Single component non-magnetic development systems are widely used in desktop laser printers because of their low cost, small size and color printing ability. In particular, non–contact type single component development systems have been studied and developed for several years because of higher resolution printing.The performance of the non-contact type developing systems depends on the property of developing roller, the mechanism of the thin layer forming with metering blade based on the toner formulation. In general, there are two kinds of developing roller for the non–contact type. One is hard roller made of aluminum with a coated layer, and the other is soft roller with a conductive elastic rubber.In recent years, printing speed and resolution in digital printing have been increasing due to various market requirements. However, it is very difficult to have durability at the higher speed because the thinner layer forming should be necessary to prevent toner scattering from developing zone by air flow.Soft developing roller is very useful to reduce toner stress in the thin toner layer. As a result, the durability of the developing system is improved even at higher speed machine.We have designed non-contact type single component non-magnetic development system by experimental design method based on the soft developing roller. We performed experiments using 1200 dpi resolution with parameter values obtained through the optimization process.