This invention relates to piezoelectric transducer arrangements for ink jet systems and, more particularly, to new and improved ink jet transducer arrangements providing improved performance.
Heretofore, electromechanical transducers such as piezoelectric elements designed to provide one movable wall of an ink chamber in an ink jet system have operated either in an extension mode, such as described in the Howkins U.S. Pat. No. 4,459,601, in which a piezoelectric transducer is expanded upon application of a voltage in a direction perpendicular to the wall of the ink chamber, or in a shear mode, as described in the Fischbeck et al. U.S. Pat. No. 4,584,590, in which the transducer forming a wall of an ink chamber is subjected to a field which causes a shear in the transducer member, forcing a portion of the member to move laterally with respect to the plane of the member. Both of those arrangements not only require a relatively high voltage to produce a desired degree of displacement of a transducer forming the wall of an ink jet chamber, but, in addition, they occupy a substantial volume, causing the ink jet heads in which they are used to be relatively large and heavy, thereby requiring significant driving energy in systems in which the ink jet head is reciprocated with respect to a substrate which receives the ejected ink. In addition, because of the relatively large transducer volume required for each ink jet, the spacing of the ink jets in an ink jet array is substantially larger than the desired spacing of the image lines to be produced during printing with the array.