Sensitizing dye and silver halide photographic material

Details Sensitizing dye and silver halide photographic material Sensitizing dye and silver halide photographic material

2002-04-10

2004-01-13

Le, Hoa Van (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

Reexamination Certificate

active

06677113

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an infrared-sensitizing dye and infrared-sensitive photographic materials by the use thereof and in particular to a photographic material and a thermally developable photothermographic material by the use of an infrared-sensitive silver halide emulsion exhibiting a high sensitivity, a low fog and reduced variation in sensitivity following storage.
BACKGROUND OF THE INVENTION
There are known silver halide photographic light sensitive materials employing silver halide grains and photo-recording materials employing photopolymerization or cleavage reaction. However, the longest photosensitivity edge of the silver halide grains is in the vicinity of 500 nm and the photosensitivity region of photopolymers is in a ultraviolet region so that spectral sensitization by use of dyes is indispensable to provide sensitivity at the loner wavelength side. Particularly with recent progress in light sources, importance of photosensitive materials sensitive to the laser wavelength region increases in the field of recording materials for industrial use. Further in the field of picture-taking photosensitive materials are noted infrared photosensitive materials used for recording environment information and superior in portrayability.
There are known a number of compounds as a sensitizing dye or spectral sensitizing dye, including cyanine dyes and merocyanine dyes described in T. H. James “The Theory of the Photographic Process” Fourth ed. (1977, Macmillan Co. N.Y.) pages 194-234; F. M. Hammer “The Cyanine Dyes and Related Compounds” (1964, John Wiley & Sons, N.Y.); D. M. Sturmer “The Chemistry of Heterocyclic Compounds” vol. 30, page 441 (1977, John Wiley & Sons, N.Y.); JP-A 3-138638, 3-163440, 5-72660, 5-72661, 5-88292, 8-194282, 9-166844, 9-281631, 9-282672, 9-292673 and 10-73900 (hereinafter, the term, JP-A means a unexamined and published Japanese Patent Application); U.S. Pat. Nos. 2,320,439, 2,398,999, 2,734,900, 3,582,344, 4,536,473, 4,740,455, 4,835,096, and 5,393,654; British Patent 774,779, 625,245, and 895,930; European Patent 420,012 and 821,811.
These sensitizing dyes and spectral sensitizing dyes are required not only to expand spectral sensitivity region but also to satisfy the following conditions:
1) optimum spectral sensitization region,
2) high spectral sensitization efficiency (sensitivity),
3) no unfavorable interaction with other additives such as a stabilizer, antifoggant, coating aid, high boiling solvent and binder,
4) no adverse effect on the characteristic curve such as fogging or contrast variation,
5) no variation in photographic performance such as reduction in a S/N ratio or sensitivity when the dye containing photosensitive material is aged (particularly when aged at a high temperature or high humidity),
6) no diffusion of an added sensitizing dye to a different photosensitivity layer, causing color mixing, and
7) removal or discoloration of the dye after development, fixing and washing, causing no color stain.
However, commonly known spectrally sensitizing dyes have not satisfied these conditions to sufficiently satisfactory levels. Specifically, photosensitive materials to be recorded by using a laser light source are desired to have a high absorption fitted to the bright line wavelengths. However, a dye having an absorption in the region of red to infrared contains a long conjugated chain and is so susceptible to environments that although exhibiting a high molar extinction coefficient in a solution, phenomena easily occur such that the dye discolors during the preparation process or causes a number of conformational changes, forming a broad absorption spectrum exhibiting a low absorption maximum. Further, the energy gap between the lowest unoccupied level and the highest occupied level is so narrow that the lowest unoccupied level and the highest occupied level are close to the conduction band level of silver halide grains, producing problems that fogging easily occur or sensitivity is reduced.
Accordingly, there are desired an infrared-sensitive recording material exhibiting high sensitivity in the region of red to infrared and further an infrared sensitive recording material exhibiting high sensitivity and low fog and reduced variation in performance even when being aged.
Infrared sensitizing dyes generally exhibit a lower adsorption to silver halide grains than dyes sensitizing to the visible region, producing problems such as low sensitivity or marked desensitization during pre-exposure storage during standing in the form of a solution in the process of preparing a coating solution. There have been made various attempts of overcoming these problems by varying the structure of the dye. However, disclosed dyes have not yet reached levels solving the problems.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an image forming composition exhibiting a high sensitivity to infrared laser light exposure and an image forming method by the use thereof, and in particular an infrared sensitive silver halide emulsion exhibiting a high sensitivity and low fog and superior in storage stability, a silver halide photographic light sensitive material and thermally developable photosensitive material containing the emulsion and an image forming method by the use of the materials.
An object of the invention is to provide a thermally developable photosensitive material exhibiting a high sensitivity and reduced desensitization during pre-exposure storage and preparation method thereof.
An object of the invention is to provide a thermally developable photosensitive material exhibiting little variation in photographic performance even when a standing time of a photosensitive solution is extended during the preparation thereof, in particular, a preparation method of the photosensitive solution and a coating method thereof.
An object of the invention is to provide an image recording method and image forming method by use of a thermally developable photosensitive material accomplishing the objects described above.
The above objects of the invention can be accomplished by the following constitution:
1. A spectral sensitizing dye represented by the following formulas (1) to (4):
wherein Y
1
, Y
2
and Y
11
each are independently an oxygen atom, a sulfur atom, a selenium atom, —C(Ra)(Rb)— group or —CH═CH— group, in which Ra and Rb each are a hydrogen atom, a lower alkyl group or an atomic group necessary to form an aliphatic spiro ring between Ra and Rb; Z
1
is an atomic group necessary to form a 5- or 6-membered ring; R is a hydrogen atom, a lower alkyl, a cycloalkyl group, an aralkyl group, a lower alkoxy group, an aryl group, a hydroxy group or a halogen atom; W
1
, W
2
, W
3
, W
4
, W
11
, W
12
, W
13
and W
14
each are independently a hydrogen atom, a substituent or a non-metallic atom group necessary to form a condensed ring by bonding between W
1
and W
2
or W
11
and W
12
; R
1
and R
11
are each an aliphatic group or a non-metallic atom group necessary to form a condensed ring by bonding between R
1
and W
3
or R
11
and W
14
; V
1
to V
9
, and V
11
to V
13
each are independently a hydrogen atom, a halogen atom, an amino group, an alkylthio group, an arylthio group, a lower alkyl group, a lower alkoxy group, an aryl group, an aryloxy group, a heterocyclic group or a non-metallic atom group necessary to form a 5- to 7-membered ring by bonding between V
1
and V
3
, V
2
and V
4
, V
3
and V
5
, V
2
and V
6
, V
5
and V
7
, V
6
and V
8
, V
7
and V
9
, or V
11
and V
13
, provided that at least one of V
1
to V
9
and at least one of V
11
to V
13
are a group other than a hydrogen atom; X
1
and X
11
each are an ion necessary to compensate for an intramolecular charge; 11 and 111 each an ion necessary to compensate for an intramolecular charge; k1 and k2 each are 0 or 1; p1 and p11 are each 0 or 1; q1 and q11 each are 1 or 2, provided that the sum of p1 and q1 and the sum of p11 and q11 are respectively not more than 2;
wherein Y
21
, Y
22
and Y
31
each are independ

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