The effect of ink drop spreading and coalescing on the image quality of printed cotton fabric

Abstract

Cotton fabric has been extensively used as the substrate of inkjet printing to manufacture traditional garments as well as emerging e-textiles due to its comfort, renewability, good dyeability, biodegradability and relatively low cost. In present work, the spreading and coalescence of ink drops on a cotton fabric as well as their effects on the image quality were investigated. A reactive orange 13 dye was selected as the colorant to make it convenient to observe the depositing morphologies of ink drops. The impacting and wetting processes of an ink drop on a cotton fiber were observed through a high-speed camera. Depositing morphologies of an ink drop, coalescing structures of ink drops and patterns printed with different drop spacings were observed through a microscope. The results show that the ink drop stably deposited on the cotton fabric and formed a long strip pattern after wetting. That indicates the inkjet printing pattern on a cotton fabric should be composed of “line segments” instead of round points. The edges of the pattern printed with a small drop spacing appeared bleeding phenomenon due to the ink drops excessively accumulated on the gaps between cotton fibers. Ink drops could not coalesce at a large drop spacing resulting in the printed pattern being discontinuous. The ideal pattern was printed at an intermediate drop spacing, which was 20 µm in this experiment.