Mug imprinting roller frame

A curved item printing apparatus has a screen tensioning and printing frame. The frame has a plurality of tensioning devices coupled together by corner members which support the tensioning devices for rotation about their longitudinal axis. Each tensioning device has a screen retainer for retaining an edge portion of a screen fabric. At least one of the tensioning means is a thin edge retainer having a screen engagement edge, a screen engaging surface for directing the screen and a thin edge surface. The screen engaging surface and the thin edge surface converge at the screen engaging end. The perpendicular distance between the longitudinal axis of the thin edge retainer and the thin edge surface is less than the distance between the longitudinal axis and the screen engaging edge.