US Patent 12130572 Determining the existence of defects in print apparatuses

A print apparatus is disclosed. In an example, the print apparatus comprises: a photoconductive surface to receive a latent image representative of an image to be printed onto a printable substrate; a plurality of print components, each print component having a surface movable relative to the photoconductive surface, wherein a current or voltage is to be applied between the print component surface and the photoconductive surface; and processing circuitry to: measure a current or voltage between each print component surface and the photoconductive surface; responsive to detecting a deviation in the measured current or voltage from a reference current or voltage in respect of any of the plurality of print components, determine that there exists a defect associated with the photoconductive surface; and determine, based on the amount of deviation of the measured current or voltage from the reference current or voltage, an indication of the size of the defect.