Patent ID: 8509630

Claim:
A method of determining the cause of artifacts in images produced by an electrophotographic (EP) printer, comprising: providing the EP printer with: a print engine for producing an image on a receiving member, the print engine including a plurality of rotatable imaging components; a plurality of runout sensors for measuring the distance between a respective reference point and the surface of the respective rotatable imaging component along a respective reference axis; and an artifact sensor for detecting one or more artifacts, or the absence of artifacts, in the produced image; producing a reference image using the print engine, detecting zero or more artifact(s) in the reference image using the artifact sensor, and storing information identifying the detected artifact(s) in a memory; producing one or more image(s) using the print engine; producing a test image using the print engine and detecting zero or more artifact(s) in the test image using the artifact sensor; determining whether at least one of the detected artifacts in the test image does not correspond to one of the zero or more artifact(s) detected in the reference image using the stored information; if one of the artifact(s) does not correspond: selecting one of the non-corresponding image artifact(s) in the test image; determining a characteristic frequency spectrum of the selected image artifact; rotating at least two of the rotatable imaging components and, while each rotatable imaging component is rotating, measuring the respective distances of the component at a plurality of angles of rotation of the imaging component using the respective runout sensor; automatically determining a respective characteristic frequency spectrum of each measured imaging component using the corresponding measured distances; and automatically comparing the characteristic frequency spectrum of the selected image artifact in the test image to the respective characteristic frequency spectra of one or more of the measured imaging component(s) to determine which imaging component(s) are causing the image artifact.