JPS582838B2 - Kannetsuseikohan Insatsuyougenshi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a base paper used for stencil printing, and more particularly to a heat-sensitive stencil paper that is perforated by infrared irradiation.

Conventionally, heat-sensitive stencil printing base paper, which is made by forming a perforated image by irradiation with infrared rays, has a thickness of about 5 to 12 μm.
thermoplastic synthetic resin film and weight approximately 8~12f/
A heat-sensitive stencil printing base paper is known, which is made by bonding with an adhesive a porous support such as Japanese paper having a size of about 2 m2 that allows printing ink to pass therethrough.

To make a plate using this base paper, the film side of the base paper must be closely stacked with the original document, on which an image has been drawn with printing ink such as carbon black that absorbs infrared rays and generates heat, or with a writing instrument. At the same time, infrared rays are irradiated from the base paper side, and the heat generated in the image area of the original document forms a punched image on the film of the base paper at a portion corresponding to the image area of the original document.

In order to obtain printed matter using the stencil plate made in this way, the printing process is usually carried out by attaching the stencil plate to a printing machine such as a rotary copying machine used for stencil printing. .

In this way, plate-making of heat-sensitive stencil printing base paper by infrared irradiation can be performed in an extremely short time, and it can be used to produce a large number of printed materials in a relatively short time using a high-speed printing machine such as a rotary copying machine. Such heat-sensitive stencil printing is widely used in the field of light printing because it has the advantage of being able to print easily and inexpensively using a mimeograph.

However, although there are slight differences in the degree of variation depending on the type of printing ink, the resulting printed matter generally tends to be slightly overexpressed compared to the original image, resulting in a so-called "fatty" printed image. easy to become

That is, the resolution is degraded compared to the perforated image of the original.

Considering the reason for this, in conventional base paper, a synthetic resin film is bonded to a porous support, so when the amount of printing ink required for printing is supplied, even if
Even if the punched image is formed faithfully to the original image, the printing ink is sufficiently impregnated into the porous support, so even if the printing ink is supplied with the appropriate printing pressure, the synthetic resin It is thought that the printing ink flows through the film in an excessive amount, causing a "weight" in the printed image.

This tendency is particularly pronounced for printing inks that flow easily or easily penetrate printing paper; for example, oil-based inks have a stronger tendency to cause printed images to become "heavy" than neutral emulsion inks.

In addition, the porous support is usually used, with a weight of 8~
A problem that occurs when a stencil plate of approximately 12 g/m2 is attached to a rotary copying machine and printing is performed is that in order to make the screen fit better with the printing roller of the rotary copying machine, it is necessary to A relatively large amount of printing ink must be supplied to the printing ink and sufficient pressure must be applied, otherwise the original plate will not adhere to the printing screen and the phenomenon of lifting will occur, resulting in sharp prints. This is something that cannot be done.

This excessive supply of printing ink causes the printing ink to transfer to the back side of the printing paper during high-speed printing.
Problems such as so-called "set-off" may occur, and undried ink may cause poor separation between the printing paper and the printing screen, causing the printing paper to stick to the printing screen. easy.

On the other hand, instead of using a porous support in place of a stencil printing base paper made by laminating such a porous support and a thermoplastic synthetic resin film, it is possible to simply use a sheet of thermoplastic synthetic resin film alone as described above. A perforated image can also be formed by the same means, but when a single film is used as a stencil, since the film is not supported by a support, there is nothing to support the fused portion of the film, and the fused portion There is a problem in that the paper tends to be welded to the image area of the document.

If such welding occurs, in the perforation image, for example,
Images such as 0 and P are easily perforated in a hollow state, and for this reason, it has been difficult in practice to use single film.

The present invention has been made to solve the above-mentioned drawbacks of conventional heat-sensitive stencil printing paper, especially the "fat" defect that occurs during the printing process, and therefore the present invention requires a porous support. An object of the present invention is to provide an improved heat-sensitive stencil printing base paper that does not have the following effects.

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

FIG. 1 is a schematic cross-sectional view showing the structure of the heat-sensitive stencil printing base paper of the present invention.

In FIG. 1, reference numeral 1 denotes a base paper of the present invention comprising a thermoplastic synthetic resin film 2 and a coating film 3, and the coating film 3 is composed of fine powder particles 4 and an adhesive 5.

The heat-sensitive stencil paper having such a structure can be made by using a commonly used infrared irradiation device.

For example, as shown in FIG. 2, the base paper 1 of the present invention is placed on the deck glass 7 of the electronic flash irradiation device 6 so that the coated film 3 side is in contact with it, and the original document 8 is placed thereon so that the image 9 side is in close contact with it. Overlap.

This polymer is pressed from above with a pressing plate 12 consisting of an elastic body 10 and a rigid body 11, and an electronic flash discharge is applied from the base paper side of the polymer, which is installed in a concave reflecting mirror 13 of an electronic flash irradiation device 6. A tube 14 emits a flash of light 15 rich in infrared radiation.

When the base paper is thus irradiated, the light energy absorbed by the image 9 of the original 8 is instantaneously converted into heat, and a perforated image corresponding to the original image is formed on the base paper 1.

The synthetic resin film on which the perforated image is formed is peeled off from the original to form a stencil master.

To create the base paper of the present invention, a thermoplastic synthetic resin film with a thickness of approximately 3 to 30 μm is coated with a powder having a particle size of 100 μm or less and several μm, which is not melted at the melting temperature of the film, and a solvent. Mix the adhesive solution that has been melted into the adhesive, stir well, apply the dispersed solution, and dry.

In this way, a coating film containing powder is formed on the film.

In this case, the coating film containing the powder must have relatively high light transmittance, and therefore the powder itself must not be highly light-absorbing or strongly light-absorbing. .

For example, if powder particles such as carbon black or heavy metal particles that exhibit high light absorption are applied to the entire surface of the film, the entire film will be immediately damaged by light irradiation, so the use of such powder particles is prohibited. I have to avoid it.

However, it is acceptable to mix and use a colorant at a concentration that does not damage the film due to the heat generated when irradiated with infrared rays.

Further, a release agent may be added to the coating film component for the purpose of facilitating separation between the original and the film.

As mentioned above, the powder or granular material can have a particle size in the range of about 100 microns to several microns, but in order to obtain a good perforation image, the particle size is preferably about 50 microns to several microns.

When an adhesive solution in which powder and granules are mixed and dispersed is applied to the surface of a synthetic resin film and dried, some of the particles of the powder and granules protrude onto the surface of the dried adhesive layer, and the particles that the film originally has The surface smoothness is slightly lost and becomes rough, but this maintains an air layer between the deck glass of an electronic flash irradiation machine during plate making and the carrier belt of a thermal copying machine whose light source is a tungsten incandescent lamp, and the synthetic resin It maintains the thermal latent image imparted to the film well, allows clear perforations to be made following the cause, and also helps prevent the fused portion of the film from sticking to the deck glass or carrier belt.

The coating may be applied to only one side of the film, but it may be applied to both sides.

Although the detailed process of perforation in the base paper of the present invention has not been fully elucidated, when observing the molten state of the film under a microscope, the molten resin of the film tends to concentrate around the powder particles. In other words, the particles appear to converge, and compared to the perforations in a stencil plate bonded to a porous support such as conventional Japanese paper, the perforations within the perforation image outline are more circular in shape. formed as a group.

This indicates that the presence of the powder particles Q allows miniaturization of the perforations and equalization of their distribution.

The powder in the base paper of the present invention must be fixed so that it does not move on the film surface, and if the powder moves as in the case of simply sprinkling powder, the powder will When forming a perforation image due to the uneven distribution of the perforation, it is easy to cause perforation unevenness, which is not preferable.

In addition, the dispersion density of the powder in the coating film is not such that the powder covers the entire surface of the synthetic resin film uniformly without any gaps, but rather that the powder and granules do not cover the entire surface of the synthetic resin film uniformly without any gaps, but rather have a density that allows them to be identified as particles, that is, with gaps between the particles. The dispersion density is good enough to be seen.

In other words, this is a density at which the powder material does not substantially block the passage of light.

Further, it is desirable that the dispersion be uniform.

The powder or granules may be either inorganic or organic, but they must not be melted at the melting temperature of the thermoplastic synthetic resin film, and suitable materials include talc, clay, titanium oxide, calcium carbonate, and glass. This includes fine amorphous powder.

The adhesive for fixing the granular material should preferably have relatively high transparency, such as a vinyl acetate adhesive, an acrylic adhesive, a polyvinyl chloride adhesive, or the like.

In addition, the thermoplastic synthetic resin film serving as the substrate of the base paper of the present invention may be a stretched transparent film with a thickness of about 3 to 30 μm in a single layer or a laminated layer, but it is not bonded to a porous support and is a single film. Since it is subjected to printing operations as a film original, it is preferable to use a synthetic resin film with relatively high strength and so-called stiffness in order to facilitate its handling. Examples of such a film include biaxially oriented polypropylene. Examples include, but are not limited to, film, polyester film, and acetate film.

The present invention will be explained in more detail using Examples above.

Example 1 Acrylic ester resin adhesive (trade name, Polysol A
P-50, manufactured by Showa Kobunshi■) 10 parts by weight, bentonite (trade name, S-Ben■ manufactured by Toyojun Yoko) 5 parts by weight, basic dye (trade name, Eisenkathylon Blue GLH, manufactured by Hodogaya Chemical Industry ■) ) and 100 parts by weight of water were mixed and stirred at room temperature to prepare a coating solution.

This was coated on a polyester film having a thickness of 4 μm at a rate of 20 g per square meter using the Mayer bar coating method and dried to obtain a base paper for heat-sensitive stencil printing.

The non-coated side of the base paper and the handwritten manuscript in pencil were closely overlapped, and an electronic flash irradiation device (trade name: Xenofax, manufactured by Riso Kagaku Kogyo ■) was used to flash infrared rays from the base paper side to create a stencil master. .

The small holes within the perforation image outline of the obtained original plate were fine and scattered at a desirable density, and the entire image faithfully represented the image of the original manuscript.

This original plate was printed on a commercially available double-drill rotary copying machine.

During the printing operation, the base paper adhered well to the screen on the printing roller, and about 200 sheets were printed while supplying a commercially available neutral emulsion printing ink, but since the base paper did not have a porous support, printing was difficult. The passage of ink was well preserved, the printing paper did not fly up, and almost no printing ink set-off was observed.

In addition, we were able to obtain printed matter that was faithful to the original image and had no "fat".

Example 2 30 parts by weight of polyvinyl acetate adhesive (trade name, Bond KE-150 manufactured by Gisuke Konishi Shoten), 10 parts by weight of amorphous silica (trade name, Aerosil 2001 manufactured by Nippon Aerosil ■), and 100 parts by weight of methanol. The mixture was mixed and stirred at room temperature to prepare a coating solution.

This was coated to a thickness of 1 by using the doctor blade coating method.
It was coated on a 0 μm polyester film at a rate of 20 g per square meter and dried to obtain a heat-sensitive stencil printing base paper.

The non-coated side of the base paper and the newspaper cutout were closely overlapped, and light was irradiated from the base paper side using the electronic flash irradiation device used in Example 1 to obtain a stencil master in the same manner as in Example 1.

Approximately 200 prints were made using this original plate by printing and drying in the same manner as in Example 1, and as a result, clear prints with no "fet" or "set-off" were obtained in all cases.

Example 3 A coating solution prepared by dissolving 5 parts by weight of a polyvinyl chloride adhesive (trade name, Esdyne 340 manufactured by Sekisui Chemical Co., Ltd.) in 100 parts by weight of water was applied onto a 15 μm thick polypropylene film by the air doctor coating method. Styrene-maleic acid copolymer (trade name, Styrite, manufactured by Daido Kogyo ■) was applied at a rate of 10 g per square meter, and sieved using a 250-mesh sieve cloth on the coated surface where the coating film was not yet dry. The separated fine powder was uniformly scattered at a rate of 2 grams per square meter, and the coating film was completely dried to obtain a base paper for thermal stencil printing.

As a result, the powder particles were distributed only on the surface of the coating layer.

The non-coated side of the above-mentioned heat-sensitive stencil paper and the newspaper clippings are closely overlapped, and a thermal copying machine (product name, Riseau Fax,
A stencil master was created by irradiating infrared rays from the side of the base paper using a stencil (manufactured by Riso Kagaku Kogyo ■).

The perforation state of this original plate was also such that fine small holes were perforated at a uniform density in the portion corresponding to the image area of the original.

When 200 sheets were printed using this original plate by the printing operation of Example 1, the same printed matter as described in Example 1 was obtained.

Example 4 Polyvinyl butyral resin adhesive (trade name, Esdyne 3
60, manufactured by Sekisui Chemical Co., Ltd.), 1 part by weight of calcium carbonate powder, and 100 parts by weight of methanol were mixed and stirred at room temperature to prepare a coating solution, and this was applied to both sides of a 6 μm thick triacetate film on each side. The heat-sensitive stencil paper was coated with a brush at a rate of 5 grams per coat.

The above-mentioned base paper and the pencil-handwritten manuscript were closely overlapped, and a flash was irradiated from the base paper side using the electronic flash irradiation device used in Example 1 to create a stencil master. A perforation image faithful to the image was obtained.

This was applied to the same rotary printing machine as used in Example 1, and ~200 sheets were printed while supplying oil-based printing ink. The printed image was faithful to the image.

[Brief explanation of drawings]

FIG. 1 is a somewhat exploded cross-sectional view showing the structure of the heat-sensitive stencil printing base paper of the present invention, and FIG. 2 shows an example of an embodiment of producing a stencil plate using the heat-sensitive stencil printing base paper of the present invention. FIG. 2 is a somewhat exploded cross-sectional view. 1 - stencil printing base paper, 2 - thermoplastic synthetic resin film,
3-paint film, 4-powder, 5-adhesive, 6-electronic flash irradiation device, 7-deck glass, 8-original manuscript, 9-manuscript image, 10-elastic body, 11-rigid body, 12- pressing plate,
13 - concave reflector, 14 - electronic flash discharge tube, 15 - light beam.

Claims (1)

[Claims] 1. A heat-sensitive film characterized by having a non-strongly light-absorbing powder that does not melt at the melting temperature of the film adhered to the surface of a stretched thermoplastic synthetic resin film at a density that does not substantially impede the passage of light. Base paper for stencil printing.