Sheet processing apparatus and image forming apparatus

摘要

A sheet processing apparatus includes a folding apparatus 556 which folds a sheet bundle, a switching portion which switches a nipping pressure by the folding apparatus 556 against the sheet bundle, and a flattening apparatus 700 which presses and flattens a folded-back portion of the folded sheet bundle, and the switching portion operates such that the nipping pressure by the folding apparatus 556 against the sheet bundle when the flattening processing is executed becomes weaker than that of the folding apparatus 556 when the flattening processing is not executed.