Capacitive film position sensing system for a film processor.

摘要

A photographic media position sensing system 10 for use in conjunction with a media processor 16 of the type including a plurality of processing tanks 18A-18D for holding baths 14A-14D of conductive liquid media developing chemicals and a transport mechanism 20A-20D for driving the media 12 through and between the processing tanks. The system 10 includes a plurality of sensing electrodes, each of which is positioned adjacent to one of the processing tanks 18A-18D. One or more ground electrodes 54A-54D are positioned within the processing tanks 18A-18D for making electrical contact with the baths 14A-14D of developing chemicals. Media sensor circuits 40A-40D are connected between the ground electrodes 54A-54D and sensing electrodes 52A-52D. The media sensor circuits 40A-40D provide sensed media signals representative of the presence of media 12 between the sensing electrode 52A-52D and adjacent processing chemical bath 14A-14D as a function of the capacitance between the sensing and ground electrodes. Location identifying circuitry 46 is coupled to the media sensor 40A-40D circuits and provides media location signals as a function of the sensed media signals. A visual display of the positions of the media 12 within the processing tanks 18A-18D is provided by a display 50 interfaced to the location identifying circuitry 46. <IMAGE>