Tympan -

: The tympan acts as a buffer and a distributor of pressure. Without it, the direct force from a scraper bar or platen might damage the paper or produce an uneven ink transfer.

In the world of hand-operated letterpress and lithography, a is a critical component used to manage pressure during the printing process. tympan

: It is a frame over which a taut sheet of parchment, cloth, or heavy oiled paper is stretched. This frame is hinged so it can be folded down over the paper before the final impression is made. : The tympan acts as a buffer and a distributor of pressure

: Printers use the space under the tympan sheet for "packing"—adding layers of paper or board to equalize the pressure across the entire surface of the type. tympan