Patent ID: 8208847

Claim:
A sheet folding apparatus comprising: an edge folding unit that folds back a portion on a leading end of a delivered sheet that is to be folded into a regular size and perforated with a filing hole to file the sheet in a regular-size folder, wherein the portion would otherwise block a portion to be punched when the sheet has been folded; a fan folding unit that fan folds the folded-back sheet into a width and length of the regular size to file the sheet in the regular-size folder such that the sheet forms layers along a traveling direction of the sheet; a first punching unit that punches the filing hole in the sheet fan folded into the width of the regular size at the portion to be punched to file the sheet in the regular-size folder; a second punching unit that punches the filing hole in the sheet fan folded into the length of the regular size at the portion to be punched for filing in the regular-size folder; a sheet-processing setting unit that sets a fold mode of the fan fold and selects one of the first punching unit and the second punching unit for use in punching of the filing hole in the sheet based on conditions stored in a memory, the conditions including a size and an orientation of the sheet; and a corner-fold transport path that transports the delivered sheet while aligning a center line thereof with a center line of the corner-fold transport path, wherein the edge folding unit includes a first edge-folding unit that folds a left corner on the leading end of the delivered sheet in relation to the center line of the corner-fold transport path and a second edge-folding unit that folds a right corner on the leading end of the delivered sheet in relation to the center of the corner-fold transport path, and the sheet-processing setting unit selects one of the first edge-folding unit and the second edge-folding unit for use in the corner fold based on the size and orientation of the delivered sheet.