Manufacturing imperfections of photoconductor (PC) drums in electrophotographic (EP) printers cause low-frequency artifacts that could produce objectionable non-uniformities in the final printouts. In this paper, we propose a technique to detect and quantify PC artifacts. A scanner-based system is utilized to scan printed pages of flat-field areas. A wavelet-based filtering technique is applied to the scanned images to isolate the PC-related artifacts from other printing artifacts, based on the frequency range and the direction of the PC defects. The prior knowledge of the PC circumference is utilized to determine the printed area at each revolution of the drum to be analyzed separately. The expectation maximization (EM) algorithm for probability density estimation is applied to the filtered images to model the PC defects as a mixture of three Gaussians. We use the estimated parameters of the Gaussians to measure the severity of the defect. The consistency of the PC artifacts, at subsequent revolutions of the drum, is studied by comparing the models from different revolutions. Results from experiments on different drums and print samples of different tone levels show a high correlation score between the proposed measure and the subjective evaluation of print quality experts.