Verfahren zur Rahmensynchro-nization in einem OFDM-System

A photocopy machine is of the type which utilizes a reusable photoconductor and which electrostatically makes copies on plain paper. The drum supports a photoconductor of undeterminate length around the peripheral surface of the drum and includes a supply spool of excess photoconductor mounted within the drum and a take up spool for used photoconductor also mounted within the drum so that the portion of photoconductor positioned around the drum can be periodically replaced. A portion of the drum surface is collapsible and supporting structure is provided at the location where the drum surface collapses to support the photoconductor in a flat plane to permit full frame, flash exposure of the photoconductor. The collapsing of the drum surface and the supporting of the photoconductor in a flat plane are actuated in synchronism with rotation of the drum so that these operations take place when the collapsible portion of the drum is located at an imaging station as determined by the optical path of the photocopy machine.