Sheet post-finishing apparatus and image forming apparatus using the same

A sheet post-finishing apparatus which stacks sheets, sent from an image forming apparatus, on a sheet stacking section to form a bundle of sheets, and conducts a saddle stitching process on the formed bundle of sheets, the sheet post-finishing apparatus comprising:

• a stapling device which conducts the saddle stitching process on the bundle of sheets, when the stapling device receives an instruction signal instructing an execution of the saddle stitching process;
• a sheet guide member which is mounted on the stapling device, and which faces a surface of a sheet to be stacked on the sheet stacking section;
• a stapling device moving section which allows the stapling device to move along a line dividing the sheet into two equal portions, perpendicular to a sheet conveyance direction;
• a control section which (i) controls the stapling device to stand by above a lateral center portion of the sheet to be conveyed to the stapling device, while the sheets are stacked to be formed as the bundle of sheets, and after the bundle of sheets has been formed, (ii) controls the stapling device to sequentially move to predetermined plural positions, and therafter, (iii) sends the instruction signal to the stapling device which was stopped at the predetermined plural positions;
• paddles which are mounted at both sides of the stapling device and move together with the stapling device, wherein the paddles rotate to convey a sheet while contacting with a surface of the sheet which is guided by the sheet guide member;
• and
• a paddle driving section which moves together with the stapling device and rotates the paddles.