Abstract:
A silicone application system for a web printing press includes at least one silicone applicator having a first web width application zone and a second web width application zone controlled independently of the first web with application zone. A web printing press and method are also disclosed.

Description:
[0001]    The present invention relates generally to printing presses and more particularly to an applicator formed to receive a liquid thereon and for at least to partly transfer the liquid onto a printed moving web or ribbon. 
       BACKGROUND 
       [0002]    In a rotary printing press, a material web is guided through a plurality of printing units where the web may be printed on both sides and in many colors. It is then guided into a dryer, for example, a hot air dryer, in order to dry it. The web is then transported over cooling rollers of a cooling stand in order to cool down the web heated by the dryer. Thereafter, the web may be cut and folded into signatures in a folder and the signatures transported onward for further processing in, for example, a distribution system. 
         [0003]    Presently, it is known to apply silicone to a full web or a full ribbon. U.S. Pat. No. 6,936,105 discloses a roller applicator for applying a liquid solution to a web. The silicone is transferred by a rotating applicator that resides in a reservoir of silicone emulsion. Coating the printed web with a silicone emulsion in the form of a thin film prevents the ink on the printed web from being smeared when in the region of turner bars or in the folder. 
         [0004]    U.S. Pat. No. 6,936,105 is hereby incorporated by reference herein. 
       SUMMARY OF THE INVENTION 
       [0005]    U.S. Pat. No. 6,936,105 limits the possibility for silicone to be applied to a specific area or areas of a full web. The silicone is limited to being applied to the full width of the web or not being applied at all. Thus, there can be excess or insufficient silicone in zones over the full web width. 
         [0006]    Furthermore, if there is a current requirement for multiple ribbons to be coated with silicone in a given process, multiple applicator rolls and all the components, such as reservoirs, motors and bearings, must be provided for each web and ribbon, which is costly. 
         [0007]    The present invention provides a silicone application system for a web printing press comprising: a silicone applicator having a first web width application zone and a second web width application zone controlled independently of the first web with application zone. 
         [0008]    The silicone application system may include a controller controlling the silicone applicator to permit selective application of the silicon in the first web width application and second web width application zones. 
         [0009]    The present invention also provides a web printing press comprising at least one print unit and the silicone application system of the present invention. 
         [0010]    The present invention also provides a method for providing silicone to a web comprising: 
         [0011]    determining a desired web width application zone; and 
         [0012]    controlling an application width of a silicone applicator as a function of the determination. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Further features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  shows a printing press according to the present invention; 
           [0015]      FIG. 2  shows a top view of  FIG. 1 ; 
           [0016]      FIG. 3  shows another embodiment of the present invention; 
           [0017]      FIG. 4  shows a top view of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]      FIG. 1  shows a web rotary printing press  10  including at least one printing unit  10  printing a web  5 . Web  5  is dried by a hot air dryer  20  and passes to a downstream cooling stand  30 . 
         [0019]    Since the ink may not fully set after exiting the dryer  20 , a printing ink buildup on the guide rolls or guide surfaces in the cooling stand  30  and subsequent press components, such as in the folding machine, may occur nevertheless. This ink buildup may be countered by applying a silicone emulsion onto web  5  using a silicon application system  40 . 
         [0020]    Silicone application system  40  used to apply a silicone emulsion onto web  5  may be located before or after cooling stand  30 . Due to the relatively small size of the silicone application system  40 , system  40  also may be located within the cooling stand  30 . 
         [0021]    As shown in  FIGS. 1 and 2 , silicone application system  40  includes a motor driven chrome roll  46  driven by motor M and a rubber roll  48 , which can press against chrome roll  46  using, for example, a hydraulic, pneumatic or another linear motion actuating device. Application system  40  also includes a series of spray nozzles  44  connected to a reservoir  42  containing a silicone solution. Spray nozzles  44  spray the solution onto the nip point between roll  46  and roll  48 , so that roll  48  thereafter applies silicone onto the underside of the full web  5 . Advantageously, silicone may also be similarly applied to the top of the full web  5  using a similar arrangement. Spray nozzles  44  may be controlled, for example, by solenoid valves which would allow for remote and pre-set operation using a controller  100 . This then allows controller  100  to apply the silicone solution at a desired flow rate and to any desired area or zone of web  5 , for example via automatic control or an operator. 
         [0022]    Furthermore, having multiple spray nozzles  44  means that nozzles  44  may be adjusted to spray silicon on one or more ribbons of any width. The quantity of nozzles  44  actually providing the silicone may vary depending on the desired location of the spray, the web width, by ribbon quantity or by ribbon width. Web width sensors  120 ,  126  may be used to determine a web width or location so that controller  100  can control the silicone applicator nozzles  44  automatically as a function of the web width or location. 
         [0023]    By having selective application, the amount and placement of silicone can be controlled, reducing the amount of silicone needed to be applied, and permitting selective zoning of silicone of desired. For example, of gumming or other issues downstream on specific axial areas is detected, additional silicone could be applied to that axial location to attempt to reduce the gumming. 
         [0024]    In another embodiment,  FIGS. 3 and 4  illustrate a silicone application system  50  using blades  49  made of, for example, plastic, metal or rubber to scrape off or restrict the flow of a silicone emulsion coming from reservoir  43  onto chrome roll  46 . Using multiple blades  49  (shown apart for clarity but capable of being spaced close together) allows application of the silicone solution to be controlled to any axial area or zone of web  5 . 
         [0025]    Blades  49  may be moved away and toward the roll  46  by, for example, individual rotary actuators, a mechanism or by hand. The number of blades  49  may be limited only by the desired location on the web, web width, number of ribbons or ribbon width. A web width sensor  120 ,  126  may be used to determine a web width so that controller  100  can control the silicone applicator blades  49  automatically as a function of the web width. 
         [0026]    The foregoing merely illustrates the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise numerous other arrangements which embody the principles of the invention and are thus within its spirit and scope. For example, based on the above disclosure, it is apparent that the principles of the invention can readily accommodate different control schemes other than a solenoid valve for remote operation and still achieve the benefits of the invention. Another example is that blades  49  and nozzles  44  can be pre-set or operated by hand.