Photography – Fluid-treating apparatus – Photographic medium or cartridge sensing
Patent
1998-04-10
1999-12-14
Rutledge, D.
Photography
Fluid-treating apparatus
Photographic medium or cartridge sensing
396570, 396632, G03D 1300
Patent
active
06000861&
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for testing the state of development of a photographic film, the major portion of which is disposed in a light-proof cartridge but which has a leading end that extends out of the cartridge.
When photographic films are processed in large laboratories, the films are removed from the film cartridges in what is called a splicer and cemented together into a long strip. To do this, the trailing end of one film and the leading end of the subsequent film are positioned in a cementing station in such a way that the ends of the respective films can be joined together with a strip of adhesive. Devices of this genus are described in German Published Application No. 3,833,468 and European Published Application No. 0,212,134, for example. The positioning of the films in the splicing station is usually carried out by means of infrared-light barriers.
U.S. Pat. No. 5,093,686 describes a film system and a laboratory organization wherein the film, after being developed and printed, is rewound back into the cartridge and returned to the customer within the original cartridge along with the finished prints. However, this leads to the problem that the laboratory cannot be certain whether a film cartridge that has been delivered to them contains a film that has not yet been developed or an already developed film from which only repeat orders are to be filled.
A splicer that is suitable for such films can be used in darkroom operation, as has been common in the past, to cement the unexposed films into a strip that is then developed in a developing machine. Such a splicer can, however, also be used in a similar way in lightroom operation to splice together into a strip films that repeat orders are to be filled from, whereupon, however, the strip is not to be developed, but printed. If an error occurs during the sorting of incoming film cartridges, such that, for example, a film that has previously been developed is processed with the as-yet undeveloped films or vice-versa, it can lead to the destruction of the incorrectly sorted film. Whereas a film that has already been developed will fade severely when it is developed again, an as-yet unprocessed film that has been mistakenly included with the previously developed films will be exposed as the result of being processed in the lightroom-operation splicer and accordingly completely ruined.
The U.S. Pat. No. 5,521,662 (not a prior publication) discloses a camera. The description mentions an infrared-transmitting sensor that employs various transmission rates to determine whether the film has been developed.
SUMMARY OF THE INVENTION
A principal object of the present invention is therefore to provide a method of and device for reliably determining very early on in the laboratory whether a particular film has or has not been developed.
This object, as well as other objects which will become apparent from the discussion that follows, are achieved, in accordance with the present invention, by positioning the leading end of the film, which extends out of the cartridge, between the source of light and a photosensor; detecting the presence of the film and measuring the transmission of light between the source of light and the photosensor. The state of the film's development is determined by comparing the result of the detection of the presence of the film with that of the measurement. The point of departure for the invention is that a developed film is practically completely transparent, especially in the infrared range of the spectrum, where most standard light-barrier modules operate. It is accordingly impossible with such an infrared-transmitting light barrier to determine whether there is an already developed film or no film at all between the light source and the photosensor. Another detector must accordingly be employed to determine whether or not there is a film in the film guide. Only once this has been confirmed can an infrared light barrier be employed to determine whether the film is transpar
REFERENCES:
patent: 5093686 (1992-03-01), Shigaki
patent: 5521662 (1996-05-01), Suzuki
Wuerfel Reinhart
Zangenfeind Helmut
AGFA-Gevaert Aktiengesellschaft AG
Rutledge D.
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