Patent Publication Number: US-6904844-B2

Title: Printing plate removing/supplying device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 USC 119 from Japanese Patent Application No. 2003-83392, the disclosure of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a printing plate removing/supplying device which removes a predetermined printing plate from plural cassettes in which printing plates are respectively accommodated, and conveys and supplies the predetermined printing plate to a section-to-be-supplied-to, which is a subsequent process. 
     2. Description of the Related Art 
     A technique in which, by using a printing plate (e.g., a PS plate, a thermal plate, a photopolymer plate) in which a recording layer (photosensitive layer) is provided on a support, an image is recorded directly by a laser beam or the like onto the photosensitive layer of the printing plate, has come to be developed as a printing plate exposing device. With this technique, it is possible to quickly record an image onto a printing plate. 
     In an automatic printing plate exposing device using the technique of recording images on printing plates, printing plates are removed one-by-one from a cassette in which a plurality of the printing plates are stacked, and are fed in to an exposure section. 
     Printing plates are classified into plural types in accordance with their size, photosensitizing method, material, and the like. Generally, a single type of printing plate is accommodated in any given cassette. In a state in which plural cassettes are stacked one above another in plural levels, the cassettes are accommodated within a cassette stocker portion (accommodating portion) and are supported on rails which are fixed to the inner walls of the cassette stocker portion. Refer to, for example, Japanese Patent Application Laid-Open (JP-A) No. 2000-351460. 
     At the time of refilling and loading in printing plates, side surface covers of the cassette stocker portion are opened to the left and the right, a cassette is pulled out horizontally along the rails of the cassette stocker portion and rails fixed to the side surface covers, and printing plates are loaded into the cassette. 
     Therefore, when setting the automatic printing plate exposing device, it is necessary to ensure space for the pulling-out of the cassettes (space for opening and closing the side surface covers). A problem arises in that ultimately a large space for placement of the device is needed. For example, in a case in which the size of the largest printing plate is 1160 mm by 940 mm, the space needed for pulling out the cassette is about 1300 mm by 1100 mm. 
     Further, the cassette which is pulled out to the exterior of the cassette stocker portion is supported on rails which are fixed to the side surface covers. However, the printing plates are heavy. For example, the total weight of 100 of the largest printing plates is 100 kg. The rigidity of the side surface covers and the members supporting the side surface covers (hinges or the like) must be made to be high, which results in the cost of the device increasing. 
     In addition, because the cassettes are accommodated in plural levels in a state in which one is disposed above another, when the device is set such that the height which makes the printing plate loading work easy is the height of the uppermost cassette, a problem arises in that the workability at the time of loading printing plates into the lower cassettes is poor. 
     SUMMARY OF THE INVENTION 
     In view of the aforementioned, an object of the present invention is to provide a printing plate removing/supplying device which results in less space needed for placement of the device, a lowering of the costs of the device, and improved workability at the time of loading printing plates. 
     In order to achieve the above object, a printing plate removing/supplying device relating to a first aspect of the present invention has an accommodating portion, a cover member, a removing portion, a cassette moving mechanism, and a removing/conveying mechanism. There is a loading space in the accommodating portion. An opening is formed at the top end of the loading space. Cassettes are accommodated so as to be stacked one above the other in plural levels in a state of being provided at predetermined intervals. Plural printing plates are loaded and stacked in the cassettes from the upper side thereof. One cassette can be accommodated directly beneath the opening. At the accommodating portion, the printing plates can be loaded from the opening into the cassette which is positioned at the loading space. The cover member is provided at the opening of the accommodating portion, and can open and close the opening. The removing portion is provided adjacent to the accommodating portion. A printing plate removing position is set at the removing portion. The cassette moving mechanism is provided at the removing portion, and, independently of other cassettes, pulls one cassette selected from among the plurality of cassettes out to the removing portion and moves the selected one cassette to the removing position, and is able to move the selected one cassette to the loading space as well. The removing/conveying mechanism is provided at the removing portion, and removes the printing plate from the cassette positioned at the removing position, and conveys and supplies the printing plate to a portion-to-be-supplied-to of a subsequent process. 
     In this printing plate removing/supplying device, the printing plates are accommodated in stacked states in the cassettes, which are disposed one above the other in plural levels in the accommodating portion. One selected cassette among the plurality of cassettes is, by the cassette moving mechanism, pulled-out to the removing portion and moved to the removing position. By the removing/conveying mechanism, a printing plate is removed and is conveyed and supplied to a portion-to-be-supplied-to of the subsequent process. 
     Here, when one of the cassettes among the plural cassettes is empty, i.e., when there is the need to refill printing plates, the empty cassette is moved by the cassette moving mechanism to the loading space of the accommodating portion. Then, due to the cover member, which is provided at the opening of the accommodating portion, being moved, the upper end of the accommodating portion is opened, and the empty cassette, which has been moved to the loading space, is exposed. In this way, printing plates can be loaded (refilled) from above the accommodating portion into the cassette positioned at the loading space. 
     Accordingly, as compared with a case in which a cassette is pulled out horizontally from the accommodating portion and the printing plates are loaded therein, it is not necessary to ensure space for pulling-out of the cassette. Therefore, the space required for placement of the device can be reduced. 
     Moreover, there is no need for members (side surface covers, members for supporting the side surface covers, and the like) for supporting the cassette in the state in which the cassette is pulled out. Therefore, the cost of the accommodating portion can be reduced. 
     In addition, because the printing plates can be loaded into the plural cassettes at the same operational posture (at the same position), the workability at the time of loading the printing plates is improved. 
     When the operation for loading the printing plates into the cassette is completed, the opening of the accommodating portion is closed by the cover member. Then, the cassette is again moved (i.e., is returned) to the predetermined position by the cassette moving mechanism. 
     In this way, in the printing plate removing/supplying device of the first aspect, it is possible to reduce the space required for placement of the device, reduce the cost of the device, and improve the workability at the time of loading the printing plates. 
     In the printing plate removing/supplying device, the cover member may be structured so as to move to open and close the opening, within a range of an interior of the accommodating portion and an interior of the removing portion. 
     In this case, the cover member is moved to open and close the opening within the range of the interior of the accommodating portion and the interior of the removing portion. Namely, in the state in which the cover member has been moved and the opening of the accommodating portion is opened, the cover member is accommodated within the range of the interior of the accommodating portion and the interior of the removing portion. 
     In this way, the cover member does not project out beyond the space in which the printing plate removing/supplying device is placed. Therefore, less space is required. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view showing the overall structure of an automatic printing plate exposing device to which is applied a printing plate removing/supplying device relating to a first embodiment of the present invention. 
         FIG. 2  is a side view showing a cassette stocker portion which is a structural member of the printing plate removing/supplying device relating to the first embodiment of the present invention. 
         FIG. 3  is a side view showing a cassette stocker portion which is a structural member of a printing plate removing/supplying device relating to a second embodiment of the present invention. 
         FIG. 4  is a side view showing a cassette stocker portion which is a structural member of a printing plate removing/supplying device relating to a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The schematic overall structure of an automatic printing plate exposing device  10 , to which a sheet sucking/feeding device  50  relating to a first embodiment of the present invention is applied, is shown in FIG.  1 . 
     The automatic printing plate exposing device  10  is divided into two main sections which are an exposure section  14 , which illuminates a light beam onto an image forming layer of a printing plate  12  so as to expose an image, and a sheet feeding/conveying section  15  which removes the printing plate  12  and conveys the printing plate  12  to the exposure section  14 . The printing plate  12 , which has been subjected to exposure processing by the automatic printing plate exposure device  10 , is fed out to a developing device (not illustrated) which is disposed adjacent to the automatic printing plate exposure device  10 . 
     Structure of Exposure Section 
     The exposure section  14  is structured such that a rotating drum  16 , around whose peripheral surface the printing plate  12  is trained and held, is the main portion of the exposure section  14 . The printing plate  12  is guided by a conveying guide unit  18 , and is fed in from a direction tangent to the rotating drum  16 . The conveying guide unit  18  is structured by a plate supplying guide  20  and a plate discharging guide  22 . Conveying rollers  108  and a guide plate  109  are disposed at the side of the conveying guide unit  18  which side borders on the sheet feeding/conveying section  15 . 
     The relative positional relationship of the plate supplying guide  20  and the plate discharging guide  22  of the conveying guide unit  18  is such that the plate supplying guide  20  and the plate discharging guide  22  form a sideways V shape. The plate supplying guide  20  and the plate discharging guide  22  rotate by predetermined angles around the right end portion sides thereof in FIG.  1 . Due to this rotation, the plate supplying guide  20  can be selectively disposed at a position corresponding to the rotating drum  16  (a position of being disposed in a direction tangent to the rotating drum  16 ), and a position of inserting the printing plate  12  into a puncher  24  which is provided above the rotating drum  16 . The printing plate  12  which has been fed in from the sheet feeding/conveying section  15  is first guided by the plate supplying guide  20  and fed into the puncher  24  where notches for positioning are formed in the leading end of the printing plate  12 . Further, after the printing plate  12  undergoes processing at the puncher  24  as needed, the printing plate  12  is returned to the plate supplying guide  20 . The printing plate  12  is thereby moved to a position corresponding to the rotating drum  16 . 
     The rotating drum  16  is rotated by an unillustrated driving means in a direction in which the printing plate  12  is attached and exposed (the direction of arrow A in FIG.  1 ), and in a direction in which the printing plate  12  is removed (the direction of arrow B in  FIG. 1 ) which is opposite to the attaching/exposing direction. 
     Leading end chucks  26  are mounted to predetermined positions of the outer peripheral surface of the rotating drum  16 . At the exposure section  14 , when the printing plate  12  is to be attached to the rotating drum  16 , first, the rotating drum  16  is stopped at a position (printing plate attaching position) at which the leading end chucks  26  oppose the leading end of the printing plate  12  which has been fed in by the plate supplying guide  20  of the conveying guide unit  18 . 
     An attaching unit  28  is provided in the exposure section  14  so as to oppose the leading end chucks  26  at the printing plate attaching position. Due to extending/retracting rods  28 A of the attaching unit  28  extending and one end sides of the leading end chucks  26  being pressed, the printing plate  12  can be inserted between the leading end chucks  26  and the peripheral surface of the rotating drum  16 . In the state in which the leading end of the printing plate  12  is inserted between the leading end chucks  26  and the rotating drum  16 , the extending/retracting rods  28 A of the attaching unit  28  are pulled back such that their pressing of the leading end chucks  26  is released. In this way, the leading end of the printing plate  12  is nipped and held between the leading end chucks  26  and the peripheral surface of the rotating drum  16 . At this time, the printing plate  12  is positioned due to the leading end thereof abutting positioning pins (not shown) provided on the rotating drum  16 . When the leading end of the printing plate  12  is fixed to the rotating drum  16 , the rotating drum  16  is rotated in the attaching/exposing direction. In this way, the printing plate  12 , which has been fed in from the plate supplying guide  20  of the conveying guide unit  18 , is trained about the peripheral surface of the rotating drum  16 . 
     A squeeze roller  30  is provided at the downstream side, in the attaching/exposing direction (the direction of arrow A in FIG.  1 ), of the printing plate attaching position, in a vicinity of the peripheral surface of the rotating drum  16 . Due to the squeeze roller  30  moving toward the rotating drum  16 , the printing plate  12  which is trained on the rotating drum  16  is pushed toward the rotating drum  16  and is made to fit tightly to the peripheral surface of the rotating drum  16 . 
     Further, a trailing end chuck attaching/detaching unit  32  is disposed in the exposure section  14  in a vicinity of the upstream side of the leading end chucks  26  in the attaching/exposing direction of the rotating drum  16 . At the trailing end chuck attaching/detaching unit  32 , trailing end chucks  36  move along guides which project out toward the rotating drum  16 . When the trailing end of the printing plate  12  which is trained on the rotating drum  16  opposes the trailing end chuck attaching/detaching unit  32 , the trailing end chucks  36  are moved toward the rotating drum  16  and attached to predetermined positions of the rotating drum  16 . In this way, the trailing end of the printing plate  12  is nipped and held between the trailing end chucks  36  and the rotating drum  16 . 
     When the leading end and the trailing end of the printing plate  12  are held at the rotating drum  16 , the squeeze roller  30  is moved away (refer to the chain line in FIG.  1 ). Thereafter, in the exposure section  14 , while rotating the rotating drum  16  at high speed at a predetermined rotational speed, a light beam, which is modulated on the basis of image data, is irradiated from a recording head portion  37  synchronously with the rotation of the rotating drum  16 . In this way, the printing plate  12  is scan-exposed on the basis of the image data. 
     When the scan-exposure of the printing plate  12  has been completed, the rotating drum  16  is temporarily stopped at a position at which the trailing end chucks  36 , which are holding the trailing end of the printing plate  12 , oppose the trailing end chuck attaching/detaching unit  32 . The trailing end chuck attaching/detaching unit  32  removes the trailing end chucks  36  from the rotating drum  16 . In this way, the trailing end of the printing plate  12  is freed. Thereafter, by rotating the rotating drum  16  in the direction of removing the printing plate  12 , the printing plate  12  is expelled, from the trailing end side thereof, to the plate discharging guide  22  of the conveying guide unit  18  along a direction tangent to the rotating drum  16 . Thereafter, the printing plate  12  is conveyed to the developing device which is the subsequent process. 
     Structure of Removing/Conveying Section  15  (Printing Plate Removing/Supplying Device) 
     As shown in  FIG. 1 , the removing/conveying section  15  is structured by a removing portion  17 , and a cassette stocker portion  19  serving as an accommodating portion and provided adjacent to the removing portion  17 . 
     A raising/lowering stand  23  structuring a cassette moving mechanism is provided at the removing portion  17 . The raising/lowering stand  23  is supported by feed screws  25  which also structure the cassette moving mechanism. The raising/lowering stand  23  can be raised or lowered by operation of the feed screws  25 . In this way, the raising/lowering stand  23  can move upward and downward to positions corresponding to respective cassettes  38  of the cassette stocker portion  19  which will be described in detail later. The cassette  38 , which is pulled out horizontally from the cassette stocker portion  19  to the removing portion  17  can be received by the raising/lowering stand  23  and placed on the raising/lowering stand  23 . 
     A “removing position (fixed position in the vertical direction)” of the printing plate  12  by a removing/conveying mechanism  50  which will be described later is set at the removing portion  17  (the position shown in FIG.  1 ). The cassette  38  which is placed on the raising/lowering stand  23  can be positioned at this “removing position” due to the upward movement of the raising/lowering stand  23 . 
     The removing/conveying mechanism  50  is provided at the removing portion  17 . At the removing/conveying section  50 , a plurality of (e.g., nine) suction cups  40  are disposed at predetermined pitch intervals along the transverse direction of the printing plate  12 . Each of the suction cups  40  is supported so as to hang downward from a base point  70 . The base points  70  can move substantially horizontally in the left/right direction in  FIG. 1  along the cassette  38  which is on the raising/lowering stand  23 . Moreover, the base points  70  are rotatable. In this way, after the suction cups  40  suck the printing plate  12 , they rotate 180° while moving horizontally, so as to convey the printing plate  12  while inverting the printing plate  12 . 
     At the removing/conveying mechanism  50 , the suction cups  40  can move to the aforementioned “removing position” which is set at the removing portion  17 . Accordingly, in the state in which the cassette  38  placed on the raising/lowering stand  23  is positioned at the “removing position”, due to the respective suction cups  40  reaching the “removing position”, the suction cups  40  can suck and remove the printing plate  12  from the cassette  38 . 
     Here, when the printing plate  12  is to be taken out from the cassette  38  by the removing/conveying mechanism  50 , the suction cups  40  contact the interleaf sheet  13  which is the uppermost material within the cassette  38 , because the interleaf sheets  13  and the printing plates  12  (whose emulsion surfaces are facing downward) are stacked alternately within the cassette  38 . When suction force is imparted to the suction cups  40  at the point in time when they contact the uppermost interleaf sheet  13 , the suction force is applied to the uppermost interleaf sheet  13 , as well as to the printing plate  12  therebeneath. The interleaf sheet  13  and the printing plate  12  are thereby sucked as a pair or a set together at the same time. 
     After this sucking, the raising/lowering stand  23 , i.e., the cassette  38 , is lowered and withdrawn to a predetermined withdrawn position. In this way, the sucked interleaf sheet  13  and printing plate  12  are “separated (disjoined)” by a separating plate (not illustrated) provided at the cassette  38 , from the interleaf sheets  13  and printing plates  12  which are beneath and other than that sucked interleaf sheet  13  and printing plate  12 . After this separation, the suction cups  40  are inverted and convey the printing plate  12  while moving horizontally. When the suction cups  40  have rotated 180°, in the state shown in  FIG. 1 , the interleaf sheet  13  is at the lower side and the printing plate  12  is at the upper side, and the interleaf sheet  13  and the printing plate  12  are transferred over to conveying rollers  108 . 
     A belt  56  is trained around a roller  107  which is adjacent to a lower roller  108 A of the conveying rollers  108 . The belt  56  is also trained around a right roller  74 A of a pair of rollers  74  which are disposed in a vicinity of the conveying guide unit  18  of the exposure section  14 . A pair of rollers  76  are provided beneath the pair of rollers  74 . The belt  56  is trained around a right roller  76 A of the lower rollers  76 , and along a pair of small rollers  78 . The belt  56  forms a substantially L-shaped loop on the whole, and is driven in the direction of arrow D in FIG.  1 . 
     A belt  80  spans between a left roller  74 B of the upper pair of rollers  74  and a left roller  76 B of the lower pair of rollers  76 . 
     The roller  74 B is a roller which rotates in the direction opposite to the conveying direction. The frictional force between the roller  74 B and the interleaf sheet  13  is great. At times of usual conveying, the roller  74 B is withdrawn beneath the plane of conveying. After the printing plate  12  and the interleaf sheet  13  have passed over the roller  74 B, the roller  74 B is raised, and pulls the interleaf sheet  13  in between the rollers  74  due to frictional force, and then the roller  74 B is withdrawn. The interleaf sheet  13  is fed to the lower pair of rollers  76 , and is discarded (refer to the chain-line arrow E in FIG.  1 ). 
     The printing plate  12  passes through above the upper pair of rollers  74 , and is fed to the plate supplying guide  20  (refer to the solid line arrow F in FIG.  1 ). 
     As shown in  FIG. 2 , in the cassette stocker portion  19 , the plurality of cassettes  38  are accommodated so as to be stacked one above the other in plural levels (five levels in the present embodiment) in the vertical direction at predetermined intervals. The cassettes  38  can be pulled-out horizontally toward the removing portion  17  along unillustrated rails. A plurality of the printing plates  12  are accommodated in the cassettes  38 . The printing plate  12  is structured such that a photosensitive layer (an image recording layer) is formed on a support. The interleaf sheets  13 , which serve as protective sheets for protecting the photosensitive layers of the printing plates, and the printing plates  12 , whose photosensitive layers are facing downward, are accommodated within the cassette  38  in a state of being stacked alternately. 
     The size of the cassette  38  is set in accordance with the size of the largest printing plate  12  (e.g., 1160 mm by 940 mm). When about 100 of the largest printing plates are accommodated, the size of the cassette  38  is set to about, for example, a height of 70 mm, a width of 1300 mm, and a length of 1070 mm. 
     A rectangular opening  150  is formed in the top end of the cassette stocker portion  19  so as to extend substantially entirely thereover. The size (surface area) of the opening  150  is greater than the size of the largest printing plate  12  (e.g., 1160 mm by 940 mm). The largest printing plate  12  passes through the opening  150  by being moved in the direction orthogonal to the plate surface direction (i.e., in the direction of thickness). For example, when the width by length dimensions of the cassette stocker portion  19  are set to 1500 mm by 1200 mm, the width by length dimensions of the opening are set to about 1300 mm by 1070 mm. 
     A loading space  152 , at which one cassette  38  can be accommodated, is provided directly beneath the opening  150  (i.e., above the topmost cassette  38 ). 
     Note that the height of the cassette stocker portion  19  is set to be low (e.g., 800 mm or less). For example, in a case in which there are five cassettes  38  and the height of the space in which each cassette  38  is accommodated is 100 mm and the height of the loading space portion  152  is 100 mm, the height of the cassette stocker portion  19  is set to be 800 mm or less. Therefore, the height of the top portion of the cassette stocker portion  19  (the opening  150 ) is a height which is appropriate for the work of loading the printing plates  12 , and the workability at the time of loading the printing plates  12  is improved. 
     Here, due to the operation of the feed screws  25 , the raising/lowering stand  23  can move to a position corresponding to the loading space  152 . The cassette  38  placed on the raising/lowering stand  23  can be moved to (positioned at) the loading space  152 . When one of the cassettes  38  among the plurality of cassettes  38  is empty (i.e., when refilling of the printing plates  12  therein is required), that cassette  38  is placed on the raising/lowering stand  23 , and is moved to the loading space  152 . 
     Above the loading space  152 , a substantially rectangular flat-plate-shaped sliding cover  154  serving as a cover member is disposed at the opening  150  so as to be parallel to the top edge of the cassette stocker portion  19  (i.e., parallel to the floor). The sliding cover  154  is supported by unillustrated rails which are provided at the side walls of the cassette stocker portion  19  and the removing portion  17 . Due to the sliding cover  154  moving horizontally (in the direction of arrow G in FIG.  2  and the direction of arrow H in  FIG. 2 ) along these rails, the sliding cover  154  can open and close the opening  150  of the cassette stocker portion  19 . 
     The sliding cover  154  is disposed at a position which is lower than the base points  70  of the removing/conveying mechanism  50 . When the sliding cover  154  is moved toward the removing portion  17 , the suction cups  40  are rotated 180° from the “removing position”, and are disposed above the base points  70 . In this way, the sliding cover  154 , which has been moved toward the removing portion  17 , is disposed between the removing/conveying mechanism  50  and the cassette moving mechanism (the raising/lowering stand  23  and the feed screws  25 ). 
     A jagged portion  156  is formed at one edge of the sliding cover  154  (the edge toward the front in the direction orthogonal to the surface of the drawing of FIG.  2 ). A spur gear  158 , which is provided above one end portion of the sliding cover  154  (the left end portion in FIG.  2 ), engages with the jagged portion  156 . The jagged portion  156  is formed so as to correspond to the teeth of the spur gear  158 . The spur gear  158  can rotate relative to the removing portion  17  due to a supporting shaft  160 , which is fit into the center of the spur gear  158 , being rotatably supported at the removing portion  17  (although this structure is not illustrated). 
     A motor  162  serving as a drive source is provided above the spur gear  158 . A rotating shaft  164  of the motor  162  is rotated clockwise (in the direction of arrow CW in  FIG. 2 ) and counterclockwise (in the direction of arrow CCW in  FIG. 2 ) by an unillustrated control circuit provided at the automatic printing plate exposing device  10 , via an unillustrated wire provided at the automatic printing plate exposing device  10 . A belt  166 , which is a power transmitting device, is trained around the rotating shaft  164  of the motor  162  and the supporting shaft  160  of the spur gear  158 . 
     When the rotating shaft  164  of the motor  162  is rotated by the control circuit clockwise in  FIG. 2  (in the direction of arrow CW in FIG.  2 ), the spur gear  158  is rotated clockwise in  FIG. 2  (in the direction of arrow CW in  FIG. 2 ) via the belt  166 . Therefore, the sliding cover  154 , with whose jagged portion  156  the spur gear  158  is engaged, is moved toward the removing portion  17  (see arrow G in FIG.  2 ), and the opening  150  of the cassette stocker portion  19  is opened. 
     When the rotating shaft  164  of the motor  162  is rotated by the control circuit counterclockwise in  FIG. 2  (in the direction of arrow CCW in FIG.  2 ), the spur gear  158  is rotated counterclockwise in  FIG. 2  (in the direction of arrow CCW in  FIG. 2 ) via the belt  166 . Therefore, the sliding cover  154 , with whose jagged portion  156  the spur gear  158  is engaged, is moved toward the cassette stocker portion  19  (see arrow H in FIG.  2 ), and the opening  150  of the cassette stocker portion  19  is closed by the sliding cover  154  (the state shown in FIG.  2 ). 
     Next, operation of the present first embodiment will be described. 
     At the automatic printing plate exposing device  10  having the above-described structure, when the printing plate  12  (and the interleaf sheet  13 ) are to be taken out from the cassette  38 , one of the cassettes  38 , which are placed one above the other in plural levels, is specified. 
     When the cassette  38  is selected (specified), the raising/lowering stand  23  is moved vertically by operation of the feed screws  25 , and is made to stand-by at a position corresponding to the selected one cassette  38 . That selected one cassette  38  is, independently of the other cassettes  38 , pulled-out in the horizontal direction toward the removing portion  17 , and is placed on the raising/lowering stand  23 . Then, that cassette  38  (the raising/lowering stand  23 ) is moved vertically to the “removing position”, the removing/conveying mechanism  50  is operated, the respective suction cups  40  are moved to the “removing position”, and the printing plate  12  within that cassette  38  is sucked by the suction cups  40 . 
     After the sucking by the suction cups  40 , that cassette  38  is, together with the raising/lowering stand  23 , lowered by the feed screws  25 , and is withdrawn to a predetermined withdrawn position beneath. Accompanying this lowering of the cassette  38 , the suction cups  40  suck and lift-up the printing plate  12  together with the uppermost interleaf sheet  13 . 
     In this case, when the sucked interleaf sheet  13  and printing plate  12  move away from the cassette  38 , the interleaf sheet  13  or printing plate  12  therebeneath may stick to the sucked printing plate  12  due to static electricity or sticking caused by a vacuum between the plates themselves. At this time, due to the separating by the separating plate (not illustrated) provided at the cassette  38 , only the uppermost interleaf sheet  13  which is receiving the suction force and the printing plate  12  immediately therebeneath are separated from the other interleaf sheets  13  and printing plates  12  therebeneath, and are removed. 
     After the suction cups  40  of the sucking/conveying mechanism  50  have lifted the printing plate  12  (and the interleaf sheet  13 ) up out of the cassette  38 , the suction cups  40  move horizontally in the direction of the exposure section  14  while being rotated 180° around the base points  70 , and transfer the printing plate  12  (and the interleaf sheet  13 ) to the conveying rollers  108 . 
     After this sucking, separating, and removing by the suction cups  40 , that cassette  38  (the raising/lowering stand  23 ) is raised again to the “removing position” so as to be set in a prepared state. Thereafter, the above-described operations are repeated such that the printing plates  12  are successively sucked and removed from the cassette  38 . 
     The printing plate  12  (and the interleaf sheet  13 ) which have been transferred to the conveying rollers  108  are conveyed toward the exposure section  14  by the conveying rollers  108 . The interleaf sheet  13  is peeled off from the printing plate  12  by the roller  74 B which rotates in the direction opposite to the conveying direction. The peeled-off interleaf sheet  13  is pulled-in between the rollers  74 , is fed to the lower rollers  76 , and is discarded in an unillustrated discard box. 
     The printing plate  12  continues to be conveyed substantially horizontally along the guide plate  109 , and is fed to the plate supplying guide  20 . The printing plate  12  on the plate supplying guide  20  is fed to the rotating drum  16 . The leading end portion of the printing plate  12  is held by the leading end chucks  26 . Due to the rotating drum  16  rotating in this state, the printing plate  12  is tightly trained around the peripheral surface of the rotating drum  16 . Thereafter, due to the trailing end of the printing plate  12  being held by the trailing end chucks  36 , preparations for exposure are completed. 
     In this state, image data is read, and exposure processing by the light beam from the recording head portion  37  is started. The exposure processing is so-called scan exposure in which the recording head portion  37  moves in the axial direction of the rotating drum  16  while the rotating drum  16  is rotated at high speed (main scanning). 
     When the exposure processing is completed, the conveying guide unit  18  is switched (the plate discharging guide  22  is made to correspond to the rotating drum  16 ). Then, the printing plate  12  trained around the rotating drum  16  is discharged out from a direction tangent to the rotating drum  16 . At this time, the printing plate  12  is fed to the plate discharging guide  22 . When the printing plate  12  is fed to the plate discharging guide  22 , the conveying guide unit  18  is switched such that the plate discharging guide  22  is made to correspond to the discharge opening, and the printing plate  12  is discharged out. The developing section is provided in the direction of discharging, and the printing plate  12  is subsequently subjected to developing processing. 
     At the removing/conveying section  15  (the printing plate removing/supplying device) relating to the present embodiment, in the state in which the removing and conveying of the printing plate  12  toward the exposure section  14  is being carried out, the sliding cover  154  is moved to (is positioned at) the cassette stocker portion  19 , and the opening  150  of the cassette stocker portion  19  is closed by the sliding cover  154  (the state shown in FIG.  1 ). 
     Here, in a case in which one of the cassettes  38  among the plurality of cassettes  38  is empty, first, the suction cups  40  are rotated 180° from the “removing position” so as to be disposed above the base points  70 , and the empty cassette  38  is placed on the raising/lowering stand  23  and moved to the loading space  152 . Then, due to the rotating shaft  164  of the motor  162  being rotated clockwise (in the direction of arrow CW in  FIG. 2 ) by the control circuit provided at the automatic printing plate exposing device  10 , the spur gear  158  is rotated clockwise (in the direction of arrow CW in  FIG. 2 ) via the belt  166 . Therefore, due to the sliding cover  154 , whose jagged portion  156  is engaged by the spur gear  158 , being moved toward the removing portion  17  (in the direction of arrow G in FIG.  2 ), the opening  150  of the cassette stocker portion  19  is opened. The empty cassette  38 , which has been moved to (positioned at) the loading space  152 , is exposed. 
     In this way, the printing plates  12  can be loaded (refilled) into the empty cassette  38  positioned at the loading space  152 , from above the cassette stocker portion  19  (i.e., from the opening  150 ). 
     Accordingly, as compared with a structure in which loading of the printing plates  12  is carried out by pulling the cassette  38  out horizontally from the cassette stocker portion, there is no need to ensure space for pulling-out of the cassette  38 . Therefore, ultimately, the space needed for placement of the automatic printing plate exposing device  10  can be reduced. 
     Moreover, there is no need for members (side surface covers, members for supporting the side surface covers, and the like) for supporting the cassette  38  in the state in which the cassette  38  is pulled out. Therefore, the cost of the cassette stocker portion  19  can be reduced. 
     In addition, because the printing plates  12  can be loaded into the plural cassettes  38  at the same operational posture (at the same position), the workability at the time of loading the printing plates  12  is improved. 
     When the operation for loading (refilling) the printing plates  12  into the cassette  38  is completed, after safety has been confirmed, the rotating shaft  164  of the motor  162  is rotated counterclockwise (in the direction of arrow CCW in  FIG. 2 ) by the control circuit provided at the automatic printing plate exposing device  10 . The spur gear  158  is thereby rotated counterclockwise (in the direction of arrow CCW in  FIG. 2 ) via the belt  166 . Therefore, due to the sliding cover  154 , whose jagged portion  156  is engaging with the spur gear  158 , moving toward the cassette stocker portion  19  (in the direction of arrow H in FIG.  2 ), the opening  150  of the cassette stocker portion  19  is closed by the sliding cover  154 . Next, the cassette  38  in the loading space  152  is placed on the raising/lowering stand  23 , and is again moved to a predetermined position by the raising/lowering stand  23  and the feed screws  25 . 
     In this way, in the removing/conveying section  15  (the printing plate removing/supplying device) relating to the present first embodiment, it is possible to reduce the space required for placement of the device, reduce the cost of the device, and improve the workability at the time of loading the printing plates  12 . 
     Moreover, because the structure of the sliding cover  154  which is the cover member is simple, the number of parts is reduced and the cost is reduced. Moreover, adjustment during assembly is easy. 
     In addition, because the sliding cover  154  is structured so as to move horizontally, the load applied to the motor  162  which is the driving source is small and constant. In this way, it is possible to make the motor  162  compact, and to decrease costs. 
     Because the sliding cover  154  is flat-plate-shaped and is easily reinforced, it can be formed by a thin plate, and costs can be decreased. 
     (Second Embodiment) 
     Next, a second embodiment will be described. Structures and operations which are basically the same as those of the above-described first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted. 
     The structure of a cassette stocker portion  170  serving as an accommodating portion relating to the second embodiment of the present invention is shown in side view in FIG.  3 . 
     The cassette stocker portion  170  basically has the same structure as that of the cassette stocker portion  19  relating to the above-described first embodiment. However, at the cassette stocker portion  170 , the cover member is a shutter  172  which is flexible. 
     The end portions of the shutter  172  in the transverse direction thereof (the direction orthogonal to the surface of the drawing of  FIG. 3 ) are fixed to two chains  174  which are provided at the end portions of the cassette stocker portion  170  in the transverse direction thereof (the direction orthogonal to the surface of the drawing of FIG.  3 ). Each of the chains  174  is trained around four sprockets which will be described later and which are rotatably supported, at the inner walls at both sides in the transverse direction of the cassette stocker portion  170 . 
     Here, sprockets  176  are rotatably supported at both sides in the transverse direction of the cassette stocker portion  170 , at the removing portion  17  side end portion of the top end portion of the cassette stocker portion  170 . The chains  174  are trained around these sprockets  176 . At the side of the top end portion of the cassette stocker portion  170  opposite the removing portion  17  side thereof, the chains  174  are trained around sprockets  178  which are rotatably supported at the inner walls at both transverse direction sides of the cassette stocker portion  170 . Sprockets  180  are rotatably supported beneath the sprockets  178  at the inner walls at both transverse direction sides of the cassette stocker portion  170 . The chains  174  are trained around the lower sprockets  180  and sprockets  182  so as to form substantially L-shaped loops on the whole. 
     The sprockets  180  are connected together by a shaft  184 . A motor  186  serving as a drive source is provided beneath one of the sprockets  180  (the sprocket  180  which is illustrated in FIG.  3 ). The motor  186  is fixed to the floor wall of the cassette stocker portion  170 . A rotating shaft  188  of the motor  186  is rotated clockwise (in the direction of arrow CW in  FIG. 3 ) and counterclockwise (in the direction of arrow CCW in  FIG. 3 ) by an unillustrated control circuit provided at the automatic printing plate exposing device  10  and via an unillustrated wire provided at the automatic printing plate exposing device  10 . A belt  190  is trained about the rotating shaft  188  of the motor  186  and the aforementioned one sprocket  180 . 
     Here, in the state in which the opening  150  is closed by the shutter  172  (i.e., in the state shown in FIG.  3 ), when the rotating shaft  188  of the motor  186  is rotated clockwise in  FIG. 3  (in the direction of arrow CW in  FIG. 3 ) by the control circuit, the sprockets  180  are rotated clockwise in  FIG. 3  (in the direction of arrow CW in  FIG. 3 ) via the belt  190 . Therefore, the chains  174  trained around the sprockets  180  are rotated clockwise in  FIG. 3  while being supported by the respective sprockets (the sprockets  176 ,  178 ,  180 ,  182 ). Therefore, the shutter  172  which is fixed to the chains  174  is moved in the direction of arrow J in  FIG. 3 , and is accommodated between the cassettes  38  which are disposed one above the other in plural levels, and the side wall of the cassette stocker portion  170  opposite the removing portion  17  side thereof (i.e., the shutter  172  is taken-up by the sprockets  178 ,  180 ,  182 ). In this way, the opening  150  of the cassette stocker portion  170  is opened. 
     In the state in which the opening  150  of the cassette stocker portion  170  is open, when the rotating shaft  188  of the motor  186  is rotated counterclockwise in  FIG. 3  (in the direction of arrow CCW in  FIG. 3 ) by the control circuit, the sprockets  180  are rotated counterclockwise in  FIG. 3  (in the direction of arrow CCW in  FIG. 3 ) via the belt  190 . Therefore, the chains  174  trained around the sprockets  180  are rotated counterclockwise in  FIG. 3  while being supported by the respective sprockets (the sprockets  176 ,  178 ,  180 ,  182 ). Therefore, the shutter  172  which is fixed to the chains  174  is moved in the direction of arrow K in  FIG. 3 , and is positioned at the opening  150  (the state shown in FIG.  3 ). In this way, the opening  150  of the cassette stocker portion  170  is again closed by the shutter  172 . 
     Next, operation of the cassette stocker portion  170  relating to the second embodiment of the present invention will be described. 
     In the cassette stocker portion  170  relating to the present second embodiment, in the state in which the removing and conveying of the printing plate  12  to the exposure section  14  is being carried out, the opening  150  is in a state of being closed by the shutter  172  (the state shown in FIG.  3 ). 
     Here, when one of the cassettes  38  among the plurality of cassettes  38  is empty, that empty cassette is disposed on the raising/lowering stand  23 , and is moved to the loading space  152 . Due to the sprockets  180  being rotated clockwise in  FIG. 3  by the motor  186 , the chains  174  trained around the sprockets  180  are rotated clockwise in  FIG. 3  while being supported by the respective sprockets (the sprockets  176 ,  178 ,  180 ,  182 ). Therefore, the shutter  172  which is fixed to the chains  174  is moved in the direction of arrow J in  FIG. 3 , and is accommodated between the cassettes  38  which are disposed one above the other in plural levels, and the side wall of the cassette stocker portion  170  opposite the removing portion  17  side thereof. In this way, the opening  150  of the cassette stocker portion  170  is opened. 
     In this way, the printing plates  12  can be loaded (refilled) into the empty cassette  38  positioned at the loading space  152 , from above the cassette stocker portion  170  (i.e., from the opening  150 ). 
     Moreover, there is no need for members (side surface covers, members for supporting the side surface covers, and the like) for supporting the cassette  38  in the state in which the cassette  38  is pulled out. Therefore, the cost of the cassette stocker portion  170  can be reduced. 
     In addition, because the printing plates  12  can be loaded into the plural cassettes  38  at the same operational posture (at the same position), the workability at the time of loading the printing plates  12  is improved. 
     When the operation for loading (refilling) the printing plates  12  into the cassette  38  is completed, after safety has been confirmed, the sprockets  180  are rotated counterclockwise in  FIG. 3  by the motor  186 . Therefore, the chains  174  which are trained around the sprockets  180  are rotated counterclockwise in  FIG. 3  while being supported by the respective sprockets (the sprockets  176 ,  178 ,  180 ,  182 ). In this way, the shutter  172  supported at the respective chains  174  is moved toward the opening  150 , and the opening  150  is again closed by the shutter  172 . 
     In this way, in the removing/conveying section  15  (the printing plate removing/supplying device) relating to the present second embodiment, it is possible to reduce the space required for placement of the device, reduce the cost of the device, and improve the workability at the time of loading the printing plates  12 . 
     Moreover, the shutter  172  which is the cover member is accommodated (taken-up) within the cassette stocker portion  170 . Therefore, the shutter  172  can be opened and closed within the range of the surface area occupied by the cassette stocker portion  170 , and the space needed for the device can be reduced. 
     In addition, there is no need to withdraw the suction cups  40  to above the base points  70  at the time of loading the printing plates  12  into the empty cassette  38 . Therefore, the supplying and conveying of the printing plates  12  to the exposure section  14  can be carried out from the printing plates  12  accommodated in another of the cassettes  38 . 
     (Third Embodiment) 
     Next, a third embodiment will be described. Structures and operations which are basically the same as those of the above-described first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted. 
     The structure of a cassette stocker portion  200  serving as an accommodating portion relating to the third embodiment of the present invention is shown in side view in FIG.  4 . 
     The cassette stocker portion  200  basically has the same structure as that of the cassette stocker portion  19  relating to the above-described first embodiment. However, in the present third embodiment, the cover member is a folding cover  202  which can be folded over. 
     The folding cover  202  has a plate member  204  and a plate member  206 , each of which is shaped as a rectangular, flat plate, and which are formed in the same configurations and to the same dimensions. The plate member  204  and the plate member  206  are both disposed in a state in which their both transverse direction end portions (the both end portions in the direction orthogonal to the surface of the drawing of  FIG. 4 ) are supported at a step  210  which is formed at an opening  208  of the cassette stocker portion  200 . The opening  208  is closed by the plate member  204  and the plate member  206 . The end portions of plate member  204  and the plate member  206 , which end portions oppose one another, are connected by a hinge  212 . The folding cover  202  is structured so as to be able to be folded over via the hinge  212 . 
     A shaft  216  is fixed to an end portion  214  of the plate member  204  (the end portion at the removing portion  17  side in FIG.  4 ). Due to the shaft  216  being rotatably supported at the opening  208  (the top end portion) of the cassette stocker portion  200 , the plate member  204  can rotate around the shaft  216  with respect to the cassette stocker portion  200 . 
     An end portion  218  of the plate member  206  (the end portion at the side opposite the removing portion  17  side in  FIG. 4 ) is supported so as to be able to move along the step  210  formed at the opening  208 . 
     A sprocket  220  and a sprocket  222 , each of which is supported rotatably, are provided at the removing portion  17  side end portion and the end portion opposite the removing portion  17  side, beneath the folding cover  202  at the cassette stocker portion  200 . A chain  224  is trained around the sprocket  220  and the sprocket  222 . A connecting member  219  is provided between the folding cover  202  side portion of the chain  224  (the upper side portion of the chain  224  in  FIG. 4 ) and the end portion  218  of the plate member  206 . The end portion  218  of the plate member  206  and the chain  224  are rotatably connected by this connecting member  219 . 
     Although not illustrated, the sprocket  220 , the sprocket  222 , the chain  224 , and the connecting member  219  are provided at each of the end portions in the transverse direction (the direction orthogonal to the surface of the drawing of  FIG. 4 ) of the cassette stocker portion  200 . The sprockets  222  are connected by an unillustrated shaft. 
     A motor  226  serving as a drive source is disposed beneath the sprocket  222 . A rotating shaft  228  of the motor  226  is rotated clockwise (in the direction of arrow CW in  FIG. 4 ) and counterclockwise (in the direction of arrow CCW in  FIG. 4 ) by an unillustrated control circuit provided at the automatic printing plate exposing device  10  and via an unillustrated wire provided at the automatic printing plate exposing device  10 . Further, a belt  230  is trained around the rotating shaft  228  of the motor  226  and one of the sprockets  222  (the sprocket  222  shown in FIG.  4 ). 
     Here, when the rotating shaft  228  of the motor  226  is rotated counterclockwise in  FIG. 4  (in the direction of arrow CCW in  FIG. 4 ) by the control circuit, the sprockets  222  are rotated counterclockwise in  FIG. 4  (in the direction of arrow CCW in  FIG. 4 ) via the belt  230 . Therefore, the folding cover  202  side portions of the chains  224  which are trained between the sprockets  222  and the sprockets  220  (i.e., the upper side portions of the chains  224  in  FIG. 4 ) are moved toward the removing portion  17  (in the direction of arrow L in FIG.  4 ). The end portion  218  of the plate member  206  connected to the folding cover  202  sides of the chains  224  by the connecting members  219  is moved toward the removing portion  17  (in the direction of arrow L in FIG.  4 ). Therefore, the folding cover  202  is folded over via the hinge  212  (is set in the inverted V shape shown by the two-dot chain line in FIG.  4 ), and the end portion  218  of the plate member  206  approaches the end portion  214  of the plate member  204 . When the end portion  214  of the plate member  204  and the end portion  218  of the plate member  206  have moved so as to abut one another, the folding cover  202  is folded-over via the hinge  212  in a state in which the plate members  204 ,  206  are superposed together in the direction of plate thickness thereof. At this time, at the removing portion  17  side end portion of the cassette stocker portion  200 , the folding cover  202  is in a state of projecting vertically upward with respect to the cassette stocker portion  200 , and the opening  208  of the cassette stocker portion  200  is opened. 
     In this state in which the opening  208  of the cassette stocker portion  200  has been opened, when the rotating shaft  228  of the motor  226  is rotated clockwise in  FIG. 4  (in the direction of arrow CW in  FIG. 4 ) by the control circuit, the sprockets  222  are rotated clockwise in  FIG. 4  (in the direction of arrow CW in  FIG. 4 ) via the belt  230 . Therefore, the folding cover  202  side portions of the chains  224  which are trained around the sprockets  222  and the sprockets  220  (i.e., the upper side portions of the chains  224  in  FIG. 4 ) are moved toward the side opposite the removing portion  17  (i.e., in the direction of arrow M in FIG.  4 ). The end portion  218  of the plate member  206 , which is connected by the connecting members  219  to the folding cover  202  sides of the chains  224 , is moved toward the side opposite the removing portion  17  (i.e., in the direction of arrow M in FIG.  4 ). Therefore, the plate member  204  and the plate member  206  of the folding cover  202 , which is folded over via the hinge  212 , move apart from one another. Then, the plate member  204  and the plate member  206  are supported at the step  210  of the cassette stocker portion  200  and are moved to positions of being lined up horizontally (the state shown in FIG.  4 ). In this way, the opening  208  of the cassette stocker portion  200  is again closed by the folding cover  202 . 
     Next, operation of the cassette stocker portion  200  relating to the third embodiment of the present invention will be described. 
     In the cassette stocker portion  200  relating to the present third embodiment, in the state in which the removing and conveying of the printing plate  12  to the exposure section  14  is being carried out, the opening  208  of the cassette stocker portion  200  is in a state of being closed by the folding cover  202  (the state shown in FIG.  4 ). 
     Here, when one of the cassettes  38  among the plurality of cassettes  38  is empty, that empty cassette  38  is disposed on the raising/lowering stand  23 , and is moved to the loading space  152 . The sprockets  222  are rotated counterclockwise in  FIG. 4  (in the direction of arrow CCW in  FIG. 4 ) by the motor  226 . Therefore, the folding cover  202  side portions of the chains  224  (i.e., the upper side portions of the chains  224  in  FIG. 4 ) are moved toward the removing portion  17  (in the direction of arrow L in FIG.  4 ), and the end portion  218  of the plate member  206  connected to the chains  224  is moved toward the removing portion  17  (in the direction of arrow L in FIG.  4 ). In this way, at the removing portion  17  side end portion of the cassette stocker portion  200 , the folding cover  202  is folded over in a state of projecting vertically upward with respect to the cassette stocker portion  200 , and the opening  208  of the cassette stocker portion  200  is opened. 
     Accordingly, the printing plates  12  can be loaded (refilled) into the empty cassette  38  positioned at the loading space  152 , from above the cassette stocker portion  200  (i.e., from the opening  208 ). 
     Moreover, there is no need for members (side surface covers, members for supporting the side surface covers, and the like) for supporting the cassette  38  in the state in which the cassette  38  is pulled out. Therefore, the cost of the cassette stocker portion  200  can be reduced. 
     In addition, because the printing plates  12  can be loaded into the plural cassettes  38  at the same operational posture (at the same position), the workability at the time of loading the printing plates  12  is improved. 
     When the operation for loading (refilling) the printing plates  12  into the cassette  38  is completed, after safety has been confirmed, the sprockets  222  are rotated clockwise in  FIG. 4  (in the direction of arrow CW in  FIG. 4 ) by the motor  226 . Therefore, the folding cover  202  side portions of the chains  224  (i.e., the upper side portions of the chains  224  in  FIG. 4 ) are moved toward the side opposite the removing portion  17  (in the direction of arrow M in FIG.  4 ), and the end portion  218  of the plate member  206  connected to the chains  224  is moved toward the side opposite the removing portion  17  (in the direction of arrow M in FIG.  4 ). In this way, the plate member  204  and the plate member  206  of the folding cover  202  are supported at the step  210  of the cassette stocker portion  200 , and are moved to positions of being lined up horizontally, and the opening  208  is again closed by the folding cover  202 . 
     In this way, in the removing/conveying section  15  (the printing plate removing/supplying device) relating to the present third embodiment, it is possible to reduce the space required for placement of the device, reduce the cost of the device, and improve the workability at the time of loading the printing plates  12 . 
     Moreover, the opening  208  of the cassette stocker portion  200  is open in a state in which the folding cover  202  projects vertically upward with respect to the cassette stocker portion  200  at the removing portion side end portion of the cassette stocker portion  200 . Therefore, the folding cover  202  can be opened and closed within the range of the surface area occupied by the cassette stocker portion  200 , and less space is required. 
     The plate member  204  and the plate member  206 , which are the structural members of the folding cover  202 , are flat-plate-shaped and are easily reinforced. Therefore, they can be formed by thin plates. As a result, costs can be reduced. 
     As described above, in accordance with the printing plate removing/supplying device of the present invention, less space is needed for placement of the device, the cost of the device is reduced, and the workability at the time of loading printing plates is improved.