Width adjusting device and method for a paper web, and lithographic rotary press having same

A printing apparatus through which a dampened paper web travels, said printing apparatus comprising:

• first and second printing sections which each print an image on said dampened paper web as said dampened paper web travels through said first and second printing sections;
• means for variably changing a width of said dampened paper web so that said image formed on said dampened paper web at said first printing section and said image formed on said dampened paper web at said second printing section are properly aligned with each other, said changing means being disposed between said first and second printing sections;
• wherein said changing means includes first and second contact devices disposed at opposite first and second surfaces of said dampened paper web such that said dampened paper web travels between said first and second contact devices, said first and second contact devices respectively having a plurality of first and second contact members disposed thereon along an axial direction such that said plurality of first contact members of said first contact device are staggered relative to said plurality of second contact members of said second contact device thereby producing an alternating sequence of individual first and second contact members as viewed along said axial direction;
• further comprising a plurality of rotatable cylinders which drive said dampened paper web, said axis of rotation of each of said rotatable cylinders being approximately parallel to said axial direction;
• wherein said changing means includes means for moving said first plurality of contact members into and out of contact with said first surface and for moving said second plurality of contact members into and out of contact with said second surface, and when said first and second plurality of contact members are in contact with said dampened paper web, said width of said dampened paper web is reduced as compared to when said first and second plurality of contact members are not in contact with said dampened paper web;
• further comprising means for controlling said moving means such that said width of said dampened paper web can be variably changed in response to an extent of movement of said first and second plurality of contact members into contact with said dampened paper web;
• further comprising an input device through which information concerning the dampened paper web is provided to said controlling means, said information being used by said controlling means to determine said extent of movement;
• wherein said first and second plurality of contact members each are a roller member having a circumferential contact surface in elastic contact with said dampened paper web;
• wherein said first contact device includes a first shaft on which said first plurality of contact members are mounted, said second contact device includes a second shaft on which said second plurality of contact members are mounted and said changing means further includes first, second, third and fourth rotatable members each having a sleeve projecting from a surface thereof at an eccentric position relative to an axis of rotation of said rotatable member, first and second ends of said first shaft are respectively disposed in said sleeves of said first and second rotatable members and first and second ends of said second shaft are respectively disposed in said sleeves of said third and fourth rotatable members.