Patent Publication Number: US-6210869-B1

Title: Image forming method using heat-developable photosensitive material

Description:
FIELD OF THE INVENTION 
     This invention relates to an image forming method using heat-developable photosensitive material and, more particularly, to an image forming method using heat-developable photosensitive material for scanners or image setters suitable for photomechanical processes. More specifically, this invention relates to an image forming method using heat-developable photosensitive material for photomechanical processes that can be exposed with a high speed, has a high Dmax (maximum density), and can obtain images with less dot shifts through heat development. 
     BACKGROUND OF THE INVENTION 
     A large number of photosensitive materials having a photosensitive layer on a support for forming images upon imagewise exposure have been known. Among them, as a system for rendering preservation of environments and image forming means simplified, a technology for forming images by heat development is exemplified. 
     In recent years, reduction of the amount of waste processing solutions is strongly demanded in the field of photomechanical processes from the standpoint of environmental protection and space savings. To cope with this, techniques are needed in relation to photosensitive heat-developable materials for use in photomechanical processes, which can be effectively exposed by a laser scanner or laser image setter and can form clear black images having high resolution and sharpness. Such heat-developable photosensitive materials can provide to customers a heat development processing system, without use of solution-type processing chemicals, simpler and free from incurring environmental destruction. 
     Methods for forming an image by heat development are described, for example, in U.S. Pat. Nos. 3,152,904 and 3,457,075 and D. Morgan and B. Shely, Imaging Processes and Materials, “Thermally Processed Silver Systems” A, 8th ed., page 2, compiled by Sturge, V. Walworth and A. Shepp, Neblette (1969). The photosensitive material used contains a photo-insensitive silver source (e.g., organic silver salt) capable of reduction, a photocatalyst (e.g., silver halide) in a catalytic activity amount, and a reducing agent for silver, which are usually dispersed in an organic binder matrix. This photosensitive material is stable at room temperature. However, when it is heated at a high temperature (e.g., 80° C. or higher) after the exposure, silver is produced through an oxidation-reduction reaction between the silver source (which functions as an oxidizing agent) capable of reduction and the reducing agent. The oxidation-reduction reaction is accelerated by the catalytic action of a latent image generated upon exposure. The silver produced by the reaction of the silver salt capable of reduction in the exposure region provides a black image and this presents a contrast to the non-exposure region. Thus, an image is formed. 
     Meanwhile, with respect to light exposure of those heat-developable photosensitive materials, there are exposure ways done by an exposing apparatus in aim at improving productivity, e.g., high illumination rapid exposure of 10 to 7 seconds or less. However, the heat-developable photosensitive materials generally raises a problem that the concentration is low in such the high illumination rapid exposure. To make an improvement, a method, a so-called multiple exposing method, is used to expose the heat-developable photosensitive materials as disclosed in JP-W-A-10-500229, in which laser beam or the like are overlapped to make exposure. This method, though it is a technique to improve the sensitivity and contrast by overlapping beam spots more, has a problem that the exposure actually takes more time. 
     The heat-developable photosensitive materials have been known previously, but in most of those, the photosensitive layer is formed by coating a coating liquid having a solvent of an organic solvent such as toluene, methyl ethyl ketone (MEK), methanol, and the like. Use of such organic solvents as a solvent not only adversely affects human bodies during manufacturing processes but also is disadvantageous in term of costs due to recycling the solvents and others. 
     To cope with this, a method has been considered in which a photosensitive layer (hereinafter referred also to as “aqueous photosensitive layer”) is formed using a coating liquid of a water solvent not having the above problem. For example, JP-A-49-52,626 and 53-116,144, and the like set forth an example that gelatin is used as a binder. Also, JP-A-50-151,138 sets forth an example that a poly vinyl alcohol is used as a binder. 
     In JP-A-60-28,737, an example that a gelatin and a poly vinyl alcohol are used together is described. In addition, as another example other than the above examples, JP-A-58-28,737 sets forth an example of a photosensitive layer that a water-soluble poly vinyl acetal is used as a binder. 
     Such a binder surely allows to form the photosensitive layer in use of a coating liquid with a water solvent, thereby making such use advantageous in terms of environments and costs. 
     However, if the polymer such as gelatin, poly vinyl alcohol, water-soluble poly vinyl acetal, and so on is used as the binder, the binder has a bad solubility with an organic silver salt, thereby not only rendering coatings unavailable with a surface having a practically durable quality, but also rendering a silver tone at the developed portion brown or yellow which is so deviated from black, originally favored color, or obtaining only products having considerably diminished values such that the blackened concentration at a light exposed section is low while the concentration at an unexposed portion is high. 
     European Patent No. 762,196, and JP-A-9-90,550 disclose that photosensitive silver halide particles used for the heat-developable photosensitive materials contain VII-group or VIII-group metal ions or metal complex ions and that high contrast photographic characteristics can be obtained by containing hydrazine derivatives in the photosensitive materials. However, if the binder used in the coating liquid of the above water solvent and a nucleation agent such as hydrazine are concurrently used, a high contrast image can be obtained, but at the same time there raise problems such that fog may likely occur, and that dot shifts during the heat development become large. 
     Therefore, a technology is desired providing an image forming method using heat-developable photosensitive material capable of being exposed with high speed and obtaining images with low fog, high Dmax (maximum density), and less dot shifts during the heat development, having advantages in terms of environments and costs. 
     Accordingly, the first object to be accomplished by the invention is to provide an image forming method using heat-developable photosensitive material capable of being exposed with high speed and obtaining images with low fog, high Dmax (maximum density), and less dot shifts during the heat development, particularly suitable for photomechanical processes as well as for scanners or image setters. 
     The second object of the invention to be solved is to provide an image forming method using a heat-developable photosensitive material capable of coating with water with advantages in terms of environments and costs. 
     SUMMARY OF THE INVENTION 
     The objects are accomplished by the means below. That is: 
     1) An image forming method using heat-developable photosensitive material comprising, for forming images, the steps of exposing images imagewisely in overlapping light beam to a heat-developable photosensitive material including on a support a non-photosensitive silver salt, a photosensitive silver halide, and a binder and of developing the images with heat, wherein an overlap coefficient which is ratio of a full width at half maximum (FWHM) of a beam intensity in a beam spot used for imagewise exposure to a subscanning pitch width is 0.2 or higher and 0.5 or lower, wherein an exposing time is of a high illumination rapid exposure less than 10 −7  second, and wherein the γ of the heat-developable photosensitive material after the step of developing the images with heat (wherein the γ is the gradient of a straight line connecting the density points of 0.2 and 2.5 where the logarithm of the exposing amount is abscissa) is set as 5≦γ≦15. 
     2) The image forming method using heat-developable photosensitive material of 1), wherein at least 50% by weight of the binder of an image forming layer containing the photosensitive silver halide of the heat-developable photosensitive material is a polymer latex having a glass transition temperature of −30° C. or higher and 40° C. or lower, and wherein a nucleation agent is contained in the image forming layer or an adjacent layer adjacent thereto. 
     3) The image forming method using heat-developable photosensitive material of 1), wherein at least 50% by weight of the binder of an image forming layer containing the photosensitive silver halide of the heat-developable photosensitive material is a polymer latex having a glass transition temperature of −30° C. or higher and 40° C. or lower, wherein at least 50 % by weight of the binder of a protection layer formed on a side having the image forming layer is a polymer latex having a glass transition temperature of 25° C. or higher and 70° C. or lower, and wherein a nucleation agent is contained in the image forming layer or an adjacent layer adjacent thereto. 
     4) The image forming method using heat developable photosensitive material of 2), wherein the nucleation agent is at least one compound selected from a substituted alkene derivative as represented by formula (1), a substituted isoxazole derivative as represented by formula (2), and a specific acetal compound as represented by formula (3),                    
     In the formula (1), R 1 , R 2  and R 3  each independently represents a hydrogen atom or a substituent, Z represents an electron withdrawing group or a silyl group, and R 1  and Z, R 2  and R 3 , R 1  and R 2 , or R 3  and Z may be combined with each other to form a ring structure; in the formula (2), R 4  represents a substituent; and in the formula (3), X and Y each independently represents a hydrogen atom or a substituent, A and B each independently represents an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic oxy group, a heterocyclic thio group or a heterocyclic amino group, and X and Y. or A and B may be combined with each other to form a ring structure. 
     5) The image forming method using heat developable photosensitive material of 2), wherein the nucleation agent is a hydrazine compound. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view showing a structural example of a heat developing machine usable for implementing the method according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An exposing apparatus used for imagewise exposure of the invention can be any apparatus capable of making exposure of 10 to 7 seconds or less, and in general, a preferable exposing apparatus uses as a light source an LD (Laser Diode), an LED (Light Emitting Diode). Particularly, the LD is preferable in terms of high output and high resolution. Those light sources can be any thing capable of generating light having an electromagnetic wave spectrum of a targeted wavelength range. For example, as LDs, a dye laser, gas laser, solid laser, semiconductor laser or the like can be used. 
     Exposure of the invention means that the light beams of a light source are overlapped to make an exposure, and overlapping here indicates the pitch width of the subscanning is smaller than a beam diameter. Overlap can be expressed in a quantitative manner with FWHM divided by subscanning pitch width (overlap coefficient) where the beam diameter is represented with a full width at half maximum (FWHM) of a beam intensity. In this invention, the overlap coefficient is 0.2 or higher and 0.5 or lower, and lower value is preferable from a standpoint of high productivity. 
     The scanning method of a light source of the exposing apparatus used in this invention is not limited, and any of a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a plane scanning method, and the like can be used. The channel of a light source can be either a single channel or multiple channels, and in the case of the cylindrical outer surface method, the multiple channels can be used preferably. 
     The heat-developable photosensitive material of the present invention has a low haze at the exposure and is liable to incur generation of interference fringes. For preventing the generation of interference fringes, a technique of entering a laser ray obliquely with respect to the image-recording material disclosed in JP-A-5-113548 and a method of using a multimode laser disclosed in International Patent Publication WO95/31754 are known and these techniques are preferably used. 
     While the heat developing process of an image forming method of the present invention may be developed by any method, development is usually performed by elevating the temperature of the photosensitive material after the imagewise exposure. As a favorable embodiment of a used heat developing machine, heat developing machines set forth in JP-A-5-56,499, Japanese Patent No. 684453, JP-A-9-292,695, 9-297,385, and International Patent WO No. 95/30934 as types in which the heat-developable photosensitive material is in contact with a heat source such as a heat roller and a heat drum, heat developing machines set forth in JP-A-7-13,294, International Patent Nos. WO 97/28489, WO 97/28488, and WO 97/28487 as non-contact types are exemplified. A more preferable embodiment is a non-contact type heat developing machine. A preferable development temperature is from 80 to 250° C., more preferably from 100 to 140° C. The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds. 
     As a method for preventing processing uneveness due to size deviations during heat development of the heat-developable photosensitive material of the invention, a method for forming images (so called multistage heating method) by heat development at a temperature of 110° C. or higher and 140° C. or less after so heating five seconds or longer at a temperature of 80° C. or higher and less than 115° C. as not to create images is effective. 
     The organic silver salt which can be used in the present invention is a silver salt which is relatively stable against light but forms a silver image when it is heated at 80° C. or higher in the presence of an exposed photocatalyst (e.g., a latent image of photosensitive silver halide) and a reducing agent. The organic silver salt may be any organic substance containing a source capable of reducing the silver ion. A silver salt of an organic acid, particularly a silver salt of a long chained aliphatic carboxylic acid (having from 10 to 30, preferably from 15 to 28 carbon atoms) is preferred. A complex of an organic or inorganic silver salt, of which ligand has a complex stability constant of from 4.0 to 10.0, is also preferred. The silver-supplying substance may constitute preferably from about 5 to 70% by weight of the image-forming layer. The preferred organic silver salt includes a silver salt of an organic compound having a carboxyl group. Examples thereof include an aliphatic carboxylic acid silver salt and an aromatic carboxylic acid silver salt. However, the present invention is by no means limited thereto. Preferred examples of the aliphatic carboxylic acid silver salt include silver behenate, silver arachidinate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate, silver camphorate and a mixture thereof. 
     In this invention, it is preferable to use, among the organic acid silvers or mixtures of the organic acid silvers exemplified above, the organic acid silver having a silver behenate containing rate of 85 mol % or higher, more preferably 95 mol % or higher. The silver behenate containing rate indicates a mole percentage of the silver behenate to the organic acid silver to be used. As organic acid silver other than the silver behenate contained in the organic acid silver used in this invention, the above exemplified materials can be used preferably. 
     The organic acid silvers preferably used in this invention are prepared by reaction of an alkali metal salt (sodium salt, potassium salt, lithium salt, and the like can exemplified) solution or suspension of the organic acid silver as described above with silver nitrate. The organic acid alkali metal salt of the present invention can be obtained from alkali treatments of the above organic acid. The organic acid silver of the invention can be done in either a rotary or continuous manner in an arbitrary suitable container. Stirring in the reaction container can be done by any stirring method depending on the characteristics demanded from the particles. As a preparing method for organic acid silver, any of methods can be preferably used in which a silver nitrate solution is slowly or rapidly added in a reaction container containing an organic acid alkali metal salt solution or suspension, in which a previously prepared organic acid alkali metal salt solution or suspension is slowly or rapidly added in a reaction container containing a silver nitrate solution, and in which a previously prepared silver nitrate solution and an organic acid alkali metal salt solution or suspension are added at the same time in a reaction container. 
     The silver nitrate solution and the organic acid alkali metal salt solution or suspension can be used with any concentration to control the particle size of the prepared organic acid silver, and can be added with any addition rate. As a method for adding the silver nitrate solution and the organic acid alkali metal salt solution or suspension, a method for adding at a constant addition rate, a method for acceleratingly or deceleratingly adding according to an arbitrary time function can be used. The solution and the like can be added to the reaction liquid at the liquid surface or in the liquid. In the case of the method in which the previously prepared silver nitrate solution and the organic acid alkali metal salt solution or suspension are added at the same time in a reaction container, though any of the silver nitrate solution and the organic acid alkali metal salt solution or suspension can be added first, it is preferable to add the silver nitrate solution first. As a preceding degree, an amount of 0 to 50% of the total amount is used preferably, and more preferably, it is 0 to 25%. A method in which addition is made while the pH and the silver potential of a reaction liquid is controlled during reaction as described in JP-A-9-127,643. 
     The silver nitrate solution and the organic acid alkali metal salt solution or suspension to be added can control the pH according to the characteristics demanded from the particles. To adjust the pH, an arbitrary acid or alkali can be added. According to the characteristics demanded from the particles, for example, for controlling the particle size of the prepared organic acid silver, the temperature in the reaction container can be set arbitrarily, but also the silver nitrate solution and the organic acid alkali metal salt solution or suspension can be adjusted at an arbitrary temperature. To make sure the fluidity of the organic acid alkali metal salt solution or suspension, it is preferable to keep at 50° C. or higher with heating. 
     The organic acid silver used in this invention is preferably prepared under existence of a tertiary alcohol. As a tertiary alcohol, it is preferable to use an alcohol having a total carbon number of 15 or less, more preferably 10 or less. As an example of a preferable tertiary alcohol, tert-butanol and the like are exemplified, but this invention is not limited to those. 
     Although the timing of addition of the tertiary alcohol used in this invention can be any timing during the preparation of the organic acid silver, it is preferable to solve and use the organic acid alkali metal salt upon addition of the alcohol during the preparation of the organic acid alkali metal salt. The use amount of the tertiary alcohol of the invention can be any amount in range of 0.01 to 10 by weight ratio to H 2 O as a solvent during the preparation of the organic acid silver, but the range of 0.03 to 1 is preferable. 
     As a shape of the organic silver salt usable in this invention, there are no special limitations thereof, but a needle crystal having the minor axis and the major axis. In this invention, it is preferable that the minor axis is of 0.01 micron or more and 0.20 micron or less while the major axis is of 0.10 micron or more and 5.0 microns or less, and more preferably, it is that the minor axis is of 0.01 micron or more and 0.15 micron or less while the major axis is of 0.10 micron or more and 4.0 microns or less. The size profile of the particles of the organic silver salt is preferably a single dispersion. The single dispersion is defined that the percentage of the standard divinations of the lengths of the minor and major axes divided by the minor and major axes, respectively, is preferably, 100% or less, more preferably, 80% or less, and further preferably, 50% or less. As a measuring method of shapes of the organic silver salt, it can be sought by an image made with a transmission type electron microscope of an organic silver salt dispersion. As another method for measuring the single dispersion, there is a method for seeking the standard deviation of the volume weighted mean diameter of the organic silver salt, and the percentage (deviation coefficient) of a value divided by the volume weighted mean diameter is preferably, 100% or less, more preferably, 80% or less, and further preferably, 50% or less. As a measuring method, a laser beam is radiated to the organic silver salt dispersed in the liquid, and it can be sought from obtained particle sizes (volume weighted mean diameter) through a self-correlation function with respect to time change of fluctuation of the scattered light of the laser beam. 
     The organic silver salt usable in this invention is preferably subject to desalting. There is no special limitation to methods for desalting, and known methods can be used. It is preferable to use known filtering methods such as centrifugal filtering, absorbing filtering, ultrafiltration, frock forming washing by cohesion method, and so on. 
     In this invention, for obtaining a solid dispersed material of organic silver salt having a smaller particle size with high SIN ratio and without cohesion, a dispersion method is preferably used in which a pressure is decreased after a water dispersion liquid including an organic silver salt serving as image forming media and substantially excluding photosensitive silver salt is converted into a high speed flow. 
     A photosensitive image forming medium coating liquid is manufactured in mixing the photosensitive silver salt solution after such a process. If a heat-developable photosensitive material is produced using such a coating liquid, a heat-developable photosensitive material can be obtained with low haze, low fog and high sensitivity. To the contrary, if the flow is converted to high pressure, high speed flow, and if the photosensitive silver coexists during the dispersion, the fog increases and the sensitivity is lowered so much. If an organic solvent, instead of water, is used for a dispersing medium, the haze becomes so high, and the fog increases, while the sensitivity is likely lowered. On the other hand, if a conversion method in which a part of the organic silver salt in the dispersing liquid is converted into a photosensitive silver salt is used, the sensitivity is reduced. 
     The water dispersing liquid dispersed upon conversion to high pressure and high speed flow substantially excludes a photosensitive sliver salt, and the moisture amount is 0.1 mol % or less with respect to the non-photosensitive type organic silver salt, and the photosensitive silver salt is not positively added. 
     In this invention, a solid dispersion apparatus and its technology used for implementing the above dispersing methods are described in detail in, e.g., “Bunsankei Rheology to Bunsankagijyutu (Disperse System Rheology and Dispersing Technology)”, Toshio Kajiuchi, Hiroki Usui, 1991 Shinzannsya Shuppan (K.K.) p357 to p403, and “Kagaku Kogyou no Sinpo, Dai 24 shyu (Progress of Chemical Engineering, Vol. 24), Shyadan Houjinn, Kagakukougyou-kai Tokai shibu, 1990, Maki Shoten, p184 to p185. The dispersing method in this invention is a method in which, after a water dispersion material at least including an organic silver salt is sent in a pipe upon pressurized by means of, e.g., a high pressure pump, the material is made to pass through fine slits formed in the pipe, and subsequently the dispersion liquid is rapidly subject to a reduced pressure thereby forming fine dispersions. 
     With respect to a high pressure homogenizer relating to this invention, it is generally thought that dispersion to fine particles occurs by, e.g., “shearing force” occurring at a time when the dispersoid passes through narrow intervals with high pressure and high speed, and “cavitation force” occurring when the dispersoid is released from the high pressure to the normal pressure. A Gorlin homogenizer can be exemplified as a dispersing apparatus of this type, and in this apparatus, a liquid to be dispersed under a high pressure is converted at narrow channels on a cylindrical surface to a high speed fluid, and collides to surrounding walls with that acceleration, thereby forming emulsion and dispersion by the impacting force. The pressure used is generally in a range of 100 to 600 kg /cm 2 , and the fluid rate is in a range of several meters to 30 meters per second. To increase the dispersing effect, some are devised to have the high speed portion in a serriform to increase the number of collisions. Meanwhile, recently developed apparatuses are capable of dispersing with further higher pressure and higher flow velocity, and as a representative example, such as Microfluidizer (Microfluidics International Corporation), Nanomizer (Tokusyu Kika Kougyou (K.K.) can be exemplified. 
     As a dispersing apparatus suitable for this invention, Microfluidizer (Microfluidics International Corporation made),M-110S-EH [G10Z with interaction chamber], M-110Y [H10Z with interaction chamber], M-140K [G10Z with interaction chamber], HC-5000 (L30Z or H230Z with interaction chamber], HC-8000 [E230Z or L30Z with interaction chamber], and the like are exemplified. 
     A most suitable organic silver salt dispersed material for this invention can be obtained, using those apparatuses, by creating rapid reduction of pressure in the dispersion liquid by a method such that the pressure in the pipe is rapidly backed to the atmospheric pressure after applying a desired pressure to a water dispersion liquid including at least an organic silver salt by passing the liquid through fine slits formed in the pipe after the liquid is sent to the pipe with pressure from a high pressure pump or the like. 
     Before the dispersion manipulation, it is preferable to disperse the raw material liquid previously. As a means for pre-dispersion, known dispersing means (such as a high speed mixer, homogenizer, high impact mill, banbury mixer, homo mixer, kneeder, bowl mill, vibration bowl mill, planet bowl mill, atwriter, sand mill, beads mill, colloid mill, jet mill, roller mill, tron mill, high speed stone mill) can be used. The liquid can be made with fine particles, in a way other than subjecting to the mechanical dispersion, by changing the pH under existence of dispersion promoters after rough dispersion is made in the solvent by a pH control. As a solvent for the rough dispersion, an organic solvent can be used, and normally, the organic solvent is removed after making the fluid with fine particles. 
     In the dispersion of the organic silver salt in the invention, the dispersion can be made with desired particle sizes by adjustments of the fluid speed, the differential pressures during pressure reduction, and the number of processings. From a standpoint to the photographic characteristics and the particle sizes, a preferable fluid speed is of 200 m/sec to 600 m/sec, and the differential pressure during the reduction of the pressure is preferably in range of 900 to 3,000 kg /CM 2 . More preferably, the fluid speed is of 300 m/sec to 600 m/sec, and the differential pressure during the reduction of the pressure is preferably in range of 1,500 to 3,000 kg/cm 2  The processing number of dispersions can be selected according the necessity, and in a normal case, the processing number of one to ten times is selected, and from a standpoint of productivity, the processing number of one to three times is selected. Making the water dispersion liquid at a high temperature under a high pressure is not favorable in terms of dispersion property and photographic characteristics, and if the temperature is high as to exceed 90° C., the particle size may be larger, and fog may increase. Accordingly, in this invention, a cooling process may be contained in either or both of a process before conversion to the high speed flow and a process after the pressure is reduce, and it is preferable to keep the temperature of such a water dispersion in a range of 5 to 90° C. by such a cooling process, more preferably, in range of 5 to 80° C., and further 5 to 60° C. Furthermore, it is effective to set the cooling process as described above for high pressure dispersion in a range of 1500 to 3000 kg /cm 2 . The cooling apparatus can be selected from a double pipe, one using a static mixer for a double pipe, a multiple pipe type heat converter, a jig-sag pipe type heat converter, and the like. To increase the efficiency of the heat conversion, diameter, thickness, and material of the pipe are selected to be suitable in consideration of the used pressure. The coolant used in the cooling apparatus can be, in consideration of the heat conversion amount, a well water of 20° C. or a cool water of 5 to 10° C. processed in a refrigerator, or a coolant of ethylene glycol and water of −30° C. when necessary. 
     In a dispersion manipulation of the invention, it is preferable to disperse the organic silver salt under existence of a dispersant (dispersion promoter) soluble in an aqueous solvent. As a dispersion promoter, for example, synthetic anion polymers such as polyacrylic acid, acrylic acid copolymer, maleic acid monoester copolymer, and acryromethyl propanesulfonic acid copolymer, semi-synthetic anion polymers such as carboxylmethyl starch, and carboxylmethyl cellulose, anionic polymers such as alginic acid, and pectic acid, a compound as set forth in JP-A-7-350,753, known polymers such as anionic, nonionic, or cationic surfactants, and polyvinylalcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxymethylcellulose, and hydroxypropylmethylcellulose, and a polymer compound existing naturally such as gelatin or the like can be used, and furthermore, polyvinylalcohol groups, and water-soluble cellulose derivatives can be used more preferably. 
     The dispersion promoter is made ordinarily by being mixed with powders of the organic silver salt or a wet cake state organic silver salt to be sent to a dispersing machine as a slurry, but can be mixed with the powers of the organic silver salt or a wet cake state organic silver salt upon processing of a thermal treatment or solvent treatment where mixed with the organic silver salt in advance. It can be subject to a pH control with a proper pH adjusting agent before or after or during dispersion. 
     In addition to the mechanical dispersion, the dispersion promoter can be dispersed roughly upon the pH control, and then, fine particles can be formed upon changing the pH under existence of the dispersion promoter. At that time, as a solvent used for the rough dispersion, an organic solvent can be used, and ordinarily, such an organic solvent is removed after maaking fine particles. 
     The prepared dispersed materials may be preserved while being stirred to suppress precipitation of fine particles during preservation or preserved at a high viscosity state (for example, gelatin is used in a jelly state) by means of hydrophilic colloids. An antiseptics may be added to prevent bacteria or the like from prospering. 
     The particle size (volume weighted mean diameter) of the solid fine particle dispersing material of the organic silver salt of the invention can be sought from, e.g., obtained particle sizes (volume weighted mean diameter) through a self-correlation function with respect to time change of fluctuation of a scattered light where a laser beam is radiated to the solid fine particle dispersing material dispersed in the liquid. The solid fine particle dispersing material desirably has a mean particle size of 0.05 micron or higher and 10.0 microns or lower, more preferably, a mean particle size of 0.1 micron or higher and 5.0 microns or lower, and further preferably, a mean particle size of 0.1 micron or higher and 2.0 microns or lower. 
     The particle size profile of the organic silver salt is preferable in a single dispersion. More specifically, the percentage (deviation coefficient) of a value that the standard deviation of the volume weighted mean diameter is divided by the volume weighted mean diameter is preferably, 80% or less, more preferably, 50% or less, and further preferably, 30% or less. As a measuring method of shapes of the organic silver salt, it can be sought by an image made with a transmission type electron microscope of an organic silver salt dispersion. 
     The solid fine particle dispersing material of the organic silver salt used in the invention includes at least the organic silver salt and water. There is no special limitation to the rate of the organic silver salt and the water, but the rate of the organic silver salt to the entirety is preferably 5 to 50% by weight, and more preferably, 10 to 30% by weight. It is preferable to use the dispersion promoter as described above. It is preferable to use it in a minimum amount in a range suitable for minimizing the particle size, and it is preferable to set it 1 to 30% by weight and particularly, in a range of 3 to 15% by weight. 
     With this invention, the photosensitive material can be manufactured by mixing the organic silver salt water dispersing liquid and the photosensitive sliver salt water dispersing liquid with each other. The mixing rate of the organic silver salt and the photosensitive silver can be selected depending on the purpose, and the rate of the organic silver salt to the photosensitive silver salt is preferably in a range of 1 to 30 mol %, more preferably, 3 to 20 mol %, and further preferably, 5 to 15 mob %. To mix two or more types of the organic silver salt water dispersing liquids and two or more types of the photosensitive sliver salt water dispersing liquids with each other is a suitable method used for adjusting the photographic property. 
     The organic silver salt of the invention can be used in a desired amount, and the suitable silver amount is 0.1 to 5 g/m 2 , more preferably, 1 to 3 g/m 2 . 
     In this invention, a metal ion or ions selected from Ca, Mg, Zn, and Ag can be preferably added to the non-photosensitive organic silver salt. The addition of the metal ion or ions selected from Ca, Mg, Zn, and Ag to the non-photosensitive organic silver salt is preferably made in a form of not a halide, but a watersoluble metal salt, more specifically, in a form of a nitrate, a sulfite, or the like. Addition of halide is not preferable because image preservation property, in other words, printout property of the photosensitive material is made inferior due to light (e.g., room light or sun light) after the processing. Therefore, in this invention, not the above halide but the addition in the form of the water-soluble metal salt is preferably used. 
     As an addition timing of the metal ion or ions selected from Ca, Mg, Zn, and Ag preferably used in this invention, any timing can be used such as after particle forming of the non-photosensitive organic silver salt, right after particle forming, before dispersion, after dispersion, and before or after preparation of the coating liquid, as far as it is right before the coating or earlier, and more preferably, it is after dispersion, or before or after preparation of the coating liquid. 
     As an addition amount of the metal ion or ions selected from Ca, Mg, Zn, and Ag in this invention, it is of 10 −3  to 10 −1  mol per one mol of the non-photosensitive organic silver salt, and more preferably, 5×10 −3  to 5×10 −2  mol. 
     The photosensitive silver halide is not limited as a halogen composition, and can be made of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, and silver iodochlorobromide. The profile of the halogen composition in the particle can be uniform, changed stepwise in the halogen composition, or change continuously. Silver halide particles having a core or shell structure can be used preferably. As a structure, a structure of two to five layers is preferably used, and more preferably, core or shell particles of a structure of two to four layers is used. A technology in which silver bromide is located on surfaces of the particles of silver chloride or silver chlorobromide can be used preferably. 
     The method of forming photosensitive silver halide used for the present invention is well known in the art and, for example, the methods described in  Research Disclosure,  No. 17029 (June, 1978) and U.S. Pat. No. 3,700,458 may be used. Specifically, a method comprising converting a part of silver in the produced organic silver salt to photosensitive silver halide by adding a halogen-containing compound to the organic silver salt, or a method comprising adding a silver-supplying compound and a halogen-supplying compound to gelatin or other polymer solution to thereby prepare photosensitive silver halide and mixing the silver halide with an organic silver salt may be used for the present invention. The photosensitive silver halide particle preferably has a small particle size so as to prevent high white turbidity after the formation of an image. Specifically, the particle size is preferably 0.20 μm or less, more preferably from 0.01 to 0.15 μm, still more preferably from 0.02 to 0.12 μm. The term “particle size” as used herein means the length of an ridge of the silver halide particle in the case where the silver halide particle is a regular crystal such as cubic or octahedral particle; the diameter of a circle image having the same area as the projected area of the main surface plane in the case where the silver halide particle is a tabular silver halide particle; or the diameter of a sphere having the same volume as the silver halide particle in the case of other irregular crystals such as spherical or bar particle. 
     Examples of the shape of the silver halide particle include cubic form, octahedral form, tabular form, spherical form, stick form and bebble form, and among these, cubic particle and tabular particle are preferred in the present invention. When a tabular silver halide particle is used, the average aspect ratio is preferably from 100:1 to 2:1, more preferably from 50:1 to 3:1. A silver halide particle having rounded corners is also preferably used. The face index (Miller indices) of the outer surface plane of a photosensitive silver halide particle is not particularly limited; however, it is preferred that [100] faces capable of giving a high spectral sensitization efficiency upon adsorption of the spectral sensitizing dye occupy a high ratio. The ratio is preferably 50% or more, more preferably 65% or more, still more preferably 80% or more. The ratio of [100] faces according to the Miller indices can be determined by the method described in T. Tani,  J. Imaging Sci.,  29, 165 (1985) using the adsorption dependency of [111] face and [100] face upon adsorption of the sensitizing dye. 
     The photosensitive silver halide particle for use in the present invention contains a metal or metal complex of Group VII or VIII in the Periodic Table. The center metal of the metal or metal complex of Group VII or VIII of the Periodic Table is preferably rhodium, rhenium, ruthenium, osnium or iridium. One kind of metal complex may be used or two or more kinds of complexes of the same metal or different metals may also be used in combination. The metal complex content is preferably from 1×10 −9  to 1×10 −2  mol, more preferably from 1×10 −8  to 1×10 −4  mol. per mol of silver. With respect to the specific structure of the metal complex, the metal complexes having the structures described in JP-A-7-225,449 may be used. 
     As the rhodium compound for use in the present invention, a water-soluble rhodium compound may be used. Examples thereof include a rhodium(III) halogenide compounds and rhodium complex salts having a halogen, an amine or an oxalate as a ligand, such as hexachlororhodium(III) complex salt, pentachloroaquorhodium(III) complex salt, tetrachlorodiaquorhodium(III) complex salt, hexabromorhodium(III) complex salt, hexaamminerhodium(III) complex salt and trioxalatorhodium(III) complex salt. The rhodium compound is used after dissolving it in water or an appropriate solvent and a method commonly used for stabilizing the rhodium compound solution, that is, a method comprising adding an aqueous solution of hydrogen halogenide (e.g., hydrochloric acid, bromic acid, fluoric acid) or halogenated alkali (e.g., KCl, NaCl, KBr, NaBr) may be used. In place of using a water-soluble rhodium, separate silver halide particles previously doped with rhodium may be added and dissolved at the time of preparation of silver halide. 
     The amount of the rhodium compound added is preferably from 1×10 −8  to 5×10 −6  mol. more preferably from 5×10 −8  to 1×10 −6  molt per mol of silver halide. 
     The rhodium compound may be appropriately added at the time of production of silver halide emulsion particles or at respective stages before coating of the emulsion. However, the rhodium compound is preferably added at the time of formation of the emulsion and integrated into the silver halide particle. 
     The rhenium, ruthenium or osmium for use in the present invention is added in the form of a water-soluble complex salt described in JP-A-63-2042, JP-A-1-285941, JP-A-2-20852 and JP-A-2-20855. A preferred example thereof is a six-coordinate complex salt represented by the following formula: 
     
       
         [ML 6 ] n−   
       
     
     wherein M represents Ru, Re or Os, L represents a ligand, and n represents 0, 1, 2, 3 or 4. In this case, the counter ion plays no important role and an ammonium or alkali metal ion is used. 
     Preferred examples of the ligand include a halide ligand, a cyanide ligand, a cyan oxide ligand, a nitrosyl ligand and a thionitrosyl ligand. Specific examples of the complex for use in the present invention are shown below, but the present invention is by no means limited thereto. 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 [ReCl 6 ] 3−   
                 [ReBr 6 ] 3−   
                 [ReCl 5 (NO)] 2−   
               
               
                   
                 [Re(NS)Br 5 ] 2−   
                 [Re(NO) (CN) 5 ] 2−   
                 [Re(O) 2 (CN) 4 ] 3−   
               
               
                   
                 [RuCl 6 ] 3−   
                 [RuCl 4 (H 2 O) 2 ] −   
                 [RuCl 5 (H 2 O) ] 2−   
               
               
                   
                 [RuCl 5 (NO)] 2−   
                 [RuBr 5 (NS)] 2−   
               
               
                   
                 [Ru(CO) 3 Cl 3 ] 2−   
                 [Ru(CO)Cl 5 ] 2−   
                 [Ru(CO)Br 5 ] 2−   
               
               
                   
                 [OsCl 6 ] 3−   
                 [OsCl 5 (NO)] 2−   
                 [Os(NO) (CN) 5 ] 2−   
               
               
                   
                 [Os(NS)Br 5 ] 2−   
                 [Os(O) 2 (CN) 4 ] 4−   
               
               
                   
                   
               
            
           
         
       
     
     The addition amount of these compound is preferably from 1×10 −9  to 1×10 −5  mol. more preferably from 1×10 −8  to 1×10 −6  mol. per mol of silver halide. 
     These compounds may be added appropriately at the time of preparation of silver halide emulsion particles or at respective stages before coating of the emulsion, but the compounds are preferably added at the time of formation of the emulsion and integrated into a silver halide particle. 
     For adding the compound during the particle formation of silver halide and integrating it into a silver halide particle, a method where a metal complex powder or an aqueous solution having dissolved therein the metal complex together with NaCl or KCl is added to a water-soluble salt or water-soluble halide solution during the particle formation, a method where the compound is added as the third solution at the time of simultaneously mixing a silver salt and a halide solution to prepare silver halide particles by the triple jet method, or a method where a necessary amount of an aqueous metal complex solution is poured into a reaction vessel during the particle formation, may be used. Among these, preferred is a method comprising adding a metal complex powder or an aqueous solution having dissolved therein the metal complex together with NaCl or KCl to a water-soluble halide solution. 
     In order to add the compound to the particle surface, a necessary amount of an aqueous metal complex solution may be charged into a reaction vessel immediately after the particle formation, during or after completion of the physical ripening, or at the time of chemical ripening. 
     As the iridium compound for use in the present invention, various compounds may be used, and examples thereof include hexachloroiridium, hexammineiridium, trioxalatoiridium, hexacyanoiridium and pentachloronitrosyliridium. The iridium compound is used after dissolving it in water or an appropriate solvent, and a method commonly used for stabilizing the iridium compound solution, more specifically, a method comprising adding an aqueous solution of hydrogen halogenide (e.g., hydrochloric acid, bromic acid, fluoric acid) or halogenated alkali (e.g., KCl, NaCl, KBr, NaBr) may be used. In place of using a water-soluble iridium, separate silver halide particles previously doped with iridium may be added and dissolved at the time of preparation of silver halide. 
     The silver halide particle for use in the present invention may further contain a metal atom such as cobalt, iron, nickel, chromium, palladium, platinum, gold, thallium, copper and lead. In the case of cobalt, iron, chromium or ruthenium compound, a hexacyano metal complex is preferably used. Specific examples thereof include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion, hexacyanochromate ion and hexacyanoruthenate ion. However, the present invention is by no means limited thereto. The phase of the silver halide, in which the metal complex is contained, is not particularly limited, and the phase may be uniform or the metal complex may be contained in a higher concentration in the core part or in the shell part. 
     The above-described metal is used preferably in an amount of from 1×10 −9  to 1×10 −4 mol per mol of silver halide. The metal may be converted into a metal salt in the form of a simple salt, a composite salt or a complex salt and added at the time of preparation of particles. 
     The photosensitive silver halide particle may be desalted by water washing according to a method known in the art, such as noodle washing and flocculation, but the particle may not be desalted in the present invention. 
     As a gold sensitizer used when the silver halide emulsion of the invention is subject to gold sensitization, gold compound used ordinarily as a gold sensitizer having an oxidation number of monovalent or trivalent can be used. As representative examples, chroloaurate , potassium chroloaurate, aurictrichloride, potassium aurictiocyanate, potassium iodoaurate, tetracyanoauric acid, ammonium aurotiocyanate, pyrdyltrichlorogold, and the like are exemplified. 
     The addition amount of the gold sensitizer may vary depending on each condition, and as a standard, it is 10 −7  mol or higher and 10 −3  mol or lower per one mol of the silver halide, and more preferably, it is 10 −6  mol or higher and 5×10 −4  mol or lower. 
     It is preferable to use together the gold sensitization and other chemical sensitizations for the silver halide emulsion of the invention. As other chemical sensitizations, the chemical sensitization may be performed using a known method such as sulfur sensitization, selenium sensitization, tellurium sensitization or noble metal sensitization. These sensitization method may be used alone or in any combination. When these sensitization methods are used as a combination, a combination of sulfur sensitization and gold sensitization, a combination of sulfur sensitization, selenium sensitization and gold sensitization, a combination of sulfur sensitization, tellurium sensitization and gold sensitization, and a combination of sulfur sensitization, selenium sensitization, tellurium sensitization and gold sensitization, for example, are preferred. 
     The sulfur sensitization preferably used in the present invention is usually performed by adding a sulfur sensitizer and stirring the emulsion at a high temperature of 40° C. or higher for a predetermined time. The sulfur sensitizer may be a known compound and examples thereof include, in addition to the sulfur compound contained in gelatin, various sulfur compounds such as thiosulfates, thioureas, thiazoles and rhodanines. Preferred sulfur compounds are a thiosulfate and a thiourea compound. The amount of the sulfur sensitizer added varies depending upon various conditions such as the pH and the temperature at the chemical ripening and the size of silver halide grain. However, it is preferably from 10 −7  to 10 −2  mol. more preferably from 10 −5  to 10 −3  mol. per mol of silver halide. 
     The selenium sensitizer for use in the present invention may be a known selenium compound. The selenium sensitization is usually performed by adding a labile and/or non-labile selenium compound and stirring the emulsion at a high temperature of 40° C. or higher for a predetermined time. Examples of the labile selenium compound include the compounds described in JP-B-44-15748, JP-B-43-13489, JP-A-4-25832, JP-A-4-109240 and JP-A-4-324855. Among these, particularly preferred are the compounds represented by formulae (VIII) and (IX) of JP-A-4-324855. 
     The tellurium sensitizer for use in the present invention is a compound of forming silver telluride presumed to work out to a sensitization nucleus, on the surface or in the inside of a silver halide grain. The rate of the formation of silver telluride in a silver halide emulsion can be examined according to a method described in JP-A-5-313284. Examples of the tellurium sensitizer include diacyl tellurides, bis(oxycarbonyl) tellurides, bis(carbamoyl) tellurides, diacyl tellurides, bis(oxycarbonyl) ditellurides, bis(carbamoyl) ditellurides, compounds having a P═Te bond, tellurocarboxylates, Te-organyltellurocarboxylic acid esters, di(poly)tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P—Te bond, Te-containing heterocyclic rings, tellurocarbonyl compounds, inorganic tellurium compounds and colloidal tellurium. Specific examples thereof include the compounds described in U.S. Pat. Nos. 1,623,499, 3,320,069 and 3,772,031, British Patent Nos. 235,211, 1,121,496, 1,295,462 and 1,396,696, Canadian Patent No. 800,958, JP-A-4-204640, JP-A-3-53693, JP-A-4-271341, JP-A-4-333043, JP-A-5-303157,  J. Chem. Soc. Chem. Commun.,  635 (1980), ibid., 1102 (1979), ibid., 645 (1979),  J. Chem. Soc. Perkin. Trans.,  1, 2191 (1980), S. Patai (compiler),  The Chemistry of Organic Selenium and Tellurium Compounds,  Vol. 1 (1986), and ibid., Vol. 2 (1987). The compounds represented by formulae (II), (III) and (IV) of JP-A-5-313284 are particularly preferred. 
     The amount of the selenium or tellurium sensitizer used in the present invention varies depending on silver halide grains used or chemical ripening conditions. However, it is usually from 10 −8  to 10 −2  mol. preferably on the order of from 10 −7  to 10 −3  mol. per mol of silver halide. The conditions for chemical sensitization in the present invention are not particularly restricted. However, in general, the pH is from 5 to 8, the pAg is from 6 to 11, preferably from 7 to 10, and the temperature is from 40 to 95° C., preferably from 45 to 85° C. 
     Noble metal sensitizers for use in the present invention include gold, platinum, palladium and iridium, and particularly, gold sensitization is preferred. Examples of the gold sensitizers used in the present invention include chloroauric acid, potassium chloroaurate, potassium aurithiocyanate and gold sulfide. They can be used in an amount of about 10 −7  Mol to about 10 −2  Mol per mol of silver halide. 
     In the silver halide emulsion for use in the present invention, a cadmium salt, sulfite, lead salt or thallium salt may be allowed to be present together during formation or physical ripening of silver halide grains. 
     In the present invention, reduction sensitization may be used. Specific examples of the compound used in the reduction sensitization include an ascorbic acid, thiourea dioxide, stannous chloride, aminoiminomethanesulfinic acid, a hydrazine derivative, a borane compound, a silane compound and a polyamine compound. The reduction sensitization may be performed by ripening the grains while keeping the emulsion at a pH of 7 or more or at a pAg of 8.3 or less. Also, the reduction sensitization may be performed by introducing a single addition part of silver ion during the formation of grains. 
     To the silver halide emulsion of the present invention, a thiosulfonic acid compound may be added by the method described in European Patent 293917A. 
     In the heat-developable image-forming material of the present invention, one kind of silver halide emulsion may be used or two or more kinds of silver halide emulsions (for example, those different in the average grain size, different in the halogen composition, different in the crystal habit or different in the chemical sensitization conditions) may be used in combination. 
     The amount of the photosensitive silver halide used in the present invention is preferably from 0.01 to 0.5 mol. more preferably from 0.02 to 0.3 mol. still more preferably from 0.03 to 0.25 mol. per mol of the organic silver salt. The method and conditions for mixing photosensitive silver halide and organic silver salt which are prepared separately are not particularly limited as far as the effect of the present invention can be brought out satisfactorily. However, a method of mixing the silver halide grains and the organic silver salt after completion of respective preparations in a high-speed stirring machine, a ball mill, a sand mill, a colloid mill, a vibrating mill or a homogenizer or the like, or a method involving preparing organic silver salt while mixing therewith photosensitive silver halide after completion of the preparation in any timing during preparation of the organic silver salt, or the like may be used. 
     The heat-developable photosensitive material of the invention is required to have γ (the gradient of a straight line connecting the density points of 0.2 and 2.5 where the logarithm of the exposing amount is abscissa) of 5 or higher and 15 or lower after heat developing process. As a method to achieve this, there is a method for containing a nucleation agent in the photosensitive layer or other adjacent layer. 
     The heat-developable image-recording material of the present invention preferably contains an ultrahigh contrast agent, preferably in the image-forming layer and/or another layer adjacent thereto so as to obtain a high-contrast image. Preferred examples of the ultrahigh contrast agent for use in the present invention include substituted alkene derivatives represented by the formula (1), substituted isooxazole derivatives represented by the formula (2), specific acetal compounds represented by the formula (3) and hydrazine derivatives. 
     The substituted alkene derivatives represented by the formula (1), substituted isooxazole derivatives represented by the formula (2), specific acetal compounds represented by the formula (3) for use in the present invention will be explained below.                    
     In the general formula (1) R 1 , R 2  and R 3  each independently represents a hydrogen atom or a substituent, Z represents an election withdrawing group or a silyl group, and R 1  and Z, R 2  and R 3 , R 1  and R 2 , or R 3  and Z may be combined with each other to form a ring structure; in the formula (2), R 4  represents a subtituent; and in the formula (3), X and Y each independently represents a hydrogen atom or a substituent, A and B each independently represents an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic oxy group, a heterocyclic thio group or a heterocyclic amino group, and X and Y, or A and B may be combined with each other to form a ring structure. 
     The compound represented by the formula (1) is described in detail below. 
     In the formula (1), R 1 , R 2  and R 3  each independently represents a hydrogen atom or a substituent, and Z represents an electron withdrawing group or a silyl group. In the formula (1), R 1  and Z, R 2  and R 3 , R 1  and R 2 , or R 3  and Z may be combined with each other to form a ring structure. 
     When R 1 , R 2  or R 3  represents a substituent, examples of the substituent include a halogen atom (e.g., fluorine, chlorine, bromide, iodine), an alkyl group (including an aralkyl group, a cycloalkyl group and active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (including N-substituted nitrogen-containing heterocyclic group), a quaternized nitrogen-containing heterocyclic group (e.g., pyridinio group), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a carboxy group or a salt thereof, an imino group, an imino group substituted by N atom, a thiocarbonyl group, a sulfonylcarbamoyl group, an acylcarbamoyl group, a sulfamoylcarbamoyl group, a carbazoyl group, an oxalyl group, an oxamoyl group, a cyano group, a thiocarbamoyl group, a hydroxy group (or a salt thereof), an alkoxy group (including a group containing an ethyleneoxy group or propyleneoxy group repeating unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, an (alkoxy or aryloxy)carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an amino group, an (alkyl, aryl or heterocyclic)amino group, an acylamino group, a sulfonamido group, a ureido group, a thioureido group, an imido group, an (alkoxy or aryloxy)carbonylamino group, a sulfamoylamino group, a semicarbazide group, a thiosemicarbazide group, a hydrazino group, a quaternary ammonio group, an oxamoylamino group, an (alkyl or aryl)sulfonylureido group, an acylureido group, an acylsulfamoylamino group, a nitro group, a mercapto group or a salt thereof, an (alkyl, aryl or heterocyclic)thio group, an acylthio group, an (alkyl or aryl)sulfonyl group, an (alkyl or aryl)sulfinyl group, a sulfo group or a salt thereof, a sulfamnoyl group, an acylsulfamoyl group, a sulfonylsulfamoyl group or a salt thereof, a phosphoryl group, a group containing phosphoramide or phosphoric acid ester structure, a silyl group and a stannyl group. 
     These substituents each may further be substituted by any of the above-described substituents. 
     The electron withdrawing group represented by Z in the formula (1) is a substituent having a Hammett&#39;s substituent constant σp of a positive value, and specific examples thereof include a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted by N atom, a thiocarbonyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a nitro group, a halogen atom, a perfluoroalkyl group, a perfluoroalkanamido group, a sulfonamido group, an acyl group, a formyl group, a phosphoryl group, a carboxy group (or a salt thereof), a sulfo group (or a salt thereof), a heterocyclic group, an alkenyl group, an alkynyl group, an acyloxy group, an acylthio group, a sulfonyloxy group and an aryl group substituted by the above-described electron withdrawing group. The heterocyclic group is a saturated or unsaturated heterocyclic group and examples thereof include a pyridyl group, a quinolyl group, a pyrazinyl group, a quinoxalinyl group, a benzotriazolyl group, an imidazolyl group, a benzimidazolyl group, a hydantoin-1-yl group, a succinimido group and a phthalimido group. 
     The electron withdrawing group represented by Z in the formula (1) may further have a substituent and examples of the substituent include those described for the substituent which the substituent represented by R 1 , R 2  or R 3  in the formula (1) may have. 
     In the formula (1), R 1  and Z, R 2  and R 3 , R 1  and R 2 , or R 3  and Z may be combined with each other to form a ring structure. The ring structure formed is a non-aromatic carbocyclic ring or a non-aromatic heterocyclic ring. 
     The preferred range of the compound represented by the formula (1) is described below. 
     The silyl group represented by Z in the formula (1) is preferably a trimethylsilyl group, a t-butyldimethylsilyl group, a phenyldimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group or a trimethylsilyldimethylsilyl group. 
     The electron withdrawing group represented by Z in the formula (1) is preferably a group having a total carbon atom number of from 0 to 30 such as a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a thiocarbonyl group, an imino group, an imino group substituted by N atom, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a nitro group, a perfluoroalkyl group, an acyl group, a formyl group, a phosphoryl group, an acyloxy group, an acylthio group or a phenyl group substituted by any electron withdrawing group, more preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, an imino group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, a formyl group, a phosphoryl group, a trifluoromethyl group or a phenyl group substituted by any electron withdrawing group, still more preferably a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, an imino group or a carbamoyl group. 
     The group represented by Z in the formula (1) is preferably an electron withdrawing group. 
     The substituent represented by R 1 , R 2  or R 3 in the formula (1) is preferably a group having a total carbon atom number of from 0 to 30 and specific examples of the group include a group having the same meaning as the electron withdrawing group represented by Z in the formula (1), an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an arylamino group, a heterocyclic amino group, a ureido group, an acylamino group, a sulfonamido group and a substituted or unsubstituted aryl group. 
     In the formula (1), R 1  is preferably an electron withdrawing group, an aryl group, an alkylthio group, an alkoxy group, an acylamino group, a hydrogen atom or a silyl group. 
     When R 1  represents an electron withdrawing group, the electron withdrawing group is preferably a group having a total carbon atom number of from 0 to 30 such as a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a thiocarbonyl group, an imino group, an imino group substituted by N atom, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, a sulfamoyl group, a trifluoromethyl group, a phosphoryl group, a carboxy group (or a salt thereof), a saturated or unsaturated heterocyclic group, more preferably a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted by N atom, a sulfamoyl group, a carboxy group (or a salt thereof) or a saturated or unsaturated heterocyclic group, still more preferably a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group or a saturated or unsaturated heterocyclic group. 
     When R 1  represents an aryl group, the aryl group is preferably a substituted or unsubstituted phenyl group having a total carbon atom number of from 6 to 30. The substituent may be any substituent but an electron withdrawing substituent is preferred. 
     In the formula (1), R 1  is more preferably an electron withdrawing group or an aryl group. 
     The substituent represented by R 2  or R 3  in the formula (1) is preferably a group having the same meaning as the electron withdrawing group represented by Z in the formula (1), an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group or a substituted or unsubstituted phenyl group. 
     In the formula (1), it is more preferred that one of R 2  and R 3  is a hydrogen atom and the other is a substituent. The substituent is preferably an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group (particularly, a perfluoroalkanamido group), a sulfonamido group, a substituted or unsubstituted phenyl group or a heterocyclic group, more preferably a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group or a heterocyclic group, still more preferably a hydroxy group (or a salt thereof), an alkoxy group or a heterocyclic group. 
     In the formula (1), it is also preferred that Z and R or R 2  and R 3  form a ring structure. The ring structure formed is a non-aromatic carbocyclic ring or a non-aromatic heterocyclic ring, preferably a 5-, 6- or 7-membered ring structure having a total carbon atom number including those of substituents of from 1 to 40, more preferably from 3 to 30. 
     The compound represented by the formula (1) is more preferably a compound where Z represents a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, an imino group or a carbamoyl group, R 1  represents an electron withdrawing group or an aryl group, and one of R 2  and R 3  represents a hydrogen atom and the other represents a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group or a heterocyclic group, more preferably a compound where Z and R 1  form a non-aromatic 5-, 6- or 7-membered ring structure and one of R 2  and R 3  represents a hydrogen atom and the other represents a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group or a heterocyclic group. At this time, Z which forms a non-aromatic ring structure together with R 1  is preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group or a sulfonyl group and R 1  is preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted by N atom, an acylamino group or a carbonylthio group. 
     The compound represented by the formula (2) is described below. 
     In the formula (2), R 4  represents a substituent. Examples of the substituent represented by R 4  include those described for the substituent represented by R 1 , R 2  or R 3 in the formula (1). 
     The substituent represented by R 4  is preferably an electron withdrawing group or an aryl group. When R 4  represents an electron withdrawing group, the electron withdrawing group is preferably a group having a total carbon atom number of from 0 to 30 such as a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, a sulfamoyl group, a trifluoromethyl group, a phosphoryl group, an imino group or a saturated or unsaturated heterocyclic group, more preferably a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, an alkylsulfonyl group, an aryLsulfonyl group or a heterocyclic group, still more preferably a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group or a heterocyclic group. 
     When R 4  represents an aryl group, the aryl group is preferably a substituted or unsubstituted phenyl group having a total carbon atom number of from 0 to 30. Examples of the substituent include those described for the substituent represented by R 1 , R 2  or R 3  in the formula (1). 
     R 4  is more preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, a heterocyclic group or a substituted or unsubstituted phenyl group, most preferably a cyano group, a heterocyclic group or an alkoxycarbonyl group. 
     The compound represented by the formula (3) is described in detail below. 
     In the formula (3), X and Y each independently represents a hydrogen atom or a substituent, and A and B each independently represents an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic thio group, a heterocyclic oxy group or a heterocyclic amino group, and X and Y or A and B may be combined with each other to form a ring structure. 
     Examples of the substituent represented by X or Y in the formula (3) include those described for the substituent represented by R 1 , R 2  or R 3  in the formula (1). Specific examples thereof include an alkyl group (including a perfluoroalkyl group and a trichloromethyl group), an aryl group, a heterocyclic group, a halogen atom, a cyano group, a nitro group, an alkenyl group, an alkynyl group, an acyl group, a formyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an imino group, an imino group substituted by N atom, a carbamoyl group, a thiocarbonyl group, an acyloxy group, an acylthio group, an acylamino group, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, a phosphoryl group, a carboxy group (or a salt thereof), a sulfo group (or a salt thereof), a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group and a silyl group. 
     These groups each may further have a substituent. X and Y may be combined with each other to form a ring structure and the ring structure formed may be either a non-aromatic carbocyclic ring or a non-aromatic heterocyclic ring. 
     In the formula (3), the substituent represented by X or Y is preferably a substituent having a total carbon number of from 1 to 40, more preferably from 1 to 30, such as a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted by N atom, a thiocarbonyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a nitro group, a perfluoroalkyl group, an acyl group, a formyl group, a phosphoryl group, an acylamino group, an acyloxy group, an acylthio group, a heterocyclic group, an alkylthio group, an alkoxy group or an aryl group. 
     In the formula (3), X and Y each is more preferably a cyano group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, an acyl group, a formyl group, an acylthio group, an acylamino group, a thiocarbonyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an imino group, an imino group substituted by N atom, a phosphoryl group, a trifluoromethyl group, a heterocyclic group or a substituted phenyl group, still more preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, an acylthio group, an acylamino group, a thiocarbonyl group, a formyl group, an amino group, an imino group substituted by N atom, a heterocyclic group or a phenyl group substituted by any electron withdrawing group. 
     X and Y are also preferably combined with each other to form a non-aromatic carbocyclic ring or a non-aromatic heterocyclic ring. The ring structure formed is preferably a 5-, 6- or 7-membered ring having a total carbon atom number of from 1 to 40, more preferably from 3 to 30. X and Y for forming a ring structure each is preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted by N atom, an acylamino group or a carbonylthio group. 
     In the formula (3), A and B each independently represents an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic thio group, a heterocyclic oxy group or a heterocyclic amino group, which may be combined with each other to form a ring structure. Those represented by A and B in the formula (3) are preferably a group having a total carbon atom number of from 1 to 40, more preferably from 1 to 30, and the group may further have a substituent. 
     In the formula (3), A and B are more preferably combined with each other to form a ring structure. The ring structure formed is preferably a 5-, 6- or 7-membered non-aromatic heterocyclic ring having a total carbon atom number of from 1 to 40, more preferably from 3 to 30. Examples of the linked structure (—A—B—) formed by A and B include —O—(CH 2 ) 2 —O—, —O—(CH 2 ) 3 —O—, —S—(CH 2 ) 2 —S—, —S—(CH 2 ) 3 —S—, —S—ph—S—, —N(CH 3 )—(CH 2 ) 2 —O—, —N(CH 3 )—(CH 2 ) 2 —S—, —O—(CH 2 ) 2 —S—, —O—(CH 2 ) 3 —S—, —N (CH 3 )—ph—O—, —N(CH 3 )—ph—S— and —N(ph)—(CH 2 ) 2 —S—. 
     Into the compound represented by the formula (1), (2) or (3) for use in the present invention, an adsorptive group capable of adsorbing to silver halide may be integrated. Examples of the adsorptive group include the groups described in U.S. Pat. Nos. 4,385,108 and 4,459,347, JP-A-59-195233, JP-A-59-200231, JP-A-59-201045, JP-A-59-201046, JP-A-59-201047, JP-A-59-201048, JP-A-59-201049, JP-A-61-170733, JP-A-61-270744, JP-A-62-948, JP-A-63-234244, JP-A-63-234245 and JP-A-63-234246, such as an alkylthio group, an arylthio group, a thiourea group, a thioamide group, a mercaptoheterocyclic group and a triazole group. The adsorptive group to silver halide may be formed into a precursor. Examples of the precursor include the groups described in JP-A-2-285344. 
     Into the compound represented by the formula (1), (2) or (3) for use in the present invention, a ballast group or polymer commonly used in immobile photographic additives such as a coupler may be integrated, preferably a ballast group is incorporated. The ballast group is a group having 8 or more carbon atoms and being relatively inactive to the photographic properties. Examples of the ballast group include an alkyl group, an aralkyl group, an alkoxy group, a phenyl group, an alkylphenyl group, a phenoxy group and an alkylphenoxy group. Examples of the polymer include those described in JP-A-1-100530. 
     The compound represented by the formula (1), (2) or (3) for use in the present invention may contain a cationic group (specifically, a group containing a quaternary ammonio group or a nitrogen-containing heterocyclic group containing a quaternized nitrogen atom), a group containing an ethyleneoxy group or a propyleneoxy group as a repeating unit, an (alkyl, aryl or heterocyclic)thio group, or a dissociative group capable of dissociation by a base (e.g., carboxy group, sulfo group, acylsulfamoyl group, carbamoylsulfamoyl group), preferably a group containing an ethyleneoxy group or a propyleneoxy group as a repeating unit, or an (alkyl, aryl or heterocyclic)thio group. Specific examples of these groups include the compounds described in JP-A-7-234471, JP-A-5-333466, JP-A-6-19032, JP-A-6-19031, JP-A-5-45761, U.S. Pat. Nos. 4,994,365 and 4,988,604, JP-A-3-259240, JP-A-7-5610, JP-A-7-244348 and German Patent No. 4,006,032. 
     Specific examples of the compounds represented by the formulae (1) to (3) for use in the present invention are shown below. However, the present invention is by no means limited to the following compounds.                                                                                                                                                                    
     The compounds represented by the formulae (1) to (3) for use in the present invention each may be used after dissolving it in water or an appropriate organic solvent such as an alcohol (e.g., methanol, ethanol, propanol, fluorinated alcohol), a ketone (e.g., acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide or methyl cellosolve. 
     Also, the compounds represented by the formulae (1) to (3) for use in the present invention each may be dissolved by an already well-known emulsification dispersion method using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically formed into an emulsified dispersion before use. Furthermore, the compounds represented by the formulae (1) to (3) each may be used after dispersing the powder of the compound in an appropriate solvent such as water by a method known as a solid dispersion method, using a ball mill, a colloid mill or an ultrasonic wave. 
     The compounds represented by the formulae (1) to (3) for use in the present invention each may be added to a layer in the image-recording layer side on the support, namely, an image-forming layer, or any other layers; however, the compounds each is preferably added to an image-forming layer or a layer adjacent thereto. 
     The addition amount of the compound represented by the formula (1), (2) or (3) for use in the present invention is preferably from 1×10 −6  to 1 mol. more preferably from 1×10 −5  to 5×10 −1  mol. most preferably from 2×10 −5  to 2×10 −1  mol. per mol of silver. 
     The compounds represented by formulae (1) to (3) can be easily synthesized according to known methods and may be synthesized by referring, for example, to U.S. Pat. Nos. 5,545,515, 5,635,339 and 5,654,130, International Patent Publication W097/34196 or Japanese Patent Application Nos. 9-354107, 9-309813 and 9-272002. 
     The compounds represented by the formulae (1) to (3) may be used individually or in combination of two or more thereof. In addition to these compounds, a compound described in U.S. Pat. Nos. 5,545,515, 5,635,339 and 5,654,130, International Patent Publication WO97/34196, U.S. Pat. No. 5,686,228 or Japanese Patent Application Nos. 8-279962, 9-228881, 9-273935, 9-354107, 9-309813, 9-296174, 9-282564, 9-2720021, 9-272003 and 9-332388 may also be used in combination. They can also be used in combination with such hydrazine derivatives as mentioned below. 
     The hydrazine derivative for use in the present invention is preferably a compound represented by the following general formula (H):                    
     In the formula, R represents an aliphatic group, an aromatic group or a heterocyclic group, R 11  represents a hydrogen atom or a block group, G 1  represents —CO—, —COCO—, —C(═S)—, —SO 2 —, —SO—, —PO(R 3 )— (wherein R 13  is a group selected from the groups within the range defined for R 11 , and R 13  may be different from R 11 ), or an iminomethylene group, A 1  and A 2  both represents a hydrogen atom or one represents a hydrogen atom and the other represents a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, or a substituted or unsubstituted acyl group, and m 1  represents 0 or 1 and when m 1  is 0, R 1  represents an aliphatic group, an aromatic group or a heterocyclic group. 
     In the formula (H), the aliphatic group represented by R 12  is preferably a substituted or unsubstituted, linear, branched or cyclic alkyl group, an alkenyl group or an alkynyl group having from 1 to 30 carbon atoms. 
     In the formula (H), the aromatic group represented by R 12  is a monocyclic or condensed cyclic aryl group, and examples thereof include a phenyl group and a naphthalene group. The heterocyclic group represented by R 12  is a monocyclic or condensed cyclic, saturated or unsaturated, aromatic or non-aromatic heterocyclic group, and examples thereof include a pyridine ring, a pyrimidine ring, an imidazole ring, a pyrazole ring, a quinoline ring, an isoquinoline ring, a benzimidazole ring, a thiazole ring, a benzothiazole ring, a piperidine ring, a triazine ring, a morpholino ring, a piperidine ring and a piperazine ring. 
     R 12  is preferably an aryl group or an alkyl group. 
     R 12  may be substituted and representative examples of the substituent include a halogen atom (e.g., fluorine, chlorine, bromine, iodine), an alkyl group (including an aralkyl group, a cycloalkyl group and an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a heterocyclic group containing a quaternized nitrogen atom (e.g., pyridinio group), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a carboxy group or a salt thereof, a sulfonylcarbamoyl group, an acylcarbamoyl group, a sulfamoylcarbamoyl group, a carbazoyl group, an oxalyl group, an oxamoyl group, a cyano group, a thiocarbamoyl group, a hydroxy group, an alkoxy group (including a group containing an ethyleneoxy group or a propylene oxy group repeating unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, an (alkoxy or aryloxy)carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an amino group, an (alkyl, aryl or heterocyclic)amino group, a N-substituted nitrogen-containing heterocyclic group, an acylamino group, a sulfonamido group, a ureido group, a thioureido group, an imido group, an (alkoxy or aryloxy)carbonylamino group, a sulfamoylamino group, a semicarbazide group, thiosemicarbazide group, a hydrazino group, a quaternary ammonio group, an oxamoylamino group, an (alkyl or aryl)sulfonylureido group, an acylureido group, an acylsulfamoylamino group, a nitro group, a mercapto group, an (alkyl, aryl or heterocyclic)thio group, an (alkyl or aryl)sulfonyl group, an (alkyl or aryl)sulfinyl group, a sulfo group or a salt thereof, a sulfamoyl group, an acylsulfamoyl group, a sulfonylsulfamoyl group or a salt thereof, and a group containing a phosphoramido or phosphoric acid ester structure. 
     These substituents each may further be substituted by any of the above-described substituents. 
     When R 12  represents an aromatic group or a heterocyclic group, the substituent of R 2  is preferably an alkyl group (including an active methylene group), an aralkyl group, a heterocyclic group, a substituted amino group, an acylamino group, a sulfonamido group, a ureido group, a sulfamoylamino group, an imido group, a thioureido group, a phosphoramido group, a hydroxy group, an alkoxy group, an aryloxy group, an acyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a carboxy group (including a salt thereof), an (alkyl, aryl or heterocyclic)thio group, a sulfo group (including a salt thereof), a sulfamoyl group, a halogen atom, a cyano group or a nitro group. 
     When R 12  represents an aliphatic group, the substituent is preferably an alkyl group, an aryl group, a heterocyclic group, an amino group, an acylamino group, a sulfonamido group, a ureido group, a sulfamoylamino group, an imido group, a thioureido group, a phosphoramido group, a hydroxy group, an alkoxy group, an aryloxy group, an acyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a carboxy group (including a salt thereof), an (alkyl, aryl or heterocyclic)thio group, a sulfo group (including a salt thereof), a sulfamoyl group, a halogen atom, a cyano group or a nitro group. 
     In the formula (H), R 11  represents a hydrogen atom or a block group. The block group is specifically an aliphatic group (specifically, an alkyl group, an alkenyl group or an alkynyl group), an aromatic group (e.g., a monocyclic or condensed cyclic aryl group), a heterocyclic group, an alkoxy group, an aryloxy group, an amino group or a hydrazino group. 
     The alkyl group represented by R 11  is preferably a substituted or unsubstituted alkyl group having from 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a trifluoromethyl group, a difluoromethyl group, a 2-carboxytetrafluoroethyl group, a pyridiniomethly group, a difluoromethoxymethyl group, a difluorocarboxymethyl group, a 3-hydroxypropyl group, a 3-methanesulfonamidopropyl group, a phenylsulfonylmethyl group, an o-hydroxybenzyl group, a methoxymethyl group, a phenoxymethyl group, a 4-ethlphenoxymethyl group, a phenylthiomethyl group, a t-butyl group, a dicyanomethyl group, a diphenylmethyl group, a triphenylmethyl group, a methoxycarbonyldiphenylmethyl group, a cyanodiphenylmethyl group and a methylthiodiphenylmethyl group. The alkenyl group is preferably an alkenyl group having from 1 to 10 carbon atoms, and examples thereof include a vinyl group, a 2-ethoxycarbonylvinyl group and a 2-trifluoro-2-methoxycarbonylvinyl group. The alkynyl group is an alkynyl group having from 1 to 10 carbon atoms, and examples thereof include an ethynyl group and a 2-methoxycarbonylethynyl group. The aryl group is preferably a monocyclic or condensed cyclic aryl group, more preferably an aryl group containing a benzene ring, and examples thereof include a phenyl group, a perfluorophenyl group, a 3,5-dichlorophenyl group, a 2-methanesulfonamidophenyl group, a 2-carbamoylphenyl group, a 4,5-dicyanophenyl group, a 2-hydroxymethylphenyl group, 2,6-dichloro-4-cyanophenyl group and 2-chloro-5-octylsulfamoylphenyl group. 
     The heterocyclic group is preferably a 5- or 6-membered, saturated or unsaturated, monocyclic or condensed heterocyclic group containing at least one nitlogen, oxygen or sulfur atom, and examples thereof include a morpholino group, a piperidino group (N-substituted), an imidazolyl group, an indazolyl group (e.g., 4-nitroindazolyl group), a pyrazolyl group, a triazolyl group, a benzoimidazolyl group, a tetrazolyl group, a pyridyl group, a pyridinio group (e.g., N-methyl-3-pyridinio group), a quinolinio group and a quinolyl group. 
     The alkoxy group is preferably an alkoxy group having from 1 to 8 carbon atoms, and examples thereof include a methoxy group, a 2-hydroxyethoxy group, a benzyloxy group and a t-butoxy group. The aryloxy group is preferably a substituted or unsubstituted phenoxy group, and the amino group is preferably an unsubstituted amino group, an alkylamino group having from 1 to 10 carbon atoms, an arylamino group or a saturated or unsaturated heterocyclic amino group (including a nitrogen-containing heterocyclic amino group containing a quaternized nitrogen atom). Examples of the amino group include 2,2,6,6-tetramethylpiperidin-4-ylamino group, a propylamino group, a 2-hydroxyethylamino group, an anilino group, an o-hydroxyanilino group, a 5-benzotriazolylamino group and a N-benzyl-3-pyridinioamino group. The hydrazino group is preferably a substituted or unsubstituted hydrazino group or a substituted or unsubstituted phenylhydrazino group (e.g., 4-benzenesulfonamidophenylhydrazino group). 
     The group represented by R 11  may be substituted, and examples of the substituent include those described as the substituent of R 12 . 
     In the formula (H), R 11  may be one which cleaves the G 1 —R 11  moiety from the residual molecule and causes a cyclization reaction to form a cyclic structure containing the atoms in the —G 1 —R 11  moiety, and examples thereof include those described in JP-A-63-29751. 
     Into the hydrazine derivative represented by the formula (H), an adsorptive group capable of adsorbing to silver halide may be integrated. Examples of the adsorptive group include the groups described in U.S. Pat. Nos. 4,385,108 and 4,459,347, JP-A-59-195233, JP-A-59-200231, JP-A-59-201045, JP-A-59-201046, JP-A-59-201047, JP-A-59-201048, JP-A-59-201049, JP-A-61-170733, JP-A-61-270744, JP-A-62-948, JP-A-63-234244, JP-A-63-234245 and JP-A-63-234246, such as an alkylthio group, an arylthio group, a thiourea group, a thioamide group, a mercaptoheterocyclic group and a triazole group. The adsorptive group to silver halide may be formed into a precursor. Examples of the precursor include the groups described in JP-A-2-285344. 
     In the formula (H), R 11  or R 12  may be one into which a ballast group or polymer commonly used in immobile photographic additives such as a coupler may be integrated. The ballast group is a group having 8 or more carbon atoms and being relatively inactive to the photographic properties. Examples of the ballast group include an alkyl group, an aralkyl group, an alkoxy group, a phenyl group, an alkylphenyl group, a phenoxy group and an alkylphenoxy group. Examples of the polymer include those described in JP-A-1-100530. 
     In the formula (H), R 11  or R 2  may contain a plurality of hydrazino groups as the substituent. At this time, the compound represented by the formula (H) is a polymer product with respect to the hydrazino group, and specific examples thereof include the compounds described in JP-A-64-86134, JP-A-4-16938, JP-A-5-197091, W095-32452, WO95-32453, Japanese Patent Application Nos. 7-351132, 7-351269, 7-351168, 7-351287 and 9-351279. 
     In the formula (H), R 11  or R 12  may contain a cationic group (specifically, a group containing a quaternary ammonio group or a nitrogen-containing heterocyclic group containing a quaternized nitrogen atom), a group containing an ethyleneoxy group or a propyleneoxy group as a repeating unit, an (alkyl, aryl or heterocyclic)thio group, or a dissociative group capable of dissociation by a base (e.g., carboxy group, sulfo group, acylsulfamoyl group, carbamoylsulfamoyl group). Examples of the compound containing such a group include the compounds described in JP-A-7-234471, JP-A-5-333466, JP-A-6-19032, JP-A-6-19031, JP-A-5-45761, U.S. Pat. Nos. 4,994,365 and 4,988,604, JP-A-3-259240, JP-A-7-5610, JP-A-7-244348 and German Patent No. 4,006,032. 
     In the formula (H), A 1  and A 2  each represents a hydrogen atom, an alkyl- or arylsulfonyl group having 20 or less carbon atoms (preferably a phenylsulfonyl group or a phenylsulfonyl group substituted such that the sum of Hammett&#39;s substituent constants is −0.5 or more), an acyl group having 20 or less carbon atoms (preferably a benzoyl group, a benzoyl group substituted such that the sum of Hammett&#39;s substituent constants is −0.5 or more, or a linear, branched or cyclic, substituted or unsubstituted aliphatic acyl group (examples of the substituent include a halogen atom, an ether group, a sulfonamido group, a carbonamido group, a hydroxy group, a carboxy group and a sulfo group)). 
     A 1  and A 2  each is most preferably a hydrogen atom. 
     A particularly preferred embodiment of the hydrazine derivative for use in the present invention is described below. 
     R 12  is preferably a phenyl group or a substituted alkyl group having from 1 to 3 carbon atoms. 
     When R 12  represents a phenyl group, the substituent therefor is preferably a nitro group, an alkoxy group, an alkyl group, an acylamino group, a ureido group, a sulfonamido group, a thioureido group, a carbamoyl group, a sulfamoyl group, a carboxy group (or a salt thereof), a sulfo group (or a salt thereof), an alkoxycarbonyl group or a chlorine atom. 
     When R 12  represents a substituted phenyl group, the substituent is preferably substituted directly or through a linking group by at least one of a ballast group, an adsorptive group to silver halide, a group containing a quaternary ammonio group, a nitrogen-containing heterocyclic group containing a quaternized nitrogen, a group containing an ethyleneoxy group as a repeating unit, an (alkyl, aryl or heterocyclic)thio group, a nitro group, an alkoxy group, an acylamino group, a sulfonamido group, a dissociative group (e.g., carboxy group, sulfo group, acylsulfamoyl group, carbamoylsulfamoyl group) and a hydrazino group capable of forming a polymer product (a group represented by —NHNH—G 1 —R 11 ). 
     When R 12  represents a substituted alkyl group having from 1 to 3 carbon atoms, R 12 is more preferably a substituted methyl group, more preferably a disubstituted or trisubstituted methyl group, and the substituent therefor is preferably a methyl group, a phenyl group, a cyano group, an (alkyl, aryl or heterocyclic)thio group, an alkoxy group, an aryloxy group, a chlorine atom, a heterocyclic group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, an amino group, an acylamino group or a sulfonamido group, more preferably a substituted or unsubstituted phenyl group. 
     When R 12  represents a substituted methyl group, R 12  is preferably a t-butyl group, a dicyanomethyl group, a dicyanophenylmethyl group, a triphenylmethyl group (trityl group), a diphenylmethyl group, a methoxycarbonyldiphenylmethyl group, a cyanodiphenylmethyl group, a methylthiodiphenylmethyl group or a cyclopropyldiphenylmethyl group, most preferably a trityl group. 
     In the formula (H), R 12  is most preferably a substituted phenyl group. 
     In the formula (H), m 1  represents 1 or 0. When m 1  is 0, R 11  is an aliphatic group, an aromatic group or a heterocyclic group, preferably a phenyl group or a substituted alkyl group having from 1 to 3 carbon atoms, and these groups have the same preferred range as described above for R 12 . 
     m 1  is preferably 1. 
     The preferred embodiment of the group represented by R 11  is described below. When R 12  is a phenyl group and G 1  is —CO— group, R 11  is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, more preferably a hydrogen atom, an alkyl group or an aryl group, and most preferably a hydrogen atom or an alkyl group. In the case where R 1  represents an alkyl group, the substituent therefor is preferably a halogen atom, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group or a carboxy group. 
     When R 12  is a substituted methyl group and G 1  is —CO— group, R 11  is preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkoxy group or an amino group (e.g., unsubstituted amino group, alkylamino group, arylamino group, heterocyclic amino group), more preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an alkylamino group, an arylamino group or a heterocyclic amino group. When G 1  is —COCO— group, R 11  is preferably, irrespective of R 12 , an alkoxy group, an aryloxy group or an amino group, more preferably a substituted amino group, specifically, an alkylamino group, an arylamino group or a saturated or unsaturated heterocyclic amino group. 
     When G 1  is —SO 2 — group, R 11  is preferably, irrespective of R 12 , an alkyl group, an aryl group or a substituted amino group. 
     In the formula (H), G 1  is preferably —CO— or —COCO— group, more preferably —CO—group. 
     Specific examples of the compound represented by the formula (H) are shown below. However, the present invention is by no means limited to those compounds. 
     
       
         
           
               
             
               
                   
               
             
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                           X = 
                           —H 
                         —C 2 F 4 —COOH or (—C 2 F 4 —COO ⊖ K ⊕ ) 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  1 
                 3-NHCO—C 9 H 19 (n) 
                 1a 
                 1b 
                 1c 
                 1d 
               
               
                   
               
               
                  2 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 2a 
                 2b 
                 2c 
                 2d 
               
               
                   
               
               
                  3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 3a 
                 3b 
                 3c 
                 3d 
               
               
                   
               
               
                  4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 4a 
                 4b 
                 4c 
                 4d 
               
               
                   
               
               
                  5 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 5a 
                 5b 
                 5c 
                 5d 
               
               
                   
               
               
                  6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 6a 
                 6b 
                 6c 
                 6d 
               
               
                   
               
               
                  7 
                 2,4-(CH 3 ) 2 -3- 
                 7a 
                 7b 
                 7c 
                 7d 
               
               
                   
                 SC 2 H 4 —(OC 2 H 4 ) 4 —OC 8 H 17   
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                           X = 
                           —H 
                           —CF 2 H 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  8 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 8a 
                 8e 
                 8f 
                 8g 
               
               
                   
               
               
                  9 
                 6-OCH 3 -3-C 5 H 11 (t) 
                 9a 
                 9e 
                 9f 
                 9g 
               
               
                   
               
               
                  10 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 10a 
                 10e 
                 10f 
                 10g 
               
               
                   
               
               
                  11 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 11a 
                 11e 
                 11f 
                 11g 
               
               
                   
               
               
                  12 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 12a 
                 12e 
                 12f 
                 12g 
               
               
                   
               
               
                  13 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 13a 
                 13e 
                 13f 
                 13g 
               
               
                   
               
               
                  14 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 14a 
                 14e 
                 14f 
                 14g 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 X = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                           Y = 
                           —CHO 
                           —COCF 3   
                           —SO 2 CH 3   
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  15 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 15a 
                 15h 
                 15i 
                 15j 
               
               
                   
               
               
                  16 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 16a 
                 16h 
                 16i 
                 16j 
               
               
                   
               
               
                  17 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 17a 
                 17h 
                 17i 
                 17j 
               
               
                   
               
               
                  18 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 18a 
                 18h 
                 18i 
                 18j 
               
               
                   
               
               
                  19 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 19a 
                 19h 
                 19i 
                 19j 
               
               
                   
               
               
                  20 
                 3-NHSO 2 NH—C 8 H 17   
                 20a 
                 20h 
                 20i 
                 20j 
               
               
                   
               
               
                  21 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 21a 
                 21h 
                 21i 
                 21j 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                           —H 
                           —CF 3   
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  22 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 22a 
                 22h 
                 22k 
                 22l 
               
               
                   
               
               
                  23 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 23a 
                 23h 
                 23k 
                 23l 
               
               
                   
               
               
                  24 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 24a 
                 24h 
                 24k 
                 24l 
               
               
                   
               
               
                  25 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 25a 
                 25h 
                 25k 
                 25l 
               
               
                   
               
               
                  26 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 26a 
                 26h 
                 26k 
                 26l 
               
               
                   
               
               
                  27 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 27a 
                 27h 
                 27k 
                 27l 
               
               
                   
               
               
                  28 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 28a 
                 28h 
                 28k 
                 28l 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                           Y = 
                           —H 
                           —CH 2 OCH 3   
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  29 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 29a 
                 29m 
                 29n 
                 29f 
               
               
                   
               
               
                  30 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 30a 
                 30m 
                 30n 
                 30f 
               
               
                   
               
               
                  31 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 31a 
                 31m 
                 31n 
                 31f 
               
               
                   
               
               
                  32 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 32a 
                 32m 
                 32n 
                 32f 
               
               
                   
               
               
                  33 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 33a 
                 33m 
                 33n 
                 33f 
               
               
                   
               
               
                  34 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 34a 
                 34m 
                 34n 
                 34f 
               
               
                   
               
               
                  35 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 35a 
                 35m 
                 35n 
                 35f 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                           Y = 
                           —H 
                           —CF 2 SCH 3   
                           —CONHCH 3   
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  36 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 36a 
                 36o 
                 36p 
                 36q 
               
               
                   
               
               
                  37 
                 2-OCH 3 - 
                 37a 
                 37o 
                 37p 
                 37q 
               
               
                   
                 4-NHSO 2 C 12 H 25   
               
               
                  38 
                 3-NHCOC 11 H 23 - 
                 38a 
                 38o 
                 38p 
                 38q 
               
               
                   
                 4-NHSO 2 CF 3   
               
               
                   
               
               
                  39 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 39a 
                 39o 
                 39p 
                 39q 
               
               
                   
               
               
                  40 
                 4-OCO(CH 2 ) 2 COOC 6 H 13   
                 40a 
                 40o 
                 40p 
                 40q 
               
               
                   
               
               
                  41 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 41a 
                 41o 
                 41p 
                 41q 
               
               
                   
               
               
                  42 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 42a 
                 42o 
                 42p 
                 42q 
               
               
                   
               
            
           
           
               
               
            
               
                  43 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  44 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  45 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  46 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  47 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  48 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  49 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  50 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  51 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  52 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  53 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                           —H 
                           —CH 2 OCH 3   
                 
                   
                     
                     
                         
                         
                     
                   
                 
                           —CONHC 3 H 7   
               
               
                   
               
               
                  54 
                 2-OCH 3   
                 54a 
                 54m 
                 54r 
                 54s 
               
               
                  55 
                 2-OCH 3   
                 55a 
                 55m 
                 55r 
                 55s 
               
               
                   
                 5-C 8 H 17 (t) 
               
               
                  56 
                 4-NO 2   
                 56a 
                 56m 
                 56r 
                 56s 
               
               
                  57 
                 4-CH 3   
                 57a 
                 57m 
                 57r 
                 57s 
               
               
                   
               
               
                  58 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 58a 
                 58m 
                 58r 
                 58s 
               
               
                   
               
               
                  59 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 59a 
                 59m 
                 59r 
                 59s 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                 —H 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  60 
                 2-OCH 3   
                 60a 
                 60c 
                 60f 
                 60g 
               
               
                   
                 5-OCH 3   
               
               
                  61 
                 4-C 8 H 17 (t) 
                 61a 
                 61c 
                 61f 
                 61g 
               
               
                  62 
                 4-OCH 3   
                 62a 
                 62c 
                 62f 
                 62g 
               
               
                  63 
                 3-NO 2   
                 63a 
                 63c 
                 63f 
                 63g 
               
               
                   
               
               
                  64 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 64a 
                 64c 
                 64f 
                 64g 
               
               
                   
               
               
                  65 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 65a 
                 65c 
                 65f 
                 65g 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R B  = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         R A  = 
                 —H 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  66 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 66a 
                 66u 
                 66v 
                 66t 
               
               
                   
               
               
                  67 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 67a 
                 67u 
                 67v 
                 67t 
               
               
                   
               
               
                  68 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 68a 
                 68u 
                 68v 
                 68t 
               
               
                   
               
               
                  69 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 69a 
                 69u 
                 69v 
                 69t 
               
               
                   
               
               
                  70 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 70a 
                 70u 
                 70v 
                 70t 
               
               
                   
               
               
                  71 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 71a 
                 71u 
                 71v 
                 71t 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R B  = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         R A  = 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 —OC 4 H 9 (t) 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  72 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 72s 
                 72x 
                 72y 
                 72w 
               
               
                   
               
               
                  73 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 73s 
                 73x 
                 73y 
                 73w 
               
               
                   
               
               
                  74 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 74s 
                 74x 
                 74y 
                 74w 
               
               
                   
               
               
                  75 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 75s 
                 75x 
                 75y 
                 75w 
               
               
                   
               
               
                  76 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 76s 
                 76x 
                 76y 
                 76w 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
               
                   
               
               
                  77 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  78 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  79 
                 —CH 2 OCH 2 CH 2 SCH 2 CH 2 OCH 3   
               
               
                  80 
                 —CF 2 CF 2 COOH 
               
               
                   
               
               
                  81 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  82 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  83 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  84 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  85 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  86 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  87 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  88 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  89 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  90 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  91 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  92 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  93 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                  94 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 —CH 2 —Cl 
               
               
                   
               
               
                  95 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 95-1 
                 95-2 
                 95-3 
                 95-4 
               
               
                   
               
               
                  96 
                 4-COOH 
                 96-1 
                 96-2 
                 96-3 
                 96-4 
               
               
                   
               
               
                  97 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 97-1 
                 97-2 
                 97-3 
                 97-4 
               
               
                   
               
               
                  98 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 98-1 
                 98-2 
                 98-3 
                 98-4 
               
               
                   
               
               
                  99 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 99-1 
                 99-2 
                 99-3 
                 99-4 
               
               
                   
               
               
                 100 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 100-1 
                 100-2 
                 100-3 
                 100-4 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 X = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 101 
                 4-NO 2   
                 101-5 
                 101-6 
                 101-7 
                 101y 
               
               
                 102 
                 2,4-OCH 3   
                 102-5 
                 102-6 
                 102-7 
                 102y 
               
               
                   
               
               
                 103 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 103-5 
                 103-6 
                 103-7 
                 103y 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 X = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 104 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 104-8 
                 104-9 
                 104w′ 
                 104x 
               
               
                   
               
               
                 105 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 105-8 
                 105-9 
                 105w′ 
                 105x 
               
               
                   
               
            
           
           
               
            
               
                 Y—NH NH—X 
               
            
           
           
               
               
            
               
                   
                 X = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 106 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 106-10 
                 106a 
                 106m 
                 106y 
               
               
                   
               
               
                 107 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 107-10 
                 107a 
                 107m 
                 107y 
               
               
                   
               
               
                 108 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 108-10 
                 108a 
                 108m 
                 108y 
               
               
                   
               
               
                 109 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 109-10 
                 109a 
                 109m 
                 109y 
               
               
                   
               
               
                 110 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 110-10 
                 110a 
                 110m 
                 110y 
               
               
                   
               
               
                 111 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 111-10 
                 111a 
                 111m 
                 111y 
               
               
                   
               
            
           
           
               
            
               
                 Y—NH NH—X 
               
            
           
           
               
               
            
               
                   
                 X = 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                         Y = 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 112 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 112-11 
                 112-12 
                 112-13 
                 112-14 
               
               
                   
               
               
                 113 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 113-11 
                 113-12 
                 113-13 
                 113-14 
               
               
                   
               
               
                 114 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 114-11 
                 114-12 
                 114-13 
                 114-14 
               
               
                   
               
               
                 115 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 115-11 
                 115-12 
                 115-13 
                 115-14 
               
               
                   
               
               
                 116 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 116-11 
                 116-12 
                 116-13 
                 116-14 
               
               
                   
               
               
                 117 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 117-11 
                 117-12 
                 117-13 
                 117-14 
               
               
                   
               
            
           
           
               
               
            
               
                 118 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 119 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 120 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 121 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 122 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 123 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 X = 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Ar = 
                 —OH 
                 —SH 
                 —NHCOCF 3   
                 —NHSO 2 CH 3   
                 —NHSO 2 ph 
                 —N(CH 3 ) 2   
               
               
                   
               
               
                 124 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 124a 
                 124b 
                 124c 
                 124d 
                 124e 
                 124f 
               
               
                   
               
               
                 125 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 125a 
                 125b 
                 125c 
                 125d 
                 125e 
                 125f 
               
               
                   
               
               
                 126 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 126a 
                 126b 
                 126c 
                 126d 
                 126e 
                 126f 
               
               
                   
               
               
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     The hydrazine derivatives represented by the formula (H) can be used alone or in any combination of two or more kinds of them. 
     In addition to the above-described hydrazine derivatives, the hydrazine derivatives described below may also be preferably used in the present invention (depending on the case, the hydrazine derivatives may be used in combination). Furthermore, the hydrazine derivative for use in the present invention can be synthesized by various methods described in the following patent publications. 
     Examples of the hydrazine derivative other than the hydrazine derivative described in the foregoing include the compounds represented by (Chem. 1) of JP-B-6-77138, specifically, compounds described at pages 3 and 4 of the publication; the compounds represented by the formula (I) of JP-B-6-93082, specifically, Compounds 1-38 described at pages 8 to 18 of the publication; the compounds represented by the formulae (4), (5) and (6) of JP-A-6-230497, specifically, Compounds 4-1 to 4-10 described at pages 25 and 26, Compounds 5-1 to 5-42 described at pages 28 to 36 and Compounds 6-1 to 6-7 described at pages 39 and 40 of the publication; the compounds represented by the formulae (1) and (2) of JP-A-6-289520, specifically, Compounds 1-1) to 1-17) and 2-1) described at pages 5 to 7 of the publication; the compounds represented by (Chem. 2) and (Chem. 3) of JP-A-6-313936, specifically, compounds described at pages 6 to 19 of the publication; the compound represented by (Chem. 1) of JP-A-6-313951, specifically, the compounds described at pages 3 to 5 of the publication; the compound represented by the formula (I) of JP-A-7-5610, specifically, Compounds I-1 to I-38 described at pages 5 to 10 of the publication; the compounds represented by the formula (II) of JP-A-7-77783, specifically, Compounds II-1 to II-102 described at pages 10 to 27 of the publication; the compounds represented by the formulae (H) and (Ha) of JP-A-7-104426, specifically, Compounds H-1 to H-44 described at pages 8 to 15 of the publication; the compounds characterized by having in the vicinity of the hydrazine group an anionic group or a nonionic group capable of forming an internal hydrogen bond with a hydrogen atom of hydrazine, described in JP-A-9-22082, particularly, the compounds represented by the formulae (A), (B), (C), (D), (E) and (F), specifically, Compounds N-1 to N-30 described in the publication; the compound represented by the formula (1) described in JP-A-9-22082, specifically, Compounds D-1 to D-55 described in the publication; various hydrazine derivatives described at pages 25 to 34 of  Kochi Gijutsu  ( Known Techniques ), pages 1 to 207, Aztech (issued on Mar. 22, 1991); and Compounds D-2 and D-39 described in JP-A-62-86354 (pages 6 and 7). 
     The hydrazine based nucleation agent for use in the present invention may be used after dissolving it in an appropriate organic solvent such as an alcohol (e.g., methanol, ethanol, propanol, fluorinated alcohol), a ketone (e.g., acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide or methyl cellosolve. 
     Also, the hydrazine based nucleation agent for use in the present invention each may be dissolved by an already well-known emulsification dispersion method using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically formed into an emulsified dispersion before use. Furthermore, they may be used after dispersing the powder of the hydrazine derivative in water by a method known as a solid dispersion method, using a ball mill, colloid mill or ultrasonic wave. 
     The hydrazine nucleation agent for use in the present invention may be added to any layers on the image-forming layer side on the support, i.e., the image-forming layer or other layers on that layer side; however, they are preferably added to an image-forming layer or a layer adjacent thereto. 
     The addition amount of the hydrazine derivatives for use in the present invention is preferably from 1×10 −6  to 1×10 −2  mol. more preferably from 1×10 −5  to 5×10 −3  mol. most preferably from 2−10 −5  to 5×10 −3  mol. per mol of silver. 
     In the present invention, a nucleation agent may be used in combination with the above-described ultrahigh contrast agent so as to form an ultrahigh contrast image. Examples thereof include amine compounds described in U.S. Pat. No. 5,545,505, specifically, AM-1 to AM-5; hydroxamic acids described in U.S. Pat. No. 5,545,507, specifically, HA-1 to HA-11; acrylonitriles described in U.S. Pat. No. 5,545,507, specifically, CN-1 to CN-13, hydrazine compounds described in U.S. Pat. No. 5,558,983, specifically, CA-1 to CA-6; and onium salts described in JP-A-9-297368, specifically, A-1 to A-42, B-1 to B-27 and C-1 to C-14. 
     The synthesis methods, addition methods and addition amounts of the aforementioned ultrahigh contrast agents and the contrast accelerators may be according to those described in the patent publications cited above. 
     For this invention, it is preferable to use an acid created from diphosphorus pentaoxide upon hydration or its salt together with the nucleation agent. As such an acid created from diphosphorus pentaoxide upon hydration or its salt, metaphosphoric acid (metaphosphate), pyrophosphoric acid (pyrophosphate), orthophosphoric acid (orthophosphate), triphosphoric acid (triphosphate), tetraphosphoric acid (tetraphosphate), hexametaphosphoric acid (hexametaphosphate), and so on are exemplified. As such an acid created from diphosphorus pentaoxide upon hydration or its salt used particularly preferably, orthophosphoric acid (orthophosphate), and hexametaphosphoric acid (hexametaphosphate) are exemplified, and more specifically, sodium orthophosphoric acid, sodium dihydrogen orthophosphoric acid, sodium hexametaphosphoric acid, ammonium hexametaphosphoric acid, and so on are exemplified. 
     The acid created from diphosphorus pentaoxide upon hydration or its salt used preferably in this invention is added to the image forming layer or a binder layer adjacent thereto because bringing desired effects even in a small amount. 
     The use amount (coating amount per ie of photosensitive material) of the acid created from diphosphorus pentaoxide upon hydration or its salt used in this invention can be a prescribed amount according to the performance such as the sensitivity or the fog, and a preferable use amount is 0.1 to 500 mg/m 2 , and more preferably, 0.5 to 100 mg/m 2 . 
     The heat-developable image-recording material of the present invention contains a reducing agent for organic silver salt. The reducing agent for organic silver salt may be any substance, preferably an organic substance, which reduces the silver ion to metal silver. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but a hindered phenol reducing agent is preferred. The reducing agent is preferably contained in an amount of from 5 to 50% by mol. more preferably from 10 to 40% by mol. per mol of silver on the surface having an image-forming layer. The layer to which the reducing agent is added may be any layer on the surface having an image-forming layer. In the case of adding the reducing agent to a layer other than the image-forming layer, the reducing agent is preferably used in a slightly large amount of from 10 to 50% by mol per mol of silver. The reducing agent may also be a so-called precursor which is derived to effectively exhibit the function only at the time of development. 
     For the heat-developable photosensitive material using an organic silver salt, reducing agents over a wide range are known and these are disclosed in JP-A-46-6074, JP-A-47-1238, JP-A-47-33621, JP-A-49-46427, JP-A-49-115540, JP-A-50-14334, JP-A-50-36110, JP-A—50-147711, JP-A-51-32632, JP-A-51-1023721, JP-A-51-32324, JP-A-51-51933, JP-A-52-84727, JP-A-55-108654, JP-A-56-146133, JP-A-57-82828, JP-A-57-82829, JP-A-6-3793, U.S. Pat. Nos. 3,667,9586, 3,679,426, 3,751,252, 3,751,255, 3,761,270, 3,782,949, 3,839,048, 3,928,686 and 5,464,738, German Patent No. 2,321,328, European Patent 692732 and the like. Examples thereof include amidoximes such as phenylamidoxime, 2-thienylamidoxime and p-phenoxyphenylamidoxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; combinations of an aliphatic carboxylic acid arylhydrazide with an ascorbic acid such as a combination of 2,2-bis(hydroxymethyl)propionyl-β-phenylhydrazine with an ascorbic acid; combinations of polyhydroxybenzene with hydroxylamine, reductone and/or hydrazine such as a combination of hydroquinone with bis(ethoxyethyl)hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine; hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and anilinehydroxamic acid; combinations of an azine with a sulfonamidophenol such as a combination of phenothiazine with 2,6-dichloro-4-benzenesulfonamidophenol; β-cyanophenylacetic acid derivatives such as ethyl-α-cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate; bis-β-naphthols such as 2,2-dihydroxy-1,1-binaphthyl, 6,6-dibromo-2,2-dihydroxy-1,1-binaphthyl and bis(2-hydroxy-1-naphthyl)methane; combinations of a bis-β-naphthol with a 1,3-dihydroxybenzene derivative (e.g., 2,4-dihydroxybenzophenone, 2,4-dihydroxyacetophenone); 5-pyrazolones such as 3-methyl-1-phenyl-5-pyrazolone; reductones such as dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidonehexose reductone; sulfonamidophenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,3-diones; chromans such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 1,4-dihydropyridines such as 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine; bisphenols such as bis(2-hydroxy-3-t-butyl-5-methylphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4-ethylidene-bis(2-t-butyl-6-methylphenol), 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane and 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane; ascorbic acid derivatives such as 1-ascorbyl palmitate and ascorbyl stearate; aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and a certain kind of indane-1,3-diones; and chromanols such as tocopherol. Particularly preferred reducing agents are bisphenols and chromanols. 
     The reducing agent of the present invention may be added in any form of a solution, powder and a solid microparticle dispersion. The solid microparticle dispersion is performed using a known pulverizing means (e.g., ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill). At the time of solid microparticle dispersion, a dispersion aid may also be used. 
     When an additive known as a “color toner” capable of improving the image is added, the optical density increases in some cases. Also, the color toner is advantageous in forming a black silver image depending on the case. The color toner is preferably contained on the surface having an image-forming layer in an amount of from 0.1 to 50% by mol. more preferably from 0.5 to 20% by mol. per mol of silver. The color toner may be a so-called precursor which is derived to effectively exhibit the function only at the time of development. 
     For the heat-developable photosensitive material using an organic silver salt, color toners over a wide range are known and these are disclosed in JP-A-46-6077, JP-A-47-10282, JP-A-49-5019, JP-A-49-5020, JP-A-49-91215, JP-A-49-91215, JP-A-50-2524, JP-A-50-32927, JP-A-50-67132, JP-A-50-67641, JP-A-50-114217, JP-A-51-3223, JP-A-51-27923, JP-A-52-14788, JP-A-52-99813, JP-A-53-1020, JP-A-53-76020, JP-A-54-156524, JP-A-54-156525, JP-A-61-183642, JP-A-4-56848, JP-B-49-10727, JP-B-54-20333, U.S. Pat. Nos. 3,080,254, 3,446,648, 3,782,941, 4,123,282 and 4,510,236, British Patent No. 1,380,795 and Belgian Patent No. 841910. Examples of the color toner include phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-ones and cyclic imides such as quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides such as N-hydroxy-1,8-naphthalimide; cobalt complexes such as cobalt hexaminetrifluoroacetate; mercaptanes such as 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N-(aminomethyl)aryldicarboxyimides such as N,N-(dimethylaminomethyl)phthalimide and N,N-(dimethylaminomethyl)naphthalene-2,3-dicarboxyimide; blocked pyrazoles, isothiuronium derivatives and a certain kind of photobleaching agents, such as N,N′-hexamethylenebis(1-carbamoyl-3,5-dimethylpyrazole), 1,8-(3,6-diazaoctane)bis(isothiuroniumtrifluoroacetate) and 2-(tribromomethylsulfonyl)benzothiazole; 3-ethyl-5-[(3-ethyl-2-benzothiazolinylidene)-1-methylethylidene]-2-thio-2,4-oxazolidinedione; phthalazinone, phthalazinone derivatives and metal salts thereof, such as 4-(1-naphthyl)phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone or 2,3-dihydro-1,4-phthalazinedione; combinations of phthalazinone with a phthalic acid derivative (e.g., phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic acid anhydride); phthalazine, phthalazine derivatives (e.g., 4-(1-naphthyl)phthalazine, 6-chlorophthalazinone, 5,7-dimethoxyphthalazine, 2,3-dihydrophthalazine) and metal salts thereof; combinations of a phthalazine and a phthalic acid derivative (e.g., phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic acid anhydride), quinazolinedione, benzoxazine and naphthoxazine derivatives; rhodium complexes which function not only as a color toner but also as a halide ion source for the formation of silver halide at the site, such as ammonium hexachlororhodate(III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate(III); inorganic peroxides and persulfates such as ammonium disulfide peroxide and hydrogen peroxide; benzoxazine-2,4-diones such as 1,3-benzoxazin-2,4-dione, 8-methyl-1,3-benzoxazin-2,4-dione, and 6-nitro-1,3-benzoxazin-2,4-dione; pyrimidines and asymmetric triazines such as 2,4-dihydroxpyrimidine and 2-hydroxy-4-aminopyrimidine; and azauracil and tetraazapentalene derivatives such as 3,6-dimercapto-1,4-diphenyl-1H,4H-2,3a,5,6a-tetraazapentalene and 1,4-di(o-chlorophenyl)-3,6-dimercapto-1H,4H-2,3a,5,6a-tetraazapentalene. 
     The color toner of the present invention may be added in any form of a solution, powder, solid microparticle dispersion and the like. The solid fine particle dispersion is performed using a known pulverization means (e.g., ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill). At the time of solid microparticle dispersion, a dispersion aid may also be used. 
     As a binder for this invention, polymer latexes as described below are preferably used. At least one layer among image forming layers containing the photosensitive silver halide of the heat-developable photosensitive material of the invention is preferably an image forming layer containing the following polymer latex at least 50% by weight of the entire binders. Hereinafter, this image forming layer is referred to as “an image forming layer of the invention,” and the polymer latex is referred to as “a polymer latex of the invention.” The polymer latex can be used not only for the image forming layer but also for the protection layer and the back layer. Particularly, when the heat-developable photosensitive material of the invention is used for the printing purpose in which size deviation is concerned, it is preferable to use the polymer latex in the protection layer and the back layer. However, “the polymer latex” herein indicates water-insoluble hydrophobic polymer as fine particles dispersed in a water-soluble dispersion medium. With respect to the dispersion state, the polymer may be emulsified in the dispersion medium, emulsion-polymerized or micell dispersed or the polymer may have a partially hydrophilic structure in the polymer molecule so that the molecular chain itself is dispersed in the molecule. The polymer latex for use in the present invention is described in Gosei Jushi Emulsion (Synthetic Resin Emulsion), compiled by Taira Okuda and Hiroshi Inagaki, issued by Kobunshi Kanko Kai (1978), Gosei Latex no Oyo (Application of Synthetic Latex), compiled by Takaaki Sugimura, Yasuo Kataoka, Souichi Suzuki and Keishi Kasahara, issued by Kobunshi Kanko Kai (1993), and Soichi Muroi, Gosei Latex no Kagaku (Chemistry of Synthetic Latex), Kobunshi Kanko Kai (1970) and the like. The dispersion particles preferably have an average particle size of from 1 to 50,000 nm, more preferably on the order of from 5 to 1,000 nm. The particle size distribution of the dispersed particles is not particularly limited, and the dispersed particles may have a broad particle size distribution or a monodisperse particle size distribution. 
     As the polymer latex used for the present invention, a so-called core/shell type latex may be used other than the normal polymer latex having a uniform structure. In this case, it is preferred in some cases that the core and the shell have different glass transition temperatures. 
     The polymer latex used as the binder in the present invention has a glass transition temperature (Tg) of which preferred range may be different among those for the protection layer, the back layer and the image-forming layer. In the image-forming layer, the glass transition temperature is preferably from −30° C. to 40° C., to promote the diffusion of the photographically useful materials during the heat development. In the protection layer and the back layer, the glass transition temperature is preferably 25° C. to 70° C. because the protection layer and the back layer are brought into contact with various instruments. 
     The polymer latex for use in the present invention preferably has a minimum film-forming temperature (MFT) of from −30 to 90° C., more preferably from 0 to 70° C. In order to control the minimum film-forming temperature, a film-forming aid may be added. The film-forming aid is also called a plasticizer and it is an organic compound (usually an organic solvent) capable of reducing the minimum film-forming temperature of the polymer latex. This organic compound is described in Souichi Muroi, Gosei Latex no Kagaku (Chemistry of Synthetic Latex), Kobunshi Kanko Kai (1970), ibid. 
     The polymer species of the polymer latex for use in the present invention may be of acrylic resin, vinyl acetate resin, polyester resin, polyurethane resin, rubber-based resin, vinyl chloride resin, vinylidene chloride resin, polyolefin resin or a copolymer thereof. The polymer may be a straight-chained polymer, a branched polymer or a cross-linked polymer. The polymer may be a so-called homopolymer obtained by polymerizing a single kind of monomers or may be a copolymer obtained by polymerizing two or more kinds of monomers. The copolymer may be either a random copolymer or a block copolymer. The polymer preferably has a number average molecular weight of from 5,000 to 1,000,000, more preferably on the order of from 10,000 to 100,000. If the molecular weight is too small, the image-forming layer is deficient in the mechanical strength, whereas if it is excessively large, the film-forming property is disadvantageously poor. 
     Specific examples of the polymer latex used as a binder in the image-forming layer of the heat-developable image-recording material of the present invention include a methyl methacrylate/ethyl acrylate/methacrylic acid copolymer latex, methyl methacrylate/2-ethylhexyl acrylate/hydroxyethyl methacrylate/styrene/acrylic acid copolymer latex, styrene/butadiene/acrylic acid copolymer latex, styrene/butadiene/divinylbenzene/methacrylic acid copolymer latex, methyl methacrylate/vinyl chloride/acrylic acid copolymer latex and vinylidene chloride/ethyl acrylate/acrylonitrile/methacrylic acid copolymer latex. Such polymers are also commercially available and examples of the polymer which can be used include acrylic resins such as CEBIAN A-4635, 46583, 4601 (all produced by Dicel Kagaku Kogyo Co., Ltd), Nipol Lx811, 814, 821, 820, 857, 857x2 (all produced by Nippon Zeon Co., Ltd); polyester resins such as FINETEX ES650, 611, 675, 850 (all produced by Dai-Nippon Ink &amp; Chemicals, Inc.), WD-size and WMS (both produced by Eastman Chemical); polyurethane resins such as HYDPAN AP10, 20, 30, 40 (all produced by Dai-Nippon Ink &amp; Chemicals, Inc.); rubber-based resins such as LACSTAR 7310K, 3307B, 4700H, 7132C (all produced by Dai-Nippon Ink &amp; Chemicals, Inc.), Nipol Lx416, 410, 438C, 2507 (all produced by Nippon Zeon Co., Ltd.); vinyl chloride resins such as G351, G576 (both produced by Nippon Zeon Co., Ltd.); vinylidene chloride resins such as L502, L513 (both produced by Asahi Chemical Industry Co., Ltd.), ARON D7020, D504, D5071 (all produced by Mitsui Petrochemical Industries, Ltd.); and olefin resins such as CHEMIPEARL S120 and SA100 (both produced by Mitsui Petrochemical Industries, Ltd.) and the like. These polymers may be used individually or if desired, as a blend of two or more thereof. 
     The image forming layer of the invention is preferably structured to include the polymer latex having 50% by weight of the entire binder, more preferably, 70% by weight. 
     The image forming layer of the invention may contain a hydrophilic polymer, if desired, in an amount of less than 50% by weight of the entire binder, such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and hydroxypropylmethyl cellulose. The amount of the hydrophilic polymer added is preferably 30% by weight or less of the entire binder in the image-forming layer, more preferably, 5% by weight. 
     The image forming layer of the present invention is preferably formed by coating an aqueous coating solution and then drying it. The term “aqueous” as used herein means that 60% by weight or more of the solvent (dispersion medium) in the coating solution is composed of water. The component other than water of the coating solution may be a water-miscible organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellusolve, ethyl cellusolve, dimethylformamide, and ethyl acetate. As a detailed solvent composition, the followings can be exemplified: water/methanol=90/10, water/methanol=70/30, water/ethanol=90/10, water/isopropanol=90/10, water/dimethylformamide=95/5, water / methanol/dimethylformamide=80/15/5, water/methanol/dimethylformamide=90/5/5 (the number indicates % by weight). 
     The total binder amount of the image forming layer of the invention is 0.2 to 30 g/m 2 , more preferably 1to 15 m 2 . A crosslinking agent for crosslinking and a surfactant for improving coating capability or the like can be added to the image forming layer of the invention. 
     The heat-developable image-recording material of the present invention may contain a sensitizing dye. The sensitizing dye may be any one of those that can spectrally sensitize the halogenated silver halide particles at a desired wavelength region when they are adsorbed on the halogenated silver halide particles. As such sensitizing dyes, usable are, for example, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonole dyes and hemioxonole dyes. Sensitizing dyes which are usable in the present invention are described, for example, in Research Disclosure, Item 17643, IV-A (December, 1978, page 23), Item 1831X (August, 1978, page 437) and also in the references as referred to in them. In particular, sensitizing dyes having a color sensitivity suitable for spectral characteristics of light sources of various laser imagers, scanners, image setters, process cameras and the like can advantageously be selected. 
     Exemplary dyes for spectral sensitization to so-called red light from light sources such as He-Ne laser, red semiconductor laser, and LED include Compounds I-1 to I-38 disclosed in JP-A-54-18726, Compounds I-1 to I-35 disclosed in JP-A-6-75322, Compounds I-1 to I-34 disclosed in JP-A-7-287338, Dyes 1 to 20 disclosed in JP-B-55-39818, Compounds I-1 to I-37 disclosed in JP-A-62-284343, and Compounds I-1 to I-34 disclosed in JP-A-7-287338. 
     Spectral sensitization as to the wavelength region of from 750 to 1,400 nm from semiconductor laser light sources can advantageously be obtained with various known dyes such as a cyanine dye, a merocyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye and a xanthene dye. Useful cyanine dyes are cyanine dyes having a basic nucleus such as thiazoline nucleus, oxazoline nucleus, pyrroline nucleus, pyridine nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus or imidazole nucleus. Useful merocyanine dyes are merocyanine dyes having the above-described basic nucleus or an acidic nucleus such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus or pyrazolone nucleus. Of these cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. The dye may be appropriately selected from known dyes described, for example, in U.S. Pat. Nos. 3,761,279, 3,719,495 and 3,877,943, British Patent Nos. 1, 466,201, 1,1469,117 and 1, 422,057, JP-B-3-10391, JP-B-6-52387, JP-A-5-341432, JP-A-6-194781 and JP-A-6-301141. 
     The dyes particularly preferably used for the present invention are cyanine dyes having a thioether bond (e.g., cyanine dyes described in JP-A-62-58239, JP-A-3-138638, JP-A-3-138642, JP-A-4-255840, JP-A-5-72659, JP-A-5-72661, JP-A-6-222491, JP-A-2-230506, JP-A-6-258757, JP-A-6-317868, JP-A-6-324425, JP-W-A-7-500926, and U.S. Pat. No. 5,541,054), dyes having a carboxylic acid group (e.g., dyes disclosed in JP-A-3-163440, JP-A-6-301141, and U.S. Pat. No. 5,441,899), merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes (dyes disclosed in JP-A-47-6329, JP-A-49-105524, JP-A-51-127719, JP-A-52-80829, JP-A-54-61517, JP-A-59-214846, JP-A-60-6750, JP-A-63-159841, JP-A-6-35109, JP-A-6-59381, JP-A-7-146537, JP-A-7-146537, JP-A-W-55-50111, British Patent No. 1,467,638, and U.S. Pat. No. 5,281,515) and the like. 
     Dyes forming i-band have been disclosed in U.S. Pat. Nos. 5,510,236, 3,871,887 (Example 5), JP-A-2-96131, JP-A-59-48753 and the like, and they can preferably be used for the present invention. 
     These sensitizing dyes may be used either individually or in combination of two or more thereof. The combination of sensitizing dyes is often used for the purpose of supersensitization. In combination with the sensitizing dye, a dye which itself has no spectral sensitization effect or a material which absorbs substantially no visible light, but which exhibits supersensitization may be incorporated into the emulsion. Useful sensitizing dyes, combinations of dyes which exhibit supersensitization, and materials which show supersensitization are described in  Research Disclosure,  Vol. 176, 17643, page 23, Item IV-J (December, 1978), JP-B-49-25500, JP-B-43-4933, JP-A-59-19032, JP-A-59-192242 and the like. 
     The sensitizing dyes may be used in combination of two or more of them for the present invention. The sensitizing dye may be added to the silver halide emulsion by dispersing it directly in the emulsion or may be added to the emulsion after dissolving it in a solvent such as water, methanol, ethanol, propanol, acetone, methyl cellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol and N,N- dimethylformamide, and the solvent may be a sole solvent or a mixed solvent. 
     Furthermore, the sensitizing dye may be added using a method disclosed in U.S. Pat. No. 3,469,987 where a dye is dissolved in a volatile organic solvent, the solution is dispersed in water or hydrophilic colloid, and the dispersion is added to an emulsion, a method disclosed in JP-B-44-23389, JP-B-44-27555 and JP-B-57-22091 where a dye is dissolved in an acid and the solution is added to an emulsion or the solution is formed into an aqueous solution while allowing the presence together of an acid or base and then added to an emulsion, a method disclosed in U.S. Pat. Nos. 3,822,135 and 4,006,025 where an aqueous solution or colloid dispersion of a dye is formed in the presence of a surface active agent and the solution or dispersion is added to an emulsion, a method disclosed in JP-A-53-102733 and JP-A-58-105141 where a dye is dissolved directly in hydrophilic colloid and the dispersion is added to an emulsion, or a method disclosed in JP-A-51-74624 where a dye is dissolved using a compound capable of red shifting and the solution is added to an emulsion. An ultrasonic wave may also be used in dissolving the dye. 
     The sensitizing dye for use in the present invention may be added to a silver halide emulsion for use in the present invention in any step heretofore known to be useful in the preparation of an emulsion. The sensitizing dye may be added in any time period or step before the coating of the emulsion, for example, in the grain formation process of silver halide and/or before desalting or during the desalting process and/or the time period from desalting until initiation of chemical ripening, as disclosed in U.S. Pat. Nos. 2,735,766, 3,628,960, 4,183,756 and 4,225,666, JP-A-58-184142 and JP-A-60-196749, or immediately before or during the chemical ripening process or in the time period after chemical ripening until coating, as disclosed in JP-A-58-113920. Furthermore, as disclosed in U.S. Pat. No. 4,225,666 and JP-A-58-7629, the same compound by itself may be added in parts or a compound in combination with another compound having a different structure may be added in parts, for example, one part is added during grain formation and another part is added during or after chemical ripening, or one part is added before or during chemical ripening and another part is added after completion of the chemical ripening, and when the compound is added in parts, the combination of the compound added in parts with another compound may also be changed. 
     The amount of the sensitizing dye used in the present invention may be selected according to the performance such as sensitivity or fog; however, it is preferably from 10 −6  to 1 mol. more preferably from 10 −4  to 10 −1  mol. per mol of silver halide in the photosensitive layer that is the image-forming layer. 
     The silver halide emulsion and/or organic silver salt for use in the present invention can be further prevented from the production of additional fog or stabilized against the reduction in sensitivity during the stock storage, by an antifoggant, a stabilizer or a stabilizer precursor. Examples of antifoggants, stabilizers and stabilizer precursors which can be appropriately used individually or in combination include thiazonium salts described in U.S. Pat. Nos. 2,131,038 and 2,694,716, azaindenes described in U.S. Pat. Nos. 2,886,437 and 2,444,605, mercury salts described in U.S. Pat. No. 2,728,663, urazoles described in U.S. Pat. No. 3,287,135, sulfocatechol described in U.S. Pat. No. 3,235,652, oximes, nitrons and nitroindazoles described in British Patent No. 623,448, polyvalent metal salts described in U.S. Pat. No. 2,839,405, thiuronium salts described in U.S. Pat. No. 3,220,839, palladium, platinum and gold salts described in U.S. Pat. Nos. 2,566,263 and 2,597,915, halogen-substituted organic compounds described in U.S. Pat. Nos. 4,108,665 and 4,442,202, triazines described in U.S. Pat. Nos. 4,128,557, 4,137,079, 4,138,365 and 4,459,350, and phosphorus compounds described in U.S. Pat. No. 4,411,985. 
     The antifoggant which is preferably used in the present invention is an organic halide, and examples thereof include the compounds described in JP-A-50-119624, JP-A-50-120328, JP-A-51-121332, JP-A-54-58022, JP-A-56-70543, JP-A-56-99335, JP-A-59-90842, JP-A-61-129642, JP-A-62-129845, JP-A-6-208191, JP-A-7-5621, JP-A-7-2781, JP-A-8-15809 and U.S. Pat. Nos. 5,340,712, 5,369,000 and 5,464,737. 
     The antifoggant for use in the present invention may be added in any form of a solution, powder, solid microparticle dispersion and the like. The solid microparticle dispersion is performed using a known pulverization means (e.g., ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill). At the time of solid microparticle dispersion, a dispersion aid may also be used. 
     Although not necessary for practicing the present invention, it is advantageous in some cases to add a mercury(II) salt as an antifoggant to the image-forming layer. Preferred mercury(II) salts for this purpose are mercury acetate and mercury bromide. The addition amount of mercury for use in the present invention is preferably from 1×10 −9  to 1×10 −3  mol. more preferably from 1×10 −8  to 1×10 −4  mol. per mol of silver coated. 
     The heat-developable image-recording material of the present invention may contain a benzoic acid compound for the purpose of achieving high sensitivity or preventing fog. The benzoic acid compound for use in the present invention may be any benzoic acid derivative, but preferred examples of the structure include the compounds described in U.S. Pat. Nos. 4,784,939 and 4,152,160 and JP-A-9-329863, JP-A-9-329864 and JP-A-9-281637. The benzoic acid compound for use in the present invention may be added to any site of the photosensitive material, but the layer to which the benzoic acid is added is preferably a layer on the surface having the image-forming layer such as a photosensitive layer, more preferably an organic silver salt-containing layer that is the image-forming layer. The benzoic acid compound for use in the present invention may be added at any step during the preparation of the coating solution. In the case of adding the benzoic acid compound to an organic silver salt-containing layer, it may be added at any step from the preparation of the organic silver salt until the preparation of the coating solution, but is preferably added in the period after the preparation of the organic silver salt and immediately before the coating. The benzoic acid compound for use in the present invention may be added in any form of a powder, solution, microparticle dispersion and the like, or may be added as a solution containing a mixture of the benzoic acid compound with other additives such as a sensitizing dye, a reducing agent and a color toner. The benzoic acid compound for use in the present invention may be added in any amount; however, the addition amount thereof is preferably from 1×10 −6 to 2 mol. more preferably from 1×10 −3  to 0.5 mol of silver. 
     The heat-developable image-recording material of the present invention may contain a mercapto compound, a disulfide compound or a thione compound so as to control the development by inhibiting or accelerating the development, improve the spectral sensitization efficiency or improve the storage stability before or after the development. 
     In the case of using a mercapto compound in the present invention, any structure may be used but those represented by AR—SM or Ar—S—S—Ar are preferred, wherein M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or condensed aromatic ring containing one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms, preferably a heteroaromatic ring such as benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline and quinazolinone. The heteroaromatic ring may have a substituent selected from, for example, the group consisting of halogen (e.g., Br, Cl), hydroxy, amino, carboxy, alkyl (e.g., alkyl having one or more carbon atoms, preferably from 1 to 4 carbon atoms), and alkoxy (e.g., alkoxy having one or more carbon atoms, preferably from 1 to 4 carbon atoms). Examples of the mercapto substituted heteroaromatic compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2,2′-dithiobis(benzothiazole), 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline, 8-mercaptopurine, 2-mercapto-4(3H)-quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 4-hydroxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-phenyloxazole and the like. However, the present invention is by no means limited thereto. 
     The amount of the mercapto compound added is preferably from 0.0001 to 1.0 mol. more preferably from 0.001 to 0.3 mol. per mol of silver in an emulsion layer. 
     The photosensitive layer such as a photosensitive layer for use in the present invention may contain a plasticizer or lubricant, and examples thereof include polyhydric alcohols (for example, glycerins and diols described in U.S. Pat. No. 2,960,404), fatty acids or esters described in U.S. Pat. Nos. 2,588,765 and 3,121,060, and silicone resins described in British Patent No. 955,061. 
     With this invention, it is preferable to form a protection layer on the image forming layer, and as a binder for such a protection layer, it is preferable to use a latex of a polymer having a glass transition temperature of 25° C. or higher and 70° C. or lower as described above. In this situation, it is preferable to use the above polymer latex to form 50% by weight or higher, preferably 70% by weight or higher, of the entire binder of the protection layer. In this invention, at least one layer of such a protection layer is preferably formed. The binder structure, coating method, and the like of such a protection layer are substantially the same as those of the image forming layer. Preferably used as the binder for the protective layer are those based on acrylic compound, styrene, acrylic compound/styrene, vinyl chloride, and vinylidene chloride. Specifically, those of acrylic resin type such as VONCORT R3370, 4280, Nipol Lx857, and methyl methacrylate/2-ethylhexyl (meta)acrylate/hydroxyethyl meth(meta)acrylate/styrene/(meta)acrylic acid copolymers; those of vinyl chloride resin type such as Nipol G576; and those of vinylidene chloride resin type such as Aron D5071 are preferably used. 
     The entire binder amount for protection layer used for the invention is 0.2 to 5.0 g/m 2 , more preferably, 0.5 to 4.0 g/m 2 . 
     As a surface protection layer of the invention, any adhering prevention material can be used. As an example for an adhering prevention material, exemplified are wax, silica particles, styrene containing elastomeric block copolymer (e.g., styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate, and mixtures of those are exemplified. A crosslinking agent for crosslinking and a surfactant for improving coating capability or the like can be added to the image forming layer of the invention. 
     For the image forming layer of the invention and the protection layer of the image forming layer, a light absorbing substance or a photographic element including a filter dye as described in U.S. Pat. No. 3,253,921, U.S. Pat. No. 2,274,782, U.S. Pat. No. 2,527,583, and U.S. Pat. No. 2,956,879 can be used. Moreover, the dye can be mordanted as described in U.S. Pat. No. 3,282,699. As the use amount of the filter dye, the light absorbing degree at the exposing wavelength is preferably 0.1 to 3, more preferably, 0.2 to 1.5. 
     The photosensitive layer that is the image-forming layer for use in the present invention may contain a dye or pigment of various types so as to improve the color tone or prevent the irradiation. Any dye or pigment may be used in the photosensitive layer for use in the present invention, and examples thereof include pigments and dyes described in the color index. Specific examples thereof include organic pigments and inorganic pigments such as a pyrazoloazole dye, an anthraquinone dye, an azo dye, an azomethine dye, an oxonol dye, a carbocyanine dye, a styryl dye, a triphenylmethane dye, an indoaniline dye, an indophenol dye and phthalocyanine. Preferred examples of the dye for use in the present invention include anthraquinone dyes (e.g., Compounds 1 to 9 described in JP-A-5-341441, Compounds 3-6 to 3-18 and 3-23 to 3-38 described in JP-A-5-165147), azomethine dyes (e.g., Compounds 17 to 47 described in JP-A-5-341441), indoaniline dyes (e.g., Compounds 11 to 19 described in JP-A-5-289227, Compound 47 described in JP-A-5-341441, Compounds 2-10 and 2-11 described in JP-A-5-165147) and azo dyes (Compounds 10 to 16 described in JP-A-5-341441) The dye may be added in any form of a solution, emulsified product or solid microparticle dispersion or may be added in the state mordanted with a polymer mordant. The amount of such a compound used may be determined according to the objective amount absorbed but, in general, the compound is preferably used in an amount of from 1×10 −6  to 1 g per square meter of the heat-developable image-recording material. 
     The heat-developable photographic photosensitive material according to the invention is preferably a so-called one side photosensitive material having a photosensitive layer containing at least one layer of silver halide emulsion on one side of the support, and a back layer on the other side. 
     With this invention, the back layer preferably has a maximum absorption in a prescribed range of about 0.3 or higher and 2.0 or lower. If the prescribed range is 750 to 1,400 nm, it is preferable that the optical density is equal to or greater than 0. 005 and less than 0.5 in a range of 750 to 360 nm, more preferably, that it is an antihalation layer having an optical density equal to or greater than 0.001 and less than 0.3. When the prescribed range is 750 rn or less, the antihalation layer preferably has a maximum absorption equal to or greater than 0.3 less than 2.0 before image forming in the prescribed range and an optical density equal to or greater than 0.001 and less than 0.3 after image forming in the range of 750 to 360 nm. There is no special limitation to a method for lowering the optical density down to the above range after forming images, and exemplified are a method lowering dye density by eliminating colors from heating as described in Belgian Patent No. 733,706, a method for lowering density by eliminating colors from light radiation as set forth in JP-A-54-17,833, and the like. 
     In the case when an antihalation dye is used in the present invention, the dye may be any compound so long as the compound has an objective absorption in the desired wavelength region, the absorption in the visible region can be sufficiently reduced after the processing, and the antihalation layer can have a preferred absorption spectrum form. While examples thereof include those described in the following patent publications, the present invention is by no means limited thereto: as a single dye, the compounds described in JP-A-59-56458, JP-A-2-216140, JP-A-7-13295, JP-A-7-11432, U.S. Pat. No. 5,380,635, JP-A-2-68539 (from page 13, left lower column, line 1 to page 14, left lower column, line 9) and JP-A-3-24539 (from page 14, left lower column to page 16, right lower column); and as a dye which is decolored after the processing, the compounds described in JP-A-52-139136, JP-A-53-132334, JP-A-56-501480, JP-A-57-16060, JP-A-57-68831, JP-A-57-101835, JP-A-59-182436, JP-A-7-36145, JP-A-7-199409, JP-B-48-33692, JP-A-B-50-16648, JP-B-2-41734 and U.S. Pat. Nos. 4,088,497, 4,283,487, 4,548,896 and 5,187,049. 
     In this invention, the suitable binder for back layer is transparent or semitransparent, and generally colorless and can be a natural polymer, synthetic resin polymer or copolymer, and other media for forming films, such as: gelatin, Arabic rubber, polyvinyl alcohol), hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, poly(vinylprrolidone), casein, starch, poly(acrylic acid), poly(methymethacrylic acid), poly(vinyl choride), poly(methacrylic acid), copoly(styrene-maleic anhydride), copoly(styrene-acrylonitrile), copoly(styrene-butadiene), poly(vinyl acetal) group such as poly(vinyl formal) and poly(vinyl butyral), poly (ester) group, poly(urethane) group, phenoxy resin, poly (vinylidene chloride), poly(epoxide), poly(carbonate) group, poly(vinyl acetate), cellulose ester group, poly(amide) group. The binder can be covered with water, organic solvent, or emulsion. 
     In the one side photosensitive material according to the invention, a matting agent can be added to a surface protection layer of a photosensitive emulsion layer and/or a back layer or a surface protection layer of a back layer to improve the conveyance property. The matting agent is fine particles of organic or inorganic compounds, which are generally water-insoluble. Arbitrary agents as a matting agent can be used, such as well-known in the art, e.g., organic matting agents described in specifications of U.S. Pat. No. 1,939,213, U.S. Pat. No. 2,701,245, U.S. Pat. No. 2,322,037, U.S. Pat. No. 3,262,782, U.S. Pat. No. 3,539,344, and U.S. Pat. No. 3,767,448, and inorganic agents described in specifications of U.S. Pat. No. 1,260,772, U.S. Pat. No. 2,192,241, U.S. Pat. No. 3,257,206 U.S. Pat. No. 3,370,951, U.S. Pat. No. 3,523,022, U.S. Pat. No. 3,769,020. For example, as examples of an organic compound that can be used as a matting agent, specifically, preferably used are: as a water-dispersing vinyl polymer, polymethylacrylate, polymethylmethacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene, polystyrene, styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, derivative, methylcellulose, cellulose acetate, cellulose acetate propionate, and the like, as a starch derivative, carboxystarch, carboxynitrophenylstarch, urea-formaldehyde-starch reactant, and the like, as hardened gelatin in use of a known hardening agent, and hardened gelatin of micro capsule hollow particles upon coacervation hardening. As examples of inorganic compounds, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, sliver chloride that is made less sensitive by a known method, silver bromide of the same, glass, and diatomite can be used preferably. The matting agent can be used according to the necessity in mixing substances of different kinds. There is no special limitation on the size and shape of the matting agent, and the agent of any grain size can be used. It is preferable to use the grain size of 0.1 micron to 30 microns when this invention is implemented. The grain size profile of the matting agent can be narrow and wide. On the other hand, because the matting agent greatly affects the haze and surface luster of the sensitive material, it is preferable to design the grain size, the shape, and the grain size profile meeting to the condition corresponding to the necessity at a time of production of the matting agent or by mixing of plural matting agents. 
     It is a preferable embodiment that the matting agent is added to the back layer in this invention, and as a mat degree of the back layer the Beck smoothness is preferably 1200 sec or less and 10 sec or more, and more preferably 700 sec or less and 50 sec or more. 
     In this invention, the matting agent is preferably contained in an outmost surface layer of the photosensitive material, a layer functioning as an outmost surface layer, and a layer closer to the external surface and preferably contained on a layer functioning as a so-called protection layer. The mat degree of the emulsion surface protection layer can be any one as far as the stardust problem does not occur, and it is preferable that the Beck smoothness is 500 sec or more and 10000 sec or less, and particularly, 500 sec or more and 2000 sec or less. 
     The heat-developable photographic emulsion used in this invention is structured of a single or more layers on the support. The structure of a single layer includes the organic silver salt, the silver halide, the developing agent, and the binder, and desired additional materials such as color adjuster, covering aid, and other aids. The structure of two layers includes the organic silver salt and the silver halide in the first emulsion layer (ordinarily a layer adjacent to the base), and some other components should be included in the second layer or both layers. However, a two layer structure is conceivable in which the entire components are contained in the sole emulsion layer and in which a protection layer is contained. The structure of multicolor photosensitive heat-developable photographic material may contain a component of those two layers for each color, and a single layer may contain all components as set forth in U.S. Pat. No. 4,708,928. In the case of multi-dye multicolor photosensitive heat-developable photographic material, each emulsion layer may held generally in being distinctive from one another by using functional or non-functional barrier layers between the respective photosensitive layers as set forth in U.S. Pat. No. 4,460,681. 
     A backside resistive heating layer described in U.S. Pat. Nos. 4,460,681 and 4,374,921 may also be used in the photosensitive heat-developable photographic image system. 
     A film hardening agent may be used for respective layers such as the photosensitive layer, the protection layer, and the back layer. As an example for the film hardening agent, exemplified are polyisocyanate groups as set forth in U.S. Pat. No. 4,281,060, JP-A-6-208,193, and the like, epoxy compound groups as set forth in U.S. Pat. No. 4,791,042 and the like, vinylsulfone based compound groups as set forth in JP-A-62-89048, and the like. 
     A surfactant can be used in this invention for improving the coating property, and the electrostatic property, and the like. As examples of the surfactant, any proper materials, such as nonion based, anion based, cation based, fluorine based and the like can be used. More specifically, exemplified are fluorine based polymer surfactants as set forth in JP-A-62-170,950, U.S. Pat. No. 5,380,644, and the like, fluorine based surfactants as set forth in JP-A-60-244,945, JP-A-63-188,135, and the like, polysiloxane based surfactants as set forth in U.S. Pat. No. 3,885,965, and the like, polyalkileneoxide as set forth in JP-A-6-301,140, anion based surfactants, and so on. 
     The photographic emulsion for heat-development of the invention can be generally covered on various kinds of support. Typical supports comprise polyester film, undercoating polyester film, poly(polyethylene terephthalate) film, polyethylene naphthalate film, cellulose nitrate film, cellulose ester film, poly(vinylacetal) film, polycarbonate film, and related or resin like materials, and include glass, paper, metal and so on. Also typically used are flexible supports, particularly, a paper support coated by a polymer such as partially acetified, or baryta and/or (x-olefin polymer, particularly, a-olefin polymer having the carbon number of 2 to 10 such as polyethylene, polypropylene, ethylene-butene copolymer, and the like. The support can be transparent or not transparent, but the preferable support is transparent. Among these, biaxially stretched polyethylene terephthalate to about 75 to 200 microns is preferred. 
     On the other hand, if a plastic film is passed through a heat developing apparatus for heat processing done at 80° C., the film generally is contracted in size. When the material after the processing is used for printing platemaking purpose, this contraction raises a serious problem when a precise multicolor printing is done. Therefore, in this invention, it is preferable to use a film having a small size change in which inner stresses remaining in the film are relaxed during biaxially stretching to eliminate thermal contraction stresses occurring during the heat development. For example, a polyethylene terephthalate film or the like can be used preferably which is thermally treated at a temperature of 100° C. to 210° C. before the photographic emulsion for heat development is coated. Also films having a higher glass transition temperature are preferable, and polyetherethyleketone, polystyrene, polysulfone, polyethersulfone, polyacrylate, polycarbonate, and the like can be used. 
     The heat-developable photosensitive material according to the invention may include a layer containing, e.g., soluble salts (e.g., choloride, nitrate, etc.), evaporated metal layer, ionic polymers as set forth in U.S. Pat. No. 2,861,056 and U.S. Pat. No. 3,206,312, insoluble inorganic salts as set forth in U.S. Pat. No. 3,428,451, tin oxide as set forth in JP-A-60-2S2,349, and JP-A-57-104,931, and so on. 
     As a method for obtaining color images using the heat-developable photosensitive materials of the invention, there is a method as set forth in JP-A-7-13,295, 10 page left column 43 line to 11 page left column line 40. As a stabilizer for color dying images, exemplified are British Pat. No. 1,326,889, U.S. Pat. No. 3,432,300, No. 3,698,909, No. 3,574,627, No. 3,573,050, No. 3,764,337, and No. 4,042,394. 
     The heat-developable photographic emulsion of the invention can be coated by various coating operations such as a dipping coating, a air knife coating, flow coating, and extrusion coating using a hopper as set forth in U.S. Pat. No. 2,681,294. Two or more layers, if desired, can be covered at the same time by a method as set forth in U.S. Pat. No. 2,761,791, and British Patent No. 837,095. 
     The heat-developable photographic material of the invention may contain additional layers, for example, a dye reception layer for receiving movable dye images, non-transparent layer used when a reverse printing is made, a protection top coating layer, primer layers already known in the art of light heat photographic technology, and so on. The sensitive material of the invention preferably can form images with the single sheet only, and it is preferable that the functional layers necessary for forming images such as an image receiving layer or the like are not in another sensitive material. 
     FIG. 1 shows a structural example off a heat developing machine used for heat developing process of the heat-developable photosensitive material of the invention. FIG. 1 shows a side view of the heat developing machine. The heat developing machine shown in FIG. 1 includes a feeding roller pair  11  (lower roller is the heating roller) for feeding the heat-developable photosensitive material  10  in a plane manner in correcting and preheating the material  10  into a heating section and another feeding roller pair  12  for feeding the heat-developable photosensitive material  10  in a plane manner in correcting the material  10  after heat development. The heat-developable photosensitive material  10  is subject to heat development during feeding from the feeding roller pair  11  to the feeding roller pair  12 . A conveying means for conveying the heat-developable photosensitive material  10  during the heat development has a plurality of rollers  13  on a side with which a surface having the image forming layer is in contact and a smooth surface  14  to which a nonwoven fabric (e.g., polyphenylene sulfate, Teflon) or the like is adhered on a side where the back surface in opposition to the above side is in contact. The heat-developable photosensitive material  10  is conveyed by drive of the plural rollers  13  in contact with the surface having the image forming layer where the back surface slides on the smooth surface  14 . As a heating means, heaters  15  are installed over the rollers  13  and below the smooth surface  14  so that the double sides of the heat-developable photosensitive material  10  is heated. As a heating means in this situation, panel heaters and the like are exemplified. The clearance between the rollers  13  and the smooth surface  14  may vary depending on the member of the smooth surface but is adjusted to a certain clearance capable of feeding the heat-developable photosensitive material  10 . It is preferably 0 to 1 mm. 
     The material of the surface of each roller  13  and the member of the smooth surface  14  can be any material as far as durable at a high temperature and not raising any problem to feed the heat-developable photosensitive material  10 . The material of the roller surface is preferably silicone rubber, and the member of the smooth surface is preferably of a nonwoven fabric made of a polyphenylenesulfate (PPS) or Teflon (PTFE). As a heating means, plural heaters are used, and each preferably is controlled to set freely its heating temperature. 
     A preheating portion on an upstream side of the heat-developable processing section can heat at a temperature lower than the heat developing temperature (e.g., about 10 to 20° C. lower) and higher than the glass transition temperature (Tg) of the support of the heat-developable photosensitive material  10 . It is desirable to set the portion as not to create unevenness in development. 
     A guide plate  16  is disposed on a downstream side of the heat developing processing section, and a slowly cooling section is also disposed. The guide plate is preferably made of a material having a low heat conducting rate, and cooling preferably is done gradually. 
     The machine is illustrated according to the illustrated example, but the heat developing machine is not limited to this, and the heat developing machine used in this invention can have various structures as set forth in,, e.g., JP-A-7-13,294. In the case of the multistage heating method used preferably in this invention, with the above apparatus or the like, two or more heat sources having different heating temperatures are installed, and they are heated at different temperatures continuously. 
     Hereinafter, the advantages of the invention are illustrated with the examples below, but this invention is not limited to those. 
     EXAMPLES 
     Example 1 
     (Preparation of Silver Halide Emulsion) 
     (Emulsion A) 
     Into 700 ml of water, 11 g of phthalized gelatin, 30 mg of potassium bromide and 10 mg of sodium benzene thiosulfonate were dissolved, and after adjusting the pH to 5.0 at a temperature of 40° C., 159 ml of an aqueous solution containing 18.6 g of silver nitrate and an aqueous solution containing 1 mol/l of potassium bromide, 5×10 −6  mol/l of (NH 4 ) 2 RhC 15 (H 2 O), and 2×10 −5  mol/l of K 3 IrC 16  were added by the control double jet method over 6 minutes and 30 seconds while keeping the pAg at 7.7. Subsequently, 476 ml of an aqueous solution containing 55.5 g of silver nitrate and an aqueous halogen salt solution containing 1 mol/l of potassium bromide and 2×10 −5  mol/l of K 3 IrC 16  were added by the control double jet method over 28 minutes and 30 seconds while keeping the pAg at 7.7. Thereafter, the pH was lowered to cause coagulation precipitation and then 0.17 g of Compound A and 23.7 g of deionized gelatin (calcium containing amount is 20 ppm) are adjusted to the pAg at 8.0 with the pH 5.9. The obtained particles had a mean particle size of 0.08 micron, a coefficient of variation of the projected area of 9%, and a (100) face ratio of 90% and were cubic particles. 
     The silver halide particles thus obtained was warmed to 60° C. and added with sodium benzene thiosulfonate in an amount of 76 micron mol per mol of silver, and after 3 minutes, sodium thiosulfate of 154 microns was added, ripened for 100, it was cooled to 40° C. after adding 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene of 5×10 −4  mol. 
     Subsequently, it was kept at 40° C., added with 12.8×10 −4  mol of the below sensitizing dye A and the compound B of 6.4×10 −3  mol in stirring those. After rapidly cooling it after 20 minutes, the preparation of silver halide emulsion A was finished.                    
     (Preparation of organic silver salt dispersion) 
     123 ml of 1N aqueous NAOH solution was added to 6.1 g of arachic acid, 37.6 g of behenic acid, and 70 ml of tert-butanol in 700 ml of distilled water with stirring at 75° C. allowed to react for one hour, and cooled to 65° C. Then, 112.5 ml of an aqueous solution containing 22 g of silver nitrate was added over 45 seconds to the reaction mixture, which was then left as it was for 5 minutes to be cooled to 30° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtered water became 30 μS/cm. The solid content obtained as described above was handled as a wet cake without being dried. Polyvinyl alcohol (goods name: PVA-217) of 7.5 g and water are added to the wet cake corresponding to 100 g of dried solid portion, and it was adjusted to be 500 g as the whole weight and then preliminarily dispersed at a homo mixer. 
     Then, the original liquid already preliminarily dispersed was treated three times where the pressure of the dispersing machine (goods name: Microfluidizer M-110S-EH, Microfluidics International Corporation made, with G10Z interaction chamber) is adjusted to 1750 kg /m 2  and handled three times to obtain the organic silver salt dispersion A. The organic acid silver salt particles contained in the organic acid silver salt dispersion obtained as described above were acicular grains having an average minor axis length of 0.04 μm, an average major axis length of 0.8 μm and a variation coefficient of 30%. The measure the particle size is made by Master Sizer X made of Malvern Instruments Ltd. The cooling control is made by attaching the meander type heat exchangers in the front of and at the rear of the interaction chamber, and the desired dispersion temperature was set by adjusting the temperature of the coolant. Thus, the organic silver salt A having 85 mol % of behenic acid containing rare was prepared. 
     (Preparation of solid fine particle dispersion of 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane) 
     To 20 g of 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane and 3.0 g of MP-203 of Kuray Co. made, 77 g of water was added and sufficiently stirred to form a slurry. The slurry was left for three hours. Subsequently, the slurry was introduced into a vessel together with 360 g of zirconia beads having an average particle size of 0.5 mm, and dispersed in a dispersing machine (1/4G Sand Grinder Mill, Imex Co., Ltd.) for 3 hours to prepare a reducing agent solid fine particle dispersion. The particle size was 0.3 micron or larger and 1.0 micron or less with 80% by weight of particles. 
     (Preparation of solid fine particle dispersion of tribromomethylphenylsulfone) 
     To 30 g of tribromomethylphenylsulfone, 0.5 g of hydroxypropylmethyl cellulose, and 0.5 g of a compound C 88.5 g of water were added and sufficiently stirred to form a slurry, which was left for three hours. Subsequently, in substantially the same manner as the reducing agent solid fine particle dispersion, a solid fine particle dispersion for prevention agent was prepared. The particle size was 0.3 micron or larger and 1.0 micron or less with 80% by weight of particles. 
     (Preparation of coating solution for emulsion layer) 
     To silver 1 mol of the thus produced organic silver salt fine particle dispersant, the following binders, materials, and a silver halide emulsion A are added, and adding water, an emulsion layer coating liquid was formed. 
     Binder; LACSTAR3307B as a solid portion, 406 g 
     (Dainippon Ink &amp; Chemicals, Inc., SBR latex, glass transition temperature Tg=17° C.) 
     1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5- 
                 119 
                 g 
               
               
                   
                 trimethylhexane as a solid portion 
               
               
                   
                 tribromomethylphenylsulfone 
                 21.6 
                 g 
               
               
                   
                 as a solid portion 
               
               
                   
                 sodium benzene thiosulfonate 
                 0.44 
                 g 
               
               
                   
                 benzotriazole 
                 1.25 
                 g 
               
               
                   
                 polyvinyl alcohol (MP-203 (Kuraray Co., Ltd)) 
                 20 
                 g 
               
               
                   
                 iso-propylephthalazin 
                 0.10 
                 mol 
               
               
                   
                 ortho-sodium dihydrogen phosphate 
                 0.13 
                 g 
               
               
                   
                 development suppressor A 
                 9.38 
                 g 
               
               
                   
                 nucleation agent 
               
               
                   
                   
               
            
           
         
       
     
     kinds and mounts as set forth in Table 23 
     dye A coating amount such that the optical density of 783 nonmagnetic is 0.3 
     silver halide emulsion A 0.05 mol as Ag amount                    
     (Preparation of coating solution for emulsion surface protection layer) 
     3.75 g of H 2 O was added to 102 g of a polymer latex of a copolymer of methyl methacrylate/styrene/2-ethylhexyl acrylate/2-hydroxyethyl methacrylate/acrylic acid=59/9/26/5/1 (wt %), (copolymer; glass transition temperature Tg; 54° C., solid concentration of 44%, compound D as film forming aid; 15 wt %), added successively with 30 wt % of carnauba wax (Chukyo Oil and Fat Co., Ltd. Cellosol 524), 0.188 g of Compound E, 2.55 g of Compound F. 0.56 q of a matting agent (polystyrene particles, mean particle size 7 microns), and 0.4g of polyvinyl alcohol, as well as H 2 O, thereby preparing the coating liquid. The pH of the coating liquid was 2.8.                    
     (Production of PET support having back layer/undercoating layer) 
     (1) Support 
     Using a terephthalic acid and an ethylene glycol, according to an normal method, a PET of IV (intrinsic viscosity)=66 (measured at 25° C. in phenol/ tetrachloroethane=6/4 (ratio by weight)) was obtained. After this was made into pellets, they are dried for four hours at 130° C. After extruded from a T-shape die after melted at 300° C., the material was rapidly cooled, and non-drawn film was produced with a thickness such that the film thickness after getting thermal stability was 120 microns. 
     This film was longitudinally drawn 3.3 times using rollers having different peripheral speeds from one another and transversely drawn 4.5 times using a tenter. At that time, the temperatures are 110° C. and 130° C., respectively. Then, 4% relaxation was made in the transverse direction at the temperature of 240° C. after thermally stabilizing the film at the same temperature for 20 seconds. Subsequently, the chuck of the tenter was released, the both edges of the film were knurled, and the film was rolled at 4.8 kg /cm 2 . Thus, a roll was obtained with a width of 2.4 m, a length of 3,500 m, and a thickness of 120 microns. 
     (2) Undercoating layer (a) 
     Polymer latex (1) 
     (styrene/butadiene/hydroxyethylmethacrylate/divinylbenzene=67/30/2.5/0.5 (% by weight), 160 g/m 2    
     2,4-Dichloro-6-hydroxy-s-triazine 4 mg/m 2    
     Matting agent (polystyrene, average diameter; 2.4 μm) 3 mg/m 2    
     (3) Undercoat layer (b) 
     Deionized gelatin 50 mg/m 2    
     (Ca ++  content; 30 ppm, jelly strength; 230 g) 
     (4) Electroconductive layer 
     Julimer ET-410(Nihon Junyaku Co., Ltd.) 38 mg/m 2    
     Alkali treated gelatin (molecular amount about 1,000, Ca ++  content; 30 ppm) 42 mg/m 2    
     Deionized gelatin(Ca ++  content; 0.6ppm) 8 mg/m 2    
     Compound A 0.2 mg/m 2    
     Polyoxyethylenephenylether 10 mg/m 2    
     Sumitex Resin M-3 
     (water-soluble melamine compound, Sumitomo Chemical Industry (K.K.) made) 
     Dye A coating amount making the optical density of 783 nm 1.2. SnO 2 /Sb (weight ratio; 9/1, needle shaped fine particles, major/minor axis=20 to 30, Isihara Sangyo K.K. made) 160 mg/m 2    
     Matting agent (Polymethyl methacrylate, average particle size; 5 μm) 7 mg/m 2    
     (5) Protection layer 
     Polymer latex (2) 
     (methyl methacrylate/styrene/2-ethylhexyl acrylate/2-hydroxyethyl methacrylate/acrylic acid=59/9/26/5/1 (wt %, copolymer)) 1000 mg/m 2    
     Polystyrenesulfonate (molecular weight) 2.6 mg/m 2    
     Cellosol 524 (Chukyo Oil and Fat Co., Ltd. ) 25 mg/m 2    
     Sumitex Resin M-3 
     (water-soluble melamine compound, Sumitomo Chemical Industry (K.K.) made) 218 mg/m 2    
     The undercoating layer (a) and the undercoating layer (b) were coated sequentially on one side of the support, and those were dried for four minutes at 180° C. Then, a conductive layer and a protection layer were coated sequentially on the opposite side to the side where the undercoating layer (a) and the undercoating layer (b) were coated, and a PET support was produced with back/undercoating layers upon drying at 180° C. for 30 seconds. 
     Thus formed PET support with the back/undercoating layers was placed in thermal treatment zone extending in a whole length of 30 m set at a temperature of 150° C., and conveyed by its weight at a tension of 14 g/cm 2  and feeding speed of 20 m/min. Thereafter, it passed a zone of 40° C. for 15 seconds, and was wound by winding tension of 10 kg/cm 2 .                    
     (Preparation of the heat developable photosensitive material) 
     The above emulsion coating liquid was coated as to make the coated sliver amount 1.7 g/m 2  on the undercoating layer of the PET support on a side where the undercoating layer (a) and the undercoating layer (b) were coated. The emulsion surface protection coating liquid is coated simultaneously together with the emulsion coating liquid so that the coating amount of the polymer latex was 3.0 g/m 2 . 
     (Evaluation of photographic ability) 
     (Exposing processing) 
     The obtained heat-developable photosensitive material was exposed for 2×10 −8  using a laser exposing apparatus of a single channel cylindrical inner surface type on which a semiconductor laser is mounted with beam diameter (FWHM, a half of beam intensity) of 12.56 microns, laser output of 50 mW, and output wavelength of 783 nm in adjusting the exposure time by changing the mirror rotary number and the exposure amount by changing the the output value. The overlap coefficient (FWHM/Pitch width of a subsanning) at that time was as shown in Table 23. 
     (Heat development processing) 
     The exposed heat-developable photosensitive material was subject to a heat development processing using the heat developing machine as shown in FIG. 1 for 20 seconds at a temperature of 120° C. at the thermal development processing section as well as a temperature of 90 to 100° C. for five seconds at the preliminary heating section where the roller surface material was a silicon rubber and where the smooth surface was a PPS nonwoven fabric at the heat development processing section. The temperature accuracy in the transverse direction was +1° C. 
     (Evaluation of Photographic Performance) 
     The obtained images were evaluated using a Macbeth TD904 densitometer (visible density, dot %). The results were evaluated by Dmin, Dmax, sensitivity (inverse of ratio of exposure amount giving a higher density by 1.0 than Dmin), γ (contrast) and change of dot %. The γ was expressed by the gradient of a straight line connecting points of densities 0.2 and 2.5 with each other, where the logarithm of the exposure amount was abscissa. The change of the dot % was expressed from deviations from 5% dot and 95% dot in regard with how each dot changed upon the heat development processing by outputs of 5% and 95% dots at the exposing amount where the laser output amount was adjusted to produce 50% flat dots during the exposing processing and the heat development processing. The smaller deviation indicates good reproducing capability of dot images. 
     The results that the above evaluations were made are shown in Table 23 with respect to each heat-developable photosensitive materials. 
     
       
         
           
               
               
               
               
               
               
               
               
               
            
               
                   
               
               
                 Heat Developable 
                 Nucleation 
                 Nucleation 
                   
                   
                   
                   
                   
                   
               
               
                 Photosensitive Material 
                 Agent 
                 Agent Adding 
                 Subscanning 
                 Overlap 
                   
                   
                 γ 
                 Change of Dot % 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 No. 
                 Species 
                 Amount (mol) 
                 Pitch (μm) 
                 Coefficient 
                 Dmin 
                 Dmax 
                 Contrast 
                 Dot 5% 
                 Dot 95% 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                  1 
                 C-62 
                 3 × 10 −2   
                 112  
                 0.112 
                 0.13 
                 2.7 
                 3.5 
                 Unable to 
                 Unable to 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                 Evaluate due 
                 Evaluate due to 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                 to Raster 
                 Raster 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                 Unevenness 
                 Unevenness 
               
               
                  2 This Invention 
                 C-62 
                 3 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 4.1 
                 8 
                 0 
                 0 
               
               
                  3 This Invention 
                 C-62 
                 3 × 10 −2   
                 35 
                 0.359 
                 0.13 
                 4.3 
                 10 
                 0 
                 0 
               
               
                  4 This Invention 
                 C-62 
                 3 × 10 −2   
                 28 
                 0.449 
                 0.13 
                 4.5 
                 10 
                 0 
                 +1% 
               
               
                  5 This Invention 
                 C-62 
                 4.5 × 10 −2   
                 56 
                 0.224 
                 0.14 
                 4.5 
                 13 
                 −1% 
                 +1% 
               
               
                  6 
                 C-62 
                 6 × 10 −2   
                 56 
                 0.224 
                 0.16 
                 4.5 
                 20 
                 −5% (No Dot to 
                 +3% 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                 be Put) 
               
               
                  7 This Invention 
                 C-62 
                 1.5 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 3.5 
                 5 
                 +1% 
                 −1% 
               
               
                  8 
                 — 
                 — 
                 56 
                 0.224 
                 0.12 
                 1.6 
                 Unable 
                 Unable to 
                 Unable to 
               
               
                   
                   
                   
                   
                   
                   
                   
                 to 
                 Evaluate due 
                 Evaluate due to 
               
               
                   
                   
                   
                   
                   
                   
                   
                 evaluate 
                 to Low Density 
                 Low Density 
               
               
                  9 This Invention 
                 54a 
                 1 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 4.2 
                 10 
                 0 
                 0 
               
               
                 10 This Invention 
                 54a 
                 1 × 10 −2   
                 56 
                 0.359 
                 0.13 
                 4.4 
                 11 
                 0 
                 +1% 
               
               
                 11 This Invention 
                 C-1  
                 1 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 4.1 
                 8 
                 0 
                 0 
               
               
                 12 This Invention 
                 C-42 
                 1 × 10 −2   
                 56 
                 0.224 
                 0.12 
                 3.9 
                 6 
                 −1% 
                 0 
               
               
                 13 This Invention 
                 C-8  
                 1 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 4 
                 8 
                 −1% 
                 0 
               
               
                 14 This Invention 
                 C-57 
                 1 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 4.1 
                 8 
                 0 
                 0 
               
               
                 15 This Invention 
                 C-64 
                 1 × 10 −2   
                 56 
                 0.224 
                 0.13 
                 4 
                 7 
                 0 
                 0 
               
               
                   
               
            
           
         
       
     
     According to the image forming method using the heat-developable photosensitive material of the invention, it is turned out that good performance such as a high Dmax and good reproductivity of dotted images is obtained.