JP2000225781A - Thermal stencil base sheet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print an image to be desired to be printed as an assembly of extrafine pixels by forming a second layer provided at least on one surface of a first layer made of a thermoplastic resin film as a layer obtained by dispersing a low thermally conductive particulate material at a specific value of an areal rate. SOLUTION: The thermal stencil base sheet comprises a liquid absorbing layer 2 on one surface of a first layer made of a thermoplastic resin film 3, a second layer 1 made of a low thermally conductive particulate material dispersed layer on a surface of the layer 2, and a porous support 4 laminated on the other surface of the film 3. In the layer 1, the particulate material constitutes a continued heat insulation area having an areal rate of 50% or above is constituted, and many gaps are constituted in a thermally conductive area. A porous portion 11 is formed as independent segments since it is generated only at a site surrounded by the particulate material. Thus, since a printed matter is obtained as an assembly of fine pixels corresponding to the porous portion, a clear image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil sheet capable of printing an image composed of fine independent pixels, and more particularly, to a heat-sensitive stencil sheet suitable for use in a method of perforating and making a plate by irradiating visible light or infrared light. Related to stencil paper.

[0002]

2. Description of the Related Art Conventionally, as a method for making a heat-sensitive stencil sheet, for example, (1) an original in which characters or the like are handwritten with a writing instrument containing carbon such as a pencil, or a toner image original copied by an electrophotographic method, and A method of superimposing a stencil sheet, heating a character portion or an image portion of the original with light of a flash lamp, an infrared lamp, or the like, and melting and perforating a thermoplastic resin film of the thermosensitive stencil sheet in contact with the stencil sheet, (2) Using a thermal head that generates dot-like heat so as to reproduce an image such as a character according to image information obtained by converting the image into an electric signal, the thermal head is brought into contact with a heat-sensitive stencil sheet, and the thermoplastic resin of the stencil sheet is used. A method for melt-perforating a film is known.

However, in the plate making method of the above (1),
Poor adhesion between the thermoplastic resin film of the heat-sensitive stencil paper and the toner image portion of the original or copy that generates heat may cause perforation failure, or dust on the surface of the original or toner in the non-image portion may generate heat, and However, there is a problem that a portion other than the perforated portion is perforated, that is, a so-called pinhole.

Further, in the plate making method of the above (2), there are problems such as poor perforation due to uneven pressing pressure of the heat-sensitive stencil paper against the thermal head, wrinkling of the heat-sensitive stencil paper, and poor conveyance. was there. further,
In order to efficiently and quickly make and print heat-sensitive stencil paper by the stencil printing method of (2), make the stencil paper with the side opposite to the side where the thermal head comes into contact with the stencil printing ink beforehand. In this case, it is proposed that the ink contacting the heat-sensitive stencil paper increases the non-uniformity of the pressing pressure of the thermal head or that the heat of the thermal head transfers to the ink contacting the heat-sensitive stencil paper. The heat-sensitive stencil paper cannot be provided with a sufficient amount of heat to perforate the heat-sensitive stencil paper, resulting in poor perforation.

In order to improve such a drawback, a heat-sensitive stencil sheet having a liquid absorbing layer and a light reflecting layer is used to reproduce a desired image on a stencil sheet from a liquid discharger by using a liquid containing a photothermal conversion material. To be transferred in the form of dots
A method of irradiating the stencil sheet with visible light or infrared light and selectively perforating a portion to which the liquid has transferred in a non-contact step to make a stencil sheet (Japanese Patent Application Laid-Open No. 9-99664) has been proposed. However, satisfactory results have not yet been obtained in the independence of the perforated dots, and the sharpness of the printed image has also been insufficient.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a heat-sensitive stencil sheet capable of printing an image to be printed as an aggregate of extremely fine pixels. It is in.

[0007]

According to the present invention, the above object comprises a first layer made of a thermoplastic resin film, and a second layer provided on at least one surface of the first layer. The second layer is achieved by a heat-sensitive stencil sheet characterized by being a layer in which low thermal conductive particles are dispersed at an area ratio of 50% or more.

That is, in the heat-sensitive stencil sheet of the present invention, the low thermal conductive granular material has an area ratio of 5 on the surface of the heat-meltable first layer.
It is characterized by having a second layer dispersed at 0% or more. Here, the area ratio means a ratio of a projected area per unit area of the low thermal conductive particles dispersed on the surface of the first layer to the first layer.

Thus, the area ratio of the low thermal conductive particles is 5
When it is 0% or more, the second layer is composed of a heat conductive region having a small area ratio of less than 50% and a large area ratio of 50% or more outside the closed region surrounded by low heat conductive particles. Is formed above the first layer. Therefore, when the heat-sensitive stencil sheet of the present invention is heated from the second layer side during plate making, heat is transferred to the first layer in the heat conductive region constituting the island region, while the continuous sea region is formed. In the heat-insulating region constituting the above, heat is shut off and is not sufficiently transmitted to the first layer. As a result, the first layer is perforated by reaching the melting temperature in the thermally conductive area,
The perforations are made up of a number of segments corresponding to the island regions of the thermally conductive region, since they are kept below the melting temperature in the adiabatic region. Therefore, at the time of printing, since the image is obtained as an aggregate having the segment as pixels, a clear image is obtained.

[0010] The low thermal conductive particles, the smaller the particle size, the more
The island region constituting the heat conductive region can be made fine and numerous, and as a result, each perforated portion can be obtained with a small area, and the printed image is formed as an aggregate of many fine pixels. As a result, the sharpness of the image is improved. Therefore, in general, the average particle diameter of the low thermal conductive particles is preferably 55 μm or less, more preferably 15 μm or less.
m, particularly preferably 5 μm or less. The shape of the granular material may be either a regular shape or an irregular shape, but a regular shape is preferable because a uniform shape of the perforations can be obtained.The narrower the particle size distribution is, the more preferable the shape is. Is more preferable.

Further, the low thermal conductive particles need to have a low thermal conductivity, preferably 1.5 W / m · K or less, more preferably 1.0 W / m · K or less, It is particularly preferred that it be 0.5 W / m · K or less. If the thermal conductivity is too high, the temperature of the first layer will increase in the portion of the heat insulating region due to heat during plate making, as a result, the first layer will be melted and perforated in the region, The area of the perforated area is enlarged, and the sharpness of the image may be impaired.

The heat-sensitive stencil sheet of the present invention is suitable for use in a perforating method for perforating by irradiating visible light or infrared light. In particular, a liquid containing a photothermal conversion material is discharged as droplets from a liquid discharging device. The surface of the heat-sensitive stencil sheet is transferred in the form of dots on the surface to reproduce an image, and the liquid-transferred portion is irradiated with visible light or infrared light to perforate the heat-sensitive stencil sheet to make a plate, JP-A-9-99664. It is suitable for use in a method for making a heat-sensitive stencil sheet as described in (1).

Thus, according to another aspect of the present invention, a liquid containing a light-to-heat conversion material is ejected as droplets from a liquid ejection device and transferred to the surface of the heat-sensitive stencil paper in a dot-like manner, whereby the liquid is In the plate making method of heat-sensitive stencil paper, in which the transferred part is irradiated with visible light or infrared light to pierce and make a heat-sensitive stencil sheet, the heat-sensitive stencil sheet is used as the heat-sensitive stencil sheet. Expression

D ₁ ≦ 100 D ₂ <50 D ₁ (where D ₁ is the average diameter of the dots of each droplet formed on the stencil paper, and D ₂ is the average of the low thermal conductive particles of the stencil paper) Represents the diameter)

[0015] There is provided a method of making a heat-sensitive stencil sheet, characterized in that the stencil sheet is discharged from the liquid discharger to the second layer of the stencil sheet so as to satisfy the above conditions.

In the plate making method of the present invention, the liquid containing the light-to-heat conversion material discharged from the liquid discharging device is transferred to both the heat insulating region and the heat conductive region on the heat-sensitive stencil sheet. Here, when a visible light ray or an infrared ray is applied to the image portion made of the photothermal conversion material reproduced on the surface of the heat-sensitive stencil sheet, the image portion absorbs light and generates heat. When the temperature of the first layer reaches a temperature at which the first layer melts due to the heat generated here, the first layer is perforated. However, if the temperature of the first layer does not reach the melting temperature due to the generated heat, the thermoplastic resin film is not perforated.

Therefore, if the average diameter of the low thermal conductive particles present in each dot formed by the droplet of the liquid containing the photothermal conversion material being transferred on the stencil paper is too large, the low thermal conductivity present in each dot is low. At the same time, the area of each of the heat conductive areas increases as the number of the granular materials decreases, and as a result, the perforated area of the first layer increases. Becomes blurred. On the other hand, if the average diameter of the low thermal conductive particles present in each dot of the droplet is too small, the number of low thermal conductive particles present in each dot increases, and at the same time, the individual area of the thermal conductive region increases. Is reduced, and as a result, the perforated area of the first layer is reduced. When printing is performed using the heat-sensitive stencil sheet made as described above, the ink permeability is reduced, and a printed matter having a low density is obtained. According to the present invention, as described above, the average diameter of each dot droplets of photothermal conversion material containing liquid to form spread to the stencil sheet and D _1, low thermal conductivity granules provided in the heat-sensitive stencil sheet the average diameter of the case of the D _2,
D ₁ ≦ 100 D ₂ <50 D ₁ , preferably D ₁ ≦ 50 D ₂ <20 D
By performing plate making so as to satisfy the relationship of ₁ , a good image can be obtained. This relationship is obtained when the droplets of the light-to-heat conversion material-containing liquid are transferred on the stencil paper and the shape of the dots formed is circular, and the projected shape of the low thermal conductive granular material on the first layer is circular. Most ideally holds. In the plate making method of the present invention, the dots formed on the stencil paper by each droplet of the photothermal conversion material-containing liquid discharged from the liquid discharge device do not need to be independent of the adjacent dots,
They may overlap each other.

Examples of the thermoplastic resin film constituting the first layer of the heat-sensitive stencil sheet of the present invention include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, and polysulfone. A film made of sulfide, polystyrene, polyurethane, polycarbonate, polyvinyl acetate, acrylic resin, silicone resin, or the like is used. These resin components may be used alone or as a mixture, or may be used as a copolymer. Further, the thermoplastic resin film may be white.

The thickness of the thermoplastic resin film is 0.5
5050 μm, preferably 1-20 μm. If the film thickness is less than 0.5 μm, the handleability and strength are poor, and
If it exceeds μm, a large amount of heat energy is required for drilling, which is not economical.

The second layer of the heat-sensitive stencil sheet of the present invention is formed by dispersing or dissolving low thermal conductive granules in water or an organic solvent and mixing the resultant mixture.
It can be obtained by coating on the first layer with a coating means such as a roll coater and drying. The liquid mixture may contain a binder for adhering the low thermal conductive particles to the first layer, if necessary. The binder is
In consideration of being coated with the first layer, it is preferably heat-meltable. The area ratio of the heat insulating region of the second layer is:
It can be controlled by adjusting the concentration of the low thermal conductive granules in the mixture or adjusting the viscosity of the mixture.

The low thermal conductive granules forming the second layer of the heat sensitive stencil sheet of the present invention are made of an inorganic compound (having a thermal conductivity of 0.1 to 0.1).
1.5 W / m · K), organic compounds and organic polymer compounds (thermal conductivity: 0.1 to 0.5 W / m · K), natural fibers (thermal conductivity: 0.03 to
0.07W / mK), natural and synthetic porous materials (thermal conductivity 0.03
To 0.2 W / m · K), and the above-mentioned materials may be used alone or as a mixture. The thermal conductivity of the region is preferably 1.0 W / m · K or less. Further, it is preferable that the granular material is a substance having low light absorption and high light reflectivity with respect to visible light or infrared light in order to prevent heat generation due to irradiated light.

Specific examples of the low thermal conductive granules include talc, clay, calcium carbonate, magnesium carbonate, titanium oxide, aluminum oxide, silicon oxide, zinc oxide,
Fine particles of inorganic compounds such as barium sulfate, lead sulfate and kaolin, organic fine particles of high molecular compounds such as polyurethane, polyester, polyethylene, polystyrene, silicone resin, phenol resin, acrylic resin, benzoguanamine resin, polyurethane, glass wool, cork, wood , Cotton cloth, wool, gas-encapsulated microcapsules, and polyvinylpyrrolidone, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, polyacrylamide, polystyrene, polyethylene, poly Organic polymer compounds such as vinyl acetate, acrylic resin, polyamide, polyester, polycarbonate, polyurethane, chlorinated rubber, and chlorinated polyolefin are exemplified.

The first layer of the heat-sensitive stencil sheet of the present invention is characterized in that when the liquid containing the light-to-heat conversion material is discharged in an image form from the discharge device and transferred onto the heat-sensitive stencil sheet, the transferred liquid spreads and spreads. Further, in order to prevent repulsion and faithfully form a desired image, and in addition to promote absorption and drying of a liquid, a heat-meltable liquid absorbing layer may be provided on the surface thereof.

The liquid absorbing layer is adjusted so that the contact angle between the absorbing layer and the liquid containing the photothermal conversion material is transferred in a range of 20 to 150 degrees, preferably in a range of 30 to 130 degrees. Is done. If the contact angle is less than 20 degrees, the transferred liquid will bleed or spread on the absorbing layer, and if the contact angle is 150 degrees or more, the liquid will be repelled on the absorbing layer, a so-called repelling phenomenon. The absorption layer that satisfies the above range of the contact angle,
It can be prepared by appropriately combining a polymer compound having a high affinity for a liquid containing a photothermal conversion material and a water-repellent compound.

As the polymer compound constituting the liquid absorbing layer, for example, polyvinyl alcohol, methyl cellulose, polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl Pyrrolidone, ethylene-vinyl alcohol copolymer, polyethylene oxide, polyvinyl ether, polyvinyl acetal, polyacrylamide and the like are used. These resin components may be used alone or as a mixture or as a copolymer. Further, if the main component of the liquid containing the photothermal conversion material is an organic solvent, for example, polyethylene, polypropylene, polyisobutylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinyl acetate, acrylic resin, polyamide , Polyimide, polyester, polycarbonate, polyurethane and the like. These resin components may be used alone or as a mixture or as a copolymer.

Examples of the water-repellent compound include fluorine compounds, silane compounds, waxes, higher fatty acids, higher fatty acid amides, and polyolefins. Examples thereof include ethylene tetrafluoride resin and tetrafluoride. Ethylene-propylene hexafluoride copolymer, ethylene tetrafluoride
Perfluoroalkyl vinyl ether copolymer, silicone resin, dimethyl silicone oil, methyl phenyl silicone oil, cyclic dimethyl siloxane, modified silicone oil, carnauba wax, microcrystalline wax, polyethylene wax, montan wax, paraffin wax, candelilla wax, shellac wax , Oxidized wax, ester wax, beeswax, wood wax, spermaceti, stearic acid, lauric acid, behenic acid, caproic acid, palmitic acid, stearamide, lauramide, behenamide, caproamide, palmitamide , Polyethylene, polypropylene and the like. The water-repellent compound is a solid powder,
Any liquid can be used and is contained in the liquid absorbing layer in a dissolved state or a dispersed state.

Further, the liquid absorbing layer may contain organic or inorganic fine particles in order to promote absorption and drying of the liquid containing the photothermal conversion material on the liquid absorbing layer. As the fine particles, for example, organic fine particles of a high molecular compound such as polyurethane, polyester, polyethylene, polystyrene, polysiloxane, phenol resin, acrylic resin, benzoguanamine resin, talc, clay, calcium carbonate, titanium oxide, aluminum oxide,
Fine particles of inorganic compounds such as silicon oxide and kaolin can be used.

The liquid absorbing layer is formed by mixing a liquid obtained by mixing the above polymer compound, the above water repellent compound and, if necessary, fine particles.
It can be obtained by applying the composition on a thermoplastic resin film constituting the first layer by a coating means such as a gravure coater or a wire bar coater and drying the applied resin. In addition, the liquid absorbing layer
It may be provided on the second layer provided on the thermoplastic resin film.

The first layer of the heat-sensitive stencil sheet of the present invention may further comprise a porous support on the side opposite to the second layer. Manila hemp, pulp,
Natural fiber such as mitsumata, mulberry, Japanese paper, polyester,
Examples include thin paper, nonwoven fabric, screen gauze, and the like using synthetic fibers such as nylon, vinylon, and acetate, metal fibers, and glass fibers alone or in combination. The basis weight of these porous supports is preferably in the range of 1 to ²⁰ g / m ² , more preferably in the range of 5 to 15 g / m ² . If it is less than 1 g / m ² , the strength as a base paper will be weak, and if it exceeds 20 g / m ² , the ink permeability during printing may be poor. The thickness of the porous support is preferably in the range of 5 to 100 μm, more preferably 1 to 100 μm.
It is in the range of 0 to 50 μm. If the thickness is less than 5 μm, the strength as a base paper is still weak, and if it exceeds 100 μm, the ink permeability during printing may be poor.

The photothermal conversion material used in the plate making method of the present invention may be any material that can convert light energy into heat energy, and in particular, a material that efficiently converts light energy into heat energy is preferable. As the photothermal conversion material, for example, carbon black, lamp black, silicon carbide, carbon nitride, metal powder, metal oxide, inorganic pigment,
Organic pigments and organic dyes are exemplified. Among these, those having a large light absorption in a specific wavelength region, such as phthalocyanine dyes, cyanine dyes, squarylium dyes, and polymethine dyes, are preferred.

Examples of the liquid containing the photothermal conversion material include aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, ketones, esters, ethers, aldehydes, carboxylic acids, amines, and low molecular complex compounds. Solvents such as ring compounds, oxides, and water are exemplified. Specifically, hexane, heptane, octane, benzene, toluene, xylene, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monomethyl ether, diethylene glycol diethyl Ether, glycerin, acetone, methyl ethyl ketone, ethyl acetate, propyl acetate, ethyl ether, tetrahydrofuran, 1,4-dioxane, formic acid, acetic acid, propionic acid, formaldehyde, acetaldehyde, methylamine, ethylenediamine, dimethylformamide, pyridine, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like. These can be used alone or in combination. If necessary, dyes, pigments, fillers, binders, curing agents, preservatives, wetting agents, surfactants, pH adjusters, and the like can be contained.

As the liquid discharging apparatus used in the plate making method of the present invention, for example, 10 to 2000 (10 to 200
0dpi) Nozzles with openings, slits, porous materials,
A device in which a porous film or the like is connected to a piezoelectric element, a heating element, a liquid feed pump, or the like, and discharges the liquid intermittently or continuously, that is, in a dot or line shape according to an electric signal of a character image. No.

As a device for irradiating visible light or infrared light used in the plate making method of the present invention, a xenon lamp, a flash lamp, a halogen lamp, an infrared heater and the like can be used.

The heat-sensitive stencil sheet of the present invention can be used for general stencil printing after plate making. For example, the ink is placed on one side of the stencil sheet made, and the printing paper is overlaid on the other side, and the ink is pressed, depressurized, passed through the perforated portion by means of a squeegee, etc., and the ink is applied to the printing paper. The printed matter can be obtained by transfer.

As the stencil printing ink, oil-based inks, water-based inks, water-in-oil droplets (W /
O) emulsion ink, oil-in-water (O / W) emulsion ink, hot melt ink, and the like can be used.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 1 is a schematic sectional view schematically showing a specific example of the heat-sensitive stencil sheet of the present invention and a plate making mechanism thereof, and FIG. 3 is a plan view of FIG. The heat-sensitive stencil sheet shown in FIG. 1 includes a liquid absorbing layer 2 on one surface of a first layer made of a thermoplastic resin film 3, and a first layer made of a dispersion layer of low thermal conductive particles on the surface of the liquid absorbing layer 2. It has two layers 1, and further has a porous support 4 laminated on the other surface of the thermoplastic resin film 3.

As is clear from FIG. 3 (a), the second layer 1
The individual particles of the low thermal conductive granules have an average diameter D ₂
, And are arranged substantially vertically and horizontally in a row. Thus, in FIG. 3 (a), the low thermal conductive granules have an area ratio of 5%.
A continuous heat insulating region of 0% or more constitutes a heat conductive region, and a large number of gaps formed between adjacent granules constitute a heat conductive region.

At the time of plate making, as shown in FIG. 1A, droplets of the liquid 6 containing a photothermal conversion material are discharged from the liquid discharging device 5 onto the second layer 1 and transferred to the heat-sensitive stencil sheet. ,
As shown in FIG. 2, the letter F of the alphabet is
It can be reproduced as an aggregate of adjacent circular dots (diameter D ₁ = 6D ₂ ). At this time, as shown in FIG. 1 (b) and FIG. 3 (b) (corresponding to the region A in FIG. 2), each dot of the light-to-heat conversion material 7 is in contact with the upper surface of the granular material of the second layer 1 and the liquid. The transition occurs over the absorption layer 2.

Here, as shown in FIG. 1 (b), when a light source 10 with a light reflecting plate 9 irradiates the second layer 1 with a light beam 10, the photothermal conversion material 7 generates heat. At that time, as shown in FIG. 1 (c), the liquid absorbing layer 2 and the thermoplastic resin film 3
Is not melted at a portion where the granular material of the second layer 1 is present because heat conduction is interrupted, but is caused by heat generated by the photothermal conversion material 7 at a portion where the granular material of the second layer 1 does not exist. The perforated portion 11 is formed by melting, and plate making is performed.

As is apparent from FIG. 3 (c), the perforated portion 11 is formed only as a portion surrounded by the second layer 1, that is, the portion surrounded by the low thermal conductive granules, and thus is formed as an independent segment. That is, even if the photothermal conversion material 7 is transferred to the heat-sensitive stencil sheet of the present invention in a solid image form, the perforated portions 11 of the stencil sheet are obtained as an aggregate of independent perforations. As a result, the printed matter is obtained as an aggregate of fine pixels corresponding to the perforated portion 11, so that a clear image is obtained.

[0042]

Example 1 2 parts by weight of carboxymethyl cellulose and 1 part by weight of aqueous silicone oil were added to a 4 μm thick polyester film.
A mixture of 1 part by weight of silicon oxide, 70 parts by weight of water, and 26 parts by weight of isopropyl alcohol was applied by a gravure coater and dried to form a liquid absorption layer of 0.5 μm.

Next, an average particle size of 4 μm was formed on the liquid absorbing layer.
10 parts by weight of silicone resin powder, 5 parts by weight of acrylic resin, 5 parts by weight of urethane resin, isopropyl alcohol 20
A mixed solution consisting of 100 parts by weight of toluene, 40 parts by weight of toluene and 20 parts by weight of ethyl acetate was applied and dried with a gravure coater so that the area ratio became 60%, to provide a heat insulating region having an application amount of 3 g / m ² .
The area ratio of the heat insulating region obtained here was 60%, and the area ratio of the heat conductive region surrounded by the heat insulating region was 40%. The thermal conductivity of the heat insulating region obtained here was 0.24
It was W / m · K. Next, a Japanese stencil paper having a basis weight of 10 g / m ² was stuck on the opposite side of the film where the heat insulating region was provided to prepare a heat-sensitive stencil sheet.

Then, the heat-sensitive stencil sheet obtained was provided with a light-heat conversion material containing 3 parts by weight of carbon black, 27 parts by weight of propylene glycol, 20 parts by weight of 2-pyrrolidone and 50 parts by weight of water. The liquid is ejected from a liquid ejection device having a 600 dpi resolution nozzle by the letter "F" (see Fig. 2).
Was transferred so that the diameter of one dot constituting the sample was 30 μm. Next, after evaporating the solvent component of the liquid, the image portion is subjected to xenon flash with SP275 (manufactured by Riso Kagaku Kogyo Co., Ltd.), and only the heat conductive region surrounded by the heat insulating region in the image portion of the heat-sensitive stencil paper is obtained. Melted perforation by generated heat,
A heat-sensitive stencil sheet having a perforated portion having an area ratio of 40% in one dot (diameter 30 μm) was obtained.

Next, the heat-sensitive stencil sheet made into a stencil is converted into a stencil printing machine GR375 (Riso Kagaku Kogyo) supplied with ink in advance.
When the printing paper was conveyed while being pressed while rotating the drum, a desired clear printed image was obtained.

Example 2 After a liquid absorbing layer was provided on a 3 μm thick polyester film in the same manner as in Example 1, 10 parts by weight of a benzoguanamine resin powder having an average particle diameter of 3 μm was formed on the liquid absorbing layer. A mixture of 5 parts by weight of polyamide, 5 parts by weight of vinyl chloride-vinyl acetate copolymer, 20 parts by weight of isopropyl alcohol, 40 parts by weight of toluene, and 20 parts by weight of methyl ethyl ketone was coated with a gravure coater so that the area ratio became 70%. And dried to provide a heat insulating region having a coating amount of 3 g / m ² . The area ratio of the heat insulating region obtained here was 70%, and the area ratio of the heat conductive region surrounded by the heat insulating region was 30%.
The thermal conductivity of the heat insulating region obtained here was 0.28 W / m
・ It was K. Next, a Japanese stencil paper having a basis weight of 10 g / m ² was stuck on the opposite side of the film where the heat insulating region was provided to prepare a heat-sensitive stencil sheet.

Next, using the obtained heat-sensitive stencil sheet, in the same manner as in Example 1, the liquid containing the light-to-heat conversion material is transferred in an image-like manner by a liquid discharger, and the transferred portion is flashed with xenon. In the image area of the stencil paper, only the heat-conducting area surrounded by the heat-insulating area is melt-punched by the generated heat, and the area ratio is 30% in the above one dot (diameter 30 μm).
A heat-sensitive stencil sheet having a perforated portion was obtained.

Next, the heat-sensitive stencil sheet made into a stencil is converted into a stencil printing machine GR375 (Riso Kagaku Kogyo) supplied with ink in advance.
When the printing paper was conveyed while being pressed while rotating the drum, a desired clear printed image was obtained.

Example 3 After a liquid absorbing layer was provided on a 4 μm thick polyester film in the same manner as in Example 1, 8 parts by weight of a polyurethane powder having an average particle size of 5 μm was formed on the liquid absorbing layer. 2 parts by weight of silicon oxide powder having an average particle size of 3 μm, polyvinyl butyral 5
Parts by weight, polyamide 5 parts by weight, isopropyl alcohol 4
A mixed solution consisting of 0 parts by weight, 20 parts by weight of toluene, and 20 parts by weight of ethyl acetate was applied and dried with a gravure coater so that the area ratio became 70%, to thereby provide a heat-insulating region having an application amount of 4 g / m ² . The area ratio of the heat insulating region obtained here is 70%,
The area ratio of the heat conductive region surrounded by the heat insulating region was 30%. The thermal conductivity of the heat insulating region obtained here is
It was 0.35 W / m · K. Next, a Japanese stencil paper having a basis weight of 10 g / m ² was stuck on the opposite side of the film where the heat insulating region was provided to prepare a heat-sensitive stencil sheet.

Next, using the obtained heat-sensitive stencil sheet, in the same manner as in Example 1, the liquid containing the light-to-heat conversion material was transferred in an image-like manner by a liquid discharger, and the transferred portion was flashed with xenon. Heat-sensitive stencil paper with perforations with a 30% area ratio per dot (30 μm diameter) in the 1 dot (diameter 30 μm) by melting and perforating due to the heat generated only in the heat-conductive area surrounded by the heat-insulating area in the image section of the stencil paper was gotten.

Next, the heat-sensitive stencil sheet made into a stencil is converted into a stencil printing machine GR375 (Riso Kagaku Kogyo) supplied with ink in advance.
When the printing paper was conveyed while being pressed while rotating the drum, a desired clear printed image was obtained.

[0052]

As described above, the heat-sensitive stencil sheet of the present invention is provided with a layer in which low thermal conductive particles are dispersed at an area ratio of 50% or more. By doing so, perforation is hindered in the region where the low thermal conductive granular material is present, and only the fine region surrounded by the granular material is perforated. Thus, a clear image composed of fine pixels can be obtained at the time of printing.

Further, in a plate-making method in which a liquid containing a photothermal conversion material is transferred from a liquid ejection device as liquid droplets into an image and then radiated with visible light or infrared light, the average particle diameter of the base material having low thermal conductivity is reduced. By controlling the dot diameter of the transferred liquid droplet so as to satisfy a predetermined relationship, a clear image composed of fine pixels can be obtained in the same manner.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view showing a specific example of a heat-sensitive stencil sheet of the present invention in a state in which a liquid containing a light-to-heat conversion material is discharged from a liquid discharge device, and FIG. Shows the state where the light-to-heat conversion material has been transferred and then subjected to light irradiation (a).
(C) is a view similar to (a), showing the heat-sensitive stencil base paper in a state of being made.

FIG. 2 is an enlarged plan view showing a state in which a liquid containing a photothermal conversion material is discharged onto a stencil sheet so as to reproduce the letter “F” in the example of the present invention.

FIGS. 3 (a), (b) and (c) are FIGS. 1 (a) and (b), respectively.
It is a top view of (c).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 second layer 2 liquid absorbing layer 3 thermoplastic resin film 4 porous support 5 liquid ejection device 6 liquid containing light-to-heat conversion material 7 light-to-heat conversion material 8 light source 9 light reflector 10 light beam 11 perforated portion

Claims (7)

[Claims] 1. A first layer comprising a thermoplastic resin film, and a second layer provided on at least one surface of the first layer, wherein the second layer has a low thermal conductive granular material A heat-sensitive stencil sheet characterized by being a layer dispersed at 50% or more. 2. The low thermal conductive granules have a particle size of 55 μm.
The heat-sensitive stencil sheet according to claim 1, wherein: 3. The thermal conductivity of the low thermal conductivity granular material is 1.
The heat-sensitive stencil sheet according to claim 1, wherein the heat-sensitive stencil sheet is 5 W / m · K or less. 4. The heat-sensitive stencil sheet according to claim 1, wherein the base paper further comprises a porous support on a surface opposite to the first layer. 5. The heat-sensitive stencil sheet according to claim 1, wherein the first layer has a liquid absorbing layer on a surface of the thermoplastic resin film. 6. The heat-sensitive stencil sheet according to claim 5, wherein the second layer is provided on a liquid absorbing layer. 7. A liquid containing a light-to-heat conversion material is ejected as droplets from a liquid ejection device and transferred to the surface of a heat-sensitive stencil sheet in the form of dots, and a portion to which the liquid has been transferred is irradiated with visible light or infrared light. In the method of making a heat-sensitive stencil sheet, the heat-sensitive stencil sheet according to claim 1 is used as the heat-sensitive stencil sheet, and the liquid containing the light-to-heat conversion material has the following formula: D ₁ ≦ 100 D ₂ <50 D ₁ (where D ₁ represents the average diameter of the dots of each droplet formed on the stencil paper, and D ₂ represents the average diameter of the low thermal conductive particles of the stencil paper). Wherein the liquid is discharged from the liquid discharging device to a second layer of the stencil sheet.