Stock material or miscellaneous articles – Thermal transfer donor
Reexamination Certificate
2000-06-21
2004-03-09
Hess, B. Hamilton (Department: 1774)
Stock material or miscellaneous articles
Thermal transfer donor
C428S032520, C428S032800
Reexamination Certificate
active
06703087
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermal transfer material which is useful for producing a color proof (DDCP: direct digital color proof) in the field of printing or a mask image due to laser recording on the basis of a digital image signal, and to an image forming material using the thermal transfer material.
2. Description of the Related Art
In the field of graphic art, a printing plate is printed by using a set of color separation films produced from a color original by using a lithographic film. However, prior to main printing (i.e., actual printing operation), in order to check for printing errors which occurred during the color separation process to confirm the need for color correction, and the like, generally, a color proof is produced from the color separation films. It is desirable for the color proof to have high image resolution which allows high reproduceability of a halftone image, and to have qualities such as high stability in various processes. Further, in order to obtain a color proof approximate to an actual original image print, as the material used for the color proof, it is preferable to use materials used for the actual original image print such as printing paper as a base material and a pigment as a color material. Moreover, as a method of producing a color proof, demand is strong for a dry process which does not need a developer.
In a dry process method of producing a color proof, with the recent trend toward increased use of electronic systems in the pre-printing processes (the pre-press field), there has been developed a recording system in which the color proof is produced directly from digital signals. The object of such electronic systems is to produce a color proof of particularly high image quality, and such systems generally reproduce a dot image at a resolution of 150 dpi or more. A high image quality color proof can be recorded from digital signals by using, as a recording head, laser light which can be modulated by the digital signals and which can focus a recording light finely. For this reason, there has been the need to develop a recording material which exhibits a high recording sensitivity with respect to laser light and which exhibits a high resolution capable of reproducing highly accurate dots.
As a recording material which is used for a transfer image forming method using laser light, there has been known a thermally fusible transfer sheet which has a support, and a light-to-heat conversion layer which generates heat due to absorption of laser light, and an image forming layer in which a pigment is dispersed in a component such as a thermally fusible wax or a binder, which layers are provided on the support in that order (Japanese Patent Application Laid-Open (JP-A) No. 5-58045). In an image forming method using these recording materials, a portion of the image forming layer which corresponds to a region of the light-to-heat conversion layer which was irradiated with the laser light is fused due to heat generated at that region. The fused portion of the image forming layer is transferred onto an image receiving sheet which is laminated on a transfer sheet so that a transfer image is formed on the image receiving sheet.
JP-A No. 6-219052 discloses a thermal transfer material which comprises a support, and a light-to-heat conversion layer which contains a light-to-heat conversion substance therein, a heat peel-off layer which is extremely thin (thickness in a range of 0.03 to 0.3 &mgr;m), and an image forming layer which contains a color material which are provided on the support in that order. In this thermal transfer material, adhesive strength between the image forming layer and the light-to-heat conversion layer, which have been adhered to each other by having the heat peel-off layer interposed therebetween, decreases due to the irradiation of laser light. Accordingly, a highly accurate image is formed on the image receiving sheet which has been laminated on the thermal transfer material. The image forming method using the thermal transfer material makes use of so-called “ablation”, and more specifically, makes use of a phenomenon in which, since a portion of the heat peel-off layer decomposes and evaporates at a region of the thermal transfer material which has been irradiated with the laser light, adhesive strength between the image forming layer and the light-to-heat conversion layer at this region weakens, and the image forming layer corresponding to this region is transferred onto the image receiving sheet which has been laminated thereon.
These image forming methods have advantages such as a printing paper on which an image receiving layer (adhesion layer) is provided can be used as the image receiving sheet material, and images of different colors can be transferred one after another onto the image receiving sheet so that a multicolor image can easily be obtained. In particular, the image forming method using “ablation” has the advantage of making it easy to obtain a highly accurate image and is useful for producing a color proof (DDCP: Direct Digital Color Proof) or a highly accurate mask image. To address the demand for images with higher quality in recent years, and to match the progress that has taken place with respect to lasers in recent years, improved sensitivity of the thermal transfer material used in the image forming method and improved image quality obtained by the thermal transfer material used in the image forming method are desired.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a thermal transfer material which has an image forming layer of low fusible viscosity, which has an excellent transferring sensitivity, which is able to form a high quality image, and in which leakage of a thermally fusible substance is not caused so that there is little contamination of hardware such as an image forming device by the thermally fusible substance, and to provide an image forming material using the thermal transfer material.
The present invention is based on the following knowledge obtained by the present inventors, and the means for solving the above-described drawbacks of the conventional art are as follows. The inventors of the present invention carried out extensive studies, and found that, by adjusting the compounded amounts of a resin and a thermally fusible substance which are contained in an image forming layer of the thermal transfer material on the basis of a constant relationship, leakage of the thermally fusible substance from the image forming layer can be effectively prevented while the fusible viscosity of the image forming layer is decreased.
A first aspect of the present invention is a thermal transfer material comprising a support, and on the support, an image forming layer which contains a pigment, at least one thermally fusible substance, and at least one resin, wherein given that a weight ratio of one thermally fusible substance i to one resin j is b
ij
(the weight of the thermally fusible substance i/the weight of the resin j), and an absolute value of the difference between solubility parameter (SP) values of the thermally fusible substance i and the resin j is a
ij
(the absolute value of (SP value of the thermally fusible substance i)−(SP value of the resin j)), b
ij
<(0.03/a
ij
).
A second aspect of the present invention is a thermal transfer material according to the first aspect, wherein the image forming layer contains at least four thermally fusible substances.
A third aspect of the present invention is a thermal transfer material of the first aspect, wherein the thermally fusible substance is selected from the group consisting of higher fatty acids, higher alcohols, fatty acid amides and fatty acid esters.
A fourth aspect of the present invention is a thermal transfer material of the first aspect, wherein a melting point of the thermally fusible substance is from 40° C. to 120° C.
A fifth aspect of the present invention is a thermal transfer material according to the first aspect of the presen
Hatakeyama Akira
Miyake Kazuhito
Nakamura Hideyuki
Fuji Photo Film Co. , Ltd.
Hess B. Hamilton
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