1992-08-14
1993-09-07
Rutledge, D.
354331, 354339, G03D 308
Patent
active
052433730
DESCRIPTION:
BRIEF SUMMARY
This invention relates to photographic processing apparatus of a kind having a passage of limited dimensions to define a low volume processing area and adapted in use to receive a photographic solution through which a photographic material to be treated is arranged to pass.
Apparatus of this kind is sometimes referred to as low volume thin tank apparatus and a typical form of the apparatus are described in U.S. Pat. No. 2,186,927 and FR-A-2622708. It has been proposed that in such apparatus the ratio of tank volume to maximum area of material accommodatable therein is shown as being less than 11 dm.sup.3 /m.sup.2 and preferably less than 3 dm.sup.3 /m.sup.2. Replenisher is added to the tank during processing and the volume of replenisher is equal to at least twice and preferably 3 times the tank's volume in less than the time taken for the processing solution's performance to deteriorate beyond predetermined limits of acceptability. The spacings of the inner faces of the longer sides of the processing tank is required to be less than 11 mm and preferably less than 5 mm. The photographic process is to be used is preferably the REDOX amplification process.
One particular advantage of the use of low volume thin tank processing, procedures and apparatus is that the minimum of chemicals is used which has an environmentally beneficial effect since there is less demand on raw material resources and, also, any discharge which has to be treated for pollution potential is reduced to a minimum. Furthermore, the maximum efficiency can be obtained during the process as the low volume of solution used is easily able to be replenished.
A low volume thin tank processing apparatus would normally be made on a maximum width equivalent with the maximum width of material such as paper which is to be passed through it. It will be appreciated, however, that lesser widths of material can be passed through. If this is the case, then the volume of processing solution to the surface area will change away from the optimum. It is an object of the present invention to provide apparatus in which the width is variable so that the chemical effect of the solution is maximised and its quantity is minimised.
There is therefore provided, according to an aspect of the present invention photographic processing apparatus of the kind having a passage which defines a low volume processing chamber and is arranged so that in use it can receive a photographic solution through which a web of photographic material to be treated is arranged to pass, said passage having an inlet and an outlet and opposite side walls which define the effective width of passage, characterized in that at least one side wall is formed by a strip of chemically inert material, said strip of material being so mounted and arranged that it is either replaceable or movable to provide a side wall at a different lateral position to therefore adjust the width of the passage.
Preferably two strips of material are provided, one on either side of the tank so as to define a restricted central passage. These strips may be wound onto rollers external of the tank and the strips may be formed with steps in them so that depending on the width of material to be processed, the appropriate width of strip may be rolled off the rollers into the tank. The strips have a thickness slightly less than the thickness of the passage.
The passage itself may be formed in a narrow flat tank or, alternatively, may define a sinuous path. The sinuous path may be a simple U with the exit and the entrance to the path at the top of the tank. Preferably a central drive roller is provided within the tank to drive the material being processed through the tank. The edges of the tank and the tank width narrowing means may conveniently be provided with grooves or slots to guide the edges of the web being treated.
In order that the invention may be readily understood, one example of apparatus in accordance therewith may now be described with reference to the single schematic FIGURE of the accompanying drawing.
This FIGUR
REFERENCES:
patent: 1178278 (1916-04-01), Uhl
patent: 2186927 (1940-01-01), Hughey
Earle Anthony
Glover Edward C. T. S.
Eastman Kodak Company
Rutledge D.
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