Abstract: A mechanical buffer for imparting a substantial delay to paper items, such as envelopes which are being individually and sequentially conveyed in a high-speed paper transport system, maintains physical separation between the conveyed items and does not require termination of item movement or item encoding. The buffer employs a directional translation of item motion, i.e., envelope motion in the length-wise direction is changed to motion in the direction of thickness, to achieve a velocity-distance compression. The buffer apparatus includes a continuous loop of item carriers which are individually positioned to have incoming items sequentially and individually inserted therein, the carriers imposing a retarding frictional force proportional to item thickness and mass to arrest item motion in the longitudinal direction as the direction of item motion undergoes the translation.