Photothermographic material and image forming method

Details Photothermographic material and image forming method Photothermographic material and image forming method

2001-02-13

2002-11-05

Chea, Thorl (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S607000, C430S611000, C430S613000, C430S614000, C430S626000, C430S629000

Reexamination Certificate

active

06475715

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to photothermographic materials forming images through thermal processing and an image forming method by the use thereof and in particular to a technique to improve fogging levels in image formation.
BACKGROUND OF THE INVENTION
In the field of medical treatment and graphic arts, there have been problems in working property with respect to effluents produced from wet-processing of image forming materials, and recently, reduction of the processing effluent is strongly demanded in terms of environment protection and space saving. Accordingly, there are needed techniques regarding photothermographic materials for photographic use and which are capable of forming black images exhibiting high sharpness, enabling efficient exposure by means of a laser imager or laser image setter. As such a technique is known a thermally developable photosensitive material, which comprises a support having thereon an organic silver salt, light-sensitive silver halide grains and a reducing agent, as described in U.S. Pat. Nos. 3,152,904 and 3,487,075; and D. Morgan “Dry Silver Photographic Material” (Handbook of Imaging Materials, Marcel Dekker, Inc., page 48, 1991). These photosensitive materials are developed at a temperature of not less than 80° C. and called a photothermographic material.
Such a photothermographic material usually comprises a reducible silver source (e.g., organic silver salt), a catalytically active amount of photocatalyst (e.g., silver halide) and a reducing agent which are dispersed in an organic 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.
One disadvantage of the photothermographic materials is that silver is undesirably formed in the white background of unexposed areas, resulting in fog. There have been proposed various techniques to restrain such fogging, as disclosed in U.S. Pat. Nos. 3,874,946, 4,459,350, 5,340,712, 4,756,999, 5,594,143; JP-A Nos. 58-59439, 59-46641 and 59-57233 (hereinafter, the term, JP-A refers to a unexamined, published Japanese Patent Application). JP-A No. 6-208193 discloses a photothermographic emulsion containing an isocyanate group-including compound in combination with a halogenated anti-foggant, as a means for improving storage stability with respect to fogging.
However, such a technique was not sufficient in an anti-fogging effect, or even if an anti-fogging effect was sufficient, there were problems such that reduction in sensitivity was caused. There was also a problem that an increased fogging or variation in sensitivity occur during storage of the photothermographic material. Further, there were problems that when a processed photothermographic material was exposed to room light or viewing box light, an increase of fogging (so-called printing-out), variation in printing-out density during exposure and deterioration in image color due to printing-out occurred and storage stability of images was insufficient levels. Furthermore, when developer at a higher temperature to accelerate development, fogging was disadvantageously increased. There is desired development of an antifoggant without such problems.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a photothermographic material exhibiting enhanced sensitivity without causing increased fogging, lowered fogging, reduced variation in sensitivity or minimized deterioration in image color during storage, superior image stability, and improvements in disadvantageous fogging caused by development at a higher temperature.
The object of the invention can be accomplished by the following constitution:
(1) a photothermographic material comprising on a support a) an organic silver salt, b) light-sensitive silver halide, c) a reducing agent and d) a compound represented by formula (1), 6-aryl-2,4-bis(tribromomethyl)-s-triazine or a 6-heteroaryl-2,4-bis(tribromomethyl)-s-triazine:
wherein X
1
, X
2
and X
3
each represent a hydrogen atom or a substituent group, provided that at least one of X
1
, X
2
and X
3
is a halogen atom; L represents a sulfonyl group, a carbonyl group or a sulfinyl group; when L is a carbonyl group or sulfinyl group, n is 1, 2 or 3 and when L is a sulfonyl group, n is 0, 1, 2 or 3; when L is a carbonyl group or a sulfinyl group or when n is 2 or 3 and L is a sulfonyl group, Y represents a single bond, —N(R
1
)—, an oxygen atom, a sulfur atom, a selenium atom, or —(R
2
)C═C(R
3
)—, and when n is 0 or 1 and L is a sulfonyl group, Y represents —N(R
1
)—, an oxygen atom, a sulfur atom, a selenium atom, or —(R
2
)C═C(R
3
)—, in which R
1
, R
2
and R
3
each represent a hydrogen atom or a substituent group; R represents a hydrogen atom, a halogen atom or a substituted or unsubstituted aliphatic group, provided that R
1
and R, or R
3
and R may combine with each other to form an alicyclic ring.
DETAILED DESCRIPTION OF THE INVENTION
The compound represented by formula (1) will be described:
wherein X
1
, X
2
and X
3
each represent a hydrogen atom or a substituent group, provided that at least one of X
1
, X
2
and X
3
is a halogen atom; L represents a sulfonyl group, a carbonyl group or a sulfinyl group; when L is a carbonyl group or sulfinyl group, n is 1, 2 or 3 and when L is a sulfonyl group, n is 0, 1, 2 or 3; when L is a carbonyl group or a sulfinyl group or when n is 2 or 3 and L is a sulfonyl group, Y represents a single bond, —N(R
1
)—, an oxygen atom, a sulfur atom, a selenium atom, or —(R
2
)C═C(R
3
)—, and when n is 0 or 1 and L is a sulfonyl group, Y represents —N(R
1
)—, an oxygen atom, a sulfur atom, a selenium atom, or —(R
2
)C═C(R
3
)—, in which R
1
, R
2
and R
3
each represent a hydrogen atom or a substituent group; R represents a hydrogen atom, a halogen atom or a substituted or unsubstituted aliphatic group, provided that R
1
and R, or R
3
and R may combine with each other to form an alicyclic ring.
In formula (1), X
1
, X
2
and X
3
each represent a hydrogen atom or a substituent group, provided that at least one of X
1
, X
2
and X
3
is a halogen atom. The halogen atom is F, Cl, Br or I, and in cases of two or more halogen atoms, the halogen atoms may be the same or different. The halogen atom is preferably Cl or Br, and more preferably Br.
Substituent groups other than a halogen atom may be any one, including an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an acyl group, an alkoxycarbonyl group, an aryloxy group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, an acyoxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a ureido group, a phosphoric acid amido group, a sulfinyl group, hydroxy, and a heterocyclic group. Of these groups, electron-withdrawing group, i.e., a trihalomethyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group or a sulfamoyl group is preferred. It is more preferred that all of X
1
, X
2
and X
3
are halogen atoms, and it is still more preferred that X
1
, X
2
and X
3
are or Br.
R is a hydrogen atom, a halogen atom or a substituted or unsubstituted aliphatic group, and preferably an alkyl group.
R
1
, R
2
and R
3
are each a hydrogen atom or a substituent group, and preferably —N(R
1
)—, an oxygen atom or a vinyl group and when Y is —N(R
1
)—, R
1
is preferably an alkyl group.
Alternatively, the compound of formula (1) may be represented by formula (1
a
), (1
b
) or (1
c
):
wherein X
1
, X
2
and X
3
each represent a hydrogen ato

Affiliated with

Also associated with

Rating

Photothermographic material and image forming method 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 image forming method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photothermographic material and image forming method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2985239