Method for reducing register errors on a web of material moving through the printing nip of a multicolor web-fed rotary press and corresponding devices

A multi-color web-fed rotary printing press comprising:

• at least a first printing group and at least one second printing groups, each of said printing groups defining a printing gap and arranged to print at least first and second colors on a web passing through said at least first printing group and said at least one second printing group;
• at least one bendable roller positioned at an inlet to at least one of said at least first and second printing groups, said at least one bendable roller being looped by said web;
• at least one sensor adapted to detect a register error on said web and located after, in a running direction of said web, said first printing group;
• and
• at least one actuating member usable to set a curvature of said at least one bendable roller selectively in, and opposite to said running direction of said web and wherein said curvature of said at least one bendable roller is set in response to said register error detected by said at least one sensor in said at least first and second colors printed on said web, in said running direction of said web.