Post-activation type dry image forming material

A novel heat-activatable and heat-developable dry image forming material comprising (a) a silver salt of long chain fatty acid with at least 16 carbon atoms, (b) a reducing agent for silver ions, (c) a silver halide component including silver iodide or a silver halide-forming component including silver iodide-forming compound, (d) an oxidizing agent for free silver, (e) a photoreactive halogeno oxidizing agent, (f) a binder, and (g) a specific spectral sensitizing dye has been found to have improved spectral sensitivity as well as excellent storage stability.

This invention relates to a dry image forming material. More particularly, 
the present invention relates to a post-activation type dry image forming 
material which is nonphotosensitive under normal lighting conditions but 
is rendered so photosensitive by preliminary heating (heat activation) as 
to be capable of recording thereon a latent image and therefore, after 
activation, can form thereon a visible image by only a dry process 
comprising the step of image-wise exposure to light and the step of heat 
development, and which is improved in spectral sensitivity without being 
spoiled in such properties characteristic of imaging materials of 
post-activation type as capability of being stored even in a light room 
before image formation. If a raw image forming material which is not yet 
subjected to image formation can be stored even in a light room like a raw 
dry image forming material according to the present invention, it is 
possible that, after information is recorded in the form of an image on a 
desired area of the image forming material, new information can be 
recorded in the form of an additional image on another desired area of the 
image forming material at some convenient time. As desired, a copy of the 
material having the first information can be obtained by means of a 
copying machine such as a duplicator or a printer. It is needless to say 
that updated information can be recorded in the form of a further image on 
still another desired area of the image forming material as far as the 
image forming material has blank areas in which it is not yet subjected to 
image formation. Since the dry image forming material of the present 
invention is increased in spectral sensitivity, it can form thereon an 
image by photographing even a manuscript having a colored background or a 
colored image. Despite the increased sensitivity, the image forming 
material of the present invention is so stable as to enable additional 
information to be recorded thereon in a practical sense. 
As silver salt photographic materials on which an image can be formed by a 
dry process only, there have heretofore been proposed dry image forming 
materials comprising an organic silver salt oxidizing agent, a reducing 
agent for silver ions and a catalytic amount of a silver halide. Examples 
of such dry image forming materials include post-activation type dry image 
forming materials disclosed in U.S. Pat. Nos. 3,802,888 and 3,764,329, and 
Japanese Patent Publication Nos. 41967/1978 and 5685/1979, wherein the 
incorporation of a spectral sensitizing dye into a dry image forming 
material is mentioned. These proposed post-activation type dry image 
forming materials, however, are defective either in that they are so poor 
in light or storage stability of the raw image forming materials as to 
undergo marked deterioration in their photographic or sensitometric 
characteristics when stored under normal lighting conditions or when 
exposed to high temperatures even if stored in the dark, or in that they 
are too insufficient in sensitivity to be used in photographing. As the 
storage stability of a raw image forming material is increased, the 
sensitivity of the material is decreased, whereas the storage stability of 
a raw image forming material is decreased as the sensitivity of the 
material is increased. Therefore, none of the conventional post-activation 
type dry image forming materials are so good in both stability and 
sensitivity as to meet such a demand that the materials record thereon 
necessary information and even additional information in the form of 
visible images at desired places and times by a time-saving dry process 
only. 
It is, therefore, an object of the present invention to provide a 
practically usable post-activation type dry image forming material 
excellent enough in both stability and sensitivity to meet the 
above-mentioned demand and capable of recording thereon additional 
information. 
It is well known to those skilled in the art that it is very difficult to 
apply the knowledge and technique acquired and the various additives used 
in the field of wet process silver halide photographic materials to the 
field of dry process photographic or image-forming materials comprising as 
the essential components an organic silver salt oxidizing agent, a 
reducing agent for silver ions and a silver halide catalyst because both 
types of the materials are quite different in components and mechanism of 
image formation. It is particularly noted that post-activation type dry 
image forming materials, which are required to be capable of being exposed 
to or stored under normal lighting conditions substantially without 
undergoing deterioration in their photographic or sensitometric 
characteristics, are quite different in conditions of storage and image 
formation from the wet process photographic materials and even common 
heat-developable dry image forming materials of the already photosensitive 
type which are never exposed to light prior to use in image formation. 
Therefore, it is quite impossible to anticipate whether or not an additive 
suitable for the wet process photographic materials or the common dry 
image forming material of the already photosensitive type can be used 
successfully in post-activation type dry image forming materials. In fact, 
it is rather natural that such an additive be unable to be used in a 
post-activation type dry image forming material since incorporation of the 
additive into the post-activation type dry image forming material quite 
often results in low light or storage stability of the raw dry image 
forming material. For example, as is disclosed in Japanese Pat. 
Publication No. 25498/1974 and U.S. Pat. No. 3,933,507, incorporation of a 
spectral sensitizing dye into a system comprising an organic silver salt 
oxidizing agent and a reducing agent for silver ions but no photosensitive 
silver halide results in a dry image forming material of the already 
photosensitive type. As will be easily understood from this instance, a 
spectral sensitizing dye incorporated into an image forming system has a 
tendency to impart photosensitivity to the system. Accordingly, in the 
case of a post-activation type dry image forming material which is 
required to be capable of being exposed to light prior to use and of being 
preliminarily heated prior to image-wise exposure to light substantially 
without deterioration of its photographic or sensitometric characteristics 
and not to undergo substantial fogging, a spectral sensitizing dye, if 
incorporated into the material, generally downgrades drastically the light 
or storage stability of the raw image forming material and renders the 
material more subject to fogging. 
On the other hand, in the case of wet process silver halide photographic 
materials and common heat-developable dry image forming materials of the 
already photosensitive type, spectral sensitizing dyes as commonly used in 
these materials are not necessarily required to be stable to light 
irradiation and heating since the materials are never exposed to light and 
heat prior to use for image formation. In fact, unstable spectral 
sensitizing dyes are widely used in the above-mentioned materials. 
Almost all of the attempts to use in post-activation type dry image forming 
materials spectral sensitizing dyes as commonly used in the wet process 
silver halide photographic materials and the common heat-developable dry 
image forming materials of the already photosensitive type have failed 
either because the spectral sensitizing dyes adversely affects the 
stability of the resulting raw post-activation type dry image forming 
materials so that they cause the resulting dry image forming materials to 
undergo fogging at the step of preliminary heating prior to light exposure 
and the escalation of the fogging at the step of heat development, or 
because the spectral sensitizing dyes themselves are so decomposed or 
bleached in the post-activation type dry image forming materials as not to 
exhibit any spectrally sensitizing capability from the outset, or as to 
lose their spectrally sensitizing capability too rapidly to be practically 
useful. 
It is, therefore, another object of the present invention to provide a 
post-activation type dry image forming material of the character as 
described before, which is spectrally sensitized, but neither 
substantially undergoes such fogging caused by light irradiation or 
heating prior to use for image formation as will be attributable to the 
inclusion of a spectral sensitizing dye, nor involves any substantial loss 
of the spectrally sensitizing capability of a spectral sensitizing dye 
owing to the decomposition or bleaching of the spectral sensitizing dye.

We have made extensive and intensive investigations with a view to 
developing a post-activation type dry image forming material spectrally 
sensitized in a practical sense and having high sensitivity as well as 
excellent light or storage stability of raw material to find that such a 
post-activation type dry image forming material can be obtained when it 
includes peculiar oxidizing compounds [components (d) and (e) mentioned 
below] capable of providing a strongly oxidizing atmosphere unlike those 
in the case of wet process silver halide photographic materials and common 
heat-developable dry image forming materials of the already photosensitive 
type, and a specific spectral sensitizing dye having a unique chemical 
structure. We have completed the invention based on such a finding. 
More specifically, in accordance with the present invention, there is 
provided a post-activation type dry image forming material comprising: 
(a) a silver salt of long chain fatty acid having 16 or more carbon atoms; 
(b) a reducing agent for silver ions; 
(c) a silver halide component including silver iodide or a silver 
halide-forming component capable of forming a silver halide component 
including silver iodide by the reaction thereof with said silver salt of 
long chain fatty acid (a); 
(d) an oxidizing agent for free silver; 
(e) a photoreactive halogeno oxidizing agent; 
(f) a binder; and 
(g) a spectral sensitizing dye consisting of at least one member selected 
from the group consisting of those compounds represented by the following 
formulae: 
##STR1## 
wherein each Z independently is sulfur or selenium, Y is hydrogen or 
methyl, each R independently is hydrogen or chlorine, and M is hydrogen, 
HN(C.sub.2 H.sub.5).sub.3 or sodium. 
The post-activation type dry image forming material of the present 
invention is improved in stability of the material prior to heat 
activation, i.e., stability of the raw image forming material, as well as 
sensitivity. The reason for this is believed to be as follows. In the 
post-activation type dry image forming material, the silver halide 
component present therein as the component (c) prior to heat activation of 
the material is photochemically reduced by the action of light during the 
storage of the raw image forming material in a light room to form free 
silver in part in the silver halide crystals. The free silver thus formed, 
if left as it is, would exert a catalytic activity for promoting the 
reduction reaction of the silver salt of long chain fatty acid (a) capable 
of making a visual change. However, the free silver is oxidized by the 
action of the free silver-oxidizing agent (d) to reconvert the free silver 
into the original silver halide, leading to extinguishment of the 
above-mentioned catalytic activity to be exerted by the free silver. The 
free silver-oxidizing agent (d) having served to oxidize the free silver 
to the silver halide, itself, is in a reduced state. The reduced free 
silver-oxidizing agent (d), in turn, is oxidized by the photochemical 
action of the photoreactive halogeno oxidizing agent (e) so that it is 
returned to the original state to regenerate the capacity of oxidizing 
free silver. As is clearly understood from the foregoing explanation, a 
main reason for the excellent stability of the raw image forming material 
(material prior to heat activation) is believed to be that the component 
(d) reduced by having served to reconvert the light-produced free silver 
into the silver halide component is regenerated (oxidized) by the action 
of the component (e) during the course of storage. 
Silver iodide is superior in thermal stability to silver bromide and silver 
chloride. Further, the free silver formed in silver iodide crystals has a 
low redox potential and therefore is easily oxidized as compared with 
those produced in silver bromide crystals and silver chloride crystals. 
Accordingly, the inclusion of silver iodide in the silver halide component 
(c) enables the free silver photochemically produced in part in silver 
halide crystals to be easily oxidation-reconverted into the original 
silver halide by the action of the free silver-oxidizing agent (d). Both 
of the above-mentioned low redox potential of the free silver formed in 
silver iodide crystals and the thermal stability of silver iodide 
contribute to excellent stability of the raw material of the present image 
forming material containing silver iodide. 
Under a strongly oxidizing atmosphere provided in the post-activation type 
dry image forming material of the present invention, those compounds of 
the formula (I), (II), (III) or (IV) usable as the spectral sensitizing 
dye (g) do not act in favor of imparting a photosensitivity to the 
material, which also contributes, together with the high stability of the 
compounds themselves, to excellent stability of the raw material. 
It is needless to say that an light- or heat-unstable silver source for 
silver image formation is unsuitable for use in the post-activation type 
dry image forming material of the present invention. For instance, when a 
silver complex of imidazole, pyrazole, urazol, 1,2,4-triazole or 
1H-tetrazole, or a silver salt of lower fatty acid is used in place of the 
silver salt of long chain fatty acid (a), the resulting dry image forming 
material is unsatisfactory in stability of the raw material. 
As the silver salt of long chain fatty acid (a) having 16 or more carbon 
atoms to be used in the post-activation type dry image forming material of 
the present invention, there can be mentioned, for example, silver 
palmitate, silver margarate, silver stearate, silver arachidate, silver 
behenate, silver cerotate and silver melissinate. Silver behenate is most 
useful. They may be used either alone or in combination. The silver salt 
of long chain fatty acid may be used in an amount of about 0.1 to about 50 
g/m.sup.2, preferably 1 to 10 g/m.sup.2 of the support area of the present 
image forming material. 
As the reducing agent for silver ions (b) to be used in the post-activation 
type dry image forming material of the present invention, there is used an 
organic reducing agent which has a suitable reducing ability that, when 
heated, it reduces the non-photosensitive long chain fatty acid silver 
salt (a) with the aid of catalysis of the free silver produced in the 
exposed portions of the activated dry image forming material to form a 
visible silver image. Examples of the silver ion-reducing agents include 
monohydroxybenzenes such as p-phenylphenol, p-methoxyphenol, 
2,6-di-tert-butyl-4-methylphenol and 2,5-di-tert-4-methoxyphenol; 
polyhydroxybenzenes such as hydroquinone, tert-butylhydroquinone, 
2,6-dimethylhydroquinone, chlorohydroquinone and catechol; naphthols such 
as .alpha.-naphthol, .beta.-naphthol, 4-aminonaphthol and 
4-methoxynaphthol; hydroxybinaphthyls such as 
1,1'-dihydroxy-2,2'-binaphthyl and 
4,4'-dimethoxy-1,1'-dihydroxy-2,2'-binaphthyl; phenylenediamines such as 
p-phenylenediamine and N,N'-dimethyl-p-phenylenediamine; aminophenols such 
as N-methyl-p-aminophenol and 2,4-diaminophenol; sulfonamidophenols such 
as p-(toluenesulfonamido)phenol and 
2,6-dibromo-4-(p-toluenesulfonamido)phenol; methylenebisphenols such as 
2,2'-methylenebis(4-methyl-6-tert-butylphenol), 
2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 
2,2'-methylenebis[4-methyl-6-(1-methylcyclohexyl)phenol], 
1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane and 
2,6-bis(2'-hydroxy-3'-tert-butyl-5'-methylbenzyl)-4-methylphenol; 
3-pyrazolidones such as 1-phenyl-3-pyrazolidone and 
4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone; and ascorbic acids. A 
suitable reducing agent may be chosen depending on the kind of silver salt 
of long chain fatty acid (a) employed in combination therewith. Preferred 
are phenols. More preferred are hindered phenols in which one or two 
sterically bulky groups are bonded to the carbon atom or carbon atoms 
contiquous to the hydroxyl group-bonded carbon atom to sterically hinder 
the hydroxyl group. Such hindered phenols have a high stability to light 
and, hence, the use thereof is effective for assuring a high storage 
stability of the raw dry image forming material of the post-activation 
type. As examples of such hindered phenols, there can be mentioned 
2,6-di-tert-butyl-4-methylphenol, 
2,2'-methylenebis(4-methyl-6-tert-butylphenol), 
2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 
2,4,4-trimethylpentylbis(2-hydroxy-3,5-dimethylphenyl)methane (i.e., 
1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane), 
2,6-methylenebis-(2-hydroxy-3-tert-butyl-5-methylphenyl)-4-methylphenol, 
2,2'-methylenebis[4-methyl-6-(1-methylcyclohexyl)phenol] and 
2,5-di-tert-butyl-4-methoxyphenol. These reducing agents may be used 
either alone or in combination. The suitable amount of the reducing agent 
is usually in the range of from 0.1 to 3 moles per mol of the silver salt 
of long chain fatty acid (a). 
It is requisite for the purpose of the present invention that the silver 
halide component (c) or the silver halide component formed from the silver 
halide-forming component (c) include therein silver iodide. In order for 
the silver iodide to exert a sufficient effect for the purpose, it is 
preferable that silver iodide be included in an amount of at least 30 mole 
% based on the silver halide component. The more preferable amount of 
silver iodide is at least 50 mole % based on the silver halide component. 
From the viewpoint of sensitivity of the image forming material, the 
silver halide component is desired to contain, besides silver iodide, at 
least 2 mole %, based on the silver halide component, of silver bromide 
and/or silver chloride, although the silver halide component may include 
only silver iodide, i.e. 100 mole % of silver iodide. Furthermore, from 
the viewpoint of stability of the raw image forming material, it is 
desirable that the silver halide component contain, besides silver iodide, 
silver bromide rather than silver chloride. Therefore, the most preferred 
silver halide component consists of silver iodide and silver bromide. In 
this case, silver iodide and silver bromide may be provided in the form of 
either a mixture thereof or mixed crystals thereof. The molar ratio of 
silver iodide to silver bromide may be preferably 30/70 to 98/2, more 
preferably 50/50 to 95/5. The preferred amount of the silver halide 
component to be used is 0.1 to 20 mole %, based on the amount of the 
silver salt of long chain fatty acid (a). 
Silver iodide and any other silver halide(s) as prepared by the known 
method commonly employed in the field of photograhic film manufacture may 
be formulated as the silver halide component (c), together with other 
components such as the silver salt of long chain fatty acid, into a 
composition for providing the image forming coating or layer of the dry 
image forming material, as is disclosed in U.S. Pat. No. 3,152,904. 
Alternatively, silver iodide and any other silver halide(s) can be 
prepared in situ either in a composition for providing the image forming 
coating of the dry image forming material or in the coated image forming 
layer of the dry image forming material, by the reaction of a silver 
halide-forming component (c) with part of the long chain fatty acid silver 
salt (a), as is disclosed in U.S. Pat. No. 3,457,075. The latter mode is 
preferred in which silver iodide and any other silver halide(s) are formed 
by the reaction between the long chain fatty acid silver salt (a) and the 
silver halide-forming component (c), which is a kind of halogenating 
agent. 
As the suitable halogenating agent to be used as the silver halide-forming 
component (c) in the latter mode mentioned above, there can be mentioned 
organic halides of elements belonging to Group IV, V or VI of the periodic 
table and having an atomic number of 14 or more, the preferred elements 
being Ge, Sn, P, Bi, Te and Se, (see U.S. Pat. No. 4,113,496); halogen 
molecular species and complexes thereof (see U.S. Pat. No. 4,173,482); 
organic N-haloamides containing a unit of the formula -CONX- wherein X is 
bromine or iodine (see U.S. Pat. No. 3,764,329); aryl-halomethanes (see 
U.S. Pat. No. 4,188,266); and metal halides. They may be used either alone 
or in combination. Preferred are halogen molecular species and complexes 
thereof, and organic N-haloamides, from the viewpoint of stability of the 
raw image forming material. Specific examples of the halogenating agent 
include compounds respectively represented by the formulae: 
##STR2## 
In the above formulae, X is bromine or iodine. Further specific examples 
of the halogenating agent include iodine, bromine, iodine bromide, a 
complex of triphenyl phosphite and iodine, a complex of p-dioxane and 
iodine, a complex of p-dioxane and bromine, N-bromo(or -iodo)phthalimide, 
N-bromo(or -iodo)succinimide, N-bromo(or -iodo)phthalazinone, N-bromo(or 
-iodo)acetamide, N-bromo(or -iodo)acetanilide and .alpha.-bromo(or 
-iodo)diphenylmethane. Still further specific examples of the halogenating 
agent include CoX.sub.2, NiX.sub.2, MgX.sub.2, BaX.sub.2, RbX, CsX, 
TeX.sub.2, TeX.sub.4 and AsX.sub.3. In these formulae, X is bromine or 
iodine. From the viewpoint of stability of the raw image forming material 
as well as sensitivity, the preferred halogenating agents for forming 
silver iodide are iodine and N-iodosuccinimide. Complexes of iodine such 
as a complex of triphenyl phosphite and iodine and a complex of p-dioxane 
and iodine are also preferred. In the case of N-iodosuccinimide, it is 
preferred that a solution of N-iodosuccinimide in an alcohol such as 
methanol or ethanol, which has been previously prepared, be incorporated 
into an emulsion for the desired dry image forming material. From the 
viewpoint of sensitivity as well as stability of the raw image forming 
material, the preferred halogenating agents for forming silver bromide are 
N-bromosuccinimide, cobalt dibromide, nickel dibromide and 
.alpha.-bromodiphenylmethane. The amount, in equivalents, of the 
halogenating agent to be used may be equal to or more than the desired 
amount, in equivalents, of the silver halide component. 
The oxidizing agent for free silver (d) to be used in the post-activation 
type dry image forming material of the present invention has a capacity of 
oxidizing free silver produced during the storage of the material, thereby 
contributing to improving the stability of the raw material. As examples 
of the free silver-oxidizing agent (d), there can be mentioned compounds 
of divalent mercury (Hg.sup.++), compounds of trivalent iron (Fe.sup.+++), 
compounds of trivalent cobalt (Co.sup.+++), compounds of divalent 
palladium (Pd.sup.++) and sulfinic acid compounds. As examples of the 
compounds of divalent mercury, there can be mentioned mercuric salts of 
aliphatic carboxylic acids such as mercuric acetate and mercuric behenate; 
mercuric salts of aromatic carboxylic acids such as mercuric benzoate, 
mercuric m-methylbenzoate and mercuric acetamidobenzoate; mercuric halides 
such as mercuric bromide and mercuric iodide; mercuri-benzotriazole; and 
mercuri-phthalazinone. Preferred are mercuric acetate, mercuric bromide 
and mercuric iodide. As examples of the compounds of trivalent iron, there 
can be mentioned a complex of trivalent iron and acetylacetone and a 
complex of trivalent iron and bipyridyl. As examples of the compounds of 
trivalent cobalt, there can be mentioned a complex of trivalent cobalt and 
acetylacetone and a complex of trivalent cobalt and o-phenanthroline, and 
cobaltic halides such as cobaltic iodide and cobaltic bromide. Examples of 
the compounds of divalent palladium include a complex of divalent 
palladium and acetylacetone, and palladium (II) halides such as palladium 
(II) iodide and palladium (II) bromide. As examples of the sulfinic acid 
compound, there can be mentioned n-octylsulfinic acid and 
p-toluenesulfinic acid. As the component (d), the compounds of divalent 
mercury are most preferred. The preferred amount of the component (d) is 
in the range of from 0.01 to 10 mole % based on the silver salt of long 
chain fatty acid. 
As described before, the oxidizing agent for free silver [component (d)] is 
reduced by serving to oxidize the free silver produced during the storage 
of the raw image forming material into the original silver halide. The 
thus reduced oxidizing agent for free silver, in turn, is oxidized, under 
lighting conditions, by the action of the photoreactive halogeno oxidizing 
agent (e), whereby it is effectively returned to the original state in 
which the component (d) has a capacity of oxidizing free silver. The 
photoreactive halogeno oxidizing agent is such a halogeno compounds as can 
generate free radicals of halogen upon light exposure. Preferred examples 
of such a halogeno compound are halogenated organic compounds having 
bromine- and/or iodine-carbon linkages. 
Whether or not a given halogeno compound is suitable for use as the 
component (e) in the present invention can be determined, for example, by 
the following photoreaction test. 
1 Mole of silver behenate [suitable as the silver behenate is one which has 
been synthesized in a mixed solvent (1:5-5:1 by volume) of water and at 
least one water-soluble or partially water-soluble alcohol having 3 to 8 
carbon atoms], 450 g of polyvinyl butyral and 0.25 mole of said given 
halogeno compound for use as the "photoreactive halogeno oxidizing agent" 
are dissolved into a mixed solvent (2:1 by weight) of methyl ethyl ketone 
and toluene, and then formed into a film according to an ordinary casting 
method. 
The film thus formed is tested with respect to the following two 
requirements. When the film satisfies both of the requirements, the 
halogeno compound (for use as the photoreactive oxidizing agent) employed 
is suitable for the purpose of the present invention. 
Requirement 1: when the film is examined by X-ray diffractometry, the peak 
due to silver bromide (2.theta.=31.0.degree.) or the peak due to silver 
iodide (2.theta.=23.7.degree.) should not substantially be observed [the 
relative intensity of said peak is less than about 10 when the relative 
intensity of the peak due to silver behenate (2.theta.=12.1.degree.) is 
defined as 100]. 
Requirement 2: subsequently, the film is irradiated with a light (0.5 
mW/cm.sup.2) emitted from a black lamp in an atmosphere having a 
temperature of 50.degree. C. and a relative humidity of 80% for 2 hours, 
and then examined by X-ray diffractometry again. The peak due to silver 
bromide (2.theta.=31.0.degree.) or the peak due to silver iodide 
(2.theta.=23.7.degree.) should be substantially observed [the relative 
intensity of said peak is about 10 or more when the relative intensity of 
the peak due to silver behenate (2.theta.=12.1.degree.) is defined as 
100]. 
In the above test, the values of 2.theta. are those of diffraction peaks 
obtained by using CuK.sub..alpha. line. In the present invention, as the 
apparatus for X-ray diffractometry is used an apparatus of Rotor Unit type 
(RU-200 PL type) manufactured and sold by Rigaku Denki Kabushiki Kaisha, 
Japan. 
Specific examples of halogeno compounds capable of being used as the 
photoreactive halogeno oxidizing agent (e) include 
.alpha.,.alpha.,.alpha.',.alpha.'-tetrabromo-o-xylene, 
.alpha.,.alpha.,.alpha.',.alpha.'-tetrabromo-m-xylene, ethyl 
.alpha.,.alpha.,.alpha.-tribromoacetate, 
.alpha.,.alpha.,.alpha.-tribromoacetophenone, 
.alpha.,.alpha.,.alpha.-tribromo-p-bromotoluene, 
1,1,1-tribromo-2,2-diphenylethane, tetrabromomethane, 
meso-1,2,3,4-tetrabromobutane, 2,2,2-tribromoethanol, 
2,2,2-tribromoethylcyclohexyl carbamate, 2,2,2-tribromoethylphenyl 
carbamate, 2,2,2-tribromoethyl benzoate, 2,2,2-tribromoethyl 
ethylcarbamate, 2-methyl-1,1,1-tribromo-2-propanol, 
bis(2,2,2-tribromoethoxy) diphenylmethane, 2,2,2-tribromoethyl stearate, 
2,2,2-tribromoethyl-2-furoate, bis(2,2,2-tribromoethyl) succinate, 
2,2,2-tribromoethyl phenylsulfonate, 2,2,2-tribromoethoxytrimethyl-silane, 
2,2,2-tribromo-1-phenylethanol, 2,2,2-tribromoethyldiphenyl phosphate, 
1,2-diiodoethane and iodoform. They may be employed either alone or in 
combination. Of them, the bromo compounds are preferred since they give 
little coloring and improved stability to the resulting raw dry image 
forming material. Especially preferred are 
.alpha.,.alpha.,.alpha.',.alpha.'-tetrabromo-o-xylene, 
.alpha.,.alpha.,.alpha.',.alpha.'-tetrabromo-m-xylene, ethyl 
.alpha.,.alpha.,.alpha.-tribromoacetate, 
.alpha.,.alpha.,.alpha.-tribromo-p-bromotoluene, 
.alpha.,.alpha.,.alpha.-tribromoacetophenone, 
1,1,1-tribromo-2,2-diphenylethane, 2,2,2-tribromoethanol and 
meso-1,2,3,4-tetrabromobutane. Most preferred are 
.alpha.,.alpha.,.alpha.',.alpha.'-tetrabromo-o-xylene and 
.alpha.,.alpha.,.alpha.',.alpha.'-tetrabromo-m-xylene. The amount of the 
photoreactive halogeno oxidizing agent (e) is preferably 2.5 to 40 mole %, 
based on the silver salt of long chain fatty acid (a). 
As the binder (f) to be used in the dry image forming material of the 
present invention, there can be mentioned, for example, film-forming 
polymer materials such as, polyvinyl butyral, polymethyl methacrylate, 
cellulose acetate, polyvinyl acetate, cellulose acetate propionate, 
cellulose acetate butyrate, vinyl chloride-vinyl acetate copolymers, 
polyvinyl alcohol, polystyrene, polyvinyl formal and gelatin. Polyvinyl 
butyral is the most preferred binder. They may be used either alone or in 
combination. It is preferred that the binder be used in such an amount 
that the weight ratio of the binder to the long chain fatty acid silver 
salt (a) is in the range of from about 0.1 to about 10. 
The spectral sensitizing dye (g) to be used in the dry image forming 
material of the present invention is selected from those compounds each 
represented by one of the general formulae (I), (II), (III) and (IV) 
mentioned hereinbefore. The amount of the component (g) is preferably in 
the range of from 0.001 to 1 mole %, based on the component (a). 
Specific examples of the component (g) include the following compounds: 
##STR3## 
According to need, the post-activation type dry image forming material of 
the present invention may comprise in addition to the foregoing essential 
components a variety of additives such as a chemical sensitizer, a toner 
for a silver image and/or a development promotor. 
Among chemical sensitizers which improve the sensitivity of the dry image 
forming material of the present invention, those liable to spoil greatly 
the storage stability of the dry image forming material prior to the use 
thereof are not preferred. As chemical sensitizers which substantially 
improve the sensitivity of but not substantially spoil the storage 
stability of the dry image forming material of the present invention, 
there can be mentioned, for example, amide compounds as disclosed in 
Japanese Patent Application Laid-Open Specification No. 7914/1976, e.g. 
1-methyl-2-pyrrolidone; quinoline compounds as disclosed in Deutsche 
Offenlegungsschrift No. 2,845,187 and represented by the following general 
formula: 
##STR4## 
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 R.sub.5 and R.sub.6, each 
independently, is a hydrogen atom, an aryl group selected from phenyl and 
naphthyl groups unsubstituted or substituted with methyl, methoxy or 
halogen, a C.sub.1 -C.sub.10 straight or branched chain alkyl group, a 
C.sub.1 -C.sub.4 alkoxyl group, an aralkyl group selected from benzyl and 
phenethyl groups unsubstituted or substituted with methyl, methoxy or 
halogen, a hydroxyl group, a cyano group, a carboxyl group, a C.sub.2 
-C.sub.5 alkoxycarbonyl group, a nitro group, an amino group or a 
carbamoyl group, and D is a hydrogen atom, a hydroxyl group or an amino 
group; and 3-pyrazolin-5-one compounds as disclosed in Deutshe 
Offenlegungsschrift No. 2,934,751 and represented by the following 
formula: 
##STR5## 
wherein R.sub.7 is a hydrogen atom, a C.sub.1 -C.sub.5 straight or 
branched chain alkyl group, an unsubstituted or substituted phenyl group 
or an unsubstituted or substituted C.sub.3 -C.sub.8 cycloalkyl group, 
R.sub.8 is a C.sub.1 -C.sub.5 straight or branched chain alkyl group, an 
unsubstituted or substituted phenyl group or an unsubstituted or 
substituted C.sub.3 -C.sub.8 cycloalkyl group, and R.sub.9 and R.sub.10 
are the same or different and each represents a hydrogen atom, a C.sub.1 
-C.sub.5 straight or branched chain alkyl group, an unsubstituted or 
substituted phenyl group or an unsubstituted or substituted phenylalkyl 
group having a C.sub.1 -C.sub.5 straight or branched chain alkyl moiety. 
They may be used either alone or in combination preferably in an amount of 
5 to 50 mole %, based on the silver salt of long chain fatty acid (a). 
Specific examples of 3-pyrazolin-5-one compounds include 
2-phenyl-3-pyrazolin-5-one, 
1-(p-iodophenyl)-2,3-dimethyl-3-pyrazolin-5-one, 2,3,4-triphenyl- 
3-pyrazolin-5-one, 1-phenyl-2,3-dimethyl-3-pyrazolin-5-one, 
1,3-diethyl-2-phenyl-3-pyrazolin-5-one, 
2,3-dimethyl-1-ethyl-4-isopropyl-3-pyrazolin-5-one, 
2-o-tolyl-3-methyl-4-ethyl-3-pyrazolin-5-one, 
2-cyclohexyl-3-pyrazolin-5-one, 2-methyl-1,3-diphenyl-3-pyrazolin-5-one 
and 1-cyclohexyl-2,3-dimethyl-3-pyrazolin-5-one. The post-activation type 
dry image forming material of the present invention, even when containing 
a chemical sensitizer as mentioned above for improving the sensitivity, 
exerts the effects as intended in the present invention. 
As the toner for a silver image, there can be mentioned, for example, 
phthalazinone, zinc acetate, cadmium acetate, phthalimide and succinimide. 
They may be used either alone or in combination. The amount of the toner 
for a silver image is preferably in the range of from 1 to 100 mole %, 
based on the component (a). 
The preferred method of preparing the dry image forming material of this 
invention is described by way of example as follows. An silver salt of 
long chain fatty acid is dispersed in a binder-forming polymer solution by 
means of a ball mill, a homogenizer, a mixer, a sand mill or the like. To 
the resulting dispersion are added the other essential components and 
optionally various additives. The composition thus obtained is applied 
onto a support such as a plastic film, a glass plate, a paper or a metal 
plate, followed by drying, to prepare a dry image forming material. As the 
plastic film, there can be mentioned a polyethylene film, a cellulose 
acetate film, a polyethylene terephthalate film, a polyamide film, a 
polypropylene film and the like. The dry thickness of the coating as the 
image forming layer may be 1 to 100.mu., preferably 3 to 20.mu.. The 
essential components of the image forming material of the present 
invention may be applied either in one layer as described above, or in two 
or more separate but contiguous layers, for example, as will be described 
below. 
[1] A composition containing the components (a), (c), (d), (e) and (f) is 
applied onto a support, followed by drying, to form a first coating layer. 
Subsequently, a composition containing the components (b), (g) and (f) is 
applied onto the first coating layer and dried to form a second coating 
layer. 
[2] A composition containing the components (a), (c), (d), (e), (f) and (g) 
is applied onto a support, followed by drying, to form a first coating 
layer. Subsequently, a composition containing the components (b) and (f) 
is applied onto the first coating layer and dried to form a second coating 
layer. 
[3] A composition containing the components (a), (c), (d), (g) and (f) is 
applied onto a support, followed by drying, to form a first coating layer. 
Subsequently, a composition containing the components (b), (e) and (f) is 
applied onto the first coating layer and dried to form a second coating 
layer. 
For the purposes of the protection of the heat-activatable and 
heat-developable image forming layer and so on, a top coat may be 
provided. The material for the top coat may be chosen from among the 
binder materials as mentioned hereinbefore. Since the post-activation type 
dry image forming material of the present invention is non-photosensitive 
under normal lighting conditions, the preparation, application to a 
support and subsequent drying of a composition or compositions containing 
the essential components may be carried out even in a light room, but 
preferably at a temperature of 50.degree. C. or less. 
The sheet material so prepared does not lose an image-forming capacity even 
if stored under normal lighting conditions and it can be handled in a 
light room. When a given area of this sheet material is heated in the 
dark, this area is rendered photosensitive. This preliminary heating is 
preferably carried out at a temperature of about 90.degree. to about 
130.degree. C. As the heating temperature is elevated, the heating time 
may be proportionally shortened. When the area rendered photosensitive by 
heating is exposed imagewise to light and then heat-developed, a visible 
image is obtained. It is preferred that heat development be carried out at 
a temperature of about 90.degree. to about 150.degree. C. The heating time 
at the step of either preliminary heating or heat development may be 
controlled within the range of from about 1 to about 30 seconds. When the 
preliminary heating for rendering the material photosensitive and the heat 
development are conducted at the same temperature, the time for the heat 
development is generally equal to or longer than the time for the 
preliminary heating. In the image forming material of this invention, a 
visible image can be recorded selectively on a given area, and updated 
information may be additionally recorded on other area according to need. 
Furthermore, the image forming material of this invention can form thereon 
an image by photographing even a colored manuscript. 
The following Examples illustrate the present invention in more detail but 
should not be construed as limiting the scope of the invention. 
In the following Examples and Comparative Examples, the relative 
sensitivity and retention of sensitivity of dry image forming material are 
evaluated as follows. 
The sensitivity of dry image forming material is defined to be expressed by 
the reciprocal of amount of exposure light required for giving an optical 
density (O.D.) 0.6 higher than the minimum optical density (O.D. min) of 
dry image forming material. Relative sensitivity (R.S.) is given herein in 
terms of a proportion of the sensitivity of dry image forming material 
relative to the sensitivity of a given dry image forming material whose 
relative sensitivity is defined as 100. 
The retention of sensitivity is given herein in terms of a ratio of 
sensitivity of dry image forming material subjected to an accelerated 
deterioration test [using a fadeometer FX-1 (trade name of a product 
manufactured and sold by Suga Shikenki K. K., Japan) in Examples 1 to 18 
and 23 to 30 and Comparative Examples 1 to 22 and 29 to 30 or a Duplifiche 
Printer 261 (trade name of a microfiche duplicator manufactured and sold 
by Minesota Mining and Manufacturing Company, U.S.A.) in Examples 19 to 22 
and Comparative Examples 23 to 28] relative to sensitivity of the 
corresponding dry image forming material not subjected to the accelerated 
deterioration test. 
EXAMPLES 1 TO 3 AND COMATIVE EXAMPLES 1 TO 6 
To 20 g of a mixed solvent of toluene and methyl ethyl ketone (mixing 
weight ratio=1:2) was added 3 g of silver behenate, and the mixture was 
ball-milled for about 18 hours to obtain a homogeneous silver behenate 
suspension. 
To 1.5 g of the silver behenate suspension were added ingredients [I] as 
shown below to form a silver behenate emulsion. The silver behenate 
emulsion was uniformly applied onto a 100 .mu.-thick polyethylene 
terephthalate film at an orifice of 100.mu., and air-dried at room 
temperature (about 20.degree. C.) to form a first coating layer. The 
amount of silver behenate contained in the first coating layer was about 4 
g/m.sup.2 of the layer. About 2 g of a reducing agent-containing 
composition composed of ingredients [II] as shown below was uniformly 
applied as a second coating layer onto the first coating layer at an 
orifice of 75.mu., and air-dried at room temperature (20.degree. C.) to 
obtain a dry image forming material having a total coating layer thickness 
of about 12.mu.. 
______________________________________ 
Ingredients [I] 
______________________________________ 
15 Weight % solution of polyvinyl 
1.3 g 
butyral in methyl ethyl ketone 
Solution of 100 mg of mercuric 
0.5 cc 
iodide in 9 cc of acetone 
Bis-p-methoxyphenyltellurium diiodide 
28 mg 
Bis-p-methoxyphenyltellurium dibromide 
14 mg 
meso-1,2,3,4-Tetrabromobutane 
25 mg 
Quinoline 30 mg 
Solution of 10 mg of dye compound as 
0.1 cc 
indicated in Table 1 in 10 cc of methanol 
Cellulose acetate 6.3 g 
2,6-Methylenebis(2-hydroxy-3-tert- 
3.2 g 
butyl-5-methylphenyl)-4-methylphenol 
Acetone 83.0 g 
Phthalazinone 1.2 g 
______________________________________ 
A piece of the dry image forming material was preliminarily heated on a hot 
plate maintained at about 100.degree. C. for 3 seconds in a dark room. 
Then, the material was exposed for 1 second through a 21-step steptablet 
(manufactured and sold by Eastman Kodak Co., Ltd., U.S.A.) to light 
emitted from a tungsten lamp having a color temperature of 3,200.degree. 
K. and filtered through a yellow color filter Y-50 (trade name of a color 
filter manufactured and sold by Tokyo Shibaura Electric Company Ltd., 
Japan). The exposed material was then heated on a hot plate maintained at 
about 120.degree. C. for 5 seconds in the dark room to effect heat 
development. 
Another piece of the dry image forming material was subjected to an 
accelerated deterioration test which was carried out under a light of 
200,000 luxes for one hour by means of the fadeometer FX-1. The 
deteriorated material was subjected to image formation which was carried 
out in the same manner as described above. 
The optical densities of the imaged materials respectively derived from the 
materials before and after subjected to the accelerated deterioration test 
were measured. The results evaluated in the terms of relative sensitivity, 
fogging and retention of sensitivity are shown in Table 1, in which (1), 
(4) and (11) indicates the aforementioned spectral sensitizing dye 
compounds listed under such numbers (such indications used hereinafter 
have the same meanings), and in which the standard material with a 
relative sensitivity of 100 is of Example 1. 
TABLE 1 
______________________________________ 
Before 
Accelerated 
After 
Deterioration 
Accelerated 
Rela- Fog- Deterioration 
Dye tive ging Retention 
Com- Sensi- (O.D. of Sensi- 
Fogging 
Run No. pound tivity min) tivity (O.D. min) 
______________________________________ 
Example 1 
(1) 100 0.09 0.71 0.11 
Example 2 
(4) 402 0.09 0.60 0.12 
Example 3 
(11) 253 0.09 0.51 0.12 
Comparative 
Example 1 
none 0 0.08 0 0.10 
Comparative 
Example 2 
(a) 11 1.02 0 0.10 
Comparative 
Example 3 
(b) 5 0.60 0 0.10 
Comparative 
Example 4 
(c) 12 1.2 0 0.10 
Comparative 
Example 5 
(d) 12 1.0 0 0.10 
Comparative 
Example 6 
(e) 5 0.20 0 0.10 
______________________________________ 
The comparative dye compounds (a) to (e) used in Comparative Examples 2 to 
6, respectively, are mentioned below. 
##STR6## 
(mentioned in Japanese Patent Application Laid-Open Specification No. 
137321/1977) 
##STR7## 
(mentioned in Japanese Patent Application Laid-Open Specification No. 
17719/1974) 
##STR8## 
(mentioned in Japanese Patent Publication No. 41967/1978) 
(d) 
3-Allyl-5-[3-ethyl-(2-naphthoxazolidine)-ethylidene]-1-phenyl-2-thiohydant 
oin (mentioned in Japanese Patent Application Laid-Open Specification No. 
51626/1973) 
##STR9## 
As is apparent from the results shown in Table 1, spectral sensitizing dye 
compounds (1), (4) and (11) used in the dry image forming materials of the 
present invention are by far superior in spectral sensitization, 
suppression of fogging in image forming materials before storage and 
retention of sensitivity of raw dry image forming material during storage 
thereof to the merocyanine, styryl and xanthene dyes, which, in addition 
to poor sensitization, develop a large fogging tendency in dry image 
forming materials at the steps of preliminary heating and heat development 
and do not contribute at all to promotion of retention of sensitivity of 
raw dry image forming materials during storage thereof. 
EXAMPLES 4 TO 7 AND COMATIVE EXAMPLES 7 TO 12 
To 1.5 g of a silver behenate suspension as prepared in the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 were added ingredients 
[III] as shown below to form a silver behenate emulsion. The silver 
behenate emulsion was applied onto a 100 .mu.-thick polyethylene 
terephthalate film and air-dried in the same manner as in Examples 1 to 3 
and Comparative Examples 1 to 6 to form a first coating layer. About 2 g 
of a reducing agent-containing composition composed of ingredients [IV] as 
shown below was uniformly applied as a second coating layer and air-dried 
in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 6 
to obtain a dry image forming material. 
______________________________________ 
Ingredients [III] 
15 Weight % solution of polyvinyl 
1.3 g 
butyral in methyl ethyl ketone 
Solution of 100 mg of mercuric 
0.5 cc 
iodide in 9 cc of acetone 
2,2,2-Tribromoethanol 45 mg 
N-Iodosuccinimide 6.3 mg 
Cobalt dibromide 3 mg 
1-Phenyl-2,3-dimethyl-3-pyrazolin- 
20 mg 
5-one 
Solution of 10 mg of dye compound as 
0.2 cc 
indicated in Table 2 in 10 cc of methanol 
Ingredients [IV] 
Cellulose acetate 6.3 g 
2,4,4-Trimethylpentylbis(2-hydroxy- 
2.8 g 
3,5-dimethylphenyl)methane 
Phthalazinone 1.2 g 
Acetone 83.0 g 
______________________________________ 
The relative sensitivity, fogging and retention of sensitivity of the dry 
image forming material were examined in the same manner as in Examples 1 
to 3 and Comparative Examples 1 to 6, and were found to be as shown in 
Table 2, in which the standard material with a relative sensitivity of 100 
is of Example 4. 
TABLE 2 
______________________________________ 
Before 
Accelerated 
After 
Deterioration 
Accelerated 
Rela- Fog- Deterioration 
Dye tive ging Retention 
Com- Sensi- (O.D. of Sensi- 
Fogging 
Run No. pound tivity min) tivity (O.D. min) 
______________________________________ 
Example 4 
(2) 100 0.09 0.69 0.11 
Example 5 
(5) 102 0.09 0.71 0.11 
Example 6 
(7) 205 0.09 0.95 0.11 
Comparative 
Example 7 
none 0 0.08 -- 0.10 
Comparative 
Example 8 
(f) 0 1.02 -- 0.30 
Comparative 
Example 9 
(g) 31 0.62 -- 0.31 
Comparative 
Example 10 
(h) 40 0.40 0.10 0.25 
Comparative 
Example 11 
(i) 52 0.31 0.21 0.20 
Comparative 
Example 12 
(j) 0 0.31 -- 0.31 
______________________________________ 
The comparative dye compounds (f) to (j) used in Comparative Examples 8 to 
12, respectively, are mentioned below. 
##STR10## 
As is apparent from the results shown in Table 2, the disulfopropyl type 
spectral sensitizing dye compounds (2), (5) and (7) used in the dry image 
forming materials of the present invention are by far superior in spectral 
sensitization, suppression of fogging at the steps of preliminary heating 
and heat development of materials before storage, retention of sensitivity 
of raw materials, and suppression of fogging in materials after storage to 
the monosulfopropyl type, non-sulfoalkyl type, disulfoethyl type, 
di-3-sulfobutyl type and dicarboxypropyl type dyes. 
EXAMPLES 8 TO 12 AND COMATIVE EXAMPLES 13 TO 17 
A dry image forming material was prepared in substantially the same manner 
as in Examples 4 to 7 and Comparative Examples 7 to 12 except that a dye 
compound as indicated in Table 3 was used instead of that in ingredients 
[III]. 
The relative sensitivity, fogging and retention of sensitivity of the dry 
image forming material were examined in substantially the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 except that the light 
exposure was carried out for 8 seconds by using a light with a wavelength 
of 480 nm emitted from a monochrometer, and were found to be as shown in 
Table 3, in which the standard material with a relative sensitivity of 100 
is of Example 8. 
TABLE 3 
______________________________________ 
Before 
Accelerated 
After 
Deterioration 
Accelerated 
Rela- Fog- Deterioration 
Dye tive ging Retention 
Com- Sensi- (O.D. of Sensi- 
Fogging 
Run No. pound tivity min) tivity (O.D. min) 
______________________________________ 
Example 8 
(15) 100 0.09 0.60 0.10 
Example 9 
(17) 152 0.09 0.95 0.10 
Example 10 
(18) 123 0.09 0.61 0.21 
Example 11 
(19) 151 0.09 0.52 0.10 
Example 12 
(20) 173 0.09 0.51 0.10 
Comparative 
Example 13 
none 0 0.09 -- 0.10 
Comparative 
Example 14 
(k) 0 1.10 -- 0.31 
Comparative 
Example 15 
(l) 0 1.00 -- 0.30 
Comparative 
Example 16 
(m) 0 0.09 -- 0.10 
Comparative 
Example 17 
(n) 12 0.09 0.10 0.12 
______________________________________ 
The comparative dye compounds (k) to (n) used in Comparative Examples 14 to 
17, respectively, are mentioned below. 
##STR11## 
As is apparent from the results shown in Table 3, the disulfopropyl type 
spectral sensitizing dye compounds (15), (17), (18), (19) and (20) used in 
the dry image forming materials of the present invention are by far 
superior in spectral sensitization, suppression of fogging at the steps of 
preliminary heating and heat development of materials before storage, 
retention of sensitivity of raw materials and suppression of fogging in 
materials after storage to the non-sulfoalkyl type dyes, and superior in 
spectral sensitization and retention of sensitivity of raw dry image 
forming materials during storage thereof to even the disulfopropyl type 
dyes of the formulae similar to but different from the formula (III). The 
dye compound (m) has oxygen atoms at the positions corresponding to the Z 
position in the formula (III). The dye compound (n) has a methoxy group at 
one of the positions corresponding to the R positions in the formula 
(III). 
EXAMPLES 13 TO 18 AND COMATIVE EXAMPLES 18 TO 22 
To 20 g of a mixed solvent of toluene and methyl ethyl ketone (mixing 
weight ratio=1:2) was added 3.5 g of silver stearate, and the mixture was 
ball-milled for about 18 hours to obtain a homogeneous silver stearate 
suspension. 
To 1.5 g of the silver stearate suspension were added ingredients [V] as 
shown below to form a silver stearate emulsion. The silver stearate 
emulsion was applied onto a 100.mu.-thick polyethyrene terephthalate film 
and air-dried in the same manner as in Examples 1 to 3 and Comparative 
Examples 1 to 6 to form a first coating layer. About 2 g of a reducing 
agent-containing composition composed of ingredients [VI] as shown below 
was applied as a second coating layer and air-dried in the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 to obtain a dry image 
forming material. 
______________________________________ 
Ingredients [V] 
15 Weight % solution of polyvinyl 
butyral methyl ethyl ketone 
1.3 g 
N-Iodosuccinimide 6.3 mg 
Diphenylbromomethane 4.0 mg 
Solution of 10 mg of mercuric 
acetate in 3 cc of methanol 
0.15 cc 
.alpha.,.alpha.,.alpha.',.alpha.'-Tetrabromo-m-xylene 
30 mg 
Solution of 1 mg of dye compound as 
indicated in Table 4 in 1 cc of methanol 
0.1 cc 
Ingredients [VI] 
Polymethyl methacrylate 6.3 g 
2,2'-Methylenebis(4-ethyl- 
6-tert-butylphenol) 3.5 g 
Phthalazinone 1.2 g 
Methyl ethyl ketone 83.0 g 
______________________________________ 
The relative sensitivity, fogging and retention of sensitivity of the dry 
image forming material were examined in the same manner as in Examples 1 
to 3 and Comparative Examples 1 to 6, and were found to be as shown in 
Table 4, in which the standard material with a relative sensitivity of 100 
is of Example 13. 
TABLE 4 
__________________________________________________________________________ 
Before Accelerated 
After Accelerated 
Deterioration 
Deterioration 
Dye Relative 
Fogging 
Retention of 
Fogging 
Run No. 
Compound 
Sensitivity 
(O.D. min) 
Sensitivity 
(O.D. min) 
__________________________________________________________________________ 
Example 13 
(1) 100 0.11 0.61 0.20 
Example 14 
(4) 400 0.11 0.72 0.12 
Example 15 
(3) 200 0.11 0.90 0.12 
Example 16 
(7) 200 0.11 0.96 0.12 
Example 17 
(11) 250 0.11 0.53 0.12 
Example 18 
(22) 150 0.11 0.60 0.12 
Comparative 
Example 18 
none 0 0.08 -- 0.11 
Comparative 
Example 19 
(o) 100 0.11 0.18 0.28 
Comparative 
Example 20 
(p) 70 0.11 0.11 0.50 
Comparative 
Example 21 
(q) 50 0.11 0.10 0.31 
Comparative 
Example 22 
(r) 100 0.11 0 0.15 
__________________________________________________________________________ 
The comparative dye compounds (o) to (r) used in Comparative Examples 19 to 
22, respectively, are mentioned below. 
##STR12## 
As is apparent from the results shown in Table 4, the spectral sensitizing 
dye compounds (1), (4), (3), (7), (11) and (22) respectively employed in 
the dry image forming materials of the present invention are superior in 
spectral sensitization, retension of spectral sensitivity of raw materials 
during storage thereof, and suppression of fogging in materials stored 
under lighting conditions to those comparative dye compounds employed in 
Comparative Examples 19 to 22, which have a benzoxazole skeletal 
structure. 
EXAMPLES 19 TO 22 AND COMATIVE EXAMPLES 23 TO 28 
To 1.5 g of a silver behenate suspension as prepared in the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 were added ingredients 
[VII] as shown below to form a silver behenate emulsion. The silver 
behenate emulsion was applied onto a 100.mu.-thick polyethylene 
terephthalate film and air-dried in the same manner as in Examples 1 to 3 
and Comparative Examples 1 to 6 to form a first coating layer. About 2 g 
of a reducing agent-containing composition composed of ingredients [VI] as 
used in Examples 13 to 18 and Comparative Examples 18 to 22 was applied as 
a second coating layer and air-dried in the same manner as in Examples 1 
to 3 and Comparative Examples 1 to 6 to obtain a dry image forming 
material. 
______________________________________ 
Ingredients [VII] 
______________________________________ 
15 Weight % solution of polyvinyl 
butyral in methyl ethyl ketone 
1.3 g 
Solution of 100 mg of mercuric 
acetate in 3 cc of methanol 
0.15 cc 
Iodine 8 mg 
Triphenyl phosphite 4 mg 
Diphenylbromomethane 4 mg 
1-Phenyl-2,3-dimethyl-3- 
pyrazolin-5-one 30 mg 
.alpha.,.alpha.,.alpha.', .alpha.'-Tetrabromo- 
35 mg 
o-xylene 
Solution of 10 mg of dye compound as 
indicated in Table 5 in 10 cc methanol 
0.15 cc 
______________________________________ 
The relative sensitivity, fogging and retention of sensitivity of the dry 
image forming material were examined in substantially the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 except that the 
accelerated deterioration test was carried out by passing the raw material 
50 times through the microfiche duplicator, and were found to be as shown 
in Table 5, in which the standard material with a relative sensitivity of 
100 is of Example 19. 
TABLE 5 
______________________________________ 
Before 
Accelerated 
After 
Deterioration 
Accelerated 
Rela- Fog- Deterioration 
Dye tive ging Retention 
Com- Sensi- (O.D. of Sensi- 
Fogging 
Run No. pound tivity min) tivity (O.D. min) 
______________________________________ 
Example 19 
(5) 100 0.09 0.85 0.10 
Example 20 
(3) 200 0.09 1.0 0.10 
Example 21 
(11) 250 0.09 0.80 0.10 
Example 22 
(23) 80 0.09 0.57 0.10 
Comparative 
Example 23 
(s) 40 0.09 0.30 0.20 
Comparative 
Example 24 
(t) 60 0.09 0.20 0.21 
Comparative 
Example 25 
(u) 20 0.09 0.1 0.20 
Comparative 
Example 26 
(v) 5 0.09 0.1 0.25 
Comparative 
Example 27 
(w) 10 0.09 0.1 0.18 
Comparative 
Example 28 
(x) 30 0.17 0.1 0.17 
______________________________________ 
The comparative dye compounds (s) to (x) used in Comparative Examples 23 to 
28, respectively, are mentioned below. 
##STR13## 
As is apparent from the results shown in Table 5, the spectral sensitizing 
dye compounds (5), (3), (11) and (23) used in the dry image forming 
materials of the present invention are superior in retension of spectral 
sensitivity of raw materials and suppression of fogging in materials after 
storage as well as spectral sensitization to the comparative dye compounds 
similar to but different from those specified in the present invention. 
The dye compounds (s) to (v) have an ethyl group at the meso-position 
corresponding to the Y position in the formula (I) or (II). The dye 
compounds (v) to (x) has, as the substituent(s) of the benzthiazole ring 
or benzselenazole ring, one or two methyl groups at one or both of the 
positions corresponding to the R positions in the formula (I). 
EXAMPLES 23 TO 27 AND COMATIVE EXAMPLE 29 
To 1.5 g of a silver behenate suspension as prepared in the same manner as 
in Example 1 were added ingredients [VIII] as shown below to form a silver 
behenate emulsion. The silver behenate emulsion was applied onto a 
100.mu.-thick polyethylene terephthalate film and air-dried in the same 
manner as in Examples 1 to 3 and Comparative Examples 1 to 6 to form a 
first coating layer. About 2 g of a reducing agent-containing composition 
composed of ingredients [IX] as shown below was applied as a second 
coating layer and air-dried in the same manner as in Examples 1 to 3 and 
Comparative Examples 1 to 6 to obtain a dry image forming material. 
______________________________________ 
Ingredients [VIII] 
15 Weight % solution of polyvinyl butyral 
in methyl ethyl ketone 1.3 g 
Solution of 100 mg of mercuric acetate 
in 3 cc of methanol 0.15 cc 
.alpha.,.alpha.,.alpha.',.alpha.'-Tetrabromo-o-xylene 
25 mg 
Triphenyl phosphite 3 mg 
The amount is 
Iodine indicated in Table 6. 
The amount is 
Diphenylbromomethane indicated in Table 6. 
1-Phenyl-2-methyl-3-phenyl-3- 
pyrazolin-5-one 35 mg 
Solution of 1 mg of dye compound (7) 
in 1 cc methanol 0.1 cc 
Ingredients [IX] 
Cellulose acetate 6.3 mg 
2,2'-methylenebis(4-ethyl-6-tert- 
buthylphenol) 3.5 g 
Phthalazinone 1.2 g 
Acetone 83.0 g 
______________________________________ 
The relative sensitivity, fogging and retention of sensitivity of the dry 
image forming material were examined in the same manner as in Examples 1 
to 3 and Comparative Examples 1 to 6, and were found to be as shown in 
Table 6, in which the standard material with a relative sensitivity of 100 
is of Example 23. 
TABLE 6 
__________________________________________________________________________ 
Halogenating Agent Molar 
Before Accelerated 
After Accelerated 
Diphenyl- 
Ratio 
Deterioration 
Deterioration 
Iodine 
bromomethane 
of Relative 
Fogging 
Retention of 
Fogging 
Run No. 
(mg) (mg) I/Br 
Sensitivity 
(O.D. min) 
Sensitivity 
(O.D. min) 
__________________________________________________________________________ 
Example 23 
8 4 79/21 
100 0.09 0.93 0.11 
Example 24 
9.4 1 95/5 
50 0.09 0.90 0.11 
Example 25 
4.9 9.3 51/49 
130 0.09 0.87 0.11 
Example 26 
12 0 100/0 
10 0.15 0.40 0.11 
Example 27 
3.1 13.5 31/69 
120 0.09 0.90 0.18 
Comparative 
Example 29 
0 24 0/100 
10 0.09 0 1.8 
__________________________________________________________________________ 
As is apparent from the results shown in Table 6, it is necessary from the 
viewpoint of raw materials that the silver halide-forming component 
include silver iodide-forming compound so that the silver halide component 
formed therefrom includes silver iodide. 
EXAMPLES 28 AND 29 AND COMATIVE EXAMPLE 30 
To 1.5 g of a silver behenate suspension as prepared in the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 were added ingredients 
[X] as shown below to form a silver behenate emulsion. The silver behenate 
emulsion was applied onto a 100.mu.-thick polyethylene terephthalate film 
and air-dried in substantially the same manner as in Examples 1 to 3 and 
Comparative Examples 1 to 6 to form a first coating layer. A composition 
composed of ingredients [VI] as used in Examples 13 to 18 and Comparative 
Examples 18 to 22 was applied as a second coating layer and air-dried in 
substantially the same manner as in Examples 1 to 3 and Comparative 
Examples 1 to 6 to obtain a dry image forming material. 
______________________________________ 
Ingredients [X] 
______________________________________ 
15 Weight % solution of polyvinyl butyral 
in methyl ethyl ketone 1.3 g 
Iodine 15 mg 
Triphenyl phosphite 4 mg 
Nickel dibromide 5 mg 
Solution of 1 mg of dye compound (3) 
in 1 cc of methanol 0.1 cc 
Compound(s) indicated as the 
The amount(s) is(are) 
component (d) and/or (e) in Table 7 
indicated in Table 7. 
______________________________________ 
The relative sensitivity, fogging and retention of sensitivity of the dry 
image forming material were examined in the same manner as in Examples 1 
to 3 and Comparative Examples 1 to 6, and were found to be as shown in 
Table 7, in which the standard material with a relative sensitivity of 100 
is of Comparative Example 30. 
TABLE 7 
__________________________________________________________________________ 
Before Accelerated 
After Accelerated 
Deterioration 
Deterioration 
Relative 
Fogging 
Retention of 
Fogging 
Run No. 
Component (d) 
Component (e) 
Sensitivity 
(O.D. min) 
Sensitivity 
(O.D. min) 
__________________________________________________________________________ 
Example 28 
Co(III) .alpha.,.alpha.,.alpha.',.alpha.'- 
90 0.15 0.80 0.18 
acetylacetonate 
tetrabromo-o- 
5 mg xylene 
25 mg 
Example 29 
Pd(II) .alpha.,.alpha.,.alpha.',.alpha.'- 
80 0.13 0.76 0.23 
acetylacetonate 
tetrabromo-o- 
5 mg xylene 
25 mg 
Comparative 
Mercuric 
none 100 0.09 0 1.8 
Example 30 
acetate 
5 mg 
__________________________________________________________________________ 
EXAMPLE 30 
To 1.5 g of a silver behenate suspension as prepared in the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 were added ingredients 
[XI] as shown below to form a silver behenate emulsion. The silver 
behenate emulsion was applied onto a 100.mu.-thick polyethylene 
terephthalate film and air-dried in substantially the same manner as in 
Examples 1 to 3 and Comparative Examples 1 to 6 to form a first coating 
layer. A composition composed of ingredients [IX] as used in Examples 23 
to 27 and Comparative Example 29 was applied as a second coating layer and 
air-dried in the same manner as in Examples 1 to 3 and Comparative 
Examples 1 to 6 to obtain a dry image forming material. 
______________________________________ 
Ingredients [XI] 
______________________________________ 
15 Weight % solution of polyvinyl butyral 
in methyl ethyl ketone 1.3 g 
Solution of 100 mg of mercuric acetate 
in 3 cc of methanol 0.15 cc 
Silver Iodide 8.2 mg 
Silver bromide 1.2 mg 
.alpha.,.alpha.,.alpha.',.alpha.'-Tetrabromobutane 
30 mg 
1-Phenyl-2-methyl-3-phenyl-3-pyrazolin- 
5-one 35 mg 
Solution of 1 mg of dye compound (7) 
in 1 cc of methanol 0.1 cc 
______________________________________ 
The sensitivity, fogging and retention of sensitivity of the dry image 
forming material were examined in the same manner as in Examples 1 to 3 
and Comparative Examples 1 to 6. The sensitivity of the material was a 
tenth that of the material of Example 23. However, the fogging and 
stability of the raw material were substantially the same as those of the 
material of Example 23. 
EXAMPLE 31 AND COMATIVE EXAMPLE 31 
To 1.5 g of a silver behenate suspension as prepared in the same manner as 
in Examples 1 to 3 and Comparative Examples 1 to 6 were added ingredients 
[XII] as shown below to form a silver behenate emulsion. The silver 
behenate emulsion was applied onto a 100.mu.-thick polyethylene 
terephthalate film and air-dried in substantially the same manner as in 
Examples 1 to 3 and Comparative Examples 1 to 6 to form a first coating 
layer. A composition composed of ingredients [VI] as used in Examples 13 
to 18 and Comparative Examples 18 to 22 was applied as a second coating 
layer and air-dried in the same manner as in Examples 1 to 3 and 
Comparative Examples 1 to 6 to obtain a dry image forming material. 
______________________________________ 
Ingredients [XII] 
______________________________________ 
15 Weight % solution of polyvinyl butyral 
in methyl ethyl ketone 1.3 g 
Solution of 100 mg of mercuric acetate 
in 3 cc of methanol 0.15 cc 
Triphenyl phosphite 4 mg 
Iodine 8 mg 
Cobalt dibromide 5 mg 
1-Phenyl-2,3-dimethyl-3-pyrazolin- 
5-one 20 mg 
2,2,2-Tribromoethanol 30 mg 
Solutions of 10 mg each of dye 
The amounts are 
compounds as indicated in Table 8 
indicated in 
in 10 cc of methanol Table 8. 
______________________________________ 
A piece of dry image forming material was subjected to spectrographic 
analysis by means of a spectrograph (manufactured by Narumi Shokai, Japan) 
to obtain a spectral sensitivity curve. 
TABLE 8 
______________________________________ 
Spectral Sensitivity 
Run No. Dye Compound Curve 
______________________________________ 
Example 31 (3) + (17) FIG. 1 
0.1 cc 0.2 cc 
Comparative 
none FIG. 2 
Example 31 
______________________________________ 
As is apparent from the spectral sensitivity curves shown in FIG. 1 and 
FIG. 2, the combined use of the dye compounds (3) and (17) is effective 
for achieving, in the dry image forming material, well balanced spectral 
sensitization over the wide range of wavelengths of light. 
Another piece of the dry image forming material of Example 31 was 
heat-activated at 100.degree. C. for 3 seconds. Under the light of a 
fluorescent lamp, three manuscripts having a black image on each of a 
light-green, a light-yellow and a pink backgrounds were photographed on 
the activated material. The resulting material was heat-developed at 
125.degree. C. for 3 seconds. The images obtained were all very clear.