Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
2000-09-12
2002-05-14
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
Reexamination Certificate
active
06387607
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a compact photographic color developer concentrate composition comprising a concentrate and a solid component for use in color photographic development of silver halide photographic sensitizing material and a method for processing image-wise exposed silver halide photographic sensitizing materials using the developer concentrate composition.
B. Description of the Related Art
Exposed photographic color silver halide emulsions are generally processed through the steps of color development, de-silvering, washing and stabilization, usually using the following processing solutions: color developer, bleaching solution, fixer, wash water and stabilizing solution. These processing solutions are either prepared from solid chemicals, multi-part liquid concentrates, or diluted, single-part, ready-to-use solutions.
There is a need in the photographic processing industry to reduce the number of multiple liquid concentrates necessary for the preparation of working solutions and replenisher solutions, thus improving the compactness of required materials. At the same time, the long term stability of the materials must be maintained.
For the developer processing step, sets of multiple liquid concentrates are used to prepare the developer replenisher and working strength developer by mixing the liquid concentrates and diluting them with water. This process has found wide-reaching commercial success within the photographic processing industry. A majority of the commercially available photographic processing equipment is based on this system.
In the case of color developers, multiple liquid concentrate parts are necessary due to chemical reactions that occur between hydroxyl amine (HA) and derivatives thereof and p-phenylenediamine and derivatives and salts thereof and the sulfite preservative commonly used when stored together in liquid form. If these chemicals are incorporated into a concentrated solution, the chemical reaction between them proceeds rapidly, severely shortening the shelf life of the composition. Thus, a single concentrated solution that has hydroxyl amine, sulfite preservative and p-phenylenediamine heretofore has not been possible.
In an effort to reduce the number of parts of the developer concentrate, the industry has investigated the use of alternative developer forms and formulations. For example, Abe (U.S. Pat. No. 5,837,435) teaches the use of limited hydroxylamine derivatives in a concentrated solution. However, photographic performance with these derivatives on certain films can produce variations when compared to using hydroxylamine sulfate. In addition, Abe is limited in specific gravity range, thereby not providing compact concentrates.
Kleinschmidt, DE 3106775, discloses a single-part liquid color photographic developer concentrate. However, this developer concentrate requires organic solvents for dissolution to form a replenisher or working developer solution. These solvents also can produce variations on certain films.
Ishida and Koboshi (U.S. Pat. No. 5,480,768) propose the use of solid tablets of chemicals to prevent the chemical interactions that occur in liquid concentrates. Preferably, each chemical should be in the form of a tablet, necessitating the dissolution of multiple tablets to form a developer solution. Using solid tablets of chemicals results in a low dissolution speed of the chemicals in the replenisher or working strength developer. Thus, it is necessary to use water warmed up to around 40° C. to speed dissolution. Warm water-supplying equipment and agitation equipment are required, making solid tablets very difficult to handle in small-scale processing stores (mini- or micro-laboratories). Thus, the solid tablets are disadvantageous because they require special handling and mixing equipment not common in the photographic industry, as opposed to existing processors that allow pourable concentrates to be mixed with water. Because of these disadvantages, the use of tablets has not become widespread within the photographic industry.
Yamashita and Ueda (EP 640,872) also teach a solid photoprocessing composition in the form of a coated tablet. The tablet is coated with one or more of polyalkylene glycol, mono- and di-saccharides or vinyl polymer having a betaine structure to resist abrasion and deterioration. Due to the slow dissolution speed of the tablet coating, the tablets must be added directly to the working solution, again requiring special handling and mixing equipment. In addition, there are many photographic processing chemical components known in the art that are available only as liquids that are excluded from use by this method.
There is a continuing need in the industry to produce a more compact, color developer concentrate that is stable, pourable, easily dissolved, readily mixed in existing photographic processing equipment to prepare both replenisher and working strength developer solutions, and has improved photographic performance and environmental impact, such as using less packaging material thereby reducing the discharge of waste to the environment.
SUMMARY OF THE INVENTION
The present invention provides a stable, pourable photographic developer concentrate composition comprising a concentrate and a solid component. The developer concentrate composition can be used in existing mixing and processing equipment without modification. Further, the developer concentrate composition, concentrate and solid can be formulated using existing and readily available chemicals necessary for photographic processing.
The present invention further provides a single developer concentrate composition in which a concentrate and a solid co-exist or are in contact with each other within the same container. The solid is coated with, or encapsulated in, a material that is insoluble in the concentrate of the developer concentrate composition but is readily and completely soluble when the developer concentrate composition is diluted with water to prepare a replenisher or working strength developer. The developer concentrate composition has excellent storage stability even for extended periods of time at high temperature because chemical components known to react with each other in liquid form are present within the same container without reacting.
In a preferred embodiment, the invention comprises a color developer concentrate composition of a concentrate comprising water and at least one color developer chemical component and a solid comprising at least one color developer chemical component, wherein the solid is isolated from the concentrate by a coating insoluble in the concentrate but readily soluble when diluted with water to prepare a replenisher or working strength developer. Preferably, the concentrate and solid are present in one container. More preferably, the coating comprises an alkali metal sulfate.
In preferred embodiments, the concentrate comprises one or more of a color developer chemical selected from hydroxylamine or a derivative thereof, p-phenylenediamine or a derivative or salt thereof and sulfite. Preferably, the color developer chemical is one or more of a hydroxylamine derivative and sulfite.
In other preferred embodiments, the solid comprises one or more of a color developer chemical selected from hydroxylamine or a derivative thereof, p-phenylenediamine or a derivative or salt thereof and sulfite. Preferably, the color developer chemical is one or more of hydroxylamine or a derivative thereof, more preferably hydroxylamine sulfate, and p-phenylenediamine or a derivative or salt thereof.
In another embodiment, a solid comprises a color developer chemical component comprising at least one color developer chemical suitable for developing silver halide photosensitive materials, and a coating, wherein the coating is insoluble in the concentrate of the developer concentrate composition and is soluble when dissolved with water to prepare a replenisher or working strength developer. In a preferred embodiment, the coating comprises an alkali metal sulfa
Abe Akira
Chen Yue
Fuji Hunt Photographic Chemicals Inc.
Le Hoa Van
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