Printers for large format printing are either flatbed printers, roll-to-roll printers, or a combination of both.
For flatbed printers, a substrate will be placed on the bed. During the printing process, UV light hits the liquid ink and turns it into solid ink on the substrate. Flatbed printers are usually used to print directly on thicker substrates.
In combination machines, the printers have both removable flatbeds and rolls on each side.