JP2000250165A - Heat-developable photosensitive material and its manufacture, image forming method and heat-developing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the heat-developable photosensitive material high in sensitivity and low in fog and small in fluctuation of characteristics due to storage and superior in image stability and to provide the heat-developable photosensitive material and the image forming method and the heat-developing apparatus restrained from occurrence of scratches and damages and uneven development and superior in conveyability. SOLUTION: The heat-developable photosensitive material (a) contains a silver halide photosensitive emulsion and an organic silver salt and a silver ion reducing agent and a hydrophobic binder and further, a gelatin in an amount of 45-500 mg/m2 on a support, and (b) contains a silver halide photosensitive emulsion and an organic silver salt and a silver ion reducing agent and a hydrophobic binder and further, a wax.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a) a photothermographic material having low fog, high sensitivity and improved image storability after processing, a method for producing the same, and an image forming method using the same. The present invention relates to a photothermographic material, a method of processing a photothermographic material, and a photothermographic apparatus having excellent transportability during development processing.

[0002]

2. Description of the Related Art The photothermographic material according to the present invention is described, for example, in US Pat.
No. 2,904, No. 3,457,075, and D.C. "Dry Silver Photographic" by Morgan
Material) and the like. These are photothermographic materials containing a photosensitive silver halide emulsion, an organic silver salt, a reducing agent for silver ions and a hydrophobic binder on a support, wherein the silver halide is contained for imparting photosensitivity. I have. In this photosensitive material, a layer is formed by a binder which is softened by heat in order to form an image by causing physical dissolution development in the layer by heat, and an organic silver salt as a silver ion source and a photosensitive halide are formed in this layer. It is configured to contain silver, a reducing agent, and the like. When a photothermographic material having such a configuration is heated, silver halide exposed to light becomes a physical development nucleus, and an organic silver salt as a built-in silver ion source reacts with a reducing agent to develop the photothermographic material. Progresses,
Form an image. It is characterized in that development proceeds without the supply of reagents, water, etc. from the outside, and that no fixing is performed.

There are two methods for preparing silver halide: a method of preparing a dispersion of an organic silver salt and then mixing a halogen component to convert a part of the organic silver salt to produce silver halide on the organic silver salt. There is a method of preparing and mixing silver halide. Silver halide formed by the former method is called in-situ silver halide, and silver halide formed by the latter method is called ex-situ silver halide.

In situ silver halide is preferred because it has good contact with an organic silver salt and has good developability in a photothermographic material in which thermal development proceeds by physical dissolution development in a layer. However, in the case of in situ silver halide,
Since silver halide is generated by conversion from an organic silver salt, it is not suitable for a case where it is difficult to control the grain size of silver halide and a higher sensitivity is desired.

On the other hand, when a separately prepared silver halide is used, the conventional technique for forming silver halide in an aqueous gelatin solution can be used to control the grain size, sensitize, control reciprocity failure characteristics, etc., so that versatility is achieved. Yes and preferred.
However, in this case, the silver halide grains prepared in the aqueous gelatin solution need to be contained in a state in which the silver halide grains are sufficiently brought into contact with the organic silver salt dispersed in the hydrophobic organic binder.

If the content of water-soluble gelatin is high, gelatin causes layer separation in a hydrophobic binder used in a photothermographic material, typically a binder such as polyvinyl butyral, and covers silver halide. As a result, the phenomenon that silver halide as a development nucleus is covered with a hydrophilic polymer having no thermoplastic property such as gelatin may occur, and as a result, development becomes difficult to occur, and as a result, the image density is not reduced. cause.

Therefore, it is usually necessary to thoroughly remove gelatin by washing, mix it with an organic silver salt, and disperse the gelatin with the organic silver salt for a certain period of time in order to obtain sufficient contact. As another method, a method in which a silver halide emulsion is mixed at the time of preparing an organic silver salt and an organic silver salt is prepared in the presence of the silver halide emulsion is also used. As a result, a photothermographic material having good developability can be obtained without causing gelatin to aggregate in a hydrophobic binder and impairing contact with an organic silver salt. Also, after preparing a silver halide emulsion in an aqueous gelatin solution, the gelatin is hydrolyzed,
A method is also known in which gelatin is removed as much as possible by washing with water, and then mixed with an organic silver salt.

Therefore, from the viewpoint of contact with an organic silver salt, it has conventionally been preferable that gelatin, which is a hydrophilic polymer, is not mixed into a silver halide emulsion, and attention has been paid so far to reduce this. Therefore, attention has not been paid to the amount (although minute) of gelatin mixing in the photothermographic layer.

The present inventors have conducted a detailed study on the amount of gelatin contained in these photothermographic materials, and have found that the characteristics of the photosensitive material vary greatly depending on the amount of gelatin contained in the photosensitive material. The present invention has been found.

[0010] Regarding b), in the field of printing plate making and medical treatment, the waste liquid caused by the wet treatment of the image forming material has been a problem in terms of workability. From the viewpoint as well, there is a strong demand for reduction of the processing waste liquid. Therefore, silver halide photosensitive materials, which can form a photographic image by heat treatment as a photosensitive material capable of forming a high-resolution, clear black image, which can be efficiently exposed by a laser image setter or a laser imager, have received particular attention. I'm getting bathed. These are described, for example, in U.S. Pat. Nos. 3,152,904 and 3,45.
7,075 and D.C. Morgan and B.M.
"Thermally Processed Silver System" by Shelly
SilverSystems ", Imaging Processes and Materials (Imaging)
Processes and Materials)
Neblette Eighth Edition, Sturge
e), V.I. Walworth, A .;
Shepp, 2nd page, 1969, etc.

Such a photothermographic material contains a reducible silver source (for example, a non-photosensitive organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide), and a reducing agent in an organic binder matrix. It is contained in a dispersed state. The photothermographic material is stable at room temperature, but when heated to a high temperature after exposure, metallic silver is generated by a redox reaction between a reducible silver source (acting as an oxidizing agent) and a reducing agent.
Therefore, the development proceeds without supplying a developing solution or any other processing solution from the outside as in the conventional photosensitive material, and a high-quality silver image is formed.

Unlike conventional photosensitive materials, heat-developable photosensitive materials are processed by heat. For example, it is important to uniformly contact the photosensitive material with a heat developing device in order to obtain a uniform image. As an example of the heat developing machine, for example, a heat developing device that performs heating while conveying while uniformly contacting the rotating heat roller, or a rotating roller for conveyance,
As seen in a thermal developing device consisting of a fixed surface heater that is in close contact with and covers the photosensitive material (where the photosensitive material is conveyed), the photosensitive material is applied to the heater surface in order to conduct heat uniformly from the heater surface. Must be satisfied at the same time. For this purpose, the photosensitive material must be pressed against the drum while being transported so that heating can be performed uniformly.

That is, the photosensitive material does not come off from the thermal developing drum after thermal development and is not conveyed even if it is pressed too strongly for uniform contact, the surface of the photosensitive material is damaged by contact, or one of the binders of the photosensitive material is damaged. Foreign matter such as a portion adheres to the heating member of the heat developing machine, and when the subsequent photosensitive material is thermally developed, it enters as a foreign matter between the photosensitive material and the roller to cause uneven development. In particular, the edge portion of the photosensitive material is liable to generate foreign matters because the edge of the film is easily damaged during cutting, and this is a problem particularly when successively processing photosensitive materials having different sizes. Conversely, if the pressure is weak, the adhesion deteriorates and uniform heating is not possible, resulting in unevenness in the image, and conversely, the adhesion is too poor to be conveyed. Further, there is a disadvantage that the conveyance varies depending on the speed of conveyance and the size of the photosensitive material to be processed.

In view of the above, various measures have conventionally been taken for photothermographic materials. For example, it has been reported that a matting agent may be effectively disposed on the first surface layer in order to increase the adhesion. However, with this method alone, although the adhesiveness when pressed against the heat roller is improved, separation from the roller is poor, or a problem arises in transportability due to being bitten by a fixed hood. Also, the pressure of the pressure-sensitive material causes damage to the surface of the photosensitive material, causing peeling of the binder, and peeling off the edge of the cutting surface of the photosensitive material, causing foreign matter to adhere to the roller, and causing the photosensitive material to be thermally developed next. To cause uneven development. If the pressure of the contact is reduced to such an extent that there is no problem in conveyance, the adhesion deteriorates and development unevenness occurs. Also, since the transportability also depends on the size of the photosensitive material, the optimal conditions for one size are unsuitable conditions for another size. In addition, it was difficult to prevent a problem in transportability. Particularly, in the case of a photothermographic material, the binder is softened at the time of development, so that the material may be easily damaged. In particular, when the development time is set to a short time, the above requirement is urgent.

[0015]

The object of the present invention a) is to provide:
It is an object of the present invention to provide a photothermographic material having high sensitivity, low fog, little change in characteristics of the photosensitive material due to storage, and excellent image stability.

The present invention b) relates to a photothermographic material, an image forming method and a photothermographic apparatus which are excellent in transportability with improved unevenness in development due to damage of the material due to adhesion to a roller and generation of foreign matter during thermal development. To provide. It is another object of the present invention to provide a photothermographic material, a photothermographic method, and a photothermographic apparatus, which have a higher photothermographic speed.

[0017]

The above object of the present invention is achieved by the following means.

Regarding a): In a photothermographic material containing a photosensitive silver halide emulsion, an organic silver salt, a reducing agent of silver ion and a hydrophobic binder on a support, gelatin is contained in an amount of 45 mg / m ^{2 to} 500 mg / m ^2.
mg / m ² .

2. 2. The photothermographic material according to the above item 1, wherein the gelatin content of the photosensitive silver halide emulsion is in the range of 5 g to 200 g per mol of silver halide.

3. Preparation of a silver halide emulsion comprising a mixing step of mixing a silver salt aqueous solution and a halide aqueous solution in a gelatin aqueous solution and a desalting step of the photosensitive silver halide emulsion contained in the photothermographic material according to 1 or 2 above. A method for producing a photothermographic material, which is prepared in a process.

4. The amount of gelatin contained in the aqueous gelatin solution used in the mixing step was adjusted for the amount of silver halide 1
(3) The weight of the above (3) is from 5 g to 1 kg per mole.
3. The method for producing a photothermographic material according to item 1.

5. In the desalting step, the gelatin content of the silver halide emulsion is adjusted to 5 g to 20 g per mole of silver halide.
5. The method for producing a photothermographic material according to the above item 3 or 4, wherein the amount is reduced to a range of 0 g.

6. Wherein the aqueous gelatin solution used in the mixing step contains an amino-blocked gelatin, and the pH of the desalting step is set to 5.1 or less.
Or the method for producing a photothermographic material according to item 5.

[7] 6. The photothermographic material according to item 3, 4 or 5, wherein the aqueous gelatin solution used in the mixing step contains low molecular weight gelatin having a molecular weight of 30,000 or less, and the desalting step is performed by ultrafiltration. Production method.

8. 3. A method for processing a photothermographic material, wherein the photothermographic material according to 1 or 2 is thermally developed at a temperature of 80 ° C to 140 ° C.

9. 3. An image forming method, wherein an image is obtained by exposing the photothermographic material according to 1 or 2 to infrared light and thermally developing the photothermographic material at a temperature of 80 ° C to 140 ° C.

10. After exposing the photothermographic material according to the above 1 or 2 with a laser beam, a processing temperature of 80 ° C. to 140 ° C.
An image forming method, wherein an image is obtained by heat development at a temperature of ° C.

11. 11. The image forming method according to the above item 10, wherein the exposure by the laser beam does not become substantially perpendicular to the photosensitive material.

Regarding b), A photosensitive silver halide emulsion, an organic silver salt,
A photothermographic material comprising a silver ion reducing agent, a hydrophobic binder and a wax.

13. 2. The photothermographic material according to item 1, wherein the outermost layer contains wax as viewed from the support.

14. 14. An image forming method, comprising thermally developing the photothermographic material according to the above item 12 or 13 at a temperature of 80 ° C to 140 ° C.

15. 14. The photothermographic material for developing a photothermographic material according to the above item 12 or 13, wherein a surface of a heating member of the photothermographic device in contact with the photothermographic material is made of silicon rubber. Heat development device.

Hereinafter, the present invention will be described in detail with respect to a).

The method for preparing the photographic emulsion used in the present invention is described in Chimie by Glafkids
et Physique Photographiqu
e (Paul Montel, 1967);
F. Photographic Em by Duffin
ulsion Chemistry (The Foca
l Press, 1966); L. Zelik
Making and Coat by man et al
ing Photographic Emulsion
(The Focal Press, 1964) and the like, and the silver halide emulsion of the present invention can be similarly prepared using these methods. That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and a method of reacting a soluble silver salt with a soluble halide may be any one of a one-sided mixing method, a double-sided mixing method, a combination thereof and the like. Good. Typically, a silver halide emulsion is prepared by mixing an aqueous solution of a silver salt and an aqueous solution of a halide in a protective colloid (in which gelatin is used) to perform nucleation and growth, but adding an aqueous solution of a halide or an aqueous solution of a silver salt. As a method, a double jet method is generally used. Among these, the controlled double jet method of mixing the components while controlling pAg and pH to perform the nucleation and nucleus growth is representative. In addition, various variations such as a method of preparing seed particles (nucleation) and then performing this growth in two steps of continuously performing the growth under the same conditions or different conditions (nucleus growth or ripening) are also included. I have. In short, it is well known in the art that the crystal habit and size are variously controlled by defining the mixing conditions of the silver salt aqueous solution and the halide aqueous solution in the mixing step in the protective colloid aqueous solution. Following these mixing steps, a desalting step of removing excess salts from the prepared emulsion is performed. As a desalting step, a flocculation method is used in which a flocculant is added to the prepared silver halide emulsion to coagulate and precipitate silver halide grains together with gelatin as a protective colloid, and this is separated from a supernatant containing salts. well known. The supernatant is removed by decantation, and further, dissolution, flocculation, and decantation are repeated in order to remove excess salts contained in the gelatin coagulated product containing the aggregated and precipitated silver halide particles. A method for removing soluble salts by ultrafiltration is also well known. As will be described later, by using an ultrafiltration membrane, a method of removing unnecessary salts having a low molecular weight by using a synthetic membrane that does not transmit large particles such as silver halide particles and gelatin and molecules having a large molecular weight is used. is there. The method of controlling the amount of gelatin in the silver halide emulsion in the present invention may be any method, but by devising the protective colloid used in the above mixing step and desalting step, the flocculation method used in the desalting step and It is achieved by making good use of ultrafiltration.

In the present invention, in order for the photothermographic material to exhibit preferable characteristics, the amount of gelatin should be 3 per m ² of the photographic material.
0 mg / m ² to 500 mg and preferably in the range of / m ^2, more preferably ^{45mg / m 2 ~300mg / m 2} , more preferably from 55~200mg / m ^2. This is in the range of 5 g to 200 g per mol of silver when converted to the gelatin content in the silver halide emulsion, and preferably 1 g per mol of silver.
The amount is from 0 to 150 g, more preferably from 10 to 100 g, and most preferably from 25 to 70 g.

In order to obtain the photothermographic material of the present invention, it is necessary to set the amount of gelatin contained in the silver halide emulsion within the above range. If the amount of gelatin in the silver halide emulsion can be controlled within this range, the present invention can be achieved by mixing this emulsion with an organic silver salt to form a photothermographic material. However, it is usually difficult to reduce the amount of gelatin as a protective colloid during the preparation of a silver halide emulsion when controlling the silver halide to produce it in a controlled manner. This is because the amount of protective colloid is also an important controlling factor for the crystal habit, size, size distribution and the like of silver halide. Therefore, a preferred method of doing this is to use a silver halide emulsion in which the conditions of the mixing step are not changed, ie, the amount of gelatin is usually 1 mol of silver halide, which is required in the mixing step of silver halide. Silver halide grains are prepared in an amount of 5 g to 1 kg per grain, and after the grains are prepared, the amount of gelatin is reduced in the desalting step to fall within the above range.
That is, up to about 800 g of gelatin per mole of silver halide needs to be removed by the above method in the desalting step. It is important not to have too much or too little.

In the present invention, the following two methods can be typically used to control the amount of gelatin in the desalting step.

One is to use an amino-blocked gelatin as the gelatin used in the mixing step of mixing the silver salt solution and the halide solution, and the other is to use a low molecular weight gelatin. Amino group-blocked gelatin is one in which the amino group is derivatized, for example, by phthalation or phenylcarbamoylation.Normal gelatin contains both an amino group and a carboxyl group, exhibits amphoteric properties, and exhibits isoelectricity. Although the solubility in water is poor near the point, the solubility is improved in both the alkaline and acidic regions, whereas the amino group-blocked gelatin is a gelatin having no solubility in the acidic region.

In order to obtain the photothermographic material of the present invention from a silver halide emulsion, the amount of gelatin used in the preparation of the silver halide is preferably from 5 g to 200 g per mole of silver in the silver halide emulsion in the desalting step. You need to lose weight in between. With this amount, the gelatin content in the photothermographic material can be controlled within the above range, and the preferable effects of the present invention can be obtained.

In the preparation of the silver halide emulsion, the amount of the gelatin used in the mixing step was from 5 g per mol of silver.
To reduce the weight to a value of up to 200 g, it is preferred to remove the gelatin in the desalting step during the manufacturing process.

When amino group-blocked gelatin is used, the pH value of the silver halide emulsion during flocculation in the desalting step is controlled to control the amount of precipitated amino group-blocked gelatin. I just need. The lower the pH, the greater the amount of amino-blocked gelatin that precipitates with the silver halide grains. That is, a large amount of amino group-blocked gelatin remains in the silver halide emulsion. On the other hand, if the pH value is high, the amount of precipitated amino group-blocking gelatin decreases, and the amount of amino group-blocking gelatin contained in the silver halide emulsion decreases. Alternatively, the gelatin may be considerably removed once in the desalting step, and the required amount may be added to adjust the amount of gelatin.

However, most preferably, a silver halide emulsion is prepared by using both normal gelatin and amino group-blocked gelatin, and sedimentation and washing are carried out in an acidic region in a desalting step, whereby ordinary silver halide emulsions are prepared. While gelatin can be removed by washing, amino-blocked gelatin precipitates without solubility and can be left behind, so it is necessary to control the amount of gelatin contained in silver halide by changing this ratio. It is. Thereby, the amount of gelatin in the emulsion can be set within the above-mentioned range of the present invention. How much pH
Whether precipitation should be performed at a specific value varies depending on the type of gelatin used, the degree of amino group blocking, and the like, and cannot be unambiguously determined. However, in the present invention, the pH value is usually 5.1 in the present invention.
It is preferable to perform the desalting step below. Therefore, in the case of the present invention, it is important to keep the pH of the silver halide emulsion at 5.1 or less. Especially during the desalting step, the pH is 4.9.
When it is maintained at -4.1, favorable stiffening occurs and an emulsion with low fog is obtained.

The desalting step referred to herein is to remove the silver halide emulsion formed in the presence of the protective colloid from the silver halide emulsion by adding a flocculant to the silver halide emulsion. Refers to a process from the point of time of addition to the completion of removal of the supernatant containing soluble salts and the like after one or several times of coagulation and sedimentation.

An acid is generally used for pH adjustment, and organic acids such as acetic acid, citric acid and salicylic acid, hydrochloric acid, nitric acid, and the like are used.
Inorganic acids such as sulfuric acid and phosphoric acid are preferably used, and among them, acetic acid and citric acid are particularly preferable because they cause favorable setting. Further, in the present invention, in the desalting step, an aggregated polymer agent may be used in combination. in this case,
It is important to keep the temperature of the silver halide emulsion above 50 ° C. Particularly, when the temperature is maintained at 53 to 75 ° C., preferable stiffening can be performed.

As the amino group-blocked gelatin used in the present invention, a derivatized gelatin in which an amino group is substituted with a substituent so that solubility is reduced in an acidic region is preferred. The method for producing gelatin itself is not particularly limited as described below, and examples thereof include those which can be produced by ordinary and well-known methods. Examples of the substituent for the amino group of gelatin are described in U.S. Pat. Nos. 2,691,582, 2,614,928 and 2,525,753.

Useful substituents for obtaining a modified gelatin by substituting an amino group include (1) acetyl and
Acyl groups such as unsubstituted benzoyl; (2) carbamoyl groups such as alkylcarbamoyl and arylcarbamoyl;
(3) sulfonyl groups such as alkylsulfonyl and arylsulfonyl, (4) thiocarbamoyl groups such as alkylthiocarbamoyl and arylthiocarbamoyl, (5) straight-chain and branched alkyl groups having 1 to 18 carbon atoms, and (6) substitution And unsubstituted phenyl, naphthyl and aryl groups such as aromatic heterocycles such as pyridyl and furyl. Among them, a preferred modified gelatin is an acyl group (—COR ₁₁ )
Or a carbamoyl group (—CONR ₁₁ R ₁₂ ).

R ₁₁ is a substituted or unsubstituted aliphatic group (for example, an alkyl group having 1 to 18 carbon atoms, an allyl group), an aryl group or an aralkyl group (for example, a phenethyl group); Group, an aryl group, or an aralkyl group. Particularly preferred is a case where R ₁₁ is an aryl group and R ₁₂ is a hydrogen atom.

Hereinafter, specific examples of the amino group-blocked gelatin which can be used in the present invention will be described with reference to amino group substituents, but the present invention is not limited thereto.

[0049]

Embedded image

When an amino group-blocked gelatin is used for removing (desalting) dissolved substances, the amount of addition is not particularly limited, but 0.1% of the substance (preferably gelatin) contained as a protective colloid at the time of removal is used. A quantity of from 5 to 5 times (weight) is generally suitable, particularly preferably from 0.3 to 2 times (weight).

In the same manner, low molecular weight gelatin is used in the mixing step consisting of nucleation and growth of silver halide emulsion, and ultrafiltration operation described below is performed after grain formation to convert low molecular weight gelatin. A silver halide emulsion having a small amount of gelatin can be obtained by partially or almost completely removing the emulsion. In practice, the amount of low molecular weight gelatin itself is controlled by controlling the time of ultrafiltration, and in the preparation of silver halide emulsion, only low molecular weight gelatin is used by mixing with normal gelatin. There are two ways to control the amount of gelatin in the silver halide emulsion by removing it by filtration.

As the low molecular gelatin, gelatin having a molecular weight of 30,000 or less is preferably used. The step of mixing the silver salt aqueous solution and the halide solution (nucleation and nucleus growth) using these low molecular weight gelatins instead of ordinary gelatins is performed, and in the desalting step, the low molecular weight gelatins are converted to soluble salts by ultrafiltration. The gelatin can be reduced as described above by the method of removing together. That is, it is preferable to use an aqueous solution containing gelatin having a molecular weight of 30,000 or less during nucleation and growth. The content of gelatin at the time of nucleation and growth is preferably 1.6% by weight or more based on the reaction mother liquor. As the kind of gelatin, alkali-treated gelatin is usually used, but other acid-treated gelatin, ion-exchanged gelatin, and gelatin made from fish can also be used.

The molecular weight distribution and average molecular weight of gelatin can be measured by a general method, for example, gel filtration chromatography.

The molecular weight of gelatin can be controlled by a generally known method such as hydrolysis with acid or alkali, enzymatic decomposition, coacervation method, and cleavage of cross-linking by ultrasonic irradiation. In the enzymatic digestion, a specific binding position of a gelatin molecular chain is cleaved, so that a low-molecular-weight gelatin having a relatively narrow molecular weight distribution can be obtained, and the average molecular weight can be adjusted by the enzymatic digestion time. Is preferred. For enzymatic degradation,
R. J. Cox; Photographic Gela
tin II, Academic Press, London
on, 1976, pp. 233-251, 335-346.
Page for the coacervation method, Pourad
ir; Chem. Phys. 47 volumes, 391 pages, 4
The method described in Vol. 9, page 85 can be referred to.

Other general methods for producing photographic gelatin used in the present invention are described in, for example, The Photographic Society of Japan, "Basics of Photographic Engineering, Silver Salt Photography" (Corona), pp. 122-124;・ Macromolecular Chemistry of Gelatin (Academic Press, 19
64, etc.).

In the case of the gelatin according to the present invention, the gelatin may be lime-treated or acid-treated, and the gelatin according to the present invention may be deionized with an ion-exchange resin or the like. The gelatin according to the present invention may be oxidized with hydrogen peroxide or another oxidizing agent. When the oxidation treatment is performed by adding hydrogen peroxide, the amount of hydrogen peroxide added is 25 g / kg. os or more, more preferably 50 g / kg. os or more.

The gelatin contained in the emulsion of the present invention preferably has a gold value of 20 μmol u / g gelatin or less, more preferably 15 μmol u / g gelatin or less, further preferably 8 μmol u / g gelatin. It is as follows.

To determine the gold value, the gelatin is subjected to an electrometer titration with tetrachloroauric acid at pH 2. Gold consumption gives gold value. Non-oxidized gelatin shows ≧ 23 μmol u / g by this method, which is substantially ≧ 5
This corresponds to a methionine content of 0 μmol u / g.

In the present invention, when low molecular weight gelatin is used, desalting is preferably performed by ultrafiltration, and at the same time, low molecular weight gelatin is removed to leave a desired amount of gelatin. When the silver halide grains are fine grains, the smaller the grain size, the easier it is to agglomerate, and the more likely it is for uneven development during development to occur.In the present invention, desalting is also performed simultaneously by ultrafiltration, It is preferable to prevent aggregation of the fine particles.

The ultrafiltration according to the present invention will be described.
The term "ultrafiltration" is described in M.E. Cheyan, Ultra
Filtration Handbook "(Technomic Publishing Co., 1986). In this filtration method, a membrane is generally used, and the membrane allows unnecessary substances to pass through. For example, in the purification of a colloidal silver dispersion, a purification method using a membrane that allows unnecessary salts and the like to pass therethrough without passing through a necessary substance such as colloidal silver.

In this selective separation, the solution is hydraulically pressed against a synthetic semipermeable membrane formed so that all particles smaller than a specific size are selectively passed, and larger particles are retained. Performed by

Ultrafiltration membranes are permeable to only molecules of a certain size or smaller and contain pores sized to retain larger molecules and silver halide grains in the dispersion. Ultrafiltration is preferably carried out by circulating the dispersion in the reaction vessel while in contact with the outer semipermeable ultrafiltration membrane so that a pressure difference is created across the semipermeable ultrafiltration membrane. . In general, the membrane is permeable to only molecules of a certain size or smaller and contains pores sized to retain larger molecules and silver halide grains in the dispersion. Suitable membranes are preferably about 500 to 300,0
00 or more, more preferably about 500 to 5
It can be selected from those exhibiting transmission cutoff characteristics in the molecular weight range of 000.

In practicing the present invention, the cut-off molecular weight can be easily varied outside this range. It will be readily appreciated that this cut-off molecular weight should generally not be greater than the molecular weight for the protective colloid. In general,
The choice of a particular transmission cut-off molecular weight depends on the silver halide particle size at the beginning of ultrafiltration and the small molecular weight material (retenta) that may be retained in the emulsion.
te)).

[0064] The pressure of the emulsion in contact with the ultrafiltration membrane may be varied over a wide range. Typically, for the practice of the present invention, the pressure in the reaction vessel that contacts the ultrafiltration membrane is preferably between about 100 psi and 500 psi, typically about 100 psi (7.03 kg / cm ² ). Yes,
The outlet pressure of the retentate is preferably between about 5 psi and 10 p
si or less, typically about 10 psi (0.703 kg
/ Cm ² ) or less. The pressure differential across the membrane is typically about 40-60 psi (2.81-4.22 kg / c).
m ² ). Of course, rubbing can be arbitrarily set by those skilled in the art according to the structure of the reaction vessel and the ultrafiltration membrane, the viscosity of the emulsion, the concentration of the retentate, and the desired purity of the retentate.

That is, the silver halide and excess salts suspended in the protective colloid in the container are removed by known means.
It is pumped through a flow meter into an ultrafiltration module, the excess salts being withdrawn as filtrate, while the residues recirculate into the vessel during a recycle operation mode.

In another approach, a number of ultrafiltration modes can be connected in series so that the residue from the previous module is fed into the next module's inlet line.

Prior to subsequent flow of the liquid through each module, the liquid can be rediluted with a solvent for desalting and washing purposes, or, alternatively, the solvent can be diluted for concentration purposes. No need to re-dilute.

When performing concentration and desalting by ultrafiltration, the temperature is preferably 60 ° C. or lower, more preferably 20 ° C. or higher and 50 ° C. or lower.
It is below ° C.

When concentration and desalting are carried out by ultrafiltration, the time required from the start to the end of concentration / desalting is a total of 2 times.
It is preferably 10 minutes or less, more preferably 190 minutes or less. At this time, a filtrate containing excess salts is taken out, and the drainage rate is preferably 15 cc / min or more, more preferably 17 cc / min or more, and further preferably 20 cc / min or more per 1 mol of silver.

The amount of the emulsion used for concentration and desalting by ultrafiltration is 5 to 2,000 mol, preferably 100 to 1,000 mol, in terms of silver.

The membrane used for ultrafiltration is typically an anisotropic membrane comprising very thin walls of a very fine porous structure supported on a thicker porous structure. Useful membranes are
Various polymer substances, for example, polyvinyl chloride, polyvinyl carboxylate, polyvinyl formate, polyvinyl acetate, polyvinyl alcohol, polysulfone, polyvinyl ether, polyacrylamide, polyimide, polyester,
Polyfluoroalkylene (eg, polytetrafluoroethylene), and polyvinylidene fluoride, and any cellulosic polymer such as cellulose and cellulose esters such as cellulose acetate, cellulose butyrate, and cellulose acetate butyrate. Can be something.

The effect of the present invention can be achieved by controlling the amount of gelatin contained in the photothermographic material of the present invention by any of these methods. We have:
With the intention of improving the contact between the organic silver salt and the silver halide and improving the developability, when performing an experiment excluding gelatin in the prepared silver halide emulsion, if the amount of gelatin is reduced too much, the deterioration of photographic properties may be worse. I found something to be brought.

[0073] In the present invention, as for the photothermographic material exhibits a desirable characteristics mentioned above, a preferred range of the photosensitive material 1 m ² per 30mg / m ² ~500mg / m ² as the amount of gelatin, more preferably Is 45 mg / m ^{2 to} 300
mg / m ^2, more preferably from 55~200mg / m ^2. This is in the range of 5 g to 200 g per mole of silver, preferably 10 to 150 g, more preferably 10 to 150 g, in terms of gelatin content in the silver halide emulsion.
100 g, most preferably 25-70 g.

It is not clear why such a phenomenon occurs with a minute change in the amount of gelatin. If you think normally, gelatin will adsorb on the surface of silver halide,
If the amount is too large, gelatin will be taken into the silver halide in the thermoplastic binder, which is a place for the solution physical development, and will be aggregated, so that the physical development activity of the exposed silver halide will not be reduced. The sensitivity and low gamma are considered to be sufficient, and when the amount of gelatin is small, the silver halide and the organic silver salt are in sufficient contact to increase the development activity of the silver halide. It was expected that a photothermographic material having a high density, a high gamma and a high density would be obtained. However, contrary to the expectation in the range of a small amount of gelatin as in the present invention, when the amount of gelatin contained in the photothermographic material is too small, high fog, low sensitivity, low gamma, and It was found that the preservability of the image after processing was poor, and that a photosensitive material having high sensitivity, low fog, and good preservation of the image could be obtained by increasing the amount of gelatin. However, if the amount of gelatin exceeds the preferable range and is increased too much, fog increases, and raw preservability deteriorates at low γ. It was surprising to the present inventors that the optimal amount of gelatin exists and that the photographic properties are influenced by these.

According to a preferred method, the emulsion prepared as described above is mixed with a solution of an organic acid alkali so that the emulsion is maintained in effective contact with the organic silver salt. Is used in the process of preparing an organic silver salt. Thereby, lower fog and higher sensitivity can be obtained as compared with the conventional one.

The amount of gelatin contained in the light-sensitive material can be controlled both in terms of calculation and practically by adjusting the amount of gelatin contained in the silver halide emulsion in advance as described above. As shown below, it can be separately measured and confirmed.

The gelatin content in the light-sensitive material was determined as follows. "The film punched out exactly 40 cm ² was finely cut into pieces of about 5 mm × 5 mm, put into a 5 ml hydrolysis tube, added with 5 ml of 6N hydrochloric acid, cooled with dry ice + methanol, and completely frozen. After degassing and sealing, the mixture was put into a thermostat at 110 ° C. for 24 hours to carry out hydrolysis, and then the decomposed solution was concentrated and absolutely dried.
It was dissolved in 5 ml of a pH = 2.0 citrate buffer solution. The measuring device used was a JLC-300 fully automatic high-speed amino acid analyzer manufactured by JEOL Ltd., and the detection method was 440n by the ninhydrin method.
m, absorption at 570 nm was measured. Column is 6mmi
d × 90 mm (strongly acidic cation exchange resin), column length 6.0φ × 90 mm, buffer pump flow rate 0.72 m
1 / min, ninhydrin pump flow rate 0.36 ml / m
in, column temperature initial setting is 54 ° C, 65 minutes after 15 minutes
° C, and measured at a reaction tank temperature of 120 ° C.

In the measurement, ossein gelatin was hydrolyzed in advance, and the same measurement was carried out using a reference solution having a concentration of 0.5 g / ml. The spectrum obtained was converted to the amount of gelatin using the peak areas of glycine and alanine. Then, a calibration curve is prepared, and the amount of gelatin is calculated from the peak area of the sample using the calibration curve. The silver halide particles function as an optical sensor. In a photothermographic material, the average particle size is preferably smaller in order to suppress white turbidity after image formation and to obtain good image quality. Preferably, the average value of the diameter in terms of a straight sphere is preferably from 0.0001 μm to 0.1 μm, more preferably from 0.001 μm to 0.1 μm, even more preferably from 0.001 μm to 0.08 μm. Further, the particle ratio of 0.1 μm or more is 15
%, Preferably 10% or less, more preferably 5% or less.

The straight-ball-equivalent diameter referred to here is defined in J. Org.
F. Hamilton, Photo. Sci. En
g. , 11 (1967), 57; Shiozaw
a. Sci. Photo. Sci. Japan, 35
(1972) 213, that is, observation and photographing were performed using a transmission electron microscope at a low temperature, and a projection image of the particles was obtained by the method described in US Pat. No. 4,434,226.
The diameter when converted to a circular image of the same area was measured, and the average value was obtained for all the measured particles.

In the size distribution of the silver halide grains of the present invention, the coefficient of variation of the sphere-converted diameter (the standard deviation of the diameter divided by the average diameter) is preferably 30% or less, more preferably 20% or less. , More preferably 15% or less, and most preferably 10% or less.

When the silver halide grains are cubic or octahedral so-called normal crystals, the grain size refers to the length of the edge of the silver halide grains. In the case of non-normal crystals, for example, in the case of spherical, rod-shaped or tabular grains, it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is not particularly limited, but the ratio occupied by the Miller index [100] plane is preferably high, and this ratio is 50% or more, and more preferably 7% or more.
It is preferably at least 0%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by T.M. using the dependence of adsorption of the photosensitive dye on the [111] plane and the [100] plane. Tani, J .; Imaging Sci. , 29,
165 (1985).

Another preferred form of silver halide is tabular grains. The term “tabular grain” as used herein means a thickness hμ in the vertical direction, where the square root of the projected area is a particle size rμm.
It means that the aspect ratio = r / h when m is 3 or more. Among them, the aspect ratio is preferably 3 or more and 50 or more.
It is as follows. The particle size is preferably 0.1 μm or less, and more preferably 0.01 μm to 0.08 μm. These are disclosed in U.S. Pat. Nos. 5,264,337;
No. 314,798, No. 5,320,958, and the like, and the desired tabular grains can be easily obtained. When these tabular grains are used in the present invention,
Further, the sharpness of the image is improved. The halogen composition of the silver halide grains is preferably silver bromide, silver iodobromide or silver chloroiodobromide. The silver iodide content is preferably from 0.01 mol% to 10 mol%, more preferably from 0.1 mol% to 5 mol%. The particles may be core / shell particles having different halogen compositions in the core layer and the shell layer. The halogen composition in the grains is
It can be examined by an X-ray diffraction method, a composition analysis method using EPMA, or the like.

The photographic emulsion used in the present invention can be prepared by the above-mentioned method. The silver halide may be added to the image forming layer by any method, in which case the silver halide is arranged close to the reducible silver source. Further, the silver halide may be prepared by converting a part or all of the silver in the organic acid silver by the reaction of the organic acid silver and the halogen ion into silver halide, or may be prepared by preparing silver halide in advance. In advance, this may be added to a solution for preparing an organic silver salt, or a combination of these methods is possible, but the latter is preferred. Generally, the silver halide is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.

The silver halide used in the present invention preferably contains ions of a transition metal belonging to Group 6 to Group 10 of the periodic table for the purpose of improving illuminance failure and adjusting the improvement. As the above metals, W, Fe, Co, Ni,
Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, A
u is preferred, and these metal ions may be introduced into silver halide in the form of a metal complex or complex ion, although a metal salt may be directly introduced into silver halide. As these transfer metal complexes and metal complex ions, hexacoordinate complex ions represented by the following general formula are preferable.

In the formula [ML ₆ ] ^m , M is a transition metal selected from the elements of Groups 6 to 10 of the periodic table, L is a bridging ligand, and m is 0,-, 2-, 3- or Represents 4-. Specific examples of the ligand represented by L include:
Halides (fluoride, chloride, bromide and iodide),
Examples include cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide, and aquo ligands, nitrosyl, thionitrosyl, and the like, and preferably aquo, nitrosyl, and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Specific examples of particularly preferred M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

The following are specific examples of the transition metal coordination complex ion.

[0089] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2-11 : [Re (NO) Cl ₅ ] ^2-12 : [Re (NO) (CN) ₅ ] ^2-13 : [Re (NO) Cl (CN) ₄ ] ^2-14 : [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) (CN) _5] ^2- 17: [Fe (CN) _6] ^3- 18 : [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN ^2- 23: [Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir ( NO) Cl _5] ^2- 27: [Ir (NS) Cl _5] ^2- 28: [IrCl _6] ^2- these metal complexes or complex ions may be one type,
Two or more metals of the same type and different types of metals may be used in combination.

The content of these metal ions, metal complexes and complex ions is generally from 1 × 10 ^-9 to 1 × 10 ^-2 mol per mol of silver halide, preferably from 1 × 10 ^-9 to 1 × 10 ^-2 mol. X 10 ^-8 to 1 X 10 ^-4 mol. Compounds that provide these metal ions or complex ions are preferably added during silver halide grain formation and incorporated into silver halide grains, and preparation of silver halide grains,
That is, it may be added at any stage before and after nucleation, growth, physical ripening, and chemical sensitization, but it is particularly preferable to add at the stage of nucleation, growth, and physical ripening. It is preferably added at the stage of nucleation. In the addition, it may be added in several divided portions, may be uniformly contained in the silver halide grains, or may be added to JP-A-63-29603, JP-A-2-306236, and JP-A-2-306236. No. 167545, 4-
No. 76534, No. 6-110146, No. 5-2736
As described in JP-A-83, etc., the particles can be contained in the particles with a distribution. These metal compounds may be water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides).
, For example, an aqueous solution of a powder of a metal compound or a metal compound and NaCl, KCl
A method in which an aqueous solution obtained by dissolving the silver halide solution and the silver salt solution is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or added as a third aqueous solution when the silver salt solution and the halide solution are simultaneously mixed. A method of preparing silver halide grains by a three-liquid simultaneous mixing method, a method of charging a required amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, or a method of preparing metal ions or complex ions in advance when preparing silver halide. A method of adding another silver halide grain doped with and dissolving it. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution. When adding to the particle surface, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

The photosensitive silver halide grains in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods include sulfur sensitization, selenium sensitization, tellurium sensitization, noble metal sensitization such as gold compounds, platinum, palladium, and iridium compounds, and reduction sensitization, as is well known in the art. Sensitization can be used. Known compounds can be used as compounds preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method.
Compounds described in No. 8768 and the like can be used.
Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, and British Patent 618,061
And the like. Specific compounds of the reduction sensitization method include, as well as ascorbic acid, thiourea dioxide, for example, stannous chloride,
Aminoiminomethanesulfinic acid, hydrazine derivatives,
Borane compounds, silane compounds, polyamine compounds and the like can be used. When the pH of the emulsion is 7 or more or p
Reduction sensitization can be achieved by ripening while keeping Ag at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

Hereinafter, the present invention b) will be described in detail.

When a photothermographic material is used, a high-quality image can be obtained by simple processing. However, it is necessary to heat the photothermographic material uniformly during heat development. Contact is important, and it is particularly important to solve the above-mentioned problems. The present invention is intended to solve the above-mentioned problems by including the above-mentioned compound in a surface layer of a photothermographic material. is there.

By incorporating the wax of the present invention into the photothermographic material, the photothermographic material can be brought into close contact with the heating member and the uniform heat transfer can be achieved. Facilitates peeling.

The above effects are maximized by incorporating these compounds in the uppermost layer of the photothermographic layer. In addition, since defective transport due to uneven transport is improved, the generation of film fragments and other foreign substances caused by the rubbing of the heating drum and the surface of the photosensitive material is reduced, and these foreign substances are removed from the drum and the photosensitive material. Heating unevenness or the like due to being sandwiched therebetween is reduced. In particular, foreign matter from the cutting section or the like is likely to be generated at the edge portion of the photosensitive material, so that the generation of such foreign matter that is likely to occur when processing photosensitive materials of different sizes can be reduced. The effect is particularly large when the processing speed of the photothermographic material is high. The photothermographic layer in the photothermographic material is a binder softening by heating, for example, usually a protective layer for using a polymer such as polyvinyl butyral, and a binder constituting the outermost layer such as a back coat layer has a softening point. Higher polymers are selected, and those which are less likely to be deformed or peeled off even when they come into contact with each member of a heat developing machine, such as a drum or a roller, which is in contact during continuous thermal development processing. As representatives thereof, cellulose acetate, cellulose acetate butyrate and the like are preferably used, but the compound does not cause excessive bleeding even when contained in these binders, and can exhibit a stable effect. it can. Compounds of the present invention are also useful in this aspect, since those having an excessively large effect on the heat development characteristics are not preferred.

As the wax used in the present invention, any wax generally used can be used. Specific compounds include beeswax, candelilla wax, paraffin wax, ester wax and montan wax. And solid waxes such as carnauba wax, amide wax, polyethylene wax and microcrystalline wax. In the present invention, silicone oil is another example having an effect similar to the above wax.

The amount of the wax to be added is preferably 0.001 to 20 g / m ² , more preferably 0.01 to 1.
0 g / m ^2, particularly preferably from 0.05 to 0.5 g / m ^2. As the amount is increased up to a certain amount, the damage of the photosensitive material is reduced, but the material is devitrified. On the other hand, if the amount is too large, the generation of shavings due to abrasion increases on the contrary. However, if the amount is too small, the effect of the invention is not exhibited. The effect of accelerated thermal development is more pronounced as the amount is increased. Taking these into consideration, an appropriate amount can be easily found experimentally within a preferable range of the addition amount.

The place of addition is preferably a contact surface with a heating roller for thermal development, and a protective layer, a back coat layer and the like are preferred. However, even if it is added to another layer, a similar effect can be obtained due to effects such as diffusion. Further, even if it is added to the layer on the surface opposite to the contact surface with the heating roller, an effect closer to the transfer between rollers can be obtained.

The added wax and lubricant are attached to the heating roller, but are attached to the film surface and taken out, so that a certain equilibrium state may be formed.

In order to remove the attached wax, the heating roller is preferably provided with a scraping member by a blade or a removing member by transfer.

As the heat developing machine used in the present invention, any type can be used. In short, any material can be used as long as the photosensitive material can be brought into close contact with the heat source and the photothermographic material can be uniformly heated. The adhesion and peeling of the heat source material to the surface is the essence of the present invention and does not depend on the form of the heat developing machine. A typical example of the thermal developing device is a device having a heat drum which can bring a photosensitive material into close contact with the drum and uniformly heat the photosensitive material. Also, any material that can continuously process the photosensitive material may be used. For this purpose, a heat developing machine of a type in which a heat drum is movable and conveys a photosensitive material by rotation is preferable. Typical examples of these are Tokiohei 1
Japanese Patent Application Laid-Open No. 0-500977 discloses an example.

FIG. 1 is a schematic view showing a preferred embodiment of the thermal developing apparatus according to the present invention, but the present invention is not limited thereto.

As shown in FIG. 1, the heat developing apparatus comprises a movable heating member 1 which is movable, a guide member 2 for introducing and transporting the photosensitive material smoothly, and a processor frame 3 for fixing the same. . Processor frame 3
Is a pair of processor end member 4 and guide member bracket 5
It has. The heated shaft 6 of the heating member 1 protrudes from both ends of the heating member 1, and is rotatably provided by a shaft bearing 7 provided on the end member 4. The heating member 1 is rotated from a motor (not shown) via a belt drive device 9 by a belt 8 suspended on the shaft. As shown in FIG. 2, a plurality of guide members 2 are provided so as to surround the cylindrical heating member 1 and in a direction parallel to the heating member 1. Mounted in an elongated opening 12, the guide member 2 is free to rotate, and is engaged by a spring 10 to uniformly press the photosensitive material against the heating member. . The strength of the spring can be changed so that the photosensitive material can be smoothly transported. The photothermographic material is represented by S,
The heat enters the thermal developing device from this direction. Although not shown, these heating units are configured so as to be entirely covered with a heat insulating casing.

FIG. 2 shows the side of the photosensitive material being conveyed around the heating member 1 and the guide member 2, and the guide plate X for peeling off the film from the introduction port A of the photothermographic material. It is provided about 220 degrees to a certain point. The photothermographic material S is carried in by the heating member 1 rotating from the introduction port A, is conveyed between the heating member 1 and the plurality of guide members 2 installed in equilibrium with the heating member 1, and is subjected to uniform heating and is thermally developed. , Peeling guide plate X
At a certain position, the thermal development is completed.
The peeling guide plate X is provided so as to guide the leading end of the photosensitive material from the heating member. The coefficient of friction between the heating member 1 and the photothermographic material S is sufficiently large so that when the leading edge of the photothermographic material S enters through the inlet and is caught by the first guide member, it can be transported reliably. It is set as follows. Further, the photothermographic material is held in a state of being pressed against the heating member 1 by the guide member 2, whereby the heating member 1 transmits sufficient heat to develop the photothermographic material S. I have. FIG. 3 is a cross-sectional view of the heat developing apparatus shown in FIG. The heating member is an aluminum tube 21 and a heater blanket 22 therein.
In FIG. 3, a flexible layer 23 of silicon rubber is provided on the surface of aluminum. An electronic control unit (not shown) for controlling the heating is connected to the heater blanket 22. The thickness of the flexible layer is preferably between 0.25 mm and 1.5 mm. If it is too thick, it will hinder the transfer of heat from the aluminum tube, and if it is too thin, it will be difficult to suppress image defects due to foreign matter and the like, and performance such as abrasion resistance will deteriorate. Further, it is preferable that the variation of the film thickness is not more than 10%, and if there is a variation of more than 10%, heat transfer becomes non-uniform, which causes uneven development.

Although the heating member 1 illustrated in FIGS. 1, 2 and 3 is shown as a rotatable cylindrical drum, the aluminum tube 21 constituting the heating member has a length of about 4 mm.
5cm, material thickness is 0.64cm, outer diameter is about 1
6 cm, which can be arbitrarily selected in consideration of the size of the thermal developing device, the processing ability, and the like. The variation in the thickness of the material of the aluminum tube is preferably kept within 4% in order to avoid uneven heating. It is necessary to select a width of the heating member having a width enough to convey the photothermographic material sufficiently. As the heating member that comes into contact with the photosensitive material, it is preferable to use a metal having good heat conductivity, and usually an aluminum tube is used. Aluminum is a preferable material having good thermal conductivity. It is preferable that the surface of the metal drum is uniformly coated with a flexible material so as not to damage the surface of the photosensitive material, and that the surface of the metal drum is coated with a polymer material having high heat conductivity and high heat resistance and flexibility. Is preferred. When the flexible layer is provided on the surface of the heating member, the thickness of the flexible layer is preferably between 0.25 mm and 1.5 mm. Those having a sufficient thermal conductivity are preferred. In addition to the above objects, these flexible layers preferably have a suitable coefficient of friction with the photosensitive material and do not hinder conveyance, and preferably have good peelability from the photosensitive material surface.

As the material of the flexible layer, silicone rubber is a more effective combination for ensuring good adhesion and releasability when processing the photothermographic material containing the wax of the present invention. Make things. Since the silicon-based material has a relatively low thermal conductivity, a material containing a dopant is preferably used in order to increase the thermal conductivity. Silicon rubber is a synthetic rubber whose main chain is composed of an organosiloxane bond, and the basic one is polydimethylsiloxane obtained from dimethyldichlorosilane as a raw material by dehydration condensation of silanol. Furthermore, in order to facilitate cross-linking and vulcanization, heat resistance and chemical resistance have been improved by introducing vinyl silicone rubber in which a part of methyl groups have been changed to vinyl groups, and further introducing phenyl groups and alkyl fluoride groups. There are phenyl silicon rubber and fluorinated silicon rubber, and these materials are preferable.
Further, those containing a dopant for increasing the thermal conductivity are also preferable.

Hereinafter, other constitutions and constitutional components of the photothermographic material used in the inventions a) and b) will be described, but are not necessarily limited thereto.

As the silver halide, the silver halide described in the above invention a) can be applied to the invention b).
The amount of these silver halides is 50% or less, preferably 25% to 0.1%, and more preferably 15% in the photothermographic material based on the total amount of silver halide and the organic silver salt described below.
〜0.1%. If the amount is too small, the number of developing points is insufficient, and the density is low, so that it is unusable. If it is too large, the photothermographic layer devitrifies.

In the present invention, the light-sensitive silver halide used in the photothermographic material is also disclosed in British Patent No. 1,44.
As described in US Pat. No. 7,454,749, when preparing an organic silver salt, a halogen component such as a halide ion is allowed to coexist with an organic silver salt forming component, and silver ions are injected into the component to form an organic silver salt. It can be generated almost simultaneously with the generation.

In the case of the present invention b), as another method,
A part of the organic silver salt can also be converted to photosensitive silver halide by applying a silver halide forming component to a previously prepared solution or dispersion of the organic silver salt or a sheet material containing the organic silver salt. . The silver halide thus formed is in effective contact with the organic silver salt and exhibits a preferable action. A silver halide-forming component is a compound capable of forming a photosensitive silver halide by reacting with an organic silver salt, and which compound is applicable and effective is determined by the following simple test. I can do things. That is, an organic silver salt is mixed with a compound to be tested, and if necessary, after heating, it is examined by an X-ray diffraction method whether there is a peak specific to silver halide. Silver halide-forming components confirmed to be effective by such tests include inorganic halide compounds, onium halides, halogenated hydrocarbons,
There are N-halogen compounds and other halogen-containing compounds, and specific examples thereof are described in U.S. Pat. No. 4,009,03.
No. 9, No. 3,457,075, No. 4,003,7
No. 49, British Patent No. 1,498,956, and JP-A-53-27027 and JP-A-53-25420, examples of which are shown below.

[0111] (1) inorganic halide: halide (wherein M represented by e.g. MX _n, H, NH _4, and represents a metal atom, n represents 1 when the M is H and NH _4, M
When is a metal atom, it represents the same value as its valence. Examples of the metal atom include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, tin, antimony, chromium, manganese, iron, cobalt, nickel, rhodium, and cerium. ). Further, halogen molecules such as bromine water are also effective.

(2) Onium halides: quaternary ammonium halides such as, for example, trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide, and quaternary phosphonium halides such as tetraethylphosphonium bromide And tertiary sulfonium halides such as trimethylsulfonium iodide.

(3) Halogenated hydrocarbons: for example, iodoform, bromoform, carbon tetrachloride, 2-bromo-2-methylpropane and the like.

(4) N-halogen compounds: For example, N-chlorosuccinimide, N-bromosuccinimide, N-bromophthalimide, N-bromoacetamide, N-iodosuccinimide, N-bromophthalazinone, N-bromooxazolinone, N-chlorophthalazinone, N-bromoacetanilide, N, N-dibromobenzenesulfonamide, N-bromo-N-methylbenzenesulfonamide,
1,3-dibromo-4,4-dimethylhydantoin, N
-Bromourazole and the like.

(5) Other halogen-containing compounds: for example, triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone and the like.

These silver halide forming components are used in a small amount stoichiometrically with respect to the organic silver salt. Usually, the range is from 0.001 mol to 0.7 mol, preferably from 0.03 mol to 0.5 mol, per 1 mol of the organic silver salt. Two or more silver halide forming components may be used in combination within the above range. Various conditions such as reaction temperature, reaction time, reaction pressure and the like in the step of converting a part of the organic silver salt to silver halide using the above-mentioned silver halide forming component can be appropriately set according to the purpose of production. Usually, the reaction temperature is -20 ° C to 70 ° C, the reaction time is 0.1 second to 72 hours,
The reaction pressure is preferably set at atmospheric pressure. This reaction is also preferably performed in the presence of a polymer used as a binder described below. The amount of the polymer used at this time is 0.01 to 100 parts by weight, preferably 0.1 to 10 parts by weight per 1 part by weight of the organic silver salt.

These silver halide forming components may be used in combination with a separately prepared silver halide emulsion or, for example,
In the present invention a), in addition to the silver halide emulsion prepared according to the present invention, the photothermographic material may contain silver halide formed by the above-mentioned silver halide forming component.

The photosensitive silver halide prepared by the various methods described above includes, for example, sulfur-containing compounds, gold compounds,
Platinum compounds, palladium compounds, silver compounds, tin compounds,
Chemical sensitization can be achieved by a chromium compound or a combination thereof. The method and procedure of this chemical sensitization are described in, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850, JP-A-51-224.
No. 30, No. 51-78319, and No. 51-81124. Also, when a part of the organic silver salt is converted to a photosensitive silver halide by a silver halide forming component, as described in US Pat. No. 3,980,482, sensitization is achieved. A low molecular weight amide compound may coexist.

Further, these photosensitive silver halides include metals belonging to groups 6 to 10 of the periodic table of elements, for example, Rh, Ru, R
It may contain ions such as e, Ir, Os, and Fe, and complexes or complex ions thereof.

In the present invention, the organic silver salt is a reducible silver source, and is a silver salt of an organic acid or a heteroorganic acid, especially a long-chain (10 to 30 carbon atoms, preferably 15 to 25 carbon atoms).
Silver salts of aliphatic carboxylic acids and nitrogen-containing heterocyclic compounds are preferred. Organic or inorganic complexes in which the ligand has a value of 4.0 to 10.0 as the total stability constant for silver ions are also preferred. Examples of these suitable silver salts include Rese
arch Disclosure (hereinafter abbreviated as RD) 1
7029 and 29996, and include the following.

Silver salts of organic acids, for example, gallic acid, oxalic acid,
Silver salts such as behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Silver carboxyalkylthiourea salts, for example, silver salts such as 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, and aldehydes with hydroxy-substituted aromatic carboxylic acids Silver salts or complexes of polymer reaction products, for example, silver salts of reaction products of aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted acids (for example, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid) Or complexes, silver salts or complexes of thiones, for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione, and 3-carboxymethyl-4-thiazoline-2
Silver salts or complexes such as -thione, imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,2;
Complexes or salts of silver and a nitrogen acid selected from 4-triazole and benzotriazole, silver salts such as saccharin and 5-chlorosalicylaldoxime, and silver salts of mercaptides. Among them, preferred silver salts include silver behenate, silver arachidate and silver stearate.

The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and includes a normal mixing method, a reverse mixing method, a simultaneous mixing method, and a method disclosed in JP-A-9-12764.
A controlled double jet method as described in No. 3 is preferably used. For example, an organic acid alkali metal salt soap (eg, sodium hydroxide, potassium hydroxide, etc.)
After preparing sodium behenate, sodium arachidate, etc., the above-mentioned soap and silver nitrate are mixed by a controlled double jet method to produce an organic silver salt crystal. At that time, silver halide grains may be mixed.

In the present invention, the organic silver salt has an average particle size of 1
It is preferably 0 μm or less and monodispersed.
The average particle size of the organic silver salt refers to the diameter of a sphere equivalent to the volume of the organic silver salt particles when the particles of the organic silver salt are, for example, spherical, rod-shaped, or tabular particles. Average particle size is 0.05 μm to 10 μm, preferably 0.05 μm
To 5 μm, particularly preferably 0.05 μm to 1.0 μm.
The monodispersion has the same meaning as that of silver halide, and preferably has a monodispersity of 1 to 30.

In the present invention, the organic silver salt preferably has tabular grains containing at least 60% of the total organic silver.
In the present invention, the tabular grains mean those having an aspect ratio (abbreviated as AR) of 3 or more, which is a ratio between the average particle diameter and the thickness, that is, the following formula.

AR = average particle size (μm) / thickness (μm) In order to form the organic silver salt into these shapes, the organic silver salt crystals are dispersed and pulverized with a binder, a surfactant and the like using a ball mill or the like. Obtained by: Within this range, a photosensitive material having a high density and excellent image storability can be obtained.

In the present invention, in order to prevent devitrification of the light-sensitive material, the total amount of silver halide and organic silver salt is preferably from 0.5 g to 2.2 g per m ² in terms of silver. . With this range, a high-contrast image can be obtained.

Examples of the reducing agent used in the photothermographic material of the present invention include generally known reducing agents, such as phenols, polyphenols having two or more phenol groups, naphthols and bisnaphthols. , 2
Polyhydroxybenzenes having at least two hydroxyl groups, 2
Polyhydroxynaphthalenes having at least two hydroxyl groups,
Ascorbic acids, 3-pyrazolidones, pyrazoline-
5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone monoethers,
Hydroxamic acids, hydrazides, amide oximes, N-hydroxyureas and the like are described in more detail. For example, U.S. Pat. Nos. 3,615,533 and 3,673
9,426, 3,672,904, 3,7
No. 51,252, No. 3,782,949, No. 3,
Nos. 801,321, 3,794,488, 3,893,863, 3,887,376, 3,770,448, 3,819,382,
No. 3,773,512 and No. 3,839,048
No. 3,887,378, No. 4,009,03
9, No. 4,021,240, British Patent No. 1,48
No. 6,148 or Belgian Patent No. 786,086 and JP-A-50-36143 and JP-A-50-36.
No. 110, No. 50-116023, No. 50-9971
No. 9, No. 50-140113, No. 51-51933
Nos. 51-23721, 52-84727 and JP-B-51-35851, and the present invention is appropriately selected from such known reducing agents. Can be used. As a selection method, the simplest method is to actually prepare a photothermographic material and evaluate the photographic performance to determine the superiority of the reducing agent used.

Among the above reducing agents, when an aliphatic silver carboxylate is used as the organic silver salt, preferred reducing agents include polyphenols in which two or more phenol groups are linked by an alkylene group or sulfur. In particular, an alkyl group (eg, methyl group, ethyl group, propyl group, t-butyl group, cyclohexyl group, etc.) or an acyl group (eg, acetyl group, propionyl group, etc.) is provided at at least one of the positions adjacent to the hydroxy substitution position of the phenol group. Is a polyphenol in which two or more of the phenol residues substituted by an alkylene group or sulfur, for example, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,
5,5-trimethylhexane, 1,1-bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-3,5-di-tert-)
Butylphenyl) methane, 2-hydroxy-3-t-butyl-5-methylphenyl)-(2-hydroxy-5-
Methylphenyl) methane, 6,6'-benzylidene-bis (2,4-di-t-butylphenol), 6,6'-
Benzylidene-bis (2-t-butyl-4-methylphenol), 6,6'-benzylidene-bis (2,4-dimethylphenol), 1,1-bis (2-hydroxy-
3,5-dimethylphenyl) -2-methylpropane,
1,1,5,5-tetrakis (2-hydroxy-3,5
-Dimethylphenyl) -2,4-ethylpentane, 2,
2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5
U.S. Pat. Nos. 3,589,903 and 4,021,249 or British Patent 1,486,148 and JP-A-51-51933. No. 50-36110, No. 50
Polyphenol compounds described in JP-A-116023, JP-A-52-84727 or JP-B-51-35727), and bisnaphthols described in U.S. Pat. No. 3,672,904, for example, 2,2 '-Dihydroxy-1,1'-binaphthyl,6,6'-dibromo-
2,2'-dihydroxy-1,1'-binaphthyl, 6,
6'-dinitro-2,2'-dihydroxy-1,1'-
Binaphthyl, bis (2-hydroxy-1-naphthyl) methane, 4,4'-dimethoxy-1,1'-dihydroxy-2,2'-binaphthyl and the like, furthermore U.S. Pat. No. 3,80
1,321, sulfonamidophenols or sulfonamidonaphthols, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4
-Benzenesulfonamidophenol, 4-benzenesulfonamidonaphthol and the like.

The amount of the reducing agent used in the photothermographic material of the present invention varies depending on the type of the organic silver salt, the reducing agent, and other additives. 05 mol to 10 mol, preferably 0.1 mol to 3 mol
Molar is appropriate. Further, within this range, two or more of the above-mentioned reducing agents may be used in combination. In the present invention, it may be preferable to add and mix the reducing agent to the photosensitive solution immediately before coating and apply the reduced solution because the photographic performance fluctuation due to the stagnation time of the photosensitive solution is small.

The photothermographic material of the present invention forms a photographic image by a heat development process. The photothermographic material of the present invention comprises a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, silver. It is preferable that the photothermographic material contains a color toning agent which suppresses the color tone of the present invention in a state of being usually dispersed in an (organic) binder matrix. The photothermographic material of the present invention is stable at room temperature, but is exposed to a high temperature (for example, 80 ° C to 14 ° C).
(0 ° C.). Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

Examples of suitable toning agents used in the present invention are R
D17029 discloses the following.

Imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and , 4-thiazolidinedione); naphthalimides (e.g., N-hydroxy-1,8-naphthalimide); cobalt complexes (e.g., hexaamminetrifluoroacetate of cobalt); mercaptans (e.g., 3-mercapto-1,2,2,3). 4-triazole); N
-(Aminomethyl) aryldicarboximides (eg, N- (dimethylaminomethyl) phthalimide);
Blocked pyrazoles (eg, N, N′-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole)); isothiuronium
onium) derivatives and certain photobleaches (eg, 1,8- (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2
-(Tribromomethylsulfonyl) benzothiazole combination); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-
Dimethyloxyphthalazinone and 2,3-dihydro-
1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone and sodium benzenesulfinate or 8-methylphthalazinone and sodium p-trisulfonate); a mixture of phthalazine and phthalic acid Combinations; phthalazine (including phthalazine adducts) and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivative and its anhydrides (e.g., phthalic acid, 4-methylphthalic acid, -Nitrophthalic acid and tetrachlorophthalic anhydride); quinazolinediones, benzoxazine, naphthoxazine derivatives; benzoxazine-2,4
-Diones (for example, 1,3-benzoxazine-2,
4-dione); pyrimidines and asymmetric triazines (eg, 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2, 3a, 5, 6
a-tetraazapentalene). Preferred toning agents are phthalazinone or phthalazine.

The photothermographic materials of the present invention include, for example, JP-A Nos. 63-159841, 60-140335, 63-231437, 63-259651, and 6
3-304242, 63-15245, U.S. Pat. Nos. 4,639,414 and 4,740,455,
Nos. 4,741,966 and 4,751,175
No. 4,835,096. Useful sensitizing dyes for use in the present invention are described, for example, in RD17643 IV-A (p.2 December 1978, p.2).
3), Item 18431X (August 1979, p. 437)
Or cited in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources such as a laser can be advantageously selected. For example, JP-A-9-34078 and JP-A-9-5
Compounds described in Nos. 4409 and 9-80679 are preferably used.

In the present invention, a matting agent is preferably contained on the photosensitive layer side, and a matting agent is preferably provided on the surface of the photosensitive material in order to prevent the image after thermal development from being damaged. Is preferably contained in a weight ratio of 0.5 to 30% based on all binders on the photosensitive layer side.

When a non-photosensitive layer is provided on the opposite side of the photosensitive layer with the support interposed therebetween, it is preferable that at least one layer on the non-photosensitive layer side contains a matting agent, so that the light-sensitive material has slipperiness and fingerprint adhesion. For prevention, it is preferable to provide a matting agent on the surface of the photosensitive material, and the matting agent is used in a weight ratio of 0.5 to 4 with respect to all binders in the layer on the side opposite to the photosensitive layer side.
It is preferable to contain 0%.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance. For example, as inorganic substances, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkali described in British Patent No. 1,173,181 etc. An earth metal or a carbonate such as cadmium or zinc can be used as a matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037, Belgian Patent No. 625,451 and British Patent No. 981,198.
And polyvinyl alcohol described in JP-B-44-3643 and the like, and Swiss Patent No. 33.
No. 0,158, polystyrene or polymethacrylate; U.S. Pat. No. 3,079,257; polyacrylonitrile; U.S. Pat. No. 3,022,16.
An organic matting agent such as polycarbonate described in No. 9 or the like can be used.

The shape of the matting agent may be either regular or irregular, but is preferably regular and spherical. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent preferably has a variation coefficient of the particle size distribution of 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the coefficient of variation of the particle size distribution is a value represented by the following equation.

(Standard deviation of particle size) / (average value of particle size) × 100 These matting agents can be contained in any constituent layer, but are preferably photosensitive to achieve the object of the present invention. It is a constituent layer other than the layer, more preferably the outermost layer as viewed from the support.

The method for adding the matting agent according to the present invention may be a method in which the matting agent is dispersed in a coating solution in advance and applied.
A method of spraying a matting agent after the application liquid is applied and before the drying is completed may be used. When a plurality of types of matting agents are added, both methods may be used in combination.

The photothermographic material of the present invention may contain an antifoggant. Mercury compounds known from, for example, U.S. Pat. No. 3,589,903 as effective antifoggants are environmentally undesirable. For this reason, non-mercury antifoggants have been studied for a long time. Non-mercury antifoggants include, for example, U.S. Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-5723.
No. 4 is preferred.

Particularly preferred non-mercury antifoggants are described in US Pat. Nos. 3,874,946 and 4,756,99.
No.9, -C (X ₁ )
(X ₂ ) A heterocyclic compound having one or more substituents represented by (X ₃ ) (where X ₁ and X ₂ are halogen and X ₃ is hydrogen or halogen). Examples of suitable antifoggants include JP-A-9-288328, paragraph [0030].
To [0036] are preferably used.

Examples of another preferred antifoggant include JP-A-9-90550, paragraph [006].
2] to [0063]. Further, other suitable antifoggants are disclosed in US Pat.
No. 28,523 and European Patent Nos. 600,587, 605,981 and 631,176.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, to improve storage stability before and after development, and the like. be able to.

In addition to these materials, various additives may be added to a photosensitive layer, a non-photosensitive layer, or other forming layers according to the purpose. The photothermographic material of the invention may contain, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, a coating aid, and the like. These additives and the other additives described above are also the same as those described in the aforementioned RD17.
029 (p. 9-15, June 1978) can be preferably used.

The binder suitable for the photothermographic material of the present invention is transparent or translucent and generally colorless, and includes natural polymers, synthetic polymers and copolymers, and other film-forming media such as gelatin, gum arabic and polyvinyl alcohol. , Hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinylpyrrolidone, casein, starch, polyacrylic acid, polymethyl methacrylate, polymethacrylic acid, polyvinyl chloride, copoly (styrene-maleic anhydride),
Copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinylacetals such as polyvinylformal, polyvinylbutyral, polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetates, cellulose Esters,
There are polyamides and the like, which may be water-soluble or water-insoluble. However, among these binders, particularly preferred are water-insoluble polymers such as cellulose acetate, cellulose acetate butyrate and polyvinyl butyral. Among these, particularly preferred polymers used in the photothermographic layer include polyvinyl formals Among them, polyvinyl butyral is particularly preferred, and cellulose acetate and cellulose acetate butyrate are particularly preferred polymers as the backcoat layer for the protective layer.

In the present invention, the binder amount of the photosensitive layer is preferably from 1.5 to 6 g / m ² . More preferably, it is 1.7 to 5 g / m ² .

As the material of the support used for the photothermographic material, various polymer materials, glass, wool cloth, cotton cloth,
Paper, metal (for example, aluminum) and the like can be mentioned, but in terms of handling as an information recording material, a material that can be processed into a flexible sheet or roll is preferable. Accordingly, the support in the photothermographic material of the present invention is preferably a plastic film (eg, a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyamide film, a polyimide film, a cellulose triacetate film, a polycarbonate film, etc.). In the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferred. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.
m.

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be contained in the constituent layer in order to improve the chargeability. These may be contained in any of the layers, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat layer, and the like.
In the present invention, the conductive compounds described in U.S. Pat. No. 5,244,773, columns 14 to 20, are preferably used.

There are no particular restrictions on the method of coating the necessary layers on the light-sensitive material of the present invention, such as a light-sensitive layer, a protective layer and a back coat layer.
Methods such as dip coating, bar coating, curtain coating, and hopper coating can be used. Further, two or more of these layers may be applied simultaneously. MEK, ethyl acetate,
An organic solvent such as toluene is preferably used.

The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. For example, a protective layer is provided on the photosensitive layer to protect the photothermographic layer, and a back coat layer is provided on the opposite surface of the support to prevent sticking between photosensitive materials or in a photosensitive material roll. Is preferably provided. Further, a filter layer may be formed on the same side as or opposite to the photosensitive layer to control the amount or wavelength distribution of light transmitted through the photothermographic layer, or the photosensitive layer may contain a dye or pigment. Good. As the dye, compounds described in JP-A-8-201959 are preferred. The photosensitive layer may be composed of a plurality of layers, and a high-sensitivity layer and a low-sensitivity layer may be provided for adjusting the gradation and may be combined. Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other forming layers.

The photothermographic material of the present invention is stable at normal temperature, but is developed by heating to high temperature after exposure. The heating temperature is preferably from 80 ° C. to 200 ° C., and more preferably from 100 ° C. to 150 ° C. If the heating temperature is lower than 80 ° C., a sufficient image density cannot be obtained in a short time, and if the heating temperature is higher than 200 ° C., the binder is melted and adversely affects not only the image itself but also transportability such as transfer to a roller and a developing machine. Effect.

Exposure of the photothermographic material of the present invention can be applied to any light source, but is preferably laser exposure, particularly from the viewpoint of high laser power and transparency of the photosensitive material. And an infrared semiconductor laser (780 nm, 820 nm) are more preferably used.

In the present invention, the exposure is preferably performed by laser scanning exposure. However, it is preferable to use a laser scanning exposure machine in which the angle between the exposure surface of the photosensitive material and the scanning laser beam does not become substantially perpendicular. .

Here, "not substantially vertical" means that the angle is closest to vertical during laser scanning, preferably 55 to 88 degrees, more preferably 60 to 86 degrees, and still more preferably. 65 degrees or more and 84 degrees or less,
Most preferably, it is 70 degrees or more and 82 degrees or less.

When a laser beam is scanned on the photosensitive material, the beam spot diameter on the exposed surface of the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. It is preferable that the spot diameter is small in that the shift angle of the laser incident angle from the perpendicular can be reduced. Incidentally, the adjustment of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as occurrence of interference fringe-like unevenness.

It is also preferable that the exposure in the present invention is performed by using a laser scanning exposure machine which emits a scanning laser beam which is a vertical multi. Image quality deterioration such as generation of interference fringe-like unevenness is reduced as compared with the scanning laser beam in the longitudinal single mode.

[0159] In order to form a vertical multiple, a method such as combining, using return light, or superimposing a high frequency is preferable. still,
The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

Hereinafter, the present invention will be described in detail with reference to examples a) and b), and the present invention is not limited thereto.

[0161]

EXAMPLES The following Examples 1 to 3 relate to the invention a) [Claims 1 to 11].

Example 1 (Preparation of Photosensitive Silver Halide Emulsion 1) A1 Phenylcarbamoyl gelatin 88.3 g Compound (A) (10% aqueous methanol solution) 10 ml Potassium bromide 0.32 g Finish up to 5429 ml with water B1 0.67N Silver nitrate aqueous solution 2635 ml C1 Potassium bromide 51.55 g Potassium iodide 1.47 g Finish up to 660 ml with water D1 Potassium bromide 154.9 g Potassium iodide 4.41 g Iridium chloride (1% solution) 0.93 ml Finish up to 1982 ml with water E1 0.4N Potassium bromide aqueous solution The following silver potential control amount F1 Potassium hydroxide 0.71 g Finish to 20 ml with water G1 56% acetic acid aqueous solution The following pH adjustment amount H1 1.72 g anhydrous sodium carbonate Finish to 151 ml with water Compound (A): HO (CH ₂ CH ₂ O) _{n - (CH (CH 3)} CH 2 O) 17 - (C H 2 CH 2 O) m H m + n = 5~7 B No. 58-58288, by using a mixing and stirring machine shown in Nos. 58-58289 Solution (B1) in solution (A1)
を amount and the whole amount of the solution (C1) at a temperature of 45 ° C. and pAg
While controlling at 8.09, the mixture was added by the simultaneous mixing method in 4 minutes and 45 seconds to form nuclei.

One minute later, the entire amount of the solution (F1) was added.
After a lapse of 6 minutes, 3/4 of the solution (B1) and the solution (D
The entire amount of 1) was added over 14 minutes and 15 seconds by a double jet method while controlling the temperature to 45 ° C. and the pAg to 8.09.

After stirring for 5 minutes, the temperature was lowered to 40 ° C., pH was adjusted to 4.3 by adding solution G1, and the silver halide emulsion was sedimented. The supernatant was removed, leaving 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide emulsion was sedimented again. The supernatant was removed, leaving 1500 ml of the sedimented portion, and 10 l of water was further added. After stirring, the silver halide emulsion was sedimented. Leaving 1500 ml of sedimentation,
After removing the supernatant, the solution (H1) was added,
, And the mixture was further stirred for 120 minutes. Finally, the temperature was lowered to 40 ° C. and adjusted to pH 5.8 and pAg 8.22.
Water was added so as to be 1161 g per mole of silver.

The silver halide grains contained in this emulsion had an average grain size of 0.058 μm and a variation coefficient of grain size of 1
Cubic silver iodobromide grains of 2% and [100] face ratio of 92% were obtained. The amount of gelatin contained per mole of silver halide emulsion and silver was 37.4 g.

(Preparation of photosensitive silver halide emulsions 2 to 4)
In the preparation of photosensitive silver halide emulsion 1, 40
After cooling to ℃, an aqueous solution of carbamoyl gelatin was added to adjust the amounts of gelatin contained per mol of silver halide emulsion and silver to 116 g, 232 g and 348 g, respectively.

(Preparation of Powdered Organic Silver Salts 1-4) 4720 m
111.4 g of behenic acid and 83.Arachidic acid in 1 l of pure water.
8 g and 54.9 g of stearic acid were dissolved at 80 ° C. Next, while stirring at a high speed, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain a sodium organic acid solution. While maintaining the temperature of the above-mentioned organic acid sodium solution at 55 ° C., the above-mentioned silver halide emulsion (containing 0.038 mol of silver)
And 450 ml of pure water were added and stirred for 5 minutes. Next, 760.6 ml of a 1M silver nitrate solution was added over 2 minutes, and the mixture was further stirred for 20 minutes, and water-soluble salts were removed by filtration. Thereafter, water washing with deionized water and filtration were repeated until the conductivity of the filtrate became 2 μS / cm, and centrifugal dehydration was performed.
Powdered organic silver salts 1 to 4 were obtained.

(Preparation of Photosensitive Emulsion Dispersions 1-4) Polyvinyl butyral powder (Butvar from Monsanto)
B-79) 14.57 g of methyl ethyl ketone 1457
g of the powdered organic silver salt was gradually added thereto while stirring with a dissolver-type homogenizer, and mixed well. Thereafter, dispersion was performed at a peripheral speed of 13 m and a residence time in the mill of 0.5 minute with a media type disperser (manufactured by gettzmann) filled with 80% of 1 mm Zr beads (manufactured by Toray) to prepare photosensitive emulsion dispersions 1 to 4. did.

(Preparation of Photographic Support) Concentration: 0.170
(Measured with a densitometer PDA-65 manufactured by Konica Corporation) A corona discharge treatment of 8 W / m ² · min was applied to both sides of a 175 μm thick PET film colored blue.

<Coating of photosensitive layer> (Preparation of photosensitive layer coating solutions 1 to 4) The above-mentioned photosensitive emulsion dispersion (500 g) and methyl ethyl ketone (MEK) 10
0 g was kept at 21 ° C. while stirring.

Pyridinium hydrobromide perbromide (PHP, 0.45 g) was added and stirred for 1 hour.

Further, calcium bromide (3.25 ml of a 10% methanol solution) was added, and the mixture was stirred for 30 minutes.

Next, sensitizing dye-A, 2-chlorobenzoic acid,
And a mixed solution of a supersensitizer (5-methyl-2-mercaptobenzimidazole) (mixing ratio 1: 250: 2)
0, 0.1% methanol solution with a sensitizing dye (7 ml) is added, and the mixture is stirred for 1 hour, and then the temperature is lowered to 13 ° C. and further stirred for 30 minutes.

While keeping the temperature at 13 ° C., 48 g of polyvinyl butyral is added and sufficiently dissolved, and then the following additives are added.

Developer (1,1-bis (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane) 15 g Desmodur N3300 (Mobay, aliphatic isocyanate) 1.10 g Phthalazine 1.5 g Tetrachlor 0.5 g of phthalic acid 0.5 g of 4-methylphthalic acid

[0176]

Embedded image

After each of the photosensitive layer coating solutions 1 to 4 was prepared as described above, the solution was kept at 13 ° C. and kept stagnant for 15 minutes, and then applied by the following method. Further, the following layers were sequentially formed on a support to prepare a sample. In addition, each drying was performed at 75 ° C. for 5 minutes.

<Back side coating> (Preparation of back side coating liquid) 830 g of methyl ethyl ketone
While stirring the cellulose acetate butyrate (E
astman Chemical, CAB 381-2
0) 84.2 g, polyester resin (Bostic,
(VitelPE2200B) 4.5 g was added and dissolved. 0.30 g of infrared dye-1 was added to the dissolved solution,
Further, 4.5 g of an F-based activator (Asahi Glass Co., Ltd., Surflon KH40) dissolved in 43.2 g of methanol and 2.3 g of an F-based activator (Dainippon Inc., Megafag F120K)
Was added and the mixture was sufficiently stirred until it was dissolved. Finally, silica (WR Gra) dispersed in methyl ethyl ketone at a concentration of 1 wt% with a dissolver-type homogenizer.
75 g of Syloid 64X6000 (ce Co., Ltd.) was added and stirred to prepare a coating solution for the back surface.

The back surface coating solution thus prepared was
Coating and drying were performed with an extrusion coater so that the dry film thickness became 3.5 μm. Drying temperature 100 ° C, dew point 10 ° C
And dried for 5 minutes using a drying air.

<Surface protective layer coating> (Preparation of dispersion) Cellulose acetate butyrate (E
astman Chemical, CAB171-1
5) Dissolve 7.5 g in 42.5 g of MEK, in which
Calcium carbonate (Specialty Minera)
5 g of Super-Pflex 200 (Iss. Co., Ltd.) was added, and the mixture was dispersed with a dissolver-type homogenizer at 8000 rpm for 30 minutes to prepare a calcium carbonate dispersion.

(Preparation of Surface Protective Layer Coating Solution) Cellulose acetate butyrate (Eastman Chemical Co., CA) was stirred with 865 g of methyl ethyl ketone.
B171-15) and 4.5 g of polymethyl methacrylic acid (Rohm & Haas Co., Ltd., Paraloid A-21) were added and dissolved. 1.5 g of a vinyl sulfone compound HD-1, 1.0 g of benzotriazole, and 1.0 g of an F-based activator (Asahi Glass Co., Ltd., Surflon KH40) were added to this solution and dissolved. Finally, 30 g of the calcium carbonate dispersion was added and stirred to prepare a coating solution for the surface protective layer.

<Coating on photosensitive layer surface side>
No. 4 and the coating solution for the surface protective layer were simultaneously coated using an extrusion coater. The photosensitive layer has a coated silver amount of 2.4 g / m ² , and the surface protective layer has a dry thickness of 2.5 μm.
m at a speed of 20 m / min. Thereafter, using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C., 10
After drying for 5 minutes, photosensitive materials 1 to 4 were prepared.

Table 1 shows the gelatin content of the light-sensitive materials 1 to 4.

<Evaluation of Photosensitive Material> The photosensitive materials 1 to 4 obtained by the above method were exposed to laser light from the emulsion side by laser scanning using an exposing machine using a semiconductor laser having a wavelength of 810 nm as an exposure source. Was. At this time, an image was formed with the angle between the exposure surface of the photosensitive material and the exposure laser beam being 75 degrees. After exposing with a laser under the above conditions, 120
C. for 15 seconds. After development, measurement was performed with a densitometer PDA-65 manufactured by Konica Corporation, and fog and sensitivity were measured.
Gamma was measured. The sensitivity was represented by the reciprocal of the ratio of the exposure amount giving a density higher than fog by 1.0. Further, the obtained image was allowed to stand under room light for two days, and the fog of the unexposed portion was measured again, and the storability of the image was observed.

In addition, a set of samples was prepared separately,
After being stored in a light-shielding container at 0 ° C. and a relative humidity of 55% for 3 days, the exposed and developed products were similarly evaluated by sensitometry.

The photosensitive material 1 was 100
It is shown as a relative value when Regarding the decrease in gamma, the gamma of the sample developed immediately after coating was set to 100, and the reduction rate was indicated by%.

[0187]

[Table 1]

It should be noted that, in the above examples, when the laser exposure angle was set to the above value, the unevenness was smaller and the sharpness and the like were unexpectedly better than when the angle was set to 90 degrees. was gotten.

Example 2 (Preparation of Photosensitive Silver Halide Emulsion 5) A5 Phenylcarbamoyl gelatin 88.3 g Compound (A) (10% aqueous methanol solution) 10 ml Potassium bromide 0.13 g Finished with water to 5429 ml B5 0.67N Silver nitrate aqueous solution 2635 ml C5 Potassium bromide 72.17 g Potassium iodide 2.05 g Make up to 707 ml with water D5 Potassium bromide 216.8 g Potassium iodide 6.17 g Iridium chloride (1% solution) 1.30 ml Make up to 2131 ml with water E5 0.4N Potassium bromide aqueous solution The following silver potential control amount F5 Potassium hydroxide 0.71g Finish to 20ml with water G5 56% acetic acid aqueous solution The following pH adjustment amount H5 Potassium hydroxide 1.88g Finish to 210ml with water Same as Example 1 Using a mixing stirrer, the solution (A ) 1/4 amount and a solution of solution (B5) (C5) temperature the total amount 45
While controlling the temperature and the pAg at 8.09, the mixture was added by the simultaneous mixing method over 6 minutes and 39 seconds to form nuclei. After one minute,
The entire amount of the solution (F5) was added. After 6 minutes, 3/4 of the solution (B5) and the total amount of the solution (D5)
While controlling at 5 ° C. and pAg of 8.09, the mixture was added over 19 minutes and 57 seconds by a double jet method.

After stirring for 5 minutes, the temperature was lowered to 40 ° C., pH was set to 4.2 by adding solution G5, and the silver halide emulsion was precipitated. The supernatant was removed except for the sedimented portion of 2800 ml, and 14 l of water was added. After stirring, the silver halide emulsion was sedimented again. The supernatant was removed, leaving 2100 ml of the sedimented portion, and 14 l of water was further added. After stirring, the silver halide emulsion was sedimented. Leaving 2100 ml of sedimentation part,
After removing the supernatant, the solution (H5) was added,
, And the mixture was further stirred for 120 minutes. Finally, the temperature was lowered to 40 ° C. and adjusted to pH 5.8 and pAg 8.22.
Water was added so as to be 1161 g per mole of silver.

The silver halide grains contained in the photosensitive halide emulsion 5 were cubic silver iodobromide grains having an average grain size of 0.068 μm, a grain size variation coefficient of 13%, and a [100] face ratio of 92%. . The amount of gelatin contained per mole of silver in the silver halide emulsion was 28.1.
g.

(Preparation of Photosensitive Silver Halide Emulsion 6) In the preparation of the photosensitive silver halide emulsion 6, the gelatin of the solution (A5) was changed from carbamoyl gelatin to ossein gelatin. Also, after stirring for 5 minutes after mixing is completed,
After the temperature was lowered to 0 ° C., 6000 ml of an aqueous solution containing 600 g of carbamoyl gelatin was added, and then a solution (G5) was added to adjust the pH to 4.2, whereby a silver halide emulsion was precipitated. The supernatant was removed, leaving 4200 ml of sedimentation, and 2
After adding 1 liter and stirring, the silver halide emulsion was precipitated again. The supernatant was removed, leaving 3150 ml of the sedimented portion, and 21 l of water was further added. After stirring, the silver halide emulsion was sedimented. After removing the supernatant, leaving 3150 ml of the sedimented portion, the solution (H6) was added, and the temperature was raised to 60 ° C.
The mixture was further stirred for 120 minutes. Finally, the temperature is lowered to 40 ° C,
5.8 and pAg 8.22 were adjusted, and water was added so that the amount became 1359 g per mol of silver.

H6 Potassium hydroxide 12.8 g Finished to 210 ml with water Silver halide grains contained in this photosensitive halide emulsion 6 have an average grain size of 0.068 μm, a variation coefficient of grain size of 13%, and a [100] face ratio It was 92% cubic silver iodobromide grains. The amount of gelatin contained per mole of silver in the silver halide emulsion was 220 g.

(Preparation of Photosensitive Silver Halide Emulsion 7) In the preparation of the photosensitive silver halide emulsion 5, 5
After stirring for minutes, the temperature was lowered to 40 ° C., and pH was adjusted to 5.2 by adding solution G5 to precipitate a silver halide emulsion. The supernatant liquid was removed, leaving 3360 ml of the sedimented portion.
After adding 6.8 l and stirring, the silver halide emulsion was precipitated again.

The supernatant was removed, leaving 2520 ml of the sedimented portion, and 16.8 l of water was further added. After stirring, the silver halide emulsion was sedimented. Leaving 2520 ml of sedimentation,
After removing the supernatant, the solution (H7) was added,
, And the mixture was further stirred for 120 minutes. Finally, the temperature was lowered to 40 ° C. and adjusted to pH 5.8 and pAg 8.22.
Water was added so as to be 1161 g per mole of silver.

The silver halide grains contained in this photosensitive halide emulsion 7 were cubic silver iodobromide grains having an average grain size of 0.068 μm, a grain size variation coefficient of 13% and a [100] face ratio of 92%. . In the silver halide emulsion, the amount of gelatin contained per mole of silver was 4.64.
g.

H7 Potassium hydroxide 1.22 g Finished to 210 ml with water Instead of silver halide emulsion 1, the above silver halide emulsions 5 to 7
And photothermographic materials 5 to 7 were prepared in the same manner as in Example 1, and the same evaluation was performed. Table 2 shows the evaluation results.

[0198]

[Table 2]

Example 3 (Preparation of Photosensitive Silver Halide Emulsion 8) In the preparation of Photosensitive Silver Halide Emulsion 1, in the mixing step, the phenylcarbamoyl gelatin in the solution (A1) was changed to ossein gelatin having an average molecular weight of 25,000. Except for the above, it was prepared in the same manner as in photosensitive silver halide emulsion 1.

Subsequently, the mixture was concentrated and desalted at 40 ° C. using an ultrafiltration membrane having a molecular weight cut off of 10,000. After desalting, pH
5.8 and pAg of 8.22 were added, and water was added so as to be 1161 g per mol of silver to obtain a photosensitive silver halide emulsion 8.

The silver halide grains contained in Emulsion 8 were cubic silver iodobromide grains having an average grain size of 0.058 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%. The amount of gelatin contained per mole of silver in the silver halide emulsion was 49.9 g.

(Preparation of photosensitive silver halide emulsion 9) Photosensitive silver halide emulsion 8 was prepared in the same manner as in preparation of photosensitive silver halide emulsion 8, except that the gelatin used in the mixing step was changed to ossein gelatin having an average molecular weight of 105000. In the same manner as in No. 8, photosensitive silver halide emulsion 9 was prepared.

The silver halide grains contained in Emulsion 9 were cubic silver iodobromide grains having an average grain size of 0.058 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%. The amount of gelatin contained per mole of silver in the silver halide emulsion was 49.9 g.

(Preparation of Photosensitive Silver Halide Emulsion 10)
A light-sensitive silver halide emulsion 10 was prepared in the same manner as in the light-sensitive silver halide emulsion 8, except that the ultrafiltration membrane was changed to 00000.

The silver halide grains contained in Emulsion 10 were cubic silver iodobromide grains having an average grain size of 0.058 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%. The amount of gelatin contained per mole of silver in the silver halide emulsion was 2.9 g.

Photographic materials 8 to 10 were prepared using the emulsions 8 to 10 described above. The photosensitive material was produced by the same manufacturing method as in Example 1, and was evaluated in the same manner as in Example 1. Table 3 shows the results.

It can be seen that, in the method for producing a light-sensitive material of the present invention, it is more preferable to use low molecular weight gelatin in the mixing step and to carry out ultrafiltration desalting. In addition, it can be seen that low molecular weight gelatin is washed off with an ultrafiltration membrane and the gelatin content is undesirably reduced.

[0208]

[Table 3]

The following Example 4 is an example of the invention b) [Claims 12 to 14].

Example 4 (Preparation of Support) Concentration of 0.170 (densitometer PDA-65 manufactured by Konica Corporation) was colored blue and had a thickness of 175.
A corona discharge treatment of 8 W / m ² · min was applied to both sides of a μm PET film.

(Preparation of Photosensitive Silver Halide Emulsion A) Water 9
6. Ossein gelatin having an average molecular weight of 100,000 in 00 ml
5 g and 10 mg of potassium bromide were dissolved at a temperature of 35 ° C.
After adjusting the pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate, potassium bromide and potassium iodide in a molar ratio of (98/2) are equivalent to silver nitrate, and iridium chloride is 1 × 10 ⁻ per mol of silver. 370 ml of an aqueous solution containing ⁴ moles was pA
While maintaining the g at 7.7, the mixture was added over 10 minutes by the controlled double jet method. Then 4-hydroxy-6
-Methyl-1,3,3a, 7-tetrazaindene 0.3
g, the pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, the coefficient of variation of the particle size was 12%, and [10
0] Cubic silver iodobromide grains having an area ratio of 87% were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant and desalting treatment, and then 0.1 g of phenoxyethanol was added thereto.
9, and adjusted to a pAg of 7.5 to obtain a photosensitive silver halide emulsion A.

(Preparation of Powdered Organic Silver Salt A) 111.4 g of behenic acid and 83.8 of arachidic acid were added to 4720 ml of pure water.
g and 54.9 g of stearic acid were dissolved at 80 ° C. Next, while stirring at a high speed, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added. Next, after adding 6.9 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. to obtain a sodium organic acid solution. While maintaining the temperature of the organic acid sodium acid solution at 55 ° C., the above silver halide emulsion (containing 0.038 mol of silver)
And 450 ml of pure water were added and stirred for 5 minutes. Next, 760.6 ml of a 1M silver nitrate solution was added over 2 minutes, and the mixture was further stirred for 20 minutes, and water-soluble salts were removed by filtration. Thereafter, water washing with deionized water and filtration were repeated until the conductivity of the filtrate became 2 μS / cm, and centrifugal dehydration was performed.
A powdered organic silver salt A was obtained.

(Preparation of photosensitive emulsion dispersion) Polyvinyl butyral (Butvar B-7 manufactured by Monsanto)
9) 14.57 g of methyl ethyl ketone (hereinafter, abbreviated as MEK) was dissolved in 1457 g, and 500 g of powdered organic silver salt A was gradually added while stirring with a dissolver-type homogenizer, followed by sufficient mixing. Thereafter, a media type dispersing machine (Gettz) filled with 80% of 1 mm diameter Zr beads (manufactured by Toray)
13m, residence time in the mill 0.5
For 1 minute to prepare a photosensitive emulsion dispersion.

<Preparation of infrared sensitizing dye liquid> Infrared sensitizing dye 1
Was dissolved in methanol (73.4 ml) in a dark place to prepare an infrared sensitizing dye solution. 350 mg, 2-chloro-benzoic acid (13.96 g) and 5-methyl-2-mercaptobenzimidazole (2.14 g) were dissolved in dark place.

<Preparation of Stabilizer 1 Solution>
g and 0.5 g of potassium acetate were dissolved in 8.5 g of methanol to prepare a stabilizer solution.

<Preparation of developer solution> As a developer, 1,1-
(2-hydroxy-3,5-dimethylphenyl) -2-
Dissolve 17.74 g of methyl propane in MEK and add 100
ml and used as a developer solution.

<Preparation of Antifoggant 2 liquid> 5.81 g of Antifoggant 2 was dissolved in MEK, and finished to 100 ml.

(Preparation of Coating Solution for Photosensitive Layer) 50 g of the photosensitive emulsion dispersion and 15.11 g of MEK were kept at 21 ° C. while stirring, 390 μl of antifoggant 1 (10% methanol solution) was added, and the mixture was stirred for 1 hour. did. Further, 889 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 30 minutes.

Next, 1.416 ml of the infrared sensitizing dye solution and 667 μl of the stabilizer solution were added, and the mixture was stirred for 1 hour. Then, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes.

While keeping the temperature at 13 ° C., polyvinyl butyral (Butvar B-79, Monsanto)
After adding 13.31 g and stirring for 30 minutes, the following additives were added at intervals of 15 minutes while stirring was continued.

Phthalazine 305 mg Tetrachlorophthalic acid 102 mg 4-Methylphthalic acid 137 mg Infrared dye 1 37 mg After adding the above and stirring for 15 minutes, antifoggant 2 solution 100 ml The developer solution 14.06 ml 1.60 ml of a 10% MEK solution (shown in No. 1) were sequentially added and stirred to obtain a photosensitive layer coating solution.

[0222]

Embedded image

[0223]

Embedded image

The following layers were sequentially formed on a support to prepare Sample 1. The drying was performed at 75 ° C. for 5 minutes.

<Coating on Back Side> Cellulose acetate (10% methyl ethyl ketone solution) 15 ml / m ² Matting agent: Monodispersity 15% Average particle size 10 μm Monodisperse silica 30 mg / m ² <Photosensitive layer side coating> Photosensitive layer: The above Was applied so that the applied silver amount was 2 g / m ² .

Surface protective layer: A solution having the following composition was applied on the photosensitive layer.

Methyl ethyl ketone 17 ml / m ² Cellulose acetate 2.3 g / m ² Matting agent: Monodispersity 10% Average particle size 4 μm Monodisperse silica 70 mg / m ² Alternatively, the protective layer of the present invention may be used as follows. A sample to which the compound was added was prepared.

Sample 2: Carnauba wax in the protective layer
Sample 1 was prepared in the same manner as in Sample 1 except that 1 g / m ² was added.

Sample 3: Carnauba wax was added to the protective layer in an amount of 0.1%.
Sample 1 was prepared in the same manner as in Sample 1 except that an amount of 5 g / m ² was added.

Sample 4: Microcrystalline wax Hi-Mic-1045 (manufactured by Nippon Seiro Co., Ltd.) for the protective layer
Was added in the same manner as in Sample 1 except that 0.1 g / m ² was added.

<< Exposure and Development Processing >> Samples 1 to 4 were superposed at a high frequency of 800 nm to 820 from the emulsion side.
Exposure was performed by laser scanning using an exposure machine using a semiconductor laser having a vertical multi-mode of nm as an exposure source.
At this time, an image was formed with the angle between the exposure surface of the photosensitive material and the exposure laser beam being 75 degrees. (Note that the angle is 90
An image with less unevenness and unexpectedly good sharpness was obtained as compared with the case of the degree. Thereafter, the protective layer of the photosensitive material is brought into contact with the surface of the heating member by a thermal developing device using a heating member having a flexible layer of silicon rubber on an aluminum tube as shown in FIG. The heat development process was carried out at the transfer speed. An evaluation was made as to the number of sheets in which damage to the material occurred due to transport from the start of the processing of the film. When film damage occurred, development unevenness always occurred in the next film.

The development processing speed was evaluated by the time required to obtain a constant density (1.0) at the same exposure amount by changing the transport speed while keeping the temperature constant.

[0233] It can be seen that material damage is significantly improved in the present invention. Further, the photosensitive material of the present invention can also reduce the occurrence of scratches due to adhesion to the roller and the occurrence of uneven development due to the generation of foreign matters.

Evaluation of transportability When transported at a transport speed of 150 ° C. for 10 seconds using the apparatus used for the evaluation of transport flaws, the occurrence frequency of transport trouble was evaluated. The transport trouble was a phenomenon in which the film was not sent to the next transport roller after the thermal developing drum because the film was stuck to the thermal developing drum and did not separate.

The heat development drum of the developing device was changed from silicon rubber to metal (mirror-finished aluminum) for evaluation.

Silicon rubber Aluminum Sample 1 5 / 10,000 23 / 10,000 Sample 2 No generation 21 / 10,000 Sample 3 No generation 40 / 10,000 It can be seen that transportability was improved in the present invention. In particular, there was a remarkable effect in combination with silicon rubber.

Evaluation of Image Failure Occurred by Developing Different Size Films The samples were cut into two sizes, 8 × 10 inches and 14 × 17 inches, and developed. The heating member of the heat developing apparatus was returned to the one having the flexible layer of silicon rubber as in Example 1, and development was performed. At this time, if the small size (8 × 10 inch) is processed first, and then the large size (14 × 17 inch) is processed, minute deposits are generated at the positions corresponding to the portions where the small size sides contact the drum. As a result, the adhesion between the large-size film and the drum is deteriorated, and uneven development occurs. This frequency was evaluated.

[0238] According to the present invention, it can be seen that development unevenness which occurs when photosensitive materials having different film sizes are continuously processed is improved. As a result, even when a film of the same size is subjected to development processing by shifting the transport position to the left or right, a result with a small development unevenness was similarly obtained in the present invention.

[0239]

The object of the invention a) is to provide a photothermographic material having high sensitivity, low fog, little change in characteristics of the photosensitive material due to storage, and excellent in image stability.

According to the invention b), scratches and defective transport of the film during thermal development are improved. Further, development unevenness that occurs when developing films of different sizes or when the transport position is shifted is significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a heat developing device.

FIG. 2 is a side view of a heating member and a guide member.

FIG. 3 is a cross-sectional view of the heat developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating member 2 Guide member 3 Processor frame 4 Processor end member 5 Guide member bracket 6 Shaft 7 Shaft bearing 8 Belt 9 Belt drive device 10 Spring 11 Guide member shaft 12 Slender opening 21 Aluminum tube 22 Heater blanket 23 Flexible layer A Inlet S Photothermographic material X Guide plate for peeling

Claims (15)

[Claims] 1. A photothermographic material comprising a support containing a photosensitive silver halide emulsion, an organic silver salt, a reducing agent for silver ions and a hydrophobic binder, wherein gelatin is 45 mg / m 2.
^A photothermographic material comprising ^{2 to} 500 mg / m ² . 2. The photothermographic material according to claim 1, wherein the gelatin content of the photosensitive silver halide emulsion is in the range of 5 g to 200 g per mol of silver halide. 3. The process of mixing a photosensitive silver halide emulsion contained in the photothermographic material according to claim 1 or 2 with a silver salt aqueous solution and a halide aqueous solution in a gelatin aqueous solution and a desalting step. A method for producing a photothermographic material, wherein the photothermographic material is prepared in the step of preparing a silver halide emulsion. 4. The amount of gelatin contained in the aqueous gelatin solution used in the mixing step is from 5 g to 1 kg per mol of the prepared silver halide.
3. The method for producing a photothermographic material according to item 1. 5. The desalting step, wherein the gelatin content of the silver halide emulsion is from 5 g to 200 g per mol of silver halide.
5. The method for producing a photothermographic material according to claim 3, wherein the value is reduced to the range of g. 6. The aqueous gelatin solution used in the mixing step contains amino group-blocked gelatin, and the pH of the desalting step is set to 5.1 or less.
Or the method for producing a photothermographic material according to item 5. 7. The aqueous gelatin solution used in the mixing step contains low molecular weight gelatin having a molecular weight of 30,000 or less,
6. The method for producing a photothermographic material according to claim 3, wherein the desalting step is performed by an ultrafiltration method. 8. A method for processing a photothermographic material, wherein the photothermographic material according to claim 1 is thermally developed at a temperature of 80 ° C. to 140 ° C. 9. An image forming method, wherein an image is obtained by exposing the photothermographic material according to claim 1 to infrared light and thermally developing the material at a temperature of 80 ° C. to 140 ° C. 10. A processing temperature of 80 ° C. to 140 ° C. after exposing the photothermographic material according to claim 1 to a laser beam.
An image forming method, wherein an image is obtained by heat development at a temperature of ° C. 11. The image forming method according to claim 10, wherein the exposure by the laser beam does not become substantially perpendicular to the photosensitive material. 12. A photosensitive silver halide emulsion on a support,
A photothermographic material comprising an organic silver salt, a reducing agent for silver ions, a hydrophobic binder and a wax. 13. The photothermographic material according to claim 12, wherein the outermost layer contains wax as viewed from the support. 14. An image forming method comprising thermally developing the photothermographic material according to claim 12 at a temperature of 80 ° C. to 140 ° C. 15. A heat developing device for developing a photothermographic material according to claim 12, wherein a surface of a heating member of the heat developing device in contact with the photothermographic material is made of silicone rubber. A heat development device for a heat development photosensitive material.