Sheet post-processing device and image forming apparatus having the same

An image forming apparatus comprising:

• storage means for storing a sheet;
• sheet supply means for supplying the sheet from the storage means one by one;
• image forming means for forming an image on the sheet supplied from the sheet supply means;
• stacking means for stacking at least one sheet passing through the image forming means;
• transport means for transporting the sheet from the stacking means;
• folding rotating members for folding the sheet by rotation in a state that the folding rotating members nip the sheet transported from the transport means;
• a sheet pushing member for pushing the sheet transported by the transport means toward the folding rotating members by movement relative to the folding rotating members;
• first load means for applying a load to the sheet pushing member pushing the sheet by contacting the sheet at an upstream side of the folding rotating bodies in a direction that the transport means transports the sheet;
• and
• second load means for applying a load to the sheet pushing member pushing the sheet by contacting the sheet at a downstream side of the folding rotating members in the direction that the transport means transports the sheet.