Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
1999-08-09
2003-02-25
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S569000
Reexamination Certificate
active
06524782
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for preparing a silver halide emulsion used in silver halide photographic light sensitive materials, and a silver halide photographic light sensitive material by the use of the silver halide emulsion.
BACKGROUND OF THE INVENTION
Recently, reduction of processing effluent of silver halide photographic light sensitive materials (hereinafter, also denoted simply as photographic materials) from the viewpoint of environment protection and saving space. As means for reducing the processing effluent has been known reduction of the silver coating weight of a photographic material so as to enable to process the photographic material at low replenishing rates. However, simply reducing the silver coating weight resulted in reduction in an optical density or sensitivity, so that the use of tabular silver halide grain emulsions has been known in the photographic art.
There have been disclosed methods for preparing tabular silver halide grains (hereinafter, also denoted simply as tabular grains) and techniques of using the tabular grains, as described in U.S. Pat. Nos. 4,434,226, 4,439,520, 4,414,310, 4,434,048, 4,414,306 and 4,459,353; JP-A 59-99433 and 62-20944 (herein, the term, JP-A means a unexamined and published Japanese Patent Application). It is well known that tabular grains have advantages, such as enhanced sensitivity including enhanced spectral sensitization efficiency due to a sensitizing dye, improvements in sensitivity/granularity ratio, enhanced sharpness due to a specific optical property of the tabular grains and enhanced covering power. On the other hands, tabular grains have a disadvantage such that pressure defect easily occurs due to thin thickness of the tabular grains. In rapid processing for use in clinical photography by using an automatic processor, for example, pressure defects in wet state, which is called roller marks and caused by transporting rollers of the processor in a processing solution, easily occur. As a technique for enhancing pressure resistance is known a technique of allowing metals of the 8th group of the periodical table to be doped in the interior of tabular grains. It was proved that it was unexpectedly difficult to allow such metals to be occluded in a desired position within the tabular grain, leading to reduced sensitivity and enhanced fogging.
Designation of rapid processable photographic materials with tabular grains by decreasing the coating weight of binder and silver resulted in such a defect that uneven development easily occurred.
Hardeners are conventionally contained in a developer for use in rapid access. The hardeners are such aldehyde types as glutar aldehyde, which are apprehensive for not only order but also effects on human body. Recently, concerns about environmental matter increase so that urgent improvements desired. However, rapid processing with a developer containing no hardener resulted in not only marked deterioration in roller marks and uneven development, but also processing fault, such as dye stain due to sensitizing dyes remaining in the photographic material.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a method for preparing a silver halide tabular grain emulsion, which exhibits high sensitivity and produces no roller mark even when subjected to rapid processing at low replenishing rates, and a silver halide photographic material in which uneven development and stain due to remained sensitizing dye, even when developed in a developer containing no hardener.
The object of the present invention described above can be accomplished by the following constitution:
a method of preparing a silver halide emulsion, wherein said silver halide emulsion comprises tabular grains exhibiting a mean equivalent circle diameter of 0.1 to 10.0 &mgr;m, a mean grain thickness of 0.01 to 0.3 &mgr;m and an aspect ratio of 1.5 to 300, the method comprising:
(a) reacting a silver salt solution and a halide salt solution to perform silver halide grain nucleation, followed by silver halide grain growth to form the tabular grains, wherein the tabular grains are formed in the presence of fine silver halide grains containing at least one selected from the group of gallium, indium and metals in Groups 8, 9 and 10 of the periodical table;
the method further comprising:
(b) removing a solution containing soluble salts from a reaction mixture solution by ultrafiltration during the silver halide grain growth to reduce the volume of the reaction mixture solution in a reaction vessel.
DETAILED DESCRIPTION OF THE INVENTION
The tabular silver halide grains according to the present invention are prepared in the presence of fine silver halide grains containing at least one selected from the group consisting of gallium, indium and atoms in Group 8, 9 and 10 of the periodical table, including their ions or complexes.
Preparing tabular silver halide grains in the presence of the fine silver halide grains means that at least one selected from the group consisting of gallium, indium, and atoms in Group 8, 9 and 10 of the periodical table or their ions or complexes has been allowed to be contained (or doped) in fine silver halide grains, and using the fine silver halide grains, the metal-doping into the tabular grains is performed.
The metals of gallium, indium, Group 8 (Fe, Ru, Os), Group 9 (Co, Rh, Ir) and Group 10 (Ni, Pd, Pt) in the form of an atom, ion or complex ion (hereinafter, Groups 8, 9 and 10 are also collectively referred to as Group VIII).
Compounds contained in the fine silver halide grains are preferably metal complexes comprised of a metal ion of the Group VIII and ligand(s). In specific, preferred form, it is contemplated to employ as a dopant a hexacoordinate metal complex satisfying the following formula:
[MeL
6
]
n
wherein Me is filled frontier orbital polyvalent metal ion, preferably, Fe
+2
, Ru
+2
, Os
+2
, Co
+3
, Rh
+3
, Ir
+3
, Pd
+4
or Pt
+4
; L
6
represents six coordinate complex ligands which can be independently selected, provided that at least four of the ligands are anionic ligands and at least one (preferably at least three and more preferably at least four) of the ligands is more electronegative than any halide ligands; and n is −2, −3 or −4. More preferably, the ligands represented by L
6
contain one to six CN
−
.
Specific examples of dopants capable of providing shallow electron traps are shown below:
SET-1
[Fe(CN)
6
]
4-
SET-2
[(Ru(CN)
6
]
4-
SET-3
[(Os(CN)
6
]
4-
SET-4
[Rh(CN)
6
]
3-
SET-5
[Ir(CN)
6
]
3-
SET-6
[Fe(hydrazine)(CN)
5
]
4-
SET-7
[RuCl(CN)
5
]
4-
SET-8
[OsBr(CN)
5
]
4-
SET-9
[RhF(CN)
5
]
4-
SET-10
[IrBr(CN)
5
]
3-
SET-11
[FeCO(CN)
5
]
3-
SET-12
[RuF
2
(CN)
4
]
4-
SET-13
[OsCl
2
(CN)
4
]
4-
SET-14
[RhI
2
(CN)
4
]
4-
SET-15
[IrBr
2
(CN)
4
]
4-
SET-16
[Ru(CN)
5
(OCN)]
4-
SET-17
[Ru(CN)
5
(N
3
)]
4-
SET--18
[Os(CN)
5
(SCN)]
4-
SET--19
[Rh(CN)
5
(SeCN)]
3-
SET-20
[Ir(CN)
5
(HOH)]
2-
SET-21
[Fe(CN)
3
Cl
3
]
3-
SET-22
[Ru(CO)
2
(CN)
4
]
2-
SET-23
[Os(CN)Cl
5
]
4-
SET-24
[Co(CN)
6
]
3-
SET-25
[Ir(CN)
4
(oxalate)]
3-
SET-26
[In(NCS)
6
]
3-
SET-27
[Ga(NCS)
6
]
3-
It is additionally contemplated to employ oligomeric coordinate complexes in a silver halide emulsion to increase sensitivity, as taught by Evans et al. U.S. Pat. No. 5,024,931.
The dopants are effective in conventional concentrations, where concentrations are based on the total silver of finally formed tabular silver halide grains. Preferably dopants are contemplated to be incorporated in concentrations of at least 1×10
−6
mol per silver mol up to their solubility limit, typically not more than 5×10
−4
mol per silver mol. Specifically preferred concentrations are in the range
Baxter Janet
Bierman Jordan B.
Bierman, Muserlian and Lucas
Konica Corporation
Walke Amanda C.
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