Restrictors with structure to prevent back flow and inkjet head having the same

Abstract

A restrictor with a structure to prevent a back flow of ink and an inkjet head including the restrictor. In the inkjet head, an ink channel is formed in a channel plate, and the ink channel includes an ink inlet, a plurality of pressure chambers, a manifold, a plurality of restrictors respectively connecting the pressure chambers to the manifold, and a plurality of nozzles. Piezoelectric actuators are formed on the channel plate. Each of the restrictors includes a plurality of protrusions formed on an inner surface thereof in a structure suitable to increase a flow resistance of the restrictor when ink flows from the pressure chamber to the manifold through the restrictor. Each of the protrusions includes a first surface facing a flow of ink moving through the restrictor in a direction from the manifold to the pressure chamber, and a second surface facing a flow of ink moving through the restrictor in a direction from the pressure chamber to the manifold. The first surface has a low flow resistance, and the second surface has a high flow resistance. Therefore, a black flow of ink is restricted when ink is ejected, and sufficient ink can be supplied through the restrictor during an ink refill process.