Europäisches Patentamt (19) European Patent Office Office européen des brevets (11) EP 0 712 037 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int. Cl.7: G03C 5/38 of the grant of the patent: 15.03.2000 Bulletin 2000/11 (21) Application number: 94117588.7 (22) Date of filing: 08.11.1994 (54) Photographic fixer compositions and method for processing a photographic element Photographische Fixiermittelzusammensetzungen und Verfahren zur Verarbeitung eines photographischen Elementes Composition de fixage photographique et procédé de traitement d'un élément photographique (84) Designated Contracting States: (74) Representative: DE FR GB IT Parent, Yves et al KODAK INDUSTRIE, (43) Date of publication of application: Département Brevets, 15.05.1996 Bulletin 1996/20 CRT - Zone Industrielle 71102 Chalon-sur-Saône Cedex (FR) (73) Proprietor: EASTMAN KODAK COMPANY (56) References cited: Rochester, New York 14650-2201 (US) • RESEARCH DISCLOSURE, no.187, November 1979, HAVANT GB pages 625 - 626 C J (72) Inventors: BATTAGLIA ET AL 'Hardening fix baths for use in • Faranda, Filippo photographic processing' 3M Italia Ricerche S.p.A. • RESEARCH DISCLOSURE, vol.167, March 1978, Ferrania (Savona) (IT) HAVANT GB page 40 ANONYMOUS 'Hardening • Buruano, Franco fixers' 3M Italia Ricerche S.p.A. • DATABASE WPI Section PQ, Week 9402, Ferrania (Savona) (IT) Derwent Publications Ltd., London, GB; Class • Marchesano, Carlo P83, AN 94-013478 & JP-A-5 323 525 (FUJI 3M Italia Ricerche S.p.A. PHOTO FILM CO. LTD.) 7 December 1993 Ferrania (Savona) (IT) Remarks: The file contains technical information submitted after the application was filed and not included in this specification Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 0 712 037 B1 Printed by Xerox (UK) Business Services 2.16.7/3.6 EP 0 712 037 B1 Description BACKGROUND OF THE INVENTION 5 [0001] In processing photographic films, especially X-ray films, it is highly advantageous to complete the processing in a very short period of time. To accomplish this objective, it is common practice to process such films using a roller transport processor and to carry out the processing without an intervening washing step between the steps of develop- ing and fixing. This method of processing is described, for example, in US 3,545,971. To facilitate the use of a roller transport processor, both the developer and the fixer typically contain a hardening agent, with the hardening agent usu- 10 ally being an aldehyde in the developer and an aluminum salt in the fixer. Boric acid is often incorporated in the fixer used in the aforesaid process to prevent the formation of sludge resulting from precipitation of aluminum hydroxide when the fixer is contaminated by developer carry-in. Such use of boric acid is described, for example, in US 4,046,570. The hardening fixer composition described in this patent also contains a 1-hydroxy-alkylidene diphosphonic acid, in which the alkylidene group contains from 2 to 5 carbon atoms to retard formation of aluminum hydroxide. The 1- 15 hydroxy-alkylidene diphosphonic acid partially or completely replace boric acid in the hardening fixer composition. [0002] Another method to reduce the precipitation of aluminum hydroxide has been described in Research Disclosure 17549, wherein a combination of a diphosphonic acid, such as a hydroxyalkylidene diphosphonic acid, and an aminop- olycarboxylic acid, such as a 1,3-diamino-2-propanol tetraacetic acid, has the tendency for aluminum hydroxyde precip- itates, as a result of carrying of aluminum salt hardening agent contacting in the hardening baths. The diphosphonic 20 acid and the aminopolycarboxylic acid are effective in the stabilizing bath in small concentrations such as amounts of each of about one gram per liter or less. The pH of said color stabilizing bath is in the range from about 6 to about 11. [0003] Japanese Patent Application 05-323,525 describes a black-and-white fixer solution comprising aminopolycar- boxylic acids and/or phosphonic acids as chelating agent, preventing the water fur and odour. The fixer composition is substantially free of ammonium ions and substantially free of aluminum hardener, the amount of the hardener being 25 lower than 0.01 mol/l that is the minimum amount known in the art to give the fixer composition a hardening activity, as described in Research Disclosure 16768 and in US 4,046,570. [0004] To further promote the objective of a very short total processing time, it is advantageous to employ ammonium thiosulfate as the fixing agent, because it acts more rapidly than alternative fixing agents such as sodium thiosulfate, as described in GB 1,290,026. Thus, a particularly desirable fixer is one which contains ammonium thiosulfate and is free 30 of boric acid; however, it has been found that a very serious problem of crystal formation occurs. In particular, crystals are deposited from the fixer on the walls of the fixer tank and on the roller assemblies. In addition, the crystalline deposit displays a tendency to absorb additional fixer, thereby resulting in movement of "creep" along processor parts and tank walls. Research Disclosure 18728 discloses a number of agents incorporated in the hardening fixer and which sup- press crystal formation. Useful agents are, for example, aminopolyphosphonic acids, such as diethylenetri- 35 aminepentamethylenephosphonic acid, and aminopolycarboxylic acids, such as 1,3-diamino-2-propanol tetraacetic acid. [0005] EP 486,909 describes ammonium-free fixing bath containing a complex building agent, e.g., nitrilodiacetic monopropionic acid, useful for silver halide photographic materials. The baths exhibit good fixing speed and no depo- sition. 40 [0006] The pH of these fixer baths is normally around 4.00-4.30, because at higher pH, expecially more than 5.00, there is precipitation of Al(OH)3. On the other hand, lower pH is correlated with high SO2 evolution, which is environ- mentally dangerous. It could be useful to have a photographic fixer composition showing a reduced tendency to form an aluminum hydroxyde precipitation at pH values higher than those of standard fixer compositions. In fact, a fixer com- position working at said high pH value could be also advantageous from an environmental point of view, showing a 45 reduced SO2 emission. SUMMARY OF THE INVENTION [0007] A photographic fixer composition is described in the present invention, said composition comprising a silver 50 halide solvent, an aluminum salt hardening agent, a buffering agent and ammonium ions in amount of at least 0.20 mol/l, at least an aminopolycarboxylic acid sequestering agent of formula (I-a) or (I-b) or a water-soluble salt thereof and at least a polyphosphonic acid sequestering agent of formula (II-a), (II-b), (II-c), (II-d') or (I-d''): 55 2 EP 0 712 037 B1 5 10 15 20 25 wherein X is an unsubstituted alkylene group having 1 to 4 carbon atoms; R3 and R4, equal or different, each represent hydrogen or -CH2-R1 and R1 and R2, equal or different, each represent -COOM, wherein M represents a hydrogen atom, a sodium atom, a potassium atom, a lithium atom or a quaternary ammonium group (such as ammonium, pyrid- 30 inium, triethanolammonium or triethylammonium); 35 wherein M is as above and R5 is an alkyl group, an aryl group, an aralkyl group, an alkaryl group, an alicyclic group or a heterocyclic radical, and R5 can be further substituted with substituents suchs as hydroxyl, halogen, an alkoxy group, 40 a - PO3M2 group, a -CH2PO3M2 group, or an -N-(CH2PO3M2)2 group; 45 50 wherein M is as above and R6 is an alkyl group, preferably of one to five carbon atoms, 55 3 EP 0 712 037 B1 wherein M is as above and R7, R8 and R9 are hydrogen or an alkyl group, preferably alkyl of one to five carbon atoms, and 5 10 wherein R12, R13 and R14, equal or different, each represent a hydrogen atom or a -PO3M2 group, wherein M has the same meaning of above, and R10 and R11, equal or different, each represent a hydrogen atom, an alkyl group, a - PO3M2 group or a PO3M2 substituted alkyl group, and Q represents the atoms or chemical bonds necessary to com- 15 plete a 3- to 6- membered ring, with the proviso that at least two of R10, R11, R12, R13 and R14 substituents represent a -PO3M2 group. [0008] The present invention also provides a method of processing an exposed photographic silver halide element comprising the steps of developing by means of a developer comprising a silver halide developing agent and treating the developed element with a fixer composition, wherein the fixer composition is one described above. 20 [0009] The photographic fixer composition of the present invention shows a reduced tendency to form an aluminum hydroxyde precipitation than standard fixer compositions; in addition, the fixer composition of the present invention shows a reduced SO2 emission because it is able to work well at pH values higher than standard values. DETAILED DESCRIPTION OF THE INVENTION 25 [0010] The hardening agent contained in the photographic fixer composition of the present invention is an aluminum salt hardening agent; it is of the kind generally used in acid hardening fixers which include soluble aluminum salts or complexes like aluminum chloride, aluminum sulfate and potassium or ammonium alum. The amount of aluminum salt hardening agent is dependent on the desired hardening effect which depends on the particular photographic element 30 to be processed and prehardening stages e.g., possible development by means of a developing solution containing hardening agents e.g., dialdehyde hardeners as represented by glutaraldehyde or its bisulfite addition product.