Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Structurally defined
Reexamination Certificate
2000-11-03
2004-05-25
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Structurally defined
C430S403000, C430S432000, C430S510000, C430S523000, C430S527000, C430S530000, C430S531000, C430S533000, C430S536000, C430S011000
Reexamination Certificate
active
06740480
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to photographic materials. It particularly relates to photographic base materials containing a clear protective shield for optical and digitally compatible silver halide imaging layers.
BACKGROUND OF THE INVENTION
In the formation of photographic paper it is known that a white pigmented layer is placed directly under the photosensitive silver halide emulsion. The white pigmented layer is typically a polymer such as polyethylene or polyester in which a white pigment such as TiO
2
is dispersed. Such a layer is highly reflective and opaque and enhances the image sharpness of the exposed and developed image. Furthermore, it is known in the art that as the concentration and amount of TiO
2
in the reflective layer under the emulsion is increased, the image sharpness is increased. Sharp images are highly desirable and have significant commercial value.
It has been proposed in U.S. Pat. No. 5,244,861 to utilize biaxially oriented polypropylene sheets laminated to cellulose photographic paper for use as a reflective receiver for the thermal dye transfer imaging process. In the formation of biaxially oriented sheets described in U.S. Pat. No. 5,244,861, a coextruded layer of polypropylene is cast against a water-cooled roller and quenched by either immersion in a water bath or by cooling the melt by circulating chill liquid internal to the chill roll. The sheet is then oriented in the machine direction and in the transverse direction. The biaxial orientation process creates a sheet that has a highly pigmented layer on the topside of a voided layer. The pigmented layer provides a highly reflective layer immediately under the image layer. There remains a need to create an image-sharpening layer that provides additional sharpness to a photosensitive silver halide layer without having to additional expensive white pigment such as TiO
2
. While TiO
2
is highly reflective and desirable, it is very expensive and furthermore tends to scatter light in multiple directions, which tends to corrupt the purity of the photosensitive dyes.
In U.S. Pat. No. 5,866,282 it has been proposed to use biaxially oriented polyolefin sheets laminated to photographic grade paper as a photographic support for silver halide imaging systems. In U.S. Pat. No. 5,866,282 numerous advantages are obtained by the use of the high strength biaxially oriented polyolefin sheets. Advantages such as increased opacity, improved image tear resistance, and improved image curl are obtained. While all of these photographic improvements are possible with the use of biaxially oriented polyolefin sheets, the use of biaxially oriented sheets with solid surface skins for silver halide imaging systems is restricted to the amount of TiO
2
that can be dispersed in the polyolefin polymers, as well as to the practical limitation of the thickness of the pigmented and voided layers.
In reflective photographic papers there is a need to protect the imaging layers from scratches, fingerprints, and stains. Current photographic reflective papers use a gelatin overcoat to protect the imaging layers. While the gelatin does provide some level of protection, it can easily be scratched reducing the quality of the image. Further, fingerprints or stains caused by common household liquids such as coffee, water, or fruit juice can easily stain and distort images. Wiping the images while wet causes undesirable distortion to the gelatin overcoat. Post photographic processing equipment exists that provides a protective coating to the imaging layers. Typically consumer images are individually coated or laminated with a polymer to provide protection to the image layers. A common example is photographic identification badges, which are typically laminated with a clear polymer sheet to provide protection to the image on the identification badge. Post processing application of a protective layer is expensive, as it requires an additional step in the preparation of the reflective print and additional materials to provide the overcoat. It would be desirable if a reflective photographic image could be formed with a protective coating over the developed image layers that could be efficiently applied.
Typically, photographic reflective imaging layers are coated on a polyethylene coated cellulose paper. While polyethylene coated cellulose paper does provide an acceptable support for the imaging layers, there is a need for alternate support materials such as polyester or fabric. The problem with alternate, nonpaper supports is the lack of robustness in photographic processing equipment to mechanical property changes in supports. The photographic processing equipment will not run photographic materials that have significantly different mechanical properties than prior art photographic materials. It would be desirable if a reflective photographic image could be efficiently formed on alternate supports.
U.S. Pat. No. 4,355,099 is concerned with a clear polyethylene In terephthalate film of 20 micrometers that is coated with a silver bromide emulsion and emulsion protective layer. Exposure is through the clear film base. The material is processed and then glued to a white reflective support. While this patent offers some advantages over conventional photographic prints, the polyethylene terephthalate film is also subject to fingerprints, scratches, abrasions and provides little or no fade protection to the photographic dyes against ultraviolet radiation. Viewing of photographic prints subjects them to numerous abuses that can permanently damage a print that make it very unattractive displeasing to the viewer. There remains a need for a more durable photographic imaging element that is resistant to handling damage. Furthermore, U.S. Pat. No. 4,355,099 demonstrates a technique to provide texturing by calendering after the image has been glued to a substrate. One of the inherent problems of applying excessive pressure to an image is distortion of the image, as well as creating a differential thickness of the glue holding top image to the support. This differential thickness can cause problems with the appearance of the image as well as curl and adhesion. In the case where photosensitive silver halide is used, excessive pressure may result in undesired development site causing the picture not to be a true representation of what was captured. There remains a need to provide an improved means of creating a rough surface for a composite print adhered to a reflective backing.
PROBLEM TO BE SOLVED BY THE INVENTION
Photographic materials typically are prone to fingerprinting, scratches, and other handling abuses such as liquid spills. Gelatin used in photographic layers tends to pick up and retain fingerprint oils which render photographic prints objectionable. Fingerprints are particularly objectionable when prints are scanned. Digital artifacts are created when fingerprints are present and their digital removal requires extra work. There remains a need to provide improved photographic materials that are resistant to fingerprints and other abuses.
SUMMARY OF THE INVENTION
It is an object of the invention to improved photographic materials.
It is another object to provide photographic materials that are resistant to fingerprints.
It is a further object to provide photographic materials that are resistant to scratches.
It is an additional object to provide photographic prints that are resistant to liquids.
It is a further object to provide photographic elements that may be easily provided in finished form with a variety of substrates.
These and other objects of the invention are accomplished by a photographic element comprising a transparent polymer sheet, at least one layer containing negative working photosensitive silver halide and at least one upper protective shield to protect the surface of said transparent polymer.
ADVANTAGEOUS EFFECT OF THE INVENTION
The invention provides a photographic element that is highly resistant to handling damage such as fingerprinting, scratches, and liquid spill. Furthermore, the imaging material easily
Aylward Peter T.
Bourdelais Robert P.
Camp Alphonse D.
Eastman Kodak Company
Leipold Paul A.
Schilling Richard L.
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