Offset Printing is a commonly used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface.
Advantages of Offset Printing compared to other printing methods include:
Consistent high image quality. Offset printing produces sharp and clean images and types more easily than letterpress printing because the rubber blanket conforms to the texture of the printing surface.
Quick and easy production of printing plates.
Longer printing plate life than on direct litho presses because there is no direct contact between the plate and the printing surface. Properly developed plates running in conjunction with optimized inks and fountain solution may exceed run lengths of a million impressions.
The more you print, the less you pay per page, because most of the price goes into the preparation undergone before the first sheet of paper is printing and ready for distribution. Any additional paper print will only cost the client paper price (and ink), which is very minimal.