Method and device for processing a paper or film web

Abstract

The invention relates to a method for processing a paper or film web ( 10 ). According to said method, the web ( 10 ) is first fed underneath a braking element ( 12 ), scanned by a reader ( 15 ) and subsequently conveyed at varying speeds by a conveyer drive ( 16 ). The braking element ( 12 ), e.g. a brush ( 30 ), exerts a varying braking force on the paper or film web ( 10 ), thus holding the web ( 10 ) taut and preventing undulations in said web between the braking element ( 12 ) and the conveyer drive ( 16 ). This improves the legibility of control marks for the reader ( 15 ), reduces the load on the conveyer drive ( 16 ) and prevents paper-feed malfunctions. The method can be advantageously used to feed a paper or film web ( 10 ) in a stop-and-go operation to a cutting device ( 22 ), which cuts the web ( 10 ) transversally to the direction of transport using a guillotine ( 24 ).

1 - 17 . (canceled)  
     
     
         18 . A method for processing a paper or film web ( 10 ), the web ( 10 ) first being fed underneath a braking element ( 12 ), then scanned by a reader ( 15 ) and finally conveyed at varying speeds by a conveyor drive ( 16 ), characterized in that the braking element ( 12 ) acts with a varying braking force on the paper or film web ( 10 ), so that the web is tautened and the formation of undulations of the web between braking element ( 12 ) and conveyor drive ( 16 ) is avoided.  
     
     
         19 . The method as claimed in  claim 18 , characterized in that the braking element ( 12 ) is pressed against the paper or film web ( 10 ) in a dragging manner with a varying contact pressure.  
     
     
         20 . The method as claimed in  claim 18 , characterized in that the paper or film web ( 10 ) is accelerated and braked periodically by the conveyor drive ( 16 ), a higher force being chosen during braking than during acceleration.  
     
     
         21 . The method as claimed in  claim 19 , characterized in that the braking element ( 12 ) acts on the web ( 10 ) with the higher braking force substantially after the start of braking the paper or film web ( 10 ) and at least as far as the stoppage of the web ( 10 ).  
     
     
         22 . The method as claimed in  claim 19 , characterized in that the braking element ( 12 ) has a movable brush ( 30 ).  
     
     
         23 . The method as claimed in  claim 18 , characterized in that transport speed of the web ( 10 ) and/or a tension of the web ( 10 ) is/are preferably measured and the braking force is set on the basis of the measured transport speed and/or tension.  
     
     
         24 . A device for processing a paper or film web ( 10 ), in particular as a feed to a cutting device ( 22 ), comprising a braking element ( 12 ), a conveyor drive ( 16 ) arranged after the braking element ( 12 ) for accelerating and retarding the web ( 10 ) and a reader ( 15 ) for scanning the web ( 10 ) between the braking element ( 12 ) and the conveyor drive ( 16 ), characterized in that the braking element ( 12 ) acts on the paper or film web ( 10 ) with a varying braking force, such that the web ( 10 ) is tautened and the formation of undulations of the web ( 10 ) between braking element ( 12 ) and conveyor drive ( 16 ) is avoided.  
     
     
         25 . The device as claimed in  claim 24 , characterized by means ( 33 ,  34 ) which press the braking element ( 12 ) against the paper or film web ( 10 ) in a dragging manner with a varying contact pressure.  
     
     
         26 . The device as claimed in  claim 24 , characterized by a controller ( 20 ,  27 ) which controls the conveyor drive ( 16 ) such that the paper or film web ( 10 ) is periodically accelerated and braked, and which controls the braking element ( 12 ) such that the braking force is chosen to be lower during acceleration than during braking.  
     
     
         27 . The device as claimed in  claim 26 , characterized in that the controller ( 20 ,  27 ) controls the braking element ( 12 ) such that it acts on the paper or film web ( 10 ) with the higher braking force substantially after the start of braking the paper or film web ( 10 ) and at least as far as a stoppage of the web ( 10 ).  
     
     
         28 . The device as claimed in  claim 25 , characterized in that the braking element ( 12 ) has a movable brush ( 30 ).  
     
     
         29 . The device as claimed in  claim 25 , characterized in that the braking element ( 12 ) comprises a rotary magnet ( 33 ,  34 ) having two, in particular adjustable, stops.  
     
     
         30 . The device as claimed in  claim 25 , characterized in that the braking element ( 12 ) comprises a motor ( 29 ).  
     
     
         31 . The device as claimed in  claim 26 , characterized in that it comprises a measuring device ( 26 ,  28 ) which measures a transport speed of the web ( 10 ) and/or a tension of the web ( 10 ), and in that the controller ( 20 ,  27 ) comprises means for setting the braking force on the basis of the transport speed and/or tension measured by the measuring device ( 26 ,  28 ).  
     
     
         32 . The device as claimed in  claim 26 , characterized by a cutting device ( 22 ), which cuts the paper or film web ( 10 ) transversely with respect to the transport direction by means of a guillotine ( 24 ) during a stoppage, the paper or film web ( 10 ) being fed to the cutting device ( 22 ) in stop and go operation.  
     
     
         33 . The device as claimed in  claim 32 , the reader ( 15 ) detecting control features and controlling the cutting device ( 22 ).  
     
     
         34 . A braking element for a device for processing a paper or film web ( 10 ), in particular as claimed in  claim 24 , characterized by means which press the braking element ( 12 ) against the paper or film web ( 10 ) in a dragging manner with a varying contact pressure.