Patent ID: 7878615

Claim:
An inkjet printhead failure detector system comprising: an inkjet printer including a printhead for printing an image on a substrate, wherein the image has a first sensitive portion and the printhead includes a first portion that prints an area of the substrate corresponding to the sensitive portion of the image; a radiant energy source adapted to radiate electromagnetic energy at a first wavelength; a photodetector located downstream from a printhead of the printer corresponding to the location of a first portion of the printhead, wherein the photodetector is adapted to detect background fluorescence from the substrate at a second wavelength that differs from the first wavelength in the area of the substrate corresponding to the sensitive portion of the image; and a control system connected to the photodetector for determining if fluorescence is radiating from area of the substrate corresponding to the first sensitive portion of the image to indicate that expected quenching did not occur and to indicate an expected failure of the printhead in the first portion of the printhead, and wherein the first sensitive portion of the image is a less than whole portion of the image and the first sensitive portion is required for readability of the image.