Patent ID: 6447086
Filing Date: 2002-09-10
Classification: B41J

Abstract:
An acoustic printhead comprising:a matrix of drop ejectors configured in rows and columns, each drop ejector including at least a transducer and a switch, wherein when a particular drop ejector is selected, the associated transducer and switch are turned on, and the transducer functions so as to cause the particular drop ejector to eject a drop from a pool of liquid, and when the particular drop ejector is not selected the associated transducer and switch are off, and the particular drop ejector does not eject a drop from the pool of liquid; a plurality of row switches, connected to control operation of the rows of drop ejectors; a plurality of column switches, connected to control operation of the columns of drop ejectors, wherein by selection of an appropriate row switch and column switch, the particular transducer of a specific drop ejector is turned on; a controller connected to the plurality of row switches and the plurality of column switches, to control selection of the drop ejectors; and a compensation network connected to at least one of the rows of drop ejectors and columns of drop ejectors, wherein the compensation network selectively provides compensation energy to drop ejectors which are not selected, to lower undesirable current flow, the compensation network including, a row compensation network including a plurality of row compensation switches coupled to corresponding capacitive elements configured to create a smooth profile of switching ratios by selecting different combinations of capacitors to add compensation paths to transducers on unselected rows; and a column compensation network including a plurality of capacitive elements and a selection circuit configured to dynamically set compensation to a desired value.