Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
1999-09-30
2001-01-16
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S610000, C430S613000
Reexamination Certificate
active
06174663
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a so-called heat-developable image-recording material, in which an image is developed by heating without using a developer solution.
BACKGROUND OF THE INVENTION
Heat-developable image-recording materials that can produce images by using the heat development process have been known, and disclosed in, for example, U.S. Pat. Nos. 3,152,904, 3,457,075, and “Imaging Processes and Materials”, Neblette's 8th edition, pp.279-291 (1969). The image-recording materials disclosed in the aforementioned literature comprise a silver source which can be reduced (for example, organic silver salt), a catalytically active amount of photocatalyst (for example, silver halide), a color-tone adjustor for controlling tonality of silver, and a reducing agent, which are dispersed in a binder. Such heat-developable image-recording materials are stable at an ambient temperature, but they form blackened silver through oxidation-reduction reaction of the reducible silver salt and the reducing agent when they are heated to an elevated temperature (e.g., 120° C.) after light exposure. This reaction is promoted by catalytic action of latent image generated by the light exposure.
As another image-forming scheme, when the materials do not contain the catalytic amount of silver halide, blackened images can also be obtained by imagewise tracing at an elevated temperature on the materials with a thermal head.
Such image-formation methods require no processing solution such as a developer, and provide images only by heating. The methods do not generate sulfite gas, ammonia gas and the like, and therefore, the materials have been focused as recording materials used in image-forming apparatuses utilizing laser rays. Laser image-forming apparatuses have been used in various fields such as image-forming apparatuses for medical use, photomechanical reproduction, and other industrial use.
These heat-developable recording materials generally require heating at a temperature of 110° C. or higher for 10 seconds to 60 seconds. Output speeds have become faster with the progress of laser image-forming apparatuses, and it has been desired to improve sensitivity and developing speed of the recording materials. In recent years, especially as heat-developable recording materials for photomechanical reproduction, materials utilizing infectious development with an ultrahigh contrast agent have been developed. However, since the infectious development requires prolonged heating time, it has been desired to realize more faster developing speed. Since fog is generally enhanced when the development temperature is elevated to obtain a faster developing speed, an increase of the developing temperature is limited. Therefore, there has been desired a heat-developable recording material that can be developed at a high developing speed within a temperature range that does not enhance the fog.
As conventional high contrast agents for producing high contrast images, there have been disclosed, for example, acylhydrazine derivatives (U.S. Pat. Nos. 5,464,738, 5,512,411, 5,496,695, and 5,536,622), acrylonitrile derivatives (U.S. Pat. Nos. 5,545,516 and 5,635,339), malondialdehydes (U.S. Pat. No. 5,654,130), isoxazoles (U.S. Pat. No. 5,705,324) and the like. As method for accelerating development processes, uses of amine compounds (U.S. Pat. No. 5,545,505), hydroxamic acids (U.S. Pat. No. 5,545,507), hydrogen donors (U.S. Pat. No. 5,637,449) and the like are disclosed.
However, they are still insufficient to achieve a desired high developing speed, and a further effective means has been desired.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an improved heat-developable image-recording material. More specifically, the object of the present invention is to provide a heat-developable image-recording material that enables rapid development.
The aforementioned object was achieved by the present invention, and the present invention thus provides a heat-developable image-recording material comprising an organic silver salt, a reducing agent, and an organic binder, wherein the material further comprises a compound represented by the following formula (I) or (II):
wherein, R
1
is a group selected from hydrogen atom, an alkyl group, an aryl group, hydroxyl group, amino group, thiol group, an alkoxyl group, and thioether group.
R
2
and R
3
may be the same or different and represent hydrogen atom or 1 to 4 functional groups.
According to a preferred embodiment of the aforementioned heat-developable image-recording material of the present invention, the material further contains a photosensitive silver halide grains.
According to another preferred embodiment of the aforementioned heat-developable image-recording material of the present invention, the material further contains a high contrast agent.
PREFERRED EMBODIMENT OF THE INVENTION
The heat-developable image-recording material of the present invention contains an organic silver salt, a reducing agent, and an organic binder, and is characterized to further contain a compound represented by the following formula (I) or (II).
In the formulas, R
1
is a group selected from hydrogen atom, an alkyl group, an aryl group, hydroxyl group, amino group, thiol group, an alkoxyl group, and thioether group.
R
2
and R
3
may be the same or different and represent hydrogen atom or 1 to 4 functional groups.
The alkyl group represented by R
1
is preferably an unsubstituted or substituted alkyl group having 1 to 30 carbon atoms. The substituent of the alkyl group may preferably be selected from hydroxyl group, an aryl group which may be substituted, an amino group which may be substituted, carbonyl group, carbamoyl group, thiol group, an alkoxyl group, thioether group and a group composed of a repeating unit of ethyleneoxy or propyleneoxy group. The aryl group which may be substituted is preferably a phenyl group substituted with 1 to 3 hydroxyl groups or amino groups.
Particularly preferred examples of the alkyl group represented by R
1
include an alkyl group substituted with one or more hydroxyl groups, an alkyl group substituted with one or more phenyl groups having 1 to 3 hydroxyl groups or amino groups, and an alkyl group having a repeating unit of ethyleneoxy or propyleneoxy group.
The aryl group represented by R
1
is preferably an unsubstituted or substituted phenyl group or naphthyl group. The substituent of the aryl group may preferably be selected from hydroxyl group, an amino group which may be substituted, an alkyl group having 1 to 30 carbon atoms, carbonyl group, carbamoyl group, thiol group, an alkoxyl group, thioether group, and a group composed of a repeating unit of ethyleneoxy or propyleneoxy group. Preferred example of the aryl group represented by R
1
include a phenyl group substituted with one or more hydroxyl groups or amino groups.
Particularly preferred examples of R
1
include hydrogen atom, an alkyl group substituted with one or more hydroxyl groups, and a phenyl group substituted with one or more hydroxyl groups.
R
2
and R
3
each represent hydrogen atom or a functional group that is substitutable at any position of the benzene ring. The functional group may be selected from various functional groups. Preferably, the functional group may be selected from hydroxyl group, an amino group which may be substituted, an alkyl group having 1 to 30 carbon atoms, carbonyl group, carbamoyl group, thiol group, an alkoxyl group, thioether group, and a group composed of a repeating unit of ethyleneoxy or propyleneoxy group, carboxyl group, cyano group, and phenyl group. Preferably, R
2
and R
3
are independently hydrogen atom or an alkyl group having 1 to 30 carbon atoms.
These compounds may be added to an image-forming layer containing an organic silver salt or other layers (a protective layer, an intermediate layer, an anti-halation layer, an undercoat layer and the like).
These compounds are dissolved in water or an organic solvent such as methanol, ethanol, acetone, DMF, and ethyl acetate before the additio
Birch & Stewart Kolasch & Birch, LLP
Chea Thorl
Fuji Photo Film Co. , Ltd.
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