| 摘要 |
PURPOSE:To obtain stable ink jet characteristics by a method wherein a plurality of pulse groups having different pulse peak values are generated by a piezoelectric element, and a temperature is detected in accordance with a waveform outputted through an integrating circuit to switch a heater. CONSTITUTION:When two pulse waveforms having pulse peak values Vp1, Vp2 are inputted to an integrating circuit 2, waveforms integrated to be slow in rising and falling are outputted therefrom. At this time, if pulse widths Pw1, Pw2 of a first pulse and a second pulse are sufficiently smaller than a time constant CR of the integrating circuit 2, the slow pulse rising time results in the pulse height values Vp1, Vp2 being respectively reduced. In a detection circuit 5 provided with a threshold voltage VH, an input voltage Vp is detected if meeting Vp>=VH, but it is not detected if meeting Vp<VH. Therefore, in the detection circuit 5, the first pulse is not detected, but only the second pulse is detected. In a control circuit 6, a heater switching or a drive waveform is controlled in accordance with the state of the pulse detected by the detection circuit 5, and a temperature is compensated in ink jet characteristics. |
