Apparatus for printing indicia upon a stationary paper surface and including a rotating pressure ring with the ring being held in a skate assembly having its surface normally forcing the paper to be printed against an ink retaining ribbon, or other character printing medium, and a printer such as a numbering machine. The rotating pressure ring is normally held within a carriage device or the like, such as a skate assembly which carries the rotatable ring. The skate assembly is normally mounted for movement along a backing plate or rail, and motion may be applied to the assembly through any convenient means, including hand motion, or motion achieved for the assembly through mounting upon an endless belt. The pressure ring is driven by means of a pair of rollers which engage the surface of a running rail, or backing plate and thereby provide rotational motion to the rotating pressure ring. The printer assembly of the present invention is particularly adapted for use with either mechanical lettering or numbering machines, as well as for imprinting of individual documents or the like.