Blocked leuco dyes for photothermographic elements
AssigneeMinnesota Mining and Manufacturing Company
InventorsLarry R. Krepski, Sharon M. Simpson, Kim M. Vogel
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Abstract
A photothermographic element containing a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer is provided. The emulsion layer comprises: (a) a photosensitive silver halide; (b) a non-photosensitive, reducible source of silver; (c) a leuco dye reducing agent; and (d) a binder; wherein the leuco dye reducing agent comprises a blocked leuco dye compound of the general formula L-R.sup.1, which is capable of being oxidized to a colored form, wherein: (i) L is a group remaining after removal of a hydrogen from a leuco dye; and (ii) R.sup.1 is a C(O)--NH--SO.sub.2 --R.sup.5 group wherein R.sup.5 is an aliphatic group or an aromatic group.
Claims18
A photothermographic element comprising a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer comprising:
- (a) a photosensitive silver halide;
- (b) a non-photosensitive, reducible source of silver;
- (c) a leuco dye reducing agent;
- and
- (d) a binder;
- wherein the leuco dye reducing agent comprises a chromogenic leuco dye compound of the general formula:
- ##STR31## wherein:
- (a) R is hydrogen or halogen;
- (b) R.sup.1 is a C(O)--NH--SO.sub.2 --R.sup.5 group, wherein R.sup.5 is an aliphatic group containing 1-50 carbon atoms or an aromatic group containing 5-50 carbon atoms;
- (c) R.sup.2 is a hydrogen atom, an alkoxy group, or an alkyl group;
- (d) R.sup.3 and R.sup.4 are each independently an aliphatic group, an aromatic group, or an -X-Y group, wherein X is an alkylene group containing 1-4 carbon atoms, and Y is a cyano group, a halogen atom, an alkoxy group containing 1-20 carbon atoms, or --OH;
- and
- (e) Cp is a coupler group.
A photothermographic element comprising a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer comprising:
- (a) a photosensitive silver halide;
- (b) a non-photosensitive, reducible source of silver;
- (c) a leuco dye reducing agent;
- and
- (d) a binder;
- wherein the leuco dye reducing agent comprises a chromogenic leuco dye compound of the general formula:
- ##STR32## wherein:
- (a) R is hydrogen or halogen;
- (b) R.sup.1 is a C(O)--NH--SO.sub.2 --R.sup.5 group, wherein R.sup.5 is a ballasting group;
- (c) R.sup.2 is a hydrogen atom, an alkoxy group, or an alkyl group;
- (d) R.sup.3 and R.sup.4 are each independently an aliphatic group, an aromatic group, or an -X-Y group, wherein X is an alkylene group containing 1-4 carbon atoms, and Y is a cyano group, a halogen atom, an alkoxy group containing 1-20 carbon atoms, or --OH;
- and
- (e) Cp is a coupler group.
A method of producing an image comprising:
- (a) imagewise exposing an element comprising a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer comprising:
- (i) a photosensitive silver halide;
- (ii) a non-photosensitive, reducible source of silver;
- (iii) a leuco dye reducing agent;
- and
- (iv) a binder;
- wherein the leuco dye reducing agent comprises a chromogenic leuco dye compound of the general formula:
- ##STR33## wherein:
- (A) R is hydrogen or halogen;
- (B) R.sup.1 is a C(O)--NH--SO.sub.2 --R.sup.5 group, wherein R.sup.5 is an aliphatic group containing 1-50 carbon atoms, an aromatic group containing 5-50 carbon atoms, or a ballasting group;
- (C) R.sup.2 is a hydrogen atom, an alkoxy group, or an alkyl group;
- (D) R.sup.3 and R.sup.4 are each independently an aliphatic group, an aromatic group, or an -X-Y group, wherein X is an alkylene group containing 1-4 carbon atoms, and Y is a cyano group, a halogen atom, an alkoxy group containing 1-20 carbon atoms, or --OH;
- and
- (E) Cp is a coupler group;
- and
- (b) heating the element to a sufficient temperature for a sufficient time to develop the image.
Dependencies are inferred from the claim text.