Radiation imagery chemistry: process – composition – or product th – Transfer procedure between image and image layer – image... – Imagewise heating – element or image receiving layers...
Reexamination Certificate
2002-01-25
2004-12-14
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Transfer procedure between image and image layer, image...
Imagewise heating, element or image receiving layers...
C430S201000, C430S952000
Reexamination Certificate
active
06830863
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a multicolor image-forming material for forming a full color image of high definition with a laser beam, and a method for forming a multicolor image. In particular, the present invention relates to a multicolor image-forming material which is useful for forming a color proof (DDCP: direct digital color proof) or a mask image from digital image signals by laser recording in the field of printing, and a method for forming a multicolor image.
BACKGROUND OF THE INVENTION
In the field of graphic arts, printing of a printing plate is performed by using a set of color separation films formed from a color original by lith films. In general, color proofs are formed from color separation films before real printing work for checking an error in the color separation step and the necessity for color correction. Color proofs are desired to realize high definition which makes it possible to surely reproduce a half tone image and have performances such as high stability of processing. Further, for obtaining color proofs closely approximating to an actual printed matter, it is preferred to use the materials which are used in actual printing as the materials for making color proofs, e.g., the actual printing paper as the substrate and the actual pigments as the coloring materials. As the method for forming color proofs, a dry method not using a developing solution is strongly desired.
As the dry method for forming color proofs, a recording system of directly forming color proofs from digital signals has been developed with the spread of electronized system in preprocessing of printing (pre-press field) in recent years. Such electronized system aims at forming in particular high quality color proofs, generally reproduces a dot image of 150 lines/inch or higher. For recording a proof of high image quality from digital signals, laser beams capable of modulation by digital signals and capable of finely diaphragming recording light are used as recording heads. Therefore, the development of an image-forming material having high recording sensitivity to laser beams and exhibiting high definition property capable of reproducing highly minute dots is required.
As the image-forming material for use in a transfer image-forming method using laser beams, a heat fusion transfer sheet comprising in the order of a support having a light-to-heat converting layer which absorbs laser beams and generates heat, and an image-forming layer which contains a pigment dispersed in components such as a heat fusion type wax and a binder is known (JP-A-5-58045 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)). In the image-forming method using such an image-forming material, an image-forming layer corresponding to the area of a light-to-heat converting layer irradiated with laser beams is fused by heat generated in that area and transferred onto an image-receiving sheet arranged on the transfer sheet by lamination, thus a transferred image is formed on the image-receiving sheet.
Further, a heat transfer sheet (thermal transfer sheet) comprising a support having provided thereon a light-to-heat converting layer containing a light-to-heat converting material, an extremely thin heat-releasing layer (from 0.03 to 0.3 &mgr;m), and an image-forming layer containing a coloring material in this order is disclosed in JP-A-6-219052. In this heat transfer sheet, the bonding strength between the image-forming layer and the light-to-heat converting layer bonded through the intervening heat-releasing layer is reduced by laser beam irradiation, as a result, a highly minute image is formed on an image-receiving sheet arranged on the heat transfer sheet by lamination. The image-forming method by the heat transfer sheet utilizes so-called ablation, specifically the heat-releasing layer partially decomposes at the area irradiated with laser beams and vaporizes, thereby the bonding strength of the image-forming layer and the light-to-heat converting layer at that area is reduced and the image-forming layer at that area is transferred to the image-receiving sheet laminated thereon.
These image-forming methods have various advantages that an actual printing paper provided with an image-receiving layer (an adhesion layer) can be used as the material of an image-receiving sheet and a multicolor image can be easily obtained by transferring images different in colors in sequence on the image-receiving sheet, in particular, the image-forming method utilizing ablation has the advantage that highly minute image can be easily obtained, and so these methods are useful for forming a color proof (DDCP: direct digital color proof) or a highly minute mask image.
DTP is prevailing more and more and the intermediate process using films is omitted when CTP (computer to plate) is used, and the need for proof is shifting from analog proof to DDCP. In recent years the demand for large sized high grade DDCP highly stable and excellent in coincidence in printing has increased. High definition printing can be effected according to a heat transfer method by laser irradiation, and as the laser heat transfer methods, (1) a laser sublimation method, (2) a laser ablation method, and (3) a laser fusion method are conventionally used, but any of these methods has a drawback such that the shape of a recorded dots are not sharp. In (1) a laser sublimation method, since dyes are used as the coloring material, the approximation of proofs to printed matters is not sufficient, further, since this is a method of sublimating coloring materials, the outline of a dot is fuzzy, and so definition is not sufficiently high. On the other hand, since pigments are used as the coloring materials in (2) a laser ablation method, the approximation to printed matters is good, but since this is a method of sputtering coloring materials, the outline of a dot is also fuzzy as in the sublimation method, and so definition is not sufficiently high. Further, in (3) a laser fusion method, a molten substance flows, and so the outline of a dot is not also clear.
SUMMARY OF THE INVENTION
Accordingly, the subject of the present invention is to solve the above-described problems of the prior art techniques and to accomplish the following objects. That is, an object of the present invention is to provide a large sized high grade DDCP which is highly stable and excellent in coincidence in printing. Specifically, the present invention is characterized in that: 1) a heat transfer sheet is a membrane of coloring material which is not influenced by light sources of illumination as compared with pigment material and printed matters, and excellent in sharpness of dots and stability, 2) an image-receiving sheet can surely receive the image-forming layer in a heat transfer sheet by laser energy, 3) transfer to actual printing paper can be effected corresponding to the range of at least from 64 to 157 g/m
2
such as art paper (coat paper), mat paper and finely coated paper, delicate texture can be imaged, and a high-key part can be reproduced accurately, and 4) extremely stable transfer releasability can be obtained. A further object of the present invention is to provide a method for forming a multicolor image which can form an image having good image quality and stable transfer image density on an image-receiving sheet even when recording is performed by multi-beam laser beams of high energy under different temperature conditions.
The present invention has been attained by the following means (1) to (46).
(1) A multicolor image-forming material comprising:
an image-receiving sheet having an image-receiving layer; and
at least four thermal transfer sheets each including a support, a light-to-heat converting layer and an image-forming layer, in which each of the thermal transfer sheets has a different color,
wherein an image is formed by: superposing the image-forming layer in each of the at least four thermal transfer sheets on the image-receiving layer in the image-receiving sheet, in which the image-forming layer is
Goto Yasutomo
Miyake Kazuhito
Shimomura Akihiro
Wachi Naotaka
Yamamoto Mitsuru
Fuji Photo Film Co. , Ltd.
Schilling Richard L.
Sughrue & Mion, PLLC
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