A stapling unit with an improved stitching head drive apparatus includes a bunch sensor that senses the absence of the bunch of sheets and send a signal to the PLC, which actuates a lever operating device. The lever operating device opens the toggle lever by pushing the toggle release lever to disengage the driving lever from the pivot lever. The disengagement of the toggle lever with the pivot lever and the driving lever results in free pivotal movement of the pivot lever and the driving lever will not transfer the motion to the shaft which is responsible to drive the stitching head. Thus, the controllable movement of the stitching head results in improved cycle time of machine and minimum rejection.

A stapling unit with an improved stitching head drive apparatus includes a bunch sensor that senses the absence of the bunch of sheets and send a signal to the PLC, which actuates a lever operating device. The lever operating device opens the toggle lever by pushing the toggle release lever to disengage the driving lever from the pivot lever. The disengagement of the toggle lever with the pivot lever and the driving lever results in free pivotal movement of the pivot lever and the driving lever will not transfer the motion to the shaft which is responsible to drive the stitching head. Thus, the controllable movement of the stitching head results in improved cycle time of machine and minimum rejection.