Dye-fixing element for color diffusion transfer process, and...

Radiation imagery chemistry: process – composition – or product th – Transfer procedure between image and image layer – image... – Diffusion transfer process – element – or identified image...

Reexamination Certificate

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C430S213000, C430S215000, C430S220000, C430S216000, C430S236000, C430S512000, C430S931000

Reexamination Certificate

active

06689533

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method for improving light fastness of an image obtained on a dye-fixing element, in an image-forming system using a photosensitive element and a dye-fixing element. More specifically, the present invention relates to an image-forming method of generating and releasing an image-forming dye by exposure of a photosensitive silver halide to light and development thereof, and diffusing and transferring the image-forming dye from a photosensitive layer to an image-receiving layer so as to form an image, with the method being capable of forming the image improved in fastness to light. The present invention also relates to a dye-fixing element used in a method of generating and releasing an image-forming dye by exposure of a photosensitive silver halide to light and development thereof, and diffusing and transferring the image-forming dye from a photosensitive layer to an image-receiving layer, to form an image.
BACKGROUND OF THE INVENTION
As a method of generating or releasing and diffusing an image-forming dye by exposure of a photosensitive silver halide to light, and development thereof, and then transferring the image-forming dye, to form an image, there are known a method using a color diffusion transfer-type photographic material (so-called instant photography), a heat-developable color diffusion transfer system, and a method using photosensitive microcapsules.
Images obtained by these methods are generally poorer in light resistance than images obtained by conventional photography system. Therefore, various methods that obtain an image improved with light resistance have been investigated.
Many methods, such as a use of a color-fading inhibitor, a contrivance of a layer structure, and a deposition of an oxygen barrier layer, have been investigated. Among these, methods using an ultraviolet absorber as a color-fading inhibitor have been reported (JP-A-46-3335 (“JP-A ” means unexamined published Japanese patent application), JP-A-57-157245 and JP-A-61-153638).
The method is effective for improving light resistance of an image. However, to exhibit the effect sufficiently, it is necessary to cut off harmful ultraviolet rays sufficiently, and to add a large amount of an ultraviolet absorber. On the other hand, it is necessary, in principle, to add the ultraviolet absorber to a layer where a dye reacts with a mordant, or to a layer that is closer to the viewing surface than the mordant layer, and doing this unavoidably hinders the diffusion of this dye.
Thus, to attain the effect of cutting off ultraviolet rays sufficiently while an undesired effect on the diffusion of the dye is minimized, the percentage of the ultraviolet absorber in the layer in which the ultraviolet absorber is added inevitably becomes high, to produce an adverse effect that the physical strength of the layer becomes weak.
Particularly in a heat-developable color diffusion transfer process using heat to form an image, a mobile material, such as a salt, an oil, a base or a precursor thereof, added to a photosensitive material or a dye-fixing element, tends to diffuse by heating, so as to weaken the physical strength of the film. Therefore, the adverse effect on the physical strength by the addition of an ultraviolet absorber is rather remarkable.
SUMMARY OF THE INVENTION
The present invention is a dye-fixing element for color diffusion transfer process, having an ultraviolet-absorbing layer that contains an ultraviolet absorber in a coating amount of 0.2 g/m
2
or more, over a mordant layer; and containing, as at least one dispersion medium for the ultraviolet absorber, a compound represented by formula (1), in a ratio (mass ratio) of 25 to 200% of the ultraviolet absorber; with the sum of coating amounts of the ultraviolet absorber and total dispersion medium contained for the ultraviolet absorber being 1.0 g/m
2
or less;
wherein x and y each represent a molar fraction of each recurring unit, the total of x and y is 1, and y ranges from 0.85 to 0.95.
Further, the present invention is an image-forming method using the above dye-fixing element.
Other and further features and advantages of the invention will appear more fully from the following description.
DETAILED DESCRIPTION OF THE INVENTION
The inventor, having made investigations to solve the above-mentioned problems, has found out that, by using a certain water-insoluble copolymer as at least one species of a dispersion medium for an ultraviolet absorber, dispersing the absorber, and introducing the absorber into a dye-fixing element, the light fastness of an image can be remarkably improved without deteriorating the physical strength of the film containing the absorber. Thus, the present invention has been made based on this finding.
According to the present invention, there are provided the following means:
(1) A dye-fixing element for a color diffusion transfer process, having an ultraviolet-absorbing layer that contains an ultraviolet absorber in a coating amount of 0.2 g/m
2
or more, over a mordant layer (on the side where an image is to be observed); and containing, as at least one dispersion medium for the ultraviolet absorber, a compound represented by formula (1), in a ratio (mass ratio) of 25 to 200% of the ultraviolet absorber, and the sum of coating amounts of the ultraviolet absorber and total dispersion medium contained for the ultraviolet absorber being 1.0 g/m
2
or less;
wherein x and y each represent a molar fraction of each recurring unit, the total of x and y is 1, and y ranges from 0.85 to 0.95.
In the present specification, the above-mentioned formula represents the molar fractions of the recurring units in the copolymer, and the bonding manner therein is not particularly limited (for example, the copolymer can be a block copolymer or a random copolymer).
(2) The dye-fixing element according to item (1), wherein, in the ultraviolet-absorbing layer, a water-soluble polymer is used as a binder, in an amount of 50 to 200% of the sum of masses of the ultraviolet absorber and total dispersion medium.
(3) The dye-fixing element according to item (2), wherein 50 to 100% of the water-soluble polymer used as the binder in the ultraviolet-absorbing layer is a gelatin.
(4) The dye-fixing element according to item (1), (2), or (3), which is used in a heat-developable color diffusion transfer process.
(5) An image-forming method, comprising using the dye-fixing element according to any one of items (1) to (4) in combination with a photosensitive element.
The present invention will be described in detail hereinafter.
The “ultraviolet-absorbing layer” in the present invention means a layer that absorbs at least one part of ultraviolet rays, which are originally to reach the next layer, by absorbing ultraviolet rays arriving at the layer. One of the distinguishing features of the ultraviolet-absorbing layer in the present invention is that an ultraviolet absorber is at least added thereto, in a coating amount of 0.2 g/m
2
or more. The upper limit of the total coating amount of the ultraviolet absorber and one or more dispersion medium(s) used to disperse the ultraviolet absorber, which will be described later, is 1.0 g/m
2
.
In the present invention, the ultraviolet-absorbing layer is arranged between protective layers, or between a protective layer and a dye-fixing layer. The ultraviolet-absorbing layer may be formed as a single layer structure, or as a multilayered structure, which has plural divided layers.
As the ultraviolet absorber to be added to the ultraviolet-absorbing layer in the present invention, a compound having an appropriate absorption property may be selected from known organic compounds, and used. A compound which is not generally used as an ultraviolet absorber, but has an absorption within the ultraviolet range from 320 nm to 400 nm—an absorption in the range has a very intense effect on light resistance of the dye-fixing element—may also be used as the ultraviolet absorber in the present invention.
In view of the advantageous effect of the present invention, the mater

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