Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-10-16
2003-05-06
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S264000, C430S350000, C430S598000, C430S600000, C430S607000
Reexamination Certificate
active
06558896
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to thermally developable photographic light sensitive materials (silver salt photothermographic materials) and in particular to silver salt photothermographic materials used in the field of lithographic printing plates or medical treatment.
BACKGROUND OF THE INVENTION
In the field of graphic arts and medical treatment, there have been concerns in processing of photographic film with respect to effluent produced from wet-processing of image forming materials, and recently, reduction of the processing effluent is strongly demanded in terms of environmental protection and space saving. There has been desired a photothermographic dry imaging material for photographic use, capable of forming distinct black images exhibiting high sharpness, enabling efficient exposure by means of a laser imager or a laser image setter. Known as such a technique are silver salt photothermographic dry imaging materials forming photographic images through thermal processing, as described in U.S. Pat. Nos. 3,152,904 and 3,487,075, and D. H. Klosterboer, “Thermally Processed Silver Systems” in IMAGING PROCESSES and MATERIALS, Neblette's Eighth Edition, edited by J. M. Sturge, V. Walworth, and A. Shepp (1969) page 279.
Such a silver salt photothermographic material comprises a reducible silver source (such as light-insensitive organic silver salts), a catalytic active-amount of a photocatalyst (such as silver halide) and a reducing agent, which are dispersed in an organic binder matrix. The silver salt photothermographic material is stable at ordinary temperature but, when heated at a relative high temperature after exposure, forms metallic silver upon oxidation reduction reaction between the reducible silver source (which acts as an oxidant) and the reducing agent. Recently, studies of silver salt photothermographic materials have proceeded rapidly and photothermographic material satisfying basic performance are commercially available. However, there have arisen new problems, specifically those which concern systems including exposure and processing. Unevenness in density caused in development produces many problems. In the case of use for medical treatment, for example, when diagnosis is made employing a slight density difference, such problems can become quite critical. With regard to a technique for improving unevenness in developed density, a few techniques employing instruments have been reported but an improvements are still desired. Further, in silver salt photothermographic material is pointed out deteriorated image tone due to its development mechanism. Active studies have been made with respect to such problems and many techniques have been reported. However, an acceptable level has not been reached as yet and there is desired a technique for improving unevenness in development.
SUMMARY OF THE INVENTION
Accordingly, new problems have arisen with a system including exposure and development. In addition to the unevenness in density caused during development, unevenness in density caused by density variation after development is also a major problem. Specifically in medical use, when diagnosis is made employing a slight difference in density, the foregoing problems often lead to serious results. With regard to a technique for improving such density unevenness in development, a few techniques employing instruments have been reported but sufficient improvement has not yet been achieved, and prompt improvement is desired.
Deteriorated image tone which is contemplated to be due to the development mechanism is also pointed out.
Accordingly, it is an object of the present invention to provide a silver salt photothermographic material overcoming the foregoing problems.
The foregoing problems can be solved by the following constitution:
A silver salt photothermographic material comprising on a support (a) a light-insensitive organic silver salt, (b) silver halide and (c) a reducing agent capable of reducing a silver ion of the organic silver salt to silver upon heating, wherein when the photothermographic material having been exposed and thermally processed and having a density of 3.0 is kept at 50° C. and 50% RH for 120 hr., the photothermographic material exhibits a variation of density from 3.0 being within the range of ±0.2.
Furthermore, preferred effects can be achieved by the following embodiments.
(a) The photothermographic material described above, wherein the photothermographic material further comprises a compound represented by formula (1) and the reducing agent capable of reducing a silver ion of the organic silver salt is represented by formula (2) and contained in an amount of 35 to 100 mol %, based on the total organic silver salt, and a molar ratio of the compound represented by formula (2) to the compound represented by formula (1) being 10 to 50:
X═C═N—L—(N═C═X)
v
formula (1)
wherein v is 1 or 2; L is a bivalent linkage group having an alkylene group, an alkenylene group, arylene group or an alkylarylenes group; and X is an oxygen atom or a sulfur atom;
wherein R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (such as butyl or 2,4,4-trimethylpentyl); R′ and R″ are each an alkyl group having 1 to 5 carbon atoms (such as methyl, ethyl or t-butyl).
(b) The photothermographic material described above, wherein the photothermographic material further comprises a compound represented by formula (3) and a compound represented by formula (4):
Q-(Y)
n
—C(X1)(X2)(X3) formula (3)
wherein Q is an aryl group or a heterocyclic group; Y is a bivalent linkage group including SO, SO
2
or CO; n is 0 or 1; X1, X2 and X3 are each a halogen atom;
Q′-(Y′)
n
—C(X′1)(X′2)(X′3) formula (4)
wherein Q′ is an aryl group or a heterocyclic group; Y′ is a bivalent linkage group including SO, SO
2
or CO; n is 0 or 1; X′1, X′2 and X′3 are each a hydrogen atom, a halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, or a heterocyclic group, provided that at least one of X′1, X′2 and X′3 is a halogen atom but all of them are not halogen atoms;
(c) The photothermographic material described above, wherein the photothermographic material further comprises a compound represented by formula (5) and a compound represented by formula (6):
Q″-(Y″)
n
—C(X″1)(X″2)(X″3) formula (5)
wherein Q″ is an aryl group or a heterocyclic group; Y″ is a bivalent linkage group including SO, SO
2
or CO; n is 0 or 1; X″1, X″2 and X″3 are each a hydrogen atom, a bromine atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, or a heterocyclic group, provided that at least one of X″1, X″2 and X″3 is a bromine atom;
Q″′-(Y″′)
n
—C(X″′1)(X″′2)(X″′3) formula (6)
wherein Q″′ is an aryl group or a heterocyclic group; Y″′ is a bivalent linkage group including SO, SO
2
or CO; n is 0 or 1; X″′1, X″′2 and X″′3 are each a chlorine atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, or a heterocyclic group, provided that at least one of X″′1, X″′2 and X″′3 is a chlorine atom.
(d) The photothermographic material described above, wherein the photothermographic material further comprises a silver-saving agent.
(e) The photothermographic material described above, wherein the photothermographic material comprises on the support at least two light-sensitive layers.
(f) An image recording method, wherein when recording an image on the photothermographic material described above, exposure is conducted u
Chea Thorl
Konica Corporation
Muserlian Lucas and Mercanti
LandOfFree
Silver salt photothermographic material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver salt photothermographic material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver salt photothermographic material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3028257