Regular printhead maintenance is essential for reliably providing high quality prints. Epson's Micro Piezo printheads automatically sense the condition of nozzles to maintain high print quality.
In general, inkjet printers use some method to keep nozzles in good working order so that they can eject ink as needed. For example, Epson caps printheads to preserve humidity, maintain the viscosity of the ink in the nozzles and prevent drying so that the nozzles are available when needed. We also provide a system that minimizes the amount of air that dissolves in the ink to limit the formation of bubbles in the ink chambers. In addition, Epson is trying to develop new technology for PrecisionCore printheads that harnesses the capabilities of the piezoelectric elements themselves to improve reliability.
Conceptual image of the residual vibration waveform of a piezoelectric element
Piezoelectric elements flex when a voltage is applied to them. This motion enables them to serve as actuators (i.e., tiny "ink pumps" in each nozzle). Conversely, piezoelectric elements also generate a voltage when they flex. The piezoelectric elements in PrecisionCore printheads are powerful because of the amount they flex. This characteristic means that they can also serve as extremely sensitive sensors that generate voltages corresponding to the amount of flex and that they can be used in diagnosing nozzle health. The piezoelectric elements can determine whether nozzles are ejecting normally and whether bubbles that could prevent ejection are forming. They can also detect potential problems caused by rising ink viscosity. Detection time is measured in thousandths of a second. In other words, PrecisionCore printheads have the ability to self-diagnose their health almost instantly.