We studied dot formation process of water based ink on inkjet paper. Experimental investigation shows that an ink droplet spreads on paper in several microseconds and penetrates into paper in several miliseconds.
We propose penetration model including void fraction of coated layer, ink fill up ability, ink spreading on paper surface by wetting, and ink penetration velocity. On the basis of the model, computer simulation program has been developed. The simulator can predict dot diameter on coated paper in 10 % error range.