In general, the wet processing of an exposed silver halide photosensitive material (to be simply referred to as a photosensitive material, hereinafter) includes a series of steps, typically development, fixation or bleach-fixation, and water rinsing. The series of steps are usually carried out in an automatic processor by successively transferring the photosensitive material through processing tanks filled with a developer, fixing solution, rinsing water and the like.
The recent general demands for environmental Q maintenance and resource saving are also imposed to this type of processing. In particular, a saving of a developer is a problem. Developing efficiency must be increased before the developer can be saved. It is known that developing efficiency can be increased in fact by using a plurality of developing tanks filled with a divided amount of developer.
It is also known that a saving of rinsing water can be accomplished by providing a plurality of rinsing tanks and effecting rinsing in a counter flow manner, that is, by passing rinsing water in a counter flow to the direction of travel of the photosensitive material.
One approach toward processing with a less amount of processing solution (developer or the like) is a so-called cascade processing system. In the cascade processing system, a plurality of, typically 2 to 9, processing tanks filled with the same type of processing solution are arranged in a side-by-side relationship. The photosensitive material is successively dipped in the tanks by advancing it between adjacent tanks in a crossover manner. In most cases, the processing solution also flows from a tank to a subsequent tank. The flow direction of the processing solution is not definite. With respect to the direction of travel of the photosensitive material, the flow of the processing solution may assume either the same direction, that is, a parallel flow or the opposite direction, that is, a counter flow.
The plurality of side-by-side arranged processing tanks, however, results in an apparatus of an increased size, requiring an increased space for installation. The photosensitive material contacts with air on every crossover movement between adjacent tanks, that is, it has many chances of contact with air during processing. The necessity to compensate for a deterioration by oxidation with air prevents the amount of developer consumed or replenished from being reduced to a desired extent.