Developer for photothermographic paper

Abstract

Apparatus is provided for obtaining optimal development of photothermographic paper at different paper speeds and with intermittent paper movement. This is accomplished by a heater platen with plural heaters which are selectively energized in accordance with a function of paper speed. Also a fan for cooling of the platen is selectively energized in accordance with temperature. For this purpose, a temperature signal is produced corresponding to the temperature of each heater and, a speed signal is produced corresponding to the paper speed; if desired, a contrast signal can be produced corresponding to the degree of contrast desired in the development of the paper. A logic device, preferably a microprocessor operating under a program control, processes the signals and controls the energization of the heaters and the fan. More particularly, the platen is heated by plural electrical resistance heaters and is provided with a temperature sensor for each resistance heater. Energizigation of each heater is controlled by the microprocessor to apply voltage pulses at a controlled pulse rate in accordance with temperature. The fan includes an intake and discharge fan for cooling the platen. Energizigation of the fans is controlled by the microprocessor to provide a controlled pulse rate for speed control of the fans. The heater platen is of such construction that it has high thermal conductivity and low thermal inertia to permit fast temperature change.

Dependencies are inferred from the claim text.