1994-05-27
1995-10-17
Rutledge, D.
354330, G03D 302, G03D 304
Patent
active
054595509
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to photographic processing apparatus and is more particularly concerned with the processing of small areas of photographic material, for example, prints on photographic paper.
BACKGROUND OF THE INVENTION
It is well-known to use rotating drums in photographic processing apparatus. US-A-4 613 223 discloses an arrangement in which a flexible sheet of photographic material is driven along an endless curved path within a processing tank by passing the sheet through nips formed between at least one pair of driven rollers. At least one of the driven rollers is the drum itself. During processing, the emulsion (sensitive) surface of the sheet is arranged not to come into contact with any stationary part of the processing vessel as it is being processed. This prevents damage to the surface during processing. After driving the sheet around the endless path for a predetermined number of cycles, which defines the processing time, the sheet is then directed out of the processing tank.
The arrangement described above, has the disadvantage that little or no agitation is applied to the emulsion surface of the photographic material being processed. This may result in uneven processing of the material and variable sensitometry.
Furthermore, relatively large volumes of processing solution are required which makes the arrangement disclosed unsuitable for unstable processing chemistry and single use chemistry as large volumes of processing solutions need to be discarded on a regular basis.
U.S. Pat. No. 2 605 684 discloses an arrangement in which helically wound grooves formed on rollers are used to transfer processing solution from a reservoir and to apply the solution to photographic material being processed. A small portion of the surface of each grooved roller is used to effect such transfer and application.
SUMMARY OF THE INVENTION
U.S. Pat. No. 3 943 541 discloses an arrangement in which a helically grooved roller is used to apply processing solution to photographic material being processed. In this arrangement, processing solution is applied to the surface of the roller from a tank, the material being processed passing over the tank and then roller in turn during processing.
Co-pending British Patent Application No. 9125297.3 (now published International Patent Application No. WO93/11464) discloses a rotating drum arrangement in which low volumes of processing solutions are used allowing unstable and single use chemistry to be efficiently used.
It is an object of the present invention to provide a drum surface for use in the apparatus discussed above which improves the results obtained during processing.
According to one aspect of the present invention, there is provided photographic processing apparatus for processing photographic material, the apparatus comprising
a drum rotatable about an axis and having a surface with at least one helically wound groove formed thereon, the or each helically wound groove having an axis which lies substantially coincident with the axis of the drum;
at least one reservoir for storing processing solution; and
application means for applying processing solution to the surface of the drum for transmittal to the material being processed;
characterized in that the material being processed passes around a substantial portion of the drum surface during processing forming a drum-material interface and in that the or each helically wound groove operates to distribute processing solution at least along the length of the drum-material interface.
In one embodiment of the present invention, one reservoir is provided and comprises a processing tank surrounding at least a part of the drum. In this case, the application means comprises the reservoir.
Alternatively, the application means may comprise at least one feed orifice connected to the at least one reservoir for applying processing solution to the surface of the drum.
In a second embodiment of the present invention, a single feed orifice is provided which is positioned at one end of the drum. In
REFERENCES:
patent: 2605684 (1952-08-01), Nagels et al.
patent: 2861508 (1958-11-01), Baumbach et al.
patent: 3595156 (1971-07-01), Zimmerman
patent: 3673985 (1972-07-01), Dols
patent: 3943541 (1976-03-01), Hirafuji
patent: 4187022 (1980-02-01), Walter
patent: 4613223 (1986-09-01), Cherry et al.
patent: 4954425 (1990-09-01), Iwano
Fyson John R.
Glover Edward C. T. S.
Eastman Kodak Company
Rutledge D.
LandOfFree
Photographic processing apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photographic processing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photographic processing apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-601520