m sec regardless of the driving frequency it can be appreciated from the test results that by driving the ink ejection device with the first driving waveform 10 at a temperature under 25 u00b0 c and with the second driving waveform 20 at a temperature above 25 u00b0 c the ink can stably be ejected yet ejecting a large volume of ink droplet specifically there is no substantial variation in the ejection speed regardless of the temperature and the driving frequency in the method of driving the ink ejection device according to this embodiment of the present invention a single positive power source 187 suffices to produce the first and second pulse signals a and b of the first driving waveform 10 and the third and fourth pulse signals c and d of the second driving waveform 20 because those signals have the same positive voltage level v therefore the circuit configuration used in this embodiment is simpler and less costly than the conventional circuit configurations using a voltage variable circuit or more than two power sources supplying different voltages experimental tests were further performed to investigate optimal range of the width wb of the second pulse signal b of the first driving waveform 10 and the time delay d1 fig6 shows evaluation results where the width wb of the second pulse signal b is changed from 0 3 t to 7 0 t and the delay time d1 is changed from 0 3 t to 3 0 t the evaluation is performed by observing the ink ejection speed and the ink droplet volume when the.