Radiation imagery chemistry: process – composition – or product th – Color imaging process – Using identified radiation sensitive composition in the...
Reexamination Certificate
2001-05-31
2003-03-18
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Using identified radiation sensitive composition in the...
C430S448000, C430S543000, C430S544000, C430S566000, C430S955000, C430S959000
Reexamination Certificate
active
06534252
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a color photographic element comprising a common chromogenic coupler and a distinct developer associated with each color-forming unit.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,756,269 to Ishikawa et al. discloses the combination of three different developers with three different couplers. For example, a coupler “Y-1” is used with a hydrazide developing agent to form a yellow dye. Ishikawa et al. does not mention, nor attach any significance to, the fact that the same coupler is a magenta dye-forming coupler if used with a common phenylenediamine developing agent.
Clarke et al., in U.S. Pat. Nos. 5,415,981 and 5,248,739, showed that azo dyes formed from a blocked hydrazide developer are shifted to shorter wavelengths. This is perhaps not surprising since azo dyes derived from “magenta couplers” are known to be typically yellow and are used as masking couplers. The substitution pattern on the masking coupler is such that it can undergo further reaction with the oxidixed form of a paraphenylene diamine developer to form a magenta dye.
R. L. Bent et al., in
Photographic Science and Engineering
, Vol. 8, No. 3, May-June 1964 disclosed that the frequencies of maximum absorption of various dyes derived from p-phenylenediamines are closely related to the half-wave oxidation potentials of the compounds. As one point on various plotted correleations, experimental Compound A is disclosed (in Table II), in a 4-amino-N,N-dialkylaniline structure has 3,5-di-CH
3
substitution. The compounds are not disclosed as having any commercial utility and the reference might be construed as teaching that the use of Compound A would not be useful, since it would not provide the desired magenta hue with a conventional magenta coupler.
Japanese kokai JP 10090854 (1996) teaches different developers in the same color unit layer (having spectral sensitivity in the same wavelength range) in a photothermographic imaging element, in order to obtain better image or tone gradation.
U.S. Pat. No. 6,197,722 B1 to Irving et al. teaches a method of imaging, useful comprising providing an imaging member having at least one light insensitive layer comprising a catalytic center and multifunctional dye forming coupler, imagewise applying distinct developer solutions that will react with the multifunctional dye forming coupler to produce dyes of different colors. A preferred method of imagewise application of developer solution is by the technique known as “ink jet.”
PROBLEM TO BE SOLVED BY THE PRESENT INVENTION
Light-sensitive imaging elements which form yellow, magenta and cyan dye records of comparable density-forming ability and consistent stability in all three color records using conventional developers can be difficult. Cyan and yellow dye records can be a problem in this regard, especially in photothermographic elements. Accordingly, alternative ways of forming cyan or yellow dyes are especially useful in such imaging elements.
Another problem with conventional cyan dye-forming couplers relates to the fact that the raw stock stability of photographic elements is influenced by the physical properties of materials employed to formulate that element. Cyan dye-forming couplers are particularly prone to crystallization on extended cold keeping. This crystallization both degrades the image-forming ability of such an element and mars the appearance of images produced in such an element. This problem can be particularly acute in photothermographic or heat developable elements since it may be desirable to keep these elements cold before use, in order to prevent premature reaction.
Furthermore, the sharpness of the image formed in a photographic or photothermographic element follows directly from the optical properties of the element during exposure. A significant contributor to degraded optics during exposure is the thickness of the photographic element at that time. Typically, the highest molecular weight materials in photographic elements, other than the binder, are the couplers. For this reason, the thinning of imaging elements by adding couplers only after exposure could be desirable. This strategy was followed in an old KODACHROME color reversal process. However, this process was especially difficult because three distinct soluble couplers were required along with three distinct development steps.
Finally, there are numerous compounds in a color photographic imaging element, some of which compounds are quite complex and difficult to synthesize. There is an on-going endeavor to reduce the cost of manufacturing photographic elements, including eliminating or replacing more expensive compounds by less complex or more economical substitutes. The use of various couplers, for each color in a multilayer imaging system, is a relatively expensive feature in the manufacture of imaging elements.
SUMMARY OF THE INVENTION
The above-mentioned problems are solved by providing a light-sensitive silver-halide color photographic element having a common chromogenic coupler and a distinct developer associated with each color forming layer unit. Accordingly, ways of forming multiple colors from a common coupler are highly desirable in order to shorten and simplify image formation with coupler added systems.
In a first embodiment, the light sensitive silver halide color photographic element has a red-light-sensitive silver-halide layer unit and a first blocked coupling developer, a green-light-sensitive silver-halide layer unit and a second blocked coupling developer, and a blue-light-sensitive silver-halide layer unit having a third blocked coupling developer, wherein each layer unit has the same chromogenic coupler.
In a second embodiment, the light-sensitive silver-halide color photographic element has a red-light-sensitive silver-halide layer unit and a first blocked coupling developer, a green-light-sensitive silver-halide layer unit and a second blocked coupling developer, and a blue-light sensitive silver-halide layer unit having a third blocked coupling developer. In this embodiment, the common chromogenic coupler can be provided during processing of the imagewise exposed element.
DETAILED DESCRIPTION OF THE INVENTION
As mentioned above, the present invention is directed to a light sensitive silver halide color photographic element having a common chromogenic coupler and a distinct developer associated with each color forming layer unit.
In the first embodiment, the light-sensitive silver-halide color photographic element has a red-light-sensitive silver-halide layer unit and a first blocked coupling developer, a green-light-sensitive silverhalide layer unit and a second blocked coupling developer, and a blue-light-sensitive silver-halide layer unit having a third blocked coupling developer, wherein each layer unit has the same chromogenic coupler. In a preferred variant of the first embodiment, the element is a photothermographic element. In this embodiment, an imagewise exposed element is developed by heat treatment. In another variant of the first embodiment, an imagewise exposed element is developed by treatment with an acid or base, either by contacting the element to a pH controlling solution or by contacting the element to a pH controlling laminate.
In the second embodiment, the light-sensitive silver-halide color photographic element has a red-light-sensitive silver-halide layer unit and a first blocked coupling developer, a green-light-sensitive silver-halide layer unit and a second blocked coupling developer, and a blue-light-sensitive silver-halide layer unit having a third blocked coupling developer. A common chromogenic coupler is supplied to the element prior to or during a development process. In this second embodiment, the common chromogenic coupler can be supplied from solution or from a laminate sheet. Control of pH can be achieved in like manner to the first embodiment.
The common chromogenic coupler is referred to herein as a multifunctional coupler (“MFC”), by which is meant that the coupler has the property of forming different color dyes with t
Irving Lyn M.
Szajewski Richard P.
Eastman Kodak Company
Konkol Chris P.
Letscher Geraldine
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