Printing on a large number of units of relatively narrow media accelerates wear on a photoconductor in an electrophotographic imaging device, such as an electrophotographic printer. The accelerated wear results from movement of a cleaning blade over a surface of the photoconductor on regions of the photoconductor...http://www.google.fr/patents/US6108499?utm_source=gb-gplus-shareBrevet US6108499 - Determination of photoconductor wear
