A metal plate, either continuous or segmented, or plastic strip found in the ink fountain of an offset printing press. The fountain blade acts as a barrier between the trough or pan containing the ink, and the fountain roller which transfers ink to the rest of the inking system. The thin gap between the ink fountain and the fountain roller regulates the amount of ink that flows through the press. The width of this gap can be adjusted using the fountain keys, or screws that move either all or portions of the fountain blade toward or away from the fountain roller.
Perhaps the simplest part of an offset press, the fountain blade should not be neglected; dried ink can collect on the bottom of it, preventing the fountain keys from turning properly, and the blade itself (either with age, extreme use, or improper fountain key tightening) can become warped or distorted, preventing effective and accurate control of ink flow. Blade wear can also result in worn corners, causing ink seepage out of the fountain. (See Inking System: Offset Lithography and Offset Lithography.)