A method for operating webfed printing presses producing printed products, includes providing a reel stand and printing units. A flying web change from first to a second webs takes place with production of a splice, and settings are made on printing units coordinating with passage of the splice through the press. At least two printing units are configured as double printing units for flexographic printing and operated for producing printed products. Each double printing unit includes first and second partial printing units, and first or second partial printing units are activated or deactivated according to passage of the splice through the press, or a switchover occurs from first to second partial printing units of the double printing unit, or vice versa. The flexographic printing press is operable nonstop and automatically during web change. When operating a web-processing rotary printing press for flexographic printing, automation, productivity and print quality increases.

Described herein is a sheet supply apparatus for continuously supplying sheets while splicing the leading edge of the sheet of a standby roll to the trailing end of a sheet being unwound from a working roll by using an auto splicer, the sheet supply apparatus including: a turret unwinder provided with fixation chucks that each fix both ends of a paper tube, and configured to switch the positions of the standby and working rolls; a detector configured to detect the position of one of both axial ends of the standby roll; a corrector configured to be connected to each of the fixation chucks and to correct the position of the standby roll; and a controller configured to align an end of the standby roll so that the end of the standby roll is aligned with the end of the working roll while correcting the position of the standby roll.

An unwinder for unwinding reels of paper includes a supporting structure partially closed and defining an internal space suitable for unwinding at least one reel; the supporting structure includes: a first lateral support; a second lateral support spaced from the first support; a crosspiece interposed above between the first and the second support defining with the first support and second support the partially closed structure; the unwinder further includes: a first axial unwinding system placed at the first support and configured to axially unwind a first reel; a second axial unwinding system placed at the second support and configured to unwind a second reel; a joining device placed at the crosspiece and configured to make a joint between a first ply belonging to the first reel and a second ply belonging to the second reel to perform a reel exchange.