Continuously operating developing machine with filmstrip tension control

In a continuously operating developing machine of the type comprised of at least one processing fluid stage and at least one drying stage arranged one after the other and means guiding filmstrips along a predetermined winding path through the processing fluid stages and then through the drying stages, in combination, drive rollers at the processing fluid stages for driving filmstrips along the predetermined path through the processing fluid stages, pulling means located downstream of the most downstream drying stage and operative for pulling filmstrips through the developing machine along the predetermined path, and control means operative for keeping the speed at which the drive rollers drive filmstrips through the processing fluid stages higher than the speed at which the pulling roller pulls filmstrips through the drying stages by an amount dependent upon filmstrip tension by varying the speed of the drive rollers in dependence upon filmstrip tension, the control means comprising tension-sensing means operative for sensing the tension in filmstrips travelling through the developing machine at a tension-sensing location intermediate the most downstream processing fluid stage and the most upstream drying stage.

A method of controlling the transport of filmstrips through a continuously operating developing machine of the type comprised of at least one processing fluid stage and at least one drying stage arranged one after the other and means guiding filmstrips along a predetermined winding path through the processing fluid stages and then through the drying stages, the method comprising the steps of pulling filmstrips through the developing machine by exerting upon the filmstrips a pulling force at a pulling location downstream of the most downstream one of the drying stages, sensing the filmstrip tension at a tension-sensing location intermediate the most downstream processing fluid stage and the most upstream drying stage, and varying the pulling force exerted at the pulling location as a predetermined function of the tension sensed at the tension-sensing location.

In a continuously operating developing machine of the type comprised of at least one processing fluid stage and at least one drying stage arranged one after the other and means guiding filmstrips along a predetermined winding path through the processing fluid stages and then through the drying stages, in combination, pulling means located downstream of the most downstream drying stage and operative for pulling filmstrips through the developing machine along the predetermined path, and control means operative for controlling the operation of the pulling means in dependence upon the tension in filmstrips being pulled by the pulling means, the control means comprising tension-sensing means operative for sensing the tension in filmstrips being pulled through the developing machine at a tension-sensing location intermediate the most downstream processing fluid stage and the most upstream drying stage, the pulling means comprising a film-pulling device, a prime mover and a controllable clutch coupling the former to the latter, the control means further including means operative in response to the sensing of a predetermined filmstrip tension value for automatically disengaging the controllable clutch and thereafter upon the elapse of a predetermined time delay also shutting off the prime mover.