Patent Publication Number: US-2023162760-A1

Title: Optical disc drive and electronic equipment

Description:
TECHNICAL FIELD 
     The present invention relates to an optical disc drive and electronic equipment. 
     BACKGROUND ART 
     PTL 1 and PTL 2 listed below each disclose an optical disc drive that can be mounted in electronic equipment such as a game machine, a personal computer, or audio-visual (AV) equipment. The optical disc drive includes a conveying roller that contacts an optical disc inserted through an insertion port formed in a front surface of the optical disc drive and that conveys the optical disc to the position of a spindle motor and a chucking pulley that magnetically fixes, to the spindle motor, the optical disc having reached the position of the spindle motor. 
     CITATION LIST 
     Patent Literature 
     
         
         [PTL 1] 
         JP 2015-022780A 
         [PTL 2] 
         JP 2015-022779A 
       
    
     SUMMARY 
     Technical Problem 
     The optical disc drives disclosed in PTL 1 and PTL 2 each further include a mechanism that guides the center of an optical disc to the position of the spindle motor. However, the mechanism is implemented using a plurality of arms, and thus there is a problem that the optical disc drives each have a large number of components. 
     An object of the present invention is to provide an optical disc drive that can guide the center of the optical disc to the position of the spindle motor, while allowing the number of components to be reduced. 
     Solution to Problem 
     An optical disc drive according to the present invention includes an insertion port configured to receive an optical disc, a spindle motor located behind and away from the insertion port, a mechanism configured to convey, to a position of the spindle motor, the optical disc inserted through the insertion port, a frame including a stopper portion configured to come into contact with an outer edge of the optical disc having reached the position of the spindle motor, to restrict backward movement of the optical disc, and a bias member including a contact portion located on a side opposite to the stopper portion across the optical disc having reached the position of the spindle motor, the bias member being configured to use the contact portion to push the optical disc toward the stopper portion. According to the present invention, the center of the optical disc can be guided to the position of the spindle motor, while the number of components can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is an exploded perspective view of an optical disc drive  1  according to an embodiment of the present invention. 
         FIG.  2 A  is a top view of a bottom frame. 
         FIG.  2 B  is a perspective view of the bottom frame. 
         FIG.  2 C  is a cross-sectional view taken along a line c-c depicted in  FIG.  2 A . 
         FIG.  3    is an exploded perspective view depicting a top frame and members disposed in the top frame. 
         FIG.  4    is a perspective view depicting constituent components of a conveying mechanism. 
         FIG.  5    is a rear view of a conveying roller and a roller bracket. 
         FIG.  6    is a partially enlarged view of a right side surface of the bottom frame. 
         FIG.  7    is an exploded perspective view depicting a loading motor and gears. 
         FIG.  8    is a left side view of the gears and the roller bracket. 
         FIG.  9 A  is a left side view of a slider, the gears, and the roller bracket, depicting a case where the slider is placed in a first slide position. 
         FIG.  9 B  is a left side view of the slider, the gears, and the roller bracket, depicting a case where the slider is placed in a second slide position. 
         FIG.  10 A  is a top view of the top frame, depicting a case where no disc is present in the optical disc drive. 
         FIG.  10 B  is a cross-sectional view taken along a line b-b depicted in  FIG.  10 A . 
         FIG.  11    is a top view of the top frame, depicting a case where a disc is placed in an insertion port of the optical disc drive. 
         FIG.  12 A  is a top view of the top frame, depicting a case where the disc is placed in a drive position in the optical disc drive. 
         FIG.  12 B  is a cross-sectional view taken along a line b-b depicted in  FIG.  12 A . 
         FIG.  13    is a perspective view depicting a back side of a switch arm and a rotary arm. 
         FIG.  14    is a perspective view of the base frame and the top frame. 
         FIG.  15    is an exploded perspective view of the base frame. 
         FIG.  16 A  is a bottom view of a bottom case. 
         FIG.  16 B  is a cross-sectional view taken along a line b-b depicted in  FIG.  16 A . 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     An embodiment of the present invention will be described below with reference to the drawings.  FIG.  1    is an exploded perspective view of an optical disc drive  1  according to the embodiment of the present invention. In the description below, X 1  and X 2  depicted in  FIG.  1    denote a left direction and a right direction, Y 1  and Y 2  denote a forward direction and a backward direction, and Z 1  and Z 2  denote an upward direction and a downward direction. In the present embodiment, on an axis CB (see  FIGS.  10 B and  12 B ) of a spindle motor  11  described below, with an optical disc placed on the spindle motor  11 , a direction from the spindle motor  11  toward the optical disc is assumed to be “upward,” and the opposite direction is assumed to be “downward.” Further, among the directions perpendicular to the axis CB of the spindle motor  11 , the direction in which an insertion port is disposed with respect to the position where the spindle motor  11  is disposed is assumed to be “forward,” and the opposite direction is assumed to be “backward.” In addition, a plane perpendicular to the axis CB of the spindle motor  11  is assumed to be a horizontal plane. Further, in members (components), the uppermost position, the lowermost position, the leftmost position, the rightmost position, the foremost position, and the backmost position are respectively assumed to be an upper end, a lower end, a left end, a right end, a front end, and a back end. In addition, a portion of a member including at least the upper end, the lower end, the left end, the right end, the front end, or the back end of the member is respectively assumed to be an upper end portion, a lower end portion, a left end portion, a right end portion, a front end portion, or a back end portion. 
     1. Configuration of Optical Disc Drive 
     The optical disc drive  1  is housed in a cabinet included in electronic equipment such as a game machine, a personal computer, or AV equipment. As depicted in  FIG.  1   , the optical disc drive  1  includes a base frame  2  (base unit). The base frame  2  is generally shaped like a plate, and an optical disc is placed on the base frame  2 . The base frame  2  includes the spindle motor  11  used as a turntable that rotates the optical disc. The spindle motor  11  rotates around an axis CB (see  FIGS.  10 B and  12 B ) perpendicular to an upper surface of the base frame  2 . Further, the base frame  2  includes a circuit board on which the spindle motor  11  is mounted, an optical pickup (optical element), a motor that moves the optical pickup in a front-back direction, and the like. 
     Note that the optical disc is, for example, a compact disc (CD), a digital versatile disc (DVD), a Blu-Ray Disc (registered trademark), or the like. The optical disc drive  1  described in the present embodiment corresponds to an optical disc with a diameter of 12 cm. 
     Further, the optical disc drive  1  includes a bottom frame  3 . As depicted in  FIG.  1   , the bottom frame  3  is shaped like a box, and various members such as the base frame  2  are disposed in the bottom frame  3 . In addition, the optical disc drive  1  includes a top frame  4  attached to an upper side of the bottom frame  3 . The top frame  4  is generally shaped like a plate and attached to the bottom frame  3  to constitute, together with the bottom frame  3 , an inner case that houses the base frame  2 , a conveying roller  20 , a roller bracket  50 , and a loading motor  60  and gears  61   a  to  61   g  described below (see  FIG.  7   ). The bottom frame  3  and the top frame  4  may include resin. 
       FIG.  2 A  is a top view of the bottom frame  3 , and  FIG.  2 B  is a perspective view of the bottom frame  3 .  FIGS.  2 A and  2 B  depict the bottom frame  3  in which various members are disposed. As depicted in  FIGS.  2 A and  2 B , the base frame  2  and the roller bracket  50  to which the conveying roller  20  is attached are disposed inside the bottom frame  3 . Further, a slider  70  is disposed outside the bottom frame  3 . 
     The bottom frame  3 , shaped like a box, includes a rectangular cutout portion  31  at a front upper edge of the bottom frame  3 . The cutout portion  31  and a lower edge of a front end portion of the top frame  4  which is generally shaped like a plate constitute an insertion port into which an optical disc is inserted. The optical disc inserted into the insertion port is placed between the bottom frame  3  and the top frame  4 . More specifically, the optical disc is placed between the conveying roller  20  disposed inside the bottom frame  3  and the top frame  4 , is conveyed by a conveying mechanism A (such as the conveying roller  20 ), and thus placed between the base frame  2  disposed inside the bottom frame  3  and the top frame  4 . 
       FIG.  3    is an exploded perspective view depicting the top frame  4  and members disposed in the top frame  4 . As depicted in  FIG.  3   , a chucking pulley  12 , a switch board  15 , a switch arm  80 , a rotary arm  90 , a first check arm  110 , a second check arm  120 , and a plurality of springs  85 ,  96 , and  116  are disposed in the top frame  4 . Each of the members will be described below in detail. 
     Further, as depicted in  FIG.  1   , the optical disc drive  1  includes a bottom case  5  and a cover  6  as constituent components of an outer case corresponding to an outermost shell of the optical disc drive  1 . The bottom case  5  is shaped like a box, and an inner case including the bottom frame  3  and the top frame  4  is housed inside the bottom case  5 . In this manner, the outer case (the bottom case  5  and the cover  6 ) covers the entire inner case (the bottom frame  3  and the top frame  4 ), allowing dust to be restrained from entering the inside of the optical disc drive  1  or the inside of the bottom frame  3 . Further, the bottom case  5  and the cover  6  may be formed from metal. This allows electromagnetic waves to be restrained from entering the inside of the optical disc drive  1  and from leaking out from the optical disc drive  1 . 
     A rectangular hole portion H is formed in a front surface of the bottom case  5 . When the optical disc drive  1  is seen in front view, the hole portion H is overlaid on a cutout portion  31  formed in the bottom frame  3  and constitutes an insertion port for an optical disc together with the cutout portion  31 . In other words, the optical disc drive  1  includes the bottom case  5  and the bottom frame  3  corresponding to a member provided with the insertion port. 
     Further, the optical disc drive  1  includes a conveying mechanism A that conveys the optical disc, a centering mechanism B that aligns the optical disc, a chucking mechanism C that fixes the optical disc, and a vibration suppression mechanism D that suppresses vibration of the optical disc drive  1 . The conveying mechanism A is configured to convey, to the position of the spindle motor  11 , the optical disc inserted into the insertion port from the outside of the optical disc drive  1  and to convey, to the outside of the insertion port, the optical disc placed on the spindle motor  11 . The centering mechanism B is a mechanism for positioning the optical disc such that the central position of the optical disc aligns with the position of the axis CB corresponding to the rotation center of the spindle motor  11  (hereinafter also referred to as a drive position). The chucking mechanism C is a mechanism for fixing the optical disc in the drive position. The vibration suppression mechanism D is a mechanism for restraining vibration that occurs in the base frame  2  while the optical disc is rotating in the drive position from being transmitted to the inner case (the bottom frame  3  and the top frame  4 ) and the outer case (the bottom case  5  and the cover  6 ). In the present embodiment, the conveying mechanism A is provided in the bottom frame  3 , the centering mechanism B is provided in the base frame  2  and the top frame  4 , C is provided in the top frame  4 , and the vibration suppression mechanism D is provided in the base frame  2 , the bottom frame  3 , and the bottom case  5 . The conveying mechanism A, the centering mechanism B, the chucking mechanism C, and the vibration suppression mechanism D will be described below. 
     2. Conveying Mechanism 
     The conveying mechanism A will be described. The conveying mechanism A includes the conveying roller  20  that conveys, toward the position of the spindle motor  11 , the optical disc inserted through the insertion port of the optical disc drive  1 . The conveying roller  20  is disposed in contact with the optical disc inserted into the insertion port (space between the cutout portion  31  of the bottom frame  3  and the top frame  4 ) of the optical disc drive  1 . In the present embodiment, the conveying roller  20  is located below a conveying path along which the optical disc passes. Thus, the conveying roller  20  contacts a lower surface of the optical disc and conveys the optical disc in the front-back direction. 
     The base frame  2  is disposed inside the bottom frame  3 , and the spindle motor  11  mounted in the base frame  2  is disposed behind and away from the cutout  31  of the bottom frame  3  constituting the insertion port. Further, inside the bottom frame  3 , the conveying roller  20  attached to the roller bracket  50  is disposed in front of the base frame  2 . 
     As depicted in  FIG.  2 B , the optical disc drive  1  includes a spring  25  configured to bias the conveying roller  20  in a direction (upward in this case) toward the conveying path along which the optical disc passes. The spring  25  is attached to a hole portion  53  formed on a left side of the roller bracket  50  with respect to the center of the roller bracket  50 . The spring  25  biases the roller bracket  50  and the conveying roller  20  to place the conveying roller  20  in a conveying position. This brings the conveying roller  20  (a left roller  21 L and a right roller  21 R described below) into contact with the lower surface of the optical disc. 
     The conveying mechanism A is actuated by power received from the loading motor  60 . While placed in the conveying position in contact with the lower surface of the optical disc, the conveying roller  20  is rotated by power from the loading motor  60  to convey, toward the position of the spindle motor  11 , the optical disc inserted through the insertion port (the cutout  31  of the bottom frame  3 ). The conveying roller  20  can be moved by a conveying roller position manipulation mechanism described below between a conveying position (first roller position) where the conveying roller  20  contacts and conveys the optical disc and a retract position (second roller position) located away from the conveying position. The retract position is a position where the conveying roller  20  is located below and away from the conveying path for the optical disc and does not contact the optical disc. 
       FIG.  4    is a perspective view depicting constituent components of the conveying mechanism A. As depicted in  FIG.  4   , the conveying roller  20  includes the left roller  21 L (left roller portion) that is rotatable around an axis CL (first axis) and the right roller  21 R (right roller portion) that is rotatable around an axis CR (second axis), the left roller  21 L and the right roller  21 R being arranged in a lateral direction. The left roller  21 L and the right roller  21 R are cylindrical members separately formed. Thus, the left roller  21 L and the right roller  21 R, which are separate members as described above, can easily be formed. 
     The conveying roller  20  is disposed below the top frame  4 . As depicted in  FIG.  3   , the top frame  4  includes openings  41 L and  41 R at positions respectively corresponding to the left roller  21 L and the right roller  21 R constituting the conveying roller  20 . In a case where the conveying roller  20  is in the conveying position, outer side portions of the left and right rollers  21 L and  21 R are respectively placed inside the openings  41 L and  41 R. 
     As depicted in  FIG.  4   , the left roller  21 L includes a shaft portion  22 L at a left end portion and a coupling portion  23 L at a right end portion. Similarly, the right roller  21 R includes a shaft portion  22 R at a right end portion and a coupling portion  23 R at a left end portion. The left roller  21 L and the right roller  21 R are coupled to each other by the coupling portions  23 L and  23 R. The coupling portion  23 L is fixed to the left roller  21 L, and a tip of the coupling portion  23 L is formed like a frame. Similarly, the coupling portion  23 R is fixed to the right roller  21 R, and a tip of the coupling portion  23 R is formed like a frame. At the central position of the conveying roller  20 , the coupling portions  23 L and  23 R are coupled to each other by the tip of one of the coupling portions  23 L and  23 R being fitted into the frame of the other. The left and right rollers  21 L and  21 R may have the same frame shape. 
     With the coupling portions  23 L and  23 R connected to each other, a first end portion corresponding to one of the left end portion of the left roller  21 L and the right end portion of the right roller  21 R can be moved in an up-down direction with respect to a second end portion corresponding to the other end portion, with the relative positions of the axes CL and CR unchanged. In this case, the first end portion can be moved in the up-down direction with respect to the second end portion with the coupling portions  23 L and  23 R respectively fixed to support portions  51 Lb and  51 Rb and with the angle between the axes CL and CR unchanged. Thus, when a user inserts an optical disc, even in a case where the optical disc is misaligned in the lateral direction, the left end portion of the left roller  21 L or the right end portion of the right roller  21 R is moved in the up-down direction with the angle between the rollers maintained. Thus, the left roller  21 L and the right roller  21 R come into contact with the optical disc at predetermined areas of the optical disc, allowing maintenance of a state in which the optical disc is gripped. Further, for example, compared to a structure in which the left roller  21 L and the right roller  21 R move independently to change the relative positions of the axes CL and CR, the present embodiment with the relative positions of the axes CL and CR unchanged has a simple structure, enabling the number of components of the optical disc drive  1  to be reduced. 
     The left roller  21 L and the right roller  21 R constituting the conveying roller  20  are attached to the single roller bracket  50  and rotatably supported by the roller bracket  50 . As described above, the one roller bracket  50  supports the left roller  21 L and the right roller  21 R, and this configuration enables the number of components of the optical disc drive  1  to be reduced compared to, for example, a configuration in which two brackets respectively support the left roller  21 L and the right roller  21 R. 
       FIG.  5    is a rear view of the conveying roller  20  and the roller bracket  50 . As depicted in  FIGS.  4  and  5   , the roller bracket  50  includes a support portion  51 La that supports the shaft portion  22 L of the left roller  21 L, the support portion  51 Lb that supports the coupling portion  23 L of the left roller  21 L, a support portion  51 Ra that supports the shaft portion  22 R of the right roller  21 R, and the support portion  51 Rb that supports the coupling portion  23 R of the right roller  21 R. As depicted in  FIG.  4    and  FIG.  8    described below, the support portion  51 La has an annular shape. Further, the support portions  51 Lb and  51 Rb are shaped like circular arcs that are open upward. The shaft portion  22 L and the coupling portions  23 L and  23 R are fitted inside the support portions  51 Lb and  51 Rb. Further, the support portion  51 Ra is a protrusion fitted into a hole formed at a right end of the shaft portion  22 R of the right roller  21 R. 
     The support portions  51 Lb and  51 Rb that support the coupling portion  23 L of the left roller  21 L and the coupling portion  23 R of the right roller  21 R are located below the support portions  51 La and  51 Ra that support the shaft portion  22 L of the left roller  21 L and the shaft portion  22 R of the right roller  21 R. Thus, the axis CL of the left roller  21 L and the axis CR of the right roller  21 R are inclined with respect to a horizontal plane (a plane perpendicular to the axis CB of the spindle motor  11 ). As depicted in  FIG.  5   , an optical disc O shaped like a disc is inserted into the insertion port of the optical disc drive  1  along the horizontal plane and is conveyed to the position of the spindle motor  11 . Thus, the axis CL of the left roller  21 L and the axis CR of the right roller  21 R are inclined with respect to the optical disc O placed on the conveying roller  20 . 
     The axis CL of the left roller  21 L is inclined such that the distance between the axis CL and the optical disc O gradually increases from a left end portion of the conveying roller  20  toward a central portion of the conveying roller  20 . Similarly, the axis CR of the right roller  21 R is inclined such that the distance between the axis CR and the optical disc O gradually increases from a right end portion of the conveying roller  20  toward a central portion of the conveying roller  20 . Since the axes CL and CR of the left and right rollers  21 L and  21 R are inclined as described above, the left and right rollers  21 L and  21 R can be brought into contact with the optical disc O except for an area of optical disc O in which data is recorded (a circular area with a radius corresponding to a predetermined distance from the center of the optical disc O). 
     One of a left end portion and a right end portion of the roller bracket  50  can be moved in the up-down direction relative to the other. Thus, one (first end portion) of the left end portion of the left roller  21 L and the right end portion of the right roller  21 R can be moved in the up-down direction relative to the other end portion (second end portion). In the present embodiment, the shaft portion  22 R corresponding to the right end portion of the right roller  21 R can be moved in the up-down direction relative to the shaft portion  22 L corresponding to the left end portion of the left roller  21 L. 
     The left end portion and the right end portion of the roller bracket  50  are supported by the bottom frame  3 . As depicted in  FIG.  4   , the roller bracket  50  includes a shaft portion  52 L at the left end portion and a shaft portion  52 R at the right end portion. The roller bracket  50  includes an axis CA along the lateral direction and is rotatable along the axis CA. The shaft portions  52 L and  52 R are cylindrical protrusions respectively protruding leftward and rightward from the roller bracket  50  and are located on the axis CA of the roller bracket  50  away from each other in the lateral direction. As depicted in  FIG.  2 B , the shaft portion  52 L formed at the left end portion of the roller bracket  50  is fitted into a bearing portion  33 L formed in the bottom frame  3 . Further, the shaft portion  52 R formed at the right end portion of the roller bracket  50  is fitted into a bearing portion  33 R formed in the bottom frame  3 . As depicted in  FIG.  4   , the axis CA of the roller bracket  50  is located in front of and away from the conveying roller  20 . Thus, when the roller bracket  50  rotates around the axis CA, the conveying roller  20  attached to the roller bracket  50  rotationally moves around the axis CA. This movement allows the conveying roller  20  to move between the conveying position where the conveying roller  20  (the left roller  21 L and the right roller  21 R) contacts the optical disc and the retract position located below and away from the conveying position. 
     A supported portion (the shaft portion  52 L or the shaft portion  52 R) is formed at one of the right end portion and the left end portion of the roller bracket  50 , and a support portion (the bearing portion  33 L or the bearing portion  33 R) supports the supported portion and is formed by the bottom frame  3 . The supported portion and the support portion may be formed to permit movement of the supported portion in the up-down direction. Thus, one of the left end portion and the right end portion of the roller bracket  50  can move in the up-down direction with respect to the other, and one (first end portion) of the left end portion of the left roller  21 L and the right end portion of the right roller  21 R can move in the up-down direction relative to the other end portion (second end portion). In other words, depending on the state of the optical disc inserted, one of the left end portion and the right end portion of the roller bracket  50  is displaced in the up-down direction with respect to the other, thus displacing one (first end portion) of the left end portion of the left roller  21 L and the right end portion of the right roller  21 R in the up-down direction relative to the other end portion (second end portion). This makes it possible to maintain an appropriate state of connection between the optical disc and the rollers depending on the state of the optical disc. 
       FIG.  6    is a partially enlarged view of a right side surface of the bottom frame  3 . As depicted in  FIGS.  2 A,  2 B, and  6   , in the present embodiment, the bottom frame  3  includes a right side wall portion  32 R constituting a right end portion (a right frame portion of the box) of the bottom frame  3 . In the right side wall portion  32 R, the bearing portion  33 R is formed. With the roller bracket  50  biased upward by the spring  25 , a gap d extending in the up-down direction is formed between the shaft portion  52 R of the roller bracket  50  and the bearing portion  33 R of the bottom frame  3 . The gap d permits, inside the bearing portion  33 R, movement of the right end portion (shaft portion  52 R) of the roller bracket  50  in the up-down direction. Note that, in  FIG.  6   , the bearing portion  33 R is formed as a cutout but the bearing portion  33 R may be a slot that is elongate in the up-down direction. 
     Further, as depicted in  FIG.  2 B , the bottom frame  3  includes a left side wall portion  32 L constituting a left end portion (a left frame portion of the box) of the bottom frame  3 . Further, inside the bottom frame  3 , a left inner wall portion  34  shaped like a flat plate is formed in parallel with the left side wall portion  32 L. A left bearing portion  33 L is formed in the left inner wall portion  34  such that the shaft portion  52 L of the roller bracket  50  is fitted in the bearing portion  33 L. Inside the bearing portion  33 L, movement of the left end portion (shaft portion  52 L) of the roller bracket  50  in the up-down direction is restricted. 
     The conveying mechanism A includes a conveying roller driving mechanism that rotates the conveying roller  20 . The roller driving mechanism may be coupled to one (second end portion) of the left end portion of the left roller  21 L or the right end portion of the right roller  21 R of which movement in the up-down direction is restricted. When the roller driving mechanism is disposed at the second end portion of which movement in the up-down direction is restricted as described above, the roller driving mechanism and the conveying roller can easily be coupled. In the present embodiment, the bearing portion  33 L of the bottom frame  3  restricts the movement of the left end portion (shaft portion  52 L) of the roller bracket  50  in the up-down direction, thus restricting the movement, in the up-down direction, of the shaft portion  22 L corresponding to the left end portion of the left roller  21 L. Further, as depicted in  FIG.  4   , a gear  24  is attached to the shaft portion  22 L corresponding to the left end portion of the left roller  21 L, and the conveying roller driving mechanism (gear  61   e  described below) is coupled to the gear  24 . A rotational center axis of the gear  24  is located on the axis CL of the left roller  21 L. Note that no gear that is coupled to the conveying roller driving mechanism is attached to the shaft portion  22 R corresponding to the right end portion (first end portion) of the right roller  21 R of which movement in the up-down direction is permitted. 
       FIG.  7    is an exploded perspective view depicting the loading motor  60  and gears  61   a  to  61   g .  FIG.  8    is a left side view of the gears  61   b  to  61   g  and the roller bracket  50 . The gear  61   a  is a worm gear and is fitted around a rotating shaft of the loading motor  60  and meshed with the gear  61   b . The gear  61  configured as a worm gear allows a certain reduction ratio to be achieved with respect to the rotation speed of shaft of the loading motor  60 . Further, as depicted in  FIG.  8   , the gear  61   b  is meshed with the gears  61   a  and  61   c . The gear  61   c  is meshed with the gears  61   b ,  61   d , and  61   f . The gear  61   d  is meshed with the gears  61   c  and  61   e . The gear  61   e  is meshed with the gear  61   c  and with the gear  24  coupled to the left roller  21 L. The gear  61   f  is meshed with the gears  61   c  and  61   g.    
     The conveying mechanism A includes a first transmission mechanism that transmits rotation of the loading motor  60  to the conveying roller  20 , as a part of the conveying roller driving mechanism that rotates the conveying roller  20 . In the present embodiment, the gears  61   a  to  61   e  correspond to the first transmission mechanism. In other words, rotation of the loading motor  60  is transmitted to the gear  24  via the first transmission mechanism corresponding to the gears  61   a  to  61   e . The gear  24  then rotates clockwise or counterclockwise to rotate the left roller  21 L to which the gear  24  is attached and the right roller  21 R coupled to the coupling portion  23 L of the left roller  21 L via the coupling portion  23 R, in the same direction as that in which the gear  24  rotates (clockwise or counterclockwise) at the same speed as that of rotation of the gear  24 . As depicted in  FIG.  8   , at least a part of the loading motor  60  is located behind the gear  61   e  constituting a front end of the first transmission mechanism. Note that the first transmission mechanism is not limited to the gears and may include belts or the like. 
     Further, the conveying mechanism A includes the roller bracket  50  and the slider  70  as the conveying roller position manipulation mechanism that moves the position of the conveying roller  20 . As depicted in  FIG.  2 B , the slider  70  is attached to the left end portion (left side wall portion  32 L) of the bottom frame  3 . The slider  70  functions as the conveying roller operation member moving the conveying roller  20  to the conveying position (first roller position) where the conveying roller  20  contacts the optical disc and to a position (second roller position) that is located away from the conveying position and where the conveying roller  20  is separated from the optical disc. 
       FIGS.  9 A and  9 B  are left side views of the slider  70 , the gears, and the roller bracket  50 . At the left end portion of the bottom frame  3 , the slider  70  can move between a first slide position (first operation member position) and a second slide position (second operation member position) located in front of and away from the first slide position.  FIG.  9 A  depicts a case where the slider  70  is placed in the first slide position, and  FIG.  9 B  depicts a case where the slider  70  is placed in the second slide position located in front of the first slide position. As depicted in  FIG.  9 A , when the slider  70  is in the first slide position, the conveying roller  20  is placed in the conveying position. Further, as depicted in  FIG.  9 B , when the slider  70  is in the second slide position, the conveying roller  20  is placed in the retract position below the conveying position. 
     As depicted in  FIG.  2 B , a front end portion of the slider  70  is fitted inside a guide hole  35  formed at the left end portion (left side wall portion  32 L) of the bottom frame  3 . A guide surface  71  facing forward and obliquely downward is formed at the front end portion of the slider  70 , and as depicted in  FIG.  4   , a guided portion  54  is formed at the left end portion of the roller bracket  50 . The guided portion  54  protrudes leftward from the roller bracket  50 . When the slider  70  moves from the first slide position to the second slide position, inside the bottom frame  3  or inside the guide hole  35 , the guided portion  54  of the roller bracket  50  comes into contact with the guide surface  71  of the slider  70  and is pushed up by the guide surface  71 . At this time, the roller bracket  50  rotates along the axis CA to move, to the retract position, the conveying roller  20  located behind the axis CA (see  FIG.  9 B ). 
     A front end portion of the roller bracket  50  constitutes a shutter portion  55  configured to occlude the insertion port of the optical disc drive  1 . The roller bracket  50  is pushed by the slider  70  and rotated around the axis CA and is thus located in front of the axis CA. At this time, the shutter portion  55  is placed above the conveying roller  20  and blocks the insertion port of the optical disc drive  1 . Thus, when the optical disc is placed on the spindle motor  11 , the user can be prevented from attempting to further insert another optical disc into the insertion port. 
     The conveying mechanism A includes, as the conveying roller position manipulation mechanism that moves the position of the conveying roller  20 , the loading motor  60  and a second transmission mechanism that transmits rotation of the loading motor  60  to the slider  70  used as the conveying roller operation member. As depicted in  FIG.  9 B , inside the slider  70 , formed is an operated portion  72  that is shaped like a rack and that extends along the front-back direction, and the operated portion  72  meshes with the gear  61   g . In the present embodiment, the gears  61   a  to  61   c ,  61   f , and  61   g  correspond to the second transmission mechanism. With the gear  61   g  rotating and with the gear  61  meshed with the operated portion  72 , the slider  70  moves forward or backward. As depicted in  FIGS.  2 B and  7   , at least a part of the loading motor  60  is located in front of the gear  61   g  constituting a back end of the second transmission mechanism. Note that the second transmission mechanism is not limited to the gears and may include belts or the like. 
     Further, the conveying mechanism A includes a distribution mechanism that engages with each of the first transmission mechanism that transmits the rotation of the loading motor  60  to the conveying roller  20  and the second transmission mechanism that transmits the rotation of the loading motor  60  to the slider  70  used as the conveying roller operation member, the distribution mechanism distributing the rotation of the loading motor  60  to the first transmission mechanism and the second transmission mechanism. Thus, the transmission path for the rotation of the loading motor  60  can be restrained from being elongated. In the present embodiment, as depicted in  FIG.  8   , the distribution mechanism includes an intermediate gear  61   c  that is a member different from the gear  61   a  (worm gear) corresponding to a member directly attached to the loading motor  60 . The gear  61   c  used as the distribution mechanism is meshed both with the gear  61   d  included only in the first transmission mechanism and with the gear  61   f  included only in the second transmission mechanism. 
     Further, some of the members constituting the first transmission mechanism are disposed in a first direction with respect to the distribution mechanism, whereas some of the members constituting the second transmission mechanism are disposed in a second direction opposite to the first direction, with respect to the distribution mechanism. As depicted in  FIG.  8   , the gears  61   d  and  61   e , which are included in the members constituting the first transmission mechanism but do not constitute the second transmission mechanism, are disposed in front of the gear  61   c  which constitutes the distribution mechanism, while the gears  61   f  and  61   g , which are included in the members constituting the second transmission mechanism but do not constitute the first transmission mechanism, are disposed behind the gear  61   c . Thus, compared to, for example, a case in which the members constituting only the first transmission mechanism and the members constituting only the second transmission mechanism are arranged ahead of the distribution mechanism in the same direction, the present embodiment allows both paths of the first transmission mechanism and the second transmission mechanism to be shortened. This allows the optical disc drive  1  as a whole to be miniaturized, and enables torque loss caused by an elongated transmission path to be reduced. 
     As depicted in  FIG.  7   , the optical disc drive  1  includes a holder  62  holding the first transmission mechanism, the second transmission mechanism, and the loading motor. The loading motor  60  is fitted into the holder  62 , and the gears  61   c  to  61   g  are supported by the holder  62 . As depicted in  FIGS.  2 B and  7   , while being held by the holder  62 , the loading motor  60  and the gears  61   a  to  61   g  constituting the first and second transmission mechanisms are disposed at an inner left end portion of the bottom frame  3  which is generally shaped like a box. In this regard, the conveying roller  20  is disposed in front of the loading motor  60 , the gears  61   a  to  61   g , and the holder  62 . In other words, the conveying roller  20  is disposed closer to the insertion port for the optical disc than the loading motor  60 , the gears  61   a  to  61   g , and the holder  62  are. Thus, in the vicinity of the insertion port, the optical disc is conveyed backward, facilitating insertion of the optical disc. 
     Further, the first transmission mechanism and the second transmission mechanism are disposed inside the bottom frame  3 , and the slider  70  used as the conveying roller operation member is disposed outside the bottom frame  3 . The slider  70  is disposed on the left of the left side wall portion  32 L of the bottom frame  3  which is generally shaped like a box, and is disposed adjacent to the gears  61   a  to  61   g  across the left side wall portion  32 L. By the slider  60  being disposed outside the bottom frame  3  as described above, when the slider  60  moves in the front-back direction, internal components of the bottom frame  3  can be prevented from interfering with the slider  60 . 
       FIGS.  10 A,  11 , and  12 A  are top views depicting a state in which various members are disposed in the top frame  4 .  FIG.  10 A  depicts a case where no disc is present in the optical disc drive  1 ,  FIG.  11    depicts a case where the optical disc O is placed (inserted) in the insertion port of the optical disc drive  1 , and  FIG.  12 A  depicts a case where the optical disc drive  1  is placed in the drive position. In addition to the loading motor  60  and the gears  61   a  to  61   e  (first transmission mechanism), the conveying roller driving mechanism that rotates the conveying roller  20  includes the switch board  15  and the switch arm  80  which are disposed in the top frame  4 . 
     As depicted in  FIG.  10 A , the switch board  15  is disposed at a position corresponding to a left end portion of the top frame  4  and a back end portion of the top frame  4 . The switch board  15  includes a start switch  15   a  and a stop switch  15   b , which will be described below, respectively disposed at a right edge portion and at a left edge portion of the switch board  15 . The switch board  15  is electrically connected to the loading motor  60  via wiring or the like. The start switch  15   a  and the stop switch  15   b  are configured to control a driving period for the loading motor (the period when the loading motor is to be driven). More specifically, the start switch  15   a  and the stop switch  15   b  are configured to detect the position of the optical disc and to control the rotation of the loading motor  60  according to the detected position of the optical disc. The start switch  15   a  is pressed to start rotation of the loading motor  60  (see  FIG.  11   ). Further, when the stop switch  15   b  is pressed in a state in which the start switch  15   a  is being pressed, the rotation of the loading motor  60  is stopped (see  FIG.  12 A ). 
     As depicted in  FIGS.  2 A and  12 A , the loading motor  60  is disposed at the position where the loading motor  60  is overlaid on the optical disc O placed at the position of the spindle motor  11  as viewed from the direction of the rotation axis (axis CB) of the spindle motor  11 . Thus, compared to, for example, a case in which the loading motor  60  is disposed behind the optical disc O placed at the position of the spindle motor  11 , the present embodiment allows shortening of the path for the first transmission mechanism along which the rotation of the loading motor  60  is transmitted to the conveying roller  20 . This enables reduction in torque loss caused by an elongated transmission path for the rotation of the loading motor  60 . 
     Further, as depicted in  FIG.  12 A , the switch board  15 , equipped with the start switch  15   a  and the stop switch  15   b  configured to control the driving period for the loading motor, is located behind the optical disc O placed at the position of the spindle motor  11  as viewed from the direction of the rotation axis (axis CB) of the spindle motor  11 . Thus, compared to, for example, a case in which the switch board  15  is disposed at the position where the switch board  15  is overlaid on the optical disc O placed at the position of the spindle motor  11 , the present embodiment allows the optical disc drive  1  to be miniaturized in the up-down direction. 
     The switch arm  80  also functions as a centering mechanism B for positioning the optical disc conveyed to the position of the spindle motor  11 . In the present embodiment, one switch arm  80  is provided. The switch arm  80  is disposed at a position corresponding to a right side and a back side on the top frame  4  and has a shape curved along an outer edge of the top frame  4 . One end (front end portion) of the switch arm  80  extends to the insertion port for the optical disc, and the other end (back end portion) of the switch arm  80  extends to the left side and the back side on the top frame  4 . The switch arm  80  includes a supported portion  81  shaped like a tube and attached to the top frame  4 . The switch arm  80  is rotatable around an axis (rotational center axis) extending through the center of the supported portion  81  in the up-down direction. As depicted in  FIG.  12 A , the rotational center axis of the switch arm  80  is disposed at a position corresponding to a right side of a first plane (a plane including a line b-b in  FIG.  12 A ) and to a back side (the side opposite to contact portions  82   a  and  82   b  described below) on a second plane (a plane including a line b′-b′ in  FIG.  12 A ), the first plane extending through the rotational center axis (axis CB) of the spindle motor  11  along the front-back direction, the second plane extending orthogonally to the first plane and through the rotational center axis (axis CB) of the spindle motor  11 . When the rotational center axis of the switch arm  80  is disposed behind the spindle motor  11  as described above, the switch arm  80  can be provided with a certain length from the rotational center axis to a front end, allowing the front end portion of the switch arm  80  to be provided with a certain movable range in the lateral direction. 
     As depicted in  FIG.  3   , a spring  85  is attached to the switch arm  80 . In a top view of the top frame  4  depicted in  FIG.  10 A , the spring  85  biases the switch arm  80  clockwise. Further, the switch arm  80  includes a leaf spring portion  86  contacting an internal structure of the top frame  4 . 
     The front end portion of the switch arm  80  reaches an area located in front of the conveying roller  20  (the opening  41 R formed in the top frame  4 ) inside the top frame  4 . As depicted in  FIG.  3   , the switch arm  80  includes two contact portions  82   a  and  82   b  protruding downward. The contact portion  82   a  is formed at the front end portion of the switch arm  80 , and the contact portion  82   b  is formed between the contact portion  82   a  and the supported portion  81 . Further, openings  42   a  and  42   b  extending obliquely with respect to the lateral direction are formed on the right side of the top frame  4 . The openings  42   a  and  42   b  are formed in juxtaposition across the opening  41 R in the front-back direction. The contact portions  82   a  and  82   b  of the switch arm  80  penetrate, in the up-down direction, the openings  42   a  and  42   b  formed in the top frame  4 . Each of tip portions of the contact portions  82   a  and  82   b  reaches a conveying path which is located inside the bottom frame  3  and through which the optical disc passes. 
     The switch arm  80  includes a switch operation portion  83  formed at a back end portion of the switch arm  80  to operate the start switch  15   a  and the stop switch  15   b . Inside the top frame  4 , the switch operation portion  83  is adjacent to the switch board  15  in the lateral direction. As depicted in  FIG.  10 A , in a case where no optical disc O is present in the optical disc drive  1 , the switch operation portion  83  pushes neither the start switch  15   a  nor the stop switch  15   b . As depicted in  FIG.  11   , in a case where the optical disc O is inserted into the insertion port of the optical disc drive  1 , an edge of the optical disc O pushes the contact portion  82   a  rightward, moving the switch arm  80  counterclockwise with respect to the rotational center axis (the center of the supported portion  81 ). The switch operation portion  83  thus pushes only the start switch  15   a . This starts rotation of the loading motor  60 , transmitting the rotation to the conveying roller  20  via the first transmission mechanism (gears  61   a  to  61   e ). Then, the conveying roller  20  is rotated to convey, toward the position of the spindle motor  11 , the optical disc O placed on the conveying roller  20 . 
     Further, when the optical disc O is conveyed to the position of the spindle motor  11 , the edge of the optical disc O pushes the contact portion  82   b  rightward. Thus, the switch arm  80  further moves counterclockwise with respect to the rotational center axis (the center of the supported portion  81 ), and the switch operation portion  83  pushes both the start switch  15   a  and the stop switch  15   b . Then, the rotation of the loading motor  60  stops, and the rotation of the conveying roller  20  rotating via the first transmission mechanism also stops. The rotation of the loading motor  60  is stopped when the optical disc O is conveyed to the position of the spindle motor  11 , as described above, and power consumption of the optical disc drive  1  can thus be reduced. 
     The conveying roller position manipulation mechanism that moves the position of the conveying roller  20  includes the rotary arm  90  (movable member) disposed in the top frame  4 , in addition to the roller bracket  50 , the loading motor  60 , the gears  61   a  to  61   c ,  61   f , and  61   g  (second transmission mechanism), and the slider  70 . As depicted in  FIG.  3   , the rotary arm  90  includes a base portion  91  shaped like a disc, and is located, inside the top frame  4 , in front of the switch board  15  and adjacent to the switch board  15  in the front-back direction. The rotary arm  90  includes a supported portion  92  shaped like a tube and located at the central position of the base portion  91  and attached to the top frame  4 . The rotary arm  90  is rotatable along a rotational center axis extending in the up-down direction at the center of the supported portion  92 . A spring  96  is attached to the inside of the rotary arm  90 . In a top view ( FIG.  10 A ) of the top frame  4 , the spring  96  biases the rotary arm  90  clockwise with respect to the rotational center axis (the center of the supported portion  92 ). 
       FIG.  13    is a perspective view depicting a back side of the switch arm  80  and the rotary arm  90 . As depicted in  FIG.  13   , a contact portion  93  protruding downward is formed on the base portion  91  of the rotary arm  90  at a position away from the supported portion  92 . Further, as depicted in  FIG.  3   , an opening  43  extending like a circular arc in the lateral direction is formed on the left side of the top frame  4 . The contact portion  93  of the rotary arm  90  penetrates the opening  43  of the top frame  4  in the up-down direction. A tip portion of the contact portion  93  reaches the conveying path which is located inside the bottom frame  3  and through which the optical disc passes. As depicted in  FIG.  13   , the contact portion  93  of the rotary arm  90  is located behind the contact portions  82   a  and  82   b  of the switch arm  80 . In other words, the contact portions  82   a  and  82   b  of the switch arm  80  are located in front of the contact portion  93  of the rotary arm  90 . 
     The rotary arm  90  is moved in response to a collision of the optical disc that approaches the position of the spindle motor  11 . In a top view of  FIG.  11   , during the process of conveying, to the position of the spindle motor  11 , the optical disc O inserted into the insertion port of the optical disc drive  1 , the contact portion  93  formed on the rotary arm  90  is pushed leftward by the edge of the disc, thus rotating the rotary arm  90  counterclockwise with respect to the rotational center axis (the center of the supported portion  92 ). 
     Further, as depicted in  FIG.  3   , the rotary arm  90  is provided with a slot portion  94  extending from an output edge portion (more specifically, a projecting portion  98  described below) of the rotary arm  90  toward the supported portion  92 . As depicted in  FIG.  2 B , the slider  70  includes a cover portion  75  covering a part of the left side wall portion  32 L of the bottom frame  3 , and a shaft portion  76  extending in the up-down direction is formed at a right end portion of the cover portion  75 . An opening  44  extending in the front-back direction is formed on the left side of the top frame  4 , and the shaft portion  76  of the slider  70  penetrates the inside of the opening  44 . In other words, a tip portion of the shaft portion  76  is disposed inside the top frame  4 . 
     As depicted in  FIG.  4   , the shaft portion  76  formed on the slider  70  is fitted inside the slot portion  94  formed in the rotary arm  90 . In this state, counterclockwise rotation of the rotary arm  90  moves the position of the slot portion  94  forward. In this regard, an edge of the slot portion  94  pushes the shaft portion  76  forward, thus moving the slider  70  forward as well. When the slider  70  is in the first slide position depicted in  FIG.  9 A , an operated portion  72  shaped like a rack and formed inside the slider  70  is not meshed with the gear  61   g  constituting the second transmission mechanism. In this regard, the rotary arm  90  is rotated by being pushed by the optical disc inserted into the optical disc drive  1 , and the slot portion  94  of the rotary arm  90  pushes out the shaft portion  76  of the slider  70  forward, bringing the operated portion  72  inside the slider  70  into mesh with the gear  61   g . Subsequently, the slider  70  pushes roller bracket  50  down to place the conveying roller  20  in the retract position. As described above, movement of the slider  70  is started during the process of conveying the optical disc to the position of the spindle motor  11 , and the conveying roller  20  can thus be moved to the retract position after the optical disc is placed on the spindle motor  11 . 
     3. Centering Mechanism 
     Now, description will be given of a configuration of the centering mechanism B that aligns, with the central position (drive position) of the spindle motor  11 , the central position of the optical disc conveyed by the conveying mechanism A.  FIG.  14    is a perspective view of the base frame  2  and the top frame  4 . The centering mechanism B is implemented by the base frame  2  and the switch arm  80  disposed in the top frame  4 . 
     As depicted in  FIG.  14   , the base frame  2  that holds the spindle motor  11  is provided with a plurality of stopper portions  26   a  and  26   b  that contact an outer edge of the optical disc having reached the position of the spindle motor  11  and that restrict backward movement of the optical disc. Each of the stopper portions  26   a  and  26   b  is shaped like a column extending upward from an upper surface of the base frame  2  and is formed integrally with the base frame  2 . By the stopper portions  26   a  and  26   b  being integrally formed on the base frame  2  that holds the spindle motor  11 , as described above, change in the positions of the stopper portions  26   a  and  26   b  relative to the spindle motor  11  can be suppressed, allowing misalignment between the central position of the optical disc and the drive position to be inhibited. Further, as depicted in  FIG.  2 A , the two stopper portions  26   a  and  26   b  are disposed away from each other in the rotating direction of the optical disc. In addition, the two stopper portions  26   a  and  26   b  may be integrally formed on the base frame  2  to which the spindle motor  11  is attached, and may be provided fixedly at predetermined positions with respect to the spindle motor  11 . By the plurality of stopper portions  26   a  and  26   b  being provided as described above, the central position of the optical disc can be placed stably in the drive position. Note that the number of stopper portions integrally formed on the base frame  2  may be one or may be three or more. 
     Further, the centering mechanism B includes the switch arm  80 , used as a bias member, including the contact portions  82   a  and  82   b  which contact the outer edge of the optical disc that moves toward the position of the spindle motor  11 . The switch arm  80  uses the contact portions  82   a  and  82   b  to align the center of the optical disc with the position of the spindle motor  11 . The switch arm  80  functions as a bias member biased by the spring  85  such that the contact portions push the optical disc toward the stopper portions  26   a  and  26   b . The switch arm  80  and the contact portions  82   a  and  82   b  function to allow the central position of the optical disc to be guided to the drive position corresponding to the rotation center of the spindle motor  11 . Further, since the one switch arm  80  is provided in the present embodiment, it is possible to reduce the number of components of the optical disc drive  1  compared to a case in which a plurality of bias members are provided. 
     As depicted in  FIG.  12 A , the contact portions  82   a  and  82   b  formed on the switch arm  80  are disposed on a side opposite to the stopper portions  26   a  and  26   b  across the optical disc having reached the position of the spindle motor  11 . The contact portions  82   a  and  82   b  are disposed on one of the right side and the left side of the first plane (the plane including the line b-b in  FIG.  12 A ) described above. In the present embodiment, the contact portions  82   a  and  82   b  are disposed only on the right side of the first plane described above. Further, the contact portions  82   a  and  82   b  are disposed on a front side of the second plane (the plane including the line b′-b′ in  FIG.  12 A ) described above. 
     In addition, as depicted in  FIG.  2 A , in the base frame  2 , the stopper portion  26   b  is disposed on the other side (the left side in the present embodiment) of the first plane (the plane including a line b-b in  FIG.  2 A ) described above, and the stopper portions  26   a  and  26   b  are each arranged on a back side on the second plane (the plane including the line b′-b′ in  FIG.  12 A ) described above. When the contact portions  82   a  and  82   b  and the stopper portion  26   a  and  26   b  are disposed as described above, the optical disc conveyed to the position of the spindle motor  11  can be pushed in both the front-back direction and the lateral direction, allowing the optical disc to be aligned in these two directions. 
     As described above, during the process in which the optical disc is conveyed toward the position of the spindle motor  11 , the rotary arm  90  is rotated in response to a collision with the optical disc. In this regard, the rotary arm  90  includes a first protruding portion  97   a  as a portion engaged with the switch arm  80 , the first protruding portion  97   a  protruding upward and being provided at an end portion of an arm portion  91   a  extending from the base portion  91  shaped like a disc. The slot portion  94 , the arm portion  91   a , and a second protruding portion  97   b  described below that are formed on the rotary arm  90  are disposed apart from one another in a circumferential direction of the base portion  91  shaped like a disc. 
     As depicted in  FIG.  13   , a groove portion  84  is formed in a lower surface of a back end portion of the switch arm  80 . The switch arm  80  used as a member constituting the centering mechanism B is coupled to the rotary arm  90  via the groove portion  84 . Specifically, the centering mechanism B includes the switch arm  80  used as a member coupled to the rotary arm  90  used as a movable member. The rotary arm  90  is engaged with the switch arm  80  via the first protruding portion  97   a . When the optical disc reaches the position of the spindle motor  11 , the rotary arm  90  moves the switch arm  80  such that contact portions  82   a  and  82   b  of the switch arm  80  move away from the optical disc. When the rotary arm  90  is rotated in response to a collision with the optical disc, the first protruding portion  97   a  of the rotary arm  90  is fitted inside the groove portion  84  of the switch arm  80  to push an edge of the groove portion  84  forward, thus moving the switch arm  80 . Thus, the switch arm  80  moves in a direction (counterclockwise direction in  FIG.  11   ) opposite to the bias direction of the spring  85 , and the contact portions  82   a  and  82   b  formed on the switch arm  80  move away from the optical disc placed at the position of the spindle motor  11  (in the drive position). As depicted in  FIG.  12 A , with the optical disc O placed in the drive position, the contact portions  82   a  and  82   b  are placed away from the edge of the optical disc O. This avoids the contact between the optical disc O placed in the drive position and the contact portions  82   a  and  82   b , allowing smooth rotation of the optical disc O to be achieved. 
     4. Chucking Mechanism 
     Now, description will be given of the chucking mechanism C that fixes the optical disc at the central position of the spindle motor  11  (in the drive position). As depicted in  FIG.  3   , the chucking mechanism C includes the chucking pulley  12 . The chucking pulley  12  is a member fixing the optical disc to the spindle motor  11 , and is movable between a position where the chucking pulley  12  is located above and away from the spindle motor  11  (first pulley position) and a position where the chucking pulley  12  approaches and holds the optical disc between the chucking pulley  12  and the spindle motor  11  (second pulley position). The chucking pulley  12  includes a magnet  13  in an inner central portion of the chucking pulley  12 . Further, a fixing member  14  configured to fix the magnet  13  is attached to the inside of the chucking pulley  12 . The chucking pulley  12  is attracted to the spindle motor  11  by a magnetic force of the magnet  13 . 
       FIG.  10 B  and  FIG.  12 B  are diagrams depicting operations of the chucking mechanism C.  FIG.  10 B  is a cross-sectional view taken along a line b-b in  FIG.  10 A , and  FIG.  12 B  is a cross-sectional view taken along the line b-b in  FIG.  12 A . The chucking pulley  12  depicted in  FIG.  10 A  and  FIG.  10 B  is placed in a first pulley position, and the chucking pulley  12  depicted in  FIG.  12 A  and  FIG.  12 B  is placed in a second pulley position located below and in front of the first pulley position. When the chucking pulley  12  is placed in the second pulley position, the magnetic force is exerted between the chucking pulley  12  and the spindle motor  11  to hold the optical disc therebetween. Thus, the optical disc rotates integrally with the spindle motor  11 . 
     The chucking mechanism C includes a pulley position manipulation mechanism configured to manipulate the position of the chucking pulley  12 . As depicted in  FIGS.  3 ,  10 A, and  12 A , the pulley position manipulation mechanism includes a first check arm  110  (manipulation arm) that engages with the chucking pulley  12  and moves the position of the chucking pulley  12 . Further, the first check arm  110  constituting the pulley position manipulation mechanism and the rotary arm  90  are disposed on a common support board (top frame  4 ), the rotary arm  90  being a movable member rotated in response to a collision with the optical disc and moving the first check arm  110 . Inside the top frame  4 , the first check arm  110  is disposed on the left side of the top frame  4  and in front of the rotary arm  90 . Specifically, the first check arm  110  constituting the pulley position manipulation mechanism and the rotary arm  90  used as a movable member are disposed on a side opposite to (to the left of, in the present embodiment) the switch arm  80  across the first plane (the lines b-b depicted in  FIGS.  10 A and  12 A ) described above. As described above, by the pulley position manipulation mechanism being disposed, inside the top frame  4 , on the side opposite to the switch arm  80 , the inner space of the top frame  4  can effectively be utilized. 
     Further, a second check arm  120  is disposed at the central position of the top frame  4 . The second check arm  120 , along with the first check arm  110 , supports an outer circumferential portion of the chucking pulley  12 . As depicted in  FIG.  3   , an opening  45  is formed at the central position of the top frame  4 . The second check arm  120  is disposed inside the opening  45 . The second check arm  120  includes shaft portions  121 L and  121 R provided at a back end portion of the second check arm  120  and arranged in the lateral direction. The second check arm  120  is rotatable in the up-down direction around an axis CE extending through the center of the shaft portions  121 L and  121 R in the lateral direction. The second check arm is biased upward by a spring not illustrated. 
     The first check arm  110  includes a fan-shaped base portion  111  and a supported portion  112  located at the central position of the fan-shaped base portion  111 . The first check arm  110  is rotatable around an axis CC (see  FIGS.  10 B and  12 B ) as the rotational center axis extending through the center of the supported portion  112  along the up-down direction. Further, a spring  116  is attached to the first check arm  110 . The first check arm  110  is biased counterclockwise around the axis CC by an elastomeric force of the spring  116 . 
     Further, the chucking pulley  12  includes two flange portions  12   a  and  12   b  that are provided at an outer circumferential portion of the chucking pulley  12  and project in a radial direction. The two flange portions  12   a  and  12   b  are spaced apart from each other in the up-down direction. The first and second check arms  110  and  120  respectively include support portions  113  and  122  that support the chucking pulley  12 . As depicted in  FIG.  10 A , the support portion  113  is formed at an end portion of an arm portion  111   a  extending outward from the fan-shaped base portion  111  of the first check arm  110 , the support portion  113  extending backward from the end portion. The support portion  122  is formed on the second check arm  120  and located between the shaft portions  121 L and  121 R in the lateral direction and in front of the axis CE. In a case where the chucking pulley  12  is placed in the first pulley position, the support portions  113  and  122  are placed between the two flange portions  12   a  and  12   b  arranged in the up-down direction, as depicted in  FIG.  10 B . The support portions  113  and  122  are thus caught at the flange portion  12   a . The support portion  113  of the first check arm  110  is caught at a front end of the flange portion  12   a , whereas the support portion  122  of the second check arm  120  is caught at a back end of the flange portion  12   a . Thus, the support portions  113  and  122  support the chucking pulley  12  against gravity and the magnetic force of the magnet  13 . 
     A back end portion of the support portion  122  of the second check arm  120  is provided with a guide wall  122   b  protruding upward from an upper surface  122   a  of the support portion  122  and a slope  122   c  extending forward and downward from the upper surface  122   a . As depicted in  FIG.  10 B , when the chucking pulley  12  is placed in the first pulley position, the chucking pulley  12  is pushed backward by the support portion  113  of the first check arm  100 , and an edge of a back end of the flange portion  12   a  comes into contact with the guide wall  122   b . This enables the chucking pulley  12  to be restrained from moving to behind the support portion  122 , allowing the chucking pulley  12  to be inhibited from coming off from the support portions  113  and  122 . 
     As depicted in  FIG.  10 A , the second check arm  120  includes a left arm portion  123 L extending forward from a left side of the support portion  122  and a right arm portion  123 R extending forward from a right side of the support portion  122 . The left and right arm portions  123 L and  123 R are located away from each other in the lateral direction. A cutout portion  124  is formed between the left and right arm portions  123 L and  123 R and opens downward. The support portion  122  located behind the cutout portion  124  protrudes upward with respect to the left and right arm portions  123 L and  123 R. The chucking pulley  12  is fitted between the left and right arm portions  123 L and  123 R (inside the cutout portion  124 ). The flange portions  12   a  and  12   b  formed in the chucking pulley  12  each have a diameter larger than the width of the cutout portion  124  (see  FIG.  3   ) in the lateral direction, and the flange portions  12   a  and  12   b  are overlaid on the left and right arm portions  123 L and  123 R in the up-down direction. This allows the chucking pulley  12  to be restrained from coming off from the inside of the cutout portion  124  formed in the second check arm  120 . 
     Further, as depicted in  FIG.  10 A , the first check arm  110  includes a projecting portion  114  projecting outward from the fan-shaped base portion  111 . The projecting portion  114  is overlaid on a pressed portion  126  located at a front end portion of the left arm portion  123 L of the second check arm  120 , thus pushing the pressed portion  126  downward. The projecting portion  114  pushes a front end portion (pressed portion  126 ) of the second check arm  120  downward as described above, thus restricting the second check arm  120  from being tilted upward due to the elastomeric force of the spring. As depicted in  FIG.  10 B , in a case where the chucking pulley  12  is placed in the first pulley position, the second check arm  120  is placed along a horizontal plane (a plane perpendicular to the axis CB of the spindle motor  11 ) by the projecting portion  114 . In this case, as depicted in  FIG.  10 B , the support portion  122  of the second check arm  120  is placed in a position (hereinafter referred to as a support position) where the support portion  122  supports the flange portion  12   a  of the chucking pulley  12 , and an upper surface  122   a  of the support portion  122  is placed in a position along the horizontal surface. 
     Further, the first check arm  110  protrudes outward from the fan-shaped base portion  111 , and includes a recessed portion  115  whose center is cut out. The arm portion  111   a  provided with the support portion  113 , the projecting portion  114 , and the recessed portion  115  are disposed apart from one another in the rotating direction of the first check arm  110 . As depicted in  FIG.  12 A , the first check arm  110  used as a member constituting a chucking pulley operation mechanism is coupled to the rotary arm  90  via the recessed portion  115 . In other words, the chucking pulley operation mechanism includes the first check arm  110  used as a member coupled to the rotary arm  90  used as a movable member. More specifically, the recessed portion  115  formed in the first check arm  110  corresponds to the shape of a second protruding portion  97   b  formed on the rotary arm  90 , and the first check arm  110  is directly coupled to the second protruding portion  97   b  of the rotary arm  90  via the recessed portion  115 , and is interlocked with the rotary arm  90 . When the slider  70  is moved to the second slide position to rotate the rotary arm  90  counterclockwise with respect to the rotational center axis (the center of the supported portion  92 ), the recessed portion  115  of the first check arm  110  engages with the second protruding portion  97   b  of the rotary arm  90 . The first check arm  110  also rotates clockwise around the axis CC in such a manner as to be pulled by the second protruding portion  97   b . Thus, the support portion  113  formed on the arm portion  111   a  of the first check arm  110  moves forward and is removed from the flange portion  12   a  of the chucking pulley  12 . 
     As depicted in  FIG.  13   , the rotary arm  90  is provided with a projecting portion  98  projecting outward from an outer edge of the base portion  91 . Further, as depicted in  FIG.  10 A , a projecting portion  125  projecting leftward is formed on a left side surface of the left arm portion  123 L of the second check arm  120 . As depicted in  FIG.  12 A , when the rotary arm  90  rotates counterclockwise, the projecting portion  98  of the rotary arm  90  is overlaid on the projecting portion  125  of the second check arm  120  to push the projecting portion  125  downward. Thus, the second check arm  120  located on the horizontal plane is pushed further downward and tilted downward with respect to the horizontal surface. In this case, the support portion  122  of the second check arm  120  is placed in a position depicted in  FIG.  12 B  (hereinafter referred to as a release position), and the upper surface  122   a  of the support portion  122  is placed in a position along the direction inclined with respect to the horizontal plane. 
     As depicted in  FIG.  12 B , in a case where the support portion  122  is placed in the release position, the upper surface  122   a  of the support portion  122  is inclined with respect to the horizontal plane, and the support portion  113  of the first check arm  110  is located off from the flange portion  12   a  of the chucking pulley  12 . Thus, when the support portion  122  moves to the release position, the flange portion  12   a  moves from the upper surface  122   a  of the support portion  122  to be closer to the spindle motor  11  in such a manner as to slide on the slope  122   c  located in front of the flange portion  12   a . The flange portion  12   a  is thus placed in the second pulley position where the flange portion  12   a  holds the optical disc between the flange portion  12   a  and the spindle motor  11 . At this time, before the chucking pulley  12  is attracted to the spindle motor  11  by the magnetic force of the magnet  13 , the flange portion  12   a  comes into contact with the left and right arm portions  123 L and  123 R of the second check arm  120 . This enables a shock caused when the chucking pulley  12  is attracted to the spindle motor  11  to be reduced, allowing the chucking pulley  12  to be restrained from being moved out of the second pulley position due to the shock. 
     Further, clockwise rotation of the rotary arm  90  in the state depicted in  FIG.  12 A  releases the engagement between the second protruding portion  97   b  of the rotary arm  90  and the recessed portion  115  of the first check arm  110 , leading to counterclockwise rotation of the first check arm  110  due to the elastomeric force of the spring  116 . Then, the support portion  113  of the first check arm  110  pushes backward the chucking pulley  12  placed in the second pulley position. The flange portion  12   a  of the chucking pulley  12  runs onto the slope  122   c  formed on the second check arm  12 , and is placed on the support portion  122 . Thus, the chucking pulley  12  is pushed up from the second pulley position to the first pulley position behind and above the second pulley position, enabling the optical disc to be conveyed (discharged) from the drive position to the outside of the insertion port. As described above, the support portion  122  of the second check arm  120  is movable between the support position depicted in  FIG.  10 B  and the release position depicted in  FIG.  12 B . 
     5. Overall Movement 
     Movement of the mechanisms made when the optical disc is inserted into the insertion port of the optical disc drive  1  will be described. As depicted in  FIG.  11   , in a top view of the top frame  4 , the contact portion  82   a  of the switch arm  80  is pushed rightward by the edge of the optical disc to rotate the switch arm  80  counterclockwise with respect to the rotational center axis (the center of the supported portion  81 ). The switch operation portion  83  formed at the back end portion of the switch arm  80  pushes the start switch  15   a  of the switch board  15 . This starts rotation of the loading motor  60 , rotating the conveying roller  20  via the first transmission mechanism (gears  61   a  to  61   e ) and the gear  24  (see  FIG.  2 B ). In this case, in addition to the gears  61   a  to  61   e  constituting the first transmission mechanism, also the gears  61   f  and  61   g  constituting the second transmission mechanism rotate. In the conveying position, the conveying roller  20  is in contact with a lower edge of the optical disc, and therefore, when the conveying roller  20  constituting the conveying mechanism A rotates, the optical disc is conveyed toward the spindle motor  11 . 
     During the process of conveying the optical disc, the edge of the optical disc comes into contact with the contact portion  93  (see  FIG.  13   ) protruding downward from the rotary arm  90 , and in a top view ( FIG.  11   ) of the top frame  4 , the rotary arm  90  rotates counterclockwise. Thus, a pressed portion  73  of the slider  70  that engages with the slot portion  94  of the rotary arm  90  is pushed forward, and the operated portion  72  (see  FIG.  9 A ) shaped like a rack and formed inside the slider  70  comes into mesh with the gear  61   g  constituting the second transmission mechanism. In  FIG.  9 A , the gear  61   g  is rotated clockwise by rotation of the loading motor  60 , and the operated portion  72  thus comes into mesh with the gear  61   g  to convey the slider  70  to the second slide position located in front of the first slide position (see  FIG.  9 B ). Then, the guide surface  71  formed at the front end portion of the slider  70  comes into contact with the guided portion  54  (see  FIG.  4   ) formed at the left end portion of the roller bracket  50  to push the roller bracket  50  down. Thus, the conveying roller  20  is placed in the retract position located below and away from the conveying path for the optical disc. 
     The switch arm  80  is biased by the elastomeric force of the spring  85  of the switch arm  80 , and the contact portions  82   a  and  82   b  formed on the switch arm  80  thus push the optical disc conveyed to the position of the spindle motor  11 , guiding the central position of the optical disc to the position (drive position) of the rotation axis (axis CB) of the spindle motor  11 . Further, the switch operation portion  83  formed at the back end portion of the switch arm  80  pushes the stop switch  15   b  of the switch board  15 , thus stopping the rotation of the loading motor  60  (see  FIG.  12 A ). 
     In the meantime, during the process in which the slider  70  is conveyed to the second slide position by the loading motor  60  and the second transmission mechanism (gears  61   a  to  61   c  and the gears  61   f  and  61   g ), the rotary arm  90  engaged with the slider  70  via the slot portion  94  rotates further clockwise in a top view of the top frame  4 . Then, as depicted in  FIG.  12 A , the second protruding portion  97   b  of the rotary arm  90  engages with the recessed portion  115  of the first check arm  110 , and the first check arm  110  rotates clockwise. Thus, the support portion  113  of the first check arm  110  comes off from the flange portion  12   a  of the check pulley  12 . Further, the projecting portion  98  of the rotary arm  90  pushes down the projecting portion  125  of the second check arm  120 , and the support portion  122  of the second check arm  120  is tilted downward. Thus, the check pulley  12  supported in the first pulley position is placed in the second pulley position, and the magnetic force is exerted between the magnet  13  and the spindle motor  11  to hold the optical disc between the check pully  12  and the spindle motor  11 . This enables the optical disc to be rotated integrally with the spindle motor  11 . 
     Further, when the optical disc reaches the position of the spindle motor  11 , the first protruding portion  97   a  formed on the rotary arm  90  pushes the edge of the groove portion  84  (see  FIG.  13   ) formed in the switch arm  80 , to separate the contact portions  82   a  and  82   b  of the switch arm  80  from the optical disc. This allows smooth rotation of the optical disc to be achieved. 
     6. Vibration Suppression Mechanism 
     Finally, the vibration suppression mechanism D will be described.  FIG.  15    is an exploded perspective view of the base frame  2 .  FIG.  16 A  is a bottom view of the bottom case  5  constituting the outer case. As depicted in  FIGS.  15  and  16 A , the vibration suppression mechanism D is implemented by a plurality of (three in the present embodiment) first dampers  130  and a plurality of (four in the present embodiment) second dampers  140 . The first and second dampers  130  and  140  include an elastic body such as rubber. 
     As depicted in  FIG.  15   , the first damper  130  has a dual structure including an outer tubular portion  131  shaped like a cylinder and an inner tubular portion  132  that is shaped like a cylinder and that has a diameter smaller than that of the outer tubular portion  131 . The inner tubular portion  132  is disposed at the central position of the inside of the outer tubular portion  131 . A plurality of (six in the present embodiment) spoke portions are formed between the outer tubular portion  131  and the inner tubular portion  132 . The spoke portions are disposed at regular intervals along diameters of the outer edge portion  131  to connect the outer tubular portion  131  and the inner tubular portion  132 . The spoke portions are elastically bent between the outer tubular portion  131  and the inner tubular portion  132  to absorb vibration, thus allowing vibration to be restrained from being transmitted between a member attached to the outer tubular portion  131  and a member attached to the inner tubular portion  132 . 
     As described above, the base frame  2  includes the spindle motor  11  and the optical element corresponding to the optical pickup. The base frame  2  is housed in the inner case including the bottom frame  3  and the top frame  4 . The bottom frame  3  is shaped like a box that is open upward, and supports the conveying roller  20  used as the conveying mechanism A. The base frame  2  is disposed in the bottom frame  3 . In this regard, the base frame  2  is fixed in the inner case (the bottom frame  3  and the top frame  4 ) via the first damper  130 . In the present embodiment, the base frame  2  is fixed to the bottom frame  3  via the first damper  130 . 
     Further, the inner case (the bottom frame  3  and the top frame  4 ) is fixed, via the second damper  140 , in an outer case (the bottom case  5  and the cover  6 ) housing the inner case. As described above, the bottom case  5  is shaped like a box that is open upward similarly to the bottom frame  3 , and the inner case (the bottom frame  3  and the top frame  4 ) is fixed to the bottom case  5 . In the present embodiment, the bottom frame  3  is fixed to the bottom case  5  via the second damper  140 . 
     In many cases, the center of gravity of the optical disc is slightly misaligned with the central position of the optical disc. Thus, when the spindle motor  11  rotates the optical disc, the base frame  2  including the spindle motor  11  vibrates. In this regard, the first dampers  130  and the second dampers  140  are respectively provided in the inner case and in the outer case, allowing vibration of the base frame  2  to be restrained from being transmitted to the outer case, effectively preventing vibration from being transmitted to other components disposed outside. 
     As depicted in  FIG.  15   , a plurality of the first dampers  130  are fitted into a plurality of first-damper-attached portions  27  that are formed in the outer circumferential portion of the base frame  2  and that each have a shape corresponding to the shape of an outer circumferential portion of the first damper  130 . In this regard, the first-damper-attached portion  27  is an arcuate cutout formed in the base frame  2  and has a size enough to enclose half or more of the outer circumferential portion of the first damper  130 . The first dampers  130  are attached to the cutouts in the outer circumferential portion of the base frame  2  as described above, thus eliminating the need to provide arrangement spaces for the first dampers  130  inside the base frame  2 . This allows an increased size of the base frame  2  to be avoided. 
       FIG.  2 C  is a cross-sectional view taken along a line c-c in  FIG.  2 A . As depicted in  FIG.  2 C , the first damper  130  includes a groove portion  131   a  provided in an outer surface of the outer tubular portion  131  along a circumferential direction, and the first-damper-attached portion  27  of the base frame  2  is fitted inside the groove portion  131   a . The groove portion  131   a  is provided in a portion that contacts the first-damper-attached portion  27 , that is, in half or more of the outer circumferential portion of the first damper  130 . Further, the bottom frame  3  includes a first protruding portion  36  (see  FIG.  1   ) protruding upward from the bottom frame  3 . The first protruding portion  36  is fixed to the first damper  130  by being inserted through the inside of the inner tubular portion  132  of the first damper  130 . The first protruding portion  36  is shaped like a tube with an opening at an upper end of the tube, and includes a rivet  135  inserted inside the opening. This allows the first damper  130  to be restrained from coming off from the first protruding portion  36  of the bottom frame  3 . Further, since the first protruding portion  36  includes the opening at the upper end thereof, the rivet  135  can be inserted from above the bottom frame  3 . 
     As described above, the first damper  130  is attached to the base frame  2  in the lateral direction or/and the front-back direction (planar direction), whereas the first damper  130  is attached to the bottom frame  3  in the up-down direction (vertical direction). The first damper  130  is attached in such a manner as to be elastically deformable in the planar direction with respect to the base frame  2 , while the first damper  130  is attached in such a manner as to be elastically deformable in the vertical direction with respect to the bottom frame  3 . This allows vibration of the base frame  2  to be restrained from being transmitted to the bottom frame  3  constituting the inner case. 
     As depicted in  FIG.  1   , the bottom case  5  includes a plurality of second-damper-attached portions  56  to which a plurality of the second dampers  140  are attached. In the present embodiment, the second-damper-attached portion  56  is formed as a circular hole portion and disposed inside a circular depression recessed upward toward the bottom frame  3 . As described above, by the second-damper-attached portion  56  being formed inside the depression in the bottom case  5 , the second damper  140  can be restrained from protruding downward from the bottom case  5 . 
       FIG.  16 B  is cross-sectional view taken along a line b-b in  FIG.  16 A . As depicted in  FIG.  16 B , the second damper  140  includes a groove portion  141   a  provided in an outer surface of an outer tubular portion  141  along the circumferential direction, and an edge of the hole portion corresponding to the second-damper-attached portion  56  of the bottom case  5  is fitted inside the groove portion  141   a . Further, the diameter of a part of the outer tubular portion  141  below the groove portion  141   a  is smaller than the diameter of a part of the outer tubular portion  141  above the groove portion  141   a , and an outer edge of a lower end of the outer tubular portion  141  is inclined upward. The shape of the outer tubular portion  141  enables the second damper  140  to be pushed, from above, inside the hole portion corresponding to the second-damper-attached portion  56  of the bottom case  5 . 
     Further, as depicted in  FIG.  16 B , the bottom frame  3  includes a second protruding portion  37  protruding downward from the bottom frame  3 . The second protruding portion  37  is fixed to the second damper  140  by being inserted through the inside of an inner tubular portion  142  of the second damper  140 . The second protruding portion  37  is shaped like a tube with an opening at a lower end of the tube, and includes a rivet  145  inserted inside the opening. This allows the second damper  140  to be restrained from coming off from the second protruding portion  37  of the bottom frame  3 . Further, since the second protruding portion  37  includes the opening at the lower end thereof, the rivet  145  can be inserted from below the bottom frame  3  and the bottom case  5 . 
     As described above, the second damper  140  is attached to the bottom case  5  in the lateral direction or/and the front-back direction (planar direction), whereas the second damper  140  is attached to the bottom frame  3  in the up-down direction (vertical direction). The second damper  140  is attached in such a manner as to be elastically deformable in the planar direction with respect to the bottom case  5 , while the second damper  140  is attached in such a manner as to be elastically deformable in the vertical direction with respect to the bottom frame  3 . This allows vibration of the inner case including the bottom frame  3  to be restrained from being transmitted to the bottom case  5  constituting the outer case. As described above, the first dampers  130  and the second dampers  140  are respectively provided on the inner side and the outer side of the bottom frame  3 , thus allowing vibration of the base frame  2  to be effectively prevented from being transmitted to the bottom case  5 . 
     7. Effects 
     As described above, the optical disc drive  1  includes the gear  61   c  used as the distribution mechanism that engages with each of the gears  61   a  to  61   e  and each of the gears  61   a  to  61   c ,  61   f , and  61   g . The gears  61   a  to  61   e  are used as the first transmission mechanism that transmit the rotation of the loading motor  60  to the conveying roller  20 . The gears  61   a  to  61   c ,  61   f , and  61   g  are used as the second transmission mechanism that transmit the rotation of the loading motor  60  to the slider  70  used as the conveying roller operation member. The distribution mechanism distributes the rotation of the loading motor  60  to the first transmission mechanism and the second transmission mechanism. The present embodiment provided with the distribution mechanism that distributes the rotation of the loading motor  60  to the two mechanisms as described above can suppress an increased length of the transmission path for the rotation of the loading motor  60 , enabling torque loss caused during the process of transmission of the rotation to be reduced, compared to, for example, a case in which independent paths are provided for the first transmission mechanism that transmits the rotation of the loading motor  60  to the conveying roller  20  and the second transmission mechanism that transmits the rotation of the loading motor  60  to the conveying roller operation member (slider  70 ). 
     Further, the conveying roller  20  includes the left roller  21 L and the right roller  21 R, and the first end portion corresponding to one of the left end portion of the left roller  21 L and the right end portion of the right roller  21 R can move in the up-down direction with respect to the second end portion corresponding to the other end portion, with the relative position between the axis CL and the axis CR unchanged. Thus, even in a case where the position of the optical disc inserted into the insertion port of the optical disc drive  1  is misaligned in the lateral direction, the left end portion of the left roller  21 L or the right end portion of the right roller  21 R moves in the up-down direction, allowing the contact between the optical disc and the left and right rollers  21 L and  21 R to be maintained. Further, compared to, for example, a conveying roller in which the left roller  21 L and the right roller  21 R move independently, the conveying roller  20  has a simple structure, enabling the number of components of the optical disc drive  1  to be reduced. 
     Further, the switch arm  80  used as the bias member constituting the centering mechanism B uses the contact portions  82   a  and  82   b  formed on the switch arm  80 , to push, toward the stopper portions  26   a  and  26   b , the optical disc having reached the position of the spindle motor  11 . Thus, the central position of the optical disc can be aligned with the position (drive position) of the rotational center axis of the spindle motor  11 . Further, one switch arm  80  including the contact portions  82   a  and  82   b  suffices. Thus, compared to, for example, a case in which a plurality of bias members are used to push the optical disc, the present embodiment enables the number of components of the optical disc drive  1  to be reduced. 
     Further, the rotary arm  90  is a movable member moved in response to a collision with the optical disc that approaches the position of the spindle motor  11 , and constitutes the conveying roller position manipulation mechanism that moves the position of the conveying roller  20  via the slider  70  and the roller bracket  50 . Then, at least one of the centering mechanism B and the chucking pulley operation mechanism includes a member coupled to the rotary arm  90  used as a movable member. In the present embodiment, the centering mechanism B and the chucking pulley operation mechanism respectively include the switch arm  80  and the first check arm  110  as members coupled to the rotary arm  90 . As described above, the rotary arm  90  is shared by the conveying roller position manipulation mechanism, the centering mechanism B, and the chucking pulley operation mechanism, and this configuration enables the number of components of the optical disc drive  1  to be reduced compared to a case in which the mechanisms do not share the rotary arm  90 . 
     In addition, the base frame  2  is fixed, via the first damper  130 , in the inner case including the bottom frame  3  and the top frame  4 , and the inner case is fixed in the outer case including the bottom case  5  and the cover  6  and housing the inner case via the second damper  140 . This allows vibration of the base frame  2  to be restrained from being transmitted to the outer case, effectively preventing vibration from being transmitted to other components disposed outside. Further, compared to a case in which the damper is formed in only one of the inner case and the outer case, the present embodiment eliminates the need for an increased size of the first or second damper  130  or  140 , allowing an increased size of the optical disc drive  1  to be avoided. Further, compared to a case in which the second damper  140  is not provided in the outer case, the present embodiment enables the first damper  130  to be miniaturized, allowing for a reduction in misalignment between the base frame  2  and the conveying mechanism A supported by the bottom frame  3 , when the optical disc drive  1  is placed in the vertical orientation (when the optical disc drive  1  is placed such that one of the left side surface and the right side surface of the optical disc drive  1  is disposed above the other). 
     8. Modified Example 
     The present invention is not limited to the optical disc drive  1  described above, and various modifications may be made to the present invention. For example, an aspect of the present invention may include a laterally symmetric structure with respect to the structure of the optical disc drive  1  described above. In other words, the laterally positional relation may be reversed. In this case, the “left,” “right,” “clockwise,” and “counterclockwise” in the description can be respectively replaced with “right,” “left,” “counterclockwise,” and “clockwise.” For example, the loading motor  60 , the gears  24  and  61   a  to  61   g , the gear holder  62 , and the slider  70  that are disposed inside the bottom frame  3  may be disposed on the right side of a plane extending through the rotational center axis (axis CB) of the spindle motor  11  along the front-back direction. Further, movement in the up-down direction may be restricted by the right shaft portion  52 R of the roller bracket  50 , whereas movement in the up-down direction may be permitted by the left shaft portion  52 L of the roller bracket  50 . In addition, inside the top frame  4 , the switch board  15  and the first check arm may be disposed on the right side, whereas the switch arm  80  may be disposed on the left side. The contact portions  82   a  and  82   b  formed on the switch arm  80  may be disposed exclusively on the left side of the plane extending through the rotational center axis (axis CB) of the spindle motor  11  along the front-back direction. 
     Further, at least only one of the centering mechanism B and the chucking pulley operation mechanism may include the member coupled to the rotary arm  90  (movable member constituting the conveying roller position manipulation mechanism). This configuration also enables the number of components of the optical disc drive  1  to be reduced compared to a case in which the centering mechanism B and the chucking pulley operation mechanism do not share the rotary arm  90 .