JP2002154282A - Base paper sheet for thermal stencil printing and plate perforating method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base paper sheet for thermal stencil printing, in which troubles such as the development of wrinkles during the thermal perforation of the base paper sheet for thermal stencil printing and the deterioration of the dimensional accuracy of a perforated image are solved. SOLUTION: This base paper sheet for thermal printing has a thermoplastic resin film, which is perforated with the heat source of a thermal head or the like by the energy of 0.001 mJ/dot to 1.000 mJ/dot under the state that shrinkage percentages in a subscanning direction and in a main scanning direction of the base paper sheet for the thermal stencil printing after being perforated with all the dots are set to be within ±1.00%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique in the field of digital stencil printing. More specifically, the present invention relates to a thermoplastic resin film alone or an original plate obtained by coating a thermoplastic resin film with a porous resin film, or an original plate thereof. The present invention relates to a heat-sensitive stencil printing plate in which a reinforcing material is provided on the plate.

[0002]

2. Description of the Related Art Conventionally, in digital stencil printing, a thermoplastic resin film (hereinafter, referred to as a laminate) on a support such as paper.
A thermal head in which fine heating elements are arranged in a horizontal line is brought into contact with a film (abbreviated as film), and the heating elements are pulsed to form holes, and then ink is exuded from the holes to perform printing. . The thermal head used here is an electronic component that outputs an electric signal as heat, for example, thermal transfer printing for transferring an ink layer from an ink transfer ribbon or an ink transfer sheet to paper or printing in which the image receiving paper itself develops heat. Widely used in printers and the like that perform

The heat generation characteristic distribution on the thermal head at the time of plate making is such that, when focusing on one heating element, the temperature at the center of the heating element is the highest (EX 300 ° C. or higher), and the temperature decreases as it goes to the periphery. Become. In addition, when continuous heat generation is performed, thermal overlap occurs between each heat generation element and the next heat generation element to be perforated.

Therefore, when a stencil sheet or the like using a single heat-sensitive film is perforated with a thermal head or the like to make a stencil, heat is applied to a surface other than the heating element (including a time lag in the master transport direction). ), Heat shrinkage of the film occurs in the unperforated portion, resulting in plate making distortion, resulting in a problem that the image shrinks from the target image.

[0005] Due to the above-mentioned problems, the above-mentioned problems have been prevented by using a conventional heat-sensitive stencil sheet using a porous support. In such base paper, there is a difference in the strength of the support in the order of a porous support mainly composed of natural fibers (Japanese paper)> a porous fiber membrane mainly composed of synthetic fibers (reinforcing material)> a porous resin membrane.

In this method, thermal shrinkage of the film is suppressed by the presence of the support, and no problem such as generation of wrinkles on the image occurs. (Because the strength of the support is larger than the force generated by heat shrinkage of the film)

However, when a support-less original film is used, when a support having a low strength is used, or when a porous resin film is used, there is no support, so that when a heat is applied, Deterioration of the dimensional accuracy of the plate-making image due to heat shrinkage of the unperforated portion of the heat-sensitive film, and plate-making wrinkles (printing image defects) caused by the deterioration have occurred as problems.

Japanese Patent Application Laid-Open No. Hei 5-116215 discloses a technique in which a high heat shrink film is used to increase the sensitivity, but does not satisfy all of the above requirements. Similarly, Japanese Patent Application Laid-Open No. 7-14448
Japanese Patent Publication No. 8 proposes a technique for preventing the base paper curl by defining the value of the heat shrinkage at 50 ° C. of the film, but does not satisfy all the above requirements.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive stencil in which the above-mentioned problem of wrinkles generated when heat-sensitive stencil printing stencil is thermally made and a problem of deterioration in dimensional accuracy of a plate-making image are solved. To provide printing base paper.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, completed the present invention. According to the detailed studies by the present inventors, the heat shrinkage of the film is appropriately controlled at the time of thermal plate making, and even if a base paper using a support-less base paper or a porous resin film or a porous fiber membrane is used, the entire base paper can be used. The heat shrinkage of the base paper is prevented, and the film remaining portion (unperforated portion) in the image forming portion of the base paper does not shrink by the heat source such as a thermal head, and as a result, the dimensional reproducibility of the image forming portion of the film is good. And a method for making a heat-sensitive stencil sheet in which the size of the hole to be formed is optimal. Here, the sub-scanning direction is a direction (vertical direction) perpendicular to the direction in which the heating elements are arranged in a horizontal row (main scanning direction).

That is, the inventors of the present invention have made a heat-sensitive stencil sheet having a thermoplastic resin film into a stencil sheet of 0.001 mJ / dot-1.
When perforated with an energy of 000 mJ / dot and all dots are perforated in the thermosensitive stencil sheet, the expansion / contraction ratio of the thermosensitive stencil sheet in the sub-scanning direction and the main scanning direction after perforation is within ± 1.00%. , Preferably -0.80 to +0.
80, and more preferably −0.60 to +0.60, by using a heat-sensitive stencil sheet having a stencil width of −0.60 to +0.60, and find that fine lines due to wrinkles do not occur on the printed image. Was.

The expansion ratio of the heat-sensitive stencil sheet of the present invention is determined by the following method. The heat-sensitive stencil sheet is thermoplated, observed with a microscope, and the distance between the center points of a large number of independently perforated holes is measured for 20 dots as black solid portions, and a black solid portion is formed from the results. The expansion and contraction rate of the perforated image is obtained by the following equation. (Stretch ratio)

[0013]

## EQU3 ## Expansion / contraction ratio (%) = (l−L) / L × 100 L: Standard dimensional value between the center point of the left end dot and the center point of the right end dot for 20 dots of the heating elements arranged in a row. Distance l: The measured value, the center point of the upper end (left end) hole and the center point of the lower end (right end) hole of 20 independent holes formed in a vertical (horizontal) line formed on the plate making film by the 20 dots of the heating element. Distance between.

Further, the present inventors have found that the value of the heat shrinkage ratio of the unperforated portion of the film is 1 within the temperature range of T1 shown below.
5% or less, preferably 0% to 12%, more preferably 0%
% To 10%, it has been found that fine lines due to wrinkles do not occur on the printed image.

[0015]

Tc <T1 <Tm _1/2 Tc: Thermal shrinkage onset temperature of the film Tmp: Melting point of the film Tm _1/2 : Intermediate (1/2) temperature between Tc and Tmp Thermal shrinkage: Predetermined temperature If the heat shrinkage after 10 minutes is more than 15%, a dimensional change due to the heat shrinkage occurs, and a fine line due to wrinkles on the film occurs on the image, and the printed matter faithfully reflects the original image Can not be obtained.

The method for measuring the heat shrinkage and the temperature in the present invention is as follows. (Thermal shrinkage) A film sample of a fixed size (10 cm × 10 cm) was prepared at each temperature (... 60 ° C., 70 ° C., 80 ° C.,
After heat-treating in an oven set at 90 ° C.,... 150 ° C. for 10 minutes under no tension, the shrinkage of the film is determined and expressed as a percentage of the value obtained by dividing by the original dimension. Measured in the same way for both perforated and unperforated parts.

(Thermal Shrinkage Initiation Temperature of the Film) Both ends of a film of a fixed size (4 mm × 10 mm) are fixed by chucking, and the temperature is raised (3.5 ° C./min) to start shrinkage of the film. The temperature was determined. (Used equipment: TMASS150C, manufactured by SII)

(Film melting point) Constant weight (4.0 m
g) was heated at a constant heating rate (10 ° C./min) to determine the melting point of the film. (Use equipment: SII
Company, DSC: 6100

Regarding the heat generation characteristic distribution on the thermal head at the time of plate making in the present invention, when attention is paid to one heating element, the temperature at the center of the heating element is the highest (EX300).
(° C. or more). In addition, when continuous heat generation is performed, a thermal overlap occurs between each heat generation element and a heat generation element to be punched next in a peripheral portion thereof.

Therefore, when a stencil printing plate using a single heat-sensitive film is perforated with a thermal head or the like to make a stencil, heat is applied to a surface other than the heating element (including a time lag in the master transport direction). , Heat shrinkage of the film occurs and plate making distortion occurs.

This thermal overlapping temperature rises to a certain temperature when the film is opened. In the present invention, it has been found that good plate making can be achieved by suppressing the rise (low temperature side) of the heat shrinkage of the film to a low level (→ 0%).

That is, the heat shrinkage onset temperature, the melting point of the film, and the amount of energy applied to the thermal head affect the heat shrinkage of the unopened portion of the film. When applied from the head, it was found that the thermal energy had a considerable effect on the thermal shrinkage of the unperforated portion of the heat-sensitive stencil printing paper, and a condition that did not cause thermal shrinkage at that temperature was derived. is there.

The physical properties of the film required for the perforated portion as the heat shrinkage characteristics of the film (the value of the heat shrinkage of the film required to open the hole with a heat source such as a thermal head)
In addition, the physical properties of the film required to prevent plate-making wrinkles (the same thermal shrinkage value as above) are preferably higher for the former (the film has been developed in the direction of higher sensitivity). ) The latter is preferably lower.

The present invention has solved the above problem without lowering the perforation sensitivity of the film. In particular, the present invention changes the shrinkage rate of the film on the low temperature side within the temperature range from the heat shrinkage initiation temperature to the melting point of the film. The one that is made is particularly effective.

By using such heat-sensitive stencil printing base paper, a combination with a support-less stencil, a porous resin film excellent in image quality, or a combination with a porous support (low basis weight) can be obtained. It is now possible to create heat-sensitive stencil base paper.

If the heat shrinkage exceeds 55%, unnecessarily large holes are formed during thermal drilling, which is not preferable. Also 5
%, The amount of energy required for opening increases. Further, the state of the holes after the opening is also an opening state with poor ink permeability, which is not preferable because the perforation sensitivity is insufficient.

By controlling the value of the heat shrinkage on the high temperature side in this way, it is possible to prevent the holes from being unnecessarily widened or unopened due to insufficient drilling sensitivity.

Further, the present inventors, by applying a porous resin film to the above-mentioned film, provide a heat-sensitive stencil sheet with better control of ink permeability, and obtain a printed matter of uniform image quality. I found something to be done.

Further, the present inventors have found that the strength of the heat-sensitive stencil printing base paper can be further increased by providing a reinforcing material to the heat-sensitive stencil printing base paper. By providing such a reinforcing material, generation of plate-making wrinkles is naturally eliminated, and transportability such as attachment of the base paper to the actual machine drum is remarkably improved.

The film of the present invention may be produced by a method of producing a general thermoplastic resin film formed by an extrusion method, a casting method, or the like, and may be a polyester, nylon, polyolefin, polystyrene, vinyl chloride, acrylic, or the like. Homopolymers or copolymers such as acid derivatives, ethylene-vinyl alcohols, and polycarbonates are preferred raw materials.

Of these, particularly preferred are polyester copolymers, and various polyesters in which different polycarboxylic acids and / or different polyols are present in the components. In addition, a copolymer nylon obtained by copolymerizing two or more homonylons is also particularly preferable for the nylon-based polymer.

The thermoplastic resin film may contain, if necessary, a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, an organic lubricant such as a pigment, a dye, a fatty acid ester, a wax, or a polysiloxane. An antifoaming agent or the like can be blended.

Further, lubricity can be imparted if necessary. There is no particular limitation on the method of imparting lubricity, but, for example, clay, mica, titanium oxide, calcium carbonate, kaolin, talc, inorganic particles such as wet or dry silica, acrylic acid, organic particles containing styrene and the like as constituents And the like, a method using internal particles, a method of applying a surfactant, and the like.

The thermoplastic resin film is stretched,
In particular, biaxial stretching is preferred. As a general stretching method, it is manufactured by longitudinal stretching with a heating roll and transverse stretching with a tenter or the like. The thickness of the original film is 0.5 to 20 μm, preferably 1.5 to 10 μm.
μm is better.

The original film may be provided with a heat-sealing preventing layer on the surface of the film in order to prevent heat-sealing to the heating element of the thermal head. Examples of the heat fusion inhibitor used for this purpose include fatty acid metal salts, phosphate ester type surfactants, fluid lubricants such as silicone oil, and fluorine compounds having a perfluoroalkyl group.

The coating amount of the heat-sealing preventing agent is 0.0
01 to 2.000 g / m ² , preferably 0.005 to 1.
000 g / m ² . In addition, in order to prevent transport failure due to static electricity, an original film having an antistatic agent applied to the film surface can be used.

Examples of the antistatic agent used for this purpose include general antistatic agents such as polyalkylene oxides, esters, amines, metal salts of organic sulfonic acids, carboxylate salts, quaternary ammonium salts, and alkyl phosphate esters. It can be used, and its coating amount is 0.001 to 2.0 g / m ² , preferably 0.01 to 0.5 g / m ² . The application method of the antistatic agent may be a usual method.

It is also possible to provide an antistatic effect by adding an antistatic agent to the film, and the antistatic agent added for this purpose includes metal salts of organic sulfonic acids, polyalkylene oxides, and the like. Quaternary ammonium salts and the like are preferred.

The thermal head used in the present invention comprises:
The heating elements are arranged in a horizontal line. As such a thermal head, any one can be used as long as an independent hole can be thermally formed in the original film surface.
In the case of the present invention, regarding the size of the heating element, the length in the main scanning direction is 15 to 75% of the pitch between the heating elements, preferably 15%.
It is preferable to use a thermal head in which the length in the sub-scanning direction is 15 to 75%, preferably 15 to 55% of the pitch between the heating elements.

A plate making film in which such a heating element is obtained by using a thermal head defined to a specific size is as follows:
Even if a perforated image that easily falls off from the perforated film during printing of a solid black image or a loop image such as a circle (）) in the perforated image exists, it is possible to give a printed image without any omission of those images. There are advantages. Further, the heating element density (the number of heating elements per unit length) of the thermal head is preferably 12 dots / inch or more.

In the present invention, the heat shrinkage of the heat-sensitive film is specified, and the amount of applied energy required for heat opening of the heat-sensitive stencil plate is 0.001 mJ / dot to 1.0.
The range of 00 mJ / dot is good, and the more preferable applied energy amount is 0.05 mJ / dot to 0.80 m.
It is in the range of J / dot. Further, the applied pulse width is preferably in the range of 0.001 to 10.0 msec.

The porous resin film in the present invention may have a structure having a large number of voids inside and on the surface of the film. It is desirable to use a continuous structure.

In the present invention, the average pore size of the porous resin film is generally 2 μm or more and 50 μm or less, preferably 5 μm or more and 30 μm or less. If the average pore size is less than 2 μm, the ink permeability is poor. Therefore, if a low-viscosity ink is used in order to obtain a sufficient amount of ink to pass through, a phenomenon occurs in which an image bleeds or the printing ink oozes out from the side of the printing drum or the rear end of the wound master during printing. . In addition, the porosity in the porous resin film is often low, and it is easy to hinder perforation by the thermal head. On the other hand, if the average pore diameter exceeds 50 μm, the effect of suppressing the ink by the porous resin film is reduced, and the ink between the printing drum and the film is excessively extruded during printing, causing problems such as back stains and bleeding. I do.

That is, if the average pore size is too small or too large, good print quality cannot be obtained. In particular, when the average pore diameter of the voids in the porous resin film is 20 μm or less, the thicker the porous resin film layer, the more difficult it is for the printing ink to pass through. Therefore, the amount of ink transferred to printing paper depends on the thickness of this layer. Can be controlled. If the thickness of the layer is not uniform, printing unevenness may occur. Therefore, it is desirable that the thickness be uniform.

The thickness of the porous resin film of the present invention is 2 μm or more and 100 μm or less, preferably 5 μm or more and 50 μm or less. If it is less than 5 μm, the porous resin film hardly remains behind the perforated portion after perforation by the thermal head,
The back transfer of the printed matter is apt to occur without controlling the ink transfer amount. In addition, the effect of the porous resin film for suppressing the amount of ink transferred is greater as the film is thicker, and the amount of ink transferred to paper during printing can be adjusted by the thickness of the porous resin film.

The density of the porous resin film is usually 0.01 g /
cm ³ or more and 1 g / cm ³ or less, preferably 0.1 g / c
m ³ or more and 0.7 g / cm ³ or less. Density is 0.01c
If it is less than m ³ , the strength of the film is insufficient, and the film itself is easily broken.

The adhesion amount of the porous resin film was 0.1 g / m ²
Not less than 35 g / m ² , preferably from 0.5 g / m ^{2 to} 25 g / m ²
g / m ^2, especially 1~11g / m ² is desirable. Adhesion amount of increase will degrade the image quality prevent passage of ink, 0.1 g / m ²
Below, it is difficult to control the amount of ink transfer, and conversely, 35 g
If it is more than / m ² , the passage of ink is hindered and the image is deteriorated.

Examples of the resin material constituting the porous resin film include polyvinyl acetate, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer and the like. Examples thereof include vinyl resins, polyamides such as polybutylene and nylon, polyphenylene oxide, (meth) acrylate, polycarbonate, polyurethane, cellulose derivatives such as acetylcellulose, acetylbutylcellulose and acetylpropylcellulose. Each resin may be used in combination of two or more.

In order to control the formation, strength, pore size, etc. of the porous resin film, it is desirable to add an additive such as a filler to the porous resin film as needed.
Here, the filler is a concept including pigments, powders, and fibrous substances. Among them, needle-like fillers are particularly preferable. Specific examples thereof include magnesium silicate, sepiolite, potassium titanate, wollastonite, zonotolite, mineral acicular fillers such as gypsum fiber, non-oxide acicular whiskers, oxide whiskers, and mixed oxides. Examples include artificial mineral needle-like fillers such as whiskers, and plate-like fillers such as mica, glass flake, and talc.

The pigments include not only inorganic but also organic pigments, or organic polymer particles such as polyvinyl acetate, polyvinyl chloride, and polymethyl acrylate, and zinc oxide, titanium dioxide, calcium carbonate, and silica. Matsumoto Microsphere, a microcapsule manufactured by Matsumoto Yushi Seiyaku Co., Ltd., can also be used effectively.

The amount of these additives is preferably 5% to 200% based on the resin. If it is less than 5%, the bending stiffness due to the addition of the additive does not increase. Conversely, if it is 200% or more, the adhesion to the film will be poor.

In the porous resin film of the present invention, an antistatic agent, a stick preventing agent,
Surfactants, preservatives, defoamers and the like can be used in combination.

Next, a method for forming a porous resin film will be described. The first method for forming a porous resin film is to apply a coating liquid obtained by dissolving and / or dispersing a resin in a mixed solvent of a good solvent and a poor solvent, and to form a porous film in a drying process. Things. At this time, the combination of the good solvent and the relatively low temperature of the poor solvent needs to be easily evaporated. When one good solvent and one poor solvent are used, respectively, the boiling point of the good solvent must be relatively lower than the boiling point of the poor solvent. The selection of the good solvent and the poor solvent is optional, but generally, when the boiling point difference is 15 to 40 ° C., a porous resin film having desired characteristics is easily formed. When the boiling point difference is less than 10 ° C., the difference in evaporation time between the two solvents is small, and the formed film is less likely to have a porous structure. If the boiling point of the poor solvent is too high, drying takes a long time and the productivity is poor, so the boiling point of the poor solvent is desirably 150 ° C. or lower.

The resin concentration in the coating solution varies depending on the material used, but is 5 to 30%. If it is less than 5%, the opening diameter becomes too large, and the thickness of the porous resin film tends to be uneven. Conversely, if it exceeds 30%, it is difficult to form a porous resin film, or even if it is formed, the pore size becomes small and it is difficult to obtain desired characteristics. The average pore size of the porous resin film is affected by the poor solvent in the atmosphere. In general, the higher the ratio to the good solvent, the larger the amount of coagulation and the larger the average pore size.

The ratio of the poor solvent to be added depends on the resin and the solvent, and must be appropriately determined by taking a test. Typically,
The pore size of the porous resin film increases as the amount of the poor solvent increases. If the amount of the poor solvent is too large, the resin is precipitated and the coating liquid becomes unstable.

The method for forming the second porous resin film is as follows.
As disclosed in Japanese Patent Application Laid-Open No. 11-235885, a fluid mainly composed of a W / O emulsion is applied on a thin layer and dried. This is a method in which holes are formed through which the ink passes, and the resin (which may contain an additive such as a filler or an emulsifier) in the solvent becomes a structure. In this method as well, additives such as the above-mentioned fillers can be added to the porous film as needed in order to adjust the formation, strength, pore size, stiffness and the like of the porous film. Among them, needle-like, plate-like, or fibrous fillers are particularly preferable.

HLB (Hydrophiric-Lyophiric Balanc) is relatively lipophilic for the formation of W / O emulsions.
e) Surfactants with 4 to 6 are effective, but H
When a surfactant having an LB of 8 to 20 is used, a more stable and uniform W / O emulsion is obtained. The use of a polymeric surfactant is also one of the methods for obtaining a more stable and uniform emulsion. Addition of a thickener such as polyvinyl alcohol or polyacrylic acid to the aqueous system is effective for stabilizing the emulsion. The method for forming the porous resin film of the present invention is not limited to the method exemplified above.

The method of applying the coating liquid for forming a porous resin film of the present invention to a thermoplastic resin film includes a blade, a transfer roll, a wire bar, a reverse roll, and the like.
Conventionally commonly used coating methods such as gravure and die can be used and are not particularly limited.

Examples of the porous fiber membrane (reinforcing material) used in the present invention include porous thin paper (Norigucho), porous synthetic fiber paper, various woven fabrics, and nonwoven fabrics.

As the porous thin paper, natural fibers such as kozo, honey or manila hemp, flax, etc., or those obtained by mixing chemical structures such as rayon, vinylon, polyester alone or in an appropriate ratio are used. In particular, basis weight 1-12
A porous thin paper having the characteristics of gram / m ² , density of 0.1 to 0.8 g / ml, and air permeability of 0.5 to 12 seconds / 96 sheets (all measured by the JIS method) is preferred.

The porous fiber membrane (reinforcing material) in the present invention
The method of bonding with a thermosensitive stencil sheet having a thermoplastic resin film and a porous resin film provided thereon is performed by multi-roll coating, reverse roll coating,
An appropriate amount of an adhesive is applied to the surface of the porous support by means such as gravure coating, offset gravure coating, kiss coating, and rotary screen coating, and then pressed against a thermoplastic resin film to dry or cure the adhesive.

Examples of the adhesive include a urethane resin, a reactive prepolymer of a diisocyanate and a polyether diol, a mixed adhesive of an active hydrogen-containing resin and a polyisocyanate, an ultraviolet ray and an electron beam curing adhesive, and the like.

The viscosity of the adhesive at the time of application to the porous support is preferably from 200 cps to 3000 cps, more preferably from 300 cps to 1500 cps.
It is as follows. If the viscosity is lower than 200 cps, it is difficult to obtain sufficient adhesiveness, partial lamination failure occurs, image reproducibility is deteriorated, or the roll of the laminator is stained due to excessive penetration into the porous support. is there.
Conversely, if the viscosity is higher than 3000 cps, the adhesive will block the opening of the porous support, causing white spots on the printed matter,
Even with a porous support, the surface strength becomes insufficient, and for example, inconvenience due to detachment of fibers from the tissue occurs.
0.03~5.0g / m ² as a coating amount of the adhesive, preferably 0.05 to 1.5 g / m ^2, more preferably at 0.1 to 1.0 g / m ^2.

[0064]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Evaluation Method] A heat-sensitive stencil sheet was heat-plated by a plate-making apparatus in which the plate-making section of Ricoh VT-3820 was remodeled, and this was observed with a microscope, and a large number of holes perforated independently as black solid sections were formed. The distance between the center points was measured for 20 dots, and from this result, the expansion / contraction ratio of the perforated image forming the solid black portion was obtained by the following equation. (Stretch ratio)

## EQU5 ## Expansion / contraction ratio (%) = (l−L) / L × 100 L: Standard dimensional value, between the center point of the left end dot and the center point of the right end dot for 20 dots of the heating elements arranged in a row. Distance l: The measured value, the center point of the upper end (left end) hole and the center point of the lower end (right end) hole of 20 independent holes formed in a vertical (horizontal) line formed on the plate making film by the 20 dots of the heating element. Distance between.

(Thermal shrinkage) Constant size (10 cm × 1)
0 cm) at each temperature (... 60 ° C, 70
, 80 ° C., 90 ° C .... 150 ° C.), and then heat-treated in an oven without tension for 10 minutes. Then, the shrinkage of the film was determined and expressed as a percentage ratio of a value obtained by dividing by the original dimension. Measured in the same way for both perforated and unperforated parts.

(Thermal Shrinkage Onset Temperature of Film) A fixed size (4 mm × 10 mm) film is fixed at both ends by chucking, and a constant temperature rise (3.5 ° C./min) is performed. I asked. (Used equipment: TMASS150C, manufactured by SII)

(Film melting point) Constant weight (4.0 m
g) was heated at a constant heating rate (10 ° C./min) to determine the melting point of the film. (Use equipment: SII
(DSC: 6100)

Further, the plate-making film obtained by thermal plate-making is wound around a printing drum of a heat-sensitive stencil printing machine Preport VT-2500 manufactured by Ricoh Co., Ltd., and printing is performed at a printing speed of 90 sheets / min. It was observed whether wrinkles occurred in the solid portion. Further, the prepared heat-sensitive stencil sheet was observed for the occurrence of sagging wrinkles. Further, for the printed matter obtained by the above method, the optical density of the solid black portion was measured with a Macbeth RD-914 densitometer,
The sharpness and the like of the printed matter printed by the thermoplate made in the present invention were examined.

Example 1 As a heat-sensitive stencil sheet, the value of the heat shrinkage of the unperforated portion at 90 ° C. in the main scanning direction was 4%, and the value in the sub-scanning direction was 90%.
The value of the heat shrinkage of the unperforated portion at 3 ° C. is 3%, 150 ° C.
The thermal contraction value of the perforated portion in the main scanning direction is 38%, 15%.
The value of the heat shrinkage of the perforated portion in the sub scanning direction at 0 ° C. is 33%,
Melting point 160 ° C, heat shrink start temperature 60 ° C, thickness 3.0μm
Polyethylene terephthalate (PET) film, 0.01 g / m ² of silicone oil SF-8422 manufactured by Toray Dow Corning Co., Ltd. as an anti-fusing agent, and Elegan 264A (Quarter grade) manufactured by NOF Corporation as an antistatic agent. An ammonium salt-based antistatic agent) was applied in an amount of 0.01 g / m ² . The heating element length in the main scanning direction is 31 μm and the heating element pitch is 62.5 μm, and the heating element length and the heating element pitch in the sub-scanning direction are 34.2 μm and 6 μm, respectively.
The above-described heat-sensitive stencil sheet was prepared by using a thin-film thermal head of 16 μm / mm (2.5 μm) as a heat source and applying energy of 0.036 mj / dot (plate making speed: 2.25 msec / line, application pulse width: 400 μsec). Then, all dots were punched in the main scanning direction 200 mm × sub-scanning direction 300 mm.

When the heat-sensitive stencil sheet prepared as described above was observed with a microscope, the perforated portion was elongated by + 0.05% in the sub-scanning direction and contracted by -0.05% in the main scanning direction by the hot plate making. Was. This means that the dimensional reproducibility of the image is extremely high. Therefore, in this plate making sample, no plate making wrinkles were generated, and the setting to the printing drum was performed satisfactorily. In addition, the optical density of the solid black portion of the printed matter printed with this plate-making product was 1.18, and the printed image was clear. The printed matter had no fine lines due to wrinkles, and the quality of the printed matter was good.

Example 2 As a heat-sensitive stencil sheet, the value of the heat shrinkage ratio of the unperforated portion at 90 ° C. in the main scanning direction was 5%, and the value in the sub-scanning direction was 90%.
The value of the heat shrinkage of the unperforated portion at 4 ° C is 4%, 150 ° C
The thermal contraction value of the perforated portion in the main scanning direction is 35% and 150%.
A polyethylene terephthalate (PET) film having a heat shrinkage rate of 30%, a melting point of 160 ° C., a heat shrinkage initiation temperature of 60 ° C., and a thickness of 3.0 μm, and a thickness of 25 μm was used. A porous resin film was applied. Further, 0.01 g / m ² of silicone oil SF-8422 manufactured by Toray Dow Corning Co., Ltd. was used as a thermal fusion preventing agent, and Elegan 264A (a quaternary ammonium salt type antistatic agent) manufactured by NOF Corporation was used as an antistatic agent. 0.01 g / m ^{2 was} applied.

A sample was prepared in the same manner as in Example 1 except that the porous resin film was provided in this manner. As in Example 1, the heating element length in the main scanning direction was 31 μm and the distance between the heating elements was 31 μm. The pitch is 62.5 μm, and the heating element length in the sub-scanning direction and the pitch between the heating elements are 34.2 μm, respectively.
and a thin film type thermal head of 16 dots / mm of 62.5 μm as a heat source, and applied energy of 0.036
mJ / dot (plate making speed: 2.25 msec / line,
With the applied pulse width: 400 μsec), all the dots were perforated in the above-mentioned printing original plate in a main scanning direction of 200 mm × sub scanning direction of 300 mm.

When the heat-sensitive stencil sheet prepared as described above was observed with a microscope, the perforated portion was expanded by + 0.03% in the sub-scanning direction and contracted by -0.03% in the main scanning direction due to the hot plate making. Was. This means that the dimensional reproducibility of the image is extremely high. Therefore, in this plate making sample, there was no generation of plate making wrinkles, and the setting to the printing drum was performed satisfactorily. The optical density of the solid black portion of the printed matter printed with this plate-making product was 1.15.
And the printed image was clear. The printed matter had no fine lines due to wrinkles, and the quality of the printed matter was good.

Example 3 As a heat-sensitive stencil sheet, the value of the heat shrinkage of the unperforated portion at 90 ° C. in the main scanning direction was 5%, and the value in the sub-scanning direction was 90%.
The value of the heat shrinkage of the unperforated portion at 4 ° C is 4%, 150 ° C
The thermal contraction value of the perforated portion in the main scanning direction is 35% and 150%.
A polyethylene terephthalate (PET) film having a heat shrinkage rate of 32%, a melting point of 160 ° C., a heat shrinkage starting temperature of 60 ° C., and a thickness of 3.0 μm in the sub-scanning direction at 32 ° C. was used. A porous resin film was applied. Thereafter, a porous support mainly composed of a synthetic resin having a basis weight of 7.5 g / m ² was bonded using an adhesive. Further, 0.01 g / m ² of silicone oil SF-8422 manufactured by Toray Dow Corning Co., Ltd. was used as a thermal fusion preventing agent, and Elegan 264A (a quaternary ammonium salt type antistatic agent) manufactured by NOF Corporation was used as an antistatic agent. 0.01 g / m ^{2 was} applied.

A sample was prepared in the same manner as in Example 1 except that the porous resin film and the reinforcing material (porous support) were provided in this manner. The heating element length is 31 μm and the pitch between the heating elements is 6
A 16 dot / mm thin-film thermal head having a heating element length of 2.5 μm, a heating element length in the sub-scanning direction and a pitch between the heating elements of 34.2 μm and 62.5 μm, respectively, was used as a heat source, and the applied energy was 0.036 mJ / dot. (Plate making speed: 2.25 msec / line, applied pulse width: 400
μsec) in the main scanning direction 200 m
All dots were perforated in the mx 300 mm sub-scanning direction.

When the heat-sensitive stencil sheet prepared as described above was observed with a microscope, the perforated portion was elongated by + 0.02% in the sub-scanning direction and -0.02% in the main scanning direction by the hot plate making. Had contracted. This means that the dimensional reproducibility of the image is extremely high. Therefore, in this plate making sample, no plate making wrinkles were generated, and the setting to the print drum was performed favorably and easily. In addition, the optical density of the solid black portion of the printed matter printed with this plate-making product was 1.00, and the printed image was clear. The printed matter had no fine lines due to wrinkles, and the quality of the printed matter was good.

Example 4 As a heat-sensitive stencil sheet, the value of the heat shrinkage of the unperforated portion at 80 ° C. in the main scanning direction was 4.5%, and the value of the heat shrinkage of the unperforated portion at 80 ° C. in the sub-scanning direction was The value is 1.2%,
The thermal contraction value of the perforated portion in the main scanning direction at 150 ° C. is 45
A polyethylene terephthalate (PET) film having a heat shrinkage rate of 42%, a melting point of 160 ° C., a heat shrinkage initiation temperature of 60 ° C., and a thickness of 3.0 μm, in the sub-scanning direction at 150 ° C. A 10 μm porous resin film was applied. Thereafter, a porous support mainly composed of a synthetic resin having a basis weight of 7.5 g / m ² was bonded using an adhesive. Further, 0.01 g / m ² of silicone oil SF-8422 manufactured by Toray Dow Corning Co., Ltd. was used as a thermal fusion preventing agent, and Elegan 264A (a quaternary ammonium salt type antistatic agent) manufactured by NOF Corporation was used as an antistatic agent. 0.01 g / m ^{2 was} applied.

A sample was prepared in the same manner as in Example 1 except that the porous resin film and the reinforcing material (porous support) were provided in this manner. The heating element length is 31 μm and the pitch between the heating elements is 6
A 16 dot / mm thin-film thermal head having a heating element length of 2.5 μm, a heating element length in the sub-scanning direction and a pitch between the heating elements of 34.2 μm and 62.5 μm, respectively, was used as a heat source, and the applied energy was 0.036 mJ / dot. (Plate making speed: 2.25 msec / line, applied pulse width: 400
μsec) in the main scanning direction 200 m
All dots were perforated in the mx 300 mm sub-scanning direction.

When the heat-sensitive stencil sheet prepared as described above was observed with a microscope, the perforated portion was elongated by + 0.02% in the sub-scanning direction and contracted by -0.02% in the main scanning direction by the hot plate making. Was. This means that the dimensional reproducibility of the image is extremely high. Therefore, in this plate making sample, no plate making wrinkles were generated, and the setting to the printing drum was performed well and easily. In addition, the optical density of the solid black portion of the printed matter printed with this plate-making product was 1.00, and the printed image was clear. The printed matter had no fine lines due to wrinkles, and the quality of the printed matter was good.

Comparative Example 1 The thermal shrinkage of the unperforated portion in the main scanning direction at 90 ° C. of the heat-sensitive film was 20%, and the thermal shrinkage of the unperforated portion in the sub-scanning direction was 2%.
A sample was prepared in the same manner as in Example 1 except that the film was 0%. Thereafter, the sample was subjected to thermal perforation in exactly the same manner as in Example 1.

Observation of the heat-sensitive stencil sheet for heat stencil printing thus made under a microscope revealed that the perforated portion was elongated by 2.30% in the sub-scanning direction due to the heat stencil printing. Sex was bad. Further, when the perforated film was visually observed, generation of sagging wrinkles was observed. When printing was performed using this sample, the image was printed clearly, but fine lines were generated on the image due to wrinkles on the film, and it could not be said that the printed matter faithfully reflected the original image. Did not.

[0083]

As described above, it is clear from the detailed and concrete description that the use of the heat-sensitive stencil sheet of the present invention eliminates the occurrence of plate-making wrinkles and provides a high-quality heat-sensitive stencil having excellent dimensional accuracy. Printing base paper can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumiaki Arai 1-3-6 Nakamagome, Ota-ku Tokyo -1 F-term in Tohoku Ricoh Co., Ltd. (Reference) 2H084 AA14 AE05 BB04 CC09 2H114 AB23 AB25 BA06 DA43 DA48 DA49 DA50 DA51 DA52 DA56 DA57 DA60 DA61 EA02 EA08 FA06 FA09

Claims (5)

[Claims] 1. A heat-sensitive stencil sheet having a thermoplastic resin film, wherein the heat-sensitive stencil sheet has a heat source such as a thermal head.
When perforation is performed with an energy of 0.001 mJ / dot to 1.000 mJ / dot and all dots are perforated in the thermosensitive stencil sheet, expansion and contraction of the thermosensitive stencil sheet in the sub-scanning direction and the main scanning direction after perforation. Base paper for heat-sensitive stencil printing, characterized in that the rate is within ± 1.00%. 2. The heat-sensitive stencil printing paper according to claim 1, wherein the value of the heat shrinkage of the thermoplastic resin film in the unperforated portion is 15% or less within a temperature range of T1 described below. ## EQU1 ## Tc <T1 <Tm1 _{/ 2} Tc: Thermal shrinkage onset temperature of the film Tmp: Melting point of the film Tm1 _{/ 2} : Intermediate (1/2) temperature between Tc and Tmp Thermal shrinkage: predetermined temperature Shrinkage after 10 minutes 3. The value of the thermal shrinkage of the thermoplastic resin film in the perforated portion is 5% or more within the temperature range of T2 described below.
The heat-sensitive stencil printing paper according to claim 1, wherein the content is 5% or less. ## EQU2 ## Tm _1/2 <T2 <Tmp Tc: Thermal shrinkage starting temperature of the film Tmp: Melting point of the film Tm1 _{/ 2} : Temperature intermediate (1/2) between Tc and Tmp Thermal shrinkage: predetermined temperature Shrinkage after 10 minutes 4. The heat-sensitive stencil printing paper according to claim 2, wherein a porous resin film is provided on the thermoplastic resin film. 5. The heat-sensitive stencil printing paper according to claim 4, wherein a reinforcing material such as a porous fiber membrane is provided on the heat-sensitive stencil printing paper.