Abstract: The physical integrity of a large-scale hardware connection between two modules, such as in the context of high-speed digital printing, is tested by entering a diagnostic mode in which single-instruction handshake routines are repeatedly sent from one module to another through a parallel bus. Each handshake routine activates all of the communication lines in the bus. If a sending module does not receive the expected response to the single-instruction handshake routine within a predetermined time, the sending module causes an audible signal to be emitted. Service personnel can manually manipulate various cables, connectors, and sockets forming a hardware connection while the system is in diagnostic mode, to isolate the location of a hardware fault.

Abstract: An apparatus for mounting a scanner along a paper path in an electrostatographic printing machine for permitting scanning of an information bearing code from a copy sheet traveling in a process direction of travel through the paper path. The scanner mounting apparatus includes a a slidable support platform, for permitting slidable movement of the scanner in a direction transverse to the process direction of travel of a copy sheet, the slidable support platform further having a rotatable housing mounted thereto for permitting rotational movement of the optical scanner in a plane parallel to the copy sheet.

Abstract: A relief device for the tamping mechanism of an offset sheet set stacker. A sheet set stacker is provided having a plurality of retractable tamping mechanisms for alternately offsetting sheet sets within the stacker. Each tamping mechanism is provided with a spring biased follower arm which locks the tamping mechanism in an operative position. A relief device in the form of an oblong pivot mount allows the tamping mechanism to not only pivotally retract from an operative position but to also shift a slight amount transversely to the paper path process direction. This slight shift prevents a binding of the tamper against the just compiled sheet stack and minimizes the occurrence of sheet stack disturbance.