JP3041391B2 - Heat-sensitive stencil making method - Google Patents

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 printing method, and more particularly, to a heat sensitive stencil sheet made by laminating a thermoplastic resin film and a porous support, or a heat sensitive stencil sheet consisting essentially of a thermoplastic resin film. The present invention relates to a heat-sensitive stencil making method using base paper.

[0002]

2. Description of the Related Art Conventionally, a stencil printing method has been widely used as a simple printing method. In this method, a thermoplastic resin film laminated on a suitable ink-permeable support surface is used as a heat-sensitive stencil sheet. A thermoplastic resin film is heated and melted by a thermal head or the like to form image-like perforations, and printing is performed on a printing material such as paper through printing ink from the ink-permeable support side. Further, using a heat-sensitive stencil sheet consisting essentially of a thermoplastic resin film (hereinafter sometimes referred to as a support-less stencil), the thermoplastic resin film is heated and melted by a thermal head to form image-like perforations. The printing is performed on a printing material such as paper through a printing ink with a single plastic resin film.

[0003]

Problems to be Solved by the Invention As the thermal head used in the above-mentioned thermal stencil making method, a thermal head for thermal color recording or thermal transfer recording has been diverted. These thermal heads for thermal recording are designed so that each pixel, which is the recorded image, is continuous.If this thermal head is used as it is for thermal stencil printing, the perforated image will be continuous, and as a result The transfer increased and the printing durability was poor. On the other hand, by adjusting the energy applied to the thermal head, the diameter of the perforated image can be changed. That is, when the applied energy is increased, the diameter of the perforation increases, and conversely, when the energy is decreased, the diameter of the perforation decreases. By doing so, there is a method for ensuring the independence of the perforated image. However, the optimum applied energy is the energy under the condition where the variation of the perforation of the perforated image is the smallest. This condition is generally also the maximum applied energy within a range that does not significantly reduce the durability of the thermal head. An increase is not preferable in terms of the durability of the thermal head. Further, as a new problem of the heat-sensitive stencil sheet without the support, there is an occurrence of an abnormal image (particularly, a wrinkle shape) due to shrinkage of the plate due to heat shrinkage of a non-image portion.

Japanese Patent Application Laid-Open No. 63-191654 discloses a heat-sensitive stencil sheet having a support, in order to solve the above-mentioned drawbacks, the thickness of the heat-generating element protective film alone is set to 0.5 to 3.5 μm.
Means have been proposed. However, when the thickness of the protective film is made extremely thin as described above, the number of pinholes in the protective film increases, and when the humidity is high, the antistatic agent penetrates through the pinholes, so that the electrode is easily corroded, However, even if it was not high, the wear resistance was insufficient. In addition, even if the thickness of the protective film is 0.5 μm, the perforated image may be easily continuous depending on the value between the heating elements. Abnormal images such as wrinkles due to certain plate shrinkage are likely to occur. Conversely, even when the thickness of the protective film is 3.5 μm, the perforated image may be too far depending on the value of the interval between the heating elements. Because of the small amount, the continuity of the printed image is lost.

Japanese Patent Application Laid-Open No. 2-67133 proposes a means for making the sub-scanning length of each heating element of a thermal head shorter than the dot pitch in the main scanning direction. However, in this case, the target master was a heat-sensitive stencil sheet having a support, which was not sufficient.
In particular, when a stencil sheet without a support is made, wrinkles due to plate shrinkage may occur. The degree of the wrinkles increases as the film thickness of the support-less stencil sheet increases. Further, even with a general thermosensitive stencil sheet, if the dot pitch in the main scanning direction is different from the dot pitch in the sub-scanning direction, continuous perforation may occur, or the support-less sheet may be used for the same reason as described above. In some cases, the perforated images were too far apart on the heat-sensitive stencil sheet.

From the above, it is an object of the present invention to provide a heat-sensitive stencil plate making method which is excellent in printing durability and has little set-off, and which is a new problem particularly in a support-less heat-sensitive stencil sheet and in which an abnormal image due to plate shrinkage does not occur. Is to get.

[0007]

An object of the present invention is to provide a heat-sensitive stencil sheet obtained by laminating a thermoplastic resin film and a porous support or a heat-sensitive stencil sheet consisting essentially of only a thermoplastic resin film by a thermal head. In the heat-sensitive stencil printing method for forming a perforated image on the film by applying thermal energy, the distance d (μm) between the heating elements of the thermal head and the thickness T (μm) of the heating element protective film are represented by the following formula (1). Is satisfied, and the heating interval D (μm) of the heating element of the thermal head and the thickness T (μm) of the heating element protective film satisfy the following equation (2). 5 ≦ d / T (1) 4.5 ≦ D / T (2) Here, the distance d (μm) between the heating elements of the thermal head is defined as the distance Pm (μm) between the centers of the heating elements in the main scanning direction. The length Lm (μm) of the heating element in the main scanning direction is reduced (d = Pm−Lm, see FIG. 1A). The heating interval D (μm) in the sub-scanning direction of the heating element of the thermal head is
Feed amount P per dot in the sub-scanning direction during plate making
This is obtained by subtracting the length Ls (μm) of the heating element in the sub-scanning direction from s (μm) (D = Ps−Ls, see FIG. 1B).

[0008] Further, the object of the present invention is to form a perforated image on a heat-sensitive stencil sheet consisting essentially of only a thermoplastic resin film by applying thermal energy to the film using a thermal head. The distance d (μm) and the thickness T (μm) of the heating element protection film satisfy the following expression (3), and the heating interval D (μm) of the heating element of the thermal head in the sub-scanning direction and the protection of the heating element. This is achieved when the thickness T (μm) of the film satisfies the condition of the following equation (4). 5 ≦ d / T ≦ 10 (3) 4.5 ≦ D / T ≦ 9 (4)

According to the present invention, since the perforated images are independent, there is little set-off in the printed matter, the printing durability of the original plate is excellent, and the occurrence of an abnormal image on the printed matter due to plate shrinkage. Plate making without any material becomes possible. In the case of a heat-sensitive stencil sheet without a support, since there is no support, all perforations formed by the heat-generating element itself become ink transmission areas, so that image density variation among pixels can be reduced. The independence of the perforated image is because the distance d (μm) between the heating elements and the heating interval D (μm) in the sub-scanning direction of the heating elements are sufficiently large compared to the thickness T (μm) of the protective film. Since the heat from the stencil sheet is transmitted to the heat-sensitive stencil sheet without greatly overlapping with the adjacent heating element, it can be secured. That is, the independence of the perforated image can be ensured by satisfying the following expressions (1) and (2) in the present invention. 5 ≦ d / T (1) 4.5 ≦ D / T (2) When the above expressions (1) and (2) are satisfied, not only the independence of the perforated image is improved but also the plate shrinkage does not occur. If the thickness of the protective film exceeds 7.0 μm and does not satisfy the above expressions (1) and (2), not only the independence of the perforated image is deteriorated, but also the thermal response of the thermal head is deteriorated. (Because the heat capacity of the protective film becomes high), the line speed of the plate making cannot be increased, and the plate shrinkage becomes particularly bad. When the thickness of the protective film is less than 3.5 μm, it is difficult to obtain a thermal head having sufficient durability. Also, the distance between the heating elements of the thermal head and the heating interval of the heating elements in the sub-scanning direction are 1
When the above formulas (1) and (2) are not satisfied without securing 7.5 μm, even when the independence of the perforated image can be ensured, it is difficult to sufficiently secure the non-perforated portion in the solid printing portion. In particular, the printing durability is not ensured.

In particular, in the case of a heat-sensitive stencil sheet without a support, in addition to the above-mentioned effects, the interval between perforated images becomes appropriate. 5 ≦ d / T ≦ 10 (3) 4.5 ≦ D / T ≦ 9 (4) In other words, when the expressions (3) and (4) are satisfied, the transfer amount of the ink depends on the characteristics of the support-less thermosensitive stencil sheet. At least, the continuity (solid uniformity) of the printed image is particularly improved.

Here, the difference between the ranges of the expressions (1) and (2) and the expressions (3) and (4) is due to the characteristics of the thermal head. Since the heating elements do not exist side by side, when the perforations adjacent to each other in the sub-scanning direction are obtained, heat generation of the thermal head for the perforations does not occur at the same time. Therefore, the distribution of heat generation for obtaining perforations is different from that in the case of adjacent holes in the main scanning direction. As a result, the ranges of the two expressions are different.

The thermal head used in the present invention has the same structure as a thin film type that can be used in a thermal printer. As shown in FIG. 2, a heat resistance layer 7 made of glass is formed on an insulating substrate 6, and Ni is formed on the upper surface of the heat resistance layer 7 by a vacuum deposition method or the like.
An electrode layer 9 made of a metal material such as Cr or Ta is formed by a vacuum deposition or the like via a heating resistor layer 8, and
In the heating portion, the oxidation resistant layer 10 is formed on the heating resistor layer 8.
Are directly joined, and the heat generating portion 12 is formed in a concave shape. Here, as the thin film type thermal head, a full glaze type or a partial glaze type (not shown) in FIG. 2 is used.
However, in this case, the same expression holds for both types.

As the thermoplastic resin film, an extrusion method,
Any general thermoplastic resin film formed by a casting method or the like may be used, and polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene α, β-
Polyesters such as bis (2-chlorophenoxy) ethane-4,4-dicarboxylate and polycarbonate;
Polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polybutadiene, polystyrene, and polymethylpentene; polyamides such as polyhexamethylene adipate (nylon 66); polyε-caprolactam (nylon 6); nylon 610; Halogenated polymer systems such as vinylidene chloride, polyvinylidene fluoride, and polyvinyl fluoride; vinyl polymer systems such as polyacrylonitrile and polyvinyl alcohol; polyacetal, polyether sulfone, polyether ketone, polyphenylene ether, polysulfone, polyphenylene sulfide, and copolymers thereof Coalescence and mixtures are mentioned. Preferably, a film having a high perforation sensitivity is effective, and for this purpose, a film in which the thermoplastic resin in the state of constituting the film ranges from a substantially amorphous level to a crystallinity of 15%. Good. More preferably, the film is at a substantially amorphous level. Here, the film having a substantially amorphous level is as follows.
There are cases where the raw material has almost no melting point by the DSC method, and cases where the crystallization is suppressed by a processing method (a quenching method or the like). If the degree of crystallinity is high, the energy from the thermal head is consumed for energy for melting the crystal, resulting in poor perforation. The crystallinity is determined by the X-ray method, but may be determined by increasing the area of the melting energy by the DSC method.

[0014] The film is more preferably based on a copolyester and the film is of a substantially amorphous level. Most preferably, the copolymer polyester as a raw material is substantially amorphous. Here, the substantially amorphous polyester is different from a so-called high-crystalline polyethylene terephthalate-based resin whose crystalline melting point (according to the DSC method) is usually 245 to 260 ° C. The crystallinity measured by using one sample or a blend of two or more polymers as a raw material in an equilibrium state by sufficiently annealing and fixing the crystallinity by an X-ray method and using this sample as a standard Is 10% or less, preferably 5% or less, and more preferably, almost no melting point is observed even by the DSC method. By using such a low crystalline type thermoplastic film, even if the energy applied to the thermal head is very small, the energy loss as the crystal melting energy is reduced, and sufficient thermal aperture can be achieved.

The thickness of the thermoplastic resin film used in the present invention is preferably 0.5 μm to 30 μm, more preferably 0.7 μm to 20 μm. If the thickness is too thin, even if the perforations are sufficiently independent, the mechanical strength is low, so the printing durability is particularly poor. Conversely, if the thickness is too thick, not only the perforations are difficult to obtain but also platemaking wrinkles are liable to occur. . The melting start temperature is 50 ° C to 300 ° C, preferably 70 ° C to 2 ° C.
90 ° C. If the melting start temperature is too low, not only the production of the film becomes difficult, but also the storage stability becomes poor when the heat-sensitive stencil paper itself is used. On the other hand, if it is too high, the energy given to the heat-sensitive stencil base paper from the thermal head required for perforation increases, and perforation is difficult to obtain.

The porous support may be made of natural fibers such as kozo, honey or manila hemp, semi-synthetic fibers such as rayon, synthetic fibers such as polyester, vinylon, nylon and polypropylene, and these may be used alone or in combination of two or more. And the weight is 8 to 15 g / m ² . Further, those obtained by adding an antistatic agent or the like to these porous supports may be used. Further, a porous resin film that can penetrate the ink may be used as the support.

As the adhesive for bonding the porous support and the thermoplastic resin film, acrylic resin, vinyl acetate resin, vinyl acetate resin to which rosin resin is added,
Methoxylated polyamide resin, vinyl chloride copolymer, chlorinated polypropylene resin, urethane adhesive which is a reaction prepolymer of diisocyanate and polyetherdiol, mixed adhesive of active hydrogen-containing resin and polyisocyanate, and ultraviolet curing And an electron beam curing adhesive.

When the thermal head is used as a perforating means, a heat fusion preventing treatment can be applied to the side of the thermoplastic resin film which comes into contact with the thermal head. Examples thereof include a method of uniformly applying a fluid lubricant such as a fatty acid metal salt, a phosphate ester type surfactant, and silicone oil, and a thermal fusion inhibitor such as a fluorine compound having a perfluoroalkyl group. The coating amount is 0.001 to ² g / m ² , preferably 0.005 to 1 g / m ² . If the coating amount is small, the effect of preventing heat fusion is not obtained, and if it is too large, the piercing property is deteriorated.

As a method for imparting an antistatic effect to the thermoplastic resin film, there is a method in which an antistatic agent is uniformly applied to the thermoplastic resin film, or a method in which the antistatic agent is contained in the thermoplastic resin film.

In the method of coating, as the antistatic agent, a metal salt of organic sulfonic acid or polylene oxide, ester, amine, polyethoxy derivative, carboxylate,
Examples include common antistatic agents such as amine guanidine salts, quaternary ammonium salts, and alkyl phosphates.

The coating amount of the antistatic agent is 0.001 to 2.
0 g / m ² preferably from 0.01 to 0.5 g / m ^2.
If the coating amount is too small, it is difficult to obtain a sufficient antistatic effect, especially in an environment with low humidity. Conversely, if the coating amount is too large, not only does the perforation property deteriorate, but also the effect of the anti-fusing agent is impaired.

In the method in which an antistatic agent is contained in a thermoplastic resin film, examples of the antistatic agent include metal salts of organic sulfonic acids, porylene oxide, and one or a mixture of two or more of quaternary ammonium salts.

The metal organic sulfonic acid salt has the formula RSO ₃ X
Wherein R is an aliphatic group, an alicyclic group, or an aromatic group, and X is a metal such as Na, K, and Li. ,
Examples thereof include alkyl benzene sulfonic acid metal salts. Examples of the alkyl include octyl, decyl, dodecyl (lauryl), tetradecyl (myristyl), hexadecyl, octadecyl (stearyl) and the like.
Further specific compounds include sodium lauryl sulfonate, potassium lauryl sulfonate, lithium lauryl sulfonate, sodium stearyl sulfonate, potassium stearyl sulfonate, lithium stearyl sulfonate, sodium dodecylbenzene sulfonate, potassium dodecylbenzene sulfonate, Examples thereof include lithium dodecylbenzenesulfonate. On the other hand, the content of the organic sulfonic acid metal salt in the thermoplastic resin film is 0.1%.
It is 1 to 2% by weight, preferably 0.2 to 1.5% by weight. When the amount of the organic sulfonic acid metal salt is less than 0.1% by weight, the antistatic effect is small. On the other hand, when the amount exceeds 2% by weight, the film surface is undesirably roughened. In addition, the content of the organic sulfonic acid metal salt in the thermoplastic resin film is 0.1 to 2% by weight, preferably 0.2 to 1.5% by weight. 0.1% by weight of organic metal sulfonate
When the amount is less than the above, the antistatic effect is small. On the other hand, when the amount exceeds 2% by weight, the surface of the thermoporous sheet is roughened, which is not preferable.

As the porylene oxide contained in the thermoplastic resin film, polyethylene oxide,
Examples thereof include polypropylene oxide, polyethylene-propylene oxide copolymer, and polytetramethylene oxide, and have a molecular weight of 400 to 500,000, more preferably 1 to 500,000.
000-50,000. The content of the polyalkylene oxide is 0.1 to 5% by weight based on the thermoplastic resin film,
Preferably it is 0.2 to 4% by weight. When the amount of the porylene oxide is less than 0.1% by weight, the antistatic property decreases, while when it exceeds 5% by weight, the mechanical properties of the film deteriorate, which is not preferable.

The conductive agent to be contained in the thermoplastic resin film is represented by the formula [(RN (CH ₃ ) ₂ -R ′] X (where R is an alkyl group having 12 to 18 carbon atoms, and R ′ is X represents CI or an alkyl group or methyl group having 12 to 18 carbon atoms;
Alternatively, one or a mixture of two or more quaternary ammonium salts represented by Br) is used. The content of the ammonium salt is 1 to 50% by weight, more preferably 2 to 30% by weight, based on the thermoplastic resin film.

Now, the present invention will be described in further detail with reference to Examples. However, it should be understood that the present invention is by no means restricted by such specific Examples.

[0027]

【Example】

Example 1 A film mainly composed of a copolymerized polyester as a thermoplastic resin film was substantially amorphous (crystallinity of 1.0).
%) Thickness 1.8 μm, using a melting temperature of 160 ℃,
11 consisting of 15% polyester fiber and 85% Manila hemp
Lamination was carried out with a porous support of g / m ² . A phosphate ester-based surfactant (Gaffa RL210, manufactured by Toho Chemical Industry Co., Ltd., mp. 54 ° C.) is applied as a heat-fusion preventing layer on the side in contact with the thermal head so as to have a concentration of 0.1 g / m ² . A heat-sensitive stencil sheet having a porous support was obtained.
This heat-sensitive stencil sheet is coated with a 16-dot / mm thin-film thermal head (heating element main scanning length Lm: 42 μm, sub-scanning length
Ls: 32 μm, heating element protective layer thickness T: 4.0 μm,
Using a feed amount in the sub-scanning direction during plate making (Ps: 62.5 μm), applied energy was applied to the thermal head so that the probability of obtaining perforations was 90% or more, and plate making including a solid black image portion was performed. This plate-formed thermoplastic resin film was set on a pre-port SS955 manufactured by Ricoh Co., Ltd., and printing was performed. As a result, an image having excellent solid uniformity and little set-off was obtained. There were no wrinkles on the image due to plate shrinkage. The printing durability was also at a level without any problem. At this time, each d / T and D / T are d / T = 5.1 and D / T =
7.6.

Example 2 As a thermoplastic resin film, a film mainly composed of a copolymerized polyester was substantially amorphous (crystallinity of 1.0).
%) Thickness 1.8 μm, using a melting temperature of 160 ℃,
A phosphate ester-based surfactant (Gaffa RL210, manufactured by Toho Chemical Industry Co., Ltd., mp. 54 ° C.) as a heat-fusion preventing layer on the side in contact with the thermal head is 0.1 g / m ^2.
It was applied so that This thermoplastic resin film is
6-dot / mm thin-film thermal head (heating element main scanning length Lm: 45 μm, sub-scanning length Ls: 45 μm Heating element protective layer thickness T: 3.5 μm, feed amount in the sub-scanning direction during plate making Ps: 62.5 μm ) Was applied to the thermal head so that the probability of perforation being obtained was 100%, and plate making including a black solid image portion was performed. The plate-made thermoplastic resin film was set on a pre-port SS955 manufactured by Ricoh Co., Ltd., and printing was performed. As a result, an image having excellent solid uniformity and little set-off was obtained. There were no wrinkles on the image due to plate shrinkage. The printing durability was also at a level without any problem. At this time, d / T and D / T are d / T = 5.0 and D / T = 5.0.

Example 3 As a thermoplastic resin film, a film mainly composed of polyethylene terephthalate and having a thickness of 2.5 μm and a crystallinity of 20% was used. Agent (Gaffax RL
210, manufactured by Toho Chemical Industry Co., Ltd. mp. Quaternary ammonium salt dodecyltrimethylammonium chloride as a 54 ° C.) and further the antistatic agent _{[C 12 H 25 N (CH 3} ) 2
[CH ₃ Cl] was applied at a weight ratio of 1: 1 to 0.2 g / m ² . A 16-dot / mm thin-film type thermal head (heating element main scanning length L
m: 31 μm, sub-scanning length Ls: 38 μm, heating element protective layer thickness T: 4.0 μm, feed amount in the sub-scanning direction during plate making
Ps: 62.5 μm), the probability of obtaining perforation is 1
The applied energy of only 00% was applied to the thermal head, and plate making including a black solid image portion was performed. The plate-formed thermoplastic resin film was set on a pre-port SS955 manufactured by Ricoh Co., Ltd., and printing was performed. As a result, an image having excellent solid uniformity and little set-off was obtained. There were no wrinkles on the image due to plate shrinkage. The printing durability was also at a level without any problem. Each d / T and D / T at this time is d / T
= 7.9 and D / T = 6.1.

Example 4 A film mainly composed of a copolymerized polyester as a thermoplastic resin film was substantially amorphous (having a crystallinity of 0.1).
%) Having a thickness of 7.5 μm and a melting temperature of 160 ° C., and a phosphate ester surfactant (Gaffa RL210, manufactured by Toho Chemical Industry Co., Ltd., mp. ) quaternary ammonium salt dodecyltrimethylammonium as further antistatic agent chloride _{[C 12 H 25 N (CH 3} ) 2 CH 3 Cl ]
Was applied at a weight ratio of 1: 1 to 0.2 g / m ² . This thermoplastic resin film is coated with a 12-dot / mm thin-film thermal head (heating element main scanning length Lm: 45 μm).
m, sub-scanning length Ls: 50 μm, heating element protective layer thickness T:
4.0 μm, feed amount in the sub-scanning direction during plate making Ps: 8
(3.3 μm) was applied to the thermal head so that the probability of obtaining perforations was 100%, and plate making including a solid black image portion was performed. The plate-formed thermoplastic resin film is used with Ricoh's Preport SS9.
When set to 55 and printing was performed, an image with excellent solid uniformity and little set-off was obtained. There were no wrinkles on the image due to plate shrinkage. The printing durability was also at a level without any problem. At this time, d / T and D / T are d / T = 9.
6, D / T = 8.3.

Example 5 A film mainly composed of a copolyester as a thermoplastic resin film was substantially amorphous (crystallinity of 1.0
%), A thickness of 5.5 μm, a melting temperature of 160 ° C., and a phosphate ester-based surfactant (Gafa RL210 manufactured by Toho Chemical Industry Co., Ltd., mp. quaternary ammonium salt dodecyltrimethylammonium chloride as a 54 ° C.) and further the antistatic agent _{[C 12 H 25 N (CH 3} ) 2 CH 3 C
1] was applied at a weight ratio of 1: 1 to 0.2 g / m ² . This thermoplastic resin film is 12 dots / mm
Thin-film partial glaze thermal head (heating element main scanning length Lm: 45 μm, sub-scanning length Ls: 50 μm, heating element protective layer thickness T: 7.0 μm, feed amount Ps in plate-making direction during plate making: 83.3 μm) Was applied to the thermal head so that the probability of perforation being obtained was 100%, and plate making including solid black was performed. This plate-formed thermoplastic resin film was set on Preport SS955 manufactured by Ricoh Co., Ltd., and printing was performed. As a result, an image having excellent solid uniformity and little set-off was obtained. There were no wrinkles on the image due to plate shrinkage. The printing durability was also at a level without any problem. Each d / T and D / T at this time is d / T
= 5.5 and D / T = 4.8.

COMPARATIVE EXAMPLE 1 The same heat-sensitive stencil sheet as in Example 1 was prepared by using a 16 dot / mm thin-film full-surface glaze thermal head (heating element main scanning length L
m: 45 μm, sub-scanning length Ls: 58 μm, heating element protective layer thickness T: 3.5 μm, and feed amount in the sub-scanning direction during plate-making Ps: 62.5 μm). When the thermal head was supplied with the applied energy sufficient to make the probability of perforation 90% or more, a large number of continuous perforations occurred in the sub-scanning direction, and the printing durability was very poor. In addition, under the applied energy condition where there is no continuous drilling in the sub-scanning direction, the probability of obtaining the drilling was low, and the filling of the solid image became poor. Each d / T at this time
And D / T are d / T = 5.0 and D / T = 1.3.

Comparative Example 2 A thermoplastic resin film mainly composed of a copolymerized polyester was substantially non-crystalline (having a crystallinity of 1.0
%), A thickness of 5.5 μm, and a melting temperature of 160 ° C., and a phosphate ester-based surfactant (Gafa RL210 manufactured by Toho Chemical Industry Co., Ltd., mp. quaternary ammonium salt dodecyltrimethylammonium chloride as a 54 ° C.) and further the antistatic agent _{[C 12 H 25 N (CH 3} ) 2 CH 3 C
1] was applied at a weight ratio of 1: 1 to 0.2 g / m ² . 16 dots / mm
Thin-film full-surface glaze thermal head (heating element main scanning length Lm: 45 μm, sub-scanning length Ls: 58 μm, heating element protection layer thickness T: 3.5 μm, feed amount Ps in plate-making direction during plate making: 62.5 μm) Was used to make a plate containing black solid. When energy was applied to the thermal head enough to make the probability of perforation being 100%, many continuous perforations occurred in the sub-scanning direction, and the printing durability was very poor. In addition, the thermal contraction of the stencil master which has been made, particularly locally in the sub-scanning direction or, depending on the image, becomes large, and wrinkles occur in the printed image. Each d / T at this time
And D / T are d / T = 5.0 and D / T = 1.3.

[0034]

According to the present invention, since the perforated dots are independent, image reproducibility is good, set-off is minimized, and a heat-sensitive stencil sheet without a support is particularly noticeable on an image due to plate shrinkage. An excellent print without wrinkles can be provided. Further, the durability of the plate making machine, particularly the thermal head, can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a thermal head.

FIG. 2 is a sectional view of a thermal head.

[Explanation of symbols]

 Reference Signs List 1 electrode 2 heating element Ps feed amount per dot Lm length of heating element in main scanning direction Ls length of heating element in sub-scanning direction 3 thermal head 6 insulating substrate 7 thermal resistance layer 8 heating resistance layer 9 electrode Layer 10 Oxidation-resistant layer 11 Abrasion-resistant layer 12 Heating part 13 Electrode part 14 Protective layer 20 Heating element heating position of nth dot 30 Heating element heating position of n + 1st dot

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41C 1/055

Claims (4)

(57) [Claims] The heat-sensitive stencil is obtained by applying heat energy to a heat-sensitive stencil sheet obtained by laminating a thermoplastic resin film and a porous support or a heat-sensitive stencil sheet consisting essentially of only a thermoplastic resin film by a thermal head. In a heat-sensitive stencil making method for forming a perforated image on a base paper,
The distance d (μm) between the heating elements of the thermal head and the thickness T (μm) of the heating element protective film satisfy the condition of the following formula (1), and the heating interval D ( μm) and the thickness T (μm) of the heating element protective film satisfy the following expression (2). 5 ≦ d / T (1) 4.5 ≦ D / T (2) 2. A heat-sensitive stencil making method for forming a perforated image on a heat-sensitive stencil sheet substantially consisting of only a thermoplastic resin film by applying thermal energy to the heat-sensitive stencil sheet using a thermal head. d (μm) and the thickness T (μm) of the heating element protective film satisfy the following expression (3), and the heating interval D (μm) of the heating element of the thermal head in the sub-scanning direction and the heating element protection film A heat-sensitive stencil making method wherein the thickness T (μm) satisfies the condition of the following formula (4). 5 ≦ d / T ≦ 10 (3) 4.5 ≦ D / T ≦ 9 (4) 3. The heat-sensitive stencil making method according to claim 1, wherein the thickness of the heating element protective film of the thermal head is 3.5 to 7.0 μm. 4. The heat-sensitive stencil making method according to claim 1, wherein a distance between the heating elements of the thermal head and a heating interval of the heating elements in the main scanning direction are both 17.5 μm or more.