US3495520A

US3495520A - Photographic processing apparatus

Info

Publication number: US3495520A
Application number: US671083A
Authority: US
Inventors: Ernst Eugen Schumacher
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-09-27
Filing date: 1967-09-27
Publication date: 1970-02-17
Anticipated expiration: 1987-02-17

Description

Feb. 17, 1970 E. E. SCHUMACHER PHQTOGRAPHIC PROCESSING APPARATUS Filed Sept. 27, 1957 R m M w E T SC HUMACHER United States Patent O 3,495,520 PHOTOGRAPHIC PROCESSING APPARATUS Ernst Eugen Schumacher, 3113 Postfach, 6 Frankfurt am Main 1, Germany Filed Sept. 27, 1967, Ser. No. 671,083 Int. Cl. G03d 3/12 U.S.-Cl. 95-94 7 Claims ABSTRACT OF THE DISCLOSURE A continuous photographic film processing apparatus having at least three tanks arranged side-by-side and each containing a processing fluid. The middle one of the tanks has a gas-tight cover extending over the adjacent end of each of the other tanks and also has end walls extending below the surface of the fluid in the other tanks. When film is transported serially through the tanks it must pass under the respective cover and end walls to enter and leave the middle tank. The cover and end walls provide a seal which prevents air from the outside from penetrating into the gas-tight closed space.

BACKGROUND OF THE INVENTION Photographic processors are designed to treat an exposed photographic film in different baths according to a pre-set program. Generally the successive baths are:

(1) A developer-solution to reduce the halogenous silver in the photographic emulsion, where a latent image was produced during the exposure; the developer-solution usually contains reducing agents in combination with stabilizers, an alkali and a moderator;

(2) A fixing bath, dissolving halogenous silver, forming with same a water soluble complex compound;

(3) A water bath for rinsing.

In case of special photographic processes, further baths may be required. Processors are provided with transport or conveyor systems, shifting or carrying the film through the bath tanks and from one to the next in the predetermined sequence.

It is well-known that developer solutions are liable to be deteriorated by oxydation of the reducing agents therein, effected by the oxygen of the air being in contact with the surface of the bath. In case of developers for continuous-tone films, it is, however, possible to counteract oxydation by adding stabilizers to the solution. On the other hand, there are special developers, oxydation of which is nearly impossible to prevent, whenever they come in contact with the air; this is true particularly for socalled lith-type developers, which are indispensable in the technique of process reproduction. The high sensitivity of such lith-type developers to the oxygen of the air is mainly due to their contents of paraformaldehyde or similar products.

SUMMARY OF THE INVENTION The aim of the present innovation is a photographic processor wherein the space above those bath tanks containing oxygen sensitive solution is closed off completely gas-tight from ambient atmosphere, and having means of transport to introduce the films in said baths and to remove them upon completion of the treatment through fluid seal means which prevent air from the outside to penetrate into the gas-tight closed space.

This aim is materialized according to the present invention by a photographic processor, having a roller or belt film-conveyor system, characterized by a construction wherein before and after the tank containing an oxygen sensitive solution, or a multiple of such tanks, there is provided a seal tank containing a solution which is not oxygen sensitive; and wherein at least two gas-tight fences dip into the liquids contained in each one of said seal tanks, the conveyor system leads the film in such a way that it passes underneath said fences dipped into the liquids in the seal tanks, and the fences are fixed to a cover or hood hermetically closing the space not only above the tank or tanks, containing the oxygen sensitive solutions, but also parts of both of the adjacent tanks inside of the said fences.

Preferably the lower edges of said fences will dip at least 10 mm. under bath level of the two fluid-seal tanks, containing the solutions which are not oxygen sensitive.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic side elevational view showing the center part of a photographic film processing apparatus according to the invention, and having three (3) tanks and a roller conveyor system for film transport from tank to tank, and

FIG. 2 is a fragmentary prospective view, with parts broken away, showing details of the gas-tight connection between the sealing end walls of the cover means and the side walls of the sealing tank.

DESCRIPTION OF THE PREFERRED EMBODIMENT The function of the processor embodying this invention may be described, for instance, as follows:

The exposed film is placed on a feeding table of the processor and transferred by the conveyor belt or the conveyor rollers into a first bath, which is not as usual the developer bath, but a mere preliminary or wetting bath, containing a liquid, not sensitive to the oxygen of the air. The film is forced by the conveyor system to pass downwards underneath the first fence, dipped from above into said bath. Having underpassed the fence, the film is lead upwards so as to come out of the first bath and to enter the hermetically closed space, from which it will be introduced in the oxygen sensitive bath, e.g., the developer bath. After passing through the oxygen sensitive bath, the film enters again the hermetically closed space above the oxygen sensitive bath from which it is introduced in the subsequent bath which is not air sensitive, e.g., the stop bath or fixer bath. Here the film is again forced to underpass the fence, dipped therein, so as to come out of the bath in the ambient atmosphere beyond the fence. The further way of the film in the processor is not part of the invention.

As to the composition of the two baths, adjacent to the oxygen sensitive bath or baths, the only condition is that they ought not be air sensitive. In case of the described lith-film development the preliminary 'bath can be functional, but must not be functional in the sense of the developing process. It may be a pure water bath, or containing, in addition, wetting agents or weak alkali, desensitizers or accelerators or even parts of the developer or regenerator, in as far as they are not oxygen sensitive or at least not noticeably sensitive in the dilution or pH range prevailing in the preliminary bath. Also it is possible to use organic liquids, provoking no or only limited swelling effect on the photographic emulsion.

In any photographic development process one or more baths subsequent to the developer bath will be necessary, one of which will not, in any case, be air sensitive. Therefore, no additional tanks or prolongation of the conveyor system is necessary to equip the processor with the hermetically closed space as per the invention. In such cases, the two fences may form part of the cover or hood on top of the tank containing the oxygen sensitive bath.

It is clear, that the hood must be removed in case of cleaning or refilling the machine. Accordingly, in this event, there is atmospheric air in contact with the developer. This will normally be negligible, since it represents only a small quantity of oxygen, which is not renewed in the course of use of the machine, however, the protection of the developer against oxydation can be improved by replacing the residual air in the closed space by an inert gas, such as nitrogen.

The top of the closed space may be dome-shaped or plane, resting on the side walls of the tanks to be covered. Tightening may be obtained by elastic stripes or any other suitable means. Also, the fences must be removably fixed gas-tight to the sidewalls of the tanks and to the top.

In FIG. 1 there is shown the first or preliminary tank 1, the tank 2 containing the oxygen sensitive bath and the tank 3 holding a fixing bath. The film will be transferred along the arrow-marked line by a multitude of rollers or pairs of rollers. The first fence 4 is dipped from above into the tank 1, the lower edge of the fence being at least 10 mm. or more underneath bath level 7. The second fence 5 is dipped into the tank 3. The coverplate 6, in combination with the upper edges of the fences 4 and 5 and the side walls of the tank assembly, forms the closed space into which the film can enter and out of which it can be removed without air penetrating from outside.

FIGURE 2 shows in detail how a gas-tight connection can be obtained between a removable coverplate 6, to which a fence 5 is fixed, and a sidewall 8 of a tank 3. The conveyor rollers are not shown. The cover plate is partly broken away to show details inside the assembly. Angle bars or lugs 9 and 10 are fixed to the side wall 8 in back to back relation to form a channel into which the fence is inserted, and this channel is lined throughout with an elastic or plastic coating material 12 to provide an air-tight seal. The top of side wall 8 is also fitted with a sealing strip, as at 11, on which the cover plate rests by gravity. The nozzles 13 and 13', with suitable valves not shown, permit replacement of the residual air by an inert gas, i.e., by means of a hose from a nitrogen supply connected to one of them. With both valves open, the nitrogen let in one valve will push the air out through the other valve following which both valves will be closed.

I claim:

1. A film processing apparatus comprising at least onebath chamber for containing an oxygen sensitive process ing fluid, means for conveying film into and out of said one bath chamber, first and second sealing chambers respectively disposed ahead and behind said one bath chamber for containing fluid not oxygen sensitive, and a gas-tight closure means for said one bath chamber extending over and enclosing at least the portions of said sealing chambers adjacent said one bath chamber, said closure means having end walls extending into respective ones of said sealing chambers to a point below the normal fluid level therein, and said conveying means extending into and out of each sealing chamber and beneath the respective closure means end wall therein.

2. A film processing apparatus according to claim 1 wherein the" said one bath chamber holds a fluid containing heavy gas.

3. A film processing apparatus according to claim 1 wherein the said one chamber and the sealing chambers are disposed side-by-side within a common housing.

4. A film processing apparatus according to claim 1 wherein the closure means is removable for access to the interior of the apparatus.

5. A film processing apparatus according to claim 4 wherein the closure means end walls have a sliding gastight connection with the side walls of the respective sealing chambers.

6. An apparatus according to claim 1 .wherein the said closure means is provided with a valved gas inlet and a valved gas vent.

7. A continuous film processing apparatus comprising at least one intermediate bath chamber (2) disposed between a pair of end bath chambers (1, 3) all said chambers being disposed side-by-side in a lineal series, and each of said chambers being in the form of an open-top tank adapted to contain fluid to a predetermined level, the edges of the top openings of said chambers being in a common plane. A gas-tight closure means (6) extending from one end chamber to the other in a gas sealing relation with the top edges of all said chambers, said closure means extending over the inner portions only of the end bath chambers and having end walls (4,.5) extending downwardly into the respective end chamber to a point below the normal fluid level (7) therein, and a References Cited UNITED STATES PATENTS 2,389,378 11/ 1945 Marisic.

2,458,394 1/1949 Luboshez -94 XR 3,023,686 3/1962 Meyer 95--94 3,375,593 4/1968 Fleisher et a1. 95-89 XR JOHN M. HORAN, Primary Examiner ROBERT P. GREINER, Assistant Examiner Us. (:1. X.R. 9589