(1) Offset press. Paste ink, which is filled in Mo Dou, is mostly printed on sheet-fed paper or in rolls. It is a kind of lithographic printing that uses the principle of mutual exclusion of water and oil to print patterns.
(2) gravure press. Liquid ink, ink tank holding ink, roll-to-roll printing, is a kind of intaglio printing which uses the principle similar to yin stamp (not very accurate, but more vivid).
(3) flexo printing machine. Liquid ink, ink tank or closed scraper circulating ink pump, roll-to-roll printing, is a kind of flexible letterpress printing using the principle similar to embossed stamp.
(4) relief machine. Paste ink, Mo Dou ink, roll-to-roll printing, similar to flexography, but the printing plate is hard.
the overall structure of these machines is similar, except that the discharging unit+several printing color groups+receiving unit. Specific differences and their respective characteristics, that is a long story. Look at the scene and study it yourself.