Image forming method using heat-developable photosensitive material

An image forming method using heat-developable photosensitive material includes, 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 heats, 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.sup.-7 second, and wherein the .gamma. of the heat-developable photosensitive material after the step of developing the images with heat (wherein the .gamma. 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.ltoreq..gamma..ltoreq.15. According to the method, obtainable images are capable of being exposed rapidly, with a high Dmax (maximum density) and reduced dot shifts during the heat development process.

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.degree. 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.sup.-7 second, and wherein the .gamma. of the heat-developable
 photosensitive material after the step of developing the images with heat
 (wherein the .gamma. 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.ltoreq..gamma..ltoreq.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.degree. C. or higher and 40.degree. 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.degree. C. or higher and 40.degree. 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.degree. C. or higher and 70.degree. 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),
 ##STR1##
 In the formula (1), R.sup.1, R.sup.2 and R.sup.3 each independently
 represents a hydrogen atom or a substituent, Z represents an electron
 withdrawing group or a silyl group, and R.sup.1 and Z, R.sup.2 and
 R.sup.3, R.sup.1 and R.sup.2, or R.sup.3 and Z may be combined with each
 other to form a ring structure; in the formula (2), R.sup.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.

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.degree. C., more preferably from 100 to 140.degree. 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.degree. C. or higher
 and 140.degree. C. or less after so heating five seconds or longer at a
 temperature of 80.degree. C. or higher and less than 115.degree. 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.degree. 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.degree. 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.sub.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.sup.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.sup.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.sup.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.degree. 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.degree. C. by
 such a cooling process, more preferably, in range of 5 to 80.degree. C.,
 and further 5 to 60.degree. 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.sup.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.degree. C.
 or a cool water of 5 to 10.degree. C. processed in a refrigerator, or a
 coolant of ethylene glycol and water of -30.degree. 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.sup.2, more preferably, 1
 to 3 g/m.sup.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.sup.-3 to 10.sup.-1 mol per one mol
 of the non-photosensitive organic silver salt, and more preferably,
 5.times.10.sup.-3 to 5.times.10.sup.-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 .mu.m or less, more
 preferably from 0.01 to 0.15 .mu.m, still more preferably from 0.02 to
 0.12 .mu.m. 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.times.10.sup.-9 to 1.times.10.sup.-2 mol, more preferably from
 1.times.10.sup.-8 to 1.times.10.sup.-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.times.10.sup.-8 to 5.times.10.sup.-6 mol. more preferably from
 5.times.10.sup.-8 to 1.times.10.sup.-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:
EQU [ML.sub.6 ].sup.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.sub.6 ].sup.3- [ReBr.sub.6 ].sup.3- [ReCl.sub.5 (NO)].sup.2-
 [Re(NS)Br.sub.5 ].sup.2- [Re(NO) (CN).sub.5 ].sup.2- [Re(O).sub.2
 (CN).sub.4 ].sup.3-
 [RuCl.sub.6 ].sup.3- [RuCl.sub.4 (H.sub.2 O).sub.2 ].sup.-
 [RuCl.sub.5 (H.sub.2 O) ].sup.2-
 [RuCl.sub.5 (NO)].sup.2- [RuBr.sub.5 (NS)].sup.2-
 [Ru(CO).sub.3 Cl.sub.3 ].sup.2- [Ru(CO)Cl.sub.5 ].sup.2-
 [Ru(CO)Br.sub.5 ].sup.2-
 [OsCl.sub.6 ].sup.3- [OsCl.sub.5 (NO)].sup.2- [Os(NO) (CN).sub.5
 ].sup.2-
 [Os(NS)Br.sub.5 ].sup.2- [Os(O).sub.2 (CN).sub.4 ].sup.4-
 The addition amount of these compound is preferably from 1.times.10.sup.-9
 to 1.times.10.sup.-5 mol. more preferably from 1.times.10.sup.-8 to
 1.times.10.sup.-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.times.10.sup.-9 to 1.times.10.sup.-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.sup.-7 mol or higher and 10.sup.-3
 mol or lower per one mol of the silver halide, and more preferably, it is
 10.sup.-6 mol or higher and 5.times.10.sup.-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.degree. 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.sup.-7 to 10.sup.-2 mol. more preferably from 10.sup.-5 to
 10.sup.-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.degree. 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.dbd.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.sup.-8 to 10.sup.-2
 mol. preferably on the order of from 10.sup.-7 to 10.sup.-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.degree. C., preferably from 45 to 85.degree.
 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.sup.-7 Mol to about 10.sup.-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 .gamma. (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.
 ##STR2##
 In the general formula (1) R.sup.1, R.sup.2 and R.sup.3 each independently
 represents a hydrogen atom or a substituent, Z represents an election
 withdrawing group or a silyl group, and R.sup.1 and Z, R.sup.2 and
 R.sup.3, R.sup.1 and R.sup.2, or R.sup.3 and Z may be combined with each
 other to form a ring structure; in the formula (2), R.sub.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.sup.1, R.sup.2 and R.sup.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.sup.1 and Z,
 R.sup.2 and R.sup.3, R.sup.1 and R.sup.2, or R.sup.3 and Z may be combined
 with each other to form a ring structure.
 When R.sup.1, R.sup.2 or R.sup.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's substituent constant .sigma.p 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.sup.1, R.sup.2 or R.sup.3 in the formula (1) may have.
 In the formula (1), R.sup.1 and Z, R.sup.2 and R.sup.3, R.sup.1 and
 R.sup.2, or R.sup.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.sup.1, R.sup.2 or R.sup.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.sup.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.sup.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.sup.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.sup.1 is more preferably an electron withdrawing
 group or an aryl group.
 The substituent represented by R.sup.2 or R.sup.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.sup.2 and R.sup.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.sup.2 and
 R.sup.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.sup.1
 represents an electron withdrawing group or an aryl group, and one of
 R.sup.2 and R.sup.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.sup.1 form a non-aromatic
 5-, 6- or 7-membered ring structure and one of R.sup.2 and R.sup.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.sup.1 is
 preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a
 thiocarbonyl group or a sulfonyl group and R.sup.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.sup.4 represents a substituent. Examples of the
 substituent represented by R.sup.4 include those described for the
 substituent represented by R.sup.1, R.sup.2 or R.sup.3 in the formula (1).
 The substituent represented by R.sup.4 is preferably an electron
 withdrawing group or an aryl group. When R.sup.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.sup.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.sup.1, R.sup.2 or R.sup.3
 in the formula (1).
 R.sup.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.sup.1,
 R.sup.2 or R.sup.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.sub.2).sub.2 --O--, --O--(CH.sub.2).sub.3 --O--,
 --S--(CH.sub.2).sub.2 --S--, --S--(CH.sub.2).sub.3 --S--, --S--ph--S--,
 --N(CH.sub.3)--(CH.sub.2).sub.2 --O--, --N(CH.sub.3)--(CH.sub.2).sub.2
 --S--, --O--(CH.sub.2).sub.2 --S--, --O--(CH.sub.2).sub.3 --S--, --N
 (CH.sub.3)--ph--O--, --N(CH.sub.3)--ph--S-- and --N(ph)--(CH.sub.2).sub.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.
 ##STR3##
 ##STR4##
 ##STR5##
 ##STR6##
 ##STR7##
 ##STR8##
 ##STR9##
 ##STR10##
 ##STR11##
 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.times.10.sup.-6
 to 1 mol. more preferably from 1.times.10.sup.-5 to 5.times.10.sup.-1 mol.
 most preferably from 2.times.10.sup.-5 to 2.times.10.sup.-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):
 ##STR12##
 In the formula, R represents an aliphatic group, an aromatic group or a
 heterocyclic group, R.sup.11 represents a hydrogen atom or a block group,
 G.sup.1 represents --CO--, --COCO--, --C(.dbd.S)--, --SO.sub.2 --, --SO--,
 --PO(R.sup.3)-- (wherein R.sup.13 is a group selected from the groups
 within the range defined for R.sup.11, and R.sup.13 may be different from
 R.sup.11), or an iminomethylene group, A.sup.1 and A.sup.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.sup.1 represents 0 or 1 and when m.sup.1 is 0, R.sup.1
 represents an aliphatic group, an aromatic group or a heterocyclic group.
 In the formula (H), the aliphatic group represented by R.sup.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.sup.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.sup.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.sup.12 is preferably an aryl group or an alkyl group.
 R.sup.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.sup.12 represents an aromatic group or a heterocyclic group, the
 substituent of R.sup.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.sup.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.sup.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.sup.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.sup.11 may be substituted, and examples of the
 substituent include those described as the substituent of R.sup.12.
 In the formula (H), R.sup.11 may be one which cleaves the G.sup.1
 --R.sup.11 moiety from the residual molecule and causes a cyclization
 reaction to form a cyclic structure containing the atoms in the --G.sup.1
 --R.sup.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.sup.11 or R.sup.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.sup.11 or R.sup.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.sup.11 or R.sup.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.sup.1 and A.sup.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'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'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.sup.1 and A.sup.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.sup.12 is preferably a phenyl group or a substituted alkyl group having
 from 1 to 3 carbon atoms.
 When R.sup.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.sup.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.sup.1 --R.sup.11).
 When R.sup.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.sup.12 represents a substituted methyl group, R.sup.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.sup.12 is most preferably a substituted phenyl group.
 In the formula (H), m.sup.1 represents 1 or 0. When m.sup.1 is 0, R.sup.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.sup.12.
 m.sup.1 is preferably 1.
 The preferred embodiment of the group represented by R.sup.11 is described
 below. When R.sup.12 is a phenyl group and G.sup.1 is --CO-- group,
 R.sup.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.sup.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.sup.12 is a substituted methyl group and G.sup.1 is --CO-- group,
 R.sup.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.sup.1 is --COCO-- group,
 R.sup.11 is preferably, irrespective of R.sup.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.sup.1 is --SO.sub.2 -- group, R.sup.11 is preferably, irrespective
 of R.sup.12, an alkyl group, an aryl group or a substituted amino group.
 In the formula (H), G.sup.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 =
 Y = --H
 --CF.sub.2 SCH.sub.3 --CONHCH.sub.3
 ##STR58##
 36
 ##STR59##
 36a 36o
 36p 36q
 37 2-OCH.sub.3 -
 37a 37o 37p 37q
 4-NHSO.sub.2 C.sub.12 H.sub.25
 38 3-NHCOC.sub.11 H.sub.23 -
 38a 38o 38p 38q
 4-NHSO.sub.2 CF.sub.3
 39
 ##STR60##
 39a 39o
 39p 39q
 40 4-OCO(CH.sub.2).sub.2 COOC.sub.6 H.sub.13
 40a 40o 40p 40q
 41
 ##STR61##
 41a 41o
 41p 41q
 42
 ##STR62##
 42a 42o
 42p 42q
 43
 ##STR63##
 44
 ##STR64##
 45
 ##STR65##
 46
 ##STR66##
 47
 ##STR67##
 48
 ##STR68##
 49
 ##STR69##
 50
 ##STR70##
 51
 ##STR71##
 52
 ##STR72##
 53
 ##STR73##
 ##STR74##
 R =
 Y = --H --CH.sub.2 OCH.sub.3
 ##STR75##
 --CONHC.sub.3 H.sub.7
 54 2-OCH.sub.3 54a 54m
 54r 54s
 55 2-OCH.sub.3 55a 55m
 55r 55s
 5-C.sub.8 H.sub.17 (t)
 56 4-NO.sub.2 56a 56m
 56r 56s
 57 4-CH.sub.3 57a 57m
 57r 57s
 58
 ##STR76##
 58a 58m
 58r 58s
 59
 ##STR77##
 59a 59m
 59r 59s
 ##STR78##
 R =
 Y = --H
 ##STR79##
 ##STR80##
 ##STR81##
 60 2-OCH.sub.3 60a 60c
 60f 60g
 5-OCH.sub.3
 61 4-C.sub.8 H.sub.17 (t) 61a 61c
 61f 61g
 62 4-OCH.sub.3 62a 62c
 62f 62g
 63 3-NO.sub.2 63a 63c
 63f 63g
 64
 ##STR82##
 64a 64c
 64f 64g
 65
 ##STR83##
 65a 65c
 65f 65g
 ##STR84##
 R.sub.B =
 R.sub.A = --H
 ##STR85##
 ##STR86##
 ##STR87##
 66
 ##STR88##
 66a 66u
 66v 66t
 67
 ##STR89##
 67a 67u
 67v 67t
 68
 ##STR90##
 68a 68u
 68v 68t
 69
 ##STR91##
 69a 69u
 69v 69t
 70
 ##STR92##
 70a 70u
 70v 70t
 71
 ##STR93##
 71a 71u
 71v 71t
 ##STR94##
 R.sub.B =
 R.sub.A =
 ##STR95##
 ##STR96##
 --OC.sub.4 H.sub.9 (t)
 ##STR97##
 72
 ##STR98##
 72s 72x
 72y 72w
 73
 ##STR99##
 73s 73x
 73y 73w
 74
 ##STR100##
 74s 74x
 74y 74w
 75
 ##STR101##
 75s 75x
 75y 75w
 76
 ##STR102##
 76s 76x
 76y 76w
 ##STR103##
 R =
 77
 ##STR104##
 78
 ##STR105##
 79 --CH.sub.2 OCH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 OCH.sub.3
 80 --CF.sub.2 CF.sub.2 COOH
 81
 ##STR106##
 82
 ##STR107##
 83
 ##STR108##
 84
 ##STR109##
 85
 ##STR110##
 86
 ##STR111##
 87
 ##STR112##
 88
 ##STR113##
 89
 ##STR114##
 90
 ##STR115##
 91
 ##STR116##
 92
 ##STR117##
 93
 ##STR118##
 94
 ##STR119##
 ##STR120##
 R =
 Y =
 ##STR121##
 ##STR122##
 ##STR123##
 --CH.sub.2 --Cl
 95
 ##STR124##
 95-1 95-2
 95-3 95-4
 96 4-COOH 96-1
 96-2 96-3 96-4
 97
 ##STR125##
 97-1 97-2
 97-3 97-4
 98
 ##STR126##
 98-1 98-2
 98-3 98-4
 99
 ##STR127##
 99-1 99-2
 99-3 99-4
 100
 ##STR128##
 100-1 100-2
 100-3 100-4
 ##STR129##
 X =
 Y =
 ##STR130##
 ##STR131##
 ##STR132##
 ##STR133##
 101 4-NO.sub.2 101-5
 101-6 101-7 101y
 102 2,4-OCH.sub.3 102-5
 102-6 102-7 102y
 103
 ##STR134##
 103-5 103-6
 103-7 103y
 X =
 Y =
 ##STR135##
 ##STR136##
 ##STR137##
 ##STR138##
 104
 ##STR139##
 104-8 104-9
 104w' 104x
 105
 ##STR140##
 105-8 105-9
 105w' 105x
 Y--NH NH--X
 X =
 Y =
 ##STR141##
 ##STR142##
 ##STR143##
 ##STR144##
 106
 ##STR145##
 106-10 106a
 106m 106y
 107
 ##STR146##
 107-10 107a
 107m 107y
 108
 ##STR147##
 108-10 108a
 108m 108y
 109
 ##STR148##
 109-10 109a
 109m 109y
 110
 ##STR149##
 110-10 110a
 110m 110y
 111
 ##STR150##
 111-10 111a
 111m 111y
 Y--NH NH--X
 X =
 Y =
 ##STR151##
 ##STR152##
 ##STR153##
 ##STR154##
 112
 ##STR155##
 112-11 112-12
 112-13 112-14
 113
 ##STR156##
 113-11 113-12
 113-13 113-14
 114
 ##STR157##
 114-11 114-12
 114-13 114-14
 115
 ##STR158##
 115-11 115-12
 115-13 115-14
 116
 ##STR159##
 116-11 116-12
 116-13 116-14
 117
 ##STR160##
 117-11 117-12
 117-13 117-14
 118
 ##STR161##
 119
 ##STR162##
 120
 ##STR163##
 121
 ##STR164##
 122
 ##STR165##
 123
 ##STR166##
 ##STR167##
 X =
 Ar = --OH --SH
 --NHCOCF.sub.3 --NHSO.sub.2 CH.sub.3 --NHSO.sub.2 ph
 --N(CH.sub.3).sub.2
 124
 ##STR168##
 124a 124b 124c
 124d 124e 124f
 125
 ##STR169##
 125a 125b 125c
 125d 125e 125f
 126
 ##STR170##
 126a 126b 126c
 126d 126e 126f
 127
 ##STR171##
 127a 127b 127c
 127d 127e 127f
 128
 ##STR172##
 128a 128b 128c
 128d 128e 128f
 129
 ##STR173##
 129a 129b 129c
 129d 129e 129f
 130
 ##STR174##
 130a 130b 130c
 130d 130e 130f
 131
 ##STR175##
 131a 131b 131c
 131d 131e 131f
 132
 ##STR176##
 132a 132b 132c
 132d 132e 132f
 133
 ##STR177##
 133a 133b 133c
 133d 133e 133f
 134
 ##STR178##
 134a 134b 134c
 134d 134e 134f
 135
 ##STR179##
 136
 ##STR180##
 137
 ##STR181##
 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.times.10.sup.-6 to 1.times.10.sup.-2 mol.
 more preferably from 1.times.10.sup.-5 to 5.times.10.sup.-3 mol. most
 preferably from 2-10.sup.-5 to 5.times.10.sup.-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.sup.2, and more preferably, 0.5 to 100 mg/m.sup.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-.beta.-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;
 .beta.-cyanophenylacetic acid derivatives such as
 ethyl-.alpha.-cyano-2-methylphenylacetate and
 ethyl-.alpha.-cyanophenylacetate; bis-.beta.-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-.beta.-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.degree. C. to 40.degree. 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.degree. C. to 70.degree. 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.degree. C., more
 preferably from 0 to 70.degree. 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 &
 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 & Chemicals, Inc.); rubber-based resins such as LACSTAR
 7310K, 3307B, 4700H, 7132C (all produced by Dai-Nippon Ink & 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.sup.2, more preferably 1to 15 m.sup.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.sup.-6 to 1 mol. more preferably from 10.sup.-4
 to 10.sup.-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.times.10.sup.-9 to
 1.times.10.sup.-3 mol. more preferably from 1.times.10.sup.-8 to
 1.times.10.sup.-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.times.10.sup.-6 to 2 mol. more preferably from
 1.times.10.sup.-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.degree. C. or higher and 70.degree. 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.sup.2, more preferably, 0.5 to 4.0 g/m.sup.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.times.10.sup.-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-.alpha.-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.degree. 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.degree. C. to 210.degree. 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.degree. 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.degree. 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.times.10.sup.-6 mol/l
 of (NH.sub.4).sub.2 RhC.sub.15 (H.sub.2 O), and 2.times.10.sup.-5 mol/l of
 K.sub.3 IrC.sub.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.times.10.sup.-5 mol/l of K.sub.3 IrC.sub.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.degree. 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.degree. C. after adding
 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene of 5.times.10.sup.-4 mol.
 Subsequently, it was kept at 40.degree. C., added with 12.8.times.10.sup.-4
 mol of the below sensitizing dye A and the compound B of
 6.4.times.10.sup.-3 mol in stirring those. After rapidly cooling it after
 20 minutes, the preparation of silver halide emulsion A was finished.
 ##STR182##
 (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.degree. C. allowed to react for one hour, and cooled
 to 65.degree. 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.degree. 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 .mu.S/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.sup.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 .mu.m, an average major axis length of
 0.8 .mu.m 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 & Chemicals, Inc., SBR latex, glass transition temperature
 Tg=17.degree. 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
 ##STR183##
 (Preparation of coating solution for emulsion surface protection layer)
 3.75 g of H.sub.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.degree. 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.sub.2 O, thereby preparing the coating liquid. The pH of the coating
 liquid was 2.8.
 ##STR184##
 (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.degree. 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.degree. C.
 After extruded from a T-shape die after melted at 300.degree. 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.degree. C. and
 130.degree. C., respectively. Then, 4% relaxation was made in the
 transverse direction at the temperature of 240.degree. 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.sup.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.sup.2
 2,4-Dichloro-6-hydroxy-s-triazine 4 mg/m.sup.2
 Matting agent (polystyrene, average diameter; 2.4 .mu.m) 3 mg/m.sup.2
 (3) Undercoat layer (b)
 Deionized gelatin 50 mg/m.sup.2
 (Ca.sup.++ content; 30 ppm, jelly strength; 230 g)
 (4) Electroconductive layer
 Julimer ET-410(Nihon Junyaku Co., Ltd.) 38 mg/m.sup.2
 Alkali treated gelatin (molecular amount about 1,000, Ca.sup.++ content; 30
 ppm) 42 mg/m.sup.2
 Deionized gelatin(Ca.sup.++ content; 0.6ppm) 8 mg/m.sup.2
 Compound A 0.2 mg/m.sup.2
 Polyoxyethylenephenylether 10 mg/m.sup.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.sub.2
 /Sb (weight ratio; 9/1, needle shaped fine particles, major/minor axis=20
 to 30, Isihara Sangyo K.K. made) 160 mg/m.sup.2
 Matting agent (Polymethyl methacrylate, average particle size; 5 .mu.m) 7
 mg/m.sup.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.sup.2
 Polystyrenesulfonate (molecular weight) 2.6 mg/m.sup.2
 Cellosol 524 (Chukyo Oil and Fat Co., Ltd. ) 25 mg/m.sup.2
 Sumitex Resin M-3
 (water-soluble melamine compound, Sumitomo Chemical Industry (K.K.) made)
 218 mg/m.sup.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.degree. 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.degree. 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.degree. C., and conveyed by its weight at a tension of
 14 g/cm.sup.2 and feeding speed of 20 m/min. Thereafter, it passed a zone
 of 40.degree. C. for 15 seconds, and was wound by winding tension of 10
 kg/cm.sup.2.
 ##STR185##
 (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.sup.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.sup.2.
 (Evaluation of photographic ability)
 (Exposing processing)
 The obtained heat-developable photosensitive material was exposed for
 2.times.10.sup.-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.degree. C. at the thermal
 development processing section as well as a temperature of 90 to
 100.degree. 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.degree. 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), .gamma. (contrast) and change of dot %. The .gamma. 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.

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