Patent ID: 7396511

Claim:
A dispensing device, comprising: an electrode substrate having a plurality of separate electrodes formed in correspondence with each of a plurality of pressurized chambers to be filled with a solution containing a biological sample; a pressurized chamber substrate disposed so as to face said electrode substrate in a minute gap, having a discharge mechanism for adjusting the pressure inside said pressurized chamber by mechanical displacement of an elastically deforming diaphragm with an electrostatic force corresponding to a potential difference with said separate electrodes, and discharging said solution from a nozzle hole; a drive voltage generation circuit, connected between said diaphragm and said separate electrodes, for applying a drive voltage of a prescribed waveform between said diaphragm and said separate electrodes in order to discharge said solution from said nozzle hole; a current detection circuit, which is connected between said diaphragm and said separate electrodes, configured to detect a current flowing between said diaphragm and separate electrodes during the period from the rising edge of the pulse of said drive voltage to the termination of discharge of the solution; and discrimination means for comparing the detected current with a pre-stored normal current and for discriminating the existence of a defective discharge of the solution as a result of whether a peak waveform of a differential waveform of the current detected during the period with the current detection circuit appears on the positive side two consecutive times.