A doctor blade in flexographic printing is a thin, flexible strip, typically made from steel or polymer, that meters the amount of ink carried by the anilox roll. The anilox roll is a precision-engraved cylinder that holds a measured volume of ink in thousands of tiny cells. As the roll rotates through the ink fountain, the doctor blade presses against its surface and wipes away excess ink, leaving ink only in the engraved cells. This metering step directly controls how much ink transfers to the printing plate and ultimately to the substrate.
Polymer doctor blades, such as the TruPoint line from Flexo Concepts, have replaced traditional steel blades in many pressrooms because they eliminate anilox roll scoring, improve pressroom safety by removing sharp metal edges, and last significantly longer than steel under normal printing conditions.