초록 ▼

An inner cylindrical tube has its outer cylindrical surface spaced from an inner cylindrical surface of outer means to have an ink cavity therebetween from which ink is supplied through one or more ink jet nozzles. At least the inner tube is a piezoelectric material so that the inner tube vibrates r

An inner cylindrical tube has its outer cylindrical surface spaced from an inner cylindrical surface of outer means to have an ink cavity therebetween from which ink is supplied through one or more ink jet nozzles. At least the inner tube is a piezoelectric material so that the inner tube vibrates radially when electrically excited to produce vibrations at a desired operating frequency whereby a stream of ink droplets is supplied from each of the ink jet nozzles. The spacing between the inner surface, which has its longitudinal axis coaxial with the longitudinal axis of the inner cylindrical tube, of the outer means and the outer surface of the inner cylindrical tube is selected so that the ink cavity is resonant at the operating frequency of the inner cylindrical tube. To maintain the lowest frequencies of perturbations in the axial direction of the inner cylindrical tube substantially greater than the operating frequency, the inner cylindrical tube can be formed of a plurality of longitudinal segments acoustically isolated from each other in the axial direction. In another form, the outer means is a body formed with a membrane providing acoustical communication from a liquid cavity between the inner tube and the body and each ink cavity, which has ink jet nozzles at its end. The liquid cavity preferably has a liquid of substantially the same density as the ink. This enables each of the ink cavities to have a different colored ink if desired.

대표청구항 ▼

An ink jet head for supplying at least one stream of ink droplets including: outer means having an inner cylindrical surface defining a longitudinal passage therethrough; an inner cylindrical tube disposed within said longitudinal passage in said outer means and having its outer cylindrical surface

An ink jet head for supplying at least one stream of ink droplets including: outer means having an inner cylindrical surface defining a longitudinal passage therethrough; an inner cylindrical tube disposed within said longitudinal passage in said outer means and having its outer cylindrical surface spaced from the inner cylindrical surface of said outer means, said inner cylindrical tube having its longitudinal axis substantially parallel to the longitudinal axis of the inner cylindrical surface of said outer means or coaxial therewith; an ink cavity formed between the outer cylindrical surface of said inner cylindrical tube and the inner cylindrical surface of said outer means and having pressurized ink therein; at least one ink jet nozzle in communication with said ink cavity and from which a stream of ink droplets is supplied; each of said ink jet nozzles having its axis substantially perpendicular to the longitudinal axis of said inner cylindrical tube; and at least said inner cylindrical tube being formed of a piezoelectric material and vibrating radially when electrically excited to produce vibrations within the ink in said ink cavity so that a stream of substantially uniformly spaced ink droplets is supplied from any of said ink jet nozzles.