Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
1998-01-26
2004-05-04
Huff, Mark F. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S567000
Reexamination Certificate
active
06730467
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a silver halide photographic light-sensitive material, hereinafter referred to as a light-sensitive material. The invention particularly relates to photographic light-sensitive material which is high in sensitivity and excellent in both gradation and wet pressure resistance.
BACKGROUND OF THE INVENTION
In recent years, there has been demand for a light-sensitive material which is high in image quality, excellent in processing stability and inexpensive in cost and, in particular, for a light-sensitive material capable of being rapidly processable.
To be more specific, an automatic processor is installed at a photofinishing laboratory to process light-sensitive materials. One of the services given to customers is the return of finished films and prints on the same day the photofinishing orders are received and, quite recently, to return them within several hours after receiving the finishing orders, therefore the developments of more rapidly processable light-sensitive materials has been urgently required.
On the other hand, there have been increased instances where light-sensitive materials are liable to mechanical pressure when they are treated in equipment such as printers and automatic processors. When a light-sensitive material is applied with various pressures as mentioned above, the silver halide grains of the light-sensitive material are also applied with a pressure through the binders. i.e., gelatin of the silver halide grains. When the silver halide grains are applied with a pressure, the photographic characteristics of the light-sensitive material are also varied in such a phenomenon as pressure desensitization, pressure fog or the like. Particularly in the case of a rapid processing, the light-sensitive material is liable to a stronger pressure because it is transported faster. This phenomenon has been far well-known as a photographic pressure effect and is described in, for example, T. H. James, “The Theory of Photographic Process” 4th Ed., Macmillan Publishing Co., New York, Paragraph 24; D. Dautrich, F. Granzer and E. Moisar, “Journal of Photographic Science”, 21, p. 221, 1973.
Light-sensitive materials are applied with pressure in two cases. i.e., in dried conditions and in wet conditions in which a developing process is being carried out.
Accordingly, there have been attempts to provide light-sensitive materials having more stability against pressure. For example, they are disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 53-13923/1978, a high boiling solvent is contained in an amount of not less than 20% by weight of the binders thereof in a coupler-containing layer; in Japanese Patent Publication No. 57-12133/1982, a coupler and a conversion emulsion are used; in British Patent No. 738,618, a heterocyclic compound is used; in U.S. Pat. No. 2,960,404, a polyhydric alcohol is used; and so forth. However, a fully satisfactory effect has not been obtained from the above-disclosed techniques.
Further Japanese Patent O.P.I. Publication No. 62-250437/1987 discloses a method that a light-sensitive material, which is comprised of a silver halide mainly composed of silver chloride and a water-soluble iridium compound, is hardened with a specific layer hardener. It was, however, found that such a light-sensitive material is still not satisfactory, some effects may be obtained on pressure resistance in wet conditions though, but is still not improved in the pressure resistance in dry conditions and is too low in sensitivity and too soft in contrast to be applied suitably to rapid processing.
Further U.S. Pat. No.4,962,016 discloses a method that a light-sensitive material, which is comprised of a silver halide mainly composed of silver chloride that is added with elemental sulfur. The term “elementary sulfur” used in that invention, means so-called single element sulfur which is not a form of compound with any other elements. In that invention, therefore, the elemental sulfur does not include any sulfur-containing compounds which are known as the photographic additives in the art. It was found that such a light-sensitive material is satisfactory, some effects may be obtained on pressure resistance both for wet and dry conditions.
PROBLEM TO BE SOLVED BY THE INVENTION
There remains a need for photographic materials that have increased resistance to defects caused by pressure on the photographic material during the developing process. There is also a need for light-sensitive materials that have improved resistance to pressure defects caused by handling prior to developing.
SUMMARY OF THE INVENTION
It is an object of the invention to solve the above-mentioned problems of the prior art so as to provide silver halide photographic light-sensitive material having a high sensitivity, an excellent gradation and an excellent pressure resistance.
These and other objects of the invention are generally accomplished by a method of forming a silver halide emulsion comprising forming a silver chloride emulsion, adding spectral sensitizing dye, sulfur, and gold sulfide to said emulsion, heating said emulsion to chemically and spectrally sensitize said emulsion, and cooling said emulsion.
ADVANTAGEOUS EFFECT OF THE INVENTION
The process of chemical/spectral sensitization of this invention, as described and claimed hereinafter, provides a very effective solution to the problem of pressure sensitivity of high chloride emulsions.
DETAILED DESCRIPTION OF THE INVENTION
This invention can be achieved with a silver halide photographic light-sensitive material comprising a support bearing thereon a photographic component layer including a silver halide emulsion layer, wherein the silver halide emulsion is sensitized with gold-sulfide in the presence of sulfur. The term “sulfur” used in this invention refers to the single substance of sulfur which may or may not be in the form of a compound with any other elements. In this invention, therefore, the “sulfur” includes any sulfur-containing compounds which are known as the photographic addititives in the art, such as a sulfide, sulfuric acid and the salts thereof, sulfurous acid and the salts thereof, thiosulfuric acid and the salts thereof, sulfonic acid and the salts thereof, thioether compounds, thiourea compounds, mercapto compounds, sulfur-containing heterocyclic compounds, and so forth. In this invention, the “sulfur” also includes any sulfur-donating compounds that are applicable for the practice of this invention. Examples of such are those described in U.S. Pat. Nos. 5,443,947 and 5,292,635 that are hereby incorporated by reference. A preferred source of sulfur is sodium thiosulfate, as this material provides very good resistance to pressure in the photographic elements formed using emulsions formed by the method of the invention.
The sulfur of the invention may be present in any suitable amount. The sulfur suitably is present in an amount between 0.05 and 20 mg/silver mole. A preferred amount of sulfur is between 0.1 and 3 mg/silver mole. The preferred sodium disulfide is suitably present in an amount between about 0.5 and 20 mg/silver mole. A preferred amount of the sodium disulfide is between 0.1 and 1.0 mg/silver mole for effective sensitization at low cost.
The invention may be practiced with any of the known techniques for emulsion preparation. Such techniques include those which are normally utilized, for instance single jet or double jet precipitation; or they may include forming a silver halide emulsion by the nucleation of silver halide grains in a separate mixer or first container with later growth in a second container. All these techniques are referenced in the patents discussed in
Research Disclosure
, December 1989, 308119, Sections I-IV at pages 993-1000.
The dispersing medium contained in the reaction vessel prior to the nucleation step is comprised of water, the dissolved chloride ions and a peptizer. The dispersing medium can exhibit a pH within any convenient conventional range for silver
Klaus Roger L.
Mydlarz Jerzy Z.
Blank Lynne M.
Huff Mark F.
Leipold Paul A.
Walke Amanda C.
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