Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2002-06-17
2003-10-28
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S523000, C430S531000, C430S620000, C430S631000
Reexamination Certificate
active
06638707
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to photothermographic materials and image recording method by the use thereof.
BACKGROUND OF THE INVENTION
In the field of graphic arts and medical treatment, there have been concerns in processing of photographic film with respect to effluent produced from wet-processing of image forming materials, and recently, reduction of the processing effluent is strongly demanded in terms of environmental protection and space saving. There has been desired a photothermographic dry imaging material for photographic use, capable of forming distinct black images exhibiting high sharpness, enabling efficient exposure by means of a laser imager or a laser image setter. Known as such a technique are thermally developable silver salt photographic materials (which are the same as photothermographic materials, as described in the present invention) comprising on a support an organic silver salt, light-sensitive silver halide and a reducing agent, as described in D. Morgan and B. Shely, U.S. Pat. Nos. 3,152,904 and 3,487,075, and D. H. Klosterboer, “Thermally Processed Silver Systems” in IMAGING PROCESSES and MATERIALS, Neblette's Eighth Edition, edited by J. M. Sturge, V. Walworth, and A. Shepp (1969) page 279. The thermally developable silver salt photographic material provides a simply and environment-friendly system for users, without using any processing solution.
There was proposed a photothermographic material, in which compounds, called a contrast-increasing agent or silver-saving agent were incorporated, resulting in higher densities relative to a photothermographic material not containing such compounds, in the case of silver coverage being equal. Various compounds, as a contrast-increasing agent or silver-saving agent (hereinafter, denoted as a silver-saving agent) have been proposed, as described in U.S. Pat. Nos. 5,496,695, 5,545,505, 5,545,507, 5,637,449, 5,645,130, 5,635,339, 5,545,515 and 5,686,228; JP-A Nos. 10-339929, 11-84576, 11-95365, 11-95366, 11-109546, 11-119372, 11-119373, 2000-356834, and 2001-27790 (hereinafter, the term, JP-A is referred to as an unexamined, published Japanese Patent Application).
However, problems arose with a photothermographic material with built-in silver saving agents that the density in unexposed area varied depending on aging conditions of the photothermographic before being processed and an intended density was not obtained. Furthermore, compounds described in the foregoing patents, which easily increase image contrast are advantageous for images requiring high contrast but are not always advantageous for the use requiring delicate gradation, such as clinical photography.
There were also proposed photothermographic materials containing a silane coupling agent, such as silane alkoxide compounds in the image forming layer or protective layer, as described in U.S. Pat. Nos. 4,741,992, 4,886,739, 5,264,334 and 5,294,526. However, such a silane coupling agent described therein were incorporated for the purpose of enhancing adhesion to the protective layer, not for silver-saving.
SUMMARY OF THE INVENTION
In view of the foregoing, the present invention was achieved. Thus, it is an object of the invention to provide a photothermographic material containing a novel silver-saving agent, leading to superior gradation, relatively high maximum density and low fogging density, prevention of occurrence of interference fringes and improved stability in coating solution and raw stock stability, and a suitable image recording method by the use thereof.
The object described above can be accomplished by the following constitution:
A photothermographic material comprising a support having thereon an image forming layer containing an organic silver salt, photosensitive silver halide and a reducing agent, the photothermographic material further having a protective layer on the image forming layer and optionally an interlayer between the support and the image forming layer, wherein at least one of the image forming layer and the interlayer contains an alkoxy-silane compound having at least two primary or secondary amino groups or a salt thereof, or a Schiff base formed through dehydration condensation of an alkoxy-silane compound having at least one primary amino group and a ketone compound.
1. A photothermographic material comprising a support having thereon an image forming layer comprising an organic silver salt, photosensitive silver halide and a reducing agent and further thereon a protective layer, wherein the image forming layer contains an alkoxy-silane compound having at least two primary or secondary amino groups or a salt of thereof;
2. A photothermographic material comprising a support having thereon an image forming layer comprising an organic silver salt, photosensitive silver halide and a reducing agent and further thereon a protective layer, wherein the image forming layer comprises a Schiff base, which has been formed through dehydration condensation of an alkoxy-silane compound having at least one primary amino group and a ketone compound;
3. The photothermographic material described in 2. above, wherein the Schiff base has at least one secondary amino group within the molecule:
4. The photothermographic material described in any of 1. through 3. above, wherein the image forming layer comprises an isocyanate compound having at least two isocyanate groups within the molecule;
5. A photothermographic material comprising a support having thereon an interlayer, an image forming layer comprising an organic silver salt, photosensitive silver halide and a reducing agent, and a protective layer in this order, wherein the interlayer comprises an alkoxy-silane compound having at least two primary or secondary amino groups or its salt;
6. A photothermographic material comprising a support having thereon an interlayer, an image forming layer comprising an organic silver salt, photosensitive silver halide and a reducing agent, and a protective layer in this order, wherein the interlayer comprises a Schiff base, which has been formed through dehydration condensation of an alkoxy-silane compound having at least one primary amino group and a ketone compound;
7. The photothermographic material described in 6. above, wherein the Schiff base has at least one secondary amino group within the molecule;
8. The photothermographic material described in any of 5. through 7 above, wherein the image forming layer contains an isocyanate compound having at least two isocyanate groups within the molecule;
9. The photothermographic material described in any of 1. through 8. above, wherein the image forming layer comprises an acid anhydride;
10. An image recording method, wherein when recording an image on the photothermographic material as claimed in any of 1 through 9, exposure is conducted at an angle between the surface to be exposed and a laser beam of being substantially not vertical;
11. An image recording method, wherein when recording an image on the photothermographic material as claimed in any of 1 through 9, exposure is conducted using a laser light scanning exposure machine of longitudinal multiple laser scanning light;
12. An image recording method, wherein when recording an image on the photothermographic material as claimed in any of 1 through 9, scanning exposure is conducted using at least two laser beams;
13. The image recording method as described in any of 10 through 12, the scanning exposure is conducted using a laser at a wavelength of 700 to 1200 nm.
DETAILED DESCRIPTION OF THE INVENTION
As a result of study of the inventors of this invention, it was found that incorporation an alkoxy-silane compound into image forming layer or interlayer of a photothermographic material enabled to save silver, leading to little variation in sensitivity at a relatively low fogging level, irrespective of storage conditions prior to thermal development and resulting in images with not so high contrast.
Next, photothermographic materials relating to the invention will be described. In one embodiment of the invention, th
Chea Thorl
Konica Corporation
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