Stock material or miscellaneous articles – Thermal transfer donor – Multiple layers transfer
Reexamination Certificate
2002-07-24
2004-06-15
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Thermal transfer donor
Multiple layers transfer
C503S204000
Reexamination Certificate
active
06749908
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multicolor heat-sensitive recording material, and more particularly relates to a multicolor heat-sensitive recording material comprising a support having disposed thereon at least three heat-sensitive recording layers.
2. Description of the Related Art
Heat-sensitive recording has developed in recent years because recording apparatus therefor are simple, reliable, and maintenance-free. Materials using the reaction between an electron-donating colorless dye and an electron-accepting compound, and materials that utilize the reaction between a diazo compound or a diazonium salt (may be referred to below simply as “diazo compound or the like”) and a coupler, are widely known as materials for heat-sensitive recording.
The development of multicolor heat-sensitive recording materials in recent years has also been remarkable. Such multicolor heat-sensitive recording materials comprise a support having disposed thereon a yellow-forming layer, a magenta-forming layer, and a cyan-forming layer. A multicolor image is formed thereon by heating the respective layers imagewisely.
Multicolor heat-sensitive recording materials typically employ a combination of a color-forming layer (heat-sensitive recording layer) that comprises an electron-donating colorless dye and an electron-accepting compound and a color-forming layer that comprises a diazo compound or the like and a coupler. Generally, the support is successively disposed with the yellow-forming layer, the magenta-forming layer, and the cyan-forming layer.
Image stability inmulticolor heat-sensitive recording materials can be enhanced by utilizing photodecomposition of the diazo compound or the like to irradiate the entire surface of the heat-sensitive recording material after an image has been formed and thereby fix the image. In order to effectively photofix the image, the lowermost layer (i.e., the layer closest to the support) is often a cyan-forming layer comprising an electron-donating colorless dye and an electron-accepting compound. However, there has been a demand for further improvement of image stability with respect to such photofixable heat-sensitive recording materials.
Another large issue has been to enhance color formability. However, multicolor heat-sensitive recording materials that utilize the reaction between an electron-donating colorless dye and an electron-accepting compound are problematic in terms of image stability because the reaction is an equalizing reaction. Further, because the content of the electron-accepting compound must be higher than that of the electron-donating colorless dye, the color-forming layer that contains the electron-donating colorless dye becomes thicker in comparison with the color-forming layer that contains the diazo compound or the like. A thicker color-forming layer results in a thicker multicolor heat-sensitive recording material, which adversely affects color formability.
There is also a problem with conventional multicolor heat-sensitive recording materials in that, when the upper layers are opaque, fixing light is not effectively utilized and fixation takes longer. Additionally, when the upper layers are opaque, the hues of the color-forming layers become turbid and color reproduction regions shrink.
There is another problem in that whiteness cannot be sufficiently enhanced even if a fluorescent brightener is added.
When conventional multicolor recording materials are used as materials for overhead projectors, there is also a problem in that the background is undesirably colored.
SUMMARY OF THE INVENTION
In view of the problems described above, an object of the present invention is to provide a multicolor recording material that exhibits high sensitivity during fixation, excellent whiteness, and good hues.
Another object of the invention is to provide a multicolor recording material that has high transparency and is suitable for use with overhead projectors.
A first aspect of the invention provides a multicolor heat-sensitive recording material comprising a support having disposed thereon at least a yellow-forming heat-sensitive recording layer, a cyan-forming heat-sensitive recording layer, and a magenta-forming heat-sensitive recording layer, wherein when any one of the heat-sensitive recording layers is disposed on a transparent support and a protective layer is disposed on the any one of the heat-sensitive recording layers, a haze value of the resultant laminate is no greater than 40.
A second aspect of the invention provides a multicolor heat-sensitive recording material comprising a transparent support having disposed thereon a yellow-forming heat-sensitive recording layer, a cyan-forming heat-sensitive recording layer, a magenta-forming heat-sensitive recording layer, and a protective layer, wherein the haze value of the recording material is no greater than 50.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the first embodiment, the multicolor heat-sensitive recording material of the invention at least has a support having disposed thereon at least a yellow-forming heat-sensitive recording layer, a cyan-forming heat-sensitive recording layer, and a magenta-forming heat-sensitive recording layer, and when any one of the heat-sensitive recording layers is disposed on a transparent support and a protective layer is disposed on the any one of the heat-sensitive recording layers, a haze value of the resultant laminate is no greater than 40.
According to this embodiment of the multicolor heat-sensitive recording material, when a laminate is made by sandwiching any one of a yellow-forming heat-sensitive recording layer, a cyan-forming heat-sensitive recording layer and a magenta-forming heat-sensitive recording layer between a transparent support and a protective layer, the haze value of the laminate is no greater than 40. In other words, the heat sensitive recording layers which are designed such that, when a laminate is made by sandwiching any one of the heat-sensitive recording layers between a transparent support and a protective layer, the haze value of the laminate is not greater than 40 are laminated on a support. Because of this construction, the transparency of the heat-sensitive layers becomes higher and the fixing light can be effectively utilized. As a result, the fixing speed is raised. In addition, since every heat-sensitive layer has a high transparency, the color of the recording material does not look turbid.
The multicolor heat-sensitive recording material according to this embodiment may further has an intermediate layer and a light transmittance-adjusting layer. Also in the case where an intermediate layer and a light transmittance-adjusting layer are provided, it is preferable that the haze value of the material produced by laminating, on a transparent support, the intermediate layer or the light transmittance-adjusting layer and a protective layer in that order is no greater than 40. The details of the intermediate layer and the light transmittance-adjusting layer are described later.
The haze value as used herein means the value in percentage (%) obtained by dividing the diffuse transmittance by the total light transmittance (i.e., diffuse transmittance÷total light transmittance×100). The smaller the haze value is, the better the transparency is.
As stated above, if a laminate is made by sandwiching any of the heat-sensitive recording layers between a transparent support and a protective layer, the haze value of the laminate is no greater than 40. This value is preferably no greater than 35 and more preferably no greater than 30. If the haze value exceeds 40, the transparency is lowered and the objective of the invention cannot be achieved.
Examples of the transparent support include synthetic polymer films such as polyester films, e.g., polyethylene terephthalate and polybutylene terephthalate; cellulose triacetate films; and polyolefin films, e.g., polypropylene and polyethylene. These films may be used alone or as laminates thereof.
The t
Edwards N.
Fuji Photo Film Co. , Ltd.
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