A system and method for adjusting transfer parameters in electrostatic-based printers includes a sensor proximate to a paper path before a toner transfer area. A sensor comprised of opposing conductive plates determines a paper property, such as its capacitance, as it passes through an air gap between the conductive plates. A transfer roller receives an electric charge for transferring toner from an associated transfer belt to the paper with a voltage of the electric charge being adjusted based on a transfer parameter corresponding to the sensor data.