Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-11-06
2002-04-23
Chea, Thorl (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S607000, C430S611000, C430S613000
Reexamination Certificate
active
06376167
ABSTRACT:
FIELD OF THE INVENTION
Present invention relates to photothermographic materials and a image recording method and image forming process by the use thereof.
BACKGROUND OF THE INVENTION
In the field of graphic arts and medical diagnosis, waste liquor produced in wet-processing of image forming material results in problems and further reduction of processing effluent is strongly desired in terms of environmental protection and space saving. Accordingly, a technique for photothermographic materials is required which enables efficient exposure by means of a laser image setter or a laser imager and formation of black images exhibiting high resolution and clearness.
As such a technique is known a thermally developable photothermographic material which comprises on a support an organic silver salt, light sensitive silver halide grains, reducing agent and a binder, as described in U.S. Pat. Nos. 3,152,904 and 3,487,075, and D. H. Klosterboer “Thermally Processed Silver Systems” (Imaging Processes and Materials) Neblette, 8th Edition, edited by Sturge, V. Walworth, and A. Shepp, page 279, 1989), etc.
The photothermographic material comprises a reducible silver source (e.g., an organic silver salt), a catalytically active amount of photo-catalyst (e.g., silver halide) and a reducing agent, which are contained in the form of a dispersion in an organic binder matrix. The photothermographic material is stable at ordinary temperature and forms silver through an oxidation-reduction reaction between a reducible silver source (functioning as an oxidant) and a reducing agent when exposed and heated at a high temperature (e.g., 80° C. or higher).
The oxidation-reduction reaction is promoted by catalytic action of the latent image produced by exposure to light. Silver formed from the reaction of the organic silver salt in the exposed area provides a black image which is contrasted with the unexposed area, leading to image information. There are employed antifoggants to restrain fogging accompanied with image formation and the most effective method of conventional technologies for restraining fogging is the use of a mercury compound as an antifoggant.
Incorporation of a mercury compound as an antifoggant into a photothermographic material is described, for example, in U.S. Pat. No. 3,589,903. However, the use of highly toxic mercury compounds is not desirable and development of a non-mercury type antifoggant has been desired. Various kinds of polyhalogen compounds are described as a non-mercury type antifoggant, in U.S. Pat. Nos. 3,874,946, 4,756,000 and 5,340,712; European patent Nos. 605,981A1, 622,666A1 and 631,176A1; JP-B No. 54-165 (hereinafter, the term, JP-B refers to a published Japanese Patent) and JP-A No. 7-2781 (hereinafter, the term, JP-A refers to an examined and published Japanese Patent Application).
However, these compounds resulted in problems that an antifogging effect was relatively low or silver image tone was deteriorated. There was also a problem that when a photothermographic material was exposed and processed after being forced to age under the conditions of high temperature and high humidity, fogging in unexposed areas markedly increased.
JP-A Nos. 9-160164, 9-244178, 9-258367, 9-265150, 9-281640 and 9-319022 describe poly-halogenated compounds to improve these problems. However, when these polyhalogen compounds were applied to a photothermographic material used in the laser imager for medical use or photothetmographic materials containing a contrast-increasing agent and used for an output of the laser image setter for graphic arts use and having an oscillation wavelength of 600 to 800 nm, the above-described problems were overcome but there were still problems in aging stability such that processed photothermographic materials increased a fog density with aging.
JP-A No. 6-208193 discloses a photothermographic material in which a halogenated antifoggant and a isocyanate group-containing compound are incorporated to improve storage stability in fogging. However, this technique had still problems that aging stability of images was not sufficient and this type of an antifogging compound reacted with the elapse of time at the stage of preparing a coating solution in the manufacturing process, resulting in marked variation in sensitivity of the photothermographic material.
JP-A Nos. 64-72145 and 9-281637 disclose a photothermographic material, in which a benzoylcarboxylic acid type antifoggant is incorporated to improve storage stability in fogging. However, there is still a problem that deteriorated performance such as variation in sensitivity was caused after aging storage.
In view of the foregoing, there has been desired a photothermographic material improved in the problems described above and specifically exhibiting superior storage stability in fogging.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a photothermographic material exhibiting low fogging, high sensitivity and superior storage stability, and an image recording method and an image forming process by the use of the same.
The above object of the invention can be accomplished by the following constitution:
1. A photothermographic material comprising on a support an organic silver salt, a photosensitive silver halide, a reducing agent, a binder and a compound represented by the following formula (1):
R
1
—SO
2
—O—L
1
—COOM
1
formula (1)
where in R
1
represents a hydroxy group, a mercapto group, a halogen atom, a cyano group, a sulfo group, a nitro group, a sulfino group, a hydrazino group, a heterocyclic group, a hydrocarbon group or a group formed by the combination of these groups; M
1
represents a cation; and L
1
represents a bivalent group;
2. The photothermographic material described in 1, wherein the photothermographic material further comprises a compound represented by the following formula (2):
R
2
—COOM
2
formula (2)
wherein R
2
represents a hydroxy group, a mercapto group, a halogen atom, a cyano group, a sulfo group, a nitro group, a sulfino group, a hydrazino group, a heterocyclic group, a hydrocarbon group or a group formed by the combination of these groups; M
2
represents a cation;
3. The photothermographic material described in 1, wherein the photothermographic material further comprises a compound represented by the following formula (3):
R
3
—CO—L
2
—COOM
3
formula (3)
wherein R
3
represents a hydroxy group, a mercapto group, a halogen atom, a cyano group, a sulfo group, a nitro group, a sulfino group, a hydrazino group, a heterocyclic group, a hydrocarbon group or a group formed by the combination of these groups; M
3
represents a cation and L
2
represents a bivalent group.
4. An image recording method, wherein a photothermographic material described in any one of 1 through 3 above is exposed by using a laser exposure apparatus, in which scanning laser light is not exposed at an angle substantially vertical to the exposed surface of the photosensitive material;
5. An image recording method, wherein a photothermographic material described in any one of 1 through 3 above is exposed by using a laser exposure apparatus, in which scanning laser light is longitudinally multiple;
6. An image forming method, wherein a photothermographic material described in any one of 1 through 3 above is thermally developed in a state of containing a solvent of 1 to 1000 mg/cm
2
.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be further described in detail. In photothermographic materials according to this invention, it was found that the use of the compound represented by formula (1) and containing a sulfonyloxy group and a carboxy group and/or its salt led to markedly enhanced storage stability with respect to fogging, as compared to benzoylcarboxylic acid type antifoggant conventionally used in photothermographic materials it was further proved that the storage stability in fogging was further enhanced by the use of the compound of formula (1) in combination with the compound represented by formula (2) or (3
Bierman, Muserlian and Lucas
Chea Thorl
Konica Corporation
LandOfFree
Photothermographic material 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, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photothermographic material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2839022