Web conveying apparatus with brake

Abstract

A conveying apparatus includes: a conveyor including a brake to apply brakes to a web, the conveyor configured to convey the web while giving tension to the web by applying brakes to the web using torque of the brake; and a controller configured to control the conveyor. The controller performs at least one of a first control or a second control. The first control includes determining a first torque of the brake during acceleration of the web to be a value depending on a first inertial load at the conveyor during the acceleration of the web. The second control includes determining a second torque of the brake during deceleration of the web to be a value depending on a second inertial load at the conveyor during the deceleration of the web.

What is claimed is: 
     
         1 . A conveying apparatus comprising:
 a conveyor including a brake to apply brakes to a web, the conveyor configured to convey the web while giving tension to the web by applying brakes to the web using torque of the brake; and   a controller configured to control the conveyor,   wherein the controller is configured to perform at least one of a first control or a second control, the first control including determining a first torque of the brake during acceleration of the web to be a value depending on a first inertial load at the conveyor during the acceleration of the web, the second control including determining a second torque of the brake during deceleration of the web to be a value depending on a second inertial load at the conveyor during the deceleration of the web.   
     
     
         2 . The conveying apparatus according to  claim 1 , wherein upon changing the torque of the brake to the first torque or the second torque and upon changing the torque of the brake from the first torque or the second torque to another torque, the controller is configured to gradually change the torque of the brake. 
     
     
         3 . The conveying apparatus according to  claim 1 , wherein
 the conveyor includes a brake roller configured to be rotated by the web unwound from a web roll, and   the brake is configured to apply brakes to the web via the brake roller.   
     
     
         4 . The conveying apparatus according to  claim 1 , wherein the controller is configured to determine the first torque to be a value obtained by subtracting the first inertial load from a third torque of the brake during constant-speed conveyance of the web. 
     
     
         5 . The conveying apparatus according to  claim 1 , wherein the controller is configured to determine the second torque to be a value obtained by adding the second inertial load to a third torque of the brake during constant-speed conveyance of the web. 
     
     
         6 . The conveying apparatus according to  claim 3 , wherein the first inertial load is a product of a total of moments of inertia of all rollers for conveying the web including the brake roller in a section where the tension is generated in the conveyor and an angular acceleration of the brake roller during the acceleration of the web. 
     
     
         7 . The conveying apparatus according to  claim 3 , wherein the second inertial load is a product of a total of moments of inertia of all rollers for conveying the web including the brake roller in a section where the tension is generated in the conveyor and an angular acceleration of the brake roller during the deceleration of the web.