(216ab) Effect of Contact Angle On the Ink Transfer Rate in the Gravure Offset Printing

The gravure offset printing technique has been attracted tremendous attention due to its high throughput and cost-effectiveness for printing process of electronic circuits. A plate-to-plate offset printing equipment was assembled to simulate the gravure offset printing. In addition, the Surface Evolver was used to verify the experiment results. The process of the ink transfer between two plates was deliberately examined by monitoring the dynamic contact angles. For simplicity, water and glycerol were used to emulate the ink. It is found that the correlation between ink transfer rate and the receding contact angle is significant. The transfer rate is large when the liquid droplet is transferred from a substrate (placed on the lower plate) with a higher receding contact angle to a substrate (placed on the upper plate) of a lower receding contact angle. On the other hand, the liquid droplet is hardly transferred from a substrate (placed on the lower plate) with a lower receding contact angle to a substrate (placed on the upper plate) of a higher receding contact angle. The simulation results of the Surface Evolver also confirm this observation qualitatively.