JPH07105124B2 - Disc cartridge - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc cartridge that rotatably accommodates a disc-shaped recording medium and is mounted on a recording / reproducing apparatus together with the disc-shaped recording medium.
In particular, the present invention relates to a disc cartridge suitable for housing a magneto-optical disc. 2. Description of the Related Art Magneto-optical disks to which thermomagnetic effect is applied, which can repeatedly erase and rewrite information signals, are being put to practical use. In this magneto-optical disk, a replica layer having guide grooves for tracking and pre-pit rows such as address pits is formed on one surface of a transparent substrate such as glass,
A perpendicular magnetic recording medium such as a certain amorphous thin film is formed on the surface of the replica layer, and information signals are written and erased by applying the thermomagnetic effect to the perpendicular magnetic recording medium. That is, as shown in FIG. 20 (a), a current I is applied to the electromagnetic coil 50 to apply a magnetic field H in the desired direction of magnetization of the perpendicular magnetic recording medium 51, and as shown in FIG. 20 (b). When the portion of the perpendicular magnetic recording medium 51 to be recorded is irradiated with the laser beam 53 from the laser head 52 to raise the temperature of the portion to near the Curie point, the direction of the magnetization M of the perpendicular magnetic medium 51 is reversed by the thermomagnetic effect. . Since the plane of polarization of the directly polarized laser light is rotated by the direction of the magnetization M when reflected from the magnetic pole (Kerr effect), the rotation of the plane of polarization is detected by the analyzer 54 and the photodetector 55 as shown in FIG. It can be expressed as the intensity of light by passing it. Therefore, as shown in FIG. 20C, if the direction of the magnetization M is reversed in a pattern in the perpendicular magnetic recording medium 51 according to a required information signal, this can be used as a recording bit. On the contrary, if a magnetic field in the opposite direction is applied to the part where the direction of the magnetization M is once reversed and the temperature of the part is increased to near the Kuri point, the direction of the magnetization M of the part is reversed again and the information signal is erased. be able to. In FIG. 21, 5
6 is a laser, 57 and 58 are beam splitters, 59
Indicates a bit signal detection system. As described above, in the magneto-optical disk recording / reproducing apparatus, an electromagnetic coil (magnetic head) 50 for applying a magnetic field H to the perpendicular magnetic recording medium 51 and a laser for heating the perpendicular magnetic recording medium 51. Requires head 52.
The electromagnetic coil 50 and the laser head 52 can be arranged in parallel on one side of the magneto-optical disk, but as shown in FIG.
The laser head 52 faces the lower surface of the magneto-optical disk 60.
Is preferably disposed, and the electromagnetic coil 50 is disposed so as to face the upper surface of the magneto-optical disk 60. By the way, as a disk cartridge for rotatably storing such a magneto-optical disk, a disk cartridge as shown in FIG. 22 is conventionally used (Japanese Patent Laid-Open No. 58-1).
50963). In this figure, 61 is a cartridge case made of synthetic resin, 60 is a magneto-optical disk rotatably accommodated in the cartridge case 61, and 63 is a spindle insertion hole and a head formed in the cartridge case 61 described later in detail. It is a shutter that both opens and closes the insertion hole. As shown in FIGS. 22 and 23, the cartridge case 61 has an upper case 64 formed in a shallow dish shape.
The lower case 65 and the lower case 65 are overlapped with each other, and the magneto-optical disk 60 and other components are housed in the space formed inside. Also, these upper cases 6
4 and the lower case 65 are provided with a circular spindle hole 66 at a substantially central portion corresponding to the rotation center of the magneto-optical disk 60, and a head insertion hole 67 extending in the radial direction of the magneto-optical disk 60. ing. Upper case 6
4 and the front edge of the lower case 65, that is, between the side edge 68 on the insertion side to the recording / reproducing device and the one end 67a of the head insertion hole 67, a connecting portion 69 is formed. The shutter 65 is slidably attached to a groove 70 formed in the connecting portion 69 in a straight line. The conventional disk cartridge described above is
The shutter 63 is opened in association with the insertion operation into the recording / reproducing apparatus, and the spindle provided in the recording / reproducing apparatus is inserted through the spindle insertion hole 66 formed in the upper case 64 and the lower case 65, and the magneto-optical disk 60 is inserted. Is held in a rotatable state. Then, as shown in FIG. 23, the head insertion hole 6 formed in the upper case 64 and the lower case 65.
The electromagnetic coil 50 and the laser head 52 are inserted from the outside of the disk 7 to the positions facing the front and back surfaces of the magneto-optical disk 60, and the information signal can be recorded and reproduced. As described in, for example, Japanese Patent Laid-Open No. 57-113466, a top plate and a bottom plate each having a cutout recess at the center of one end, and an outer shape of a magnetic sheet at the center. A large circular hole slightly larger than the size is formed, and it is composed of three members including an intermediate plate in which a cutout portion is not formed at a position corresponding to the cutout recessed portion. 2. Description of the Related Art There has been conventionally known a magnetic sheet jacket in which a substantially central portion on one end side is formed thin by pasting. In the former of the above-mentioned conventional disk cartridges, since the connecting portion 69 is formed at the side edge portion 68 on the insertion side of the upper case 64 and the lower case 65, the former is not electromagnetic. In order to set the coil 50 and the laser head 52 at predetermined positions with respect to the magneto-optical disk 60, the electromagnetic coil 50 and the laser head 52 can be moved up and down with respect to the magneto-optical disk 60 as shown in FIG. First, as shown in FIG. 24, the cartridge case 61 is inserted between the electromagnetic coil 50 and the laser head 52 in a state where the gap between them is widened.
After the insertion, as shown in FIG. 23, the electromagnetic coil 50 and the laser head 52 have to be moved inwardly to be inserted into the cartridge case 61. For this reason, the carriage mechanism for holding and transferring the electromagnetic coil 50 and the laser head 52 becomes complicated and the recording / reproducing apparatus becomes large, and at the same time, the magneto-optical disk 60 and the electromagnetic coil 50.
Also, there is a problem that the positioning accuracy with the laser head 52 is poor. Further, this disc cartridge has a structure in which the shutter 63 is slidably mounted in the concave groove 70 provided in the upper case 64 and the lower case 65, and therefore, the shutter 63 is opened every time the shutter 63 is opened and closed. There is a problem that the case 64 and the lower case 65 are worn to generate dust, and the dust easily enters the cartridge case 61 through the head insertion hole 67. On the other hand, the latter of the conventional disc cartridges cannot be put to practical use as it is because it is not equipped with a dustproof shutter which covers the window portion when not in use. If a shutter mounting groove is formed on the side of the window opening side of this disc cartridge and the shutter is slidably mounted, a disc cartridge with a shutter can be constructed, but dust is still present. It is not possible to prevent the occurrence of noise and the intrusion into the cartridge case. Also, this disc cartridge is weak in strength because the side of the window opening side is thin.
There is also a problem that unauthorized deformation such as twisting is likely to occur. The present invention has been made in order to solve the deficiency of the prior art, and it is possible to position the magneto-optical disk, the electromagnetic coil and the laser head with high accuracy,
It is also an object of the present invention to provide a disc cartridge excellent in strength. In order to achieve the above object, the present invention provides a cartridge case in which an upper case and a lower case having a spindle insertion hole and a head insertion hole are joined to each other. A disk in which a disk-shaped recording medium is rotatably accommodated, and a shutter for opening and closing the spindle insertion hole and the head insertion hole is slidably provided along a side portion of the cartridge case on the insertion side of the recording / reproducing apparatus. In the cartridge, a head insertion hole whose one end extends to the side portion is formed in the upper case and the lower case, and a thickness smaller than the thickness of the cartridge case is formed in the head insertion hole opening on the joint surface of the upper case and the lower case. -Shaped bridge portion is provided, and the width of the head insertion hole is inserted into the bridge portion through a slider longer than the width of the head insertion hole. A shutter wider than the above is slidably mounted, and the shutter is circumscribed on the outer surfaces of the upper case and the lower case, and when the shutter is opened, the bridge portion is exposed on the side of the head insertion hole. When the shutter is closed, the side of the head insertion hole is reinforced by the bridge, the slider and the shutter. By constructing a bridge portion having high rigidity at both ends of the cartridge case separated by the head insertion hole and the fitting portion of the slider, the rigidity of the outside is increased, and illicit deformation such as twisting occurs. Is prevented. Then, if the diameter or thickness of the bridge portion is smaller than the thickness of the cartridge case and the bridge portion is exposed to the side of the head insertion hole when the shutter is opened, the bridge and the cartridge case are Since the electromagnetic coil and the laser head can be introduced into the head insertion hole through the step between the electromagnetic coil and the laser head, the magnitude of the vertical movement of these electromagnetic coil and laser head can be reduced, or in the best case, the vertical movement can be performed. It is not necessary, the head mechanism of the recording / reproducing apparatus is downsized and simplified, and the positioning accuracy of the disk-shaped recording medium with the electromagnetic coil and the laser head is improved.
Also, attach a slider made of highly slippery material to the bridge,
By attaching the shutter to this slider and sliding the shutter against the cartridge case, it is possible to suppress the generation of dust due to opening and closing of the shutter.
Occurrence of defects due to dust intrusion is reduced. further,
Since both sides of the head insertion hole are reinforced by the slider and the shutter when the shutter is closed, the rigidity of the opening portion of the head insertion hole is also increased by this, and the occurrence of unauthorized deformation such as twisting is prevented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
It will be described based on. First, referring to FIG. 1, an outline of the disc cartridge of the present invention will be described. The disc cartridge comprises a cartridge case 1 made of synthetic resin, a disc-shaped recording medium 2 rotatably housed in the cartridge case 1, It basically comprises a shutter 4 that opens and closes a window hole 3 formed in the cartridge case 1. As shown in FIG. 1, the cartridge case 1 is composed of an upper case 5 and a lower case 6, and these cases 5 and 6 are joined together by using a plurality of joining screws (not shown). Thus, a space for accommodating the disc-shaped recording medium 2 and other required components is formed. In the lower case 6, as shown in FIG.
A window hole 3 penetrating from a substantially central portion corresponding to the rotation center P of the disc-shaped recording medium 2 to a side portion 7 on the insertion side into the recording / reproducing apparatus is provided. On one side of the side portion 7, a slider fitting portion 8 to which the shutter 4 described later in detail is attached is formed. In the width W of the window hole 3, a spindle for rotationally driving the disc-shaped recording medium 2, an electromagnetic coil for recording and reproducing an information signal on the disc-shaped recording medium 2, and a laser head can be inserted. Formed in width. 2 and 3 are provided on the outer peripheral edge of the lower case 6.
As shown in FIG. 2, a joining wall 9 having a constant height is provided upright, and the same height as the joining wall 9 is provided on the circumference around the rotation center P of the disk-shaped recording medium 2. Partition wall 10
Is erected. A first portion, which will be described in detail later, is provided on the joining wall 9 at an opposing portion thereof via the fitting portion 8 of the slider.
Grooves 11 and 11a for fitting after the bridge portion, and recessed portions 12 and 12a for fitting the second bridge portion, which will be described later, in the slightly inner side thereof, and the left side portion. And a recess 13 for operating a light protector, which will be described in detail later, below
A recess 14 for operating a rotary lever, which will be described in detail later, is provided below the right side portion. Further, the partition wall 10
The notch portions 15, 15a, 15b for projecting a disk roller, which will be described in detail later, into the partition wall 10 are formed in the. In FIG. 2, 16 and 16a are second
Screw holes for fixing the bridge portion of the bridge, 17, 17a, 17
b is a concave hole for holding the disc roller, 18, 18
Reference numeral a is a cartridge positioning through hole, 19 is a concave hole for attaching a light protector, 20 is a light protector hole, and 21 is a screw hole for joining the upper case 5 and the lower case 6. Moreover, in FIG. 1 and FIG.
Is a reflector for identifying the A side and B side of the disc cartridge, and 23 is a reflector for identifying the type of the disc-shaped recording medium housed in the disc cartridge. On the other hand, in the upper case 5, each member is in the lower case 5.
Lower case 5 except that it is provided at a symmetrical position to
It has the same shape as. The first bridge portion 24, as shown in FIG.
It is formed by using a metal round bar, and its diameter d is smaller than the thickness S of the cartridge case 1, and preferably,
It is designed to have a thickness equal to or less than the thickness of the disc-shaped recording medium 2. The first bridge portion 24 corresponds to the upper case 5 described above.
The bridge is bridged to the concave grooves 11 and 11a at the joint of the lower case 6. As shown in FIG. 5, the second bridging portion 25 is made of a hard synthetic resin equivalent to the synthetic resin material forming the upper case 5 and the lower case 6, and the thickness thereof is a cartridge. It is designed to be smaller than the thickness S of the case 1 and preferably equal to or less than the thickness of the disc-shaped recording medium 2. The second bridging portion 14 is formed in the recessed portion 12, 1 of the joint portion between the upper case 5 and the lower case 6.
It is bridged to 2a. As shown in FIGS. 6 and 7, the first disc roller 26 of the disc rollers is configured to be engageable with and disengageable from the disc-shaped recording medium 2. That is, the first disk roller 26 is shown in FIG.
As shown in FIG. 7 and FIG. 7, a pivot 28, which is rotatably attached to the tip of a dogleg-shaped rotary lever 27, is provided at a substantially central portion of the rotary lever 26. 5 and the lower case 6 is rotatably supported in a recessed hole 17 provided in the lower case 6. The rotary lever 27 is provided with the concave hole 17
Is wound around a large-diameter pin 29 which is erected in the vicinity of, and the ends thereof are elastically contacted by the small-diameter pin 30 and the rotary lever 27, respectively. It is energized. At one end of the rotary lever 27,
The lower end of the slider 32 slidably fitted to the joining wall 9 is in contact with the joining wall 9. On the other hand, the two recessed holes 17a, 17 located on the diagonal side of the first disk roller 26.
Second and third disc rollers (not shown) are supported on b. In the disc cartridge constructed as described above, in the non-use state, as shown in FIG. 6, the disc-shaped recording medium 2 and the first disc roller 26 elastically biased by the return spring 31 are provided. The movement of the first disc roller 26 is restricted by three-point support with the second and third disc rollers located on the diagonal side of the first disc roller 26 so that the first disc roller 26 does not rotate. However, in the use state, as shown in FIG. 7, the slider 32 is moved in the direction of the arrow A by the engaging claw portion (not shown) in the recording / reproducing apparatus, so that the rotary lever 27 moves the return spring. It rotates clockwise against the elastic force of 31. Therefore, the first disc roller 26 provided on the rotation lever 27 is separated from the peripheral edge of the disc-shaped recording medium 2, and the disc-shaped recording medium 2 can freely rotate. As shown in FIG. 9, the light protector 33 comprises a fan-shaped closing plate 34 capable of closing the light protector hole 20 and a vertically extending support shaft 35 protruding from the substantially central portion thereof. The support shaft 35 is rotatably fitted in the light protector mounting recessed holes 19 formed at the symmetrical positions of the upper case 5 and the lower case 6, and the closing plate 34 is moved to move the light protector hole 20. Is designed to close or open. That is, a thin rod-shaped actuating tool, such as the tip of a ballpoint pen, is inserted through a through hole for operating the light protector formed by a recess 13 formed in a part of the joining wall 9 of the upper case 5 and the lower case 6. As a result, when the tip 34a of the closing plate 34 is pressed and the closing plate 34 is overlapped with the write protector hole 20 as shown in FIG. 10, the detection device provided in the recording / reproducing apparatus is the light protector. It is not inserted into the hole 20 and writing is prohibited. On the contrary, the base end portion 34b of the closing plate 34 is pressed to close the closing plate 34 to the light protector hole 2
When it is removed from the overlapping position of 0, the detection device provided in the recording / reproducing device can be inserted into the write protector hole 20, and the write protection is released. Next, the structure of the shutter 4 will be described.
As shown in FIG. 1, the shutter 4 is made by bending a thin metal plate such as stainless steel into a U-shape, and has an upper piece 4a and a lower piece 4a having a length capable of simultaneously covering the entire window hole 3 of the cartridge case 1. The piece 4b is formed via the connecting piece 4c. In the shutter 4, a slider 36, which will be described in detail later, is attached to the connecting piece 4c, and the slider 36
Is attached to the first reinforcing member 24, the upper piece 4a and the lower piece 4b are superposed on both surfaces of the cartridge case 1, respectively, and then the elongated holding plate is attached to the cartridge case 1 so as to cover the tip portion of the shutter 4. By attaching 37, it is attached to the cartridge case 1. As shown in FIG. 8, the slider 36 can be fitted to the fitting portion 8 formed on the upper case 5 and the lower case 6 with a synthetic resin having excellent lubricity such as nylon or polyacetal. Is formed into a rectangular parallelepiped, and the first reinforcing member 2 is provided at the center in the longitudinal direction.
A through hole 38 through which 4 can be inserted is opened. As shown in FIG. 1, the slider 36 has a through hole 38 formed in the first hole.
By being attached to the reinforcing member 24, the cartridge case 1 is slidably attached along the side portion 7 on the insertion side of the cartridge case 1 into the recording / reproducing apparatus. In FIG. 1, 3
Reference numeral 9 is a return spring that biases the slider 36 toward the center of the cartridge case 1. As the disc-shaped recording medium 2, any known one can be accommodated, but in particular, like a magneto-optical disc, a guide groove for guiding a light beam spot and a prepit such as an address pit. A transparent substrate on which a row is formed and a magnetic recording film deposited on the guide groove and the surface on which the prepit row is formed are included, and the laser head is arranged on the transparent substrate side to obtain a light intensity signal. Is suitable for accommodating a disk-shaped recording medium configured to detect a magnetic signal by arranging a magnetic head on the magnetic recording film side. The disc-shaped recording medium 2 is housed inside the partition wall 10 formed in the lower case 5 and the upper case 6 so as to be rotatable only during use. In the disk cartridge of the first embodiment, the side portion 7 on the insertion side into the recording / reproducing apparatus is opened, and the first portion having a diameter smaller than the thickness of the cartridge case 1 is formed in the opening.
Since the bridge portion 24 and the second bridge portion 25 having a thickness smaller than that of the cartridge case 1 are provided, the first bridge portion 24 and the second bridge portion 25 are bridged. The thickness of the cartridge case 1 is narrower than the side portion 7 side on the insertion side into the recording / reproducing apparatus, and the bridge portion 24,
The electromagnetic coil and the laser head, which are fixed and arranged so as to face each other with a gap wider than the thickness of 25, can be inserted into the cartridge case 1. Therefore, unlike the conventional case, it is not necessary to vertically drive the electromagnetic coil and the laser head with respect to the window hole 3 formed in the cartridge case 1, so that the recording / reproducing apparatus can be downsized and the disc-shaped recording medium 2 can be provided.
It is possible to improve the setting accuracy of the electromagnetic coil and the laser head. In addition, since the spindle for rotating the disc-shaped recording medium and the window for inserting the electromagnetic coil and the laser head for writing and reading the information signal to and from the disc-shaped recording medium 2 are formed in series, the spindle is Since the electromagnetic coil and the laser head can be arranged close to each other, the recording density can be improved. The gist of the present invention is that the side portion 7 on the insertion side into the recording / reproducing apparatus is opened, and a bridge portion having a diameter or a thickness smaller than the thickness of the disc cartridge is bridged to this portion. Therefore, the spindle insertion hole for inserting the spindle and the head insertion hole for inserting the electromagnetic coil and the laser head can be formed specially. Further, in the above embodiment, the case where the magneto-optical disk is used as the disk-shaped recording medium has been described, but the scope of the present invention is not limited to this, and any other disk-shaped optical disk such as an optical disk can be used. It can be applied to a disk cartridge that stores a recording medium. Further, in the above embodiment, the first bridging portion 24 made of a round rod-shaped metal is arranged along the side portion 7 on the insertion side of the cartridge case 1, and the first bridging portion 24 made of a plate-shaped hard synthetic resin is provided inside thereof. Although the embodiment in which the second bridging portion 25 is arranged has been described, the gist of the present invention is not limited to this, and as shown in FIG. It is also possible to dispose the bridge portion 25 of (1) along the side portion 7 on the insertion side of the cartridge case 1 and to dispose the first bridge portion 24 made of a round rod-shaped metal inside thereof. Further, as shown in FIG. 12, a bridge portion 40 in which a round bar-shaped first bridge portion 24 and a flat plate-shaped second bridge portion 25 are integrally formed of hard synthetic resin is used. You can also Further, as shown in FIG. 13, the first bridging portion 24 made of a round rod-shaped metal is arranged along the side portion 7 on the insertion side of the cartridge case 1, and the inside thereof is made of the round rod-shaped metal. The second bridge 25 can also be arranged. Further, the number of bridge portions is not limited to two, and any number of bridge portions can be arranged. FIG. 15 shows an embodiment in which one bridging part 41 is arranged, and the bridging part 41 made of a round bar metal is provided along the side part 7 on the insertion side into the recording / reproducing apparatus.
Is bridged. Instead of the round bar-shaped metal bridge 41, a bridge 41 made of a plate-shaped hard synthetic resin may be used. In these cases, this bridge 41
Then, the shutter 4 is attached via the slider 32. Further, in the above embodiment, the roller 2
Although the case where a simple cylindrical roller is used as 6 has been described, the gist of the present invention is not limited to this, and as shown in FIG. 16, a drum-shaped roller 42 having a central portion with a small diameter is used. It can also be used. In the case of such an embodiment, when not in operation, the disk-shaped recording medium is pressed by the roller 42 and is placed in the small diameter portion 42a of the roller 42, that is, the center portion of the cartridge case 1, and the electromagnetic coil and the laser head are inserted. Can be made easier. In this case, as shown in FIG. 17, when the inclined surface 43 is formed inside the partition wall 19 of the upper case 5 and the case 6, it is sufficient to set one hourglass-shaped roller 42 in any part. In addition, in the first embodiment described above, the case where no member for restricting the motion of the disk-shaped recording medium housed in the cartridge case 1 is provided is described, but the gist of the present invention is not The present invention is not limited to this, and as shown in FIG. 18, a side edge member of the outer peripheral edge of the disk-shaped recording medium 2 is provided on the side of the slider 32 facing the disk cartridge 2 when the shutter 4 is closed. It is also possible to form a disc pressing member 44 facing each other and separated from the outer peripheral edge of the disc-shaped recording medium 2 when the shutter 4 is opened. In the case of such an embodiment, the disc-shaped recording medium 2 is held by the disc pressing member 44 and the lower case 6 when the shutter 4 is closed.
Since the gap between the disk-shaped recording medium 2 and these members 6 and 44 is fixed in a narrow space between them, the impact force applied to the disk-shaped recording medium 2 during handling becomes small, and It is possible to prevent damage. Note that the number of the disc pressing members is not limited to one, and as shown in FIG. 19, two disc pressing members 4 are provided on the side of the slider 32 facing the disc cartridge 2.
It is also possible to form 5,46. In this case, the disc-shaped recording medium 2 has two disc pressing members 45, 46.
Since the disk-shaped recording medium 2 can be arranged in the central portion of the cartridge case 1 since it is held between them,
There is an advantage that the insertion of the electromagnetic coil and the laser head becomes easier. As described above, according to the present invention,
The bridge portion and the shutter enhance the rigidity of the head insertion hole opening of the cartridge case, and prevent the occurrence of unauthorized deformation such as twisting. In addition, it becomes possible to introduce the magnetic recording medium from the step between the cartridge case and the bridge into the electromagnetic coil and the laser head insertion hole, and the head mechanism of the recording / reproducing apparatus can be made smaller and simpler. Further, the positioning accuracy with the laser head can be improved. Furthermore, since the shutter is attached to the cartridge case via the slider, it is possible to reduce the generation of dust accompanying the opening and closing of the shutter and the intrusion of this dust into the head insertion hole.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a disc cartridge according to a first embodiment. FIG. 2 is a plan view of the lower case seen from the inside. 3 is a cross-sectional view taken along the line AA of FIG. FIG. 4 is a perspective view of a first bridge portion. FIG. 5 is a perspective view of a second bridge portion. FIG. 6 is a partial plan view of a lower case. FIG. 7 is a partial plan view of a lower case. FIG. 8 is a perspective view of a slider. FIG. 9 is a perspective view of a light protector. FIG. 10 is a partial plan view of a lower case. FIG. 11 is a partial plan view of the lower case. FIG. 12 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 13 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 14 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 15 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 16 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 17 is a cross-sectional view of a cartridge case according to another embodiment. FIG. 18 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 19 is a partial cross-sectional view of a cartridge case according to another embodiment. FIG. 20 is an explanatory diagram showing a recording principle of a magneto-optical disk. FIG. 21 is an explanatory diagram showing a signal reproduction system of the magneto-optical device. FIG. 22 is an exploded perspective view showing an example of a conventional disc cartridge. FIG. 23 is a partial perspective view showing a mounted state of a head on a disk cartridge. FIG. 24 is a partial perspective view showing a problem of the conventional disc cartridge. [Explanation of Codes] 1 Cartridge case 2 Disc-shaped recording medium 3 Window hole (head insertion hole and spindle insertion hole) 4 Shutter 5 Lower case 6 Upper case 7 Side part on insertion side to recording / reproducing device 8 Slider fitting Section 24 Bridge section 25 Bridge section 32 Slider

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 23/30 B (72) Inventor Annori Kanazawa 1-88, Tora-tora, Ibaraki-shi, Osaka Hitachi Within Maxell Co., Ltd. (72) Inventor Mitsuyoshi Koyama 1-88, Tora-Tora, Ibaraki-shi, Osaka Hitachi Maxell Co., Ltd. (72) Inventor Shin-ichi Abe 2880, Kozu, Odawara-shi, Kanagawa Hitachi Ltd. Odawara Plant (72) Inventor Nobuyuki Fujimoto 2880, Kozu, Odawara-shi, Kanagawa Hitachi Ltd. Odawara factory (56) References JP-A-57-113466 (JP, A) JP-A-61-115284 (JP, A) JP 61-71481 (JP, A) JP 61-11977 (JP, A) Actual opening 59-173178 (JP, U) Actual opening 60-132675 (JP, U)

Claims (1)

(1) A disk-shaped recording medium is rotatably accommodated in a cartridge case formed by joining an upper case and a lower case having a spindle insertion hole and a head insertion hole, and In a disc cartridge provided with a shutter slidably provided along the side portion on the insertion side to a recording / reproducing apparatus for opening and closing the spindle insertion hole and the head insertion hole, one end of the upper case and the lower case is the side side. A head insertion hole extending to the above-mentioned portion, and a bridge portion thinner than the thickness of the cartridge case is provided at the head insertion hole opening portion on the joining surface of the upper case and the lower case. A shutter wider than the width of the head insertion hole is slidably attached via a slider longer than the width of the head insertion hole. Externally contacting the outer surfaces of the upper and lower cases, the bridge portion is exposed on the side of the head insertion hole when the shutter is opened, and the side of the head insertion hole when the shutter is closed. A disk cartridge characterized in that the side portion is reinforced by the bridge portion, the slider and the shutter. (2) In the description of claim 1, the shutter is formed in a U shape composed of an upper piece, a lower piece and a connecting piece, and the connecting piece is arranged outside the bridge portion, A disk cartridge, wherein an upper piece and a lower piece are circumscribed on the shutter adhered portions of the upper case and the lower case. (3) In any one of claims 1 and 2, a disk-shaped recording medium for recording, reproducing, and erasing information by a magnetic head and a laser head is housed in the cartridge case. A disk cartridge characterized by. (4) In any one of claims 1 to 3, the magnetic head and the laser head are arranged to face each other, and the disc-shaped recording medium is inserted between the magnetic head and the laser head. A disk cartridge characterized by being inserted into a recording / reproducing apparatus for recording, reproducing and erasing information. (5) In any one of claims 1 to 4, the disk-shaped recording medium is transparent in which a guide groove for guiding a light beam spot and a prepit row such as an address pit are formed. It is configured to include a substrate and a magnetic recording film adhered to the guide groove and the surface on which the prepit row is formed, and the laser head is arranged on the transparent substrate side to detect an intensity signal of light, and A disk cartridge characterized in that a magnetic head is arranged on the magnetic recording film side so that a magnetic signal can be detected.