DE69525428T2 - Heat-developable light-sensitive color material - Google Patents

Description

The present invention relates to a heat-developable color photosensitive material. More particularly, the present invention relates to a heat-developable color photosensitive material on which image data generated by electric signals can be recorded by means of a light-emitting element to form a stable image. Furthermore, the present invention relates to a heat-developable color photosensitive material which has a minimized change in image density against the change in processing temperature during heat development and a minimized change in image color balance against the change in environmental conditions (particularly temperature) during exposure and gives an image having an excellent distinction between image area and non-image area.

A heat-developable, light-sensitive color material is known in the art. For example, in Shashin Kogaku no Kiso (Fundamentals of Photographic Technology, Non-Silver Salt System Photography Edition, published by Corona Co., 1982, pages 242 to 255) and in US Patent 4,500,626, heat-developable, light-sensitive materials and methods therefor are described.

DE-A-35 26 315 describes a heat-developable, photosensitive material which contains a support with a photosensitive layer thereon, the photosensitive layer containing a photosensitive silver halide, silver salt grains with a solubility inhibitor adsorbed thereon, a reducing agent and a binder.

Furthermore, US patents 3,761,270 and 4,021,240 describe a process which comprises the coupling reaction of an oxidation product of a developing agent with a coupler to form a dye image. US patent 4,235,957 also describes a process which comprises bleaching a light-sensitive silver dye to form a positive color image.

Recently, a method has been proposed which comprises allowing imagewise release and formation of a diffusible dye by heat development and then transferring the diffusible dye to a dye fixing element. In this method, both negative and positive dye images can be obtained by changing the kind of dye-yielding compounds used or the kind of silver halides used. Specifically, this method is described in U.S. Patents 4,500,626, 4,483,914, 4,503,137 and 4,559,290, in JP-A-58-149046 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-60-133449, JP-A-59-218443 and JP-A-61-238056, in EP-A-220746 and EP-A-210660 and in JIII Journal of Technical Disclosure 87-6199.

Numerous methods have been proposed for obtaining a positive color image by heat development. For example, U.S. Patent 4,559,290 describes a method which comprises co-existing a reducing agent or a precursor thereof with an oxidized DRR compound which has no ability to release a dye image, oxidizing the reducing agent in accordance with exposure of the silver halide by heat development, and reducing the oxidized DDR compound to release a non-diffusible dye. Furthermore, EP-A-220746 and JIII Journal of Technical Disclosure 87-6199 (Vol. 12, No. 22) describe a heat-developable color photosensitive material using a compound which releases a non-diffusible dye by reductive cleavage of an N-X bond (wherein X represents an oxygen atom, nitrogen atom or sulfur atom) according to a similar mechanism as mentioned above.

In general, conventional color photosensitive materials have been spectrally sensitized to blue, green and red colors. In order to record image data converted into an electric signal on such a color photosensitive material, a color CRT (cathode ray tube) is usually used as a light source for exposure. However, CRT is unsuitable for giving a large-format print.

As print heads capable of producing large-format printing, light-emitting diodes (LEDs) and semiconductor lasers (LDs) have been developed. However, no print heads capable of performing effective emission of blue light have been developed.

Accordingly, if light emitting diodes are used, it is necessary that three light emitting diodes, i.e., a near infrared LED (800 nm), a red LED (670 nm) and a yellow LED (570 nm) are combined to provide a light source with which to expose a color photosensitive material having three layers spectrally sensitized to the near infrared, red and yellow regions, respectively. An image recording system having such a mechanism is described in Nikkei New Material, September 14, 1987, pages 47 to 57. Some systems have been put into practical use.

Furthermore, JP-A-61-137149 describes a system comprising three semiconductor lasers emitting light of 880 nm, 820 nm and 760 nm in combination to form a light source with which a color photosensitive material having three photosensitive layers having spectral sensitivity for the respective wavelength ranges is exposed to light to perform recording.

When a multilayer color photosensitive material is used which is adapted to be exposed to three different spectral regions to develop three colors, i.e. yellow, magenta and cyan, it is usually an important technique for color reproduction to develop these colors without discoloring colors. When LED or LD is used as a light source for exposure, the photosensitive material must be designed to provide the three spectral sensitivities in a narrow spectral region (i.e. from the short wavelength side of the red region to the infrared region). How to minimize the overlap of these spectral sensitivities is therefore essential to improving color separability.

As techniques for ensuring color separability, a technique is known which increases the sensitivity to the short-wave side and provides a filter layer as described in US Patent 4,619,892. The increase in sensitivity to however, the short-wave side is disadvantageous in that fog is formed and aging stability is deteriorated. Accordingly, in infrared sensitization, high sensitivity can hardly be obtained due to deserisitization caused by the addition of a dye or low efficiency of color sensitization.

To solve these problems, JP-A-4-146431 and JP-A-5-45828 describe a color photosensitive material comprising a J-band type infrared sensitizing dye having a sharp spectral sensitivity to give good color separation, high sensitivity and good storage stability.

However, the heat-developable color photosensitive material comprising such a J-band type infrared sensitizing dye is disadvantageous in that the obtained image tends to undergo a large change in color tone under certain environmental conditions, particularly temperature, during exposure.

It is therefore an object of the present invention to provide a heat-developable, light-sensitive color material which comprises at least two silver halide emulsion layers having a spectral sensitivity peak in different wavelength ranges of 700 nm or more, which shows a smaller change in image density against the change in processing temperature during heat development, a smaller change in image color balance against the change in environmental conditions, in particular the temperature, during exposure and an excellent discrimination between the image area and the non-image area.

This object of the present invention has been achieved by a heat-developable, light-sensitive color material with a support on which at least two light-sensitive silver halide layers with a spectral sensitivity peak in a different wavelength range of 700 nm or more are provided, in which the at least two light-sensitive silver halide layers are each combined with a compound which produces a dye with a different color tone, wherein the layer with a spectral sensitivity peak in the longest wavelength and/or a light-insensitive intermediate layer adapted thereto further (a) a high silver chloride emulsion of fine grains having a silver chloride content of 80 mol% or more and an average size of 0.15 µm or less, or (b) a readily soluble silver salt compound.

The change in color balance (ΔCB) versus the change in exposure conditions used herein is largest in the yellow, magenta and cyan density differences and can be defined by the following equation:

ΔCB = MAX[ΔCBYM, ΔCBMC, ΔCBCY]

where MAX[X] represents the maximum value. Assuming that the yellow, magenta and cyan gradations are γY, γM and γc, respectively, and the change in the yellow, magenta and cyan sensitivity according to the change in the exposure temperature are ΔSY, ΔSM and ΔSC, respectively, ΔCBYM, ΔCBMC and ΔCBCY can be defined by the following equations:

ΔCBYM = ΔSYXγY - ΔSMXγM (absolute value)

ΔCBMC = ΔSMXγM - ΔSCXγC (absolute value)

ΔCBCY = ΔSCXγC - ΔSYXγY (absolute value);

provided that the gradation γY is the difference between EY,1,0 and EY,0,5, which are the exposures (logarithm) required to obtain densities of 1.0 and 0.5 respectively at 25ºC and 50% relative humidity, and can be defined as follows (γM and γC are defined similarly):

γY = (1.0 - 0.5)/(EY,1.0 - EY0.5)

γM = (1.0 - 0.5)/(EM,1.0 - EM0.5)

γC = (1.0 - 0.5)/(EC1.0 - EC0.5)

ΔSy is the difference between Sy,30 and SY,15, which are the sensitivities that appear when the exposure is at 30ºC and 50% relative humidity or at 15ºC and 50% relative humidity, and can be defined as follows (ΔSM and ΔSc are defined similarly):

ΔSy = Sy,30 - SY,15

ΔSM = SM,30 - SM,15

ΔSC = SC,30 - SC,15

Sensitivity, as used herein, is defined as the reciprocal of the exposure (logarithm) required to obtain a density of 0.75.

Preferably, in the heat-developable color photosensitive material of the present invention, the compound which gives a dye (hereinafter referred to as a dye-providing compound) combined with the layer having a spectral sensitivity peak in the longest wavelength is a compound represented by the following formula (1):

wherein Dye represents a dye group or dye precursor group represented by the following formula (2), Y represents a group which makes a difference in the diffusibility of the dye component in accordance or in opposition to a reduction reaction of photosensitive silver halide having an imagewise latent image to silver; X represents a single bond or a bonding group; p is an integer of 1 or more; and q is 1 or 2, with the proviso that when p is 2 or more, or q is 2, the plural dye groups or ((Dye)p - X) groups may be the same or different:

wherein R³ represents a substituent selected from the group consisting of a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, an alkyl group, an aralkyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an amino group, an acylamino group, a sulfonylamino group, an acyl group, a sulfonyl group, a carbamoyl group, a sulfamoyl group, a ureido group, an alkylthio group and an arylthio group; R¹ and R² each independently represent a hydrogen atom or the substituent defined in R³, and R¹ and R² may be the same or different from R³; and n is an integer from 0 to 5, with the proviso that when n is 2 to 5, the plural R³ groups may be the same or different; and Dye and X are bonded to each other to any of R¹, R² and R³.

The spectral sensitivity peak in the layers of the heat-developable, photosensitive color material lies within a wavelength range of 700 nm or more, preferably from 700 to 1200 nm.

The high silver chloride fine grain emulsion for use in the present invention can be prepared in the same manner as in the preparation of the silver halide emulsion described later. The silver chloride content is 80 mol% or more, preferably 90 mol% or more. The average size of the grains is preferably less than 0.115 µm, more preferably 0.01 to 0.10 µm.

Examples of the easily soluble silver salt compound include silver nitrate, silver fluoride, silver perchlorate, silver hexafluorophosphate(V) and potassium dicyanargentate(I). Among them, silver nitrate and silver fluoride are preferred.

The added amount of the high silver chloride fine grain emulsion or the easily soluble silver salt compound is preferably 5 mg/m² to 100 mg/m², more preferably 10 mg/m² to 60 mg/m², in terms of silver.

The high silver chloride fine grain emulsion or the easily soluble silver salt compound is incorporated in at least one layer of the layer having a spectral sensitivity peak in the longest wavelength and the adjacent non-photosensitive intermediate layer(s). As a result, an effect minimizing variations in heat development and variations in color balance against the change in temperature conditions during exposure. Such an effect is usually more remarkable than expected. Such an effect is probably inherent in heat-developable color photosensitive materials. The detailed principle of this effect is not known at present. This effect is more remarkable in combination with the dye-providing compound represented by the formula (1). Such combined use of the above-described emulsion or the easily soluble silver salt compound and the above-described dye-providing compound is preferred because the excellent properties of the dye-providing compound can be obtained.

The compound represented by formula (1) for use in the present invention is further described below.

First, X will be described further.

X represents a single bond or a bonding group. Examples of the bonding group represented by X include an alkylene group, a substituted alkylene group, an arylene group, a substituted arylene group, a heterocyclic group, -O-, -SO2-, -CO-, -NR14- (wherein R10 represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group), and bonding groups formed by combining two or more of these groups.

Preferred examples of this bonding group represented by X include -NR¹⁴SO₂-, -NR¹⁴CO-, -O-, -SO₂-, and groups formed by combining these groups with a substituted or unsubstituted alkylene group (e.g., methylene, ethylene, propylene) or arylene group (e.g., o-phenylene, m-phenylene, p-phenylene, 1,4-naphthylene).

If X has one or more substituents, preferred examples of the substituents include the following:

an alkyl group that can be substituted (e.g. methyl, trifluoromethyl, chloromethyl, dimethylaminomethyl, ethoxycarbonylmethyl, aminomethyl, acetylaminomethyl, ethyl, carboxyethyl, 3,3,3-trichloropropyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, sec-pentyl, t-pentyl, cyclopentyl, n-hexyl, sec-hexyl, t-hexyl, cyclohexyl, n-octyl, sec-octyl, t-octyl, n- Decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, sec-hexadecyl, t-hexadecyl, n-octadecyl, t-octadecyl),

an aralkyl group which may be substituted (e.g. benzyl),

an alkenyl group which may be substituted (e.g. vinyl, allyl, 2-chlorovinyl, 1-methylvinyl, 2-cyanovinyl, cyclohexen-1-yl),

an alkynyl group which may be substituted (e.g. ethynyl, 1-propenyl, 2-ethoxycarbonylethynyl),

an aryl group which may be substituted (e.g. phenyl, naphthyl, 3-hydroxyphenyl, 3-chlorophenyl, 4-acetylaminophenyl, 2-methanesulfonyl-4-nitrophenyl, 3-nitrophenyl, 4-methoxyphenyl, 4-acetylaminophenyl, 4- methanesulfonylphenyl, 2,4-dimethylphenyl),

a heterocyclic group which may be substituted (e.g. 1-imidazolyl, 2-furyl, 2-pyridyl, 5-nitro-2-pyridyl, 3-pyridyl, 3,5-dicyano-2-pyridyl, 5-tetrazolyl, 5-phenyl-1- tetrazolyl, 2-benzthiazolyl, 2-benzimidazolyl, 2-benzoxazolyl, 2-oxazolin-2-yl, morpholino),

an acyl group which may be substituted (e.g. acetyl, propionyl, butyloyl, isobutyloyl, 2,2-dimethylpropionyl, benzoyl, 3,4-dichlorobenzoyl, 3-acetylamino-4-methoxybenzoyl, 4-methylbenzoyl, 4-methoxy-3-sulfobenzoyl),

a sulfonyl group which may be substituted (e.g. methanesulfonyl, ethanesulfonyl, chloromethanesulfonyl, propanesulfonyl, butanesulforiyl, benzenesulfonyl, 4-toluenesulfonyl),

a carbamoyl group which may be substituted (e.g. carbamoyl, methylcarbamoyl, dimethylcarbamoyl, bis-(2-methoxyethyl)carbamoyl, dimethylcarbamoyl, cyclohexylcarbamoyl),

a sulfamoyl group which may be substituted (e.g. sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, diethylsulfamoyl, bis-(2-methoxyethyl)sulfamoyl, di-n-butylsulfamoyl, 3-ethoxypropylmethylsulfamoyl, N-phenyl-N-methylsulfamoyl),

an alkoxycarbonyl or aryloxycarbonyl group which may be substituted (e.g. methoxycarbonyl, ethoxycarbonyl, phenoxycarbonyl, 2-methoxyethoxycarbonyl),

an alkoxysulfonyl or aryloxysulfonyl group which may be substituted (e.g. methoxysulfonyl, ethoxysulfonyl, phenoxysulfonyl, 2-methyloxyethoxysulfonyl),

an alkoxy or aryloxy group which may be substituted (e.g. methoxy, ethoxy, methoxyethoxy, 2-chloroethoxy, phenoxy, p-methoxyphenoxy),

an alkylthio or arylthio group which may be substituted (e.g. methylthio, ethylthio, n-butylthio, phenylthio, 4-chlorophenylthio, 2-methoxyphenylthio),

an amino group which may be substituted (e.g. amino, methylamino, N,N-dimethoxyethoxyamino, methylphenylamino),

an ammonio group which may be substituted (e.g. ammonio, trimethylammonio, phenyldimethylammonio, dimethylbenzylammonio),

an acylamino group which may be substituted (e.g. acetylamino, 2-carboxybenzoylamino, 3-nitrobenzoylamino, 3-diethylaminopropanoylamino, acryloylamino),

an acyloxy group which may be substituted (e.g. acetoxy, benzoyloxy, 2-butenoyloxy, 2-methylpropanoyloxy),

a sulfonylamino group which may be substituted (e.g. methanesulfonylamino, benzenesulfonylamino, 2-methoxy-5-n-methylbenzenesulfonylamino),

an alkoxycarbonylamino group which may be substituted (e.g. methoxycarbonylamino, 2-methoxyethoxycarbonylamino, isobutoxycarbonylamino, benzyloxycarbonylamino, t-butoxycarbonylamino, 2-cyaneethoxycarbonylamino),

an aryloxycarbonylamino group which may be substituted (e.g. phenoxycarbonylamino, 2,4-nitrophenoxycarbonylamino),

an alkoxycarbonyloxy group which may be substituted (e.g. methoxycarbonyloxy, t-butoxycarbonyloxy, 2-benzenesulfonylethoxycarbonyloxy, benzylcarbonyloxy),

an aryloxycarbonyloxy group which may be substituted (e.g. phenoxycarbonyloxy, 3-cyanophenoxycarbonyloxy, 4-acetoxyphenoxycarbonyloxy, 4-t-butoxycarbonylaminophenoxycarbonyloxy),

an aminocarbonylamino group which may be substituted (e.g. methylaminocarbonylamino, morpholinocarbonylamino, N-ethyl-N-phenylaminocarbonylamino, 4-methanesulfonylaminocarbonylamino),

an aminocarbonyloxy group which may be substituted (e.g. dimethylaminocarbonyloxy, pyrrolidinocarbonyloxy, 4-dipropylaminophenylaminocarbonyloxy),

an aminosulfonylamino group which may be substituted (e.g. diethylaminosulfonylamino, di-n-butylaminosulfonylamino, phenylaminosulfonylamino),

a sulfonyloxy group which may be substituted (e.g. phenylsulfonyloxy, methanesulfonyloxy, chloromethanesulfonyloxy, 4-chlorophenylsulfonyloxy),

a carboxyl group, a sulfo group, a cyano group, a nitro group, a hydroxyl group and a halogen atom.

Among these, particularly preferred are an alkoxy group, an amino group, a sulfamoyl group, a sulfonylamino group, a carboxyl group, a sulfo group and a halogen atom.

These substituents can be used as substituents on other substituents described below in the present invention.

Y is further described below. The following formulas are described including X.

(1) Y comprises a negative working release agent which releases a photographically usable group in accordance with development.

Examples of Y include a negative working release agent which releases a photographically useful group from an oxidation product.

A preferred example thereof includes a compound represented by the following formula (Y-1):

wherein β represents a non-metallic atom group necessary for forming a benzene ring, and the benzene ring may be condensed with a saturated or unsaturated carbon ring or a heterocyclic ring; α represents -OZ² or -NHZ³, wherein Z² represents a hydrogen atom or a group capable of producing a hydroxyl group by hydrolysis, and Z³ represents a hydrogen atom, an alkyl group, an aryl group or a group capable of producing an amino group by hydrolysis; Z¹ represents a halogen atom, a cyano group, an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an alkylthio group, an aryloxy group, an arylthio group, an acyl group, a sulfonyl group, an acylamino group, a sulfonylamino group, a carbamoyl group, a sulfamoyl group, a ureido group, a urethane group or a heterocyclic group, each of which may have substituents; a is an integer of 1 or more, provided that when a is 2 or more, the plural Z¹ groups are the same or may be different; -G means -NHSO₂X; and X has the same meaning as defined in formula (1).

Preferred among the groups represented by the formula (Y-1) are those represented by the following formulas (Y-2) and (Y-3):

wherein Z² and G each have the same meaning as defined in the formula (Y-1); and Z⁵ and Z⁵ each independently represent an alkyl group, an aryl group or an aralkyl group, each of which may have one or more substituents.

Preferably, Z⁵ is a secondary or tertiary alkyl group, and the sum of the number of carbon atoms contained in Z⁵ and Z⁵ is 20 to 50.

Specific examples of these groups represented in formulas (Y-2) and (Y-3) are disclosed in U.S. Patents 4,055,428 and 4,336,322, JP-A-51-113624, JP-A-56-16131, JP-A-56-71061, JP-A-56-71060, JP-A-56-71072, JP-A-56-73057, JP-A-57-650, JP-A-57-4043, JP-A-59-60439, JP-B-56-17656 (the term "JP-B" as used herein means an "examined Japanese patent publication") and JP-B-60-25780. described.

Another example of Y is (Y-4):

wherein α, G, Z¹ and a have the same meaning as defined in the formula (Y-1), respectively; β' represents a non-metallic atom group necessary for forming a benzene ring, and the benzene ring may be condensed with a saturated or unsaturated carbon ring or heterocyclic ring.

Preferably, in the formula (Y-4), α is -OZ², and β' forms a naphthalene skeleton. Specific examples thereof are described in U.S. Patent Nos. 3,928,312 and 4,135,929.

Examples of the releaser which releases a photographically useful group in a similar reaction as in (Y-1) and (Y-2) include those described in JP-A-51-104343, JP-A-53-46730, JP-A-54-130122, JP-A-57-85055, JP-A-53-3819, JP-A-54-48534, JP-A-49-64436, JP-A-57-20735, JP-B-48-32129, JP-B-48-39165 and U.S. Patent 3,443,934.

Examples of the compound which releases a photographically useful group from an oxidation product by another mechanism include hydroquinone derivatives represented by the following formulas (Y-5) and (Y-6):

wherein β' has the same meaning as defined in the formula (Y-4); G and Z2 have the meaning as defined in the formula (Y-1), respectively; 27 has the same meaning as Z2; Z8 represents a hydrogen atom or the same substituent as defined with respect to Z1; and Z7 and Z8 may be the same or different. Specific examples of these are described in U.S. Patent No. 3,725,062.

These hydroquinone derivative releasers may contain a nucleophilic group in their molecules. Specific examples thereof are described in JP-A-4-97347.

Still further examples of Y include p-hydroxydiphenylamine derivatives as described in U.S. Patent 3,443,939 and hydrazine derivatives as described in U.S. Patents 3,844,785 and 4,684,604 and in Research Disclosure (R.D.), No. 128, page 22.

Other examples of the negative-working release agent include a compound represented by the following formula (Y-7):

Coup-G (Y-7)

where Coup means a group capable of coupling with an oxidation product of a p-phenylenediamine or p-aminophenol, ie a group which acts as a photographic couplers. Specific examples are described in British Patent Specification 1,330,524.

(2) Further examples of Y include a positive working release agent which releases a photographically usable group in counter-correspondence to development.

Examples of the positive-working releaser include a releaser which exhibits its function by reduction during processing. Preferred examples thereof include the following formula (Y-8):

wherein EAG represents a group which receives an electron from a reducing substance; N represents a nitrogen atom; W represents an oxygen atom, a sulfur atom or -NZ¹¹- and after EAG has received an electron, the N-W bond is cleaved; Z¹¹ represents an alkyl or aryl group; and Z⁹ and Z¹⁰ each represents a single bond or a monovalent or divalent substituent other than a hydrogen atom, with the proviso that the solid line represents a bond and the dashed lines indicate that at least one of these dashed lines is connected to each other.

A preferred example of the group represented by the formula (Y-8) includes the following formula (Y-9):

wherein O represents an oxygen atom (in other words, W in (Y-8) represents an oxygen atom); Z¹² represents an atomic group capable of forming a heterocyclic ring containing an N-O bond and cleavage of the Z¹²-G bond after cleavage of the N-O bond, and Z¹² may have one or more substituents and may be condensed with a saturated or unsaturated ring; and Z¹³ represents -CO- or -SO₂-.

A preferred example of the group represented by the formula (Y-9) includes the following formula (Y-10):

wherein Z¹⁴ represents an alkyl group, an aryl group or an aralkyl group; Z¹⁵ represents a carbamoyl group or a sulfamoyl group; Z¹⁵ represents an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an alkylthio group, an aryloxy group, an arylthio group, a halogen atom, a cyano group or a nitro group; and b is an integer of 0 to 3. In the formula (Y-10), the nitro group is also substituted at the ortho or para position of the nitrogen atom.

More preferably, Z¹⁵ is a C₁₂₋₃₀ carbamoyl group or sulfamoyl group substituted with an alkyl group.

Specific examples thereof are described in JP A-62-215270 and US Patent 4,783,396.

Other examples of the positive-acting releaser showing its function include BEND compounds as described in U.S. Patent Nos. 4,139,379 and 4,139,389, Carquin compounds as described in British Patent No. 11,445, and releasers as described in JP-A-54-126535 and JP-A-57-84453.

The reducible releaser represented by Y, such as (Y-8), is used in combination with a reducing agent. Alternatively, an LDA compound containing a reducing group in its molecule may be used. The LDA compound is further described in U.S. Patent 4,551,423.

Furthermore, the positive-working releaser includes releasers that are contained in a photosensitive material as a reducing product and are inactivated by oxidation during processing.

Examples thereof include Fields compounds as described in JP-A-51-63618 and US Patent 3,980,479 and Hinshaw compounds as described in JP-A-49-111628, JP-A-52-4819 and US Patent 4,199,354.

Another example of Y includes the following formula (Y-11):

wherein Z¹⁷ and Z¹⁹ independently represent a hydrogen atom, an acyl, alkoxycarbonyl or aryloxycarbonyl group which may be substituted; Z¹⁸ represents an alkyl, aryl, aralkyl, acyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, sulfonyl or sulfamoyl group which may be substituted; and Z²⁰ and Z²¹ each independently represent a hydrogen atom or an alkyl, aryl or aralkyl group which may be substituted. Specific examples thereof are described in JP-A-62-245270 and JP-A-63-46450.

Yet another mechanism of a positive-acting releaser is provided by a thiazolidine-type releaser. The thiazolidine-type releaser is described, for example, in US Patent 4,468,451.

Whatever compound Y is used as a release agent, Y preferably has at least one ballast group of 10 or more carbon atoms.

In the present invention, the compound represented by formula (1) can exert its effect more remarkably when it comprises a negative-working releaser.

The dye group represented by formula (2) is further described below.

In the formula (2), R³ represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, or a substituted or unsubstituted alkyl, aralkyl, cycloalkyl, aryl, heterocyclic, alkoxy, aryloxy, amino, acylamino, sulfonylamino, acyl, sulfonyl, carbamoyl, sulfamoyl, ureido, alkylthio or arylthio group. R¹ and R² each independently represent a hydrogen atom or a substituent as defined by R³. n represents an integer of 0 to 5. When n is 2 to 5, the plural R³ groups may be the same or different.

Dye and X are bonded to each other to any of the groups R¹, R² and R³.

Preferred examples of R1 include a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms (e.g., methyl, isopropyl, t-butyl, methoxyethyl, β-cyanoethyl, trifluoromethyl), a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms (e.g., methoxy, ethoxy, methoxyethoxy), a substituted or unsubstituted aryl group having 6 to 8 carbon atoms (e.g., phenyl, p-methoxyphenyl, p-hydroxyphenyl), a hydroxyl group, a cyano group, a carbamoyl group, and a carboxyl group.

Preferred examples of R² include a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms (e.g. methyl, butyl, methoxyethyl, β-cyanoethyl, β-acetylaminoethyl, β-methanesulfonylaminoethyl), a substituted or unsubstituted aryl group having 6 to 8 carbon atoms (e.g. phenyl, p-methoxyphenyl, p-chlorophenyl), a substituted or unsubstituted alkyl group having 7 to 12 carbon atoms (e.g. B. Benzyl, β-phenetyl, p-methoxyphenetyl), a substituted or unsubstituted alkoxy group with 1 to 6 carbon atoms (e.g. methoxy, ethoxy, methoxyethoxy), an acylamino group with 2 to 8 carbon atoms (e.g. acetylamino, butyloylamino, pivaloylamino) and a sulfonylamino group with 1 to 7 carbon atoms (e.g. methanesulfonylamino, benzenesulfonylamino).

Preferred examples of R³ include a hydrogen atom, a halogen atom, a cyano group, a carboxyl group, a substituted or unsubstituted carbamoyl group having 1 to 5 carbon atoms (e.g., carbamoyl, N-methylcarbanoyl, N,N- dimethylcarbamoyl), a substituted or unsubstituted sulfamoyl group having 0 to 4 carbon atoms (e.g., sulfamoyl, N-methylsulfamoyl, N,N-dimethylsulfamoyl), a substituted or unsubstituted sulfonyl group having 1 to 4 carbon atoms (e.g., methanesulfonyl, ethanesulfonyl), a methyl group, a methoxy group, and a methoxyethoxy group.

Dye and X are bonded to each other to any of the groups R¹, R² or R³, preferably R² and R³.

Specific examples of the compound of the present invention are shown below.

The synthesis of these compounds is described, for example, in JP-A-6-301179.

In the present invention, the compound represented by formula (1) is preferably incorporated in the same layer as the silver halide. In the present invention, the above compound can be used in a wide range of amounts, i.e., from 0.01 to 5 mol, preferably from 0.05 to 1 mol, per mol of silver.

The compound used in the present invention is a yellow dye-providing compound. The compound used in the present invention is used in combination with a magenta dye-providing compound and a cyan dye-providing compound to obtain a full-color image. Alternatively, the compound used in the present invention may be used in combination with another yellow dye-providing compound. The dye-providing compound used in combination with the compound used in the present invention is represented by the following formula (4):

wherein Dye' represents a dye (particularly magenta or cyan) or a dye precursor; Y' represents a group which makes a difference in the diffusibility of the dye component in accordance with or in counter-accordance with a reduction reaction of photosensitive silver halide having an imagewise latent image to silver between before and after the reaction reduction (i.e., the same meaning as Y); X' represents a single bond or a bonding group (i.e., the same meaning as X); i is an integer of 1 or more; and j is 1 or 2, provided that when i is 2 or more, or when j is 2, the plural (Dye') groups or ((Dye')i - X) groups may be the same or different.

The heat-developable photosensitive material according to the present invention essentially comprises photosensitive silver halide, a binder and optionally an organic metal salt as an oxidizing agent, a dye-providing compound (the reducing agent may also serve as a dye-providing compound, as mentioned later) on a support.

These components are often incorporated in the same layer, but can also be incorporated separately in different layers if they are reactive with each other. For example, if a colored dye-providing compound is present in layers below the silver halide layers, it can inhibit the decrease in sensitivity. The reducing agent is preferably incorporated in the heat-developable, photosensitive material, but can be introduced from the outside, e.g. by diffusing the reducing agent from the dye-fixing material, as mentioned later.

In order to obtain a wide range of colors in the chromaticity diagram from the subtractive primary colors, i.e., yellow, magenta and cyan, at least three silver halide emulsion layers having photosensitivities in different spectral regions are used in combination. For example, a combination of a red-sensitive layer, an infrared-sensitive layer (I) and an infrared-sensitive layer (II) may be used as described in JP-A-59-180550, JP-A-64-13546, JP-A-62-253159 and EP-A-479167. These photosensitive layers may be arranged in various orders known in the field of ordinary color photosensitive materials. These photosensitive layers may be divided into two or more layers each, if necessary, as described in JP-A-1-252954.

The heat-developable light-sensitive material may be provided with various non-light-sensitive layers such as a protective layer, an underlayer, an intermediate layer, a yellow filter layer and an antihalation layer between the above silver halide emulsion layers and various auxiliary layers such as a back layer on the opposite side of the support. Specifically, a layer structure as described in the above-mentioned patents, an underlayer as described in U.S. Patent 5,051,335, an intermediate layer containing a solid pigment as described in JP-A-1-167838 and JP-A-61-20943, an intermediate layer containing a reducing agent or a DIR compound as described in JP-A-1-120553, JP-A-5-34884 and JP-A-2-64634, an intermediate layer containing an electron transfer agent as described in U.S. Patents 5,017,454 and 5,139,919 and in JP-A-2-235044 and a protective layer containing a reducing agent as described in JP-A-4-249245 may be provided singly or in combination.

If the support is a polyethylene laminated paper containing a white pigment such as titanium oxide, the back layer is preferably designed to have an antistatic effect and to have a surface resistance of 10¹² Ω cm or less.

The silver halide for use in the present invention may be any of the group consisting of silver chloride, silver bromide, silver bromoiodide, silver bromochloride, silver chloroiodide and silver bromochloroiodide.

The silver halide emulsion for use in the present invention may be a surface latent image type emulsion or an internal latent image type emulsion. The internal latent image type emulsion may be used as a direct reversal emulsion in combination with a nucleating agent or light fogging agent. The silver halide emulsion to be used in the present invention may be a so-called core-shell emulsion having different phase from core to shell or may have different silver halide compositions bonded to each other via an epitaxial bond. The silver halide emulsion may be monodisperse or polydisperse. Monodisperse silver halide emulsions may be used in admixture to control gradation as described in JP-A-1-167743 and JP-A-4-223463. The grain size of the silver halide grains is preferably 0.1 to 2 µm, more preferably 0.2 to 1.5 µm. The crystal load of the silver halide grains may be any of the group of regular crystal such as cube, octahedron and tetradecahedron, irregular crystal such as sphere and table having a high aspect ratio, crystal having a crystal defect such as twin plane, composite thereof and other crystal forms.

Specifically, any of the silver halide emulsions prepared by the process described in U.S. Patents 4,500,626 (column 50) and 4,628,021, Research Disclosure (hereinafter referred to as RD) No. 17029 (1978), 17643 (December 1978), pages 22 to 23, 18716 (November 1979), pages 648 and 307105 (November 1989), pages 863 to 865, JP-A-62-253159, JP-A-64-13546, JP-A- 2-236546 and JP-A-3-110555, P. Glafkides, Chimie et Physigue Photoaraphiaue, Paul Montel (1967), GF Duffin, Photoaraphic Emulsion Chemistrv, Focal Press (1966) and VL Zelikman et al., Makina and Coatina Photoqraphic Emulsion, Focal Press (1964).

In the process for preparing the light-sensitive silver halide emulsion, desalting, i.e., removal of excess salts, is preferably carried out. For the desalting, noodle washing, which involves gelation of gelatin, may be carried out. Alternatively, a sedimentation process using an inorganic salt (e.g., sodium sulfate), an anionic surfactant or an anionic polymer (e.g., sodium polystyrenesulfonate) containing polyvalent anions, or a gelatin derivative (e.g., aliphatic acylated gelatin, aromatic acylated gelatin, aromatic carbamoylated gelatin) may be used. Among them, the sedimentation process is preferred.

The light-sensitive silver halide emulsion for use in the present invention may contain heavy metals such as iridium, rhodium, platinum, cadmium, zinc, thallium, lead, iron and osmium for various purposes. These compounds may be used singly or in combination. Their amount depends on the purpose, but is normally about 10-9 to 10-3 mol per mol of silver halide. Such a compound may be uniformly incorporated into grains or located inside or on the surface of grains. Specifically, an emulsion as described in JP-A-2-236542, JP-A-1-116637 and JP-A-5-181246 is preferably used.

In the step of forming the light-sensitive silver halide emulsion grains used in the present invention, as a silver halide solvent, a thiocyanate, ammonia, a 4-substituted thioether compound, an organic thioether derivative as described in JP-B-47-11386, or a sulfur-containing compound as described in JP-A-53-144319 can be used.

For other conditions, reference may be made to the literature cited above, for example to P. Glafkides, Chimie et Physique Photographique, Paul Montel (1967), GF Duffin, Photographic Emulsion Chemistry, Focal Press (1966) and VL Zelikman et al., Making and Coating Photographic Emulsion, Focal Press (1964). Specifically, the emulsion can be prepared by the acid method, the neutral method and the ammonia method. The reaction between a soluble silver salt and a soluble halogen salt can be carried out by a single jet method, a double jet method and a combination thereof. The double jet method is preferably used to obtain a monodisperse emulsion.

A method in which grains are formed in the presence of excess silver ions (reverse mixing method) may be used. Furthermore, a so-called controlled double jet method in which a pAg value of a liquid phase in which silver halide grains are formed is kept constant may also be used.

The concentration, amount or rate of addition of silver salts and halides may be increased to accelerate the growth of grains (as described in JP-A-55-142329, JP-A-55-158124 and U.S. Patent 3,650,757).

Stirring of the reaction solution can be carried out by any known stirring method. The temperature and pH of the reaction solution during the formation of silver halide grains can be freely predetermined according to the purpose. The pH is preferably 2.2 to 7.0, more preferably 2.5 to 6.0.

In general, the photosensitive silver halide emulsion is a chemically sensitized silver halide emulsion. When the emulsion is used for ordinary photosensitive materials, the chemical sensitization of the photosensitive silver halide emulsion according to the present invention can be carried out by the chalcogen sensitization method such as the sulfur sensitization method, the selenium sensitization method and the tellurium sensitization method, the noble metal sensitization method using gold, platinum or palladium and the reduction sensitization method, singly or in combination (as described in JP-A-3-110555 and JP-A-5-241267). The chemical sensitization can be carried out in the presence of a nitrogen-containing heterocyclic compound. (as described in JP-A-62-253159). An antifogging agent as described later may be added after completion of chemical sensitization. Specifically, a method as described in JP-A-5-45833 and JP-A-62-40446 may be used.

The pH value during chemical sensitization is preferably 5.3 to 10.5, more preferably 5.5 to 8.5. The pAg value during chemical sensitization is preferably 6.0 to 10.5, more preferably 6.8 to 9.0.

The coating amount of the light-sensitive silver halide emulsion used in the present invention is 1 mg/m² to 10 g/m² in terms of silver.

The light-sensitive silver halide emulsion used in the present invention is spectrally sensitized with a methine dye or the like to obtain a color sensitivity to green, red or infrared. If necessary, the blue-sensitive emulsion may be spectrally sensitized in a blue region.

Examples of dyes for use in spectral sensitization include cyanine dye, merocyanine dye, compound cyanine dye, compound merocyanine dye, holopolar cyanine dye, hemicyanine dye, styryl dye and hemioxonol dye.

Specifically, sensitizing dyes can be used as described in U.S. Patent 4,617,257 and JP-A-59-180550, JP-A-64-13546, JP-A-5-45828 and JP-A-5-45834.

These sensitizing dyes can be used individually or in combination. A combination of these sensitizing dyes is often used especially for wavelength tuning in supersensitization or spectral sensitization.

In addition to these sensitizing dyes, a dye which does not itself have a spectral sensitizing effect or a compound which essentially does not absorb visible light but has a supersensitizing effect can incorporated into the emulsion (as described in US Patent 3,615,641 and JP-A-63-23145).

The time at which these sensitizing dyes are introduced into the emulsion may be during or before or after chemical ripening, or may be before or after nucleation of silver halide grains as described in U.S. Patents 4,183,756 and 4,225,666. These sensitizing dyes or supersensitizers may be added in the form of a solution in an organic solvent such as methanol, a dispersion in gelatin, or a solution in a surfactant. The amount of these sensitizing dyes to be added is normally 108 mol to 102 mol per mol of silver halide.

Additives which can be used in these processes and known photosensitive additives which can be incorporated into the heat-developable photosensitive material are also described in the above-cited RD Nos. 17643, 18716 and 307105 as shown in a table below.

The binder in the light-sensitive material or the dye-fixing material is preferably hydrophilic. Examples thereof include those described in the above-mentioned RD documents and in JP A-64-13546, pages 71 to 75. Specifically, a transparent or semi-transparent hydrophilic binder is preferred. Examples thereof include proteins such as gelatin and gelatin derivatives, natural compounds such as cellulose derivatives, starch, gum arabic, dextran, pullulan and other polysaccharides, and synthetic high molecular compounds such as polyvinyl alcohol, polyvinylpyrrolidone and acrylamide. Further, a polymer having high water absorption, as described in U.S. Patent No. 4,960,681 and JP-A-62-245260, that is, a homopolymer of a vinyl monomer having -COOM or -SO₃M (wherein M is a hydrogen atom or alkali metal atom) or a copolymer of such vinyl monomers with other vinyl monomers (e.g., sodium methacrylate, ammonium methacrylate, Sumikagel available from Sumitomo Chemical Co., Ltd.). Two or more of these binders may be used in combination. In particular, a combination of gelatin and the binders is preferred. Gelatin may be selected from the group consisting of lime-treated gelatin, acid-treated gelatin and decalcified gelatin having a reduced calcium content or the like depending on various purposes. These gelatin products may preferably be used in combination.

In the system where heat development is carried out by supplying a small amount of water, water absorption can be carried out quickly if the polymer having high water absorption is used. Furthermore, if a polymer having high water absorption is incorporated into the dye-fixing layer or its protective layer, the dyes can be prevented from being retransferred from the dye-fixing element to other elements after transfer.

In the present invention, the amount of the binder is preferably 20 g/m2 or less, more preferably 10 g/m2 or less, and particularly preferably 0.5 g/m2 to 7 g/m2.

In the present invention, the photosensitive member may contain an organic metal salt as an oxidizing agent in combination with the photosensitive silver halide emulsion. Among them, organic silver salts are particularly preferred as organic metal salts.

Examples of organic compounds that can be used as an oxidizing agent to form such an organic silver salt include benzotriazoles, aliphatic acids, and other compounds as described in U.S. Patent 4,500,626 (columns 52 to 53). Other useful examples of organic compounds include silver acetylene as described in U.S. Patent 4,775,613.

Two or more of these organic silver salts can be used in combination.

The above-mentioned organic silver salt may be used in an amount of 0.01 to 10 mol, preferably 0.01 to 1 mol, per mol of the photosensitive silver halide. The sum of the coating amount of the photosensitive silver halide and the organic silver salt is preferably 0.05 mg/m² to 10 g/m², more preferably 0.1 g/m² to 4 g/m², in terms of silver.

The reducing agent for use in the present invention includes those known in the field of light-sensitive material. Reducing dye-providing compounds as described later may also be used (in this case, other reducing agents may be used in combination therewith). Furthermore, a reducing precursor which has no reducing action itself but exerts a reducing action by a nucleophilic reagent or by heat during development may be used.

Examples of reducing agents for use in the present invention include reducing agents and reduction precursors as described in U.S. Patents 4,500,626 (columns 49 to 50), 4,839,272, 4,330,617, 4,590,152, 5,017,454 and 5,139,919, JP- A-60-140335 (pages 17 to 18), JP-A-57-40245, JIP-A-56-138736, JP-A-59-178458, JP- A-59-53831, JP-A-59-182449, JP-A-59-182450, JP-A-60-119555, JP-A-60-128436, JP- A-60-128439, JP-A-60-198540, JP-A-60-181742, JP-A-61-259253, JP-A-62-244044, JP- A-62-131253, JP-A-62-131256, JP-A-64-13546 (pages 40 to 57), JP-A-1-120553 and in EP A-220746 (pages 78 to 96).

A combination of different reducing agents as described in US Patent 3,039,869 may be used.

When a non-diffusible reducing agent is used, an electron transfer agent and/or an electron transfer agent precursor may optionally be used in combination therewith to accelerate the migration of electrons between the non-diffusible reducing agent and the developable silver halide. In particular, those compounds are preferably used which are present in US Patent 5,139,919 and EP-A-418743. Furthermore, a method for stably introducing the reducing agent into the layers as described in JP-A-2-230143 and JP-A-2-235044 may preferably be used.

The electron transfer agent or its precursor can be selected from the above-mentioned reducing agents or their precursors. The electron transfer agent or its precursor preferably has a greater mobility than the non-diffusible reducing agent (electron donor). Preferred electron transfer agents are 1-phenyl-3-pyrazolidones or aminophenols.

The non-diffusible reducing agent (electron donor) to be used in combination with the electron transfer agent can be selected from compounds which do not substantially migrate into the layers constituting the photosensitive material into the above-mentioned reducing agents. Preferred examples thereof include hydroquinones, sulfonamidophenols, sulfonamidonaphthols, compounds described as electron donors in JP-A-53-110827 and U.S. Patents 5,032,487, 5,026,634 and 4,839,272, and non-diffusible dye-providing reducing compounds as described later.

Further, a precursor of an electron donor as described in JP-A-3-160443 can be preferably used.

Furthermore, the intermediate layer and the protective layer may contain reducing agents incorporated therein for various purposes such as preventing color stains and improving color reproducibility. Specifically, reducing agents as described in EP-A-524649, E. P-A-357040, JP-A-4-249245, JP-A-2-46450 and JP-A-63-186240 are preferably used. Further, development inhibitor-releasing reducing compounds as described in JP-B-3-63733, JP-A-1-150135, JP-A-2-64634, JP-A-3-43735 and EP-A-451 833 can be used.

In the present invention, the total amount of reducing agents to be incorporated is preferably 0.01 to 20 mol, more preferably 0.1 to 10 mol, per mol of silver.

In the present invention, silver can be used as an image-forming substance. Alternatively, the image-forming substance comprises a compound which produces or releases a mobile dye in accordance or in counter-accordance with the reduction reaction of silver ion to silver at high temperature, i.e., a dye-providing compound.

Examples of the dye-providing compounds for use in the present invention include compounds (couplers) which form a dye by an oxidative coupling reaction. These couplers may be 2-equivalent or 4-equivalent. Further, 2-equivalent couplers containing a non-diffusible group as a leaving group which forms a diffusible dye by an oxidative coupling reaction may be preferably used. These non-diffusible groups may form a polymer chain. Specific examples of color developing agents and couplers are further described in T. H. James, The Theory of the Photographic Process, 4th edition (pages 291 to 334 and pages 354 to 361) RD No. 307105 (page 871), JP A-58-123533, JP-A-58-149046, JP A-58-149047, JP-A-59- 111148, JP-A-59-124399, JP-A-59-174835, JP-A-59-231539, JP-A-59-231540, JP-A-60- 2950, JP-A-60-2951, JP-A-60-14242, JP-A-60-23474 and JP-A-60-66249.

Another example of a dye-providing compound is a compound that serves to imagewise release or diffuse a diffusing dye. This type of compound can be represented by the following formula [LI]:

wherein DYE represents a dye group or dye precursor group which has been temporarily shifted to a short wavelength; Y represents a single bond or a bonding group; Z represents a group which has a different diffusibility of the

reproduced connection or

to achieve different diffusibility of

in correspondence or anti-correspondence to a photosensitive silver salt having an imagewise latent image; s is an integer from 1 to 5; and t is 1 or 2, with the proviso that when either s or t is not 1, the plurality of DYE groups may be the same or different.

Specific examples of the dye-providing compound represented by the formula [LI] include the following compounds (1) to (5). The compounds (1) to (3) form a diffusing dye image (positive dye image) in accordance with the development of silver halide. The compounds (4) and (5) form a diffusing dye image (negative dye image) in accordance with the development of silver halide.

(1) Dye developing agents in which a hydroquinone developing agent and a dye component are combined, as described in U.S. Patents 3,134,764, 3,362,819, 3,597,200, 3,544,545 and 3,482,972 and JP-B-3-68387, can be used. These dye developing agents are diffusible under alkaline conditions, but react with silver halide and become non-diffusible.

(2) As described in U.S. Patent No. 4,503,137, non-diffusible compounds can be used which release a diffusible dye under alkaline conditions but react with silver halide to lose this ability. Examples of the non-diffusible compounds include compounds which release a diffusible dye by an intramolecular nucleophilic substitution reaction as described in U.S. Patent No. 3,980,479 and compounds which release a diffusible dye by an intramolecular rearrangement reaction of isooxazolone rings as described in U.S. Patent No. 4,199,354.

(3) As described in U.S. Patents 4,559,290 and 4,783,396, EP-A-220746, JIII Journal of Technical Disclosure 87-6199 and JP-A-64-13546, non-diffusible compounds can be used which react with a reducing agent which remains unoxidized after development to release a diffusible dye.

Examples of non-diffusible compounds include compounds which release a diffusible dye by an intramolecular nucleophilic substitution reaction after reduction, as described in U.S. Patents 4,139,389 and 4,139,379 and in JP-A-59-185333 and JP-A-57-84453, compounds which release a diffusible dye by an intramolecular electron migration reaction after reduction, as described in U.S. Patent 4,232,107, in JP-A-59-101649 and JP-A-61-88257 and in RD No. 24025 (1984), compounds which release a diffusible dye by cleavage of a single bond after reduction, as described in West German Patent Publication 3,008,588A, in JP-A-56-142530 and in U.S. Patents 4,343,893 and 4,619,884, nitro compounds which release a diffusible dye after acceptance of electrons, as described in U.S. Patent 4,450,223, and compounds that release a diffusible dye upon acceptance of electrons, as described in U.S. Patent 4,690,610.

Preferred examples of the non-diffusible compounds include compounds containing an N-X bond (in which X represents an oxygen, sulfur or nitrogen atom) and an electrophilic group per molecule as described in EP-A-220746, JIII Journal of Technical Disclosure 87-6199, U.S. Patent 4,783,396 and JP-A-63-201653, JP-A-63-201654 and JP-A-64-13546, compounds containing an SO₂-X bond (in which X represents the same meaning as X or represents -SO₂-) and an electrophilic group per molecule as described in JP-A-1-26842, and compounds containing a C-X' bond (in which X' represents the same meaning as X or represents -SO₂-) and one electrophilic group per molecule as described in JP-A-63- 271341. Compounds which form a diffusible dye by cleavage of a single bond after reduction by a π-bond conjugated with an electron-accepting group as described in JP-A-1-161237 and JP-A-1-161342 can also be used.

Among these, compounds containing one N-X bond and one electrophilic group per molecule are particularly preferred. Specific examples thereof include compounds (1) to (3), (7) to (10), (12), (13), (15), (23) to (26), (31), (32), (35), (36), (40), (41), (44), (53) to (59) and (70) as described in EP-A-220746 or U.S. Patent 4,783,396, compounds (11) to (23) as described in JIII Journal of Technical Disclosure 87-6199, and compounds (1) to (84) as described in JP A-13546.

(4) Coupler compounds containing a diffusible dye as a splittable group which release a diffusible dye by reaction with an oxidation product of a reducing agent (DDR couplers) can be used. Specific examples are described in British Patent 1,330,524, JP-B-48-39165 and U.S. Patents 3,443,940, 4,474,867 and 4,483,914.

(5) Compounds capable of reducing silver halides or organic silver salts and releasing a diffusible dye by reducing the silver halides or organic silver salts (DRR compounds) can be used. These compounds do not require other reducing agents. Consequently, the compound is preferred because it does not cause stains on the image with an oxidative decomposition product of reducing agents. Typical examples thereof are described in US Patent Nos. 3,928,312, 4,053,312, 4,055,428, 4,336,322, 3,725,062, 3,728,113, 3,443,939 and 4,500,626, JP-A-56-65839, JP-A-59-69839, JP-A-53-3819, JP-A-51-104343, JP-A-58-116537 and JP-A-57-179840 and RD No. 17465. Specific examples thereof include compounds described in US Patent No. 4,500,626 (columns 22 to 44). Among these, particularly preferred are the compounds (1) to (3), (10) to (13), (16) to (19), (28) to (30), (33) to (35), (38) to (40) and (42) to (64) described in US Patent 4,500,626. Furthermore, compounds described in US Patent 4,639,408 (columns 37 to 39) can be used.

Examples of dye-providing compounds other than the above-mentioned couplers and dye-providing compounds represented by formula [LI] include dye-silver compounds in which an organic silver salt and a dye are combined (RD, May 1978, pages 54 to 58), azo dyes for use in a silver dye heat development bleaching process (US Patent 4,235,957, RD, April 1976, pages 30 to 32) and leuco dyes (US Patent 3,985,565 and 4,022,617).

Hydrophobic additives such as dye-providing compounds and non-diffusible reducing agents can be incorporated into the layers constituting the photosensitive material according to any known method. In this case, a high boiling organic solvent as described in U.S. Patents 4,555,470, 4,536,466, 4,536,467, 4,587,206, 4,555,476 and 4,599,296 and described in JP-B-3-62256 may be used in combination with an organic solvent having a boiling point as low as 50ºC to 160ºC, if necessary. Two or more of these dye-providing compounds, non-diffusible reducing agents and high-boiling organic solvents may be used in combination.

The amount of the high boiling organic solvent is 10 g or less, preferably 5 g or less, and more preferably 0.1 g to 1 g, per g of the dye-providing compound used, and 1 ml or less, preferably 0.5 ml or less, more preferably 0.3 ml or less, per g of the binder used.

Alternatively, a dispersion method using a polymer as described in JP-B-51-39853 and JP-A-51-59943 may be used.

A substantially water-insoluble compound may be finely dispersed in the binder rather than using the methods described above.

When a hydrophobic compound is dispersed in a hydrophilic colloid, various colloids can be used. For example, compounds mentioned as surfactants in JP-A-59-157636 (pages 37 to 38) and the RD references cited above can be used.

In the heat-developable photosensitive material according to the present invention, a compound which activates development and stabilizes an image may be incorporated into the photosensitive material. Preferred examples thereof are described in U.S. Patent No. 4,500,626 (columns 51 to 52).

In the system in which an image is formed by the diffusion transfer of a dye, various compounds may be incorporated into the layers constituting the heat-developable photosensitive material for fixing or decolorizing undesirable dyes or colored products in order to improve the white background properties of the resulting image.

For example, compounds described in EP-A-353741, EP A-461416, JP-A-63-163345 and JP-A-62-203158 can be used.

The layers constituting the heat-developable photosensitive material according to the present invention may contain various pigments or dyes incorporated therein to improve color separability or to increase sensitivity.

For example, compounds described in the above-cited RD references and compounds and layer structures as described in EP-A-479167, EP-A-502508, JP-A-1-167838, JP-A-4-343355, JP-A-168252 and JP-A-61-20943 can be used.

In the system where an image is formed by diffusing and transferring a dye, a dye-fixing element is used in combination with the heat-developable photosensitive material. The dye-fixing element may be separately coated on a support different from the support for the photosensitive material, or it may be coated on the same support as the photosensitive material. For the relationship between the photosensitive material and the dye-fixing element, between the photosensitive material and the support, and between the photosensitive material and the white reflective layer, those described in U.S. Patent 4,500,626 (column 57) can be applied to the present invention.

The dye-fixing element which can be preferably used in the present invention comprises at least one layer containing a mordant and a binder. As the mordant, a mordant known in the art can be used. Specific examples of such a mordant include mordants described in U.S. Patent 4,500,626 (columns 58 to 59), JP-A-61-88255 (pages 32 to 41) and JP-A-1-161236 (pages 4 to 7), and mordants described in JP-A-62-244043 and JP-A-62-244036. Further, dye-accepting high molecular compounds as described in U.S. Patent 4,463,079 can be used.

As the binder to be incorporated in the dye-fixing element according to the present invention, the above-mentioned hydrophilic binder can be preferably used. Furthermore, carrageenans as described in EP-A-443529 can also be preferably used.

The dye-fixing element may contain auxiliary layers such as a protective layer, a release layer and an anti-curl layer, if necessary. In particular, a protective layer is advantageously provided.

The layers constituting the heat-developable photographic light-sensitive material and the dye-fixing element may contain a plasticizer, a lubricant or a high-boiling organic solvent as an agent for improving the releasability of the light-sensitive material from the dye-fixing element. Specific examples thereof include those described in the above-cited RD references and JP-A-62-245253.

Furthermore, various silicone oils (ranging from dimethyl silicone oil to modified silicone oils obtained by introducing various organic groups into dimethylsiloxane) can be used for the above purposes. Usable examples of such silicone oils are various modified silicone oils described in Modified Silicone Oil (technical report published by Shin-Etsu Silicone Co., Ltd.), pages 6 to 18B, particularly carboxy modified silicone (trade name: X-22-3710).

Furthermore, silicone oils described in JP-A-62-215953 and JP-A-63-46449 can also be effectively used.

The heat-developable photosensitive material or dye-fixing element may contain a discoloration inhibitor. Examples of these include oxidation inhibitors, ultraviolet absorbing agents and some types of metal complexes.

Examples of the antioxidant include chroman compounds, coumaran compounds, phenol compounds (e.g., hindered phenols), a hydroquinone derivative, a hindered amine derivative, and spiroindane compounds. Compounds as described in JP-A-61-159644 can also be effectively used as antioxidants.

Examples of the ultraviolet absorbing agents include benzotriazole compounds (US Patent 3,533,794), 4-thiazolidone compounds (US Patent 3,352,681), benzophenone compounds (JP-A-46-2784) and compounds (JP-A-54-48535, JP-A-62-136641, JP-A-61-88256). Furthermore, ultraviolet absorbing polymers as described in JP-A-62-260152 can also be effectively used as the ultraviolet absorbing agents.

Examples of the metal complexes include compounds described in U.S. Patents 4,241,155, 4,245,018 (columns 3 to 36) and 4,254,195 (columns 3 to 8) and JP-A-62-174741, JP-A-61-88256 (pages 27 to 29), JP-A-63-199248, JP-A-1-75568 and JP-A-1-74272.

The discoloration inhibitor for inhibiting the transfer of a dye that has been transferred to the dye-fixing material can be incorporated into the dye-fixing element beforehand or can be introduced into the dye-fixing element from the outside, e.g. from the light-sensitive material.

The above-mentioned antioxidants, ultraviolet absorbing agents and metal complexes may be used in combination.

The heat-developable photosensitive material or the dye-fixing element may contain a fluorescent brightening agent. The fluorescent brightening agent is particularly preferably incorporated into the dye-fixing element or supplied from the outside of the dye-fixing element, e.g., from the photosensitive material. Examples of the fluorescent brightening agent include compounds as described in K. Veenkataraman, Chemistry of Synthetic Dyes, Volume V, Chapter 8 and JP-A-61-143752. Specific examples of the fluorescent brightening agent include stilbene compounds, comarin compounds, biphenyl compounds, benzoxazolyl compounds, naphthalimide compounds, pyrazoline compounds and carbostyryl compounds.

The fluorescent whitening agent can be used in combination with a discoloration inhibitor or an ultraviolet absorbing agent:

Specific examples of these discoloration inhibitors, ultraviolet absorbing agents and fluorescent brightening agents are described in JP-A-62-215272 (pages 125 to 137) and in JP-A-1-161236 (pages 17 to 43).

Examples of film hardeners to be incorporated into the layers constituting the heat-developable photosensitive material or the dye-fixing element include those described in the above-mentioned RD references, U.S. Patent Nos. 4,678,739 (column 41) and 4,791,042, JP-A-59-116655, JP-A-62-245261, JP-A-61-18942 and JP-A-4-218044. Specific examples of the film hardeners include aldehyde film hardeners (e.g. formaldehyde), aziridine film hardeners, epoxy film hardeners, vinylsulfone film hardeners (e.g. N,N'-ethylenebis(vinylsulfonylacetamido)ethane), N-methylol film hardeners (e.g. dimethylol urea) and high molecular weight film hardeners (e.g. compounds as described in JP-A-62-234157).

The film hardener may be used in an amount of 0.001 g to 1 g, preferably 0.005 g to 0.5 g per gram of gelatin applied. Such a film hardener may be incorporated into each of the layers constituting the light-sensitive material or the dye-fixing element, or it may be incorporated separately into two or more layers.

The layers constituting the heat-developable photosensitive material or the dye-fixing element may contain various antifogging agents or photographic stabilizers or precursors thereof. Specific examples of these compounds are described in the above-cited RD references, U.S. Patents 5,089,378, 4,500,627, 4,614,702, 4,775,610, 4,628,500 and 4,983,494, JP-A-64-13546 (pages 7 to 9, pages 57 to 71, pages 81 to 97), JP-A-62-174747, JP-A-62-239148, JP-A-1-150135, JP-A-2-110557 and JP-A-2-178650 and RD No. 17,643 (1978, pages 24 to 25).

These compounds are preferably used in an amount of 5 x 10⁻⁶ to 1 x 10⁻¹ mol, more preferably 1 x 10⁻⁵ to 1 x 10⁻² mol, per mol of silver.

The layers constituting the heat-developable photosensitive material or the dye-fixing element may contain various surface active agents for coating assistance, improving releasability and slip properties, inhibiting electric charge, accelerating development, or for the like. Specific examples of surface active agents are described in the above-cited RD references and in JP-A-62-173463 and JP-A-62-183457.

The layers constituting the heat-developable photosensitive material or the dye-fixing element may contain an organic fluorine compound incorporated therein for improving slip properties and releasability, inhibiting electric charge or for the like. Representative examples of the organic fluorine compound include fluorine-containing surfactants as described in JP-B-57-9053 (columns 8 to 17), JP-A-61-20944 and JP-A-62-135826, and hydrophobic fluorine compounds comprising a fluorine-containing oil compound (e.g., fluorine oil) and a solid fluorine resin compound (e.g., tetrafluoroethylene resin).

The heat-developable photosensitive material or the dye-fixing element may contain a matting agent. Examples of the matting agent include silica, polyolefin and polymethacrylate as described in JP-A-61-88256 (page 29), and benzoguanamine resin beads, polycarbonate resin beads and AS resin beads as described in JP-A-63-274944 and JP-A-63-274952. Further, compounds as described in the RD references cited above may be used.

In addition, the layers constituting the heat-developable photographic light-sensitive material and the dye-fixing element may contain a heat solvent, an antifoaming agent, a bactericide, an antimold agent, a colloidal silica, etc. These additives are further described in JP-A-61-88256 (pages 26 to 32), JP-A-3-11338 and JP-B-2-51496.

In the present invention, the heat-developable light-sensitive material and/or the dye-fixing element may contain an image formation accelerator. The image formation accelerator serves to accelerate the redox reaction of a silver salt oxidizing agent and a reducing agent, to accelerate the reaction such as the production or decomposition of a dye from a dye-providing substance and the release of a diffusible dye from a dye-providing substance, or to accelerate the migration of a dye from the heat-developable photosensitive material layer to the dye-fixing layer. From the standpoint of physicochemical function, the image formation accelerator can be classified as a base or base precursor, nucleophilic compound, high boiling organic solvent (oil), heat solvent, surfactant, silver or silver ion interacting compound, and the like. However, these groups of substances usually have multiple functions and exert some of these accelerating effects in combination. These image formation accelerators are further described in U.S. Patent 4,678,739 (columns 38 to 40).

Examples of the base precursors include salts of organic acid and base which undergo decarboxylation upon heating and compounds which undergo an intramolecular nucleophilic substitution reaction, a Lossen rearrangement or a Beckmann rearrangement to release amines. Specific examples of the base precursors are described in U.S. Patent Nos. 4,514,493 and 4,657,848.

In the system where heat development and dye transfer are carried out simultaneously in the presence of a small amount of water, a base and/or a base precursor is preferably incorporated into the dye fixing element in order to increase the durability of the heat-developable photosensitive material.

In addition to the above base precursors, a combination of a difficultly soluble metal compound and a compound capable of undergoing a complex formation reaction with metal ions constituting the difficultly soluble metal compound (i.e., a complex formation compound) as described in EP-A-210660 and U.S. Patent 4,740,445, and a compound which undergoes electrolysis to produce a base as described in JP-A-61-232451 can be used as the base precursor. In particular, the former is effective. The difficultly soluble metal compound and the complex formation compound are advantageously separated in the heat-developable, light-sensitive material and the dye-fixing element are incorporated.

In the present invention, the heat-developable photosensitive material and/or the dye-fixing element may contain various development stopping agents for maintaining an unchanged constant image quality against the fluctuation of the processing temperature and time during development.

The development stopping agent is a compound that rapidly neutralizes or reacts with a base after appropriate development to reduce the base concentration in the film to stop development, or a compound that interacts with silver or a silver salt after appropriate development to inhibit development. Specific examples of the development stopping agent include an acid precursor that releases an acid under heating, an electrophilic compound that undergoes a substitution reaction with an existing base under heating, a nitrogen-containing heterocyclic compound, and a mercapto compound and precursors thereof. These compounds are further described in JP-A-62-253159 (pages 31 to 32).

In the present invention, the support for the heat-developable light-sensitive material and the dye-fixing element is preferably a support material that can withstand the processing temperature. In general, photographic supports such as paper and synthetic high molecular compounds (film) are used, as described in Shashin Kogaku no Kiso - Ginen Shashin hen (Base of Photographic Engineering - Silver Salt Photoaraphy Edition), Society of Photographic Science and Technology of Japan, Corona Co., Ltd. 1979, pages 223 to 240). Examples of the support materials include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyvinyl chloride, polystyrene, polypropylene, polyimide, cellulose (e.g., triacetyl cellulose), support materials obtained by incorporating a pigment such as titanium oxide into these films, paper obtained in the process of film synthesis of polypropylene, mixed paper made from a synthetic resin pulp such as polyethylene and a natural pulp, Yankee paper, baryta paper, coated paper, particularly cast coated paper (metal, fabric, and glass).

These carrier materials can be used directly or in the form of a laminate with a synthetic, high molecular weight compound, such as polyethylene, on one or both sides of it.

In addition to these support materials, support materials described in JP-A-62-253159 (pages 29 to 31), JP-A-1-161236 (pages 14 to 17), JP-A-63-316848, JP-A-2-22651 and JP-A-3-56955 and U.S. Patent 5,001,033 can be used.

A hydrophilic binder, an oxide of a semiconducting metal such as alumina sol and tin oxide, carbon black and other antistatic agents can be applied to the surface of these substrates.

Examples of the methods for imagewise exposing the heat-developable photosensitive material to record an image thereon include a method which comprises directly photographing a landscape or people using a camera or the like, a method which comprises exposure through a reversal film or negative film using a printer or enlarger, a method which comprises scanning exposure of an original image through a slit using an exposure device in a copying machine, a method which comprises exposure with a light-emitting diode or various lasers excited by an electric signal representative of the image data, and a method which comprises exposure directly or through an optical system to image data which is output to an image display device such as CRT, liquid crystal display, electroluminescent display and plasma display.

Examples of light sources for recording an image on the heat-developable photosensitive material include natural light, a tungsten lamp, a light-emitting diode, a laser, CRT and other light sources as described in U.S. Patent 4,500,626, column 56 and JP-A-2-53378 and JP-A-2-54672.

Furthermore, a wavelength conversion element in which a non-linear optical material is combined with a coherent light source such as a laser can be used. to effect imagewise exposure. The nonlinear optical material is a material capable of developing nonlinearity between polarization and electric field, which is formed when a strong photoelectric field such as a laser is used. Inorganic compounds such as lithium niobate, potassium dihydrogen phosphate (KDP), lithium iodate and BaB₂O₄, urea derivatives, nitroaniline derivatives, nitropyridine N-oxide derivatives such as 3-methyl-4-nitropyridine N-oxide (POM), and compounds as described in JP-A-61-53462 and JP-A-62-210432 can be used. Examples of the wavelength conversion elements include a single crystal light guide type wavelength conversion element and a fiber type wavelength conversion element. All of these types of wavelength conversion elements can be effectively used.

Examples of the image data to which the present invention can be applied include image signals obtained from a video camera or an electronic still camera, television signals specified by National Television Signal Code (NTSC), image signals obtained by dividing an original image into numerous picture elements by means of a scanner, and image signals generated by computers such as CG and CAD.

The heat-developable photosensitive material and/or the dye-fixing member according to the present invention may contain an electrically conductive heating element layer such as a heater for heat development and diffusion transfer of the dye. In this embodiment, the heating element described in JP-A-61-145544 can be used.

The heating temperature in the heat development process is normally about 50°C to 250°C, particularly about 60°C to 180°C. The diffusion transfer of a dye may be carried out simultaneously with or after the heat development process. In the latter case, the transfer of a dye may be carried out at a heating temperature in the range of the heat development temperature to room temperature, particularly preferably 50°C to a temperature about 10°C lower than the heat development temperature.

The migration of a dye can be caused by heat alone. In order to accelerate the migration of a dye, a solvent can be used. As described in detail in U.S. Patents 4,704,345 and 4,740,445 and JP-A-61-238056, the system is preferably heated in the presence of a small amount of a solvent (particularly water) to simultaneously or continuously carry out the development and the transfer. In this method, the heating temperature is preferably from 50°C to a temperature lower than the boiling point of the solvent, for example, from 50°C to 100°C if the solvent is water.

Examples of solvents for accelerating development and/or diffusion and transfer of a dye to the dye-fixing layer include water and a basic aqueous solution containing an inorganic alkali metal salt or an organic base (these bases include those described with reference to the image formation accelerator). Further, a low-boiling solvent and a mixture of a low-boiling solvent and water or the above basic aqueous solution may be used. Furthermore, a surfactant, an antifogging agent, a difficultly soluble metal salt, a complexing compound, a preservative and a germicidal agent may be contained in these solvents.

As a solvent usable in the heat development and diffusion transfer processes, water is preferably used. The water may be any commonly used water. Specific examples of the water include distilled water, tap water, spring water and mineral water. In the heat development apparatus for the heat-developable photosensitive material and the dye-fixing element according to the present invention, the water may be consumed or recycled. In the latter case, the water discharged from the materials is reused. Further, an apparatus and water as described in JP-A-63-144354, JP-A-63-144355, JP-A-62-38460 and JP-A-3-210555 may be used.

These solvents may be intended for either or both of the heat-developable photosensitive material and the dye-fixing element.

The amount of these solvents to be used need not exceed their weight, corresponding to the maximum swellable volume of the coated film.

To provide these solvents for the heat-developable photosensitive layer or the dye-fixing layer, methods as described in JP-A-62-253159 (page 5) and JP-A-63-85544 can be used. Alternatively, these solvents may be previously contained either in one or more of the heat-developable photosensitive material and the dye-fixing element in the form of microcapsules or as a hydrate.

The temperature of the water intended for these photographic materials may be 30 to 60ºC, as described in JP-A-63-85544.

A hydrophilic heat solvent which remains solid at normal temperature but becomes soluble at an elevated temperature may be incorporated into the heat-developable photosensitive material and/or dye-fixing element to accelerate the migration of a dye. The layer into which the hydrophilic heat solvent is incorporated may be any photosensitive silver halide emulsion layer, interlayer, protective layer and dye-fixing layer, preferably a dye-fixing layer and/or its adjacent layers.

Examples of the hydrophilic heat solvent include ureas, pyridines, amides, sulfonamides, imides, alcohols, oximes and other heterocyclic groups.

Examples of heating in the developing and/or transferring process include a method which comprises bringing the material into contact with a heated block or plate, a hot plate, a hot printing device, a heat roller, a halogen lamp heater, an infrared lamp heater, or a heater with a far infrared lamp, and a method which comprises passing the material through a high-temperature atmosphere.

As a method for laminating the heat-developable photosensitive material and the dye-fixing element, a method as described in JP-A-61-147244 (page 27) can be used.

Processing of the photographic elements of the present invention can be carried out using any of various thermal development devices. For example, preferably, a device such as that described in JP-A-59-75247, JP-A-59-177547, JP-A-59-181353, JP-A-60-18951, JU-A-62-25944 (the term "JU-A" as used herein means a "published Japanese utility model application"), JP-A-6-95338 and JP-A-6-95267 can be used. Examples of commercially available thermal development devices for use in the present invention include Pictrostat 100, Pictrostat 200, Pictrography 3000 and Pictrography 2000 available from Fuji Foto Film Co., Ltd.

The present invention is further described in the following examples. All parts, percentages, ratios and the like are by weight, unless otherwise indicated.

EXAMPLES example 1

The preparation of light-sensitive silver halide emulsions is described below.

Light-sensitive silver halide emulsion (1) [Emulsion for the fifth layer (680 nm sensitive layer)]

To an aqueous solution having the formulations given in Table 1 which had been thoroughly stirred, solutions (I) and (II) having the formulations given in Table 2 were added simultaneously over 13 minutes. After 10 minutes, solutions (III) and (IV) having the formulations given in Table 2 were added simultaneously over 33 minutes to the mixture.

TABLE 1 composition

H2O 620 ml

lime-treated gelatine 20 g

KBr 0.3 g

NaCl 2g

Silver halide solvent (1) 0.030 g

Sulfuric acid (1 N) 16 ml

Temperature 45ºC TABLE 2 Silver halide solvent (1)

After 13 minutes had passed after the addition of the solution (III), 150 ml of a 0.350% aqueous solution of the following sensitizing dye (a) was added to the mixture in 27 minutes.

The emulsion was then rinsed and desalted by an ordinary method (pH was maintained at 4.1 with a precipitating agent (a)). To the emulsion was then added 22 g of lime-treated bone gelatin so as to adjust it to pH 6.0 and pAg 7.9. The emulsion was then chemically sensitized at a temperature of 60°C with the compounds shown in Table 3. As a result, 630 g of a monodisperse emulsion of cubic silver bromochloride grains having a variation coefficient of 10.2% and an average grain size of 0.20 µm was obtained. Precipitating agent (a) Precipitating agent (b) Sensitizing dye (a)

TABLE 3 composition used in chemical sensitization added amount

4-Hydroxy-6-methyl-1,3,3a,7-tetrazaindene 0.36 g

Sodium thiosulfate 6.75 mg

Antifoggant (1) 0.11 g

Preservative (1) 0.07 g

Preservatives (2) 3.13 g Antifogging agent (1) Preservatives (1) Preservatives (2) Preservatives (3)

Light-sensitive silver halide emulsion (2) [Emulsion for the third layer (750 nm sensitive layer)]

To an aqueous solution having the formulation given in Table 4, which had been thoroughly stirred, solutions (I) and (II) having the formulations given in Table 5 were added simultaneously over 18 minutes. After 10 minutes, solutions (III) and (IV) having the formulations given in Table 5 were added simultaneously over 24 minutes to the mixture.

TABLE 4 composition

H2O 620 ml

lime-treated gelatine 20 g

KBr 0.3g

NaCl 2g

Silver halide solvent I1) 0.030 g

Sulfuric acid (1N) 16 ml

Temperature 45ºC TABLE 5

The emulsion was then rinsed and desalted by an ordinary method (the pH was maintained at 3.9 with a precipitating agent (b). To the emulsion was then added 22 g of lime-treated bone gelatin (calcium content: 150 ppm or less). The emulsion was then redispersed at a temperature of 40°C. To the emulsion was then added 0.39 g of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene to adjust it to pH 5.9 and pAg 7.8. The emulsion was then chemically sensitized with the compounds shown in Table 6 at a temperature of 70°C. At the end of the chemical sensitization, the sensitizing dyes (2) and (3) were added to the emulsion in the form of a solution in methanol (the solution had the composition shown in Table 7). After the chemical sensitization, the emulsion was allowed to cool to a temperature of 40°C, after which 200 g of a gelatin dispersion of a stabilizer (1) described later was added thereto. The emulsion was thoroughly stirred and then recovered. As a result, 938 g of a monodisperse emulsion of cubic silver bromochloride grains having a variation coefficient of 12.6% and an average grain size of 0.25 µm was obtained.

TABLE 6 composition used in chemical sensitization added amount

4-Hydroxy-6-methyl-1,3,3a,7-tetrazaindene 0.39 g

Triethylthiourea 3.3 mg

Decomposition product of nucleic acid 0.39 g

NaCl 0.15g

Cl 0.12 g

Antifogging agent (2) 0.10 g

Preservative (1) 0.07 g

TABLE 7 Composition of the dye solution added amount

Sensitizing dye (2) 0.12 g

Sensitizing dye (3) 0.06 g

p-Toluenesulfonic acid 0.71 g

Methanol 18.7 ml Antifoggant (2) Sensitizing dye (2) Sensitizing dye (3)

Light-sensitive silver halide emulsion (3) [Emulsion for the first layer (810 nm sensitive layer)]

To an aqueous solution having the formulation given in Table 8, which had been thoroughly stirred, solutions (I) and (II) having the formulations given in Table 9 were added simultaneously over 18 minutes. After 10 minutes, solutions (III) and (IV) having the formulations given in Table 9 were added simultaneously over 24 minutes to the mixture.

TABLE 8 composition

H2O 620 ml

lime-treated gelatine 20 g

KBr 0.3 g

NaCl2 9

Silver halide solvent I1) 0.030 g

Sulfuric acid (1 N) 16 ml

Temperature 50ºC TABLE 9

The emulsion was then rinsed and desalted by an ordinary method (the pH was kept at 3.8 with a precipitating agent (a). To the emulsion was then added 22 g of lime-treated bone gelatin so as to adjust it to pH 7.4 and pAG 7.8. The emulsion was then chemically sensitized with the compounds shown in Table 10 at a temperature of 60°C. As a result, 680 g of a monodisperse emulsion of cubic silver bromochloride grains with a variation coefficient of 7.9% and an average grain size of 0.32 µm was obtained.

TABLE 10 composition used in chemical sensitization added amount

4-Hydroxy-6-methyl-1,3,3a,7-tetrazaindene 0.38 g

Triethylthiourea 3.10 mg

Antifoggant (2) 0.19 g

Preservative (1) 0.07 g

Preservatives (2) 3.13 g

The preparation of a gelatin dispersion of colloidal silver is described below.

To an aqueous solution having the formulation shown in Table 11 which had been thoroughly stirred, a solution having the formulation shown in Table 12 was added over 24 minutes. The emulsion was then flocculated with the precipitant (a). The resulting precipitate was then rinsed. To the emulsion was then added 43 g of lime-treated bone gelatin so as to adjust it to pH 6.3. As a result, 512 g of a gelatin dispersion of colloidal silver having an average grain size of 0.02 µm was obtained (the dispersion contains 2% silver and 6.8% gelatin).

Table 11 composition

H2O 620 ml

Dextrin 16 g

NaOH (5N) 41ml

Temperature 30ºC

TABLE 12 composition

H2O 135 ml

AgNO3 17 g

The preparation of a gelatin dispersion of hydrophobic additive is described below.

Gelatin dispersions of yellow dye-providing compound, magenta dye-providing compound and cyan dye-providing compound were prepared according to the formulations shown in Table 13. That is, various oil phase components were mixed at a temperature of about 70°C to prepare a uniform solution. To the solution were then added aqueous components heated to a temperature of about 60°C. The mixture was stirred and then subjected to dispersion at 1000 rpm for 10 minutes. To the dispersion was then added water. The mixture was then stirred to obtain a uniform dispersion. The gelatin dispersion of the cyan dye-providing compound was then repeatedly diluted and condensed with water by means of an ultrafiltration module (ultrafiltration module ACV-3050, available from Asahi Chemical Industry Co., Ltd.) so that the amount of ethyl acetate was reduced to 1/17.6 of the original amount shown in Table 13. TABLE 13

A gelatin dispersion of a reducing agent (2) was prepared according to the formulation shown in Table 14. Specifically, various oil phase components were mixed at a temperature of about 60°C to prepare a solution. To the solution were then added various phase components which had been heated to a temperature of about 60°C. The mixture was stirred and then subjected to dispersion with a homogenizer at 10,000 rpm for 10 minutes to obtain a uniform dispersion. Ethyl acetate was removed from the dispersion using a vacuum organic solvent removal device.

TABLE 14 Composition of the dispersion Oil phase

Reducing agent (2) 7.5 g

high boiling agent (1) 4.7 g

surfactant (1) 1.9 g

Ethyl acetate 14.4 ml

aqueous phase

Acid treated gelatine 10.0 g

Preservative (1) 0.02 g

Preservatives (3) 0.04 g

Sodium hydrogen sulfite 0.1 g

Water 136.7 ml

A gelatin dispersion of a stabilizer (1) was prepared according to the formulation shown in Table 15. Specifically, various oil phase components were mixed at room temperature to prepare a solution. To the solution were then added aqueous components heated to a temperature of about 40°C. The mixture was stirred and then subjected to dispersion at 10,000 rpm by means of a homogenizer for 10 minutes. To the dispersion was then added water. The mixture was then stirred to obtain a uniform dispersion.

TABLE 15 Composition of the dispersion Oil phase

Stabilizer (1) 4.0 g

Sodium hydroxide 0.3 g

Methanol 62.8g

high boiling solvent (4) 0.9 g

aqueous phase

decalcified gelatin (Ca content: 100 ppm or less) 10.0 g

Antifoggant (1) 0.04 g

A gelatin dispersion of zinc hydroxide was prepared according to the formulation given in Table 16. Specifically, various components were mixed to prepare a solution. The solution was then subjected to dispersion with glass beads having an average grain diameter of 0.75 mm by means of a mill for 30 minutes. The glass beads were then removed to obtain a uniform dispersion. (The zinc hydroxide grains used had an average grain size of 0.20 µm.)

TABLE 16 Composition of the dispersion

Zinc hydroxide 15.9 g

Carboxymethylcellulose 0.7 g

Sodium polyacrylate 0.07 g

lime-treated gelatine 4.2 g

Water 100ml

high boiling solvent (4) 0.4 g

The following describes the preparation of a gelatin dispersion of a matting agent to be incorporated into the protective layer. That is, a solution of PMMA in methylene chloride was added to gelatin with a small amount of a surfactant. The mixture was then stirred at a high speed to effect dispersion. Methylene chloride was then added using a vacuum solvent removal device to obtain a uniform dispersion with an average particle size of 3.6 µm. Cyan dye-providing compound (1) Cyan dye-producing compound (2) Magenta dye-producing compound (1) yellow dye-producing compound (1 Reducing agent (1) Antifogging agents (3) Antifogging agents (4) surfactant (1) high boiling solvent (1) high boiling solvent (2) high boiling solvent (3) Dye (a) Reducing agents (2) Stabilizer (1) high boiling organic solvent (4) (same as the preservative) (2)) surfactant (2) surfactant (3) surfactant (4)

The above materials were used to prepare a heat-developable photosensitive material 100 shown in Tables 17 and 18. TABLE 17 Main components of heat-developable color photosensitive material 100

Carrier (polyethylene laminated paper; thickness: 131 µm)

Note Additives to be added in small quantities, e.g. preservatives are omitted. surfactant (2) surfactant (3) surfactant (4) water-soluble polymer (1) Sensitizing dye (4) Antifogging agents (5)

Film hardener (1)

CH2 =CHSO2 CH2 SO2 CH=CH2

The preparation of a photosensitive material 101 is described below.

Photosensitive material 101 was prepared in the same manner as photosensitive material 100 except that the yellow dye-providing compound (1) contained in the yellow dispersion incorporated in the first layer was replaced with 9.9 g of a yellow dye-providing compound (2) having the following structural formula and 6.2 g of a development accelerator having the following structural formula were emulsion-dispersed in an oil phase of the yellow dispersion shown in Table 13. Yellow dye-providing compound (2) Development accelerator

The Preparation of photosensitive materials 102 to 115 is described below.

First, the preparation of a fine emulsion of grains with a high silver chloride content (1a) to (1g) is described.

To an aqueous solution having the formulation given in Table 18, which had been thoroughly stirred, were simultaneously added solutions (I) and (II) having the formulations given in Table 19 over 4 minutes. After 5 minutes, solutions (III) and (IV) having the formulations given in Table 20 were simultaneously added to the mixture over 8 minutes.

After two minutes had passed after the addition of solutions (III) and (IV), 0.7 g of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene was added to the mixture. The emulsion was then rinsed and desalted by an ordinary method (pH was maintained at 3.9 with a precipitating agent (a)). To the emulsion was then added 22 g of lime-treated bone gelatin so as to adjust it to pH 5.7 and pAg 6.8. As a result, 530 g of a monodisperse emulsion (1a) of silver chloride grains having an average grain size of 0.08 µm was obtained.

Table 18 composition

H2O 630 ml

lime-treated gelatine 10 g

NaCl 0.15g

Temperature 38ºC TABLE 19

An emulsion (1b) was prepared in the same manner as the emulsion (1a) except that the solutions (I) to (IV) having the formulations shown in Table 20 were added. As a result, 530 g of a monodisperse emulsion of silver bromochloride grains (Br content: 10 mol%) having an average grain size of 0.08 µm was obtained. TABLE 20

An emulsion (1c) was prepared in the same manner as the emulsion (1a) except that the solutions (I) to (IV) having the formulations shown in Table 21 were added. As a result, 530 g of a monodisperse emulsion of silver bromochloride grains (Br content: 20 mol%) having an average grain size of 0.08 µm was obtained. TABLE 21

An emulsion (1b) was prepared in the same manner as the emulsion (1d) except that the solutions (I) to (IV) were added with the formulations shown in Table 22. As a result, 530 g of a monodisperse emulsion of silver bromochloride grains (Br-Gehall: 40 mol%) having an average grain size of 0.08 µm was obtained. TABLE 22

Emulsions (1e), (1f) and (1g) having an average grain size of 0.12 µm, 0.20 µm and 0.05 µm, respectively, were prepared in the same manner as the emulsion (1a), except that the temperature of the aqueous solution shown in Table 18 was 42°C, 50°C and 32°C, respectively. The amount of these emulsions was 530 g, respectively.

Photosensitive Materials 102 to 115 were prepared from these emulsions in the same manner as Photosensitive Material 100, except that the change shown in Table 23 was made. TABLE 23

These photosensitive materials 100 to 115 were each processed with a digital color printer Fujix Pictrography Type PG-3000 available from Fuji Photo Film Co., Ltd., with PG-SG for PG-3000 as a dye fixing material to effect image output. Specifically, a solid gray image was first formed in an atmosphere of 25ºC and 50% RH. The color tone of the image was measured in appropriately adjusted. Under the same exposure conditions, images were formed in an atmosphere of 15ºC and 50% relative humidity and of 30ºC and 50% relative humidity. The gray images obtained in these atmospheres were then measured for density by means of a reflection densitometer of the X-rite 304 type available from X-rite Corp.

The change in color balance between the sample prepared at 15ºC and 50% relative humidity and the sample prepared at 30ºC and 50% relative humidity was visually evaluated.

Then, using an exposure device containing an optical system as described in Fig. 2 of JP-A-6-127021, these photographic light-sensitive materials were subjected to sensitivity measurement under the conditions shown in Table 24 at 15°C and 50% RH, at 25°C and 50% RH and at 30°C and 50% RH in an environmental test chamber to determine the gradation γY, γM and γC at 25°C and 50% RH and the temperature dependence of the sensitivity ΔSY, ΔSM and ΔSC.

A gray image having Y, M and C color reflection densities of 1.0 was formed on each of these photographic light-sensitive materials under standard image forming conditions at 25ºC and 50% relative humidity under the conditions shown in Table 25. Thereafter, the heat treatment temperature was changed by +5ºC and -5ºC. The other conditions were not changed. Under these conditions, a grain image was formed on each of these photographic light-sensitive materials. The images thus obtained were measured for the change in color densities using an X-rite 304 reflection densitometer.

TABLE 24

Beam intensity on the photosensitive photographic material Intensity of the 675 nm laser beam: 60 uW Intensity of the 755 nm laser beam: 250 uW Intensity of the 815 nm laser beam: 250 uW

Scanning line density 1600 dpi (63 lines per mm)

Beam diameter 85 ± 8.5 um in the direction of main scanning 55 ± 5.5 um in the direction of sub-scanning

Exposure time 667 us per loader Repetition rate: 1.33 ms

Exposure wavelength 675, 755, 815 nm (laser beam)

Exposure 1 log E change per 2.5 cm in the sub-scan direction

Method for changing exposure Light emission time modulation (as described in JP-A-5-199372)

The results are given in Table 25. TABLE 25

The results of Table 25 show that the photosensitive materials of the present invention show a smaller change in color image balance against the change in ambient temperature during exposure than the comparative photosensitive materials. It is thus apparent that the photosensitive materials of the present invention are excellent. It is also shown that the photosensitive materials of the present invention show a smaller change in image density against the change in processing temperature.

As mentioned above, the photosensitive materials of the present invention have a minimized change in image density against the change in processing temperature during heat development and a minimized change in color image balance against the change in environmental conditions (particularly temperature) during exposure, thereby obtaining an image having an excellent discrimination between image area and non-image area.

Claims (4)

1. A heat-developable color photosensitive material comprising a support on which are provided at least two photosensitive silver halide layers having a spectral sensitivity peak in a different wavelength range of 700 nm or more, in which the at least two photosensitive silver halide layers are each combined with a compound which gives a dye having a different color tone, wherein the layer having a spectral sensitivity peak in the longest wavelength and/or a photoinsensitive intermediate layer adapted thereto further contains (a) a high silver chloride emulsion of fine grains having a silver chloride content of 80 mol% or more and an average size of 0.15 µm or less or (b) a readily soluble silver salt compound. 2. The heat-developable color photosensitive material as claimed in claim 1, wherein the compound which gives a dye combined with the layer having a spectral sensitivity peak in the longest wavelength is a compound represented by the following formula (1): wherein Dye represents a dye group or dye precursor group represented by the following formula (2); Y represents a group which makes a difference in the diffusibility of the dye component in accordance or counter-accordance with a reduction reaction of photosensitive silver halide having an imagewise latent image to silver; X represents a single bond or a bonding group; p is an integer of 1 or more; and q is 1 or 2, with the proviso that when p is 2 or more, or if q is 2, the several dye groups or ((Dye)p - X) groups can be the same or different: wherein R³ represents a substituent selected from the group consisting of a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, an alkyl group, an aralkyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an amino group, an acylamino group, a sulfonylamino group, an acyl group, a sulfonyl group, a carbamoyl group, a sulfamoyl group, a ureido group, an alkylthio group and an arylthio group; R¹ and R² each independently represent a hydrogen atom or the substituent defined in R³; and n is an integer of 0 to 5 with the proviso that when n is 2 to 5, the plural R³ groups may be the same or different; and Dye and X are bonded together to any of the groups R¹, R² and R³. 3. The heat-developable color light-sensitive material as claimed in claim 1, wherein the easily soluble silver salt compound is silver nitrate, silver fluoride, silver perchlorate, silver hexafluorophosphate(V) or potassium dicyanargentate(I). 4. The heat-developable color light-sensitive material as claimed in claim 1, wherein the easily soluble silver salt compound is silver nitrate or silver fluoride.