Driving technology for prolonging the lifetime of thermal bubble ink-jet printhead

Abstract

Abstract Based upon the purpose of prolonging the lifetime of an ink-jet head, we have attempted to apply doublepulse to a heater during a drop ejection cycle. There are five parameters (pulse widths and voltages and the timedelay) to define the double pulse. Taguchi's method is used to investigate the effects of these parameters. Theexperimental results show that under the optimized condition with (18V,2ps), (14V,4s) and delay time I2jtsdouble pulse can prolong the life of ink jet heads up to an averaged drop counts of 4.8 X 108 as compared with thatof 3.0 x 108 using single pulse. Also, improper parameters can dramatically shorten the life of an ink-jet head, ordisturb the drop fonnation. 1. Introduction In present technologies, all commercial thermalbubble-ink-jet printers employ single energy pulse appliedto a heater such that a bubble is generated on the heated surface of the An ink drop and its followingsatellites are expelled onto a paper by the work of the thermally driven bubble. As soon as the energy input is turnoff, the bubble starts to collapse. The bubble volume shrinks from its maximum value to vanish. During the bubblecollapse, extremely high pressure that occurs within such a short time can severely damage the heater elementsafter a period of operation. II the damage force acting on the heaters can be reduced, the lifetime of an ink-jet headis expected to be prolonged.Based upon the purpose of prolonging the lifetime of an ink-jet head, we have aUempted to apply doublepulse to a heater during a drop ejection cycle. The first pulse is used to generate a bubble to expel a drop onto apaper, just the same purpose as single pulse. The second pulse is used to generate a smaller and lasting longerbubble than the first one, before the vanish of the first bubble. The second bubble can be regarded as a buffer toabsorb part of the damage force resulting from the first bubble collapse. The effect of heater damage due to thepressure wave bombardments generated from sequential bubble collapses can then be slow down. There are fiveparameters (pulse widths and voltages and the time delay) to define the double pulse. Taguchi's method is used toinvestigate the effects of these parameters. Ink-jet heads of HP5 1626A were taken to perform the experiments. Theexperimental results show that under the optimized condition with (18V,2s), (14V,4ps) of double pulse and delaytime 12s can prolong the life of ink jet heads up to an averaged drop counts of 4.8 X