A new ink transfer model based on the physical mechanism for the maximum ink transfer rate is proposed, and examined by the experimental data of P.J Mangin et, al. for the relations of the maximum ink transfer rates to the printing pressure, the speed and the roughness of paper substrates. The free ink split coefficient and immobilized ink under the maximum ink transfer rate are calculated by the new model and the experimental data. It is concluded that the new model is very useful, and the free ink split coefficient and the immobilized ink are inversely propotional and propotional to the paper roughness respectively and both are saturated eventually under the critical values.