A sheet postprocessing apparatus includes a magazine unit and a clincher unit. The magazine unit has a driver which is vertically movable relative to a magazine for storing staple sheets. The clincher unit has a clincher holder, a driving mechanism for vertically moving the clincher holder, and a driving source of the driving mechanism. The magazine unit and the clincher unit are disposed vertically opposite to each other. In the sheet postprocessing apparatus, a material to be stapled is inserted between the magazine unit and the clincher unit. The clincher holder of the clincher unit is moved closer to the magazine unit by using the driving source so that a staple may be passed through the material and bent.

In a staple clinching mechanism in a stapler wherein legs of a staple driven in by a driving mechanism are bent in a first direction after the legs of the staple are passed through stacked work sheets, the staple clinching mechanism includes: a pair of movable clinchers; and a pair of curved bend guiding surfaces, for guiding bending the legs of the staple while the movable clinchers are bending the legs of the staple, wherein one of the bend guiding surfaces is inclined in a second direction perpendicular to the first direction.

In a stapling device capable of automatically inserting one or more staples into piled sheets discharged from an image producing device or the like to bind the sheets, a staple driver unit for inserting the staple into the sheet and a clinching unit for bending the leg parts of the staple piercing the sheets are opposed to each other astride a sheet passage and operated to perform stapling by a simple stapling drive having a single power source. By operating the staple driver unit and the clinching unit by the single power source, the precise and stable stapling operation can be carried out with exquisite timing without using a high-level controlling system.

A stapler that requires exertion of less effort comprising a body, an electric motor, a power supply, a power supply switch, a motion transmission mechanism having a gear cluster driven by the electric motor, a staple driving mechanism having a driving blade and a staple magazine driven by the motion transmission mechanism. The motion transmission mechanism comprises a rocking arm, and the rocking arm is a crank which is composed of a connecting shaft and a rocking shaft. The end of the connecting shaft connects to the top of the driving blade. The end of the rocking shaft is a gear, and the gear of the rocking arm has teeth which mesh with teeth of at least one gear of the gear cluster. The motion transmission mechanism comprises a double pole changeover switch and a micro switch.

An electric stapler is provided which comprises a stapler body (10) having a driving-out portion (720) and a driver (321) for driving a staple from the driving-out portion (720) into, for example, sheets of paper while reciprocating. The stapler body (10) includes a table (100) which reciprocates in conjunction with a driving mechanism by which the driver (321) is reciprocated. The sheets of paper are held between the table (100) and the driving-out portion (720) when the table (100) reciprocates. Clinchers (401, 402) are disposed on the table (100). The clinchers (401, 402) clinch the ends of the staple which is driven by the driver (321) and has passed through the sheets. After the sheets of paper are held between the table (100) and the driving-out portion (720), the driver (321) drives the staple into the sheets, and the clinchers (401, 402) are then actuated.