PURPOSE: To prevent contact of a separating pawl with a photosensitive body so that no adverse influences are exerted to the photosensitive body by executing the approaching and evading of the separating pawl according to the action and non-action of the separating pawl by the flow and interruption of air flow for air cushion.

CONSTITUTION: The recovering force of a spring 15 for evading the separating pawl pushes back a piston rod 22 extending from a cylinder 16 and evades the separating pawl 1 from the photosensitive body by means of a lever 14 and a shaft 7 when there is no air delivery from an air flow generator 20, i.e., while the separating pawl is not in action. The air flow guided by air paths 18W17 ejects the air from air ejection ports 4 on the surface 3 of the separating pawl 1 which faces the photosensitive body at the time of the action of the separating pawl when the delivery of the air begins. The air past the paths 18W19 enters a cylinder 16 simultaneously and ejects the piston rod 22, thereby moving the separating pawl in the direction approaching the photosensitive body side. The approaching and evading of the separating pawl are thereby automatically executed by the flow and interruption of the air flow. The approaching is released when the air flow is stopped in the event of abnormality. Flawing of the photosensitive body is thus prevented.