Web tension adjustment device and web winding device

Abstract

A web tension adjustment device includes a pair of guide rollers and a dancer roller. The two guide rollers are spaced at least in a gravity direction and guide continuous paper in transfer. The dancer roller moves within a moving range along a guide shaft extending in a direction intersecting a rotation axis distance direction of the pair of guide rollers at an acute angle, rolls on the continuous paper transferred between the pair of guide rollers and gives tension to the continuous paper, the tension corresponding to an amount of moving from a position between the pair of guide rollers along the guide shaft.

What is claimed is: 
     
         1 . A web tension adjustment device, comprising:
 a pair of guide rollers spaced at least in a gravity direction and guiding a web in transfer; and   a dancer roller that moves within a moving range along a guide extending in a direction intersecting a rotation axis distance direction of the pair of guide rollers at an acute angle, rolls on the web transferred between the pair of guide rollers and gives tension to the web, the tension corresponding to an amount of moving along the guide from a position between the pair of guide rollers.   
     
     
         2 . The web tension adjustment device according to  claim 1 , wherein
 the dancer roller gives the tension to the web in a control range that is positioned lower than the pair of guide rollers in the gravity direction within the moving range and moves upward within the moving range to a work position between the pair of guide rollers in a work of hanging across the web.   
     
     
         3 . The web tension adjustment device according to  claim 1 , wherein
 the extending direction of the guide is a direction inclined at an angle of 20 degrees or greater to the rotation axis distance direction and at an angle of 30 degrees or less to the gravity direction.   
     
     
         4 . The web tension adjustment device according to  claim 1 , wherein
 the pair of guide rollers and the dancer roller are arranged on a transfer route of the web to be wound around a winding roll.   
     
     
         5 . The web tension adjustment device according to  claim 1 , wherein
 a rotation axis distance L of the pair of guide rollers satisfies a formula:
     L =( r 1+ r 2+ d 3+ a )/sin θ
 
   where “r1” is a radius of a guide roller on an upstream side, the guide roller on the upstream side being one, arranged upstream of the dancer roller in a transfer direction of the web, of the pair of guide rollers, “r2” is a radius of a guide roller on a downstream side, the guide roller on the downstream side being the other, arranged downstream of the dancer roller in the transfer direction of the web, of the pair of guide rollers, “d3” is a diameter of the dancer roller, “a” is a minimum clearance between a guide roller and the dancer roller, the guide roller being one of the guide roller on the upstream side and the guide roller on the downstream side arranged below in the gravity direction, and “θ” is an angle between the rotation axis distance direction and the extending direction of the guide.   
     
     
         6 . A web winding device, comprising:
 a winder that winds a web; and   a web tension adjustment device used for a tension adjustment mechanism that adjusts tension of the web to be wound by the winder,   wherein the web tension adjustment device includes:   a pair of guide rollers spaced at least in a gravity direction and guiding the web in transfer; and   a dancer roller that moves within a moving range along a guide extending in a direction intersecting a rotation axis distance direction of the pair of guide rollers at an acute angle, rolls on the web transferred between the pair of guide rollers and gives tension to the web, the tension corresponding to an amount of moving along the guide from a position between the pair of guide rollers.