An improved pulley system for use with band printers or the like. A steel printing band is looped around a pair of capstans covered by sleeves made of elastomeric material. The sleeves include a plurality of downwardly angled flexible circumferential flanges and a lower horizontal rim. The band contacts the flanges and as the capstans rotate, inward force on the band is transferred to a downward force by means of the flanges. The downward force causes the band to move into contact with the lower horizontal rim, thereby vertically aligning the band in the printer. In an alternate embodiment, a plurality of non-flexible circumferential ridges are included. The central ridges extend farther out from the surface of the sleeve and serve to define a crown. The sleeve configuration serves to reduce wear and accurately align the printing band within the printer assembly.