JPH08304970A - Processing method of black and white photographic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently fix and clean a monochromatic silver halide photo graphic material while containing high-level silver in a fixing solution tank by maintaining proper image stability while using a minimum quantity of water for cleaning. SOLUTION: In a processing method of a silver halide monochromatic photographic material in a processing device to. move the material processed through a processing tank, (i) A cleaning solution or a stabilizer solution is replenished to a cleaning tank 4 or a stabilizer tank most separated from a fixing solution tank 2, (ii) An effluent is sent to the closest fixing solution tank 2 together with a fixing agent replenishing solution from a cleaning tank 3 or a stabilizer tank closest to the fixing solution tank 2, and a fixing agent acting composition is maintained, (iii) The whole soaking time in a tank having fixing capacity is set not more than 30 seconds, and (iv) The ratio of covering silver in an unprocessed photographic material to the total of an addition rate of the cleaning effluent and the fixing agent replenishing solution to the fixing solution tank 2 is set larger than 10g/l.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to the processing of photographic materials, and more particularly to fixing and cleaning photographic materials.

[0002]

2. Description of the Related Art In recent years, there has been an increasing tendency to reduce the amount of water used for photographic processing for environmental reasons. Water is recognized as a valuable natural resource and efforts are being made to minimize the amount of water used to wash photographic materials. For another reason, some areas are currently taxed on the amount of water used by users of photo processing equipment. Therefore,
Reducing water consumption can benefit users.

Another recent trend in photographic processing is the advent of "plumbless" processing equipment which contains a make-up container and an effluent container within the processor. As a result, no external plumbing, ie plumbing for water supply or drainage, is required on these machines. Instead, the make-up solution and drainage are transferred to and from the machine using suitable containers. In order to minimize the frequency of replacement of the replenisher and drainage containers, it is desirable that the replenishment rate be as low as possible.

Cleaning of the photographic material is necessary to remove any processing chemicals from the processed material that can degrade the image over time. This degradation can be caused by the disappearance of the image, i.e., a decrease in density, or by an increase in density as the coloring material is formed inside the film or paper. Temperature, humidity and light all have strong effects in accelerating their progress. In order to properly preserve the image, it is necessary to keep low levels of residual chemicals in the processed film. In particular, the fixing agent and the by-product of the fixing reaction are known to cause image deterioration when a considerable amount remains in the film.

Stabilizer solutions may also be used in the wash section of the processor instead of water. Stabilizers are usually wetting agents to facilitate washing and drying, fungicides to prevent biological growth in solution or on tank and roller surfaces, additives such as hardeners and / or to delay the aging effect of processed photographic materials. Contains other additives.

In the graphic arts industry, black and white materials (black-and-wh) with very high contrast are used.
ite material) is used. The image is formed only by the developed silver (black) and non-silver (transparent on film, white on paper) areas. Traditionally, the main requirement in the cleaning section of the processor was to keep low levels of fixer (eg ammonium thiosulfate) remaining in the processed film. This is achieved by applying very high wash replenishment rates, and it is not uncommon for graphic arts processing equipment to use 2-10 liters of water per square meter of film to be processed. The residual non-image silver is usually not considered to be the major cause of image degradation, as the fixer replenishment rate is also high. Often, graphic arts processors are equipped with a silver recovery system that separates silver from the fixing solution, whereby the level of silver is kept low, typically about 2 g / l. If the silver level in the fixing bath is so low that high wash replenishment rates can dilute the silver carried to the wash section to a high degree, control of residual non-image silver is not an issue. However, the level of silver in the wash bath will increase if a lower replenishment rate of fixer and wash solution is used, with a tendency to use less wash water these days. This situation is also important for the processing of radiographs and other types of black and white silver halide photographic materials.

The soluble complex of silver and the fixing agent is a by-product of the fixing reaction. These complexes form in the photographic material when the fixing agent reacts with undeveloped silver in the form of silver halide. The complex is formed from the material in the bulk of the fixing solution (bu
lk). In the absence of silver recovery in the fixing bath, especially when a low replenishment rate is applied to the fixer (ie, there is no substantial dilution of the fixing by-product by the addition of replenisher), and the level of silver in the photosensitive material. When is high, the concentration of complexed silver can reach very high levels. Since the fixing speed is inversely proportional to the silver concentration in the fixer bath, the time required to make the film clear also depends on the silver level. While silver recovery is thus beneficial in terms of fixer bath function, it represents a significant and extra capital investment. Ensures the wash section has adequate time to allocate for fixing and washing and also needs to separate both the fixative (typically ammonium thiosulfate or sodium thiosulfate) and the larger soluble silver complex from the film. It has been found that silver recovery is not always necessary, if possible.

A particular problem with graphic arts films is "UV D" due to aging of the processed film.
_The increase in optical density in the UV region of the non-image portion of the spectrum, referred to as the " _min ". Often, UV-contact exposure (ultra-vi) is used to copy graphic arts films onto a printing plate or another film piece.
Olet contact exposure) is used and very high contrast images are needed for accurate reproduction. If the difference between the minimum and maximum optical densities of the reproduced image is reduced by aging, the image contrast will be very low. It may be inaccurate when copying the image. Furthermore, as the minimum density of the image increases, the total exposure time required for the copying process becomes longer. For other types of black and white silver halide images, the tone scale of the image due to aging (tone
Changes in (scale) and contrast are also disadvantageous as they reduce image quality, even without further copying.

It has been empirically known that the effect of non-image residual silver is very poor for image degradation, especially at elevated UV D _min , and greater than that of an equal amount of residual fixer.
After a sufficient time, the colorless silver compound formed as a by-product of the fixing reaction changes to a colored compound such as silver sulfide. Usually the silver complex is present in the fixer and wash solutions in a much lower concentration than the fixer. However, in some circumstances, especially in processors without silver recovery, control of residual silver in the processed film may be more important than control of residual fixer in determining wash water requirements.

Fixing is a two-part process
The first is to make the undeveloped silver in the film a soluble silver salt [ie clearing] and then wash off the soluble salt. In recent years, due to the tendency to shorten the processing time, the fixing time is shortened and the "washing-out" part of the fixing process is "solubilized" in the fixing process.
In some cases, the time allocation is considerably less than the department. If the fixed film did not have enough time to equilibrate with the fixer bath, the washout of the solubilized silver salt would be virtually incomplete, resulting in an unexpectedly large amount of silver being carried to the wash section, which washes away. The demands on the section will increase. Therefore, it is desirable to both maintain low levels of silver in the fixer and to take sufficient time to effectively complete the "wash-off" part of the fixing process.

In normal work in the graphic arts industry, the wash section of the processor is replenished with fresh water from the main source of water and either the overflow from the wash section is drained directly or for further processing before it is drained. To collect. Similarly, in the normal operation of replenishing the fixer bath, the fixer concentrate is mixed outside the processor with direct water from city water at a predetermined ratio to form a fixer replenisher solution of working concentration. The replenishment solution may then be added directly to the fixer replenisher tank of the processor or it may be added to a central storage container for replenishment and piped from there to some processor fixer replenishment systems.

US Pat. No. 5,019,850 [Ishikawa et al.] Describes a photographic processor for color paper which replenishes a bleaching / fixing bath with a mixture of a concentrated processing liquid and a liquid obtained from a washing section. It has been described. In one example,
Bleach-a process of replacing the fixer bath with separate bleaching and fixing followed by three wash baths, pumping some of the wash solution in the first wash bath to the fixer bath with some of the fixer concentrate. The device is described. No mention is made of black and white materials.

US Pat. No. 5,378,588 [Tsuchiya] is similar to the above patent, but uses a solid replenisher rather than a solution. US Patent No. 5,
No. 009983 [Abe] describes a photographic processor for color materials, the claimed device treats and recycles the water obtained from one of the wash tanks. A reverse osmosis system is included. For graphic arts films or radiographic films, the coated silver weight is typically about 3 g / m ² or more, while for color paper the coated silver weight is typically 1 g / m 2. ^It should be noted that it is ² or less. The fixing and washing bath requirements are therefore very different.

[0014]

The problem to be solved by the present invention is suitable for using black and white silver halide photographic materials, such as graphic arts (very high contrast) or radiographic materials, with a minimum amount of water for washing. How to fix and wash efficiently while maintaining good image stability, processing the material in a processor that contains high levels of silver in the fixer tank and does not have a means of silver recovery, for example. .

[0015]

In accordance with the present invention, in a processor for moving material to be processed through a plurality of processing tanks, including at least one tank having fixability and at least one tank which is a wash tank or a stabilizer tank. The method of processing silver halide black and white photographic materials in, i) replenishing the wash or stabilizer solution furthest from the fixer tank with wash solution or stabilizer solution, and ii) closest to the fixer tank Send the outflow from the wash or stabilizer tank to the nearest fixer tank with the fixer replenisher solution to maintain the fixer working composition, iii) Total dipping time in the tank with fixability is 30 seconds And iv) coated silver in unprocessed photographic material (g / m ² ).
Of the washing effluent to the fixing tank and the ratio of the addition of the fixer replenishing solution to the total (l / m ² ) of 10 g / l.
A method characterized by being greater is provided.

[0016]

Surprisingly, in spite of the fact that the wash effluent contains silver which acts to slow the fixing rate, in the present invention an improvement in both fixing and washing functions is achieved at the same time. be able to. The fixing function is
It is improved by reducing the time required to fix the photographic material to the required degree.

Furthermore, the concentrated fixer solution may be used as a replenisher which is diluted by the addition of wash water, so that the volume of fixer solution used is such that the working concentration of replenisher
strength replenisher). The cleaning function is improved by reducing the amount of cleaning water used, shortening the cleaning time, or both.

These improvements are derived from the reduction of silver concentration in the fixer bath. This is because the volume of solution added to the fixer tank per unit area of material to be processed is typically larger than that used in the prior art. As the volume of solution added to the fixer bath for replenishment increases, the concentration of silver in the fixer solution simply decreases for reasons of dilution. This effect in the fixer is an increase in fixing speed.

A further effect of lowering the silver level in the fixer is to reduce the removal of silver from the fixer by the photographic material being processed. This results in a lower concentration of silver in one or more wash baths,
Therefore, the level of silver remaining in the processed film is also reduced. This advantage can be traded for a shorter wash replenishment rate or shorter wash time.

A further benefit of the increased flow through the fixing bath results from the greater dilution of product carried by the developer. Developers also have components that can lead to undesirable stain if not properly washed off.
It is also known that the components of the developer, potassium ions, etc. can suppress the fixing speed. Increased dilution of these ingredients
The fixing speed of the present invention can be substantially improved.

The advantages of the present invention as compared to normal industrial practice can be summarized as follows: i) The time required to properly fix the photographic material is reduced. ii) Capital investment in the fixer silver recovery device is avoided. However, silver recovery can be performed on the used solution to be discarded. iii) The volume of solution needed to replenish both the fixer bath and the wash bath is reduced. iv) The time required for proper washing of the photographic material is reduced. v) Greater dilution of the developer solution in the fixer tank,
Coloring problems are avoided.

[0022]

The preferred method of operation is used to dilute a concentrated fixer replenisher solution which adds to the fixer tank the entire outflow of the cleaner / stabilizer tank closest to the fixer tank. That is. The lower cleaning solution replenishment rate increases the level of contaminants in the cleaning solution overflow. At very low wash solution replenishment rates, high levels of contaminants in the wash solution overflow can significantly change the chemical composition of the resulting fixer replenisher solution from what is intended. For example, comparing the composition of two batches of fixer replenisher with the same concentration, using fresh water for one and highly contaminated cleaning solution drainage for the other, use a highly contaminated cleaning solution overflow. The ionic strength of the fixer at the used concentrations was higher, the fixer and sulfite (sulfite) concentrations were higher, the silver concentration was higher and the pH was different. Changes in pH can adversely affect the fixer's ability to stop continued development when the material is transferred from the development bath to the fixing bath. This results in the formation of dichroic haze, which causes the ultrafine particles of silver in the material to be physically developed, causing an increase in the UV concentration of the material. this is,
Since graphic arts materials are often used as masks in UV contact exposure, there are significant disadvantages in processing such materials. Increasing the fixer concentration can slow the fixing speed slightly if the concentration is different than intended. An increase in silver level reduces the fixing speed. The increase in ionic strength has the effect of swelling the gelatin of the photographic material, which can also reduce the fixing rate. If a rapid fixing is desired, these delay effects can cause a large loss of fixing function, increasing the burden on the cleaning section of the processing equipment,
This results in elevated levels of residual chemicals in the processed photographic material. To counteract these detrimental effects, it is necessary to reformulate the fixer concentrate when using the invention at very low fix and wash replenishment rates.

The preferred silver concentration in at least one of the fixative baths is at least 10 g / l, more preferably at least 15 g / l. The preferred fixer replenishment rate is 125 ml / m ² or less, especially 75 ml, for the material to be processed.
/ m ² or less, especially 65 ml / m ² or less. Detergent / stabilizer replenishment rate is 250 ml / for the material
m ² or less, especially 150 ml / m ² or less, especially 125 m
It is 1 / m ² or less. In the method of the present invention, the fixing time should be short. Fixing times typically depend on the type of material used and the processing equipment, and the time required for proper fixing of the material is that under worst fixing conditions, i.e. silver and other seasoning products in the fixer. It is determined by measuring under a condition where the concentration of other products contained in the state where the fixing operation is possible is high. This situation occurs when the average exposure level of the film is low.

The customary rule of thumb has been used for many years in black-and-white processing, ie the fixing time is twice the clearing time, ie the time for all silver to be solubilized.
A preferred fix time is 80% of the fixer immersion time when the fixer bath is seasoned with substantially unexposed film (so that normal fixer operations are enabled), and It can be defined as the time such that 80% is removed from the non-image parts of the material being processed. This definition removes all the safety margins associated with old rules of thumb and is therefore considered to define an acceptable "short" settling time.

When the processor is operated according to the method of the present invention, ie, all effluent from the wash section is passed through the fixer bath, a valid estimate of the concentration of the fixer bath seasoned with unexposed film is used. You can use a simple expression to provide For the purpose of analysis, the fixer bath and any number of washing baths are treated as a single system, and attention is paid to the volume (volume balance) of the solution entering and leaving the system.
It is also necessary to determine the mass balance of the system by focusing on the mass of silver per unit area of the treated film entering and exiting the system.

Let F be the volume per unit area of the treated film for replenishing the fixer solution added to the fixing bath, and let W be the volume per unit area of the treated film of the wash solution taken from the first wash bath and added to the fixer bath. Let A be the coating weight per unit area of silver in the film (assuming all silver is solubilized in the fixer bath), δ is the film carried out of the last wash bath and the last fixer bath. Volume difference per unit area (taking into account small changes in gelatin expansion),
where a is the residual silver retained in the film after it exits the last wash bath, and C _fmax is the maximum silver concentration in the first fixing bath (ie, fixer effluent concentration), C _fmax = It can be written as (A−a) / (W + F + δ).

From the settings, a is typically 50 mg / m ² or less, and for most black and white photographic film products, A is typically 2.5 g / m ² or more, so a can be ignored. δ
The value of is typically about 5 ml / m ² for photographic materials coated with gelatin on both sides, while W + F is almost always 100.
ml / m ^{2 and} above, and probably 150 ml / m ^{2 and} above. Therefore, even if δ is ignored, a good evaluation value of the maximum silver concentration of the fixing solution can be obtained, which is approximately 5% or less, and almost certainly 10% or less. Rewriting the above equation into a very useful and simple form gives C _{fmax ≈A} / (W + F).

In the attached drawings, FIG. 1 shows a developer tank (1),
1 shows a conventional processor containing a fixer tank (2) and two wash tanks (3 and 4). Developer tank (1)
The holding tank (5) receiving the replenishment contains a developer replenishing solution having a working concentration that has been mixed in advance, and this is pumped to the developer tank at an appropriate flow rate using the pump (10). The fixer tank (2) is replenished by the pump (11), and the fixer concentrate is sent from the holding container (26) to the fixer tank (2) at an appropriate flow rate. The wash tanks (3) and (4) send an overflow to the wash tank (3) when a new wash solution is pumped from the holding tank (15) to the wash tank (4) by the pump (16). And arranged so that a conventional countercurrent wash section is formed. The overflow (25) from the washing tank is discharged from the processor in the same manner as the fixer overflow (14) and the developer overflow (13).

FIG. 2 illustrates one embodiment of the present invention. The processor comprises a developer tank (1), a fixer tank (2) and two wash tanks (3 and 4). The holding tank (5), to which the developer tank (1) is replenished, has a pre-mixed developer replenisher of the working concentration,
This is pumped to the developer tank using the pump (10) at an appropriate flow rate. The fixer tank (2) is replenished by pumps (11) and (12), which supply the fixer replenisher of the working concentration to the fixer tank (2) from the holding container (6) at appropriate flow rates. Send and wash water from the wash tank (3). Pump (1
The replenishment rate of the solution supplied by 1) and the pump (12) is maintained at a predetermined rate. The washing tanks (3) and (4) are supplied with fresh washing solution from the holding tank (15) by the pump (16) by the washing tank (4).
Arranged so that the resulting overflow, when pumped into the washing tank (3), forms a conventional countercurrent washing section. The level sensor (9) detects when the level of the cleaning solution in the cleaning tank (3) falls below a certain level. The signal emitted by the level sensor control means (7) sends a signal to the pump (16) which adds fresh wash solution to the wash tank (4). When the level in the wash tank (3) rises above a certain level due to overflow from the wash tank (4), the level sensor controller stops the flow of fresh wash liquid to the wash tank (4). Also, an additional level sensor (not shown) may be provided to control evaporation loss and any suitable additional solution replenishment may be made to any tank.

FIG. 3 shows two fixer tanks (21 and 2).
2) and the same as described in FIG. 2 except that only one wash tank (23) is provided. In the fixer tank, the replenishing solution is pumped to the fixer tank (22) and the overflow caused thereby is caused by the fixer tank (2).
It is designed to go into 1). The wash tank (23) is provided with a reservoir (17) from which the wash solution is pumped (1
6) and the pump (16) continuously pumps the solution from the sump (17) to the wash tank (23). The overflow from the wash tank (23) descends the pipe (20) and returns to the sump. Float valve (2
4) senses the level in the reservoir. When the level drops until the valve (18) opens, fresh water is the main source (19)
From the pump to the sump under pressure. If the level is high enough,
The float valve (24) shuts off the supply. Fixer replenishment can be accomplished by either pumping the cleaning solution from the reservoir (17) (not shown) or directly from the cleaning tank (not shown).
Achieved by pumping to the fixer tank (22) with 2). At the same time as operating the pump (12),
The pump (11) takes out the fixer concentrate from the holding container (6) and compares it with the ratio supplied by the pump (12) at a predetermined ratio to the fixer tank (2).
Supply to 2). Also, an additional level sensor (not shown) may be provided to control evaporation loss and any suitable additional solution replenishment may be made to any tank.

FIG. 4 illustrates another aspect of the present invention. The processor contains a single developer tank (1) and a fixer tank (2)
And two wash tanks (3 and 4) are provided. The wash water pump (16) and the fixer concentrate pump (11) are operated simultaneously to operate the tanks (15) and (6).
To deliver the solution at a predetermined volume ratio. The operation of the pump (16) replenishing the washing tank (4) causes a cascade overflow to the fixer tank (2). Also, an additional level sensor (not shown) may be provided to control evaporation loss and any suitable additional solution replenishment may be made to any tank.

FIG. 5 is a graph showing the silver carried out of the fixing solution by the photographic material as a function of immersion time in the fixing solution. The plotted values are obtained from the following examples provided for a better understanding of the invention. Black and white photographic materials are known, especially high contrast art and radiographic materials for graphic arts. The weight of these silver skin covers ranges from 1 to 15 g / m ² ,
Typically 2-8 g / m ² , most typically 2.5-6 g
/ m ² . The following examples are provided for a better understanding of the invention.

[0033]

EXAMPLES Experiments were conducted to demonstrate the advantages of the present invention.
As a control (case A), the graphic arts film was processed using the conventional processor shown in FIG. 1 having a developer tank, a fixer tank and two wash tanks. The wash water overflow was collected for processing and was not used to dilute the fixer. No silver recovery system was used to separate the silver from the fixer. The coated silver weight of the film was 3.3 g / m ² and the halide ratio was 70% chloride to 30% bromide. The exposure dose was about 2% area (since the silver level in the fixer was very high, 98% of the coated silver resulted in no image and therefore no fixing was necessary) Replenishment rate is 125 ml / m ² and fixer replenishment rate is also 125 m
It was 1 / m ² . The fixer replenisher was prepared from a concentrate (formulation A shown in Table 1 below) and diluted with 2 parts by volume of water to 1 part by volume of concentrate. Both developing and fixing time is 3
It was 25 seconds at 5 ° C, and the cleaning time was 30 seconds in total at 20 ° C. The ratio of in-air time and inundation time is 1: 4
Therefore, the fixing time of 25 seconds corresponds to the fixing solution immersion time of 20 seconds in the processing apparatus used in this experiment. Several hundred square meters of film were processed to fully season the fixing and wash baths.

Several unexposed pieces of the same film were
It was then processed for various processing times of 15 to 40 seconds so that the development and fixing times were equal in each case. (Processing time includes the time required to move through the air between processing tanks. Therefore, for example, the development time is fixed when the leading edge of the film piece just touches the developing solution in the developing solution tank. It is defined as the time until the solution in the tank is just touched. This processing time range corresponds to the fixing solution immersion (dipping) time range of 12 seconds to 32 seconds.) The wet film sample was not washed. , Exiting the processor after passing through the last set of nip rollers at the exit of the fixing bath. After the samples were dried in air, the amount of silver remaining in each sample was measured by X-ray fluorescence at mg / m ² .

[0035]

Table 1 About 1 liter concentrate formulation Ingredients Ingredient A (g) Ingredient B (g) Acetate 48 30 Ammonium acetate 90.9 68 Ammonium thiosulfate 535 500 Ammonium sulfite 48 40 Water-deionized 521 606

The processor was then modified to allow the invention to be implemented in the form shown in FIG. 2 (Case B). The processing and exposure conditions were unchanged except that the reconstituted fixer concentrate (formulation B shown in Table 1 above) was used to directly replenish the fixer tank at a replenishment rate of 62 ml / m ² . The cleaning replenishment rate remained at 125 ml / m ² . Once a few hundred square meters of the same film were processed as before and once the solution had been thoroughly seasoned, another test of silver retention in the film for fixer immersion time was performed. The results of the test in both cases are shown in FIG. 5 in which the residual silver is plotted against the fixer immersion time. Residual silver in the film dropped rapidly as the fixer immersion time increased from 12 seconds. With conventional replenishment (Case A), most of the "washing-out" part of the fusing process is not completed until about 19 seconds. When using wash water from the wash tank (case B), this point occurs 3-4 seconds earlier. At 20 seconds, there is about 24% less silver in Case B treated film than Case A. However, at 16 seconds, Case B has about 69% less silver. Therefore, at the end of the case A experiment, the fixer silver level was 21 g / l, while at the end of the case B experiment, the fixer silver level was 1.
The invention (Case B) provides a very significant benefit at shorter fixing times than would be expected from a simple consideration of the fixer silver concentration in the two cases of 8.5 g / l. The fixer silver level for Case B was 88% of that for Case A.

The reason this technique yields more than expected benefits is that in Case B, once the majority of the "wash-off" portion of the fixer is complete and the film is in equilibrium with the fixer solution for a longer period of time: It has about 4 seconds. In case A, it takes only about 1 second. Therefore,
In Case B more silver is removed from the film. The extra time for equilibration is that the fixing speed is inversely proportional to the silver concentration of the fixer, and in case B the silver concentration of the fixer is case A.
Due to the fact that fixing proceeds faster in Case B, since it is lower. It is the additional dilution effect that induces the drop in fixer silver levels in Case B. Case B
In the absence of additional dilution by the fixer with a larger solution flow at, the presence of silver in the wash solution used to dilute the fixer concentrate would increase the fixer silver level compared to Case A. .

In case B, since less silver is carried into the washing section, the burden of washing off the film is less. At the end of the case A experiment, the amount of silver remaining on the film after the whole process, ie after development, fixing, washing and drying was 11 mg / m ² , whereas at the end of the case B experiment 8 mg of silver remained. It was / m ² . Considering the effect of the present invention on the fixing time, in case A, silver of 8
0% separated in about 19 seconds. Using the proposed short fix time definition, 19 seconds is approximately 80% of 24 seconds.
In the examples, the immersion time of the fixing solution is 20 seconds, which is shorter than 24 seconds, which is an example of the step of "short" fixing time.

In summary, the above shows that the application of the present invention 1) increased the fixing speed, 2) reduced the volume of fixer replenisher used per unit area of the film being processed, and 3) improved the cleaning function. Obviously, improved cleaning functionality can be traded for shorter cleaning times and / or lower cleaning replenishment rates. However, it should be noted that sufficient cleaning of the fixer in the wash bath was not achieved and such low washout that residual fixer in the treated material was a determinant of image stability on aging (over time). Replenishment rate should not be used.

It is also clear that increasing the temperature of the fixing bath increases the fixing speed. This is generally undesirable because it causes increased evaporation from the fixer bath, causing problems of deposit of fixer on the rollers and of the fixer from the tank wall to the adjacent tank (creep). Furthermore, the energy required to heat the solution increases and the preheating time also increases. Most graphic arts processors have 35
It operates at a fusing temperature of ° C, which is well above ambient in most parts of the world. It is known to use a fixing temperature of 38 ° C. in radiographic processors.

In the present invention, the fixing time is shortened in consideration of the maximum predicted silver concentration so that the maximum profit can be obtained. The fixing solution immersion time considered is 30 seconds or less. Greater benefits are obtained with flood times of 25 seconds or less and maximum benefits are obtained with flood times of 20 seconds or less. The highest predicted silver concentration considered is preferably 10 g / l or higher, most preferably 15 g / l or higher.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of the present invention.

FIG. 2 illustrates an aspect of the present invention.

FIG. 3 illustrates an aspect of the invention.

FIG. 4 illustrates an aspect of the invention.

FIG. 5 is a graph showing the results of the above examples.

[Explanation of symbols]

1 ... Developer tank, 2 ... Fixer tank, 3 ... Wash tank, 4 ... Wash tank, 5, 6 ... Holding tank,
7 ... Level sensor control means, 9 ... Level sensor, 1
0, 11, 12 ... Pump, 13 ... Developer overflow, 14 ... Fixer overflow, 15 ... Holding tank, 16 ... Pump, 17 ... Reservoir, 20 ... Pipe,
21, 22 ... Fixer tank, 23 ... Cleaning tank, 24 ...
Float valve, 25 ... Overflow, 26 ... Holding container.

Front Page Continuation (72) Inventor Paul Wagner, 16337 Church Street, Holly, New York, 14470, United States (72) Inventor Andrew Michael Weiner, 14718 Highland Avenue, Rochester, New York, United States 14618

Claims (2)

[Claims] 1. A method of processing a silver halide black and white photographic material in a processor for transferring material to be processed through a plurality of processing tanks including at least one tank having fixing ability and at least one wash tank or stabilizing tank. , I) replenishing the wash or stabilizing tank furthest from the fixing tank with wash or stabilizer solution, and ii) fixing the effluent from the washing or stabilizing tank closest to the fixing tank to the closest fixing Iii) The total immersion time in the tank having the fixing ability is less than 30 seconds to maintain the composition of the fixing solution used by passing it through the tank together with the fixing solution replenishing solution, and iv) the silver (g / m ²⁾ of a percentage of the total (l / m ²⁾ in the proportion of addition of the wash effluent and fixer replenisher to the fixing tank and characterized in that 10 g / l or more How. 2. The method according to claim 1, wherein no silver compound is taken out of the processing solution in the fixing tank except for overflow or removal by photographic material to be processed.