Abstract:
An inking system of a printing press includes an impression cylinder for guiding a printing substrate, and at least one ink-transfer roller. The ink-transfer roller includes a cylinder mandrel, on which at least one cylinder sleeve is concentrically displaceable, and bearing blocks, in which ends of the ink-transfer roller are mounted and which are independently displaceable in the radial direction of the impression cylinder. The ink-transfer roller can be set against the impression cylinder or any other ink-transfer roller, with a bearing block being detachable from one end of the ink-transfer roller and displaceable relative to the ink-transfer roller so that the cylinder sleeve can be removed via this one end. 
     A stop device, with which the cylinder sleeve can be brought into contact, has components that are movable in the axial direction of the print roller. The movable stop device components can be decelerated via a force-providing element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application of U.S. application Ser. No. 12/737,401, filed Mar. 11, 2011, now U.S. Pat. No. 9,156,244, the disclosure of which is incorporated by reference as is fully set forth herein. The aforementioned U.S. application Ser. No. 12/737,401 is a nationalization of PCT/EP09/04933, filed Jul. 8, 2009. 
     
    
     BACKGROUND ON THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The invention relates to an inking system of a printing press having an impression cylinder for guiding a printint substrate, at least one ink-transfer roller comprising a cylinder mandrel, on which at least one cylinder sleeve is concentrically displaceable, and bearing blocks, in which ends of the ink-transfer roller are mounted and which are displaceable independently of each other relative to the impression cylinder so that the ink-transfer roller can be set against the impression cylinder or any other ink-transfer roller, with a bearing block being detachable from one end of the ink-transfer roller and displaceable relative to the ink-transfer roller so that the at least one cylinder sleeve can be removed by way of the aforementioned one end. The invention also relates to a method of sliding a cylinder sleeve onto an ink-transfer roller that employs the elements of the above-described system. 
         [0004]    2. Description of the Prior Art 
         [0005]    It is frequently necessary to change ink-transfer rollers of one or more inking systems for carrying out print jobs. The document DE 102 20 608 C1 describes this process in detail, for example. The process in question relates primarily to print rollers that carry the print motif while other ink-transfer rollers, for example, anilox rollers, can frequently remain in the printing press. An inking system serves to print a motif by the use of a single ink. In different printing presses, an impression cylinder guiding the printing substrate can be assigned to each inking system. In other printing presses, it is possible to arrange a plurality of inking systems around a single impression cylinder. In this case, the printing substrate that is then usually present in the form of a web need not leave the impression cylinder, which is of advantage when printing plastic webs, for example. Such printing presses are often referred to as central cylinder printing presses and are primarily used in the field of package printing. The preferred printing process for this purpose is flexographic printing. 
         [0006]    In order to simplify and thus accelerate the process of setting up the printing press for the next job, the ink-transfer rollers are often provided with a multipart construction. A first part is the cylinder mandrel that remains in the printing press. One or more cylinder sleeves can now be slid onto this cylinder mandrel, the outer sleeve carrying a functional element. That is to say, the printing-cylinder sleeve carries the printing plate. All the inner sleeves serve only for adapting the diameter of the roller and thus the printing length and are therefore referred to as adapter sleeves. The inner sleeves are often limited to one sleeve at most for reasons of stability. 
         [0007]    For changing the cylinder sleeves, the cylinder mandrel that is otherwise mounted at both ends thereof in bearing blocks that are displaceable relative to the frame of the printing press or the impression cylinder is exposed at one end thereof. For this purpose, the cylinder mandrel is detached from the bearing block in question. This bearing block is then displaced relative to the cylinder mandrel so that one or more sleeves can now be pulled off by way of this free end in the axial direction of the ink-transfer roller and new sleeves can be slid onto the same. 
         [0008]    For defining the axial position of a sleeve on the cylinder mandrel, the latter often comprises a stationary ring, against which the cylinder sleeve is slid. In doing so, the cylinder sleeve often violently strikes against the ring so that this results in damage to cylinder sleeves or cylinder mandrels in the long term, more particularly when the cylinder sleeves are adapter sleeves that are heavy, in part. 
       SUMMARY OF THE INVENTION 
       [0009]    It is therefore an object of the present invention to suggest an inking system, in which damage of such type is prevented. This object is achieved with an inking system having a stop device, with which the cylinder sleeve can be brought into contact, with components of the stop device being movable in the axial direction of the print roller, and the components of the stop device being decelerated in their movement via force-providing element. 
         [0010]    Accordingly, a stop device is provided, with which the cylinder sleeve can be brought into contact, components of the stop device being movable in the axial direction of the print roller. Furthermore, provision is made according to the invention for decelerating the components of the stop device during their movement by means of a force-providing element. 
         [0011]    The invention thus performs the following function: When a cylinder sleeve is slid onto the cylinder mandrel, the former strikes against components of the stop device before striking against the stationary ring of the cylinder mandrel. Since the components of the stop device are movable in the axial direction, they are set in motion by the cylinder sleeve. But this movement can be decelerated by means of the force-providing element. It is thus possible to decelerate the movement of the cylinder sleeve, in particular so that it strikes against the stationary ring at the lowest speed possible. Damage to the cylinder sleeve and/or cylinder mandrel is prevented in this way. 
         [0012]    In an advantageous embodiment, the force-providing element comprises a spring element that is preferably supported against the bearing block and/or the frame of the printing press. The spring force for this purpose should be selected such that it does not increase to an excessive level when the cylinder sleeve strikes against the stationary ring since otherwise the cylinder sleeve is again accelerated in the opposite direction. 
         [0013]    In a further embodiment, provision is made for the force-providing element to comprise a pressurizing-medium cylinder comprising at least one pressure chamber that can be subjected to positive or negative pressure. It is preferred to provide positive pressure since compressed air is usually used in printing presses. However, a resilient effect can also be observed in this embodiment. This means that the force provided increases with the distance covered. 
         [0014]    In order to prevent the aforementioned effect, provision is preferably made to reduce the counteracting force supplied by the force-providing element during the movement. If a spring element is used, this means that the support of the spring element must be displaceable. 
         [0015]    In a preferred embodiment, however, the pressure chamber of the pressurizing-medium cylinder is provided with a supply and/or discharge line, by means of which a pressurizing medium, preferably compressed air, can be supplied or discharged. Furthermore, a throttle element is provided in this supply and/or discharge line, by means of which throttle element the flow velocity of the pressurizing medium can be reduced within parts of the supply and/or discharge line. In this embodiment, the pressurizing medium is thus not constantly compressed or relieved to an increasing degree so that there is no increasing force exerted. Rather, the pressurizing medium flows through the supply and/or discharge line out of the pressure chamber or into the same. In doing so, the pressurizing medium also flows through a throttle element so that the pressurizing medium indeed exists in a compressed or relieved state, but the pressure prevailing inside the pressure chamber, as far as possible, hardly changes. In this way, it is possible to decelerate the printing sleeve by the use of a constant force as far as possible. This results in a constant deceleration. It is advantageous if the throttle element comprises an adjusting device, by means of which the flow velocity can be controlled so that the stop device can be adapted in terms of its decelerating action to suit the weight of the sleeve used. 
         [0016]    Furthermore, it is very advantageous if the stop device can be set against the front side of the cylinder sleeve or removed therefrom by means of the pressurizing-medium cylinder so that the stop device does not remain in contact with said front side during the rotation of the ink-transfer roller. 
         [0017]    It is also advantageous if the stop device is equipped with a compressed-air supply line and a compressed-air outlet, the compressed-air outlet being connectable to a compressed-air supply opening of the cylinder sleeve. In this way, the stop device can be used to apply compressed air to a so-called adapter sleeve so that the sleeve surrounding this adapter sleeve can be pulled off easily by the use of a small force. If the stop device does not have this configuration, then a separate compressed-air supply device would have to be provided for the cylinder sleeve in the printing press described. It is thus possible by means of the embodiment of the invention described to cut down on installation space. 
         [0018]    An exemplary embodiment of the invention is revealed in the following description and the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    In the individual figures of the drawings: 
           [0020]      FIG. 1  is a side view of a portion of a printing press, 
           [0021]      FIG. 2  shows a view taken along line II-II marked in  FIG. 1 , 
           [0022]      FIG. 3  corresponds to  FIG. 2 , but includes the cylinder sleeve that is slid on the print roller, 
           [0023]      FIG. 4  corresponds to  FIG. 3 , but shows the stop device that is removed from the cylinder sleeve, 
           [0024]      FIG. 5  corresponds to  FIG. 4 , but shows the stop device that is again set against the cylinder sleeve. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
         [0026]      FIG. 1  is a side-view of an inking system  1  of a printing press. This inking system  1  comprises a print roller  2  and an anilox roller  3 . The print roller  2  can be set against the impression cylinder  4 , on which the printing substrate (not shown in the figure) travels. The anilox roller  3  can, in turn, be set against the print roller  2 . The two rollers  2  and  3  are mounted by means of their respective two ends in bearing blocks, of which only the front bearing blocks are shown. The bearing block  5  is thus assigned to the print roller  2 . The bearing block  6  is assigned to the anilox roller  3 . In order to move the rollers so as to set them against and remove them from each other, the bearing blocks  5  and  6  are displaceable along the rail  7  in the direction of the double arrow  8 . Similarly, the rear bearing blocks (not shown in the figure) are also displaceable along a rail. The displacement is carried out by means of suitable drive systems that are known per se and are not described here in detail. 
         [0027]    Both the print roller  2  and the anilox roller  3  are composed of a cylinder mandrel and one or more cylinder sleeves (not shown in detail in  FIG. 1 ). In order to be able to change the cylinder sleeves, the bearings that support the ends of the mandrels can be removed from the same. The bearing blocks  5  and  6  can then be moved aside. The cylinder mandrels are now held only by the rear bearing blocks. This unilateral bearing is also referred to as “cantilever support.” The sleeves can now be removed from the mandrels and replaced with new ones. 
         [0028]      FIG. 2  shows a view taken along line II-II marked in  FIG. 1 . The construction of the print roller  2  comprising a cylinder mandrel  9  and a cylinder sleeve  10  is evident from this figure. This figure shows the print roller  2  while the cylinder sleeve  10  is being slid onto the same. The cylinder sleeve  10  usually has an inside diameter that is slightly smaller than the outside diameter of the cylinder mandrel  9 . The inner surface of the cylinder sleeve, however, is made of a compressible material so that compressed air flowing from small openings of the cylinder mandrel  9  expands the inside diameter of the cylinder sleeve  10  to such an extent that it is possible to easily slide the cylinder sleeve  10  onto the print roller. In doing so, the cylinder sleeve  10  slides properly on an air cushion. The cylinder sleeve can now be slid onto the print roller in the direction of the arrow  11 . In other printing presses, it is possible to use cylinder sleeves  10 , of which the inside diameter is larger than the outside diameter of the cylinder mandrel. In this case, such a sleeve  10  can also be slid onto the print roller without the use of any air cushion. When the sleeve has reached the axial position intended, it can be locked into position, for example, by means of so-called tensile-stress elements. A tensile-stress element can be a section of the cylinder mandrel  9 , which section has an outside diameter that can be enlarged, for example, by a hydraulic force acting from within in order to thus lock the cylinder sleeve in position. The regions of the cylinder sleeve  10 , on which such tensile-stress elements act, should not be compressible. 
         [0029]    The cylinder mandrel  9  comprises, on one side thereof, a section that has an enlarged diameter and that can be in the form of a ring  12 . The ring  12  and the cylinder mandrel  9  can be connected to each other permanently or formed integrally. This ring  12  serves for defining the axial position of the cylinder sleeve  10 . In other words, the cylinder sleeve  10  is slid until it strikes against the ring. The cylinder sleeve  10  can, as shown in  FIG. 2 , comprise a section  13 , in which the inside diameter is enlarged. This section  13  can then encompass the ring. The front side  14  of the ring thus serves as a stop surface for the cylinder sleeve  10 . Since the air cushion described above enables the sleeve  10  to be slid smoothly onto the mandrel  9  in the axial direction shown by the arrow  11 , the sleeve  10  can be slid at a relatively high speed against the ring so that the possibility of damage cannot be ruled out. 
         [0030]    In order to reduce the possibility of damage, it is advantageous to decelerate the cylinder sleeve  10  before it impinges on the ring. For this purpose, a stop device  15  is provided according to the invention. The latter comprises a stop  16  attached to the piston rod  17  of a pressurizing-medium cylinder  18 . A reciprocating piston  19 , to which the piston rod  17  is attached, is disposed inside the pressurizing-medium cylinder  18 . In  FIG. 2 , the first chamber  20  that is delimited by that side of the reciprocating piston  19  that is oriented away from the piston rod  17  is filled with a pressurizing medium, preferably compressed air that is subjected to positive pressure. This causes the piston rod to extend so far that the cylinder sleeve  10  strikes against the stop before striking against the ring  12 . The first chamber  20  is connected to a first supply and discharge line  21 , by means of which the pressurizing medium can be supplied or discharged. A throttle  22  that ensures that the pressurizing medium flows only at a reduced velocity is installed in this supply and discharge line  21 . Advantageously, the flow resistance formed by the throttle  22  can be adjusted by means of an adjusting device represented by the arrow  32 . The open end  23  of the supply and discharge line  21  shown in  FIG. 2  opens into the atmosphere. 
         [0031]    When the cylinder sleeve  10  is now slid onto the cylinder mandrel  9 , the former strikes against the stop  16 , as a result of which the reciprocating piston is ultimately moved against the pressure prevailing in the first chamber  20  and the pressurizing medium is compressed further. Thus the kinetic energy of the cylinder sleeve  10  is absorbed and the latter is decelerated. In order to prevent the restoring force generated by the compressed pressurizing medium from increasing to an excessive level, the pressurizing medium can escape by way of the supply and discharge line  21  and the throttle  22 , while a positive pressure persists in the first chamber or reduces in a delayed manner. It is thus possible by means of the arrangement suggested by the invention to decelerate the cylinder sleeve  10  on its travel up to the ring and at the same time allow the pressurizing medium to escape so that ultimately, when the cylinder sleeve  10  bears against the ring, there is no more restoring force acting on the cylinder sleeve in a direction extending opposite to the one represented by the arrow  11 . 
         [0032]    This situation is shown in  FIG. 3 . It is further evident from  FIGS. 2 and 3  that the stop is provided with a compressed-air outlet  24 , in which a compressed-air supply line  25  ends. When the cylinder sleeve  10  bears against the stop  16 , this compressed-air outlet  24  engages in the compressed-air supply opening  26  so that compressed air can be applied to the cylinder sleeve  10 . An additional sleeve can now be slid onto the cylinder sleeve  10 , which can guide the compressed air by means of a compressed-air line system through openings on its outer circumference. This additional sleeve can in turn be slid easily onto the cylinder sleeve due to the resulting air cushion. 
         [0033]    For printing purposes, the stop  16  must now be removed from the cylinder sleeve  10 . For this purpose, a pressurizing medium that is subjected to positive pressure can easily be guided into the second chamber  28  by means of the second supply line  27  so that the reciprocating piston  19  and thus the stop  16  are again displaced in the direction of the arrow  11  until the compressed-air outlet is completely pulled out of the compressed-air supply opening  16  [sic:  26 ]. 
         [0034]    In  FIG. 3 , the first supply and discharge line does not open out into the ambience, but instead into a directional valve  30 . The latter is switched in such a way for the purpose of sliding the cylinder sleeve  10  that the pressurizing medium can escape into an unpressurized region. If compressed air is used, the same is easily released into the ambience. 
         [0035]    The directional valve can be switched, as shown in  FIG. 4 , for pulling off the cylinder sleeve  10 . In this way, the supply and discharge line  21  can be connected to a positive-pressure source. The reciprocating piston  19  and thus the stop  16  now exert a force in the direction of the arrow  28  [sic:  29 ]. It is thus possible to simplify even the process of pulling off the cylinder sleeve, if required, since the stop  16  acts as the means to push off the cylinder sleeve. 
         [0036]    The invention being thus described, it will be apparent that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be recognized by one skilled in the art are intended to be included within the scope of the following claims. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 Inking system 
               
               
                 2 
                 Print roller 
               
               
                 3 
                 Anilox roller 
               
               
                 4 
                 Impression cylinder 
               
               
                 5 
                 Bearing block 
               
               
                 6 
                 Bearing block 
               
               
                 7 
                 Rail 
               
               
                 8 
                 Double arrow 
               
               
                 9 
                 Cylinder mandrel 
               
               
                 10 
                 Cylinder sleeve 
               
               
                 11 
                 Arrow 
               
               
                 12 
                 Ring 
               
               
                 13 
                 Section having an enlarged inside diameter 
               
               
                 14 
                 Front side of the ring 
               
               
                 15 
                 Stop device 
               
               
                 16 
                 Stop 
               
               
                 17 
                 Piston rod 
               
               
                 18 
                 Pressurizing-medium cylinder 
               
               
                 19 
                 Reciprocating piston 
               
               
                 20 
                 First chamber 
               
               
                 21 
                 First supply and discharge line 
               
               
                 22 
                 Throttle 
               
               
                 23 
                 Open end 
               
               
                 24 
                 Compressed-air outlet 
               
               
                 25 
                 Compressed-air supply line 
               
               
                 26 
                 Compressed-air supply opening 
               
               
                 27 
                 Second supply line 
               
               
                 28 
                 Second chamber 
               
               
                 29 
                 Arrow 
               
               
                 30 
                 Directional valve 
               
               
                 31 
                 Frame of printing press 
               
               
                 32 
                 Arrow (Adjusting device)