Abstract:
A disc picking device having an engaging member for engaging a disc includes: a contact portion having a contact face for contacting an upper face of the disc; an arm which movably supports the engaging member and has the contact portion; and a moving mechanism moving the arm in a contacting direction for contacting the upper face of the disc, wherein the moving mechanism supports the arm such that the contact portion can be moved in a direction opposite to the contacting direction.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a disc picking device which picks a disc by an engaging member. More specifically, the invention relates to a disc picking device capable of appropriately performing the operation of picking the disc without incurring any disc damage or engaging defection of the engaging member and a disc processing apparatus having the disc picking device. 
         [0003]    2. Related Art 
         [0004]    In a disc processing device such as a disc dubbing device, which writes data in multiple discs such as blank CDs and a CD/DVD publisher which can publish a disc using a produced disc by writing data and printing a label, generally, multiple blank discs or recorded discs are loaded into a stacker such that the discs are stacked in a thickness direction. Gripping devices for gripping a disc loaded in a stacker including a configuration in which a disc is gripped by inserting three gripping claws into a center hole of a disc and expanding the gripping claws in a relative diameter direction of the center hole to push the inner circumference face of the center hole are known. 
         [0005]    In Patent Document 1 (U.S. Pat. No. 6,802,070), a CD transporting device is disclosed. In this CD transporting device, a disc is gripped by inserting three gripping pieces (gripping portion) into a center hole of a CD and expanding the gripping pieces in a radial direction to push the inner circumference face of the center hole. 
         [0006]    In order to expand the three gripping pieces in the radial direction, two gripping claws are fixed, and the remaining one gripping piece is moved in a direction away from the two gripping claws, thereby increasing the area of the circumscribed circle of the three gripping pieces. 
         [0007]    In an arm to which the gripping pieces are attached, a position sensor for detecting a surface of a CD is disposed, and the insertion of the three gripping pieces into the center hole of the CD is detected based on the output of the position sensor. 
         [0008]    When insertion of the gripping pieces into the center hole of the disc cannot be precisely detected by the position sensor, there is a possibility that a problem such as a gripping defection and disc damage occurs. For example, when the insertion of the gripping pieces is detected before the gripping pieces are sufficiently inserted into the center hole of the disc due to a manufacture error of the gripping piece, the arm, or the like, due to an attachment error of the position sensor to the arm, or due to a detection error of the position sensor, and the like, so that the insertion is stopped, the disc is not assuredly gripped by the gripping pieces, and accordingly, the disc may fall down while being transported. On the other hand, when the detection of the insertion of the gripping pieces is late, a part such as a hub to which the gripping pieces are attached may collide with an edge portion of the center hole of the disc causing damage the surface of the disc, and in some cases, there is a possibility that the disc is destroyed. 
         [0009]    Accordingly, the non-uniformity of the stop position of the gripping pieces caused by the position sensor needs to be eliminated. It is very difficult, however, to remove the non-uniformity of a normal position of the gripping pieces caused by manufacture errors and attachment errors of the components, a detection error of the position sensor, and the like. 
         [0010]    In Patent Document 2 (JP-A-2003-331479), a clamper base (contact portion) contacting an upper face of a disc is supported to be rotatable with respect to a bracket (arm) lifted by a lifting mechanism in a direction opposite to the insertion direction, and an upper face of the uppermost disc of a disc storage portion is pressed by a spring force of a torsion spring after the clamper contacts the upper face of the disc. 
         [0011]    However, according to the technology disclosed in Patent Document 2, a rotating mechanism should be provided in the bracket to make the bracket thick and heavy, and consequently, the technology is not appropriate for high-speed transport of a disc. 
       SUMMARY 
       [0012]    An advantage of exemplary aspects of the invention is to provide a picking device capable of responding to high speed transport of a disc by making the arm moved by a moving mechanism thin to decrease the weight thereof. The advantage can be attained by at least one of the following aspects: 
         [0013]    A first aspect of the invention provides a disc picking device having an engaging member for engaging a disc comprising; a contact portion having a contact face for contacting an upper face of the disc; an arm which movably supports the engaging member and has the contact portion; and a moving mechanism moving the arm in a contacting direction for contacting the upper face of the disc, wherein the moving mechanism supports the arm such that the contact portion can be moved in a direction opposite to the contacting direction. 
         [0014]    In the picking device described herein, since the arm which has the contact portion for contacting the upper face of the disc is attached to the moving mechanism such that the contact portion can be moved in a direction opposite to the contacting direction, when the contact portion contacts the disc, the movement of the arm is stopped, and only the moving mechanism can move, thereby preventing damage to the disc. In addition, since any moving mechanism for relatively moving the contact portion and the moving mechanism is not required in the vicinity of the contact portion of the arm, the arm can be made thin and light. 
         [0015]    In this context, when the urging member urging the arm such that the contact portion is located in a predetermined position with respect to the moving mechanism is preferably included, the predetermined position can be adequately maintained in spite of any speed variance of the moving mechanism with regard to the weight of the arm. 
         [0016]    In addition, the arm preferably moves parallel to a moving direction with respect to the moving mechanism. As such, the contact portion is moved parallel to the upper face of the disc, and accordingly, the contact portion does not apply a weight biased on one side to the disk. This aspect is especially preferable for a type of a gripping device in which the gripping portion is inserted into the disc center hole while pushing the inner wall of the center hole, since each gripping portion can push the inner wall at the same time, and any biased weight is thus not applied to the disc. 
         [0017]    In addition, in this case, a disc detecting mechanism for detecting a stop position of the contact portion for contacting the disc to be gripped may be mounted in the arm. 
         [0018]    The disc picking device according to an exemplary embodiment of the invention may be used for a disc processing apparatus having a disc storage portion for storing stacked discs including a CD and a DVD, for example, a CD dubbing apparatus or a CD publisher. 
         [0019]    In a picking device according to an exemplary embodiment of the invention, an engaging member is supported by a support part in a movable manner in a direction opposite to the contacting direction, and the movement of the engaging member is continuously blocked by an elastic member. For example, when the engaging member contacts the surface of a disc as the engaging member is inserted into the disc center hole, the elastic member is elastically deformed to reduce the collision force. In addition, the elastic member is elastically deformed, so that the engaging member cannot move further. Accordingly, even when there is a deviation in the stop position of the engaging member in inserting the engaging member, the disc is not damaged. In addition, the insertion amount is set in consideration of the non-uniform stop positions, and accordingly, damage to the disc caused by the gripping claws can be prevented. 
         [0020]    In another exemplary embodiment of the invention, a disc picking device includes a plurality of gripping portions positionable within a center hole of a disc, the gripping portions gripping the disc via the center hole; a contact portion disposed spaced from the gripping portions, the contact portion including a contact face positioned to contact an upper face of the disc; an arm on which the gripping portions are movable supported, wherein the contact portion is attached to the arm; and a movable housing supporting the gripping portions and the contact portion, the housing moving the gripping portions in an inserting direction into the center hole of the disc. The housing supports the contact portion such that the contact portion can be moved in a direction opposite to the inserting direction. 
         [0021]    The present disclosure relates to the subject matter contained in Japanese patent application No. 2006-136171 filed on May 16, 2007, which is expressly incorporated herein by reference in its entirety. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
           [0023]      FIG. 1  is a schematic view showing a configuration of a CD publisher according to an exemplary embodiment of the present invention. 
           [0024]      FIG. 2  is a perspective view showing a detailed example of an external appearance of a CD publisher. 
           [0025]      FIG. 3  is a perspective view of the CD publisher where the doors are opened. 
           [0026]      FIG. 4  is a perspective view showing an internal configuration of the CD publisher. 
           [0027]      FIG. 5  is a perspective view showing a disc moving mechanism of the CD publisher. 
           [0028]      FIG. 6  is an exploded perspective view of a transport arm of the disc moving mechanism. 
           [0029]      FIG. 7  is a side view showing a gripping mechanism of the disc moving mechanism. 
           [0030]      FIG. 8  is a plan view of the gripping mechanism. 
           [0031]      FIGS. 9A and 9B  are a sectional view and a plan view of gripping claws of the gripping mechanism. 
           [0032]      FIGS. 10A and 10B  are a perspective view and an exploded perspective view showing a connection mechanism of a transport arm and a timing belt. 
           [0033]      FIG. 11  is a schematic flowchart showing a disc gripping operation of the disc moving mechanism. 
           [0034]      FIG. 12  is a perspective view showing a printer of a CD publisher. 
           [0035]      FIG. 13  is a plan view showing a printer tray of the printer. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0036]    Hereinafter, an example of a disc processing device including a disc picking device according to an embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0037]    (Whole Configuration) 
         [0038]      FIG. 1  is a schematic view showing a configuration of a CD publisher according to an exemplary embodiment of the present invention. The CD publisher  1  in this example includes a disc storage portion  3  for storing a disc  2  (blank disc  2 A and a recorded disc  2 B) such as a CD or a DVD, a disc drive  4  which records data into the disc  2  and retrieves data from the disc  2 , a label printer  5  for printing a label including a title indicating recorded data, year/month/date of recording, and the like on a label side  2   a  of the disc  2  in which data is recorded, a disc moving mechanism  6  for transporting the disc  2 , and a control unit  7  responsible for controlling other units. The control unit  7  is connected to a higher rank device  8  such as a control server or a personal computer through a communication line including a LAN. From the higher rank device  8 , a disc manufacturing request (data recording request or data rewriting request), a disc publishing request, or the like is input to the control unit  7 . 
         [0039]    The disc  2  is loaded or unloaded by the disc moving mechanism  6  with a disc tray  71  of the disc drive  4  drawn out to a disc replacing position  71 A. The recording or retrieving of data is performed on the disc  2  which has been guided into the disc tray  71  in a processing position  71 B where the disc tray  71  is inserted into the disc drive  4 . 
         [0040]    The label printer  5  is arranged below the disc drive  4  and includes a printer tray  81  for transporting the disc  2 . The printer tray  81  reciprocates between a print position  81 B and a disc replacing position  81 A. The disc  2  is loaded or unloaded by the disc moving mechanism  6  in the disc replacing position  81 A. In this example, the disc replacing position  81 A of the printer tray  81  is right below the disc replacing position  71 A of the disc tray  71  of the disc drive  4 . 
         [0041]    The disc storage portion  3  includes first and second stackers  11  and  12  which store the discs  2  stacked in the thickness direction. In this example, the first stacker  11  and the second stacker  12  are vertically arranged on the same shaft. Generally, the first stacker  11  serves as a blank disc stacker for storing a blank disc  2 A, and the second stacker  12  serves as a recorded disc stacker for storing a recorded disc  2 B. 
         [0042]    A typical operation of the CD publisher  1  for recording a disc is described as follows. When a data recording request is received from the higher rank device  8 , the CD publisher  1  takes out a blank disc  2 A from the first stacker  11  of the disc storage portion  3 , sets the blank disc  2 A in the disc drive  4 , and records record data which is supplied together with the data recording request. Next, the CD publisher  1  transports the recorded disc  2  to the label printer  5  and prints label printing data which is supplied together with the data recording request on a label side  2   a  of the disc  2 . The CD publisher  1  stores the recorded disc  2 B after the printing process in the second stacker  12  of the disc storage portion  3 . When there is a disc publishing request, the corresponding recorded disc  2 B is taken out from the second stacker  12  by the disc moving mechanism  6  and discharged to a disc discharge port  13  ( FIG. 2 ). As a result, the recorded disc  2 B can be taken out from the CD publisher  1 . 
         [0043]    (Detailed Configuration Example of CD Publisher) 
         [0044]    Next, a detailed configuration example of a CD publisher  1  according to an exemplary embodiment of the invention will be described with reference to  FIGS. 2 to 11 . 
         [0045]      FIG. 2  is a perspective view showing an external appearance of the CD publisher  1 . The CD publisher  1  includes a case  31  with doors  32  and  33  which can be opened or closed to the left or right sides attached to a front face of the case  3 . An operation face  34  on which a display lamp, an operation button, and the like are arranged is formed below the doors  32  and  33 , and a disc discharge port  13  is open beside the operation face  34 . 
         [0046]      FIG. 3  is a perspective view of the CD publisher  1  when the doors  32  and  33  are opened. The door  32  on the left side is locked closed, and a personal authorization mechanism, for example, a fingerprint sensor or the like is arranged on the operation face  34 , so that the door  32  is configured to be opened by only an authorized person. Alternatively, the door  32  may be configured to be openable and closable according to a direction from the higher rank device  8 . On the other hand, the door  33  on the right side is opened or closed at a time when an ink cartridge of the label printer  5  is to be replaced. When the door  33  is opened, a cartridge installation unit  36  is exposed. In the example, the cartridge installation unit  36  includes two upper and lower levels. 
         [0047]      FIG. 4  is a perspective view of the CD publisher  1  when the doors  32  and  33  and a part of the case  31  are removed. Referring to  FIGS. 3 and 4 , inside the case  31  of the CD publisher  1 , a blank disc stacker  11  and a recorded disc stacker  12  are vertically disposed on the same shaft in a left side part. The blank disc stacker  11  includes a slide plate  41  which can be extracted horizontally in a forward direction and a pair of left and right casing boards  42  and  43  in the shape of circular arcs which are disposed vertically on the slide plate  41 . A stacker which can receive a disc  2 A from an upper side and store the disc  2 A stacked in a thickness direction is formed by the slide plate  41  and the casing boards  42  and  43 . The operation of storing or supplementing the disc  2 A in or to the blank disc stacker  11  can be simply performed by opening the door  32  and extracting the slide plate  41  in a forward direction. 
         [0048]    The recorded disc stacker  12  in the lower side has the same configuration. The recorded disc stacker  12  includes a slide plate  44  which can be extracted horizontally in a forward direction and a pair of left and right casing boards  45  and  46  in the shape of circular arcs which are disposed vertically on the slide plate  44 . A stacker which can receive a disc  2 B from an upper side and store the disc  2 B stacked on the same shaft is formed by the slide plate  41  and the casing boards  42  and  43 . 
         [0049]    A disc moving mechanism  6  is disposed in the rear side of the blank disc stacker  11  and the recorded disc stacker  12 . The disc moving mechanism  6  includes a chassis  51  vertically attached to the case  31 , a vertical guide shaft  54  vertically extending between horizontal support plate parts  52  and  53 , which are disposed in upper and lower parts of the chassis  51 , and a transport arm  55  attached to the vertical guide shaft  54 . The transport arm  55  can lift along the vertical guide shaft  54  and rotate on the vertical guide shaft  54  to a left or right side. 
         [0050]    In a rear part of a side of the disc moving mechanism  6 , the disc drive  4  is disposed in an upper side, and the label printer  5  is disposed in a lower side. In  FIGS. 3 and 4 , a disc tray  71  of the disc drive  4  in the upper side is in a disc replacing position  71 A in which the disc tray  71  is drawn out forward and the printer tray  81  of the label printer  5  in the lower side is in the disc replacing position  81 A in the front side. The label printer  5  is preferably an ink jet printer, and ink cartridges  82  for each color are used as an ink supplying source. The ink cartridges  82  are installed to the cartridge installation unit  36  from a front side. 
         [0051]    Here, between the each pair of left and right casing boards  42  and  43  and  45  and  46  of the blank disc stacker  11  and the recorded disc stacker  12 , a gap is formed in which the transport arm  55  of the disc moving mechanism  6  can be lifted. In addition, a gap is formed between the stackers  11  and  12  respectively disposed in the upper and lower sides, so that the transport arm  55  can rotate horizontally and locate right above the stackers  11  and  12 . When the disc tray  71  in the upper side is pushed to be inserted into the disc drive  4 , the transport arm  55  of the disc moving mechanism  6  is lowered, so that the printer tray  81  in the disc replacing position can be accessed by the transport arm  55 . Accordingly, the disc  2  can be transported to each part by performing combined operations of lifting and rotating to the left or right side of the transport arm  55 . 
         [0052]    (Disc Moving Mechanism) 
         [0053]      FIG. 5  is a perspective view showing the disc moving mechanism  6 . As described above, the disc moving mechanism  6  includes a chassis  51  vertically attached to the case  31 , and a vertical guide shaft  54  is attached between the horizontal support plate parts  52  and  53  respectively disposed in the upper and lower parts of the chassis  51 . The transport arm  55  is supported by the vertical guide shaft  54  so as to be liftable and rotatable. 
         [0054]    A lifting mechanism of the transport arm  55  includes a motor  56  for lift which is a driving source. The rotation of the motor  56  is configured to be transferred to a driving side pulley  61  through a speed-reducing gear array including a pinion  57  which is attached to an output shaft of the motor, a mixed transfer gear  58 , and a transfer gear  59 . The driving side pulley  61  is supported in a position around an upper part of the chassis  51  so as to be rotatable on a horizontal rotating shaft (not shown). In a position around a lower part of the chassis  51 , a driven side pulley  63  is supported so as to be rotatable on a horizontal rotating shaft  62  like the driving side pulley  61 , and a timing belt  64  extends between the driving side pulley  61  and the driven side pulley  63 . A rear end of the transport arm  55  is connected to one side of left and right belt parts of the timing belt  64  (The structure of the connection part will be described later with reference to  FIG. 10  and other figures). As a result, when the motor  56  is driven, the timing belt  64  moves up and down, and thus the transport arm  55  attached thereto is lifted along the vertical guide shaft  54 . 
         [0055]    A rotating mechanism of the transport arm  55  includes a motor  65  for rotation which is a driving source, and a pinion (not shown) is attached to an output shaft of the motor  65 . The rotation of the pinion is configured to be transferred to a final-stage gear  69  in the shape of a fan through a speed-reducing gear array having two mixed transfer gears  66  and  67 . The final-stage gear  69  in the shape of a fan can rotate to the left or right side around the vertical guide shaft  54 . In addition, a chassis  51  to which components of the lifting mechanism of the transport arm  55  are attached is mounted on the final-stage gear  69 . When the motor  65  is driven, the final-stage gear  69  in the shape of a fan rotates to the left/right side, and accordingly, the chassis  51  which is mounted thereon rotates to the left/right side around the vertical guide shaft  54  as one structure. As a result, the transport arm  55  which is held by the lifting mechanism mounted on the chassis  51  rotates to the left/right side on the vertical guide shaft  54 . 
         [0056]    (Transport Arm and Gripping Mechanism) 
         [0057]      FIG. 6  is an exploded perspective view showing major parts of the transport arm  55 ,  FIG. 7  is a side view showing an internal structure of the transport arm  55 , and  FIG. 8  is a plan view showing the internal structure of the transport arm  55 . 
         [0058]    The transport arm  55  includes a thin and long arm base  55   a  of which a front end part is in the shape of a half circle and an arm case  55   b  in the shape of the same contour, which covers the arm base  55   a . A gripping mechanism  100  for gripping a disc  2  is installed in the arm base  55   a , and the gripping mechanism  100  is covered with the arm case  55   b  not to be seen. Both the arm base  55   a  and the arm case  55   b  are preferably formed by a resin formation process. 
         [0059]    The gripping mechanism  100  includes three gripping claws (gripping member)  101  to  103  in shapes of cylinders which are disposed in the same circle at equal angular intervals therebetween. The gripping claws  101  to  103  are vertically extruded downward through a circular hole  55   c  formed in a front end of the arm base  55   a . The disc  2  can be gripped by inserting the three gripping claws  101  to  103  into the center hole  2   c  of the disc  2  and pushing the gripping claws  101  to  103  outward in a radial direction. 
         [0060]    The gripping claws  101  to  103  are formed under support pins  111  to  113  having diameters larger than those of the gripping claws  101  to  103 . The support pins  111  to  113  extend upward through the circular hole  55   c  of the arm base  55   a . The support pins  111  to  113  are respectively disposed in three rotation plates  121  to  123  which are disposed on a top face of the arm base  55   a . Rotation center shafts  131  to  133  are vertically installed in the arm base  55   a  at equal angular intervals therebetween in a same circle in a status that the rotation center shafts surround the circular hole  55   c . The rotation plates  121  to  123  are supported so as to be rotatable on the rotation center shafts  131  to  133 , respectively. Pins  101   a  to  103   a  in the shapes cylinders to be described later are preferably formed of resin such as POM in the same bodies as the rotation plates  121  to  123 , respectively. 
         [0061]    The rotation plates  121  to  123  includes front and rear arm parts  121   a ,  121   b ,  122   a ,  122   b ,  123   a , and  123   b , respectively, which extend along the arm base  55   a  in an approximate circumference direction of the circular hole  55   c  and support arms  121   c  to  123   c  which are extruded from the center of the rotation toward an inner side of the circular hole  55   c . On rear sides of front ends of the support arms  121   c  to  123   c , the support pins  111  to  113  are vertically fixed, respectively. 
         [0062]    A rear end of the rear arm part  122   b  of the rotation plate  122  is in contact with a front end face of the front arm part  121   a  of the rotation plate  121  so as to be slidable. Likewise, a rear end of the rear arm part  123   b  of the rotation plate  123  is in contact with a front end face of the front arm part  122   a  of the rotation plate  122  so as to be slidable. A rear end of the rear arm part  121   b  of the rotation plate  121  is in contact with a front end face of the front arm part  123   a  of the rotation plate  123  so as to be slidable. Here, the rotation plates  121  to  123  are configured to rotate in the same direction by properly setting inclination angles of the front end faces of the front arm parts  121   a  to  123   a.    
         [0063]    A helical extension spring  124  extends between the front arm part  121   a  of the rotation plate  121  and the front arm part  122   a  of the rotation plate  122 . By the tensile force of the helical extension spring  124 , the rotation plates  121  to  123  are maintained in a contacting status without rattling, and a biasing force is applied to the rotation plate  121  in a direction (direction in which the gripping claws  101  to  103  are widened) denoted by an arrow R 1  shown in  FIG. 8 . 
         [0064]    In this status, a circumscribed circle of the gripping claws  101  to  103  which are respectively attached to the front ends of the support arms  121   c  to  123   c  of the rotation plates  121  to  123  has a diameter larger than an inner diameter of the center hole  2   c  of the disc  2 . In this state, when one rotation plate, for example, the rotation plate  121  is rotated in a direction denoted by an arrow R 2 , the other two rotation plates  122  and  123  rotates by the same angle in the same direction in concert with the rotation of the rotation plate  121 . As a result, the support arms  121   c  to  123   c  of the rotation plates  121  to  123  move toward the center of the circular hole  55   c , and the gripping claws  101  to  103  attached to the front ends thereof can be collected so as to be inserted into the center hole  2   c  of the disc  2 . In this status, when the gripping claws  101  to  103  are inserted into the center hole  2   c  of the disc  2 , and the rotation plates  121  to  123  are rotated in a reverse direction R 1 , the gripping claws  101  to  103  can be pushed outward in a radial direction. As a result, the gripping claws are pushed to the inner circumference  2   d  of the center hole  2   c  of the disc, so that the disc  2  is gripped. 
         [0065]    In the gripping mechanism  100  of this example, the following mechanisms are included for rotating the rotation plates  121  to  123 . An operation arm  121   d  which extends to the opposite side of the support arm  121   c  is formed in the rotation plate  121 . A front end of an arm part  125   a  in one side of an L-shaped link  125  is connected to a front end of the operation arm  121   d  with the front end of the arm part  125   a  being freely rotated. The L-shaped link  125  can be rotated around a bent part, and a front end of the arm part  125   b  in the opposite side is connected to an operation rod  126   a  of an electromagnetic solenoid  126 . When the electromagnetic solenoid  126  is in an “off” status, the operation rod  126   a  is extended as shown in  FIG. 8 . When the electronic solenoid  126  is shifted to an “on” state, the operation rod  126   a  is pulled in against the spring force of a built-in spring to rotate the L-shaped link  125 . The rotation of the L-shaped link  125  is transferred to the rotation plate  121 , the rotation plate  121  is rotated in a direction R 2 , and the other two rotation plates  122  and  123  are rotated by the same angle in the same direction in synchronization with the rotation of the rotation plate. As a result, separation of the gripping claws  101  to  103  can be shrunken. 
         [0066]    As described above, in the gripping device  100  of this example, three gripping claws  101  to  103  are moved in a radial direction to be in a disc open position in which the gripping claws can be inserted into the center hole  2   c  of the disc  2  and a disc gripping position in which the gripping claws are pushed to the inner circumference face  2   d  of the center hole  2   c  of the disc. By acquiring the amounts of strokes of the gripping claws  101  to  103  sufficiently, the gripping claws  101  to  103  can be inserted into the center hole  2   c  of the disc without touching a surface of the disc. Accordingly, it is not required to form long inclination faces vertically in the front ends of the gripping claws  101  to  103  for guiding the disc  2 , and the lengths of the gripping claws  101  to  103  can be shortened to be substantially equal to the thickness of the disc  2 . 
         [0067]    In addition, the rotation plates  121  to  123  disposed in a planar direction can be held to contact with one another, and when one rotation plate  121  is rotated, the other two rotation plates  122  and  123  are configured to rotate by the same angle in the same direction in concert with the rotation of the rotation plate  121 . Accordingly, the rotation mechanism of the rotation plates  121  to  123  can be flattened. In other words, the mechanism for moving the gripping claws  101  to  103  can be formed in a flat configuration. 
         [0068]    As described above, in this example, since the gripping claws  101  to  103  can be shortened, and the mechanism for moving the gripping claws  101  to  103  can be formed in a flat configuration, the gripping device can be made thin. In addition, since the gripping plates  122  and  123  have the same shape, these components can be commonly used. Accordingly, there is an advantage that the manufacturing cost can be reduced. 
         [0069]    (Gripping Claw) 
         [0070]    Next, the gripping claws  101  to  103  in this example will be described with reference to  FIG. 9 .  FIG. 9(   a ) is a sectional view of the gripping claws  101  and  103 , and  FIG. 9(   b ) is a plan view of the gripping claws  101  to  103 . The gripping claws  101  to  103  include pins  101   a  to  103   a  in the shape of a cylinder which extrude downward from lower end faces (contact portion)  111   a  to  113   a  of support pins  111  to  113  and elastic cylinders  101   b  to  103   b  formed of rubber or the like which surround the pins  101   a  to  103   a  concentrically. Under the lower ends of the pins  101   a  to  103   a , heads  101   c  to  103   c  having large diameters for preventing falling-out are formed. 
         [0071]    The circular outer circumference faces  101   d  to  103   d  of the elastic cylinders  101   b  to  103   b  of the gripping claws  101  to  103  are disc contacting faces which can be contacted to the inner circumference face  2   d  of the center hole  2   c  of the disc  2 . The lengths of the shafts of the gripping claws  101  and  102  are configured to be greater than the length of the shaft of the gripping claw  103  and to be at least greater than the thickness of the inner circumference face  2   d  of the disc  2  to be gripped. In this example, the lengths of the elastic cylinders  101   b  and  102   b  of the gripping claws  101  and  102 , as shown in  FIG. 9(   a ), are configured to be a length extending the whole inner circumference face  2   d  of the stacked upper disc  2 ( 1 ) and at least an upper part of the inner circumference face  2   d  of a lower disc  2 ( 2 ). To the contrary, the length of the elastic cylinder  103   b  of the gripping claw  103  is configured to be equal to or less than the thickness of the inner circumference face  2   d  of the disc  2  to be gripped and, in this example, configured to be slightly less than the thickness of the inner circumference face  2   d.    
         [0072]    As shown in  FIG. 9 , the gripping claws  101  to  103  are inserted into a center hole  2   c  of an uppermost disc  2 ( 1 ) among discs piled up in a thickness direction and pushed outward in a radial direction. In other words, disc contacting faces formed with elastic members  101   b  and  102   b  of the long gripping claws  101  and  102  are elastically transformed by being pushed to the inner circumference face  2   d  of the disc center hole  2   c . However, parts  101   e  and  102   e  (only a part  101   e  is shown in the figure) protruded in the disc contacting face from the disc center hole  2   c  to the opposite side are not elastically transformed and are penetrated into the rear side of the disc  2 ( 1 ). In other words, the parts  101   e  and  102   e  penetrate into a gap between the rear side of the upper disc  2 ( 1 ) to be gripped and a front side of a lower disc  2 ( 2 ). In addition, lower ends  101   f  and  102   f  (only a lower end  101   f  is shown in the figure) of the elastic cylinders  101   b  and  102   b  are pushed to an upper part of the inner circumference face  2   d  of the center hole  2   c  of the lower disc  2 ( 2 ). On the other hand, a disc contacting face of the short gripping claw  103  is pushed to only the inner circumference face  2   d  of the center hole of the uppermost disc  2 ( 1 ). 
         [0073]    The upper disc  2 ( 1 ) is gripped by three gripping claws  101  to  103  assuredly. In addition, the upper disc  2 ( 1 ) is assuredly gripped by the elastic transformation of disc contacting faces of two gripping claws  101  and  102 , so that the upper disc  2 ( 1 ) does not also fall off the gripping claws  101  and  102  in the disc thickness direction. Only parts of the disc contacting faces of two long gripping claws  101  and  102  contacts the lower disc  2 ( 2 ), and the width of outer sides of the lower parts  101   f  and  102   f  is about 87% of an inner diameter of the center hole  2   c . Accordingly, when the gripping claws  101  to  103  are lifted, only the upper disc  2 ( 1 ) is lifted. 
         [0074]    When the gripping claws  101  to  103  are pushed in the radial direction, the position of the upper disc  2 ( 1 ) in the disc planar direction is fixed by the three gripping claws, but since the lower disc  2 ( 2 ) contacts only two gripping claws  101  and  102 , the lower disc  2 ( 2 ) is pushed in the disc planar direction by the gripping claws  101  and  102 . Accordingly, the lower disc  2 ( 2 ) slides in a slightly horizontal direction relatively with respect to the upper disc  2 ( 1 ). Although when the upper and lower discs  2 ( 1 ) and  2 ( 2 ) are tightly contacted, the lower disc  2 ( 2 ) slides to penetrate the air between the upper and lower discs  2 ( 1 ) and  2 ( 2 ), and accordingly, the tight contact is alleviated or released. Accordingly, only the upper disc  2 ( 1 ) can be lifted assuredly. 
         [0075]    In addition, there is an advantage that the disc  2  is not damaged when the disc  2  is gripped since disc contacting faces of the three gripping claws  101  to  103  are formed of the elastic cylinders  101   b  to  103   b.    
         [0076]    Generally, the number of gripping claws is three, but the number of the gripping claws may be four or more. When the number of the gripping claws is four or more, the numbers and disposition of long gripping claws and short gripping claws are properly set, for example, by disposing the long gripping claws in an area less than a ½ times the inner circumference face which does not include a diameter of the center hole or the like 
         [0077]    (Disc Detecting Mechanism) 
         [0078]    The gripping device  100  includes a disc detecting mechanism for controlling a stop position (insertion amount) at a time when the gripping claws  101  to  103  are inserted into the center hole  2   c  of the disc  2 . Referring to  FIGS. 6 to 9 , the disc detecting mechanism  140  in this example is equipped with a disc detecting lever  141  and a disc detector  142  including a photo coupler. The disc detecting lever  141  is an L-shaped lever including a main part  141   a  in the shape of a straight line and a front end part  141   b  which bends at a right angle downward from a front end of the main part  141 . A rear end of the main part  141   a  is attached to a top face of the arm base  55   a  where the rear end of the main part  141   a  can be rotated freely in an upper/lower direction. The main part  141   a  of the disc detecting lever  141  is disposed on the top face of the arm base  55   a , and the front end  141   b  of the main part  141   a  protrudes downward from a rear side of an opening part  55   d  through the opening part which is formed on the arm base  55   a . In a side of the main part  141   a , a detection plate  141   c  which is protruded horizontally is formed. The detection area  142   a  of the disc detector  142  is disposed in the moving trajectory of the detection plate  141   c  which is accompanied by the upward/downward movement of the disc detecting lever  141 . 
         [0079]    When the disc  2  is not gripped, the disc detecting lever  141  is maintained horizontally on the arm base  55   a . In this instance, the detection plate  141   c  is positioned within a detection area  142   a  of the disc detector  142  and is in an “off” status in which detection light passing the detection area  142   a  is blocked. As the gripping claws  101  to  103  are inserted into the center hole  2   c  of the disc  2  by lowering the transport arm  55 , a front end part  141   b  of the disc detecting lever  141  contacts the surface of the disc  2 , and the disc detecting lever  141  is lifted in accompaniment with the insertion of the gripping claws  101  to  103 . 
         [0080]    As shown in  FIGS. 7 and 9(   a ), right before the lower end faces  111   a  to  113   a  of the support pins  111  to  113  supporting the gripping claws  101  to  103  contact the surface of the disc  2  after the gripping claws  101  to  103  have been completely inserted into the center hole  2   c  of the disc  2 , the detection plate  141   c  gets off the detection area  142 , and the disc detector  142  is shifted to an “on” position. Accordingly, the insertion of the gripping claws  101  to  103  into the center hole  2   c  of the disc  2  is detected. 
         [0081]    (Connection Mechanism of Transport Arm and Timing Belt) 
         [0082]    When the insertion position of the gripping claws  101  to  103  is controlled by using the detection mechanism  140 , as shown  FIGS. 7 and 9(   a ), there is a case where the inserting operation of the gripping claws  101  to  103  cannot be stopped precisely at a time when the gripping claws  101  to  103  are completely inserted into the center hole  2   c  of the disc  2  due to a manufacture error of the disc detecting lever  141 , an attachment error of the disc detecting lever  141 , an attachment error of the disc detector  142 , a detection error of the disc detector  142 , and the like. When the insertion is not sufficient, the disc  2  cannot be gripped by the gripping claws  101  to  103 , and accordingly there is a possibility that a gripping defect occurs. On the other hand, when the gripping claws  101  to  103  are excessively inserted, the lower end faces  111   a  to  113   a  of the support pins  111  to  113  to which the gripping claws  101  to  103  are attached and the like come to contact the surface of the disc  2  to damage the disc  2 , and there is a possibility that the disc may be destroyed in some cases. In order to prevent this disadvantage, in this example, a connection mechanism having a configuration that the transport arm  55  is connected to a timing belt  64  which is a lifting mechanism through an elastic member is used. 
         [0083]      FIG. 10(   a ) is a partial perspective view showing a connection mechanism part, and  FIG. 10(   b ) is an exploded perspective view of the connection mechanism part. Referring to  FIGS. 7 and 10 , the transport arm  55  is connected to a belt clip  152  which is fixed to a timing belt  64  through a spring member  151 . A top face  153  facing downward and a ground shaft  154  in the shape of a cylinder which extends vertically from the top face  153  downward are formed in the rear end of the arm base  55   a  of the transport arm  55 . The belt clip  152  includes an upper end face  152   a  which can contact to the top face  153  of the arm base side from a lower side, a shaft hole  152   b  which extends from the upper end face  152   a  through the belt clip  152 , and a fixing part  152   c  which is fixedly connected to the timing belt  64 . The shaft hole  152   b  becomes parallel to the vertical guide shaft when the belt clip  152  is fixed to the timing belt  64 . 
         [0084]    The belt clip  152  is attached to a rear end of the arm base  55   a  where the ground shaft  154  passes through the shaft hole  152   b  of the belt clip  152 , and the upper end face  152   a  of the belt clip  152  contacts the top face  153  from the lower side. Accordingly, the transport arm  55  can be moved upward with respect to the belt clip fixed to the timing belt  64  through support parts including the ground shaft  154 , the shaft hole  152   b , the top face  153 , and the upper end face  152   a . In other words, the transport arm  55  can move in a direction that the gripping claws  101  to  103  are pulled up from the center hole  2   c  of the disc  2 . 
         [0085]    A groove  152   d  which receives the spring member  151  from the lower side is formed in a part disposed in a front side from the shaft hole  152   b  on a lower face of the belt clip  152 . The spring member  151  is attached to a spring hanger  155  which is formed in a rear end of the arm base  55   a  and always biases the belt clip  152  upward. Accordingly, the arm base  55   a  is pushed to the belt clip  152  by the spring member  151 , thus the movement of the arm base  55   a  upward is blocked. Although the ground shaft  154  is formed on the transport arm  55  and the shaft hole  152   b  is formed on the belt clip  152  in this embodiment, a shaft may be formed on the belt clip  152  and a shaft hole for receiving the shaft may be formed on the transport arm  55 . 
         [0086]    When the timing belt  64  is driven (see  FIG. 5 ) by a lifting motor  56 , the belt clip  152  fixed to the timing belt  64  lifts in one body. When an excessive load is not applied, the arm base  55   a  lifts along the vertical guide shaft  54  in one body with the belt clip  152  which is fixed to the timing belt  64  by the spring force of the spring member  151 . 
         [0087]    Here, when the transport arm  55  is lowered and the gripping claws  101  to  103  are inserted into the center hole  2   c  of the disc  2 , it is assumed that the lower end faces  111   a  to  113   a  of the support pins  111  to  113  supporting the gripping claws  101  to  103  collide with the surface of the disc  2  before the disc  2  is detected by the above-described disc detecting mechanism  140 . 
         [0088]    In this case, an excessive load applies temporarily to the transport arm  55 , and the spring member  151  is elastically transformed to be pushed in up/down directions. Thus, the collision force is alleviated owing to the elastic transformation of the spring member  151 . Thereafter, when the belt clip  152  is lowered, the transport arm  55  maintains its position without being lowered since the spring member  151  is elastically transformed. As a result, the disadvantage in that the disc  2  is excessively pushed and destroyed or the like can be prevented. 
         [0089]    The amount of insertion of the gripping claws  101  to  103  into the center hole of the disc is configured to be slightly sufficient, for example, with consideration of a detection error (non-uniformity of stop positions of the gripping claws  101  to  103 ) of the disc detecting mechanism  140  caused by a manufacture error, manufacture errors of the components, attachment errors thereof, and the like. Accordingly, the disc gripping defect of the gripping claws  101  to  103  can be prevented. In addition, when the support pins  111  to  113  (gripping members) to which the gripping claws  101  to  103  are attached contact the surface  2   b  of the disc in inserting the gripping claws  101  to  103 , the spring member  151  which is an elastic member is elastically transformed, and accordingly, the collision force applied to the disc  2  is alleviated. In addition, after the support pins  111  to  113  contact the disc  2 , the spring member  151  is elastically transformed to push in the up/down directions, and accordingly, the transport arm  55  does not move further in the insertion direction. As a result, the disc  2  is not damaged by the support pins  111  to  113 . 
         [0090]    As described above, since the transport arm  55  is attached to a timing belt  64  which is a simple moving mechanism movable in a direction opposite to the gripping direction of a disc  2 , a moving mechanism for moving support pins is not required in the vicinity of the support pins  111  to  113  of the transport arm  55 , and accordingly, the vicinity of the support pins  111  to  113  can be formed thin and light. 
         [0091]    Accordingly, since the inertia in moving the transport arm  55  is small, the transport arm can be moved at a high speed, and it is possible to miniaturize the device. 
         [0092]    (Operation of Disc Gripping) 
         [0093]      FIG. 11  is a schematic flowchart showing a disc gripping operation performed by the disc moving mechanism  6  having the above-described structure. 
         [0094]    For example, a case where a blank disc  2 A stored in a blank disc stacker  11  is gripped and lifted to be transported to another part will be described. In this case, the position of the transport arm  55  is determined to be a predetermined position right above the blank disc stacker  11  under the control of the control unit  7 . 
         [0095]    The electronic solenoid  126  of the gripping mechanism  100  which is installed in the transport arm  55  is turned on (step ST 1 ). When the electronic solenoid is shifted to “on”, its operation rod  126   a  is pulled in, the movement of the operation rod  126   a  is transferred to the rotation plate  121  through the L-shaped link  125 , and accordingly, the rotation plate  121  is rotated by a predetermined angle in a direction of arrow R 2  shown in  FIG. 8 . Remaining rotation plates  122  and  123  are rotated by the same angle in the same direction, the gripping claws  101  to  103  which are attached to front ends of the support arms  121   c  to  123   c  of the three rotation plates  121  to  123  respectively move in directions approaching one another, and accordingly, the gripping claws are collected to be inserted into the center hole  2   c  of the disc  2 A. 
         [0096]    Thereafter, the motor  56  for lifting the transport arm is driven to start a lowering operation of the transport arm  55  (step ST 2 ). When the transport arm  55  is lowered to approach an uppermost blank disc  2 A, the detection lever  141  of the disc detecting mechanism  140  which is built in the transport arm  55  contacts a surface of the blank disk  2 A. Then, the detection lever  141  moves relatively upward in accompaniment with the lowering of the transport arm  55 , the detection plate  141   c  of the detection lever  141  gets off the detection area  142   a  of the disc detector  142 , and accordingly, the disc detector  142  is shifted to “on” (step ST 3 ). The transport arm  55  is lowered by a predetermined distance to stop the transport arm  55 , and the gripping claws  101  to  103  of the gripping device  100  disposed in the transport arm  55  are inserted into the center hole  2   c  of the blank disc  2 A (step ST 4 ). When a stepping motor is used as the motor  56  for lifting the transport arm, for example, the position of the transport arm  55  is determined by the number of steps of the stepping motor. 
         [0097]    After the above-described insertion process in which the three gripping claws  101  to  103  are inserted into the center hole  2   c  of the blank disc  2 A to be gripped is completed, the gripping claws  101  to  103  inserted into the center hole  2   c  are pushed outward in a direction of the diameter of the center hole  2   c  to be pushed to the inner circumference face  2   d  of the center hole  2   c . In other words, the electronic solenoid  126  is turned off, so that the operation rod  126   a  is returned to the protrusion position (step ST 5 ). As a result, the rotation plate  121  connected to the operation rod  126   a  through the L-shaped link  125  is rotated in the direction of arrow R 1  shown in  FIG. 8  by the spring force of the helical extension spring  124  to return to its original position. In the linkage of the movement of the rotation plate  121 , the remaining two rotation plates  122  and  123  are rotated by the same angle in the same direction to return to their original positions. Therefore, a disc gripping status in which the gripping claws  101  to  103  attached to the rotation plates  121  to  123  are pushed outward in the direction of the diameter of the center hole and into the inner circumference face  2   d  of the center hole of the blank disc  2 A. 
         [0098]    After the above-described disc gripping process is completed, a disc lifting process in which the gripped blank disc  2 A is lifted by lifting the transport arm  55  via the gripping claws  101  to  103  is performed (steps ST 11  to ST 15 ). 
         [0099]    In the disc lifting process of this example, until the transport arm  55  is lifted by a predetermined distance, that is, until the gripping claws  101  to  103  move by a predetermined distance in a direction opposite to the insertion direction, the transport arm  55  is lifted intermittently. In other words, a lifting operation which lifts the transport arm  55  by a predetermined distance at a predetermined speed, and a stop operation which stops the transport arm  55  for a predetermined time are repeated a predetermined number of times (steps ST 11  to ST 13 ). When the motor  56  for lifting the transport arm is a stepping motor, the lifting distance can be managed by the number of steps of the stepping motor. 
         [0100]    After the intermittent moving process is performed, it is detected whether the blank disc  2 A is gripped and lifted by the gripping claws  101  to  103  based on an output of the disc detecting mechanism  140  (step ST 14 ). When the blank disc  2 A is lifted, the detection lever  141  of the disc detecting mechanism  140  is in a status that the detection lever  141  is moved upward by the lifted blank disc  2 A, and the disc detector  142  is in an “on” status. Accordingly, it can be detected whether the blank disc  2 A is assuredly gripped and lifted by the gripping claws  101  to  103  based on the output of the disc detecting mechanism  140 . 
         [0101]    When the blank disc  2 A is not lifted, the process is returned to the step ST 1  again, and the gripping and lifting operation of the blank disc  2 A is performed again from the start. When the blank disc  2 A is lifted, a high-speed continuous moving process in which the transport arm  55  is lifted continuously to a position of a predetermined height at a speed higher than the lifting speed of the transport arm in the intermittent moving process is performed (step ST 15 ). 
         [0102]    In this example, the transport arm  55  is, at first, lifted intermittently at a low speed. As described above, the transport arm  55  is connected through the spring member  151  to the timing belt  64  which is a driving member of the lifting mechanism. When there are deviations in the insertion stop positions of the gripping claws  101  to  103 , which are determined by the operation of the disc detecting mechanism  140 , the gripping claws  101  to  103  are inserted into the center hole  2   c  of the disc without incurring any damage to the disc  2 A owing to the elastic transformation of the spring member  151 , and the lower end faces  111   a  to  113   a  of the support pins  111  to  113  to which the gripping claws  101  to  103  are attached contact the surface of the disc. 
         [0103]    The transport arm  55  is pushed to the front side of the disc by the spring force of the spring member  151 . In other words, the blank disk  2 A is pushed to the blank disc  2 A in the lower side by the spring force of the spring member  151  from the upper side. When the gripping claws  101  to  103  are pushed in this manner, if the friction force between the upper and lower blank discs  2 A is higher than the pushing force of the gripping claws  101  to  103 , the blank disc  2 A cannot be moved in a horizontal direction. As a result, it is possible that the inner circumference face  2   d  of the center hole  2   c  of the blank disc cannot be gripped assuredly from the inside by the three gripping claws  101  to  103 . 
         [0104]    Particularly in this example, as shown in  FIG. 9 , it is possible that the gripping claws  101  and  102  cannot be opened by pushing the discs in a horizontal direction when long gripping claws  101  and  102  extend to the inner circumference faces of the two discs and the discs are pushed from the up side. 
         [0105]    In order to prevent this disadvantage, when the transport arm  55  is lifted in the gripping operation of this example, at first, an intermittent lifting operation is repeated. The pushing force of the blank disc  2 A is slowly alleviated by repeating slight lifting and stopping operations of the transport arm  55 . When the pushing force applied to the blank disc  2 A is alleviated to some degree or the pushing force disappears, it becomes possible to push out the blank disc  2 A in a horizontal direction by the gripping claws  101  to  103 . As a result, as described with reference to  FIG. 9 , the upper and lower blank discs  2 A are relatively slid by the gripping claws  101  to  103 , and accordingly, only the upper blank disc  2 A is gripped. Since the blank disc  2 A is assuredly gripped by this intermittent moving process, a disadvantage in that the blank disc  2 A falls off or the like while the blank disc  2 A is lifted can be prevented. 
         [0106]    (Detailed Example of Label Printer) 
         [0107]      FIGS. 12 and 13  are a perspective view showing a detailed example of a label printer  5  and a plan view showing a printer tray  81  of the label printer, respectively. Hereinafter, the configuration of the label printer  5  will be described with reference to the figures. 
         [0108]    The label printer  5  includes a chassis  83  and a carriage guide shaft  84  extending horizontally between left and right side plate parts in a rear side of the chassis  83 , so that a head carriage  85  in which an ink jet head (not shown) is built can reciprocate in left/right directions along the carriage guide shaft  84 . A carriage driving mechanism includes a timing belt  86  that extends horizontally in left/right directions and a carriage motor  87  that is used for driving the timing belt  86 . 
         [0109]    The ink jet head which is built in the head carriage  85  has a nozzle face disposed downward, and a printer tray  81  can reciprocate rear side positions of the ink jet head horizontally in front/rear directions. The printer tray  81  has a right end that is supported by a guide shaft  88  extending horizontally in the front/rear directions and a left end that is supported by a guide rail  89  extending horizontally in the front/rear directions such that the guide rail  89  can slide. A driving mechanism of the printer tray  81  has a configuration including a timing belt  90  that extends horizontally in the front/rear directions and a tray motor  91  that is used for driving the timing belt  90 . 
         [0110]    The printer tray  81  includes a shallow depression part  81   a  that is used for loading a disc  2  in a front face of a rectangular shaped plate. A center part of the depression part  81   a  includes three vertical claws  92  to  94  disposed at 60-degree intervals in the same circle. One vertical claw  94  can be moved in a radial direction, and the remaining two vertical claws  92  and  93  are disposed in a fixed position. One vertical claw  94  is configured to be moved by a driving mechanism such as an electronic solenoid that is not shown in the figure. 
         [0111]    When the disc  2  falls from an upper side into the depression part  81   a  with a label side  2   a  up, as shown in  FIG. 13 , three vertical claws  92  to  94  are inserted into a center hole  2   c  of the disc  2 . Thereafter, when the vertical claw  94  is moved slightly outward in a radial direction, the three vertical claws  92  to  94  are pushed to an inner circumference face  2   d  of the center hole  2   c  of the disc  2  from an inner side. Accordingly, the disc  2  is maintained in the printer tray  81 . The printer tray can be moved to a print region of the ink jet head by driving the tray motor  91  to move the printer tray  81  to a rear side along the guide shaft  88 . Thereafter, printing on a print side of the disc  2  can be performed by the ink jet head. 
         [0112]    The present invention is not limited to the above-described embodiments and various modifications thereof can be made. For example, in the above-described exemplary embodiment, all the three gripping claws  101  to  103  are moved in a center side, but only one of the gripping claws may be movable, like the technology disclosed in Patent Document 1, and the gripping portion may push on a spherical surface. 
         [0113]    Although the arm is moved by the moving mechanism having a timing belt in the embodiment as an example, the arm may be moved by a rack gear or a screw. In the exemplary embodiment, an example in which the arm base  55   a  is pushed to the belt clip  152  by the spring member  151  of the torsion spring, so that the movement of the arm base  55   a  is blocked above the belt clip  152 , but only the weight of the arm without the spring may be applied. However, it is preferable to bias using a spring since the arm follows the speed of the belt. The shape of the spring member  151  is not limited, and a compressive spring or a leaf spring may be used as the spring member. 
         [0114]    Although the gripping member is inserted into the center hole of the disc in the embodiment as an example, the disc may be held at its outer circumference or the disc may be picked by suction. The present invention can be applied to various devices in which an upper surface of the disc is pressed.