Apparatus and method for developing a photographic emulsion carrier

Information

  • Patent Grant
  • 6461062
  • Patent Number
    6,461,062
  • Date Filed
    Tuesday, July 10, 2001
    23 years ago
  • Date Issued
    Tuesday, October 8, 2002
    22 years ago
Abstract
An apparatus and method for developing a s photographic emulsion carrier in a plurality of processing tanks through which the emulsion carrier travels in succession, with at least one rotatable roller, the photographic emulsion carrier having a front section and an end section and the roller being arranged such that an end section of the photographic emulsion carrier comes into contact with the roller while travelling from a first to a second processing tank, the direction of rotation of the roller being designed so that the roller can wipe the end section in a direction is away from the emulsion carrier.
Description




FIELD OF THE INVENTION




The present invention relates generally to photographic film developing equipment. More particularly, the present invention relates to an apparatus and method for developing a photographic emulsion carrier.




BACKGROUND OF THE INVENTION




A related art apparatus and method for developing a photographic emulsion carrier are described in DE 43 04 907, corresponding to U.S. Pat. No. 5,414,484. To explain more clearly the problem on which the present invention is based,

FIGS. 1A

to


1


C show a schematic representation of the apparatus known from the related art.





FIG. 1A

shows an emulsion carrier


10


, which is transported from a developer tank


12


to a fixer tank


14


. The two tanks are separated from one another by a partition wall


16


. Two rollers


18


,


20


form a draining roller pair which, besides delivering the emulsion carrier


10


, has the purpose of squeezing the processing fluid from the developer tank


12


from the emulsion carrier


10


prior to the emulsion carrier


10


entering the fixer tank


14


. Guide devices


22


are used to feed the emulsion carrier


10


into an entry roller pair


24


,


26


of the fixer tank


14


. As can be seen from the representation in

FIG. 1B

, the developer fluid is not wiped off fully, so that a developer-fluid residue denoted by


28


remains adhering to an end section


30


of the emulsion carrier


10


. Before the emulsion carrier


10


is immersed in the fixer fluid in the fixer tank


14


, this residue


28


(see

FIG. 1C

) trickles down under the effect of gravity from the end section


30


of the emulsion carrier


10


, along the emulsion carrier


10


, towards its front region while forming drips


31


which may be in the range of several centimeters. Continued developing takes place in the vicinity of the drips


31


, and this is clearly visible on the emulsion carrier


10


as dark regions with a higher optical density, after the complete developing process.




In conventional X-ray examinations, for example of an arm, a leg, the stomach etc., these dark regions are not a great problem since the body region to be examined is normally positioned in the middle of the exposure region. Faults due to the film processor at the edges of the X-ray film, for example scratches, density differences etc., are therefore acceptable to some extent, the diagnosis is not compromised.




The situation is very different for mammography, in which the diagnostic region extends as far as the outermost area of the film. In this case, no faults are therefore allowed. Degradations in the image quality due to the said drips can lead to cases of very serious misdiagnosis.




SUMMARY OF THE INVENTION




The present invention provides an apparatus and method for developing a photographic emulsion carrier, in such a way that it is possible to provide developed emulsion carriers with high imaging quality—especially in the edge region as well—so as to permit use for highly sensitive applications, for example mammography.




A first aspect of the invention provides an apparatus for developing a photographic emulsion carrier in a plurality of processing tanks, through which the emulsion carrier travels in succession, the apparatus including a rotatable roller, the photographic emulsion carrier having a front section and an end section and the roller being arranged in such a way that an end section of the photographic emulsion carrier comes into contact with the roller while travelling from a first processing tank to a second processing tank, wherein a direction of rotation of the roller is designed so that the roller wipes the end section in a direction away from the emulsion carrier.




A second aspect of the invention provides a method for developing a photographic emulsion carrier in a plurality of processing tanks, through which the emulsion carrier, which has a front section and an end section, travels in succession, comprising the following steps:




a) transporting the emulsion carrier from a first processing tank;




b) bringing the end section of the emulsion carrier into contact with a rotatable roller; and




c) rotating the roller in a direction such that the roller wipes the end section in a direction away from the emulsion carrier.




The solution according to the invention is based on the discovery that the formation of drips can be minimized if the fluid accumulating at the end section of the emulsion carrier and adhering there can be wiped off by a roller which rotates away from the emulsion carrier. This very significantly reduces the length of the drips which form and, with optimal design, even prevents any drips from forming.




It is particularly useful if the roller is part of a transport device which is present in any case, or if a roller separately added for the wiping process is coupled to the transport device for moving this roller.




Since the drips are formed on the side of the emulsion carrier where gravity acts, the roller is arranged in such a way that it touches the end section on this side.




If the wiping roller is part of a transport or squeezing device, or if its surface is coupled to the surface of a transport or squeezing roller, then this has the result that the wiping roller is always wetted with fluid. It has been found that this wetting has a positive effect in terms of minor build-up of the fluid accumulating at the end section of the emulsion carrier. This wetting can also be achieved by direct or indirect contact of the roller surface with a roller turning in the bath fluid.




The apparatus according to the invention may also comprise a holder element which can support the emulsion carrier during the wiping. This ensures that the emulsion carrier, especially its end section, is not missed during the wiping process.




The holder element can be produced by configuring one of the guide apparatuses, which are in any case provided, for forwarding the emulsion carrier from one processing tank to the next, in such a way that it can fulfil the function of the holder element.




Of course, the invention also comprises the option that the emulsion carrier may be sent, prior to introduction into the next processing tank, to a separate station in which the wiping process is carried out with a separate roller. It is useful, however, to design the elements which are present in any case, such as transport rollers and guide apparatuses, in such a way that a gap is formed between a roller of the transport device and a guide apparatus serving as the holder element, the guide apparatuses forwarding the emulsion carrier so that its end section enters the gap for the wiping to be carried out.











BRIEF DESCRIPTION OF THE DRAWINGS




These and other features of the invention are set forth in the appended claims. An exemplary embodiment of the invention will be described in more detail below with reference to the appended drawings, in which:





FIGS. 1A

to


1


C represent a schematic representation of the transport of an emulsion carrier in an apparatus known from the related art for developing a photographic emulsion carrier; and





FIGS. 2A

to


2


C represent a schematic representation of the transport of an emulsion carrier in an apparatus according to the invention.











DETAILED DESCRIPTION OF THE INVENTION




In

FIGS. 2A

to


2


C, elements which correspond to those already discussed in connection with

FIGS. 1A

to


1


C are denoted by the same reference numbers.




As can be seen from

FIGS. 2A

to


2


C, the guide apparatus


32


is configured in such a way that the emulsion carrier


10


is not immediately released after leaving the last roller pair


18


,


20


of a developer tank


12


, but rather its end section


30


drops back onto an edge


34


of the guide apparatus


32


and, because of its intrinsic tension, it enters a gap


36


which is formed between the roller


18


and the guide apparatus


32


acting as a holder element. In the gap


36


, the bottom of the end section


30


of the emulsion carrier


10


comes into contact essentially tangentially with the roller


18


. The emulsion carrier


10


pauses for a brief moment in this position, with the roller


18


rotating opposite to the direction the emulsion carrier


10


is transported. By this means the end section is wiped in a direction away from the emulsion carrier


10


, before the emulsion carrier


10


, already gripped by the entry roller pair


24


,


26


of the fixer tank


14


, is transported further. By suitable design of the edge


34


, it is possible to ensure that developer residues possibly remaining on the side of the emulsion carrier


10


facing vertically upwards are wiped off at the edge


34


. As can be seen from

FIG. 2C

, the developer residues


28


present on the bottom of the end section


30


of the emulsion carrier


10


are transferred to the roller


18


and removed by it. This prevents the formation of drips.




The insertion into the gap


36


is effectively helped if the roller pair


18


,


20


is arranged so that the plane defined by the roller axes forms an angle—e.g., between 30° and 60°—with a horizontal plane, the roller


18


being positioned higher than the roller


20


. The result of this measure is that, during the wiping process, the end section


30


of the emulsion carrier


10


comes into contact only with the counter-rotating roller


18


but not with the co-rotating roller


20


.




The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention.



Claims
  • 1. Apparatus for developing a photographic emulsion carrier in a plurality of processing tanks, through which the emulsion carrier travels in succession, the apparatus including a rotatable roller, the photographic emulsion carrier having a front section and an end section and the roller being arranged in such a way that an end section of the photographic emulsion carrier comes into contact with the roller while travelling from a first processing tank to a second processing tank, wherein a direction of rotation of the roller is designed so that the roller wipes the end section in a direction away from a direction of travel of the emulsion carrier.
  • 2. Apparatus according to claim 1, wherein the apparatus further comprises transport devices which deliver the emulsion carrier through the individual processing tanks, the roller being part of one of the transport devices or being coupled to the transport device for moving the roller.
  • 3. Apparatus according claim 1, wherein the roller is arranged in such a way that it touches the end section of the emulsion carrier on the side where gravity acts.
  • 4. Apparatus according to claim 1, wherein the roller is wetted.
  • 5. Apparatus according to claim 1, wherein the apparatus further comprises a holder element for supporting the emulsion carrier during the wiping.
  • 6. Apparatus according to claim 5, wherein the apparatus further comprises a guide apparatus for forwarding the emulsion carrier from one processing tank to the next, the holder element being part of the guide apparatus.
  • 7. Apparatus according to claim 6, wherein the guide apparatus is designed in such a way that a gap is formed between the roller and the holder element, the guide apparatus being capable of guiding the emulsion carrier so that its end section enters the gap for the wiping to be carried out.
  • 8. Method for developing a photographic emulsion carrier in a plurality of processing tanks, through which the emulsion carrier, which has a front section and an end section, travels in succession, comprising the following steps:a) transporting the emulsion carrier from a first processing tank; b) bringing the end section of the emulsion carrier into contact with a rotatable roller; and c) rotating the roller in a direction such that the roller wipes the end section in a direction away from a direction of travel of the emulsion carrier.
  • 9. Method according to claim 8, wherein the end section of the emulsion carrier is supported by a holder element during the wiping.
  • 10. Method according to claim 9, wherein, prior to step c), the end section of the emulsion carrier enters a gap between the roller and the holder element, and is held there during the wiping.
Priority Claims (1)
Number Date Country Kind
100 35 736 Jul 2000 DE
US Referenced Citations (5)
Number Name Date Kind
5063401 Oberkersch et al. Nov 1991 A
5394216 Suzuki et al. Feb 1995 A
5414484 Hofmuth et al. May 1995 A
5634168 Matsumoto et al. May 1997 A
5805949 Nozawa et al. Sep 1998 A