Patent ID: 8042914

Claim:
A jetting error detector comprising: a plurality of input circuits configured to receive respective voltage values of a plurality of piezoelectric elements from a droplet jetting head configured to jet droplets through a plurality of nozzles by use of the plurality of piezoelectric elements; a selection circuit configured to sequentially select one of the plurality of input circuits; a judging unit configured to judge, based on the voltage value inputted to the selected input circuit, jetting quality of the nozzle for jetting the droplets by use of the piezoelectric element corresponding to the selected input circuit; an output circuit configured to output a jetting quality judgment result of the nozzle; a digital I/O port through which a judgment signal indicating the jetting quality judgment result is outputted from the output circuit; and a unit configured to obtain, based on the jetting quality judgment result, an abnormally applied position in which a jetting error occurs in an application pattern applied by the droplet jetting head, wherein when the judgment signal is an NG judgment signal, a droplet application operation is stopped and the droplet jetting head is controlled by a control unit which receives the judgment signal from the output circuit through the digital I/O port, based on the abnormally applied position, so as to jet and apply droplets again in the abnormally applied position, and the judging unit judges the jetting quality of the nozzle by comparing a threshold and the voltage value, and by comparing a threshold and a power spectrum density value obtained by a Fourier transform of the voltage value.