This paper analyzes the relationship between connectivity robustification and coverage control of multi-robot systems. A coverage control is a cooperative task of the system to cover a given area by sensors equipped by the robots, and it requires network connectivity to share the sensing information with each other. Regarding network connectivity, network robustification against robot failure is vital since the robots may fail during their team task. Since the network robustification restricts the configuration space of the robots, we have to pay attention to a quantitative trade-off between the coverage area of a networked multi-robot system and the robustness of the network connectivity. Here we report an analysis result of the trade-off using a one-dimensional network model.