Patent ID: 8731421

Claim:
A method to optimize transfer of a developer fluid having toner embedded in a carrier fluid in an electrophoretic printing apparatus, comprising the steps of: generating charge images of print images being generated on an intermediate image carrier, the print images being inked by electrophoresis into toner images by a developer station with the developer fluid wherein the toner has mobility in the carrier fluid to travel through the carrier fluid onto the image carrier, the toner embedded in the carrier fluid being transported from the developer station to the intermediate image carrier in a first transport path segment; transfer printing the toner images onto a printing substrate at a transfer printing zone by electrophoresis wherein the toner has mobility in the carrier fluid to travel through the carrier fluid onto the substrate, a portion of the carrier fluid depositing on the substrate and into pores of the substrate, the toner embedded in the carrier fluid being transported from the intermediate image carrier to the printing substrate in a second transport path segment; providing a temperature acting on the carrier fluid in the first transport path segment above a melting point of the carrier fluid to provide a first viscosity of the carrier fluid in said first transport path; and providing a temperature acting on the carrier fluid at the transfer printing zone below the melting point of the carrier fluid by setting a temperature of the printing substrate below the melting point of the carrier fluid by cooling the substrate before the substrate reaches the transfer printing zone so that a desired second viscosity of the carrier fluid at the transfer printing zone is provided which is greater than the first viscosity to reduce the portion of the carrier fluid deposited in said pores but still providing a desired wetting of said substrate by said portion of the carrier fluid for transfer of the toner images onto the substrate.