Patent ID: 6039429
Filing Date: 2000-03-21
Classification: B41J,H05K

Abstract:
A method of detecting an erroneous printing condition in which an print head fires a stream of conductive ink across a transport path of a document processor without a document intercepting the stream of conductive ink, the method comprising the steps of:disposing a substrate across a transport path from a print head so that in a normal printing condition, a document traveling along the transport path is disposed between the print head and the substrate to block the conductive ink from the print head when the print head is activated, and so that in the erroneous printing condition, the ink jet stream passes across the transport path to strike the substrate, the substrate including a first and at least a second conductive path;applying a first voltage potential to the first conductive trace;applying a second voltage potential different from the first voltage potential to the second conductive trace, the second conductive trace being electrically isolated from the first conductive trace;directing the stream of conductive ink against the substrate;biasing the conductive ink to flow between the first and the second conductive traces so as to form a conductive path that facilitates a current flow between the first and the second conductive traces; anddetecting the current flow as an indicator of the erroneous printing condition.