Image forming method

Abstract

 Disclosed is an image forming method, which comprises subjecting a light-sensitive silver halide photographic material having at least one photographic constituent layer on a support, said material having at least one of inorganic sulfur or polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond as the constituent of the heterocyclic ring to exposure for a time of 10⁻⁴ sec. or shorter at any stage until said photographic constituent layer of the light-sensitive silver halide photographic material is formed, and then to developing processing.

Description

BACKGROUND OF THE INVENTION

[0001] This invention relates to a method for obtaining an image having a gradation from a soft information recorded in a magnetic medium, etc. by use of a light-sensitive silver halide photographic material, particularly to a method for obtaining a stable image with small fluctuation of sensitivity and gradation.

[0002] In the prior art, improved techniques of latent image stability are disclosed in U.S. Patents 4,374,196, 4,378,426, 4,423,140, 4,451,557, Japanese Unexamined Patent Publications Nos. 183,647/1989, 257,947/1989. Japanese Unexamined Patent Publication No. 18,547/1990 discloses improvement of density change with lapse of time during scanning exposure with silver halide grains composed mainly of silver chloride in which the silver bromide containing layer is localized, but further improvement of stability has been desired.

SUMMARY OF THE INVENTION

[0003] An object of the present invention is to provide a light-sensitive photographic method which can obtain an image of stable quality with extremely small fluctuation of sensitivity and gradation after exposure in a method for forming an image by short time exposure by use of a laser, etc., and at the same time an image forming method by use of the light-sensitive material.

[0004] The object of the present invention has been accomplished by an image forming method, which comprises subjecting a light-sensitive silver halide photographic material having at least one photographic constituent layer on a support, said material having at least one of inorganic sulfur or polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond as the constituent of the heterocyclic ring to exposure for a time of 10⁻⁴ sec. or shorter at any stage until said photographic constituent layer of the light-sensitive silver halide photographic material is formed, and then to developing processing.

DETAILED DESCRIPTION OF THE INVENTION

[0005] The term "inorganic sulfur" as herein used means so called sulfur of single substance which forms no compound with other elements. Therefore, sulfur containing compounds known as photographic additives in this field of art, such as sulfides, sulfuric acid (or salts thereof), sulfites (or salts thereof), thiosulfates (or salts thereof), sulfonic acid (or salts thereof), thioether compounds, thiourea compounds, mercapto compounds, sulfur containing heterocyclic compounds, etc. are not included within "inorganic sulfur" in the present invention.

[0006] Single substance of sulfur which is used as "inorganic sulfur" to be used in the present invention has been known to have some allotropes, and any allotrope thereof may be used. Among these allotropes, one which is stable at room temperature is α-sulfur belonging to the rhombic system, and in the present invention, the α-sulfur should be preferably used.

[0007] When "inorganic sulfur" according to the present invention is added, it may be added as the solid as such, but it should be preferably added as a solution. Inorganic sulfur is insoluble in water, but has been known to be soluble in carbon disulfide, sulfur chloride, benzene, diethyl ether, ethanol, etc., and it should be preferably added as a solution in these solvents. Among these solvents for inorganic sulfur, ethanol may be used particularly preferably from such standpoints as handleability, photographic deleterious effects, etc.

[0008] The optimum amount of inorganic sulfur added depends on the kind of the silver halide emulsion applied and greatness of the effect expected, but may be 10⁻⁵ to 10 mg per mole of silver halide. The amount added may be added all at once or in plural divided portions.

[0009] The photographic layer in which inorganic sulfur according to the present invention is added contains (1) an organic compound containing a polysulfide bond with at least 3 sulfur atoms linked, or (2) a compound containing a heterocyclic ring containing at least two thioether bonds and at least one disulfide bond in the molecular structure (hereinafter called the sulfide compound according to the present invention), of which preferably used is a chain or cyclic compound containing a polysulfide bond with at least 3 sulfur atoms linked, and a compound represented by the formula [A] or the formula [B]:

[0010] In the formulae, R₁, R₂ each represent a group which can be substituted on benzene ring or cyclohexane ring, and n represents an integer of 0 to 4. Z₁, Z₂ each represent a group of atoms necessary for formation of a 5- to 8-membered heterocyclic ring containing at least 2 ether bonds or at least one disulfide bond.

[0011] When the sulfide compound according to the present invention is added, a solid may be also added as such, but preferably as a solution.

[0012] The optimum amount of the sulfide compound according to the present invention added depends on the kind of the silver halide emulsion applied and the greatness of the greatness of the effect expected, etc., but may be 5 x 10⁻⁷ to 10⁻³ mole per mole of silver halide. The amount added may be added all at once or in plural divided portions.

[0013] The photographic layer in which the inorganic sulfur, the sulfide compound according to the present invention is added may be either of the light-sensitive silver halide emulsion layer and the non-light-sensitive hydrophilic colloidal layer (in this case, supplied to the silver halide emulsion layer during coating), but preferably the light-sensitive silver halide emulsion layer.

[0014] The timing when the sulfide compound according to the present invention is added into the silver halide emulsion layer may be at any desired step before formation of the silver halide emulsion layer.

[0015] More specifically, it may be any timing before formation of silver halide grains, during formation of silver halide grains, between completion of formation of silver halide grains and initiation of chemical sensitization, before initiation of chemical sensitization, during chemical sensitization, on completion of chemical sensitization and between completion of chemical sensitization and coating. Preferably, it is added on initiation of chemical sensitization, during chemical sensitization, until completion of chemical sensitization.

[0016] Chemical sensitization initiation step refers to the step when a chemical sensitizer is added, and the time when the chemical sensitizer is added in said step is the chemical sensitization initiation time.

[0017] The above-mentioned chemical sensitization can be stopped according to the method known in this field of art. As the method for completing chemical sensitization, there have been known the method of lowering the temperature, the method of lowering pH, the method using a chemical sensitization stopper, etc. but in view of stability of the emulsion, etc., the method of using a chemical sensitization stopper is preferred. As the chemical sensitizing stopper, halides (e.g. potassium bromide, sodium chloride, etc.), organic compounds known as antifoggants or stabilizers (e.g. 7-hydroxy-5-methyl-1,3,4,7a-tetrazaindene, etc.) have been known.

[0018] These can be used either individually or as a combination of plural compounds.

[0019] The inorganic sulfur, the sulfide compound according to the present invention may be added in the step of stopping chemical sensitization, but "the step of stopping chemical sensitization" as herein mentioned refers to the step of adding the chemical sensitization stopper as described above. In this case, the timing when the sulfide compound according to the present invention may be substantially during the step of stopping chemical sensitization, including specifically at the same time as addition of the chemical sensitizing stopper or within around 10 minutes before or after the addition, preferably addition at the same time or within around 5 minutes before or after the addition.

[0020] In the following, representative examples of the sulfide compound according to the present invention are set forth, but they are merely exemplary and not limitative of the present invention.

[0021] These sulfide compounds can be synthesized according to the methods described in Journal of the American Chemical Society (J. Am. Chem. Soc.) (104)6045(1982), the same (107)3871(1985), Journal of Organic Chemistry (J. Org. Chem.)(49)1221(1984), the same (37)4196(1972), the same (41)2465(1976), the same(46)2072(1981), Journal of the Chemical Society (J. Chem. Soc.)2901(1965), the same 1582(1929), the same 187(1941), Chemistry Letters (Chem. Lett.) 349(1986), Bulletin of the Chemical Society of Japan (Bull. Chem. Soc. Japan) (61)1647(1988), etc.

[0022] The silver halide grains contained in the silver halide emulsion according to the present invention may be either of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver chloroiodobromide, and may be also a mixture of these grains.

[0023] Among them, a silver chloride containing emulsion is preferred, particularly a high silver chloride content emulsion preferred with respect to remarkably excellent rapid processability.

[0024] The high silver chloride content silver halide emulsions grains have a content of 80 mole % or more, preferably 90 mole % or more of silver chloride, with the silver bromide content being 20 mole % or less, preferably 10 mole % or less, with the silver iodide content being preferably 0.5 mole % or less. More preferably, the silver bromide content should be 0 to 5 mole %.

[0025] In the silver halide emulsion layer containing silver halide grains having a silver chloride content of 90 mole % or more, the ratio of the silver halide grains having a silver chloride content of 90 mole % or more occupied in the total silver halide grains contained in said emulsion layer may be 60 % by weight or more, preferably 80 % by weight or more. Further, when high silver chloride content silver halide grains are employed, when combined with inorganic sulfur, the composition of the silver halide grains may be uniform from the inner portion of the grains to the outer portion, or the compositions of the inner portion or the outer portion of the grains may be different. When the composition of the inner portion of the grains is different from that of the outer portion, the composition may be varied continuously, or made incontinuous.

[0026] The grain size of the silver halide grains to be used in the present invention is not particularly limited, but in view of rapid processability and sensitivity, etc., other photographic performances, etc., may be preferably within the range of 0.2 to 1.6 µm, more preferably 0.25 to 1.2 µm.

[0027] The above-mentioned grain size can be measured according to various methods generally employed in said field of art. Representative methods are described in "Analytical Method of Grain Size" of Labland, A.S.T.M. Symposium on Light Microscopy, 1955, p.94122 or Chapter 2 of "Theory of Photographic Process" co-written by Mieth and James, 3rd ed., Macmillan (1966).

[0028] The grain size can be measured by the projected area of the grain or by using directly an approximate value.

[0029] When the grains are of substantially the same shapes, the grain size distribution can be represented considerably as the diameter or the projected area.

[0030] The grain size distribution of the silver halide grains according to the present invention may be either poly-dispersed or mono-dispersed, but preferably mono-dispersed. More preferably, they are preferably mono-dispersed silver halide grains with a fluctuation coefficient of 0.22 or less, more preferably 0.15 or less in the grain size distribution of silver halide grains.

[0031] Here, the fluctuation coefficient is a coefficient representing the breadth of grain size distribution and is defined by the following formula:


S = standard deviation of grain distribution

[0032] Here, ri represents the grain size of individual grains, ni its number, and the grain size as herein mentioned represents to its diameter in the case of spherical silver halide grains, or the diameter when the projected image is calculated to the circular image with the layer area in the case of cubic grains or grains with other shapes than spherical.

[0033] The silver halide grains to be used in the emulsion of the present invention may be obtained according to any of the acidic method, the neutral method, the ammonia method. Said grains may be grown all at once or after formation of seed grains.

[0034] The method for forming seed grains and the growth method may be either the same or different.

[0035] As the system for allowing a soluble silver salt to react with a soluble halogenic salt, there may be employed either of the normal mixing method, the reverse mixing method, the simultaneous mixing method, or a combination of them, etc., but one obtained by the simultaneous mixing method is preferred. Further, as one system of the simultaneous mixing method, there can be also used the pAg-controlled double jet method described in Japanese Unexamined Patent Publication No. 48521/1979.

[0036] Further, if necessary, a silver halide solvent such as thioether, etc. may be also employed.

[0037] Also, a compound such as mercapto group containing compounds, nitrogen containing heterocyclic compounds or sensitizing dyes may be added during formation of silver halide grains or after completion of grain formation.

[0038] The shape of the silver halide grains according to the present invention may be any desired one.

[0039] A preferable example is a cubic body having the {100} face as the crystal surface. It is also possible to make octahedral, tetradecahedral, dodecahedral bodies, etc. according to the methods described in literatures such as U.S. Patents 4,183,756, 4,225,666, Japanese Unexamined Patent Publication No. 26,589/1980, Japanese Patent Publication No. 42737/1980 or The Journal of Photographic Science (J. photogr. Sci.), 21, 39 (1973), etc., and these can be also used.

[0040] Further, grains having the twin crystal surface may be also used.

[0041] The silver halide grains according to the present invention may be grains having a single shape or a mixture of grains having various shapes.

[0042] The silver halide grains to be used in the emulsion of the present invention, in order to impart preferable gradation characteristics under the short time exposure condition during the process of forming and/or growing grains, can add metallic ions by use of iron salt, cadmium salt, zinc salt, lead salt, thallium salt, iridium salt or complex thereof, rhodium salt or complex thereof, iron salt or complex salt to be included internally of the grains and/or on the surface of grains, and also can be placed in a reducing atmosphere to impart reducing sensitizing nuclei internally of the grains and/or onto the surface of grains.

[0043] The emulsion of the present invention may have unnecessary soluble salts removed after completion of the growth of the silver halide grains, or may contain them as such.

[0044] When said salts are to be removed, it can be practiced on the basis of the description in Research Disclosure No. 17643.

[0045] The silver halide grains to be used in the emulsion of the present invention may be grains with latent images being formed primarily on the surface, or alternatively grains with those primarily internally of the grains. Preferably, they are grains with latent images being formed primarily on the surface.

[0046] In the present invention, known chemical sensitizers such as chalocogenide sensitizers can be used.

[0047] In the present invention, further reducing sensitization can be used in combination. The reducing agent is not particularly limited, but known ferrous chloride, thiourea dioxide, hydrazine, polyamine, etc. may be employed. Also, noble metal compounds, such as platinum compounds, palladium compounds, etc. can be employed.

[0048] As the gold sensitizer, the oxidation number of gold may be either monovalent or trivalent, and also other kinds of gold compounds may be employed. Representative examples may include, chloroaurates, potassium chloroaurate, auric trichloride, potassium auric thiocyanate, potassium iodoaurate, tetracyanoauric azide, ammonium aurothiocyanate, pyridyltrichlorogold, gold sulfide, gold selenide, etc.

[0049] The amount of the gold sensitizer added depends on various conditions, but as a measure, 10⁻⁸ to 10⁻¹ mole, preferably 10⁻⁷ to 10⁻² mole, per mole of silver halide. These compounds may be added at any timing, namely during formation of grains, during physical ripening, during chemical ripening and after completion of chemical ripening. When a gold compound is employed in the present invention, a light-sensitive material having more excellent latent image stability can be obtained.

[0050] The emulsion of the present invention can be spectrally sensitized to a desired wavelength region by use of a dye known as the sensitizing dye in the field of photography, and said sensitizing dye may be used either singly or as a combination of two or more kinds.

[0051] Together with the sensitizing dye, there may be also incorporated a dye having itself no spectral sensitizing action, or a color potentiating sensitizer which is a compound absorbing substantially no visible light and potentiates the sensitizing action of the sensitizing dye.

[0052] In the emulsion of the present invention, known compounds which have been known as antifoggants or stabilizers in the field of photography can be added.

[0053] In the present invention, a nitrogen containing heterocyclic compound (hereinafter called inhibitor) with a solubility product with silver ions (Ksp) of 1 x 10⁻¹⁰ or less, preferably 1 x 10⁻¹¹ or less may be effectively employed. For measurement, calculation of the solubility product, reference can be made to "New Experimental Chemistry Course Vol. 1" (Maruzen) p. 233 - 250.

[0054] The inhibitor according to the present invention is inclusive of the compounds described in, for example, (Chemical and Pharmaceutical Bulletin) (Tokyo) Vol. 26, 314 (1978), Japanese Unexamined Patent Publication No. 79436/1980, Berichte der Deutschen Chemischen Geselldraft) 82, 121 (1948), U.S. Patents 2,843,491, 3,017,270, 940,169, Japanese Unexamined Patent Publication No. 102639/1976, Journal of the American Chemical Society, 44, 1502 - 1510, Beilsteins Handbuch der Organischen Chemie, 26, 41, 58, etc., and they can be also synthesized according to the methods as described in these literatures.

[0055] Further, when a purine derivative compound or a mercapto group containing compound represented by the formula [II] shown below is used as the above-mentioned inhibitor, further excellent effect can be used by using inorganic sulfur in combination.

[0056] Formula [II]

wherein Zo is a heterocyclic residue, M hydrogen atom, an alkali metal atom or ammonium.

[0057] The inhibitor according to the present invention can be used either singly or as a combination of two or more kinds, and further may be used in combination with other stabilizers than the inhibitors according to the present invention or antifoggants.

[0058] The exposure time as mentioned in the present application refers to the time from when reaching 1/2 of the maximum time to when becoming 1/2 of the maximum value after attenuation in the change with time in intensity of light in such as flash exposure, while, as in the case of scanning exposure by a laser beam, it is defined as the exposure time by:
   (diameter of light flux)
   scanning speed
wherein the outer peripheral of the light flux is made at the place where the light intensity becomes 1/2 of the maximum value in the spatial change of the intensity of light flux, and the distance between the two points where the line which is in parallel to the scanning line and passes the point where the light intensity becomes the maximum is crossed with the outer peripheral of the light flux is made the diameter of the light flux.

[0059] In the scanning exposure by use of a linear light source, it may be also considered similarly as the laser beam as described above.

[0060] As to the kind of light source, there can be employed all of light sources known in the art such as xenon discharge tube, cathode ray tube (CRT), emission diode, tungsten halogen lamp, mercury high pressure discharge tube, laser, etc. Among them, it is preferable to use a gas laser such as helium-neon, argon, helium-cadmium, etc., a semiconductor layer such as gallium-arsenic-phosphorus, etc., and a combination of a non-linear optical device therewith.

[0061] As the laser printer device which can be considered applicable to such system, there may be included those as described in Japanese Unexamined Patent Publications Nos. 4071/1980, 11062/1984, Japanese Patent Publications Nos. 14963/1981, 40822/1981, European Patent No. 77410, Technical Report of Society of Electronic Communication of Japan Vol. 80, No. 244 and Movie and Television Technology 1984/6 (382), p. 34 - 36, etc.

[0062] When the present invention is applied to a color light-sensitive material, known dye forming couplers can be used.

[0063] The diffusion resistant yellow coupler to be used for the light-sensitive material of the present invention can be represented by the formula [Y] shown below:

[0064] In the formula, R₁ represents a halogen atom or an alkoxy group. R₂ represents hydrogen atom, a halogen atom or an alkoxy group which may also have substituents. R₃ represents an acylamino group, an alkoxycarbonyl group, an alkylsulfamoyl group, an arylsulfamoyl group, an arylsufonamide group, an alkylureido group, an arylureido group, a succinimide group, an alkoxy group, or an aryloxy group which may also have substituents. Z₁ represents an eliminable group during coupling with the oxidized product of a color developing agent.

[0065] In the present invention, as the magenta dye image forming coupler, the couplers represented by the formulae [M] and [MI] shown below can be preferably used.

[0066] In the formula, Ar represents an aryl group, Ra₁ hydrogen atom or a substituent, Ra₂ a substituent. Y represents hydrogen atom or a substituent eliminable through the reaction with the oxidized product of a color forming developing agent, W -NH-, -NHCO- (N atom is bonded to the carbon atom of pyrazolone nucleus) or -NHCONH-, and m is an integer of 1 or 2. Preferable examples of the compound represented by the formula [M] are as shown below.

[0067] In the magenta coupler represented by the formula [MI]:

[0068] Za represents a group of non-metallic atoms necessary for formation of a nitrogen containing heterocyclic ring, and the ring formed by said Za may also have a substituent. X represents hydrogen atom or a substituent eliminable through the reaction with the oxidized product of a color developing agent.

[0069] Ra represents hydrogen atom or a substituent.

[0070] Examples of the above-mentioned Ra may include halogen atoms, alkyl groups, cycloalkyl groups, alkenyl groups, cycloalkynyl groups, alkynyl groups, aryl groups, heterocyclic groups, acyl groups, sulfonyl groups, sulfinyl groups, phosphonyl groups, carbamoyl groups, sulfamoyl groups, cyano groups, spiro compound residues, bridged hydrocarbon compound residues, alkoxy groups, aryloxy groups, heterocyclicoxy groups, siloxy groups, acyloxy groups, carbamoyloxy groups, amino groups, acylamino groups, sulfonamide groups, imide groups, ureido groups, sulfamoylamino groups, alkoxycarobonylamino groups, aryloxycarbonylamino groups, alkoxycarbonyl groups, aryloxycarbonyl groups, alkylthio groups, arylthio groups, heterocyclicthio groups.

[0071] As the cyan image forming coupler, the couplers represented by the formulae [E], [F] shown below can be preferably used.

[0072] In the formula, R_1E represents an aryl group, a cycloalkyl group or a heterocyclic group. R_2E represents an alkyl group, an aryl group, a cycloalkyl group or a heterocyclic group. R_3E represents hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. Z_1E represents hydrogen atom, a halogen atom, or an eliminable group through the reaction with the oxidized product of an aromatic primary amine type color developing agent.

[0073] In the formula, R_4F represents an alkyl group (e.g. methyl, ethyl, propyl, butyl, nonyl and the like). R_5F represents an alkyl group (e.g. methyl, ethyl and the like). R_6F represents hydrogen atom, a halogen atom (e.g. fluorine, chlorine, bromine and the like) or an alkyl group (e.g. methyl, ethyl and the like). Z_2F represents hydrogen atom, a halogen atom or an eliminable group through the reaction with the oxidized product of an aromatic primary amine type color developing agent.

[0074] As the hydrophilic colloid for dispersing the silver halide of the present invention, it is advantageous to use gelatin, but also other hydrophilic colloids can be also used.

[0075] Examples of preferable hydrophilic colloids are most generally gelatins such as alkali-treated gelatin or acid-treated gelatin, etc., or a part of such gelatins may be replaced with gelatin derivatives such as phthalated gelatin, phenylcarbamoyl gelatin, albumin, agar, gum arabic, alginic acid, partially hydrolyzed cellulose derivatives, partially hydrolyzed polyvinyl acetate, polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone and copolymers of these vinyl compounds.

[0076] In the light-sensitive silver halide photographic material, various known additives for photography can be contained. Examples of such additives may include UV-ray absorbers (e.g. benzophenone type compounds and benzotriazole type compounds, etc.), dye image stabilizers (e.g. phenol type compounds, bisphenol type compounds, hydroxycouromane type compounds, bisspirocouromane type compounds, hydantoin type compounds, and dialkoxybenzene type compounds, etc.), antistaining agents (e.g. hydroquinone derivative, etc.), surfactants (e.g. sodium alkylnaphthalenesulfonate, sodium alkylnaphthalenbenzenesulfonate, sodium alkylsuccinate sulfonate, polyalkylene glycol, etc.), water-soluble anti-irradiation dyes (e.g. azo type compounds, styryl type compounds, triphenylmethane type compounds, oxonol type compounds and antharaquinone type compounds, etc.), film hardeners (e.g. halogenic s-triazine type compounds, vinylsulfone type compounds, acryloyl type compounds, ethyleneimino type compounds, N-methylol type compounds, epoxy type compounds and water-soluble aluminum salts, etc.), film property improvers (e.g. glycerine, fatty polyhydric alcohols, polymer dispersions (latices), solid/or liquid paraffins, and colloidal silica, etc.), fluorescent brighteners (e.g. diaminostilbene type compounds) and various oil-soluble coating materials, etc.

[0077] As the photographic layer constituting the light-sensitive silver halide material of the present invention, in addition to various emulsion layers, there can be provided conveniently the respective layers such as subbing layer, intermediate layer, yellow filter layer, UV-ray absorber layer, protective layer, antihalation layer, etc.

[0078] As the support of the light-sensitive silver halide photographic material of the present invention, there can be conveniently used a support such as paper, glass, cellulose acetate, cellulose nitrate, polyester, polyamide, polystyrene, etc., or a plastered product of two or more kinds of substrates such as a laminate of a paper and a polyolefin (e.g. polyethylene and polypropylene, etc.), etc. depending on the purpose.

[0079] The support is generally subjected to various surface treatments for improvment of adhesion to the silver halide emulsion layer. For example, one applied with such surface treatment as roughening of the surface by mechanical treatment or treatment with an organic solvent, electron shock treatment or flame treatment, etc., or subbing treatment to provide a subbing layer.

[0080] The light-sensitive silver halide photographic material of the present invention can form an image by performing the developing processing known in this field of art.

[0081] As the monochromatic developing agent to be used in the present invention, those described in "The Theory of Photographic Process" written by T.H. James, 4th ed., p 291 - 326 can be employed.

[0082] The present invention is described in more detail by referring to Examples, but the embodiments of the present invention are not limited to these.

Example - 1

[Method for preparing silver halide emulsion]

[0083] Into 1000 ml of a 2 % aqueous gelatin solution maintained at a temperature of 40 °C were added at the same time (Solution A) and (Solution B) shown below over 30 minutes while controlling pAg=6.5 and pH=3.0, and further (Solution C) and (Solution D) at the same time over 90 minutes while controlling pAg=7.3 and pH=5.5.

[0084] At this time, K₂TrCl₆ was added to an amount of 5 x 10^-7 mole per mole of silver halide. The pAg was controlled according to the method described in Japanese Unexamined Patent Publication No. 45437/1984, and the pH by use of an aqueous solution of sulfuric acid or sodium hydroxide.

[0085] (Solution A)

Sodium chloride

3.42 g

Potassium bromide

0.03 g

Water added to

200 ml

[0086] (Solution B)

Silver nitrate

10 g

Water added to

200 ml

[0087] (Solution C)

Sodium chloride

102.7 g

Potassium bromide

1.0 g

Water added to

600 ml

[0088] (Solution D)

Silver nitrate

300 g

Water added to

600 ml

[0089] After completion of addition, the mixture was desalted by use of a 5 % aqueous solution of Demol N manufactured by Kao-Atlas and a 20 % aqueous magnesium sulfate, and then mixed with an aqueous gelatin solution to obtain a mono-dispersed cubic emulsion EMP-1 with an average grain size of 0.43 µm, a fluctuation coefficient of 0.08 and a silver chloride content of 99.5 %.

[0090] For EMP-1, chemical ripening was carried out at 55 °C by use of the compounds shown below, SB-1 was added at a time when the optimum sensitometry performance could be obtained and the temperature was lowered to complete chemical ripening to obtain a green-sensitive silver halide emulsion (EmA)

Sodium thiosulfate

      1.5 mg/mole AgX

Chloroauric acid

      1.0 mg/mole AgX

Stabilizer SB-1

    6 x 10^-4 mole/mole AgX

Sensitizing dye SD-1

    4 x 10⁻⁴ mole/mole AgX

[0091] Next, at the stage shown in Table - 1, inorganic sulfur or the sulfide compound according to the present invention was added to prepare Em B - T.

[0092] Em U, V were also prepared in the same manner as Em C, Q except for adding 1.0 mg/mole AgX of chloroauric acid.

[0093] The emulsion prepared and the magenta coupler M - 1 dissolved in dibutyl phthalate were added in 0.4 mole per mole of silver halide, and sodium dodecylbenzenesulfonate added as the coating aid, followed by coating of the mixture on a paper support coated with a polyethylene containing titanium oxide to a coated silver amount of 0.35 g/m² and a gelatin amount of 3.0 g/m². Further, 4.0 g/m² of gelatin was coated as the protective layer thereon.

[0094] The sample obtained was subjected to exposure by use of an EG & G Sensitometer Mark VI (EG & G Electrooptics) for 1 x 10⁻⁵ sec., developed according to the processing steps shown below, and then sensitometry was evaluated by use of Konica Color Densitometer PD-65 (Konica K.K.).

(Evaluation of latent image stability)

[0095] The change (ΔS) in sensitivity and the change in gradation (Δ γ) of density 0.6 - 1.6 when processed after elapse of one hour relative to that processed immediately after exposure as the standard were measured. More excellent stability is shown as both values of ΔS and Δ γ are smaller.

[0096] The results are shown in Table - 1.

[Processing steps]

[0097] 

[Color developing solution]

[0098] 


(made up to total amount of one liter with addition of water, and adjusted to pH=10.10)

[Bleach-fixing solution]

[0099] 


(made up to total amount of one liter, and adjusted to pH=6.2 with potassium carbonate or glacial acetic acid)

[Stabilizing solution]

[0100] 


(made up to one liter with addition of water, and adjusted to pH=7.0 with sulfuric acid or potassium hydroxide)

[0101] The following results can be understood from Table - 1.


*1 mole/AgX mole
*2 Time added of the compounds according to the present invention

Pr-1:

the preparation step of the silver halide grains, provided that it contains the case that the inorganic sulfur or the sulfide compound was added to the reactor before the silver nitrate solution and the halide solution were poured thereto, the case that the inorganic sulfur or the sulfide compound was added to the reactor during pouring the silver nitrate solution and the halide solution thereto, and the case that the inorganic sulfur or the sulfide compound was added to the reactor between from after the silver nitrate solution and the halide solution were poured thereto to before completion of water washing, in any case, the similar results were obtained.

Pr-2:

at the initiation of the chemical sensitization

Pr-3:

at the completion of the chemical sensitization

Pr-4:

from the completion of the chemical sensitization to immediately before coating

Any of Pr-1 to Pr-4 are the addition to the silver halide emulsion.

[0102] 1) By addition of inorganic sulfur, the sulfide compound according to the present invention, latent image stability can be improved.

[0103] 2) Greater improvement effect can be obtained when the timing added of inorganic sulfur and the sulfide compound according to the present invention is within from initiation of chemical ripening to completion of chemical ripening.

[0104] 3) By use of an emulsion subjected to gold sensitization, the effect of the present invention becomes more marked.

Example - 2

[0105] 

[0106] Multi-layer light-sensitive silver halide photographic materials shown in Table - 2 were prepared.




H-1, H-2 were used as the film hardener.






DOP (Dioctyl phthalate)
DNP (Dinonyl phthalate)
DIDP (Diisodecyl phthalate)

[Method for preparing blue-sensitive silver halide emulsion]

[0107] In the same manner as in preparation of EPM-1 except for changing the addition times of (Solution A) and (Solution B) and the addition times of (Solution C) and (Solution D), a mono-dispersed cubic emulsion EMP-2 with an average grain size of 0.85 µm, a fluctuation coefficient of 0.08 and a silver chloride content of 99.5 mole % was obtained. However, the amount of K₂IrCl₆ added was changed to 2 x 10⁻⁷ mole/AgX mole.

[0108] For EMP-2, chemical ripening was carried out by use of the following compounds at 50 °C for 120 minutes to obtain a green-sensitive silver halide emulsion (Em 1).

Sodium thiosulfate

      1.5 mg/mole AgX

Chloroauric acid

      1.0 mg/mole AgX

Stabilizer SB-5

   6 x 10⁻⁴ mole/mole AgX

Sensitizing dye SD-2

   4 x 10^-4 mole/mole AgX

[Method for preparation of red-sensitive silver halide emulsion]

[0109] In the same manner as in preparation of EMP - 1 except for changing the addition times of (Solution A) and (Solution B) and the addition times of (Solution C) and (Solution D), a mono-diseprsed cubic emulsion EMP - 3 with an average grain size of 0.50 µm, a fluctuation coefficient of 0.08 and a silver chloride content of 99.5 mole % was obtained. However, the amount of K₂IrCl₆ was changed to 1 x 10⁻⁶ mole/AgX mole.

[0110] For EMP-3, chemical ripening was carried out by use of the following compounds at 60 °C for 90 minutes, to obtain a red-sensitive silver halide emulsion (Em 2).

Sodium thiosulfate

      1.8 mg/mole AgX

Chloroauric acid

      2.0 mg/mole AgX

Stabilizer SB-5

   6 x 10⁻⁴ mole/mole AgX

Sensitizing dye SD-3

   8 x 10^-4 mole/mole AgX

[0111] Em 3,4 were prepared in the same manner as in preparation of Em 1, and Em 5, 6 as in preparation of Em 2 except for adding inorganic sulfur, the sulfide compound according to the present invention in the amounts shown below.

[0112] As the silver halide emulsion, those shown in Table - 3 were employed to prepare samples 25 - 27, and evaluated similarly as in Example - 1.

[0113] From Table - 3, it can be understood that the object of the present invention can be accomplished also in the case of a light-sensitive multi-layer silver halide material.

Example 3

[0114] In preparation of the sample 25 of Example 2, the blue-sensitive emulsion was replaced with infrared-sensitive emulsions shown below and the dye D - 4 with the equal mole of the dye D - 5, following otherwise the same manner as in Example 2, to prepare light-sensitive silver halide multilayer materials (Samples 26 - 28).

[0115] Similarly, in preparation of the sample 26, the blue-sensitive emulsion and the dye were changed to prepare samples 29 - 31.

(Preparation of infrared-sensitive emulsion)

[0116] For EMP-1 in Example 1, chemical ripening was carried out at 55 °C by use of the compounds shown below to obtain infrared-sensitive emulsion.

Inorganic sulfur

   described below in Table

Sodium thiosulfate

      1.5 mg/mole AgX

Chloroauric acid

      1.0 mg/mole AgX

Stabilizer SB-1

   6 x 10⁻⁴ mole/mole AgX

[0117] When inorganic sulfur was added, it was added at initiation of chemical ripening, and SB-1 was added at the time when the optimum sensitometry performance can be obtained, and chemical ripening stopped by lowering the temperature. Spectral sensitization was performed with addition of an infrared spectral sensitizing dye 3 minutes before addition of SB-1.

[0118] The light-sensitive silver halide photographic material prepared was exposed by a laser printer, and the latent image stability was evaluated in the same manner as in Example 1. The image was prepared by forming a color patch of 10 x 10 mm of yellow, magenta, cyan, and the patch at around the density of 0.8 was measured, and the density compared between the case when developed immediately after exposure and the case when developed one hour later. As the light source of the laser printer, a helium neon laser (wavelength about 633 nm and about 544 nm) and a gallium aluminum arsenic semiconductor laser (wavelength about 780 nm) were employed, and a device was assembled so that the light flux with a diameter of 80 µm at a pitch of 100 µm (the outer peripheral at the place where the light intensity became 1/2 of the maximum value in spatial change of the intensity of the laser light flux, and the distance between the two points where the line passing the point where the light intensity became the maximum and the outer peripheral of the light flux were crossed was made the diameter) could be exposed by scanning at a speed of 1.6 m/sec. At this time, the exposure defined by (diameter of light flux/scanning speed) was found to be 5 x 10⁻⁵ sec.

[0119] The results are shown in Table - 4

[0120] As is apparent from the Table, even when a silver halide emulsion spectrally sensitized to the infrared region was employed and scanning exposure by laser employed, unstability of image output due to deterioration of latent image stability observed in a short time exposure of 5 x 10⁻⁵ sec. has been improved in the image forming method by use of the silver halide emulsion according to the present invention.

Claims

1. An image forming method, which comprises subjecting a light-sensitive silver halide photographic material having at least one photographic constituent layer on a support, said material having at least one of inorganic sulfur or polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond as the constituent of the heterocyclic ring to exposure for a time of 10⁻⁴ sec. or shorter at any stage until said photographic constituent layer of the light-sensitive silver halide photographic material is formed, and then to developing processing.

2. The method of Claim 1 wherein said inorganic sulfur is α-sulfur.

3. The method of Claim 1 wherein the added amount of said inorganic sulfur is within 1 X 10⁻⁵ to 10 mg/1 mole of silver halide.

4. The method of Claim 1 wherein said polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond are the compounds represented by formula (A) or (B):

wherein R₁, R₂ each represent a group which can be substituted on benzene ring or cyclohexane ring, and n represents an integer of 0 to 4. Z₁, Z₂ each represent a group of atoms necessary for formation of a 5- to 8-membered heterocyclic ring containing at least 2 ether bonds or at least one disulfide bond.

5. The method of Claim 1 wherein said polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond are at least one selected from the group consisting of

6. The method of Claim 1 wherein the added amount of said polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond are within 5 X 10⁻⁷ to 5 X 10⁻³ mole/1 mole of silver halide.

7. The method of Claim 1 wherein said silver halide grains contain 80 mole % or more of silver chloride grains.

8. The method of Claim 1 wherein said silver halide grains contain 20 mole % or less of silver bromide grains.

9. The method of Claim 1 wherein said silver halide grains contain 0.5 mole % or less of silver iodide grains.

10. The method of Claim 1 wherein the grain size of said silver halide grains is within 0.2 to 1.6 µm.

11. The method of Claim 1 wherein the grain size distribution of the silver halide grains is mono-dispersed.

12. The method of Claim 1 wherein said photographic material is sensitized by a gold sensitizer.

13. The method of Claim 12 wherein the added amount of said gold sensitizer is within 1 X 10⁻⁸ to 1 X 10⁻¹ mole/1 mole of silver halide.

14. The method of Claim 1 wherein the added timing of said inorganic sulfur or said polysulfide compounds with three or more sulfur atoms linked in the molecular structure or compounds having at least two thioether bonds or at least one disulfide bond is from initiation of chemical ripening to completion of chemical ripening.