Radiation imagery chemistry: process – composition – or product th – Dye image from radiation sensitive dye or dye former by dry... – Multiple image formation – multiple image exposure – or...
Reexamination Certificate
2002-07-15
2004-02-24
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Dye image from radiation sensitive dye or dye former by dry...
Multiple image formation, multiple image exposure, or...
C430S337000, C430S363000, C430S962000
Reexamination Certificate
active
06696229
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a dry photographic printing process, based on the use of photochromic materials, which permits to obtain high quality photographs by means of conventional electronic equipment. The invention is also applicable to the reproduction of color prints.
BACKGROUND OF THE INVENTION
Photochromic materials, viz. materials which are colorless, but develop colors when irradiated with light of specific wavelength, have been known in the art for a long time. Each photochromic material is sensitive only to a given light wavelength and will not acquire color if it is irradiated with light of a different wavelength.
The light sensitivity of photochromic materials has led to new types of self-developing and dry photography, which are known in the literature for more than 20 years. They are used as color-forming components in photochromic and free radicals, photographic materials with a sensitivity of 10-4 j.cm
−2
(see Photochronism, R. C. Bertelson, Willy Interscience New York, Ed C. H. Brown (1971) and A. L. Kartuzhaqnsi (Ed), Non-silver photographic processes, Izd. Khimiya, Leningrad 1984).
The photochromic materials are also used in the technology of photomasking and photoresist (see P. L. Foris (N.C.R.), U.S. Pat. No. 3,346,385, 1967, and M. Orlovoic, E. Stone and J. M. Pearson, J. Electrochem. Soc., 116 (1969), p. 1464).
Many applications in the field of imaging and reprography systems have been suggested using metal salts and different supports or reactants.
A record sheet for thermographic copying or hot stylus recording has a coating consisting of an intimate Ore of solid calcium resinate and 4′,7′,8′-trimethoxy-BIPS. These react upon melting to give a stable, deep blue color, and various colors can be obtained from other combinations of cations and spiropyrans (see H. H. Baum, U.S. Pat. No. 3,293,055, 1966; L.D. Taylor, Polaroid, U.S. Pat. No. 3,320,067,“Composition and process utilizing photospirans”, 1967; P. L. Foris, U.S. Pat. No. 3,341,330,“Methods of forming thermally stable photochromic dyes and products”, 1967; W. J. Becker and P. L. Foris, U.S. Pat. No. 3,364,023, 1968).
The influence of a polymer on the characteristics of the photochromic transformation, and the possibility of stabilizig the colored form by selecting the appropriate polymer or the type of chemical binding of the spiropyran to the latter, are discussed by M. Kryszenski, B. Vadovski and R. IuhoLf, Macromol. Chem., 183 (1982), p. 1257; G. Smets, J. Brackem and M. Iril, Pure Appl. Chem., 50 (1978), p. 1979; and M. Le Baccon, F. Garnier and R. Guglielmetti, Bull. Soc. Chim. Fr. (1979), p. 315.
When paper or plastic materials containing a spiropyran are irradiated through a negative transparent original, colorless spiropyrans is transformed, in the region exposed to ultraviolet radiation, into colored photomerocyanine set in this form by the vinylic polymer of binder. This process yields a negative image of the original (see Z. G. Gardlund and J. J. Laverty, J. Polym. Sci., B 7(1969), p. 719; and C. Ceintrey, R. Guglielmetti and M. Le Baccon, French Patent Application No. 76.15336, 1976).
As is well known, different colors may be obtained by additive synthesis or subtractive synthesis, which are both conventionally used, e.g. in color printing. This invention will be described as based on additive synthesis, but subtractive synthesis is not excluded. Further, the colors used for the synthesis could be the basic colors—magenta, yellow and cyan—or the complementary colors—respectively green, red and blue—or, in particular cases, other combinations of colors. In describing this invention, it will be assumed that complementary colors (briefly, the RGB system) are used, but this is not to be construed as a limitation. Any method or procedure known in the art for the production of desired colors by additive or substractive synthesis can be used in carrying this invention into practice.
Despite the extensive knowledge of photochromic materials which is available in the art, no satisfactory photographic process based on their use has been developed so far.
It is the purpose of this invention to provide such a process for dry printing and photography.
It is an another purpose to provide such a process that produces stable prints.
It is a further purpose to provide such a process that produces high quality photographs.
It is a still further purpose to provide such a process that can be carried out by using conventional electronic equipment.
It is a still further purpose to provide such a process that can be used for the reproduction of printed color images.
It is a still further purpose to provide personalized printing, in which changes in a part or all of the output can be effected as a function of a predetermined rule, to prevent counterfeiting.
SUMMARY OF THE INVENTION
The process of color photography or reproduction of color prints according to the invention comprises the steps of:
a—providing a substrate having at least three and preferably four superimposed layers, including photochromic materials sensitive to light wavelengths different from layer to layer;
b—scanning the object to be photographed or reproduced;
c—generating from the scanning a digital file defining the image of the object, to be created on the photograph or reproduced;
d—providing at least three and preferably four sources of laser light having different wavelengths, each of which is the wavelength to which one of said photochromic materials is sensitive, while the other photochromic materials are not sensitive to it; and
e—irradiating the substrate by means of the laser beams produced by said sources, according to a program determined by said digital file, whereby to develop in each pixel of the substrate the color that it has in said image.
Any substrate layer that is not irradiated or is irradiated with a light wavelength to which the color of the layer is not is sensitive, is unaffected and if or where transparent, it remains transparent. In the following description, it will be assumed that the RGB system is used and therefore the aforesaid substrate layers include photochromic materials which, when irradiated by the appropriate light wavelength, will produce in each layer one of the aforesaid complementary colors: red, green and blue, and optionally, in one layer, black. However, this is not intended to be a limitation, and, for example, the basic colors magenta, yellow and cyan might be produced.
The digital file, defining the image, may be obtained by scanning the object to be photographed, viz. by scanning in vivo. Thus, e.g., a digital file representing the face of a person can be obtained by scanning said face. This technique and the scanner apparatus for carrying it out are well known. The results of the scanning is a file which determines the color of each pixel of the photograph. If the invention is used for reproducing a color print, the color print will be scanned.
Once the digital file has been created, the laser beam sources are controlled by it, to develop the appropriate color in each pixel of the substrate by generating and directing onto said pixel the laser beam the wavelength of which sensitizes the photochromic material which, when sensitized, assumes said appropriate color. Though black is not properly a color, what is said herein about the colors applies to it as well. In other words, the digital file will control the laser sources in such a way that if a given color is desired to be developed at a given pixel, it will activate the laser beam that develops said color when impinging on one of the layers of the substrate including a photochromic material (hereinafter, briefly, “a photochromic layer”). If the photochromic layer which develops said color is not the top one, the laser beam will cross the superimposed layers without affecting them in any way, because the photochromic materials of said superimposed layers are not sensitive to the wavelength of said beam and therefore said layers will be and remain transparent. It will be understood that, whe
Dukler Shlomo
Hassan Jacob
Meerfeld Yaron
Altera Law Group LLC
Kromotek, Ltd.
Schilling Richard L.
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