JPH01100545A - Image receiving element by silver salt transfer method - Google Patents

Abstract

PURPOSE:To obtain an image receiving element which yields a silver image of good color tones with the high max. density, high contrast and high sharpness by incorporating the colloidal dispersion of metal palladium reduced by ascorbic acid in a hydrophilic colloid soln. as a physical development nucleus material into this element. CONSTITUTION:This image receiving element contains the colloidal dispersion of the metal palladium reduced by the ascorbic acid in the hydrophilic colloid soln. as the physical development nucleus material. The molar ratio of the palladium ions and ascorbic acid used for prepn. of the physical development nucleic to be used is between 1:1 and 1:10 and is more preferably between 1:2 and 1:4. The most preferable example of the hydrophilic colloid used for prepn. of the physical development nucleic is poly-N-vinyl pyrolidone. A soln. having 0.5-20wt.% solid content of the hydrophilic colloid material is used as the hydrophilic colloid soln. The temp. at the time of preparing the physical development nucleic is adequately from 30 deg.C-50 deg.C. The silver image having the good color tones is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image receiving element for use in silver salt diffusion transfer, and more particularly to a silver salt diffusion transfer image receiving element having improved image quality.

(Prior art) The principle of the silver salt diffusion transfer method is described in U.S. Patent No. 2,352°01.
It is stated in No. 4 etc. That is, in the silver salt diffusion transfer method, the silver halide emulsion layer exposed in accordance with the image is
It is placed or brought into contact with the image-receiving layer in the presence of a developing agent and a silver halide solvent to convert the unexposed silver halide to a soluble silver complex. In the exposed parts of the silver halide emulsion layer, the silver halide is developed to silver so that it can no longer be dissolved and therefore cannot be diffused. In the unexposed portions of the silver halide emulsion layer, the silver halide is converted to soluble silver complexes which are transferred to the image receiving layer where they form a silver image, usually in the presence of physical development nuclei.

In a direct positive silver halide emulsion, the effects of exposed and unexposed silver halide are reversed.

The silver salt diffusion transfer method has a wide range of applications.

Among other things, in the process for the production of printing materials it is necessary to obtain silver images of high maximum density, high contrast and high sharpness in the image-receiving layer. Furthermore, the image reproduction characteristics, that is, the characteristics of reproducing an image as faithful as possible to the original, are particularly important for originals that have a mixture of positive image ruled lines (black lines) on a white background and 1m negative image ruled lines (white lines) on a black background. It is extremely important to faithfully reproduce ruled lines, or to reproduce a good halftone image by printing a continuous tone original through a screen and performing diffusion transfer development.

Furthermore, in the silver salt diffusion transfer method, a continuous tone transferred silver image can be obtained depending on the design of the silver halide emulsion layer. In this case, the important qualities are rich tones and obtaining a neutral gray tone from a high density region to a low density region.

It is well known that a toning agent is usually used in the image receiving element in the silver salt diffusion transfer method. For example, typical examples include 1-phenyl-5-mercaptotetrazole and other color toning agents described in Photographic Silver Halide Daylight, -John Process, published by Focal Press, p. 61. However, these toning agents have the disadvantage of lowering transfer density and transfer speed. Furthermore, the use of known toning agents is largely insufficient to obtain neutral gray silver images from low to high density areas in continuous tone images.

The color tone of the transferred silver image also changes depending on the type of physical development nuclei. - Examples of physical development nuclei include heavy metals such as silver, gold, platinum, palladium, copper, cadmium, lead, cobalt, and nickel, or their sulfides and selenides. These physical development nuclear materials can be prepared by reducing the corresponding metal ions to create a metal colloid dispersion, or by mixing a metal ion solution with a soluble sulfide or selenide solution to form water-insoluble metal sulfides or metal selenides. obtained by making a colloidal dispersion of Furthermore, it is known that even if the metals, metal sulfides, or selenides are of the same type, physical development nuclei having different physical properties such as shape depending on the method of preparation affect the color tone of the transferred silver image.

However, depending on the selection of physical development nuclei, even if the high-density area becomes neutral, the low-density area may be brownish-brown, or even if a neutral color that is satisfactory to some extent is obtained, the density may decrease significantly. However, completely satisfactory results have not been obtained.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an image-receiving element that provides a silver image with high maximum density, high contrast, high sharpness and good tone.

Another object of the invention is to provide an image receiving element which provides a good silver image with improved image reproduction characteristics.

Another object of the present invention is to provide an image-receiving element that provides continuous tone images with good color tones, especially without the use of toning agents.

(Means for Solving the Problems) The above aspects of the present invention are characterized in that a metal palladium colloid dispersion reduced with ascorbic acid is contained as a physical development nucleus material in a suitable hydrophilic colloid solution. Achieved by image receiving elements.

As a result of intensive research on improving color tone and image quality by the preparation method of reduced metallic palladium, the present inventor found that good results can be obtained when ascorbic acid is used as a reducing agent to reduce palladium ions.

It is conventionally known that colloidal dispersions of di-membered metals can be used as physical development nuclei. In this case, the metal ions are usually reduced to obtain a metal colloid dispersion. There are various methods for reducing metal ions, such as U.S. Pat.
, 647,440, 4,204,869, 4,209,330, 4,281,056, 4,282,307, etc. There is. However, the present inventor has attempted to use an image-receiving element using a metallic palladium colloidal dispersion prepared by a method similar to these as a physical development nucleus, and the image-receiving element is generally used for document reproduction or preparation of printing plate materials. Diffusion transfer processing using emulsions mainly consisting of silver chloride did not always give good results. That is, the silver images had extremely high surface gloss, and the silver images had an extremely reddish-brown color, which were by no means desirable. The present inventor also attempted to reduce palladium ions using various other reducing agents, and found that only the image-receiving element of the present invention containing a colloidal dispersion of metal palladium reduced with ascorbic acid as physical development nuclei was mainly silver chloride. In diffusion transfer processing using this emulsion, silver images with high maximum density, low surface gloss, and good color tone were obtained.

Further, only the receiving element of the present invention was capable of forming neutral gray continuous tone silver images without the use of toning agents and without loss of maximum density.

The molar ratio of palladium ions and ascorbic acid used in the preparation of physical development nuclei used in the present invention is 1:1 to 1=10.
preferably between 1:2 and 1:4.

The most preferred example of the hydrophilic colloid used in the preparation of physical development nuclei is poly-N-vinylpyrrolidone, but other commonly used hydrophilic colloid substances such as gelatin,
Carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide, acrylamide-vinylimidazole copolymer, and the like can be used alone or in combination.

As the hydrophilic colloid solution, a solution containing a solid hydrophilic colloid substance in an amount of 0.5 to 20% by weight is used.

The pH during the preparation of physical development nuclei may be arbitrary, but is preferably weakly acidic. The temperature is arbitrary between 10°C and 70°C, but preferably between 30°C and 50°C. After mixing palladium ions and ascorbic acid, the time required for physical development to produce a nuclear material varies depending on the temperature, but at 40°C it takes about 1
It takes more than a minute.

The physical development nuclei contained in the image-receiving layer are about 1X10-' to about 1X10-5 mol/r in terms of the amount of metal palladium.
r? is a quantity in the range of .

Binders for the image-receiving layer include gelatin, phthalated gelatin, acylated gelatin, phenylcarbamylated gelatin, carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, polyvinyl alcohol,
Partially saponified polyvinyl alcohol, heat-processed products of polyvinyl alcohol and maleic anhydride copolymers (e.g., styrene-maleic anhydride, ethylene maleic anhydride, etc.), polyacrylamide, poly-N-vinylpyrrolidone, latexes (For example, a single or copolymer of polyacrylic ester, polymethacrylic ester, polystyrene, polybutadiene, etc.) can be used alone or in combination.

The image-receiving layer can be hardened with a suitable hardening agent. Specific examples of hardening agents include aldehyde compounds such as formaldehyde and geltaraldehyde, ketone compounds such as diacetyl and cyclopentanedione, and bis(2 -chloroethylurea)-2-hydroxy-4,6-dichloro-1
, 3,5) riazine, a compound with a reactive halokene as described in U.S. Pat. No. 3,288,775, divinyl sulfone, a compound with a reactive olefin as described in U.S. Pat. No. 3,635,718. , U.S. Patent No. 2,73
N-methylol compounds as described in US Pat. No. 2,316, incyanates as described in US Pat. No. 3,103,437, US Pat. No. 3,017,280, US Pat.
Aziridine compounds such as those described in US Pat. No. 611, U.S. Pat.
．． 100,704, epoxy compounds as described in U.S. Pat. No. 3,091,537, halogenocarboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, potassium alum. , inorganic hardeners such as zirconium sulfate, etc., and these may be used alone or in combination of two or more.

The image-receiving layer contains a surfactant (e.g., natural surfactant such as saponin, nonionic surfactant such as alkylene oxide type, glycerin type, glycidol type, etc., higher alkylamines, quaternary ammonium salts, and other heterocyclic surfactants such as saponin). cationic surfactants such as sulfoniums, anionic surfactants containing acidic groups such as carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester groups, phosphoric ester groups, amino acids,
Aminosulfonic acids, amphoteric surfactants such as sulfuric acid or phosphoric acid esters of amino alcohols, fluorinated anions containing fluorine, amphoteric surfactants, etc.), matting agents, fluorescent dyes, anti-tarnishing agents, color toning agents (such as typical Examples include 1-phenyl-5-mercaptotetrazole, other toning agents described in Photographic Silver Halide Diffusion Process, published by Focal Press, p. 61), developing agents (e.g., hydroquinone and its derivatives, 1-phenyl- 3-pyrazolidone and its derivatives, etc.), silver halide solvents (for example, sodium thiosulfate, ammonium thiosulfate, sodium thiocyanate, potassium thiocyanate, etc.), and the like.

Further, an over layer may be provided on the image receiving layer, a neutralizing layer below the image receiving layer, and a subbing layer for improving adhesion to the support.

As mentioned above, the silver halide emulsion used in the photosensitive layer of the photosensitive material for silver salt diffusion transfer according to the present invention is preferably an emulsion containing mainly silver chloride, but is not limited to this. Emulsions commonly used in diffusion transfer, such as silver bromide, silver bromide, Silver iodide, silver chloride, silver chlorobromide, silver iodobromide,
Mention may be made of silver chloroiodide, silver chloroiodobromide and mixtures thereof.

Silver halide emulsions can be sensitized in a variety of ways when they are manufactured or coated. For example, by sodium thiosulfate, alkylthiourea,
Alternatively, it may be chemically sensitized by a method well known in the art, such as with a gold compound, such as gold rhodan, gold chloride, or a combination of both. In addition, commonly used spectral sensitization can be performed.

The binder for the photosensitive layer may be a polymeric substance that is normally used in the production of silver halide emulsions, such as the binder described for the image-receiving layer. Further, the photosensitive layer can be hardened using a suitable hardening agent as described for the image-receiving layer. Furthermore, the photosensitive layer contains additives generally used in silver halide photosensitive materials, such as surfactants, anti-capri agents, matting agents,
Fluorescent dyes and developing agents (eg, hydroquinone and its derivatives, 1-phenyl-3-pyrazolidone and its derivatives, etc.) can be used. Furthermore, in addition to the photosensitive layer, auxiliary layers such as an undercoat layer, an intermediate layer, a protective layer, and a release layer may be provided as necessary.

The support for the silver salt diffusion transfer photosensitive material and image-receiving material according to the present invention is any commonly used support. They include paper, glass, films, e.g. cellulose acetate films, polyvinyl acetal films, polystyrene films, polyethylene phthalate films, etc., metal supports coated on both sides with paper, coated on one or both sides with alpha-olefin polymers, e.g. polyethylene. Coated paper supports can also be used.

In general, the silver salt diffusion transfer method is divided into the so-called "mono-sheet method" in which the light-sensitive material and the image-receiving material are formed on the same support, and the so-called "mono-sheet method" in which the light-sensitive material and the image-receiving material are formed on separate supports. There is a so-called "two-sheet" method, in which two materials are stacked and pressed together with a roller to perform diffusion transfer and then peeled off, and the present invention is applicable to either of these methods.

The treatment liquid for silver salt diffusion transfer in the present invention can have a composition of a usual silver salt diffusion transfer treatment liquid.

That is, developing agents for developing exposed silver halide, such as hydroquinone and its derivatives, 1-
Solvents for undeveloped silver halide, such as phenyl-3-pyrazolidone and its derivatives, such as sodium thiosulfate,
Additives such as ammonium thiosulfate, sodium thiocyanate, potassium thiocyanate, sodium sulfite as a preservative, potassium bromide as a development inhibitor, 1-phenyl-5-mercaptotetrazole as a color toner, alkaline substances such as sodium hydroxide. , potassium hydroxide, lithium hydroxide, tertiary phosphate), thickening agents such as Eva, carboxymethyl cellulose, hydroxyethyl cellulose, etc.

The present invention will be explained below with reference to Examples, but the present invention is not limited in any way.

Example 1 - 0.5 mol A aqueous solution of palladium chloride (dissolved with addition of common salt) in 50 g of a 3% aqueous solution of N-vinylpyrrolidone and 0.5 mol A of t-ascorbic acid.
After mixing with 0.5 m of a 15 mol/L aqueous solution with vigorous stirring and reacting at 40°C for 10 minutes, the gelatin solution was added to an aqueous gelatin solution of an appropriate concentration, and a 90 t/rr gelatin solution was coated on both sides with polyethylene that had been previously treated with corona discharge. ? On one side of the paper support, a gelatin image-receiving layer containing palladium was placed on one side of the paper support at a dry weight of 2 t/rr of hydrophilic colloid. The image receiving material of the present invention was produced in the following manner. Comparative samples were also prepared in the same manner by reducing the palladium chloride solution using ferrous ions, stannous ions, and sodium borohydride.

The light-sensitive material is prepared on the same paper support as the image-receiving material by providing an undercoat layer containing carbon black to prevent haley silon, and on top of this is an ortho-sensitized silver chlorobromide (bromochloride) with an average particle size of 0.3μ. Silver oxide 5 mol%) converted to silver nitrate is 1.5f/
d, and 0.2 cm back of 1-phenyl-3-pyrazolidone and 0.7 f/lr? A gelatin silver halide emulsion layer containing hydroquinone and gelatin was prepared.

Lay the emulsion surface of the light-sensitive material exposed for sensitometry and the image-receiving surface of the image-receiving material and add 1 ton of the following developing processing solution.
Both materials were passed through a conventional processor containing 300 ml and peeled 30 seconds after exiting the squeegee roller. Processing liquid temperature is 20℃
It is.

Diffusion Transfer Developer All of the comparative image-receiving materials had extremely unsightly images with a strong metallic luster on the surface, but only the image-receiving material of the present invention had a good image with a high maximum density and little surface gloss.

Example 2 Example 1 was repeated. However, the photosensitive material was placed on the same paper support as in Example 1, and carbon black for preventing haleyshiron, 1 f/d of catechol, and 0.3 tAt? A gelatin undercoat layer (gelatin 3 f/lp?) containing 1-phenyl-4-methyl-3-pyrazolidone is provided on top of which silver chloroiodobromide (8 molt of silver bromide, 1 molt of silver iodide) is applied. A gelatin silver halide emulsion layer (silver nitrate:gelatin=1:
4) and a protective layer (gelatin 1.3 f/m').

All of the comparative image-receiving materials formed silver images with sufficient gradation to reproduce the continuous tone original, but the images were significantly reddish brown over the entire density range. A silver image having a gradation similar to that of the comparative sample is formed on the image-receiving material of the present invention,
Moreover, the image had a good neutral gray tone.

Claims (1)

[Claims] An image-receiving element using a silver salt diffusion transfer method, characterized in that it contains a metal palladium colloid dispersion reduced with ascorbic acid in a hydrophilic colloid solution as a physical development core material.