Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-06-13
2002-04-16
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S613000, C430S957000
Reexamination Certificate
active
06372421
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a photothermographic silver halide imaging element containing a blocked inhibitor which is an amido compound, as a contrast enhancer precursor. It further relates to methods of image formation utilizing said element.
BACKGROUND OF THE INVENTION
In photothermographic film systems used to capture full color images, once the film has been developed the scanning of the scene luminance content is only possible over a limited density range, determined by the scanner design. If the film densities are too high, scanning is either not possible or becomes subject to signal to noise problems and scene information is lost. It is essential to design color photothermographic films to have sufficient latitude; that is, to be capable of recording all required scene luminance information in a density range that can be scanned. Therefore, such film designs must have a lower gamma and so reach a lower maximum density in each color record than is normal for conventional films.
It is well known that certain heterocyclic molecules with relatively acidic hydrogen atoms bonded to a ring nitrogen or an adjacent sulfur atom act as development restrainers or inhibitors in photographic film and paper systems. Development inhibitors are utilized to either slow or stop development of silver halide grains. They can be used to correct unwanted dye absorption, improve sharpness and reduce granularity of films. Various methods have been described for chemically blocking these inhibitors, so that they can be stable to storage in the film but can be released in a timely fashion upon development. Release of inhibitor typically is achieved under aqueous alkaline conditions by reaction with base or other nucleophile in the processing solution. In particular, blocked inhibitors have found use in image transfer systems. Research Disclosure article 13118, March 1975 and U.S. Pat. Nos. 4,255,510 and 4,256,881 describe materials that use alkali-hydrolyzable groups to block the inhibitors, specifically N-mono substituted and N, N-disubstituted amido groups. Other methods of non-imagewise release involving reaction of a suitably blocked inhibitor with base or other nucleophile in the processing solution, such as described in U.S. Pat. No. 5,354,650, are known but have not been found useful in photothermography.
In conventional photographic systems, such as color negative films, the addition of free inhibitors, even in small quantities, leads to loss of sensitivity. It is therefore useful to release inhibitors imagewise by chromogenic development using, for example, Development Inhibitor Releasing (DIR) couplers. DIR couplers are used to control film response to light by reducing photographic gamma in an imagewise fashion. However, in many cases DIR couplers are not effective gamma reducers in photothermographic systems.
It continues to be a problem in photothermographic films to provide materials that control photographic gamma and enable wide latitude without a significant loss of sensitivity.
SUMMARY OF THE INVENTION
This invention provides a silver halide photothermographic imaging element comprising at least one silver halide emulsion layer, said silver halide element further comprising an amido compound of Formula I
wherein INH is a development inhibitor;
LINK is a linking or timing group and m is 0, 1 or 2; and
R
1
and R
2
independently are a hydrogen atom or an aliphatic, aromatic or heterocyclic group, or R
1
and R
2
together with the nitrogen to which they are attached represent the atoms necessary to form a 5 or 6 membered ring or multiple ring system, or R
1
and R
2
are independently a —C(═O)(LINK)
m
-INH group, or are substituted with a —NR
3
C(═O)-(LINK)
m
-INH, with R
3
being defined the same as R
1
or R
2
, with the proviso that only one of R
1
and R
2
can be a hydrogen atom.
This invention also provides a method of image formation comprising the step of scanning an imagewise exposed and developed imaging element containing an amido compound to form a first electronic image representation of said imagewise exposure. It further provides a method of image formation comprising the step of modifying said first electronic image representation to form a second electronic image representation and a method of image formation comprising storing, transmitting, printing, or displaying said electronic image representations.
This invention also provides a method of image formation comprising the use of an imaging element containing an amido compound in a one-time-use camera and a method of image formation comprising the step of thermally processing an imagewise exposed element formulated as above in a one-time-use camera having a heater stage.
The amido compounds utilized in the invention provide photothermographic silver halide elements, which have low photographic gamma and long latitude. The amido compounds also provide for balanced responses of the different color records thereby giving similar latitudes for the records. This can lead to simpler, less expensive and potentially more robust film scanner designs, which can enhance dispersed photofinishing options. The amido compounds further provide for enhanced shelf life of the photothermographic film and improved response to temperature variations of thermal processing
REFERENCES:
patent: 3877940 (1975-04-01), Ericson
patent: 3893859 (1975-07-01), Burness et al.
patent: 4255510 (1981-03-01), Simons et al.
patent: 4256881 (1981-03-01), Simons et al.
patent: 4983494 (1991-01-01), Kitaguchi et al.
patent: 5084376 (1992-01-01), Suda et al.
patent: 5354650 (1994-10-01), Southby et al.
patent: 0 218 385 (1987-04-01), None
patent: 2 156 091 (1985-10-01), None
Research Disclosure No. 13118, vol. 131, Mar. 1975, pp. 31-36.
Patent Abstracts of Japan, vol. 013, No. 165 (JP 64002041, Jan. 6, 1989).
Patent Abstracts of Japan, vol. 013, No. 368, (JP 01124852, May 17, 1989).
Owczarczyk Zybslaw R.
Southby David T.
Yang Xiqiang
Chea Thorl
Eastman Kodak Company
Meeks Roberts Sarah
LandOfFree
Photothermographic imaging element having improved contrast... 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 imaging element having improved contrast..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photothermographic imaging element having improved contrast... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2928074