ELECTRONIC JAM/MISTRIP DETECTION
Original Publication Date: 1980-Jun-30
Included in the Prior Art Database: 2004-Apr-02
Xerox Disclosure Journal
In an electrophotographic printing machine, the presence or absence of a copy sheet on a photoconductive surface can be detected by measuring the shield potential of a dicorotron due to the presence or absence of a copy sheet on the photoconductive surf ace. The shield potential must be increased to maintain constant, dynamic DC current. By interrogating the value of the shield potential at appropriate times, the presence or absence of paper under a specified dicorotron can be determined. For example, as shown in the figure, if no sheet is located on the photoconductive surface, the shield potential will be a first level indicated by reference numeral 10. However, if a sheet of paper is attached to the photoconductive surf ace, the shield potential will rise approximately 400 or 500 volts to a second level indicated by the reference numeral 12. After the copy sheet is stripped from the photoconductive surface, the shield potential will return to the lower level indicated by the reference numeral 14. In this manner, periodic detection of the shield potential provides an indication of whether or not a copy sheet is secured to the photoconductive surface. This arrangement will detect mis-strips and provide a signal indicating the failure of the stripping system to separate the copy sheet from the photoconductive surface.