PURPOSE: To prevent curl and obtain a clear image by providing a sliding contact body sliding contacted with the beltlike photosensitive body of an electrophotographic copying machine at both ends and running at the same peripheral speed as the beltlike photosensitive body.

CONSTITUTION: A driving belt 21 which is extended among the 1st roller 2, the 2nd roller 3, and the 3rd roller 4 for driving and runs as the roller rotates runs to the direction shown by an arrow while carrying the beltlike photosensitive body 1 which is exposed by a flash optical system and is nearly as wide as the driving belt. This curl preventing device consists of a support arm 22 and a couple of detachable sliding contact bodies 23 which slide contacted with the edge of the beltlike photosensitive body 1 while supported by the arm 22. Each sliding contact body 23 consists of a sliding contact belt 26 extended between two small rollers 24 and 25, the sliding contact belt 26 runs at the same speed as shown by an arrow C accompanied with the run of the beltlike photosensitive body 1 to slide contacted with the photosensitive body 1 by its weight, and its surface is consisted of a rugged rubber belt.