Method of retaining a stack of sheets in a post-processing unit

An apparatus for retaining a stack of sheets, the apparatus comprising:

• a) a stack forming unit for forming a stack of sheets;
• b) a wire source for storing a wire, the wire being plastically-elastically deformable;
• c) a selection unit for selecting a retaining element type from one of a clip element type and a stapling element type;
• d) a wire deforming unit configured for, in operation, forming a retaining element of the selected retaining element type by bending and cutting the wire according to a wire deforming program;
• e) a retaining unit for applying the formed retaining element to the stack of sheets;
• and
• f) a control unit for controlling the stack forming unit, the selection unit, the wire deforming unit and the retaining unit for retaining the stack of sheets, wherein the control unit determines the wire deforming program for the wire deforming unit.

A method for retaining a stack of sheets in a post-processing unit, the method comprising the steps of:

• a) forming a stack of sheets;
• b) providing a wire from a wire source, the wire being plastically-elastically deformable;
• c) determining a wire deforming program for forming a clip element;
• d) forming the clip element according to the wire deforming program by bending the wire at a number of positions along the wire and cutting the wire;
• and
• e) applying the formed clip element to the stack of sheets, thereby retaining the stack of sheets.

An apparatus for a retaining a stack of sheets, wherein the apparatus comprises:

• a stack forming unit for forming a stack of sheets;
• a wire source for storing a wire, the wire being plastically-elastically deformable;
• a wire deforming unit configured for, in operation, forming a clip element by bending and cutting the wire according to a wire deforming program;
• a retaining unit for applying the formed clip element to the stack of sheets;
• and
• a control unit for controlling the stack forming unit, the selection unit, the wire deforming forming unit and the retaining unit for retaining the stack of sheets, wherein the control unit determines the wire deforming program for the wire deforming unit.