Drop on demand ink jet printing involves the generation of ink droplets and their projection onto a substrate in response to electrical signals generated from a microprocessor. A major factor in controlling the quality of the resultant printed image is the way in which the ink droplet is formed and the consistency of this process.This paper describes the optimisation of the droplet formation process for a piezoelectric ink jet printhead. Taking typical ink as the starting point, a range of polymers with different molecular weights and viscoelastic properties were investigated as potential modifiers of the droplet formation process. The formation and ejection of ink droplets were recorded using visualisation techniques and a structure/property correlation made between the polymer and droplet formation process. An analysis of correlation allows recommendations to be made concerning the selection of suitable polymers for incorporation into an ink formulation, either as binder or as an additive. The efficiency and reproducibility of the droplet formation process is correlated with the print quality of the final image.