PURPOSE: To prevent the floating of the rear ends of copies from a platen, and to realize a good positioning accuracy, by shorten the effective length of a conveying means in order to make the rear ends of all the copies inserted under a covering means, and providing a conveying sensor at the position to detect the front ends of the copies when the rear ends of them come to a specific position of the platen.

CONSTITUTION: A reading standard point is provided at the exhaust side of a platen P, and the interval with a neighboring member Y is made shorter than the length of small copies processed by the device. And a paper exhaust sensor S3 is set at the position to detect the front ends of the copies of all sizes when the rear ends of various sizes of copies reach to stopping standard points Q3 to Q5. After the rear ends of the copies reach on the platen P, the conveying means is moved inversely, and the conveying amount of the conveying means is controlled from the time when the front ends of the copies pass the sensor S3 again, so as to set the front ends of the copies to the setting standard position on the platen P. Consequently, even in the smallest size of copy, its rear end is held by a platen 31 without fail, and the rear end of the copy is never floated up.