# US 5,705,311 A · Heat-developable image-recording element

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- Number: US 5,705,311 A
- Document ID: US5705311A
- Status: Granted
- Kind: A
- Application number: 08/607,288
- Filed: 1996-02-26
- Granted: 1998-01-06
- Earliest claimed: 1996-02-26
- Assignees: Polaroid Corporation
- Inventors: Kent M. Young
- Web page: https://patentgrep.com/patent/US5705311A

## CPC

- G03C 8/4013: {using photothermographic silver salt systems, e.g. dry silver (G03C1/4989 takes precedence)}
- G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G)

## Abstract

A heat developable photosensitive image-recording element is described comprising photosensitive silver halide, either as the only source of silver present or in association with a substantially light-insensitive source of silver, a reducing agent, a silver solvent and an image-receiving layer including silver nucleating material. The total amount of silver present is arranged in two adjacent discrete layers, one of which includes the silver reducing agent and the other of which does not. The image-recording element provides an image having significantly increased image density upon exposure and photographic processing.

## Claims

### Claim 1

A heat-developable image-recording element comprising
a first support and an optional second support and carried by said first support or confined between said first and second supports
a silver solvent,
a silver reducing agent,
an image-receiving layer comprising silver nucleating material,
a first layer including photosensitive silver halide adjacent to a second layer including photosensitive silver halide,
wherein said first layer includes said silver reducing agent and said second layer does not include any silver reducing agent and said first layer is closer to said image-receiving layer than said second layer.

### Claim 2 (depends on 1)

The image-recording element as defined in claim 1 wherein said photosensitive silver halide of said first layer is the same as said photosensitive silver halide of said second layer.

### Claim 3 (depends on 2)

The image-recording element as defined in claim 2 wherein about two-thirds of the combined amount of photosensitive silver halide in said first and second layers is present in said first layer and about one-third is present in said second layer.

### Claim 4 (depends on 1)

The image-recording element as defined in claim 1 and further including means for providing alkali.

### Claim 5 (depends on 4)

The image-recording element is defined in claim 4 wherein said means for providing alkali includes two reactants which are capable of reacting to form an alkali.

### Claim 6 (depends on 1)

The image-recording element as defined in claim 1 which includes said second support and said image-receiving layer is carried by said second support.

### Claim 7

A heat-developable image-recording element comprising
a first element comprising a support carrying a first layer including photosensitive silver halide adjacent to a second layer including photosensitive silver halide, and wherein said first layer includes a silver reducing agent and said second layer does not include any silver reducing agent;
a second element comprising a support carrying an image-receiving layer and in superposed or superposable relationship with said first element, wherein said first layer of said first element is closer to said image-receiving layer of said second element than said second layer of said first element;
a silver solvent located in at least one of said first and second elements; and
means for providing alkali to said first and second elements.

### Claim 8 (depends on 7)

The image-recording element as defined in claim 7 wherein said means for providing alkali includes two reactants which are capable of reacting to form an alkali, one of said reactants being present in said first element and the other of said reactants being present in said second element.

### Claim 9 (depends on 7)

The image-recording element as defined in claim 7 wherein said photosensitive silver halide of said first layer is the same as said photosensitive silver halide of said second layer.

### Claim 10 (depends on 7)

The image-recording element as defined in claim 7 wherein said second element further includes a strip-coat layer positioned on the surface of said image-receiving layer remote from said support.

### Claim 11 (depends on 9)

The image-recording element as defined in claim 9 wherein about two-thirds of the combined amount of photosensitive silver halide is present in said first layer and about one-third is present in said second layer.