Abstract:
An unload table ( 50 ) for a plate making machine comprises an unload table proximal segment ( 194 ) proximate the cylindrical surface ( 120 ) of the imaging drum ( 110 ) of the plate making machine. The unload table proximal segment can tilt to receive a printing plate ( 40 ) being unloaded from the imaging drum. In a further embodiment the unload table itself can also tilt about another axis, allowing the unload table and unload table proximal segment to remain clear of any fixtures on the rotating imaging drum, thereby allowing a printing plate imaged on the imaging drum while the unload table and unload table proximal segment are moving in to a unloading orientation. This enhances the throughput of the plate making machine by reducing the total time required for bulky unload tables to reposition and re-orient for unloading of printing plates.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to printing and in particular, to unloading imaged printing plates from a plate making machine. 
       BACKGROUND OF THE INVENTION 
       [0002]    Imagesetters and platesetters are plate making machines employed to expose the substrates that are used in offset printing systems. Imagesetters are typically used to expose the film that is then used to expose and make the plates for the printing system. Platesetters are used to directly expose the plates, typically using arrays of digitally controlled lasers. 
         [0003]    In the case of platesetters, the plates are typically large substrates coated with photosensitive or thermally-sensitive emulsion layers. For large run applications, the plates are typically fabricated from aluminum, though plates made from other materials are also available for smaller runs. 
         [0004]    Platesetters of the computer-to-plate variety are used to render digitally stored print image content onto these printing plates. Typically, a computer system is used to drive an imaging engine of the platesetter. The imaging engine selectively exposes the emulsion on the plates. In present generation machines this operation is typically performed using digitally controlled laser arrays. After this exposure, the emulsion is developed and either the exposed or the unexposed emulsion is removed, thereby producing a printing master. During the printing process, ink will selectively adhere to the surface of the plate in either the exposed or the unexposed areas to transfer the inked image to a print medium. 
         [0005]    Platesetters typically operate in commercial environments where throughput is a critical parameter. This throughput is often used as the criteria for selecting between the various commercially available systems and is largely determined by the cycle time required: to load the substrate into the imaging engine; for the scanner of the imaging engine to expose the substrate; and to unload the substrate. Most conventional systems expose the media by scanning. In a common implementation, the plate or film media is fixed to the outside or inside of a drum and then scanned with a laser source in a raster fashion. The laser&#39;s dot is moved longitudinally parallel to the axis of the drum in what is known as the “subscan direction,” while the drum is rotated under the imaging dot, thereby moving the exposing beam in the “mainscan direction.” As a result, by modulating the laser, the substrate is selectively exposed in a continuous helical scan. 
         [0006]    The typical approach to reducing the cycle time of the imaging engine focuses on decreasing the time required for the scanner of the imaging engine to expose the substrate. Some have approached this problem by increasing the speed at which the lasers are modulated, enabling the drum to be rotated at a higher rate. There are limitations, however, in the power of the laser and its speed of modulation. The plate emulsion also imposes limitations of total required exposure, energy or heat. Other solutions use spatial light modulators or laser arrays, so that multiple lines of the image can be exposed in each rotation of the drum. 
         [0007]    An alternative path to decreasing cycle time involves loading multiple substrates simultaneously on the drum. In one example, a number of substrates are positioned along the drum&#39;s axis. In still another approach, multiple substrates are loaded around the circumference of the drum. This, however, tends to have a limited impact on cycle time. The exposure step is consequently longer, since more substrate surface area must now be exposed. 
         [0008]    These approaches, however, address only one of the three throughput factors described above. In U.S. Pat. No. 6,722,280 (Shih et al.) a system is described for loading and unloading plates to and from an imaging drum simultaneously. However, for very large plates this arrangement is problematical and arrangements are preferred in which both the load and unload tables are horizontal, since a horizontal configuration is preferred for transport of large plates. 
         [0009]    While considerable effort has gone into devising auto-loading and auto-unloading systems for printing plates, the time taken to load and/or unload an individual plate remains problematical and is still a fundamental limitation to throughput in platesetters in the computer-to-plate environment. 
       SUMMARY OF THE INVENTION 
       [0010]    Briefly, according to one aspect of the present invention, a method for unloading a printing plate from a cylindrical surface of an imaging drum onto an unload table is shown, wherein the unload table comprises an unload table proximal segment. The method comprising positioning a first end of the printing plate proximate the unload table proximal segment by rotating the imaging drum about a cylindrical axis; orienting the unload table proximal segment close to and substantially tangential to the cylindrical surface by rotating the segment about a first axis in a first direction; and moving the printing plate onto the unload table proximal segment by rotating the imaging drum about a cylindrical axis. 
         [0011]    In some embodiments of the invention the method further comprises tilting of the unload table proximal segment to a clearance orientation and tilting the unload table itself to an unloading orientation about a second axis. These tilting actions may be performed in sequence or simultaneously. 
         [0012]    In a further aspect the invention, a method for unloading a printing plate from a cylindrical surface of an imaging drum onto an unload table is described. The unload table comprises an unload table proximal segment. The method comprising tilting of the unload table to an unloading orientation while imaging the printing plate. Yet another embodiment comprises tilting the unload table proximal segment to a clearance orientation before or during the tilting of the unload table to an unloading orientation. This embodiment can further comprise positioning a first end of the printing plate proximate the unload table proximal segment by rotating the imaging drum about a cylindrical axis; orienting the unload table proximal segment close to and substantially tangential to the cylindrical surface by rotating the unload table proximal segment about a first axis in a first direction; and moving the printing plate onto the unload table proximal segment by rotating the imaging drum about a cylindrical axis. 
         [0013]    In a further aspect the invention constitutes an unload table for unloading a printing plate from an imaging drum, the imaging drum having a cylindrical surface and the unload table comprising an unload table proximal segment proximate the cylindrical surface, the unload table proximal segment configured to be oriented close to and substantially tangential to the cylindrical surface by being swiveled with respect to the unload table about a first axis. The unload table is configured to be tilted to an unloading orientation about a second axis and the unload table proximal segment is capable of being placed in a clearance orientation. The unload table can be configured to be tilted to an unloading orientation about a second axis and the unload table proximal segment can be configured to be tilted to a clearance orientation before the unload table is tilted to an unloading orientation. In another embodiment of the present invention the unload table proximal segment is configured to be tilted to a clearance orientation while the unload table is being tilted to an unloading orientation. 
         [0014]    In yet a further aspect the invention constitutes an unload table for unloading a printing plate from an imaging drum, the unload table comprising an unload table proximal segment, the unload table capable of being placed in an unloading orientation while the printing plate is being imaged. The unload table proximal segment can be configured to tilt to a clearance orientation before or during tilting of the unload table to an unloading orientation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    In the drawings which illustrate non-limiting embodiments of the invention: 
           [0016]      FIG. 1  a is a schematic diagram of a prior art external drum-type plate making machine served by an unload table shown in the horizontal position; 
           [0017]      FIG. 1   b  is a schematic diagram of a prior art external drum-type plate making machine served by an unload table shown in the tilted position; 
           [0018]      FIG. 2   a  shows an external drum-type plate making machine with its unload table in a non-unloading configuration; 
           [0019]      FIG. 2   b  shows an external drum-type plate making machine with its unload table in an unloading configuration; and 
           [0020]      FIG. 3  is a flow chart according to a method of the present invention; 
           [0021]      FIG. 4   a  shows the orientation of unload table and unload table proximal segment while printing plate is being imaged or loaded on imaging drum; 
           [0022]      FIG. 4   b  shows unload table and unload table proximal segment in an orientation in which unload table is rotated about unload table tilt axis in unload table rotation direction to position the proximal end of unload table in an orientation in which the proximal end of unload table is close to cylindrical surface; 
           [0023]      FIG. 4   c  shows unload table and unload table proximal segment in an orientation in which printing plate is being unloaded from cylindrical surface of imaging drum; and 
           [0024]      FIG. 5  is a flow chart of another embodiment of the method according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
         [0026]    In  FIG. 1  a an imaging drum  10  of a plate making machine has a cylindrical surface  20  and can be rotated about its cylindrical axis  30 . At least one printing plate  40  may be located on cylindrical surface  20  of imaging drum  10 . Unload table  50  of the plate making machine has a proximal end proximate cylindrical surface  20  of imaging drum  10 , and a distal end, distal from cylindrical surface  20  of imaging drum  10 . The clearance between the proximal end of unload table  50  and cylindrical surface  20  is of such magnitude as to allow any clamps (not shown) holding printing plate  40  to cylindrical surface  20  to move past the proximal end of unload table  50  when imaging drum  10  rotates about cylindrical axis  30 . Given that there needs to be a load table (not shown) to supply printing plates to imaging drum  10 , and that such a load table also has requirements of proximity to and clearance with respect to cylindrical surface  20 , unload table  50  is capable of being rotated in unload table rotation direction  60  about unload table tilt axis  70 .  FIG. 1  a describes the orientation of the unload table while printing plate  40  is being imaged or loaded on imaging drum  10 . In the present specification, the term “starting orientation” is used to describe this orientation of unload table  50 . 
         [0027]      FIG. 1   b  shows the prior art apparatus of FIG. I a when printing plate  40  is unloaded from imaging drum  10 . To facilitate the unloading, the plate clamps proximate to the proximal end of unload table  50  are opened to release a first end of printing plate  40 . As a result, the first end of printing plate  40  is raised off cylindrical surface  20  due to the elasticity of the plate. Unload table  50  is rotated about unload table tilt axis  70  in unload table rotation direction  60  to position the proximal end of unload table  50  in an orientation in which the proximal end of unload table  50  is close to and substantially tangential to cylindrical surface  20 . The term “unloading orientation” is used to describe this orientation of unload table  50 . When imaging drum  10  is subsequently rotated in direction  80  about cylindrical axis  30 , printing plate  40  moves onto unload table  50  in direction  90 . To complete the unloading process, the rotation of imaging drum  10  is maintained until a second end of printing plate  40  is proximate the proximal end of unload table, at which point the clamps holding the second end of printing plate  40  to cylindrical surface  20  are opened and the second end of printing plate  40  is released. A suitable transporting device (not shown) on unload table  50  then moves printing plate  40  further onto unload table  50 , and unload table  50  rotates back about unload table tilt axis  70  to a starting orientation. 
         [0028]      FIG. 2   a  shows a first embodiment of the apparatus and method of the present invention. An imaging drum  110  of a plate making machine has a cylindrical surface  120  and can be rotated about its cylindrical axis  130 . At least one printing plate  140  may be located on cylindrical surface  120  of imaging drum  110 . Unload table  150  of the plate making machine comprises an unload table proximal segment  194 . Unload table proximal segment  194  has a proximal end proximate cylindrical surface  120  of imaging drum  110 , and a distal end, distal from cylindrical surface  120  of imaging drum  110 . Unload table proximal segment  194  is configured to be rotated about unload table proximal segment tilt axis  192 . 
         [0029]      FIG. 2   a  shows the orientation of unload table proximal segment  194  while printing plate  40  is being imaged or loaded on imaging drum  110 . In the present specification, the term “starting orientation” is used to describe this orientation of unload table proximal segment  194 . In this starting orientation, the clearance between the proximal end of unload table proximal segment  194  and cylindrical surface  120  is of such magnitude as to allow any clamps (not shown) holding printing plate  140  to cylindrical surface  120  to move past the proximal end of unload table  150  when imaging drum  110  rotates about cylindrical axis  130 . Clearance is also required for any clamp actuator assemblies (not shown). Since large imaging plates can be very heavy and difficult to transport, a preferred orientation for unload table  150  is a horizontal orientation. The starting orientation for unload table proximal segment  194 , shown as horizontal in  FIG. 2a , can be any advantageous orientation that conforms to the clearance described above. However, it should be kept in mind that there may be a load table serving imaging drum  110  with printing plates and that such a load table also has requirements of clearance and proximity. Unload table proximal segment  194  therefore has to have a starting orientation that allows any load table present adequate clearance and proximity with respect to cylindrical surface  120 . 
         [0030]      FIG. 2   b  shows unload table proximal segment  194  in an orientation in which printing plate  140  is being unloaded from cylindrical surface  120  of imaging drum  110 . In the present specification the term “unloading orientation” is used to describe such an orientation. To facilitate this unloading, the plate clamps proximate to the proximal end of unload table proximal segment  194  are opened to release a first end of printing plate  140 . As a result, the first end of printing plate  140  is raised off cylindrical surface  120  due to the elasticity of the plate. Unload table proximal segment  194  is rotated about unload table proximal segment tilt axis  192  in unload table proximal segment rotation direction  160  to position the proximal end of unload table proximal segment  194  in an orientation in which the proximal end unload table proximal segment  194  is close to and substantially tangential to cylindrical surface  120 . When imaging drum  110  is subsequently rotated in an imaging drum rotation direction  180  about cylindrical axis  130 , printing plate  140  moves onto unload table proximal segment  194  in direction  190 , and from there onto unload table  150 , or onto a plate punching device (not shown). To complete the unloading process, the rotation of imaging drum  110  is maintained until a second end of printing plate  140  is proximate the proximal end of unload table proximal segment  194 , at which point the clamps holding the second end of printing plate  140  to cylindrical surface  120  are opened and the second end of printing plate  140  is released. A suitable transporting device (not shown) on unload table  150  then moves printing plate  140  further onto unload table  150 , or onto the plate punching device, and unload table proximal segment  194  rotates back about unload table tilt axis  192  to the starting orientation. 
         [0031]    When unload table proximal segment  194  is in the unload orientation, the proximity of the proximal end of unload table proximal segment  194  to cylindrical surface  120 , as well as the angular deviation of unload table proximal segment  194  from the tangent to surface  120  near the proximal end of unload table proximal segment  194  are both chosen such that printing plate  140  is raised above the surface of unload table proximal segment  194  when printing plate  140  is released as described here. 
         [0032]    The method of use of this first embodiment of the present invention is described at the hand of  FIG. 3  with reference to  FIG. 2   a  and  FIG. 2b . The method for unloading printing plate  140  from cylindrical surface  120  of imaging drum  110  comprises:
       a) positioning ( 201 ) a first end of printing plate  140  proximate unload table proximal segment  194 ;   b) releasing ( 202 ) the clamps holding the first end of printing plate ( 140 ) to cylindrical surface  120 , the first end of printing plate  140  thereby lifting off cylindrical surface  120  due to its own elasticity;   c) rotating ( 203 ) unload table proximal segment  194  around about unload table proximal segment tilt axis  192  in unload table proximal segment rotation direction  160  to position unload table proximal segment  194  in an orientation in which it is close to and substantially tangential to cylindrical surface  120 ;   d) rotating ( 204 ) imaging drum  110  about cylindrical axis  130  to move printing plate  140  onto unload table proximal segment  194  in direction  190  and from there onto unload table  150 ;   e) moving ( 205 ) printing plate  140  further onto unload table  150  using a suitable transporting device (not shown); and   f) rotating ( 206 ) unload table proximal segment  194  to the starting orientation about unload table tilt axis  192 .       
 
         [0039]    Further operations involving the rotating of imaging drum  110  may be imitated as soon as enough clearance has been established between the proximal end of unload table proximal segment  194  and cylindrical surface  120  of imaging drum  110 . 
         [0040]    The benefit of this first embodiment of the present invention is that the unload table proximal segment  294  weighs much less than the entire unload table  250 . As a result it may be rotated faster, thereby improving throughput as compared with a solution involving the tilting of the entire unload table  50  as per the prior art. 
         [0041]      FIG. 4   a  shows a second embodiment of the apparatus and method of the present invention. An imaging drum  210  of a plate making machine has a cylindrical surface  220  and can be rotated about its cylindrical axis  230 . At least one printing plate  240  may be located on cylindrical surface  220  of imaging drum  210 . Unload table  250  of the plate making machine comprises an unload table proximal segment  294 . Unload table proximal segment  294  has a proximal end proximate cylindrical surface  220  of imaging drum  210 , and a distal end, distal from cylindrical surface  220  of imaging drum  210 . Unload table  250  is configured to be rotated about unload table tilt axis  260  and unload table proximal segment  294  is configured to be rotated about unload table proximal segment tilt axis  292 . 
         [0042]      FIG. 4   a  shows the orientation of unload table  250  and unload table proximal segment  294  while printing plate  240  is being imaged or loaded on imaging drum  210 . In the present specification, the term “starting orientation” is used to describe this orientation of unload table  250  and unload table proximal segment  294 . In this starting orientation, the clearance between the proximal end of unload table proximal segment  294  and cylindrical surface  220  is of such magnitude as to allow any clamps (not shown) holding printing plate  240  to cylindrical surface  220  to move past the proximal end of unload table  250  when imaging drum  210  rotates about cylindrical axis  230 . Clearance is also required for any clamp actuator assemblies (not shown). Since large imaging plates can be very heavy and difficult to transport, a preferred orientation for unload table  250  is a horizontal orientation. The starting orientation for unload table proximal segment  294 , shown as horizontal in  FIG. 2   a , can be any advantageous orientation that conforms to the clearance described above. However, it should be kept in mind that there may be a load table serving imaging drum  210  with printing plates and that such a load table also has requirements of clearance and proximity. Unload table proximal segment  294  therefore has to have a starting orientation that allows any load table present adequate clearance and proximity with respect to cylindrical surface  220 . 
         [0043]      FIG. 4   b  shows unload table  250  and unload table proximal segment  294  in an orientation in which unload table  250  is rotated about unload table tilt axis  270  in unload table rotation direction  260  to position the proximal end of unload table  250  in an orientation in which the proximal end of unload table  250  is close to cylindrical surface  220 . In  FIG. 4   b  unload table  250  is shown as positioned substantially tangential to cylindrical surface  220 . This is but one specific choice, and, in general, any other orientation advantageous to the unloading of printing plates from imaging drum  210  may be selected, subject to the requirements on unload table proximal segment  294  described below. The term “unloading orientation” is used to describe this orientation of unload table  250 . Before or while unload table  250  is rotated into its unloading orientation, unload table proximal segment  294  is rotated about unload table proximal segment tilt axis  292  in a first unload table proximal segment rotation direction  296 . The rotation of unload table  250  and unload table proximal segment  294  may be mutually independently controlled by a suitable controller, or may be linked such that, when unload table  250  is rotated in unload table rotation direction  260 , unload table proximal segment  294  is automatically rotated about unload table proximal segment tilt axis  292  in first unload table proximal segment rotation direction  296 . By rotating unload table proximal segment  294  in this fashion, adequate clearance is left between unload table proximal segment  294  and cylindrical surface  220  to allow any plate clamps present on cylindrical surface  220  to safely rotate past unload table proximal segment  294  if imaging drum  210  is rotated. This allows other processes involving the rotation of imaging drum  210  to continue while unload table  250  and unload table proximal segment  294  are being rotated as described in  FIG. 4   b . This enhances the throughput of the system, as the very heavy unload table  250 , which is slow to rotate, is being pre-positioned for the unload process even as, for example, imaging of printing plate  240  is proceeding on imaging drum  210 . By this approach unload table  250  finishes delivering a previously imaged plate to a further processing device and then immediately, or soon after, is tilted into it unload position in readiness for unloading the next imaged printing plate. Only unload table proximal segment  294 , which is much less heavy and capable of being rotated much faster, is kept clear of rotating imaging drum  210 . In the present specification the term “clearance orientation” is used to describe such an orientation of unload table proximal segment  294 . 
         [0044]      FIG. 4   c  shows unload table  250  and unload table proximal segment  294  in an orientation in which printing plate  240  is being unloaded from cylindrical surface  220  of imaging drum  210 . In the present specification the term “unloading orientation” is used to describe such an orientation of unload table proximal segment  294 . To facilitate this unloading, the plate clamps proximate to the proximal end of unload table proximal segment  294  are opened to release a first end of printing plate  240 . As a result, the first end of printing plate  240  is raised off cylindrical surface  220  due to the elasticity of the plate. Unload table proximal segment  294  is rotated about unload table proximal segment tilt axis  292  in second unload table proximal segment rotation direction  298  to position the proximal end of unload table proximal segment  294  in an orientation in which it is close to and substantially tangential to cylindrical surface  220 . In  FIG. 4   c  unload table proximal segment  294  is shown as being in straight line alignment with unload table  250 . This, as explained above in association with  FIG. 4   b , is but a particular choice. In general, any other orientation advantageous to the unloading of printing plates from imaging drum  210  may be selected for unload table  250 , subject to unload table proximal segment  294  being substantially tangential and close to cylindrical surface  220 . When imaging drum  210  is subsequently rotated in an imaging drum rotation direction  280  about cylindrical axis  230 , printing plate  240  moves onto unload table proximal segment  294  in direction  290 , and from there onto unload table  250 , or onto a plate punching device ( not shown). To complete the unloading process, the rotation of imaging drum  210  is maintained until a second end of printing plate  240  is proximate the proximal end of unload table proximal segment  294 , at which point the clamps holding the second end of printing plate  240  to cylindrical surface  220  are opened and the second end of printing plate  240  is released. A suitable transporting device (not shown) on unload table  250  then moves printing plate  240  further onto unload table  250 , or onto the plate punching device, and unload table proximal segment  294  and unload table  250  rotate back about unload table tilt axis  292  and unload table rotation axis  270  respectively to the starting orientation. 
         [0045]    When unload table proximal segment  294  is in the unload orientation, the proximity of the proximal end of unload table proximal segment  294  to cylindrical surface  220 , as well as the angular deviation of unload table proximal segment  294  from the tangent to surface  220  near the proximal end of unload table proximal segment  294  are both chosen such that printing plate  240  is raised above the surface of unload table proximal segment  294  when printing plate  240  is released as described here. 
         [0046]    The method of use of this second embodiment of the present invention is described at the hand of  FIG. 5  with reference to  FIG. 4   a ,  FIG. 4   b  and  FIG. 4   c . The method for unloading printing plate  240  from cylindrical surface  220  of imaging drum  210  comprises:
       a) positioning ( 310 ) unload table in an unloading orientation by rotating unload table  250  about unload table tilting axis  270  in unload tilting direction  260 ;   b) positioning ( 320 ) unload table proximal segment  294 , before or during positioning ( 310 ) of the unload table, in a clearance orientation;   c) positioning ( 330 ) a first end of printing plate  240  proximate unload table proximal segment  294 ;   d) releasing ( 340 ) the clamps holding the first end of printing plate ( 240 ) to cylindrical surface  220 , the first end of printing plate  240  thereby lifting off cylindrical surface  220  due to its own elasticity;   e) rotating ( 350 ) unload table proximal segment  294  around about unload table proximal segment tilt axis  292  in unload table proximal segment rotation direction  260  to position the proximal end of unload table proximal segment  294  in an orientation in which it is close to and substantially tangential to cylindrical surface  220 ;   f) rotating ( 360 ) imaging drum  210  about cylindrical axis  230  to move printing plate  240  onto unload table proximal segment  294  in direction  290  and from there onto unload table  250     g) moving ( 370 ) printing plate  240  further onto unload table  250  using a suitable transporting device (not shown) and   h) rotating ( 380 ) unload table proximal segment  294  to its starting orientation about unload table proximal segment tilt axis  292  and unload table  250  to its starting orientation about unload table tilt axis  270 .       
 
         [0055]    Further operations involving the rotating of imaging drum  210  may be initiated as soon as enough clearance has been established between the proximal end of unload table proximal segment  294  and cylindrical surface  220  of imaging drum  210 . 
         [0056]    The benefit of this second embodiment of the present invention is that the unload table proximal segment  294  weighs much less than the entire unload table  250 . As a result it may be rotated faster, thereby improving throughput as compared with a solution involving the tilting of the entire unload table  50  as per the prior art. It also allows the much heavier and thereby slow-moving unload table  250  to be re-oriented while the imaging drum  210  is engaged in processes other than unloading, thereby improving throughput. 
         [0057]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention. 
       PARTS LIST 
       [0000]    
       
           10  imaging drum 
           20  cylindrical surface 
           30  cylindrical axis 
           40  printing plate 
           50  unload table 
           60  unload table rotation direction 
           70  unload table tilt axis 
           80  imaging drum rotation direction 
           90  printing plate unload direction 
           110  imaging drum 
           120  cylindrical surface 
           130  cylindrical axis 
           140  printing plate 
           150  unload table 
           160  unload table proximal segment rotation direction 
           180  imaging drum rotation direction 
           190  printing plate unload direction 
           192  unload table proximal segment tilt axis 
           194  unload table proximal segment 
           201  positioning first end of printing plate 
           202  releasing clamps 
           203  rotating unload table proximal segment 
           204  rotating imaging drum 
           205  moving printing plate 
           206  rotating unload table proximal segment 
           210  imaging drum 
           220  cylindrical surface 
           230  cylindrical axis 
           240  printing plate 
           250  unload table 
           260  unload table rotation direction 
           270  unload table tilt axis 
           280  imaging drum rotation direction 
           290  printing plate unload direction 
           292  unload table proximal segment tilt axis 
           294  unload table proximal segment 
           296  first unload table proximal segment rotation direction 
           298  second unload table proximal segment rotation direction 
           310  positioning unload table 
           320  positioning unload table proximal segment 
           330  rotating unload table proximal segment 
           340  releasing clamps 
           350  rotating unload table proximal segment 
           360  rotating imaging drum 
           370  moving printing plate 
           380  rotating unload table proximal segment