JPS6325959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mimeograph base paper used in mimeograph printing, and more particularly to a mimeograph base paper that can be plate-made by a thermal method.

The mimeograph base paper (hereinafter referred to as base paper) used for mimeograph printing is usually Gampi paper treated with paraffin, or porous and strong Japanese paper such as Tengujiyo, coated with gelatin or collodion and castor oil. A material with a coating is used. These base papers are made into plates by removing coatings using an iron brush, a brush, or a typewriter, respectively, by friction, writing with a weakly acidic liquid, or printing pressure. For this reason, in addition to requiring a considerable amount of time to make the plate, there was also the drawback that it was not possible to make the plate from photographs, newspaper clippings, and miscellaneous paper clippings as manuscripts.

In order to eliminate these drawbacks, a base paper has been proposed that can be subjected to plate making by selectively applying heat pulses. This base paper can be made into plates in a short time using a thermal transfer recording device, and furthermore, figures or pictures can be made into plates at will according to the image information supplied to the device.

FIG. 1 shows the cross-sectional structure of this proposed base paper. The base paper 10 is a porous base material 1
1 is coated with a heat-sensitive material layer 12. As the porous base material 11, for example, Ganpi paper, which is handmade Japanese paper made from bark, is used.
The heat-sensitive material layer 12 is fixed at room temperature,
A material that sublimates or becomes fluid when heated is used. Examples of such waxes include waxes such as paraffin wax and rice wax.

Figure 2 shows the principle of plate making for this proposed base paper. The base paper 10 is stacked with the heat-sensitive material layer 12 side on the transfer medium (plain paper) 21, and the porous base material 11 side is placed on the thermal head 2.
2. In this state, thermal head 2
2 and a cross crawler 23 located at a position opposite to
is rotated in the direction of the arrow while being pressed against the transfer medium 21, and the thermal head 22 is driven at the same time. As a result, the base paper 10 and the transfer medium 21
are superimposed and sub-scanned in the right direction in the figure. At this time, the heat-sensitive material layer 12A corresponding to the part of the thermal head 22 where heat is generated is transferred to the transfer medium 21, and the heat-sensitive material layer 12B corresponding to the part where no heat is generated is transferred to the porous base material 1.
1 remains on top. The base paper 10A consisting of the porous base material 11 and the heat-sensitive material layer 12B is separated from the transfer medium 21 and used as a stencil for mimeograph printing.

However, in the proposed manuscript 10, due to the characteristics of the porous base material 11, a part of the heat-sensitive material forming the heat-sensitive material layer 12 may seep into the porous base material 11 to some extent during manufacturing. It was inevitable that it would happen. The heat-sensitive material soaked into the porous base material 11 is not easily transferred to the transfer medium by the heat pulse supplied from the thermal head 22. Therefore, the heat-sensitive material remains on the base paper 10A after making the plate even in areas where the mimeograph ink should penetrate (hereinafter referred to as exposed areas), causing deterioration of printing characteristics.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mimeograph base paper in which no heat-sensitive material remains in the exposed portion of the porous base material.

In the present invention, the above-mentioned purpose is achieved by using a mimeograph base paper in which the surface of a porous base material is coated with a layer of heat-sublimable material, and further coated with a layer of heat-sensitive material that is solid at room temperature but becomes fluid when heated. achieve.

The present invention will be explained in detail with reference to Examples below.

FIG. 3 shows the cross-sectional structure of the base paper. The base paper 30 has a three-layer structure in which a heat-sublimable material layer 31 is formed on the surface of a porous base material 11, and a heat-sensitive material layer 12 is further formed thereon. As the porous base material 11, Gampy paper with a thickness of about 50 μm is used. The heat sublimable material layer 31 contains, for example, nitro dye, monoazo dye, disazo dye, etc.
A film with a thickness of 10μ to 15μ was formed by a solvent method. On top of this, a heat-sensitive material layer 12 made of wax such as paraffin wax or rice wax is formed as a film with a thickness of 10 to 15 microns by the hot melt method. The heat-sensitive material layer 12 is completely prevented from penetrating into the porous base material 11 due to the presence of the heat-sublimable material layer 31. The overall thickness of the base paper 30 is generally preferably selected between 10μ and 100μ in view of the required strength and transferability to the transfer medium.

Figure 4 shows the principle of plate making using this base paper. The base paper 30 and the transfer medium 21 are superimposed on each other such that the heat-sensitive material layer 12 side contacts the transfer medium 21 . These stacked sheets 21 and 30 are moved in the sub-scanning direction by the back roller 23 with the porous base material 22 side in contact with the thermal head 22.

Now, a portion 31A of the heat sublimable material constituting the heat sublimable material layer 31 of the base paper has soaked into the vicinity of the surface of the porous base material 11. Therefore, when the thermal head 22 is driven and a heat pulse is selectively applied to the base paper 30, the heat-sensitive material layer 12A in the areas to which the heat pulse has been applied and a portion of the heat-sublimable material layer 31B in these areas are heated. The image is transferred to the thermal transfer medium 21. A portion of the heat-sublimable material 31A remains soaked into the inside of the porous base material, and a heat-sensitive material layer 12B and a heat-sublimable material layer 12B remain in the area where the heat pulse was not supplied. The remainder of the layer 31C remains on the porous base material 11.

After the recorded base paper 30A is separated from the thermal recording medium 21, its surface is uniformly heated by a heating means such as an infrared lamp 41. At this time, a portion 31A of the thermally sublimable material remaining in the exposed portion 42 is completely sublimated and disappears. Further, the heat-sensitive material layer 12B remaining on the porous base material 11 penetrates into the porous base material 11 by melting. As a result, base paper 3
With 0A, the mimeograph ink penetrates better and good printing characteristics can be obtained.

As explained above, according to the present invention, a high-quality base paper can be obtained by a simple operation of coating the surface of a porous base material of a mimeograph base paper with a heat-sublimable material layer and a heat-sensitive material layer.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of a conventionally proposed base paper, FIG. 2 is a principle diagram showing the principle of plate making using this base paper, and FIG. 3 is a sectional view showing the structure of a base paper in an embodiment of the present invention. FIG. 4 is a principle diagram showing the principle of plate making using base paper in this embodiment. DESCRIPTION OF SYMBOLS 11... Porous base material, 12... Heat-sensitive material layer, 30... Mimeograph base paper, 31... Heat-sublimable material layer.

Claims (1)

[Claims] 1. A porous base material into which mimeograph ink penetrates, a heat sublimable material layer formed with a material that sublimes by heating to a substantially uniform thickness on one side of the base material, and a heat sublimable material layer on the heat sublimable material layer. A mimeograph base paper comprising: a heat-sensitive material layer formed with a substantially uniform thickness of a material that is solid at room temperature and becomes fluid when heated.