Method of and apparatus for winding web

Abstract

When an elongate film is initially wound around a core, it is wound under a low winding tension command value T 1 corresponding to the length of the core. Then, after the tension is progressively increased at a predetermined rate, the elongate film is wound while its tension is gradually lowered from a high winding tension command value T 3.

1 . A method of winding a web, comprising the steps of: 
 supporting the web on an outer circumferential surface of a core with a plurality of rollers, and rotating the core with a gap being defined by blocks between the blocks and the outer circumferential surface of the core for passage of the web therethrough;    retracting said rollers and said blocks from the core successively from regions where a leading end of the web has passed; and    after the web is wound around the core by at least one turn, retracting all the said rollers and said blocks from the core.    
     
     
         2 . A method according to  claim 1 , wherein a time to move said rollers and said blocks is determined based on an output signal from an encoder which is associated with a reference roller for feeding said web.  
     
     
         3 . An apparatus for winding a web around a core, comprising: 
 a core rotating mechanism for rotating the core; and    a winding mechanism for guiding the web around the core when the core is rotated;    said winding mechanism comprising: 
 a movable pressing roller for pressing the web against the core to support the web thereon and for being pressed against the core in a direction opposite to the direction in which the tension of at least the web is applied; and  
 a plurality of movable blocks for creating a gap for passage of the web between the movable blocks and an outer circumferential surface of the core.  
   
     
     
         4 . An apparatus according to  claim 3 , wherein said pressing roller includes first and second pressing rollers symmetrically positioned with respect to a hypothetical reference line which extends parallel to the direction indicated in which the tension of the webs is applied and also extends through centers of the cores, said first and second pressing rollers being rotatably mounted on one of said blocks.  
     
     
         5 . An apparatus according to  claim 4 , wherein said block on which said first and second pressing rollers are rotatably mounted is movable toward and away from the core by an actuator with a pressing force adjusting function.  
     
     
         6 . An apparatus according to  claim 4 , wherein said winding mechanism comprises: 
 a bearing roller for engaging the core in opposite relation to said first and second pressing rollers; and    a third pressing roller and a winding nip roller which are disposed on a hypothetical line which extends across said hypothetical reference line and also extends through centers of the core, and which are disposed in sandwiching relation to the core, said third pressing roller and said winding nip roller being movable toward and away from each other.    
     
     
         7 . An apparatus according to  claim 3 , wherein said winding mechanism comprises a plurality of winding mechanisms arrayed axially of the core, with only a predetermined number of winding mechanisms, depending on the axial length of the core, among said plurality of winding mechanisms being disposed in a position to wind the web.