......DE....FRGB..IT..............................J0575204EUROPEAN PATENT APPLICATIONA319941207EP93304838.119930621enenen90609119920619US19941207199449199312221993515 5B 41J 2/04 A 5B 41J 2/045 BdeVerfahren zum Betrieb eines Farbstrahls zum Erreichen einer hohen Druckqualität und einer hohen DruckrateenMethod of operating an ink jet to achieve high print quality and high print ratefrMéthode de commande d'un jet d'encre pour réaliser une haute qualité d'impression et un haut débit d'impression1TEKTRONIX, INC.00463982APEP93113Wilsonville Industrial Park, 26600 S.W. Parkway AvenueWilsonville, Oregon 97070-1000USStanley, Douglas M., c/o Tektronix, Inc.26600 S W Parkway Avenue, PO Box 1000, M/S 63-LAWWilsonville, Oregon 97070-1000USRoy, Joy, c/o Tektronix, Inc.26600 S W Parkway Avenue, PO Box 1000, M/S 63-LAWWilsonville, Oregon 97070-1000USSchoening, Susan C., c/o Tektronix, Inc.26600 S W Parkway Avenue, PO Box 1000, M/S 63-LAWWilsonville, Oregon 97070-1000USAnderson, Jeffrey J., c/o Tektronix, Inc.26600 S W Parkway Avenue, PO Box 1000, M/S 63-LAWWilsonville, Oregon 97070-1000USLawrence, Malcolm Graham00047878Hepworth, Lawrence, Bryer & Bizley Merlin House Falconry Court Bakers LaneEpping Essex CM16 5DQGBDEFRGBIT19941207199449

A drop-on-demand ink jet print head (9) has an ink chamber (22) coupled to a source of ink (11), and an ink drop orifice (103) with an outlet (14,14a,14b). An acoustic driver (36) produces a pressure wave in the ink and causes the ink to pass outwardly through the ink drop orifice and outlet (14,14a,14b). The driver is driven with bipolar drive pulses (100) having a refill pulse component (102) and an eject pulse component (104) of a polarity which is opposite to the refill pulse component (102). The refill and eject pulse components are separated by a wait period (106). The drive pulses may be adjusted to minimize their energy content at a frequency corresponding to the dominant acoustic resonance frequency of the ink jet print head (9). This will accelerate drop breakoff, optimize drop shape and minimize drop speed variations over the range of drop printing rates. The size of the ink drops may be varied, such as by driving the acoustic driver (36) with varying drive signals, preferably utilizing individual or combinations of a plurality of bipolar drive pulses (100). The ink jet printer of the present invention may be used to print with a wide variety of inks, including phase change (hot melt) inks to achieve high print quality at high print rates.