Folding apparatus and image forming system incorporating same

A folding apparatus configured to stack and fold a designated number of sheets at a time, the folding apparatus comprising:

• a conveyor configured to sequentially convey the designated number of sheets;
• a stacker configured to temporarily store a sheet conveyed by the conveyor to stack the designated number of sheets;
• a sheet folding device configured to fold the designated number of sheets at a time;
• and
• control circuitry configured to
• cause the sheet folding device to fold the stored sheet in response to an occurrence of a sheet jam in processing the designated number of sheets, the sheet jam occurring upstream from the stacker in a direction of sheet conveyance,
• set a first folding position in response to the occurrence of the sheet jam, the first folding position different from a second folding position for a case free from a sheet jam;
• and
• cause the sheet folding device to fold the stored sheet at the first folding position.