Radiation imagery chemistry: process – composition – or product th – Thermographic process – Heat applied after imaging
Reexamination Certificate
1998-10-21
2001-10-23
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Thermographic process
Heat applied after imaging
C430S503000, C430S576000, C430S581000, C430S583000, C430S584000, C430S585000, C430S617000
Reexamination Certificate
active
06306566
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a heat developable light-sensitive material, a heat development image forming process, a thermal image recording material, a thermally decoloring image recording process and a process for decoloring cyanine dye.
BACKGROUND OF THE INVENTION
A heat developable light-sensitive material (or a photothermographic material) has already been proposed, and is described in U.S. Pat. Nos. 3,152,904, 3,457,075, and B. Shely “Thermally Processed Silver Systems” (Imaging Processes and Materials, Neblette eighth edition, edited by Sturge, V. Walworth and A. Shepp, page 2, 1996).
The heat developable light-sensitive material generally has a light-sensitive layer, which contains a catalytically active amount of a photo catalyst (e.g., silver halide), a reducing agent, a reducible silver salt (e.g., organic silver salt) and a color toning agent dispersed in a binder matrix. The color toning agent has a function of controlling color tone of silver. A heat development image forming process comprises steps of imagewise exposing to light the heat developable light-sensitive material, and then heating the light-sensitive material at an elevated temperature (not lower than 80° C.) to cause an oxidation-reduction reaction between the silver halide or the reducible silver salt (which functions as an oxidizing agent) and the reducing agent. Thus a black silver image is formed. The oxidation-reduction reaction is accelerated by a catalytic function of a silver halide latent image formed at the exposing step. Accordingly, the black silver image is formed within the exposed area.
The heat development does not require processing solutions of a wet development. The heat development can easily and rapidly be conducted, compared with the wet development. However, the wet development is still a major photographic technology, while the heat development is minor. The heat development has unsolved problems, while the wet development does not have the problems.
A photographic material usually contains a dye, such as a filter dye, an antihalation dye or an antiirradiation dye. The dye functions at the exposing step. If the dye remains in the photographic material after image formation, a formed image would be colored with the dye. Therefore, the dye should be removed from a photographic material at a developing step. At the wet development, the dye can easily be removed from a photographic material by using processing solutions. On the other hand, it is very difficult (substantially impossible) to remove the dye from a photographic material at the heat development.
A simple, easy and rapid development has been desired in the field of recent photography, especially in the field of recent clinical or printing photography. The improvement of the conventional wet development, however, has nearly reached its limits. Therefore, much attention has been paid again to a heat development image forming process in the field of clinical or printing photography.
Since it is very difficult to remove a dye at the heat development, it has been proposed to decolor the dye at the heat development. For example, U.S. Pat. No. 5,135,842 discloses a method of decoloring a polymethine dye of a specific structure by heating a photographic material. U.S. Pat. Nos. 5,314,795, 5,324,627 and 5,384,237 disclose a method of decoloring a polymethine dye by heating a photographic material in the presence of a carbanion forming agent (nucleophilic agent).
SUMMARY OF THE INVENTION
The known process of decoloring a dye by heat has some problems. For example, some dyes are not sufficiently decolored at heat development. Other dyes are decolored while storing a heat developable light-sensitive material because the dyes are not stable. Further, some known dyes are decolored to form decomposition products that have light absorption. Therefore, a formed image (particularly highlighted area) is colored with the decomposition products. Furthermore, some decolored dyes are colored again after the heat development (particularly in the presence of an acid). Moreover, a process of decoloring a dye with another compound such as a nucleophilic agent is influenced with a (stoichiometrical or dimensional) relation between the dye and the agent. Accordingly, the decoloring reaction between the dye and the agent is relatively slow.
An object of the present invention is to provide a heat developable light-sensitive material containing a dye that is free from the above-mentioned problems.
Another object of the invention is to provide a heat development image forming method that can form a clear image in which the dye is completely decolored.
A further object of the invention is to provide a new thermal image recording material.
A furthermore object of the invention is to provide a thermally decoloring image forming process that forms a decolored image in a simple manner.
A still further object of the invention is to provide a process of decoloring a dye that is stable at room temperature by a substantially irreversible quick reaction.
The present invention provides a heat developable light-sensitive material comprising a support, a light-sensitive layer and a non-light-sensitive layer, said light-sensitive layer containing silver halide and a reducing agent, and said non-light-sensitive layer containing a cyanine dye represented by the formula (I) or a salt thereof and a base precursor:
in which R
1
is hydrogen, an aliphatic group, an aromatic group, —NR
21
R
24
, —OR
21
or —SR
21
, each of R
21
and R
24
independently is hydrogen, an aliphatic group or an aromatic group, or R
21
and R
24
are combined to form a nitrogen-containing heterocyclic ring; R
2
is hydrogen, an aliphatic group or an aromatic group; R
3
is an aliphatic group; L
1
is a methine chain consisting of an odd number of methines; and each of Z
1
and Z
2
independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromatic ring.
The invention also provides a heat development image forming process comprising steps of:
imagewise exposing to light a heat developable light-sensitive material comprising a support, a light-sensitive layer and a non-light-sensitive layer, said light-sensitive layer containing silver halide and a reducing agent, and said non-light-sensitive layer containing a cyanine dye represented by the formula (I) or a salt thereof and a base precursor: and then heating the heat developable light-sensitive material at 80 to 200° C. to form a base from the base precursor whereby the cyanine dye is decolored and to develop the silver halide.
The invention further provides a thermal image recording material comprising a support and an image recording layer, said image recording layer containing a cyanine dye represented by the formula (I) or a salt thereof and a base precursor.
The invention furthermore provides a thermally decoloring image recording process comprising imagewise heating a thermal image recording material at 80 to 200° C., said image recording material comprising a support and an image recording layer, said image recording layer containing a cyanine dye represented by the formula (I) or a salt thereof and a base precursor to form a base from the base precursor whereby the cyanine dye is decolored.
The invention still further provides a process for decoloring a cyanine dye comprising heating a cyanine dye represented by the formula (II) or a salt thereof at 80 to 200° C. in the presence of a base:
in which X
21
is —NR
24
—, —O— or —S—; each of R
21
and R
24
independently is hydrogen, an aliphatic group or an aromatic group, or R
21
and R
24
are combined to form a nitrogen-containing heterocyclic ring; R
22
is hydrogen, an aliphatic group or an aromatic group; R
23
is an aliphatic group; L
21
is a methine chain consisting of an odd number of methines; and each of Z
21
and Z
22
independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromat
Fujiwara Itsuo
Noro Masaki
Sakurada Masami
Yabuki Yoshiharu
Baxter Janet
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Walke Amanda C.
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