JPS6317080A - Duplication method - Google Patents

Abstract

PURPOSE:To duplicate not only a double-surface manuscript or a book but also a thick manuscript as a sharp image, by closely adhering copy paper com prising a thermal film wherein a thermal color forming layer is formed on a substrate to the surface of the manuscript and exposing said manuscript from the copy paper side. CONSTITUTION:Copy paper 1 is formed from a thermal film wherein a thermal color forming layer 3 is laminated to a light pervious substrate 2. The copy paper 1 is arranged so that the thermal color forming layer 3 of the copy paper 1 is opposed to the surface having an image 6a to be duplicated of a manuscript 6 to be contacted with the manuscript 6 under pressure in a mutually closely contacted state, and the manuscript 6 is exposed on the side of the copy paper 1 by an exposure device 7. A part of the light transmitting through the copy paper 1, that is, the thermal film by exposure reaches the background part of the manuscript 6 as shown by the arrow alpha in Fig. 2 to scatter at the background part. The light reaching a line picture part 6a as shown by an arrow betais absorbed by saidl line picture part to generate heat. The heat generated in the line image part 6a transmits to the thermal color forming layer 3 of the copy paper 1 in a close contact with the line picture part to form a color.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying method for directly copying an original image onto copy paper having a thermochromic layer.

Traditionally, the original and transfer paper are brought into close contact with each other with an ink sheet sandwiched between them, and the original is exposed to light from a light source.The image area of the original absorbs the light and generates heat. A thermal transfer method is known in which ink on an ink sheet is melted and transferred onto transfer paper.

In the conventional method, the heat of the light beam from the light source must pass through the original, so it has the disadvantage that it is not possible to copy so-called double-sided originals, books, etc. in which images are printed on both the front and back sides. Further, in the case of thick originals, heat generated in the image area is likely to be dissipated within the original, resulting in a disadvantage that clear copied images cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a copying method that eliminates the drawbacks of the conventional thermal transfer copying method described above, enables double-sided originals and true copying, and allows even thick originals to be copied as clear images.

1. In order to achieve the above object, the present invention corresponds to the line drawings of the original by closely contacting a copy paper made of a thermal film on which a thermochromic layer is formed on the original surface and exposing it to light from the copy paper side. It is characterized by causing coloring to occur on copy paper.

The structure and operation of the present invention will be explained in detail based on the embodiment shown in the drawings.

In FIG. 1(a), copy paper 1 is formed of a thermal film in which a thermochromic layer 3 is laminated on a transparent substrate 2. As shown in FIG. Substrate 2 is made of plastic, synthetic paper, etc.
Formed by a 70 μm thick film, commercially available materials with high transmittance include polypropylene, polyethylene, polyethylene terephthalate or other synthetic paper;
There are also impregnated papers. As the thermochromic layer 3, a layer having a thickness of 1 to 5 μm in which a leuco dye and a color developer are dispersed is used.

The thermochromic layer has low transmittance, so it needs to be as thin as possible, but on the other hand, as the layer becomes thinner, the coloring density decreases, so a thickness of 2 to 3 μm is the optimal example considering both factors. .

The copy paper 1 formed as shown in FIG. 1(a) is placed on the original 6 as shown in FIG. and press them together so that they come into close contact with each other.

An exposure device 7 exposes the copy paper 1 and original 6 that are in close contact with each other from the copy paper 1 side. As the exposure device 7, a flash light source such as a xenon lamp is preferable in order to avoid dispersion of heat that would cause unnecessary portions of the document to generate heat.

A portion of the light transmitted through the copy paper 1, ie, the thermal film, due to exposure reaches the background portion of the original 6, as shown by α in FIG. 2, and is scattered at the background portion. As shown by β, the light beam reaching the line drawing portion 6a is absorbed by the line drawing portion and generates heat. The heat generated in the line drawing portion 6a is transmitted to the thermochromic layer 3 of the copy paper 1 that is in close contact with the line drawing portion 6a, and color is generated. In this way, a copy image corresponding to the line drawing of the original 6 is obtained on the thermochromic layer 3 of the copy paper 1. The image obtained on the thermochromic layer 3 is a normal image when viewed through the transparent substrate 2, that is, when viewed from the side of the light source 7 in FIG. There is no need for further transfer from the paper, and the desired copy can be obtained in a single copying step.

It is also possible to turn the thermal film that is the copy paper 1 upside down compared to the example shown in FIG. is transmitted to the thermochromic layer 3 through the substrate 2, resulting in a large heat transfer loss.

When the image area 6a of the original 6 is made of a thermoplastic material, the first
In FIG. 2, melt mixing or fusion may occur between the image area 6a and the thermochromic layer 3, and when the copy iE1 is peeled off from the original 6, there is a risk of damage to either side. In order to avoid this, it is preferable to use a copying paper 1 in which an overcoat (or protective layer) 4 is provided on the thermochromic layer 3, as shown in FIG. 1(b). In this case, it is necessary to select a material for the overcoat 4 that has good heat resistance, mold releasability, and heat conductivity; for example, a thin film of about 1 to 2 μm thick made of polyvinyl alcohol impregnated with fluororesin is used. used.

An adhesive layer 5 may be provided between the substrate 2 and the thermochromic layer 3 as shown in FIG. 1(c) in order to increase the adhesive strength.

After the thermal film serving as the copy paper 1 is separated from the original 6, if the surface of the base 2 is made the front surface of the copy paper 1, the image can be viewed as an image. In order to facilitate additions to the surface of the copy paper 1 with a writing instrument, it is convenient to make the surface of the base 2 finely roughened by mantle treatment or the like, or to have appropriate hydrophilicity by oxidation treatment. .

The present invention has made it possible to copy double-sided manuscripts, books, etc., and it has also become possible to copy thick manuscripts. Moreover, it has become possible to easily obtain copies without the need for transfer.

By forming an overcoat on top of the thermochromic layer for copying paper, we have improved storage stability, where the coloring gradually fades or the white color of the substrate yellows due to the influence of ultraviolet rays, which occurs with the thermal layer conventionally used in thermal paper. Solvent resistance problems can be solved, such as problems with water and color development when coming into contact with alcohols. It is also possible to color the base or overcoat layer to give it spectral characteristics, thereby giving it the ability to block ultraviolet rays.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of copying paper according to the present invention, and FIG.
The figure is an explanatory diagram of copying work. ■ Copy paper 2 Substrate 3 Thermochromic layer 4 Overcoat 6 Original 6a Image portion 7 Exposure device

Claims (2)

[Claims] (1) A copy paper made of a thermal film with a thermochromic layer formed on a substrate is brought into close contact with the surface of the original, and by exposing the copy paper to light, the copy paper develops a color corresponding to the line drawing of the original. Copying method. (2) The copying method according to claim 1, wherein the exposure is performed by flashing light.