Roller molds, particularly seamless roller molds, are the key components in a roll-to-roll (R2R) rolling imprinting system which is known for the most effective method for large-area micro-manufacturing. This research has developed an innovative method and implemented it into a prototype system for achieving arbitrary and complicated patterns of 3D microstructures on the surface of a metallic roller. It basically transforms conventional planar photolithography on to the cylindrical surface of a roller through UV exposure, photoresist developing, and etching processes. This roller manufacturing system consists of digital light processing (DLP) technologies, arrayed fiber optics, microlens array, and precision servo-controlled motion systems. Using this arrayed UV beam pen system, we are able to achieve UV patterning on a roll’s surface and finally obtain a seamless roller mold for roller imprinting.