① One is a drying device installed between the printing color groups, usually called the inter-color drying device. The purpose is to make the ink layer of the previous color as completely dry as possible before entering the next printing color group, so as to avoid the "mixing" and blocking of the ink color with the previous ink color when the latter ink color is overprinted.

②The other is the final drying device installed after all printing, usually called the final drying device. That is to say, after all the inks of various colors are printed and dried, the purpose is to completely eliminate the solvent in the printed ink layer, so as to avoid problems such as smearing on the back during rewinding or post-processing. However, some types of Flexo Printing Machines do not have a final drying unit installed.