Patent ID: 7809316

Claim:
A transfer apparatus for transferring an image of a developer from an intermediate image-bearing medium onto an image receiving medium, comprising: a pressure member that presses the image receiving medium against the image-bearing medium in a transfer zone; a heating device that heats the image-bearing medium; a power supply device that supplies an adjustable electrical power to the heating device; a first temperature sensor that senses a basis temperature in the vicinity of the image-bearing medium away from the transfer zone and for transmitting to a controller a signal indicative of the basis temperature, wherein said controller is adapted to compute a target temperature difference, said target temperature difference being a difference between a target temperature in the transfer zone and the basis temperature, based on the signal indicative of the sensed basis temperature and the knowledge of the target temperature, said controller being adapted to adjust the electrical power supplied by the power supply device to the heating device to obtain the target temperature in the transfer zone, based on the computed target temperature difference and the result obtained from a calibration procedure that establishes the dependence of the temperature difference between a temperature in the transfer zone and the basis temperature as a function of the supplied electrical power based on temperature readings taken when the heating device is in a first position and a second, different, calibration, position.