| 摘要 |
<p>A temperature control system (10) of an automatic film processor (12) includes developer and fixer recirculation paths (30, 40) having thermowell heaters (34, 44) and thermistors (35, 45). The heating rate of a heating cycle is determined based on temperature measurements by the thermistor (35). The duty cycle of heater (34) is controlled in proportion to the difference between measured actual temperature and a preestablished setpoint temperature. When replenishment occurs, until the cooler slug of replenishment becomes mixed, heater duty cycle is chosen based on prereplenishment temperature as well as measured temperature. In a modified embodiment, until the slug is mixed, a single predefined heater duty cycle is set.</p> |
