Inkjet jet failures and their detection using piezo self-sensing

As inkjet technology has recently emerged as one of the powerful patterning tools for manufacturing electronic devices, jetting reliability issues have become important. To ensure jetting reliability, jetting monitoring techniques based on piezo self-sensing have been drawn attention to, which detect jet failures due to air bubble entrapment in the printhead. However, the monitoring method based on piezo self-sensing has the capability to detect many other inkjet jet failures. In this study, we investigate the self-sensing signal behaviors in relation to various jet failures other than air bubble entrapment, such as failure of the inkjet head temperature control, abnormal backpressure in the fluidic system, nozzle blockage, etc. To clarify the detectability of various jet failures, we compare self-sensing signals with jet images. From the experimental study, we found that various jet failures can be detected by using the self-sensing signal, and the self-sensing behaviors are different according to the fault causes.