Downstream from the trumpet, the sliver runs between two calender rollers which are pressed towards each other. This condensing of the sliver enables more material to be fitted into the cans. Several manufacturers replace the fluted or smooth cylindrical calender rollers with grooved or stepped rollers. Since these latter rollers do not permit the fibers to escape laterally, an even better condensing effect is achieved. In this way, the total filled weight of the can may be increased by up to 20%. Grooved or stepped rollers can be used simultaneously as measuring devices for autoleveling systems. However, this condensing action, with the greater fiber adhesion that results, must be taken into account in further processing. For example, break draft conditions are changed at the roving frame. The break draft distance might have to be increased.