Patent GB-671170-A (GB)
Title: Improvements in or relating to photographic developing apparatus
IPC: G03D13/06
Filed: 1950-04-28
Abstract: 671,170. Photographic developing apparatus. WIEBALCK,K. April 28, 1950, No. 10571/50. Class 98 (ii). Apparatus for developing photographic film strips comprises a feed compartment for a film-spool which can be made light-tight at least while a spool is present, means for moving a strip from the spool to a developing compartment, and a sleeve mounted in a light-tight bearing for movement from a position in which it is clear of the path between the two compartments, to one in which it surrounds the spool to form a light-tight seal between the two compartments. Packing surfaces may be provided to render the seal fluid-tight. A cutting device may be provided between the two compartments to sever part of the film for separate treatment. The developing tank shown in Fig. 3 has a feed compartment 30 and a developing compartment 29. A film cassette 36 is inserted in a tubular holder 35 and the end of the film 33 is led through a slot in holder 35 to the beginning of a spiral groove 31 in the base of the tank. A light-tight cover 23 with a similar groove 32 is then put on and retained by a funnel 24 screwed to a projection 28 on the base of the tank. A spindle 38 journalled in the base and cover of the tank has sprocket teeth 39 which engage the film perforations. By turning the external knurled end 43 of shaft 38, the film is moved into the grooves 31, 32. A tubular sleeve 47 is threaded in a boss 44 on the cover 23, and is turned by a handle 49 at its closed end 48 to screw it down over the cassette until its surfaces 50 engage liquid-tight packing surfaces 51 on the tank base. The sleeve may carry a circular blade 53 which cuts the film leaving a portion in the cassette. Processing liquid is then poured in through' funnel 24, passing through holes 25 in its neck to the developing compartment. The tank shown in Fig. 8 receives a cassette of the kind having concentric apertured sleeves. The holder 59 is in this case higher and has a cover 67 with a recess engaging a pin 64 on the inner sleeve of the cassette, and a spring-urged pin 69. A small groove 72 in the sleeve 47 engages pin 69 when the cover 23 is put on, so that when sleeve 47 is turned through half a revolution the inner sleeve of the cassette turns to register its aperture with that in the outer sleeve, which is kept stationary by its spring 57 which engages a groove in holder 59. After the film has been fed to the grooves, sleeve 47 is turned back to close the cassette, after which continued movement of sleeve 47 to screw it down forces pin 69 out of groove 72. In another modification, Fig. 12, the cassette holder 94 is rotatably supported on a projection 79 at the centre of a circular tank. Flanges 75, 76 formed with film-supporting grooves 90 and rotatable round the cassette holder are spaced apart by rods 77. A sprocket shaft 84 is journalled in the flanges and carries a gear-wheel 86 engaging a rack 87 round the base of the tank. Flange 76 has a tubular extension 82 in which sleeve 47 is screwed. The cassette is placed in the holder with the film end engaging the sprockets and led into the beginning of the grooves, and a light-tight cover 74 is placed on the tank. The extension 82 is then turned so that flanges 75, 76 and holder 94 turn, and shaft 84 rotates because of the engagement of wheel 86 with rack 87, feeding the film into the grooves. Sleeve 47 is then screwed down, cutting the film by means of knife 53, if required, until its surface 50 meets surface 51 of the cassette holder. Continued turning of sleeve 46 raises the flanges 75, 76 until a surface 93 of the recessed central part of flange 76 meets the lower surface 94 of the cassette holder, and disengages wheel 86 from rack 87. Processing liquid is poured in by a funnel 95. The flanges may be rotated during processing. In further modifications: (1) provision is made for processing unperforated roll-film having a backing paper, the paper being wound on a shaft such as 84 in Fig. 12, but without sprockets, to urge the film into the grooves; (2) the circular blade 51 is omitted, but a metal cylinder is placed over the cassette holder and has a slot through which the film passes, the slot having a sharp.edge to cut the film when the cylinder is rotated; and (3) the sleeve 47 has its upper end screwed for removal so that the cassette can be taken out before liquid is poured in; in this case the seal between the feed compartment and the developing compartment must be light-tight but need not be liquid-tight, so that liquid may be poured in by the feed compartment after removal of the cassette.