To execute exact search of page information by removing the wrinkles of a page by raising a pair of conveying rollers pinching a page side, as an object for removing its bulge, and temporarily releasing the pinching when the object page is to be pressed towards its tip.
When the sequential controlling for stretching the paginal wrinkles (folding) is executed, paginal turning-over rollers 15 turn to the direction indicated with the arrow 20. Simultaneously, a pair of conveying rollers 6 release the pinching of a booklet through a conveying roller pinching releasing mechanism using a solenoid 21 (the pinching/the releasing of the pinching of the booklet is performed by vertically moving a pair of the conveying rollers 6 through a link mechanism by the turning on/of of the solenoid). As a result, the force being applied to a page with the paginal turning-over rollers 15 is applied starting from a paginal seam, at which a wrinkle most easily tends to develop. Starting from the above state, further, the paginal turning-over rollers 15 rotate towards the direction indicated with the arrow 20, resulting in applying frictional forces towards the tip of the page. In addition, by setting the booklet pinching forces given with a pair of conveying rollers pinchingly fixing the booklet 11 larger than a paginal wrinkle (folding) straightening force 22, the booklet can be fixed immovably.