SHEET FOLDING DEVICE, POST-PROCESSOR PROVIDED WITH THE SAME, AND IMAGE FORMING SYSTEM

PROBLEM TO BE SOLVED: To provide a sheet folding device, capable of inserting a sheet bundle between a pair of rolls to be folded by a folding blade, without causing position deviation, wrinkles, or breakage in the sheet bundle, so as to achieve excellent finish quality. SOLUTION: A clutch means is provided to be releasably engaged with a roll drive means to make a first and a second folding rolls rotate to follow inserted sheets as the sheet bundle is inserted to a nip position between a pair of folding rolls by means of the folding blade. The sheet folding device is thus provided with a guide means to hold the sheet bundle to a prescribed folding position, the first and the second folding rolls in pressure-contact with each other, the folding blade to insert the sheet bundle supported by the guide means to the nip position of the first and the second folding rolls, a roll drive means to drive the first and the second folding rolls to rotate, a blade drive means to move the folding blade from a stand-by position to the nip position of the folding rolls, and a drive control means to control the roll drive means and the blade drive means. COPYRIGHT: (C)2008,JPO&INPIT