 161 as shown in Figure 13 to open the mistaken recording detecting hole 160, recording on the magneto-optical disc 50 is inhibited. Although it not possible with the disc cartridge 200 provided with the rupturable piece 162 as mistaken recording detecting means to select a recording state or a non-recording state optionally, as in the case of a disc cartridge employing the movable mistaken recording inhibiting member 58, the construction of the mistaken recording detecting means may be correspondingly simplified. Similarly to the preceding disc cartridge 1, the disc cartridge 100 is loaded onto a recording/ reproducing apparatus provided with the pin-shaped shutter opening/closure member 40 protruding at the front side 11 of the cartridge main body which is inserted along the sliding direction of the shutter 52. Since the operation of loading the disc cartridge 100 onto the recording/reproducing apparatus is therefore similar to that of loading the preceding disc cartridge 1, detailed description therefore is omitted for clarity. Since the preceding disc cartridge 1 and the disc cartridge 100 of the invention are both approximately square in contour, the direction of inserting it into the recording/ reproducing apparatus may be recognised easily. On the other hand, with the disc cartridge 100 of the present embodiment, since the opening 7 intruded by the disc table and the aperture 8 exposed to the optical pickup device are formed independently of each other, with a web portion in-between, constraints are imposed on the radial range of the magneto-optical disc 50 which is exposed to outside by means of the aperture 8. Thus, with the magneto-optical disc 50 in which a signal recording region extends to close to the centre hole 6 as a result of high density recording, there is a risk that the signal recording region cannot be exposed as far as the inner periphery of the recording region. There is also a risk that the optical pickup device cannot be transferred as far as the inner periphery of the signal recording region so that signal recording/reproduction is rendered impossible. With this in view, a cartridge main body 4 of a disc cartridge 300 shown in Figures 14 and 15 is formed as a rectangle in which a width W 3 in the sliding direction of the shutter 82 is selected to be sufficiently larger than a width W 4 in the direction normal to the sliding direction of the shutter 82 as to facilitate the recognition of the inserting direction into the recording/reproducing apparatus as well as to prevent mistaken insertion. The cartridge main body 4 has the width W 3 in the sliding direction of the shutter 12 of 78 mm, the width W 4 in the direction normal to the sliding direction of the shutter 12 of 72 mm and a thickness D 1 of 5.3 mm. With such increase in width W 3 , an aperture 70 to be entered by the disc table and an aperture 80 to be exposed to the optical pickup device are continuous to each other, as shown in Figure 15. It should be noted that, in order to keep up with an increased size of the cartridge main body 4, the widths of the aperture 80 and an aperture 81 entered by the magnetic head are selected to be wider than those of the disc cartridge 100 of the preceding embodiment. If the aperture 80 is continuous to the aperture 70 to be entered by the disc table, the magneto-optical disc 50 having its signal recording region extending to a position close to the centring hole 6 may be completely exposed to outside up to the inner periphery of the disc. The optical pickup device may be positively transferred to the inner periphery of the signal recording region. Also, by having broader widths of the apertures 80, 81, the optical pickup device and the magnetic head may face each other across the inner and outer peripheries of the magneto-optical disc 50, even if the optical head pickup device and the magnetic head are not reduced in size. With the disc cartridge 300, since the aperture 70 to be entered by the disc table and the aperture 80 exposed to the optical pickup device are continuous to each other, it is necessary to close the aperture 70 simultaneously if it is desired to close the aperture 80 positively. Thus a shutter 82 has a shutter section 85 overlying the aperture 80 which section 85 is of a size large enough to cover the aperture 70 simultaneously. It should be noted that, similarly to the disc cartridge 100, the disc cartridge 300 can be loaded into a recording/reproducing apparatus provided with a pin-shaped shutter opening/closing member 40 projecting towards the front side 11 of the cartridge main body 4 which is inserted along the sliding direction of the shutter 82. Therefore, the operation of loading the disc cartridge 300 into the recording/reproducing apparatus is similar to that of the preceding disc cartridge 100, and hence detailed description thereof is not made herein for clarity. With the above described disc cartridge, the shutter is biased by the shutter resetting spring to a position of closing the aperture which at least partially exposes the optical recording medium along its radius, and is locked by the shutter locking member, the cartridge may be closed hermetically reliably to achieve protection of an optical recording medium, such as an optical disc or a magneto-optical disc, with which it is necessary to prevent the slightest scoring or affixture of the smallest amount of dust and dirt to the signal recording surface if high density recording is to be achieved. When loading the disc cartridge to the recording/reproducing apparatus, the shutter opening/closure member provided on the apparatus is introduced into the opening end of the shutter opening/closure member inserting groove at the side of the cartridge main body lying orthogonally to the sliding direction of the shutter, and is relatively moved along the inserting direction of the cartridge main body to deflect the shutter locking member to unlock the shutter. Thus the shutter is slid against the bias of the shutter resetting spring to open the above mentioned aperture. The shutter opening/closure member of the recording/reproducing apparatus may be simply constituted by a pin-shaped member projecting on the front side of the cartridge main body along which slides the shutter. As a result, the shutter opening/closure mechanism may be simplified in construction to contribute to reduction in size of the recording/reproducing apparatus.

Claims: A magneto-optical disc cartridge comprising a cartridge main body accommodating a disc-shaped magneto-optical recording medium (5) therein and having apertures (8,51;80,81) radially to expose a portion of either side of the magneto-optical recording medium (5) to outside thereby to allow signals to be recorded onto or reproduced from said medium (5); a shutter (12) slidably mounted on the cartridge main body (4) to open and close the apertures (8,51;80,81); a resilient flexible shutter locking member (24) to maintain the shutter (12) in a position closing the apertures (8,51;80,81); a shutter opening/closure member introducing groove (16) having an opening end (16 a ) on a side (9) of the cartridge main body normal to a sliding direction of the shutter, the groove being formed on a front side (11) of the cartridge main body extending parallel to the sliding direction of the shutter; indicating means (33,34) provided in a major surface of the cartridge main body to indicate the storage capacity of the magneto-optical recording medium (5); mistaken recording inhibiting/detecting means (58) provided in the major surface of the cartridge main body to indicate recordability or non-recordability of information signals on the magneto-optical recording medium (5); and a notch (57) for indicating that said disc cartridge is a magneto-optical disc cartridge, said notch being formed on the side (9) of said cartridge in proximity to the front side (11) of the cartridge main body (4). A disc cartridge according to claim 1, wherein the mistaken recording inhibiting member (58) is mounted on the cartridge main body (4) for movement in a direction normal to the direction of thickness of the recording medium (5), and comprises a main body (61) provided at least at one major surface of the cartridge main body and being moveable to open or close a detecting hole (60) indicating recordability or non-recordability of information signals on the recording medium (5); an operating lug integrally formed with the main body (61), the lug being at least partially exposed to the outside via an operating window (42) provided in a side (41) facing the front side (11) of the cartridge main body parallel to the sliding direction of the shutter; and a controlling section to control the movement of the main body (61) between a first position of opening the detecting hole (60) and a second position of closing the detecting hole (60) by the main body (61). A disc cartridge according to claim 1, wherein the mistaken recording inhibiting member (58) comprises a frangible tab provided in a hole (160) formed in at least one major surface of the cartridge main body, the tab being connected to the cartridge main body via a connecting portion (162) and being rupturable from the cartridge main body to indicate whether or not signals may be recorded onto said recording medium (5). A disc cartridge according to any preceding claim, wherein one (80) of said apertures exposes a portion of said medium and a centring hole (6) of said medium.

Inventors: FUJISAWA HIROTOSHI, FUJISAWA, HIROTOSHI, FUJISAWA, HIROTOSHI, C/O PAT. DIV. SONY CORP.
Applicants: SONY CORP, SONY CORPORATION
Application year: 1991
Main classification: G11B23
IPC codes: G11B23