A service station for a pen that incldues a treadmill belt that has an outer surface and an inner surface and a pen cap positioned on the outer surface of the treadmill belt, wherein the pen cap is positioend between the treadmill belt and the pen. THe service statin further including two rollers upon which the treadmill belt is mounted, wherein the two rollers contact the inner surface of the treatmill belt for driving the treadmill belt. In addition, there is no device positioned between the two rolelrs that engages the inner surface of the treadmill belt so as to move the outer surface toward the pen. THe service statino further includes a drive axle coupled to one of the rollers and a mechanism for switching a direction of travel of the treadmill belt.