JPH04296846A - Direct positive type silver halide photosensitive material - Google Patents

Abstract

PURPOSE:To provide a direct positive type silver halide photosensitive material in which generation of process unevenness, a process scar, a roller mark and the like is suppressed, linearity is excellent, and reproducibility from an original image is superior, in a rapid developing process with an automatic developing machine. CONSTITUTION:In a constitution layer of a direct positive type silver halide photosensitive material fogged beforehand, the direct positive type silver halide photosensitive material wherein a protective layer film thickness on an emulsion layer is 1.1 to 3.0mum, a film thickness ratio of the protective layer to the emulsion layer is 0.5 or more, a total film thickness of these layers is 5mum or less, a mat agent of an average particle diameter 4mum or less is contained in the protective layer, and a total photographic processing time is 60 seconds or less, or this photosensitive material containing a latex particle composed of hydropholic high polymer in the emulsion layer forms the constitution.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a direct positive type silver halide photographic light-sensitive material which has been fogged in advance, and more particularly, to
The present invention relates to a direct positive type silver halide photographic light-sensitive material with high sensitivity that does not cause processing unevenness, roller marks, pick-offs (slight scratches on the film surface during processing), etc. during rapid automatic processing in seconds or less.

0002

Background of the Invention Usually, when a silver halide photographic light-sensitive material is exposed and developed using a light source in the wavelength range to which the light-sensitive material is sensitive,
The degree of blackening increases as the exposure dose increases, reaching a maximum value at a certain exposure dose, but when the exposure dose is further increased, the blackening density decreases, and this phenomenon is called solarization. There is. Therefore, if the silver halide emulsion is optically or chemically given an appropriate fog so that the blackening density reaches its maximum value, solarization will occur upon exposure and a positive image will be directly formed. A light-sensitive material that utilizes such a reversal phenomenon is called a direct positive silver halide photographic light-sensitive material.

Direct positive silver halide photographic materials are
It is used for the reproduction of various types of photographs, and medical X-ray photographs in particular have a retention period stipulated by law for photographs (original images) used for diagnosis. , reproduction photographs that are faithful to the original paintings are essential for treatment and other purposes.

Furthermore, the spread of diagnostic imaging modalities such as X-ray CT (computed tomography), MRI (magnetic resonance imaging), and CR (computed radiography) has led to the dualization of diagnosis and treatment. This is accelerating the reproduction of diagnostic images.

Furthermore, the spread of these image diagnostics has led to an increase in the throughput of photosensitive materials, leading to the spread of ultra-quick processing of 60 seconds or less. As a result, the thickness of the conventional emulsion layer and protective layer,
Alternatively, it has become impossible to deal with the problem with film strength, and it has become necessary to impart rapid processing characteristics to direct positive photosensitive materials. Generally, to impart rapid processing suitability to a silver halide light-sensitive material, the amount of silver halide is reduced, but this method requires a technique that does not involve a decrease in sensitivity and maximum density. As a method for saving silver without reducing sensitivity, for example, US Pat. No. 2,966,382 or US Pat. No. 2,178,38
No. 2 is known, and this technology achieves high sensitivity, high contrast, and It is said that a silver halide photographic material with high covering power can be obtained. However, when these light-sensitive materials are processed ultra-quickly using an automatic processor with a total processing time (including transition parts) of 60 seconds or less, the lowest density (fogging) occurs.
It has high graininess, poor graininess, and inevitably causes processing unevenness such as roller marks and processing scratches (pickoffs) on the surface of the photosensitive material.

[0006] As a means of improving the minimum density (fog), it is known to add various additives to the emulsion or developer, but all of them cause reductions in sensitivity, contrast, and maximum density, and are therefore undesirable. do not have. Furthermore, as a means to improve graininess, for example, increasing the amount of binder is known, but this also has the drawback of causing a decrease in sensitivity, gamma, or maximum density.

On the other hand, there is a strong demand for reproduction films to faithfully reproduce the images of the original film. Therefore, a photosensitive material with a characteristic curve having a gamma of around 1.0, excellent linearity, and good physical properties must be obtained by ultra-quick processing in 60 seconds or less using an automatic processor.

[0008]

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to faithfully reproduce original film images through ultra-quick processing in less than 60 seconds, and to produce high-sensitivity direct positive images without processing unevenness such as roller marks or pick-offs (processing scratches). An object of the present invention is to provide a type silver halide photographic light-sensitive material.

[0009]

SUMMARY OF THE INVENTION It has been found that the above objects are achieved by the present invention as described below. That is, (1) in the constituent layers of the direct positive silver halide photographic material which have been fogged in advance, the thickness of the protective layer on the emulsion layer is 1.1 μm to 3.0 μm;
The thickness ratio of the protective layer and the emulsion layer is 0.5 or more, the total thickness of the emulsion layer and the protective layer is 5 μm or less, and the protective layer contains a matte having an average grain size of 4 μm or less. 1. A direct positive type silver halide photographic light-sensitive material, which contains a silver halide agent and has a total photographic processing time of 60 seconds or less. Alternatively, (2) this can be achieved by the direct positive silver halide photographic light-sensitive material described in item (1) above, which contains latex grains made of a hydrophobic polymer in the emulsion layer. The present invention will be explained in detail below.

In the present invention, the matting agent having an average particle diameter of 4.0 μm or less used in the protective layer on the emulsion layer may be an inorganic or organic matting agent, with polymer matting agents being particularly preferred.

Preferred examples of the polymer matting agent used in the present invention include water-dispersible vinyl polymers such as polymethyl methacrylate, cellulose acetate propionate, and starch. In particular, spherical matting agents of water-dispersible vinyl polymers such as homopolymers of acrylic esters such as methyl methacrylate, glycidyl acrylate, and glycidyl methacrylate, composites of these acrylic esters, or copolymers with other vinyl monomers. is preferred.

As the inorganic matting agent, for example, silver halide, barium strontium sulfate, calcium carbonate, silicon dioxide, magnesium oxide, titanium oxide, etc. are preferably used. For more information see British Patent No. 1,055,7
No. 13, U.S. Patent No. 1,939,213, U.S. Patent No. 2,992
, No. 101, No. 3,767,448, West German Patent No. 2,5
No. 29,321, British Patent No. 760,775, 1 and 2
60,772, U.S. Patent No. 1,201,905, U.S. Patent No. 2,192,241, U.S. Patent No. 3,053,662, U.S. Patent No. 3
Inorganic matting agents such as those described in , No. 769,020, No. 4,029,504, etc. can be preferably used. The particle size of the matting agent used in the present invention is preferably 4 μm or less, and these measurements can usually be performed using a Coulter counter or directly using an electron microscope. If any of the particles is not spherical, its projected area is transformed into a circle, and the diameter at that time is defined as the particle size.

[0013] The above-mentioned average particle size used in the present invention is 4 μm.
The following matting agents are added into the protective layer on the direct positive silver halide emulsion layer according to the invention. Addition amount is protective layer m
The amount may be 5 mg to 500 mg per 2, more preferably 2
It is 0 mg to 300 mg. It may be added at any appropriate time from the time of preparation of the protective layer coating solution to the time of coating.

Next, the latex particles according to the present invention will be explained. The latex used in the present invention is a hydrophobic polymer particle, such as styrene, styrene derivatives, alkyl acrylates, alkylmethalylates, olefin derivatives, halogenated ethylene derivatives, acrylamide derivatives, methacrylamide derivatives, vinyl ester derivatives, acrylonitrile, etc. Obtained by polymerizing monomers arbitrarily selected from among them. In particular, the content of styrene derivatives, alkyl acrylates, and alkyl methacrylates is at least 30 mol% or more, preferably 50 mol% or more. Hydrophobic polymers are made into latex by emulsion polymerization. Emulsion polymerization can be carried out by dissolving a solid polymer in a low boiling point solvent, finely dispersing it, and then distilling off the solvent, but emulsion polymerization is preferable in terms of making the particle size fine and uniform. As the surfactant used during emulsion polymerization, it is preferable to use an anionic or nonionic surfactant, and the amount used is 10% based on the monomer.
It is preferably less than % by weight. The molecular weight of the hydrophobic polymer is 30
00 or more, and there is almost no difference in transparency depending on the molecular weight.

The above-mentioned latex grains used in the present invention are added to the direct positive silver halide emulsion layer according to the present invention. The amount added is 10 mg to 100 per m2 of emulsion layer.
It may be 0 mg, more preferably 50 mg to 500 mg. The addition may be made at any appropriate time from the time of preparation of the emulsion coating solution to the time of coating. Next, the latex according to the present invention (
Although specific examples of hydrophobic polymer particles are shown below, the present invention is not limited to these compounds.

[0016]

[Chemical formula 1]

[0017]

[Case 2]

[0018]

[Chemical 3]

The above-mentioned latex (hydrophobic polymer particles) according to the present invention can be prepared by known methods such as JP-A-61-2847.
It is synthesized by the method described in No. 55 or a method similar thereto.

As the silver halide emulsion for obtaining the characteristic curve of the present invention, any conventionally developed emulsion may be used.

That is, the silver halide emulsion used in the present invention may be produced by any of the neutral method, acid method, and ammonia method. Further, mixed methods such as a single jet method, a double jet method, and a controlled double jet method can be used, but a controlled double jet method in which particles are grown while controlling pH, pAg, etc. is particularly preferred.

When core/shell type emulsion grains are used, the silver halide composition may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, and silver chloroiodobromide. Silver chloride, silver chlorobromide, silver bromide, silver chloroiodobromide are preferred, particularly 0
Silver chlorobromide containing ~80 mole % silver bromide is preferred. or,
Silver halide grains may be monodisperse or polydisperse.

The silver halide composition of the shell may be of any type as long as it has a smaller solubility product than the silver halide of the core, but silver bromide or silver iodobromide is preferred.

(In the case of silver iodobromide, the silver iodide content is preferably 6 mol % or less.) The ratio of shell to core is 1:100 to 10:1, preferably 1:1 as a molar ratio.
The ratio is 10 to 5:1.

The crystal phase after shell formation is cubic, 14
It may be a hedral, octahedral, or other irregular crystal shape, and the particle size is 0.1 to 2.0 μm, preferably 0.15 to 2.0 μm.
It is 1.0 μm.

Further, in the present invention, an appropriate electron trap can be used in order to obtain a good positive image. This is effective in preventing reactions in which silver nuclei form and grow between photoelectrons and silver ions. As specific means, noble metal atoms or the like may be introduced as an inorganic desensitizer into the crystal interior of the silver halide grains, or an electron-capture desensitizing dye that is adsorbed on the crystal surface may be used.

When an inorganic desensitizer is used, a soluble group VIII metal salt such as a soluble rhodium salt or a soluble iridium salt may be added to incorporate the inorganic desensitizer into the silver halide grains. . These soluble salts are preferably added in an amount of 10-8 to 10-2 mol, more preferably 10-5 to 10-3 mol, per mol of silver halide, and this is added to the emulsion as an aqueous solution during the preparation of silver halide grains. It is desirable to add it inside.

Regarding the technique of using an electron capture type desensitizing dye, see British Patent Nos. 1,186,717 and 1,1.
No. 86,714, No. 1,186,716, No. 1,
No. 520,817, U.S. Pat. No. 3,501,306,
No. 3,501,307, No. 3,501,310,
It is described in No. 3,531,288, etc. A suitable fog is imparted to the silver halide emulsion used in the present invention, and for this purpose a reducing agent and a gold compound are used for the silver halide emulsion. After being coated with at least one compound selected from thiosulfate and/or thiocyanate, or by coating with a reducing agent and a gold compound, thiosulfate and/or thiocyanate is formed. Even better fogging can be imparted by containing at least one or more selected compounds. In the present invention, fogging is imparted by the above method, but good "bleeding" can be obtained by adding water-soluble iodide to the silver halide emulsion before fogging is imparted. Examples of water-soluble iodides include ammonium, potassium, lithium, and sodium iodides, and the amount added is 1 to 10 mmol of water-soluble iodide per mol of silver halide. If the amount added is less than this, the removal will be poor. If the amount is more than this, a sufficient maximum concentration cannot be obtained and the concentration decreases during storage.

The conditions for fogging the silver halide can be varied over a wide range, but the pH is generally in the range of 5.5 to 9, preferably 6 to 7. Also, pAg is generally within the range of 6.5 to 8.5, and the temperature is generally 40°C.
The temperature range is from 100°C to 100°C, preferably from 50°C to 70°C.

A hydrophilic protective colloid such as gelatin, which suspends the silver halide grains during fogging, is preferably used in an amount of 30 to 200 g per mole of silver halide.

Reducing agents used in the present invention include aldehyde compounds such as formalin, hydrazine, triethylenetetramine, thiourea dioxide, imino-amino-
Organic reducing agents such as organic amine compounds such as methanesulfinic acid, inorganic reducing agents such as stannous chloride, or reducing agents such as amine borane are preferably used.

The concentration of the reducing agent used varies depending on the silver halide grains, application purpose, etc., and also varies depending on the type of reducing agent, but is generally in the range of 0.001 to 1.00 mmol per mol of silver halide. It is within. The gold compounds used in the present invention are monovalent and trivalent soluble gold salts, such as chloroauric acid, gold thiocyanate, sodium chloroaurate, potassium chloroaurate, potassium bromoaurate, potassium iodoaurate. , potassium gold cyanide, potassium gold thiocyanide, sodium gold thiomaleate, gold thioglucose, etc. are used.

The amount of the gold compound to be used varies depending on the size composition of the silver halide grains, the purpose of application, etc., but is generally within the range of 0.0001 to 0.1 mmol per mol of silver halide. Preferably 0.005 to 0.05
Good results are obtained when used at low concentrations, in the millimolar range.

[0034] Specific examples of thiosulfate and thiocyanate used in the present invention include sodium thiosulfate, ammonium thiosulfate, potassium thiocyanate, ammonium thiocyanate, and complex salts thereof. , these compounds generally contain 0 per mole of silver halide.
．． 0003 to 10.0 mmol, preferably 0.005 to 0.5 mmol.

[0035] These thiosulfate and thiocyanate salts may be used before fogging with the reducing agent and gold, during fogging, or after fogging, but depending on the timing of use. The amount used will vary and may require increased amounts, especially if added after fogging.

The gamma of the direct positive photosensitive material of the present invention is:
It can be adjusted using conventional techniques by controlling emulsion composition, grain size distribution, chemical sensitization, and additive conditions.

Further, linearity adjustment can be obtained by mixing at least two emulsions having approximately the same gamma given by the above-mentioned method by adjusting the mixing ratio.

Other photographic additives can also be added to the direct positive silver halide emulsion according to the present invention. As a stabilizer, for example, Japanese Patent Publication Nos. 49-16053 and 49-126.
No. 51, JP-A-48-66828, etc., or triazoles, azaindenes, benzothiazolium compounds, mercapto compounds, or cadmium,
Water-soluble inorganic salts such as cobalt, nickel, manganese, and zinc may also be included.

Hardening agents include formalin, glyoxal, aldehydes such as mucochloric acid, S-triazines, epoxies, aziridines, vinyl sulfonic acid, etc., and sensitizers include, for example, Japanese Patent Publication No. 42-25203,
No. 43-10245, No. 43-13822, No. 43
-17926, 43-17927, 46-21
Polyalkylene oxides selected from those described in No. 186, No. 49-8102, No. 49-8332, and derivatives thereof may also be contained. Furthermore, it is also possible to contain a color coupler selected from those described in, for example, Japanese Patent Publication Nos. 45-24910 and 45-29878. Other brighteners, thickeners, etc. as necessary.
Preservatives and the like can also be contained.

The silver halide emulsion according to the present invention contains protective colloids such as gelatin, gelatin derivatives, polyvinyl alcohol, polyvinyl acrylate, polyvinylpyrrolidone, cellulose ethers, partially hydrolyzed cellulose acetate, and those described in Japanese Patent Publication No. 49-20530. Hydrophilic polymers such as poly-(N-hydroxylalkyl)-β-alanine derivatives grafted with ethylene oxide can be included.

Furthermore, a dispersion polymerized vinyl compound may be contained as a binder for emulsion. For example, Tokuko Sho 49-3234
Polymer latex of unsaturated ethylenically monomer emulsion polymerized in the presence of an activator as described in No. 4, Japanese Patent Publication No. 49
It is preferable from the viewpoint of improving the physical properties of the membrane to use the ceric salt described in No. 20964 to contain a polymer latex etc. in which a polymer compound having a hydroxyl group is grafted with an unsaturated ethylenic monomer. It is.

[0042] Also, from the viewpoint of emulsion technology,
As described in No. 3, No. 44-9499, the developer is protected and contained, and higher fatty acids such as liquid paraffin and higher unsaturated fatty acids such as stearyl acetoglyceride are protected and contained in order to improve film properties. Depending on the purpose, color couplers, stabilizers, etc. can also be included for protection. The direct positive silver halide emulsion thus obtained can be applied to any suitable photographic support such as glass, wood, metal, film, e.g. cellulose acetate, cellulose acetate butyrate, cellulose nitrate, polyester, polyamide, polystyrene, etc. , paper, baryta-coated paper, polyolefin-coated paper such as polyethylene or polypropylene-coated paper, etc., and the polyolefin-coated paper can be subjected to electron bombardment treatment to improve the adhesion of the emulsion.

Known photographic additives can be added to the direct positive silver halide emulsion according to the present invention.

Examples of known photographic additives include Research Disclosure's RD-1764 shown in the table below.
3 (1978) and RD-18716 (1979)
Examples include compounds described in .

The direct positive silver halide emulsion according to the present invention may contain various other known photographic additives. Examples of known additives include Research Disclosure (RD) No. 17643 (December 1978
month), same No. 18716 (November 1979) and the same No. 308119 (December 1989). The following table lists the types of compounds and their descriptions in these three research disclosures.

Additive RD-17643
RD-18716
RD-308119
Page Category Page
Classification Page Classification Chemical sensitizer 23 III 648 Upper right 996 II
I Sensitizing dye 23 IV
648~649 996~
8 IV Desensitizing dye 23
IV
998 B Dye
25-26 VIII 649-
650 1003
VIII Development accelerator 29 XXI
648 Upper right Fog suppressant/stabilizer 24 IV
649 Upper right 100
6-7 VI Brightener 24
V
998 V Hardener 26 x 65
1 left 1004~5
X Surfactant 26-7 XI
650 right 1005~6
XI Antistatic agent 27 XI
I 650 right 1
006-7 XIII Plasticizer
27 XII 650 Right
1006 XII
Slip agent 27 XII Matt agent 28 XVI 65
0 right 1008~9
XVI Binder 26 XXII
10
03-4 IX Support 28
XVII
1009 XVII

[0047]

EXAMPLES Examples of the present invention will be described in detail below. Note that, as a matter of course, the present invention is not limited to the embodiments described below.

Example 1 Preparation of seed crystal A Iodide containing 2 mol% of silver iodide with an average grain size of 0.02 μm was prepared by the double jet method at 60° C. while controlling pAg = 8.0 and pH = 2.0. Cubic grains of silver bromide emulsion were prepared. After the mixing, gelatin in which 90% of the amino groups were condensed with phenylcarbamoyl was added and stirred for 3 minutes, and then 0.13 g of potassium hydroxide/1 mole of AgX was added to adjust the pH to 4.0. After standing and decantation, 2.1 l of pure water at 40°C/1 mole of AgX,
Add potassium hydroxide 0.25/AgX1 mol and adjust the pH to 5.
．． 8 and stir for 5 minutes. Then, nitric acid (1.7N)
1.5 l/1 mole of AgX was added to adjust the pH to 4.3, and the mixture was left standing and decanted. Further, gelatin and 0.2 g of potassium hydroxide/1 mol of AgX were added to adjust the pH to 5.8 and redisperse to obtain seed crystals A.

Growth from Seed Crystal A The above seed crystal was dissolved in a gelatin solution kept at 40°C.
Furthermore, ammonia was added to adjust the pH to 8.0. Rhodium trichloride and potassium hexachloroiridate were each added in an amount of 0.12 mg per mole of silver halide to this solution, and after 2 minutes, a 1N ammoniacal silver nitrate aqueous solution and a 1N potassium bromide aqueous solution were added by a double jet method. The pH during mixing was controlled at 8.0 and the EAg at -10±2 mV. After the mixing was completed, the pH was lowered to 6.0 with acetic acid. Thereafter, desalting was performed in the same manner as for the seed crystals to obtain an emulsion. The pH of the emulsion thus obtained was adjusted to 6.8.
0.3 thiourea dioxide per mole of AgX at °C
mg, sodium thiosulfate 1.2 mg and chloroauric acid 1.
5 mg was added and aged until a suitable fog was obtained. Latex particles shown in Table 1 were added to each emulsion, and a spreading agent, hardener, wetting agent, thickener, and stabilizer were added to prepare an emulsion coating solution. In addition, a nonionic surfactant was added to the gelatin solution as a protective film coating solution, and a spreading agent, a hardening agent, and polymethyl methacrylate particles were added as matting agents as shown in Table 1. These solutions were simultaneously layered on a polyethylene terephthalate base coated with an undercoat layer under coating conditions such that the protective layer thickness/emulsion layer thickness was >0.5 and the total film thickness was 5 μm or less, coated, dried, and prepared as a sample. Created.
Incidentally, the coating amount per 1 m2 was 3 g in terms of silver.

[0050] The samples thus obtained were subjected to natural aging and forced deterioration treatment (50°C, 80% RH).
3 days) and then exposed using an optical wedge to create sensitometric test samples and quarter-cut test samples with a density of 1.0 to 1.3 by solid exposure.
501 (manufactured by Konica Co., Ltd.), developer XD-SR,
Each sample was processed for 45 seconds using fixer XF-SR (both manufactured by Konica Corp.), and the sensitivity, fog, gamma, linearity, roller marks, processing unevenness, and pick-offs (processing scratches) appearing on the film surface were evaluated. The results are shown in Table 1. The evaluation standard sensitivity was obtained by calculating the reciprocal of the amount of light required for the blackening density to increase by 1.0, and using Comparative Sample No. It is expressed as a relative sensitivity when the sensitivity of 1 is set as 100. Linearity is evaluated using the difference in the logarithm of the exposure dose (ΔLogE) at a point on the characteristic curve that has the same density as an arbitrary point on a straight line connecting two points of optical density that define gamma on rectangular coordinates. Expressed as maximum value. When this value is 0.02 or less, linearity is excellent.

[0051] Roller marks and processing unevenness have a density of 1.0
The four-cut film finished with a rating of ~1.3 was visually judged and evaluated using a four-step evaluation method.

Evaluation criteria for roller marks A: No roller marks observed. B: Some roller marks occurred. C: Significant roller marks occurred. D: Significant roller marks occurred. Evaluation criteria for development unevenness A: No processing unevenness observed.

B: Some processing unevenness occurred.

C: Considerable unevenness occurred in processing.

D: Significant processing unevenness occurred.

Pickoffs (processed scratches) The state of pickoffs in the quartered film was visually observed and evaluated using the following four-level evaluation method.

A: Occurrence of pickoff is observed.

B: A slight pickoff occurred.

C: A considerable amount of pickoff occurred.

D: Significant pick-off occurred.

The results obtained are shown in Table 1.

[0062]

[Table 1]

[0063]

[Table 2]

As is clear from Table 1, by containing latex in the emulsion and containing a matting agent in the protective layer and applying a thin film, pressure resistance is improved and high sensitivity and ultra-quick processing are possible. It can be seen that a direct positive silver halide photographic material can be obtained.

[0065]

EFFECTS OF THE INVENTION According to the present invention, a direct positive type silver halide photographic light-sensitive material having low fog, high maximum density and excellent linearity was obtained. Furthermore, according to the present invention, it was possible to prevent processing unevenness, processing scratches, and roller marks from occurring during rapid development.

Claims (2)

[Claims] Claim 1: In the constituent layers of a direct positive silver halide photographic light-sensitive material that has been fogged in advance, the thickness of the protective layer on the emulsion layer is 1.1 μm to 3.0 μm, and the thickness of the protective layer and the emulsion layer is 1.1 μm to 3.0 μm. ratio is 0.5 or more, and the total thickness of the emulsion layer and the protective layer is 5 μm or less, and the protective layer has an average grain size of 4 μm.
Contains a matting agent of less than m and has a total photographic processing time of 60
A direct positive type silver halide photographic light-sensitive material characterized by a photosensitive time of less than a second. 2. The direct positive silver halide photographic material according to claim 1, wherein the emulsion layer contains latex grains made of a hydrophobic polymer.