Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1997-04-01
2001-04-03
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S195100, C428S352000, C428S354000, C428S480000, C428S484100, C428S913000, C428S914000
Reexamination Certificate
active
06210794
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermal transfer sheet to be used for a thermal transfer printer utilizing a heating means such as a thermal head and a laser, and more specifically to a thermal transfer sheet which provides good printing quality in thermal printing in full color and has an excellent color reproduction property, and is therefore adapted to be used for a poster, an information board, and to a thermal transfer sheet having improved weatherproofing property, wear resistance and chemical resistance property, in which a plastic substrate as an image receiving sheet to which an image has thermally been transferred with the use of the thermal transfer sheet is adapted to be used for an open-air article such as a license plate for a vehicle such as a car, a road sign, or the like.
2. Description of the Related Art
There has conventionally been known a fusion transfer method in which a coloring agent is transferred to a image receiving sheet such as paper and a plastic sheet by impressing energy corresponding to image information by means of a heating device such as a thermal head with the use of a thermal transfer sheet obtained by carrying a coloring layer or a heat fusible coloring ink layer in which coloring agents such as pigment and dye are dispersed in a binder such as heat fusible wax or resin, on a substrate sheet such as a plastic film.
The transferred image formed by this fusion transfer method has high density and is excellent in clarity, and is therefore adapted to record a binary image such as a character or a line drawing. It is also possible to form a polychrome or color image with the use of decreased kinds of color by making a multiple printing record of coloring layers or heat fusible coloring ink layers on an image receiving sheet by using a thermal transfer sheet having the heat fusible coloring ink layers of yellow, magenta, cyan and the like.
However, there have been many conventional thermal transfer sheets having the coloring layer, in which a wax was used as a binder of the coloring layer, and such conventional thermal transfer sheets had a remarkable problem that image-printed material obtained thereby was poor in wear resistance.
In view of this problem, another thermal transfer sheet has been prepared using a resin as the binder of the coloring layer. When a multiple printing of the coloring layer was conducted with the use of such a kind of the thermal transfer sheet, there was however caused a problem of incomplete printing, i.e., a void or a printing defect on an overlapped portion of the coloring layers.
In the conventional thermal transfer sheet having the heat fusible coloring ink layer, the coloring agents used therein, especially pigments of yellow and magenta do not have a high weatherproofing property. As a result, the indoor normal use of the thermal transfer sheet for materials such as a leaflet or a brochure causes no problem, whereas the outdoor use thereof with its exposure to direct sunlight cause a problem of fading.
SUMMARY OF THE INVENTION
The first object of the present invention is therefore to provide a thermal transfer sheet which permits to solve the above-mentioned problems with the result that a printed material obtained by the thermal printing with the use of the thermal transfer sheet can have a good printing quality without the occurrence of the void and the printing defect on an overlapped portion of the coloring layers, and has an excellent color reproduction property in full color.
The second object of the present invention is to provide a thermal transfer sheet in which a printed material obtained by the thermal printing with the use of the thermal transfer sheet has an excellent weatherproofing property, thus permitting the production of a color image without the occurrence of change such as fading even when the printed material is applied to the outdoor use.
The thermal transfer sheet of present invention for attainment of the aforementioned first object which comprises a substrate sheet, a release layer formed on one surface of said substrate sheet, a coloring layer formed on said release layer and an adhesive layer formed on said coloring layer, is characterized in that said release layer and said adhesive layer are formed from a same kind of material.
According to the above-mentioned thermal transfer sheet of the present invention, by forming the release layer, the coloring layer and the adhesive layer in this order on the one surface of the substrate sheet, it is possible to impart the releasability, coloring property and adhesivity provided by these layer to the thermal transfer sheet so as to carry out effectively these functions. A multiple printing is often conducted with the use of the thermal transfer sheet by carrying out the first thermal transfer step to transfer the first set of the adhesive layer, the coloring layer and the release layer in this order onto the surface of an image receiving sheet and then carrying out the second thermal transfer step to transfer the second set of the adhesive layer, the coloring layer and the release layer in this order onto the release layer of the first set so as to bring the release layer of the first set into contact with the adhesive layer of the second set. When such a multiple printing is conducted, the release layer of the first set and the adhesive layer of the second set which are brought into contact with each other, are fused to form the mixture thereof by heat for the thermal transfer printing, thus improving the adhesivity of the release layer and the adhesive layer and the reproducibility of printed characters in the form of dots, since the release layer and the adhesive layer are formed the same kind of material.
The aforementioned same kind of material may be carnauba wax, polyethylen wax or polyester resin.
The above-mentioned coloring layer may comprise a heat fusible coloring ink layer; and an organic pigment of benzimidazolone-mono-azo may be used as a coloring agent of yellow in said heat fusible coloring ink layer, a mixture of organic pigments of quinacridone-mono-azo and benzimidazolone-mono-azo may be used as a coloring agent of magenta in said heat fusible coloring ink layer, and an organic pigment of phthalocyanine may be used as a coloring agent of cyan in said heat fusible coloring ink layer.
Material mainly comprising resin may be used as a binder in said heat fusible coloring ink layer.
The thermal transfer sheet of present invention for attainment of the aforementioned second object which comprises a substrate sheet and a heat fusible coloring ink layer formed on one surface of said substrate sheet, is characterized in that an organic pigment of benzimidazolone-mono-azo is used as a coloring agent of yellow in said heat fusible coloring ink layer, a mixture of organic pigments of quinacridone-mono-azo and benzimidazolone-mono-azo is used as a coloring agent of magenta in said heat fusible coloring ink layer, and an organic pigment of phthalocyanine is used as a coloring agent of cyan in said heat fusible coloring ink layer.
According to the above-mentioned thermal transfer sheet of the present invention, by using in said heat fusible coloring ink layer the organic pigment of benzimidazolone-mono-azo as a coloring agent of yellow, the mixture of organic pigments of quinacridone-mono-azo and benzimidazolone-mono-azo a coloring agent of magenta and the organic pigment of phthalocyanine as a coloring agent of cyan, it is possible to impart an excellent weatherproofing property to a printed material obtained by the thermal printing with the use of the thermal transfer sheet, thus permitting the outdoor use of the printed material, unlike a printed material obtained by the thermal printing with the use of the conventional thermal transfer sheet, which cannot be applied to such an outdoor use.
Material mainly comprising resin may be used as a binder in said heat fusible coloring ink layer.
A release layer may be formed between said substrate sheet and said heat fusible coloring
Dai Nippon Printing Co. Ltd.
Hess Bruce H.
Ladas & Parry
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