An approach for controlling printed line-width in high resolution roll-to-roll gravure printing

One of the challenges in printed electronics is the capacity to print a high resolution electrode. However, it is difficult to gain control over fidelity of microscale line-width of printed patterns especially in roll-to-roll (R2R) gravure printing process. Here, we report a simple solution based on the wettability of ink on the substrate to prevent a widening effect of printed patterns thereby enhancing the precision. The widening effect was found to be affected by intrinsic (ink wetting behavior, cell geometry) and extrinsic (nip pressure, printing speed) conditions. Analysis was conducted to figure out an effect of surface tension of ink and surface energy of substrate on the printed pattern width via contact angle (theta(IS)). For a given cell volume, the width of printed patterns decreased with increasing contact angle. The experimental method was used to determine the optimal extrinsic condition and unstable region border. Finally, we identified three ink setting regions of widening (theta(IS) <= theta(w)(IS,cr)), un-widening (theta(w)(IS,cr) = theta(in)(IS,cr)). The experimental data showed a good agreement with expected results based on the established analytical approach. This result could be used as an important practical guideline to be applied in R2R gravure printing process with high resolution.