Sheet post-processing apparatus and image forming apparatus

A sheet post-processing apparatus comprising:

• a first folding portion that forms a first fold on a sheet;
• a second folding portion that forms a second fold on the sheet on which the first fold is formed by the first folding portion;
• and
• a destination switching portion that switches a delivery destination of the sheet on which the first fold is formed by the first folding portion between the second folding portion and a first ejection portion,
• the sheet post-processing apparatus being configured such that a first folding mode or a second folding mode can be selected, the first folding mode forming the first fold but not the second fold on the sheet by operating the first folding portion and switching the delivery destination of the sheet to the first ejection portion with the destination switching portion, and
• the second folding mode forming the first fold and the second fold on the sheet by switching the delivery destination of the sheet to the second folding portion with the destination switching portion and then operating the second folding portion,
• wherein:
• the first folding portion includes a first folding roller pair consisting of a common roller, a first roller, and a first nip formed between the common roller and the first roller, and a blade member that bends and feeds the sheet into the first nip, forms the first fold on the sheet in the first nip, and dispatches the sheet on which the first fold is formed toward the first ejection portion;
• the second folding portion includes a second folding roller pair consisting of the common roller, a second roller, and a second nip formed between the common roller and the second roller, and a feeding portion that bends and feeds the sheet on which the first fold is formed by the first folding portion into the second nip, forms the second fold on the sheet in the second nip, and dispatches the sheet on which the first and second folds are formed toward a second ejection portion;
• the common roller and the first roller are parallel in a sheet conveying direction in a case where the sheet is guided toward the first folding portion;
• an axial direction of the common roller and the first roller is substantially parallel to a conveyance surface including the conveying direction;
• the blade member moves in a direction substantially orthogonal to the conveyance surface;
• and
• the common roller is disposed on an upstream side of the first roller in the conveying direction.