An ink-jet printing apparatus was setup to manufacture color filters. The apparatus includes a X-Y- table supporting the substrate, and a set of drop-on-demand ink-jet heads arranged on the adjustable Z-axis for coloring the filter elements. The mechanical motor drivers provide movements for the relative displacement of the substrate with respect to the ink-jet head. A processing of making color filter is discharging the predetermined color ink to the substrate, and then drying the discharged ink to form the color filter pattern. To reduce defective products caused by variance on drop position, this apparatus is additionally equipped with an optical system to detect the substrate position. This system has verified the printing behavior of three commercial print heads, HP51626A, HP51629A, and HP51645A. An image observation of the drop spot center position deviation and spot size deviation were performed. The results show the deviation range of a drop spot is within 4.01 μm, 4.10 μm, and 4.75 μm for HP51626A, HP51629A, and HP51645A, separately. This observation suggests the distance between the substrate and printhead should be closer to hide the satellite spot within main spot. In addition, the drop spot profile needs further study in order to improve its distribution characteristic on a filter element.