Ink jet method and apparatus for reducing cross talk
AssigneeDataproducts Corporation
InventorStuart Howkins
Life of this patent
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Abstract
An impulse ink jet apparatus includes a plurality of lengthwise expandable piezoelectric transducers, each of the transducers varying the volume of a compression chamber in order to eject droplets of ink therefrom. Mechanical cross talk propagating along a support structure for the transducers is minimized by effectively decoupling each transducer from its neighbors. In one approach, the support structure rigidly supports each transducer at displacement nodal points thereof, while in another approach the lengths of the transducers are uniquely varied with respect to their neighbors.
Claims14
An ink jet apparatus of the drop-on-demand type, comprising:
- an array of variable volume chambers, each of said chambers including an inlet for receiving a supply of ink and an ink droplet ejection orifice;
- a plurality of transducers, each one of said plurality of transducers being adapted to expand and contract along an axis of elongation in response to an electric field that is applied to said transducer substantially transverse to said axis of elongation;
- coupling means being each one of said array of chambers and a respective one of said plurality of transducers for expanding and contracting the volume of each said chamber to eject droplets of ink on demand through its associated orifice, wherein said volume expansion and contraction occurs in response to the expansion and contraction of said respective transducer along said axis of elongation;
- transducer mounting means for rigidly supporting said transducers at displacement nodal points thereof;
- and
- means for applying an electric field to each one of said plurality of transducers such that said transducer contracts along its axis of elongation so as to expand its respective chamber and fill said chamber with ink from said supply through its inlet, and such that said transducers expands along its axis of elongation so as to contract its respective chamber in the absence of said electric field being applied to said transducer so as to eject a droplet from said orifice associated with said transducer on demand.
A method of reducing mechanical cross talk in ink jet apparatus including a print head, a plurality of transducers, attached to the print head, each of which is respectively coupled to an individual ink jet chamber within an array of such ink jet chambers that is formed within the print head, each of the chambers including an inlet for receiving a supply of ink and an ink droplet ejection orifice through which droplets of ink are ejected on demand in response to the volume of the chamber being varied by its respective transducer, wherein the method comprises the step of:
- rigidly supporting each said transducer at a preselected point along its length to to decouple mechanical energy that is produced at resonant frequencies of said transducer from said print head, thereby preventing an activation of one said transducer from causing another said transducer to vary the volume of its respective chamber to eject a droplet of ink, when not demanded, through said orifice.
Dependencies are inferred from the claim text.