Ink jet head

Abstract

The present invention is directed to drop-on-demand ink jet heads. An exemplary form of an ink jet head of the present invention includes a plurality of elongated members formed of piezoelectric material, the elongated members being spaced apart from one another so as to define therebetween a plurality of elongated channels, alternating ones of which are adapted to be filled with ink so as to define ink channels. Electrodes are formed in the channels on opposing sides of the elongated members. A channel closing member is mounted to the elongated members to cover portions of the channels, the channel closing member having nozzle holes formed therein in alignment with at least some of the channels. The elongated members are polarized in at least one direction. The elongated members and the electrodes constitute an ink jetting mechanism for selectively jetting ink from the nozzle holes by selectively changing volumes of the ink channels by either expansion mode or shear mode deformation of selected ones of the elongated members, upon application of a drive voltage to selected ones of the electrodes. The channels which are not adapted to contain ink are dummy channels. Such dummy channels can alternatively be provided outwardly of the group of ink channels, rather than in an alternating succession with the ink channels.