Variable focal length acoustic ink printhead

摘要

An acoustic ink printhead has a channel configured to receive ink for printing. The channel has an ink inlet (18) and an ink outlet (20) connected to a recirculating ink pump (14) to promote flow of ink in the channel (26). A plurality of acoustic lenses (28) are positioned adjacent to the channel, with a focal length of at least one of the acoustic lenses differing from focal lengths of the other acoustic lenses to compensate for drop in pressure along the length of the channel. In operation, acoustic energy is directed against the ink surface to cause ejection of individual ink droplets of a predetermined size. <IMAGE>