Method and apparatus for feeding replenishment chemicals in film processors

摘要

A photographic processor wherein parallel webs consisting of photosensitive material and/or other material and having identical or different widths are transported lengthwise through one or more liquid baths each of which receives identical quantities of replenishment chemicals at a frequency which insures that the activity of the baths remains unchanged. The device which feeds replenishment chemicals is controlled by a circuit having two inputs one of which receives first signals at a frequency corresponding to the rate of transport of unit lengths of the webs through the bath or baths and the other of which receives cyclically second signals, one for each photosensitive web and each persisting for a period of time which is proportional to the width of the respective photosensitive web. The control circuit causes the feeding device to admit a predetermined quantity of replenishment chemicals in response to the generation of each first signal during the persistence of a second signal. First signals are generated on closing of a microswitch which is actuated by a loop former associated with one of the webs and moving up and down at a frequency which is proportional to the speed of the corresponding web. Second signals are generated by a photoelectric cell which is moved at a constant speed back and forth transversely of the paths of webs and whose transducer reacts only to light which is reflected by a photosensitive web.