Radiation imagery chemistry: process – composition – or product th – Thermographic process – Heat applied after imaging
Reexamination Certificate
2001-07-11
2003-04-15
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Thermographic process
Heat applied after imaging
C430S523000, C430S531000, C430S619000, C430S950000
Reexamination Certificate
active
06548232
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to photothermographic materials and a processing method thereof.
BACKGROUND OF THE INVENTION
There are known a number of photosensitive materials comprising a support having thereon a photosensitive layer, which forms images upon imagewise exposure. Of these, techniques of forming images through thermal development are cited as a system suitable for environmental protection and simplifying image forming means. There are known thermally developable photothermographic materials comprising on a support having thereon an organic silver salt, silver halide grains, a reducing agent and a binder, as described, for example, in D. Morgan and B. Shely, U.S. Pat. Nos. 3,152,904 and 3,457,075, and D. Morgan, “Dry Silver Photographic Materials” (Handbook of Imaging Materials, Marcel Dekker, Inc. page 48, 1991), etc.
Such a photothermographic material contains a reducible light-insensitive silver source (such as organic silver salts), a catalytically active amount of photocatalyst (such as silver halide) and a reducing agent, which are dispersed in a binder matrix. The photothermographic materials are stable at ordinary temperature and forms silver upon heating, after exposure, at a relatively high temperature (e.g., 80° C. or higher) through an oxidation-reduction reaction between the reducible silver source (which functions as an oxidizing agent) and the reducing agent. The oxidation reduction reaction is accelerated by catalytic action of a latent image produced by exposure. Silver formed through reaction of the reducible silver salt in exposed areas provides a black image, which contrasts with non-exposes areas, leading to image formation. Such photothermographic materials meet requirements for simplified processing and environmental protection.
Such photothermographic materials have been mainly employed as photographic materials mainly for use in micrography and medical radiography, but partly for use in graphic arts. This is due to the fact that the maximum density (also denoted as Dmax) of obtained images is still low and the contrast is relatively low so that desired quality levels for graphic arts have not yet been achieved.
Along with advances in laser and light-emitting diodes, on the other hand, development of a recording material suitable for scanners having oscillating wavelengths at 700 to 800 nm and exhibiting enhanced sensitivity, relatively high density and high contrast is strongly desired.
U.S. Pat. No. 3,667,958 disclosed a photothermographic recording material employing the combination of polyhydroxybenzenes and hydroxyamines, reductones or hydrazines exhibits enhanced image quality discrimination and resolving power, but it was proved that such a combined use of reducing agents often caused increased fogging. U.S. Pat. Nos. 5,464,738 and 5,496,695 disclosed photothermographic materials containing an organic silver salt, silver halide, hindered phenols and hydrazine derivatives. However, the use of such hydrazine derivatives resulted in problems such that sufficiently high Dmax or contrast could not be obtained and black spots often resulted, deteriorating image quality. Hydrazine derivatives, improved in black spots were disclosed in JP-A Nos. 9-292671, 9-304870, 9-304871, 9-304872 and 10-31282 (hereinafter, the term, JP-A refers to unexamined, published Japanese Patent Application). Further, JP-A No. 10-62898 disclosed hydrazine derivatives resulting in improved image reproducibility but there were problems that a satisfactory level was not still achieved with respect to all of the maximum density, ultra-high contrast, improved black spots, dot reproducibility and dimensional stability. There were also such problems that the disclosed hydrazine derivatives led to inferior results in storage stability (such as increased fogging).
Recently, the desire for rapid access has becomes stronger. Specifically, in cases when a photothermographic material exhibiting relatively high maximum density and high contrast is subjected to rapid processing, problems are arose that roller marks or unevenness in density often occurs, leading to deteriorated image quality and it is desired to overcome such problems.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a photothermographic material causing no roller mark nor unevenness in density and exhibiting relatively high maximum density and high contrast, even when subjected to rapid processing, and a processing method by the use thereof.
The above object of the invention is achieved by the following constitution:
1. A photothermographic material comprising a support having thereon an image recording layer comprising an organic silver salt, a silver halide, a reducing agent and a binder, wherein the outermost surface of the image recording layer side of the photothermographic material exhibits a difference in center-line mean roughness (Ra) of not more than 10 nm between before and after being subjected to thermal processing;
2. the photothermographic material described in 1., wherein an absolute value of a thermal dimensional variation rate between before and after being subjected to the thermal processing is 0.001 to 0.04% in both the longitudinal direction and the traverse direction;
3. the photothermographic material described in 1., wherein a protective layer is provided on the image recording layer side and farther from the support than the image recording layer;
4. the photothermographic material described in 3., wherein the protective layer comprises a binder exhibiting a glass transition point of 75 to 200° C., and the binder of the image recoding layer exhibiting a glass transition point of 45 to 150° C.;
5. the photothermographic material described in 1., wherein the outermost surface of the image recording layer side of the photothermographic material exhibits an ultra-micro hardness of 1.1 to 4.0 GPa;
6. the photothermographic material described in 1., wherein the image recording layer further comprises a filler;
7. the photothermographic material described in 3., wherein the protective layer comprises a filler;
8. the photothermographic material described in 1., wherein at least 50% by weight of the binder contained in the image recording layer is accounted for by a polymeric latex;
9. the photothermographic material described in 8., wherein the image recording layer is formed by using a coating solution of the image recording layer, the coating solution containing water in an amount of at least 30% by weight, based on a solvent contained in the coating solution;
10. a processing method of a photothermographic material comprising:
subjecting a photothermographic material comprising a support having thereon an image recording layer comprising an organic silver salt, a silver halide, a reducing agent and a binder to thermal processing by use of a thermal processing machine, wherein the outermost surface of the image recording layer side of the photothermographic material exhibits a difference in center-line mean roughness (Ra) of not more than 10 nm between before and after being subjected to thermal processing;
11. the processing method described in 10., wherein the processing machine transports the photothermographic material at a rate of 22 to 40 mm/sec;
12. a photothermographic material comprising a support having thereon an image recording layer comprising an organic silver salt, a silver halide, a reducing agent and a binder, wherein a variation of center-line mean roughness (Ra) on the outermost surface of the image recording layer side of the photothermographic material is not more than 10 nm between before and after being subjected to thermal processing;
13. a method of processing a photothermographic material comprising a support having thereon an image recording layer containing an organic silver salt, a silver halide, a reducing agent and a binder by use of a thermal processing machine, wherein a variation of center-line mean roughness (Ra) on the outermost surface of the image recording layer side of the photothermograph
Chea Thorl
Konica Corporation
Muserlian Lucas and Mercanti
LandOfFree
Photothermographic material and processing method thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photothermographic material and processing method thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photothermographic material and processing method thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3050872