Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-11-15
2003-11-18
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S572000, C430S578000, C430S579000, C430S583000, C430S584000, C430S585000, C430S586000, C430S587000, C430S588000, C430S591000, C430S592000, C430S593000, C430S594000
Reexamination Certificate
active
06649337
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a heat-developable photosensitive material. More specifically, the present invention relates to a heat-developable photosensitive material that is excellent in sensitivity and storage stability.
BACKGROUND OF THE INVENTION
Reduction of waste solutions has been strongly desired in recent years in the field of films for medical diagnosis and photomechanical process from the viewpoint of environmental protection and space saving. Accordingly, techniques concerning heat-developable recording materials as the films for medical diagnosis and photomechanical process capable of performing exposure efficiently with a laser/image setter or a laser/imager and forming a clear black image exhibiting high resolution and sharpness have been required. Such a heat-developable recording material can offer to customers a simpler and environmentally benign heat development processing system in which chemicals in solution system is not necessary for processing.
There also arises the same requirement in the field of general image-forming materials, but particularly image for the medical diagnosis have characteristics in that a cold tone image is preferable because high image quality excellent in sharpness and graininess is necessary as precise imaging is required and, in addition, from the viewpoint of easiness of diagnosis. At present, various hard copy systems utilizing pigments and dyes such as ink jet printers and electrophotography prevail as general image-forming systems, but none of these systems are satisfactory as a medical image output system.
On the other hand, thermal image-forming systems making use of organic silver salts are described, e.g., in U.S. Pat. Nos. 3, 152,904 and 3,457,075, and D. Klosterboer,
Thermally Processed Silver Systems
, “Imaging Processes and Materials”, compiled by Sturge, V. Walworth, A. Shepp, 8th Ed., Chap. 9, p. 279, Neblette (1989).
A heat-developable photosensitive material generally has a photosensitive layer comprising a catalytically active amount of photocatalyst (e.g., a silver halide), a reducing agent, a reducible silver salt (e.g., an organic silver salt) and, if necessary, a toner which controls the tone of silver, which have been dispersed in a binder matrix. A heat-developable photosensitive material forms a black silver image by heating at high temperature (e.g., 80° C. or more) after image exposure to cause an oxidation reduction reaction between a reducible silver salt (which functions as an oxidizing agent) and a reducing agent. The oxidation reduction reaction is accelerated by the catalytic action of the latent image of the silver halide generated by exposure. Therefore, the black silver image is formed in the exposed area.
These heat-developable image-recording materials are described in various literature including U.S. Pat. No. 2,910,377 and JP-B-43-4924 (the term “JP-B” as used herein means an “examined Japanese patent publication”).
Various spectral sensitizing dyes have so far been used for silver halides for use in these heat-developable photosensitive materials and every endeavor has been made for attaining a higher sensitization and improving storage stability. For example, methods of using the sensitizing dyes disclosed in JP-A-2000-98525 and JP-A-2000-122206 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) are known. However, further improvement of storage stability has been required even when these sensitizing dyes are used.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-described technical problems, i.e., an object of the present invention is to provide a heat-developable photosensitive material that has a high sensitivity and is an excellent in a storage stability.
As a result of eager investigation to solve the above problems, the present inventor has found that a heat-developable photosensitive material excellent in a sensitivity and storage stability can be obtained by using as a sensitizing dye a compound having specific structure in which two or more dyes are linked by covalent bonding, thus the present invention has been accomplished.
That is, the present invention comprises the following structure:
(1) A heat-developable photosensitive material comprising:
a support;
a photosensitive silver halide;
a non-photosensitive organic silver salt;
a reducing agent for a silver ion;
a binder; and
a compound represented by formula (A):
wherein D
a
and D
b
each independently represents a dye chromophore; L
a
represents a linking group or a single bond; q
a
and r
a
each represents an integer of from 1 to 100; q
b
represents an integer of from 1 to 4; M
a
represents a counter ion for equilibrating the electric charge; and m
a
represents a number necessary to neutralize the electric charge of the molecule.
(2) The heat-developable photosensitive material as described in item (1), wherein the compound represented by formula (A) is a compound having a structure represented by formula (I):
wherein D
1
represents a dye chromophore; L
1
represents a linking group or a single bond; q
1
and r
1
each represents an integer of from 1 to 100; q
2
represents an integer of from 1 to 4; M
1
represents a counter ion for equilibrating the electric charge; and m
1
represents a number necessary to neutralize the electric charge of the molecule.
(3) The heat-developable photosensitive material as described in item (2), wherein D
1
is a dye chromophore having a structure represented by one of formulae (XI), (XII) and (XIII):
wherein L
11
, L
12
, L
13
, L
14
, L
15
, L
16
and L
17
each represents a methine group; p
11
and p
12
each represents 0 or 1; n
11
represents 0, 1, 2, 3 or 4; Z
11
and Z
12
each represents an atomic group necessary to form a nitrogen-containing heterocyclic ring, and Z
11
and Z
12
each may be a condensed ring; M
11
represents a counter ion for equilibrating the electric charge; m
1
represents a number of 0 or higher necessary to neutralize the electric charge of the molecule; and R
11
and R
12
each represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group;
wherein L
18
, L
19
, L
20
and L
21
each represents a methine group; p
13
represents 0 or 1; q
11
represents 0 or 1; n
12
represents 0, 1, 2, 3 or 4; Z
13
represents an atomic group necessary to form a nitrogen-containing heterocyclic ring; Z
14
and Z
14′
each represents an atomic group necessary to form a heterocyclic ring or an acyclic acidic terminal group together with (N—R
14
) q
11
; Z
13
, and Z
14
and Z
14′
each may be a condensed ring; M
12
represents a counter ion for equilibrating the electric charge; m
12
represents a number of 0 or higher necessary to neutralize the electric charge of the molecule; and R
13
and R
14
each represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group;
wherein L
22
, L
23
, L
24
, L
25
, L
26
, L
27
, L
28
, L
29
and L
30
each represents a methine group; p
14
and p
15
each represents 0 or 1; q
12
represents 0 or 1; n
13
and n
14
each represents 0, 1, 2, 3 or 4; Z
15
and Z
17
each represents an atomic group necessary to form a nitrogen-containing heterocyclic ring; Z
16
and Z
16
each represents an atomic group necessary to form a heterocyclic ring together with (N—R
16
)q
12
; Z
15
, Z
16
and Z
16′
, and Z
17
each may be a condensed ring; M
13
represents a counter ion for equilibrating the electric charge; m
13
represents a number of 0 or higher necessary to neutralize the electric charge of the molecule; and R
15
, R
16
and R
17
each represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group.
(4) The heat-developable photosensitive material as described in item (2), wherein the compound represented by formula (I) is a compound represented by one of formulae (XXI) and (XXII):
wherein L
11
, L
12
, L
13
, L
14
, L
15
, L
16
, L
17
, p
11
, p
12
, n
11
, Z
11
and Z
12
each has the same meaning as in formula (XI); L
2
represents a linking group; M
14
r
Hioki Takanori
Kobayashi Katsumi
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