Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2002-04-18
2003-10-28
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S264000, C430S599000, C430S620000
Reexamination Certificate
active
06638706
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a photothermographic recording material and in more detail to a photothermographic recording material which exhibits improved distinguishability between the front and the back surface.
BACKGROUND OF THE INVENTION
Heretofore, in the graphic arts and medical fields, effluent resulting from wet processing for image forming materials has caused problems with workability. In recent years, from the viewpoint of environmental protection as well as space saving, a decrease in said processing effluent has been increasingly demanded. As a result, techniques have been needed, which relate to photothermographic materials which can be efficiently exposed employing laser image setters and laser imagers, and can form clear black-and-white images exhibiting high resolution.
Said techniques are described in, for example, U.S. Pat. Nos. 3,152,904 and 3,487,075, as well as Morgan et al., “Dry Silver Photographic Materials” in Handbook of Imaging Materials, published by Marcel Dekker Inc., page 48, 1991. Further, photothermographic recording materials (hereinafter simply referred to as recording materials) are known, which comprise a support having thereon organic silver salts, light-sensitive silver halide grains, reducing agents, and binders.
Said photothermographic recording materials form photographic images utilizing heat development and comprise reducible silver sources (being organic silver salts), light-sensitive silver halides, reducing agents, and if desired, image color control agents which control the color of silver images, which are commonly dispersed into an (organic) binder matrix. Said photothermographic recording materials are stable at room temperature. However, when, after image exposure, they are heated to a relatively high temperature (for example, 80 to 140° C.), images are formed by development. When heated, silver is formed through an oxidation-reduction reaction between said organic silver salts (which work as oxidizing agents) and said reducing agents. The rate of said oxidation-reduction reaction is enhanced by the catalytic action of a latent image which has been formed by exposed silver halides. Silver, which is formed through the reaction of organic silver salts in the exposed area, provides a blackened image portion, while the unexposed area remains as it is, whereby an image is formed. Said reaction proceeds without supply of any processing solutions such as water.
When these photothermographic recording materials are employed as graphic arts materials, after heat development, a press plate is commonly exposed through the resultant material and is employed for printing. When said exposure to the press plate is carried out, the front and the back of said photothermographic material are distinguished. However, when distinguishability between the front and the back surface is difficult, namely the front and the back surface exhibiting no visual difference, sufficient care is required for ascertaining that. As a result, a decease in work efficiency results.
SUMMARY OF THE INVENTION
From the viewpoint of the foregoing, the present invention was achieved. It is an object of the present invention to provide a photothermographic recording material which exhibits excellent distinguishability between the front and the back surface and increases efficiency of press-plate making work.
The object of the present invention has been achieved employing the following embodiments.
(1) A photothermographic recording material comprising on one side of a support an image recording layer comprising a light-insensitive organic silver salt, a photosensitive silver halide, a reducing agent for silver ions and a binder, wherein the difference in specular glossiness at an angle of 60° between a thermally developed exposed area of the image recording layer and the bottom support surface opposite the thermally developed exposed area is at least 15.
(2) The photothermographic recording material of item (1), wherein the specular glossiness of the thermally developed exposed area of the image recording layer is smaller than the specular glossiness of the bottom support surface opposite the thermally developed exposed area.
(3) The photothermographic recording material of item (1), wherein the image recording layer further comprises a high contrast agent represented by Formula (1),
wherein each R
1
and R
2
is independently a substituent group and at least one of R
1
and R
2
represents a cyano group; and M represents H or an alkali metal atom.
(4) The photothermographic recording material of item (1), wherein the image recording layer further comprises a high contrast agent represented by Formula (2),
wherein L
1
represents a divalent organic group which is capable of forming a ring; and M represents H or an alkali metal atom.
(5) The photothermographic recording material of item (1), wherein the recording material further comprises an adjacent layer in direct contact with the image recording layer, and at least one of the image recording layer and the adjacent layer comprises a high contrast agent represented by Formula (1),
wherein each R
1
and R
2
is independently a substituent group and at least one of R
1
and R
2
represents a cyano group; and M represents H or an alkali metal atom.
(6) The photothermographic recording material of item (1), wherein the recording material further comprises an adjacent layer in direct contact with the image recording layer, and at least one of the image recording layer and the second layer comprises a high contrast agent represented by Formula (2),
wherein L
1
represents a divalent organic group which is capable of forming a ring; and M represents H or an alkali metal atom.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be detailed.
The invention according to item (1) is characterized in that specular glossiness difference (in terms of an absolute value) between the surface of a blackened area after development on the side which is coated with an image recording layer and the surface on the side which is not coated with said image recording layer is at least 15 at a measured angle of 60 degrees. Further, the invention according to item (2) is characterized in that glossiness difference between the surface of a blackened area after development on the side (hereinafter occasionally referred to as an image recording layer side), which is coated with an image recording layer, and the surface on the side, which is not coated with said image recording layer, is at least 15 at a measured angle of 60 degrees, and in addition, glossiness of the surface on the side (hereinafter occasionally referred to as a backing layer side) which is not coated with said image recording layer is greater than that of the surface on the side coated with said image recording layer.
The specular glossiness at a measured angle of 60 degrees, as described in the present invention, refers to the value determined in accordance with JIS Z8741, and is expressed by glossiness with respect to a glass surface at an incident angle of 60 degrees. ISO 2813:1994 is a International Standard which corresponds to JIS Z8741. The title of ISO 2813 is “Paints and varnishes−Determination of specular gloss of non-metallic paint films at 20°, 60° and 85°”. Even though the glossiness of the image recording layer side in the present invention is not definitely determined due to the fact that relative glossiness with the backing layer side is taken into account, said glossiness is preferably from 40 to 70, is more preferably from 45 to 65, and is most preferably from 50 to 60. Further, even though glossiness of the backing layer side is also not definitely determined due to the fact that the relative glossiness with the image recording layer side is taken into account, said glossiness is preferably from 55 to 100, is more preferably from 70 to 95, and is most preferably from 80 to 95. It is characterized that the absolute value of glossiness difference between the image recording layer side and the backing layer side i
Chea Thorl
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
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