JPS6358342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a diffusion transfer method in which a photosensitive material and an image-receiving material are overlapped and processed.

The silver complex salt diffusion transfer method generally uses a photosensitive material in which a silver halide emulsion layer is formed on a support as a photosensitive layer, an image receiving material in which an image receiving layer containing physical development nuclei is formed on a support, and a silver halide emulsion layer as a photosensitive layer. Consists of a processing liquid containing a solvent. The principle of the silver complex diffusion transfer method is that the silver halide in the exposed area of the exposed photosensitive layer is developed by the developing agent in the processing solution or the photosensitive material, and at the same time, the silver halide in the final developed area is developed by the processing solution. It reacts with the silver halide solvent contained therein to form a soluble silver complex salt, which diffuses into the image-receiving material and deposits on physical development nuclei in the image-receiving layer to form a silver image.

In the silver complex diffusion transfer method based on this principle, there is a "mono-sheet" method in which the photosensitive layer and the image-receiving layer are formed on the same support, and a "mono-sheet" method in which the photosensitive layer and the image-receiving layer are formed on separate supports. When used, there is usually a "two-sheet" method in which these two materials are immersed in a processing solution, then overlapped and pressed together with a roller, and then peeled off after diffusion transfer. The present invention relates to the latter method.

The silver complex diffusion transfer method is used in the reproduction of documents, such as reproduction of technical drawings, printed matter or handwriting, and as a printing material in platemaking, and requires image reproduction faithful to the original manuscript.

In the case of the "two-sheet" diffusion transfer method, in order to uniformly diffuse the silver complex salt, it is necessary that the photosensitive layer of the photosensitive material and the image-receiving layer of the image-receiving material are in complete contact with each other. Usually, a developing device equipped with a processing liquid tank and a pressure roller is used to immerse a photosensitive material and an image-receiving material in a processing liquid, and then overlap the two and bring them into close contact with each other using a roller. In such processing, air bubbles in the processing solution adhere to the surface of the image-receiving layer or photosensitive layer, and are not completely submerged by the roller pressure, remaining between the photosensitive layer and the image-receiving layer, and the air bubbles are removed. It is known that the adhesion is incomplete or the processing liquid is missing, and the silver complex salt is not diffused and transferred, resulting in a thin dotted line-shaped transfer failure area on the image receiving layer.

In particular, photosensitive materials and image-receiving materials that use paper or film as a support are prone to creases, which causes air to be mixed in, resulting in the above-mentioned development problem. The thin, dotted line-like transfer defects appearing on the image-receiving layer significantly deteriorate the reproduction of diffusion-transferred images, such as letters and thin lines.

Conventionally, methods for eliminating this defective transfer area include gum arabic, alginic acid and its derivatives, dragant gum, cellulose derivatives (e.g. carboxymethyl cellulose, hydroxyethyl cellulose), starch derivatives, polyvinyl alcohol and its derivatives (e.g. partially saponified polyvinyl alcohol). ), polyacrylamide, polyacrylic acid, polyvinylpyrrolidone, maleic acid copolymer, and other water-soluble or alkali-soluble polymer substances are added to the processing solution to make it viscous.
15891. Furthermore, as a method for improving the releasability and adhesion of photosensitive materials and image-receiving materials,
Attempts are already known to replace part of the binder in the photosensitive layer of a photosensitive material and the image-receiving layer of an image-receiving material with the above-mentioned polymeric substances, or to use these polymeric substances in the uppermost layer of the photosensitive layer and the image-receiving layer. ing. These attempts were published in German Patent No. 869008 and British Patent No.
No. 748892 German Patent Publication No. 1055953, Special Publication No. 1973
-Described in Nos. 18134 and 18135.

However, although attempts using conventionally known polymeric substances are quite effective in eliminating transfer defects due to air inclusion, they are still far from perfect methods. In particular, when at least one constituent layer of the photosensitive material and the image-receiving material contains a fluorinated surfactant, even if the above-mentioned polymeric substances are used, the disadvantages of poor transfer as described above occur significantly. It was hot. It is known that fluorinated surfactants can be used as excellent coating aids or antistatic agents in the production of photographic materials, and a large number of their compounds have become known; Regardless, it is a serious problem that when used as a material in the silver complex diffusion transfer method, the drawback of poor transfer as described above occurs, and a solution to this problem is desired.

An object of the present invention is to provide a diffusion transfer method that does not cause transfer defects as described above.

Further objects of the invention can be understood from the following description.

One method for solving the above-mentioned transfer defects is a known method of preventing air (bubbles) from being mixed in, such as by using a polymeric substance. However, the present inventors have discovered that, contrary to expectations, a method of reducing the surface tension of diffusion transfer processing is extremely effective as another important method for solving the transfer defect. This is because the method of reducing the surface tension of the diffusion transfer processing solution contains a surface tension reducing agent, that is, a substance that causes bubble generation, which is clearly considered unfavorable to the known method of preventing bubble inclusion. However, the fact that the above-mentioned transfer defects can be completely prevented despite this fact makes it easy to understand the surprisingness and superiority of the effects of the present invention.

The present invention provides a diffusion transfer method in which a photosensitive material and an image-receiving material are superimposed and brought into close contact with each other, and after transfer processing is performed, both materials are peeled off. The surface tension of the treatment liquid is approximately 40 dynes/cm or less, preferably approximately
This is a diffusion transfer method characterized by a transfer rate of 35 dynes/cm or less.

Fluorinated surfactants are, for example,
9303, 1972-43130, JP-A-46-7781, 1977
-46733, Showa 49-133023, Showa 50-99529, Showa
50-113221, 1972-129229, 1972-111330,
Those described in US Patent No. 3589906, Belgian Patent No. 742680, etc. can be used. Although fluorinated surfactants can be used as extremely excellent coating aids, they have a common drawback in that they significantly cause poor transfer as described above. The fluorinated surfactant is contained in at least one of the hydrophilic binder layers constituting the photosensitive material and image-receiving material. When a fluorinated surfactant is contained at least in the surface layer, transfer defects are more likely to occur, and this is a particularly useful embodiment of the present invention.

The fluorinated surfactant used in the present invention is not limited to the compounds described in the above-mentioned patent specifications, but may also be other compounds. In general, groups that have three or more fluorine atoms and at least three carbon atoms bonded in the molecule and groups that impart appropriate hydrophilicity (e.g., carboxylic acid, sulfonic acid, sulfuric acid, phosphoric acid, Acid or a salt thereof, a hydroxy group, an oxyalkylene group, an onium group, a diester group, etc.) are preferred.

Some specific examples are shown below, but it goes without saying that the invention is not limited to these.

In order to incorporate the fluorinated surfactant used in the present invention into the hydrophilic binder solution, water or methanol,
It may be added as a solution in an organic solvent such as ethanol or acetone that is optionally miscible with water, and the amount added is about 0.01 to about 20 g, preferably about 20 g per 1 kg of binder solution.
A range of 0.05 to 10 g is suitable. It may be added at any time before coating on a support, etc., but when added to a silver halide emulsion, it is generally best to add at any time from after ripening until coating. The fluorinated surfactant can be used in either or both of the light-sensitive material and the image-receiving material, and can also be used in one or more hydrophilic binder layers. Furthermore, it can also be used in combination with non-fluorinated surfactants.

The diffusion transfer processing solution used in the present invention may contain conventional pharmaceutical ingredients, except that it preferably contains a substance capable of reducing its surface tension to about 35 dynes/cm or less. For example, alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, preservatives such as sodium sulfite, antifoggants such as potassium bromide, potassium iodide, silver halide solvents, e.g. Sodium thiosulfate, color toning agents such as 1-phenyl-5-mercaptotetrazole, development modifiers such as onium compounds, developing agents such as halodroquinone, 1-phenyl-3-pyrazolidone, the aforementioned polymeric substances, and other sequestering agents. , amine compounds, and the like.

The pH of the developer is the pH that activates the developing agent, usually around
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 types and amounts of various compounds used in the developer composition, processing conditions, etc.

The surface tension of a diffusion transfer processing solution containing conventional components is lower than that of water, but is usually around 45 dynes/cm. In the present invention, it is particularly preferable to set the surface tension to about 35 dynes/cm or less, but if there are few defects in transfer, even a surface tension in the range of about 40 dynes/cm to about 35 dynes/cm is acceptable. Defects can be improved.

A specific example of the surface tension reducing agent used in the diffusion transfer processing solution of the present invention is a fluorinated surfactant as described above. Other specific examples are surfactants as exemplified below.

(a) Sodium di(2-ethylhexyl) sulfosuccinate (b) Sodium hebutyl-α-sulfolaurate (c) Sodium hexyl-α-sulfoperargonate (d) Sodium octyl-α-sulfoperargonate (e) Sodium oleate (f) Sodium polyoxyethylene alkyl allyl ether sulfonate (g) 2-Butyloctylbenzene sulfonate (h) Nonadecane-10-sulfate (i) Hebutadecane-9-sulfate (j) Anhydro(dimethylstearyl-α-sulfonate) Propylammonium hydroxide) Furthermore, preferred compounds include JP-A No. 55-95947
It is an acetylene glycol listed in
This compound is particularly useful in the present invention because of its low foaming properties. A particularly preferred compound is represented by the following formula.

R ₁ to _{R 4} represent an alkyl group, and n+m=N represents the number of moles of ethylene oxide added, preferably 10
That's all. The exemplified surface tension reducing agents range from 0.1 to
It is a compound that can reduce the surface tension of a 1% by weight aqueous solution (20°C) to 30 dynes/cm or less. It is preferred to use a concentration range of about 0.005 to about 0.5% by weight in the diffusion transfer processing solution. If the concentration is too high, foaming will become significant, which is not desirable for preventing transfer defects.

As can be inferred from the above description, the above-mentioned disadvantages of poor transfer are not only caused by air bubbles, but are also due to the compatibility between the diffusion transfer processing liquid and the material rather than the cause of air bubbles. It is thought that the wettability of the bubbles is a major cause of poor transfer, but it is not known whether the wettability and air bubbles are independent causes. In any case, it will be understood that the present invention has clarified one concept and means for solving transfer defects.

In the present invention, it is preferable to use the hydrophilic polymer substances described above. However, for example, when processing with a processing solution containing carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, etc., or when processing using these substances as the top layer of the photosensitive layer and image-receiving layer, the The adhesion of the subsequent photosensitive material is poor, and both materials easily slip when touched lightly with the hand, and when peeled off, they tend to peel off partially. Therefore, when a polymeric substance is used in the surface layer of a material, it should be used as thinly as possible, for example, at a thickness of about 0.8 g/m ² or less, and when used in a processing liquid, it should be used in an amount such that the viscosity is about 20 centipoise or less. It is preferable to use it in

When carrying out the DTR method, as described in the specifications of British Patent Nos. 1000115, 1012476, 1093177, etc., a photosensitive silver halide emulsion layer and/or an image receiving layer, or It is common practice to incorporate a developing agent into another adjacent water-permeable colloid layer. Therefore, the processing solution used in the development step can be a so-called alkaline activating solution that does not contain a developing agent.

A general photosensitive material for the DTR method is composed of at least one silver halide emulsion layer provided on a support, and the silver halide content, calculated as silver nitrate, is generally in the range of 0.5 g to 3.5 g/ ^m2 . applied. In addition to this silver halide emulsion layer, if necessary, an undercoat layer,
Auxiliary layers such as intermediate layers, protective layers, and release layers are provided.

Silver halide emulsions consist of silver halides, such as silver chloride, silver bromide, silver chlorobromide, and their iodides, dispersed in hydrophilic colloids. Silver halide emulsions can be sensitized in a variety of ways when they are manufactured or coated. It may be chemically sensitized by methods well known in the art, for example with sodium thiosulfate, alkylthioureas, or with gold compounds such as rhodan gold, gold chloride, or a combination of both. good. The emulsion is about 530 more.
It is typically sensitized to the ~560 nm range, but may also be bank sensitized. The silver halide emulsion can also be a direct positive silver halide emulsion.

The silver halide emulsion layer and/or the image-receiving layer may contain any compound commonly used for carrying out the diffusion transfer method. These compounds can include, for example, fog suppressants such as tetrazaindene and mercapto compounds, hardeners such as formalin and chrome alum, and plasticizers. The support used for the photosensitive material or image-receiving material is any commonly used support. These include paper, glass, films such as cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film, etc., metal supports coated on both sides with paper, and paper supports coated on one or both sides with an α-olefin polymer such as polyethylene. You can also use your body. The image-receiving material contains physical development nuclei, such as heavy metals or their sulfides.

Examples will be described below, but it goes without saying that the invention is not limited to these examples.

Example 1 An image receiving layer consisting of a processed product of PVA containing palladium sulfide cores and ethylene/maleic anhydride copolymer was placed on a polyethylene-coated paper support at a dry weight of 3 g/
^m2 , and an image receiving material was prepared.

On the other hand, a gelatin undercoat layer containing carbon black, 1-phenyl-4-methyl-3-pyrazolidone, hydroquinone, etc. was provided on a polyethylene-coated paper support, and silver chlorobromide with an average particle size of 0.3μ was applied thereon. (Silver bromide 3 mol%) converted to silver nitrate is 1.5
A negative light-sensitive material was prepared by providing an ortho-sensitized silver halide emulsion layer containing g/m ² . The silver halide emulsion contained 1 g of exemplified compound (11) and 3 g of exemplified compound (h) per 1 kg of coating solution.

After exposing the photosensitive material to sensitometric light, it is processed using a conventional processor containing the following viscous developer for diffusion transfer (surface tension: 45 dyne/cm).
Both materials were peeled off 60 seconds after exiting the squeezing roller.
The processing temperature is 20°C.

Although a high-density, high-contrast image was obtained on the image-receiving layer, a large number of fine dotted line-shaped transfer defects continuously occurred in the blackened silver image area in the aperture direction of the roller.

[Transfer developer]

Water Trisodium phosphate (12 hydrate) 75 g Potassium hydroxide 10 g Anhydrous sodium sulfite 40 g Sodium thiosulfate (pentahydrate) 15 g Potassium bromide 1 g Methylaminoethanol 20 ml Hydroxyethyl cellulose 4 g 1-phenyl-5-mercaptotetrazole
The treatment was carried out in the same manner except that 0.1 g of the following compound was added to the treatment solution. The surface tension was 31 dynes/cm (20°C). High concentration on the image receiving layer,
A high-contrast image was obtained, and no transfer defects were observed in the image area.

Example 2 Example 1 was repeated. However, as fluorinated surfactants used in the emulsion layer of photosensitive materials, (2), (5), (8),
The experiment was conducted on five types of photosensitive materials using (10) or (14). The results of Example 1 were reproduced in all samples.

Example 3 CMC instead of hydroxyethyl cellulose,
Example 1 was followed except that sodium alginate, bullulan or dextrin were used. Similar results were obtained.

Example 4 Carbon black on the same paper support as in Example 1.
An antihalation layer consisting basically of 0.5 g/m ² and gelatin 3 g/m ² and a layer consisting essentially of titanium dioxide 10 g/m ² and gelatin 3 g/m ² on top of this antihalation layer using a slide hopper extrusion coating machine. Multilayer coating was performed. Next, a back layer was coated on the back side of the coated product so that the gelatin content was 8 g/m ² .

Further, on the layer containing titanium dioxide, a direct positive silver halide emulsion mainly composed of silver chloride and a gelatin protective layer were coated in layers to produce a photosensitive material. The exemplified compound (a) was used in the antihalation layer and the titanium dioxide layer, and the exemplified compound (a) and the exemplified compound (12) were used in combination in the emulsion layer and the protective layer, respectively.

Processing was carried out in the same manner as in Example 1 using the following diffusion transfer processing solution. Surface tension is 47 dynes/cm (20℃)
It was hot.

[Transfer developer]

Water 700ml Sodium sulfite (anhydrous) 50g Sodium hydroxide 12g Hydroquinone 8g 1-phenyl-3-pyrazolidone 1g Sodium thiosulfate (pentahydrate) 20g Potassium bromide 1g Potassium iodide 0.1g N-methyl-aminoethanol 10ml Hydroxyethyl cellulose Adjust to 1 with 2 g of water. Although a high-density, high-contrast image was obtained on the image-receiving layer, a significant number of dotted line-shaped transfer defects were generated in the transferred image area.

On the other hand, the acetylene glycol used in Example 1, exemplified compounds (5), (9), (12), (16),
(a) or (f) is added at a rate of 0.1% by weight each,
The same tests were carried out thereafter. Transfer defects were improved to such an extent that they were hardly noticeable, and there were no abnormalities in the transfer characteristics. All treatment solutions had a surface tension of 35 dynes/cm (20°C) or less.

Example 5 Example 1 was repeated except that the image-receiving layer of the image-receiving material also contained exemplified compound (11). Although more transfer defects occurred with the blank processing solution, the transfer defects were completely resolved by using the processing solution containing acetylene glycol.

Claims (1)

[Claims] 1. In the diffusion transfer method in which a photosensitive material and an image-receiving material are superimposed and brought into close contact with each other, and after a transfer process is performed, both materials are peeled off. A diffusion transfer method characterized by a surface tension of approximately 40 dynes/cm (20°C) or less.