Patent ID: 7571975
Filing Date: 2009-08-11
Classification: B41J

Abstract:
1. A defect detection device of a print head, comprising: first to Nth (N is a positive integer) actuators providing a driving force for ejecting ink to ink chambers; a vibration signal generator generating vibration signals for vibrating the first to Nth actuators; a switch receiving the generated vibration signals and outputting the vibration signals to a Kth (K is any integer ranging from 1 to N) actuator among the first to Nth actuators; and a defect detector receiving a selected vibration signal of a selected actuator that is made to vibrate by the vibration signals, comparing the received selected vibration signal with a specific vibration signal of the selected actuator, the specific vibration signal of the selected actuator derived from a print head having no defects, and detecting defects in the print head, wherein: the defect detector includes: the selected vibration signal reflects a frequency of an admittance generated by the vibration of the selected actuator, and the defect determination unit determines if the print head has defects depending on whether a selected vibration signal frequency having a largest admittance change corresponds to a specific vibration signal frequency having a largest admittance change.