Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-05-04
2004-02-17
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S583000, C430S588000, C430S576000
Reexamination Certificate
active
06692905
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a spectrally sensitized silver halide photographic emulsion and a photographic material using the same.
BACKGROUND OF THE INVENTION
Great efforts have hitherto been made to increase the sensitivity of silver halide photographic materials. In silver halide photographic emulsions, sensitizing dyes adsorbed onto surfaces of silver halide grains absorb light incident on photographic materials, and transmit its light energy to the silver halide grains, thereby giving light sensitivity. Accordingly, in spectral sensitization of silver halides, it is conceivable that the light energy transmitted to the silver halides can be increased by increasing the light absorptivity of the silver halide grains per unit grain surface area, thus achieving an increase in spectral sensitivity. Improvement in the light absorptivity of the surfaces of the silver halide grains only requires an increase in the adsorption of the spectral sensitizing dyes per unit grain surface area.
However, the adsorption of the sensitizing dyes onto the surfaces of the silver halide grains have a limitation, and it is difficult to allow more dye chromophoric groups than those in monolayer saturated adsorption (namely, one layer adsorption) to be adsorbed. In the present state, therefore, the absorptivity of incident light quanta of the individual silver halide grains in a spectral sensitizing region is still low.
For solving such problems, the following proposals have been submitted.
P. B. Gilman, Jr. et al. allowed a cationic dye to be adsorbed by a first layer, and further allowed an anionic dye to be adsorbed by a second layer using an electrostatic force in
Photographic Science an Engineering,
20 (3), 97 (1976).
G. B. Bird et al. allowed a plurality of dyes to be adsorbed onto a silver halide in multiple layers to sensitize it by contribution of Forster type excitation energy transfer in U.S. Pat. No. 3,622,316.
Sugimoto et al. conducted spectral sensitization by the transfer of energy from a luminous dye in JP-A-63-138341 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and JP-A-64-84244.
R. Steiger et al. tried spectral sensitization by the transfer of energy from a gelatin-substituted cyanine dye in
Photographic Science and Engineering,
27 (2), 59 (1983).
Ikekawa et al. conducted spectral sensitization by the transfer of energy from a cyclodextrin-substituted dye in JP-A-61-251842.
Further, Richard Burton et al. allowed a cationic dye and an anionic dye to be adsorbed in multiple layers, and tried to increase the sensitivity by the transfer of energy from the dye in a second layer to the dye in a first layer in EP-A-0985964, EP-A-0985965, EP-A-0985966 and JP-A-0985965.
In these methods, however, the sensitizing dyes were actually insufficiently adsorbed in multiple layers by the surfaces of the silver halide grains, so that the effect of increasing the sensitivity was very little. It has been therefore demanded that the interaction among dye molecules are enhanced to realize substantially effective adsorption in multiple layers.
On the other hand, when the sensitizing dyes are adsorbed on the grain surfaces in multiple layers, the grains have been proved to easily aggregate in some cases because the adsorption of gelatin is decreased to lower protective colloid ability. Accordingly, a technique for allowing the sensitizing dyes to be adsorbed in multiple layers and inhibiting aggregation of the grains has been desired.
We have already discovered a method of using aromatic group-containing dyes, or aromatic group-containing cationic dyes in combination with anionic dyes, as one method for achieving this object, wherein these dyes are described in JP-A-10-239789, JP-A-8-269009, JP-A-10-123650 and JP-A-8-328189. However, this method has problems with regard to increased dye residual color after processing, compared with conventional sensitizing dyes, and keeping quality (i.e., storage stability), because the cationic dyes high in hydrophobicity are used as the sensitizing dyes.
SUMMARY OF THE INVENITON
It is therefore an object of the present invention to provide a silver halide photographic emulsion inhibiting aggregation of grains and high in sensitivity.
Another object of the present invention is to provide a silver halide photographic material using the same, particularly a silver halide photographic material in which dye residual color after processing is inhibited.
Methine dyes used in the present invention are expected to be useful for other photoelectronic functional materials, as well as the silver halide photographic materials.
Such methine dyes are:
(1) A methine dye compound having at least one group represented by the following formula (I) or (II) in a molecule thereof:
X—H (I)
wherein X represents an atom electrically more negative than a carbon atom,
Y (II)
wherein Y represents an atom electrically more negative than a carbon atom, and has one or more lone electron pairs;
(2) A methine dye compound having at least two groups selected from the group consisting of groups represented by the above formulas (I) and (II) in a molecule thereof;
(3) A methine dye compound having in a molecule thereof at least one atomic group in which at least two groups selected from the group consisting of groups represented by the above formulas (I) and (II) are adjacent to each other or adjacent to each other through a carbon atom or another atom;
(4) A methine dye compound having in a molecule thereof at least one atomic group in which at least three groups selected from the group consisting of groups represented by the above formulas (I) and (II) are adjacent to each other or adjacent to each other through a carbon atom or another atom;
(5) The methine dye compound described in the above (4), wherein the atomic group is other than an atomic group represented by the following formula (III), (IV) or (V):
(6) A methine dye compound having in a molecule thereof at least one atomic group in which at least four groups selected from the group consisting of groups represented by the above formulas (I) and (II) are adjacent to each other or adjacent to each other through a carbon atom or another atom;
(7) The methine compound described in any one of (1) to (6), which further has in a molecule thereof at least one aromatic group not conjugated with a dye chromophoric group;
(8) The methine compound described in any one of (1) to (7), which has a basic nucleus obtained by cyclocondensation of three or more rings;
(9) The methine compound described in any one of (1) to (8), which is a cyanine dye;
(10) The methine compound described in (9), wherein the atomic group containing at least one group represented by formula (I) or (II) described in any one of (1) to (6) is contained in a group substituted at the N-position;
(11) The methine compound described in (9), wherein the atomic group containing at least one group represented by formula (I) or (II) described in any one of (1) to (6) is contained in a nucleus substituent group; and
(12) The methine compound described in (9), wherein the atomic group containing at least one group represented by formula (I) or (II) described in any one of (1) to (6) is contained in a group substituted at the meso-position.
According to the present invention, there are provided:
(13) A silver halide photographic emulsion comprising at least one methine dye compound described in any one of the above (1) to (12);
(14) A silver halide photographic emulsion which is spectrally sensitized with at least one kind of sensitizing dye having a site which can form three or more complementary hydrogen bonds between molecules of a single or more kinds of dyes;
(15) The silver halide photographic emulsion described in (14), wherein at least one kind of sensitizing dye having a site which can form three or more complementary hydrogen bonds between molecules of a single or more kinds of dyes used in the silver halide photographic emulsion described in the above (14) is positioned in a near
Hioki Takanori
Kobayashi Katsumi
Fuji Photo Film Co. , Ltd.
Letscher Geraldine
Sughrue & Mion, PLLC
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