Photography – Fluid-treating apparatus – Single station and plural fluids
Reexamination Certificate
2001-08-01
2003-01-14
Rutledge, D (Department: 2851)
Photography
Fluid-treating apparatus
Single station and plural fluids
C396S634000
Reexamination Certificate
active
06505979
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method and apparatus for processing photographic material. In particular, the invention relates to a method of processing which uses a low volume of processing solution.
BACKGROUND OF THE INVENTION
Conventional processing of photographic material requires the use of large tanks of processing solutions. Each tank contains a processing solution such as developer, bleach, fixing solution or washing solution. The material is transported through each tank in turn. There is a tendency for the solutions to carry over from one tank to another leading to pollution of the solutions. Conventional processing has several other drawbacks. The temperatures which can be utilized are limited and therefore the process is slow. The composition of the solutions must be stable over long time periods in the processing tanks. Replenishment of the solutions is difficult to control. The processing apparatus is also very large due to the number of processing tanks.
To overcome the problems of conventional deep tank processing surface application of the processing chemicals was developed. In previous surface application methods a volume of solution is applied to the surface of the material being processed. However, previous surface application methods have several drawbacks. If the solution applied to the material is just left on the material in a static condition the processing will be very slow and inefficient because there is no agitation and by-products accumulate in the material layers and slow down processing. This method is also prone to non-uniformity of processing.
It is also known to process the material within a rotary tube. The material to be processed is placed emulsion side facing inwards within the tube. Solution is added and the tube rotated. Large volumes of processing solution (70 ml./sq. ft and upwards) will process the material effectively so long as rotation is not so fast as to cause dispersion of the solution puddle. Rapid rotation of the device is however very desirable to quickly and evenly distribute a given small volume of solution over the whole surface of the material so that processing is uniform from one end to the other. If the rotation is too slow there will be seasoning of the small volume of solution by the front end of the material and processing will be different at the back end of the material. Small volumes of processing solution (50 ml./sq. ft or less) do not properly process film or paper because when the device is rotated, even at low speeds of rotation, the solution puddle is dispersed and spread over the whole surface of the material. Consequently there is no agitation. This leads to several processing defects. Processing is streaky, non-uniform and also slow because of local consumption and the accumulation of by-products. There is no surface mixing and chemical economy is therefore low.
The invention aims to provide a method and apparatus in which the above mentioned problems are overcome. The defects can be overcome by using a rotating device in such a way as to provide a means of sweeping the surface of the material to be processed clean of solution at each revolution.
SUMMARY OF THE INVENTION
It is an aim of the invention to provide a processor and a method of processing in which only very small volumes of solution are necessary similar to the volumes used to replenish large tank processors but which gives satisfactory results in terms of sensitometry and uniformity.
The invention provides a method in which a single small volume of processing solution for a given process stage is added to a length of material to be processed and which spreads and mixes the whole volume of the solution continuously while processing is occurring.
A given small volume of processing solution is spread repeatedly over the entire length of the material to be processed. The volume used must be in excess of that which is absorbed by the material. The excess volume required need only be small. The method allows surface application of processing solution but also enables mixing and redistribution of seasoning products.
According to the present invention there is provided a method of processing a photographic material, comprising the steps of loading the material into a chamber adapted to hold the material therein, introducing a metered amount of solution into the chamber, rotating the chamber and continuously sweeping the surface of the material as the chamber rotates to thereby form a wave in the solution through which the material passes, the whole volume of solution for a given stage being spread over the whole material area in a repetitive manner to enable uniform processing.
The present invention further provides an apparatus for processing a photographic material, comprising a chamber adapted to hold the material therein, means for introducing a metered amount of solution into the chamber, means for removing the solution from the chamber, means for rotating the chamber and means for sweeping the surface of the material at each rotation of the chamber, thereby to form a wave in the solution through which the material may pass.
The invention further provides a method of processing photographic material comprising the steps of loading the material onto a carrier with the photosensitive side facing outwards, the carrier resting on drivable rollers such that the clearance between the surface of the material and the rollers is minimal, the rollers being located within a container of processing solution, driving the rollers, the rotation of the rollers causing the carrier to rotate and thus the material to pass through the processing solution, thereby providing agitation and mixing of the solution on the surface of the material to enable uniform processing.
The invention yet further provides an apparatus for processing photographic material, comprising a container for holding processing solution, a number of drivable rollers located within the container, and a carrier for carrying the photographic material with the photosensitive side facing outwards, the carrier resting on the rollers, the drivable rollers and the carrier being spaced such that when the carrier is loaded with the material the gap between the surface of the material and the roller is minimal.
The method and processor of the invention allow uniform and rapid processing to be carried out with only very small amounts of processing solution, in the order of 0.5 to 6 ml./linear foot(1.6 to 19.8 ml/linear meter) of 35 mm film and these volumes can be compared with the replenishment rate for a typical 400 speed color negative film in the industry standard Flexicolor C-41 process of about 6 ml/linear foot. The ability to use very low volumes does not preclude the use of larger volumes in the method and apparatus of the invention although it is not necessary to do so. Only a single processing space is required. The appropriate solution for each processing stage is added and removed sequentially from the processing space. Therefore the processing apparatus may be smaller than those of the prior art.
It is also possible to carry out rapid processing in the processor because the volume used is equal to the replenishment volume used in a conventional deep tank processor and is disposed of after the process. Thus solutions which are stable for only a short time can be used for the development, stop, bleach, bleach-fix, fix and wash stages and any other stage. In addition the temperature in the processor can be much higher than in a conventional large tank processor, up to approximately 80° C., because the solutions are used within a few minutes and then disposed of This avoids any problems of evaporation and crystallization that can occur with large tank processors at high temperatures. Thus high temperature allows more rapid processing. The usage rate of the solutions is no higher than in large tank processors and in many instances can be less. This is particularly true since in the method of the invention processing solutions can be run close to exhaustion which is not possibl
Earle Anthony
Twist Peter J.
Wells Leslie R.
Wildman Nigel R.
Pincelli Frank
Rutledge D
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