JPS6147407B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver complex diffusion transfer method, and particularly to a silver halide photographic material used therein.

The principle of silver complex diffusion transfer method (hereinafter referred to as DTR method) is described in US Pat. No. 2,352,014 and is well known.

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 Exchange the silver halide with a soluble silver complex.

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 exchanged into 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 a direct positive silver halide emulsion, the effects of silver halide in exposed and unexposed areas are reversed.

It is well known that in order to produce a transferred silver image of high contrast and sharpness in the image-receiving layer, the transfer silver must be formed rapidly.

A common method for obtaining transferred silver images of even higher sharpness is to utilize an antihalation layer.

It is also well known that black pigments such as carbon black are preferably used in antihalation layers in silver halide photographic materials produced by the DTR method. This is because black pigments such as carbon black can absorb light in all wavelength ranges, and silver halide photographic materials using the DTR method do not need to be washed out or erased during processing.

However, although antihalation layers are effective for improving the sharpness and resolution of transferred silver images, they have the disadvantage of significantly lowering the photosensitivity.

Furthermore, it is extremely insufficient for image reproduction characteristics, that is, for reproducing 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, and especially It becomes difficult to faithfully reproduce any of the ruled lines of a document in which there are both positive image ruled lines (black lines) on a white background and negative image ruled lines (white lines) on a black background.

It is recognized that image reproducibility becomes extremely poor, especially when the photosensitive material has a photosensitivity to the extent that an original is photographed by a camera mark.

The reduction in photosensitivity due to the antihalation layer is
For example, as described in U.S. Pat. Although the image sharpness and resolution are good to some extent, the image reproduction characteristics are still unsatisfactory.

An object of the present invention is to provide a silver complex diffusion transfer material having high sensitivity, high sharpness, high resolution, and high image reproduction characteristics.

Another object of the present invention is to provide a silver complex diffusion transfer material suitable for camera work that has high image reproduction properties.

Still another object of the present invention is to provide an improved lithographic printing plate that has sufficiently high ink receptivity and printing durability even for transferred silver images with extremely fine ruled lines.

The above-mentioned objects of the present invention are to provide a silver complex salt diffusion method in which a silver halide emulsion layer containing a white inorganic pigment is provided on a support whose spectral reflectance in the sensitive wavelength range of the silver halide emulsion layer is permanently 25% or less. This was achieved by using a transfer material.

Supports containing black pigments such as carbon black that do not undergo decolorization or film removal even after treatment by the DTR method and have permanently low spectral reflectance are well known. You can refer to it. However, although a photographic material simply provided with a silver halide emulsion layer on this support improves sharpness and resolution, it not only has unsatisfactory image reproduction properties but also suffers from an extremely large loss in photosensitivity. In contrast, the aforementioned U.S. patent
Although the diffusion transfer materials disclosed in the specifications of No. 3629054 and No. 4144064 can reduce the loss of photosensitivity by providing a layer of titanium dioxide, they are also insufficient in sharpness, resolution, and especially image reproduction characteristics.

By providing a silver halide emulsion layer containing a light-transmitting, light-scattering white inorganic pigment, preferably titanium dioxide, on the above support, higher sensitivity, higher sharpness, and higher It has been found that a silver complex diffusion transfer material having high resolution and improved ruled line reproduction characteristics can be obtained even when developed by the DTR method.

Supports used in the practice of the present invention include plastic films such as cellulose acetate, cellulose acetate butyrate, polyethylene terephthalate, polystyrene, and polypropylene, and laminated films thereof, synthetic paper, baryta paper, and α-olefin polymers such as polyethylene. It can also be obtained by mixing coloring agents such as carbon black, pigments, and dyes into paper laminated with plastic film, or by undercoating a colloidal solution mixed with carbon black or other pigments. A layer coated as a layer or a back layer can also be used as a support, and in short, a support that can absorb about 75% or more of the light in the sensitive wavelength range that passes through the silver halide emulsion layer. That's fine. The spectral reflectance can be determined by a known method of measuring the value in the sensitive wavelength range of the silver halide emulsion layer using a self-recording spectrophotometer.

A preferred colorant is carbon black;
The support defined herein can be used within a range of about 0.1 g/m ² to about 5 g/m ² .

The spectral reflectance of the support is preferably 10% or less.

The layer containing carbon black is preferably adjacent to the silver halide agent layer containing white pigment.

The silver halide emulsion used in the practice of this invention contains a white inorganic pigment. A preferred white inorganic pigment is titanium dioxide. However, white pigments such as zinc oxide, calcium carbonate, and calcium sulfate can also be used.

Although the amount contained in the silver halide emulsion layer cannot be determined unconditionally depending on the type and size of the pigment, the amount of binder in the emulsion, the amount of silver halide coating, etc., the amount of white inorganic pigment contained in the silver halide emulsion layer is Ratio is a relatively important factor. From about 0.5 to about 20 grams, preferably from about 1 to about 10 grams, of white pigment is used per gram of silver halide, calculated as silver nitrate. The average particle size of white inorganic pigment is
A diameter of about 0.05 to about 5 microns is preferably used. The white pigment can be added at any time during the emulsion manufacturing process, but is usually added after ripening.

Hydrophilic binders that are advantageously used to prepare the light-sensitive emulsion in the silver halide photographic material of the present invention include lime-treated gelatin, acid-treated gelatin, gelatin derivatives (for example, Japanese Patent Publication No. 38-4854,
No. 39-5514, No. 12237-1223, No. 12237-
26345, U.S. Patent No. 2525753, U.S. Patent No. 2594293
No. 2614928, No. 2763639, No.
3118766, 3132945, 3186846, 3312553, British Patent No. 861414, British Patent No. 1033189
gelatin derivatives as described in the issue, etc.), albumin,
Proteins such as cezein, cellulose compounds such as carboxymethylcellulose and hydroxyethylcellulose, agar, natural polymers such as sodium alginate, polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylic acid copolymers, polyacrylamide or derivatives thereof, partially hydrated There are synthetic hydrophilic binders such as decomposition products,
These hydrophilic binders can be used alone or in combination. These hydrophilic binders are also advantageously used to make non-photosensitive layers such as antihalation layers, interlayers, protective layers (or release layers) or image receiving layers containing carbon black.

The amount of the binder in the silver halide emulsion layer is desirably at most 2 parts by weight, preferably up to 1.0 parts by weight, based on silver halide calculated as silver nitrate. Silver halide coverage is usually about 0.5 to about 5
g/m ² range.

The silver halide may be any one of silver chloride, silver bromide, silver chlorobromide, or a combination thereof with silver iodide. As mentioned above, in the present invention, a relatively large amount of white inorganic pigment is used relative to the amount of silver halide. The reason for this is that it compensates for the insufficient halation prevention effect, which cannot be perfect, in other words, the insufficient image reproduction characteristics due to the halation effect, and also improves the sharpness of the image in a state where silver halide grains are wrapped. It is inferred that That is, when looking at the cross-sectional structure of a silver halide emulsion layer, the distribution of halation light spreads over a longer distance in the lower layer of the emulsion (closer to the support). White pigments serve to reduce the amount of photographic light reaching the support, and at the same time the halation of the arriving light is extremely small. Silver halide grains having a large amount of white pigment particles surrounding them have a higher probability of being exposed to light as the grains are located higher in the emulsion layer, and due to the influence of the light-scattering white pigment, the particles spread farther in the upper layer of the emulsion.

Although it is considered that the sharpness, resolution, and image reproduction characteristics are improved as compared to the conventional ones based on the above reasoning, the present invention is not limited by the reasoning in any way. Therefore, when the negative ruled lines of the original are formed on the image receiving element after DTR processing, the width of the negative ruled lines becomes larger than the original line width, and the positive ruled lines become smaller than the original line width, so that the negative ruled lines and the positive ruled lines become different. The thinning and collapse of fine lines that occur when mixed characters (for example, complex kanji are one example) are greatly improved.

The use of a relatively large amount of white pigment relative to silver halide can significantly reduce the loss of sensitivity due to the support used in the present invention.

Because white pigments are relatively light transparent,
Although it is desirable to use the amounts mentioned, they should be avoided to such an extent that no light passes through the silver halide emulsion layer (this also depends on the sensitivity of the emulsion).

Yet another advantage of the present invention is that the efficient use of photographic light completely eliminates the diffusion of the exposed silver halide into the image receiving element, resulting in improved sharpness, resolution, and image reproduction characteristics due to increased contrast of the transferred silver image. This results in an increase in the amount of transferred silver (improvement in transfer density) in a prefogged direct positive silver halide emulsion.

Special Publications 16725-16725, 30562-30562, 51-
16803, as described in the specification of JP-A-53-21602
The present invention is particularly effective in planographic printing plates using the DTR method.

Silver halide emulsions can also be spectrally sensitized in blue, green, and red. It can be a merocyanine, cyanine dye or other sensitizing dye.

Furthermore, the silver halide emulsion can be chemically sensitized with various sensitizers, such as sulfur sensitizers (e.g. hypo, thiourea, labile sulfur-containing gelatin, etc.), noble metal sensitizers (e.g. Gold chloride, gold rhodan, ammonium chloroplatinate, silver nitrate, silver chloride, palladium salts, rhodium salts, iridium salts,
rutinium salts, etc.), polyalkylene polyamine compounds described in U.S. Patent No. 2,518,698, imino-amino-methanesulfinic acid described in German Patent No. 1,020,864, reduction sensitizers (e.g., stannous chloride, etc.), etc. are advantageous. used for.

The constituent elements of the silver halide photographic material of the present invention may further contain various additives.

For example, Holimarin, mucochloric acid, chromium alum, vinyl sulfone compounds, epoxy compounds,
Hardeners such as ethyleneimine compounds, mercapto compounds, antifoggants or stabilizers such as tetraazaindene, saponins as surfactants, sodium alkylbenzene sulfonates, sulfosuccinic acid ester salts, alkylaryls described in U.S. Pat. No. 2,600,831. In addition, anionic compounds such as sulfonates and amphoteric compounds as described in US Pat. Wetting agents such as N-guanyl hydrazone compounds, quaternary onium compounds, mordants such as tertiary amine compounds, diacetylcellulose, styrene-perfluoroalkylene sodium maleate copolymers, styrene-maleic anhydride copolymers and P-aminobenzenesulfonic acid, matting agents such as polymethacrylic acid esters, polystyrene, colloidal silicon oxide, film property improvers such as acrylic acid esters, and various latexes, Glycerin, gelatin plasticizer such as Japanese Patent Publication No. 43-4939, styrene-maleic acid copolymer,
Thickeners and antioxidants PH such as Special Publication No. 36-21574
Conditioners and the like can be used.

The processing liquid used in the diffusion transfer method contains alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium tertiary phosphate, etc., silver halide solvents such as sodium thiosulfate, ammonium thiothianate, and cyclic imide compounds. , thiosalicylic acid, etc., preservatives, such as sodium sulfite, thickening agents, such as hydroxyethyl cellulose, carboxymethyl cellulose, etc., antifoggants, such as potassium bromide, 1-phenyl-5-mercaptotetrazole, etc., developer modifiers. , such as polyoxyalkylene compounds, onium compounds, developing agents such as hydroquinone, 1-phenyl-
3-pyrazolidone and the like, alkanolamines and the like can be included.

However, in a highly alkaline processing solution containing this developing agent, the developing agent suffers from air oxidation and loses its effectiveness.
That is, it is known that these drawbacks can be largely avoided by incorporating it into a silver halide emulsion layer and/or a hydrophilic colloid layer having a water-permeable relationship therewith.

In diffusion transfer materials containing such a developing agent, an alkaline active liquid containing no or substantially no developing agent is usually used.

The DTR method using an alkaline activation solution was developed by Tokko Sho.
Reference may be made to specifications such as No. 39-27568, No. 47-30856, No. 43778 No. 51-Sho.

Next, Examples will be described to further specifically explain the present invention, but the present invention is not limited to these examples, and various applications can be made within the scope of the claims.

Example 1 Lithographic printing plate No. 3 in Example 1 of JP-A-53-21602 was prepared as described above. However, the undercoat layer was 1.0 g/m ² of carbon black and 3 g/m ² of gelatin, and the spectral reflectance of this support was 3%.

The silver halide emulsion layers used were those containing no titanium dioxide (comparison) and those containing 5 grams of titanium dioxide per 1.5 grams of silver halide (as silver nitrate) (invention).

A document containing both 60-micron negative ruled lines and positive ruled lines was photographed using a plate-making camera using the two types of lithographic printing plates mentioned above, and was then plate-made and printed according to the description of the above-mentioned patent specification.

The lithographic printing plate of the present invention had about twice the photosensitivity of the comparative lithographic printing plate.

Regarding the printed matter produced by both printing plates, the printed matter produced by the printing plate of the present invention had extremely small collapse and narrowing of ruled lines, whereas the printed matter produced by the comparative printing plate was unsatisfactory in terms of image reproduction characteristics.

Example 2 Instead of the silver halide emulsion used in Example 1,
Example 1 was repeated except that the direct positive silver halide emulsion described in the example of U.S. Pat. No. 4,144,064 was used. The results of the printed matter were the same as those of Example 1, and the printing plate of the present invention was also superior in the printing durability of the ruled lines.

Example 3 A polyethylene resin layer containing carbon black (spectral reflectance 7%) was coated with silver chloride having an average particle size of 0.3μ at a concentration of 1.0g/m ² in terms of nitrate on a laminated paper support. A silver halide emulsion (gelatin 0.7 g/m ² ) ortho-sensitized with a dye was coated (comparative sample).

1.0 g of titanium dioxide in the above silver halide emulsion
Four samples of the present invention were prepared in the same manner, containing 5 g/m ² , 3 g/m ² , 6 g/m ² and 9 g/m ² .

These samples were photographed as originals as in Example 1, brought into close contact with a conventional image-receiving material, passed through a conventional developing machine containing the following diffusion transfer developer, and peeled off in 60 seconds. (Processing temperature 20℃) Water 800ml Anhydrous sodium sulfite 40g Sodium tertiary phosphate (12H ₂ O) 75g Potassium hydroxide 5g Sodium thiosulfate (5H ₂ O) 20g Potassium bromide 1g 1-phenyl-5-mercapto-tetrazole
The total amount was adjusted to 1 with water. The transferred images obtained with the samples of the present invention had better image reproduction characteristics than those of the comparative samples, but especially titanium dioxide (3 g/m ² and 6 g/m 2 )
The one with ^m2 was good.

Claims (1)

[Claims] 1 Formation of a transfer silver image characterized by providing a silver halide emulsion layer containing a white inorganic pigment on a support whose spectral reflectance in the sensitive wavelength range of the silver halide emulsion layer is permanently 25% or less A silver complex diffusion transfer material combined either integrally or separately with an image-receiving element.