JPS604454B2 - Heat-developable photosensitive material for electrostatic printing masters - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-developable photosensitive material for electrostatic printing masters, and more particularly to a heat-developable photosensitive material for electrostatic printing masters containing an organic silver salt. It is.

Conventionally, photosensitive materials containing silver halide have been widely used in image formation, but because the development and fixing processes are wet, the processing steps are complicated and time-consuming, and the processing work must be done in a darkroom. However, there are still many points that can be improved, such as having to carry out the following procedures and having many negative effects on the human body.

Recently, however, attempts have been made to carry out the above-mentioned wet processing process in a dry process, and a representative example of this is as described in Japanese Patent Publication No. 431-4924, which uses organic silver salts as the main ingredient. There is an image forming method in which a heat-developable photosensitive material containing a catalytic amount of photosensitive silver halide and a reducing agent is exposed to light and then thermally developed to obtain a visible image.

This image forming method is an image forming method that has recently attracted a lot of attention because the entire process is a dry process, and the development and improvement of the heat-developable photosensitive materials used are extremely active, and at the same time, there are many fields in the field. Its uses can be further expanded, such as by being able to be used as a recording material in applications, and furthermore, as a master forming material for electrostatic printing as described in Japanese Patent Laid-Open No. 51-24308, which the present applicant previously filed. It is.

However, in such heat-developable photosensitive materials, a latent image is formed by liberating a certain amount of silver from a catalytic amount of photosensitive silver halide through image exposure, and in the subsequent heat development process, this liberated silver is released. A visible image is formed by a certain amount of silver being liberated from an organic silver salt and acting as a development nucleus for the precipitated silver.

That is, since it is mainly composed of an organic silver plate which is not substantially photosensitive, there are problems such as not being able to obtain a sufficiently satisfactory photosensitivity, and also not being able to sufficiently increase photographic density. From a further point of view, it is usually used to form an image by taking advantage of the difference in reaction rate between the organic silver salt and the reducing agent in the exposed and non-exposed areas during image exposure and thermal development. It has been extremely difficult to obtain images as high in contrast as the silver halide emulsion photographic materials currently available.

For example, in both the exposed and non-exposed areas, the organic silver salt reacts with the reducing agent to precipitate silver particles, regardless of the degree of reactivity. If the difference in reaction rate is small, when processing is performed to produce a sufficient image, the reaction proceeds even in non-exposed areas, causing so-called ground-covering to occur and the entire image to be slightly smeared.
The image becomes clogged and the contrast becomes low. On the other hand, if the reaction in the non-exposed area is attempted to be suppressed, sufficient image formation will not be possible, making it impractical. Furthermore, when such a heat-developable photosensitive material is used as a forming material for the electrostatic printing master described in JP-A-51-24308, which was previously proposed by the present applicant, the above-mentioned This point is very inconvenient.

That is, the electrostatic printing master is obtained by subjecting a heat-developable photosensitive material to imagewise exposure and heat development as described above to form a silver image pattern, and the electrostatic printing method is as follows. An electrostatic printing master having a silver image pattern is subjected to electrostatic charging, development, and transfer processes, and the principle is that during the charging process, the exposed area (silver image area) of the master becomes conductive. This is based on the fact that electrostatic contrast occurs because the non-exposed area (non-ferrous image area) has the ability to hold static charge.

Therefore, if silver is not sufficiently deposited in exposed areas (silver image areas), or silver is deposited in non-exposed areas (non-silver image areas), causing so-called ground breaking, the Since high electrostatic contrast may not be obtained in some cases, printed matter with excellent image quality cannot be obtained, making it impractical. For the above reasons, the photographic density is high, and the difference in reaction rate between the exposed and unexposed areas is sufficiently large.In other words, the reaction in the unexposed areas is sufficiently suppressed, and the exposed areas are There is a need for the development of heat-developable photosensitive materials that can sufficiently promote this process.

Furthermore, from the perspective of materials for forming electrostatic printing masters previously proposed by the present applicant, the development of heat-developable photosensitive materials from which electrostatic printing masters with excellent electrostatic properties can be formed is one step further. This is highly desired.

In view of the above points, the present inventors have comprehensively studied various heat-developable photosensitive materials containing organic silver salts. Recognizing that there are many points that could be improved, such as the type of silver salt and the method of dispersing it in the binder, the quantitative relationship between the organic silver salt and the binder, and the type of binder, the above-mentioned As a result of intensive research aimed at solving all of these problems, we have succeeded in developing the desired excellent heat-developable photosensitive material for electrostatic printing masters as described above.

The present invention is a heat-developable photosensitive material for electrostatic printing masters that has high photographic density and has excellent image properties with a sufficiently large difference in reaction rate between the organic silver salt and the reducing agent in the exposed and non-exposed areas. The main purpose is to provide materials.

Another object of the present invention is to provide a heat-developable photosensitive material for electrostatic printing masters having excellent electrostatic properties.

The present invention is directed to the existence of an organic relationship in the manner in which the organic silver salt exists in the binder, the quantitative relationship between the organic silver salt and the binder, the type of binder, and the manufacturing method. The present invention is further based on the discovery that the above purpose can be achieved when such organic relationships meet certain conditions.

That is, the present invention specifies fatty acid silver salts as organic silver salts,
By allowing the fatty acid silver salt to coexist with an organic acid at a certain molar ratio in the binder, and by creating a certain quantitative relationship between the amount of a certain type of binder and the amount of fatty acid silver salt. Therefore, the above-mentioned drawbacks are compensated for and the purpose of the present application is fulfilled.

The heat-developable photosensitive material for electrostatic printing master of the present invention has m of fatty acid silver salt relative to the total mol number of fatty acid silver salt and organic acid.
A ratio of 0.02 to 2 parts by weight of a binder with respect to 1 part by weight of the fatty acid silver salt, the main components being a fatty acid silver salt with an hol% of 1 to 1% or more, an organic acid, and a halide. Dispersed in a binder having a specific resistance of 1bioQ skin or more and a dielectric breakdown strength of 10KV/willow or more, and whose equilibrium moisture content is 3.0% or less at a relative temperature of 20 to 100%. It is characterized by the following.

In the present invention, the fatty acid silver salt and the organic acid can be made to coexist in the binder by mixing the fatty acid silver salt and the organic acid in advance and dispersing the mixture in the binder. , a method of mixing an organic acid and a binder, and a co-pillar mixture of fatty acid silver salts obtained by co-precipitating fatty acid silver salts in the step of producing fatty acid silver salts (hereinafter referred to as co-pillar mixtures of fatty acid silver salts, unless otherwise specified). There is a method of dispersing a coprecipitated mixture of fatty acid silver salt and fatty acid in a binder. This method is particularly effective for dispersing during deposition.

The fatty acid and organic acid in the fatty acid silver salt coexisting in the binder may be the same acid or different acids, and multiple types of fatty acid silver salts and multiple types of organic acids may be coexisting. It is something.

Specifically, for example, a system of behenic acid and silver behenate, a system of capric acid and silver behenate, a system of behenic acid/stearic acid and silver behenate, and a system of behenic acid/stearin. These combinations include a system of acid and silver behenate/silver stearate, a system of silver behenate and arachidic acid, etc.

In the present invention, the ratio of fatty acid silver salt and organic acid coexisting in the binder may be determined as desired; It is desirable that the salt content is usually 1 hol% or more.

This means that if the fatty acid silver salt is 1 hol%,
Because the absolute amount of silver contained in the photosensitive material decreases, the contrast of the silver image is low, there is a lot of fog, and only a pale image can be obtained. This is because only low contrast can be obtained and it is not practical. Therefore, in order to have a sufficiently high electrostatic contrast and a sufficient range of gradation expression,
The ratio of fatty acid silver salt to organic acid is preferably 40 hol% based on the total mol of fatty acid silver salt and organic acid.
As mentioned above, it is optimally desirable that it be 6 hol% or more. However, in order to increase the contrast, it is necessary to contain an organic acid in order to sufficiently increase the difference in reaction rate between the organic acid silver salt and the reducing agent in the exposed and non-exposed areas. Even a very small amount of the organic acid contained has a significant effect. Taking this point into consideration, the upper limit of the ratio of the fatty acid silver salt to the organic acid is set to be less than 10 hol% of the fatty acid silver salt relative to the total mol number of the fatty acid silver salt and the organic acid. Preferred fatty acid filament salts used in the present invention include, for example, the following.

Silver acetate, silver propionate, silver butyrate, silver valerate, silver caproate, silver henanthate, silver caprate, silver belargonate,
Silver caprate, silver undecylate, silver laurate, silver tridecylate, silver syristate, silver bentadecinate, silver palmitate, silver heptadecylate, silver stearate, silver nonadecanoate, silver arachate, silver behenate, Silver lignocerate, silver cerotate, silver heptacate, silver montanate, silver melisinate, silver lactate, silver acrylate, silver crotonate, silver 5-hexenoate, silver 2-octenoate, silver oleate, silver 4-tetradecenate. , silver 13-docosenoate, silver stearate, silver behenolate, silver 9-undecinate, and the like. Further, examples of organic acids include the following. {a} As fatty acids, acetic acid, propionic acid,
Butyric acid, cyanobic acid, caproic acid, enanthic acid, capric acid,
Verargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, silistylic acid, bentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, heptacanoic acid, Montanic acid, melisic acid, lactic acid, acrylic acid, crotonic acid, 5-hexenoic acid, 2-
Fatty acids such as octenoic acid, oleic acid, 4-tetradecenoic acid, 13-docosenoic acid, stearolic acid, behenolic acid, 9-undecenoic acid, and the like.

・[b} Other organic acids arachidic acid, hydroxystearic acid, benzoic acid, 4
1-n-ocdadecyloxydifconyl-4-carboxylic acid, 0-aminobenzoic acid, acetamidobenzoic acid, p-phenylbenzoic acid, phthalic acid, salicylic acid, oxalic acid, p
-nitrobenzoic acid, p-aminobenzoic acid, pyriconic acid,
Quinolinic acid, Q・Q′-dithiodibropionic acid, B・8
'Diothidiopropionic acid, thiobenzoic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, taurine, p-toluenesulfinic acid, p-acetaminobenzenesulfinic acid, diethyldithiocarbamic acid, etc. .

The heat-developable photosensitive material for electrostatic mastering of the present invention is usually prepared by preparing a coprecipitated mixture of fatty acid silver and an organic acid or fatty acid silver in a binder using a suitable solvent and a small amount of halide relative to the fatty acid silver. The organic silver salt layer is formed by mixing and dispersing the mixture and dispersing it on a suitable support by a method such as coating, and then mixing and dispersing it in a binder using a suitable solvent and applying it on a suitable support. By coating the organic silver salt layer on the surface of the organic silver salt layer to form an organic silver salt layer, and then mixing the mixture with a resin such as cellulose acetate using an appropriate solvent and coating it on the surface of the organic silver salt layer to form a reducing agent layer. That's what you get.

Further, among the above-mentioned constituent components, the reducing agent may be contained in the organic silver salt layer, or furthermore, it may be contained in the organic silver salt layer and further applied by coating on the surface of the layer as described above. It is something.

Alternatively, each of the above constituent components may be separately provided in each layer, or the reducing agent may be applied to the surface of the organic silver salt layer after image exposure and thermally developed. It's a good thing.

The halides used in such heat-developable photosensitive materials include the following inorganic halides and halogen-containing organic compounds.

{1} Inorganic halide The inorganic halide is preferably one represented by the general formula MXm.

In the formula, X represents halogen (CI, Br, 1), and when m is 2 or more, X may be the same type of halogen or different halogens. M is hydrogen, ammonium, metal (e.g. potassium, sodium, lithium, calcium, strontium, cadmium, chromium, rubidium, copper, nickel,
(magnesium, zinc, lead, platinum, palladium, bismuth, thallium, ruthenium, gallium, indium, rhodium, beryllium, cobalt, mercury, barium, silver, cesium, lanthanum, iridium, aluminum, etc.), and m represents hydrogen and ammonium. case is 1 and M
If is a metal, indicate its valence. Furthermore, silver chlorobromide, silver chlorobromoiodide, silver bromoiodide, and silver chloroiodide are also suitably employed. ■
Halogen-containing organic compounds carbon tetrachloride, chloroform, trichloroethylene, triphenylmethyl chloride, triphenylmethyl bromide, iodoform, fluoride.

These include lomoform, cetylethyldimethylammonium bromide, and the like. The aforementioned halides may be used alone or in combination of two or more.

The amount of halide added is usually 1 mol or less, preferably 10-1 mol to 10-1 mol per 1 mol of fatty acid silver salt.
5 mol is desirable. Typical reducing agents are shown below.

Hydroquinone; methylhydroquinone; chlorohydroquinone; promohydroquinone; catechol; pyrogallol; methylhydroxynaphthalene; aminophenol; 212'-methylenepis (6-t-butyl-4-methylphenol);
-butyl-3-methylphenol); 4,4-bis(6
-t-phthyl-3-methylphenol); 4,4'-thiobis(6-t-2-methylphenol);2,6-di-t-butyl-p-cresol; 2,2-methylenebis(4-ethyl-6 1-t-butylphenol); phenidone; metol; 242-hydroxy-1,1'-binaphthyl; 6,6-dipromo2,2-dihydroxy-1.
1'-binaphthyl; bis(2-hydroxy-1-naphthyl)methane, 2,2-methylenebis-(6-t-butyl-P-cresol), and mixtures thereof. The amount of these reducing agents added is determined appropriately depending on the desired properties of the heat-developable photosensitive material, but it is usually 5 hol or less, preferably 1 molar, per 1 mol of fatty acid silver salt.
It is desirable that the amount is less than 1 mol, most preferably 1 mol to 10-5 mol.

As described above, the constituent components contained in the heat-developable photosensitive material for electrostatic printing master according to the present invention are basically the above-mentioned fatty acid silver salt, an organic acid or a coprecipitated mixture of the fatty acid silver salt, a halide, and a reducing agent. In addition, toning agents are used to control the color tone of the resulting image, stabilizers are used to impart stability to images, which is particularly important during long-term storage, and pre-image forming agents are added. As mentioned above, the organic silver salt layer of the image depends on the so-called fogging prevention due to light during storage of the heat-developable photosensitive material and the fogging after image formation. It is provided by dispersing a coprecipitated mixture of an organic acid or fatty acid silver salt using an appropriate solvent and coating it on a support. As a coating method, for example, a known technique for creating a thin film from a synthetic resin is used. These methods include spin coating by dipping it in an emulsion solution, air knife coating, wire bar coating, and flow coating, and the layer thickness can be adjusted as desired depending on the purpose. It is.

As a binder for dispersing fatty acid silver and an organic acid or a co-mixture of fatty acid silver to form an organic silver salt layer, it has excellent film-forming properties and does not soften beyond the allowable range when thermally developed. It is important not to cause a decrease in binding properties, especially when thermal development is performed using a heated roller, since the binding agent may become softened and the image quality may be disturbed.

Furthermore, during heat development after forming a latent image by image exposure, it does not suppress the release of silver from the fatty acid line salt of the main pot, but rather promotes the release of silver from the fatty acid silver salt in the exposed area. Selection of an effective binder is extremely effective. Furthermore, the heat-developable photosensitive material for electrostatic printing masters must meet the following conditions in addition to the above conditions.

That is, in order to use a heat-developable photosensitive material as an electrostatic printing master, the unexposed area (non-silver image area) and the exposed area ( Since it is based on the electrostatic contrast of the silver image area), it is important that as much static charge as possible is retained in the unexposed areas, and conversely, that as little static charge is retained as possible in the exposed areas. Therefore, it is necessary for the binder to have an electrical resistivity value that is at least capable of holding electrostatic charges. For this reason, Cd is usually used in the electrophotographic field.
Although it is preferable to use a binder having a specific resistance equal to or higher than the specific resistance value of the resin used in a photoreceptor having a photoconductive layer of an S-resin dispersion system or a ZnO-resin dispersion system, this is not necessarily the case. It is not limited.

In other words, fundamentally, as an electrostatic printing master, it is sufficient that the unexposed area has a certain degree of ability to retain static charge, and the electrostatic contrast between the unexposed area and the exposed area is at least at a level suitable for practical use. It is something. Therefore, in order to obtain such electrostatic contrast, the specific resistance value of the non-exposed area and the exposed area of the master must be preferably two orders of magnitude or more higher than the specific resistance of the exposed area. It is desirable to select a binder for a heat-developable photosensitive material that can form an electrostatic printing master having a value of three orders of magnitude or more. The specific resistance of the binder is generally desirably 1 to 30 degrees or higher, preferably 1 to IQ or higher, and most preferably 1 to 30 degrees or higher.

In addition, in order to prevent dielectric breakdown or pinholes from occurring in non-exposed areas during charging, the strength of dielectric breakdown of the binder is determined according to the strength of charging applied by corona discharge, etc. Normally, it is desirable that it be at least 10 KV' side, preferably at least 1 porridge V' side, and optimally at least 2 dishes V/
It is desirable that it be larger than the side. Furthermore, it is also desirable that the binder has excellent moisture absorption resistance.

That is, when an electrostatic printing master is used, for example, in a humid atmosphere, if it lacks moisture absorption resistance, the absorption of moisture in the master causes a decrease in the electrical resistance of non-exposed areas, which causes a decrease in electrostatic contrast. Furthermore, this causes static charges to flow toward the master surface. Therefore, it is necessary to select and determine the degree of moisture absorption resistance of the binder depending on the atmosphere in which the master is used or the region in which it is used (whether or not it is in a humid area, etc.). When the above-mentioned heat-developable photosensitive material is used as a material for forming an electrostatic printing master, the relative humidity is preferably 20 to 100.
% and its equilibrium moisture content is 3.0% or less, optimally 2.0%.
The following is desirable. Representative preferred binders for use in the present invention include polyvinyl butyral, polyvinyl acetate, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, methylcellulose, cellulose propionate, cellulose acetate propionate. pionate, ethyl hydroxycellulose,
Examples include styrene-butadiene copolymer and polymethyl methacrylate, and two or more of these compounds may be used as a mixture if necessary.

Among these binders, for example, if polyvinyl butyral is used, the average degree of polymerization is 500 to 1000, the degree of butyralization is 6 to hol% or less, and the residual acetyl group is 3 hol%.
% or less of polyvinyl butyral is desirable in order to more effectively achieve the object of the present invention.

Furthermore, a plasticizer may be added as necessary.

Examples of the plasticizer include dioctyl phthalate, tricrylsulfophosphate, diphenyl chloride, methylnaphthalene, P-terphenylene, and diphenyl. The amount of these binders is determined as desired, but is usually 0.02 parts by weight of fatty acid silver salt.
Desirably, the amount is from 0.1 to 2 parts by weight, preferably from 0.1 to 5 parts by weight.

Further, as a solvent for dispersing a co-mixture of fatty acid silver and an organic acid or fatty acid silver in a binder, methylene chloride,
Chloroform, ethane dichloride, 1, 1, 2 ethane trichloride, ethylene trichloride, ethane tetrachloride, carbon tetrachloride, 1, 2
Propane chloride, 1.1.1 ethane trichloride, ethylene tetrachloride, ethyl acetate, butyl acetate, isoamyl acetate, cellosolve acetate, toluene, xylene, acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, dimethylamide, N-methylpyrrolidone, methyl alcohol , alcohols such as ethyl alcohol, inpropyl alcohol and butyl alcohol, and water.

Furthermore, the supports used are metal plates such as aluminum, copper, zinc, and silver, metal laminate paper, art paper, paper treated to prevent solvents from entering, paper treated with conductive polymer, and interface. Synthetic resin films mixed with activators, glass or paper with metals, metal oxides, or metal halides adhered to the surface by vapor deposition, synthetic resins, cellulose acetate films, polyethylene terephthalate films, polycarbonate films, polystyrene films, etc. etc. can be used.

Further, insulating glass, paper, synthetic resin, etc. may also be used. In particular, when a heat-developable photosensitive material is used as a forming material for an electrostatic printing master by being wound around a drum as in the present invention, a suitable flexible metal sheet, paper or other conductive material is used to wrap the drum around the drum. It is best to use something that is designed so that it can be wrapped around. Art paper is particularly suitable as such material because of its properties as a support and its low cost.
When providing a conductive layer on the surface of a synthetic resin film, paper, or other non-conductive support, either the organic silver salt layer side of the support or the side opposite to the layer may be selected depending on the purpose of use. When the conductive layer is in direct contact with the organic silver salt layer,
It is preferable to select a material for forming the conductive layer that does not react with the fatty acid silver salt.

When employing a conductive support, it is generally one whose surface resistivity is smaller than the non-silver image area when forming an electrostatic printing master, i.e., less than 1 P.O., preferably 1 and Q.
・Any material may be used as long as it is below the standard and does not react with the fatty acid silver salt.

In order to form an electrostatic printing master using the heat-developable photosensitive material for electrostatic printing master of the present invention, image exposure is usually required in a structure in which a reducing agent layer is provided on an organic silver salt layer. A latent image is formed thereon and then thermally developed to form a silver image as a master.

In addition, in the case of a heat-developable photosensitive material that does not contain a reducing agent in advance, an electrostatic printing master is formed by adding a reducing agent before or after image exposure, forming a latent image, and performing heat development. . The reducing agent may be added by immersing the heat-developable photosensitive material before image exposure in a liquid containing the reducing agent at the time of use, or by adding the reducing agent before image exposure. A reducing agent may be added in a similar manner before post-thermal development. Alternatively, instead of the above-mentioned impregnating method, a reducing agent solution dispersed in cellulose acetate or the like can be applied to the organic silver salt layer by brushing, coating, doctor blade, spraying, etc. using an appropriate solvent. Also good. It is advantageous if the reducing agent layer is peeled off from the surface of the organic silver salt layer after heat development, since so-called fogging due to the action of the remaining reducing agent can be prevented. Note that the use of the heat-developable photosensitive material for electrostatic printing masters of the present invention is not limited to electrostatic printing masters, but it can also be used for conventional image exposure and thermal development to obtain visible images. It can also be used as a heat-developable photosensitive material for copying paper or other photosensitive recording materials.

Hereinafter, the present invention will be specifically explained with reference to Examples.

[Sample preparation and evaluation of silver images]

Sample 1: 8 hol% silver behenate*125 times, toluene at 120 times, and methyl ethyl ketone at 120 times were mixed and dispersed for more than 7 hours by a ball milling method.

Thereafter, 60 minutes of polyvinyl butyral BM-1*2 (20% 9% ethyl alcohol solution) and 40 hours of ethyl alcohol were added and thoroughly mixed to prepare a polymer dispersion of an organic silver salt.

The thus prepared polymer dispersion was added with 9 parts of 120 parts of mercury acetate.
/25 [Methyl alcohol solution, calcium bromide 20
3/25 of 0 [Methyl alcohol solution, Phthazinone 2
．． 5 minutes were added and further mixing was performed. Next, this polymer dispersion was coated onto art paper using a coating rod so that the film thickness after drying would be 8 mounds, thereby forming an organic silver salt layer. Next, separately 2,2-methylene bis(6-t
-butyl p-cresol) 1.5 yen, phthalazinone o
．． 3 nights, 10 nights of cellulose acetate L-30** (1 skin t% acetone solution) and 30 nights of acetone were mixed to prepare an overcoat layer solution.

Z This overcoat layer solution was coated on the organic silver salt layer at a drying point so that the film thickness after drying was 4 μm to obtain a heat-developable photosensitive material. *1 8 enemy hol
% silver behenate means the number of moles of silver salt of an organic acid.
Divide by the sum of the ol number and the mol number of the silver salt of organic acid,
Regarding the silver salt of an organic acid having a ratio that is 100 times that value, it means the case where the silver salt of the organic acid is silver behenate.

The mol% of the organic acid silver salt in the following samples shall have the above meaning. *2 BM-1 (product name: Sekisui Chemical Co., Ltd., Eslec B); average degree of polymerization 500 to 10
00, degree of butyralization 620 $hol%, residual acetyl group 3hol% or less** L-30 (product name: L-AC manufactured by Daicel Corporation); average degree of polymerization 150, degree of acetylation 55%) The above-mentioned heat-developable photosensitive The material is tungsten light source (25001
After that, the sand was exposed to light at a temperature of about 2 using a roller heat developer at about 130 qo for about 5 seconds, and the maximum blackened reflection density and fog density of this visible image were The reflection density produced when the unexposed area was heated was measured.

As a result, the maximum reflective blackening density was 1. & Fog density is 0
．． 12, giving a very clear and pure black visible image,
It was recognized that the photosensitive material was impractical. Sample 2 Organic silver salt layer-forming composition A and topcoat layer-forming composition B shown below were prepared according to the procedure of Sample 1, and composition A
and Composition B were coated on art paper in the same manner as Sample 1 to obtain a heat-developable photosensitive material.

Composition A: 9 melon hol% silver behenate ethyl ethyl ketone 120 toluene 1
20 Polyvinyl Ptyral BM-1 (1 t% ethyl alcohol solution) 100 Mercury acetate 120 m9 Calcium bromide 200 Female phthalazinone
2.5 composition B: 2.2-
Methylene-pis-(6-t-butyl-p-cresol)
1.5 ta cellulose acetate L-30 (1
Hada t% Aceton Clan) 10th evening Acetoso
30 3.3-diethylene-2.2-thiacarbocyanine iodide 8 MisakiThe light-sensitive material in this sample was also heat-developed in the same machine as sample 1, but the exposure time was 3 seconds and the development time was 2 seconds.

The maximum blackening reflection density (Dmax) of the obtained image was 1.9
The fog density (Dmin) was 0.24. The fog density was mostly contributed by the coloring of the dye itself. Therefore, it was confirmed that the heat-developable photosensitive material in this publication is also a highly practical photosensitive material, similar to Sample 1. Samples 3-1 to 3-4 Samples 3-1 to 3-4 were prepared in exactly the same manner as Sample 1 except that the 9-mark hol% silver behenate in Sample 2 was replaced with the compound {1} in Table 1. As sample 4, the same measurements as sample 2 were performed, and the results shown in Table 2 were obtained.
Samples Nos. 1 to 3-4 were also found to be excellent heat-developable photosensitive materials similar to Sample 2.

Samples 4-1 and 4-2 Compound ■ in Table 1 instead of silver behenate in Sample 2
, [61], and the amount of 2,2-methylene-bis(6-t-butyl-p-cresol) of composition B added is 1.
Sample 4 was prepared in exactly the same manner as sample 2 except that 59 was replaced by 1.
-1 and 4-2.

Next, this sample was further subjected to the same measurements as Sample 2, and similar to Sample 2, good results were obtained as shown in Table 2, indicating that Samples 4-1 and 4-2 are excellent heat-developable photosensitive materials. This was recognized. Samples 5-1 to 5-3 Compounds in Table 1 were substituted for silver behenate in Sample 2 [
7}, [8}, '9), and the addition amount of 2,2-methylenebis(6-t-butyl-p-cresol) of composition B was changed from 1.5 to 0.7, but the same as sample 2 was used. Samples 5-1 to 5-3 were prepared in the same manner.

Next, this sample was subjected to the same measurements as Sample 2), and as with Sample 2, good results were obtained as shown in Table 2, indicating that Samples 5-1 to 5-3 are excellent heat-developable photosensitive materials. Admitted. Table 1 Table 2 Sample 6 Organic silver salt layer-forming composition A and overcoat layer-forming composition B shown below were prepared according to the procedure of Sample 1, and composition A
and Composition B were coated on art paper in the same manner as Sample 1 to obtain a heat-developable photosensitive material.

Composition A: 9 hol% silver behenate
25 methyl ethyl ketone 1
20 Tatleen 12
0% polyvinyl butyral BM-4* (1% W% ethyl alcohol solution) 100% mercury acetate
120 female calcium bromide
200 9 phthalazinone
2.5ta composition B: 2.2'
-methylene-pis-(6-t-butyl-p-cresol) 1.5 t-cellulose acetate L-30 (
1 skin t% acetone solution)
10 evening acetone 30
3.3-diethyl-2.2-thiacarboxyanine iodide 8 The photosensitive material in the sample was also heat developed in the same manner as sample 1, but the exposure time was 3 seconds and the development time was 2 seconds.

The maximum blackening reflection density (Dmax) of the obtained image was 1.8
The fog density (Dmin) was 0.22. The fog density was mostly contributed by the coloring of the dye itself. Therefore, it was confirmed that the heat-processable photosensitive material in this sample was also a photosensitive material with the same excellent practicality as sample 1. *B
M-4 (Product name: Sekisui Chemical k.k) Average degree of polymerization 50
0 to 1000 Degree of butyralization 62 ± hol% Residual acetyl group 4 to 8 hol% Samples 7-1 to 7-6 Except for replacing BM-4, the binder in sample 6, with compound '10 to 03 in Table 3 When samples 7-1 to 7-6 were measured in exactly the same manner as sample 6, the results shown in Table 4 were obtained.
It was also confirmed that Sample 7-6 was a heat-developable photosensitive material produced on the same machine as Sample 2.

Table 3 Table 4 Rice BMS (Product Name: Sekisui Chemical K.K) Average degree of polymerization 700-800' Butyralization degree 67 mo or more Residual acetyl group 4-6 moZ Rice Rice BH-1 (Product name: Sekisui Chemical industry k.k) Average degree of polymerization 1000-2000' Degree of butyralization 623 Residual acetyl group 3 mos or less Sample 8 9 hol% Behenic acid 25 moss, Methyl ethyl ketone 12
After 1 hour, 120 minutes of toluene was mixed and dispersed for more than 7 hours using a ball milling method.

After that, polyvinyl butyral BM-1 (2 t%
Dioxane solution) for 50 minutes and cellulose acetate (1% dioxane solution) for 20 hours were added and further mixed to prepare a polymer dispersion of an organic silver salt.

Mercury acetate 120 female was added to the polymer dispersion thus prepared.
200 parts of calcium bromide and 2.5 parts of phthalazinone were mixed to prepare an organic silver salt layer forming solution. This solution was applied onto art paper in the same manner as Sample 1 to form an organic silver salt layer.
Separately, a solution of the same type as Composition B of Sample 2 was prepared as an overcoat layer solution and coated on the organic silver salt layer in the same manner as Sample 1 to obtain a heat-developable photosensitive material.

Next, this photosensitive material was also measured in exactly the same way as Sample 2, and Dmax=1.8 Dmino. Similar to Sample No. 26 and Sample 2, very good results were obtained, and it was recognized that the photosensitive material of this sample was also excellent like Sample 2. Sample 9 Organic silver salt layer-forming composition A and topcoat layer-forming composition B shown below were prepared according to the procedure of Sample 1, and composition A
and Composition B were coated on art paper in the same manner as Sample 1 to obtain a heat-developable photosensitive material.

Composition A: 7 hol% silver behenate
25 methyl ethyl ketone 1
20 Tatleen 12
Ethylene-acetate copolymer (5M% toluene solution)
150 mercury acetate 120
Calcium bromide 9 of 200
Phthalazinone 2.5% Composition B: 2,2-methylene-bis(6-t-butyl-
p-cresol) 1.5 t Cellulose acetate L-30 (1 t% acetone solution)
10th night acetone
The light-sensitive materials in the nine samples of 3023.3-diethyl-2.2-thiacarbocyanine iodide 8 were also heat-developed in the same manner as Sample 1, but the exposure time was 3 seconds and the development time was 2 seconds.

The maximum blackening reflection density (Dmax) of the obtained image was 1.8
The fog density (Dmin) was 0.26. The fog density was mostly contributed by the coloring of the dye itself. Therefore, it was confirmed that the heat-developable photosensitive material in this sample was also a highly practical photosensitive material similar to Sample 1. Sample 10 9 h instead of 7 hol% silver behenate in sample 9
Sample 9 was carried out in the same manner as Sample 9, except that 0.1% silver stearate was used and 2,2-methylene-bis(6-t-butyl-p-cresol) was used at 0.8 m instead of 1.5 m. When a developable photosensitive material was produced, good results were obtained.

Sample 11 In place of the ethylene-acetate copolymer in Sample 10, terbene resin (1% butyl acetate solution) was used in the same manner as in Sample 10, and an excellent heat-developable photosensitive material was obtained. Ta.

Sample 12 80% silver laurate was used instead of the 7% hol% silver behenate of sample 9, and 0% was used instead of 2,2'-methylene-bis(6-t-butyl-p-cresol) 1.5%. .5
An excellent heat-developable photosensitive material was obtained when the same procedure as Sample 9 was carried out except that the sample was prepared using the following materials.

Sample 13 The same process as Sample 12 was used except that Compound 02 was used in place of the ethylene-vinyl acetate copolymer in Sample 12, and an excellent heat-developable photosensitive material was obtained.

Sample 14 9% hol% silver behenate 25%, stearic acid 10%,
120 minutes of toluene and 120 hours of methyl ethyl ketone were mixed and dispersed for more than 7 hours using a ball milling method.

After that, polyvinyl butyral BM-1 (1 skin t%
Add 100 ml of ethyl alcohol solution and mix further.
A polymer dispersion of an organic acid silver salt was prepared. To the polymer dispersion thus prepared were added 120 parts of mercuric acetate, 200 parts of calcium bromide, and 2.5 parts of phthalazinone to prepare an organic silver salt layer forming solution. The organic silver salt layer forming solution thus prepared was coated on art paper in the same manner as Sample 1, and Composition B of Sample 2 was further coated on the organic silver salt layer to obtain a heat-developable photosensitive material. Next, the characteristics of this photosensitive material were measured in the same manner as Sample 2, and it was found to be a photosensitive material with excellent phenomenal properties and image properties.

Sample 15 When the same procedure as Sample 14 was carried out using 8 hol% silver behenate instead of 90 hol% silver behenate and lauric acid instead of stearic acid, good heat developability was obtained. A light material was obtained.

Samples 16-1 to 16-5 As shown in Table 5, these samples were examined for the mixing ratio of fatty acid silver salt and binder.
Regarding 11 to 16-5, sample 16-1 is sample 2, samples 16-2, 16-3 are sample 1, samples 16-4, 16-5
When the same measurements as Sample 4 were carried out, it was found that Samples 16-1 to 16-5 were all excellent heat-developable photosensitive materials.

Table 5 Rice 1: Usage amount is 25g for each fatty acid silver salt Rice 2: Prescription for each sample Sample 16-1: Replace the binder in Sample 2 with the binder in Table 5.

Samples 16-2 and 16-3: The binders in Sample 1 were replaced with the binders listed in Table 5, and ethyl alcohol 40% was further removed.

Samples 16-4 and 16-5: The binder in Sample 4 was replaced with the sample binder in Table 5, respectively.

The formulations for each sample were the same as in each example except that the type of fatty acid silver and the type of binder were changed.

Samples 17-1 and 17-2 Cellulose acetate L-30 in sample 2 was replaced with LM-70* and LT-80**,
The rest was carried out in the same manner as Sample 2. Heat-developable photosensitive material Sample 17
When samples No. 11 and No. 17-2 were prepared and the same measurements as Sample 2 were performed, good results similar to Sample 2 were obtained.

*LM-70 (product name: Daicel k.k) acetylation degree 53
% Average degree of polymerization 180 (1 skin t% aceto r solution) **
LT-80 (Product name: Daicel k.k) Acetylation degree 61%
Average degree of polymerization 280 (1 t% methylene chloride:methanol (9:1)) Example 1 The following study was conducted to determine whether the heat-developable photosensitive material of Sample 1 could be used as a master for electrostatic printing.

A tungsten beam (25
After exposure of 2M paper using 00lux), a negative printed visible image was obtained by heating and developing for 130cm05 seconds using a roller type heating device, and was used as a master for electrostatic printing.

Next, after uniformly applying a corona discharge of 17 KV to the electrostatic printing master, the negatively charged toner was developed by a magnetic brush development method, and a positive toner image was obtained. When a transfer paper was placed over this toner image and the aforementioned corona discharge was applied from the transfer paper side, a clear transferred visible image was obtained. Even after repeating this charging and development transfer for 1000 times or more, no deterioration was observed on the surface of the master, and no deterioration in the quality of the transferred image was observed. As a result, it was recognized that this was an excellent master for repeated printing. Furthermore, since the silver image exhibits faithful reproducibility with respect to the original image, it was observed that an electrostatic image corresponding to the original image was formed, and the toner image also became a faithful photographic image.

When we measured the electrostatic properties of this master for electrostatic printing, we found that the charging potential difference (electrostatic contrast) between the image area (silver image area) and the non-image area (non-silver image area) was 380V, and the remaining It turns out that the potential is very small. Next, the maximum blackening density (Dmax) of the image area of the master was measured and found to be 1.8. Furthermore, when the blackening density (fog density) of the non-image area on the transfer paper with the transferred image was measured, it was found to be a very small value of 0.13. From the above measurements,
It has been revealed that the heat-developable photosensitive material in Sample 1 has a very clear transferred visible image on the transfer paper, has excellent image quality with no overlap, and forms a master for electrostatic printing with excellent rigidity resistance. .

Therefore, it was confirmed that the heat-developable photosensitive material of Sample 1 is an extremely excellent photosensitive material that provides a master for electrostatic printing, and can be used as a heat-developable photosensitive material for forming an electrostatic printing master.

Example 2 Terbene resin (
A heat-developable photosensitive material was prepared in the same manner as Sample 2 except that the same amount of 1% butyl solution was used.

Next, the same study as in Example 1 was conducted, and it was found that the photosensitive material also had excellent properties as a heat-developable photosensitive material for forming an electrostatic printing master. Example
3 For each of the heat-developable photosensitive materials from Sample 2 to Sample 17-2, it was examined whether each photosensitive material using the same machine as Example 1 could be used as a master for electrostatic printing.

As a result, each of the heat-developable photosensitive materials from Sample 2 to Sample 17-2 had excellent image quality and printing durability, as well as various properties required as a master for electrostatic printing, as in Example 1. It became clear that it would give a master who has enough. From the above, each heat-developable photosensitive material from Sample 2 to Sample 17-2 has characteristics as a heat-developable photosensitive material for forming an electrostatic printing master, and is an excellent material for electrostatic printing that can withstand practical use. It became clear that a master was formed.

Claims (1)

[Claims] 1 mol% of fatty acid silver salt based on the total mol of fatty acid silver salt and organic acid, based on 1 part by weight of the fatty acid silver salt, the main components are fatty acid silver salt, organic acid, and halide, which is 10 mol% or more. The amount of binder is 0.02 to 20 parts by weight, and the specific resistance is 10^1^0Ωcm or more and 10K.
For use as an electrostatic printing master, characterized in that it has a dielectric breakdown strength of V/mm or more and is dispersed in a binder whose equilibrium moisture content is 3.0% or less at a relative temperature of 20 to 100%. heat-developable photosensitive material.