For the development of antistatic rubber rollers, we prepared acrylonitrile-butadiene rubbers (NBR)/polyether-based electrolyte blends by mechanical mixing method with different polymerization conditions. The effects of different humidity environment and morphology on the ion-conductive behavior were revealed using DC conductivity measurement system and transmission electron microscopy (TEM). The TEM images showed that the nano-ordered phase separated structure in the blends is formed before the polymerization. The sea-island phase separated structure of the blends could be controlled by polymerization conditions. We also found that there is a crucial relation between the conductive behavior under different humidity conditions and morphology, and the micro-phase separated structure with 10-20 nm-size of polyether islands give rise to the decrease in the difference between conductivities measured in wet and dry conditions. We also prepared vulcanized or cross-linked NBR blends using sulfur or organic peroxide as polymerization initiator. The cross-linked blends with nano-ordered phase separated structure were obtained, which shows good antistatic performance even in the humid condition. In addition, we prepared a plot type rubber roller using the NBR/polyether-based electrolyte blend, and it worked well as an actual printer roller.