A modular roll bar assembly for use in a continuous web imaging device includes a plurality of roll bars, a support frame configured to operatively support the plurality of roll bars such that the plurality of roll bars define a web path having a non-linear shape with an entrance end and an exit end, the entrance end being configured to receive a substantially continuous web of substrate material, the plurality of roll bars being configured to guide the continuous web past the exit end, and a temperature control system having a source of thermally controlled air that is configured to supply air at a predetermined temperature and velocity, and a plenum positioned in the support frame that is configured to guide the thermally controlled air from the source to the plurality of roll bars to heat or cool the plurality of roll bars to a predetermined temperature.