Notch forming device, bookbinding apparatus and bookbinding system

A notch forming device configured to sequentially receive a plurality of sheets to form a sheet bundle from an image forming apparatus and to form a notch on each of the plurality of sheets, the notch forming device comprising:

• a receiving section which receives information regarding the plurality of sheets and the sheet bundle from the image forming apparatus;
• a notch forming section to form the notch on an edge of each sheet upon receipt of the sheet from the image forming apparatus;
• a shifting section to shift a position of the notch to be formed on the sheet by the notch forming section;
• and
• a control section which controls the shifting section, the control section including:
• a judging section which judges based on the information received from the image forming apparatus whether a sheet on which a notch is currently being formed is a last page of a current sheet bundle currently being output, and which further judges whether a next sheet bundle is to be output after the current sheet bundle, and
• a memory which is coupled to the notch forming section and which memorizes an initial position of a notch to be formed on a sheet of a leading page of a sheet bundle;
• wherein when the judging section judges that the sheet on which the notch is currently being formed is the last page of the current sheet bundle, when the judging section further judges that the next sheet bundle is to be output after the current sheet bundle, the control section controls the shifting section so as to make a notch on a sheet of a leading page of the next sheet bundle at a same position as the initial position memorized in the memory such that a position of the notch formed on the sheet of the leading page of the next sheet bundle is the same as a position of the notch formed on a sheet of a leading page of the current sheet bundle regardless of a number of sheets in the current sheet bundle.