Photography – Fluid-treating apparatus – Having photographic medium feed
Patent
1998-09-28
2000-06-06
Rutledge, D.
Photography
Fluid-treating apparatus
Having photographic medium feed
396626, 396636, G03D 302, G03D 308
Patent
active
060710209
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to an apparatus for the processing of photographic sheet material, such as X-ray film, pre-sensitised plates, graphic art film and paper, and offset plates. In particular the invention relates to such an apparatus comprising a plurality of closed treatment cells and means defining a sheet material path through the cells in sequence, and to a method of processing photographic sheet material in such an apparatus.
BACKGROUND OF INVENTION
As a rule, a processing apparatus for photographic sheet material comprises several vessels each of which contains a treatment liquid, such as a developer, a fixer and a rinse liquid. As used herein, the term sheet material includes not only photographic material in the form of cut sheets, but also in the form of a web unwound from a roll. The sheet material to be processed is transported through these vessels in turn, by transport means such as one or more pairs of drive rollers, and thereafter optionally to a drying unit. The time spent by the sheet material in each vessel is determined by the transport speed and the dimensions of the vessel in the sheet feed path direction.
In a conventional processing apparatus the sheet material is transported along a generally horizontal feed path, the sheet material passing from one vessel to another usually via a circuitous feed path passing under the surface of each treatment liquid and over dividing walls between the vessels. However, processing machines having a substantially vertical orientation have also been proposed, in which a plurality of vessels are mounted one above the other, each vessel having an opening at the top acting as a sheet material inlet and an opening at the bottom acting as a sheet material outlet or vice versa. U.S. Pat. No. 4,166,689 (Schausberger et al. assigned to Agfa-Gevaert AG) describes such an apparatus.
It is known in the art to perform the rinsing of a silver halide photographic material which has been developed and fixed, by means of a "cascades" rinsing station which comprises two or more rinsing tanks through which the material is passed in succession, the rinsing liquid flowing in counter-current. The advantage is that the last rinsing tank will contain almost fresh rinsing water so that silver effluent will be small. Cascade processing of sheet materials with other processing liquids, such as developers or fixers, also has advantages.
Such a cascade rinsing arrangement is known in which a pump is provided for feeding liquid to the last cell and further pumps are provided for transferring liquid from each cell to its preceding cell. The provision of a pump between each pair of adjacent cells is costly, especially bearing in mind that such pumps represent a significant proportion of the cost of the total apparatus.
While the use of pumps in a horizontal processing apparatus can be avoided by an overflow cascade, liquid levels would be different in different cells and difficult to control in view of surface effects.
OBJECTS OF INVENTION
It is an objective of the present invention to provide an apparatus for the processing of photographic sheet material where the number of pumps used in the apparatus can be significantly reduced while maintaining the advantages of cascade processing.
SUMMARY OF THE INVENTION
We have discovered that this and other useful objects can be realised by the use of closed cells in addition to the provision of a connecting passage leading from a following cell to a preceding cell.
According to a first aspect of the invention there is provided an apparatus for the processing of photographic sheet material comprising a plurality of treatment cells and means defining a sheet material path through the cells in sequence, characterised in that a following one of the cells has a treatment liquid inlet and a treatment liquid outlet, the treatment liquid outlet being connected to a treatment liquid inlet of a preceding one of the cells by way of a connecting passage and in that at least the following cell is a closed cell.
In a
REFERENCES:
patent: 1890026 (1932-12-01), Barkelew
patent: 5108878 (1992-04-01), Nakamura
patent: 5528329 (1996-06-01), Sawada et al.
Bergen Patrick Van den
Verlinden Bartholomeus
AGFA-GEVAERT
Rutledge D.
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