Radiation imagery chemistry: process – composition – or product th – Thermographic process – Heat applied after imaging
Reexamination Certificate
2002-10-25
2004-06-08
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Thermographic process
Heat applied after imaging
C430S021000, C430S339000, C430S345000, C430S351000, C430S353000, C430S510000, C430S513000, C430S531000, C430S559000, C430S566000, C430S620000
Reexamination Certificate
active
06746830
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a silver halide photosensitive material comprising a heat-responsive-discolorable coloring composition capable of rapidly forming high-quality image excellent in sharpness, color reproducibility and optical readability, and a method for forming image using the heat-responsive-discolorable coloring composition.
BACKGROUND OF THE INVENTION
To absorb a particular wavelength, a photosensitive silver halide emulsion layer, etc. of a photosensitive material is sometimes colored. For instance, when the spectroscopic composition of a light entering into a silver halide emulsion layer is controlled, a coloring layer is formed farther than the emulsion layer of the photosensitive material from a substrate. Such a coloring layer is also called “filter layer.” When there are a plurality of photographic emulsion layers like a multi-layer color photosensitive material, the filter layer may be located between them.
A light scattered during passing through the emulsion layer or after penetrating the emulsion layer may be reflected on an interface between the emulsion layer and the substrate or a surface of the photosensitive material on the opposite side of the emulsion layer, and enters into the emulsion layer again, causing the blurring of image, called “halation.” To prevent this halation, a coloring layer called “antihalation layer” is formed between the emulsion layer and the substrate, or on a surface of the substrate opposite to the emulsion layer side. In the case of the multi-layer color photosensitive material, an antihalation layer may also be formed between each set of adjacent layers.
These coloring layers are necessary only at the time of exposure, and unnecessary thereafter. Particularly when image information obtained on the photosensitive materials is read by a scanner, the existence of absorption by the coloring layer at a reading wavelength necessitates the reading of high-concentration information, resulting in the generation of noises. Accordingly, at least a part of the coloring layer is preferably discolored, namely its color is removed. Though discoloration can be carried out after exposure in the conventional, wet-treatment-type, photosensitive materials, such treatment cannot be conducted in a dry treatment, and thus the coloring layer should be discolored by other means.
With respect to discoloration of a coloring layer, several methods were proposed, and main methods among them are:
(1) Methods using a coloring layer comprising heat-decolorable dyes (U.S. Pat. Nos. 3,769,019, 3,821,001, 4,033,948, 4,088,497, 4,153,463 and 4,283,487, JP 52-139136 A, JP 53-132334 A, JP 54-56818 A, JP 57-16060 A and JP 59-182436 A, etc.), or dyes decolored by corrosive gases generated from counter salts while heating (U.S. Pat. No. 4,347,401, etc.), as an antihalation layer;
(2) Methods for discoloration of a coloring layer when heated in the presence of agents for generating carbanions by heating and dyes in the coloring layer (U.S. Pat. Nos. 5,135,842, 5,258,274, 5,314,795, 5,324,627 and 5,384,237, EP 605 286 B, JP 6-222504 A and JP 7-199409 A);
(3) Methods using dyes comprising leuco dyes and acids vaporizable or decomposable by heating for generating a color-developed state by their combination in an antihalation layer or a filter layer (JP 10-16410 A and JP 10-287055 A);
(4) Methods using a coloring layer comprising dyes discolored by light, such as an o-nitroarylidene dye or an o-nitro-o-azarylidene dye (U.S. Pat. Nos. 3,984,248 and JP 54-17833 A), dyes having cleavable N—O bonds (U.S. Pat. No. 3,770,451), chrominium-type cyanine dyes (JP 2-229864 A), anionic dyes containing iodonium salts as counter ions (JP 59-164549 A), etc., as an antihalation layer; and
(5) Methods using a coloring layer comprising both (a) photosensitive halogen-containing compounds (JP 57-20734 A and JP 57-68831 A), azide compounds (JP 63-146028 A), ketone-based sensitizing compounds (JP 50-10618 A), mesoionic compounds (U.S. Pat. No. 4,548,895) or iodonium compounds (U.S. Pat. No. 4,701,402), and (b) dyes which are decolored by reaction with active species generated by irradiating and/or heating the above compounds, or by interaction with the above compounds in excited states.
The above methods (1) to (3) are easy because discoloration occurs when heated. However, a discoloration reaction is likely to occur during storage in these methods, failing to exhibit functions when necessary. For example, non-professional photographers often store photographic photosensitive materials under such a hard condition as in a car in the middle of summer, making it likely that the coloring layers of the photographic photosensitive materials are decolored by heat before their use. It has also been found that in a case where a reaction accompanied with gas generation at the time of heating is utilized, the gas likely forms bubbles, resulting in image defects.
The methods (4) and (5), in which discoloration occurs by light irradiation, are free from the above problems. However, because a large amount of irradiation rays are needed for discoloration in these methods, photo-discoloration is likely to occur, and it takes much time for the treatment.
Under these circumstances, JP 2002-006449 A proposes a method for discoloring a coloring layer by temperature elevation at the time of reading image information by a scanner after developing a photosensitive material at a high temperature, while fully permitting the coloring layer to exhibit its functions (filtration, antihalation, anti-irradiation, etc.) at around room temperature at which the photosensitive material is usually used. It has been found as a result of intense research, however, that because the scanner should be heated in this method, sensors such as CCD, etc. used in the scanner are affected by thermal noises, resulting in inevitable deterioration in the quality of image to be read. Also, because a reading part is controlled at a high temperature, the equipment is extremely expensive.
OBJECTS OF THE INVENTION
Accordingly, an object of the present invention is to solve the problems of the above prior art technologies, thereby providing a silver halide photosensitive material capable of reading image with high quality by a scanner, which comprising a heat-responsive-discolorable coloring layer containing a heat-responsive-discolorable coloring composition that is easily discolored by a dry treatment without image defects.
Another object of the present invention is to provide a method for forming an image using the heat-responsive-discolorable coloring composition.
SUMMARY OF THE INVENTION
As a result of intensive research in view of the above object, the inventors have found that by adding a polymer having a glass transition temperature (Tg) of 60° C. to 200° C. to a discolorable coloring composition, it is possible to obtain a heat-responsive-discolorable coloring composition, which is colored at a temperature lower than its discoloration initiation temperature (T) of 60° C. to 200° C. and substantially discolored at a temperature equal to or higher than the discoloration initiation temperature (T), and which does not recover its color once discolored, even when its temperature is lowered to a temperature lower than the discoloration initiation temperature (T) again. The present invention has been completed based on this finding.
Thus, the silver halide photosensitive material of the present invention is composed of a substrate, a heat-responsive-discolorable coloring layer and a photosensitive layer coated thereon, and the heat-responsive-discolorable coloring layer is composed of a heat-responsive-discolorable coloring composition. Further, the heat-responsive-discolorable coloring composition is colored at a temperature lower than its discoloration initiation temperature (T) and substantially discolored at a temperature equal to or higher than the discoloration initiation temperature (T), and does not recover its color once discolored, even when its temperature is lowered to a temperature lower than the di
Arakawa Jun
Ishizuka Takahiro
Chea Thorl
Fuji Photo Film Co. , Ltd.
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