JPS6335966B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a silver complex diffusion transfer method (DTR method). In the DTR process, silver complex salts are imagewise transferred by diffusion from a silver halide emulsion layer to an image-receiving layer, and they are converted into a silver image, often in the presence of physical development nuclei. For this purpose, an imagewise exposed silver halide emulsion layer is placed in contact with, or brought into contact with, an image-receiving layer in the presence of a developing agent and a silver halide complexing agent, and the unexposed Converts silver halide to soluble silver complex salt. In the exposed parts of the silver halide emulsion layer, the silver halide is developed to silver (chemical development);
Therefore, it cannot be dissolved further and therefore cannot be diffused. In the unexposed portions of the silver halide emulsion layer, the silver halide is converted to soluble silver complex salts, which are transferred to the image-receiving layer where they form a silver image, usually in the presence of development nuclei. In the DTR method for document reproduction or especially for the production of printing materials, high maximum concentrations,
It is important to obtain silver images of high contrast and sharpness. Furthermore, the image reproduction characteristics, that is, the ability to reproduce an image as faithful as possible to the original, for example, a ruled line with a line width of several tens of microns, into a thin line image with the same line width, especially positive image ruled lines (black lines) on a white background. ) and negative image lines (white lines) on a black background, faithfully reproducing all the ruled lines of the manuscript.
Or print a continuous tone original through a screen,
It is extremely important to reproduce a good halftone image by diffusion transfer development. It is recognized that the image reproduction characteristics become extremely poor, especially when the photosensitive material has a high photosensitivity to the extent that an original is photographed by camera work. U.S. Patent No. 3501305, U.S. Patent No. 3501306, U.S. Patent No.
No. 3501307, No. 3531290, etc. describe high-sensitivity direct positive silver halide emulsions suitable for camera work. A DTR method using a direct positive silver halide emulsion is also known. However, DTR methods using direct positive silver halide emulsions containing electron acceptors or halogen acceptors have extremely slow diffusion transfer speeds, resulting in low maximum density, low contrast, low sharpness, and poor image reproduction. It has a serious drawback of not having good characteristics.
Moreover, transferred silver images often exhibit metallic luster, which impairs commercial value, but generally, as the transfer speed increases, metallic luster is more likely to occur, and the above-mentioned drawbacks cannot be easily solved with ordinary development accelerators. . An object of the present invention is to provide a silver complex diffusion transfer method that improves the above-mentioned drawbacks regarding transfer speed, maximum density, contrast, sharpness, image reproduction characteristics, and metallic luster. Another object of the present invention is to provide a silver complex diffusion transfer method which improves the above-mentioned drawbacks of high-sensitivity direct positive silver halide emulsions containing electron acceptors or halogen acceptors. The above-mentioned objects of the present invention are to achieve the following when conducting silver complex diffusion transfer development using a direct positive silver halide emulsion containing an electron acceptor or a halogen acceptor.
It has been found that this can basically be achieved by a silver complex salt diffusion transfer method, which is characterized in that a developer-soluble iodide is placed in a state where it is not in contact with the silver halide grains of the emulsion and then developed. The present invention will be explained in more detail below. US Pat. No. 3,531,290 describes a direct positive silver halide emulsion that can be preferably used in the present invention. i.e. chloride is 50
An electron acceptor or a halogen acceptor and an amount of water-soluble bromide or bromide and iodide necessary for increasing sensitivity are added to a fogged silver halide emulsion in an amount of mol % or more. In addition, Japanese Patent Publication No. 46-43431 discloses that a silver halide emulsion containing 50 mol% or more of bromide, which is fogged with a reducing agent and a noble metal (for example, gold) with a nobler potential than silver, has an electron acceptor and a water-soluble emulsion. It is described that high sensitivity can be achieved by adding iodide. However, even if the DTR method is carried out using any of the direct positive silver halide emulsions described in the above-mentioned patent specifications, the purpose of the present invention will hardly be achieved depending on the iodide added. cannot be achieved at all. In other words, it is not appropriate to directly add the iodide used in the present invention to a positive silver halide emulsion. This is because it inevitably causes contact with silver halide grains. However, coating solutions for forming hydrophilic colloid layers adjacent to direct positive silver halide emulsion layers, such as subbing layers or protective layers, may contain some iodine, although some diffusion into the emulsion layer may occur. It is possible to add the compound by using a large amount of the compound. If problems arise due to diffusion into the emulsion layer, care should be taken to minimize the amount of iodide added to the hydrophilic colloid layer adjacent to the emulsion layer. Iodides soluble in the diffusion transfer developer may also be included in the hydrophilic colloid layer of the image-receiving material, usually in the physical development nucleus content. The most preferred arrangement of iodide is to include it in the diffusion transfer developer. In other words, the present invention typically includes a diffusion transfer developer containing an amount of alkali-soluble iodide necessary to achieve the object of the present invention. Arrangement in the hydrophilic colloid layer is also included as an arrangement mode in which iodide has the same effect on diffusion transfer development. Preferred examples of the alkali-soluble iodides used in the present invention include water-soluble iodides such as potassium, sodium, lithium, ammonium, and strontium. Organic iodide compounds can also be used as long as there are no disadvantages. The amount of alkali-soluble iodide used is in the range of 0.001 to 6.0 mmol, preferably 0.005 to 3.0 mmol of iodine, per diffusion transfer developer. The amount applied to the hydrophilic colloid layer is based on the developer absorption amount per unit area of the material (absorption amount under conditions according to the normal DTR method), and the amount to be applied to the developer described above is a guideline. can be determined. As mentioned above, when directly applying to a layer adjacent to a positive silver halide emulsion layer, it is necessary to use a certain amount more than the above-mentioned guideline amount because of the diffusion of iodide. Generally, the developer absorption capacity of the material ranges from about 5 grams ^per square meter to about 30 grams per square meter. The amount of alkali-soluble iodide used can be changed to a certain extent depending on conditions such as the amount of silver and the composition of silver halide.
It can also be placed at multiple locations. The use of iodides in diffusion transfer developers is known (see, for example, Japanese Patent Publication No. 11630/1983). However, iodide, like bromide, was only known as an antifoggant or a development inhibitor. The present invention uses a direct positive silver halide emulsion containing an electron acceptor or a halogen acceptor.
When carrying out the DTR method, when iodide is arranged so as to act on the silver halide grains during diffusion transfer development, the diffusion transfer development speed can be significantly increased, and despite this, the transfer silver image remains It can eliminate metallic luster and has the highest density.
It has been found that the contrast, sharpness, and image reproduction characteristics can be significantly improved, and it will be understood that this is a surprising effect that could not have been predicted by the conventional DTR method. It goes without saying that if the amount of iodide used is too small, the effect of the present invention will be insufficient, but if it is too large, it will again act as a fog suppressor or development suppressant as in the past. Therefore, it goes without saying that the optimum amount should be determined depending on the constituent factors and development conditions. The electron acceptor used in the present invention is characterized by its bolarographic half-wave potential, ie, its redox potential determined by bolarography. Electron acceptors useful in the present invention are those in which the sum of the bolarographic anodic potential and the bolarographic cathodic potential is positive. Methods for measuring these redox potentials are described, for example, in U.S. Patent No.
It is described in the specification of No. 3501307. A particularly effective electron acceptor for use in the present invention is the imidazo[4,5-b]quinoxaline cyanine dye described in Belgian Patent No. 660,253. Another particularly effective electron acceptor is an indole cyanine dye having an aromatic substitution at the 2-position, which is described in US Pat. No. 3,314,796 and US Pat. No. 3,505,070. Further examples of effective electron acceptors are those described in US Pat. Nos. 3,501,310, 4,097,285, and 4,259,439. However, it goes without saying that the invention is not limited to these. Specific examples of electron acceptors used in the present invention include:
1.1′-dimethyl-2.2′-diphenyl-3.3′-indolocarbocyanine bromide, 2.2′-di-p-
Methoxyphenyl-1,1'-dimethyl-3,3'-indolocarbocyanine bromide, 1,1'-dimethyl-2,2',8-triphenyl-3,3'-indolocarbocyanine perchlorate, 1,3
-Diallyl-2-[2-(9-methyl-3-carbazolyl)vinyl]imidazo[4,5-b]quinoxalium p-toluenesulfonate, 1,3-
Diethyl-1'-2'-phenyl imidazo [4,5
-b] Quinoxalino-3'-indolocarbocyanine iodide, 1,1',3,3'-tetraethylimidazo[4,5-b] Quinoxalinocarbocyanine chloride, 1,1',3,3 '-Tetramethyl-2-phenyl-3-indropyrrolo[2,
3-b] Pyridocarbocyanine iodide,
1,1',3,3,3',3'-hexamethylpyrrolo[2,3-b]pyridocarbocyanine perchlorate, 1,1',3,3-tetramethyl-5-nitro-2 '-phenylindo-3'-indocarbocyanine iodide, 1,1',3,3,3',
3'-hexamethyl-5,5'-dinitroindocarbocyanine p-toluenesulfonate, 3'-ethyl-1-methyl-2-phenyl-6'-nitro-
3-indrothiacarbocyanine p-toluenesulfonate, pinacryptol yellow, 5
-m-nitrobenzylidenerhodanine, 5-m-
nitrobenzylidene-3-phenylrhodanine,
Examples include iodide of 1,3-diethyl-6-nitrothia-2'-cyanine iodide. In the present invention, in addition to the electron acceptor, a known sensitizing dye can also be used in combination. The halogen receptor used in the present invention is
A polarographic anodic potential of less than 0.85 and −1.0 as described in U.S. Pat. No. 3,531,290.
It has a more negative polarographic cathode potential. For example, 3-carboxymethyl-5-
[3(3-methyl-2(3)-thiazolinylidene)isopropylidene]rhodanine, 3-ethyl-5-
[1-(4-sulfobutyl)-4(1H)-pyridylidene]rhodanine sodium salt, 1-carboxymethyl-5-[(3-ethyl-2-benzothiazolinylidene)ethylidene]-3-phenyl-2 -thiohydantoins, etc., which are described in the above patent specifications, are cited herein. In this specification, the electron acceptor or halogen acceptor is 0.2 to 2.0 per mole of silver halide.
g preferably 0.3 to 1.5 g, particularly preferably 0.4 to 1.5 g
Used in concentrations ranging from 1.0g. If desired, an electron acceptor and a halogen acceptor can be used in combination. The silver halide emulsion used in the present invention may be prepared by any method such as an acid method, a neutral method, or an ammonia method. The silver halide emulsion used in the present invention may be any of silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver iodobromide, or silver chloroiodobromide emulsion. good. In particular, a highly sensitive direct positive silver halide emulsion comprising silver halide containing 50 mol % or more of chloride as described in US Pat. No. 3,531,290 is preferred. The silver halide emulsion used in the present invention may be monodisperse or non-monodisperse, but monodisperse emulsions are preferred. Furthermore, the silver halide emulsions used in the present invention may be regular or irregular.
This also includes things, but regular things are preferable. The silver halide emulsion used in the present invention includes, for example, one prepared by the method described in US Pat. No. 3,367,778. In this type of emulsion, the interior of the grain is chemically sensitized or fogged and covered with an outer shell. The direct positive silver halide emulsion used in the present invention can be fogged with a chemical fogging agent. As a method of imparting such fog, for example, Antoine Auto
scienceet by Antoine Hautot and Henri saubeneir.
lndustries Photograpligues) 28, 1-23, and
57-65 (1957) is effective. The direct positive silver halide emulsion of the present invention is preferably fogged using a combination of a reducing agent described in US Pat. No. 3,501,307 and a metal compound having a more noble potential than silver. Specific examples of the reducing agent used in the present invention include thiourea dioxide, hydrazine derivatives, formaldehyde, stannous chloride, and amine borane. Also,
Specific examples of metal compounds with a more noble potential than silver used in the present invention include gold compounds (e.g., chloroauric acid, potassium chloroaurate, etc.), platinum compounds (e.g., potassium chloroplatinate, sodium chloroplatinate, etc.), and iridium. compounds (eg, potassium hexachloroiridate, iridium tripromide, etc.), and the like. The direct positive silver halide emulsion of the present invention is preferably fogged with a metal compound having a more noble potential than silver. Specific examples of metal compounds having a more noble potential than silver are as described above. The direct positive silver halide emulsion of the present invention can be produced using the above method and a sulfur-containing compound (for example, sodium thiosulfate, potassium thiosulfate, allylthiourea,
etc.) or a thiocyanate compound (for example, potassium thiocyanate, ammonium thiocyanate, etc.). Protective colloids for the direct positive silver halide emulsion used in the present invention include natural products such as gelatin, modified gelatin, albumin, agar, acacia, alginic acid, polyvinyl alcohol/polyvinylpyrrolidone, acrylamide, acrylic acid, and vinyl. Examples include water-soluble synthetic resins such as imidazole copolymers. The direct positive silver halide emulsion of the present invention may contain stabilizers, development accelerators, brighteners, surfactants, hardeners, dye removal improvers, thickeners, etc., as necessary. . The direct positive silver halide emulsion of the present invention can be applied onto a suitable support such as cellulose acetate film, polyethylene terephthalate film, paper, baryta coated paper, polyolefin (e.g. polyethylene, polypropylene, etc.) coated paper. applied. These supports may be corona treated and, if necessary, subbed using known methods. Further, the support may be colored for the purpose of preventing halation, or may be provided with an antihalation layer. The image-receiving material has a layer containing physical development nuclei, such as heavy metals or sulfides thereof. The processing liquid used in the DTR method contains alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and trisodium phosphate. Preservatives such as sodium sulfite, thickening agents such as carboxymethylcellulose, hydroxyethylcellulose, antifoggants such as potassium bromide, silver halide solvents such as sodium sulfate, toning agents such as 1-
phenyl-5-mercapto-tetrazole, development modifiers such as polyoxyalkylene compounds, onium compounds, developers such as British Patent No.
1001558 and, if necessary, a developing agent such as hydroquinone, 1
-Phenyl-3-pyrazolidone, hydroxylamine, etc. are contained. The pH of the processing solution is the pH that activates development, usually about 10~
14, preferably about 12-14. a certain
The optimum pH in the DTR method varies depending on the photographic element used, the desired image, the type and amount of various compounds used in the processing liquid composition, etc. EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited in any way. Example 1 By double jet method, the average particle size was
A 0.3 micron silver chlorobromide (silver chloride 95 mol%) gelatin emulsion was prepared, coagulated and precipitated, and then washed with water.
After redissolving this emulsion and adding gelatin, 0.2 mg of thiourea dioxide per mole of silver was added and the pH
7.0 and aged for 60 minutes at 60°C, then 4 mg of potassium chloroaurate per mole of silver was added and aged for an additional 60 minutes. The temperature was lowered to about 40°C and the pH was lowered to 5.0, and 400 mg of pinacryptol yellow and 300 mg of the following dyes were added per mole of silver to the above emulsion. After adding 8 g of potassium bromide and 1 g of potassium iodide, hardeners, surfactants, etc. were added to form a finished emulsion, which was deposited on corona discharge treated polyethylene coated paper support at 1.5 g/m of silver. ² together with a protective layer coating solution (gelatin 1.0 g/m ² ) and dried. On the other hand, on one side of the same support as above, an image receiving layer consisting of gelatin containing nickel sulfide cores and a processed product of ethylene maleic anhydride copolymer and polyvinyl alcohol (weight ratio 1:1) was placed with a dry weight of hydrophilic colloid of 3 g/m2. An image-receiving sheet was prepared by providing the number of sheets so as to be equal to ² . After applying a sensitometric exposure to the photosensitive material by overlaying a contact screen on half of a wettable tablet with a density difference of 0.15, it is overlaid with an image-receiving sheet, passed through a conventional processor containing the following diffusion transfer developer, and then processed with a squeegee.・After exiting the roller 5,
Both sheets were peeled off after 15, 30 and 60 seconds. The processing liquid temperature was 20°C. <Diffusion transfer developer> Water 700ml Sodium sulfite (anhydrous) 50g Sodium hydroxide 12g Hydroquinone 11g 1-phenyl-3-pyrazolidone 1g Sodium thiosulfate (pentahydrate) 20g Potassium bromide 1g N-methyl-aminoethanol 10ml Iodide Potassium Xg Adjust to 1 with water Using the above developer containing no potassium iodide as a standard, tests were conducted by varying the amount of potassium iodide used. Table 1 shows the maximum density (maximum exposure amount portion of the photosensitive material) obtained in the image-receiving layer at each peeling time.

Table 1 The results in Table 1 show that potassium iodide significantly accelerates the diffusion transfer development rate. In addition, when potassium iodide was not included, the transferred silver had a metallic luster when it was peeled off after 30 and 60 seconds, whereas when potassium iodide was included, the metallic luster disappeared in both cases. The image had a higher maximum density, higher contrast, and sharper minute halftone dots. Example 2 Four types of direct positive silver halide photosensitive materials were prepared in the same manner as in Example 1 except that 350 mg of pinacryptol yellow and 250 mg of the following dyes A, B, C or D were contained per mole of silver halide emulsion. was prepared, and thereafter the DTR method was performed in the same manner as in Example 1. The same results as in Example 1 were obtained. Reference example Silver chlorobromide emulsion containing 5 mol% bromide (average grain size
0.3 micron, cube) was chemically sensitized, and 150 mg of the following dye was added per mole of silver halide.
A hardening agent, a surfactant, etc. were added, and the coating was coated on a polyethylene-coated paper support with a coating solution for forming a protective layer (gelatin 1 g/m ² ) to a silver concentration of 1.5 g/m ² , dried and fogged. According to Example 1, using the image receiving sheet of Example 1,
DTR method was implemented. In a diffusion transfer developer containing potassium iodide, the diffusion transfer development rate was suppressed as the amount of potassium iodide was increased, and the effects of the present invention could not be obtained. Example 3 A gelatin layer containing carbon black and a gelatin layer containing titanium dioxide were provided on a polyethylene-coated paper support, and the direct positive silver halide emulsion layer of Example 1 and a protective layer (hydroxyethyl cellulose 1 g/m ² ). The image-receiving sheet of Example 1 was treated with the following diffusion transfer developer (20° C.) and peeled off after 10 seconds and 30 seconds. <Diffusion transfer developer> Water 700ml Anhydrous sodium sulfite 40g Potassium hydroxide 15g Sodium thiosulfate 15g Potassium bromide 1g Potassium iodide 0.08g Hydroquinone 10g 1-phenyl-3-pyrazolidone 1g 1-phenyl-5-mercaptotetrazole 0.1g Water Set it to 1. The maximum density was 1.38 for peeling after 10 seconds and 1.75 for peeling after 30 seconds, and a high contrast, sharp silver image without metallic luster was formed. Example 4 1 m ² was added to the gelatin coating solution for forming a protective layer in Example 1.
The following compound in an amount of 0.005 mmol and 0.05 mmol as iodine per Example 1 was repeated except that . A diffusion transfer developer containing no iodide was used.
Results similar to those in Example 1 were confirmed.

Claims (1)

[Scope of Claims] 1. In a method of silver complex diffusion transfer development using a direct positive silver halide emulsion containing an electron acceptor or a halogen acceptor, no contact is made with the silver halide grains of the emulsion. A silver complex diffusion transfer method in which iodide soluble in a developer is placed in a state where it is developed. 2. The silver complex diffusion transfer method according to claim 1, which contains 0.001 to 6.0 mmol of iodide as iodine per developer. 3. The silver complex salt diffusion transfer method according to claim 1, which contains 0.005 to 3.0 mmol of iodide as iodine per developer. 4. The silver complex salt diffusion transfer method according to claim 1, which utilizes a direct positive silver halide emulsion containing an electron acceptor or a halogen acceptor at a concentration of 0.4 to 1.0 g per mole of silver halide. 5. The silver complex salt diffusion transfer method according to claim 4, which is a silver halide emulsion containing 50 mole percent or more of chloride.