Patent ID: 6169355
Filing Date: 2001-01-02
Classification: B41J

Abstract:
An ink jet head having a body, a base attached to said body, said body having a plurality of independent ink compartments each having an inlet orifice, an outlet orifice and a piezoelectric ink actuating element structurally associated with each of said independent ink compartments, said piezoelectric ink actuating element enabling said ink jet head to receive ink from an ink reservoir in fluid communications with said inlet orifice of each one of said plurality of independent ink compartments and then eject droplets of the ink onto a receiver to form an image, said piezoelectric actuating element comprising: (a) a substantially planar piezoelectric transducer comprising a slab of piezoelectric material, said slab of piezoelectric material being formed by sequential layers of different compositions of piezoelectric material, each one of said sequential layers having different d-coefficients defining a functionally gradient d-coefficient throughout said slab, and wherein said slab has a first surface and an opposing second surface, a plurality of spatially separated first electrodes arranged on said first surface, wherein each one of said plurality of first electrodes is operably associated with one of said independent ink compartments, and a second electrode extending substantially lengthwise along the opposed second surface, said piezoelectric material having a functionally gradient d-coefficient selected so that said slab changes geometry in response to an applied voltage which produces an electric field in the slab; and said plurality of first electrodes and said second electrode being arranged so that voltage applied to any one of said plurality of first electrodes and said second electrode induces an electric field in a portion of said slab between said any one of said plurality of first electrodes and said second electrode; and (b) a source of power operably associated with each one of said plurality of first electrodes and to said second electrode of said piezoelectric transducer for enabling fluid flow through any one of said plurality of independent ink compartments, wherein said piezoelectric transducer is actuated for pumping ink out of any one of said independent ink compartments when said source of power applies a voltage to one of said plurality of first electrodes and simultaneously applies a different voltage to said second electrode, the voltage applied to the one of said first electrodes being somewhat lower than the voltage applied to said second electrode; and wherein said piezoelectric transducer is actuated for pumping ink from said fluid reservoir into any one of said plurality of independent ink compartments when said source of power applies a voltage to the one of said plurality of first electrodes and simultaneously applies a different voltage to said second electrode, the voltage applied to the one of said first electrode being somewhat higher than the voltage applied to said second electrode.