Patent ID: 8290404

Claim:
Electrophotographic printing apparatus comprising: an image-forming member having a surface on which a latent electrostatic image can be formed and developed for transfer of the developed image to a substrate, a developer for depositing onto the surface of the image-forming member a layer of ink comprising charged ink particles to develop the latent image; the developer comprising: an ink bearing surface from which ink is transferred to the image forming member, a cleaner for removing ink from the ink bearing surface, an adjustable power system for generating an electric potential between the ink bearing surface and the cleaner such that charged ink particles remaining on the ink bearing surface after the transfer of ink to the image-forming member are removed from the ink bearing surface through attraction to the cleaner, and a controller arranged to receive measurements of electrical resistance at an interface between the ink bearing surface and the cleaner and to adjust the power system in response to the measurements of electrical resistance to compensate for variations in electrical resistance at the interface such that a desired electric potential between the ink bearing surface and the cleaner is achieved.