1991-08-19
1993-08-31
Rutledge, D.
354322, G03D 308
Patent
active
052413365
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a processing unit and more particularly, but not exclusively, to a processing unit for treating photographic materials.
BACKGROUND OF THE INVENTION
In the field of photographic processing, a photographic material, for example a film, is passed through one or more processing stages. Examples of such stages are development, bleach, bleach-fix, wash, fix and drying. The time spent in each of these stages depends on a number of factors, such as the type of material being processed and the temperature at which processing takes place.
In most existing photographic processing units, the photographic material passes relatively slowly through each stage so that it can spend as long as is desired in that stage, without the necessity of utilizing relatively large apparatus for each stage. This is the situation particularly in the case of minilab processors where it is important to restrict the total physical size of the apparatus as much as possible. This, however, has the disadvantage that the photographic material passes relatively slowly from one stage to the next, thus increasing the lengths of time during which no actual processing takes place.
Furthermore, the critical time in such apparatus is the time from when the first part of a photographic material enters the processor to when the last part of the material leaves the processor. This is known as the "access time". This can be seen to be the same as the sum of the "process time" (the period between the first part of a photographic material entering the processor and that part reaching the exit of the processor) and the time required to discharge the entire material from the processor. The "access time" is clearly increased by a relatively low linear speed.
To reduce the periods of time during which no actual processing takes place, and to reduce the "access time", it is therefore desirable to increase the linear speed at which the photographic material passes from one stage to the next and the rate at which it passes out of the processor.
However, if the path length traveled by the material in a stage is fixed, an increase in linear speed will reduce the period of time that the material spends in that stage. Similarly, altering the time spent by the material in one stage by altering the linear speed in that stage has the effect of altering the linear speed in any subsequent stages.
It is therefore desirable to utilize a system where the time spent in each stage and the linear speed out of the stages can be independently set.
By the very nature of the minilab, film fed in for processing is normally in the form of individual strips, rather than in the form of a continuous web formed of a large number of spliced strips, as is normally the case with large processing units. This necessitates the use of some form of device for feeding the strips into and through the apparatus.
U.S. Pat. No. 3,698,306 describes an arrangement in which photographic material is fed through guide means into a processing station and in which the photographic material is moved at a relatively high speed through the station. After the photographic material has left the station it is deflected by a deflector either back to the entrance of that station or on to the entrance of the next and passes through the atmosphere, even if it is being deflected back to the entrance of that station for a further cycle through that station. This has the disadvantage that no actual processing takes place during a period which is in effect a part of the processing cycle, as well as during the period when the photographic material is passing between stations. Furthermore, periods spent in the atmosphere can have adverse effects. For example developer will become increasingly oxidized.
According to one aspect of the present invention, there is provided apparatus for treating photographic material comprising:
at least one treatment station containing processing solution,
feed means for feeding the material into the treatment station,
cycling means for cyc
REFERENCES:
patent: 3421675 (1969-01-01), Brown et al.
patent: 3698306 (1972-10-01), Fairbanks
patent: 3769897 (1973-11-01), Zwettler et al.
patent: 3785269 (1974-01-01), Morioka
patent: 4156569 (1979-05-01), Fasano
patent: 4185912 (1980-01-01), Schwartz
patent: 4362376 (1982-12-01), Otani
Glover Edward Charles T. S.
Marshall Geoffrey D.
Pummell Leslie J. H.
Ward Paul C.
Bailey Clyde E.
Eastman Kodak Company
Rutledge D.
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