Patent ID: 8422935

Claim:
An image-forming system comprising: an image forming apparatus for forming an image on a sheet for every set of sheets comprising a pamphlet; and a post-processing apparatus for processing a sheet on which an image has been formed, the post-processing apparatus comprising: a folding device comprising two paired folding rollers for folding a sheet, the two rollers being capable of contacting each other and separating from each other, and at least one of the two rollers being rotatable in normal and reverse directions; an interposing device for superimposing a sheet to be interposed on the sheet to be folded; a conveying section for conveying the sheet to be interposed to the interposing device; and an ejection device for ejecting a pamphlet which has been formed by interposing the sheet to be interposed in the sheet to be folded, wherein after the pair of folding rollers conveys the sheet to be folded to a prescribed position while the two rollers are separated, the two rollers press against each other, the at least one of the two rollers changes to rotate in the reverse direction, and the sheet to be folded is folded in a state in which the sheet to be interposed has been made to meet the sheet to be folded by the interposing device, and wherein the interposing device comprises a guide member which guides the sheet to be interposed to the paired folding rollers while supporting the sheet to be interposed after the guide member comes close to the paired folding rollers while pushing the sheet to be folded, and conveys the sheet to be interposed by using the guide member so that a leading edge of the sheet to be interposed meets a folding line of the sheet to be folded and the folding device folds the sheet to be folded whose folding line has been met by the leading edge of the sheet to be interposed, the leading edge of the sheet to be interposed being a front edge thereof when the sheet to be interposed enters the interposing device from the conveying section.