Patent ID: 6193343
Filing Date: 2001-02-27
Classification: B41J

Abstract:
A method for driving an ink-jet head including a plurality of ink chambers each partitioned by side walls made of piezoelectric members, the plurality of ink chambers including first ink chambers capable of emitting ink and dummy second ink chambers not capable of emitting ink alternately arranged, and a common ink chamber for supplying ink to the first ink chambers, the method comprising the steps of:generating a drive pulse voltage which is selectively applied to the side walls of the first ink chambers to cause the first ink chambers to emit ink by pressure disturbances;increasing a volume of a given one of the first ink chambers to decrease a pressure therein by an application of the drive pulse voltage;subsequently decreasing the volume of the given one of the first ink chambers to increase the pressure therein by another application of the drive pulse voltage;recovering thereafter an original volume of the given one of the first ink chambers so as to cause an ink drop to be ejected therefrom; andrepeating the increasing, decreasing and recovering steps a plurality of times to eject a plurality of successive ink drops from respective ones of the first ink chambers, while gradually increasing a velocity of the successive ink drops such that later elected ink drops are merged with earlier elected ink drops to thereby form a single ink drop,wherein timings of the drive pulse voltages applied to adjacent ones of the first ink chambers, each of which is arranged adjacent to a respective one of the dummy second ink chambers, are shifted one after another such that a pressure in a first one of the adjacent first ink chambers is decreased whenever a pressure in a second one of the adjacent first ink chambers is increased when the drive pulse voltage is repeatedly applied to the side walls of the first adjacent ink chambers, simultaneously.