Photography – Fluid-treating apparatus – Having fluid-circulating means
Reexamination Certificate
2000-06-14
2001-09-11
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Having fluid-circulating means
C396S627000, C396S636000
Reexamination Certificate
active
06287026
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the replenishment of processes and is more particularly, although not exclusively, concerned with the replenishment of photographic processes.
BACKGROUND OF THE INVENTION
It is well known that photographic processing solutions need to be replenished periodically in photographic processing apparatus to maintain constant sensitometry for the material being processed. Replenishment is made to the processing solutions so that their chemical composition and activity are kept within specified limits to maintain sensitometry for the material being processed.
The normal method of replenishment of photographic processing solutions in a continuous processor is to add liquids or solids to a processing tank and mix the replenisher into the tank solution by means of pumped recirculation. Replenishers must be at a higher concentration than the tank solution in order to make up for chemical usage by sensitized material which can be either paper or film.
In order to minimize both costs and waste there is a need to shorten process time and also to make more efficient use of the processing chemistry.
SUMMARY OF THE INVENTION
It is an aim of the invention to provide a method of replenishment which will increase the processing speed but will use no more replenisher than methods known in the prior art.
The invention resides in a method of applying replenisher to the emulsion surface of the paper in order to accelerate development. The replenisher can be applied just after the paper has entered the developer or before. Replenisher is applied at a rate equal to or less than the replenishment rate for the paper; which depending on the process is between 30 and 150 ml/sq.m. This solution, which can be a “made-up single solution” or multiple concentrates and water, would under normal circumstances be metered into the developer solution. The replenisher that is applied to the paper ultimately ends-up in the developer solution and the final seasoned position is the same as it would normally be. Since the replenisher is more concentrated than the developer it develops faster and an overall reduction in development time is possible including the replenisher application stage as part of the total time.
The invention is equally applicable to the processing of film, either black or white or color.
In accordance with the present invention there is provided a method of replenishing a processing solution used to process a material having an emulsion surface and a non-emulsion surface, the method characterized by the step of adding the replenisher directly to the surface of the material by means of an applicator positioned on the emulsion side of the material, so as to accelerate processing of the material and maintain sensitometry of said process solution. Preferably the replenisher is applied by means of a foam pad. In one example of the invention the replenisher is applied while the material is in the processing solution. However, the replenisher may be applied immediately before the material enters the processing solution.
The present invention further provides a processing apparatus for processing a material having an emulsion surface and a non-emulsion surface, the apparatus comprising at least one processing stage having a processing solution which is used to process the material, characterized in that the apparatus further includes replenishment means positioned to supply replenisher directly to the emulsion side of the material so as to accelerate processing of the material and maintain sensitometry of the process solution.
The present invention combines the advantages of surface application and tank processing while removing the disadvantages of surface application.
When surface application is used as the only method of processing the initial rate of processing can be high but this rate slows rapidly due to the accumulation of seasoning products in the emulsion layers. This is because the volume applied to the surface is limited compared to a conventional deep tank. Normal replenishment replaces the chemistry used to form the image and is based on average customer density. This average is about 25% of the maximum density, Dmax, over the whole paper area. In a given image it is not known where the regions of maximum density, Dmax, and minimum density, Dmin, are until after processing. This does not matter in a conventional deep tank process since there is a large volume sufficient to process any density of image. If however the complete process is run using only surface application a higher amount of processing chemistry must be spread over the paper so that 100% Dmax can be reached everywhere in the image. The excess chemistry left after surface application cannot be re-cycled. Thus the usage rate is about four times that of a conventional deep tank.
The disadvantages are overcome by the present invention since only part of the process involves surface application and the rest is completed in a conventional tank. The high initial rate of processing with surface application is maintained but the rapid fall-off is avoided due to the paper passing through into a conventional processing tank where seasoning products are dispersed to a normal concentration. Only the normal amount of replenisher is spread over the surface of the paper and any that is unused passes into the tank. Thus the chemical usage is identical to that of a conventionally replenished process. When the present invention is used for replenishing a photographic process the processing time is shortened. The overall chemical usage rates and tank concentrations are unchanged from the usage rates and concentrations of conventional processing systems.
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Eastman Kodak Company
Pincelli Frank
Rutledge D.
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