LPI=Lines per inch and refers to the screening when you print. Before the advent of scanners, artwork needed to be broken down into a image made up of dots in order to print, (still does) and you would use a 233lpi, 120lpi, etc. halftone screen. The higher the number, the finer the screen, and the more detail captured. The higher the resolution on the scanner,(DPI) therefore, the more detail that is captured. Also make sure that you check through all the trade magazines before you purchase one. You want to make sure you do not get a inferior product.