Patent Publication Number: US-6667941-B2

Title: Apparatus for loading and ejecting recording medium

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Japanese application serial no. 2000-314230, filed on Oct. 13, 2000, and 2000-314233, filed on Oct. 13, 2000. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a loading apparatus for a recording medium. More specifically, the present invention relates to a loading apparatus capable of loading various types of recording media. In addition, more particularly, the present invention relates to a cartridge loading apparatus wherein the shutter of the cartridge is opened and closed in connection with the eject operation and the loading operation of the cartridge. 
     2. Description of Related Art 
     A conventional recording medium loading apparatus installed in a disc apparatus having exchangeable property for a plurality of disc recording media (referring to compatible disc apparatus, hereinafter) is used as an example for description. For example, a disc apparatus used as a device for reproducing or recording information is built in or externally connected to an electronic apparatus, such as a personal computer or a word processor. The disc apparatus uses the disc-shaped recording medium as its recording medium. In addition, the disc-shaped recording medium is loaded into the disc apparatus using a recording medium loading apparatus and is then reproduced or recorded. 
     On the other hand, a variety of disc recording media are also provided, for example CD (Compact Disc), CD-R (Compact Disc-Recordable), CD-ROM (Compact Disc-Read Only Memory), CD-RW (Compact Disc-Rewritable), DVD-ROM (Digital Versatile Disc-Read Only Memory), DVD-RAM (Digital Versatile Disc-Random Access Memory) are well known. In addition, there are two kinds of recording medium: one is the disc with a diameter of 12 cm, and the other is the disc with a diameter of 8 cm. Moreover, for the DVD-RAM, three kinds can be classified, including wherein the disc is enfolded in a cartridge. 
     As described above, although a variety of disc-shaped recording media is provided, it would be convenient if the reproducing and/or recording process for each disc-shaped recording medium could be performed by one disc apparatus. Therefore, a compatible disc apparatus having the exchangeable property for each disc-shaped recording medium is provided. 
     A variety of the disc-shaped recording media have to be transferred in the main body of the disc apparatus for the compatible disc apparatus. Conventionally, for the recording medium loading apparatus, a tray is used as the transferring device in the main body of the disc apparatus. The tray can be drawn out of the main body of the disc apparatus when the disc-shaped recording medium is loaded or ejected (referring to eject time, hereinafter). In addition, loading recesses are formed on a disc loading surface of the tray for loading the 12 cm disc, 8 cm disc and the disc cartridge, thereby a variety of the disc-shaped recording media can be loaded on the tray. 
     A cartridge is used for loading various types of the disc-shaped recording medium to the main body of the disc apparatus. For example, Japanese Laid Open 10-10620 discloses a cartridge loading apparatus, wherein the top of an arm member installed on the ceiling is engaged with the shutter of the cartridge in the process wherein the tray having the cartridge inserted is moved to the loaded position. The shutter of the cartridge is slid laterally because the arm member is moved in response to the move of the tray and rotated along the guide slit formed on the ceiling. 
     According to the structure above, the cartridge is moved to the loaded position and the shutter of the cartridge is slid to the open position so that the recording or reproducing process can be performed. In addition, in order to maintain the insertion space of the cartridge in the loading apparatus for loading the cartridge enfolding the disc-shaped recording medium, the moving distance of the tray becomes large, and the distance that the arm member slides the cartridge is extended. 
     For the conventional compatible disc apparatus, because the tray is installed for loading the disc-shaped recording media, it is necessary for the tray to be greatly drawn out of the main body of the disc apparatus when the disc-shaped recording media are loaded to or removed from the tray. Therefore, for the conventional compatible disc apparatus, when the disc apparatus is installed, it is necessary to estimate the drawing distance of the tray in advance for setting required space, which becomes a problem in that the installation space becomes large. 
     In addition, a device for loading various types of the disc-shaped recording medium using a clamp lever rather than the tray is provided, by which the disc-shaped recording medium is brought into the main body of the disc apparatus by the clamp lever. 
     In the conventional cartridge loading apparatus, because the arm member for opening/closing the shutter of the cartridge usually slides in a guide slit when the tray is moved from the cartridge insertion position to the cartridge loaded position, sliding resistance is usually acted on the tray. Conventionally, the loading of the tray driving motor for driving the tray becomes large due to the sliding resistance of the arm member, and therefore the tray driving motor cannot be miniaturized. 
     SUMMARY OF THE INVENTION 
     To solve the foregoing problems, it is an object of the invention to provide a recording medium loading apparatus for smoothly loading the disc-shaped recording medium to the carrier, and for stably holding and transferring the disc-shaped recording medium. 
     It is another object of the invention to provide a recording medium loading apparatus to save the installation space and prevent malfunction from occurrence. 
     The present invention provides a recording medium loading apparatus, comprising a carrier for transferring a recording medium between an eject position and a loaded position by moving within a disc apparatus. The carrier comprises a holding device engaged with the carrier for holding the recording medium, so that the holding device is capable of moving with respect to the carrier between a first position protruding from a main body of carrier (a carrier body, hereinafter) in an eject direction of the recording medium and a second position estranging from the first position in an insertion direction of the recording medium, and the holding device is set at the second position when the main body of the carrier is set at the eject position and the holding device is moved from the second position to the first position in a process wherein the carrier body is moved from the eject position to the loaded position. 
     The recording medium is transferred by the carrier. The carrier has a holding device for holding the recording medium, and the holding device is capable of moving between a first position protruding from a carrier body in an eject direction of the recording medium and a second position estranging from the first position in an insertion direction of the recording medium, and the holding device is set at the second position when the carrier body is set at the eject position and the holding device is moved from the second position to the first position in a process wherein the carrier body is moved from the eject position to the loaded position. Namely, the holding device is capable of moving between the first and the second positions within the carrier. 
     The holding device is set at the second position when the carrier body is set at the eject position. Because the second position is estranged from the first position in an insertion direction of the recording medium, the holding device does not protrude from the carrier body in the eject direction of the recording medium. 
     The holding device is moved from the second position to the first position in the process wherein the carrier body is moved from the eject position to the loaded position. The carrier is moved within the main body of the disc apparatus. 
     Therefore, even if the carrier body is set at the eject position, the holding device does not protrude from the main body of the disc apparatus so that the installation space of the disc apparatus can be saved. In addition, in the process wherein the carrier body is moved from the eject position to the loaded position, because the recording medium is held by the holding device, the recording medium can be firmly held and transferred even though the installation space of the disc apparatus is saved. 
     In the apparatus above, when the recording medium has a cartridge, the carrier swingably holds a shutter opening/closing member for opening and closing a shutter installed on the cartridge accompanying with an insertion of the cartridge enfolding the recording medium, and the recording medium loading apparatus further comprises: a cam portion for engaging with the shutter opening/closing member to open/close the shutter of the cartridge in a process that the carrier is moved from the eject position to the loaded position; and a holding member for holding the shutter opening/closing member to displace to a position to open the shutter of the cartridge by engaging with the cam portion. The distance that the shutter opening/closing member is engaged with the cam portion is shortened, and therefore the loading in the process of transferring the cartridge can be reduced. 
     The holding member is installed on the carrier for latching the shutter opening/closing member at a time point when the shutter opening/closing member passes the cam portion in a loading process of the cartridge, and for releasing the latch of the shutter opening/closing member at a time point when the shutter opening/closing member is engaged with the cam portion in an eject process of the cartridge. Therefore, even if there is no engagement with the cam portion, the shutter opening/closing member passing the cam portion can be held at the shutter-opened position. The distance that the shutter opening/closing member is engaged with the cam portion is shortened, and therefore the loading in the process of transferring the cartridge can be reduced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which: 
     FIG. 1 is an explosive diagram of the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 2 is a planar view of the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 3 is a front view of the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIGS. 4A and 4B are side views of the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention, for explaining the operation of the holder; 
     FIG. 5 is a explosive view of the carrier unit in the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIGS. 6A and 6B are perspective views of the clip disc installed on the carrier unit; 
     FIGS. 7A and 7B are diagrams for explaining the operation of the clip disc (I); 
     FIGS. 8A and 8B are diagrams for explaining the operation of the clip disc (II); 
     FIGS. 9A and 9B are diagrams for explaining the operation of the clip disc (III); 
     FIGS. 10A and 10B are diagrams for explaining the disc detecting switch and the disc curve wall formed on the carrier unit  70 . 
     FIGS.  11 A˜ 11 C are diagrams for explaining the operation of the disc lever; 
     FIG. 12 is a diagram of the 8 cm disc inserted to the loading start position in the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 13 is a diagram of the 8 cm disc loaded to the loading finish position in the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 14 is a diagram of the disc apparatus installing a recording medium loading apparatus executing the reproducing/recording process to the 8 cm disc according to one embodiment of the invention; 
     FIG. 15 is a diagram of the 12 cm disc inserted to the loading start position in the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 16 is a diagram of the 12 cm disc loaded to the loading finish position in the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 17 is a diagram of the disc apparatus installing a recording medium loading apparatus executing the reproducing/recording process to the 12 cm disc according to one embodiment of the invention; 
     FIG. 18 is a diagram of the disc cartridge inserted to the loading start position in the disc apparatus installing a recording medium loading apparatus according to one embodiment of the invention; 
     FIG. 19 is a diagram of the disc apparatus installing a recording medium loading apparatus executing the reproducing/recording process to the disc cartridge according to one embodiment of the invention; 
     FIG. 20 is a diagram describing the detail structure of the left rail; 
     FIGS.  21 A˜ 21 F are a diagrams showing the relationship of the position of the carrier unit, the carrier position detecting cam and the operation of the switches SW 1 ˜SW 3 ; 
     FIG. 22 is a block diagram showing the control system of the recording medium loading apparatus according to the embodiment of the invention; 
     FIG. 23 is a flow chart for explaining the transfer control process executed by the control device (I); 
     FIG. 24 is a flow chart for explaining the transfer control process executed by the control device (II); 
     FIG. 25 is a flow chart for explaining the transfer control process executed by the control device (III); and 
     FIG. 26 is a flow chart for explaining the transfer control process executed by the control device (IV). 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     One preferred embodiment of the invention is described in detail accompanying with the drawings. FIGS. 1 to  4 A and  4 B show a disc apparatus  10  installing a recording medium loading apparatus according to one preferred embodiment of the invention. FIG. 1 shows an explosive diagram of the disc apparatus  10 , FIG. 2 shows a planar view of the disc apparatus  10 , FIG. 3 shows a front view of the disc apparatus  10  and FIGS. 4A and 4B show side views of the disc apparatus  10 . 
     The disc apparatus  10  in the embodiment is used for loading, reproducing and/or recording a CD, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM having a diameter of 8 cm (referring to 8 cm disc  11 , hereinafter), a CD, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM having a diameter of 12 cm (referring to 12 cm disc  12 , hereinafter), and a disc cartridge  13  enfolding a DVD-RAM  14  therein, which is a compatible disc apparatus. 
     In addition, for the 8 cm disc  11  and the 12 cm disc  12 , the disc is directly loaded into the disc apparatus  10  without being enfolded within a disc cartridge. In contrast, the DVD-RAM  14  is enfolded within a disc cartridge. 
     The disc apparatus  10  substantially comprises a base  20 , a holder  40 , a carrier unit and a base cover  120 . A turntable  24 , a pick-up  26 , a first disc lever driving cam  28  and a second disc lever driving cam  29  etc., are assembled in a base body of the base  20 . The base body  21  is substantially a plate-shape substrate and has a first opening  22  and a second opening  23  formed thereon. Two guide shafts  27  extending along the Y 1  and Y 2  directions are accommodated on the base body  21  and separated by a predetermined distance. 
     A pick-up  26  is guided by each guide shaft  27  and is movably supported, along the arrow directions of Y 1  and Y 2  as shown, by a pick-up driving mechanism (not shown). The pick-up  26  illuminates laser beams to the disc  11 ,  12  or  14  that is transferred to a position for performing the reproducing and/or recording process (referring to the loaded position, hereinafter), and then receives the reflected beams from the disc. Thereby, the pick-up  26  can perform the reproducing and/or recording process of the disc  11 ,  12  or  14 . 
     The turntable  24  is rotated by a disc motor  25  installed on the base body  21  for a predetermined number of revolutions. As described below, when the disc  11 ,  12  or  14  is moved to the loaded position, the turntable  24  is engaged with center holes  11   a,    12   a,    14   a  of the disc  11 ,  12  or  14  due to the movement of the holder  40  (which will be described in detail below), and then the disc  11 ,  12  or  14  is clamped by the turntable  24  together with the clamp  58 . Therefore, the disc  11 ,  12  or  14  is rotated by the disc motor  25  for the predetermined number of revolutions. 
     In addition, referring to FIG. 3, a holder driving slider  30  is assembled on the back surface of the base body  21  in the vicinity of the second opening  23  (not shown in FIG.  3 ). The holder driving slider  30  is capable of moving in the arrow directions of X 1  and X 2  as shown by a clamping motor  68  (not shown in FIG.  3 ). Referring to FIG. 22, the clamping motor  68  is connected to a control device  150  that is used to control whole operations of the disc apparatus  10  and the recording-medium loading apparatus, thereby the driving control is performed. 
     In addition, a cam plate  31  extending upwards and downwards (the Z 1  and Z 2  directions as shown) is assembled at the predetermined location of the holder driving slider  30 . A pair of tilted cams  32 ,  33  with a long-hole shape is formed on the cam plate  31 . As shown in FIG. 3, each of the tilted cams  32 ,  33  is substantially a Z shape. Therefore, as the holder driving slider  30  is moved by the clamping motor  68  in the arrow directions of X 1  and X 2 , the tilted cams  32 ,  33  are also moved in the X 1  and X 2  directions. 
     Referring to FIGS. 1,  3  and  4 A for details, the first and the second disc lever driving cams  28 ,  29  are protrusions protruded from the base body  21  along the arrow direction of Z 1 . The first and the second disc lever driving cams  28 ,  29  are formed at locations corresponding to accommodating locations of a disc lever, which is described in detail as follows. 
     The holder  40  is installed between the base  20  and the base cover  120 , and is assembled by a right rail  50 , a left rail  51 , a clamper holder  59 , a disc lever  60  and a disc carrier unit  70 . In addition, referring to FIG. 4, the holder  40  is capable of swinging centered on a rotational axis  57  between the base  20  and the base cover  120 , which is described in detail below. Furthermore, the base  20  and the base cover  120  are fixed. 
     The holder  40  comprises a bottom plate  41 , a right sidewall  42  and a left sidewall  43  that are integrally formed by bending and folding a metal plate. There are a first opening  44 , a second opening  45  and a third opening  49  formed on the bottom plate  41  of the holder  40 . 
     The first opening  44  is formed on a location including the installing position of the turntable  24  on the base  20  and the moving position of the pick-up  26 . Therefore, each disc  11 ,  12  or  14  is held on the turntable  24  through the first opening  22  on the base body  21 . In addition, laser beams are transmitted between the pick-up  26  and each disc  11 ,  12  or  14  through the opening  22 . 
     A hanging portion  46  is arranged at an edge of the second opening  45  on the holder  40 . The hanging portion  46  is hung downward from a down side of the bottom plate  41  (along the Z 2  direction in FIG.  3 ). A pair of coupling pins  47 ,  48  is arranged on the hanging portion  46 . The hanging portion  46  protrudes from the back surface of the base  20  through the second opening  23  formed on the base  20  so that the holder  40  is assembled with the base  20 . In addition, as shown in FIG. 3, the coupling pins  47 ,  48  arranged on the hanging portion  46  are respectively engaged with the tilted cams  32 ,  33  on the cam plate  31  formed on the holder driving slider  30 . 
     Therefore, when the clamping motor  68  is driven from the status of the disc apparatus  10  shown in FIG. 3 (also shown in FIG.  4 A), and the holder driving slider  30  is moved along the arrow direction of X 1  in FIG. 3, the coupling pin  47  is moved relatively downward within the tilted cam  32  and the coupling pin  48  is also moved relatively downward within the tilted cam  33 . 
     Accordingly, the holder  40  having the hanging portion  46  installed thereon is swung counterclockwise centered on the rotational axis  57  with respect to FIGS.  4 A/ 4 B. Then, the coupling pins  47 ,  48  reach the lower ends of the tilted cams  32 ,  33 , and the holder  40  is in contact with the base  20  as shown in FIG.  4 B. 
     Moreover, as the clamping motor  68  is driven from the status shown in FIG. 4B (referring to a moving-down position of the holder  40 , hereinafter), and the holder driving slider  30  is moved along the arrow direction of X 2  in FIG. 3, the coupling pins  47 ,  48  are moved relatively upward within the corresponding tilted cams  32 ,  33 . As a result, the holder  40  is swung clockwise centered on the rotational axis  57  with respect to FIGS. 4A and 4B. Then, the coupling pins  47 ,  48  reach the upper ends of the tilted cams  32 ,  33 , and the holder  40  is separated from with the base  20  as shown in FIGS. 3 and 4A (referring to a moving-up position of the holder  40 , hereinafter). 
     On the other hand, the third opening  49  is formed on a position facing the positions of the first and the second disc lever driving cams  28 ,  29  installed on the base  20 . Therefore, when the holder  40  is moved to the lower moving position, the first and the second disc lever driving cams  28 ,  29  protrude from an upper portion of the bottom plate  41  through the third opening  49 . 
     The right sidewall  42  and the left sidewall  43  are respectively formed at the right side and the left side of the bottom plate  41  having the structure mentioned above. The guards  55 ,  56  are respectively formed within a predetermined range over the right and the left sidewalls  42 ,  43  by folding and bending sidewalls  42 ,  43  inwards by right angles. Therefore, the two side portions of the holder  40  are substantially a U shape in a front view shown in FIG.  3 . 
     Rails  50 ,  51  are respectively arranged on each sidewalls  42 ,  43  having guards  55 ,  56 . More specifically, the right rail is fixed on the right sidewall  42  and the left rail  51  is fixed on the left sidewall  43 . Each of the rails  50 ,  51 , which can be made of resin, is arranged along the two sidewalls  42 ,  43  of the holder  40 , extending long in both arrow directions of Y 1  and Y 2  as shown in FIG.  1 . 
     Referring to FIG. 3 the cross-sections of each of the rails  50 ,  51  is substantially a U shape. Using the rails  50 ,  51  as guides, a carrier unit  70 , which is described in detail below, can be moved along the arrow directions of Y 1  and Y 2  as shown. Referring to FIG. 20, a lock gear  52  and a carrier position detecting cam  140  are further formed on an inner wall of the left rail  51 . 
     In FIG. 1, the lock gear  52  is formed within a moving range of the carrier unit  70 . In addition, the carrier position detecting cam  140  is a cam with a two-piece structure, formed by an upper cam  141  and a lower cam  142 . FIGS.  21 A˜ 21 F illustrate status separating the upper cam  141  and the lower cam  142  that construct the carrier position detecting cam  140 . 
     Referring to FIGS.  21 A˜ 21 F, the upper cam  141  is formed having cam shapes, including a first protrusion  141   a,  a first recess  141   b,  a second protrusion  141   c,  a second recess  141   d  and a third recess  141   e  subsequently formed thereon from the left side in FIG. 21A to the Y 1  direction. Also, the lower cam  142  is formed having cam shapes, including a protrusion  142   a  and a recess  142   b  subsequently formed thereon from the left side in FIG. 21A to the Y 1  direction. The cam shape for each of the cams  141 ,  142  is set to correspond to a predetermined stop position of the carrier unit  70 . 
     Referring to FIG. 1, a cartridge lever retroceding opening  53  is formed on the right rail  50  to penetrate therethrough together with the right sidewall  42  in the arrow directions of X 1  and X 2 , and also a disc lever opening  67  is formed on the left rail  51  to penetrate therethrough together with the left sidewall  43  in the arrow X 1  and X 2  directions. Moreover, the rails  50 ,  51  are firmly fixed on the holder  40  without displacement respective to the holder  40 . 
     As shown in FIG. 1, the disc lever  60  comprises a lever body  61 , a rotational axis  62 , an engaging jaw  63  and an engaging member  66 . The rotational axis  62  is installed in a standing manner at an end of the lever body  61  in the Y 1  direction shown in FIG. 1, and the rotational axis  62  is rotatably supported to a bearing  64  formed on the left sidewall  43  of the holder  40 . As described above, because the disc lever opening  67  is formed on the left rail  51  and the left sidewall  43 , the disc lever  60  can be freely rotated within the disc lever opening  67  centered on the rotational axis  62 . 
     The lever body  61  is substantially a plate shape and placed on the bottom plate  41  when the lever body  61  is attached to the holder  40 . Accordingly, the lever body  61  is slid on the bottom plate  41  by means of the lever body  61  being rotated. Furthermore, the engaging member  66  is formed at a predetermined position of the lever body  61 , and engaging member  66  is selectively engaged with the first or the second disc lever driving cam  28 ,  29  installed on the base  20  when the holder  40  is moved to the moving-down position. 
     The engaging jaw  63  is a pair of jaw plates arranged up and down, and is installed in a standing manner at another end of the lever body  61  in the Y 2  direction shown in FIG.  1 . The engaging jaw  63  engages with a rear portion of the disc  11  or  12  with respect to an insertion direction when the 8 cm disc or 12 cm disc is inserted and transferred in the disc apparatus  10 , thereby the engaging jaw  63  achieves the function of holding the disc  11  or  12 . 
     Referring to FIG. 2, the disc lever  60 , having a structure as described above, is connected to an actuating spring  65 . An end of the disc lever actuating spring  65  in the arrow direction of Y 1  is connected to the holder  40 , and another end in the arrow direction of Y 2  is connected to the disc lever  60 . From planar view, the disc lever  60  is rotated by the disc lever actuating spring  65 , counterclockwise centered on the rotational axis  62 . 
     On the other hand, two side portions of the clamper holder  59  are installed on the top portion of the holder by screwing screws to the guards  55 ,  56 . A clamper  58  is installed on the central portion of the clamp holder  59 . The installation position of the clamper  58  corresponds to the installation position of the turntable  24  installed on the base  20 . 
     On the other hand, in the situation that the holder  40  is moved to the moving-up position shown in FIG. 4A, the clamper  58  is separated from the turntable  24 , allowing each disc  11 ,  12  or disc cartridge  13  to be placed into the holder  40 . As the each disc  11 ,  12  or disc cartridge  13  is transferred into the holder  40  and the holder  40  is moved to the moving-down shown in FIG. 4B, the clamper is relatively close to the turntable  24 . 
     Next, the disc  11 ,  12  or the disc cartridge  13  inserted to the insertion opening  133  is transferred within the disc apparatus  10  by the carrier unit  70 . At a time point that the disc transfer is finished, the clamper  58  is in contact with the turntable  24 , and each of the discs  11 ,  12  or  14  is clamped between the clamper  58  and the turntable  24 . At this time, the clamper  58  provides a clamp magnet and the turntable  24  provides a clamp yoke. Accordingly, each disc  11 ,  12  or  14  is firmly clamped between the clamper  58  and the turntable  24  by means of a magnetic force provided by the clamp magnet and absorption from the clamp yoke. 
     Next, FIGS. 1 to  4  together with FIG. 5 are used for describing the carrier unit  70 . The carrier unit  70  forms a structure for holding each disc  11 ,  12  and disc cartridge  13 , which is movably arranged on the holder  40  in the arrow directions of Y 1  and Y 2 . Therefore, each disc  11 ,  12  and the disc cartridge  13  is transferred in the insertion direction by means of the carrier unit  70  moving in the arrow direction of Y 1  in a status holding the disc  11 ,  12  or the disc cartridge  13 . In addition, each disc  11 ,  12  and the disc cartridge  13  is transferred in the eject direction by means of the carrier unit  70  moving in the arrow direction of Y 2  in a status holding the disc  11 ,  12  or the disc cartridge  13 . 
     As shown in FIG. 5, the carrier unit  70  is formed by an upper half portion  71 , a right lower half portion  72 , a left lower half portion  73 , clip disc  74 - 1 ˜ 74 - 4 , cartridge lever  77  and a shutter lever  78  etc. The half portions  71 ˜ 73  are made of resin and cooperate with one another to form a carrier body. The upper half portion  71  is formed by connecting a right portion  71   a  and a left portion  71   b  with a connecting portion  71   c.  An assembling recess  91  is formed on the right portion  71   a  for installing the first clip disc  74 - 1  and a plate spring  79 , and an assembling recess  90  is formed on the left portion  71   b  for installing the third clip disc  74 - 3 . 
     A cartridge lever guiding groove  103 , extending in the arrow directions of Y 1  and Y 2 , is formed in the vicinity of the right side of the right portion  71   a.  An axis  105  of the cartridge lever  77  is movably engaged with the cartridge lever guiding groove  103 . The cartridge lever  77  is used when the disc cartridge  13  is transferred, and is described in detail below. 
     In addition, an axis hole  117  is formed on the right portion  71   a,  and the shutter lever  78  is assembled through the axis hole  117 . The shutter lever functions to open and close a shutter  150  installed on the disc cartridge  13  when the disc cartridge  13  is inserted to the disc apparatus  10 . 
     The shutter lever  78  has an axis portion  110  protruded downward in the vicinity of an end of a plate-shaped lever body  109 , and the shutter lever  78  is assembled onto the upper half portion  71  by means of the axis portion  110  being rotatably inserted into the axis hole  117 . In addition, as shown in FIG. 2, a shutter lever actuating spring  115  is installed at a position such that the axis portion  110  is inserted into the axis hole  117 . 
     One end of the shutter lever actuating spring  115  is engaged with a spring connecting portion  114  formed on the end of the lever body  109 , and another end is engaged with a predetermined position of the right portion  71   a.  Accordingly, the shutter lever  78  is rotated counterclockwise with respect to FIG. 2 centered on the axis portion  110  by the shutter lever actuating spring  115 . 
     In addition, a long hole  112 , extending along longitudinal direction of the lever body  109 , is formed in the vicinity of the other end of the lever body  109 , and a shutter driving pin  113  is movably assembled in the long hole  112 . As shown in FIG. 3, the shutter driving pin  113  is protruded downward from the lever body  109  for engaging with the shutter  15  installed on the disc cartridge  13  (shown in FIGS. 18,  19 ). 
     The shutter driving pin  113  is also engaged with a slit  126  formed on the base cover  120 . Accordingly, when the disc cartridge  13  is inserted to or ejected from the disc apparatus  10 , the shutter  15  is opened and closed because the shutter driving pin  113  is restrictively moved within the positions of the long hole  112  and the slit  126  as the shutter lever  78  is rotated. 
     Furthermore, an engaging hole  111  is formed at a center position of the lever body  109 . Referring to FIGS. 13 to  19 , the engaging hole  111  is engaged with the plate spring  79  installed on the upper half portion  71  at a time point that the shutter  15  is rotated to be completely opened when the disc cartridge  13  is inserted. More specifically, the engaging hole  111  is engaged with a protruded portion  116  formed on the plate spring  79 . Therefore, after the shutter  15  is completely opened, the shutter lever  78  can prevent the shutter  15  from being rotated to its closed direction due to the actuating force of the shutter lever actuating spring  115  and the engaging force of the plate spring  79 , and therefore the shutter  15  maintains an opened state. 
     Referring to FIG. 18, due to the move toward the ejecting direction (the arrow direction of Y 2  as shown) of the cartridge unit  70 , the shutter driving pin  113  is engaged with the slit  126  again when the disc cartridge  13  is ejected from the disc apparatus  10 . Accordingly, the shutter driving pin  113  begins to move restrictively within the positions of the long hole  112  and the slit  126  by the ejecting operation of the disc cartridge  13 , and thereby the engagement between the engaging hole  111  and the plate spring  79  is released. Then, the shutter lever  78  is rotated clockwise and therefore the shutter  15  is closed. 
     On the other hand, referring to FIG. 5, the lower right half portion  72  is assembled under the right portion  71   a  forming the upper half portion  71 . A cartridge lever guide groove  104 , extending in the arrow directions of Y 1  and Y 2 , is formed in vicinity of the right side of the right lower half portion  72 . An axis portion  105  (not shown) located under the cartridge lever  77  is movably engaged with the cartridge lever guide groove  104 . 
     Accordingly, the axis portion  105  protruded above and below the cartridge lever  77  is movably and rotatably engaged with the cartridge lever guide grooves  103 ,  104  under the condition that the right lower half portion  72  is fixed onto the upper half portion  71 . Namely, the cartridge lever  77  is capable of moving along the insertion/remove directions (the arrow directions of Y 1  and Y 2  in FIG. 5) of each disc  11 ,  12  or  14  with spaces enclosed by the cartridge lever guide grooves  103 ,  104 , and the cartridge lever  77  is capable of rotating centered on the axis portion  105 . 
     A cartridge lever actuating spring  108  is installed on the cartridge lever  77 . One end of the cartridge lever actuating spring  108  is connected to a spring connecting portion  107  formed on the cartridge lever  77 , and the other end is connected to a predetermined position of the right lower half portion  72 . Therefore, an resilient force is acted on the cartridge lever  77  within the cartridge lever guide grooves  103 ,  104 . Namely, the cartridge lever  77  is rotated clockwise centered on the axis portion  105  with respect to the drawing of FIG.  2 . 
     Furthermore, a disc facing surface  93  is formed on the right lower half portion  72 , and an 8 cm-disc curve wall  94  and a 12 cm-disc curve wall  95  are provided in a standing manner on the outer circumference of the disc facing surface  93 . The 8 cm-disc curve wall  94  has a curvature radius of 4 cm, and the 12 cm-disc curve wall  95  has a curvature radius of 6 cm. 
     When the 8 cm disc  11  is inserted to the carrier unit  70 , a front end in the insertion direction of the 8 cm disc  11  is in contact with the curve wall  94  for the 8 cm disc, and additionally a front end in the insertion direction of the 12 cm disc  12  is contact with the 12 cm-disc curve wall  95  when the 12 cm disc  12  is loaded into the carrier unit  70 . As described above, the disc curve walls  94 ,  95  have curvature radii respectively corresponding to the radii of the loaded discs  11 ,  12 , and the 8 cm-disc curve wall  94  with a small curvature radius is arranged in the arrow direction of Y 1  with respect to the 12 cm-disc curve wall  95  with a large curvature radius. More over, the 8 cm-disc curve wall  94  and the 12 cm-disc curve wall  95  with configurations mentioned above are also installed on the right portion  71   a,  the left portion  71   b  and the left lower half portion  73  (disc curve walls  94 ,  95  formed on the right portion  71   a  and the left portion  71   b  are not shown in FIG.  5 ). 
     Accordingly, the 8 cm disc  11  is in contact with the 8 cm-disc curve wall  94  when the 8 cm disc  11  is inserted to the carrier unit  70 . Referring to FIGS. 10A and 10B, as the 8 cm disc  11  is just pushed to contact with the 8 cm-disc curve wall  94 , the position of the 8 cm disc  11  with respect to the carrier unit  70  can be determined because the shape of the 8 cm-disc curve wall  94  corresponds to the outer circumference of the 8 cm disc  11 . 
     Similarly, when the 12 cm disc  12  is inserted to the carrier unit  70 , the 12 cm disc  12  is contact with the 12 cm-disc curve wall  95  rather than the 8 cm-disc curve wall  94 . Accordingly, as the 12 cm disc  12  is just pushed to contact with the 12 cm-disc curve wall  95 , the position of the 12 cm disc  12  with respect to the carrier unit  70  can be determined (referring to FIGS.  10 A and  10 B). 
     The disc facing surface  93  is a tilt surface tilted from the disc curve walls  94 ,  95  toward the arrow direction of Y 2  in FIG.  5 . Therefore, each of the discs  11  and  12  is guided by the disc facing surface  93  and pushed to contact with the disc curve walls  94 ,  95  when the discs  11  and  12  are loaded into the carrier unit  70 . Accordingly, the position determination process of the discs  11  and  12  with respect to the carrier unit  70  can be easily determined. 
     Furthermore, referring to FIGS. 10A to  10 B, a front end portion of the disc cartridge  13  is in contact with a front surface  89  of the carrier unit  70  when the disc cartridge  13  is inserted into the apparatus  10 . Therefore, due to the contact, the position determination of the disc cartridge  13  with respect to the carrier unit  70  can be made. In addition, a disc cartridge detecting switch  98  is installed on the right lower half portion  72 , and has a contact portion  99  protruded from the front surface  89  of the carrier unit  70  (referring to FIG.  10 A). Therefore, the inserting process until the disc cartridge  13  is in contact with carrier unit  70  can be detected by the output of the disc cartridge detecting switch  98 . Moreover, the disc cartridge detecting switch  98  is further connected to the control device  150  (referring to FIG.  22 ). 
     Referring to FIG. 5, a loading motor  100  and a gear group  101  are installed on the left lower half portion  73 . The loading motor  100  drives the gear group  101  by meshing to the gear group  101 . In addition, a gear  102  located at the outmost portion of the gear group  101  protrudes outward from the left lower half portion  73 . The gear  102  is meshed to the lock gear  52  formed on the left rail  51  assembled on the holder  40  in the status wherein the carrier unit  70  is assembled to the holder  40 . Additionally, a first, a second and a third position detecting switches (SW 1 , SW 2  and SW 3 , hereinafter) are installed on the left lower half portion  73 . 
     Accordingly, by means of the loading motor  100  being driven and the gear  102  meshed to the lock gear  52  being rotated via the gear group  101 , the carrier unit  70  is selectively moved in the arrow direction of Y 1  (the insertion direction) or in the arrow direction of Y 2  (the ejecting direction) within the holder  40 . Additionally, as the carrier unit  70  holds the disc  11 ,  12  or the disc cartridge  13  and the loading motor  100  is driven, the disc  11 ,  12  or the disc cartridge  13  together with the carrier unit  70  are transferred in the arrow direction of Y 1  (the insertion direction) or in the arrow direction of Y 2  (the ejecting direction). Moreover, the loading motor  100  is connected to the control device  150  (referring to FIG. 22) for performing the driving control. 
     As described above, the 8 cm-disc curve wall  94  and the 12 cm-disc curve wall  95  are also installed on the left lower half portion  73 . As shown in FIGS. 10A and 10B, an 8 cm-disc detecting switch  96  and a 12 cm-disc detecting switch  97  are respectively installed on the 8 cm-disc curve wall  94  and the 12 cm-disc curve wall  95 . Both of the disc detecting switches  96 ,  97  are also connected to the control device  150 . 
     The 8 cm-disc detecting switch  96  outputs a signal in response to the 8 cm disc  11  being inserted to a predetermined loaded position (the position in contact with the 8 cm disc curve wall  94 ) in the carrier unit  70 , and the 12 cm-disc detecting switch  97  outputs a signal when the 12 cm disc  12  is inserted to a predetermined loaded position (the position in contact with the 12 cm-disc curve wall  95 ) in the carrier unit  70 . Therefore, from the output signal out of the disc detecting switches  96 ,  97 , the control device  150  can detect that each of the discs  11  and  12  is loaded to the corresponding predetermined loaded position in the carrier unit  70 . 
     Referring to FIG. 22, each of the switches SW 1 ˜SW 3  can be ON/OFF by pressing a switch knob, and is respectively connected to the control device  150 . Of the three switches SW 1 ˜SW 3 , the heights of the switches SW 1  and SW 3  are a little higher than that of the switch SW 2  arranged in middle of the switches SW 1  and SW 3 . In addition, the switch SW 3  is engaged with the upper cam  141  of the carrier position detecting cam  140  formed on the left rail  51  and the switch SW 2  is engaged with the lower cam  142  when the carrier unit  70  is assembled to the holder  40 . Accordingly, the switches SW 1 , SW 3  are ON/OFF corresponding to the cam shapes of the upper cam  141  when the carrier unit  70  is moved, and the switch SW 2  is ON/OFF corresponding to the cam shapes of the lower cam  142  when the carrier unit  70  is moved. 
     Next, the first to the fourth clip disc  74 - 1 ˜ 74 - 4  assembled on the carrier unit  70  are described as follows. Furthermore, in the embodiment of the present invention, the four clip discs  74 - 1 ˜ 74 - 4  are assembled, but they are the same structure. Therefore, in the following description, all of the four clip discs  74 - 1 ˜ 74 - 4  are termed clip discs  74  if no specified situation is pointed out. 
     FIG. 6 shows an enlarged structure for each clip disc  74 . The clip disc  74  is made of resilient resin material and consists of a pair of tongue pieces  86 . A through hole  85   a  for screwing a screw (not shown) therethrough is formed on a fixing portion  85  of each clip disc  74 . The screws (not shown) are screwed through the through holes  85  such that the right portion  71   a,  the left portion  71   b,  the right lower half portion  72  and the left lower half portion  73  are all screwed together. Thereby, each of the clip discs  74 - 1 ˜ 74 - 4  are fixed on the carrier unit  70 . 
     The tongue pieces  86  are tilted and extended in front of the fixing porting  85  by bending and folding two side portions of the fixing porting  85 . Therefore, the clip disc  74  is substantially a V shape from its side view. Furthermore, a touch portion  88  is protruded from a front end of each tongue piece  86 . 
     As shown in FIG. 5, the first clip disc  74 - 1  is installed on the assembling recess  91  from the top of the right portion  71   a.  At this time, the tongue pieces  86  of the first clip disc  74 - 1  are located at a lower position. In addition, an opening  92  is formed on a position of the assembling recess  91 , which faces the tongue piece  86 , thereby the tongue piece  86  is protruded to the disc facing surface  93  through the opening  92 . 
     The second clip disc  74 - 2  is installed on the assembling recess (not shown) formed on the right lower half portion  72  from the bottom. At this time, the tongue pieces  86  of the second clip disc  74 - 2  are located at an upper position. In addition, an opening  92  is formed on a position of the assembling recess, which faces the tongue piece  86 , thereby the tongue piece  86  is protruded to the disc facing surface  93  through the opening  92 . 
     At this time, the assembling positions of the first clip disc  74 - 1  and the second clip disc  74 - 2  are set in an opposite manner. More specifically, referring to FIG. 7A, the first clip disc  74 - 1  and the second clip disc  74 - 2  are arranged such that the corresponding tongue pieces  86  resist each other, and the contact portions  88  formed on the front ends of the tongue pieces  86  utilize the actuating force of the tongue pieces  86  to contact each other. At this time, the contact portions  88  of tongue pieces  86  contact by means of gradually approaching to the insertion direction (the arrow direction of Y 1 ) of the disc  11 ,  12 . 
     According to the structure above, when the 8 cm disc  11  or the 12 cm disc  12  is inserted to the carrier unit  70 , the disc  11  or  12  is inserted between the first clip disc  74 - 1  and the second clip disc  74 - 2 . Referring to FIG. 7B, the right front end in the insertion direction of the discs  11 ,  12  is clamped between the touch portion  88  of the first clip disc  74 - 1  and the touch portion  88  of the second clip disc  74 - 2 . Thereby, the discs  11 ,  12  can be firmly held by the first clip disc  74 - 1  and the second clip disc  74 - 2 . 
     The third clip disc  74 - 3  is installed on the assembling recess  90  from the top of the left portion  71   b.  At this time, the tongue pieces  86  of the third clip disc  74 - 3  are located at a lower position. In addition, an opening  92  is formed on a position of the assembling recess  90 , which faces the tongue piece  86 , thereby the tongue piece  86  is protruded to the disc facing surface  93  of the left portion  71   b  through the opening  92 . 
     The fourth clip disc  74 - 4  is installed on the assembling recess (not shown) formed on the left lower half portion  73  from the bottom. At this time, the tongue pieces  86  of the fourth clip disc  74 - 4  are located at an upper position. In addition, an opening  92  is formed on a position of the assembling recess, which faces the tongue piece  86 , thereby the tongue piece  86  is protruded to the disc facing surface  93  on the left lower half portion  73  through the opening  92 . 
     At this time, the assembling positions of the third clip disc  74 - 3  and the fourth clip disc  74 - 4  are set in an opposite manner, which is similar to the opposite arrangement of the first clip disc  74 - 1  and the second clip disc  74 - 2 . In the opposite status, the contact portions  88  formed on the tongue pieces  86  of the third clip disc  74 - 3  and the fourth clip disc  74 - 4  utilize the actuating force of the tongue pieces  86  to contact each other. At this time, the contact portions  88  of tongue pieces  86  contact by means of gradually approaching to the insertion direction (the arrow direction of Y 1 ) of the disc  11 ,  12 . 
     According to the structure above, when the 8 cm disc  11  or the 12 cm disc  12  is inserted to the carrier unit  70 , the disc  11  or  12  is inserted between the third clip disc  74 - 3  and the fourth clip disc  74 - 4 . Then, as shown in FIG. 7B, the left front end in the insertion direction of the discs  11 ,  12  is clamped between the touch portion  88  of the third clip disc  74 - 3  and the touch portion  88  of the fourth clip disc  74 - 4 . Thereby, the discs  11 ,  12  can be firmly held by the third clip disc  74 - 3  and the fourth clip disc  74 - 4 . 
     Now, focusing on and describing the assembling positions of the tongue pieces  86  formed on each clip disc  74  ( 74 - 1 ,  74 - 2 ,  74 - 3 ,  74 - 4 ) accompanying with FIGS. 10A and 10B, as described above, a pair of the tongue pieces  86  is respectively formed on the clip disc  74 , in the status wherein the clip disc  74  is assembled to the carrier unit  70 , and the assembling position of one of the tongue pieces  86  is set opposite to the 8 cm-disc curve wall  94  (this tongue piece  86  refers to a tongue piece  86  for the 8 cm-disc tongue piece  86 - 8  in a specified case, hereinafter). Additionally, the assembling position of another of the tongue pieces  86  is set opposite to the 12 cm-disc curve wall  95  (this tongue piece  86  refers to a tongue piece  86  for the 12 cm-disc tongue piece  86 - 12  in a specified case, hereinafter). 
     Accordingly, in the case of the 8 cm disc  11  being inserted to the carrier unit  70 , the 8 cm disc  11  is held by the 8 cm-disc tongue piece  86 - 8 , and in the case of the 12 cm disc  12  is inserted to the carrier unit  70 , the 12 cm disc  12  is held by the 12 cm-disc tongue piece  86 - 12 . As the carrier unit  70  is moved in the status wherein the discs  11 ,  12  are respectively held by the 8 cm-disc tongue piece  86 - 8  and the 12 cm-disc tongue piece  86 - 12 , each of the discs  11 ,  12  is transferred between the position for inserting/removing (referring to eject position, hereinafter) and the loaded position with respect to the carrier unit  70 . 
     When the discs  11 ,  12  are transferred, the outer circumferences (more specially, the front edge in the insertion direction) of the discs  11 ,  12  are held by the 8 cm-disc tongue piece  86 - 8  and the 12 cm-disc tongue piece  86 - 12 . An area not used for performing a recording or reproducing process is formed with a predetermined range at the outer circumference of each disc  11 ,  12 , and the contact portions  88  of the disc tongue pieces  86 - 8 ,  86 - 12  are in contact with the area not used for performing the recording or reproducing process. Therefore, this prevents the areas for performing the recording/reproducing process of the discs  11 ,  12  from damage when the discs  11 ,  12  are transferred. 
     Moreover, as described above, because the discs  11 ,  12  are held by the disc tongue pieces  86 - 8 ,  86 - 12  when the discs  11 ,  12  are transferred, relative displacements between the disc tongue pieces  86 - 8 ,  86 - 12  and the discs  11 ,  12  don&#39;t occur, thereby a highly accurate transfer process can be performed. 
     However, if the operator of the disc apparatus  10  still holds the disc  11 ,  12  after the disc  11 ,  12  is inserted and then held by the carrier unit  70 , the drawing force is acted on the disc  11 ,  12 . If the operator processes a wrong operation, the disc  11 ,  12  is promptly detached from the carrier unit  70 , and the clamp operation may fail. Therefore, even if the drawing force to some degree is acted on the disc  11 ,  12  after insertion, that the disc  11 ,  12  is not promptly detached from the clip discs  74  is demanded. 
     In the embodiment, for solving the problem above, the tongue pieces  86  installed on the clip disc  74  gradually close in the insertion direction (the Y 1  arrow direction), and then clamp the outer circumferences of the discs  11 ,  12 . Therefore, in the holding status shown in FIG.  7 B and in the case that a force in the drawing direction (the drawing force) from the carrier unit  70  is applied to the discs  11 ,  12 , a force in the B arrow direction is created to act on the tongue pieces  86  due to the drawing force. Accordingly, after the carrier unit  70  (the clip disc  74 ) holds the discs  11 ,  12 , even though the drawing force is applied to the discs  11 ,  12  by mistake, the discs  11 ,  12  can be prevented from detaching from the carrier unit  70  (the clip disc  74 ). 
     Moreover, according to the embodiment of the invention, the discs  11 ,  12  are clamped by a pair of the clip discs arranged up and down (the first clip disc  74 - 1  and the second clip disc  74 - 2 , the third clip disc  74 - 3  and the fourth clip disc  74 - 4 ). However, as shown in FIGS. 8A and 8B, each of the discs  11 ,  12  can also be clamped by only one clip disc  74 . In such a case, it is advantageous that the carrier unit  70  can become more compact and smaller because the number of the clip discs is reduced and assembling space is saved 
     In the embodiment of the invention, the disc detecting switches  96 ,  97  are installed on the disc curve walls  94 ,  95 . Consequently, the installed positions of the disc detecting switches  96 ,  97  can also be located at positions opposite to the clip discs  74 . FIGS. 9A and 9B show examples where the disc detecting switches  96 ,  97  are arranged to the positions opposite to the clip discs  74 . 
     Each of the disc detecting switches  96 ,  97  has a contact portion  99  which is pushed by the insertion of the discs  11 ,  12 . With respect to FIGS. 9A and 9B, the contact portion  99  can be moved up and down, and is actuated upward due to a spring (not shown) installed inside each disc detecting switches  96 ,  97 . Therefore, as shown in FIG. 9A, the disc detecting switches  96 ,  97  are assembled such that the contact portion  99  is opposite to the touch portion  88  of the clip disc  74 . 
     Accordingly, as shown in FIG. 9B, as the discs  11 ,  12  are inserted to the carrier unit  70 , the discs  11 ,  12  are clamped between the clip discs  74  and the disc detecting switches  96 ,  97 . Furthermore, the discs  11 ,  12  can be strongly held between the clip discs  74  and the disc detecting switches  96 ,  97  because the tongue pieces  86  are elastic and the contact portion  99  is actuated upwards. As a result, according to the configuration in FIG. 9B, because in addition to the switching function, the disc detecting switches  96 ,  97  can achieve the function equivalent to the second clip disc  74 - 2  installed on the right lower half portion  72 , the part number can be reduced and the carrier unit  70  can become compact and smaller. 
     Turning to FIG. 1 again for further description, the carrier unit  70 , having the structure mentioned above, is movably installed in the holder  40 . The base cover  120  is assembled over the upper portion of the holder  40 . The base cover  120  is formed from a metal plate by press working, comprising a ceiling plate  121 , a right side plate  122  and a left side plate  123 . 
     A first and a second recess  124 ,  125  are formed on the ceiling plate  121 , and particularly a slit  126  is formed on the first recess  124 . In addition, axis holes  127  are respectively formed on the right side plate  122  and the left side plate  123  for axially receiving the rotational axis  57  formed on the holder  40 . The rotational axis  57  and the axis hole  127  at the left side are not shown in FIG.  1 . 
     The base cover  120 , having the structure mentioned above, is fixed on the base  20 , and therefore the position of the base cover  120  is not changed with respect to the base  20 . Additionally, referring to FIGS. 4A and 4B, the holder  40  can be swung between the base  20  and the base cover  120 . 
     Moreover, a front bezel  130  is assembled in front of the disc apparatus  10  (referring to FIG.  2  and FIGS.  4 A and  4 B). An insertion opening  133  is formed on the front bezel  130 , and each of the discs  11 ,  12  and the disc cartridge  13  can be inserted to and removed from the disc apparatus  10  through the insertion opening  133 . 
     Caps  131 ,  132  for opening and closing by an open/close mechanism (not shown) are installed on the insertion opening  133 . The insertion opening is closed by the caps  131 ,  132  when the discs  11 ,  12  and the disc cartridge  13  are not inserted to or removed from the disc apparatus  10 , for preventing dust from entering the disc apparatus  10 . 
     Next, the operations of the recording medium loading apparatus having the structure above is described in detail as follows. As shown in FIG. 22, the 8 cm-disc detecting switch  96  (referring to  8 -SW 96 , hereinafter), the 12 cm-disc detecting switch  97  (referring to  12 -SW 97 , hereinafter), the disc cartridge detecting switch  98  (referring to DC-SW 98 , hereinafter), the clamping motor  68 , the loading motor  100  and the switches SW 1 ˜SW 3  are connected to the control device  150 . Then, the clamping motor  68  and the loading motor  100  are controlled to drive based upon signals from the switches  96 ,  97 ,  98  and the switches SW 1 ˜SW 3 . At this time, the control device  150  performs a control operation shown in FIGS. 23 to  26 . The concrete control operation executed by the control device  150  is described below. 
     As the control process shown in FIG. 23 starts, in step  1  (step is referring to “S” in the drawings), the control device  150  determines whether the 8 cm disc  11  is inserted to the carrier unit  70  based upon the output signal of the switch  8 -SW 96 . Then, the process in FIG. 24 begins if the switch  8 -SW 96  is ON, i.e., the control device  150  determines the 8 cm disc  11  is inserted to the carrier unit  70 . In addition, proceed to step  2  (S 2 ) if the switch  8 -SW 96  is OFF, i.e., the control device  150  determines the 8 cm disc  11  is not inserted to the carrier unit  70 . 
     In step  2  (S 2 ), the control device  150  determines whether the 12 cm disc  12  is inserted to the carrier unit  70  based upon the output signal of the switch  12 -SW 97 . Then, the process in FIG. 25 begins if the switch  12 -SW 97  is ON, i.e., the control device  150  determines the 12 cm disc  12  is inserted to the carrier unit  70 . In addition, proceed to step  3  (S 3 ) if the switch  12 -SW 97  is OFF, i.e., the control device  150  determines the 12 cm disc  12  is not inserted to the carrier unit  70 . 
     In step  3  (S 3 ), the control device  150  determines whether the disc cartridge  13  is inserted to the carrier unit  70  based upon the output signal of the switch DC-SW 98 . Then, the process in FIG. 26 begins if the switch DC-SW 98  is ON, i.e., the control device  150  determines the disc cartridge  13  is inserted to the carrier unit  70 . In addition, return to step  1  (S 1 ) again if the switch DC-SW 98  is OFF, i.e., the control device  150  determines the disc cartridge  13  is not inserted to the carrier unit  70 . 
     FIG. 2 shows a status for a negative decision (“NO” is determined) in any one of the step  1 ˜step  3 . The status indicates discs  11 ,  12  and the disc cartridge  13  is not inserted to the disc apparatus  10 , and more concretely FIG.  2  and FIGS.  21 A˜ 21 F show this status. At this time, the carrier unit  70  moves to the position in the arrow Y 2  direction, referring to the eject position P 1  hereinafter. 
     When the carrier unit  70  is at the eject position P 1 , the switch SW 1  is engaged with the first protrusion  141   a  of the upper cam  141 , the switch SW 2  is engaged with the first protrusion  142   a  of the lower cam  142 , and the switch SW 3  is opposite to the first recess  141   b  of the upper cam  141 . Accordingly, the ON/OFF status for the switches SW 1 ˜SW 3  is [SW 1 , SW 2 , SW 3 ]=[ON, ON, OFF]. 
     Furthermore, in the following description, the ON/OFF status for the switches SW 1 ˜SW 3  is represented by the foregoing shown bracket, in which the left one represents the status of the switch SW 1 , the middle one represents the status of the switch SW 2 , and the right one represents the status of the switch SW 3 . 
     In addition, as described above, when the carrier unit  70  is at the eject position P 1 , the lever body  61  of the disc lever  60  is in contact with a graded cam portion N 1  formed inside the carrier unit  70  as shown in FIG. 11A, which will be described in detail below. Thereby, the disc lever  60  resists the actuating force of the disc lever actuating spring  65 , and then retrocedes to a position without interfering with the movement of the carrier unit  70 . In addition, the cartridge lever  77  is capable of displacing in the arrow Y 1 , Y 2  directions with respect to the carrier unit  70  by means of the axis portion  105  being moved in the cartridge lever guide grooves  103 ,  104 . Furthermore, the cartridge lever  77  is moved by the cartridge lever actuating spring  108  in the arrow Y 2  direction. 
     Accordingly, when the carrier unit  70  is at the eject position P 1 , an engaging jaw  106  formed on the cartridge lever  77  is engaged with a cartridge lever retroceding cam  54  assembled on the right rail  50 . Then, when the carrier unit  70  is moved to the eject position P 1 , the axis portion  105  is restrictively located within the cartridge lever guide grooves  103 ,  104  in the arrow Y 1  direction. 
     A tilted surface is formed on the cartridge retroceding cam  54 , and the engaging jaw  106  of the cartridge lever  77  is engaged with tilted surface. Therefore, as the cartridge lever  77  pushes the tilted surface, the engaging jaw  106  resists the actuating force of the cartridge lever actuating spring and displaces along the tilted surface, thereby the cartridge lever  77  is slightly rotated counterclockwise centered on the axis portion  105 . 
     However, a cover N 2  (a portion of the cover N 2  is shown in FIG. 2) of the disc apparatus  10  is arranged on the outside (in the arrow X 2  direction) of the cartridge lever  77 . Therefore, the rotation toward the counterclockwise direction of cartridge lever  77  is further restricted by means of the outer side surface of the cartridge lever  77  being contact with the cover N 2 . 
     Now, focus on the position of the cartridge lever  77  with respect to the carrier unit  70  when the carrier unit  70  is at the eject position P 1 . As described above, when the carrier unit  70  is at the eject position P 1 , the axis portion  105  is restrictively located within the cartridge lever guide grooves  103 ,  104  in the arrow Y 1  direction because the cartridge lever  77  is in contact with the cartridge lever retroceding cam  54  and the cover N 2 . 
     Therefore, the cartridge lever  77  is also displaced in the arrow Y 1  direction with respect to the carrier unit  70 . As a result, even though the carrier unit  70  is at the eject position P 1 , the cartridge lever  77  doesn&#39;t protrude from the front surface  89  of the carrier unit  70  in the arrow Y 2  direction. 
     For a disc apparatus using a conventional tray, the tray extends forward from the disc apparatus in the ejecting status, increasing the installation space and resulting in tray damage. However, according to the disc apparatus  10  of the invention, even if in the ejecting status, it never protrudes from the front of the disc apparatus  10 . Therefore, when the disc apparatus  10  is installed, the installation space can be saved and occurrence of malfunction can be avoided. 
     On the other hand, the shutter lever  78  is at a position guided in the slit  126  (omitted in FIG. 2) formed on the base cover  120  and rotated clockwise. In the status, the shutter driving pin  113  is located at the engaging position engaged with the shutter  15  formed on the disc cartridge  13 . 
     As shown in FIG. 4A, when the carrier unit  70  is at the eject position P 1 , the holder  40  moves to the moving-up position. When the holder  40  is at the moving-up position, the carrier unit  70  faces to the insertion opening  133  of the front bezel  130 , allowing the insertion of the discs  11 ,  12  and the disc cartridge  13 . 
     First, the transferring operation when the 8 cm disc  11  is inserted to the disc apparatus  10  is described with reference to FIGS.  12 ˜ 14 . In the ejecting status of the disc apparatus  10  shown in FIG. 2, as the 8 cm disc  11  is inserted to the carrier unit  70  through the front bezel  130 , the 8 cm disc  11  is guided to the disc facing surface  93  and moved in the arrow Y 1  direction. Then, the 8 cm disc  11  is in contact with the 8 cm-disc curve wall  94  and held by the 8 cm disc tongue piece  86 - 8  (the clip disc  74 ), referring to FIGS. 7A,  7 B to  9 A,  9 B. In addition, the 8 cm disc detecting switch  96  is operated due to the press of the 8 cm disc  11  by means of the 8 cm disc  11  being in contact with the 8 cm-disc curve wall  94 . Thereby, the control device  150  can detect that the 8 cm disc  11  is held by the carrier unit  70 . Accordingly, a positive determination is made in step  1  (S 1 ), and then the control device  150  begins the control process shown in FIG.  24 . In addition, the carrier unit  70  moves in the arrow Y 1  direction due to the insertion of the 8 cm disc  11 , thereby the switch SW 1  is detached from the first protrusion  141   a  of the upper cam  141 . As a result, the switching status of the switches SW 1 ˜SW 3  becomes [OFF, ON, OFF]. 
     Referring to FIG. 24, the control device  150  begins to apply a voltage to the loading motor  100  in step  10 , thereby the gear  102  is rotated through the gear group  101 . At this time, during which the carrier unit  70  moves from the position shown in FIG. 2 to a predetermined distance in the arrow Y 1  direction, the control device  150  executes a control such that the driving voltage applied to the loading motor  100  is about half to 20% (0.2×E) of the normal driving voltage (E volts), wherein this control status is referred to a loading motor assist status. 
     Concretely, during the time the carrier unit  70  moves from the eject position P 1  shown in FIG. 2 to the position shown in FIG. 12, a voltage of about half to 20% (0.2×E) of the normal driving voltage (E) is applied to the loading motor  100 . In addition, the 8 cm disc loading start position ( 8 L start position for short) is referred to as the position of the carrier unit  70  in FIG. 12, which is further indicated by P 2  in FIG.  12 . 
     As described above, because the driving force generated by the loading motor  100  decreases when the voltage applied to the loading motor  100  decreases, the carrier unit  70  cannot move under such condition. However, an inserting force, which is applied by an operator for inserting the 8 cm disc  11  to the disc apparatus  10 , is applied to the carrier unit  70  when the 8 cm disc  11  is inserted, by which the carrier unit  70  begins to move toward the arrow Y 1  direction. 
     Accordingly, the insertion force of the operator assists the driving force of the loading motor  100  in the operation where the operator inserts the 8 cm disc  11  to the first loading start position P 2 . Therefore, the 8 cm disc  11  can be inserted using the small insertion force applied by the operator, thereby the operation property can be improved when the 8 cm disc  11  is inserted. 
     In addition, the control device  150  constantly monitors whether the switch  8 -SW 96  becomes OFF (step  11 , S 11 ) in the loading motor assist status above. Thereafter, the procedure proceeds to step  12  (S 12 ) when a positive determination (namely, the switch  8 -SW 96  is OFF) in step  11  (S 11 ) is determined, and then the control device  150  drives the carrier unit  70  in a reverse loading direction. Thereby, the carrier unit  70  returns to the eject position P 1  again. 
     For example, the situation that the positive determination is made in step  11  is that the operator immediately notices after a different disc-shaped recording medium is inserted by mistake, and the 8 cm disc inserted by mistake is withdrawn. According to the embodiment of the invention, in the loading motor assist status executed in step  10 , the 8 cm disc  11  can be withdrawn during the transfer because the move of the carrier unit  70  is stopped when the operator releases the insertion force. The operator can exchange the 8 cm disc at the time that the mistaken insertion is noticed without waiting until the 8 cm disc is loaded to the loaded position as in the conventional method, thereby the usability can be improved. In addition, if it determines that the 8 cm disc  11  is withdrawn in step  11 , the carrier unit is automatically returned to the eject position P 1  by the process in step  12 . 
     In addition, the control device  150  constantly monitors whether the switch SW 3  is switched from OFF to ON in step  13  (S 13 ). Referring to FIG. 21B, the position that the switch SW 3  is switched from OFF to ON corresponds to the position that the switch SW 3  is engaged with the second protrusion  141   c  of the upper cam  141 . 
     In the embodiment of the invention, the position that the switch SW 3  is engaged with the second protrusion  141   c  is set to the  8 L start position P 2 , referring to FIG.  21 B. Therefore, the steps  11 ,  13  are repeatedly executed until the positive determination is made in step  13  (S 13 ), or in other words until the carrier unit  70  moves to the  8 L start position P 2 . 
     Referring to FIGS. 11A to  11 C, the operation of the cartridge lever  60  is described during which the carrier unit  70  moves from the eject position P 1  to the  8 L start position P 2 . FIGS. 11A to  11 C show the carrier unit  70  and the disc lever  60  viewed from inside, wherein FIG. 11A shows a status wherein the carrier unit  70  is at the eject position P 1 , FIG. 11B shows a status wherein the carrier unit  70  is between the eject position P 1  and the  8 L start position P 2 , and FIG. 11C shows a status wherein the carrier unit  70  is at the  8 L start position P 2 . 
     The graded cam N 1  formed inside the carrier unit  70  moves in the arrow Y 1  direction due to the fact that the carrier unit  70  moves from the eject position P 1  to the  8 L start position P 2 . Thereby, the disc lever  60  slides in contact with the graded cam N 1  formed inside the carrier unit  70  by the actuating force of the disc lever actuating spring  65 , and then rotated counterclockwise (the arrow C 1  direction in FIG.  12 ). Then, the engaging jaw  63  formed on the disc lever  60  is engaged with the rear portion in the insertion direction of the 8 cm disc  11 , as shown in FIGS. 11C and 12. 
     The disc lever  60  presses the rear portion of the 8 cm disc  11  in the disc insertion direction by the actuating force of the disc lever actuating spring  65  when the lever body  61  is separated from the graded cam N 1 . 
     Accordingly, the front portion in the insertion direction of the 8 cm disc  11  is held by the clip disc  74  and the rear portion in the insertion direction of the 8 cm disc  11  is held by the disc lever  60 . In the embodiment of the invention described above, even if the 8 cm disc  11  is not enfolded in a cartridge, the 8 cm disc  11  can be prevented from detaching from the carrier unit  70  and can be stably transferred because both the front and the rear portions in the insertion direction are held. 
     In addition, the lever body  61  adjusts a rotational operation time by the graded cam N 1  formed inside the carrier unit  70 . The engaging jaw  63  is in contact with the rear portion in the insertion direction of the 8 cm disc  11  after the maximum diameter portion of the 8 cm disc  11  (the maximum distance portion with respect to the arrow X 1 , X 2  directions, i.e., the center position) passes in the arrow Y 1  direction, thereby the disc insertion loading can be reduced. Therefore, the actuating force of the disc lever spring  65  is resisted by the outer circumference of the disc, and it is not necessary to rotate the disc lever  61  in the arrow C 2  direction, to achieve a disc apparatus with small disc insertion loading. 
     Now, assuming that the engaging jaw  63  of the disc lever  60  is engaged with the 8 cm disc  11  before passing the maximum diameter portion of 8 cm disc  11 , i.e., as the carrier unit  70  begins to move, the 8 cm disc  11  is promptly engaged, the disc lever  60  resists the actuating force of the disc lever actuating spring  65  and has to be rotated counterclockwise (the arrow C 2  direction in FIG. 12) with respect to FIG.  11 . Therefore, for the configuration that the engaging jaw  63  is engaged with the 8 cm disc  11  before passing the maximum diameter portion of 8 cm disc  11 , the required disc insertion loading becomes large for the inserting the 8 cm disc  11 . 
     In regard to the problem above, according to the embodiment of the invention, because the engaging jaw  63  is contact with the 8 cm disc  11  due to the cam N 1  immediately after the maximum diameter portion of the 8 cm disc  11  passes in the arrow Y 1  direction and the disc lever  60  is rotated only in the actuating direction of the disc lever actuating spring  65  when the 8 cm disc  11  is inserted, the disc insertion loading can be reduced. 
     On the other hand, the cartridge lever  77  is actuated by the cartridge actuating spring  108  and the axis portion  105  moves in the arrow Y 2  direction within the cartridge lever guide grooves  103 ,  104  due to the fact that the carrier unit  70  moves from the eject position P 1  to the  8 L start position P 2 . Namely, the cartridge lever  77  relatively moves in the arrow Y 2  direction with respect to the carrier unit  70 . 
     However, the engaging jaw  106  of the cartridge lever  77  is maintained in a status contact status with the cartridge lever retroceding cam  54 , and therefore the position of the cartridge lever  77  is not changed with respect to the holder  40 . 
     In addition, the cartridge  77  extends out of the front surface  89  of the carrier unit in the arrow Y 2  direction when the carrier unit  70  moves to the  8 L start position P 2  shown in FIG.  12 . However, the cartridge lever  77  does not protrude out of the disc apparatus  10  because the carrier unit  70  moves within the disc apparatus  10 . 
     On the other hand, when a positive determination is made in step  13  (S 13 ) in FIG. 24, i.e., when it is determined that the carrier unit  70  has moved to the  8 L start position P 2 , the control device  150  applies a normal voltage (E) to the loading motor  100  in step  14  (S 14 ). Therefore, the carrier unit  70  begins to move in the arrow Y 1  direction due to the driving force of the loading motor  100 . When the carrier unit  70  moves to a position where a center hole  11   a  formed on the center of the 8 cm disc  11  is coincident with the turntable  24  as shown in FIG. 13, the control device  150  stops the transfer of the 8 cm disc. Furthermore, in the following description, the position that center hole  11   a  of the 8 cm disc  11  is coincident with the turntable  24  is referred to as the 8 cm disc loading finish position ( 8 L finish position for short), indicated by P 4  in FIG.  13 . Additionally, at this time, the position of the 8 cm disc  11  is referred to as the 8 cm disc loaded position. 
     After the process in step  14  (S 14 ) is executed, the control device  150  constantly monitors whether the switch SW 2  is switched from ON to OFF in step  15  (Sl 5 ). Referring to FIG. 21D, the position that the switch SW 2  is switched from ON to OFF corresponds to the position where the switch SW 2  is detached from the protrusion  142   a  of the lower cam  142  and opposite to the recess  142   b.    
     In the embodiment of the invention, the position that the switch SW 2  is opposite to the recess  142   b  is set to the  8 L finish position P 4  (referring to FIG.  21 D). Therefore, the carrier unit  70  is continuously moved until the positive determination in step  15  (S 15 ) is made, or until the carrier unit  70  is moved to the  8 L finish position P 4 . 
     When the carrier unit  70  is moved from the  8 L start position P 2  to the  8 L finish position P 4 , a status is maintained that the rear portion in the insertion direction of the 8 cm disc  11  is constantly held by the disc lever  60 . Namely, the disc lever  60  is freely rotated centered on the rotational axis  62  and constantly actuated in the counterclockwise direction (the direction indicated by the arrow C 1  in FIG. 12) by the rotational axis  62 . Therefore, the 8 cm disc  11  is transferred in the arrow Y 1  direction and then the disc lever  60  is rotated, thereby the disc lever  60  is constantly maintained to engage with the rear portion in the insertion direction of the 8 cm disc  11 . Therefore, the 8 cm disc  11  is firmly held by the carrier unit  70  and the disc lever  60  and then stably transferred. 
     In addition, because the axis portion  105  is restrictively moved to the position in the arrow Y 2  direction with in the cartridge lever guide grooves  103 ,  104  and further due to the fact that the carrier unit  70  is moved in the arrow Y 1  direction, the cartridge lever  77  is moved in the arrow Y 1  direction together with the carrier unit  70 . 
     At this time, the engaging jaw  106  is detached from the cartridge lever retriceding cam  54 , rotated clockwise by the actuating force of the cartridge lever actuating spring  108  and then moved in the arrow Y 1  direction. Accordingly, the cartridge lever  77  is rotated clockwise centered on the axis portion  105  along the right rail  50  and the side surface of the cartridge lever  77  is detached from the edge  53   a.  The cartridge lever  77  is along the right rail  50 , extending along the arrow Y 1 , Y 2  directions in FIG.  12 . 
     On the other hand, when the positive determination is made in step  15  (S 15 ), i.e., when the 8 cm disc  11  is transferred to the  8 L finish position where the center hole  11   a  is coincident with the turntable  24 , the control device  150  stops the loading motor  100  in step  16  (S 16 ) to stop the move of the carrier unit  70 . Then, proceed to step  17  (S 17 ) for executing the clamp process. 
     Furthermore, before the clamp process, in order to increase the accuracy of the carrier unit stop position, the moving speed of the carrier unit  70  is slowed down and can be moved forward and backward. For example, the loading motor  100  is driven in the reverse direction such that the speed of the carrier unit  70  becomes 1/2 in response to the switch SW 2  switched from ON to OFF in step  15 , and then the loading motor  100  is driven in the positive direction such that the speed of the carrier unit  70  becomes 1/4 in response to the switch SW 2  switched from OFF to ON, and furthermore, the loading motor  100  is stopped in response to the switch SW 2  switched from ON to OFF. By performing such an operation above, the accuracy of the carrier unit stop position can be increased. 
     As for the clamp process in step  17  (S 17 ), when the 8 cm disc  11  is transferred to the  8 L finish position P 4  at which the center hole  11   a  and the turntable  24  is conincident, the clamping motor  68  is driven to make the holder driving slider  30  move in the arrow X 1  direction as shown in FIG.  3 . Thereby, the holder  40  is moved centered on the rotational axis  57  from the moving-up position shown in FIG. 4A to the moving-down position shown in FIG. 4B, and then the 8 cm disc  11  is moved down and held by the turntable  24 . Additionally, as described above, the clamper  58  assembled on the holder  40  is absorbed by the turntable  24  due to the absorption force of the clamp magnet, and therefore the 8 cm disc  11  is clamped between the clamper  58  and the turntable  24 . 
     The 8 cm disc  11  becomes rotatable by the disc motor  25 . However, the 8 cm disc  11  cannot be rotated in the status held by the carrier unit  70  and the disc lever  60 . Therefore, the disc lever  60  is retroceded from the position holding the 8 cm disc  11  in the clamp process. The operation retroceding from the position where the disc lever  60  holds the 8 cm disc  11  is described in detail as follows. As described above, the first and the second disc lever driving cams  28 ,  29  are installed on the base  20  in a standing manner. The first disc lever driving cam  28  is installed to a position corresponding to the position of the disc lever  60  when the carrier unit  70  moves to the  8 L finish position P 4 . 
     The disc lever  60  is rotated centered on the rotational axis  62  when the carrier unit  70  moves in the arrow Y 1  direction and the 8 cm disc  11  is transferred in the same direction. Then, the engaging portion  66  of the disc lever  60  is opposite to the first disc lever driving cam  28  when the 8 cm disc  11  is moved to the  8 L finish position P 4  in FIG.  13  and then the disc lever  60  is rotated to the position as shown in FIG.  13 . 
     Accordingly, due to the fact that the holder  40  is moved from the moving-up position to the moving-down position, the first disc lever driving cam  28  is engaged with the engaging portion  66  of the disc lever  60  and then the disc lever  60  is rotated in the arrow C 2  direction shown in FIG.  14 . As a result, the engaging jaw  63  installed on the disc lever  60  is detached from the 8 cm disc  11 , as shown in FIG.  14 . 
     At this time, as shown in FIG. 4A, the rotation of the disc lever  60  can be smoothly rotated because a tilt surface is formed on the first disc lever driving cam  28 . Additionally, according to the embodiment, in order to cause the disc lever  60  to detach from the 8 cm disc  11 , the move of the holder  40  is used as a driving source to rotate the disc lever  60  without using any additional driving device such as a solenoid etc. Therefore, the disc lever  60  can be exactly detached from the 8 cm disc  11  by a simple structure. 
     However, the 8 cm disc  11  is maintained held by the carrier unit  70  at the time point that the process in step  17  (S 17 ) is finished. Therefore, even if the disc lever  60  is detached from the 8 cm disc  11 , the 8 cm disc still cannot be rotated. 
     As described above, when the carrier unit  70  is transferred to the  8 L finish position P 4 , the 8 cm disc  11  is clamped between the clamper  58  and the turntable  24 . Namely, in such a situation, it is impossible that the 8 cm disc  11  can be moved in the arrow Y 1 , Y 2  directions. 
     The control device  150  executes step  18  in FIG. 24 whether the 8 cm disc  11  is clamped is detected by a detecting switch (not shown), and in which the loading motor  100  is driven to cause the carrier unit  70  to move to the position shown in FIG.  14 . Furthermore, in the following description, the position of the carrier unit  70  shown in FIG. 14 is referred to as the 8 cm disc retrocede position ( 8 L retrocede position for short), indicated by P 5  in the drawing. 
     The control device  150  determines whether the switch SW  3  is switched from ON to OFF in step  19  (S 19 ) in order to cause the carrier unit  70  stop at the  8 L retrocede position P 5 . Referring to FIG. 21, the position that the switch SW 3  is switched from ON to OFF corresponds to the position wherein the switch SW 3  is detached from the second protrusion  141   c  of the upper cam  141  and then is opposite to the second recess  141   d.    
     Referring to FIG. 21E, the position that the switch SW 3  is opposite to the second recess  141   d  is set to the  8 L retrocede position P 5  according to the embodiment of the invention. Then, when the positive determination is made in step  19  (S 19 ), the control device  150  executes the process in step  20  to stop the loading motor  100 , by which the carrier unit  70  is stopped at the  8 L retrocede position P 5 . 
     As described above, at the status wherein the 8 cm disc  11  is clamped, by means of the carrier unit  70  being moved from the  8 L finish position to the  8 L retrocede position, each clip disc  74  is detached from the 8 cm disc  11 . As a result, the 8 cm disc  11  held by the carrier unit  70  is also released, and then the reproducing or recording process can be performed to the 8 cm disc  11 . 
     Moreover, when the 8 cm disc  11  is ejected from the disc apparatus  10 , the operation is reverse to the loading operation described above, which detailed description is omitted. The normal voltage (E) is also applied to the loading motor from the  8 L start position P 2  shown in FIG. 12 to the eject position P 1  shown in FIG. 2 when the 8 cm disc  11  is ejected. Therefore, the operation that the operator takes the 8 cm disc  11  out of the carrier unit  70  is in a status wherein the carrier unit  70  is at the eject position shown in FIG.  2 . The taking-out operation of the 8 cm disc  11  can be easily processed because the 8 cm disc  11  is greatly drawn out of the front bezel  130  in such a status. 
     Next, the control operation executed by the control device  150  when the positive determination is made in the step  2  shown in FIG. 23, and the transferring operation for inserting the 12 cm disc  12  to the disc apparatus  10  is described with reference to FIGS.  15 ˜ 17 . In the eject status shown in FIG. 2 (namely, the carrier unit  70  is at the eject position P 1 ), when the 12 cm disc  12  is inserted to the disc apparatus  10  through the front bezel  130 , the 12 cm disc  12  is guided to the disc facing surface  93  and moved in the arrow Y 1  direction to be in contact with the 12 cm-disc curve wall  95 , and then held by the 12 cm disc tongue piece  86 - 12  (clip disc  74 ). 
     In addition, the 12 cm disc detecting switch  97  is pressed by the 12 cm disc  12  because the 12 cm disc  12  is contact with the 12 cm-disc curve wall  95 . Therefore, as the positive determination is made in step  2 , the control device  150  starts the procedure in FIG.  25 . Namely, the control device  150  can detect that the 12 cm disc  12  is held by the carrier unit  70 . 
     When the procedure in FIG. 25 starts, the control device  150  causes the loading motor  100  to be at the loading motor assist status. When the 12 cm disc  12  is held by the carrier unit  70  is detected, the control device  150  begins to apply voltage to the loading motor  100 . At this time, the control device  150  also applies a voltage about half to 20% (0.2×E) of the normal driving voltage (E) to the loading motor  100  while the carrier unit  70  is moved from the position in FIG. 2 to the position in FIG. 15 when the 12 cm disc  12  is inserted, by which the operational property during disc insertion can be improved. In the following description, the position of the carrier unit  70  shown in FIG. 15 is referred to the 12 cm disc loading start position ( 12 L start position for short), indicating by P 4  in the drawing. Additionally, the  12 L start position P 4  is set to the same position as the  8 L finish position P 4  in FIG. 13 when the 8 cm disc  11  is transferred. 
     The control device  150  monitors the output of the switch  12 -SW 97  in step  31  (S 31 ) when the carrier unit  70  is moved from the eject position P 1  to the  12 L start position P 4 . In the case wherein the switch  12 -SW 97  becomes OFF, the control device  150  determines that the 12 cm disc  12  is taken out by the operator, and then executes a return process such that the carrier unit  70  returns to the eject position P 1 . 
     Therefore, even if the operator notices a wrong insertion when the 12 cm disc  12  is inserted, the 12 cm disc can be immediately changed as soon as the mistaken insertion is noticed, and therefore the usability can be improved. In addition, by the process in step  32 , because the carrier unit  70  is automatically returned to the eject position P 1  as the disc is drawn, a new 8 cm disc  11 , 12 cm disc  12  or disc cartridge  13  can be rapidly changed to insert to the disc apparatus. 
     On the other hand, the graded cam N 1  is moved in the arrow Y 1  direction because the carrier unit  70  is moved from the eject position P 1  to the  12 L start position P 4 . Therefore, the lever body  61  of the disc lever  60  slides in contact with the graded cam N 1  by the actuating force of the disc lever actuating spring  65  and then is rotated counterclockwise (the arrow C 1  direction in FIG.  15 ). Then, the engaging jaw  63  formed on the disc lever  60  is engaged with the rear portion in the insertion direction of the 12 cm disc  12  as shown in FIG.  15 . After the lever body  61  detaches from the graded cam N 1 , the disc lever  60  uses the actuating force of the disc lever actuating spring  65  to press the 12 cm disc  12 . 
     The 12 cm disc  12  is firmly held because the front portion in the insertion direction is held by the clip disc  74  and the rear portion in the insertion direction is held by the disc lever  60 . Because both the front and the rear portions in the insertion direction are held, even if the 12 cm disc  12  is not enfolded by a cartridge, the 12 cm disc  12  can be prevented from detaching from the carrier unit  70  and can be stably transferred. 
     On the other hand, the cartridge lever  77  is actuated by the cartridge lever actuating spring  108  and by means of the carrier unit  70  being moved from the eject position P 1  to the  12 L start position P 4 , and then the axis portion  105  is moved in the arrow Y 2  direction within the cartridge lever guide grooves  103 ,  104 . The cartridge lever  77  is relatively moved in the arrow Y 2  direction with respect to the carrier unit  70 . Additionally, the  12 L start position P 4  when the 12 cm disc  12  is inserted is set to a position separated by a predetermined distance from the  8 L start position P 2  when the 8 cm disc  11  is inserted in previous description. 
     Accompanying the move toward the  12 L start position P 4  of the carrier unit  70 , the engaging jaw  106  of the cartridge lever  77  is detached from the cartridge lever retroceding cam  54  and rotated clockwise by the actuating force of the cartridge lever actuating spring  108  to move in the arrow Y 1  direction. Thereby, the cartridge lever  77  is rotated clockwise centered on the axis portion  105  along the right rail  50 . As shown in FIG. 15, the cartridge lever  77  is arranged along the right rail  50 , extending in the arrow Y 1 , Y 2  directions. 
     Referring to FIG. 25 again for describing the control operation of the control device  150 , the control device  150  constantly monitors whether the switch SW 2  is switched from ON to OFF in step  33  (S 33 ). Referring to FIG. 21D, the position wherein the switch SW 2  is switched from ON to OFF is the position wherein the switch SW 2  is detached from protrusion  142   a  of the lower cam  142  and opposite to the recess  142   b.    
     In the embodiment of the invention, the position wherein the switch SW 2  is opposite to the recess  142   b  is set to the  12 L start position P 4 , as shown in FIG.  21 D. Accordingly, the processes in steps  31 ,  31  are repeatedly executed until the positive determination in step  33  is made, i.e., until the carrier unit  70  is moved to the  12 L start position P 4 . 
     On the other hand, when a positive determination is made in step  33  (S 33 ) in FIG. 25, i.e., when the carrier unit  70  is moved to the  12 L start position P 4  is determined, the control device  150  applies a normal voltage (E) to the loading motor  100  in step  34  (S 34 ). Therefore, the carrier unit  70  begins to move in the arrow Y 1  direction due to the driving force of the loading motor  100 . When the carrier unit  70  moves to a position that a center hole  12   a  formed on the center of the 12 cm disc  12  is coincident with the turntable  24  as shown in FIG. 16, the control device  150  stops the transfer of the 12 cm disc  12 . Furthermore, in the following description, the position that center hole  12   a  of the 12 cm disc  12  is coincident with the turntable  24  is referred to as the 12 cm disc loading finish position ( 12 L finish position for short), indicating by P 5  in FIG.  16 . Additionally, the  12 L finish position P 5  is set to the same position of the  8 L retroceding position P 5  in FIG. 14 when the 8 cm disc  11  is transferred. Furthermore, the position of the 12 cm disc  12  when the carrier unit  70  is at the  12 L finish position P 5  is referred to the 12 cm disc loaded position. 
     After the process in step  34  (S 34 ) is executed, the control device  150  constantly monitors whether the switch SW 3  is switched from ON to OFF in step  35  (S 35 ). Referring to FIG. 21E, the position that the switch SW 3  is switched from ON to OFF corresponds to a position that the switch SW 3  is detached from the second protrusion  141   c  of the upper cam  141  and opposite to the second recess  142   d.    
     In the embodiment of the invention, the position wherein the switch SW 3  is opposite to the second recess  141   d  is set to the  12 L finish position P 5  (referring to FIG.  21 E). Therefore, the carrier unit  70  is continuously moved until the positive determination in step  35  (S 35 ) is made, i.e., until the carrier unit  70  is moved to the  12 L finish position P 5 . 
     When the carrier unit  70  is moved from the  12 L start position P 4  to the  12 L finish position P 5 , which is similar to the 8 cm disc transfer, a status is maintained that the rear portion in the insertion direction of the 8 cm disc  11  is constantly engaged with the disc lever  60 . Therefore, the 12 cm disc  12  is firmly held by the carrier unit  70  and the disc lever  60  and then stably transferred when the disc  12  is transferred between the  12 L start position P 4  and the  12 L finish position P 5 . 
     In addition, according to the embodiment of the invention, because the disc lever  60  is rotatably installed on the holder  40 , the rear portion in the insertion direction of the 8 cm disc  11  and the 12 cm disc  12 , though having different diameters, can be held by one disc lever  60 . Therefore, the part number of the disc apparatus  10  can be reduced and the structure is simplified. 
     On the other hand, when the positive determination is made in step  35  (S 35 ), i.e., when the 12 cm disc  12  is transferred to the  12 L finish position so that the center hole  12   a  is coincident with the turntable  24 , the control device  150  stops the loading motor  100  in step  36  (S 36 ) to stop the move of the carrier unit  70 . Then, proceed to step  37  (S 37 ) for executing the clamp process. The process of the step  37  is the same clamp process of the step  17  in FIG.  24 . 
     As described above, when the 12 cm disc  12  is moved to the  12 L finish position P 5  at which the center hole  12   a  and the turntable  24  are coincident, the clamping motor  68  is driven to make the holder driving slider  30  move in the arrow X 1  direction as shown in FIG.  3 . Thereby, the holder  40  is moved centered on the rotational axis  57  from the moving-up position shown in FIG. 4A to the moving-down position shown in FIG. 4B, and then the 12 cm disc  12  is moved down and held by the turntable  24 , and additionally clamped between the clamper  58  and the turntable  24 . 
     The 12 cm disc  12  becomes rotatable by the disc motor  25 . However, the 12 cm disc  12  cannot be rotated in the status held by the carrier unit  70  and the disc lever  60 . Therefore, the disc lever  60  is retroceded from the position holding the 12 cm disc  12  after the 12 cm disc  12  is clamped. The operation retroceding from the position that the disc lever  60  and the carrier unit  70  hold the 12 cm disc  12  is described in detail as follows. As described above, the first and the second disc lever driving cams  28 ,  29  are installed on the base  20  in a standing manner. The second disc lever driving cam  29  is installed to a position corresponding to the position of the disc lever  60  when the carrier unit  70  moves to the  12 L finish position P 5 . 
     Namely, the disc lever  60  is rotated centered on the rotational axis  62  when the carrier unit  70  moves in the arrow Y 1  direction and the 12 cm disc  12  transferred in the same direction. Then, the engaging portion  66  of the disc lever  60  is opposite to the second disc lever driving cam  29  when the 12 cm disc  12  is moved to the  12 L finish position P 5  in FIG.  16  and then the disc lever  60  is rotated to the position as shown in FIG.  16 . 
     Accordingly, due to the fact that the holder  40  is moved from the moving-up position to the moving-down position, the second disc lever driving cam  29  is engaged with the engaging portion  66  of the disc lever  60  and then the disc lever  60  is rotated in the arrow C 2  direction shown in FIG.  17 . As a result, the engaging jaw  63  installed on the disc lever  60  is detached from the 12 cm disc  12 , as shown in FIG.  17 . 
     At this time, the actuating rotation of the disc lever  60  can smoothly rotate because a tilt surface is formed on the second disc lever driving cam  29 . Additionally, according to the embodiment, in order to cause the disc lever  60  to detach from the 12 cm disc  12 , the move of the holder  40  is used as a driving source to rotate the disc lever  60  without using any additional driving device. Therefore, the structure of the disc apparatus  10  can be simplified. 
     However, the 12 cm disc  12  is maintained held by the carrier unit  70  at the time point that the process in step  37  (S 37 ) is finished. Therefore, even if the disc lever  60  is detached from the 12 cm disc  12 , the 12 cm disc still cannot be rotated. 
     Next, the operation that the carrier unit  70  is retroceded from the position holding the 12 cm disc  12  is described as follows. 
     As described above, when the carrier unit  70  is transferred to the  12 L finish position P 5 , the 12 cm disc  12  is clamped between the clamper  58  and the turntable  24 . In such a situation, it is impossible for the 12 cm disc  12  to be moved in the arrow Y 1 , Y 2  directions. 
     The control device  150  executes the step  38  in FIG. 25, when whether the 12 cm disc  12  is clamped is detected by a detecting switch (not shown), by which the loading motor  100  is driven to cause the carrier unit  70  to move to the position shown in FIG.  17 . Furthermore, in the following description, the position of the carrier unit  70  shown in FIG. 17 is referred to as the 12 cm disc retrocede position ( 12 L retrocede position for short), indicated by P 6  in the drawing. 
     The control device  150  determines whether the switch SW 3  is switched from OFF to ON in step  39  (S 39 ) in order to cause the carrier unit  70  to stop at the  12 L retrocede position P 6 . Referring to FIG. 21F, the position wherein the switch SW 3  is switched from OFF to ON corresponds to the position wherein the switch SW 3  is detached from the second recess  141   d  of the upper cam  141  and then opposite to the third recess  141   e.    
     In the embodiment, the position wherein the switch SW 3  is engaged with the third recess  141   c  is set to the  12 L retrocede position P 6 . Then, when the positive determination is made in step  39  (S 39 ), the control device  150  executes the process in step  40  to stop the loading motor  100 , by which the carrier unit  70  is stopped at the  12 L retrocede position P 6 . 
     As described above, at the status wherein the 12 cm disc  12  is clamped, by means of the carrier unit  70  being moved from the  12 L finish position P 5  to the  12 L retrocede position P 6 , each clip disc  74  is detached from the 12 cm disc  12 . As a result, the 12 cm disc  12  held by the carrier unit  70  is also released, and then the reproducing or recording process can be performed to the 12 cm disc  12 . 
     Moreover, when the 12 cm disc  12  is ejected from the disc apparatus  10 , the operation is reverse to the loading operation described above, which detailed description is omitted. But, the normal voltage (E) is also applied to the loading motor from the  12 L start position P 4  shown in FIG. 12 to the eject position P 1  shown in FIG. 2 when the 12 cm disc  12  is ejected. Therefore, the operation wherein the operator takes the 12 cm disc  12  out of the carrier unit  70  is in a status wherein the carrier unit  70  is at the eject position shown in FIG.  2 . The taking-out operation of the 12 cm disc  12  can be easily processed because the 12 cm disc  12  is greatly drawn out of the front bezel  130  in such a status. 
     Next, the control operation executed by the control device  150  when the positive determination is made in step  3  shown in FIG. 23 will be described in detail below. The transferring operation for inserting the disc cartridge  13  into the disc apparatus  10  is described with reference to FIGS. 18 and 19. 
     In the eject status of the disc apparatus in FIG. 2, the front end of the disc cartridge  13  first contacts with the front surface  89  of the carrier unit  70  when the disc cartridge  13  is inserted through the front bezel  130 . Because the disc cartridge detecting switch  98  is installed on the front surface  89  (referring to FIG.  10 ), the disc cartridge detecting switch  98  is pressed by means of the disc cartridge  13 &#39;s contact with the front surface  89  of the carrier unit  70 . Thereby, if the positive determination is made in step  3 , the control device  150  starts the process shown in FIG.  26 . In addition, in the status wherein the disc cartridge  13  is in contact with the carrier unit  70 , the shutter driving pin  113  installed on the shutter lever  78  is engaged with the end of the shutter  15  installed on the disc cartridge  13 . 
     When the procedure in FIG. 26 starts, the control device  150  causes the loading motor  100  to be at the loading motor assist status in step  50 . When the disc cartridge  13  is inserted to the disc apparatus  10  is detected, the control device  150  begins to apply voltage to the loading motor  100 . Namely, the control device  150  also applies a voltage about half to 20% (0.2×E) of the normal driving voltage (E) to the loading motor  100  during which the carrier unit  70  is moved from the position in FIG. 2 to the position in FIG. 18 when the disc cartridge  13  is inserted, by which the operational property during disc insertion can be improved. The carrier unit  70  is moved in the arrow Y 1  direction due to the assistance of the driving force of the loading motor  100  as well as the insertion operation of the disc cartridge  13 . Therefore, the disc cartridge  13  can be inserted by a smaller force. In the following description, the position of the carrier unit  70  shown in FIG. 18 is referred to as the disc cartridge loading start position (DL start position for short), indicated by P 3  in the drawing. 
     The control device  150  monitors the output of the switch DC-SW 98  in step  51  (S 51 ) when the carrier unit  70  is moved from the eject position P 1  to the DL start position P 3 . In the case that the switch DL-SW 98  becomes OFF in step  51 , the control device  150  determines that the disc cartridge  13  is drawn by the operator, and then executes a return process such that the carrier unit  70  returns to the eject position P 1  in step  52 . 
     Therefore, even if the operator notices a wrong insertion when the disc cartridge  13  is inserted, the disc cartridge can be immediately changed as soon as the mistake insertion is noticed, and therefore the usability can be improved. In addition, by the process in step  52 , because the carrier unit  70  is automatically returned to the eject position P 1  as the disc cartridge is drawn, a new 8 cm disc  11 , 12 cm disc  12  or disc cartridge  13  can be rapidly changed to insert to the disc apparatus  10 . 
     Therefore, the disc lever  60  is retroceded to a position preventing the insertion of the disc cartridge from disturbance when the carrier unit  70  is moved from the eject position P 1  to the DL start position P 3 . Namely, the disc lever  60  is detached from the graded cam N 1  formed inside the carrier unit  70  because the carrier unit  70  is moved from the eject position P 1  to the DL start position P 3 . However, as described above, because the disc cartridge  13  is in contact with the front surface  89  of the carrier unit  70 , the engaging jaw  63  is continuously in contact with the side surface of disc cartridge  13  even if the lever body  61  is detached from the cam N 1 . Therefore, the disc lever  60  is maintained at a position that the carrier unit  70  is at the eject position P 1 , and then the disc lever  60  does not bar the insertion of the disc cartridge  13 . 
     On the other hand, when the carrier unit  70  begins to move in the arrow Y 1  direction from the eject position P 1  to the position indicated by P 2  (the same position of the  8 L start position in FIG. 12) in FIG. 18, the cartridge lever  77  is relatively moved in the arrow Y 2  direction with respect to the carrier unit  70 . Additionally, the axis portion  105  of the cartridge lever  77  is restrictively moved to the Y 2  position within the cartridge lever guide grooves  103 ,  104  at the time point that the carrier unit  70  is moved to the position P 2 . 
     The engaging jaw  106  of the cartridge lever  77  is maintained in contact with cartridge lever retrocede cam  54  during the move of the carrier unit  70  from the eject position P 1  to the position P 2 , thereby the position of the cartridge lever  77  with respect to the holder  40  is not changed. However, as described above, the cartridge lever  77  is extended from the front surface  89  of the carrier unit  70  in the Y 2  direction because the cartridge lever  77  is moved in the arrow Y 2  direction with respect to the carrier unit  70 . 
     When the carrier unit  70  is moved from the position P 2  to the DL start position P 3 , because the axis portion  105  is restricted in the arrow Y 2  direction by the cartridge lever guide grooves  103 ,  104  at the time point that the carrier unit  70  is moved to the position P 3 , the cartridge lever  77  is moved in the arrow Y 1  direction together with the carrier unit  70 . 
     Thereby, the engaging jaw  106  is detached from the cartridge lever retroceding cam  54  and the cartridge lever  77  is rotated clockwise and moved in the arrow Y 1  direction by the cartridge lever actuating spring  108 . Therefore, the cartridge lever  77  is actuated by the cartridge lever actuating spring  108  and then rotated clockwise centered on the axis portion  105 . Additionally, an engaging recess  16  is formed on the side surface of the disc cartridge  13 , located in the moving trajectory of the engaging jaw  106  of the cartridge lever  77 . 
     Accordingly, as shown in FIG. 18, the engaging jaw  106  is engaged with the engaging recess  16  of the disc cartridge  13  by the rotation of the cartridge lever  77 . Then, accompanied with the carrier unit  70  and in the status wherein the side surface of the cartridge lever  77  is detached from the edge  53   a,  the cartridge lever  77  is maintained in a status wherein the engaging jaw  106  is engaged with engaging recess  16 , and is arranged along the right rail  50 , which is extending in the arrow Y 1 , Y 2  directions. 
     Moreover, the shutter lever  78  is rotated due to the move of the carrier unit  70 . The shutter driving pin  113  is guided to move within the shape of the slit  126  due to the insertion of the carrier unit  70  because the shutter driving pin  113  installed on the shutter  78  is engaged with the slit  126 . 
     Thereby, the shutter lever  78  is rotated and then the shutter  15 , engaged with the shutter driving pin  113 , is opened. At the time point that the shutter is fully opened, the shutter driving pin  113  is detached from the slit  126 , and in addition the move of the shutter lever  78  is restricted by means of the engaging hole  111  engaged with the plate spring  79 . 
     Refer to FIG. 26 again to describe the control operation of the control device  150 . The control device  150  constantly monitors whether the switch SW 1  is switched from OFF to ON in step  53  or whether the switch SW 3  is switched from OFF to ON in step  54 . Referring to FIG. 21C, the position that both the switches SW 1  and SW 3  are ON is the position in FIG.  21 C. In the embodiment of the invention, this position is set to the DL start position P 3 . Therefore, the processes of step  51 ˜ 54  are repeatedly executed until the positive determinations in steps  53 ,  54  are made, i.e., until the carrier unit  70  is moved to the DL start position P 3 . 
     In the disc apparatus  10 , the cartridge lever  77  of the carrier unit  70  holds the inserted disc cartridge  13  to move the disc cartridge  13  to the loaded position, or to eject the disc cartridge  13  at the loaded position to the insertion position. The shutter driving pin  113  of the shutter lever  78  swingably installed on the carrier unit  70  is engaged with shutter  15  of the disc cartridge  13  to open or close the shutter  15  in the process engaging with the slit  126  on the base cover  120  from the insertion position to the loaded position. The plate spring  79  causes the protrusion  116  to engage with the engaging hole  111  of the shutter lever  78  that displaces to the position for opening the shutter  15  of the disc cartridge  13 . Therefore, in the disc apparatus  10 , the shutter driving pin  113  fitting to the long hole  112  of the shutter lever  78  reduces the distance for engaging with the slit  126  and further reduces the loading during the transferring process of the disc cartridge  13 . 
     On the other hand, when both positive determinations in steps  53  and  54  are made, i.e., that the carrier unit  70  has moved to the DL start position P 3  is determined, the control device  150  applies the normal voltage (E) to the loading motor  100  in step  55 . The carrier unit  70  can begin to move in the arrow Y 1  direction only by the driving force of the loading motor  100 , even if the operator does not push the disc cartridge  13 . Then, the disc cartridge  13  engaged with the cartridge lever  77  is also automatically moved in the arrow Y 1  direction. As shown in FIG. 19, when the DVD-RAM  14  enfolded in the disc cartridge  13  is transferred to the position at which the center hole  14   a  is coincident with the turntable  24 , the control device  150  stops the rotation of the loading motor  100  to stop the move of the carrier unit  70 . At this time, the protrusion  116  of the plate spring  79  is engaged with the engaging hole  111  of the shutter lever  78  that displaces to the position for opening the shutter  15  of the disc cartridge  13  to thereby fix the shutter lever  78 . Additionally, because the shutter driving pin  113  fitted to the long hole  112  of the shutter lever is detached from the slit  126 , the disc cartridge  13  can be easily transferred even though the slot-in structure is adopted. Therefore, the loading motor  100  for driving the carrier unit  70  can be miniaturized. 
     Moreover, in the following description, the position of the carrier unit  70 , wherein the center hole  14   a  of the DVD-RAM  14  is coincident with the turntable  24 , is the disc cartridge loading finish position (DL finish position for short), indicated by P 6  in FIG.  19 . Additionally, the DL finish position P 6  is set to the same position as the  12 L retrocede position P 6  in FIG. 17 during the transfer of the 12 cm disc  12 . The position wherein the carrier unit  70  is at the DL finish position P 6  is further referred to as the disc cartridge loaded position. 
     When the carrier unit  70  is moved from the DL start position P 3  to the DL finish position P 6 , the disc lever  60  is in contact with the side surface of the disc cartridge  13  and maintained at the retrocede position without impeding the transfer of the disc cartridge  13 . 
     In addition, after the process in step  55  is executed, the control device  150  constantly determines whether the switch SW 3  is switched from OFF to ON after the switch SW 3  is switched from ON to OFF in step  57 . FIG. 21F shows the position that the switch SW 3  is switched from OFF to ON after the switch SW 3  is switched from ON to OFF. 
     In the embodiment of the invention, the position shown in FIG. 21F is set to the DL finish position P 6 . Therefore, the carrier unit  70  is continuously moved until both the positive determinations in steps  56 ,  57  are made, i.e., until the carrier unit  70  is moved to the DL finish position P 6 . 
     On the other hand, when both the positive determinations in steps  56 ,  57  are made, the control device  150  stops the loading motor  100  in step  58 , thereby, the carrier unit  70  is stopped at the DL finish position P 6 . Additionally, in the subsequent step  59 , the control device  150  drives the clamping motor  68  and causes the holder driving slider  30  move in the arrow X 1  direction (referring to FIG.  3 ). Thereby, the holder  40  is rotated centered on the rotational axis  57  from the moving-up position shown in FIG. 4A to the moving-down position shown in FIG.  4 B. As a result, the disc cartridge  13  is also moved downward. 
     Therefore, the DVD-RAM  14  inside the disc cartridge  13  is held by the turntable  24 , and is clamped between the turntable  24  and the clamper  58 . Accordingly, the DVD-RAM  14  becomes rotatable by the disc motor  25 , and then it is possible to perform the reproducing/recording process to the DVD-RAM  14 . 
     Furthermore, when the disc cartridge  13  is ejected from the disc apparatus  10 , the operation is reverse to the loading operation described above, which detail description is omitted. However, in order to improve the operational property for taking out the disc cartridge  13  when the disc cartridge  13  is ejected, the normal voltage (E) is applied to the loading motor  100  during the whole interval from the DL finish position P 6  to the eject position P 1 . 
     According to the embodiment of the invention mentioned above, when the type of the discs  11 ,  12  or the disc cartridge  13  inserted into and held by the carrier unit  70  is determined by the switches SW 1 ˜SW 3 , the control device  150  utilizes the driving control of the loading motor  100  to cause the carrier unit to move to the proper clamp positions P 4 ˜P 6  corresponding to the determined disc  11 ,  12  or the disc cartridge  13 , and thereafter the disc  11 ,  12  or the disc cartridge  13  is clamped by the turntable  24 . Therefore, even if the size and shape of the disc  11 ,  12  or the disc cartridge  13  are different, the disc  11 ,  12  or the disc cartridge  13  can be accurately and firmly clamped by the turntable  24 . 
     Additionally, in the embodiment of the invention, the detecting positions (P 1 , P 2 , P 4 , P 5 ) of the carrier unit  70  set for the 8 cm disc  11 , the detecting positions (P 1 , P 4 , P 5 , P 6 ) of the carrier unit  70  set for the 12 cm disc  12 , and the detecting positions (P 1 , P 3 , P 6 ) of the carrier unit  70  set for the disc cartridge  11  have positions set to the same in a plurality of positions. 
     More particularly, the eject position P 1  is common for the discs  11 ,  12  and the disc cartridge  13 . In addition, the  8 L finish position P 4  and the  12 L start position P 4 , the  8 L retrocede position P 5  and the  12 L finish position P 5 , the  12 L retrocede position P 6  and the DL finish position P 6  are respectively set to the common position. 
     In the conventional loading apparatus, it requires eleven different detecting positions for all cases where different detecting positions are set for each disc  11 ,  12  and the disc cartridge  13 . However, according to the embodiment of the invention, the detecting positions can be reduced to six positions (P 1 ˜P 6 ) because some of the detecting positions are common. Accordingly, the control process executed by the control device  150  can be simplified, and additionally, the number of the switches (SW 1 ˜SW 3 ) for detecting that the carrier unit  70  is moved to the detecting positions can be reduced. 
     Furthermore, in the embodiment of the invention mentioned above, the switches SW 1 ˜SW 3  and the carrier position detecting cam  140  are used for performing the position detection of the carrier unit  70 . The carrier position detecting cam  140  comprises the upper cam  141  engaged with the switches SW 1 , SW 3  and the lower cam  142  engaged with the switches SW 2 . Then, the position detection of the carrier unit  70  is performed according to the combination of the output signals of the switches SW 1 ˜SW 3 . 
     Therefore, the position detection for the carrier unit  70  having six detecting positions (P 1 ˜P 6 ) can be detected by three switches SW 1 ˜SW 3 , which can reduce the switch number. As a result, the structure of the recording medium loading apparatus and the disc apparatus  10  can be simplified and the part number can be also reduced. 
     Moreover, according to the invention, the switches SW 1 ˜SW 3  are ON/OF by press operation, which is operated by the carrier position detecting cam  140 . Therefore, the position detection becomes possible because the cam shapes formed on the carrier position detecting cam  140  are different for each detecting position of the carrier unit  70 , thereby the position detection of the carrier unit  70  can be accurately performed by the simple structure. 
     Furthermore, in the embodiment mentioned above, the recording medium loading apparatus having a compatible disc apparatus for loading any one of the 8 cm disc  11 , 12 cm disc  12  and the disc cartridge  13  is used as an example for description. However, the invention is not restricted to the compatible disc apparatus, the invention is also suitable for a disc apparatus for only loading the disc cartridge. 
     According to the embodiment above, even if the carrier body is set at the eject position, the holding device does not protrude from the main body of the disc apparatus so that the installation space of the disc apparatus can be saved. In addition, in the process that the carrier body is moved from the eject position to the loaded position, because the recording medium is held by the holding device, the recording medium can be firmly held and transferred even though the installation space of the disc apparatus is saved. 
     In addition, the carrier swingably holds a shutter opening/closing member for opening and closing a shutter installed on the cartridge accompanying with an insertion of the cartridge enfolding the recording medium, and the carrier further comprises: a cam portion for engaging with the shutter opening/closing member to open/close the shutter of the cartridge in a process that the carrier is moved from the eject position to the loaded position; and a holding member for holding the shutter opening/closing member to displace to a position to open the shutter of the cartridge by engaging with the cam portion. 
     The distance that the shutter opening/closing member is engaged with the cam portion is shortened, and therefore the loading in the process of transferring the cartridge can be reduced. Accordingly, the slot-in structure can easily perform the transfer of the cartridge and the motor for driving the transfer member can be miniaturized. 
     The holding member is installed on the carrier for latching the shutter opening/closing member at a time point that the shutter opening/closing member passes the cam portion in a loading process of the cartridge, and for releasing the latch of the shutter opening/closing member at a time point that the shutter opening/closing member is engaged with the cam portion in an eject process of the cartridge. Therefore, even if there is no engagement with the cam portion, the shutter opening/closing member passing the cam portion can be held at the shutter-opened position. The distance that the shutter opening/closing member is engaged with the cam portion is shortened, and therefore the loading process of transferring the cartridge can be reduced. Accordingly, even the slot-in structure can also easily perform the transfer of the cartridge and the motor for driving the transfer member can be miniaturized. 
     While the present invention has been described with a preferred embodiment, this description is not intended to limit our invention. Various modifications of the embodiment will be apparent to those skilled in the art. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.