Patent ID: 6398334
Filing Date: 2002-06-04
Classification: B41J

Abstract:
Process for compensation of a defect in the step by step advance of a print substrate by modifying the arrival position of ink droplets on the substrate (27), these droplets being electrically charged in a variable and sequential manner, the droplets originating from a print head and being charged by charge electrodes (20) connected to a voltage generator (21), the paths of the droplets being affected by deviation electrodes (23, 24) deviating the droplets as a function of their electrical charge to one of N nominal positions defined by their row j, between a first position X1 and a last position XN, and including Nâˆ’2 intermediate positions, the N positions defining a frame in the form of a straight line segment parallel to an X direction of the substrate, characterized in that:a current band is printed with a first mark on the substrate, the substrate is advanced to print the next band, an algebraic difference is determined between a nominal theoretical position of the mark and the real position of the mark, a substrate advance correction is determined for each droplet in a burst, consisting of a dynamic translation correction voltage &phgr; to be applied to the value of the charge voltage to be applied to each droplet output from the head to correct the deviation of the droplets and compensate for the algebraic difference of the position of the substrate from its nominal position, dynamic translation correction &phgr; for the calculated substrate position for the droplet in the said row is applied to each droplet in the next band, in addition to the nominal voltage to be applied to the droplet as a function of its row in a frame.