Let's place it at the start of a printing press.
The mettabook (or, more precisely, "mettafoglio") is a special automatic offset printing machine that allows the fast and consecutive entry of the various paper sheets inside them.
This is a complex and precision mechanism, located in front of the printing machines, which normally uses suction cups to lift and "take" the single sheet of paper; Thus, each sheet is moved in rapid succession to a plane provided with conveyor belts where it is "hooked" by the swinging pliers and transported to the printing unit where the printing process begins.
More generally, the term "mettafoglio" is used to indicate similar mechanisms for the introduction of sheet materials (other than paper) for other industrial processes (ligature, perforation, bending, plastification, etc.). Thus, for example, with the advent and diffusion of digital copiers and digital prints, then in these areas, the bullet point indicates the device (generally already integrated within the different machines) of paper input. Wikitesto modem control devices
Thickness Meter: Check if more than one sheet is passed. Front register: It is used to straighten the sheet into the print group. Side register (squares): Adjust the paper size and check that the media does not move sideways. Pneumatic Front Log Control: A series of holes located close to the front register are connected to a compressed air device; if the sheet closes the holes out of the air then it means the sheet has stopped correctly against the front register. If the sheet does not close the holes causing air leakage, the device sounds an alarm. Optical Side Log Control: A series of light sources and optical sensors are placed along the side profile of the log, so that even slight transitions of the sheet are transverse.
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