Photography – Fluid-treating apparatus – Having photographic medium feed
Patent
1999-08-20
2000-07-04
Rutledge, D.
Photography
Fluid-treating apparatus
Having photographic medium feed
620617, 620625, G03D 308
Patent
active
060829087
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to the technical field concerning the printing of snapshots on a photosensitive medium.
Particularly, the present invention relates to an apparatus for processing a photosensitive medium, paper or film for instance, carrying a photographic image previously exposed therein.
BACKGROUND ART
It is known that reproducing images on a photosensitive medium, a negative photographic paper for instance, consists of placing said paper in a lightproof room, and then exposing it with light carrying information relative to the image to be reproduced.
Said light can be produced, for instance, by a lamp of a suitable power and colour temperature; it is conveyed by an optical device, through a film carrying a negative print of the image to be reproduced and then to the photosensitive surface of the photographic paper.
According to further reproduction modes, equally known to a skilled technician, the photosensitive medium can consist of autopositive photographic paper, either self-developing or not. It can be exposed by a light source that lights a film carrying the positive image, or by the light directly coming from a subject to be photographed, by means of a suitable photographic camera.
At this point, the image is in a hidden state, and it is subsequently developed and made stable by submitting the photographic paper to suitable chemical processes.
Said processes usually comprise the steps of immersing the photographic paper into a first developing bath, for a first pre-defined period of time, during which the image is developed; the paper sheet is then immersed into a second bath, containing a fixing or bleaching liquid, for a second pre-defined period of time. One or more immersions into a water bath follow, in order to remove the fixing traces. The photographic paper is then dried.
The above described developing process is carried out automatically by known apparatuses, often with some variants and improvements.
Said apparatuses consist of a series of consecutively placed tanks, each containing a suitable processing liquid, at a given temperature, and of dragging members, fit to convey a photosensitive medium into said tanks according to a pre-defined timing. A continuous web made of the above medium, previously exposed with photographic images, is then inserted into the developing tank first, then into the fixing or bleaching tank, and finally into the washing tank. The web is subsequently dried and cut, in order to separate each photogram.
Apparatuses like the one described above require, in order to operate correctly, that each tank is loaded with large quantities of the respective developing product. Said products must be replaced after a given number of operating cycles, since their efficiency tends to decrease; otherwise, small quantities of new product have to be periodically added to the exhausting product. Thus, it is very difficult to keep the physical parameters of the developing products constant, which is necessary to have a constant output quality. Moreover, it is difficult to maintain a constant temperature inside the tanks, which is also very important to achieve good quality printing results. Finally, power consumption is normally high, because big quantities of developing products must be thermoregulated.
A further apparatus for developing a single sheet of photosensitive medium is also disclosed in the Italian patent Application N. B094A 000481, in the name of the same Applicant. Said apparatus is of the so-called micro-tank or laminar tank type, and solves most of the aforesaid problems by using a developing tank having a very small internal volume, which is contained inside a thermoregulating device.
Said developing tank is fit to receive a sheet of photosensitive medium to be processed inside a laminar hollow. It is fed in sequence with developing products, fixing products and washing products, generally in a liquid state, by means of suitable, separate loading means. Each product stays into the tank just for the time required to operate optimal
REFERENCES:
patent: 5477300 (1995-12-01), Fujimoto et al.
Gipco S.r.l.
Rutledge D.
Sapone, Esq. William J.
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