Patent ID: 6206509
Filing Date: 2001-03-27
Classification: B41J

Abstract:
A method of printing using a multi-nozzle ink jet print head having a pressure modulator for causing streams of ink emitted from the nozzles to be broken up into individual droplets, comprising,dividing the nozzles into a plurality of groups of nozzles with each group of nozzles having more than one nozzle,providing corresponding groups of charge electrodes, with each group of charge electrodes having a respective charge controller,generating a modulation waveform during the printing to operate the pressure modulator to cause droplets to be generated in each stream; andindependently for each group of charge electrodes:operating the respective charge controller to supply a charge signal waveform to each charge electrode in turn;adjusting the phase of the charge signal waveform relative to the modulation waveform between 0 and 360 degrees in a number of steps;determining the optimum phase relationship to achieve proper charging for each droplet stream in turn;and thereafter adjusting the phase of the charge signal waveform relative to the modulation waveform to achieve charging of droplets in all the streams in the group simultaneously.