Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2001-09-14
2003-07-15
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S200000, C430S201000
Reexamination Certificate
active
06593060
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a laser thermal-transfer film that is used for the so-called heat mode laser recording method to obtain a highly fine and detailed image by the use of laser radiation, and in particular, to a laser special colors (hereinafter referred to also as special colors) such as white, silver and gold in DDCP (Direct Digital color Proof).
BACKGROUND OF THE INVENTION
In recent years, in the field of graphic arts, there have been proposed DDCPs that output a highly fine and detailed image by using laser radiation, as a digital color proof which can obtain an output equivalent to printing (such as offset printing, gravure printing and so on), by inputting digital data directly, under introduction of CTP (computer to plate). Among them, a recording method of a laser thermal-transfer type employing the same pigment as in printing is attracting public attention, from viewpoints that the same color tone as in printing on printing paper can be obtained, proof-reading is possible, and halftone dots can be
As a color to be used for printing, process colors represented by four colors of yellow, magenta, cyan and black are usually needed, and even in the laser thermal-transfer type recording method, those employing pigments which arc the same as the aforesaid process colors have been developed.
In printing, on the other hand, colors called special colors are also needed in addition to the four colors stated above, as colors to be reproduced in DDCP. For example, there are demanded high-fidelity reproductions for intermediate colors which can be reproduced by color mixture of yellow, magenta, cyan and black, colors which cannot be expressed only by mixing of the aforesaid four colors, and using organic pigments and inorganic pigments accordingly, and colors such as gold, silver and white, which have metallic luster and/or covering power and can be reproduced only by inorganic pigments.
Among the above-mentioned colors, intermediate colors which can be reproduced by using the four colors and colors can be reproduced easily by dispersing and blending pigments and by making them to be contained in an ink layer, in the same way as in yellow, magneta, cyan and black.
However, with regard to special colors which can be reproduced only by using inorganic pigments, various delicate conditions are needed for reproduction of those special colors, and sufficient sensitivity and satisfactory image quality have not been obtained yet, under the existing circumstances.
An object of the invention is to provide a laser reproducing special colors which cannot be reproduced by organic pigments, with texture equivalent to that of printing.
SUMMARY OF THE INVENTION
For reproduction of special colors which cannot be reproduced without using inorganic pigments, he inventors of the present invention have solved the problems mentioned above by changing a design of the structure of an ink layer from that for conventional process color. Namely, the object of the invention has been attained by the following structures.
Structure 1
A laser thermal-transfer to transfer an ink image by being imagewise exposed with a laser beam, comprising: a support; a light-heat conversion layer; and an ink layer having at least one kind of a thermoplastic resin and a pigment,
wherein an average transmittance of the ink layer for a light having wavelength of 350 to 650 nm is not more than 70% and L* value of the ink layer is not less than 60.
Structure 2
The laser thermal-transfer film according to the above structure 1, wherein the ink layer comprises the thermoplastic resin of 10% by weight or less and the density of the ink layer is 1.2 to 4 kg/l.
Structure 4
The laser thermal-transfer film according to the above structure 1, wherein the ink layer comprises the thermoplastic resin of 77% by weight or less and the pigment of 20% by weight or more, and the density of the pigment is 2.0 kg/l or more.
Structure 4
The laser thermal-transfer film according to the above structure 1, wherein the pigment comprises at least one compound selected from the group consisting of a titanium compound, an aluminum compound, a lead compound, a silver compound, a molybdenum compound, an iron compound, a copper compound and a zinc compound.
Structure 5
The laser thermal-transfer film according to the above structure 1, wherein the thermoplastic resin comprises a first thermoplastic resin having a melting point or a softening point of 140° C. or less and a second thermoplastic resin having a melting point or a softening point of 150° C. or more, and the ink layer contains the first thermoplastic resin of 8 to 55% by weight and the second thermoplastic resin of 2.0% by weight or more.
Structure 6
The laser thermal-transfer film according to the above structure 1, wherein dispersion average diameter of the pigment is not more than 2.0 &mgr;m.
Structure 7
The laser thermal-transfer film according to the above structure 1, wherein the thickness of the ink layer is not more than 2.0 &mgr;m.
Structure 8
The laser thermal-transfer film according to the above the structure 1, wherein the weight of the ink layer is not less than 0.8 g/m
2
.
Structure 9
The laser thermal-transfer film according no the above structure 1, wherein an average transmission density of the ink layer for a light having a wavelength of 350 to 650 nm is not more than 0.0.
Structure 10
The laser thermal-transfer film according to the above structure 4, wherein the pigment comprising at least a dioxide, aluminum powder and bronze powder.
Structure 11
The laser thermal-transfer film according to the above structure 1, wherein the laser thermal-transfer film further comprises a cushion layer between the support and the light-heat conversion layer.
DETAILED DESCRIPTION OF THE INVENTION
A laser thermal-transfer film of the invention is a film having at least a light heat converting ability and an ink (coloring material) transferring ability, and it can be provided, when necessary, with an easy adhesion layer between a light-heat conversion layer and a support as well as an intermediate layer between the light-heat conversion layer and an ink layer, and the layer thermal-transfer film can further be provided, when necessary, with a back coating layer on the side opposite to that for the easy adhesion layer and the intermediate layer.
An ink layer related to the laser thermal-transfer film of the invention will be explained as follows.
The ink layer related to the invention is characterized to contain at least one typo of a thermoplastic resin and a pigment. In a laser thermal-transfer method, the ink layer is a layer that is melted or softened through heating and can be transferred in a form of a layer containing coloring agents and thermoplastic binders, which makes it unnecessary to transfer in the state of perfect melting.
In the invention related to Structure 1, an ink layer is characterized to contain at least one type of a thermoplastic resin and a pigment, and its average transmittance of the ink layer for a light having wavelength of 350 to 650 nm is not more than 70% and L* value is not less than 60. By setting average transmittance of the ink layer for the light having wavelength of 350 to 650 nm and L* value of the ink layer to be within the conditional range of the invention, it is possible to attain excellent color reproducibility for special colors and to obtain excellent image quality. Further, for obtaining color reproducibility which is more excellent, it is preferable to make average transmittance of the ink layer for the light having wavelength of 350 to 650 nm to the ink layer to be within a range of 44-60% and L* value is not less than 70.
The average transmittance (T %) mentioned in the invention is one obtained by averaging transmittance in the wavelength area of 350-650 nm, and it can be obtained by the following method.
A sample wherein an ink layer coating solution is coated as dry mass of 2.0 g/m
2
on a 35 &mgr;m-think polyethylene terephthalate support is prepared, and its transmittance is measured from the direction of th
Konica Corporation
Muserlian Lucas and Mercanti
Schilling Richard L.
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