JPH027451B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for cleaning photographic processing equipment, and more particularly to a method for effectively removing contaminants whose main component is silver sulfide. Photographic processing includes steps such as development, stopping, bleaching, bleach-fixing, fixing, prewashing, washing, and stabilization. The photographic processing equipment used in these photographic processing includes developing machines such as a flat plate or roll conveying type developing machine, a cine type long developing machine, a hanger type short developing machine, a silver recovery device, a waste liquid processing device, and the like. It is common for these photographic processing equipment to become contaminated after prolonged use, and such contamination is caused by oxides of developing agents,
Silver halide is eluted by the large amount of sulfite contained in the black and white developer, and black silver oxide is generated during development, as well as gelatin in sensitive materials, additives, and thiosulfate, which is usually used as a fixing agent for silver halide. salt,
The main cause is silver sulfide, which is generated by the decomposition of silver thiosulfate complexes. These contaminants are not only visually undesirable, but also adhere to the tanks of photographic processing equipment, the inner walls of circulation system piping, conveyance rollers, etc. This can cause problems such as clogging. Techniques for removing these contaminants include techniques using sulfuric acid solutions of potassium dichromate or potassium permanganate, and PH1 containing ceric compounds.
The following techniques using an aqueous solution (JP-A-50-23229), a technique using an acidic aqueous solution containing a persulfate and an organic quaternary amine compound (JP-A-52-42727), etc. are known. However, in these technologies, potassium dichromate and potassium permanganate are not preferred from the viewpoint of pollution, and furthermore, ceric compounds, persulfates, and organic quaternary amine compounds are harmful to developing agent oxides and silver oxides. The removal effect is great for silver sulfide, but the reality is that the removal effect is small or almost non-existent for contaminants whose main component is silver sulfide. The first object of the present invention is to provide a method for cleaning contaminants adhering to photographic processing equipment containing silver sulfide as a main component. A second object of the present invention is to provide a method for recovering silver from contaminants whose main component is silver sulfide. Furthermore, a third object of the present invention is to provide a cleaning method that causes less pollution. As a result of various studies, the present inventors have discovered that the above object can be achieved by cleaning photographic processing equipment using an acidic aqueous solution containing an iodine compound and/or a bromine compound. The iodine compounds used in the present invention include hypoiodites, iodates, periodates, iodides, etc., and preferably those that release iodine ions in an aqueous solution, specifically sodium iodide, iodine, etc. Examples include ammonium chloride, potassium iodide, and the like. The amount of iodine compound added to the cleaning solution is very preferably 0.5 mol or more per unit, and in this case, the cleaning solution has a very strong effect of dissolving silver sulfide.
However, even in cleaning solutions containing 0.005 mol or more and less than 0.5 mol of iodine compounds per unit, silver sulfide can be decomposed into substances that easily dissolve in fixing solutions containing commonly known thiosulfates, etc., in a short period of time. occurs, and iodine compounds per 1
A similar effect can be obtained with a cleaning solution having a concentration of less than 0.005 mol if the time is extended. Therefore, even if the concentration of the iodine compound is low, by immersing it in the cleaning solution and then in the fixing solution, contaminants mainly composed of silver sulfide can be completely removed, and silver can be recovered in the fixing solution. Further, the bromine compounds used in the present invention include hypobromite, bromate, bromide, etc., and preferably those that release bromine ions in an aqueous solution, specifically sodium bromide, ammonium bromide, Examples include potassium bromide. The amount of bromine compound added to the cleaning solution must be at least 1 mole per bromine compound in order to have the effect of dissolving silver sulfide. In addition, if the bromine compound is less than 1 mole per 1 mole, it has no effect of decomposing silver sulfide such as an iodine compound and converting it into a substance that easily dissolves in fixing solutions containing commonly known thiosulfates and the like. Further, the iodine compound and the bromine compound used in the present invention may be used alone or in combination. In order to make the cleaning solution of the present invention an acidic aqueous solution, hydrochloric acid, sulfuric acid, sulfamic acid, phosphoric acid, chloric acid,
Inorganic acids such as iodic acid, bromic acid, nitric acid, and boric acid are preferably used, but acetic acid, citric acid, oxalic acid,
Organic acids such as phthalic acid can also be used. PH is
Must be below 4.5, preferably PH
2 or less, and a pH of 1 or less gives even better results. When the iodine compound of the present invention is at a low concentration, the fixing solution used after immersion in the cleaning solution is a general fixing solution containing thiosulfate, thiocyanate, etc. as a main component, which is used for general color and black and white films, and photographic paper. A fixer and a bleach-fixer can be used. Furthermore, by adding an alkaline agent such as potassium hydroxide or sodium hydroxide to neutralize the pH of the cleaning solution of the present invention containing a certain amount of silver sulfide and adding it to the fixing solution, silver can be recovered as a normal fixing solution. can. The photographic processing equipment to which the method of the present invention can be applied includes equipment used in development processing and its accessories, processing solution regeneration equipment, silver recovery equipment, wastewater treatment equipment, etc., such as fixing solutions, bleach-fixing solutions, and subsequent water washing. It is highly effective for equipment that is contaminated with silver sulfide as a main component due to contact with liquids containing silver thiosulfate complexes such as water. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 Sakura color paper (roll form) (Konishi Roku Photo Industry Co., Ltd.) was photoprinted and then subjected to continuous replenishment processing (referred to as running processing) using an automatic processor (RP-1180 processor manufactured by Noritsu Koki Co., Ltd.). [Processing process]

[Color development tank liquid]

Benzyl alcohol 15ml Triethanolamine 15ml Potassium sulfite 2.0g Potassium bromide 0.7g Sodium chloride 0.2g Potassium carbonate 30.0g Hydroxylamine sulfate 3g 1-Hydroxy-ethylidene-1,1 diphosphonic acid 0.6g Magnesium chloride hexahydrate 0.3g Hydroxy Ethyliminodiacetic acid 2.5g 3-methyl-4-amino-N-ethyl-N-
(β-Methanesulfonamidoethyl) aniline sulfate 5.5g Fluorescent brightener (4,4'-diaminostilbendisulfonic acid derivative 1.0g Potassium hydroxide 2.0g Add water to make 1. [Color development replenisher] Benzyl alcohol 20ml Triethanolamine 20ml Potassium sulfite 3.0g Potassium carbonate 30.0g Hydroxylamine sulfate 4.0g 1-Hydroxy-ethylidene-1,1-diphosphonic acid 0.6g Magnesium chloride hexahydrate 0.3g Hydroxyethyliminodiacetic acid 2.5g 3 -Methyl-4-amino-N-ethyl-N-
(β-Methanesulfonamidoethyl) aniline sulfate 7.0g Fluorescent brightener (4,4'-diaminostilbendisulfonic acid derivative) 1.5g Potassium hydroxide 8.0g Add water to bring the total amount to 1. [Bleach-fix tank solution] Ferrous ammonium ethylenediaminetetraacetic acid dihydrate 60g Ethylenediaminetetraacetic acid 3g Ammonium thiosulfate (70% solution)
100ml ammonium sulfite (40% solution) 27.5ml Adjust pH to 7.10 with potassium carbonate or glacial acetic acid Add water to bring the total volume to 1. [Bleach-fixing replenisher A] Ethylenediaminetetraacetate ferrous ammonium dihydrate 260g Potassium carbonate 42g Add water to bring the total amount to 1. The pH of this solution is 6.70±0.1. [Bleach-fix replenisher B] Ammonium thiosulfate (70% solution) 500ml Ammonium sulfite (40% solution) 250ml Ethylenediaminetetraacetic acid 17g Glacial acetic acid 85ml Add water to bring the total volume to 1. The pH of this solution is 4.60±0.1. Fill an automatic processor with the above color developer tank solution, bleach-fix tank solution and water (in the pre-wash tank), and add the above color developer replenisher and bleach-fix replenisher A, every 3 minutes while processing the color paper. A running test was conducted while replenishing B and pre-rinsing water through a metering cup. The amount of replenishment to the color development tank is per ^1m2 of color paper.
The amount of replenishment to the bleach-fixing tank was 25 ml each for bleach-fixing replenishers A and B. Washing water was replenished at 10 ml per 1 m ² of color paper by continuously adjusting the flow rate with a flow meter to match the amount of processing. (Experiment) Take the overflow of washing water from the point where convergence is reached (Note 1) after the above continuous treatment, put it in a 250ml narrow-mouth bottle, and leave it at 33°C for 3 weeks. Contaminants were generated. This narrow-mouthed bottle was washed with water to serve as a contaminated sample, and the washing liquid shown in Table 1 below was poured into it and left at room temperature.The results of observation are shown in Table 2. Furthermore, what is attached to the 250ml narrow neck bottle is a blackish-brown silver mirror-like contaminant, and its main component is silver sulfide. (Note 1) Amount of bleach-fix solution refilled to the bleach-fix bath (replenisher A+
Convergence was reached when the total amount of replenisher B+the amount of color developing solution that adhered to the photosensitive material) became twice the tank capacity.

【table】

【table】

[Table] As is clear from Table 2, the cleaning solution No. 1, an acidic aqueous solution containing potassium persulfate and a quaternary salt, has almost no effect, and even the cleaning solution No. 2, ceric sulfate, is not perfect and is not suitable for practical use. I can't offer it. In comparison, it can be seen that the method of the present invention using an acidic aqueous solution containing an iodine compound and an acidic aqueous solution containing a bromine compound can completely remove contaminants and is very effective. Also, with cleaning solutions No. 4 and No. 5, make a large amount of a pale yellow contaminant that is thought to be silver iodide, and dissolve it in a solution diluted to 1/2 of the same bleach-fix replenisher B.
Electrolytic silver recovery equipment is installed at the place where the silver concentration reaches 5g/
Silver could be recovered using BF-50 (manufactured by Sun Seiki Co., Ltd.). Example 2 As in Example 1, a 250ml narrow-mouth bottle with contaminants mainly composed of silver sulfide was used as a sample. 20 g of ammonium iodide, 10 g of glacial acetic acid per 1
g, and adjust the pH to 0.5 with sodium hydroxide and sulfuric acid.
Adjustments were made to 1.5, 3.0, 5.0, and 7.5, and the samples were placed in a narrow-mouth bottle and observed. The results are shown in Table 3.

[Table] As can be seen from Table 3 above, the lower the pH of the cleaning solution containing the iodine compound of the present invention, the better. Also, as a bromine compound, ammonium bromide is
I tried changing the PH of the cleaning solution containing 300g per bottle, but the lower the PH, the better it was, and the pH was 4.5.
The cleaning effect was extremely weak above this point. Example 3 In the continuous processing of Example-1, a small amount of processing of 3 m ² of color paper per day was continued for two weeks.
The roller with contaminants adhering to it from the second washing tank was taken out and immersed in the washing liquid shown in Table 1. As a result, the comparison cleaning solution and the cleaning solution of the present invention are shown in Table-2.
The results were the same as those shown in Figure 2, indicating that the method of the present invention had an extremely excellent cleaning effect and was very effective.

Claims (1)

[Claims] 1. A method for cleaning photographic processing equipment, which comprises cleaning the photographic processing equipment using an acidic aqueous solution containing an iodine compound and/or a bromine compound.